Title of Invention

A FLOOR CLEANNING DEVICE

Abstract

A floor c1.eaning device is described wherein the rotating drum located between the rotating brushes is of composite construction, having an outer layer of nitrile rubber. Extensions are provided On the arms that carry the device supporting rollers. Means are provided to interpose a spacer between the pair of said extensions on the side of the device and a spacer member comprising a series of spacer elements on the other. The former is to prevent roller retraction during transport of the device and the letter provides roller position control for brush -wear compensation or for varying brush pressure. A cogged belt drive is provided. Several other improvements such as in the brush drive and mounting systems, motor ventilation system, motor switching arrangement and. device 1oocking are described. A spring means prevents idling contact of rollers on floor during operation. A dual-purpose auxiliary tank is provided.

Full Text

This invention relates to floor cleaning devices and more particularly to gravity type floor cleaning devices wherein the fluid used for said cleaning flows from a tank thereof to the floor under gravity. A floor-cleaning device of the prior art basically comprises a rotatable drum and two brush members, the latter being counter-rotating. One said brush member is located fore and the other aft of said drum. During operation the said rotating brushes wash/scrub the floor, water for said washing/scrubbing being provided from a water tank located on the device. The floor-cleaning device of the invention comprises the same basic construction as just described hereinbefore. The axes of said drum and brush members are generally transverse to the forward direction that is to the general direction of motion of the devfce during operation. The device therefore, comprises a longitudinal axis that is generally parallel to said forward direction and a transverse axis that is taken to be coincident with the axis of said drum. All directional and locational references in the specification both with respect to the prior art device and device of the invention are in reference to said two axes and to the said forward direction. The term 'counter-rotating brushes' in this specification is understood to mean that the rotation of one brush is in an opposite sense to the other and that said rotations are such that the two said brushes direct/throw the water arising from said washing/scrubbing towards said drum located therebetween, A said brush member in the device of the invention may comprise a single brush or a plurality thereof. In case of the latter, the individual brushes (brush segments) may have different configurations within the scope of the invention. However, references in this specification are only to 'brushes'. This has been done in the interest of conciseness and it is to be understood that the scope of the term 'brushes' also includes said constructions wherein a brush comprises two or more said brush segments. The application of the floor cleaning device of the invention is not limited to floor cleaning and extends to the cleaning of other surfaces such as platforms, terraces, pavements and others. Thus, the device of the invention is really a surface cleaning device although in this specification the term 'floor cleaning device' is uniformly used. This is for the reason that said term 'floor cleaning device' happens to be a commonly used expression in the field/trade for such surface cleaning machines. Therefore, in so far as this specification is concerned the scope of the term 'floor' is intended to include all said other surfaces. For said washing/scrubbing, water or other cleaning fluids such as a detergent liquid or a detergent solution is used. However, in the description and claims hereinbelow reference is made only to water as the said washing/scrubbing medium. This is in the interests of conciseness and clarity of the specification and is without limitation to the scope of the invention and in so far as this specification is concerned the term 'water' is intended to include in the scope thereof all said other cleaning fluids unless otherwise required by the context. Reference has been made hereinabove to the said solid matter and wash (waste) water resulting from the said washing/scrubbing process. In the interests of conciseness this has been shortened to 'wash water' or ' waste water' in this specification. Similarly, the term 'washing/scrubbing' has been shortened to "washing'in the further specification hereinbelow, - A prior art floor cleaning device, therefore, comprises a said rotatable drum, said rotatable fore and aft brushes, a water tank that provides water for said washing and a wash tank (collection tank) where said wash water resulting from said washing of the floor is collected. Said drum is provided with a suitable scraper tiiat, during operation, directs/deflects said wash water from the drum surface into said collection tank. The prior art device further comprises a set of rollers (wheels) by means of which it is moved/rolled along the floor. There are two modes of movement of the prior art device and the device of the invention, namely, the operation and transport modes. In the former, the device brushes are in contact with the floor such as to carry out said washing/scrubbing action while in the latter said brushes remain clear of the floor. It will be clear that the reason for holding said brushes clear off the floor in the transport mode is to minimise the friction against the floor during said transport. Absence of brush contact with the floor during said transport reduces the effort required in said transport, that is, in pushing the device from one location to another. The said brush raising/lowering is carried out by means of the device handle. Said handle is in the vertical orientation (position) in the idle state of the device. In said idle state, said device rollers are down (lowered) and support the entire weight of the device while said brushes thereof are in the raised position thereof, that is, dear off the ground. It will be seen that the effect of retraction of said rollers is the lowering of the device body and brushes. In the prior art device and the device of the invention therefore, said raising/lowering of brushes is achieved by moving said rollers downwards or upwards. For this purpose, said handle is suitably linked to said rollers by a mechanical linkage such that moving said handle from the idle position towards a diagonal position thereof brings down said brushes into contact with the floor and vice versa. Further movement of the handle in the same direction causes further lowering of brushes. During this process, said rollers are retracting upwards and increasing portion of the weight of the device gets transferred from said rollers onto the said brushes. Said mechanical linkage acts on one said roller referred to herein as the thrust roller. Said linkage comprises a link and guide arrangement which has a longitudinal member one end of which abuts the roller-carrying arm of said thrust roller. When said handle is moved towards the idle position thereof downward thrust is applied on said thrust roller through said longitudinal member the effect of which is to raise said brushes and the device housing. In the reverse movement of said handle, the restraint on the upward motion of said thrust roller is removed causing it to retract under the effect of the weight of the device. In other words, the device body (housing) together with the device brushes moves towards the floor. The upward retraction of said thrust roller and with it, of all the other rollers because they are dynamically linked to each other, can be considered to comprise three parts. In said idle position (state) of the device said rollers are in their ..towermost .position called their idle position. At this point, said rollers are bearing/supporting the full load of the device. During said upward retraction a point is reached whereat said brushes make contact with the floor. This point on the roller trajectory is referred to herein as the contact point. Said contact point is the point of commencement of transfer of device weight from said rollers to brushes. This weight transfer continues till the zero load point is reached. TTie significance of said zero load point is that at this point and onwards the entire weight of the device is borne by said brushes and the load on said rollers is substantially nil. With further said retraction, said rollers are lifted clear off the floor. The range of said roller trajectory between said contact and zero load points is referred to herein as the control zone. It will be seen that at each point in said control zone, a different value of the brush pressure on the floor is obtained corresponding to the different values of the portion of the device weight borne by the brushes at these points. This is the basis of the brush pressure control means in the prior art device and the device of the invention. A series of stops are provided for said rollers in said control zone thereof, which offers a series of said brush pressures. However, the method of providing said stops in the device of the invention is different from that in the prior art device. Said method of the device of the invention is novel and is easier to operate, requires less effort to operate and is more user-friendly. Said brush pressure control means of the invention is discussed further hereinbelow. It will be observed that said brush pressure control means also constitute means for brush wear compensation as the brushes can be advanced by said method of the invention to compensate the wear of said brushes. The extent of said control zone in which the pressure of a set of brushes could be varied would depend on the brush characteristics such as size, stiffness. and others. As mentioned hereinabove, the load on sakJ rollers at said zero load point is substantially nil and the rollers remain in idling contact with the floor. In the prior art device this idling contact causes smearing of the floor during operation of the device. In the device of the invention, this has been prevented by lifting up said rollers beyond said zero load point by suitably located spring means. This is novel and unlike as in the prior art device and is described furt:her hereinbelow. The means for said control stops is independent of said spring means and therefore when said rollers are in said control zone they cannot be lifted out therefrom by said spring means as they are restrained by said stops. Said smearing can also occur in the said control zone wherein said rollers are in pressure contact with the floor as they are bearing more or less of the device weight. This drawback of the prior art device has been overcome in the device of the invention by adoption of a novel, dual-moulded construction for said rollers wherein the material used for the outer (and/or tread) part thereof is such that it does not leave smear marks on the floor during operation. This is elaborated further hereinbelow. Said handle in the prior art device is a generally U-shaped member, the arms thereof being pivotably mounted on said housing. Said pivoting is about an axis transverse to said longitudinal axis of the device such that said handle is pivotable in a generally vertical plane containing said longitudinal axis. In the idle position of the prior art device, said handle is held vertical. Said handle is moved into one of the diagonal positions thereof to enable one to push the device either during operation or during said transport of the device. During said pushing, said handle is held in the particular diagonal position that matches the height and conforms to the convenience of the operator. Said mechanical linkage is such that movement of said handle towards the diagonal positions thereof causes the said retraction of rollers and the equivalent lowering of said brushes. It will be observed that when said handle is moved to a diagonal position thereof to enable the operator to push the device for transporting it from one operational location to another, said retraction of rollers, that is, lowering of brushes must be prevented. Means is provided in the prior art device that prevent said roller retraction when said handle is moved to get the device into the transport mode as opposed to the operational mode thereof. Said means is referred to further hereinbelow as retraction prevention means, retraction locking means or retraction cut-off means or cut-off means for short. Said device body (housing) houses said drum and brushes and further comprises of left and right side boxes (side housings). One said side housing houses the electricals of the device while the other houses the drive system thereof. The electric motor (prime mover) of the prior art device is housed within said drum. The drive system of the device comprises two drive trains one each extending to each of said two counter-rotating brushes. Being located in an enclosed space, it is necessary to provide suitable cooling means for said motor. Said cooling/ventilation means comprise suitable passages/openings in said side housings (side boxes) and in the two housing sidewalls such as to provide suitable entry and exit for the cooling/ventilating air. For effective said washing/scrubbing action, it is necessary for water coming from said water tank to be generally uniformly distributed across the operational width of the device. For this purpose suitable water distribution means are provided in the prior art device. Said water tank comprises a discharge chamber into which water is released from the storage section of said tank through a discharge valve located ■ -'■ . - '■■■.:- i.--^f: ":- " ■'-., '. ' - ■ •■; --■-■-ii;^,;'^, ;■-■-. therebetween. Said valve is referred to further hereinbelow as the water tank discharge valve. The function of said discharge chamber is to distribute the water over the operational width of the device and comprises a series of holes for this purpose through which the water drops onto the floor. Described hereinabove are the major features of the prior art floor-cleaning device. Same said major features are present in the device of the invention but their construction is different from that in the prior art device. In case of some said major features, improvements have been provided in ttie device of the invention while in others totally novel constructions have been adopted in the device of the invention. The said major features in the device of the invention such as said drum, said retraction means, said retraction locking means, said rollers, said driving system, said cooling means and others, in fact, are of novel, different and improved construction in comparison to those in the prior art device. In addition, this invention provides for further novel features not found in the prior art device. Said improvements in said major features, said novel major features and said further novel features are elaborated and described further hereinbelpyy. Prior art: provides for a bare drum that is usually made of PVC (Polyvinyl Chloride)-Such a drum is susceptible to abrasion by the solid partjculate matter in said waste water. This results in the scouring of the drum surface and over time to formation of large ruts through which some of said waste water bypasses said scraper and ends up in said drum or housing or both. Some said wash water ends up on the floor, thus, reducing the cleaning efficiency of the device. Thus, there are two consequences of said abrasion, reduced working life of said drum and reduced efficiency of the device. This invention provides for a composite drum and this Is novel. Said drum may be formed from a composite material by known processes of fabrication such as rolling, moulding or others or alternatively, said composite structure may comprise a drum made of a base material over which a covering is applied. Said covering may comprise material attached to said drum surface by any of known means or may comprise material deposited or moulded thereupon. The purpose of the inner layer(s) is to impart strength and rigidity to the said drum while the outer layer(s) thereof provide the necessary abrasion resistance and resistance to swelling under the action of mineral oils and other materials. This invention has investigated several coating materials, such as, for example, natural rubber, neoprene, nitrite rubber, mixture of natural rubber and nitrite rubber and others and has arrived at a covering material that is not only highly resistant to abrasion but furthermore, is stable to the swelling action of said waste water which may contain components that cause swelling in some materials. Preferably, said covering material is nitrite rubber or neoprene and more preferably nitrite rubber. Said drum cover is moulded from nitrile rubber and is fitted onto the PVG base-drum-by a process similar to shrink fitting. Said nitrile rubber moulding may comprise the usual additives such as accelerators, antioxidants, sulphur, carbon Wack and others. With similar working conditions, the working life of the coated drum of the invention was found to be greater by a factor of about 15-20 over the bare PVC drum of the prior art device. Said drive system of prior art device comprises a pinion on the shaft of said motor. Said pinion drives two helical gears located one on each side thereof. A gear train extends from each of said two helical gears which are referred to herein as the drive gears or driver gears. One said train connects to one said brush and the other to the other said brush. Each said train comprises three gears namely.one said drive gear, an intermediate gear and lastly the driven gear mounted on the brush shaft. An extra gear is provided in the gear train extending to the rear (aft) said brush. Said extra gear is on a common shaft with a small pinion that engages with the gear teeth located on the inside surface of said drum and provides drive thereto. The drawbacks of said gear trains of prior art are their higher power consumptton and their higher sound level. This invention has adopted a belt system, which not only draws less power but also is quieter in operation. This is novel. Preferably, said belt system is of the cogged belt type that offers a positive drive without slippage and furthermore does not require any lubrication. Each said train in the device of the invention comprises three cogged wheels, the said drive and driven wheels and a belt tensioner wheel. The train for the said aft brush includes a further wheel that is mounted on a shaft that is common with a small pinion that engages with the teeth provided in the inside surface of said drum. A further advantage is . -the longer working life of the cogged wheel trains over that of the geared wheel trains. In the device of the invention, the sound level Is down to 65-70dBA from the 80-90dBA found in the prior art device. The average woridng life of the cogged wheel trains was observed by this inventor to be about 5-6 times greater than that obtainable with the prior art device drive trains. In the prior art device the motor pinion simultaneously drives the two said driver gears of the two said gear trains. In the device of the invention, the motor pinion drives only one of said two driver gears associated with the two cogged wheel trains thereof. The second driver gear is driven by the first, the two being coupled to each other. This arrangement in the device of the invention is novel and provides for ease of assembly and, furthermore, scope for accommodating a certain amount of misalignment, if any, of the components and/or the device housing. Said prior art device comprises four said rollers. A pair of rollers is associated with a shaft; such that the said device comprises two said shafts, which carry four said rollers.in all and which are positioned transversely of the device. Each said roller is rotatably mounted at the end of an arm. Each said transverse shaft engages with two said arms one located at each end thereof and thus carries two said rollers one at each end thereof. Said mechanical linkage in the prior art device comprises a link and guide arrangement located at the forward roller on the right hand side of the device. This roller Is referred to herein as the thrust roller, as mentioned hereinbefore. The motive impulse generated by the movement of said operation handle is transmitted to said thrust roller. When said handle is moved from any diagonal position (orientation) thereof during said operation mode to the vertical (idle, rest) position (orientation) thereof a downward thrust is applied to said thrust roller causing said device housing together with said brushes to move upwards from contact with the floor. During the reverse motion of said handle, that is, from the vertical position thereof towards the diagonal positions thereof no direct pull is exerted upon said thrust roller. However, as the restraint on said thrust roller is removed said thrust roller and the other rollers all retract upwards under the effect of the weight of the device. It will be seen that said upward retraction brings down said brushes into contact with the floor. The device of the Invention also comprises four said rollers disposed in a manner similar to that in the prior art device. Each said roller is rotatably mounted at one end of an arm, two said arms engaging with a transversely disposed shaft, one each at each end thereof. The device of the invention also comprises of said mechanical linkage connecting said handle thereof to said rollers, said linkage including a said link and guide arrangement that transmits impulse from said handle to one said roller referred to herein as the said thrust roller. In the prior art device said roller arms comprise generally of two parallel plates each. Each said roller is rotatably mounted between said plates at one end of the pair, the other end whereof engages with a said shaft. Said shaft is hexagonal in section and locks in the hexagonal slots located in said pair of plates at each end thereof. Said two plates of each arm each have a set of gear teeth at the shaft end thereof. Said gear teeth of the two said anns on each side of the device when assembled engage with each other. It will be seen that any upward or downward motion of said thrust roller will get transmitted to the other three rollers through the means of said engaged gear teeth and said shafts that form a dynamic linkage between said rollers. In the prior art device, when said brushes thereof are lowered in the operation mode, that is, when said rollers are retracted the weight of the devices is then borne by said two brushes. However, there is no provision for holding up said retracted rollers In the prior art device and consequently while bearing substantially zero load they nevertheless remain in idling contact with the floor during a floor cleaning operation leaving tracks/marks thereon during operation. The said gear engagement of the roller carrying arms in the prior art device is not a fully satisfactory arrangement. As described hereinabove, said gear teeth in the prior art device are cut/formed on said plates because of which their engagement occurs only over a comparatively small area of contact. This is likely to lead to distortion of said teeth and/or of the remainder of said plates during operation. The operation of the engaged teeth is furthermore noisier. These drawbacks of the prior art device have been removed in the device of the invention. In the device of the invention, the hollow said arm is replaced by a solid one wherein said teeth extend over the full width thereof, that is, substantially over the full width of the said rollers. Thus the area of contact in said teeth engagement is considerably more in the device of the invention than in the prior art device. This ensures a smoother, misalignment-free and quieter operation of the said gears in the device of the invention. To overcome the problem of said unseemly tracks, this invention provides for spring loading of said arms as mentioned hereinbefore. This is novel. In the device of invention, a suitable spring is placed between said forward and rearward arms on one side of the device. For this purpose, each said arm is provided with an extension on the other side of the said geared portion thereof. A spring is connected between said two arm extensions on a side of the device. A pair of such arms, spring-loaded or otherwise, is in the general configuration of a pair of scissors wherein the fulcrum of lever action lies in or at said engaged gears. Such a spring may be provided on one side of the device or both. The provision of said spring(s) ensures that the said rollers remain clear of the floor when said rollers are not bearing the device load. When the device is operating in said control zone said spring(s) hold said thrust roller tightly against the selected said stop. This prevents any rattling or vibratory movement of the rollers unlike as in the prior art device. Said arms of the generally U-shaped operating handle in the prior art device engage with a pivot shaft that is mounted on said body and that is positioned transversely of the device. Slots on said arms engage with a pair of flats located at each end of said pivot shaft. Said pivot shaft is linked to said rollers such that operation of said handle and the consequent turning of said pivot shaft causes the raising and lowering of said brushes. Said slots on the arms enlarge into circular holes at the lower ends thereof such that said slots are in the general shape of inverted keyholes. When it is required to transport the prior art device, said operating handle which is vertical in the idle position thereof is raised such that said engagement between said arm slots and flats is broken. Said handle would then be free to be swung into a diagonal position (pushing position) thereof without said mechanical linkage coming into action. It would be clear that said engagement between said handle and pivot shaft having been broken the movement of the handle towards any diagonal position thereof would not produce said retraction and said lowering of brushes. This is the arrangement of said retraction locking means in the prior art device of the invention. The lifting of said operating handle in the prior art device so as to disengage said slots and flats for the purpose of bringing the device into the transport mode thereof is more often than not cumbersome, difficult and time consuming in the prior art device as the handle does not disengage so easily and quickly each time. This is a drawback in the prior art device that has been rectified in the device of the invention. This invention provides for a quite different and novel arrangement of said retraction locking (cut-off) means. It will be observed that when said rollers retract upwards said pair of extensions (of said roller mounting arms) on both sides of the device draw close to each other. Thus, when said operating handle is moved from the idle (vertical) position thereof towards a diagonal position (an operating position) thereof the said pair of extensions on each side of the device close in towards each other. This invention provides for the interposition of a suitable spacer member (spacer piece) between a pair of said extensions at least on one side of the device so as to prevent said closing-in and therefore, said roller retraction. Thus, when said spacer piece is put in position and said device handle is moved towards a diagonal position thereof, said housing and brushes do not get lowered towards the floor. In the device of the invention said spacer piece is located at foot level so that it is most conveniently pushed/slid into position between said pair of extensions by pushing down the pedal portion thereof with a foot. This inventor observes that the operation of the retraction locking means of the invention is quicker, more user-friendly and does not involve hits and misses and iBlse starts as in the prior art device. Said retraction locking means of the invention may be located on either, or each side of the device. It will be seen that any wear of the brushes would reduce the degree of brush contact with the floor. It then becomes necessary periodically to lower said brushes a bit more so as to restore said degree of contact. This is achieved by increasing the degree (amount) of said retraction when going from idle position to the operation mode. TTie arrangement for said brush wear compensation in the prior art device comprises an abutting member that abuts against a said roller arm and functions as a stop (limit) to the upward retraction said arm and therefore, of the associated roller thereof and as all said rollers are dynamically linked all said rollers are similarly stopped (limited) in their upward retraction. Means is provided by means of which said abutting member can be advanced or withdrawn so as to set said stop (limit) at the desired point. Said means comprises a cam-type (eccentric) member which when turned in one-direction advances said abutting member and therefore, said limit. When said means is rotated in the opposite direction it sets a new said limit to which said abutting member withdraws allowing said rollers to retract that much further under the effect of the weight of the device-Said means is operated by the knob thereof. It would be clear that as said rollers are dynamically linked any said limit (stop) provided would apply unifomr>ly to all four rollers of the device. This invention provides, for a novel and different said brush wear compensation means (adjustment means), which is more easy, convenient and operator-friendly. The brush wear compensation means of the invention consists of controlling the closing-in of a said pair of extensions during said retraction. For the purpose, a stepped spacer member is provided which is movable vertically up and down and which in the different positions thereof restrains and limits said closing-in of a said pair of adjacent extensions to different extents. It will be seen that controlling said dosing-in controls said roller retraction and consequently the extent of said brush lowering towards the floor. Thus, in the device of the invention, increase of said lowering to compensate said brush wear involves resetting said stepped spacer means of the brush wear compensation means. As mentioned hereinabove, said brush wear compensation means also constitutes the brush pressure control means of the device of the invention in that by the use of said stops (limits) different values of the brush pressure on the floor can be obtained as elaborated earlier hereinabove. Said ventilation means in the prior art device comprises air inlet and air outlet holes located in the said side housings. Said holes being located fairiy close to the floor in the prior art device, the ingoing air tends to pick up drops of waste water, which could interfere with operation of the device motor. In the device of the invention, said inlet and outlet holes/openings are located at a somewhat higher level so as minimise/eliminate entry of said waste water into the drum and the motor. Further said openings are provided with suitable grilles/baffles/louvers that deflect said waste water drops and prevent their ingress into the drum interior. This is novel. This invention also provides for a fan impeller of the axial flow type located on the shaft of said motor. Said fan draws cooling air into the drum interior from one side of the device and expels it on the other side thereof. The provision of a said fan is novel and unlike as In the device of prior art. A novel arrangement for brush removal and replacement that is quicker, easier and more user-friendly is provided in the device of the invention. In the prior art device, a said brush is slidable mounted on the shaft thereof. Said shaft is of hexagonal section which engages with a similar sectioned shaft cavity (hollow) in the brush. Removal of a said brush in the prior art device consists of pulling out said hexagonal shaft thereof from one side of the device. When it is desired to re-assemble said brush, it is positioned and aligned between the two bearings thereof located in the two said side housings and the shaft thereof is slid into position from one side of the device. In the re-assembly procedure of the prior art device the problem is getting the brush to be correctly aligned the first time and often several attempts are required to obtain correct said alignment which makes the said procedure of the prior art device cumbersome. This drawback/difficulty has been overcome in the device of the invention. This has been achieved in the device of the invention by the provision of a pair of arcuate support ledges (brackets, lips) on the two said side housings for each said brush. Said ledges that are of a small width project inwards from said side housings. A said brush is provided with two said ledges one on each said side housing. Said ledges are positioned such that when a brush is placed thereupon the said shaft hollow thereof is properly aligned with respect to the two bearings thereof located in said side housings. It is then possible to slide said shaft into position quickly, easily and without any difficulty in the device of the invention. Said sliding-in is further helped and made easier by chamfers provided at the ends of said brush shafts and on the brush bearings located In said side housings. In the prior art device, the starting switch that starts the drive motor thereof is operated through said mechanical linkage. The movement of said device handle towards an operating position thereof causes the said motor to be switched on through said linkage. Prior art further provides an isolation switch which is located on a small console positioned near the upper end of said generally U-shaped operating handle, that is, close to the point where said handle is gripped by the operator. The power cable (running cable) of the device coming from a power source such as, for example, a wall socket comes to said isolation switch and from there runs down the said handle to the side box where said electrical circuitry of the device is located. The undoubted convenience of said location of the isolation switch dose to said upper end of the handle in the prior art device is somewhat overshadowed by the possibility of said switch, console and the handle becoming live by accidental dripping or splashing of water thereupon. The probability of said splashing is not negligible particularly as the auxiliary water tank of the device is located on said handle close to, and below the position of said console. This tank, which is detachably mounted on said handle, is regularly removed for cleaning and re-filling and then mounted back on said handle. Said risk and danger of said handle and body becoming live has been eliminated in the device of the invention. The power cable in the device of the invention oomes from said source directly to the said side housing that houses said electricals of the device. Said electrical circuitry and components are provided on a detachable box module that is mounted in said side housing and that when closed is splash-proof. A function of said isolation switch in the prior art device is to prevent starting of the brush and drum motor by any inadvertent lowering of said handle towards the operating positions thereof. This functional objective is achieved in the device of the invention in a novel manner by providing a mechanical lock which must be opened for the said handle to be lowered from the vertical (idle) position thereof towards any diagonal, that is, any operating position thereof. Said mechanical lock which comprises a spring-loaded snap-action lever comes into effect automatically each time said handle returns to the vertical (idle) position thereof. Said snap-action lever locks onto a part of said link and guide arrangement whenever said handle returns to the vertical position thereof in a manner such that said handle cannot be lowered unless and until said lock is opened. Said mechanical lock is located on said housing and is provided with a foot pedal that is depressed to release said lock and allow the lowering of said handle. Thus, the invention provides a novel, non-electrical, that is, a mechanical safety locking means to prevent said inadvertent lowering of handle and starting of the device motor. The function of the said auxiliar/ tank in the prior art device is to provide storage for additional water that can be used in the event of the said water tank of the device running dry. Said water tank is located in the device in the front part thereof above said fore brush thereof. A discharge valve is provided thereupon which discharges into the discharge chamber of said water tank from where water flows onto the floor through a series of holes located therein on a transverse axis. Said water tank discharge valve is operable by means of a handle located at the said top part of the device handle. Said auxiliary tank discharges into said water tank through a stop valve. When opened said valve allows flow of fluid from said auxiliary tank into said water tank. The function of said auxiliary tank in the device of the invention is not only as a storage for reserve water as in the prior art device but also to act as a storage for a supplemental cleaning fluid that can be simultaneously discharged onto the floor premixed with the water from said water tank. The auxiliary tank of the device of the invention is, therefore, a dual-purpose tank. Thus, if water is being discharged from said water tank it can be continuously mixed with the supplemental liquid flowing in from said auxiliary tank. The liquid in said auxiliary tank could be a detergent liquid or a detergent solution which it may be desired to mix with the water from said water tank before it drops into said discharge chamber and from there onto the floor. This is novel. The discharge valve from said auxiliary tank in the device of the invention connects to said water tank discharge valve which is a special dual-purpose novel valve which when opened allows fluid from said auxiliary tank to flow into said storage section, mix with the water (or other fluid) present therein and then flow out into said discharge chamber. Said valve thus comprises two passages both of which can be simultaneously opened or closed by means of the valve handle. One said passage is for the auxiliary tank fluid to flow into said storage section and the other for the fluid (single or mixed) in said storage section (chamber) to flow down into said discharge chamber. Said auxiliary tank comprises a spring-loaded valve at the bottom thereof that automatically gets opened upon placing of the tank in position on the device handle. Said auxiliary tank valve is connected through a flexible tube/hose to said water tank discharge valve. The tank has a shroud-like extension at the bottom thereof the purpose whereof is to protect said bottom valve from damage by accidental knocks during handling of said tank. Said shroud also serves as a receptacle for sediment and solid matter if any, in the tank contents. The fitment of said auxiliary tank to said device handle in the prior art device is by fasteners. As said auxiliary tank is required to be periodically removed for cleaning and/or refilling the doing and undoing of said fasteners is a time-consuming and cumbersome operation in the prior art device. The fitment of said auxiliary tank in the device of the invention is considerably simpler and comprises a snap-fit arrangement by which it is easily and quickly mounted or detached from said device handle. Further, retaining means comprising a set of swing-arm type brackets are provided to prevent the accidental coming off of said snap-fitted tank. Said swing arms are spring-loaded. It will be seen that said fitment and detachment of the auxiliary tank in the device of the invention does not require any handling of fasteners but merely involves the moving of said swing arms and then easily and simply pulling the tank out or putting the tank into the snap-fit arrangement thereof. The discharge valve of said water tank in the device of the invention is operated by means of a valve-operating handle located at, or close to the said top part of the device handle as in the prior art device. But in the device of the invention the linkage between the said valve handle and the said valve is by means of a bowden cable unlike in the prior art device. Said auxiliary tank in the device of the invention is also designed to be free-standing unlike in the prior at device. This is an added convenience when said tank is desired to be detached and set aside for any reason. Said auxiliary tank is an optional accessory. Means comprising a set of hooks is provided in the prior art device on the said handle thereof for coiling the power cable (running cable) thereof when the device is not in use. Use of said means is somewhat cumbersome as the undoing (removal) of said coils of cable from said hooks is often quite time-consuming and inconvenient. The device of the invention provides said spring-loaded swing-arm brackets on which the winding and unwinding of said cable is a very easy and quick operation. In particular, the entire cable coil is very easily slipped off said swing-arm brackets when the device needs to be operated. A novel construction of said rollers is provided in the device of the invention. In the prior art device, said rollers are of a single material of construction and are made generally of one of the low-friction plastics such as nylon. The object here is to minimise the friction in the rotation thereof around the axles thereof. The implications and consequences of the material on the rolling performance of said rollers on the floor have not been considered in prior art. This invention has considered the material specifications that would be appropriate for the floor contact parts and for the axle contact parts. Said floor contact part (the outer part or the tyre part) of said rollers must be hard-wearing, abrasion-resistant and of such a material that can withstand the different environments encountered in floor-cleaning such as for example, in factories. It must also not leave smears or marks on the floor during said cleaning or otherwise. Thus, this invention provides for a composite construction of said rollers such that they comprise a radially inner part of a material having low friction characteristics and a radially outer part that is made of a material that is sufficiently hard and corrosion and wear-resistant giving it a long life and that does not smear or mark the floor during operation or said transport. Said composite construction of the rollers may be by the process of dual moulding or by any other process. In the device of the invention, said rollers thereof are further provided with side covers that protect the axle regions thereof from ingress of dirt, wash water and foreign matter. According to the invention, therefore, there is provided a floor cleaning device that comprises, i. a pair of counter-rotating brushes located fore and aft of a rotatable drum that during operation throw/direct the wash water arising from said floor cleaning onto said drum; ii. a water tank that discharges water onto said floor for cleaning thereof; a collection tank wherein said wash water is collected, said wash water being deflected/directed thereinto by a scraper engaging with said drum; a set of rollers/wheels on which the device is moved/rolled along during transport thereof from location to location and that, when the device is to be operated, are retracted such as to cause lowering of said brushes into contact with the floor, each said roller being rotatably mounted at the end of a roller-carrying arm; a pair of transverse shafts, the ends thereof being in engagement with said arms; geared engagement between the pair of said arms on both sides of the device through geared portions provided thereon resulting in a dynamic linkage between all four said rollers; extensions on the pair of said arms located on one or both side of the device,said pair(s) of extensions closing-in towards each other during said retraction^ a generally-U-shaped operating handle mounted on the body (housing) of the device and pivotable between a vertical orientation (idle position) thereof to a diagonal orientation (working position) thereof for pushing the device during operation or during the said transport thereof; a mechanical linkage containing inter alia a link and guide arrangement, connecting said handle and at least one said roller such that said rollers are retracted upon movement of said handle into a working position thereof; a retraction prevention means for preventing said retraction when the movement of said handle into a said working position thereof is required for the purpose of said transport; xi. a brush wear compensation means that provides increased lowering of the said brushes such as to compensate for the wear thereof or otherwise to provide increased brush pressure on the floor; xli. a drive system linking the electric motor (prime mover) of the device with said rotatable drum and brushes, the device being with or without said « prime mover thereof; and xiii. optionally an auxiliary tank for holding water or other cleaning fluid; and wherein said drum is of a composite construction. The device of the invention comprises a generally rectangular shaped box that constitutes the body (housing) of the device and that houses said two brushes, drum with said scraper thereof and the two said transverse shafts that carry the rollers of the device. Said housing comprises two compartments, one on each side thereof, that are referred to herein as the side housings. The housing along with said side compartments are of aluminium alloy construction. Said box constituting the housing may be of other shapes and configurations and of other materials of construction within the scope of the invention. The device further comprises an operating handle that is of a generally U-shaped configuration. It is fabricated mainly out of pipe material and may comprise one or more cross stays. The arms of the U-shaped handle are pivotably mounted one on each side of the device housing. Said U-arms engage with a transverse shaft located on said housing in the central portion thereof. Said pivoting permits the said handle to be moved in a generally vertical plane containing the longitudinal axis of the device. The vertical orientation of the handle is the rest or idle position thereof. For operation of the device or for said transport thereof it is necessary to bring said handle into a diagonal position (orientation) thereof. Said handle may be held in any of several said diagonal positions thereof during operation. The choice of a particular angular orientation depends on the operational convenience of the operator. Other configurations and constructions of said handle are within the scope of the invention. Said water tank of the device is located on the said body (housing) forward of said handle and above said fore brush. Said tank is easily removable such as to uncover and gain access to, said fore brush over which it is located. However, said brushes can be removed for cleaning or replacement v/ithout having to remove the said water and collection tanks located thereabove. Said tank is generally rectangular in shape and is constructed of plastics but other shapes and materials are within the scope of the invention. Said tank is provided with a drain valve (water tank discharge valve) that drains water therefrom into said discharge chamber located below said valve. As mentioned hereinabove, said valve is a novel, special purpose valve, A line of holes extending transversely is provided in said discharge chamber through which water flows onto the floor belovv. Said line of holes is positioned slightly forward of said fore brush. Other means of distribution of water from said tank, other locations and configuration of said line of holes are within the scope of the invention. Said drain valve (water tank discharge valve) comprises a spring-loaded spindle that is operated by the valve-operating handle thereof located at the top part of said device handle, the connection (linkage) being through a bowden cable. Other types of said valves, other methods of operation and of making said connection are within the scope of the invention. Said collection tank is generally similar in construction to said water tank. This also applies to the mounting arrangement thereof on the device body. In the assembled device, said tank forms a cover over said aft brush, which can be easily lifted off to uncover and gain access to, said aft brush. Both said water and collection tanks are provided with lids. Both tanks are easily detachable for cleaning and/or refilling. Said water discharge on the floor for cleaning is along a transverse line located slightly forward of said fore brush. Other configurations of said water discharge arrangement and of the locations thereof with respect to said fore brush are within the scope of the invention. Said fore brush which is located underneath said water tank comprises a hollow tubular member upon which are located the bristles thereof. Said hollow of the tubular member houses the brush shaft that is of hexagonal cross-section and extends in the transverse direction. Engagement is provided between said shaft and the tubular member at one or more locations inside said hollow. The shaft bearings are located in said side housings. The brush assembly is designed for easy and quick removal and assembly of the brushes for cleaning and/or replacement. Said shaft is locked in position by means of spring-loaded ball operated lock means located at both ends thereof. Said brushes are of generally cylindrical configuration but can be of other types. A large range of materials is available for construction of the brushes and bristles thereof. The device may include different brushes for different floor conditions and floor specifications. As mentioned hereinabove, said brushes may comprise one or more individual brush segments within the scope of the invention. The construction of said aft brush and the mounting and driving arrangements thereof are generally identical to that of said fore brush and the comments and observations made in respect of said fore brush are also applicable to the said aft brush. In fact, in the device of the invention, said fore and aft brushes are interchangeable but could be otherwise within the scope of the invention. Said brushes are driven by cogged belt drives. The device motor is provided with a pinion on the shaft thereof, that drives one of two coupled helical gears located one on each side thereof. Said two helical gears are each on a common shaft with a cogged wheel, the two cogged wheels being the driver wheels for the two cogged belt drives that extend therefrom to the two brushes. Both said cogged belt drives include a belt tensioner wheel and furthermore, the cogged belt drive to the rear (aft) said brush includes an additional wheel that drives said drum. Said additional wheel is on a common shaft with a toothed pinion that engages with similar teeth provided on the inside surface of said drum. Other belt drives are within the scope of the in/ention. The cogged belt drive of the invention offers reduced noise levels and extended life and is lighter in construction in comparison to the helical gear drive system of prior art. Said drive system is located on one side of the device and is housed in one said side housing. Other locations and configurations are within the scope of the invention. Within the scope of the invention the device of the invention may be with the motor thereof or without. Said mechanical linkage extends between said device operating handle and one said roller, referred to as the thrust roller. Said linkage connects to said transverse shaft of the device handle at one thereof and to the said arm of the thrust roller at the other. Said link and guide arrangement of the linkage is located at said thrust roller end thereof and acts upon said roller. When the device handle is moved from the operating (diagonal) positional thereof towards said rest position thereof said link and guide pushes down upon said thrust roller causing the body of the device along with the brushes to move upwards and away from the floor. In the opposite movement of said handle, the restraint and thrust applied upon said thrust roller during the former handle movement is not present At this point, under the effect of the weight thereof, said device body and brushes move down towards the floor while said rollers retract upwards. Said linkage is an assembly of levers and connecting members and said link and guide arrangement. Different configurations of said linkage are conceivable and are within the scope of the invention. The drum of the invention is a cylindrical member of composite construction. The base drum, that is, the inner layer of the drum is of PVC and is of moulded construction. The outer layer, that is, the coating thereupon may be of any suitable plastics or elastomeric composition that resists wear, abrasion and does not swell in the wash waters that are encountered in industrial applications of the device. Preferably said outer layer is of nitrile rubber or a mixture of neoprene and nitrile rubber. More preferably, the material of construction of said outer layer is nitrite mbber. Said outer layer of nitrite rubber is mounted onto said PVC base drum by a process similar to shrink fitting. Other material for said base drum such as chlorinated polyvinyl chloride and for said outer layer and other fabrication methods for said base drum and outer layer are within the scope of the invention. Various methods are available in the art for application of said outer layer on the inner one. Said drum is provided with a suitable saaper that directs/deflects said wash water from the drum surt'ace into said collection tank. The device motor is housed inside said drum. The side housing closest to the terminals of the drive motor houses the electricals of the device. Said electricals comprising circuits and components such as circuit breakers, switches are provided on a modular boxed panel that is made splash proof. Said boxed panel is housed in one said side housing. The power cable (running cable) of the device connects to said modular panel without being routed first to the isolation switch in the top part: of the device handle as in the prior art device. For mounting and stowing away said power cable when the device is not in use the device of the invention comprises brackets/hooks having spring-loaded swing arms, around which said cable is coiled away. Said spring-loaded swing arms allow easy and quick removal of said cable coil unlike in the prior art device. Said roller-carrying arms and the extensions thereof have been mentioned hereinabove. Retraction of said rollers brings the pair of said extensions on each side of the device closer to each other and vice versa. The said retraction prevention means of the invention is based on the novel idea of preventing said dosing-in when the retraction of said rollers is to be prevented. This is achieved in the device of the invention by the interposition of a spacer member of appropriate length between a said extension pair when said device handle is required to be moved into the diagonal positions thereof for the purpose of said transport of the device. The presence of said spacer niember prevents said closing-in and therefore said retraction. Said spacer member (spacer piece) is mounted on one side of the device or both. It is movable up and down and comprises a pedal portion that is operable by foot. Said spacer member is normally in position such that movement of the device handle will not retract said rollers or switch on the device motor. To get the device into the operation mode thereof said spacer piece is moved away from between said pair of extensions by operating said foot pedal portion thereof. Other configurations of said spacer member, such as for example, a pivoted arrangement are within the scope of the invention. It may also comprise a linkage that allows it to be operated for example, at the level of the top of the said handle. Said retraction prevention means includes a detent means (spring-loaded locking means) that stabilises said spacer piece in the two positions thereof and ensures that said spacer piece does not inadvertently slide out of said positions. It will be observed that the degree of said dosing-in is proportional to the amount of said retraction. The latter in turn, detemnines the amount of said lowering of the brushes, that is, the degree of the brush contact with the floor. Thus, different extents of said brush contact can be obtained by regulating the degree of said closing-in. This is the basis of the brush wear compensation means of the invention. Said regulation is achieved by providing a stepped spacer member (stepped spacer piece), which comprises a series of spacer elements of different lengths. Said closing-in is controlled to the desired degree by interposing the appropriate said spacer element therel^etween. In the device of the invention said * stepped spacer member is slidable up and down and is located on one side of the device between the pair of said extensions on that side. It comprises spring-loaded position-locking arrangement (detent means). Other configurations of said stepped spacer member, other movement system for said means and other said locking arrangement thereof are within the scope of the invention. Said means may also be provided on both sides of the device. To compensate for said brush wear, said means is operated such that a shorter spacer element is interposed between said extension pair. This increases said retraction and said lowering of the brushes. This novel means is unlike as in the prior art device. As mentioned hereinabove, said brush wear compensation means also serves as brush pressure control means. Different values of the brush pressure on the floor can be obtained using the different settings of said brush wear compensation means. Said roller-carrying arms in the device of the invention are of substantially solid construction and have a width that is somewhat large than the width of the rollers. The said geared portions thereof are consequently considerably wider than that found in the plate-based roller carrying arms of the prior art device. This gives smoother, less noisier and misalignment-free operation of said geared portions in the device of the invention. The device comprises four said rollers carried on two said transverse shafts thereof. Said rollers are mutually linked dynamically through said geared portions and the shafts thereof. Said rollers are of dual-moulded construction comprising radially inner and outer portions, the former being of a low-friction plastics material such as for example, nylon or teflon while the latter is of a plastics such as polyurethane that withstands wear, abrasion and the aggressive wash waters that may arise in industrial environments. Preferably the material of construction of said inner and outer layers are nylon and polyurethane respectively. Within the scope of the invention, said rollers may be of metallic materials or additionally of non-metallic materials other than plastics. A wide range of fabrication methods for attaching said Inner and outer layers are available and are within the scope of the invention. Unlike in the prior art device, a spring is mounted between a said pair of extensions on one side of the device. Said spring ensures that said retraction occurs to the maximum possible extent that is, to the limit (stop) thereof set by said brush wear compensation means. Said limit is determined by which said stepped spacer element has been interposed between the said pair of extensions. In the transport mode of the device, of course, the spacer piece interposed between said pair of extensions is of such a size that said retraction is substantially totally prevented. Brush alignment means is provided in the device of the invention so as to make the removal and re-installation of brushes easier and quicker than is the case in the prior art device. As mentioned hereinabove, said means comprises support brackets (ledges, lips) that extend from said side housings towards said longitudinal axis of the device. Said brackets are arcuate in shape and are positioned such that when a brush is placed on a pair of said corresponding brackets, said brush is substantially aligned with respect to the bearings thereof. In the said aligned position, sliding in said brush shaft into said bearings thereof and the said hollow of the brushes is a simple and quick operation. For ease of assembly chamfers are provided on the ends of said shafts and at the entrances of said bearing portions. Said arcuate supports may be circular or otherwise. In the device of the invention they are substantially semi-circular in shape. Other configurations of said brackets such as a V-shape are also within the scope of the invention. The said auxiliar/ tank in the device of the invention is of plastics and holds water or other cleaning fluid. Said tank is mounted on the said handle of the device by snap-fit arrangement which permits easy removal and re-mounting thereof. It is a stand-alone type tank unlike in the prior art device. To prevent accidental coming off of the tank, said brackets having spring-loaded swing arms are provided that allow easy removal and re-mounting of the tank. The auxiliary tank of the invention is a dual function tank that can be used either as a reserve tank as in the case of the auxiliary tank of prior art or in a dual-feed mode wherein liquids from both said water and auxiliary tanks are simultaneously fed to the floor during operation of the device. In the reserve mode, the auxiliary tank of the invention supplies water (or other fluid) to said distribution chamber when said water tank of the device has run dry. In said dual-feed mode the fluid from said auxiliary tank flows into said storage section of the water tank, mixes with the fluid contained therein and the fluid mixture flows out into said discharge chamber and from there onto the floor below through the series of discharge holes provided therein. Thus, the auxiliary tank of the invention can be used, for example, to add a detergent liquid to the water coming from said water tank. Other materials of construction and other configurations for said auxiliary tank are within the scope of the invention. As in the prior art device, the starting of the device motor in the device of the invention is linked to the movement of said device handle. The inter-connection is through said mechanical linkage such that when said handle is moved towards the operating positions thereof the device motor is switched on. However, the nature of said inter-connection (linkage) in the device of the invention is novel and functionally better than in the prior art device. In the device of the invention, a small extension is provided on said roller-carrying arm of said thrust roller. Said small extension is located on said arm on the same side as the roller unlike in the case of said extension pairs that are located on the opposite side. When the device handle is moved towards the operational positions thereof said small extension engages with the operating arm of said motor switch causing the switch to close and start the device motor. When the said device handle is moved towards the operational positions thereof during the transport mode, the closing of said switch needs to be prevented. This is done by activation of said retraction prevention means. It will be clear that said engagement of the arm and small extension can only occur when said rollers retract, so by preventing said roller retraction the closing of the said switch is also prevented in said transport mode. It will be noted that when said retraction prevention means is not activated an inadvertent movement of said device handle will switch on the device motor. This is also the case in the prior art device and is not desirable from the point of view of safety. In the prior art device, this aspect has been taken care of by the provisiori of an isolation switch located at the top of the device handle. As mentioned hereinabove, such an isolation switch has been eliminated in the device of the invention for safety reasons. The device of the invention provides for a mechanical arrangement for prevention of said inadvertent starting of the device motor. Said mechanical arrangement consists of automatically locking said device handle each time It is returned to the rest position thereof. Once it is locked it cannot be moved to a said operational position unless and until said lock is opened. Said lock comprises a spring-loaded snap-action lever that locks onto said link and guide arrangement when said device handle returns to the rest position thereof. Said lever comprises a pedal portion that is foot-operated. The operator has therefore to compulsorily operate said foot pedal so as to release said device handle which only then can be moved to an operational position. The device of the invention is suitable and is adapted for cleaning of a large range of floors (surfaces) such as, for example, marble, granite, cement, vinyl and others. In order to provide a clearer understanding of the invention and without limitation to the scope of the invention, an embodiment thereof will now be described with reference to the accompanying drawing wherein like numerals represent like parts and wherein, Fig. 1 shows the front view of the device of the invention; Fig. 2 shows another front view of the device of the invention; Fig. 3 shows the idle and operating positions of the operating handle of the device of the invention; Fig. 4 shows the operation of the brushes and drum of the device of the invention; Fig. 5 shows the front and a side view of the auxiliary tank of the device of the invention; Fig. 6 shows a part of the drive system of the device of the invention; Fig. 7 shows another part of the drive system of the device of the invention; Fig. 8 shows the roller retraction mechanism of the device of the invention; Fig. 9 shows the modular panel of the device of the invention; Fig. 10 shows the retraction prevention means of the device of the invention; Fig. 11 shows the brush pressure control means of the device of the invention; Fig. 12 shows the brush alignment means of the device of the invention; Fig. 13 shows the mounting of the motor and the cooling/ventilating means for the motor in the device of the invention; Fig. 14 shows the power cable stowing arrangement in the device of the invention; Fig. 15 shows a cross sectional view of the device of the invention; Fig. 16 shows another view of the auxiliary tank in the device of the invention; Fig. 17 shows a cross sectional view of the water tank and water tank discharge valve in the device of the invention; Fig. 18 shows cross section of the drum of the invention; Fig. 19 shows the operational arrangement of the water discharge valve in the device of the invention; Fig. 20 shows a section through a roller of the device of the invention; Fig. 21 shows the brush mounting in the device of the invention; Fig. 22 shows the ventilation arrangement for the motor in the device of the invention; Fig. 23 shows the construction of the brushes in the device of the invention; and Fig. 24 shows the arrangement of cleaning fluid discharge in the device of the invention. Reference numeral (1) of Fig. 1 denotes the body (housing) of the device wherein the fore brush (2) and aft brush (3) are mounted, the former being forward of, and latter rearward of the drum (4) of the device. Said housing (1) is of an aluminium alloy construction and further comprises the left side housing (5) and right side housing (6). The device-operating handle (7) is a generally U-shaped member mainly fabricated from pipe material and comprises a top portion (8) that is held/gripped by the operator during operation of the device and left and right side arms (9,10) respectively. Said arms are pivotally mounted on housing (1) and are rotatably rigid with the pivot shaft (11) thereof. This allows movement of said handle (7) in the vertical plane from the rest (idle) position (12) thereof to an operating position (13) thereof. As will be observed from the figures said handle (7) is substantially vertical in the rest position (12) thereof and in diagonal (inclined) orientation in the operational positions thereof. Any of the said diagonal positions can be used in operation of the device the choice being with the operator as to which of said positions is most ergonomically convenient to him. The mounting of handle (7) is in the middle region of housing (1). Forward of handle (7) on the body is located the water tank (14) and rearward is the collection tank (15). The two tanks (14,15) are of plastics construction and are mounted on body (1). Said tanks can be easily lifted off the device body when access to said brushes (2,3) is desired although removal of said tanks is not necessary for removal of said brushes for cleaning and/or replacement. Said tanks (14, 15) have lids (89,90) and their mounting is such that removal of said tanks for cleaning and/or re-filllng and re-installation thereof on the body (1) is an easy and quick operation. Tank (14) holds water (or other fluid) for floor cleaning and feeds water to a discharge chamber (16) located below the storage section (17) of said tank. Brushes (2,3) are counter-rotating such that during operation they direct/throw said wash water towards rotatable drum (4). Said wash water carried by drum (4) is directed/deflected by scraper (18) into said collection tank (15). Said wash water is the mixture of water and/or other detergent liquid together with the solid and liquid mdtter coming from the cleaning of the floor. Wash water collected in collection tank (15) is periodically drained out. Auxiliary tank (19) is mounted on handle (7) by a snap-fit type of arrangement (20). It is further held by brackets (21) having spring-loaded swing arms (22) that permit easy and quick detachment and attachment of tank (21) on handle (7). Tank (21) comprises valve (23) located at the bottom thereof and is connected to said discharge chamber (16) by means of flexible tube/hose (24) which connects to connection piece (25) of the water tank discharge valve (36) of the water tank (14). Between storage part (17) and discharge chamber (16) of water tank (14) is provided water tank discharge valve (26) located on the floor of storage section (17). Connection piece (25) is connected to said water tank discharge valve (26), such that when said valve is opened fluid from auxiliary tank (19) flows into said storage section (17) mixes with the fluid therein and the mixture of fluids flow out through said valve (26) into said discharge chamber (16) below. From the discharge chamber (16) the fluid mixture flows out onto the floor below through perforations (27) provided therein. It will be clear that auxiliary tank (19) can be used in the twin-fluid mode as described hereinbefore and also as a reserve tank to supply to discharge chamber (16) when water tank (14) runs dry. To prevent accidental detachment of auxiliary tank (19) brackets (21) are provided. Said brackets (21) have spring-loaded swing-arms (22) that can be swung away to one side when It is required to take out tank (19) for cleaning and/or refilling. The arrangement of said swing arms (22) makes the removal and re-installation of tank (19) simple and quick. Drum (4) comprises the inner layer made of PVC (30) over which the wear and abrasion and swelling resistant outer layer (31) of nitrile rubber has been applied by a process similar to shrink fitting. Drive motor (32) is housed within drum (4). The drive system consists of pinion (33) mounted on motor shaft (34). Pinion (33) drives one of two coupled helical gears (35,36) that are, in turn, coupled to cogged wheels (37,38) referred to as fore and aft cogged driver wheels. Cogged driver wheels (37,38) are coupled to cogged driven wheels (39,40) by means of cogged belts (41,42). Thus, there are two cogged belt drives one for the fore brush (2) and the other for the aft brush (3), said cogged driven wheels being mounted on the brush shafts (43,44) of the brushes (2,3) respectively. Both cogged belt drives include tensioner wheels (45,46). The aft cogged belt drive (42) further includes a cogged wheel (47) that drives drum (4) through a toothed pinion (54) that is on a common shaft with cogged wheel (47). Pinion (54) engages with the teeth provided on the inside of drum (4) at one end thereof and provides drive thereto. Both coggod bolt drives IftGiudo tcnsionor wheels (15,16). Said mechanical linl It Includes said link and guide arrangement (51) that transmits thrust to said roller arm (49) when the handle (7) Is moved to the Idle position (12) thereof. When handle (7) moves away from the idle position (12) towards an operating position (13) thereof the restraint provided by the said linl Mechanical linkage (48) operates motor switch (52) through the small extension (53) on roller arm (49) of thrust roller (50). The retracting thrust roller (50), through the small extension (53) thereof engages with ann (55) of motor switch (52). This action closes the switch and starts the device motor (32). The device comprises four said rollers in all: said thrust roller (50) and further three rollers (56). They are mounted one each on roller carrying arms (49, 57) that engage with two hexagonal-sectioned transverse shafts (58, 59). Said arms (49,57) comprise geared portions (60) that engage with each other on the two sides of the device. Said geared portions (60) and shafts (58,59) constitute the dynamic linkage between the four rollers (50,56). Each roller carrying arm (49,57) has an extension (61) located on the other side of the geared portion (60) thereof such that the device comprise a pair of said extensions (61) on each side thereof. A said pair of extensions (61) together with the arm portions (49,57) and geared portions (60) thereof are in the general configuration of a pair of scissors, the fulcrum thereof being located on said geared portions (60). When rollers (50,56) are retracted, said pairs of extensions (61) on each side of the device close-in on each other. In the device of the invention, said retraction is prevented when desired by the interposition of a spacer member (spacer piece) (63) between a pair of said extensions (61), Said spacer member (63) constitutes the retraction prevention means (62) of the device of the invention and further comprises pedal portion (65) thereof. Said pedal portion (65) is under spring bias provided by spring detent means (64). Said means (62) is movable up and down and is brought down by activating the foot operated pedal portion (65). On operation of pedal (65) spacer piece (63) is slid into position between the pair of extensions (61). Means (62) is activated when handle (7) is required to be moved to an operating position for the purposes of transporting the device as opposed to operating the device for the purpose of floor cleaning. It will be noted that it is important to have the said rollers down (descended) during said transport of the device and for this purpose said means (62) is activated. The greater the said roller retraction, the greater said lowering of brushes (2,3). When brushes wear off it is desirable to increase said lowering so as to maintain adequate brush contact and pressure on the floor. The brush wear compensation means (66) of the Invention provide said Increased lowering to compensate for said wear. I^eans (66) is based on Increasing said retraction that automatically increases said lowering. Said means (66) comprise a stepped spacer member (67) that is interposed between a pair of said extensions (61). Said stepped spacer piece (67) comprises a series of spacer elements (68) and is movable vertically up and down between said pair of extensions such that the desired said spacer element (68) may be brought in position and interposed between said pair of extensions (61), Said retraction Is substantially nil In the said transport mode of the device. In the operation mode of the device said retraction would be corresponding to the particular said stop (limit) selected such as either to provide the desired brush pressure or to compensate the brush wear. The length of the spacer piece (63) determines the said maximum value of retraction. The lengths of said spacer elements (68) are designed to provide a series of convenient intermediate magnitudes of said retraction and through that of said brush lowering. Said means (66) comprise a handle portion (69) by means of which it is moved up or down and spring-loaded detent means (70) that provide firm holding of the means (66) in the different positions thereof. With increasing brush, wear said retraction setting is raised by moving into place a smaller said spacer element (68) between said pair of extensions (61). The device comprises a safety lock means (71) the purpose whereof is to lock said handle (7) in the rest position thereof each time the handle (7) is brought to said rest position. This Is to prevent accidental or inadvertent lowering of said handle (7) from the rest position (12) thereof and the consequent inadvertent starting of the device motor (32). Safety lock (71) must be necessarily de-activated for operating the handle (7) for moving it into the operational positions thereof. Said handle (7) cannot be moved unless and until said safely lock (71) is opened. Means (71) comprises a spring-loaded, foot-operated lever that snap-locks onto said mechanical linkage when the handle (7) returns to the vertical (idle) position (12) thereof. Said snap locking occurs at a point on said link and guide (51). Locking of said link and guide (51) immobilises the entire mechanical linkage (48) and along with it said handle (7) and the retraction system. Means (71) comprises a pedal portion (73) that is operable by foot. When it is required to operate the device again in the operation or transport modes the mechanical linkage (48) is unlocked by depressing said pedal portion (73). Brush alignment means (74) of the device make the operation of removal of said brushes (2,3) for cleaning and/or replacement easier, simpler and quicker. Means (74) comprise arcuate brush supports (75) located on said side housings (5,6). Each brush (2,3) is provided with said support (75) on both sides thereof. Supports (75) are accurately positioned such that when a brush is placed on them, the shaft hole (76) is in proper alignment with the bearings (77,78) thereof. Said brackets (supports) (75) are generally semi-circular in the device of the invention. Further, chamfers are provided on the ends of the brush shafts and at the entrances to said brush bearings (77,78). Said chamfers make the assembly of shaft and brushes onto the device further easier. Other shapes and configurations thereof are within the scope of the invention. Once said shaft hole (76) and bearings (77,78) are in alignment the sliding of the brush shaft is an easy and quick operation. Brushes (2,3) comprise tubular core portions (tubular members) (81,82) that are generally hollow, cylindrical in configuration, the shafts (43,44) thereof being mounted in said hollows (76) thereof. The brush shafts in the device of the invention are hexagonal in section and engage with similar hexagonal portions in said hollows. The brush bristles (83) are located on said tubular core portions (81,82). Said brush shafts have spring-loaded balls at their ends that lock the shafts in position. The electrical system of the device comprises the modular panel (84) whereupon are mounted the electrical components and the circuits thereof. Said modular panel is of the box type and is novel. It comprises the switches, circuit breakers, connectors and other components of the electrical circuitry of the device. Said boxed modular panel is made splash proof. For proper ventilation/cooling of the device motor (32) housed within drum (4), air inlet openings (85) and air outlet openings (86) are provided on the outer and inner walls of the side housings (5,6) that provide adequate passage for ventilating air from one side of the device to the other through the drum interior. The location of said openings (85,86) is such as to prevent/minimise ingress of wash water droplets Into the drum interior and further suitable griHes/baffles (79,80) are provided In said openings to stop such droplets from entering the drum interior. This is unlike as in the prior art device. Said water discharge valve (26) of water tank (14) is operated by the valve-operating handle (87) located at the top part (8) of handle (7). Valve handle (87) operates through a bowden cable (88). Rollers (50,56) are rotatably mounted one each on the ends of the roller-carrying arms (49,57). Each said arm (49,57) engages with an end of the roller shafts (58,59). Shafts (58,59) are hexagonal in section and their hexagonal ends engage with hexagonal shaft holes in said arms (49,57). Rollers (50,56) are of dual moulded construction and are of plastics. Each roller (50,56) comprises an inner portion (91) and an outer portion (92). The inner portion (91) is a Molybdenum Disulphlde impregnated nylon moulding which is a low-friction plastic while the outer portion (92) is of polyurethane which provides wear and abrasion resistance and further is resistant to swelling by wash water. Polyurethane also does not leave smear marics on the floor during operation of the device. Each roller (50,56) is provided with two skJe covers (93) that prevent Ingress of dirt or wash water into the axle region thereof. Preferably said outer portions are of Bayer make polyurethar^ grades TPU 392 or TPU 385 or equivalent. More preferably they are of TPU 392 or equivalent The device of the invention is provided with brackets (28) on handle (7) around which the power (running) cable (95) thereof may be coiled around when the device Is not in use. Brackets (28) have said spring-loaded swing arms (29) that allow easy removal of the cable coil. Said brackets are novel. A bottom cover (96) located underneath housing (1) covers the region between the brushes (2,3) and prevents ingress of wash water or other foreign matter there from into tfie drum (4). To operate the device, the power cable (95) is removed from brackets (28) by turning away said swing arms (29) of said brackets (28) and connected to a wall socket or other source of power. Said safety lock (71) on the link and guide (51) is then released by operation of the foot pedal (73) of the safety-locking lever (72). The retraction prevention means (62) is de-activated by operating the pedal portion (65) thereof. The device is now ready to be started and this is done by movement of handle (7) into a diagonal position (13). Movement of handle (7) causes the closing of the motor switch (52). This occurs because when the rollers (50,56) retract upon said movement of handle (7) the small extension (53) of the thrust roller (50) engages with the operating arm (55) of the motor switch (52) causing it to dose. TTils starts the device motor (32). As the rollers (50,56) are retracted the device rests on the rotating brushes (2,3). At this point, water discharge to the floor is started by opening water discharge valve (26) by means of remote operating handle (87) thereof. The device is now ready for operation and is pushed along on the floor to carry out floor cleaning. Said wash water arising out of the washing/scrubbing of the floor Is thrown by said counter-rotating brushes onto the rotating drum (4) which carries it round to where the scraper (18) thereof is located. Scraper (18) directs/deflects the wash water off the drum surface into the collection tank (15). For transporting the device, said safety lock (71) is first released. The roller retraction prevention means (62) is always kept in the activated position when the device is returned to the idle state thereof. Handle (7) is then brought down into the diagonal orientation (13). It will be noted that the device, at this stage, is resting on the rollers (50,56) thereof and can be conveniently rolled/pushed along on said rollers to the desired location for operation there or for storage. As said rollers (50,56) have not been retracted the brushes (2,3) of the device are above the floor in their raised position. Removal of water and collection tanks (14,15) for cleaning and/or refilling is simple as said tanks are not fastened to body (1) of the device. A said tank (14,15) is just lifted off its position on the body (1). The lid tiiereof is opened and the tank emptied and/or cleaned and/or refilled as required and put back. Said water tank discharge valve (26) comprises a spring-loaded spindle (97) that automatically springs back into the closed position thereof when the valve-operating handle (87) thereof is released by the operator. For removal of brushes (2,3), said tanks (14,15) may be removed to uncover the brushes although it may be stressed that said brushes are easily removable even while said tanks (14,15) are in position on the device body (1). The shaft to be removed is given a slight push sideways from one side of the device through the access hole (94,98) provided in the side housing. This causes the other end thereof to emerge at the other side of the device through a similar access hole (94,98) provided in that side housing. The emerged end is gripped by hand and the shaft pulled out from that end quickly and effortlessly. The brush now comes to rest on the brackets (supports) (75) thereof and is lifted out for maintenance or replacement or for change of brushes. The re-assembly procedure should be quite clear from the above. For removal of the auxiliary tank (19), the hose connection (24) thereof to said water discharge valve (26) is first disconnected and then the swing arms (22) of the tank retaining brackets (21) are then turned away. The tank is then easily pulled out of the snap engagement (20) thereof on the handle (7), It may be cleaned and/or refilled as necessary and put back by exactly the opposite procedure to that described above. Various embodiments and variations other than the above that are within the art are within the scope and spirit of the invention. I claim: 1 A floor-cleaning device that comprises, a pair of counter-rotating brushes located fore and aft of a rotatable drum that during operation throw/direct the wash water arising from said floor cleaning onto said drum; a water tank that discharges water onto said floor for cleaning thereof; a collection tank wherein said wash water is collected, said wash water being deflected/directed thereinto by a scraper engaging with said drum; a set of rollers/wheels on which the device is moved/rolled along during transport thereof from location to location and that, when the device is to be operated, are retracted such as to cause lowering of said brushes into contact with the floor, each said roller being rotatably mounted at the end of a roller-carrying arm; a pair of transverse shafts, the ends thereof being in engagement with said arms; geared engagement between the pair of said arms on both sides of the device through geared portions provided thereon resulting in a dynamic linkage between all four said rollers; extensions on the pair of said arms located on one or both side of the device,said pair(s) of extensions closing-in towards each other during said retraction; i. a generally-U-shaped operating handle mounted on the body (housing) of the device and pivotable between a vertical orientation (idle position) thereof to a diagonal orientation (working position) thereof for pushing the device during operation or during the said transport thereof; a mechanical linkage containing inter alia a link and guide connecting said handle and a said roller such that said rollers are retracted upon movement of said handle into a working position thereof; a retraction prevention means for preventing said retraction when the movement of said handle into a said working position thereof is required for the purpose of said transport; a brush wear compensation means that provides increased lowering of the said brushes such as to compensate for the wear thereof or otherwise to provide increased brush pressure on the floor; a drive system linking the electric motor (prime mover) of the device with said rotatable drum and brushes, the device being with or without said prime mover thereof; and optionally an auxiliary tank for holding water or other cleaning fluid; and wherein said drum is of a composite construction. The floor cleaning device as claimed in the preceding claim 1 wherein said drum is of plastics construction, the outer cylindrical portion thereof being of wear, swelling and abrasion resistant material while the inner cylindrical portion thereof being of a material that provides strength and rigidity to the drum. The floor cleaning device as claimed in the preceding claim 2 wherein said inner and outer cylindrical portions are of a material selected from PVC (polyvinyl chloride), and cPVC (chlorinated poly^/inyl chloride) and from neoprene, nitrile rubber and neoprene-nitrile rubber mixtures respectively. The floor-deaning device' as claimed in the preceding claim 3 wherein said inner and outer cylindrical portions are of PVC and nitrile rubber respectively. The floor cleaning device as claimed In any of the preceding claims 1 to 4 wherein said retraction prevention means comprises a spacer member that is interposable between a pair of said extensions such as to prevent said closing-in thereof, said spacer member being provided on either or both sides of the device and comprising a foot-operated pedal part for operation of said means. The floor cleaning device as claimed in any of the preceding claims 1 to 5 wherein said brush wear compensation means (brush pressure control means) comprises a spacer member of stepped construction that is movable up and down such that the desired step thereof can be interposed between a said pair of extensions such as to control the extent of said closing-in, and therefore, said lowering of brushes and said brush pressure. The floor-cleaning device as claimed in any of the preceding claims 1 to 6 wherein said drive system comprises cogged wheel drives, one whereof extending from said motor to said fore brush and the other to said drum and aft brush. The floor-cleaning device as claimed in any of the preceding claims 1 to 7 wherein said optional auxiliary tank is of the freestanding type and is mounted on said handle by means of a snap-fitting arrangement. The floor cleaning device as claimed in the preceding claim 8 wherein brackets having spring-loaded swing arms are provided on said handle for retaining said auxiliary tank and for the easy attachment and detachment thereof. The floor cleaning device as claimed in any of preceding claims 1 to 9 wherein the water discharge valve of said water tank is of the dual-purpose type which upon opening allows simultaneous flow of fluid from said auxiliary tank into the storage section of said water tank and of the fluid mixture from said storage section to the floor through the discharge chamber of said water tank. The floor cleaning device as claimed in any of the preceding claim 1 to 10 further comprising a safety locking means for said handle in the said idle position thereof said means comprising a spring-loaded foot-operated snap-action lever that engages with, and locks said link and guide in the idle position thereof. The floor cleaning device as claimed in any of the preceding claims 1 to 11 further comprising brush aligning means that allow easy removal and mounting of said brushes on the device, said means comprising arcuate brackets (lips, ledges) positioned such that a brush placed upon a pair of corresponding said brackets would be in substantial alignment with the bearings thereof permitting the shaft thereof to be easily and conveniently slid into the shaft cavity (hollow) thereof and into said bearings thereof. The floor-cleaning device as claimed in any of the preceding claims 1 to 12 wherein the water tank discharge valve of said water tank is remotely operated from the top part of said device handle by means of a bowden cable. TTie floor-cleaning device as claimed in any of the preceding claims 1 to 13 wherein the electrical circuits and components thereof are housed in a splash-proof boxed modular panel that is housed in a side housing of the device. The floor cleaning device as claimed in any of the preceding claims 1 to 14 wherein means are provided on said device handle for coiling the power cable (running cable) thereof when not in use, said means comprising said spring-loaded swing-arm type bradcets. The floor cleaning device as claimed in any of the preceding claims 1 to 15 wherein said rollers are of dual moulded plasties construction, the radially inner and outer portions thereof being respectively of low-friction plastics and of wear-, abrasion and corrosion resistant plastics that do not smear the floor. The floor-cleaning device as claimed in the preceding claim 16 wherein said inner and outer portions are of materials selected from Nylon, and Teflon and of polyurethane respectively. The floor-cleaning device as claimed in the preceding claim 17 wherein said inner and outer portions are of molybdenum disulphide impregnated nylon and a Bayer grade TPU 392 polyurethane or equivalent respectively. The floor cleaning device as claimed in any of the preceding claims 1 to 18 wherein said pair of extensions on one or both said sides are spring-loaded such as to prevent the idling contact of said rollers on the floor during operation of the device. A floor-cleaning device substantially as herein described with reference to and as illustrated in the accompanying drawings.

Documents:

081-che-2004-abstract.pdf

081-che-2004-claims duplicate.pdf

081-che-2004-claims original.pdf

081-che-2004-correspondnece-others.pdf

081-che-2004-correspondnece-po.pdf

081-che-2004-description(complete) duplicate.pdf

081-che-2004-description(complete) original.pdf

081-che-2004-drawings.pdf

081-che-2004-form 1.pdf

081-che-2004-form 19.pdf

081-che-2004-form 26.pdf