| Title of Invention | WHEEL FOR DRIVING A FLEXIBLE HANDRAIL |
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| Abstract | Wheel (10) for driving a flexible handrail of an escalator or moving walk. The wheel (10) can be turned about an axis of rotation and has a readily elastically deformable layer (30). The readily elastically deformable layer (30) is formed by a body that in itself is stable in form when it is free of stress. Arranged adjacent to an inner circumbferential surface (31) of the readily elastically deformable layer (30) is an inner layer (20) that is stiffer that the readily elastically deformable layer (30). Adjacent to an outer circumferential is an outer layer (40) that is intended to rest against the handrail under static firction. Respective adjacent layers (20, 30, or 30, 40) are coupled to each other in non-rotating manner. |
| Full Text | Wheel for Driving a Flexible Handrail The invention relates to a wheel for driving a flexible handrail of an escalator or moving walk according to Claim 1. Escalators and moving walks generally have balustrades that are locationally fixed at their sides. Mounted on or against the balustrades are band-shaped handrails that move relative to the balustrades as synchronously as possible with the step elements of the escalator or moving walk. The handrails consist essentially of a flexible band and can be driven by a wheel that can itself be driven directly or indirectly by a motor. At the same time, this wheel can also serve the function of a diverter sheave to divert the handrail where a change of direction of the handrail is required. The drive of handrails should be as continuous as possible, free of jerk, and as quiet as possible, and the wheel as well as the handrail itself should be executed in such manner that noise and wear are minimized. In particular, so-called slip-stick effects should be avoided. Slip-stick effects are instability effects associated with parameters which affect the static friction and sliding friction between the handrail and the contact surface of the wheel that drives the handrail To realize a continuous drive of the handrail, sliding of the handrail relative to the wheel should be avoided, which means that the static friction should not fall below a certain amount. In practice, however, it is common for brief periods of sliding friction to occur, which is comparable to aquaplaning and results in the said slip-stick effect. To prevent slip-stick effects, a known wheel for driving a handrail was executed in such manner that it is formed essentially as a readily elastically deformable layer in the form of a driving-wheel tire. This driving-wheel tire is filled with a filling agent such as compressed air or an inert gas. The driving-wheel tire acts as a power transmission element in that its outer circumferential surface rests under pressure against the inner surface of the handrail so that on rotation of the driving-wheel tire the handrail is driven by the static friction acting between the power transmission element and the handrail. Disadvantageous with this driving wheel is, among others, the formation of bulges on the driving-wheel tire, which occurs as a consequence of its elasticity, the substantial wear, the production of noise, and the risk of damage especially of the gas-filled driving-wheel tire. The objective of the invention is to propose a wheel for driving a flexible handrail of an escalator or moving walk with which the disadvantages of the prior art are avoided. The objective is fulfilled according to the invention by the characteristics of the characterizing part of Claim 1. Preferred embodiments of the wheel according to the invention are described in the dependent claims. Important advantages of the new wheel are prevention of the slip-stick effect between the wheel and the handrail and prevention of the formation of bulges in the contact area of the wheel and handrail. The slip-stick effect is essentially determined by the ratio of static friction and sliding friction between the outer circumferential surface of the tire cover and the handrail against which it is pressed by gas pressure. The type of friction essentially depends firstly on the coefficients of static and sliding friction between the materials of the tire cover and the handrail which are themselves affected by their surface structure and surface roughness; secondly, on the pressure under which the tire cover rests against the handrail; and thirdly, on the extent of the contact surface between the tire cover and the handrail. The formation of bulges essentially depends on the respective rigidity of the material as well as the thickness of the material since, depending on these, bulges form between the tire cover and the handrail both in, and perpendicular to, the direction of motion that result in vibrations that cause noise and cause wear. If the slip-stick effect is prevented, the creation of noise is prevented to the extent that it depends on the energy that is freed on transition from static friction to sliding friction. If the formation of bulges is prevented, the creation of noise is reduced to the extent that it depends on the said vibrations. At the same time, wear of the respective components and the power required for driving are reduced, while the ride comfort is increased. Whereas the aforesaid conventional wheel for driving a flexible handrail has as readily elastically deformable layer a tire cover filled with pressurized gas, in the wheel according to the invention the readily elastically deformable layer is formed by a body made from a solid material that in itself, for example without the effect of pressurized gas, is stable in form and readily elastically deformable. Arranged adjacent to an inner circumferential surface of this readily elastically deformable layer or intermediate layer is an inner layer that is stiffer than the readily elastically deformable layer. The inner layer generally directly adjoins the intermediate layer and is non-rotatably connected to the intermediate layer. Arranged adjacent to an outer circumferential surface of the readily elastically deformable layer or intermediate layer is an outer layer that is intended to rest under sufficient pressure against the handrail that is to be driven. The outer layer generally directly adjoins the intermediate layer and is non-rotatably connected to the intermediate layer. The intermediate layer stretches the outer layer onto the handrail in such manner that when the wheel is driven, a frictional engagement occurs between the outer layer and the surface of the handrail with which it is in contact, which has the consequence that the rotation of the wheel is transformed into the movement of the handrail. The inner layer can be connected to a rim body of the wheel or form an integral component of such a rim body. The solid body that forms the elastically readily deformable layer is preferably a body that is least approximately a hollow cylinder. This body can have recesses to facilitate its elastic deformability. The recesses can communicate with the outside of the layer or be enclosed within it. It is, however, also possible for an elastically readily deformable band to serve as intermediate layer. In this case, the band is laid or arranged around the inner layer (e.g. a rim body) and then forms a body like a hollow cylinder. The outer layer, which is elastically relatively flexible, preferably has a stiffening. This stiffening can be integrated in the outer layer or form a sub-layer that is arranged adjacent to the outer layer. The stiffening effect can he created with stiffening elements, for example elongated stiff elements in wire or mesh formation. Possible materials for execution of the stiffening are metal and/or natural fibers and/or plastics. The outer layer usually has on its outer circumferential surface a structure. A structure with grooves running in the direction of the circumference (lengthwise grooves) allows water to flow off that can penetrate through the handrail in the area of contact of the handrail and the outer layer. Other structures can serve to improve the above mentioned frictional engagement. It is preferable for the wheel to be driven by a lantern pinion wheel such as was shown in EP1464609. The lantern pinion wheel engages in the step chain and turns the wheel which comes into contact with the handrail either on the upper surface or the lower surface of the handrail and moves the handrail. Alternatively, the wheel can also be driven by a conventional handrail drive unit such as, for example, a friction wheel. Further characteristics and advantages of the wheel according to the invention are explained below in relation to exemplary embodiments and by reference to the drawings. Shown are in Fig. 1 a moving walk or escalator with a handrail that can be driven by means of a wheel according to the invention, in part, in a highly simplified representation, from the side; Fig. 2 a first wheel according to the invention, in part, in a diagrammatical representation; Fig. 3 a second wheel according to the invention, in part, in a diagrammatical representation; and in Fig. 4 a third wheel according to the invention, in part, in a diagrammatical representation. Identical and similar, or identically functioning, components of the various embodiments of the new wheel are referenced by the same numbers in figures 2, 3, and 4. Fig. 1 shows a wheel 10 according to the invention that can be turned about an axis of rotation A and drives a handrail 11. The handrail 11 is located on the upper edge of a balustrade 12 that is arranged at the side of not-shown step elements of the escalator or moving walk. The handrail 11 lies longitudinally at almost 180° to the wheel 10. Driving of the wheel 10 takes place, for example, by means of a motor 13 via an endless element 14 and a drive wheel 15. The wheel 10 is fastened in conventional manner to a locationally fixed supporting construction 17. Fig. 2 shows a wheel according to the invention that has an inner layer 20, an intermediate layer 30, and an outer layer 40. 7 The inner layer 20 forms a relatively stiff or rigid base body that is formed in integral manner with a not-shown rim body of the wheel 10 or is fastened to such a rim body. The inner layer or base body 2 0 can be made, for example, of PA-GF30, PP-GF30, PA-G, or of another suitable material, for example metal, with similar material properties. The intermediate layer 3 0 borders radially onto the inner layer 20 and is so connected with the latter in suitably non-rotatable manner that rotation of the rim body with the inner layer 2 0 causes synchronous rotation of the intermediate layer 30. The intermediate layer 3 0 is formed from a body of a solid material that in itself, which means when it is not under stress, is not only stable in volume like the tire cover of a pneumatic tire, but also stable in form and is sufficiently elastically deformable. In axial direction, the intermediate layer 30 is bounded by two radial bounding surfaces 31, 32, as indicated in Fig. 2. In addition, the intermediate layer 30 has a plurality of recesses 34 that extend between the radial bounding surfaces 31, 32. In the present exemplary embodiment according to Fig. 2, in a cross section perpendicular to the axis of rotation A, the recesses 34 are slit-shaped. The recesses 34 communicate with the outside of the intermediate layer 30 and thereby form breakthroughs, or at least breakouts, and are therefore filled with ambient air. The purpose of the recesses is to increase the elastic deformability of the intermediate layer 30. 8 The recesses 34 can also have another form, for example rhomboid or rectangular, and another arrangement, e.g. single or multiple, and can be enclosed in the intermediate layer 3 0 and can be filled with air or a suitable gas. In other words, the recesses 34 can contain a compressible, preferably fluid, material. As already stated above, the solid material from which the body of the intermediate layer 3 0 is formed, is readily elastically deformable. Within the context of the present description, materials that can be considered as readily elastically deformable are such materials as have a modulus of elasticity in the range of approximately 10 to 50 MPa. Suitable materials are, for example, PUR, elastomers, NBR, SBR, and other materials with similar material properties. Especially suitable are materials that allow formation of an intermediate layer 30 that is particularly readily deformable in the radial direction, but that in the tangential direction or the direction of the circumference is stable in form and less elastic. Adjoining an outer circumferential surface 32 of the intermediate readily deformable layer 30, an outer layer 40 is provided, The outer layer 40 is joined to the intermediate layer 30 in such manner that rotation of the intermediate layer 30 causes synchronous rotation of the outer layer 40. The connection of the intermediate layer 30 to the outer layer 40 is such that the said motional coupling is attained through frictional engagement or bonding or fusion. The outer layer 40 is pretensioned outward (radially) through the intermediate layer 30, which in installed state means toward the handrail 11. This means that the outer layer 40 rests under pressure against the handrail 11. This pressure, the size of the contact surface in which the outer layer 40 and the handrail 11 touch, and the materials and structures of the outer layer 40 and of the handrail 11, determine the friction between the outer layer 40 and the handrail 11. This friction is so great that on the driven wheel 10 there is permanent frictional engagement between the outer layer 4 0 and the handrail 11 so that the rotation of the wheel 10 is constantly (i.e. without occurrence of the slip-stick effect) transformed into movement of the handrail 11. The outer layer 40 is a covering which has on an outer surface that is intended to rest against the handrail, preferably on a circumferential surface, ribs 42. In the exemplary embodiment shown, these ribs run in the direction of the circumference and are therefore referred to as longitudinal ribs. The actual contact surface with which the outer layer 40 rests against the handrail 11 is formed by the outer bounding surfaces of the ribs 42. The outer layer 40, or covering, is readily elastically deformable. Suitable materials for manufacturing the outer layer are, for example, elastomers, NBR, SBR, HNBR, and other materials with similar material properties. Shown in Fig. 3 is a wheel that differs from the wheel 10 of Fig. 2 as follows: In a cross section perpendicular to the axis of rotation A, the recesses 34 of the intermediate, readily elastically deformable, layer 30 are not slit-like but circular, i.e. the recesses are cylindrical and the axes of the cylindrical recesses run parallel to the axis of rotation of the wheel 10. 10 The wheel 10 shown in Fig. 4 differs from the wheel of Fig. 2 as follows: The outer layer 40 has a stiffening 50. In the present exemplary embodiment, this stiffening 50 is enclosed within a sub-layer 41 of the outer layer 40. Serving as the actual stiffening 50 are wires, for example metal wires, or fabrics, for example glass fiber or kevlar, that extend in the direction of the circumference. The sub-layer 41 is thus joined with the outer layer 40, and possibly also with the intermediate layer 30, in such manner that with respect to rotational movement it is also coupled with every adjacent layer 40 and possibly also 30. The stiffening 50 can also be arranged inside or on the outer layer 40 itself. The purpose of the stiffening 50 is so that the outer layer 40 rests perfectly against the handrail 11, since the outer layer 40 is readily deformable and soft but at the same time formation of bulges and the associated disadvantages must be avoided. As an alternative to the above embodiments, a wheel of several layers is also conceivable in which instead of the plurality of recesses in the material, several hard and soft layers result in the same behavior as in the wheel described above. 11 |
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| Patent Number | 265509 | |||||||||
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| Indian Patent Application Number | 985/CHE/2006 | |||||||||
| PG Journal Number | 09/2015 | |||||||||
| Publication Date | 27-Feb-2015 | |||||||||
| Grant Date | 26-Feb-2015 | |||||||||
| Date of Filing | 07-Jun-2006 | |||||||||
| Name of Patentee | INVENTIO AG | |||||||||
| Applicant Address | Seestrasse 55, CH-6052 Hergiswil, | |||||||||
Inventors:
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| PCT International Classification Number | B66B23/00,23/04 | |||||||||
| PCT International Application Number | N/A | |||||||||
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