Title of Invention

A GRINDER WITH IMPROVED LOCKING SYSTEM

Abstract

This invention relates to a grinder with improved locking system. The said locking system is provided on one end of a top arm mounted on one side of the grinder. The locking system has a spring loaded plunger, a partially rotatable knob member connected to a set of cams for compressing and decompressing the spring. A slider member is operably connected to the locking system which actuates a hook to lock the arm with the locking pin. Rotation of the knob in the other direction decompresses the spring and release the hook from the locking pin. The plunger assembly may be provided with a top nut and a bottom nut provided with the sleeve of the housing. The bottom nut is movable along with the sleeve member.

Full Text

This invention relates to a grinder with improved locking system. The grinder may particularly be a table top wet/dry grinder. Everyday Indian cooking requires dry/wet grinding of masalas, pulses and cereals. Mixies and liquidisers initially used in modem kitchens for wet and dry grinding were found inadequate mid were replaced by electrically operated stone finders. This type avoided the main drawbacks of maxi grinding and allow processing of larger quantities of food. Taste, texture and flavor of the food items cooked therewith matched the conventional food products. However, these grinders occupy large floor space, are not visually appealing, and are difficult to lift and clean. Tabletop wet grinders are developed thereafter combined utility and visual appeal. Dry and wet grinders available in the market at present have various types of locking mechanisms. One type of the popular grinders has an ann hinged at one side thereof and is locked at the other side during the process of grinding. A spring loaded locking system locks the roller shaft and exerts pressure on the grinding stones when locked. The top arm has to be pressed with considerable force to compress the spring and load. The arm gets locked in position automatically. After finding, the arm is pressed further to release the lock and is then rotated about its pivot to facilitate removal of the drum. In yet another popular model of wet/dry grinder, the base of the grinder is provided with a central rod into which the drum with its central shaft is positioned. The roller shaft is assembled and its stem is held in position with the central shaft by a lock nut. This is also considered to be a tough operation. This invention has been developed in order to overcome multiple operations of loading and locking. Compression of the spring is made easy and the pillar or support on which the top arm is pivoted in the hitherto known grinders is eliminated. This avoids a major hindrance during placing and removal of the drum on to the base of the grinder. Furthermore, the grinder assembly is made very contact. The grinder according to this invention has a rotatably drum or container positioned on a base frame. The base of this drum is made of stone and has a central shaft sealingly positioned within for transmitting rotary motion from the drive means. A roller assembly consisting of at least two rollers on a roller shaft provided for positioning latched to the central shaft. A top arm is pivotably mounted on the housing member for positioning a lid tort the container thereon. One end of the top arm is provided with a coupling means to couple the roller shaft with the top arm. This coupling means is also provided with a spring loaded plunger assembly which aligns with the roller shaft when in position and holds it in place while exerting load during grinding. A partially rotatably knob member rests on a pin centrally located on the spring loaded plunger assembly housed in a housing. A spring member of the plunger assembly is comprised and decompressed when the knob is rotated in the clock-wise or anti clockwise direction to exert spring load on the roller shaft. A slider mechanism is associated with the coupling means and is located on the top arm. A hook and lock pin arrangement locks and unlocks the top arm when the knob is rotated appropriately. Thus, the locking and unlocking which is automatic and do not require any other tedious operation as seen in the existing grinders. The spring loaded plunger assembly may have a set of cams. The top cam is rotatable with the knob and the bottom cam moves up and down guided by the housing. Downward movement of the bottom cam compresses the spring member and creates the load for grinding. Both the top and the bottom cams have a set of gradually tapered face cams matching with each other to facilitate the up and down movement of the bottom cam. In this embodiment, after the arm is placed horizontal above the drum, the knob is rotated in the anti clockwise direction to facilitate the slider mechanisms provided on the arm to rotate the hook which locks against the pin provided therefor and further rotation of the said knob compress the spring to create load on roller shaft for finding. In yet another embodiment of the locking system used in the grinder of this invention, a compression spring is sandwiched between a top nut and a sleeve fitted with a bottom nut which butts against the bottom face of the top nut. The sleeve is fitted with the bottom nut through pins in such a way that the bottom nut can slide up and down along with the top nut, spring and the sleeve. A long pitch threaded pin is provided to facilitate movement of the top and bottom nuts by taking the sleeve along with their movements. The top nut is guided by the housing and the bottom nut is guided by the sleeve which prevent the rotation of the nuts but permits only up and down movement. The rotatably knob compresses and decompresses the spring. The top dead center of the assembly is fixed and the bottom dead center is flexible. This enables to correct the variation in the height of the roller shaft assembly due to wear of the rollers. In the resting position, the spring is supported by the long pitch threaded pin which forms an integral part of the knob through the sleeve, pins and the bottom nut. After placing the arm horizontal above the drum, the knob is rotated to move the slider mechanism to rotate the hook for locking the arm against the lock pin. The locking system moves down the sleeve till the sleeve rests on the central stem of the roller shaft. A further rotation of the knob releases the sleeve by moving the bottom and the top nuts downward slightly. This frees the bottom nut from the spring and the spring load rests on the sleeve and hence on the roller shaft. In this condition, the bottom nut will be resting on the sleeve to arrest it from moving up during the grinding process. In this embodiment of the locking system, the compression of the spring and hence the grinding load is kept uniform or constant throughout the life of the grinder. This is because of the flexibility permissible in the downward movement of the sleeve. When the knob is rotated in the opposite direction the lop and the bottom nuts move up, picking up the sleeve from its seat on the roller shaft. This facilitates the release of a spring load, and the slider mechanism unlocks the hook from the locking pin. The arm is rotated and the drum is removed from is base. When the arm is placed horizontally above the drum, there is enough clearance between the roller shaft and the sleeve. Hence there is no spring load initially which reduces the fatigue of locking the arm. The arm may also be provided with a seating for placing the lid or cover member thereon. The grinder with improved locking system according to this invention comprises a rotatable stone based drum provided with a centrally located shaft, a roller shaft consisting of at least one pair of roller stones at one end thereof positioned latched to said central shaft, a fittable top arm pivoted MI one side of said grinder, the other end of said arm being provided with a locking system for locking said arm with said roller shaft, said locking system consisting of a housing containing a spring loaded plunger assemblv thereon, a partially rotatable knob member connected to a central pin of said plunger assembly wherein partial rotation of said knob member in one direction compresses said spring loaded plunger assembly, and exert load thereon while partial rotation in the opposite direction decompresses the same to release the spring load and the said locking system consists of a slide member operably connected to a hook and lock pin assembly, means for energizing the grinder and a detachable cover member for said drum. This invention will now be described with reference to the figures in the accompanying drawings. Fig. 1 shows the sectional view of the grinder with one embodiment of the locking system. Fig. 2 - A shows the sectional view ofthe locking system shown by 'A' in Fig. 1 and a bottom view of the same is shown in Fig. 2 -B. Fig. 3 shows a sectional view of the grinder showing another embodiment of the locking system. Fig. 4 - A is a sectional view of the portion marked *B' in Fig, 3 and Fig. 4 - B is a bottom view of the same. In Fig. 1 reference letter B indicates the base of the grinder assembly. Reference letters HM stand for the housing for the motor of the grinder. The drum is shown by letter D and SBP indicates the stone base plate. CS stands for the central shaft while RS indicates the roller shaft. The locking system is generally indicated by reference letter A. In Fig. 1 reference numerals 1, 2, 3 and 4 represent the lock pin, hook, the top arm and the slider mechanism respectively. Fig. 2 - A which is an exploded view of the portion marked 'A' in Fig. 1 shows one embodiment of the improved locking system. Reference numerals 5, 6, 7 and 9 indicate the partially rotatable knob, the center pin of the plunger assembly, the top cam and the bottom cam respectively. Reference numeral 8 shows the matched circular taper wedges of the face cam. Reference numeral 10 indicates the spring. The housing for the plunger is shown by numeral 11 and the sleeve member is shown by reference numeral 12. The lid or cover member is shown by reference numeral 14 in figure 1. Fig. 2 -B shows a bottom view of the portion shown in Fig. 2 - A. The second embodiment of this invention is shown in Fig. 3. The same reference numerals and letters are used to identify the components common in both the embodiments. The improved locking system is indicated by reference letter 'B' and a sectional view of which is shown in Fig. 4 - A Reference numeral 5 in Fig. 4 -A stands for the rotatable knob member. Reference numerals 15, 16, 17 and 18show the long pitch threaded pin, cam, top nut and bottom nut respectively. Reference numerals 10 and 11 show the spring member and the housing respectively. Reference numeral 19 indicates the pin. Fig. 4 -B is a bottom view of the same. The functions of the components and the operation of the grinder have been described herein before. Though the invention has been described herein above with specific embodiments, obvious alterations and equivalents known to persons skilled in the art are within the scope of the appended claims. WE CLAIM : 1. A grinder with improved locking system comprising a rotatable stone based drum provided with a centrally located shaft, a roller shaft consisting of at least one pair of roller stones at one end thereof positioned around said central shaft, a top arm pivoted on one side of said grinder, the other end of said top arm being provided with a locking system for locking said arm with said roller shaft characterized in that, said locking system consists of a housing containing a spring loaded plunger assembly, a partially rotatable knob member coimected to the central pin of said plunger assembly, partial rotation of said knob member in one direction compresses said spring loaded plunger assembly and exerts load on said roller shaft while partial rotation in the opposite direction decompresses the same to release load from said roller shaft, a slider member associated with said locking system and operably connected to a hook and lock pin assembly means for energizing the grinder and a detachable cover member for said drum. 2. The grinder as claimed in claim 1 is a wet grinder. 3. The grinder as claimed in claim 1 is a dry grinder. 4. The grinder as claimed in claim 1, wherein said spring loaded plunger assembly has a set of cams, comprising a top cam and a bottom cam, said top cam rotates along with the knob member and bottom cam moves up and down to compress the spring. 5. The grinder as claimed in claims 1 to 4 wherein said set of cams has a top cam and a bottom cam interfaced with tapered face cams. 6. The grinder as claimed in any one of the preceding claims wherein said housing has a sleeve member operably connected to said set of cams, the spring and the knob member. 7. The grinder as claimed in claim 1 wherein said locking system has a compression spring sandwiched between a top nut and a sleeve member provided with a slidable bottom nut such that said bottom nut is movable up and down within said sleeve member. 8. The grinder as claimed in claim 7 wherein said bottom nut is provided within said sleeve member through pins. 9. The grinder as claimed in claim 7 wherein a long pitch threaded pin is operably associated with said knob member to facilitate up and down movements of said top and bottom nuts. 10. The grinder as claimed in claims 1 to 8 wherein said top arm is provided with a provision or seating for the lid or cover member.

Documents:

814-mas-2002 abstract.jpg

814-mas-2002 abstract.pdf

814-mas-2002 claims.pdf

814-mas-2002 correspondence others.pdf

814-mas-2002 correspondence po.pdf

814-mas-2002 description (complete).pdf

814-mas-2002 drawings.pdf

814-mas-2002 form-1.pdf

814-mas-2002 form-18.pdf

814-mas-2002 form-26.pdf

814-mas-2002 form-3.pdf