|Title of Invention||
A WET GRINDER
|Abstract||The wet grinder of this invention consists of a drum with a stone base plate having a tubular body integrally formed at the centre. A drivable shaft is housed in the tubular body. A roller assembly held in position on the top of the shaft consists of two rollers mounted on shafts which are made to rotate against the base plate. Driving means consisting of a motor, pulley, belt and wheel assembly is electrically operable. The drum is provided with a closure means. 57) Abstracf.- The wet grinder of this invention consists of a drum with a stone base plate having a tubular body integrally formed at the centre. A drivable shaft is housed in the tubular body. A roller assembly held in position on the top of the shaft consists of two rollers mounted on shafts which are made to rotate against the base plate. Driving means consisting of a motor, pulley, belt and wheel assembly is electrically operable. The drum is provided with a closure means.|
This invention relates to a wet grinder particularly an improved table top wet grinder. Wet grinding cereals, pulses, coconut and masalas forms an essential part of every day cooking in Indian homes. Conventional methods of manual grinding using stone grinders have become more of less obsolete particularly in city homes. Modern techniques and devices have been developed to meet the demands of the consumers. Mixies and liquidisors made their appearance first. Being considerably small, mixies served only a limited purpose. Moreover, due to the high speed of rotation and because of the metallic grinding blades, the dough or batter ground in a mixie is found unsatisfactory for making every day South Indian dishes like dosas and idlis. The main reason is that the J_«^I. t^^'^^ heated during the proceso cT grinding. The texture and the taste of food items are also foumi to be substantially inferior to the food articles made from batter ground in the conventional manner. Electrically operated stone wet grinders were then developed, which avoided certain draw-backs of the mixie grinding. Larger quantities of food can be ground in such grinders and as both the surfaces in contact with the cereal and the like are made of stone, excessive heating of the batter is avoided. Low speed rotation also helps in preventing the batter from getting heated. Grinders of this type occupy large floor space, are difficult to lift and clean after operation and lack visual appeal, particularly in modern
kitchens. To overcome the problem of lifting and for effective transfer of the ground batter, wet grinders of the tilting type have been developed. Such tilting wet grinders found good markets, particularly in cities.
Table top wet grinders followed the tilting type and are developed to go with the modern decor and style of city kitchens. They are light weight as most of the components are made of moulded plastics, easily detachable and occupy very little space. A major advantage of this type is that the ground batter can be stored in the container or drum which is detachable from the unit. This avoids wastage likely to occv-r durr^^ r..«.-.^.^ej. of contents.
Table top wet grinders commercially available now have a rotatable drum or container mounted on a base frame. The base of the container is made of stone and has a centrally located shaft for transmission of rotary motion from the drive means. A roller assembly held from an arm mountable on the mouth of the drum rests on the shaft. The roller assembly has at least two stone rollers held in close contact with the stone base of the drum or container. The roller assembly is detachable from the arm, when necessary. The shaft for rotatably moving the drum is sealed in
leak-proof manner to the base stone. A similar opening for introducing the shaft has to be made on the base stone and is sealed to prevent leakage subsequent to the introduction of the shaft. Sealing may wear off and the container may leak at the joints in the course of time. Friction caused by the movement of the container around the axis of the shaft enhances the possibility of leakage.
The lid of the existing table top grinder has two parts, one on either side of the centrally located arm which holds the roller assembly, thereby making the operation of assembly and detaching cumbersome.
The improved table top wet grinders avoid the draw-backs discussed hereinabove. They are portable, light weight, leak-proof and are easily assembled. The drum or container is stationary while only the roller assembly is movable. The drum has a stone base and stainless steel side walls. The stone base has a centrally located hollow tubular body integrally formed therewith which extends almost upto the top of the drum or container, but below a predetermined level. The height of the hollow tubular body is to be kept well above the paste and the liquid level to prevent the batter from getting in. A rotatably driven shaft is housed in the centre of the hollow tubular body
and extends above it. The shaft is driven by a motor, drive belt and pulley arrangement in the conventional manner.
The roller assembly consists of at least two stone rollers held by roller shafts positioned perpendicular to the main shaft and horizontal to the stone base plate of the drum or container. The detachable roller shaft assembly is mounted over the hollow tubular body and the central main shaft. A holder consisting of two parts hold the roller assembly in position, and the shaft is coupled to the roller assembly through this holder means. The drive of the shaft is taken to the roller assembly from the top through the ho3.:Jir.to -.oo>.;„ which is spring loaded. The tup pari-of the two part holder means is preferably in the shape" of an inverted cup shaped body and houses spring means. The bottom part of the holder means is provided with seating arrangement on which the top part fits snuggly. The lower half of the bottom part of the holder means is provided with the perpendicular roller shafts either integrally or gletachably. When assembled, the top part of the holder means aligns with the bottom part and is held in position by the spring means. The spring means also provide necessary compression for the roller assembly. The roller assembly including the holding means is held in position with respect to the main shaft by a locking means such as a screw
threaded lock and nut assembly. The drive point of the main shaft is taken to the top through the hollow tubular body and is transmitted therefrom to drive the roller assembly through the holding means. This avoids rotation of the drum or container, generates less heat during grinding operation, and prevents leakage. The top arm assembly which holds the roller assembly is also eliminated and the lid or cover of the container is a single unit, detachable in the normal way. The lid may be made of transparent shock resistant material. The motor and the drum or container are mounted on a base frame which houses the drive means such as the drive belt, main wheel, pulley and the like. The drum or container is mounted with the help of mounting means having bearings and bushes. The drum may be detachably mounted and can be removed by lifting up. Means to supply power to the motor as well as 'on' and 'off switches are also provided on the housing. Optionally the roller means may be provided with a wiper and a handle for lifting the assembly easily.
A wet grinder according to this Invention comprises a container having a stone base plate, a hollow tubular body located centrally and vertically on the said stone plate, extending upto a predetermined height, a roller assembly having at least two stone rollers mounted on a shaft horizontal to the said stone base plate, and perpendicular to the said hollow tubular body, the said tubular body housing drivable shaft, the upper end thereof projecting beyond the said tubular body, holding means for holding the roller assembly on the
said drivable shaft, transmitting means to transmit the rotary motion of the said shaft to the roller assembly, locking means to lock the said shaft and the roller assembly, closure means for the said container, and means for energising and rotatably driving the said shaft.
This invention will now be described with reference to the accompanying drawings.
Reference numeral (1) stands for the lid of the drum and (1A) is the handle provided on the lid. The drum is indicated by the numeral (2). The base of the drum has a stone plate represented by numeral (13). The hollow tubular body (6) located centrally on the base plate and the vertical shaft (5), which is housed therein. The shaft (5) may be made of stainless steel. The roller shaft is referenced by numeral (11) and the roller body by (9). Reference numeral (10) stands for bushes provided between the shaft (11) and the roller (9). Numerals (4) and (8) represent the top and bottom part of the holder assembly for the roller while (7) stands for the spring _
means in the top part of the holder. Locking means for locking the roller assembly with the shaft is shown by numeral (3). The cross section of the top of the shaft and the top part of the holder means that fits thereon have identical configuration.
The motor 23 drives the belt 20, and the pulley 22, and the wheel 19 to rotate the shaft (5). The motor is housed in a body (24) preferably made of fibreglass or plastics ABS. Reference numeral (21) indicates the frame which houses the drive system. The drum and the motor are mounted on the top of the frame (21).
Numerals (14), (15), (16), (17) and (18) are couples, screws, bearing holders, top seal for bearings, and bearings which are essential for mounting the shaft and the drum on the frame member. Reference numeral (12) stands for a cone bush seal which seals the tubular body and the stone base plate as additional safety means to prevent leakage. The base of the drum is not coupled with the shaft to prevent its rotation.
Method of operating the wet grinder
Cereals to be ground are introduced into the drum after required soaking, if necessary. The roller assembly should be positioned in the vertical shaft by tightening locking means
before the material to be ground is added. Required amount of water is added and the lid is placed on the drum to cover it. The switch is activated to the 'on' position. Power supply will drive the motor and the shaft which will in turn rotate the roller assembly to grind the cereals contained in the drum. When sufficiently ground, the power supply may be switched off, and the roller assembly detached and the drum may be lifted off the base frame for storing. Alternately, the batter produced may be removed and stored in a separate container.
It is to be understood that obvious equivalents and alterations known to persons cliled in. the art are within the scope of this invention and the appended claims.
1. A wet grinder comprising a container (2) having a stone base plate (13), a hollow tubular body (6) located centraly and vertically on the said stone plate, extending upto a predetermined height, a roller assembly (9, 10, 11) having at least two stone rollers (9) mounted on a shaft (11) horizontal to the said stone base plate, and perpendicular to the said hollow tubular body, the said tubular body housing a drivable shaft (5), the upper end thereof projecting beyond the said tubular body, holding means (4 & 8) for holding the said roller assembly on the said drivable shaft, transmitting means to transmit the rotary motion of the said shaft to the roller assembly, locking means (3) to lock the said shaft and the roller assembly, closure means (1, 1A) for the container and means (19, 20, 22, 23) for energising and rotatably driving the said shaft.
2. The wet grinder, as claimed in claim 1, wherein the said holding means for holding the said roller assembly consists of an upper part and a lower part,, the upper part housing spring means, fitting snuggly on seatlngs provided on the lower part.
3. The wet grinder as claimed in claims 1 and 2, wherein the said holding means and the said roller assembly is detachable.
4. The wet grinder as claimed in claims 1 to 3, wherein the said locking means for locking the roller assembly is a screw threaded lock and nut arrangement.
5. The wet grinder as claimed in any of the above claims, wherein the said hollow tubular body is formed integrally with the base of the drum.
6. The wet grinder as claimed in any of the above claims wherein the said roller assembly is provided with a wiper and a handle.
7. The wet grinder as claimed in claim 1 wherein the said closure means is ^ single piece lid provided with a handle.
8. The wet grinder as claimed in any one of the previous claims wherein the said container is made of stainless steel.
9. The wet grinder as claimed in claims 1 and 7 wherein the said closure means of the container is a transparent plastic lid.
10. The wet grinder as claimed in claim 1, wherein the said means to energise and drive the shaft consists of an electrically dirvable motor, pulleys, belts and wheels connected to the drivable shaft or a reduction gear system between motor and drive shaft.
11. The wet grinder as claimed in claim 1, wherein the cross section of the drivable shaft at the top is identical in configuration with an opening on the upper part of the holding means.
12. The wet grinder as claimed in claims 1 and 10, wherein the said motor is provided with a housing mounted on a frame member.
13. The wet grinder as claimed in claims 1, 10 and 11, wherein the frame houses the drive system like belt, pulleys and wheels.
14. The wet grinder as claimed in claims 1, 10 and 12 wherein the drum or container is mounted detachably on the top of the said frame member.
15. The wet grinder as claimed in claims 1 and 10, wherein the drum is fixedly mounted on the said frame.
16. A wet grinder substantially as herein described, with particular reference to the single figure in the accompanying drawings.
|Indian Patent Application Number||962/MAS/1995|
|PG Journal Number||30/2009|
|Date of Filing||28-Jul-1995|
|Name of Patentee||G. RAMACHANDRAN|
|Applicant Address||PLOT NO.410/2 NEHRU NAGAR KALAPATTI PO, COIMBATORE, 641 035|
|PCT International Classification Number||B24D18/00|
|PCT International Application Number||N/A|
|PCT International Filing date|