|Title of Invention||
IMPROVISED WET GRINDER
|Abstract||This invention pertains to an improvised wet grinder consisting of a rotatable base drum driven by an electric motor. Grinder has three rolling stones which may be either straight or tapered provided at an angle of 120 degrees from the axis of each other on the base stone, by means of a stump assembly, which has a locking facility. The arrangement of the rolling stones is such that the contact surface of the base stone and the rolling stones match with each other. The rolling stone carrying grooves are mounted on pin members of the stump assembly about its axis and kept under a pre-determined force on the base stone. Since the force exerted by the spring and the rolling stones is distributed evenly on the surface of the base stone, the grinding efficiency as well as the crushing area increases, with a drastic reduction in the grinding time.|
This improvement relates to a Wet Grinder:
Wet Grinders are used to grind the food grains like rice, dhal etc., In olden days it consisted of a fixed base stone and a rolling stone. Grinding takes place due to the rubbing and rolling actions created by rotating the rolling stone on the base stone manually. Later this process was improved by use of an electric motor to rotate the base stone.
Further improvement was the use of two rolling stories and a rotating base stone. The rolling stones get power from the base stone, by means of friction between the contacting surfaces. The rolling stones are kept under a predetermined pressure for effective grinding of the food grains. The grinding of food grains takes place by means of repeated rubbing and rolling actions between the contacting surfaces.
A predetermined force (F) is required to place the rolling stones on the rotating base stone. The force available by means of the weight of the rolling stones and other means like spring tension etc., is usually more than enough to grind the wet food grains in any of the methods described earlier.
The objective of the present improvement in the process of wet grinding is to distribute the force exerted by the rolling stones
on the base stone, evenly. This is accomplished by increasing the number of rolling stones to three, without increasing the total weight of the rolling stones (W), as in the earlier processes.
In order to achieve this, the number of rolling stones are placed 120 degrees from each other on the base stone, such that the axis of the stump assembly is lying co-axially with the base stone. If the numbers of rolling stones are two, the concentration offeree (F) on the base stone at the contact area (A) is more when compared with three rolling stones. (F/2 is greater than F/3). Since the available force is same, the stress F/A induced in the base stone at the contact area is less for three stones. By this, the available force is more evenly distributed along the line of contact with the rotating base stone and this also increases the area of contact between the rolling stone and the base stone, marginally. Since the numbers of stones are increased to three, the food grains are crushed in between the stones more frequently in a revolution.
If the available force is F and the area of contact with the base stone by a rolling stone is a, then the stress induced in the base stone will be F/2a (for two rolling stones) and F/3 a (for three rolling stones). Obviously the force (F) distribution is more for the three stones.
The three rolling stones (4) of Fig. (1-A) are co-
axially mounted on the pin members (5) of Fig. (1-A), such
that the contacting surfaces being matted with each other, so as to
roll freely on the base stone. The rolling stones are provided with
i grooves on their surfaces to enable better grinding.
* The stump incase of straight rollers and the conical base incase of taper rollers, of the stump assembly is having a hole on its bottom surface, which is perfectly centered with the male pin of the base stone while mounting.
* The top portion of the stump assembly having a stump head arrests the rotational movement of the stump assembly and holds it in its place firmly, while locking.
The stump assembly is locked in place by pushing the top lid downward and engaging it with the hinge provided. It exerts a compressive force by the spring holder assembly on the stump. The top lid can be released by pressing a button and then the stump assembly can be removed from the drum.
The power is obtained from an electric motor to drive the
main shaft (7) of Fig. (1-A) and pulleys, which is
connected by a CV belt. The drum is connected with the driving shaft and pulley by a suitable arrangement.
The three rolling stones, mounted on the three pins are placed at an angle of 120 degrees from each other. The three
straight or tapered rolling stones are rotatably mpunted on the
equally placed pins. A suitable spring arrangement is made on the
top of the stump (1) of Fig. (1-A), keep the rolling stones in
their position on the base stone, in order to roll on it.
The stump assembly is mounted co-axially with the rotating base drum under a predetermined force against the base stone so as to avoid the rolling stones being carried away by the base stone and permitting the rolling stones to revolve around their axes and roll over the base stone.
The grinder consists of a drum (3) of Fig. (1-A),
which is having the base stone (6) of Fig. (1-A) mounted
on the driving shaft by means of an adapter. The drum is a portable
* The straight or tapered rolling stones are rotatably mounted on the pin members at an angle of 120 degrees from each other. The pins are rigidly mounted on the roller head of the stump assembly in the case of straight rollers. In the case of taper rollers the pins are rigidly mounted on the conical base (8) of Fig. (3) of the stump assembly.
* The stump assembly consists of a stump (2) of Fig. (1-A) with a roller head for straight rollers or conical base for taper rollers. For the straight rollers the equally placed (120 degrees each other) three pins are rigidly inserted into the roller head (8) ofFig(3-A) of the stump assembly with an angle of 90 degree as shown in the Fig (1-A). For the taper rollers the three pins are rigidly inserted into the conical base at half of the angle of tapered rolling stone.
The drum can be removed from the driving arrangement by
lifting and can be placed in position by pushing it on the shaft (7)
of Fig. (1-A).
The whole arrangement is supported by a frame and is enclosed in a cover. The top lid is fixed to the cover, which can be locked or unlocked.
To perform the grinding operation, the wet food grains like rice, dhal etc., are put into the drum after the grinder is powered on. By the rolling action of the roller stones on the base stone, the grinding takes place. When the grinding is complete, the motor is switched off and the top lid can be opened. The stump assembly with the rolling stones can be removed from the drum. Then the drum can be lifted to collect the grounded material
The figure (1-A) shows the complete assembly of
the present improvement.
Figure (2-A) & (3-A) shows the stump assembly with the three rolling stones placed at 120 degrees, apart.
Advantages of the present improvement:
1. Since the force exerted by the spring and rolling stones is distributed evenly on the surface of the base stone, the efficiency of the grinding increases.
2. The grinding time is drastipally reduced, since the frequency of
food grains passing through the stones increases.
3. The area of contact is increased due to the increase of number
of rolling stones, which in turn increases the crushing area.
1. An Improvised Wet Grinder, consisting of a rotatable base drum,
driven by an electric motor with three straight or tapered rolling stones
placed at an angle of 120 degrees from the axis of each other on the
base stone, by means of a stump assembly, the arrangement being in
such a way that the contact surface of the base stone and the rolling
stones being matched with each other. The rolling stone carrying
grooves being rotatably mounted on the pin members of the stump assembly about its axis and kept under a predetermined force on the
base stone and since the force exerted by the spring and the rolling
stones is distributed evenly on the surface of the base stone, the grinding efficiency increases and the crushing area is also increased due to the increase in the number of rolling stones to three and consequently a drastic reduction in the grinding time, since the efficiency of the food grains passing through the grinding stones, increases.
2. An Improvised Wet Grinder as claimed in Claim (1), where in the
stump assembly has a stump head, whose purpose is to arrest the
rotational movement of the stump assembly and hold the stump
assembly in its place firmly, while locking.
3. An Improvised Wet Grinder as claimed in Claim (1) & (2), wherein the stump assembly is locked in place by pushing the top lid downward and engaging it with the hinge provided for the purpose, a compressive force being exerted by the spring holder assembly on the stump and stump assembly can be easily removed from the drum by pressing the button on the top lid.
|Indian Patent Application Number||641/MAS/2000|
|PG Journal Number||23/2010|
|Date of Filing||10-Aug-2000|
|Name of Patentee||NATESAN RANGANATHAN|
|Applicant Address||672-A, BROUGH ROAD, ERODE-638 001, TAMILNADU, INDIA|
|PCT International Classification Number||A47J 43/04|
|PCT International Application Number||N/A|
|PCT International Filing date|