|Title of Invention||
IMPROVISED WET GRINDER
|Abstract||The objective is to provide a wet grinder which distributes the force exerted by the rolling stones on the base stone, evenly, accomplished by increasing the number of rolling stones to three at the sam e tim e without increasing the total weight of the rolling stones, placed in such a manner that the surface of the base stone and the rolling stone match with each other. Rolling stones carrying grooves are rotatably mounted on the pin members of the stump assembly about its axis and kept under apre determined force on the base stone. Since the force exerted by the spring and the rolling stone 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. Further, the stump assembly is provided with a handle to arrest any rotational movements.|
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 the rolling actions created by rotating the rolling stone on the base stone, manually. Later this process was improved by the use of an electric motor to rotate the base stone.
Further improvement was the use of two rolling stones 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 roiling 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 die 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 grmamg 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 three rolling stones are placed at 120 degrees from each other on the base stone, such that the axis of the stump assembly is lying coaxially with the base stone. If the number of rolling stones are two, the concentration of Force (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 die base stone, marginally. Since the number of rolling stones is 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 is "a", then the stress induced in the base stone will be F/2a (for two rolling
stones) and F/3a (for three rolling stones). Obviously, the force (F) distribution is more for die three stones.
The three rolling stones (4) of Fig(l) are co-axially mounted on the pin members (5) of Fig(l), 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 grooves on their surfaces to enable better grinding.
The Conical Base 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 handle, arrests the rotational movem ent of the stump assembly and holds it in its place, firm ly.
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) and pulleys, which is connected by a "V" 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 tapered rolling stones are ro tat ably mounted on the equally placed pins. A suitable spring arrangement is made on the top of the stump (1) of Fig (1), to 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 the 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 die base stone.
The grinder consists of a drum (3) of Fig (1), which is having the base stone (6) of Fig(l), mounted on the driving shaft by means of an adapter. The drum is a portable one.
The 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 conical base of the stump assembly.
The stump assembly consists of a stump (2) of Fig (1) with a conical base. The three pins are rigidly inserted into the conical base at half of the angle of the 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).
The whole arrangement is supported by abase 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.
Fig (1) shows the complete assembly of the present improvement.
Figures (2) and (3) show 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 grinding efficiency increases.
2. The grinding time is drastically reduced, since the frequency of the 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 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 stone being matched with each other; the rolling stones carrying grooves being rotatably mounted on the pin members of the stump assembly about its axis and kept under 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 frequency of the food grains passing through the grinding stones, increases.
2) An Improvised Wet Grinder as claimed in Claim(1), wherein the stump assembly has a handle, whose purpose is to arrest the rotational movement of the stump assembly and hold the stump assembly in its place, firmly.
3) An Improvised Wet Grinder as claimed in Claims (1) and (2), wherein
the stump assembly is locked in place by pushing the top lid
downward and engaging it with the hinge provided for that 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 ltd.
4) An Improvised Wet Grinder as claimed in the above mentioned three
claims and as substantially described herein with reference to the
|Indian Patent Application Number||808/MAS/1999|
|PG Journal Number||26/2007|
|Date of Filing||11-Aug-1999|
|Name of Patentee||SHRI. NATESAN RANGANATHAN|
|Applicant Address||NO:672-A,BROUGH ROAD, ERODE-638 001|
|PCT International Classification Number||A47J42/10|
|PCT International Application Number||N/A|
|PCT International Filing date|