FIELD OF THE INVENTION

The present invention, in general, relates to wet grinders. Particularly, the present invention relates to a pedal operated wet grinder devoid of chains or belt transmission. More particularly, the present invention relates to a pedal operated wet grinder, wherein the rotational kinetic energy from pedaling is transferred to the grinder drum through suitable bevel gear-connecting shaft assembly means.

DESCRIPTION OF PRIOR ART

The commonly used mechanism in wet grinders is:

1. Bicycle chain transmission for pedalling, and scooter wheel for changing 90 degree transmission to the grinder drum.

2. Bicycle chain transmission for pedalling, and bevel gears for 90 degree transmission to the grinder drum

However, the first type of pedal powered grinder mentioned above is not commercially viable because it needs lot of maintenance and production cost is high. The second type of grinder offers better performance, but it comes with the following disadvantages.

• Bicycle chain mechanism need chain tension adjustment. So it has to be maintained once in a while.

• Inherent accident risk if the chain and sprocket are left uncovered.
• Size of the frame is large as it has to support chain transmission and bevel gear. No aesthetic look as it resembles a bicycle.

In the state of the art literature, US Pat No. 5872413 teaches a pedal activated motor attachment for a hand operated food grinder for allowing a user to convert a hand operated machine into a pedal driven machine; US Pat No. 7253534 discloses a method and apparatus for converting human power into electricity, wherein the force exerted on the pedals is transferred to a generator via a gear-to-gear transmission assembly; US Pat No. 7504737 is continuation-in-part of the prior art identified by US Pat No. 7253534;

CCAT's Pedal Power Grinder, a published project by Bart Orlando, teaches a grinder driven by pedalling means. Similarly, pedal-powered grain grinders are known to be made by Maya Pedal (http://mavapedal.org/). a Guatemalan NGO based in San Andres Itzapa. However, the said inventions use fan belt and chain to transfer the rotational kinetic energy from the pedals to the grinder shaft.

My invention proposes a pedal operated wet grinder, devoid of any belt or chain transmission. The number of movable parts in the said design is minimal, and since chain transmission is not used in this design and this reduces overall size of the machine.

SUMMARY OF THE INVENTION

It is therefore the primary objective of the present invention to propose a compact, pedal operated wet grinder devoid of any chain or belt transmission.

It is another object of the invention to propose a wet grinder that is user friendly.

It is yet another object of the invention to propose a wet grinder that is safe and easy to maintain.

Accordingly, the present invention proposes a pedal operated wet grinder, having a frame (9) with a flattened base (8) to support the grinder on any flat surface, the said wet grinder comprising of:

• Main shaft (21) with axle bearing (19), disposed through suitable openings provided on a transmission box (10), wherein the opposing ends of the said main shaft are fixed to first and second pedal arms, bearing pedals on its free ends, respectively;

• Said transmission box (10), encompassing a driving bevel gear mounted on the main shaft (21), and a driven bevel gear (17) meshed with the said driving bevel gear, wherein suitable further openings is provided on the transmission box to receive a vertical drive shaft (12); and

• A height adjustable seat (2) with backrest, mounted on a vertical tube fixed at desired distance from the frame (9), on the flattened base (8), and a handle bar fixed below the grinder drum, on the frame, in front of the said seat.

Other objects, features, and advantages of the present invention will become more apparent from the ensuing detailed description of the invention, taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF ACCOMPANYING FIGURES

Figure 1 shows the pedal operated wet grinder.

Figure 2 depicts the gear box and associated components.

DETAILED DESCRIPTION OF INVENTION

The preferred embodiments of the present invention will now be explained with reference to the accompanying drawings. It should be understood however that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. The following description and drawings are not to be construed as limiting the invention and numerous specific details are described to provide a thorough understanding of the present invention, as the basis for the claims and as a basis for teaching one skilled in the art how to make and/or use the invention. However in certain instances, well-known or conventional details are not described in order not to unnecessarily obscure the present invention in detail.

The present invention, as per the preferred embodiments, proposes a wet grinder driven by pedal means. As illustrated in Figure 1, the said wet grinder comprises of a pedalling means consisting of two pedals (6), connected to a driving bevel gear (18) in a gear box (10) through a main shaft (21) with axle bearing (19). The said axle bearing is a sealed needle type. The gear box further encompasses a driven bevel gear (17) that is connected to a driving bevel gear (18) at 90 degrees as shown in Figure 2. The driven bevel gear is further connected to the grinder drum through a vertical drive shaft (12) as depicted in Figures 1 & 2. The said drive shaft is coupled to the grinder drum (15) through a T-slot pin in the grinder drum, as illustrated in Figure 2. Drive shaft bearings (3 & 11) support the drive shaft, meanwhile permitting it to rotate freely as the driven bevel gear drives it. The grinding drum further encompasses two grinder wheels (14), freely supported inside the casing of the said drum as shown in the figure.

A grinder central lock (4) is provided to secure the grinding wheels (14) aligned to the centre of the shaft. Two or three nos. of grinding wheels is usually provided in the grinder drum.

As per the preferred embodiment of the present invention, a frame (9) made of angle iron and mild steel tubes, supports the wet grinder assembly as shown in Figure 1. The bottom end of the said frame is a flattened base (8) that acts as the base on which the entire wet grinder assembly rests against the floor. Ninety centimetres from the transmission box, perpendicular to the base is a vertical tube, on which a height adjustable seat (2) is positioned. Fixed below the grinder drum, and on the frame, in front of the seat, is the handle bar. An adjustable backrest (16) is provided. The grinder drum and accessories are enclosed in the plastic body (13).

In order to have the grinder perform optimally, the gear ratio of the two bevel gears is suitably set to generate the desired RPM at the grinder drum. The positioning of the bevel gears also ensures a transfer of the power, at 90 degrees, from the main shaft to the drive shaft. The constituent parts of the wet grinder are housed in a circular frame of 60 cm diameter.

In another embodiment, worm and pinion gears are employed to transfer the rotational kinetic energy from the pedals to the grinder drum

As per one embodiment of the present invention, the bevel gears have a gear ratio of 3.08333. That is, if the pedals are operated at 60 RPM, it is converted to 259 RPM in the grinder drum. Here it is assumed that an average healthy human being can pedal at an RPM of 40-90. The said specification is detailed herein.

Specification

Power source Pedal operated
Transmission type Bevel geared gear box
Grinder drum 2 litres
Grinder wheels 2 numbers
Pedalling RPM 40-90
Drum RPM 123-277
Transmission ratio-pedal grinder 1:3.0833 (gear drive)
Position of seat Adjustable

Although the present invention has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications are possible and are apparent to those skilled in the art. Such changes and modifications are to be understood as included within the scope of the present invention as defined by the appended claims unless they depart there from.

I Claim:

1. A pedal operated wet grinder, having a frame (9) with a flattened base (8)
to support the grinder on any flat surface, the said wet grinder comprising of:

• Main shaft (21) with axle bearing (19), disposed through suitable openings provided on a transmission box (10), wherein the opposing ends of the said main shaft are fixed to first and second pedal arms, bearing pedals on its free ends, respectively;

• Said transmission box (10), encompassing a driving bevel gear mounted on the main shaft (21), and a driven bevel gear (17) meshed with the said driving bevel gear, wherein suitable further openings is provided on the transmission box to receive a vertical drive shaft (12); and

• A height adjustable seat (2) with backrest, mounted on a vertical tube fixed at desired distance from the frame (9), on the flattened base (8), and a handle bar fixed below the grinder drum, on the frame, in front of the said seat.

2. The pedal operated wet grinder as claimed in claim 1, wherein the axle bearing is of sealed needle type.

3. The pedal operated wet grinder as claimed in claim 1, wherein the drive shaft bearings (3 & 11) provide support to the drive shaft.

4. The pedal operated wet grinder as claimed in claim 1, wherein the vertical drive shaft (12) mechanically connects the grinder drum with the driven bevel gear.

5. The pedal operated wet grinder as claimed in claim 1, wherein the driven bevel gear (17) is meshed with driving bevel gear (18) at ninety degrees.