|Title of Invention||
"DEVICE FOR TRANSLATING ROTARY INTO RECIPROCATING MOTION USING FIXED --UP CHAIN"
|Abstract||A device for translating rotary into reciprocal motion, of particular valve for pumps, that comprises a linked-up chain 14 that is held by plates 15 & 16 so that it can only move as part of an assembly 2 in a reciprocating fashion and in which a sprocket 9, mounted on the shaft 10 of a gearbox, is held in engagement with the inside of the chain by having the gearbox mounted on a bracket 8 which can oscillate about a fixed axis of bearing 13 and by a cam follower 11 riding on a cam 12 that is mounted on the same assembly as the chain.|
|Full Text||DEVICE FOR TRANSLATING ROTARY INTO RECIPROCATING MOTION USING A FIXED. LINKED UP CHAIN
The invention relates to a device for translating rotary into reciprocal motion of particular value for mechanizing a reciprocating hand-pump.
The common method of obtaining reciprocal motion from a rotating motor is to attach a crank to an eccentric mounted bearing. The method is not efficient for cycle times over one second duration and long strokes because the out-of-balance loading on the motor necessitates the use of a heavy flywheel. Other methods have been proposed using twin racks with one or more pinion gears but none are as simple and low in cost as the method here proposed.
According to the present invention there is provided a linked-up chain that is held in a fixed shape, normally an oval, and moves only as part of an assembly. This assembly is caused to move by a sprocket located so that it engages the inside of the chain. The movement is constrained to reciprocate by guide wheels running on a track. The sprocket is fixed to the shaft of an electric motor, or gearbox driven by a motor, and rotated in one direction only. The teeth of the sprocket are maintained in engagement with the links of the chain by a cam follower consisting of a ball or needle bearing in contact with a cam that forms part of the same assembly as the chain. The cam follower normally rotates about the same axis as the sprocket and may be mounted on the motor or gearbox shaft. The gearbox or motor/gearbox unit
itself oscillates through a small angle so that the sprocket can maintain contact with the chain.
A specific embodiment will now be described by way of example with reference to the accompanying drawings in which :
Figure 1 shows an installation comprising a hand-pump 1 operated by the device of which the moving assembly 2 is linked to the pump connecting rod 3 and, via a pulley wheel 4, to the pump handle 5 which acts as a counterbalance weight that not only balances the weight of the device plus that of the pump connecting rods but also balances half the weight of the water column so that the load on the motor remains approximately the same for both upstroke and down stroke. The device is powered by a motor 6 which receives DC current directly from a photo-voltaic solar array 7. The gearbox linked to the motor is clamped in a support bracket 8 which is free to rotate about axis AA.
Figures 2 and 3 show a device of the invention. Figure 3 is a section through BB. In Figure 2, the moving assembly 2 is shown near the bottom of its traverse after the sprocket 9, mounted on gearbox shaft 10, has just passed across top dead centre rotating in a clockwise direction. The cam follower 11, which is in contact with cam 12, is rotating in an anticlockwise direction. The motor support bracket 8 is attached to bearing 13, so that the sprocket is kept in close engagement with the inside of the endless chain 14 as shown in Figure 3. The chain is held between plates 15 and 16. The moving assembly
is constrainted to traverse in a reciprocating fashion by guide wheels 17 running on track 18.
With the sprocket mounted on a conventional free - wheel device the pump can be operated manually without removing the motor / gearbox or the cam provided means are included for assisting movement of the sprocket across top and bottom dead centre. This can be done by flat springs that are forced against the motor casting as the moving assembly nears the end of both the top and bottom of the its traverse.
1. A device for translating a rotary motion into a
reciprocating motion in which a linked-up chain is held fixed so that it can only move as part of a whole assembly in a reciprocating fashion along a track when engaged by a sprocket mounted on a motor or gearbox driven by a motor rotating in one direction only and in which the sprocket is maintained in engagement with the inside of the linked-up chain by means of a cam follower, mounted on the same axis as the sprocket, riding against a cam which forms part of the assembly incorporating the chain and in which the motor or gearbox driven by a motor oscillates about a fixed axis so as to maintain the sprocket in engagement with the chain.
2. A device as claimed in claim 1 used to drive a water pump having a counterbalance weight of a magnitude such that the load applied to the motor of the device is approximately the same on the downstroke as on the upstroke.
3. A device as claimed in claims 1 or 2 used to drive a water pump and in which the sprocket is mounted on a free-wheel such as that normally fitted to a bicycle so that the pump can be operated solely by hand if means are provided to assist the movement of the sprocket across top and bottom dead centre.
4. A device as claimed in claims 1, 2 or 3 in which the cam
can easily be moved out of contact with the cam follower
and the sprocket located so that it does not come into
contact with the chain so that the pump can be operated
entirely by hand instead of the motor.
5. A device as claimed in claims 1, 2, 3 or 4 which is
powered by a motor supplied with electricity from
|Indian Patent Application Number||36/DEL/2002|
|PG Journal Number||34/2008|
|Date of Filing||18-Jan-2002|
|Name of Patentee||TRANSRURAL TRUST|
|Applicant Address||17, NARROW HILL, WITNEY, OXON OX8 6DF|
|PCT International Classification Number||F16H 19/02|
|PCT International Application Number||N/A|
|PCT International Filing date|