This invention relates to a wave spring clutch transmission system. One of the method of transmitting torque or power from one rotating member to another is a spring clutch.

The basic wrap spring clutch consists of three parts: an input hub, an output hub, and a spring. The inside diameter of the spring is slightly smaller than the outside diameter of the two hubs. When the parts are assembled and one hub is rotated in the direction that the spring is wound, the spring wraps down tightly on both hubs causing the clutch to drive under the influence of friction between the spring and the surface of the hubs. The greater the force the tighter the spring grips the hubs. When the rotation is reversed, the spring loosens its grip and slips. In the free direction the output hub, there is a slight drag caused by the spring being slightly smaller than the hubs. A tang on one end of the spring engages with a slot on the input hub, to enable the spring to be wound on the output hub when the input hub is turned.

In its simplest form the spring clutch functions as an overrunning clutch. It drives one way and slips upon reversal of rotation of the input shaft or over speeding of the output shaft beyond the speed of the input shaft; the output is free to overrun the input. It can also be used as a one-way indexing clutch or a backstopping clutch.

In the invention proposed herein, unlike the known spring clutch, a wave spring is made to provide the necessary grip on the output hub for enabling transmission of power or torque to take place by axially compressing the wave spring, as will hereinafter be clear. Consequently this invention is technologically superior to the known spring clutch transmission system resulting in the following benefits and advantages:

(i) The invention is constructionally simpler and easier to manufacture

(ii) The invention converts a circumferential turning movement of the spring into a an axial compressive movement, whereby the application of the input force on the spring is rendered more positive. The compressive movement of the wave spring can also be provided by many forms of linear actuators.

(iii) The wave spring playing a significant part in the invention is versatile, having two options: one being in multi-turn form and the other being in single turn form, either of which forms may be used depending upon the specific requirements of a particular application. The clutch will be assembled from multiple springs or single unit depending on the torque to be transmitted.

(iv) Overall, the invention is more efficient than the conventional spring clutch transmission system

Other advantages and benefits of this invention will be readily discernible from the following further description to follow:

The wave spring clutch transmission system, according to this invention, comprises an input transmission member and an output transmission member, a wave spring encircling the input transmission member and snugly receivable in a bore of the output transmission member; an actuator disposed over, and linearly movable along, the input transmission member, the actuator being thus enabled to axially compress, the said spring, to expand radially and grip the inner periphery of the said bore, thus causing a frictional torque to be applied to the output transmission member, through the said spring, the actuator, however, being linearly movable along the input transmission member, in the reverse direction, to decompress the said spring and release the said grip on the inner periphery of the said bore.

In one embodiment of this invention, the wave spring will be of a continuous multi-turn form while in another embodiment, the wave spring will be of a single turn form. In the latter form, one single turn wave spring will be used to occupy the bore of the output transmission member alternatively, a plurality of such separate single turn wave springs will be individually stacked, one against another, to form an array.

Reference will now be made to the accompanying drawings which illustrate in

Fig. 1 a clutch spring transmission system known to the art

Fig. 2 two different wave springs known to the art

Fig. 3 a profile with fins of a wave spring constituting a component of an embodiment
of this invention

Fig. 4 an input shaft (input transmission member) with splines, according to an embodiment of this invention, for engaging with a wave spring profile with fins illustrated in 3

Fig.5 an input shaft accommodated inside the bore of the output shaft with the wave spring in uncompressed state, according to an embodiment of this invention

Fig. 6 the input shaft shown in Fig.5 accommodated inside the bore of the output shaft with the wave spring in compressed state

Figs. 3 to 6 illustrate an input transmission shaft S1 and an output transmission shaft S2. A wave spring W closely encircles the input transmission shaft and is snugly receivable in a bore B of the output transmission shaft.

A hub A (actuator) is disposed over, and linearly movable along, the input transmission shaft, in the direction of the output transmission shaft, so as to butt against, and axially compress, the wave spring W. The compression of the spring causes it to expand radially and grip the inner periphery of the said bore, enabling a torque applied to the input transmission shaft to be transmitted to the output transmission shaft through the said spring. The actuator A, when moved in the reverse direction, along the input transmission shaft, de-compresses the said wave spring W to release the said grip and thus de-couple the input transmission shaft from the output transmission shaft.
In another form of the above embodiment the input transmission shaft will have splines T on its outer periphery mating with fins F on the inner periphery of the wave spring W enabling the input transmission shaft when rotated (after compression of the spring) to transmit the torque to the output transmission shaft by means of the friction grip between the outer periphery of the spring and the inner periphery of the bore of the output transmission shaft.

In the embodiment just described, the wave spring is of the multi-turn kind. It is possible in other forms of the said embodiment to use a single turn spring or a plurality of single turn springs stacked against each other in an array. In either case it is optional to have a wave spring provided with fins and the outer periphery of the input shaft with mating splines.

It will be appreciated that various other embodiments of this invention are possible without departing from the scope and ambit of this invention.

We Claim:

1. A wave spring clutch transmission system comprising an input transmission member and an output transmission member, a wave spring encircling the input transmission member and snugly receivable in a bore of the output transmission member; an actuator disposed over, and linearly movable along, the input transmission member, the actuator being thus enabled to axially compress the said spring, to expand radially and grip the inner periphery of the said bore, thus causing a frictional torque to be applied to the output transmission member, through the said spring, when the input transmission member is rotated, the actuator, however, being linearly movable along the input transmission member, in the reverse direction, to decompress the said spring.

2. A transmission system as claimed in Claim 1 wherein the wave spring is of the multi-turn kind.

3. A transmission system as claimed in Claim 1 wherein the wave spring is of the single turn kind, at least one such single turn spring encircling the input transmission member.

4. A transmission system as claimed in Claim 1 wherein the wave spring is of the multi-turn kind encircling the input transmission member.

5. A transmission system as claimed in any one of the preceding Claims wherein the input transmission member has splines on its outer periphery and the wave spring has mating fins on its inner periphery.

6. A wave spring clutch transmission system substantially as herein described with reference to and as illustrated in Figs. 3 to 6 of the accompanying; drawings.