1. Field of the Invention
This invention relates to a coupling device, and more particularly to a coupling device used in one-way rotating drive for transmitting the rotation (revolution) of a drive shaft to a driven shaft.
2. Description of the Prior Art
Rotational coupling devices are usually designed to permit transmission of clockwise and counter-clockwise torque between a drive member and a driven member. As a result the design features must be balanced for both directions of rotation. Some devices, e.g, sport equipment such as jet skiis, do not require two-direction rotational coupling devices. Consequently when one examines conventional rotational couplers from the viewpoint of only a single required rotating direction, there are several features which appear undesireable.
A conventional two-direction rotational coupler is shown in vertical cross section in FIG. 3. The coupler comprises a first flange (not shown) attached to the drive member and having claws 3 extending therefrom in an axial direction to a second flange (not shown). The second flange is connected to the driven member and has claws 4 extending therefrom toward the first flange. In between the flange faces there is an elastic circular member 8 having a thickness slightly greater than the projecting lengths of the claws from the respective flange faces. Thus, when the coupling member is assembled the claws from the flanges will almost, but not quite reach the opposite flange face.
The elastic circular member 8 has projections 5, 5' around the periphery thereof.
When the drive member rotates in the clockwise direction, as seen in FIG. 3, the clockwise torque is transmitted from claws 3 to the claws 4 via the projections 5. The projections 5 will thus be compressed by torque variation and the projections 5' will be essentially free. For counter clockwise rotation the torque will be transmitted via projections 5', which will be compressed between claws 3 and 4.
Because of the requirement for two-directional coupling, half the volume and weight of the elastic projections are free during torque transmission. Also the claws are concave on both sides thereof to permit compression in both directions and the projections are shaped to have a large heavy head and a narrow neck.