1. Field of the Invention
The present invention relates to a clutch assembly, and more particularly to a frictional clutch assembly that can transmit power in a unidirectional manner.
2. Description of Related Art
With reference to FIG. 6, a conventional unidirectional transmitting assembly (10) in accordance with the prior art comprises a driving axle (11), a transmitting sleeve (13), multiple rollers (12) and an output axle (14). The transmitting sleeve (13) is received in the driving axle (11) and has multiple cutouts (15) defined in the outer surface of the sleeve (13). Each cutout (15) has a wide segment and a narrow segment and receives one of the rollers (12). The output axle (14) is mounted in and engages with the transmitting sleeve (13) to rotate with the transmitting sleeve (13).
When the driving axle (11) rotates along a direction corresponding to the narrow segments of the cutouts (15), clockwise as shown by the black arrow, the rollers (12) will be pushed to the narrow segments of the cutouts (15) by means of the friction between the driving axle (11) and the rollers (12). Consequently, the rollers (12) will be securely engaged between the driving axle (11) and the transmitting sleeve (13), such that the transmitting sleeve (13) will rotate with the driving axle (11) and the output axle (14) will be driven to rotate.
When the driving axle (11) rotates in an opposite direction that corresponds to the wide segments of the cutouts (15), counterclockwise as shown by the white arrow, the rollers (12) will move to the wide segments of the cutouts (15). Then, the rollers (12) will freely rotate in the cutouts (15), and the transmitting sleeve (13) and the output axle (14) will not rotate and will keep stationary. Accordingly, the input power will be transmitted in a unidirectional manner.
However, the conventional unidirectional transmitting assembly (10) does not have a function of a clutch, so it is necessary to add an additional clutch device for a machine with a conventional unidirectional transmitting assembly and this renders the machine expensive.
To overcome the shortcoming, the present invention tends to provide a frictional clutch assembly to mitigate or obviate the aforementioned problems.