192 clutches and power-stop control – Transmission and brake – Torque-responsive brake
Reexamination Certificate
1999-11-05
2001-07-17
Browne, Lynne H. (Department: 3629)
192 clutches and power-stop control
Transmission and brake
Torque-responsive brake
C192S0120BA
Reexamination Certificate
active
06260685
ABSTRACT:
INTRODUCTION
This invention relates to rotary couplings, for transmitting rotary motion from a driving part to a driven part, i.e. for transmitting a driving torque.
The purpose of the invention is to provide a simple rotary coupling for use in applications where a reverse torque must not be transmitted to the driving side. By a reverse torque we mean a torque applied externally to the driven part of the coupling. In this connection the actual direction of rotation, clockwise or anti-clockwise, is immaterial; the invention is concerned with rotary couplings which are not restricted as to the direction of rotation; rather, it provides a coupling in which torque is freely transmitted from the driving side to the driven side but not vice versa.
SUMMARY OF THE INVENTION
According to the invention, there is provided a rotary coupling comprising:
a driving part and a driven part, for transmission of driving torque between them;
a fixed part in which the driving and driven parts are each rotatable coaxially;
and a set of planetary coupling members carried by one of the driving and driven parts and in torque-transmitting engagement with the other,
the coupling members being juxtaposed to an annular braking surface of the fixed part, each coupling member being free to tilt with respect to the driving and driven parts, into and out of engagement with the braking surface,
and the arrangement being such that a driving torque, applied by the driving part to the coupling members, is transmitted by the latter to the driven part without engagement of the coupling members with the braking surface; but a reverse torque, applied by the driven part to the coupling members, tends to tilt the latter into wedging engagement with the braking surface so as to lock up the coupling.
The coupling of the invention is simple and robust, and can be used in a very wide variety of applications, for example powered wheelchairs, winches, roller blinds, wheel-actuated rudders for boats and ships, and any land vehicle having a rotary transmission for driving torque between an input side and an output side, in which the coupling can for example conveniently be incorporated in the propeller shaft.
It is to be understood that the driving part could be rotated by a power drive or it could be rotated manually.
Most conveniently the coupling members are carried by the driving part.
According to a feature of the invention, with each coupling member defining a tilt axis parallel to the axis of the coupling, each coupling member is engaged by the driving part for transmission of the driving torque by a generally tangential thrust applied in a radial zone substantially closer to the tilt axis than the radial zone in which the coupling member engages the driven part.
Preferably with this arrangement, the driving part includes a planet carrier comprising a ring coaxial with the driven part, the ring having seats in which the coupling members are free to tilt in a radial plane, and which apply the driving torque. The coupling members project radially inward into the zone of their engagement with the driven part.
According to another feature of the invention, each coupling member is a roller, the major part of which is cylindrical with a cylinder axis parallel to the axis of the coupling, the cylinder being truncated parallel to its axis to define a wedging surface of the roller facing the adjacent braking surface of the fixed coupling part. Preferably then, each said wedging surface is arcuate in cross section and of slightly smaller radius than the braking surface.
In preferred embodiments, the driven member has a radial flange interrupted by seating for engagement by the coupling members.
A rotary coupling in one preferred form according to the invention will now be described, by way of non-limiting example only and with reference to the accompanying drawings.
REFERENCES:
patent: 1883087 (1932-10-01), Swartz
patent: 2052094 (1936-08-01), Huff
patent: 3022680 (1962-02-01), Van Roojen
patent: 4706791 (1987-11-01), Magliano
patent: 6068097 (2000-05-01), Kurita
patent: 0 751 032 (1997-01-01), None
patent: 839 049 (1939-03-01), None
patent: 936 954 (1963-09-01), None
patent: 984 225 (1965-02-01), None
patent: 1 042 013 (1965-09-01), None
patent: 1 571 396 (1980-07-01), None
Binda Greg
Browne Lynne H.
Samar Systems Limited
Young & Thompson
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