Centrifugal Clutch and Drive Mechanism for Remote Control Apparatus

This invention relates to a centrifugal clutch and drive mechanism for the remote control of a movable device, such as a vehicle door opener, trunk lid opener, etc.

Known remote control apparatusses include both solenoid means and a large, high torque motor coupled to a low ratio reduction gear mechanism, with both of which the remotely controlled mechanism may be operated either electrically or manually. Both the solenoid means and the motor and gear mechanism are unduly large and costly, however, consume an inordinate amount of electric current, and are difficult to install in a limited space.

To meet such limited space requirements it is logical to resort to a compact, high speed motor coupled to a high ratio reduction gear mechanism.

Such a combination creates problems, however, when there is a limiting restriction to the movement of the remote controlled mechanism and the motor remains energized. In such situations overloading may occur, and cause electrical and/or mechanical failure or damage to the system components. Furthermore, if alternate manual operation of the remote controlled mechanism must be provided for, as for safety considerations with vehicle door locks, the operator must exert considerable effort since he must "spin up" both the reduction gears and the high speed motor.

The above drawbacks and disadvantages of the prior art systems are effectively overcome by the present invention, according to which the power generated by a drive motor is transmitted through a centrifugal clutch and reduction gear mechanism to a remote controlled mechanism when the motor is energized. The centrifugal clutch is automatically disengaged and the drive train is thereby interrupted when the motor is deenergized whereby an operator may easily manually operate the remote controlled mechanism with little effort.

The centrifugal clutch is disposed between the motor and the remote controlled mechanism, and a sector gear is disposed between the centrifugal clutch and the remote controlled mechanism, the sector gear swinging over a predetermined angular range to operate the remote controlled mechanism.

In the drawings:

FIG. 1 shows a bottom view of a first embodiment of the invention,

FIG. 2 shows a partially sectional elevation view of FIG. 1, and

FIG. 3 shows an exploded view of an alternate centrifugal clutch mechanism according to the invention.

Referring now to the drawings, FIGS. 1 and 2 show an embodiment of the invention used for the remote control of an automobile door lock. A centrifugal clutch 3 is mounted on the output or drive shaft 2 of a reversible electric motor 1. The clutch comprises a disk 4 secured to the motor shaft and a pair of pins 5, 6 upstanding from the disk. The pins are positioned on diametrically opposite sides of the shaft 2, and are slidably engaged or inserted in slots 9, 10 formed in centrifugal weight members 7, 8, respectively. As a result, the weight members are constrained to rotate with the disk 4, but are able to move freely in a radial direction. A cylindrical cup 11 has an inner wall 11a loosely surrounding the weight members such that they are thrown radially outwardly into contact with the inner wall by centrifugal force when the motor 1 is energized. A gear 14 of a reduction gear mechanism 12 engages a pinion 13 axially secured to the cylindrical cup 11, and a smaller gear 15 coaxially mounted on the gear 14 engages a sector gear 16 mounted on a pivot shaft 18. An actuating rod 17 coupled to a manual control lever (not shown) for the door lock is pivotally connected to the sector gear 16. Thus, the high speed rotational movement of the motor 1 is translated into a centrifugally coupled, relatively slow speed linear movement of the actuating rod 17. The connection between the actuating rod and the sector gear is not limited to a pivotal connection, and a swingable connection may also be employed. Pivotal and swingable connections are preferable for most applications, but a rigid connection may also be used to obtain the desired linear movement. The actuating rod 17 is also coupled to the remote controlled mechanism 19, such as a vehicle door lock.

When the motor 1 is energized by a switch (not shown) near the driver's seat, for example, the disk 4 together with the pins 5, 6 begins to rotate. The weight members 7, 8 also rotate, and move radially outwardly to press against the inner wall 11a of the cup 11 by centrifugal action. As a result, the rotation of the motor 1 is transmitted to the sector gear 16 through the cup 11, the pinion 13, the gear 14 and the gear 15, whereby the sector gear 16 is driven in its range of angular movement. This in turn drives the actuating rod 17 in a substantially linear or straight manner, thereby locking or unlocking the door mechanism 19.

Even if the motor remains energized after the sector gear 16 and the actuating rod 17 have reached the limit of their movement, no damage occurs since the centrifugal clutch simply slips when an excess load is applied. The slippage threshold can be easily set by appropriately selecting the weights of the members 7, 8 and the frictional characteristics thereof.

Conversely, when the motor 1 is deenergized the weight members 7, 8 are not subjected to centrifugal action and easily separate from the inner wall 11a of the cup 11. Thus, when the door lock lever is manually operated the movement of the actuating rod 17 is not transmitted to the motor 1 since the cylindrical cup 11 simply spins in an idling or no-load manner on the shaft 2, whereby manual locking or unlocking is easily accomplished.

FIG. 3 shows an alternate centrifugal clutch mechanism 23 including a rotatable disk having an upper plate 24a and a lower plate 24b, and radial partition plates 25 fixedly inserted therebetween. Each sector-shaped weight member 27 is accomodated in a space defined by the upper plate 24a, the lower plate 24b and the partition plates 25. The functioning of the centrifugal clutch mechanism 23 is identical to that of the mechanism 3 in FIG. 1.