Electric/manual door lock operating mechanism
BACKGROUND OF THE INVENTION 
     This invention relates to an electric, remotely controlled, lock operating mechanism for a vehicle door, including alternate manual operating means. 
     There are two basic types of door lock operating mechanisms, one of which includes a solenoid drive and the other of which includes an electric motor drive. The former is unduly large, costly and noisy, whereby the latter has been more widely adopted in recent years. 
     In the latter type of mechanism, installation in a limited space (within a door frame) is enabled by using a small, compact motor coupled to a high ratio reduction gear mechanism. However, if alternate manual operation must be provided, as for safety consideration with vechile door locks, the operator must exert considerable effort since he must &#34;spin up&#34; both the reduction gears and the motor. To avoid this drawback a large motor and low ratio reduction gear mechanism can be used, but then the limited installation space presents a problem. 
     To obviate these drawbacks, according to Japanese patent publication No. 50-16048 a centrifugal clutch is employed which automatically disengages the drive train when the motor is deenergized, whereby manual operation may be achieved with reduced effort. The force required is still relatively large, however, since the manual control lever is connected to and must drive the high ratio reduction gear mechanism. Further, if the door is mistakenly locked by the manual control lever when the door is open, the lock is automatically released when the door is closed. During such release, however, the reduction gear mechanism is rotated at a relatively high speed, which often causes damage to or failure of the gear mechanism. 
     To obviate these drawbacks, according to Japanese patent publication No. 48-40275 as shown in FIG. 11, a manual door lock knob 100 is provided with a pawl 101 movable between an upper stop 102a and a lower stop 102b of a slide member 102. The distance between the stops is substantially equal to the stroke of the knob 100. The slide member 102 is guided in a groove 103 and is connected to the output shaft 104 of a reduction geared motor, whereby the member 102 slides on the groove 103 in response to the rotation of the motor to automatically lock or unlock the door. With this structure, the movement of the knob during manual operation is not transmitted to the reduction gear or motor as long as the slide member 102 is maintained at a neutral position between its door lock and door unlock positions. However, it is necessary to provide a mechanism for stopping the rotation of the motor when the slide member 102 is at its neutral position, and such mechanism is mechanically complicated and costly. 
     SUMMARY OF THE INVENTION 
     The above-mentioned drawbacks and disadvantages of the prior art systems are effectively overcome by the present invention, according to which the connecting linkage between the reduction gear mechanism and the manual control lever incorporates a certain degree of play or lost motion whose length is equal to the stroke of the manual control lever, whereby the movement of the latter is not transmitted to the reduction gear mechanism and a motor. Thus, manual operation is greatly facilitated and damage to the reduction gear mechanism is prevented. Further, according to the present invention a simple spring is employed to restore the neutral position of the reduction gear mechanism, whereby no complicated drive motor control is necessary and a structurally simple device is achieved. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings: 
     FIG. 1 shows a perspective view, partly cutaway, of one embodiment according to the present invention, 
     FIGS. 2 and 3 show exploded views of alternate centrifugal clutch mechanisms according to the invention, 
     FIG. 4 shows a partial front view of the connecting linkage of FIG. 1, 
     FIG. 5 shows a front view of another embodiment according to the present invention, 
     FIG. 6 shows a perspective view of still another embodiment according to the present invention, 
     FIGS. 7 and 8 show perspective views of other spring arrangements according to the present invention, 
     FIG. 9 shows a front view of still another embodiment according to the present invention, 
     FIG. 10 shows an explanatory view of a spring action according to the present invention, and 
     FIG. 11 shows a conventional door lock mechanism according to Japanese patent publication No. 48-40275. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In FIG. 1, door locking and unlocking is implemented by a lock mechanism 1 in response to the pivotal movement of a lever 2 mounted on the mechanism. A knob 3 is pivotally mounted to the lever 2 to manually operate it up and down. Reference numeral 4 designates an electrical door lock operating mechanism. For simplicity of explanation the mechanism cover has been removed in FIG. 1. A motor 6 is disposed below a casing 5, and an output shaft of the motor extends into the casing. A centrifugal clutch 7 is mounted on the output shaft. 
     As seen in FIG. 2, the centrifugal clutch mechanism 7 includes a rotatable disc 7b secured to the motor shaft 6a and four radial partition plates 7a mounted on the disc. Sector-shaped weight members 7c are slidably accomodated in the quadrant spaces defined by the disc 7b, the partition plates 7a and a surrounding cylindrical cup member 7d. The cup member 7d is freely rotatable about the output shaft 6a of the motor, and the outer circumference of each weight member centrifugally contacts or separates from the inner periphery of the cup member. When the motor 6 is energized by a switch (not shown) the disc 7b together with the four partition plates 7a begins to rotate. The weight members 7c also rotate, and move radially outwardly to centrifugally engage the inner wall of the cup member 7d, to thus rotate the latter. 
     FIG. 3 shows an alternate centrifugal clutch mechanism including a rotatable disc member 7b&#39; secured to the motor shaft 6a and a pair of pins 7a&#39; upstanding from the disc. Slots formed in centrifugal weight members 7c&#39; are slidably engaged with the pins 7a&#39; and the output shaft 6a. The functioning of the FIG. 3 construction is identical to that of FIG. 2. 
     Referring again to FIG. 1, a reduction mechanism gear 9 engages a pinion 8 axially secured to the cylindrical cup member 7d, and a smaller gear 32 is coaxially mounted on the gear 9. The smaller gear 32 engages a sector gear 10 pivotally mounted on shaft 10a fixed to the casing 5. The flattened lower end of an actuating rod 11 is pivotally coupled to the sector gear 10 by a connecting pin 12. The flattened upper end of the rod 11 has an elongaged slot 13 in which a pin 14 secured to the end of the lever 2 is slidingly disposed whereby the lever 2 may be moved up and down by the actuating rod 11. The length of the slot 13 is substantially equal to the length of the stroke L of the pin 14 necessary to actuate the lock mechanism 1 via the lever 2. A torsion spring 15 is disposed around the pivot shaft 10a to bias the sector gear 10 toward a neutral position, as shown in FIG. 1. The ends of the spring 15 are freely engaged with the sides of a plate member 16 fixed to the sector gear 10, and extend into a pair of holes or slots 17a, 17b. When the sector gear 10 is in a neutral position the center of the slot 13 is positioned at a level C, which bisects the stroke L of the lever 2. The pin 14 is positioned at the upper end 13a of the slot 13 when the door is unlocked, and at the lower end 13b of the slot 13 when the door is locked. 
     When the motor 6 is deenergized after forward or reverse rotation, the sector gear 10 is restored to its neutral position by the biasing force of the torsion spring 15. A second torsion spring 18 is disposed around the pivot shaft 10a and its protruding ends engage posts 19, 19&#39; at the corners of the casing 5. The spring 18 functions as a damper, whereby the sector gear 10 engages the upstanding ends of the spring to widen it and thus decrease the striking force of the sector gear against the casing 5. Rubber dampers may also be substituted for the spring 18. 
     With this structure, when the door is unlocked, the operator can manually lock it by simply pushing down on the knob 3 and with it the lever 2, whereby the pin 14 moves from the upper end 13a of the longitudinal slot to the lower end 13b thereof. The operator can also manually unlock the door by pulling up on the knob 3 and lever 2, whereby the pin 14 travels from the lower end 13b of the slot 13 to the upper end 13a thereof. In both cases, since the pin 14 moves only between the upper and lower ends of the slot 13, i.e., over the distance L, the movement of the lever 2 is not transmitted to the actuating rod 11, whereby manual operation is not coupled to and does not drive the reduction gear mechanism. 
     In automatic operation, in order to lock the unlocked door the motor shaft 6a is driven counterclockwise (ccw) to centrifugally engage the weight members 7c with the inner wall of the cup member 7d, whereby the sector gear 10 is pivoted downwardly or ccw from its neutral position through the reduction gear 9. This pulls down the actuating rod 11, the pin 14 which engages the upper end 13a of the slot 13, as shown at position A in FIG. 4, and with it the lever 2. One end of the torsion spring 15 engages the lower end of the hole 17b, while the other end of the spring is moved along the hole 17a by reason of its engagement with the plate member 16. Upon completion of the door locking the edge of the sector gear 10 is in contact with the side wall of the casing 5, which prevents the sector gear from further rotation. When the motor 6 is deenergized the sector gear is restored to its neutral position by the torsion spring 15, to thereby raise the slot 13 of the actuating rod 11 to its neutral position (as shown by the solid lines in FIG. 4), whereat the pin 14 contacts the lower end 13b of the slot. Owing to the disengagement of the centrifugal clutch 7, the motor 6 is not rotated during the movement of the sector gear 10 to its neutral position, whereby such movement is easily and rapidly accomplished by the biasing force of the spring 15. 
     On the other hand, in order to unlock the locked door, the motor is driven clockwise (cw) to pivot the sector gear 10 upwardly or cw through the clutch and reduction gear mechanism, to thereby move the actuating rod 11 upwardly. When the door is unlocked the slot 13 is in the position shown at B in FIG. 4. When the motor 6 is deenergized, the centrifugal clutch is disengaged and the sector gear 10 is biased back to its neutral position by the torsion spring 15, which moves the slot 13 to the neutral position at which the pin 14 contacts the upper end 13a of the slot. 
     Any impact that occurs when the sector gear 10 strikes the casing 5 is absorbed by frictional slippage in the clutch 7. Since the distance moved by the actuating rod 11 due to the movement of the sector gear 10 is equal to the stroke L between the door lock and unlock positions, the stroke of the gear 10 is determined to be substantially equal to the length L from the neutral position thereof to either the downward or upward limit of travel. For manufacturing purposes, however, the sector gear swing is designed to be somewhat larger than the stroke L. 
     FIG. 5 shows another embodiment of the invention, wherein the reference numerals designate the same structural elements shown in FIG. 1. Instead of providing an elongated slot 13 at the upper end of the actuating rod 11 as shown in FIG. 1, however, in FIG. 5 an elongated slot 13&#39; is provided in the sector gear 10&#39;. The upper end of the actuating rod 11&#39; is thus pivotally connected to the lever 2 by a pin 20, while the lower end thereof is provided with a pin 14&#39; which is slidably disposed in the slot 13&#39;. The remaining structure and operation is identical to that of FIG. 1, except for the relocation of the motor 6 and reduction gear 9. 
     In the above two embodiments the elongated slot is positioned either in the upper end of the actuating rod 11 or in the sector gear 10&#39;. Alternatively, the slot may be positioned in the lower end of the actuating rod, or directly in the lever 2. That is, the slot may be disposed at any place in the connecting linkage between the lever 2 and the sector gear 10. 
     FIG. 6 shows another embodiment of the invention, wherein one end of the lever 2 is pivotally mounted to the lock mechanism 1 by a shaft 1a, and the other end of the lever 2 is connected to a manual operating knob 3. A sector-shaped linkage member 21 is also pivotally mounted on the shaft 1a, and an actuating rod 11&#34; is pivotally connected thereto. An upper stop projection 22 and a lower stop projection 23 are provided on the linkage member 21, the distance between them being substantially equal to the stroke L of the lever 2 beteen the lock and unlock positions, whereby the lever 2 may slide between the upper and lower projections 22, 23. The structure and functioning of this embodiment is otherwise identical to that of the former embodiments. Alternatively, the manual knob 3 may be connected to the sector-shaped linkage member 21, and the actuating rod 11 connected to the lever 2. 
     FIGS. 7 and 8 show other embodiments of the torsion spring 15 for biasing the sector gear 10 to its neutral position. In FIG. 7 a torsion spring 15&#39; is disposed around the bearing of the pivot shaft 10a, and the upstanding ends of the spring 15&#39; are inserted in an elongated hole 24. The widening of the spring 15&#39; is prevented by a plate 16&#39; attached to the sector gear 10. In this case, only a single hole is required as opposed to the two holes 17a, 17b in the embodiment of FIG. 1. In FIG. 8 a torsion spring 15&#34; straddles the sector gear 10, and its ends are inserted in the holes 17a&#39; and 17b&#39;. With this arrangement the plate 16 and 16&#39; is not required. 
     Instead of providing a torsion spring 15, 15&#39;, or 15&#34; as in FIG. 1, FIG. 7, and FIG. 8, respectively, a coil spring 25 may be disposed around the actuating rod 11, as shown in FIG. 9. The spring 25 is disposed in a housing 26 defined in the upper portion of the casing 5, and the upper and lower ends of the housing have openings to accommodate the actuating rod 11. Upper and lower washers 27, 28 having larger diameters than the rod openings are disposed in the housing to compress the spring 25, and upper and lower stops 29, 30 are fixed to the actuating rod just outside of the upper and lower washers 27, 28, respectively. In operation, when the sector gear 10 is moved upwardly by the energization of the motor, the washer 27 is stopped by the upper wall of the spring housing 26 while the washer 28 is moved upwardly by the stop 30 to compress the spring 25. When the motor is deenergized, the sector gear 10 is pivoted back to its neutral position by the restoring force of the spring 25. 
     FIG. 10 shows a supplemental feature of the invention which may be employed with any of the preceding embodiments, according to which a compression spring 31 is attached to the lever 2 at point 31a. The biasing force of the spring 31 acts in the direction D as shown in FIG. 10. When the pin 14 on the lever 2, the pivot point 2a, and the point 31a are in straight alignment, as shown in FIG. 10, no force is exerted on the lever 2 since the spring 31 does not provide any rotational moment about the pivot point 2a. If the lever 2 is pivoted slightly up or down by the actuating rod, the biasing force of the spring 31 reinforces the pull of the actuating rod 11, but such additional force is largely negated or offset by the frictional forces generated in the lock mechanism 1 when the lever 2 is within an angular range P. If the lever 2 exceeds the range P, however, due to the movement of the actuating rod 11, its rotation is then automatically continued by the force of the spring 31 within a range designated Q to positively lock or unlock the door. The rotation of the motor shaft can therefore be minimized, and limited to a range designated P 1  whereat the spring force becomes sufficiently larger than the frictional resistance of the lock mechanism to sharply complete the locking or unlocking operation.