SECURITY LATCHING AND UNLATCHING ACTUATOR AND LOCK FITTED WITH SUCH AN ACTUATOR

Abstract: This actuator comprises an electric motor (1) provided with an output gear which meshes with a toothed wheel (5) rigidly joined to an axial screw (6) which drives a device (11) operating a security latching mechanism, these elements being disposed inside a housing (17) through which the operating devices pass in a leak-tight manner; the screw (6) cooperates with a nut (7) provided with means (8) which block its rotation but allow it to move in translation, and said actuator features a security latching mechanism operating sector (11) which is coaxial with the nut and with the screw and is adapted to be blocked in translation and driven in rotation by said nut rotation blocking means whenever the latter is displaced in translation; the sector is fitted with a seal (15) in the region in which it passes through the housing. This structure offers the advantage of being compact and therefore taking up little space, whilst ensuring excellent leak-tightness thanks to an O-ring (15) between the rotary output sector (11) and the actuator housing (17).

Description: SECURITY LATCHING AND UNLATCHING ACTUATOR AND LOCK FITTED WITH SUCH AN ACTUATOR DESCRIPTION; The present invention relates to a security latching and unlatching actuator for an automotive vehicle door lock, of the type comprising an electric motor provided with an output gear which meshes with a toothed wheel rigidly joined to an axial screw which drives a device for operating a security latching mechanism. These elements are disposed inside a housing through which the operating device passes in a leak-tight manner . A first type of actuator is known in which the toothed wheel and the screw attached thereto drive in translation, through the wall of the housing, a nut-type slider which operates the security latching mechanism. This type of actuator has the advantage of being compact for a given power output and of having a simple structure since it is made up of few parts. Conversely, the leak-tightness of its housing in the region thereof traversed by the nut-type slider, which is provided by a seal, is unsatisfactory on account of the translational mobility of said output part. 'In a second type of conventional actuator, the screw rigidly joined to the toothed wheel carries a nut equipped with a dog point in engagement with the forked end of a connecting arm articulated at its opposing end on an output arm. The leak-tightness of the outlet relies on the two connecting arms being articulated by means of an 0-ring. This actuator provides good leak-tightness on account of its simplicity, but unfortunately it presents the disadvantage that it takes up a large amount of space in directions X and Y. It is therefore the object of this invention to design an actuator configured in such a way as to simultaneously exhibit satisfactory leak-tightness and take up only a small amount of space. In accordance with the invention, the security latching and unlatching actuator for an automotive vehicle door lock is characterised by the fact that the screw cooperates with a nut provided with means which block its rotation but allow it to move in translation, and this actuator features a security latching mechanism operating sector which is coaxial with the nut and with the screw and is adapted to be blocked in translation and driven in rotation by said nut rotation blocking means whenever the latter is displaced in translation, and the sector is fitted with a seal in the region where it passes through the housing. Under a complementary feature, the sector is in the form of a recessed tube terminating in a bore which serves as a trunnion bearing for the screw in cooperation with a second bearing integral with the housing. Such a device takes up only a small amount of space and the fact that its output element is a recessed, exclusively rotational, and cannot be displaced in translation, means that it can be fitted with an O-ring providing excellent sealing performance. According to one form of embodiment of the invention, the bearing for the screw on the side opposing the wheel is set in the sector, and the nut is equipped with laterally protruding fingers engaged in respective volute ramps incorporated in the sector, so that translational movements of the nut cause the sector to rotate about its axis. Further features and advantages of the invention will become apparent from the following description, referring also to the accompanying drawings which illustrate two embodiments thereof by way of non-restrictive examples. Figure 1 is a partial elevational and sectional view showing a first embodiment of the actuator according to the invention. Figure 2 is an elevational view with a partial section in a plane perpendicular to that of Fig. 1. Figure 3 is a cross-sectional view taken along line 3-3 of Fig. 1. Figure 4 is a scaled-up partial perspective view of a second form of embodiment of the security latching and unlatching actuator seen in Figs . 1 to 3. Figure 5 is a perspective view of the actuator seen in Fig . 4 , taken from another angle . The device represented in the drawings is a security- latching and unlatching actuator for an automotive vehicle door lock (not shown) . This actuator includes an electric motor 1 provided with an output shaft " 3 carrying a gear wheel 2 and possibly also a centrifugal clutch 4. The output gear 2 meshes with a toothed wheel 5 rigidly joined to an axial screw 6 equipped with a nut 7 fitted with two laterally protruding fingers 8. The screw 6 and the nut 7 may be disposed on one or the other side of the toothed wheel 5, as respectively represented in Figures 1 and 2 and Figures 4 and 5, reflecting two possible forms of embodiment. The screw 6 is journalled on two bearings 26, 27, one of which is arranged in a housing 17 and the other in the continuation of a bore 28 in a sector 11, on the output side of the actuator. The aforementioned diametrically opposed lateral fingers 8 are engaged in two respective volute ramps 9 incorporated in the cylindrical sector 11, which is disposed coaxially with the screw 6 and with the wheel 5. The sector 11 constitutes the actuator's output device, and actuates an operating pin 14 forming part of a security latching mechanism of the lock (not shown) . Furthermore, the fingers 8 have their respective extremities engaged in corresponding slots 12, which are disposed parallel to the screw 6 in a bracket 13 rigidly joined to the housing 17 supporting the motor 1. The output sector 11 is equipped with an O-ring seal 15 supported by a peripheral collar 16, said seal 15 ensuring leak-tightness with the walls of the housing 17 containing the assembly of parts mentioned already. The elements of the actuator can be displaced with the help of a dog shaft 18 or lock cylinder joined by mechanical means to a security latching and unlatching linkage 19 from the latch, by means of an emergency operating key " (not shown) . The linkage 19 is operatively connected to the sector 11, so that in the event that the electric motor 1 fails, this emergency manual key operation can be used to rotate the sector 11 and actuate its operating pin 14. Depending on the loads at work in the mechanism and the ease with which the key torque is desired to operate, the centrifugal clutch 4 may be dispensed with. Figure 5 shows a possible example of embodiment of the mechanical connection between the linkage 19 and the operating sector 11 : the latter is provided with a rib 22 engaging in a notch 23 disposed in the linkage 19, which likewise features a terminal flat indent 24 which receives a driver 25 rigidly joined in rotation to the lock cylinder 18. It will therefore be seen that when the latter is rotated this causes the driver 25 to turn, which displaces the linkage 19 in translation, and this in turn sets the operating sector 11 rotating by means of its protruding rib 22. The actuator just described may, if appropriate, be arranged inside the same lock housing 17 as a master security locking device, of a type known per se and hence not shown. The method of operation of the foregoing actuator is as follows : When the electric motor 1 is set rotating in one or the other direction, the rotation of its output gear 2 drives the toothed wheel 5 and the axial screw 6. The axial loads due to the meshing of the gear 2 on the toothed wheel 5 are absorbed on the one hand by the bearing 26 disposed in the housing 17, close to the toothed wheel 5, and on the other hand by the bearing 27 forming the ' continuation of the recessed bore 28 in the sector on the output side of the actuator. The nut 7 is prevented from rotating by the fingers 8 sliding in the slots 12. Consequently, the nut 7 can only be displaced in translation along the screw 6, and during this translational movement the lateral fingers 8 slide in the volute ramps 9. This sliding of the dog points 8 in parallel with the axis of the screw 6 therefore rotates the operating sector 11 coaxially with the screw 6 and the wheel 5, which actuates the security latching operating pin 14 in one direction or the other (as arrowed in Figure 4) in response to the direction of rotation of the output sector 11. During these rotational movements by the output sector 11, the leak-tightness between the latter and the housing 17 of the actuator and lock continues to be assured perfectly satisfactorily by the O-ring 15, because the sector 11 is only displaced in rotation and not in translation. Moreover, the actuator mechanism just described can be engineered in a very compact manner, with the result that said actuator simultaneously offers the advantage of a compact structure which takes up little space, capable of receiving or not receiving a centrifugal clutch device 4, and of excellent leak-tightness thanks to the rotary sector 11, to the arrangement of the screw 6 in the housing 17 and the rotary sector 11, and to the O-ring 15. The housing 17 may contain either solely the actuator proper just described, or else said actuator together with the locking and unlocking mechanism of the lock. GLOSSARY = electric motor = output gear = output shaft = centrifugal clutch = toothed wheel = axial screw = nut = finger = volute ramp = output sector = slot = bracket = operating pin = O-ring seal = peripheral collar = housing = dog shaft or lock cylinder = security latching and unlatching linkage = protruding rib = notch = terminal flat indent = driver and 27 = bearing = bore

Claims: CLAIMS 1. Security latching and unlatching actuator for an automotive vehicle door lock, comprising an electric motor (1) provided with an output gear (2) which meshes with a toothed wheel (5) rigidly joined to an axial screw (6) which drives an operating device (11) for a security latching mechanism (14...), these elements being disposed inside a housing (17) through which the operating device passes in a leak-tight manner, characterised in that the screw (6) cooperates with a nut (7) provided with means (8) which lock its rotation but allow it to move in translation, and in that said actuator features a security latching mechanism operating sector (11) coaxial with the nut and with the screw and adapted to be blocked in translation and driven in rotation by said nut rotation locking means whenever the latter moves in translation, and in that the sector is fitted with a seal (15) in the region in where it passes through the housing. 2. Actuator according to claim 1, characterised in that the sector (11) is in the form of a recessed tube terminating in a bore (27) which serves as a trunnion bearing for the screw (6) in cooperation with a second bearing (26) integral with the housing (17) . 3. Actuator according to claim 1, characterised in that the sector (11) is tubular, that the nut (7) is equipped with laterally protruding fingers (8) engaging in respective volute ramps (9) incorporated in the sector, such that translational displacements of the nut (7) cause the sector to rotate about its axis. 4. Actuator according to claim 3, characterised in that the fingers (8) are slidingly engaged in rectilinear guide slots (12) parallel to the screw (6), which slots are formed in a fixed part (13) for example integral with the housing (17) . 5. Actuator according to claim 4, characterised in that the rotary sector (11) is rigidly joined to a security latching operating pin (14) . 6. Actuator according to claim 3 or 4 , characterised in that the operating sector (11) is connected to a security latching and unlatching linkage (19) which cooperates with a dog shaft (18) adapted to be actuated by a manual key. 7. Actuator according to claim 1, characterised in that the output shaft (3) of the motor (1) carries a centrifugal clutch (4) . 8. Automotive vehicle door lock, comprising a locking device and a security latching and unlatching mechanism, these being accommodated in a housing (17) , characterised in that said lock likewise comprises a security latching and unlatching actuator (1, 6, 7, 11, 14...) as claimed in any of claims 1 to 7 , disposed inside the housing.

Inventors: GRANDJEAN RICHARD, GRANDJEAN, RICHARD
Applicants: GRANDJEAN RICHARD, MERITOR LIGHT VEHICLE SYS LTD, GRANDJEAN, RICHARD, MERITOR LIGHT VEHICLE SYSTEMS - FRANCE (ST DIE)
Application year: 1998
Main classification: E05B47
IPC codes: E05B47, E05B65