GB2144796A - Centralised door locking device particularly for motor vehicles - Google Patents

Abstract

A centralised door locking device arranged to enable all the doors of a motor vehicle to be locked simultaneously, and comprising for each door (1) an actuator device (22) in which an electric motor (35) is arranged to rotate the screw (42) of a reversible screw - nut screw unit (36) with ball circulation, of which the nut screw (48), by way of engaging projections (52,58) biassed by elastic means (59), drives a motion transmission element (37) connectable via a rod (21) to the locking lever (12) of a lock (13) of said door (1), to which a manually operated door locking device (10) can be connected. <IMAGE>

Description

SPECIFICATION Centralised door locking device, particularly for motor vehicle doors This invention relates to a centralised door locking device, particularly for motor vehicle doors.

On motor vehicles, and in particular automobiles, it is known to use centralised electromechanical locking devices which are provided with a central control, and of which the operation causes simultaneous locking of all the doors. The said door locking devices of known type are normally associated with a plurality of manually operated door locking devices, each of which is arranged to lock a single door, and they generally comprise for each door a reversible electric motor, the output shaft of which is connected to a rack by way of a spur gear reduction unit. This rack is connected to a lever for locking the latch of the relative door lock, and also to a transmission rod of the relative manual door locking device.Each electromechanical door locking device also supports a microswitch which is operated in one of the end-of-stroke positions of the reduction unit in order to cause reversal of the electricity supply to the electric motor, and thus set this latter to rotate in the opposite direction to the last rotation made.

The aforesaid known centralised door locking devices suffer from certain drawbacks, of which the most important derive from their bulk and their mechanical complexity. In particular the use, in such devices, of racks which are coupled to relative electric motors by way of a reduction unit necessarily requires said motors to be disposed in a transverse position to the relative racks. Such an arrangement normally requires the use of doors of considerable thickness, and generally leads to considerable assembly difficulties.

Moreover, because of the poor mechanical reversibility of the motion transmission linkage constituted essentially by the reduction unit and rack, the devices of known type, being directly connected to the locking lever of the lock latch, lead to an undesirable increase in the minimum force required for operating said latch. A further drawback connected with the poor reversibility of said linkage occurs when the electricity supply to the electric motor fails while the actuator is opening or closing the locking element of the lock. This malfunction is particularly annoying when the lock is locked in its closed state.Finally, it has been found that the end-of-stroke microswitches which are currently used required che provision of a housing compartment, the dimensions of which, taking account of the necessary electrical connectors, are in no way neligible relative to the overall structure of the device, and thus help to increase its bulk.

The object of the present invention is to provide a centralised locking device which is free from the aforesaid drawbacks of devices of known type.

Said object is attained according to the present invention by a centralised door locking device, particularly for motor vehicle doors, which is arranged to allow all the doors of a motor vehicle to be simultaneously locked, and comprises for each of said doors an electromechanical actuator device, the output of which can be associated with the locking element of a relative lock, characterised in that each of said actuator devices comprises: - a reversible electric motor; - a reduction gear device of the screw nut screw type with ball circulation, which itself comprises a screw rigid with the output shaft of said motor and a nut screw; - a motion transmission element which can be connected to said locking element of said lock and is arranged to be driven in two opposing directions by said nut screw between two opposing working positions; and - elastic means which maintain said motion trasmission element connected to said nut screw only during the active translation of this latter induced by the rotary motion which said screw receives from the shaft of said motor.

The present invention will be more apparent from the description of a preferred embodiment given hereinafter by way of non-limiting example with reference to the accompanying drawings, on which: Figure 1 is a diagrammatic sectional view, with parts removed for clarity, of a motor vehicle door provided with a door locking device constructed in accordance with the present invention; Figures 2 and 3 are a front and side elevation respectively of a detail of Figure 1; Figures 4, 5 and 6 are axial sections through the detail of Figures 2 and 3 to an enlarged scale; Figure 7is a section on the line VII-VII of Figures, with some parts removed for clarity; and Figure 8 is a plan view of Figure 5.

Figure 1 shows a motor vehicle door 1 comprising a lower part 2 closed internally by a metal plate 3 rigid with two uprights, of which only the rear one is shown in Figure 1 and is indicated by the reference numeral 4, and further comprising two crossmembers 5 and 6, of which the upperly disposed cross-member 5 lowerly defines a window aperture 7 closed by a window 8.

In the upper cross-member 5 there is slidably mounted an operating pushbutton 9 for a manual door locking device indicated overall by 10 and comprising a rod 11 connected at one end to the lower end of the pushbutton 9 and at its other end to the free end of a lever 12 extending from a lock 13 supported by the upright 4. When in operation, the pushbutton 9 is pushed downwards with conse quentdownward movement of the rod 11,thus rotating the lever 12 in the anticlockwise direction of Figure 1, so that that part thereof which is inside the lock 13 engages with a latch (not shown) of the lock, thus locking this latch in its normal locked position.

A second lever 14 also acts on said latch, and is connected by a tie rod 15 to a handle 16 which, when operated, unlocks the lock 13 and then opens the door 1.

As shown in Figure 1,tithe manual door locking device 10 of known type there is coupled a door locking device of centralised operation indicated overall by 20 and comprising, for each door 1, a transmission rod 21 substantially aligned with the rod 11 and also connected to the free end of the lever 12. The other end of the rod 21 is connected to an actuator device 22, which by means of a centralised control signal is operable together with other similar actuator devices mounted on the other doors, in order to move the rod 21 and thus rotate the lever 12 in one direction or the otherfrom ortowardsits locking position.With particular reference to Figures 1,2 and 3, the actuator device 22 comprises an outer cylindrical casing 24 provided laterally with an outer bracket 25 for its connection to a support block 26 (Figure 1) rigid with the upright 4. The cylindrical casing 24 is closed upperly by a cup-shaped cap 27 which is mounted slidable on said casing 24 and comprises at its upper end an appendix 28 provided with a through transverse hole 29 which when in operation is engaged by an end hook 30 of the rod 21.

In Figures 4,5 and 6 it can be seen that starting from the bottom, the casing 24 internally contains a cover 32 comprising teeth 33 which snap-engage in the lateral walls of the casing 24, the casing 34 of a reversible electric motor 35, a screw- nut screw unit 36 with ball circulation, and a connection element 37 mounted coaxially in the cylindrical casing 24 and partially emerging from this latter in order to snap-engage with the cup-shaped cap 27 by way of respective outwardly projecting toothed end appendices 38.Examining in detail the aforesaid components of the device 22 illustrated in Figures 4,5 and 6, it can be seen that the electric motor 35 comprises a shaft 40 which rests at one end against a wall 41 which is partly embedded in the cover 32, whereas at its other end it is angularly cooupled to the screw 42 of the unit 36, said screw resting at its other end on a respective ball 43 mounted between said screw 42 and the transverse end wall 44 of the cylindrical casing 24. In the screw - nut screw unit 36, the screw 42 externally comprises a helical groove 46 which, together with a corresponding helical groove 47 on the nut screw 48, defines a rolling track for a plurality of balls 49 disposed between the screw 42 and nut screw 48.This latter is constituted by a cylindrical bush 51 preferably of plastics construction and provided on its outer surface with a pair of diametrically opposing radial projections 52. At the opposing ends of the screw 42, two rubber washers 54, 55 are fixed respectively to the casing 34 of the electric motor 35 and to the end wall 44 of the cylindrical casing 24, to prevent the nut screw 48 from violently striking against said casing 34 and end wall 44. The connection element 37 has an essentiallytubular structure, and is mounted coaxially to the screw 42.

Specifically, at the opposite end to the toothed appendices 38, it comprises a pair of notches 56 which internally receive appendices 57, each of which comprises an inwardly pointing tooth 58. At said teeth 58, the connection element 37 comprises a semi-annular groove which houses a corresponding essentially semi-annular flat spring 59, the purpose of which is to keep the ends of the appendices 57 carrying the teeth 58 urged inwards under a predetermined preload. The connection element 37 also comprises, with reference to Figure 7, a longitudinal slot 61 engaged by a plate 62 extending radially from the body of the nut screw 48. The nut screw 48 is therefore guided in the longitudinal direction by the slot 61.

Finally, with reference to Figures 5,7 and 8, the actuator device 22 comprises a T-shaped printed circuit 65 carrying the conducting tracks 66. Specifically, the circuit 65 is contained in a slot partly visible in Figure 5 and provided longitudinally in the casing 24. The conducting tracks terminate at said cover 32 which, as can be seen in Figures 2 and 3, comprises an orthogonal appendix 67 provided with an end tooth 68, the purpose of which is essentially to keep in position and electrical connector (not shown) by means of which the motor 35 is electrically supplied.

One pair of tracks 66 is connected to the windings of the electric motor 35 by conductor cables 71, and an L-bent electrical contact 72 fixed for example by a clinched boss 73 (Figure 7) to the end wall of the connection element 37 slides on a three further tracks 66. The electrical contact 72 comprises a pair of forked appendices 74, the first of which slides constantly on one of the tracks 66 whereas the second slides on one track during a first part of its stroke but on another conducting track 66 during the second part of its stroke. In this mannerthe contact 72 and the respective three conducting tracks 66 overall perform the function of an electrical changeover switch provided with one common contact and a pair of changeover contacts. The operation of the actuator device 22 is described hereinafter with particular reference to Figures 4 to 8.Assuming that said device 22 is in the position shown in Figure 4, the electric motor 35 when supplied with electricity rotates the screw 42 which causes the upward translatory movement of the nut screw 48. This latter drags the element 37 upwards in that the radial projections 52 interfere with the teeth 58 of said element 37. The translatory movement of the element 37 proceeds, as also shown in Figure 6, until it reaches its end-of-stroke position. Underthesecon- ditions, further upward translatory movement of the nut screw 48 causes the appendices 57 of the element 37 to diverge against the action of the spring 59, to cause the projections 52 of the teeth 58 to pass beyond said appendices 57.By virtue of the assembly of the actuator device 22 as shown in Figure 1, the upward translatory movement of the element 37 and thus of the relative cap 27 causes the pushbutton 9 to rise, thus releasing the lock 13 by means of the lever 12. The centralised locking action is also effected by the actuator device 22, by operating the motor 35 such that the shaft 40 of this latter rotates in the opposite direction to the proceeding. Under such conditions, the nut screw 48 drags the element 35 downwards (Figure 6) by virtue of the interference between the projections 52 and the opposing teeth 58 carried by the appendices 57 of said element 37. Again in this case, the downward translatory movement of the element 37 proceeds until this latter reaches the rest position shown in Figure 4, after which the continuation of travel by the nut screw 48 causes the passage of the teeth 58 and the return to the position assumed by said nut screw in Figure 4.

During the course of the translatory movements of the nut screw and relative element 37 in the two directions, the appendices 74 of the electrical contact 72 slide on the conducting tracks 66 of the printed circuit 65. In this manner, when the element 37 is in its opposing working positions, one of the tracks 66 is alternately connected to a second or a third track so as to provide and electrical change-over switch, of which the change-over state is used to feed the electrical supply in the correct directin to the motor 35.

The advantages of the actuator device 22 are apparent from an examination of its characteristics.

Firstly, when in its two opposing working positions shown in Figures 4 and 6 respectively, it transmits practically no additional resistance to the operation of the pushbutton 9 when manually unlocking or locking the lock 13. This is because, with reference to Figures 4 and 6 respectively, the upward or downward movement of the pushbutton 9 causes only the raising or lowering of the element 37 and the respective cap 27 connected thereto, without dragging with it the nut screw 48. In other words, during the manual operation of the pushbutton 9, the actuator device is substantially disengaged.

If the nut screw 48 stops during the middle of its stroke between the opposing rest positions shown in Figures 4 and 6 due to a sudden fault in the electrical supply system of the motor 35, it is necessary only to operate the pushbutton 9 from the outside or the internal handle 16 to transmit to the cap 27, and thus to the element 37 connected thereto, an axial force to the nut screw 48 by way of the appendices 57 of the element 37, to return said nut screw to the required position. This operation is made possible by the fact that the screw nut screw coupling with ball circulation is of the reversible type, and it is therefore only necessary to push the nut screw 48 downwards or upwards in orderto cause it to undergotransla- tory movement in the required direction.

Finally, constructing the said end-of-stroke microswitch by means of the printed circuit 65 and the sliding electrical contact 72 not only reduces bulk but also improves the reliability of the contact itself in that, as is well known, a sliding contact is inherently self-cleaning and thus prevents the formation of oxides on the opposing contact surfaces.

Lastly, it is apparent that modifications can be made to the centralised door locking device 20 and in particular to the electromechanical actuator device 22 without leaving the scope of the present invention.

Claims (9)

1. A centralised door locking device, particularly for motor vehicle doors, which is arranged to allow all the doors of a motor vehicle to be simultaneously locked, and comprises for each of said doors an electromechanical actuator device, the output of which can be associated with the locking element of a relative lock, characterised in that each of said actuator devices comprises: - a reversible electric motor; -a reduction gear device of the screw - nut screw type with ball circulation, which itself comprises a screw rigid with the output shaft of said motor and a nut screw; - a motion transmission element which can be connected to said locking element of said lock and is arranged to be driven in two opposing directions by said nut screw between two opposing working positions; and - elastic means which maintain said motion transmission element connected to said nut screw only during the translation of said nut screw between said opposing working positions.

2. A device as claimed in claim 1, characterised in that said reduction gear device constitutes a coupling of reversible type.

3. A device as claimed in claim 1 or 2, characterised in that said nut screw is essentially constituted by a bush comprising outwardly extending radial projections which cooperate with respective teeth carried at the end of appendices of said motion transmission element.

4. A device as claimed in claim 3, characterised in that said elastic means essentially comprise a semi-annular band which externally embraces said motion transmission element in such a manner as to urge said appendice inwards.

5. A device as claimed in any one of the preceding claims, characterised in that said actuator device comprises a printed circuit mounted parallel to said screw of said reduction gear device; said printed circuit comprising longitudinal tracks on which there slides an electrical contact supported by said motion transmission element.

6. A device as claimed in claim 5, characterised in that the combination of said mobile contact and said conducting tracks overall constitutes an electrical change-over switch.

7. A device as claimed in any one of the preceding claims, characterised in that said motion transmission element is slidable in a cylindrical casing and is coupled at one end to a cup-shaped cap which is arranged to undergo translatory movement on the outside of said cylindrical casing.

8. A device as claimed in any one of the preceding claims, characterised in that the opposing ends of said screw of the reduction gear device, and of the shaft of the motor, rest against respective balls supported by said cylindrical casing.

9. A centralised door locking device, particularly for motor vehicle doors, substantially as described with reference to the figures of the accompanying drawings.