GB2025598A

GB2025598A - Device for adjusting the headlamps of a motor vehicle

Info

Publication number: GB2025598A
Application number: GB7924392A
Authority: GB
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1978-07-13
Filing date: 1979-07-12
Publication date: 1980-01-23
Also published as: JPS5511999A; DE2830752A1; IT1122131B; FR2430872A1; GB2025598B; IT7924271A0

Abstract

A device for adjusting the headlamps of motor vehicles has an electrical drive motor 11 which can move a pivotally mounted headlamp member into a plurality of prescribed pivoted positions by way of a drive mechanism 12-15 and an adjusting spindle 19. An electrical switching device 32, which is described in detail, is provided for controlling the drive motor and has a movable contact carrier 24 which is coupled to the drive mechanism or the adjusting spindle and effects a switching movement upon adjustment of the headlamp from one pivoted position into another pivoted position. The drive motor drives the movable contact carrier 24 non-linearly relative to the adjusting spindle such that, with unequal angles of traverse between the pivoted positions of the headlamp, at least approximately equal adjusting paths of the movable contact carrier ensure. The non-linearity is imparted by a thread 23 of non-uniform pitch on the spindle or by a spiral path on an actuating wheel which are engaged by a pin 29 through the carrier 24. <IMAGE>

Description

SPECIFICATION Device for adjusting the headlamps of a motor vehicle This invention relates to a device for adjusting the headlamps of a motor vehicle. Devices of this kind are controlled by a step switch which is arbitarily actuated or which is actuated in dependence upon the state of load of the vehicle, such that the headlamp is adjustable into a plurality of defined pivoted positions. The task of the switching arrangement of the device is to interrupt the supply of current to the motor when the headlamps have reached the pivoted position prescribed by the step switch.In a known device of this kind (German Offenlegungsschrift 26 37 326), the motor drives the adjusting spindle by way of a cam plate which is mounted on the output shaft of the drive mechanicism on which the movable contact carrier, in the form of a switching disc, of the switching device is also secured. The shape of the cam plate is chosen such that the adjusting movement of the adjusting spindle is proportional to the angular movement of the cam plate and of the contact carrier. This is disadvantageous when the device is used for adjusting headlamps whose individual pivoted positions are unequal distances apart or when the individual adjusting paths for pivoting the headlamps from one pivoted position into the adjacent position are unequal.In these cases, the switching device must also have unequal switching paths between the individual switching positions, so that is it impossible to use commercially available or standardised switches with uniform graduation of the contact travel.

In contrast to this, the device in accordance with the invention has the advantage that with respect to its contact travel, the switching device does not have to be matched to the graduation between the individual pivoted positions of the headlamps, so that it is also possible to use commercially available switches. It is also possible to use one and the same switching arrangement for a plurality of devices having different adjusting path graduations, or to adapt one and the same device to differing requirements merely by changing a member of the drive mechanism.

A compact construction ensues when the drive motor rotatingly drives the adjusting spindle, and the drive for the movable contact carrier of the switching arrangement is derived from the rotary movement of the adjusting spindle.

Advantageously, the adjusting spindle can have a first screw-threaded portion having a uniform small pitch, and a second screw-threaded portion having a non-uniform large pitch, wherein a screw-threaded memberfixed relative to the housing engages the first screw-threaded portion forthe purpose of producing the axial adjusting movement of the adjusting spindle, and an actuating finger, which is mounted so as to be displaceable relative to the housing of the device, but which is non-rotatable, engages the second screw-threaded portion for the purpose of actuating the movable contact carrier.

Hysteresis-free activation of the switching device is obtained when the actuating finger is guided on the second screw-threaded portion ofthe adjusting spindle and is acted upon by a spring which is arranged coaxially of the adjusting spindle and which, irrespective of the direction of rotation of the adjusting spindle, cancels the axial play between the actuating finger and one flank of the thread of the second screw-threaded portion.

In order to relieve the drive from the reaction forces on the member of the headlamp to be pivoted, it is proposed to journal the adjusting spindle in a screw-threaded member which is fixed relative to the housing and which derives an axial adjusting movement of the adjusting spindle from the rotary movement, and to couple the adjusting spindle to the power take-off member of the drive mechanism so as to be non-rotatable relative thereto but axial displaceable. Advantageously, the power take-off member can be a gearwheel or worm wheel which is losely mounted on the adjusting spindle and which has an axial extension having a noncircular bore into which a correspondingly shaped collar on the adjusting spindle engages so as to be displaceable but non-rotatable.

Advantageously, for the purpose of adjusting the device or setting the datum position of the headlamps, the fastening element of the device is constructed so as to be axially adjustable relative to the housing accommodating the operating members of the device.

Two embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure lisa longitudinal section through a device in accordance with the first embodiment of the invention; Figure 2 is a section taken on the line II - II of Figure 1, Figure 3 is an electrical circuit diagram of a headlamp adjusting system which includes the device shown in Figures 1 and 2; Figure 4 is a section through the device in accordance with a second embodiment of the invention; Figure 5 is a section taken on the line V - V of Figure 4, and Figure 6 shows a sub-assembly of the device in accordance with Figures 4 and 5.

Referring now to the drawings, the device illustrated in Figures 1 and 2 includes a support plate 10 to which an electric drive motor 11 is secured. The motor 11 drives a worm 13 by way of a reduction gear 12, the worm 13 meshing with a worm wheel 14 having an external cylindrical extension 15 which is rotatably mounted in the support plate 10. The extension 15 has a bore 16 of hexagonal crosssection profile in which a hexagonal nut 17 is located so as to be axially displaceable but non-rotatable and which is rigidly connected to an adjusting spindle 19. The adjusting spindle 19 has a first screw-threaded portion 20 having a uniform small pitch and which is screwed into a screw-threaded bush 21 formed on the support plate 10.On the opposite side of the hexagonal nut 17, the adjusting spindle 19 is provided with a reduced diameter portion 22 which passes through the worm wheel 14 with play and which carries a second screw-threaded portion 23 having a non-uniform larger pitch and a rectangular thread profile. An actuating finger 24 is slipped on to the screw-threaded portion 23 and has a hub 25 having a smooth bore 26, and two diametrically oppositely located radial extensions 27 and 28. A pin 29 is pressed into the extension 27 and its inner end projects beyond the wall of the bore and engages the screw-thread 23 of the adjusting spindle 19.The extension 27 is guided between bar-like projections 30 on a housing 31 which encloses the drive mechanism, the motor and a switching device 32, further described hereinafter, together with the actuating finger 24 and which serves to support a compression spring 33 acting upon the actuating finger 24.

In order to secure the device to a support wall (not illustrated), there is provided a nut 34 which is displaceably mounted on the bush 21 and which engages the thread of a screw-threaded sleeve 35.

The sleeve 35 has lugs 36 engaging behind a flange 37 of the bush 21 and which is axially fixed relative to the latter. The nut 34 is provided with an annular groove 38 for receiving the edge of a hole in the support wall, wherein a spring washer 39 serves to eliminate the axial play between these two members. The device can be adjusted, or the zero point of the headlamps can be set, by turning the nut 34 relative to the screw-threaded sleeve 35.

Figure 3 shows the electrical circuit diagram of the adjusting system which includes the device of Figures 1 and 2. The switching device 32 has a movable switching contact 40 which co-operates with a contactor 41 comprising four individual contacts 42 to 45 insulated from one another. The insulated portions located between the individual contacts 42 to 45 are dimensioned such that the switching contact 40 is reliably swung downwardly from one individual contact before it comes into contact with the next individual contact. The individual contacts 42 to 45 are connected to a connection terminal 46 which is to be connected to the negative pole of the vehicle battery. The switching contact 40 is connected to the motor 11 by way of symbolically indicated drive means 48.The drive means 48 includes a push rod 49 (Figure 1) which extends out of the housing of the switching device 32 and which is pressed permanently against the actuating finger 24 by means of a spring (not visible).

The connection terminals 50, and 52 are provided on the housing 31 and are connected to the movable switching contact 40 and to the two terminals of the reversible motor 11.

Two push-button swiches 55 and 56 combined to form a structural unit are provided for initiating a pivoting movement, each of which push-button switches has two normally-open contacts 55a, 55b and 56a, 56b respectively. Furthermore, the two push-button switches 55 and 56 act upon a polereversing device for the motor 11, the pole reversing device comprising two change-over contacts 11 a and 11 b which are connectable to the connection terminals 51 and 52 respectively on the housing 31 by way of connection terminals 58 and 59 of the structural unit 54. the two change-over contacts 11 a and 11 bare mounted on an actuating rod 60 which is mechanically controlled by the two push-button switches 55 and 56. The arrangement is such that the actuating rod 60 is displaced into the position shown in Figure 3 upon actuation of the push-button switch 56.The actuating rod 60 is not affected when the push-button switch 56 is subsequently actuated again, so that the change-over contacts 11 a and 11 b remain in their illustrated positions. the actuating rod 60 is displaced to the right upon actuation of the push-button switch 55, wherein the change-over contacts 11 a and 11 b assume their other switching positions and thereby reverse the polarity of the motor 11. The construction illustrated in Figure 3 is only intended symbolically to explain the function and the effect of the push-button swiches 55, 56 upon the change-over contacts 11 a and 11 b. Advantageously, in practice, a construction can be chosen for this purpose in which the two push-button switches 55 and 56 arranged in parallel with one another and act upon a pole-reversing device by way of switching levers orthe like.

The structural unit 54 has a connection terminal 64 which is to be connected to the positive pole of the battery and which is connected to a connection terminal 66 byway of a lead 65 in which are located the normally-open contact r of a relay 67 and the coil of the relay 67. The normally-open contact r of the relay 67 is bridged by the normally-open contacts 55a and 56a of the push-button switches 55 and 56 when the latter swiches are actuated. A switching point 68 between the relay 67 and the connection terminal 66 is connected by way of two branch leads 69 and 70 to a connection terminal 71 of the structural unit 54, the connection terminal 71 being connected to the negative pole of the battery.The branch lead 69 is controlled by the normally-open contact 55b of the push-button switch 55, and the branch lead 70 is controlled by the normally-open contact 56b of the push-button switch 56. Furthermore, the fixed counter-contacts (located on the right in the drawing) of the change-over switches 11 a and 11 b are connected to the connection terminal 71, the other counter-contacts of the change-over switches 11 a and 11 b being connected to the lead 65 between the normally-open contact r and the coil of the rellay 67. The actuating rod 60 prevents the two push-button switches 55 and 56 from being pressed in to theirfull extents. The two push-button switches are each provided with return springs 72 which return the actuating push rod of each the push-button switch to its illustrated initial position after that push-button switch has beert actuated. The actuating rod 60 remains in its position until the other push-button switch is actuated and displaces the actuating rod 60 into its other switching position.

When the parts are in their illustrated positions, the headlamps assume an intermediate position in which the movable switching contact 40 of the switching arrangement 32 rests on the insulated portion between the individual contacts 44 and 45 of the contactor 41. When the switching contact is in this position, the conection between the relay 67 and the negative pole of the battery is interrupted, so that the previously energised relay 67 is de-energised and its normally-open contact r is open. Thus, the supply of current to the motor 11 is also interrupted.

ff the headlamps are now to be pivoted into the adjacent position, the push-button switch 56, for example, has to be actuated, whereby voltage is applied to the relay 67 by way of the normally-open contacts 56a and 56b, and the normally-open contact of the relay 67 closes. The motor then receives current by way of the normally open contact rand the normally open contact 11 a, so that the motor starts and pivots the movable switching contact 40 of the switching arrangement 32 on to the individual contact 45. The push-button switch 56 can then be released. Owing to the fact that the normally-open contact r acts as a self-holding contact, the motor continues to run until the movable switching contact 40 has slid off the individual contact 45 and again interrupts the circuit of the relay 67.If the headlamps are to be pivoted in the other direction, the other push-button switch 55 has to be actuated. The polarity of the motor 11 is then reversed by displacement of the actuating rod 60, and the same switching operations already described above are otherwise initiated. The headlamps are moved by one graduation from the pivoted position into the adjacent position each time one of the push-button switches 55 and 56 is momentarily actuated. Advantageousiy, the switching arrangement 32 can be provided with limit switches (not illustrated) which prevent the circuit of the motor from being closed by one of the push-button switches when the headlamps are in their end positions.

When the motor 11 is switched on, it rotates the spindle 19 by way of the drive mechanism 12 to 14.

The screw-thread in the bush 21 then imparts to the spindle 19 an axial adjusting movement whose magnitude depends upon the pitch of the thread and which has a linear relationship with the angle of rotation of the spindle 19. The actuating finger 24 is at the same time moved in an axial direction byway of the thread 23 in the portion 22 of the spindle and influences the movable switching contact 40 (Figure 3) of the switching arrangement 32. As a result of the fact, already mentioned, that the screw-thread 23 has a non-uniform pitch, a linear relationship no longer exists between the axial travel of the actuating finger 24 and the angle of rotation of the spindle 19, that is to say, the axial adjusting movement of the spindle 19.As a result of this fact, and of the uniform spacing of the individual contacts 42 to 45 of the contactor 41, the adjusting spindle 19 effects axial movements of differing magnitudes upon the switching operations in each case initiated by pressing a button. Thus, in a simple manner, the individual adjustable pivoted positions of the headlamps can be distributed non-uniformlyoverthe entire angle of traverse of the headlamps in conformity with requirements, without having to provide the switching arrangement 32 with a correspondingly non-uniform contact arrangement.

The compression spring 33 ensures that the actuating finger 24 always abuts against the lower flank of the thread 23, so that a specific switching operation is always effected with the spindle 19 in the same position, irrespective of whether the position of the actuating finger 24, corresponding to this switching operation, is reached (approached?) from above or from below. The reaction force exerted upon the spindle 19 by the adjustable member of the headlamp is absorbed by the screwthread of the bush 21, so that the drive mechanism 12to 14andthe electrical switching arrangement 32 are relieved of this force.

Figures 4to 6 show, as a second embodiment, a device which differs from the device of Figures 1 and 2 by virtue of a different mechanical construction of the electrical switching arrangement and by virtue of different means for actuating the switching arrangement. In this device, the non-linear control of the travel of the actuating arrangement 75 is effected by means of an actuating wheel 76 on which is formed a gear wheel 77 which meshes with a gear wheel 78 formed on the worm wheel 14. A control spiral 79 having a non-linear pitch is formed in the actuating wheel 76 and is engaged by an actuating pin 80 of a contact holder 81. The contact holder is rotatably mounted to a pin 82 (Figure 6) which is mounted on a mounting plate 83 secured to three eyes 84 of the support plate 10.

Two resilient contact arms 85 and 86 extend out of the contact holder 81 and co-operate with planar contactors 87 to 89 of the mounting plate 83 which are connected to contact pins 90 which extend outwardly through a cover cap 91 of the device. The actuating wheel 76 is rotated when the motor 11 is running, wherein the actuating pin 80 is deflected radially and the contact holder 81 is pivoted about the pin 82. The contact arms 85 and 86 of the contact holder 81 then slide across the contactors 87 to 89 which are constructed such that the same switching operations ensue as in the device shown in Figures 1 and 2.

Alternatively, the control spiral 79 could be formed directly in the worm wheel 14 when this is possible with regard to the adjusting travel required. The invention is also not limited to co-operation with the electrical switching arrangement of Figure 3. Alternatively, the switching arrangement described in German Patent Application P 28 09 369.8 can be used to advantage.

Claims

1. A device for adjusting the headlamps of a motor vehicle which device comprises an electric drive motor for actuating an adjusting spindle mounted in a housing via a drive mechanism, an electrical switching device for controlling the motor which device includes a fixed contact and at least one movable contact carrier, the movable contact carrier being operable by the drive motor for performing a switching operation upon adjustment of the headlamps through a predetermined angle of traverse, the arrangement being such that the drive motor operates the movable contact carrier for non-linear displacement relative to the adjusting spindle such that approximately equal incremental displacements of the movable contact carrier ensue with unequal angles of traverse between a plurality of pivoted positions of the headlamps.

2. A device as claimed in claim 1, wherein the adjusting spindle is rotatable by the drive motor and the drive for the movable contact carrier of the switching arrangement is derived from the rotary movement of the adjusting spindle.

3. A device as claimed in claim 1 or claim 2, wherein the adjusting spindle includes a first screwthreaded portion having a uniform pitch and includes a second screw-threaded portion have a non-uniform pitch which is large compared to that of the first screw-threaded portion, there being a screw-threaded member secured relative to the housing and engaging the first screw-threaded portion to produce the axial adjusting movement of the adjusting spindle, and there being an actuating finger which is displaceable relative to the housing, but which is non-rotatably mounted, engaging the second screw-threaded portion for actuating the movable contact carrier.

4. A device as claimed in claim 3, wherein the actuating finger is guided on the second screwthreaded portion of the adjusting spindle and is acted upon by a spring mounted coaxially of the adjusting spindle which spring, irrespective of the direction of rotation of the adjusting spindle, eliminates the axial play between the actuating finger and the second screw-threaded portion.

5. A device as claimed in claim 3 or claim 4, wherein the actuating finger includes a hub having a smooth bore receiving the second screw-threaded portion of the adjusting spindle and two diametrically opposed radial extensions, one of which extensions engages between guide bars secured relative to the housing to act as a means for preventing rotation, and the other extension acts upon the movable contact carrier.

6. A device as claimed in claim 5, wherein one of the two radial extensions of the actuating finger carries a pin which engages the screw-thread of the second screw-threaded portion of the adjusting spindle.

7. A device as claimed in one of the preceding claims, wherein the switching arrangement is an independent structural unit having its own housing and an actuating push rod which rod extends out of the housing and is aligned parallel to the adjusting spindle after the switching arrangement has been fitted into the housing of the device.

8. A device as claimed in the adjusting spindle is mounted in a screw-threaded member secured relative to the housing which member derives an axial adjusting movement of the adjusting spindle from the rotary movement, the adjusting spindle being coupled to the power take-off member of the drive mechanism so as to be non-rotatabie thereto but axially displaceable.

9. A device as claimed in claim 8, wherein the power take-off member of the drive mechanism is a worm wheel loosely mounted on the adjusting spindle and which has an axial extension incorporating a non-circular bore which is displaceably but non-rotatable engaged by a collar of complementary configuration located on the adjusting spindle.

10. A device as claimed in claim 9, wherein the collar on the adjusting spindle is a hexagonal nut located on and secured to the first screw-threaded portion of the adjusting spindle.

11. A device as claimed in claim 9 or claim 11; wherein the axial extension of the power take-off wheel of the drive mechanism is rotatably mounted in a bore in the housing.

12. A device as claimed in one of the preceding claims, where in a fastening element of the device is axially adjustable relative to the housing accommodating the operating members for the purpose of adjusting the datum level of the headlamps.

13. A device as claimed in claim 1 or claim 2 or any of claims 8 to 12, wherein the drive motor rotates a cam plate which extends in a plane directed at right angles to its drive axis and has a non-linear radial pitch relative to the drive axis and with which an actuating element acting upon the movable contact carrier co-operates.

14. A device as claimed in claim 13, wherein the cam track is a control spiral which is formed in an actuating wheel and which is engaged by an actuating pin of the contact holder which is pivotally mounted with its axis parallel to that of the actuating wheel.

15. A device as claimed in claim 14, wherein the contact holder is pivotally mounted on a mounting plate which carries planar contactors co-operating with contact arms secured to the contact holder, and connection contact connected to the contactors.

16. A device as claimed in one of claims 13 to 15 wherein the actuating wheel is journalled with its axis parallel to that of a worm wheel which rotates the actuating wheel and a spindle for the purpose of adjusting the headlamps.

17. A device as claimed in claim 13, wherein the cam track in the form of a control spiral is formed directly in a worm wheel which drives an adjusting spindle.

18. A device for adjusting the headlamps of a motor vehicle substantially as hereinbefore described with reference to and as shown in Figures 1 to 3 or Figures 4 to 6 of the accompanying drawings.