GB1574493A

GB1574493A - Device for controlling the deflection of motor vehicle headlamps

Info

Publication number: GB1574493A
Application number: GB1688877A
Authority: GB
Original assignee: Daimler Benz AG
Current assignee: Daimler Benz AG
Priority date: 1976-05-12
Filing date: 1977-04-22
Publication date: 1980-09-10
Also published as: FR2350987A1; IT1089856B; FR2350987B1; DE2621054C2; DE2621054A1

Description

(54) DEVICE FOR CONTROLLING THE DEFLECTION OF MOTOR VEHICLE HEADLAMPS (71) We, DAIMLER-BENZ AKTIEN GESELLSCHAFT, of Stuttgart-Untertürkheim, Germany, a Company organised under the laws of the Federal Republic of Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The invention relates to a device for controlling the deflection of motor vehicle headlamps, to modify the range of illumination of the headlamps and which is manually operable from the interior of a motor vehicle.

Such devices provided for manual adjustment are generally known, but have the disadvantage that long adjustment travels are generally necessary in order to adjust the lighting range. This is because firstly, no spontaneous adjustment of the headlamp position must be allowed to occur even when travelling on poor roads, and the large number of return and bearing points produce a heavy auction which can only be compensated by a high transmission ratio.

Because the necessary space for a linear adjustment travel is generally not available, or renders the manipulation too inconvenient, actuation by rotation is adopted, for which, however, rotary angles of up to approximately 900" are required. This, however means that e.g. the marking of headlamp adjustments frequently required is not immediately possible, so that a controller adjustment is rendered extremely difficult.

The invention seeks, in a device of the type initially defined, to achieve by simple means a considerable simplification of the operation and an easier installation.

According to the invention, there is provided an arrangement for varying the deflection of the headlamps of a motor vehicle to alter the range of illumination, comprising a manually operable control unit by which a signal is transmitted through at least one conductor leading from the control unit to a headlamp adjusting means directly connected to the headlamp, wherein the control unit is in the form of an adjustable controller and the headlamp adjusting means comprises at least one servomotor which connects a servo force determined by the position of adjustment of the controller into a predetermined adjustment movement of the headlamps.

Favourable service conditions are obtained if the servomotor is actuated by pressure medium, for example by air under a vacuum.

In one embodiment of the invention, the switch is constructed as a pressure modulator and the control pressure appearing at its output can be fed through a pipe to a control member of the or each servomotor.

Such a device permits an accurate approach to each desired position of headlamp inclination, whilst frictional influences are eliminated due to regulating capacity of the servomotor.

In another embodiment of the invention the switch is constructed as a pressure modulator and the control pressure appearing at its output may be fed through a pipe to at least one single-acting servomotor.

This arrangement is cheaper and generally satisfies requirements. However, frictional influences such as those caused by the bearing of the headlamp mountings, can however have a negative influence upon the precision of adjustment.

In one embodiment of the invention, the controller has a plurality of outputs each corresponding to a position of the controller and the or each servomotor has a corresponding number of associated inputs.

A compact operating and adjusting unit, which can also be provided as a subassembly, is obtained if the controller is provided with a control path such as a cam track by which a control rod of the or each servomotor is adjusted.

Under favourable conditions of installation it may be advantageous if a servomotor is associated with each headlamp.

It is however also possible to provide only one servomotor and to connect the headlamps together by a flexible device transmitting the headlamps adjusting forces.

Embodiments of the invention will now be described more fully and by way of example hereinbelow with reference to the accompanying drawings, in which: Figure 1 shows a first embodiment of the invention with a controller construoted as a pressure modulator and regulating two servomotors.

Figure 2 shows the pressure modulator according to Figure 1 in longitudinal section, Figure 3 shows one of the servomotors according to Figure 1 in longitudinal section, Figure 4 shows another embodiment of the invention with one servomotor and with mechanical transmission of the adjusting movements from one headlamp to the other, Figure 5 shows a third embodiment with two single-acting servomotors for adjusting the headlamps, Figure 6 shows an arrangement according to the invention for providing step-wise adjustment of the lighting range, Figure 7 shows the controller according to Figure 6, in side elevation, Figure 8 shows a section of the controller made along the line VIII-VIII in Figure 7 and Figure 9 shows an embodiment with a servomotor, the regulating means of which is directly influenced by a control path of the controller.

The embodiment of the invention shown in Figures 1 to 3 substantially comprises a command or control unit in the form of a controller 1 which is connected to a vacuum source 2 and is preferably inserted in the instrument panel, not shown, of a motor vehicle. The control pressure obtained as a function of the position of the controller 1 is propagated through a pipe 3 and through a pipe 4 branching from the pipe 3 to a pair of servomotors 5, the diaphragm bar or rod 6 of each of which, extending out of the motor casing, engages a pivotably arranged headlamp 7. The vacuum source 2 employed is the induction maifold 8 of an internal-combustion engine, not shown, from which a pipe 9 leads through a non-return valve 10 and a storage tank or accumulator 11 to the switch 1. A pipe 12 branches from the pipe 9 and leads directly to one servomotor 5, whereas the other servomotor 5 is connected to the vacuum source through a further pipe 13 connected to the pipe 12.

The controller 1 is constructed as a pressure modulator 14 and is acted upon by a crescent-shaped control path or cam track 15, which is part of a pivotably mounted knurled wheel 16. This pressure modulator 14, which is known in principle, has two connections 17 and 18, the connection 17 being connected to the vacuum pipe 9 (Figure 1) and the connection 18 being coupled to the pipe 3. As will be seen from Figure 2, a sealing plate 19 is flexibly supported in the interior of the pressure modulator 14 by means of a peripherally clamped diaphragm 20. By this arrangement two chambers 21 and 22 are created, which can be brought into mutual communication through an annular gap 23 or separated from one another by the part 24 of the diaphragm 20 which is U-shaped in cross section. The chamber 21 is connected to atmosphere.

When the knurled wheel 16 is rotated out of the position illustrated in the direction of the arrow "at", a spring-loaded sensor 25 communicating with the sealing plate 19 is moved in the direction of the pivotal axis 26. The sealing plate 19, which is still sealed with respect to the chamber 21, travels in the same direction and thereby opens a connection through the annular gap 23 to the connection 17. The pressure in the chamber 22 is now reduced until the sealing plate 19 travelling back counter to the pressure of the spring 27 lies in the plane of an atmospheric air inlet (not shown) and the part 24 closes the connection.

Conversely, when the wheel 16 is rotated out of the position illustrated in Figure 2 counter to the direction of the arrow "a?', the sealing plate 19 is moved towards the connections 17 and 18. The part 24 acting as a seal element continues to be braced against the air suction inlet, so that a communication from chamber 21 to chamber 22 is created through the gap 23. This causes the negative pressure in the chamber 22 to decrease until the sealing plate 19, having moved back into its initial position, comes into abutment on the part 24.

These variable negative pressure values are propagated, as shown in Figure 1, through the pipes 3 and 4 to the servomotors 5. Their principle of operation will now be explained more fully with reference to the lower pressure modulator 5 in Figure 1. The variable control pressure is fed, as shown in Figure 3, through the pipe 3 to a first chamber 28 and acts upon a spring-loaded diaphragm or plate 29. The working pressure is fed through the pipe 13 and in turn likewise acts upon a springloaded diaphragm or plate 30 which seals a chamber 31 from a further chamber 32 and which can be connected either to the atmos phere or to the chamber 31 in a manner to be described below.

Attached to the plate 29 is a push rod 33 which is guided by the stem 34 of the diaphragm or plate 30 and its free end 35 acts upon a sprung, clamped, perforated plate 36. Starting from the position shown in Figure 3, if the negative pressure is increased, then the plate 29 moves counter to the pressure of the spring 37 and in doing so carries the push rod 33 the free end 35 of which lifts the perforated plate 36 from the stem 34. This produces a communication of the chamber 31 subject to the work pressure through a channel 38 and an adjoining ring groove 39, a ring gap 40 and a pipe 41 to the chamber 32. This causes the diaphragm or plate 30 and the diaphragm rod 6 attached to it to move to the left until the ring groove 39 is masked by the perforated plate 36 and its orifice is closed by the free end 35 of the push rod 33. By virtue of this feedback, the installation is given a control characteristic, by which friction in the headlamp bearings is compensated.

When the negative pressure in the chamber 28 decreases, the plate 29 and the push rod 33 move to the right, and the free end frees the bore in the perforated plate 36.

The rod 6 is hollow and communicates with the atmosphere at 42 and outside air flows in through the rod 6. This air passes through the ring gap 40 and the pipe 41 into the chamber 32, whereupon the plate 30, and with it the rod 6, moves to the right until the bore in the perforated plate 36 is once again closed by the free end 35 of the push rod 33.

The embodiment shown in Figure 4 operates in the same manner as that of Figures 1 to 3, the transmission of the adjusting movement of the diaphragm rod 6 from the one headlamp 7 to the other occurs by a flexible device 43 which communicates tensile and compressive forces from a single servomotor 5.

The embodiment illustrated in Figure 5 also has a number of common features with the examples hitherto discussed. However, the servomotors 5 used are singleacting, this embodiment having the disadvantage that the bearing friction of the headlamps 7 is not automatically compensated.

In the embodiment shown in Figure 6, the switch 1 fed with negative pressure has an input E and outputs A, B and C, and the servomotor 5 has the same number of inputs, which can be closed selectively by a rolling membrane 44. To this is attached the diaphragm bar communicating the adjusting movements.

The switch 1 in Figure 6 is illustrated more fully in Figures 7 and 8. A knurled wheel 45 mounted pivotably in a housing 44 receives on the side confronting the connections E. A. B and C a guide device 46.

This connects the input E to only one at a time of the outputs A, B and C, or vents the servomotor 5. In the position shown a connection is created from the input E to the output B, whilst the outputs A and C are shut off. As shown in Figure 6, this means that the rolling membrane 44 just masks the associated input. When the wheel 45 (Figure 7) is rotated in the direction of the arrow "b" the guide device 46 pivots with it in the same sense, at first clearing the outputs A, B and C. Because atmospheric air is now admitted, the servomotor 5 (Figure 6) is vented i.e., atmospheric air flows in until the spring 47 has urged the rolling membrane 44 fully upwards. When the knurled wheel 45 is pivoted further in the stated direction, a communication is produced between the input E and the output A, whilst the remaining outputs B and C are masked fluidtightly. The rolling membrane (Figure 6) now moves downwards counter to the pressure of the spring 47 until the next input is just masked.

In the embodiment shown in Figure 9, the switch 1 is provided with a control path 48 bv which a control rod 49 of the servomotor 5 is guided. This control rod 49 corresponds precisely in its function to the push rod 33 in Figure 3 and the remainder of the construction is also comparable, so that the similar parts have identical reference numerals. The diaphragm rod 6 is connected to the device 43 by a member 50 transmitting tensile and compressive forces, so that a compact sub-assembly can be created which can be connected to the headlamps in a simple manner.

WHAT WE CLAIM IS: 1. An arrangement for varying the deflection of the headlamps of a motor vehicle to alter the range of illumination, comprising a manuallyooperable control unit by which a signal is transmitted through at least one conductor leading from the control unit to a headlamp adjusting means directly connected to the headlamps, wherein the control unit is in the form of an adjustable controller and the headlamp adjusting means comprises at least one servo-motor which converts a servo-force determined by the position of adjustment of the controller into a predetermined adjustment movement of the headlamps.

2. An arrangement according to claim 1, wherein the or each servomotor is actuated by a pressure medium.

3. An arrangement according to claim 2, wherein the pressure medium is air under a vacuum.

4. An arrangement according to any one

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. phere or to the chamber 31 in a manner to be described below. Attached to the plate 29 is a push rod 33 which is guided by the stem 34 of the diaphragm or plate 30 and its free end 35 acts upon a sprung, clamped, perforated plate 36. Starting from the position shown in Figure 3, if the negative pressure is increased, then the plate 29 moves counter to the pressure of the spring 37 and in doing so carries the push rod 33 the free end 35 of which lifts the perforated plate 36 from the stem 34. This produces a communication of the chamber 31 subject to the work pressure through a channel 38 and an adjoining ring groove 39, a ring gap 40 and a pipe 41 to the chamber 32. This causes the diaphragm or plate 30 and the diaphragm rod 6 attached to it to move to the left until the ring groove 39 is masked by the perforated plate 36 and its orifice is closed by the free end 35 of the push rod 33. By virtue of this feedback, the installation is given a control characteristic, by which friction in the headlamp bearings is compensated. When the negative pressure in the chamber 28 decreases, the plate 29 and the push rod 33 move to the right, and the free end frees the bore in the perforated plate 36. The rod 6 is hollow and communicates with the atmosphere at 42 and outside air flows in through the rod 6. This air passes through the ring gap 40 and the pipe 41 into the chamber 32, whereupon the plate 30, and with it the rod 6, moves to the right until the bore in the perforated plate 36 is once again closed by the free end 35 of the push rod 33. The embodiment shown in Figure 4 operates in the same manner as that of Figures 1 to 3, the transmission of the adjusting movement of the diaphragm rod 6 from the one headlamp 7 to the other occurs by a flexible device 43 which communicates tensile and compressive forces from a single servomotor 5. The embodiment illustrated in Figure 5 also has a number of common features with the examples hitherto discussed. However, the servomotors 5 used are singleacting, this embodiment having the disadvantage that the bearing friction of the headlamps 7 is not automatically compensated. In the embodiment shown in Figure 6, the switch 1 fed with negative pressure has an input E and outputs A, B and C, and the servomotor 5 has the same number of inputs, which can be closed selectively by a rolling membrane 44. To this is attached the diaphragm bar communicating the adjusting movements. The switch 1 in Figure 6 is illustrated more fully in Figures 7 and 8. A knurled wheel 45 mounted pivotably in a housing 44 receives on the side confronting the connections E. A. B and C a guide device 46. This connects the input E to only one at a time of the outputs A, B and C, or vents the servomotor 5. In the position shown a connection is created from the input E to the output B, whilst the outputs A and C are shut off. As shown in Figure 6, this means that the rolling membrane 44 just masks the associated input. When the wheel 45 (Figure 7) is rotated in the direction of the arrow "b" the guide device 46 pivots with it in the same sense, at first clearing the outputs A, B and C. Because atmospheric air is now admitted, the servomotor 5 (Figure 6) is vented i.e., atmospheric air flows in until the spring 47 has urged the rolling membrane 44 fully upwards. When the knurled wheel 45 is pivoted further in the stated direction, a communication is produced between the input E and the output A, whilst the remaining outputs B and C are masked fluidtightly. The rolling membrane (Figure 6) now moves downwards counter to the pressure of the spring 47 until the next input is just masked. In the embodiment shown in Figure 9, the switch 1 is provided with a control path 48 bv which a control rod 49 of the servomotor 5 is guided. This control rod 49 corresponds precisely in its function to the push rod 33 in Figure 3 and the remainder of the construction is also comparable, so that the similar parts have identical reference numerals. The diaphragm rod 6 is connected to the device 43 by a member 50 transmitting tensile and compressive forces, so that a compact sub-assembly can be created which can be connected to the headlamps in a simple manner. WHAT WE CLAIM IS:

1. An arrangement for varying the deflection of the headlamps of a motor vehicle to alter the range of illumination, comprising a manuallyooperable control unit by which a signal is transmitted through at least one conductor leading from the control unit to a headlamp adjusting means directly connected to the headlamps, wherein the control unit is in the form of an adjustable controller and the headlamp adjusting means comprises at least one servo-motor which converts a servo-force determined by the position of adjustment of the controller into a predetermined adjustment movement of the headlamps.

4. An arrangement according to any one

of claims 1 to 3, wherein the controller is constructed as a pressure modulator and the control pressure appearing at its output is fed through a pipe to the control means of the or each servomotor.

5. An arrangement according to any one of claims 1 to 3, wherein the controller is constructed as a pressure modulator and the control pressure appearing at its output is fed through a pipe to at least one singleacting sermovmotor.

6. An arrangement according to any one of the preceding claims, wherein the controller has a plurality of outputs each corresponding to a position of the controller and the or each servomotor has a corresponding number of associated inputs.

7. An arrangement according to any one of the preceding claims, wherein the controller is provided with a control path by which a control rod of the or each servomotor is adjusted.

8. An arrangement according to any one of the preceding claims, wherein a servomotor is associated with each headlamp.

9. An arrangement according to any one of claims 1 to 7, wherein one servomotor is provided and the headlamps are connected together by a flexible device transmitting the headlamp adjusting forces.

10. An arrangement for varying the deflection of the headlamps of a motor vehicle to alter the range of illumination substantially as hereinbefore described and with reference to Figures 1 to 3 or Figures 1 to 3 modified as shown in Figure 4, Figure 5, Figures 6 to 8 or Figure 9 of the accompanying drawings.