United States Patent
`nu 3,617,731
`__________________________________._____
`[72]
`Inventor
`Jacques Fleury
`Paris, France
`Appl. No. 801,285
`Filed
`Feb. 24, 1969
`Patented
`Nov. 2, 1971s
`Assignee
`Societe Anonyme Automobiles Citroen
`Paris, France
`Feb. 28, 1968
`France
`347 I
`
`[21]
`[22]
`[451
`[73]
`
`[32]
`[33]
`[31]
`
`Priority
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`
`
`[56]
`
`References Cited
`UNITED STATES PATENTS
`
`l/1911 Dunning ..................... ..
`982,803
`3/I922 Brown et al ................. ..
`1,409,661
`3/1924 McVey et al. .............. ..
`1,524,443
`8/1926 Schjotz ...... ..
`1,595,879
`
`4/1967 Yssel ................ ..
`3,316,397
`2/1968 Henry-Biabaud ............
`3,370,162
`9/1968 Hindman .................... ..
`3,402,287
`Primary Examiner——Samuel S. Matthews
`Asrirlaril Exanu'ner—.loseph F. Peters, Jr.
`AlIomey——Arnold Robinson
`
`
`240/8.25
`240/62.2
`240/8.25
`240/41.6
`240/7.1
`240/7.1
`240/7.1
`
`[54]
`
`[52]
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`[51]
`[50]
`
`ADJUSTABLE LIGHTING EQUIPMENT FOR ROAD
`VEHICLE
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`4 Claims, 4 Drawing Figs.
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`240/8.25,
`............... ..
`U.S. Cl.....................................
`240/41.62. 240/61.1, 240/62.3
`Int. Cl....................................................... .. B60q 1/12
`Field of Search .......................................... ..
`240/8.25,
`4l.62,4l.6,7.l,62.3
`
`A road vehicle has head lamps pivotally
`ABSTRACT:
`mounted to illuminate the road round a curve as the vehicle
`moves into the curve. The lamps are also pivotal about
`horizontal axes to compensate for relative height of the vehi-
`cle structure at the front and the rear and also to compensate
`for roll. In a modification a device sensitive to acceleration or
`deceleration is also effective to maintain the lamp beams in a
`preset horizontal plane irrespective of the acceleration or
`deceleration.
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`3,617,731
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`PATENTEDNUV2
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`PATENTEIJNUV2
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`ADJUSTABLE LIGHTING EQUIPMENT FOR ROAD
`VEHICLE
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`BACKGROUND OF THE INVENTION
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`1. Field of the Invention
`This invention relates to road vehicle lighting systems.
`2. Description of the Prior Art
`.
`Adjustment of the throw of headlamps on a motor vehicle is
`made, of course, in relation to the surface on which the vehi-
`cle is standing, in other words in relation to the ground. This
`throw, which should remain constant in relation to the sur-
`face, corresponds, in relation to the vehicle, to an angle which
`varies according to the loading on the front and rear wheel as-
`semblies. Should there be any alteration in static load, this can
`be compensated by adjustment carried out as soon as loading
`is complete, before taking to the road. The same obviously
`cannot apply to changes in dynamic longitudinal loading, aris-
`ing more particularly from the acceleration and deceleration
`of the vehicle or from irregularities in the road surface.
`In French Pat. No. 1,407,221 and the first addition thereto,
`No. 87,233, there is described a device for automatic adjust-
`ment of the throw of the headlamps on a motor vehicle, ir-
`respective of changes in the loads supported by the wheel as-
`semblies of the vehicle, whether these were static loads or
`dynamic longitudinal loads.
`'
`One example of that device specifically described in the first
`patent of addition comprises,
`in conjunction with lamps
`mounted to pivot with respect to the chassis, about a substan-
`tially horizontal axis extending transversely of the vehicle,
`three piston-and-cylinder assemblies in which one member,
`that is to say the cylinder or the piston, is fixed to the chassis of
`the vehicle and the other is movable, the movable member of
`one of the assemblies being connected to the lamps so as to
`cause these to pivot, while the movable members of the other
`two assemblies are connected to members responsive to
`changes in level, relative to the ground, of the front and rear
`respectively of the vehicle, the three cylinders intercommu-
`nicating in such a way as to keep the throw of the lamps con-
`stant, irrespective of the acceleration and deceleration of the
`vehicle.
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`.
`
`When the two arms supporting the front or the rear wheels
`are joined together by an antiroll bar,the member responsive
`to changes in level of that part of the vehicle which is adjacent
`to the wheels concerned may consist of an armed keyed to the
`said bar at an intermediate point in its length.
`Again, when a motor vehicle is travelling at low speed, using
`regulation-type pass lamps, the lighting is sufficiently spread
`to give an adequately wide field of vision. When, on the other
`hand, it is travelling with its main or head lamps on, whether
`these be the normal headlamps or additional long-throw pro-
`jectors giving correct illumination for, high-speed driving on
`the straight, the lighting is far more concentrated, so as to
`carry a long way, and is then often inadequate on bends.
`Vehicles have been proposed in which the lamps are
`mounted to pivot in relation to the car body and are linked to
`the steering so as to pivot at the same time and in the same
`direction as the wheels.
`
`In most of these vehicles with pivotal lamps, the pivot axis is
`vertical. On bends, therefore, the pivot itself, being fixed to
`the car body, sways together with the body as it rolls under
`centrifugal force. The result is that the light beams are raised
`angularly above the horizontal plane.
`To offset this raising of the beams, the pivot pin of each of
`the pivotal lamps may be tilted in a fore-and-aft longitudinal
`plane in relation to the chassis. This longitudinal tilting of the
`axis of the lamp lowers the light beam during a change of
`direction in steering. The angle through which it is lowered by
`this longitudinal
`tilt, however,
`is substantially a parabolic
`function of the pivot angle of the lamp. Consequently, if the
`pivot axes of the lamps be tilted longitudinally by a fixed angle
`to offset the raising due to rolling, in a turn that gives rise to a
`particular centrifugal force, that is to say for a given pivot
`angle of the lamp and a given speed, there will be over-com-
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`pensation if the same turn be taken at reduced speed or under-
`compensation if it be taken at a higher speed. Again, 151 if
`compensation is obtained for a given angle or roll and a given
`pivot angle of the lamp, it will no longer be correct,.for a dif-
`ferent pivot angle, if the angle of roll remains the same.
`In their copending patent application filed under the title
`“Improved lighting equipment for road vehicles,” the present
`applicants describe a vehicle with pivotal lamps in which the
`beams from the lamps can, on the contrary, be maintained at
`the proper level, that is to say substantially horizontal, when a
`bend is being negotiated, whatever be the speed of the vehicle
`and the radius of the bend.
`
`In one example specifically described in that copending
`patent application, the vehicle has a system of headlamps
`mounted to pivot about an axis than can be tilted in a longitu-
`dinal vertical plane, with means whereby these lamps can be
`linked to a part of the steering system so as to cause them to
`pivot according to the change ‘of direction of the wheels, as
`well as two piston-and-cylinder assemblies, one of which va-
`ries the tilt of the pivot axes of the lamps, while the other is
`controlled by a member responsive to the rolling of the vehi-
`cle, the two cylinders intercommunicating so that the said tilt
`varies in proportion to the roll. The device as a whole may be
`supplemented by a further piston-and-cylinder assembly, the
`cylinder of which is in communication with the two previous
`assemblies, this assembly coming into action, when steering
`force is applied to the wheels, to an extent governed by the
`speed of the vehicle.
`The object of the present invention is to provide a vehicle in
`which the lamps pivot in synchronism with the steering and in
`which the pivot axes of these lamps are tilted both in relation
`to roll and to the acceleration and deceleration or to any
`variation in the longitudinal dynamic loading.
`‘
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`SUMMARY OF THE INVENTION
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`According to the present invention there is provided in a
`road vehicle a vehicle structure, two pairs of road wheels, a
`steering system operative to orientate one said pair of road
`wheels, a plurality of lamps each mounted to pivot about a
`respective axis lying in a substantially vertical plane extending
`longitudinally of the vehicle and also to pivot about a substan-
`tially horizontal axis extending transversely of the vehicle,
`means linking the steering system to each lamp whereby steer-
`ing system adjustments cause related pivotal movement of the
`lamps about the said vertical axes, at least three sets of rela-
`tively movable members, each said set including a first said
`member, and a second said member, one said member of each
`set being secured to the vehicle structure and the other said
`member of each set being movable, and said movable member
`of one of the sets being connected to the lamps to cause move-
`ment of the latter about the horizontal axes, devices respon-
`sive to changes in level relative to the ground of the front and
`rear of the vehicle structure, said movable members of the two
`sets of relatively movable members being connected to said
`level responsive devices, fourth set of relatively movable
`members, a device responsive to roll of the vehicle and ar-
`ranged to control the relative positions of the relatively mova-
`ble members of the fourth set, and means providing intercon-
`nection of the four said sets so that, in relation to the vehicle
`structure, the optical axes of the lamps are tilted forward when
`the vehicle rolls and forward tilting is also effected when the
`rear of the vehicle falls relatively to the front thereof and the
`optical axes of the lamps are tilted rearwardly when the rear of
`the vehicle rises relatively to the front thereof.
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`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 is a perspective view of a vehicle incorporating a
`lighting system in accordance with the invention;
`FIG. 2 is a perspective view of part of a modification of the
`system of FIG. 1;
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`FIG. 3 shows a detail of the modification shown in FIG. 2;
`and
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`FIG. 4 shows a modification of the mechanism shown in
`FIG. 3.
`Referring now to the drawings and in particular to FIG. 1
`the vehicle has two lamps 2. Each of these is fixed to a spindle
`3, extending in a substantially vertical longitudinal plane at the
`same time in an axial plane of the lamp, substantially at right
`angles to its optical axis. The top of the spindle 3 is mounted
`by a ball-and-socket joint, 4a, on a part of the frame or
`bodywork 5 of the vehicle. The bottom end of the spindle 3 is
`connected by a ball joint 4b to a short rod 6, which is slidable,
`in relation to the chassis or bodywork, parallel to the fore-and-
`aft line of the vehicle.
`Each of the rods 6 is connected at one end, the front end in
`the case of one of the lamps and the rear end in the case of the
`other, to a piston 7, slidable in cylinder, 8, filled with liquid.
`The two cylinders 8 intercommunicate through a pipe 9, so
`that the rods 6 always move in the same direction and through
`the same distance and thus the pivot axes 3 remain parallel. A
`restoring spring 10, connects one of the rods 6 to the frame,
`chassis, or bodywork 5, its action being to move the rod in the
`direction in which its piston is driven into the corresponding
`cylinder.
`The front wheels 11 of the vehicle are mounted on the ends
`of arms 12, fixed to, and fast for rotation with an antiroll tor-
`sion bar 13, which is free to turn in brackets 14, carried by the
`frame or chassis 5.
`
`Similarly, the rear wheels 15 are mounted on the ends of
`arms 16, fixed to, and fast for rotation with an antiroll torsion
`bar 17, which is free to turn in brackets 18 carried by the
`frame or chassis 5.
`Keyed to the midportion of the anti-roll bar 13 is an arm 19,
`to the free end of which is fixed one end ofa resilient bar 20,
`the other end ofwhich is keyed to the chassis 5.
`An arm 21 keyed to the bar 20 is connected to a piston 22,
`which slides in a cylinder 23, filled with liquid. This cylinder
`23 communicates through a pipe 24 with a second cylinder 25,
`the piston 26 in which is connected to one of the rods 6.
`It will thus be apparent that when the loading on the front of
`the vehicle is increased, for example, the torsion bar 13 turns
`in its brackets 14 and carries with it the arm 19, which in turn
`causes the resilient bar 20, and hence also the arm 21, to turn.
`The piston 22 is driven inwardly in its cylinder 23, causing a
`piston 26 to move outwards from its cylinder 25, carrying with
`it the rod 6 to which it is connected, and thereby varying the
`tilt or inclination of the spindle 3 connected to that rod. The
`linkage is such that the optical axis of the lamp 2 under con-
`sideration is raised. The two rods 6 being linked together by
`the cylinders 8 and pipe 9, the optical axis of the second lamp
`is likewise raised by the same amount.
`The reverse of this action takes place when the loading on
`the front of the vehicle is reduced, the optical axes of the two
`lamps then being tilted forward.
`Similarly, the antiroll bar 17 of the rear axle or suspension
`carries at its center an arm 27, to the free end of which is fixed
`one end ofa resilient bar 28, the other end of which is keyed
`to the chassis or bodywork 5. An arm 29 keyed to the bar 28 is
`connected to a piston 30, slidable in a cylinder 31, which is
`filled with liquid. Contrary, however, to the conditions which
`apply to the front of the vehicle, the mode of assembly is such
`that when the bar 17 turns in consequence of an increase in
`the loading on the rear of the vehicle, the piston 30 is moved
`outwards from its cylinder 31, which communicates through
`the pipe 32 with the pipe 24.
`It will be apparent that an increase in the loading on the rear
`of the vehicle will result in the optical axes of the lamps 2
`being tilted forward, while a reduction in loading will raise
`them.
`The various resilient bars have the same characteristics and
`the cylinders 23 and 31 have the same volumetric capacity, so
`that equal variation in the static loads on the front and rear of
`the vehicle will make no difference to the position of the
`piston 26 and hence to the tilt of the lamps 2.
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`However, a variation in the dynamic longitudinal loading
`will be followed by a change in the tilt of the lamp. For exam-
`ple, should the vehicle accelerate, its front will rise and its rear
`will drop, so that the optical axes of the lamps 2 will be tilted
`forward in relation to the body of the vehicle. Conversely,
`should the vehicle be braked, the optical axes of the projectors
`or long distance lamps will be raised in relation to the body of
`the vehicle, their throw remaining the same at ground level in
`both cases.
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`A short rod 33, is keyed to each spindle 3, the free ends of
`both these rods being pivoted to a single rod 34, which is
`linked to the steering rod system and acted upon by a restoring
`spring 35. When a steering force is applied to the wheels 11,
`therefore, the spindles 3 will be turned in the same direction.
`The method of linking the rod 34 to the steering rod system
`is immaterial, the rod may be connected, for instance, to the
`steering repeater lever, but should preferably be such that
`some conventional mechanism ensures that the pivot angle of
`the lamps 2 is larger than the angle through which the wheels
`are turned and that this pivot angle increases more rapidly at
`the commencement than at the end of the change of direction
`of the wheels.
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`In the example shown, the rod 34 is connected by a cable 36
`slidable within a sheath 37 to a steering repeater lever 38. This
`lever 38, mounted so as to pivot about a pin 39 relatively to
`the chassis 5, is connected by conventional means, through a
`rod 40, to a steering rack 41.
`A cam 42, and a cylinder 43, are mounted on the midpor-
`tion of the rear torsion bar 17, about which they are free to sw-
`ing. This cam and cylinder are connected to the adjacent arms
`16 by rods 44 and 45 respectively. The cam 42 acts in con-
`junction with a cam follower in the form of a roller 46, which
`is carried on a rod 47 rigid with a piston 48. The latter slides
`within the cylinder 43, which communicates through a pipe 49
`with the pipe 32.
`The cam 42 is symmetrical in shape and the roller 46 lies at
`the point of symmetry of the cam in the absence of rolling.
`When the vehicle rolls, the roller 46 rolls on the cam and the
`piston 48 moves outwards from the cylinder 43, so that the
`piston 26 is drawn into the cylinder 25 and lamps 2 are tilted
`forward to an extent governed by the magnitude of the roll
`and determined by the shape of the cam 42, irrespective of the
`direction of the roll.
`As will be evident from the foregoing description, the lamps
`2 are pivot with the wheels 11, but their pivot axes 3 are tilted
`in a longitudinal vertical plane to an extent governed by the
`roll, so that a rise in the light beams is avoided.
`It is also clear that the same assembly of piston 26 and
`cylinder 25 serves to vary the tilt of the pivot axes of the lamps
`2, both in the case of acceleration and deceleration or any
`change in the longitudinal dynamic loading and in the case of
`rolling.
`It is also possible to cause this same piston-and-cylinder as-
`sembly to be acted upon by the device that acts according to
`the speed of the vehicle when steering is applied to the wheels,
`as described in the copending patent application hereinbefore
`referred to.
`Thus, in FIG. 2, the axle or other suspension system of the
`wheels 11, acting through a clutch 81, drives a shaft 70 of a
`centrifugal governor, the axially movable part 71 of which is
`connected to a piston 72. This piston slides in a cylinder 73,
`which is fixed to the chassis 5 and connected by a pipe 74 to
`the pipe 24.
`The clutch 81 is operated by the steering movement of the
`wheels, so that the shaft 70 receives no drive when the wheels
`are directed straight ahead.
`In FIG. 3, a movable plate 81a of the clutch, which is con-
`nected by a cable 82 to the axle of the adjacent wheel 11, is
`biassed towards its “engaged " position by a spring 83, inter-
`posed between the frame 5 and the disc 84 rigidly connected
`to the plate 81a. One end of the lever 85, pivoted at 86 on the
`chassis, bears against this disc 84. The other end of the lever is
`connected by a cable 87, slidable in a sheath 88, to a lever 89,
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`pivoted at 90 on the chassis and held by the spring 83 against a
`central boss 91, on the rack 41.
`When the steering is centralized i.e. the vehicle is travelling
`straight ahead, the lever 85 holds the plate 81a in its inopera-
`tive position through the agency of the disc 84.
`On a turn, on the other hand, the box 91 releases the lever
`89, which turns and causes the plate 810 to be released,
`whereupon the shaft 70 is rotated.
`Should the speed then be increased, the piston 72 moves in
`the cylinder 73 and the optical axes of the lamps 2 are tilted
`forward.
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`In the modification shown in FlG.:4, the cable 87 is fixed to
`a lever 92, rigidly attached to the steering repeater lever 38,
`which releases the disc 84 by means of the cable 87 when the
`road wheels are swung to left or right. It should be emphasised
`that the invention should not be regarded as limited to "the em-
`bodiments described and illustrated, but includes, on the con-
`trary, all variants thereof.
`‘
`lclaim:
`_
`1, ln a road vehicle a vehicle structure, two pairs of road
`wheels, a steering system operative to orientate one said pair
`of road wheels, a plurality of lamps each mounted to pivot
`about a respective axis lying in a substantially vertical plane
`extending longitudinally of the vehicle and also to pivot about
`a substantially horizontal axis extending transversely of the
`vehicle, means linking the steering system to each lamp
`whereby steering system adjustments cause related pivotal
`movement of the lamps about the said vertical axes, at least a
`first, second and third set of relatively movable members, each
`said set including a first said member, and a second said
`member, one said member of each set being secured to the
`vehicle structure and the other said member of each set being
`movable, and means for transmitting movement of said mova-
`ble member of the first set to the lamps to cause movement of
`the latter about the horizontal axes,'a pair of devices respon-
`sive to changes in level relative to the ground, of the respec-
`tive front and rear of the vehicle structure, each one of the
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`said movable members of the second and third set being con-
`nected to one of said level responsive devices, a fourth set of
`relatively movable members, a device responsive to roll of the
`vehicle and arranged to control the relative positions of the
`relatively movable members of the fourth set, and the four
`said sets so that, in relation to the vehicle structure the optical
`axes of the lamps are tilted forward when the vehicle rolls and
`forward tilting is also effected when the rear of the vehicle
`falls relatively to the front thereof and the optical axes of the
`lamps are tilted rearwardly when the rear of the vehicle rises
`relatively to interconnected means for transmitting movement
`of the movable members of said second, third and fourth sets
`to the movable member of the said first set to move the
`headlamps about the said horizontal axis whereby the optical
`axes of the lamps are tilted forward when the vehicle rolls and
`tilted forward when the rear of the vehicle falls relative to the
`front thereof and the optical axes of the lamps are tilted rear-
`wardly when the rear of the vehicle rises relative to the front
`thereof.
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`2. A road vehicle according to claim 1, comprising a fifth set
`of two relatively movable members, one member of the fifth
`set being secured to the vehicle while the other is movable, a
`device responsive to the speed of the vehicle, the movable
`member of the fifth set being operable by said speed-respon-
`sive device means for transmitting movement of said movable
`member of said fifth set to the said interconnecting means to
`tilt the optical axes of the lamps forward when the vehicle
`speed increases and rearwardly when the vehicle speed
`decreases.
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`3. A road vehicle according to claim 2, incorporating means
`whereby the fifth set is inactivated when the vehicle is driving
`straight ahead.
`4. A road vehicle according to claim 1, wherein one
`member of each of said set of relatively movable members
`comprises a cylinder and the other member of each set com-
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`prises a piston slidable in the cylinder.
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