United States Patent
`
`1191
`
`1111
`
`3,939,339
`
`Alphen
`‘
`[45] Feb. 17, 1976
`
`
`7/I92; Amans ............................... 240/62.2
`1,635,393
`
`ll/194
`H
`h
`240/7.55
`2,335,676
`
`6/I949
`240/62.2
`23,74,610
`Holmes ...... ..
`7/I963
`240/7.55
`3,099,400
`5/1968
`Lemberger ........ ..
`240/62.2 X
`3,385,961
`l/1972
`Stuttgart et al. ............. 240/62.4 X
`3,634,677
`Primary E.\'aminer—L. T. Hix
`Assistant E.ra11ziner—-Alan Mathews
`Attorney, Agent, or Ftrm——Alan I-I. Levine
`~
`'
`'
`ABSTRACT
`
`
`
`[57]
`
`A system for Correction of the Orientation of a’ motor
`Cycle headiamp includes a weight which moves in de_
`pendence on the centrifugaliforce caused by a turning
`movement of the motor cycle. In one embodiment, the
`weight is mechanically linked by transmission chains
`to control the correcting movement of the headlamp.
`In another embodiment, the correcting movement is
`carried out electrically under the control of a trans-
`dueef Whleh Senses the extent Of m0Ve-men‘ 01 the
`welght'
`
`.
`.
`.
`13 C‘“'.'“5’ 9 D"a‘"“g F'g“'°S
`
`[54] LIGHTING SYSTEM FOR A MOTORCYCLE
`,
`[76]
`Inventor:
`Jacques M. Alphen, 67, Allee Jules
`Vemea 92 La Ce11e 531111-Cleuda
`Frallce
`Mar. 28, 1974
`Filed,
`[22]
`[211 APP1- N05 455,757
`
`[30]
`
`Foreign Application Priority Data
`Apr. 2, 1973
`France ............................ .. 73.11767
`
`U.S. Cl. ............................. ..
`Int. CI.2 .......................................... .. B60Q 1/10
`Field 01 Search ---- -- 240/7-55, 3-25, 62 R, 62 A,
`240/62 B, 62 1‘1, 52-1, 62-2, 62-3, 524,
`52-51, 52-61, 62-71
`
`Refefences Cited
`UNITED STATES PATENTS
`11/1911
`Kaufman .......................... .. 240/62.2
`l l/192.0 Whiting
`240/62.2
`
`9/1924
`R€ddil'lg....
`240/62.2
`Hensley ........................... .. 240/62.2
`7/1926
`
`[51]
`[53]
`
`[56]
`
`1,009,973
`l,360,84l
`l.507,203
`1,593,075
`
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`1
`
`KOITO 102
`
`Koito Manufacturing v. Adaptive Headlam
`|PR2016-0007
`
`1
`
`KOITO 1029
`Koito Manufacturing v. Adaptive Headlamp
`IPR2016-00079
`
`

`
`U..S. Patent
`
`I-'3‘eb.17,1976
`
`Sheet1of6
`
`3,939,339
`
`2
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`US. Patent
`
`Feb. 17, 1976
`
`Sheet 2 of 6
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`3,939,339
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`U.S.Patent
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`FIG. 7
`
`Feb.17,1976
`
`5
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`U.S. Patent
`
`Feb. 17, 1976
`
`Sheet5of6
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`U.S. Patent
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`Feb. 17,1976
`
`Sheet6of6
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`3,939,339
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`7
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`

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`1
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`3,939,339
`
`LIGHTING SYSTEM FOR A MOTORCYCLE
`
`BACKGROUND OF THE INVENTION
`
`This invention relates to a lighting system for a motor
`cycle or other similar two-wheeled vehicle. When a
`motor cycle makes a turn, there is a substantial deterio-
`ration in the illumination provided by a standard head-
`lamp,
`the deterioration magnifying in dependence
`upon the speed in which the turn is made. This is princi-
`pally due to the fact that during a turn the cycle is
`physically tilted to compensate for the centrifugal force
`due to the. turn. Such tilting causes the headlamp to be
`tilted and, as a consequence, the beam is tilted as well.
`Moreover, the attitude of the cycle as a whole varies
`slightly due to the centrifugal force affecting the sus-
`pension of the cycle.
`
`SUMMARY OF THE INVENTION
`
`A principal object of the invention is the provision of
`means by which the headlamp of a motor cycle or the
`like has its orientation corrected to an appropriate
`extent as the vehicle makes a turn in one direction or
`the other.
`In accordance with the invention, a system for the
`automatic correction of the orientation of the beam of
`light of the headlamp of a motor cycle or similar vehi-
`cle comprises means for turning at least the optical
`system of the headlamp about an axis of rotation adja-
`cent the optical axis, and a transducer detector system
`adapted to detect the angle of inclination of the vehicle
`while turning, and means for turning the optical system
`of the headlamp being controlled by the transducer
`detector in such a manner that a compensating orienta-
`tion variation is applied to the headlamp beam when
`the vehicle makes a turn.
`The axis of rotation is preferably situated in the cen-
`tral fore and aft plane of the headlamp and is slightly
`inclined forwardly and downwardly in relation to the
`generally horizontal optical axis.
`The means for turning the optical system of the head-
`lamp may comprise a guide ring mounted outside the
`headlamp reflector perpendicularly to the axis of rota-
`tion and cooperating with fixed counterpart elements,
`and a driving toothed ring coaxial with the first ring.
`Conveniently, the transducer detector system com-
`prises a weight capable of moving under the effect of
`centrifugal force and acting directly on a counteracting
`spring system, and means may be provided to hold the
`weight in a top position at times when a correction of
`the orientation of the beam of light is not required.
`A mechanical transmission may be provided com-
`prising at least one rack secured to the weight and
`forming the output member of the transducer. Two
`racks may be provided each of which continuously
`cooperates with a transmission chain terminating in a
`gearwheel adapted to cooperate with the driving
`toothed ring, and means is provided for selective disen-
`gagement of one of the two transmission chains when
`the vehicle makes a- turn. In this case, the selective
`disengagement means may comprise a first circular
`cam track which is fixed with respect to the vehicle
`frame, the center of the circular cam track lying on the
`axis of rotation of a vehicle fork relatively to said
`frame, said cam track cooperating with rollers associ-
`ated with each of the two transmission chains.
`Alternatively, in an electrical system, the transducer
`detector system is associated with a potentiometer
`
`5
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`10
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`15
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`20
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`2
`detector the state of which provides a potentiometer
`value characteristic of the detected centrifugal force,
`and the rotary drive means comprise an electric motor
`whose travel in relation to a mean position is a function
`of the said potentiometer value. The motor is prefera-
`bly a reversible d.c. motor, the direction of rotation of
`which is determined in dependence on the direction in
`which the motorcycle handlebar turns. In this case, the
`reversible motor may be associated with a second refer-
`ence potentiometer which it drives with it, and the
`motor is fed by means of an electric circuit including
`the detector potentiometer and the reference potenti-
`ometer as long as the two potentiometers are not in
`equilibrium inthe said circuit.
`In the light of the above definition, the following
`remarks should be made:
`Where reference is made herein and in the claims to
`means for turning at least the optical system of the
`headlamp it must be understood as meaning at least the
`reflector and the associated lamp and, possibly,
`the
`optical deflectors generally borne by the lens, and it
`should also be understood that the headlamp assembly
`comprising both an optical system and a shell may also
`be turned;
`Generally, the said axis of rotation will be slightly
`inclined downwardly and forwardly in relation to the
`optical axis of the headlamp, the angle of inclination
`being, for example,
`less than 15°. Experiment has
`shown and calculations have confirmed that such an
`inclination gives optimum compensation of the beam in
`the case of motor-cycles generally available on the
`market today. However, other inclinations are possible
`in specific cases without thereby departing from the
`scope of the invention.
`DESCRIPTION OF THE DRAWINGS
`
`The invention may be carried into practice in various
`ways but two specific embodiments will now be de-
`scribed by way of example with reference to the ac-
`companying drawings, in which:
`FIGS. 1, 2 and 3 are diagrams showing the behaviour
`of a motor-cycle when making a turn, FIG. 1 showing
`the lighting of the road, FIG. 2 the inclination of the
`motor cycle on a turn, and FIG. 3 a graph of the applied
`forces;
`FIG. 4 is a diagrammatic side view in partial section
`showing a first embodiment of the system according to
`the invention;
`FIG. 5 is a diagrammatic view of the same system
`from the rear and in partial section;
`FIG. 6 is a top plan view of the transducer detector
`system and of the mechanical transmission system asso-
`ciated therewith;
`FIG. 7 is a diagrammatic perspective view of a trans-
`ducer detector system coupled to a potentiometer in
`accordance with the second embodiment;
`FIG. ‘8 diagrammatically illustrates the headlamp
`control circuit associated with the transducer detector
`system of FIG. 7; and
`FIG.
`is a diagrammatic rear view of the headllamp
`showing the rotary drive thereof.
`DESCRIPTION OF THE PREFERRED
`' EMBODIMENTS
`
`‘ It may be generally stated that the lighting of all such
`vehicles deteriorates when the vehicle makes a turn,
`and such deterioration increases with the speed at
`which the turn is made.
`
`8
`
`

`
`3,939,339
`
`3
`In a typical example, FIG. 1 shows the phenomena in
`perspective. On a straight road with right-hand traffic a
`motor-cycle M moving along the rectilinear path M~Y
`illuminates the road (with a dipped beam) with the rays
`of light situated beneath the cut-off limit G,—A1—D1.
`Such lighting is satisfactory, the headlamp setting hav-
`ing been carried out for an upright vehicle. If, now, the
`same motor cycle M makes a turn to the right, as shown
`by the curved path M—Z, the cut-off limit of its beam of
`light becomes G2—A2—D2. It will be seen that a beam of
`light of this kind is very unsatisfactory. Firstly, its range
`has become inadequate. Secondly,
`its orientation is
`incorrect. G3—A3-D3 shows the optimum cut-off to be
`obtained for the beam of light of the motor-cycle M in
`the righthand turn path M—Z.
`Theoretical and experimental studies have been car-
`ried out to discover the reasons for the phenomenom
`mentioned. It would appear finally that they are due to
`two main causes:
`
`Firstly, it appears that all vehicles of the above type
`in contact with the road at only two points and driven
`at relatively high speeds of several tens of kilometers
`per hour, have the specific characteristic of inclining in
`relation to the plane of the trajectory when making
`turns in order to balance the effect of centrifugal force.
`FIG. 2 shows the behavior of a motor-cycle when mak-
`ing a turn. It will be seen that the central plane C—C of
`the vehicle is inclined by an angle oz to the vertical, the
`angle at being a function of the centrifugal force. More
`accurately, as will be seem from FIG. 3, which is a force
`component diagram, when a weight P is subjected to
`the centrifugal force Fe, the force component P’ de-
`fines the angle 0: in relation to the vertical. In practice,
`with standard-production motor-cycles and under nor-
`mal road traffic conditions, the angle oz may be as much
`as 50°. It will readily be seen that the inclination of the
`vehicle to the vertical is the main cause of the inade-
`quate illumination mentioned. For example, in the case
`of FIG. 1, the angle B of the two halves of the cut-off
`planes A,G,—A2G2 is substantially equal
`to or which
`corresponds to the inclination of the motor-cycle M.
`From another aspect, motor-cycles are usually pro-
`vided with a suspension and a variation of the suspen-
`sion attitude is usually observed when the vehicle
`makes turns, and this is due to the effect of the centrifu-
`gal force applied to the vehicle and results in a relative
`displacement of the suspended part in relation to the
`wheels. The headlamp of such vehicles is rigidly con-
`nected to the suspended part, whether mounted on the
`front pivoting fork of the vehicle (the most general
`case), or on its frame or chassis. Under such conditions
`it appears that the vertical orientation of the beam of
`light from the headlamp follows the variations in the
`attitude of the suspended part, and this second phe-
`nomenon also results in a modification of the distribu-
`tion of the light over the road.
`‘
`Referring to FIGS. 4 and 5 a headlamp shell 1 closed
`at the front by a transparent lens 2 is mounted on the
`fork of a motor-cycle adapted to turn about an axis
`A~A (see FIGS. 4 and 6) in relation to its fixed frame.
`A sealed-beam unit 10 having an axis X-X’ and com-
`prising a reflector 11, a front lens 12 and a lamp (not
`shown) associated with the reflector,
`is mounted for
`rotation about an axis Y—Y’ disposed in the central
`median plane of the headlamp passing through X-X’.
`The axes X-X’ and Y—Y’ intersect at a point advanta-
`geously situated near the light source (filament) of the
`sealed-beam unit, and Y—Y’
`is slightly inclined for-
`
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`4
`wardly and downwardly in relation to X-X’. To this
`end, the reflector 11 bears a movable guide ring 13
`lying perpendicular to Y—Y’ and cooperating with
`three barrel-shaped rollers 14a, 14b, 14c mounted in-
`side the shell 1. Preferably, as illustrated, the three
`rollers are distributed uniformly at 120° intervals in
`relation to the axis Y—Y’; the rollers 14b and 14c are of
`fixed axis and the roller 14a is mounted on a spring 15
`which always tends to push it towards the axis Y—Y’.
`An at least partially toothed ring 16 is also associated
`with the guide ring 11 and is coaxial therewith.
`The transducer detector system 50 will now be de-
`scribed. This system comprises a substantially vertical
`casing 51 inside which a mass 52 (hereinafter referred
`to as a weight) is mounted slidably and bears on a
`resilient system consisting of a plurality of springs 53a,
`53b, 53c. The weight 52 is connectd to two racks 54d
`and 54g projecting through apertures respectively situ-
`ated on the right and left of the casing 51. The springs
`53a, 53b, 53c, are connected in cascade so as to succes-
`sively and cumulatively offer their selected resilient
`resistance to any movement of the weight 52 towards
`the base of the casing 51. Thus when the motor-cycle
`on whose fork the detector 50 is mounted is inclined by
`an angle as on a turn to counterbalance the centrifugal
`force, the racks 54d and 54g undergo a linear displace-
`ment substantially proportional to oz.
`The racks 54d and 54g are designed to cooperate
`with a transmission chain 60d, 60g respectively which
`can in turn cooperate with the toothed ring 16. The
`chain 60d will now be described by way of example.
`It is mounted so as to be slidable between two plates
`70 and 71 (see FIG. 6) connected to the casing 51. It
`comprises essentially a rod 61d provided with two
`shoulders 62d and 63d adapted to abut the plate 70 and
`71 respectively.
`A pinion 64d is mounted at one end of the rod 61d
`and is adapted to cooperate with the toothed ring 16
`when the rod 61d is not pushed rearwardly in the direc-
`tion of the plate 71, as will be apparent hereinafter. In
`its central part the chain 60d comprises a gear 65d
`cooperating continuously with the rack 54d for any
`position of the rod. At its rear end the rod 61d is associ-
`ated with an adjustable link 66d having a roller 67d
`rotatable about a pivot 68d.
`The transmission chain 60g has the same structure
`and has the same references but with the index d
`amended to g.
`The weight 52 is also provided with a notch 52a
`adapted to cooperate with a point 80 on one end of a
`rod 81, two springs 82 always tending to push the point
`80 to the base of the notch 52a. This position is possible
`only when the weight 52 is in the top position corre-
`sponding to straight-line travel. When it is engaged in
`the aperture 52a, the point 80 locks the weight 52 in
`position. A support roller 83 is mounted at the end of
`the rod 81 remote from the point 80. The pivots 68d
`and 68g are connected by a link 90 articulated at 91 on
`the rod 81, the pivots 68d and 68g being adapted to
`slide in slots formed in the link 90.
`
`All the above elements bearing the references from
`60 to 91 are connected to the motor-cycle fork which
`is movable about
`the axis A——A in relation to the
`frame. The casing 51 is advantageously connected to
`the shell as shown. The two transmission chains 60d
`and 60g must cooperate respectively with the tooth
`ring 16 only for a predetermined turn situation (to left
`or right). Also, the weight 52 must be free to slide in
`
`9
`
`

`
`3,939,339
`
`5
`the casing 51 only when the motor-cycle is effectively
`in a turn.
`To this end, a selective disengagement system 100 is
`provided which is connected to the frame and com-
`prises two circular cam tracks 101 and 102, having 5
`their centre on the axis A—-A. The cam track 101 can
`
`cooperate with the two rollers 67d and 67g while the
`cam track 102 cooperates with the roller 83. The cam
`track 101 includes a central part 101a and two side
`parts 101b of smaller radius connected by inclines to 10
`the central part. The cam track 102 has a notch 102a to
`receive the roller 83.
`.
`
`When the motor cycle is travelling in a straight line,
`with the front wheel on the axis of the frame, the sys-
`tem is in the position shown in FIG. 6. The weight 52 is 15
`locked in position by the point 80. The two pinions 64d,
`64g are in mesh with the toothed ring 16.
`When a turn is started, all the elements 1-91 con-
`nected to the fork start to pivot about the axis A—A in
`relation to the elements 100-102 connected to the 20
`frame.
`The first effect of this relative movement is to cause
`
`the roller 83 to leave the notch 10211. The point 80 then
`leaves the notch 52a, thus releasing the weight 52. The
`transducer detector system is thus put into operation.
`The second effect of this relative movement is that
`
`25
`
`one of the rollers 67d, 6_'7g moves towards the centre of
`the central cam track 101a while the other engages one
`of the side parts l01b. The link 90 then pivots about its
`pivot 91. One of the transmission chains 60b and 60g 30
`remains stationary,
`its pinion 64d, 64g remaining in
`mesh with the toothed ring 16 while the other chain
`recedes, its pinion being disengaged from the toothed
`ring 16.
`It will be seen that the movement of the racks trans- 35
`mits a rotary movement in the required direction to the
`optical system, the amplitude of such movement corre-
`sponding, preferably linearly, to the value of the angle
`_
`oz of the inclination of the motor-cycle when the latter
`is in a turn. Thus the beam of light from the headlamp 40
`is systematically corrected.
`.
`Locking of the weight 52 by the point 80 prevents
`any accidental operation of the system outside turns.
`According to an auxiliary feature of the invention, an
`auxiliary electromagnetic control may be used to re- 45
`lease the point 80, such control being actuated only
`when the headlamp is lit; in this way the system accord-
`ing to the invention would remain systematically out of
`operation during the day time and would come into
`operation only when strictly necessary (when turns are 50
`made at night).
`The bottom part of the casing 51 (containing the
`springs 53a, 53b, 53c) forms a chamber closed by the
`bottom part of the weight 52. A small hole 55 enables
`air to escape when the weight 52 descends. This system 55
`forms a pneumatic dash-pot for the movement of the
`weight 52.
`The embodiment according to FIGS. 7-9 will now be
`described.
`The transducer detector 150 in FIG. 7 comprises a 50
`substantially vertical cylindrical casing 151 inside
`which a weight 152 is mounted. The weight is con-
`nected to a rack 154 mounted on a rod 154a projecting
`through the base of the casing. A shaft 155 is mounted
`for rotation on a double frame 156 and a gearwheel 55
`157 keyed on said shaft cooperates with the rack 154
`so that any vertical movement of the weight 152 and of
`the rack 154 results in a rotary movement of the shaft
`
`10
`
`6
`155 which forms the output member of the transducer
`detector 150.
`
`A drum spring 153a is mounted between the shaft
`155 and a fixed point of the frame 156 and tends, like
`the spring 53a, to cause the weight 152 always to move
`towards the top part of the cylinder 15].
`In addition, a damper spring 15311 (having a similar
`function to the spring 53b) may be housed in a recess
`152:: in the weight 152; said spring l53b cooperating
`with the top surface 151a of the cylinder 151 at the end
`of the upward movement of the weight 152; the effect
`of the springs 153a and l53b can therefore be so com-
`bined that the angle of rotation of the shaft 155 is sub-
`stantially proportional to theangle oz of inclination of
`the motor-cycle in a turn.
`A rotary potentiometer 158 is fixed on the frame
`156, its pivot 158a being connected to the shaft 155. It
`will
`readily be seen that
`the potentiometer 158
`mounted in this way converts the value of the angle a
`into a potentiometer value. A potentiometer having a
`linear travel may be used without departing from the
`scope of the invention.
`The use of the detected potentiometer value for the
`compensating drive of the headlamp sealed-beam unit
`by means of an electric motor (FIG. 9) will now be
`explained with reference to the circuit diagram shown
`in FIG. 8.
`’
`
`As previously ‘was the case, the reflector ll of the
`optical system 10 of the headlamp mounted inside a
`shell 1 is movable in respect of rotation about an axis
`Y——Y. To this end, as before, it preferably comprises a
`guide ring 13 cooperating with the rollers 14a, 14b, 14c
`mounted inside the shell 1. The reflector 11 of the
`sealed-beam unit 10 is again provided with a toothed
`ring 16 as in the first embodiment (FIG. 3).
`The rotary drive of the optical system 10 of the head-
`lamp is by means of an electric motor 200 driving the
`toothed ring 16 by means of a gear 170 mounted on the
`shell by means of an assembly yoke 171 (FIG. 9).
`Rotation of the motor 200 must follow the develop-
`ment of the potentiometer value of the potentiometer
`158, the direction of rotation of the motor depending
`upon the direction (left or right) of inclination of the
`motor-cycle handlebar.
`FIG. 8 shows the control circuit used.
`
`This Figure shows certain features of the transducer
`detector system 150 in greater detail. The bottom part
`of the cylinder 151 is formed with an aperture 160
`controlled by a non-retum valve 161. A connecting
`tube 162 connects the outlet of the value 161 to the top
`part of the cylinder 151 externally. A cylindrical rod
`154a extends with practically no leakage through the
`end of the cylinder 151 via a matching aperture 151b;
`a small orifice l51c provides communication between
`the interior and exterior of the cylinder 151. On a
`downward movementof the weight 152 the valve 161 is
`closed and air escapes slowly through the orifice lSlc;
`similarly, the top part of the cylinder 151 fills with air
`only very slowly under the effect of the leakage pas-
`sages formed between the weight 152 and the inner
`wall of the cylinder 151; the descent of the weight 152
`is thus damped; the upward movement of the weight
`152, on the other hand, causes valve 161 to open and
`the bottom and top parts of the cylinder 151 to commu-
`nicate via the connecting tube 162. In these conditions
`there is nothing to oppose the upward movement of the
`weight 152. Such a weight may also be mounted in the
`cylinder 151 by means of ball hearings to reduce fric-
`
`10
`
`

`
`7
`
`3,939,339
`
`10
`
`15
`
`20
`
`25
`
`30
`
`,
`tion.
`Means for locking the weight 152.in its top position
`are also provided. Such means comprise a stud 190
`resiliently urged by a spring 190a andadapted to coop-
`erate by its point 190}; with a notch 196 formed in" the
`weight 152. The stud is formed by a ferro-magnetic
`core and can cooperate with an electrical winding 191
`with which it forms an electromagnet. When the wind-
`ing l91 is energised the stud 190 withdraws and com-
`presses the spring l90a, thus releasing the weight 152.
`The circuit operationally connecting the transducer
`detector 150 to the motor 200 is shown completely in
`FIG. 2 in which reference 300 denotes a switch control-
`ling energization of the headlamp andlpreferably, but
`not necessarily,
`the motor-cycle dipped/main-beam
`switch which controls the electrical supply to the cir-
`cuit which is thus put into operation only when the
`motor cycle headlamp is dipped. The d.c. supply volt-
`age is that of the motor-cycle. Referring to FIG. 8:
`R2’ is a changeover relay;
`158 is the reference potentiometer; to facilitate un-
`derstanding of the invention,
`it is shown both in its
`mechanical position in cooperation with the rack 156,
`and in its electrical position in the electrical circuit
`shown in FIG. 8; the total internal resistance of the
`potentiometer 158 is denoted by resistance R2;
`258 is the rotary potentiometer for giving the posi-
`tion reference of the motor 200. The rotary spindle of
`the potentiometer 258 is connected to the spindle of
`the motor 200. The total internal resistance of potenti-
`ometer 258 is denoted by R6;
`R2, R2, R4, R5, R7, R2, R2, Rm, Ru, RX are resistors;
`C, and C2 are capacitors;
`A, and A2 are amplifiers;
`M,, M2, M2 are microswitches.
`The microswitch M, is controlled by a movable abut-
`ment stud 198 extending through the top part of the
`cylinder 151; when the weight 152 is in its top position,
`it pushes the stud 198 which acts on the microswitch
`M1 to cause it to open (open circuit).
`Microswitches M2 and M2 are controlled by two cam
`tracks 350 and 360 connected to a movable control
`segment 370 adapted to turn with the motor-cycle
`handlebar about the axis A—A. In FIG. 8, segment 370
`is shown with the angular orientation that it has when
`the motor-cycle handlebar is in its mean position corre-
`sponding to straight-ahead travel.
`With the cam track shape shown, it will readily be
`seen that the microswitch M2 is open only for the mid-
`dle position of the handlebar (as shown), and is closed
`when the handlebar is turned to the right or left. It will
`also be seen that the microswitch M3 is open when the *
`handlebar is turned to the left (the start of the opening
`position will be apparent from the Figure) and is closed
`when the handlebar is turned to the right.
`Starting from switch 300, a first arm of the circuit
`enables the winding 191 to be fed both via microswitch
`M, and via microswitch M2. In this way winding 191 is
`always fed except when M, and M2 are open, i.e., when
`the weight 152 is in its top position while the handlebar
`is in its middle position for straight-ahead travel. In the
`latter case, the weight is locked. This locking naturally
`continues when the circuit is not supplied, i._e., when
`the switch 300 is open.
`-.
`,
`The arm of the circuit extending to M2 serves to
`supply the controlwinding of the change—over relay Ri:
`when the microswitch M2 changes its state the relay
`changes over.
`V
`
`35
`
`40
`
`45
`
`50
`
`55
`
`_
`
`60
`
`65
`
`8
`From the switch 300 the main arm of the circuit feeds
`the changeover relay Ri, the two potentiometers 158
`and 258 (detector potentiometer and motor position I
`reference potentiometer respectively), and the two
`amplifiers A1 and A2.
`The potentiometer 158 (total resistance R2) is con- '
`nected in series with R2, R2 and R4. Potentiometer 258
`(resistance R6) is connected in series with R_-, and R7.
`The assembly R1, R2, R4 is fed via relay R1‘ in a direction
`depending on the state of changeover of the relay Ri,
`i.e., the state of microswitch M2. In the first state of the
`relay Ri, the voltage at the slider C2 of potentiometer
`158 varies in a range corresponding to a resistance
`variation ranging from R, to R, + R2. In the other state
`of relay Ri, the voltage at slider c2 varies in a range
`corresponding to a resistance variation ranging from R2
`+ R., to R3 + R4 + R2. The values of the resistance are
`so selected that the said ranges are separate and adja-
`cent so that the voltage at the slider c2 varies continu-
`ously when the motor-cycle handlebar is turned from
`the extreme left to the extreme right. For this R, is
`made equal to R4 and R3 is made equal to R2.
`The reference potentiometer 258 is given the same
`voltage variation hand. For example, R6 = R2 + R2 and
`R5=R7:R1=R4.
`The supply to the motor 200, which is a reversible
`d.c. motor, causes two amplifiers A. and A2 to come
`into operation, each having a non-changeover input a
`and a changeover input b.
`Identical resistors R2, R9, Ru, and R1, are disposed in
`series with each of the said inputs of the two amplifiers.
`The potential difference between the slider c2 (of
`158) and slider es (of 258) is applied to the amplifier A1
`via resistors R3 and R2. This same potential difference is
`also applied, but with an opposite sign, to amplifier A2
`via resistors Rm and R”. In other words, the amplifiers
`A1, A2 are connected similarly but with a change of
`their non-changeover and changeover inputs.
`The capacitors C, and C2 are smoothing capacitors
`which eliminate interference and excess voltage de-
`fects, particularly switching surge voltages. RX is a load
`resistor.
`
`The outputs of the two amplifiers A, and A2 are fed
`to the two terminals of the d.c. motor 200, which ro-
`tates in either direction as long as there is a potential
`difference between C2 and C6. As it moves, motor 200
`drives potentiometer 258 and stops when the two po-
`tentiometers are in equilibrium. The optical system 10
`of the headlamp has then undergone an orientation
`correction corresponding to the potentiometer value
`detected at 158, i.e. corresponding to the angle of incli-
`nation oz of the motor-cycle.
`Of course the present invention is not limited to em-
`bodiments described and illustrated, which are only
`examples.
`' More particularly, the correction system may be used
`in combination with a vertical control system operating
`in dependence upon the vehicle attitude, of any type
`known per se, particularly for motor vehicles, a vertical
`adjustment system of this kind being adapted to control
`the optical system or the shell of the headlamp by add-
`ing its movement to the corrective rotation according
`to the invention. In that case, for example, the head-
`lamp shell is mounted to pivot about a substantially
`horizontal axis. The system according to the invention
`is applicable to any type of motor-cycle, whether or not
`its headlamp is connected to the front fork of the vehi-
`cle. It may be used equally well for correcting main-
`
`11
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`11
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`

`
`10
`9. A headlight according to claim 8 wherein said
`disengaging means includes an arcuate cam fixed with
`respect to the vehicle body, the center of curvature of
`said cam lying on the pivot axis of the vehicle handle-
`bars, and a pair of follower rollers engaging said cam,
`each of said follower rollers being allocated to one of
`said transmissions.
`10. A headlight according to claim 9 including an
`additional arcuate cam fixed with respect to the vehicle
`body, the center of curvature of said additional cam
`lying on the pivot axis of the vehicle handlebars, lock-
`ing means for maintaining said weight against move-
`ment when the vehicle is traveling along a straight path,
`and means for releasing saidlocking means when the
`vehicle handlebars are turned, said releasing means
`including a follower roller engaging said additional
`cam.
`
`11. A headlight according to claim 1 wherein said
`operative means includes a potentiometer, means for
`adjusting the value of said potentiometer in accordance
`with the degree of inclination of the vehicle, a motor,
`and electric circuit means for rotating said motor an
`amount dependent upon the adjustment of said potenti-
`ometer.
`
`12. A headlight according to claim 11 wherein said
`motor is a reversible D.C. motor, and including means
`responsive to the direction in which the vehicle handle-
`bars turn for determining the direction of rotation of
`said motor.
`
`13. A headlight according to claim 12 including a
`reference potentiometer arranged to be adjusted by
`said motor, and wherein said means for rotating said
`motor comprises an electric circuit including both of
`said potentiometers and means for energizing said
`motor until said potentiometers reach equilibrium.
`14. A headlight according to claim 11 including a
`member pivotable with the vehicle handlebars, and
`switch means operable by said member for changing
`the polarity of said potentiometer.
`15. A headlight according to claim 11 including a
`switch for shifting said headlight between a main beam
`and a dipped beam, and means responsive to said
`switch for controlling the power supply to said electric
`circuit means.
`16. A headlight according to claim 11 wherein said
`operative means includes a weight‘ slidably