United States Patent (19)
`Tsukamoto et al.
`
`USOO6161950A
`Patent Number:
`11
`(45) Date of Patent:
`
`6,161,950
`Dec. 19, 2000
`
`54) VEHICLE HEADLAMP HAVING A
`LEVELING UNIT
`
`6,039,466 3/2000 Duchenne ............................... 362/515
`OTHER PUBLICATIONS
`
`75 Inventors: Michio Tsukamoto; Hirohiko Ohshio,
`both of Shizuoka, Japan
`73 Assignee: Koito Manufacturing Co., Ltd.,
`Tokyo, Japan
`
`WPIAbstract Accession No. 1997-264.723 & JP 090092005
`A (Koito) * Abstract.
`Primary Examiner Sandra O'Shea
`Assistant Examiner H. S. Sawhney
`Attorney, Agent, or Firm Sughrue, Mion, Zinn, Macpeak
`& Seas, PLLC
`21 Appl. No.: 09/382,605
`ABSTRACT
`57
`22 Filed:
`Aug. 25, 1999
`A vehicle headlamp is provided with a leveling unit and a
`30
`Foreign Application Priority Data
`mechanical drive type beam Switching device having one
`actuator mechanism. A low beam is Switched to a high beam
`Sep. 17, 1998
`JP
`Japan .................................. 10-262971
`by driving the actuator of the leveling unit So as to tilt a
`(51) Int. Cl. ................................................ F21V 17/02
`reflector upward by an angle greater than a maximum
`52 U.S. Cl. .......................... 362/513; 362/284; 362/324;
`upwardly-tilted angle at the time of leveling adjustment in
`362/428
`order that the actuator may be set for common use.
`58 Field of Search ..................................... 364,260.272,
`364/277, 282, 285, 386, 418, 512, 513, Met, test EE priety
`514,526, 509, 523, 532, 427
`e reIlector and ulted togeuner W1
`e reIlector up to ine
`aforementioned maximum upwardly-tilted angle on one
`hand, and the bulb holder is fixed to the maximum
`upwardly-tilted angle Separately from the reflector by a
`Stopper pin while the reflector may coincide with a high
`beam upwardly tilting angle.
`19 Claims, 10 Drawing Sheets
`
`56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`4,674,013 6/1987 Manzoni .................................
`5,769,525
`6/1998 Daumueller ..
`... 362/255
`5,911,502 6/1999 Zilgitt .................................... 362/508
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`UNIFIED PATENTS EXHIBIT 1017
`Page 1 of 16
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`U.S. Patent
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`UNIFIED PATENTS EXHIBIT 1017
`Page 2 of 16
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`U.S. Patent
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`Dec. 19, 2000
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`Sheet 2 of 10
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`6,161,950
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`UNIFIED PATENTS EXHIBIT 1017
`Page 3 of 16
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`U.S. Patent
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`Dec. 19, 2000
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`Sheet 3 of 10
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`UNIFIED PATENTS EXHIBIT 1017
`Page 4 of 16
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`U.S. Patent
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`Dec. 19, 2000
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`Sheet 4 of 10
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`UNIFIED PATENTS EXHIBIT 1017
`Page 5 of 16
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`U.S. Patent
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`Dec. 19, 2000
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`Sheet 5 of 10
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`6,161,950
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`FIG. 5A
`
`LOW BEAM
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`HOT ZONE
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`P(H)
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`UNIFIED PATENTS EXHIBIT 1017
`Page 6 of 16
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`U.S. Patent
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`Dec. 19, 2000
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`Sheet 6 of 10
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`6,161,950
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`UNIFIED PATENTS EXHIBIT 1017
`Page 7 of 16
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`U.S. Patent
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`Dec. 19, 2000
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`Sheet 7 of 10
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`6,161,950
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`UNIFIED PATENTS EXHIBIT 1017
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`U.S. Patent
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`Dec. 19, 2000
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`Sheet 8 of 10
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`6,161,950
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`UNIFIED PATENTS EXHIBIT 1017
`Page 9 of 16
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`UNIFIED PATENTS EXHIBIT 1017
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`U.S. Patent
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`Dec. 19, 2000
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`Sheet 9 of 10
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`6,161,950
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`UNIFIED PATENTS EXHIBIT 1017
`Page 10 of 16
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`U.S. Patent
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`Dec. 19, 2000
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`Sheet 10 0f 10
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`UNIFIED PATENTS EXHIBIT 1017
`Page 11 of 16
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`

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`1
`VEHICLE HEADLAMP HAVING A
`LEVELING UNIT
`
`BACKGROUND OF THE INVENTION
`
`1. Field of the Invention
`This invention relates to a vehicle headlamp comprising a
`leveling unit and a mechanical drive type beam Switching
`device.
`2. Description of the Related Art
`Vehicle headlamps are designed to emit low or high
`beams via reflectors which reflect light from light source
`bulbs to a forward point. With respect to light sources
`(discharge light-emitting portions or filaments), though dif
`ferent light Sources are generally used for low and high
`beams, respectively, because the direction of emitting the
`low beam differs from that of emitting the high beam, a
`vehicle headlamp using a single light Source is also well
`known. Particularly in a two-lamp type Vehicle headlamp
`using a discharge bulb as a light Source bulb, a Single light
`Source arrangement is common.
`In the case of a vehicle headlamp using Such a Single light
`Source, a beam Switching device Switches a low beam to a
`high beam, and Vice versa, by mechanically displacing
`optical elements Such as the light Source bulb, the reflector
`and the like.
`In addition, a leveling unit is often provided in the vehicle
`headlamp for preventing a glare from bothering drivers of
`other vehicles. The leveling unit is arranged So that a low
`beam may be emitted in an optimum direction by Vertically
`varying the direction in which the low beam is emitted, in
`accordance with a change in the posture of a vehicle body
`under control. In particular, the necessity of a leveling unit
`is greater when the vehicle headlamp is equipped with the
`discharge bulb that has a greater power than that of a halogen
`bulb or the like.
`When the leveling unit is provided for the vehicle head
`lamp fitted with the beam Switching device mentioned
`above, an actuator is necessary for each of the beam Switch
`ing devices and leveling units.
`In a vehicle headlamp of FIG. 10, for example, a beam
`Switching actuator 104 is required for longitudinally dis
`placing a shade 102, and a leveling actuator 110 is required
`for vertically tilting a reflector 108 coupled to the leading
`end portion of an output rod 106 that has been displaced
`longitudinally. When two actuators are provided like this, a
`problem exists in that the lamp construction tends to be
`complicated, the weight is increased and the lamp becomes
`expensive.
`
`SUMMARY OF THE INVENTION
`In view of the aforementioned situation, an object of the
`present invention is to provide a vehicle headlamp having a
`leveling unit and a mechanical drive type beam Switching
`device, in which the vehicle headlamp leveling and beam
`Switching can be performed with a simple, lightweight,
`inexpensive construction.
`The above object is accomplished by utilizing the actuator
`of the leveling unit for carrying out the beam Switching.
`A vehicle headlamp according to the present invention
`includes a light Source bulb, a reflector for emitting a beam
`with a predetermined light distribution pattern by reflecting
`light from the light source bulb forward, a leveling unit for
`varying the direction of emitting the beam in accordance
`with a change in the posture of a vehicle body by Vertically
`tilting the reflector, and a beam Switching device for Selec
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`tively Switching the beam from a low beam to a high beam,
`and vice versa. The light source bulb is fixedly supported by
`a bulb holder which is vertically tiltably supported by the
`reflector. The beam Switching device operates to Switch the
`low beam to the high beam by driving the actuator of the
`leveling unit So as to tilt the reflector upward by a prede
`termined angle. The beam Switching device also causes the
`bulb holder, together with the reflector, to tilt until the
`upwardly tilted angle of the reflector coincides with a Second
`predetermined angle that is Smaller than the predetermined
`angle at the time of beam Switching, and maintains the bulb
`holder at an upwardly tilting angle that is Smaller than the
`upwardly tilted angle of the reflector after the upwardly
`tilting angle of the reflector exceeds the Second predeter
`mined angle.
`The aforementioned light source bulb is not limited to a
`light Source bulb of a specific kind but may be a discharge
`bulb, an incandescent bulb (including a halogen lamp) or the
`like.
`The aforementioned leveling unit may be an auto leveling
`unit for automatically and vertically varying the direction of
`emitting the low beam in accordance with a change in the
`posture of the vehicle body under control, or a manually
`operated leveling unit for manually and Vertically varying
`the direction of emitting the low beam in accordance with a
`change in the posture of the vehicle body.
`The value of the aforementioned predetermined angle is
`not Specifically limited as long as the value thereof allows
`each of the low and high beam functions to be exhibited by
`the Vertical tilting equal to the predetermined angle.
`AS shown in the aforementioned arrangement, though the
`vehicle headlamp according to the present invention is fitted
`with the leveling unit and the mechanical drive type beam
`Switching device, the light Source bulb is fixedly Supported
`by the bulb holder which is vertically tiltably supported by
`the reflector. The beam Switching device operates to Switch
`the low beam to the high beam by driving the actuator of the
`leveling unit so as to tilt the reflector upward by the
`predetermined angle and the beam Switching device also
`causes the bulb holder, together with the reflector, to tilt until
`the upwardly tilted angle of the reflector coincides with a
`Second predetermined angle that is Smaller than the prede
`termined angle at the time of beam Switching and maintains
`the bulb holder at an upwardly tilting angle that is Smaller
`than the upwardly tilted angle of the reflector after the
`upwardly tilting angle of the reflector exceeds the Second
`predetermined angle.
`Consequently, the beam Switching device operates to
`Switch the low beam to the high beam by driving the actuator
`of the leveling unit so as to tilt the reflector upward by a
`predetermined angle. Also, the beam Switching device
`causes the bulb holder together with the reflector to tilt until
`the upwardly tilted angle of the reflector coincides with a
`Second predetermined angle that is Smaller than the prede
`termined angle at the time of beam Switching, and maintains
`the bulb holder at an upwardly tilting angle that is Smaller
`than the upwardly tilted angle of the reflector after the
`upwardly tilting angle of the reflector exceeds the Second
`predetermined angle. Consequently, the following function
`and effect are achievable.
`Proper leveling control can be performed in the tilted
`angle area of the Second predetermined angle, or Smaller,
`where the bulb holder and the reflector are tilted integrally
`Since the low-beam light distribution pattern is maintained.
`On the other hand, the position of the light source relative to
`the reflector varies in the upwardly tilted angle area of over
`
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`3
`the Second predetermined angle Since the bulb holder is
`maintained at the upwardly tilting angle Smaller than that of
`the reflector, whereby the light distribution pattern is also
`varied. The light Source is relatively displaced on the Slightly
`lower side relative to the optical axis of the reflector then and
`the light distribution pattern is varied into a light distribution
`pattern having a larger portion of upward emission light in
`comparison with what has been established, by Simply
`directing the low-beam light distribution pattern upward.
`Therefore, it is possible to Secure remote visibility Satisfac
`torily during the high-beam driving by using the light
`distribution pattern at the time the reflector is directed
`upward by the predetermined angle as the high-beam light
`distribution pattern.
`The leveling actuator can be used simultaneously as a
`beam Switching actuator by tilting the reflector Separately
`from the bulb holder midway when the reflector is thus tilted
`upward.
`In the vehicle headlamp fitted with the leveling unit and
`the mechanical drive type beam Switching device according
`to the present invention, the leveling and beam Switching
`can be performed with a simple, lightweight, inexpensive
`construction.
`With the above arrangement, the bulb holder may be tilted
`at a tilting angle Smaller than that of the reflector after the
`upwardly tilted angle of the reflector exceeds the Second
`predetermined angle, or the upwardly tilted angle of the bulb
`holder may be fixed to the Second predetermined angle.
`When the latter arrangement is adopted, the lamp can be
`further Simplified in construction.
`BRIEF DESCRIPTION OF THE DRAWINGS
`The above objects and advantages of the present invention
`will become more apparent by describing in detail a pre
`ferred embodiment thereof with reference to the accompa
`nying drawings, in which:
`FIG. 1 is a sectional side view of a first embodiment of a
`vehicle headlamp of the present invention;
`FIG. 2 is detailed side view of an actuator of a leveling
`unit in the first embodiment of the invention;
`FIG. 3 is a sectional side view illustrating the function of
`the first embodiment of the invention;
`FIG. 4 is another sectional side view illustrating the
`function of the first embodiment of the invention;
`FIGS. 5a-5b are diagrams of a light distribution pattern
`illustrating the function of the first embodiment of the
`invention;
`FIG. 6 is a sectional side view of a second embodiment of
`a vehicle headlamp of the present invention;
`FIG. 7 is sectional side view illustrating the function of
`the second embodiment of the invention;
`FIG. 8 is another sectional side view illustrating the
`function of the second embodiment of the invention;
`FIG. 9 is an exploded side view of a bulb-holder sepa
`rating mechanism together with an actuator according to the
`Second embodiment of the invention; and
`FIG. 10 is sectional side view of a conventional example.
`DETAILED DESCRIPTION OF THE
`INVENTION
`Embodiments of the present invention will now be
`described with reference to the drawings.
`FIG. 1 is a sectional side view of a vehicle headlamp
`embodying the first embodiment of the present invention. AS
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`shown in FIG. 1, a vehicle headlamp 10 according to the
`present invention is fitted with a reflector unit 16 in a lamp
`chamber formed by a lens 12 and a lamp body 14 so that the
`reflector unit 16 is tiltable in the vertical and lateral direc
`tions.
`The reflector unit 16 includes a light Source bulb (e.g., a
`metal halide discharge bulb) 18, a bulb holder 40 (which will
`be described hereinafter) for fixedly Supporting the light
`Source bulb 18, a reflector 20 for tiltably supporting the bulb
`holder 40 around a fulcrum A, and a shade 22 fixedly
`supported by the bulb holder 40 so as to surround the light
`Source bulb 18 within a predetermined range.
`The lens 12 is a See-through lens and together with the
`reflector unit 16, controls light distribution. More
`specifically, the reflector 20 is fitted with a reflective surface
`20a for forwardly reflecting light from a discharge light
`emitting portion 18a of the light source bulb 18, and the
`diffusing, deflecting, and reflecting functions of the reflec
`tive Surface 20a are utilized for the emission of beams
`having a light distribution pattern as will be described
`hereinafter.
`The reflector 20 is supported with the lamp body 14 via
`aiming screws 24 at brackets 20b, each formed in both
`lateral upper end portions of the reflector 20 and also
`supported with the lamp body 14 via an actuator 28 of a
`leveling unit 26 at a bracket 20c formed in the lower right
`end portion (or the upper left end portion) of the headlamp
`10.
`As shown in FIG. 2 in detail, the actuator 28 includes an
`actuator body 30 fixedly supported by the lamp body 14, and
`an output rod 32 projecting forward from the actuator body
`30. A spherical leading end portion 32a of the output rod 32
`is coupled to the bracket 20c of the reflector 20.
`A leveling controller 34 of the leveling unit 26 causes the
`actuator 28 to be driven as the posture of a vehicle body
`varies, and by displacing the output rod 32 longitudinally,
`the leveling controller 34 makes the reflector unit 16 tilt
`vertically with the point A as a fulcrum and with a point B
`as a point of application in FIG. 1, to maintain the optimal
`direction of the emitted beam at all times as the posture of
`the vehicle body varies. In this case, this leveling control is
`not performed during the high-beam driving but performed
`during the low-beam driving.
`The adjustment of the optical axis Ax of the reflector unit
`16 is made by adjusting the aiming Screw 24 So that the
`output rod 32 of the actuator 28 is set at a reference leveling
`position L. The axis adjustment is intended to direct the
`optical axis Ax of the reflector 20 downward by 0.57
`relative to the horizontal direction and when the optical axis
`adjustment is completed, there can be provided a low-beam
`light distribution pattern P (L) having a clear cutoff line (a
`light-to-shade boundary line) CL with its horizontal line
`portion positioned at 0.57 as shown in FIG. 5(a). The tilted
`angle position of the reflector 20 is hereinafter called a
`“reference leveling angle position.”
`A multiple closed curve shown by a solid line in the light
`distribution pattern P(L) indicates Zone divisions that are
`irradiated in Such a manner that the inner ones are made
`gradually brighter; that is, the central Zone shown by Slant
`ing lines is the brightest hot Zone.
`AS shown in FIG. 2, a leveling adjustment range R is Set
`so that when the output rod 32 is displaced up to the front
`end position of the leveling adjustment range R, the reflector
`20 is directed upward by 2 relative to the reference leveling
`angle position in one Stroke, whereas when the output rod 32
`is displaced up to the rear end position of the leveling
`
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`adjustment range R, the reflector 20 is directed downward by
`3 relative to the reference leveling angle position therein.
`The leveling unit 26 also functions as a beam Switching
`device, for performing not only the leveling control as
`mentioned above, but also Switching of the beam between
`low and high beams. Consequently, a beam Switching Signal
`is inputted to the leveling controller 34 from a beam
`changeover Switch 36.
`AS mentioned above, the leveling control is carried out by
`displacing the output rod 32 of the leveling unit 26 within
`the leveling adjustment range R. When a high-beam Switch
`ing Signal is inputted to the leveling controller 34 from the
`beam changeover Switch 36, the output rod 32 is displaced
`up to a high-beam Switching position H, ahead of the front
`end position of the leveling adjustment range R, to have the
`reflector unit 16 tilted up to an angle position of 3 upward
`relative to the reference leveling angle position, whereby the
`low beam is Switched to the high beam.
`As shown in FIG. 1, the bulb holder 40 is formed with a
`tilting bracket 4.0a in its upper end portion and an L-shaped
`bracket 40b in the lower end portion. The upper end portion
`of the tilting bracket 4.0a is coupled to a holder Supporting
`bracket 20e formed in the upper part of the optical axis AX
`in the back of the reflector 20 with a pin, so that the bulb
`holder 40 is tiltably supported around the fulcrum A with
`respect to the reflector 20.
`On the other hand, the lower end portion of the L-shaped
`bracket 40b is linked with a tab 20f formed in the lower back
`end portion of the reflector 20 via a tension Spring 42 So as
`to bring the bulb holder 40 into contact with the rear opening
`20d of the reflector 20 by resiliently urging the bulb holder
`40 forward. A stopper-pin inserting hole 40c is formed in the
`intermediate portion of the L-shaped bracket 40b, so that a
`Stopper pin 44 extending longitudinally is inserted therein.
`The stopper pin 44 is screwed into a boss portion 14b
`formed in the rear wall portion 14a of the lamp body 14, and
`a driver mating groove 44a is formed in the rear end portion
`of the Stopper pin 44. Further, the Stopper pin 44 is made
`displaceable longitudinally by operating a driver. The front
`end portion of the Stopper pin 44 is formed into a spherical
`portion 44b and when the L-shaped bracket 40b undergoes
`a predetermined amount of forward displacement with
`respect to the Stopper pin 44, the Spherical portion 44b is
`brought into contact with the L-shaped bracket 40b, so that
`the L-shaped bracket 40b is stopped from being displaced
`forward further. In this case, the front-end peripheral edge
`portion of the inserting hole 40c in the front of the L-shaped
`bracket 40b is made spherical so that the L-shaped bracket
`40b is smoothly brought into contact with the spherical
`portion 44b.
`The position where the stopper pin 44 is screwed into the
`lamp body 14 is set as follows. When the optical axis of the
`reflector unit 16 is adjusted, the Stopper pin 44 is displaced
`sufficiently forward beforehand so that it may not hamper
`the optical axis adjustment. The output rod 32 of the actuator
`28 is displaced up to the front end position of the leveling
`adjustment range R after the optical axis adjustment is
`completed and the Stopper pin 44 is displaced backward in
`this State. Then the Stopper pin 44 is stopped in the position
`where the spherical portion 44b of the stopper pin 44 has
`been brought into contact with the L-shaped bracket 40b
`lightly.
`In Such a State that the Stopper pin 44 has thus been
`positioned, the bulb holder 40 and the reflector 20 are tilted
`together within the leveling adjustment range R. FIG. 3
`shows a situation in which the output rod 32 has been
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`displaced up to the front end position of the leveling
`adjustment range R and the reflector 20 has been directed
`upward by 2 relative to the reference leveling angle posi
`tion as indicated by AX'.
`When the low beam is switched to the high beam,
`however, the output rod 32 is displaced up to the high-beam
`Switching position H ahead of the front end position of the
`leveling adjustment range R. As shown in FIG. 4, the bulb
`holder 40 is brought into contact with the stopper pin 44 and
`fixedly directed upward by 2 relative to the reference
`leveling angle position, whereas only the reflector 20 con
`tinues to be tilted up to the tilt angle position where it is
`directed upward by 3 relative to the reference leveling
`angle position as indicated by AX". At this time, the light
`Source bulb 18 together with the bulb holder 40 is relatively
`tilted downward by 1 around the fulcrum A relative to the
`reflector 20, whereby the discharge light-emitting portion
`18a of the light source bulb 18 is displaced downwardly
`relative to the optical axis Ax of the reflector 20 (see FIG.
`3).
`FIG. 5(b) shows a light distribution pattern for the high
`beam P(H) when the reflector 20 is directed upward up to the
`tilt angle position for the high beam.
`Unlike the light distribution pattern for the low beam P(L)
`which has been directed upward by 3 as shown in FIG. 5(a),
`the light distribution pattern P(H) is a light distribution
`pattern capable of making remote visibility Satisfactorily
`Secured during the high-beam driving, because light con
`vergence toward H-V (in the direction of the right front of
`the lamp) becomes increased and because the cutoff line CL
`is practically eliminated by displacing the discharge light
`emitting portion 18a of the light source bulb 18 downwardly
`relative to the optical axis AX (see FIG. 4).
`As set forth above in detail, the high-beam light distri
`bution pattern is not established only by directing the
`low-beam light distribution pattern upward, Since the reflec
`tor 20 is tilted separately from the bulb holder 40 after the
`reflector 20 is tilted past a certain point, according to this
`embodiment of the invention. By achieving a light distribu
`tion pattern excellent in remote visibility with a larger
`portion of upward emission light, the leveling actuator 28
`can be used simultaneously as a beam Switching actuator.
`Therefore, according to this embodiment of the invention,
`the leveling as well as beam Switching can be carried out
`with a simple, lightweight and inexpensive construction.
`A second embodiment of the invention will now be
`described.
`FIG. 6 is a sectional side view of a vehicle headlamp
`embodying the present invention. AS shown in FIG. 6, a
`vehicle headlamp according to this embodiment of the
`invention is substantially similar to that in the first embodi
`ment thereof, except the basic construction of the lamp is
`concerned with a bulb-holder Separating mechanism 46 for
`separating the bulb holder 40 from the reflector 20 when the
`reflector 20 is tilted upward, and when the low beam is
`Switched to the high beam, it is localized close to the output
`rod 32 of the leveling actuator 28.
`The actuator 28 according to this embodiment of the
`invention is a rotary drive type actuator that causes the
`output rod 32 to be pivoted in a predetermined angle range.
`The bulb-holder Separating mechanism 46 comprises an
`inner cylindrical cam 48 and an outer cylindrical cam 50
`which are fitted to the output rod 32 of the actuator 28. The
`inner cylindrical cam 48 is coupled to the bracket 20c of the
`reflector 20, whereas the outer cylindrical cam 50 is coupled
`to the L-shaped bracket 40b of the bulb holder 40. Cam
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`UNIFIED PATENTS EXHIBIT 1017
`Page 14 of 16
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`7
`grooves 48a and 50a mating with pins 32b provided on the
`output rod 32 fit in these inner and outer cylindrical cams 48
`and 50, respectively. These inner and outer cylindrical cams
`48 and 50 are driven by the actuator 28 integrally and
`longitudinally within the leveling adjustment range when the
`output rod 32 is pivotally driven. When the reflector 20 is
`tilted upward beyond the leveling adjustment range, only the
`inner cylindrical cam 48 is moved longitudinally while the
`outer cylindrical cam 50 stands still, so that only the reflector
`20 is tilted upward.
`FIG. 7 is a sectional side view showing a state in which
`the output rod 32 is pivotally displaced up to one pivotal end
`of the leveling adjustment range, which results in directing
`the reflector 20 upward by 2 relative to the reference
`leveling angle position. FIG. 8 is a Sectional Side view
`showing a State in which the output rod 32 is pivotally
`displaced up to the high-beam Switching position beyond the
`aforementioned pivotal end of the leveling adjustment
`range, which results in directing the reflector 20 upward by
`3 relative to the reference leveling angle position.
`FIG. 9 is an exploded side view of the inner and outer
`cylindrical cams 48 and 50 constituting the bulb-holder
`Separating mechanism 46, and the actuator 28.
`As shown in FIG. 9, a pair of opposed pins 32b are
`provided for the output rod 32 of the actuator 28 and
`correspondingly a pair of cam grooves 48a and 50a are each
`formed in the inner and outer cylindrical cams 48 and 50.
`The cam groove 48a of the inner cylindrical cam 48 is
`Spirally formed relative to a rotational axis X of the output
`rod 32, whereas the cam groove 50a of the outer cylindrical
`cam 50 is formed at the same lead angle as that of the cam
`groove 48a of the inner cylindrical cam 48 and in phase
`there with up to a halfway point. However, the cam groove
`50a of the outer cylindrical cam 50 is so formed as to extend
`circumferentially relative to the rotational axis X from the
`halfway point.
`An inserting hole 48b for receiving the output rod 32 is
`formed in the inner cylindrical cam 48, and a rib 48c for
`Stopping the inner cylindrical cam 48 from rotating is
`formed in its Outer peripheral lower end portion. Moreover,
`a spherical pivot 48d for being coupled to the bracket 20c of
`the reflector 20 is formed in the front end portion of the inner
`cylindrical cam 48.
`An inserting hole 50b for receiving the inner cylindrical
`cam 48 is formed in the outer cylindrical cam 50, and a
`mating groove 50c for being mated with the rib 48c of the
`inner cylindrical cam 48 is formed in the inner peripheral
`lower end portion of the inserting hole 48b. Further, a rib
`50d for stopping the outer cylindrical cam 50 is formed in
`the outer peripheral lower end portion of the outer cylindri
`cal cam 50, and a double annular rib 50e for being mated
`with the L-shaped bracket 40b of the bulb holder 40 is
`formed in the Outer peripheral front end portion. AS further
`shown in FIG. 6, a mating hole 40d for being mated with the
`double annular rib 50e is formed in the L-shaped bracket 40b
`of the bulb holder 40.
`Abeam 52 with a mating groove 52c for being mated with
`the rib 50d of the outer cylindrical cam 50 is provided in the
`front edge face of the actuator body 30 of the actuator 28.
`When the actuator 28 is driven with the inner and outer
`cylindrical cams 48 and 50 fitted to the output rod 32, the
`output rod 32 is rotated but the inner and outer cylindrical
`cams 48 and 50 are not rotated. Consequently, the pins 32b
`of the output rod 32 are moved along the cam grooves 48a
`and 50a, whereby the inner and outer cylindrical cams 48
`and 50 are moved longitudinally. However, the outer cylin
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`15
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`25
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`40
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`6,161,950
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`8
`drical cam 50 is kept Standing Still as it does not receive a
`longitudinal pressing force from the pins 32b when the pins
`32 are positioned in the circumferentially-extended portion
`of the cam groove 50a.
`When the output rod 32 is rotated counterclockwise while
`the pins 32b are positioned in the front end portions of the
`cam grooves 48a and 50a, the inner and outer cylindrical
`cams 48 and 50 are moved forward together relative to the
`output rod 32 up to a halfway point and then only the inner
`cylindrical cam 48 is moved forward from the halfway point.
`An area where the inner and outer cylindrical cams 48 and
`50 are moved forward integrally is an area for use in making
`the leveling adjustment, and an area where only the inner
`cylindrical cam 48 is moved forward is an area for use in
`Switching the low beam to the high beam.
`As set forth above in detail, the high-beam light distri
`bution pattern is not established only by directing the
`low-beam light distribution pattern upward Since the reflec
`tor 20 is tilted separately from the bulb holder 40 midway
`when the reflector 20 is tilted upward according to even this
`embodiment of the invention. To achieve a light distribution
`pattern excellent in remote visibility with a larger portion of
`upward emission light, the leveling actuator 28 can be used
`Simultaneously as a beam Switching actuator. Therefore,
`according to this embodiment of the invention, the leveling
`as well as beam Switching can be carried out with a simple,
`lightweight, inexpensive construction.
`In this embodiment of the invention, moreover, the
`intended function and effect of the invention can be achieved
`with compact construction Since the bulb-holder Separating
`mechanism 46 has been localized close to the output rod 32
`of the leveling actuator 28.
`Although the fulcrum A between the bulb holder 40 and
`the reflector 20 is positioned above the optical axis AX
`according to the aforementioned embodiments of the
`invention, it may be positioned under the optical axis AX.
`Even with the arrangement above, the function and effect of
`the invention can be obtained similarly as in the aforemen
`tioned embodiments of the invention.
`Although the bulb holder 40 and the reflector 20 have
`been described as those which are tilted around the fulcrum
`A Set in the same position according to this embodiment of
`the invention, the tilting fulcrum of the bulb holder 40 may
`be set in a different position from that of the reflector 20. In
`this case, the light distribution pattern may be made different
`from the high-beam light distribution pattern of FIG. 5(b) by
`properly Selecting the position of the tilting fulcrum of the
`bulb holder 40.
`It will be apparent to those skilled in the art that various
`modifications and variations can be made in the manifold
`unit according to the present invention without departing
`from the Spirit or Scope of the invention. Thus, it is intended
`that the present invention cover the modifications and varia
`tions of the invention provided they come within the S