Abstract:
A headlamp adjuster for adjusting the position of a reflector includes a base housing with a slide positioned at least partially therein. The base housing has mounting tabs so that the adjuster can be secured to the back of a headlamp assembly support frame. The base housing also has channels along its sides in which rails extending from the slide are disposed. A ball stud extends from the slide, the ball of which engages the reflector within the headlamp assembly such that axial movement of the ball stud causes movement of the reflector. Movement of the slide is caused by rotation of an adjustment screw that is threaded into the slide but held in axial position with respect to the base housing. The adjuster may include a vehicle headlamp aiming device (“VHAD”) if required for the particular application.” A marked-up version showing the changes is enclosed herewith in accordance with 37 CFR §1.121 (b)(iii).

Description:
This application is a continuation of U.S. patent application Ser. No. 09/504,250 filed Feb. 15, 2000 now U.S. Pat. No. 6,474,850. 

   FIELD OF THE INVENTION 
   This invention relates generally to adjuster mechanisms, and more particularly to a sliding headlamp adjuster mechanism for use in motor vehicles. 
   BACKGROUND OF THE INVENTION 
   In traditional sealed beam style headlamps; the lamp&#39;s aim is adjusted by rotating one or more screws that hold the frame of the lamp to the vehicle. Such adjustment is made from the front of the vehicle by inserting a screwdriver or the like between the lamp frame and the vehicle trim and turning the screws to alter the orientation of the lamp and effectuate the desired adjustment. As the design of motor vehicles has evolved, headlamps have continually been reconfigured to improve the aerodynamics and styling of the front end of the vehicle. Modern headlamps are designed so that their lenses follow the contour of the vehicle to provide an aerodynamically efficient exterior surface. Adjustment of these headlamps must still be performed in order to provide an optimal beam of light and to prevent the aiming of light beams toward oncoming vehicles. Such adjustment is made by moving a reflector within the lamp assembly so that light is directed in the desired manner. Automotive manufacturers+ demand for aerodynamically efficient headlamp designs has lead to modular designs where the headlamp adjustment mechanism is located within the interior of the engine compartment and positioned such that adjustment can easily performed without removing any trim pieces. Thus, the constraints of the installation area and the demands of the automobile manufacturers for aerodynamic headlamp designs dictate the location from which adjustment must be made. 
   There are many adjuster devices designed for use in connection with aerodynamic headlight designs including, among others, the devices disclosed in U.S. Pat. Nos. 5,707,133 and 5,214,971 to Burton, the inventor of the present invention. Modern automotive headlamp assemblies typically include several basic parts: a support frame, a reflector, a lens, a bulb, and one or more adjusters. The support frame houses the reflector and the bulb on a pivotable mounting to allow the aim of the light to be adjusted using the adjuster and provides a mounting surface for attaching adjusters. The lens seals the front of the support frame to protect it from the elements assailing the front end of the vehicle and provides an aerodynamic shape and attractive appearance. The reflector mounts on one fixed ball joint and is adjustable horizontally and vertically using adjusters that interface with the reflector through moving ball joints. The moving ball joints are moved by actuating the adjusters connected to the moving ball joints by a ball stud. Geared angle style adjusters, such as the ones disclosed in the referenced Burton patents, are often used to adjust the aim of the headlamp. However, such devices are designed to allow adjustment of the headlamp from a location behind the assembly, typically from within the engine compartment and immediately behind and above the lamp assembly. Accordingly, such devices cannot be effectively used in vehicles where the area immediately behind and above the lamp assembly is not accessible. One such vehicle design is shown in FIG.  14 . In that design, the vehicle fender  20  covers the headlamp assembly  22  rendering the area behind and above the assembly substantially inaccessible without removal of the fender  20  of the vehicle. The area below the headlamp assembly  22  is similarly inaccessible because of the bumper  21  and other vehicle components. Thus, existing geared angle style headlamp adjusters have not been found to be effective for use in such vehicle designs. 
   Conventionally in a vehicle such as the one shown in  FIG. 14 , a sealed beam style headlamp is used. However, due to consumer and vehicle manufacturer styling preferences and performance objectives, it is desirable to use a reflector style headlamp in such vehicles. The conventional method for adjusting sealed beam lamps cannot be used to adjust a reflector style lamp and the area immediately above and behind the lamp is inaccessible such that a conventional geared angle style adjuster cannot be used. Accordingly, a need exists for a headlamp adjuster which can be used in connection with a vehicle design where the area behind and above the lamp assembly is substantially inaccessible and the use of a reflector style lamp is desired. 
   SUMMARY OF THE INVENTION 
   The present invention relates to a sliding headlamp adjuster that allows for precise adjustment control, can be used where the area above and behind the lamp assembly is inaccessible, ensures smooth operation, can include a vehicle headlamp aiming device (“VHAD”), is cost effective, and which solves the problems raised or not solved by existing headlamp adjuster designs. As described in more detail below and shown in the accompanying drawings, the sliding headlamp adjuster uses a two-piece sliding body construction to meet these objectives. 
   A headlamp adjuster in accordance with one embodiment of the present invention includes a base housing with a slide disposed at least partially therein. The base housing includes one or more mounting tabs such that the adjuster can be mounted to the back of a headlamp assembly support frame. The base housing has channels along its sides in which rails extending from the slide are disposed. A ball stud is threaded into the slide and protrudes therefrom passing through the base housing into the headlamp assembly. The ball of the ball stud is engaged in a socket in the reflector so that axial movement of the ball stud causes movement of the reflector. The ball stud is caused to axially move by a corresponding sliding of the slide along the channels in the base. Movement of the slide results from rotation of an adjustment screw that is threaded into the sliding piece but held in axial position (free to rotate) in the base. Thus, rotation of the axially-fixed adjustment screw causes movement of the slide and the ball stud with respect to the base housing. Because the base is fixed to the headlamp assembly support frame and the ball is engaged in a socket in the reflector, rotation of the adjusting screw causes changes in the orientation of the reflector within the assembly and the aim of the lamp is thereby adjusted. 
   In certain applications, the adjuster must include a VHAD. U.S. National Highway Traffic Safety Administration (“NHTSA”) standards require that horizontal adjuster mechanisms be either non-readjustable after the proper aim has been achieved or be equipped with a non-recalibratable VHAD. Currently, VHADs are required for horizontal adjusters but not for vertical adjusters. The VHAD used in the sliding adjuster includes an indicator plate with a post extending therefrom. The post includes a groove with a partial helical twist and is axially fixed (free to rotate) with respect to the base housing. A tab jutting from the slide is disposed in the groove. The indicator plate is positioned on the base near the adjustment screw such that indicator lines on the plate can be seen by the person adjusting the aim of the lamp. The base includes aiming rails behind the plate that, in connection with the indicator lines, allow the person making the adjustment to perceive how much of an adjustment has been made. Because the groove includes a partial helical twist, as the tab jutting from the slide moves along the groove with movement of the slide, the post and indicator plate are caused to rotate. The scale of the movement of the plate as reflected in the indicator lines is designed to reflect the corresponding movement of the reflector. If no VHAD is required, the indicator plate and post are simply not installed in the sliding adjuster. 
   The new design has numerous benefits that make it advantageous for use in connection with reflector style headlamps. The new design allows precise control of reflector aim, has smooth operational characteristics, can include a VHAD, and effectively maintains adjustment. Further, the new adjuster can be used where the area above and behind the lamp is inaccessible and it is cost effective to manufacture and install. 
   While the present invention is particularly useful in automotive headlamp assemblies, other applications are certainly possible and references herein to use in a headlamp assembly should not be deemed to limit the application of the present invention. Rather, the present invention may be advantageously adapted for use where similar performance capabilities and characteristics are desired. These and other objects and advantages of the present invention will become apparent from the detailed description, claims, and accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a sliding headlamp adjuster constructed in accordance with one embodiment of the present invention; 
       FIG. 2  is a front view of a sliding headlamp adjuster constructed in accordance with one embodiment of the present invention; 
       FIG. 3  is a rear view of a sliding headlamp adjuster constructed in accordance with one embodiment of the present invention; 
       FIG. 4  is a section detail of the rear view of a sliding headlamp adjuster constructed in accordance with the embodiment of the present invention shown in  FIG. 3 ; 
       FIG. 5   a  is cross-sectional view of the adjustment screw shown in  FIG. 6  taken generally along the line  5   a — 5   a;    
       FIG. 5   b  is a perspective view of a portion of the adjustment screw shown in  FIG. 6 ; 
       FIG. 5   c  is a section detail of the threads of the adjustment screw shown in  FIG. 5   b;    
       FIG. 6  is a partial cross-section of the sliding headlamp adjuster in  FIG. 3  taken generally along the line  6 — 6 ; 
       FIG. 7  is a partial front view of a sliding headlamp adjuster in accordance with one embodiment of the present invention wherein the adjustment screw is being rotated in the direction of arrow  92  resulting in movement of the VHAD indicator plate in the direction of arrow  96 ; 
       FIG. 8  is a perspective view of a sliding headlamp adjuster in accordance with one embodiment of the present invention with the adjustment screw being rotated in the direction of arrow  92  resulting on movement of the VHAD indicator plate in the direction of arrow  96  and the ball stud in the direction of arrow  94 ; 
       FIG. 9  is another rending of the cross-section shown in  FIG. 6  with the adjustment screw having been rotated such that the slide is in a different position from that shown in  FIG. 6 ; 
       FIG. 10  is partial front view of a sliding headlamp adjuster in accordance with one embodiment of the present invention wherein the adjustment screw is being rotated in the direction of arrow  98  resulting in movement of the VHAD indicator plate in the direction of arrow  100 ; 
       FIG. 11  is a side view of a sliding headlamp adjuster in accordance with one embodiment of the present invention installed in a headlamp assembly; 
       FIG. 12  is a schematic representation of the positioning of sliding headlamp adjusters in accordance with the present invention with respect to a headlamp assembly; 
       FIG. 13  is a front view of a sliding headlamp adjuster in accordance with one embodiment of the present invention shown in an installed position; and 
       FIG. 14  is a perspective view of a vehicle with which a sliding headlamp adjuster in accordance with the present invention might advantageously be used. 
   

   DETAILED DESCRIPTION 
   As shown in  FIGS. 1 and 2 , a sliding headlamp adjuster (identified generally as  24 ) in accordance with one embodiment of the present invention includes a base housing  26  with a slide  28  disposed at least partially therein. The base housing  28  has one or more mounting tabs  30  such that the adjuster  24  can be mounted to the back of a headlamp assembly support frame  32  (see FIG.  11 ). The amount and configuration of the tabs  30  can be configured as necessary for particular installations. Alternatively, a quarter-turn mounting system could be used. The base housing  26  has interior channels  34  running along its sides  36 . When viewed from the exterior, e.g.,  FIG. 1 , the channels  34  appear rectangular in cross-section. However, as shown in FIG.  3  and in detail in  FIG. 4 , on the interior, the channels  34  have a generally sideways T-shaped open cross section with a top T portion  38 , a bottom T portion  40  and a narrower neck T portion  42 . 
   As shown in  FIGS. 3 and 4 , the slide  28  has rails extending from each of its sides. The rails include an upper rail  44  and a lower rail  46 . Each rail includes a leg  48  with a foot  50  extending therefrom. The rails  44  and  46  are disposed within the channels  34  so as to allow the slide  28  to move with respect to the base housing  26 . As shown in  FIG. 8 , rails  44  and  46  extend along the side(s) of the slide and provide ample length of engagement to allow a smooth sliding movement and to resist binding. As shown in  FIG. 4 , the leg  48  of the lower rail  46  interfaces with the neck portion  42  of the channel  34 . Because this interface is relatively near to the base of the leg  48 , there is little flex of the leg  48 . The foot  50  of upper rail  44  interfaces with the top T portion  38  of the channel  34  such that the leg  48  is flexed at an angle as indicated by arrows  52  which reflect the difference from straight of the leg  48 . The continually flexed engagement of the upper rail  44  with the channel  34  helps reduce any “play” or “slop” in the operation of the adjuster  24 , reduces problematic headlamp “flutter” (flutter is the apparent flickering of a headlamp caused by an improperly secured headlamp that moves when a vehicle hits a bump), and maintains the adjuster  24  in the desired adjustment. This resistance to “flutter” is typically tested by applying a set force to the ball stud  52  in the opposite direction of arrow  94  as shown in  FIG. 8  while measuring the resulting deflection of the ball stud  52  in the same direction. In this test, deflection of the ball stud  52  is resisted primarily by the rigidity of the slide  28 , the slide rail  44  and housing channel  34  connection described, and the connection points of adjustment screw  58 . The rail and channel connection is subjected to a bending moment when the test load is applied urging the slide to rock in the rail channel. Minimizing rocking of the slide in the rail channel area as result of this bending moment minimizes deflection of the ball stud  52 . Since the leg  48  in the lower rail  46  resists flex, a greater resistance to rocking and hence to deflection is achieved. While this configuration for the engagement between the rails  44  and  46  and the channels  34  has been found effective, alternative configurations could also be effective. Similarly, while it has been found effective to have two rail/channel engagements, one on each side of the base housing  26  and slide  28 , other numbers and configurations could be used. For example, if additional stability is desired, an additional rail/channel could be provided. 
   As shown in  FIG. 11 , a ball stud  52  extends from the slide  28  passing through the base housing  26  and the assembly support frame  32  and into the headlamp assembly  22 . The ball  54  of the ball stud  52  is engaged in a socket (not shown) in the reflector  56  so that axial movement of the ball stud  52  causes movement of the reflector  56 . The ball stud  52  is caused to move along its axis by movement of the slide  28  along the channels  34  in the base housing  26 . Movement of the slide  28  results from rotation of an adjustment screw  58  that is threaded into the slide  28 . 
   As shown in  FIG. 5   b , the adjustment screw  58  has a head  62 , a narrow neck portion  64 , and a threaded portion  68 . The adjustment screw  58  is free to rotate and is secured in axial position in the base housing  26  by a screw retainer clip  60  ( FIGS. 1 and 2 ) that snap-fits around the narrow neck portion  64  of the adjustment screw  58 . Because the adjustment screw  58  is threaded into the slide  28  but is axially fixed and free to rotate with respect to the base housing  26 , when the adjustment screw  58  is rotated it causes movement of the slide  28  with respect to the base housing  26 . Thus, rotation of the adjustment screw  58  causes movement of the ball stud  52  with respect to the base housing  26 . Because the base housing  26  is fixed to the headlamp assembly support frame  32  and the ball  54  is engaged in a socket in the reflector  56 , rotation of the adjusting screw  58  causes changes in the orientation of the reflector  56  within the assembly  22  and the aim of the lamp is thereby adjusted. 
   As shown in  FIGS. 5   a  and  5   b , the adjustment screw  58  may include an anti-thread-stripping plate  66  between the narrow neck portion  64  and the threaded portion  68 . The anti-thread-stripping plate  66  is a disc-shaped protrusion from the shaft of the adjustment screw  58  that has one or more engagement barbs  70 . The purpose of the anti-thread-stripping plate is to reduce the possibility of the threaded portion  66  of the adjustment screw stripping the plastic threads in the slide  28  when an over-adjustment is attempted. As best visualized by referring to  FIG. 9 , if the adjustment screw  58  is rotated to the point where the slide  28  abuts the anti-thread-stripping plate  66 , the engagement barbs  70  project into the end of the slide  28  to prevent further rotation of the adjustment screw  58 . Thus, stripping of the threads in the slide  28  in which the adjustment screw  58  is engaged is prevented because the adjustment screw  58  cannot be further rotated. The adjustment screw  58  can be rotated to release the engagement barbs  70  to restore the normal operation of the adjuster  24 . 
   Preferably, the base housing  26  and slide  28  are manufactured from glass-filled nylon using conventional injection molding processes. The ball stud  52  is preferably made from steel and manufactured in a conventional cold-heading process. Due to the possible exposure to harsh elements, manufacturing the adjustment screw  58  from a zinc alloy using a die casting method is preferably to help prevent corrosion and increase durability. As shown in  FIGS. 5   b  and  5   c , the threaded portion  68  of the adjustment screw  58  has flattened sides  72  and a forty-five degree thread angle. The flattened sides  72 , while facilitating manufacture of the adjustment screw  58  using a die-cast process, are advantageous in that they facilitate a thread-forming initial threading of the adjustment screw  58  into the slide  28 . Similarly, the forty-five degree thread angle is advantageous in the thread forming because it requires the displacement of a minimal amount of material while maximizing the strength of the threads in the slide  28 . The combined use of a forty-five degree thread angle and flattened sides  72  is helpful in achieving a low drive torque, low prevailing torque, and a resistance to stripping. Of course, other materials and part configurations could be used for particular designs and the description herein of particular materials and configurations should not be deemed to limit the scope of the invention. For example, the ball stud  52  could be manufactured from plastic or a metal other than steel and other plastics or materials could be used to form the base housing  26  and slide  28 . 
   In certain applications, the adjuster  24  must include a VHAD. Preferably, the VHAD used in the sliding adjuster (identified generally as  74 ) includes an indicator plate  76  with a post  78  extending therefrom. The post  78  includes a groove  80  with a partial helical twist  62  ( FIGS. 6 and 9 ) and is axially fixed (free to rotate) in a snap fit to the base housing  26 . A tab  84  jutting from the slide  28  is disposed in the groove  80 . The indicator plate  76  is positioned on the base  26  near the adjustment screw  58  such that indicator lines  86  on the plate  76  can be seen by the person adjusting the aim of the lamp. The base housing  26  includes aiming rails  88  behind the plate  76  that, in connection with the indicator lines  86 , allow the person making the adjustment to perceive how much of an adjustment has been made. Because the groove  80  includes a partial helical twist  62 , as the tab  84  jutting from the slide  28  moves along the groove  80  with movement of the slide  28 , the post  78  and indicator plate  76  are caused to rotate. The scale of the movement of the indicator plate  76  with respect to the aiming rails  88  is designed to reflect the corresponding movement of the reflector  56  within the assembly  22 . If no VHAD is required, the VHAD  74  is simply not installed in the sliding adjuster  24 . While other materials could be used, manufacture of the VHAD  74  from nylon using an injection molding process is preferable. 
   As shown in  FIGS. 11 ,  12  and  13 , the sliding headlamp adjuster  24  is installed to the rear of the headlamp assembly  22  using the mounting tabs  30 . The ball stud  52  extends into the assembly  22  through the support frame  32  where the ball  54  is disposed in a socket in the reflector  56 . An o-ring  57  may be disposed about the ball stud  52  to provide a seal between the shaft of the ball stud  52  and the assembly support frame  32 . A lens  90  covers the front of the support frame  32  and protects the reflector  56  and bulb (not shown) from the elements assailing the front of the vehicle. In  FIG. 12 , the left adjuster  24  controls the horizontal movement of the reflector  56  and is thus equipped with a VHAD  74 . The right adjuster  24  controls the vertical movement of the reflector  56  and is not equipped with a VHAD. As shown in detail in  FIG. 13 , the adjustment screw  58  and VHAD indicator plate  76  are positioned such that they are visible and accessible from the front of the vehicle between the lens  90  and the bumper  21 . The indicator plate  76  includes indicator lines  86  that are appropriate for reflecting adjustment when the adjuster is installed on either side of a vehicle. A portion of the indicator plate  76  is covered by the assembly support frame  32  or lens  90  such that the indicator lines  86  that are visible through the gap will properly reflect the adjustment being made. Such a covering of the indicator plate  76  allows the manufacturer to supply one adjuster for installation on both sides of the vehicle. Alternatively, the indicator plate  76  could have indicator lines that are specifically arranged for a particular side of the vehicle. 
   The operation of the sliding headlamp adjuster  24  to effectuate adjustment of the reflector  56  once installed is quite simple. As shown in FIG.  8  and in detail in  FIG. 7 , rotation of the adjustment screw  58  in the direction indicated by arrow  92  causes the slide  28  to move toward the head  62  of the adjustment screw  58 . This movement of the slide  28  results in the movement of the ball stud  52  in the direction indicated by arrow  94 . As the tab  84  that extends from the slide  28  into the groove  80  moves with the slide  28 , the tab  84  is caused to move within the groove  80  and along the partial helical twist  82 . Movement of the tab  84  along the partial helical twist  82  causes a rotation of the post  78  and indicator plate  76  of the VHAD  74  in the direction indicated by arrow  96 . The amount that that the ball stud  52  has moved (and caused adjustment of the reflector  56 ) is shown by reference to the indicator lines  86  and aiming rails  88 . 
   Operation of the adjuster  24  to effectuate movement of the ball stud  52  in the opposite direction of that described in the immediately preceding paragraph is shown in FIG.  10 . In such operation, the adjustment screw  58  is rotated in the direction indicated by arrow  98  which causes the slide  28  to move away from the head  62  of the adjustment screw  58 . This movement of the slide  28  results in the movement of the ball stud  52  in the direction opposite that indicated by arrow  94  in FIG.  8 . As the tab  84  that extends from the slide  28  into the groove  80  moves with the slide  28 , the tab  84  is caused to move within the groove  80  and along the partial helical twist  82 . Movement of the tab  84  along the partial helical twist  82  causes a rotation of the post  78  and indicator plate  76  of the VHAD  74  in the direction indicated by arrow  100 . The amount that the ball stud  52  has moved (and caused adjustment of the reflector  56 ) is shown by reference to the indicator lines  86  and aiming rails  88 . 
   As illustrated by the foregoing description and shown in the Figures, the present invention is more suitable as a headlamp adjuster than are conventional adjusters. The present invention overcomes the limitations and disadvantages of existing adjusters by utilizing an effective design which allows precise control of reflector aim, has smooth operational characteristics, effectively maintains adjustment, can be used where the area behind and above the lamp is inaccessible, and which is cost effective and efficient to manufacture and install. 
   Although the invention has been herein shown and described in what is perceived to be the most practical and preferred embodiments, it is to be understood that the invention is not intended to be limited to the specific embodiments set forth above. Rather, it is recognized that modifications may be made by one of skill in the art of the invention without departing from the spirit or intent of the invention and therefore, the invention is to be taken as including all reasonable equivalents to the subject matter of the appended claims.