1. Field of the Invention
The invention concerns a clutch which prevents application of excessive force to a mechanism which adjusts headlamps in a vehicle.
2. Description of the Related Art
It is occasionally necessary to adjust the headlamps of a vehicle to assure that their light beams are projected in the correct or desired directions. Mechanisms currently exist for this purpose, and these mechanisms often place limits on the range of adjustment which is possible.
However, when the headlamp arrives at its limit, that arrival may not be apparent to the person making the adjustment. The person may attempt to force the headlamp beyond the limit, thereby causing damage. To prevent this damage, mechanical clutches are often incorporated into the mechanisms to restrict the force which can be applied by the person.
The following U.S. patents and applications, which are hereby incorporated by reference, provide examples of adjustment mechanisms: 2014/0003080 (King); U.S. Pat. No. 7,975,974 (Schaefer); U.S. Pat. No. 5,530,629 (Uehara); U.S. Pat. No. 5,260,857 (Lukkarinen); U.S. Pat. No. 5,267,128 (Shamir); U.S. Pat. No. 5,214,971 (Burton); U.S. Pat. No. 7,264,376 (Burton); U.S. Pat. No. 7,150,541 (Burton); and U.S. Pat. No. 6,974,231 (Burton).
The invention proposes an improved clutch which is simple in design, manufacture and use.
An object of one embodiment of the invention is to provide an improved mechanism for adjusting headlamps.
A further object of one embodiment of the invention is to provide a simple clutch for preventing over-stressing a headlight adjustment mechanism.
In one form of the invention, a worm gear or driven gear is driven by a worm or driving gear mounted on a flexible shaft. The worm gear or driven gear adjusts a position of the headlamp. When the worm gear or driven gear reaches a limit of rotation, the flexible shaft deflects, thereby causing the worm or driving gear to disengage from the worm gear or driven gear, thereby preventing further rotation of the worm gear or driven gear. The deflection acts as a clutch.
In one aspect, one embodiment of the invention comprises an apparatus for aiming a lighting device in a vehicle, comprising a gear which is affixed to a source of light and alters direction of the light when it rotates, and a worm or driving gear which engages the gear and causes the gear to rotate when the worm or driving gear rotates and disengages from the gear and does not cause the gear to rotate when the gear reaches a limit of rotation.
In another aspect, another embodiment of the invention comprises a vehicle lighting device adjuster which adjusts an optical axis of light projected by a light source in a vehicle lighting device comprising a worm gear or driven gear which, when rotated, alters the optical axis of light, and a worm or driving gear which rotates the worm gear or driven gear and holds the worm gear or driven gear in a selected position and acts as a clutch when the worm gear or driven gear reaches a travel limit.
In yet another aspect, another embodiment of the invention comprises a vehicle lighting device adjuster which adjusts optical axis of light projected by a light source comprising a reflector which receives the light and projects the light from a vehicle along the optical axis. an adjustment bracket which supports the reflector, a rotatable worm gear or driven gear which supports the adjustment bracket to thereby rotate the reflector when the worm gear or driven gear rotates, a worm or driving gear which drives the worm gear or driven gear, and a flexible shaft which supports the worm or driving gear and which draws the worm or driving gear out of engagement when loading imposed by the worm gear or driven gear exceeds a predetermined limit.
In still another aspect, another embodiment of the invention comprises a vehicle lighting device comprising an adjuster which adjusts an optical axis of light projected by a light source comprising a reflector which receives the light and projects the light from a vehicle along the optical axis, the adjuster comprising an adjustment housing which supports the reflector, a driven gear which drives the adjustment housing to change a position of the reflector when the driven gear rotates, a driving gear which drives the driven gear, a flexible shaft which supports the driving gear and which draws the driving gear out of engagement when loading imposed by the driven gear exceeds a predetermined limit, and at least one adjustable sealing cap detachably coupled to the adjustment housing and engaging the flexible shaft and allowing it to spin, while providing an adjustment location on the outside of the vehicle lighting device.
This invention, including all embodiments shown and described herein, could be used alone or together and/or in combination with one or more of the features covered by one or more of the claims set forth herein, including but not limited to one or more of the features or steps mentioned in the following bullet list and the claims:
These and other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.
In a preferred embodiment, this invention is used to adjust headlights in motor vehicles.
In
In
However, when the adjustment bracket 16 in
This disengagement provides a clutching function. When the worm or driving gear W becomes disengaged from the worm gear or driven gear WG, as in
Thus, rotation of the control rod 28 in one direction will cause the abutment at abutment point P in
This reengagement can be important when two limits are placed upon the reflector 18. For example,
The second limit SL can be imposed by elements which are mirror images of the reflector 18 and bezel 26 in
The boss 38 of the control rod 28 is captured in the bore 48 (
In one alternate embodiment shown in
1. The rotation of the worm or driving gear W causes rotation of the worm gear or driven gear WG. When the worm gear or driven gear WG strikes its travel limit, such as point P in
Spur gear 66 is the driving gear and spur gear 68 is the driven gear in the example. The gear teeth make contact at point P1. Because of the shapes of the teeth, point P1 is, in effect, residing on an inclined plane or cam surface. The torque applied to the driven spur gear 68 causes forces indicated by arrows A1 and A2, which tends to separate the spur gears 66 and 68.
A worm or driving gear—worm gear or driven gear system can encounter a similar force because the cross-sectional shape of the worm or driving gear W in the region where it contacts the worm gear or driven gear WG is somewhat similar to that of spur gear 66. Of course, this is a simplified explanation, and more detailed explanations are possible.
2. The discussion above considered rotation of the reflector 18 in
3. In another embodiment, the control rod 28 can be flexible and the worm or driving gear W can be rigid. For example, the control rod 28 can be constructed of nylon, and the worm or driving gear W can be constructed of brass. Alternately, the control rod 28 and the worm or driving gear W can be constructed of the same material, such as flexible nylon or plastic. As another alternate and as mentioned earlier, the control rod 28 and the worm or driving gear W can be a single integral component, as would occur if both were injection-molded of nylon in one piece.
4. The preceding discussion assumed that the control rod 28 flexed when the abutment at point P in
Pivoting of the control rod 28 is shown. Instead, the displacement of the worm or driving gear W can occur by allowing the control rod 28 to slide on rails or rods under the bias of spring 70.
5. The gear train comprising worm or driving gear W and worm gear or driven gear WG transfers motion in one direction, namely, from the worm or driving gear W to the worm gear or driven gear WG. Motion is not transferred in the other direction, from the worm gear or driven gear WG to the worm or driving gear W, and this is a standard feature of many worm drives.
Consequently, the worm or driving gear W serves to hold the worm gear or driven gear WG in a fixed position once rotation of the worm or driving gear W drives the worm gear or driven gear WG into that position.
When the disengagement of
6. From one perspective, the gear train identified and discussed relative to
7. The clutching rod adjuster disclosed can be used with embodiments such as those disclosed in U.S. Patent Application. 2014/0003080 (King) filed Jun. 29, 2012, or one of the present inventor's co-pending applications, such as U.S. Ser. No. 13/558,720, filed Jul. 26, 2012, entitled “Multiple Lamp Element Adjuster for a Vehicle.” These are both hereby incorporated herein by reference and made a part hereof.
8. In one form of the invention, the disengagement of the worm or driving gear W occurs at a specific torque value in order not to damage the head lamp adjustment device when it is in a bind or at a mechanical limit. This torque value is frequently requested in specifications issued by car makers to lamp set makers and the device is engineered to meet these limits. The “clutching rod headlamp adjuster” utilizes a rod 28 that is typically made from a plastic, such as a grade of nylon, that had a defined bending tolerance when engaging an adjuster system. When the headlamp adjustment exceeds the specified torque, the amount of bend or deflection in the rod 28 will be that required to “clutch’ and not further adjust the lamp.
9. The control rod 28 does not require a circular cross-section, e.g., it could have a square or polygonal cross section, but for convenience can he referred to as a rod. It is contemplated that the control rod 28 has any convenient cross-sectional shape and supported length that is suitable. The control rod 28 has a designed pitched thread incorporated in the shaft and the adjusting device will have the matching gear-styled threads that perform the adjustment. The matching threads can be provided on the rotating adjuster as shown in the figures or be incorporated on the reflector 18 to further reduce part count.
10. The depicted clutching rod headlamp adjuster includes three components: clutching adjustment rod 28, adjusting gear WG and at least one sealed adjusting cap 36. These can be made of a low cost plastics material. The clutching adjustment rod 28 is rotatably disposed in a headlamp housing, trapped in a designed channel that holds the rod so it can rotate. The upper and lower pivotal support regions will be set at a specific distance between two imaginary points along the longitudinal axis of the control rod 28, this distance being indicated as D in
The distance between the trapped end and the adjusting gear and the amount of thread engagement will be used to calculate the amount of the flex the adjusting control rod 28 tends to undergo in order to give the proper clutching torque value required to meet a specification. The flex will be considered when choosing the material of which to make the control rod 28. The flex of the control rod 28 is a result of the materials modulus of elasticity and the moment of inertia of the cross-sectional shape of the control rod 28.
11. The headlamp housing is designed with two attachment points for pivotal bearings at a calculated value for the mounting of the clutching rod headlamp adjuster. The geared adjusting pivot mating cooperates with the clutching adjustment rod thread pitch at a designed distance from the fixed end of the adjusting rod. The geared adjusting pivot is mounted to or in relationship to the housing so that it can be attaching to the movable optical elements. The clutching adjustment rod contains a thread that matches the pivotally mounted rotating adjustment gear. The clutching adjustment rod 28 rotates so as to adjust the optical elements, e.g., the reflector 18 or light source itself. The clutching adjustment rod 28 is made of a material that consistently provides a nominal flex when in an over-torque situation. The geared adjusting pivot can be designed to align one or more than one optical element during rotation of the clutching adjustment rod.
12. The at least one sealed adjusting cap 36 illustrated in the figures simplifies assembly and reduces or eliminates the need for a right-angle adjusting gear and this is expected to reduce cost of the assembly. The use of the at least one sealed adjusting cap 36 facilitates adjusting multiple optical elements simultaneously. The at least one sealed adjusting cap 36 snaps into the top of the headlamp housing providing an engagement to the adjusting rod 28 that allows it to spin, while providing an adjustment location on the outside of the headlamp that is serviceable by the car-maker during assembly of the headlamp and also by the ultimate end consumer vehicle operator for maintenance. Headlamps that lack an internal moveable optical system would not require the at least one sealed adjusting cap 36.
This invention, including all embodiments shown and described herein, could be used alone or together and/or in combination with one or more of the features covered by one or more of the claims set forth herein, including but not limited to one or more of the features or steps mentioned in the Summary of the Invention and the claims.
While the system, apparatus, process and method herein described constitute preferred embodiments of this invention, it is to be understood that the invention is not limited to this precise system, apparatus, process and method, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.
The present application claims priority to provisional U.S. Application Ser. No. 61/928,018 filed Jan. 16, 2014, to which Applicant claims the benefit of the earlier filing date. The provisional application is incorporated herein by reference and made a part hereof.
Number | Date | Country | |
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61928018 | Jan 2014 | US |