Patent Description:
Vehicles such as automobiles typically have several lamps that can be fixed in a housing supporting a reflector and a lens which are often securely fit into mounting brackets attached to the vehicle. Together, a lamp (or lamps) and a mounting bracket form a complete lamp assembly. Once the lamp assembly has been manufactured and installed into a vehicle, the lamp must be adjusted to the proper aim. Typically, the adjustment is in both the vertical and horizontal directions although, depending on the type of lamp and applicable regulations, adjustment in only one direction may be required.

One method of adjusting the aim of the lamp involves using an adjuster. The adjuster can be formed as part of the mounting bracket, part of the housing, or can be a separate part between the housing and the mounting bracket (or the reflector directly if no separate mounting bracket is used). One known type of adjuster includes a housing and a ball stud extending therefrom. The ball stud is engaged to the reflector directly or to a mounting bracket on which the reflector is positioned. Actuation or operation of the adjuster causes the ball stud to move. Such movement causes the mounting bracket and/or reflector to pivot or otherwise move with respect to the housing, thereby adjusting the aim of the lamp. One example of this type of adjuster is disclosed in <CIT>. The housing of the adjuster in this Burton design has an opening and a gear positioned inside the housing. The gear is functionally engaged to a ball stud. An input shaft is positioned in the opening and interacts with the gear. Actuation of the input shaft results in rotation of the gear and engaged ball stud. The gear translates actuation of the input shaft into axial movement of the ball stud and its ball stud end. Numerous variations exist on this general concept.

Various automotive headlight and headlight assembly designs use LED and/or high intensity discharge (HID) light sources for primary illumination. The importance of proper aiming of these very bright vehicle headlights to avoid glare that can blind oncoming drivers is known. As optimal nighttime visibility with minimal impact of glare is the main purpose for headlights, the proper aiming of headlights will be of increased importance to the automotive market. Generally, headlight aiming is performed by the manufacturer of the vehicle during assembly using desired criteria. Typical headlamp adjusters have low gear ratios that provide a faster, albeit coarse, adjustment. These adjusters allow for quick adjustment during assembly, but unfortunately these coarse adjustments do not allow for a high degree of fine adjustment, as one might desire with a precise and bright light source, such as provided by LEDs.

Although various right angle headlamp adjusters are known, such as disclosed in <CIT>; <CIT>; and <CIT>, as well as <CIT>, <CIT>, and <CIT>, these mechanisms only provide a coarse adjustment resulting in a relatively large linear movement of an associated ball stud component.

<CIT> discloses a radially shiftable gear for a speed-changing mechanism, wherein a transfer gear on one of two coaxial main shafts providing the output and input of a variable-speed-ratio transmission is in permanent mesh with a plurality of coacting gears on respective ancillary shafts paralleling the main shafts.

<CIT> discloses a gear drive comprising a pair of inter-meshing gears having teeth inclined to the direction of their respective axes, at least one of said gears having teeth of changing axial lead so as to receive different axial thrust components per unit of torque transmitted at different points lengthwise of a tooth.

<CIT> discloses a shuttle stop force limiter, in which a shuttle is movable axially relative to a rotary input member by continued rotation of the rotary input member so that a stop on the shuttle moves from an ambush position allowing free rotation of the rotary input member to a blocking position preventing further rotation of the rotary input member.

<CIT> discloses a mechanism for the conversion of a linear motion of a first element to a rotary motion of a second element, using a flexible pulling element such as a chain or cord as the first element and a shaft to be adjusted as the second element, said pulling element mating with the outer periphery of a roller connected to the shaft to be adjusted.

<CIT> discloses a transmission device including an external transmission device, an internal transmission device, and a spacer ring. The external transmission device is cylindrical and has an outer wall and an inner wall. The inner wall has a plurality of inwardly extending arc-shaped protrusions. The internal transmission device is disposed in the inner wall and has an outer circumferential surface including a plurality of outwardly extending arc-shaped protrusions. The spacer ring is located between and contacts the arc-shaped protrusions of the external transmission device and the arc-shaped protrusions of the internal transmission device.

The aforementioned drawbacks of the prior art are overcome by the present invention. According to the invention there is provided a fine pitch adjuster that includes: a housing; a wheel gear positioned within the housing and coupled to a ball stud, wherein rotation of the wheel gear provides inward and outward longitudinal translation of the ball stud relative to the housing; and a clutching worm input drive including: an inner drive sleeve having a shaft portion and a head portion, the shaft portion including a plurality of sleeve slots formed therein and a plurality of engagement ribs extending longitudinally and radially therefrom; and an outer worm gear sleeve rotationally mounted at least partially in the housing and having worm gear threads extending radially therefrom, the worm gear threads coupled at least indirectly to the wheel gear, and an inner chamber for receiving the shaft portion therein, the outer worm gear sleeve including a plurality of grooves extending longitudinally along the inner chamber for mating engagement with the plurality of engagement ribs, wherein rotation of the inner drive sleeve provides clutchable engagement with the outer worm gear sleeve to rotate the wheel gear, wherein clutching of the clutchable engagement includes the plurality of engagement ribs moving radially inward by a partial collapse of the shaft portion of the inner drive sleeve.

Furthermore according to the invention there is provided a clutching worm input drive for a fine pitch adjuster that includes: an inner drive sleeve having a shaft portion and a head portion, the shaft portion including a plurality of sleeve slots formed therein and a plurality of engagement ribs extending longitudinally and radially therefrom; and an outer worm gear sleeve having worm gear threads extending radially therefrom and couplable at least indirectly to a wheel gear of the fine pitch adjuster, and an inner chamber for receiving the shaft portion therein, the outer worm gear sleeve including a plurality of grooves extending longitudinally along the inner chamber for mating engagement with the engagement ribs, wherein the inner drive sleeve is in clutchable engagement with the outer worm gear sleeve, wherein the plurality of engagement ribs are movable radially inward by a partial collapse of the shaft portion of the inner drive sleeve to provide clutching between the inner drive sleeve and the outer worm gear sleeve. Embodiments of the invention are laid down in the dependent claims.

Embodiments aspects, and features of the invention will be understood and appreciated upon a full reading of the detailed description and the claims that follow.

Embodiments of the invention are disclosed with reference to the accompanying drawings and are for illustrative purposes only. In the drawings:.

Referring to <FIG>, an exemplary fine pitch adjuster <NUM> is shown in front and rear perspective views. The fine pitch adjuster <NUM> is used in vehicle applications to allow for fine aiming adjustments of vehicle lamps and lamp assemblies. The fine pitch adjuster <NUM> includes a housing <NUM>, which in at least some embodiments, can be a multipart housing including a front portion <NUM> securable to a rear portion <NUM>, with the front portion <NUM> including a nose <NUM>. Further referring to <FIG> and <FIG> providing exploded front and rear perspective views of the fine pitch adjuster <NUM>, the housing <NUM> a least partially encloses a ball stud <NUM> coupled with a helical ball stud wheel gear <NUM>. The ball stud <NUM> includes a ball head <NUM> and threaded section <NUM>, in at least some embodiments, the threaded section further including a pair of longitudinal guide slots <NUM> on opposite sides of the threaded section <NUM>.

The ball stud wheel gear <NUM> includes a cylindrical body <NUM> with beveled ball stud gear teeth <NUM> extending radially therearound a portion thereof and a pair of internal guide ribs <NUM> (see <FIG>). One or more O-rings <NUM> can be provided around the body <NUM> to provide sealing. The threaded section <NUM> of the ball stud <NUM> is threadingly engaged with threads <NUM> in the nose <NUM>, and the guide slots <NUM> are slidingly engaged with the guide ribs <NUM>. When the ball stud wheel gear <NUM> is rotated withing the housing <NUM> the ball stud <NUM> is also rotated via the engagement of the guide slots <NUM> with the guide ribs <NUM> and translates into or out of the nose <NUM> via the threaded engagement causing the ball head <NUM> to be less or more linearly displaced from the housing <NUM>, this displacement results in movement of the coupled vehicle lamps or lamp assemblies to provide an alignment adjustment.

Referring generally to <FIG>, as well as <FIG>, an exemplary worm input drive <NUM> is shown, which in at least some embodiments, is rotationally mounted at least partially in the housing <NUM>. In at least some embodiments, the worm input drive <NUM> includes an inner drive sleeve <NUM> having a shaft portion <NUM> and a head portion <NUM>, the shaft portion <NUM> including a plurality of sleeve slots <NUM> formed therein and a plurality of engagement ribs <NUM> extending radially therefrom and longitudinally along the shaft portion <NUM>. The worm input drive <NUM> further including an outer worm gear sleeve <NUM> having an inner chamber <NUM> for receiving the shaft portion <NUM> of the inner drive sleeve <NUM> therein. The outer worm gear sleeve <NUM> also includes a plurality of engagement grooves <NUM> extending longitudinally along the inner chamber <NUM> for mating engagement with the engagement ribs <NUM>. The outer worm gear sleeve <NUM> further includes worm gear threads <NUM> extending radially therefrom. The worm gear threads <NUM> are sized and shaped to matingly engage with the ball stud gear teeth <NUM> such that rotation of the outer worm gear sleeve <NUM> around a worm input drive central longitudinal axis <NUM> causes rotation of the ball stud wheel gear <NUM> and effectively longitudinal translation of the ball stud <NUM>. The size and pitch of the worm gear threads <NUM> can be selected to provide the desired level of rotation to the ball stud wheel gear <NUM> and resultant translation of the ball stud <NUM>. The worm gear threads <NUM> can be configured to engage any of numerous gear configurations found in various types of adjuster configurations. In at least some embodiments, the outer worm gear sleeve <NUM> further includes a top flange portion <NUM> and a bottom flange portion <NUM>, wherein the top flange portion <NUM> and the bottom flange portion <NUM> are situated outside of the housing <NUM> to rotatably secure the outer worm gear sleeve <NUM> in position. In at least some embodiments, the top flange portion <NUM> and/or bottom flange portion <NUM> is cylindrical having a flat bottom.

The head portion <NUM> of the inner drive sleeve <NUM> can include a tool engaging portion <NUM>, such as a hex depression or protrusion, configured to engage a tool, such as a hex driver, for selectively rotating the inner drive sleeve <NUM>. Rotation of the inner drive sleeve <NUM> causes the outer worm gear sleeve <NUM> to rotate due to the engagement of the engagement ribs <NUM> with the engagement grooves <NUM>. As such, due to the various aforementioned engagements, rotation of the head portion <NUM> in a first direction causes the ball stud <NUM> to translate longitudinally (linearly) into the nose <NUM>, and rotation of the head portion <NUM> in a second direction causes the ball stud <NUM> to translate longitudinally out of the nose <NUM>.

The use of worm gear threads <NUM>, as opposed to a bevel gear (which would need to be prohibitively large), allows for a notable reduction in ball stud wheel gear <NUM> rotation relative to the rotation of the head portion <NUM> (high gear ratio), while allowing the adjuster <NUM> to maintain a compact size. For example, in at least some embodiments, a <NUM>-degree rotation of the head portion <NUM> provides a ball stud linear translation of about <NUM> millimeters relative to the housing <NUM>, while in other embodiments, more or less translation can be provided. In addition, as the worm gear threads <NUM> of the worm input drive <NUM> tend to provide a self-locking engagement with the beveled ball stud gear teeth <NUM>, the aiming adjustment can be maintained even when subject to vibrations, without requiring a prohibitively high adjustment torque.

The positive rotational engagement between the inner drive sleeve <NUM> and the outer worm gear sleeve <NUM> is desirable to cause translation of the ball stud <NUM>, except when the rotational force applied to the head portion <NUM> exceeds a desired limit, with the limit being less than an applied rotational force that could damage one or more components of the adjuster <NUM>. For example, where the components coupled to the ball stud <NUM>, or the ball stud <NUM> itself, have reached a mechanical limit, such that continued applied rotational force would cause undesirable mechanical slippage/stripping/damage to occur to components between the outer worm gear sleeve <NUM> and the ball stud <NUM>.

To prevent such potential damage the worm input drive <NUM> is clutchable. More particularly, when rotation of the inner drive sleeve <NUM> does not cause the desired rotation of the outer worm gear sleeve <NUM>, such as due to binding of other components coupled to the outer worm gear sleeve <NUM>, the engagement ribs <NUM> are pushed radially inward and if enough pressure is applied, will move out of their respective engagement grooves <NUM>. The engagement ribs <NUM> are allowed to move radially inward due to the sleeve slots <NUM> that provide room for the shaft portion <NUM> to at least partially collapse under the engagement ribs <NUM>. Continued applied rotational force in the same direction will result in continued clutching, preventing damage to adjuster components. Various shapes and sizes of sleeve slots <NUM>, engagement ribs <NUM>, and engagement grooves <NUM> can be utilized, with the shape, size, and/or material hardness determining the desired clutching force limits.

The worm input drive <NUM> has been shown with the tool engaging portion <NUM> in the head portion <NUM> of the inner drive sleeve <NUM>, although in at least some embodiments, the inner drive sleeve <NUM> can be coupled to additional components (e.g., other rods, gears, extenders, etc.) to allow for an alternate, or additional, tool engaging portion that is displaced from and indirectly coupled to the inner drive sleeve <NUM>.

Claim 1:
A fine pitch adjuster (<NUM>) comprising:
a housing (<NUM>);
a wheel gear (<NUM>) positioned within the housing (<NUM>) and coupled to a ball stud (<NUM>), wherein rotation of the wheel gear (<NUM>) provides inward and outward longitudinal translation of the ball stud (<NUM>) relative to the housing (<NUM>); and
a clutching worm input drive (<NUM>) comprising:
an inner drive sleeve (<NUM>) having a shaft portion (<NUM>) and a head portion (<NUM>), the shaft portion (<NUM>) including a plurality of sleeve slots (<NUM>) formed therein and a plurality of engagement ribs (<NUM>) extending longitudinally and radially therefrom; and
an outer worm gear sleeve (<NUM>) rotationally mounted at least partially in the housing (<NUM>) and having worm gear threads (<NUM>) extending radially therefrom, the worm gear threads (<NUM>) coupled at least indirectly to the wheel gear (<NUM>), and an inner chamber (<NUM>) for receiving the shaft portion (<NUM>) therein, the outer worm gear sleeve (<NUM>) including a plurality of grooves (<NUM>) extending longitudinally along the inner chamber (<NUM>) for mating engagement with the plurality of engagement ribs (<NUM>), wherein rotation of the inner drive sleeve (<NUM>) provides clutchable engagement with the outer worm gear sleeve (<NUM>) to rotate the wheel gear (<NUM>),
wherein clutching of the clutchable engagement includes the plurality of engagement ribs (<NUM>) moving radially inward by a partial collapse of the shaft portion (<NUM>) of the inner drive sleeve (<NUM>).