Abstract:
A track lighting fixture includes a first housing half and a second housing half. The first housing half includes a surface, an inner perimeter, a recess in the surface, and mating ramps extending from the inner perimeter. The second housing half includes a surface, a protrusion extending from the surface, and mating arms extending from the surface.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application claims priority from U.S. Provisional Application No. 60/221,563, filed Jul. 28, 2000; U.S. Provisional Application No. 60/221,564, filed Jul. 28, 2000; U.S. Provisional Application No. 60/221,565, filed Jul. 28, 2000; U.S. Provisional Application No. 60/221,567, filed Jul. 28, 2000; U.S. Provisional Application No. 60/221,568, filed Jul. 28, 2000; U.S. Provisional Application No. 60/221,569, filed Jul. 28, 2000; and U.S. Provisional Application No. 60/221,570, filed Jul. 28, 2000, all of which are incorporated by reference. 
     
    
     
       TECHNICAL FIELD  
         [0002]    This invention relates to track lighting systems and more particularly to a housing rotation lock.  
         BACKGROUND  
         [0003]    Track lighting systems allow installation of light fixtures using a single set of track conductors. Track lighting systems can provide light over a wide area and can be used to accentuate specific objects within a room. Thus, track lighting systems are widely used both in private residences as well as in publicly accessible buildings, such as commercial establishments and museums.  
           [0004]    Track lighting systems come in a variety of shapes, sizes, and configurations. More commonly, the track frame is configured as an elongated rectangle or strip. Track lighting systems typically include spot light fixtures that are inserted along the narrow, electrified track frame. One side of the track frame mounts to a ceiling or wall and the side opposite the mounting surface usually has an opening along the length of the track frame for inserting light fixtures. The component of the light fixture that inserts into the track usually provides both an electrical connection with the track conductors and a mechanical connection to secure the fixture.  
         SUMMARY  
         [0005]    In one general aspect, a track lighting fixture includes a first housing half and a second housing half. The first housing half includes a surface, an inner perimeter, a recess in the surface, and mating ramps extending from the inner perimeter. The second housing half includes a surface, a protrusion extending from the surface, and mating arms extending from the surface.  
           [0006]    In other implementations, the track lighting fixture may include one or more of the following features. For example, the protrusion may be configured to fit within the recess and each mating arm may be configured to mate with a corresponding mating ramp when the first housing half is mated to the second housing half.  
           [0007]    The mating ramp may include a first segment that is generally parallel to the inner perimeter and a second segment extending from the first segment and configured to stop the movement of the mating arm when the mating arm is mated with the mating ramp. Each mating arm may have a first segment extending from the surface of the second housing and a second segment extending from the first segment. A surface of the first segment of the mating ramp may be adjacent to a surface of the second segment of the mating arm when the first housing half is mated to the second housing half.  
           [0008]    Mating of the mating arm with the mating ramp may occur by a friction fit mating. The fitting of the protrusion within the recess may cause a positive lock between the first housing half and the second housing half.  
           [0009]    The first housing half and the second housing half may be configured to be mated by rotational movement of the first housing half relative to the second housing half, which may include a non-engagement movement portion between the mating ramp and the mating arm and an engaged movement portion between the mating ramp and the mating arm. The non-engagement movement portion may include the protrusion in contact with the surface of the first housing half. The engaged movement portion may include the protrusion being in contact with the surface of the first housing half and the second segment of the mating arm being engaged with the first segment of the mating ramp. In this manner, the contact between the surface of the first housing half and the protrusion causes the engagement of the second segment of the mating arm with the first segment of the mating ramp to be under compression. The rotational movement of the first housing half relative to the second housing half may further include a non-engaged portion that is between the mating ramp and the mating arm with the protrusion being loosely within the recess and a loose engagement of the second segment of the mating arm with the first segment of the mating ramp.  
           [0010]    The first housing half or the second housing half may include a reflector and the other housing half may include prongs extending from the respective housing half such that the prongs are adjacent to an edge of the reflector when the first housing half is mated with the second housing half. The first housing half and the second housing half may include vent holes configured to vent heat generated by operation of a lamp within the mated first housing shell and second housing shell. The vent holes in the housing halves may be aligned when the first housing shell is mated with the second housing shell.  
           [0011]    In another general aspect, a method of mating the first housing half to the second housing half of the lighting fixture described above includes placing the first housing half against the second housing half and rotating the first housing half relative to the second housing half until the protrusion is within the recess and the mating arm is mated with the mating ramp.  
           [0012]    The track light system includes relatively few parts and is designed for easy and rapid assembly. The track lighting system provides a lower profile with aesthetically pleasing fixtures and components. Another version of the track light system provides a larger, more rigid track frame in applications where additional mechanical strength is necessary, such as, for example, suspended applications.  
           [0013]    The track connector includes contact blocks that integrate the track frames by making both electrical and mechanical connections with the track conductors. The connections between the various components are securely fastened by compressive as well as penetrating forces. Thus, once the track light system is installed, the electrical connections and mechanical integrity are extremely reliable and require little or no maintenance. The track connectors also have a variety of shapes for flexibility in shape and construction of the track system on various surfaces.  
           [0014]    The light fixture interface provides a low profile, quick connect/disconnect device for attaching the track light fixture to the track frame. Once installed, the interface provides a secure mechanical connection and a reliable electrical connection. The interface allows a track light fixture to be removed or adjusted without fear of contact with the electrical conductors.  
           [0015]    The track lighting system is designed to accommodate an array of different light fixtures that can produce a variety of lighting effects. For example, the wedge base track fixture and the rotation lock housing fixture have compact designs and a minimal number of parts, and are suitable for under-cabinet and task lighting applications. The rotation-lock housing fixture has the added benefit of a pivot mechanism that permits rotation of the light source for illumination of a specific area.  
           [0016]    The light fixtures are designed for use with high intensity lamps. Low-voltage halogen light can be used for dramatic emphasis while protecting against fading and light damage. Many of the light fixtures are suitable for use as accent and spotlights as they can be adjusted or aimed by using a pivot mechanism and other aiming features. The pivot mechanism has components that are fastened together in a manner that prevents use and wear from causing the components to separate or become loose. The pivot mechanism also is durable, has aesthetic symmetry as a component of the light fixture, and is designed with a minimal number of parts.  
           [0017]    The light fixture with integral constant tension and rotation stop is light-weight, easy to manufacture, has a minimal number of parts, and resists wear. The wear-resistant feature provides constant tension between the aiming arm and the lamp retaining ring to prevent looseness or laxity between these components. Thus, the lamp retaining ring is rotatable to a fixed position and will maintain that fixed position even after extended use.  
           [0018]    The track light system is designed to accept high wattage loads at 24 volts so that the track network can be very long with a greater number of light fixtures and lamp holders. Installed costs are lower in comparison to either 120-volt track systems with low-voltage lamp holders or to dedicated 12-volt track systems. The effects of voltage drops caused by line losses are reduced in 24-volt systems. Lamp and fixture current also are lower when operated at 24 volts, resulting in more reliable electrical connections. Lamp lumen output and color consistency also are more uniform. Although discussed with reference to low voltage applications, the concepts described herein for track light systems can be applied to other operating voltages as well, such as, for example, 124 volts or higher.  
           [0019]    The track lamp fixtures and holders are miniaturized to perform their lighting tasks with a low profile system. Low-voltage halogen light can be used for dramatic emphasis while protecting against fading and light damage. Lamp holders also are designed with a reduced number of parts to reduce manufacturing costs.  
           [0020]    The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features and advantages will be apparent from the description, the drawings, and the claims. 
       
    
    
     DESCRIPTION OF DRAWINGS  
       [0021]    [0021]FIG. 1 is a perspective view of a track light system.  
         [0022]    [0022]FIG. 2A is a perspective view of a surface channel track network of the track light system of FIG. 1.  
         [0023]    [0023]FIG. 2B is a perspective view of a wire way channel track network of the track light system of FIG. 1.  
         [0024]    [0024]FIG. 3 is an exploded perspective view of a track connector for use with the track network of FIG. 2.  
         [0025]    [0025]FIG. 4 is a bottom view of a mating wing usable with the track connector of FIG. 3.  
         [0026]    [0026]FIG. 5 is an exploded perspective view of a second track connector usable with the track light system of FIG. 1.  
         [0027]    [0027]FIG. 6 is a bottom view of a straight track connector usable with the surface channel track network of FIG. 2A.  
         [0028]    [0028]FIG. 7 is a perspective view of an angled track connector usable with the track network of FIGS. 2A and 2B.  
         [0029]    [0029]FIG. 8 is a perspective view of a flexible track connector usable with the track network of FIGS. 2A and 2B.  
         [0030]    [0030]FIGS. 9 and 10 are exploded perspective views of an interface for use with the track light system of FIG. 1.  
         [0031]    [0031]FIG. 11 is a bottom perspective view of the interface of FIGS. 9 and 10.  
         [0032]    [0032]FIGS. 12 and 13 are perspective views of a constant tension and rotation stop lamp holder.  
         [0033]    [0033]FIGS. 14 and 15 are side views of the constant tension and rotation stop of FIG. 12.  
         [0034]    [0034]FIGS. 16 and 17 are side and perspective views of a lamp holder with a pivot mechanism.  
         [0035]    FIGS.  18 - 21  are exploded perspective views of pivot mechanisms.  
         [0036]    [0036]FIG. 22 is an exploded perspective view of a lamp holder with an integral lens retention spring.  
         [0037]    [0037]FIG. 23 is a perspective view of a housing for the lamp holder with an integral lens retention spring.  
         [0038]    [0038]FIG. 24 is a perspective view of a lens mounting spring for the lamp holder with an integral lens retention spring.  
         [0039]    FIGS.  25 - 27  are cut-away views of the lens mounting spring and the housing.  
         [0040]    FIGS.  28 - 30  are perspective and exploded views of wedge base lamp holders.  
         [0041]    [0041]FIG. 31 shows a top-portion of a retention plug inserted in a stop disk for the wedge base lamp holder.  
         [0042]    [0042]FIG. 32 shows a retention plug and holder for the wedge base lamp holder.  
         [0043]    [0043]FIG. 33 is a perspective view of a rotation lock housing fixture.  
         [0044]    FIGS.  34 - 37  are perspective views of front and rear housings for the rotation lock light fixture.  
         [0045]    [0045]FIG. 38 illustrates assembly of the rotation lock light fixturelamp holder with an integral lens retention spring.  
         [0046]    Like reference symbols in the various drawings indicate like elements. 
     
    
     DETAILED DESCRIPTION  
       [0047]    Referring to FIG. 1, a track light system  100  includes a track network  101 , a connector  102 , an interface  103 , a constant tension lamp arm with integral rotation stop  104 , a lamp holder  105  with a pivot mechanism  106 , a lamp holder  107  with integral lens retention spring, a wedge-base lamp holder  108 , a rotation lock light fixture  109  with a pivot mechanism  110 , and a feed  111 .  
         [0048]    The track light system  100  may be operated at various voltages. For example, the track light system may be operated at 24 volts and 25 amps (600 watts) or at 12 volts and 25 amps (300 watts). Operating at these voltages, the track light system  100  does not require grounding. The track light system  100  may be operated with a variety of power supplies. For example, the track light system  100  maybe operated with 60, 150, or 300 watt electronic power supplies, or with 150, 300, 600, or 1200 watt magnetic power supplies. Power supplies may be designed for operation at various input voltages, such as, for example, 120 volts or 277 volts, with alternating current feed.  
         [0049]    Electronic power supplies are lightweight and relatively small, allowing their use in cabinets and confined areas. Power supplies are designed for tie-in to existing feed locations and can be placed at the start of the track network  101  or at any point along the track network  101 .  
         [0050]    Magnetic power supplies, though larger and heavier, can handle larger loads. These power supplies are available for 120 volt or 277 volt feeds. The wiring used to connect the magnetic power supply to the track network  101  can affect the load carrying capability of the track network system  100 . Boost taps can be used to increase the rated power capability of the system  100 .  
         [0051]    Referring also to FIG. 2A, the track network  101  includes a track frame  112  with an opening  113 , an upper channel  115 , and a lower channel  120 . The lower channel  120  includes a pair of conductors  125 . An open slot  130  extends from the upper channel  115  into the lower channel  120 . The interface  103  (described below with respect to FIG. 3) is designed for insertion through the opening  113  with portions of the interface  103  secured in the upper channel  115  and the lower channel  120  so as to make an electrical connection with the track network  101 .  
         [0052]    The track network  101  comes in various lengths. For example, the track network  101  may come in 2, 4, 6, or 8 foot lengths. Track networks  101  also may be cut to any particular length. Track networks may have different finishes, such as, for example, white, black or silver-metallic finishes.  
         [0053]    In the implementation of FIG. 2A, the track network is configured to be a surface channel track network with minimal size and weight. For example, the surface channel track network may be ⅜ inches high and ¾ inches wide. The surface channel track network  101  may be made from thermoplastic materials. The flexibility of these materials allows the track network  101  to be bent to conform to a non-linear surface. Typical applications for such a track network  101  are under-cabinet, in-cabinet, cove, and strip lighting.  
         [0054]    In another implementation, illustrated in FIG. 2B, the track network is configured to be a wire way track network with more size and weight. For example, the wire way channel track network  101  may be one inch high and one inch wide. The wire way channel track network  101  may be made from materials with additional strength, such as, for example, extruded aluminum. Typical applications for this type of track network  101  are where additional mechanical strength is desired, such as, for example, suspended applications and accent or display lighting. Wire way track networks  101  may be mounted directly to a surface or suspended. The wire way track networks also differ from the surface channel track networks because of the relatively larger size of the upper channel  115  of the wire way track network, which is sized to accommodate conductors or wires to provide power to another part of the track light system.  
         [0055]    The wire way track network accommodates conductors  125  that are insulated from the metal track frame  112  by insulation  135 . Stranded wire, as well as conductors, also may be housed in the track frame  112 .  
         [0056]    The conductors  125  are made of conductive metal materials, such as, for example, copper, nickel-plated copper, or nickel-plated brass. The conductors  125  may have various sizes, such as, for example, 10, 12, or 14 AWG.  
         [0057]    Referring to FIG. 3, the feed  111  includes a housing  202 , a housing screw  204 , a mounting portion  205 , and a body  206 . The mounting portion  205  is used to mount the housing  202  to a ceiling or a wall and includes channels  207  for inserting a screw or nail. The body  206  includes a mating wing  208  with lips  210 , a mating screw  212 , a housing screw hole  214 , channels  216 , and slots  218 .  
         [0058]    Contact blocks  220  are positioned in the channels  216 , which extend through the body  206 . Each contact block  220  includes an opening  222  that extends through the contact block  220  in the same direction as the channel  216 .  
         [0059]    The contact blocks  220  and  262  may be made of materials such as are described in FIG. 2 above with respect to track conductors  125 . A contact retainer  224  partially wraps around the body  206  with a head  226  of the contact retainer  224  inserted into a notch  228  in the slot  218  and a foot  230  of the contact retainer  224  inserted inside the opening  222  of the contact block  220 . The foot  230  on the contact retainer  224  is configured to act as a stop for track conductors  125  that are inserted into the opening  222 .  
         [0060]    The contact block  220  has a threaded rear hole  234  and a threaded front hole  236  through a top surface  238  of the contact block  220 . A rear retaining screw  240  and a flat retaining screw  242  are configured to be threadably inserted into the threaded holes  234 ,  236  and into the openings  222 . The rear retaining screw  240  is threaded into the threaded opening through the slot  218  to fix the foot  230  of the contact retainer to the contact block  220 . The head of the retaining screw  240  contacts an edge of the slot  218  to fix the contact block  220  inside the channel  216 .  
         [0061]    To electrically connect electrical wiring from, for example, a junction box or transformer, and a track network  101  to the feed  111 , the rear retaining screw  240  is loosened and one wire of the electrical wiring is inserted into the opening  222  until the wire rests against the contact retainer  224 . The rear retaining screw  240  then is tightened down into the opening  222  to hold that wire in place in the contact block  220 . The other wire from the electrical wiring is inserted into the other contact block  220  from the same direction and retained in the contact block  220  in the same manner. Then, one conductor  125  from one track network  101  is inserted into the opening  222  from the other direction until the conductor rests against the contact retainer  224 . The front retaining screw  242  then is tightened down into the opening  222  to hold that conductor  125  in place in the contact block  220 . The other conductor  125  from the track network  101  is inserted into the other contact block  220  and retained in the contact block  220  in the same manner. The housing or cover  202  then may be mounted over the body  206 .  
         [0062]    Referring to FIG. 4, the connector  102  has many of the features of the feed  111  and also may include a housing  245  and a removable mating wing  250  with features similar to those of the mating wing  208 , including lips  210  and a mating screw  212 . The removable wing is slidably connected to the body by flared insert tabs  252  that mate with a recess  254  in the body  206 . Because the removable wing  250  is oriented in the opposite direction as the other wing of the body, track network can be mounted to both sides of the connector  102  to connect to track networks and extend the track lighting system. The conductors  125  of each track network  101  are inserted into the openings  222  of the contact block  220  in the same manner described above with respect to FIG. 3.  
         [0063]    Referring to FIG. 5, an end-feed, dual connector  260  holds a pair of dual opening contact blocks  262 . Each contact block  262  includes a pair of dual openings  264 . The dual feed connector has features similar to those of the feed connector  102  described with reference to FIG. 3, including a housing  202 , a housing screw  204 , and a body  206 . The body  206  includes a tongue  208  with wings  210  and a tongue screw  212 . The body  206  also includes a housing screw hole  214  and channels  216 .  
         [0064]    The contact blocks  262  are configured to be inserted in the channels  216 . In this implementation, however, the channels  216  are open at the top and are covered by a plate  266 . The plate  266  has rear screw holes  268 , front screw holes  270 , and a housing screw hole  272 . As in the feed connector  102 , the contact blocks  262  have openings  264  extending through the contact blocks  262  in the same direction as the channels  216 . The contact blocks  262  have dual threaded rear holes  234  and threaded front holes  236  extending from the top surface  238  into the opening  264 .  
         [0065]    Rear retaining screws  240  extend through the rear screw holes  270 , into the rear holes  234 , and into the opening  264 . Similarly, the front retaining screws  242  extend through the front screw holes  270 , into the front holes  236 , and into the opening  264 . The plate  266  is positioned over the body and retained by clamp arms  274  that extend from the plate  266  into notches  276  in the body  206 .  
         [0066]    The body  206  also includes a knock-out  278 . The knock-out is removed to provide a knock-out hole  280  for electrical wiring (not shown). An aperture  282  in the body  206  also can be used for electrical wiring (not shown). The wiring then is inserted into the openings  264  and the rear screws  240  are tightened down to fix the wiring to the contact block  262 .  
         [0067]    A variety of configurations for a feed connector may be employed. For example, the feed connector  260  as shown in FIG. 5 may be configured as a straight joiner connector for the wire way channel. Referring to FIG. 6, a straight joiner connector  284  includes a body  206  with two sets of mating wings  208 , channels  216 , contact blocks  220 , and plates  266 . Front retaining screws  240  and rear retaining screws  242  engage electrical wires  286  and other electrical components inserted in the openings  264  in the contact blocks  262 .  
         [0068]    Referring to FIG. 7, in another configuration, the feed connector is configured as a right-angle joiner connector  288 . Referring to FIG. 8 the feed connector also can be configured as a flexible feed connector  290  that includes a flexible mid-section  292 . The connectors  288  and  290  have features of the connectors  102 ,  245 , and  260  such that electrical wires can be connected to the connectors  288 ,  290 . Other implementations of connectors include J-box feed connectors for use in mounting to a single gang wall or ceiling-mount junction box, end-feed connectors for starting a run, and T-bar and J-box canopy feed connectors for starting a run on a T-bar ceiling installation. Referring to FIG. 9, a track fixture interface  103  includes a cap  302 , contact clips  304 , jackets  306 , screws  308 , a top  310 , a housing  312 , a pair of springs  314 , a base  316 , a collar  318  with a lip  319 , and an electrical wire  320 . The screws  308  and the springs  314  are isolated from the contact clips  304  by plastic cylindrical walls  344  that are molded in place (FIG. 10). The cap  302  includes a head  326  and two arms  328  that terminate in flared hooks  329 . The cap  302  is retained in place by a one-way latching mechanism that provides advantages over other retention means, such as a screw or a rivet, because the cap is easily inserted in place and does not require additional components. The contact clip  304  includes a contact head  330  and a foot  332 . The top  310  includes a notch  333 , insert wings  334 , a pair of screw holes  336 , and a channel  338 . The base includes posts  340  and an aperture  342 .  
         [0069]    Referring also to FIG. 10, the springs  314  fit over the posts  340  on the base  316  and inside the pair of molded cylinders  344  in the housing  312 . In this manner, the base  316  is slidable within the housing  312 , with the spring  314  resisting insertion of the base  316  within the housing  312 . The stiffness of the springs  314  can be adjusted to vary the resistance caused by the springs.  
         [0070]    Referring also to FIG. 11, the foot  332  of each contact clip  304  is inserted through the channel  338 . The arms of the cap  302  then are inserted into the channel  338  until the head  326  is flush with the notch  333  above the insert wings  334 . In this position, the hooks  329  extend through the channel  338  and expand outward into ledges  346  at the end of the channel  338 , to lock the cap  302  in place.  
         [0071]    Referring again to FIG. 9, the collar  318  is placed inside the base  316  with the lip  319  directed upward toward the cap  302 . The collar  318  is allowed to slide through the aperture  342  in the base  316  until the lip  319  contacts the inside surface of the base  316  surrounding the aperture. The electrical wire  320  is inserted through the collar  318  and extends through the aperture  342  in the base  316  and housing  312 . Conductors in the electrical wire  320  then are spliced to the foot  332  of the contact clip  304  by placing the jacket  306  over the conductor and the foot  332  of the contact clip  304 , and tightly crimping the jacket  306 .  
         [0072]    The interface  103  provides an electrical and mechanical connection between the track network  101  and a track light fixture. Installing the interface  103  into the track network  101  includes inserting the interface  103  into the opening  113  with the insert wings  334  extending through the slot  130  of the track frame  110  with the head  330  of the contact clip  304  in the lower channel  120  and the insert wings  334  in the upper channel  115 . The interface  103  is rotated approximately 90 degrees relative to the track frame  110 , which tightly wedges the insert wings  334  into the upper channel  115  and causes the head  330  of the contact clip  304  to make an electrical connection with the track network conductor  125 . The springs  314  force the housing  312  against the track network  101  with tabs or rotation stops  348  on the housing  312  inserted into the opening  113  in the track frame  110 . The wing  334  and stops  348  prevent accidental separation or dislodgement of the interface  103  from the track network. The interface  103  provides advantages, such as being configured from fewer parts than conventional connectors or interfaces. Moreover, the interface  103  is advantageously smaller than conventional connectors or interfaces.  
         [0073]    Referring to FIGS. 12 and 13, a constant tension and rotation stop light fixture  104  includes a lamp retaining ring  405 , a lamp retaining arm  410 , and an aiming arm  415 . The lamp retaining arm  410  is attached to the aiming arm  415  with a rivet  420  and includes a pair of resilient fingers  425 . The aiming arm  415  includes a base  430  that includes an opening  435  and a stop  440 . The lamp retaining ring  405  includes a body  445  that has a perpendicularly directed lip  450 .  
         [0074]    [0074]FIG. 13 shows a light bulb  453  installed in the adjustable lamp arm  104  of FIG. 12. The light bulb  453  is positioned between the lip  450  and the fingers  425 , with the front of the light bulb facing the lip  450 . The pair of resilient fingers  440  exert pressure against the light bulb  453  to hold it against the lip  450 .  
         [0075]    The opposing end of the retaining arm  410  includes a foot  455  with sloped sides  460 .  
         [0076]    The foot  455  extends through a slot  465  in the retaining ring  405 . As the aiming arm  415  is rotated in a circle around the axis of the rivet  420 , it comes into contact with the sides  460  of the foot  455 , which blocks further rotational motion in the same direction. Thus, the foot  455  acts as a rotation stop.  
         [0077]    The aiming arm  415  and the lamp retaining arm  410  are mounted to the lamp retaining ring  405  using the rivet  420  around which the aiming arm  415  can pivot. Referring also to FIG. 14, the rivet  420  includes a head  470 , a shank  475 , and a hollow  480 . The shank  460  of the rivet  420  is inserted through a hole  485  in the aiming arm  415 , an opening in a tension washer  490 , and a hole  495  in the retaining ring  405 .  
         [0078]    Referring also to FIG. 15, the rivet  420  is crimped to attach the aiming arm  415  to the lamp retaining arm  410 , which causes the shank  475  in proximity to the hollow  480  to mushroom outward and flattens the shank  475  against the inside of the retaining ring  405 . Crimping the rivet  420  also applies a compressive force to the tension washer  490  to reduce the cross sectional thickness, which leaves the washer  490  under a compressive force that the washer  490  resists by pressing outwardly against the aiming arm  415 .  
         [0079]    The aiming arm  415  may be rotated relative to the retaining ring  405  and will maintain a fixed position because of the tension that is exerted between the aiming arm  415  and the retaining ring  405  as the tension washer  490  attempts to expand to its normal shape. Thus, rotational motion and other uses that would otherwise cause laxity or space between the aiming arm  415  and the retaining ring  405  are avoided by the constant expansive force from the tension washer  490 . In this manner, the tension washer  490  effectively allows the aiming arm  415  to be rotated to a desired, fixed position and to maintain that fixed position relative to the retaining ring  405 .  
         [0080]    Referring to FIGS. 16 and 17, a lamp holder with the pivot mechanism  106  includes a lamp retaining ring  505 , a lamp retainer  5   10 , an extension arm  515 , a connecting arm  517 , a positioning handle  519 , and the pivot mechanism  106 . The connecting arm  517  and the lamp retainer  510  are mounted to the lamp retaining ring  505 . The lamp retainer  510  includes a pair of resilient fingers  525 . The extension arm  515  includes a base  530  that has an opening  535  and a stop  540 . The lamp retaining ring  505  has a perpendicularly directed lip  550  around part of the inner-circumference of the ring  505 .  
         [0081]    The extension arm  515  has a ribbed area  570  and the positioning handle  519  has a grip dome  580 . The grip dome  580  is made of rubber or other insulating material that does not easily conduct heat.  
         [0082]    An electrical wire  585  connected to a light bulb  555  is inserted through the opening  535  and connected at the other end to the track fixture interface  103  described above with respect to FIG. 9. With the track fixture interface  103 , the lamp holder can be moved along the track  101  to provide illumination where desired.  
         [0083]    Referring to FIGS. 18 and 19, the pivot mechanism  106  includes a screw  610 , a bushing  615 , a compression washer  620 , a pivot holder  625 , a washer  630 , and an arm pivot  635 . The configuration of the pivot mechanism  106  is such that it prevents the screw  610  from backing out after repeated use. Thus, the pivot mechanism  106  also can be used in other applications that require a hinge with rotational motion that must not loosen over time and with repeated use.  
         [0084]    The bushing  615  has a head  640  and a base  645 . The head  640  has a bevel  650  and a hole  655  that pass through the center of the head  640  and continue through the base  645 . The base  645  has two flat areas  660  at the end opposite the head  640 . The pivot holder  625  includes a circular lip  665  (FIG. 19) with a smaller diameter than the outside surface of the pivot holder  625  extending around a portion of the pivot holder  625 . A circular opening  670  extends through the pivot holder  625 . The arm pivot  635  has a recess  675  that circles the inside diameter of the arm pivot  635  and a channel  680  extending about halfway into the arm pivot  635 . The channel  680  is circular with two flat sides  685 . The bottom of the channel  680  includes a threaded section  690  that extends deeper into the arm pivot  635  without penetrating the wall of the arm pivot  635 .  
         [0085]    The pivot mechanism  106  is assembled by placing the washer  630  into the recess  675  of the arm pivot  635 . The pivot holder  625  then is placed against the arm pivot  635  such that the lip  665  extending from the pivot holder  625  fits within the inner diameter of the washer  630 . The bushing  615  is inserted through the compression washer  620 , into the opening  670  in the pivot holder  625 , and then into the channel  680  in the arm pivot  635 . In this position, the flat areas  660  on the bushing  615  mate with the flat sides  685  in the channel to prevent rotation of the bushing  615 . Next, the screw  610  is inserted into the hole  655  and is threaded into the threaded section  690  at the bottom of the channel  680  in the arm pivot  635  until the top of the screw  610  is flush with the top edge of the bevel  650 .  
         [0086]    Referring to FIGS. 20 and 21, another implementation of a pivot mechanism  691  includes the screw  610 , the compression washer  620 , a base pivot  692 , and a lamp pivot  693 . The base pivot  692  includes the bevel  650 , the hole  655  that extends through the base pivot  692 , and a protruding rotation stop  694 . The end of the base pivot  692  nearest to the lamp pivot  693  includes the circular lip  665  with a smaller diameter than the outside surface of the base pivot  692 . The base pivot  692  is connected to a base plate  695  with a hole  696 .  
         [0087]    The lamp pivot  693  has a recess  675  (FIG. 20) that circles the inside diameter of the lamp pivot and a threaded  690  extending into the lamp pivot. The lamp pivot  693  also includes a protruding rotation stop  697 . The arm pivot  625  is connected to a lamp housing  698 .  
         [0088]    The pivot mechanism  691  is assembled by placing the compression washer  620  into the recess  675  of the lamp pivot  693 . The base pivot  692  then is placed against the lamp pivot  693  such that the lip  665  extending from the base pivot  692  fits within the recess  675 . Next, the screw  610  is inserted through the hole  655  and is threaded into the threaded section  690  in the lamp pivot  693  until the top of the screw  610  is flush with the top edge of the bevel  650 .  
         [0089]    As shown in FIG. 22 a lamp holder with the integral lens retention spring  107  includes a housing  710 , a lens  715 , a lens frame  720 , lens mounting springs  725 , and mounting screws  727 . The mounting springs  725  are mountable to the lens frame  720  and are configured to retain the lens  715  in the lens frame and to attach the lens frame  720  to the housing  710 . The housing  710  includes a wiring hole  730 , fins  735 , a mounting platform  740 , and cut-out areas  745 . As illustrated in FIG. 23, the housing  710  also includes a cavity  743  with recessed channels  747 . As described below, the recessed channels  747  are sized to receive the lens mounting springs  725  when the housing  710  is mounted to the lens frame  720 .  
         [0090]    As shown in FIG. 22, the lens frame  720  is a circular ring with a lens aperture  750 , retaining tabs  755  and a mounting notch  760  with a hole  765  in a wall of the lens frame. The lens  715  may be made of transparent or translucent materials, such as, for example, plastic or glass. Lens  715  may have color filter and/or optical characteristics. For example, lens  715  may be a gel filter or dichroic filter in colors such as red, yellow, ultraviolet, amber, green, blue, or daylight. Optical filters may include diffuse, sand-blasted, soft focus, prismatic spread, or linear spread lenses.  
         [0091]    Referring to FIG. 24, the lens mounting spring  725  includes a foot or first section  770 , a seat or second section  775  with a screw hole  780 , an elbow or third section  785 , a mounting arm or fourth section  790 , and a hook or curved section  795 . The second section  775  is generally perpendicular to the first section  770 . The third section  785  is generally perpendicular to the second section  775 . The fourth section  790  extends away at an angle from the third section  785 . The hook or curved section  795  is configured to ease and direct sliding of the mounting spring into the housing  710 . The lens mounting spring  725  attaches to the lens frame  720  by inserting the seat  775  of the lens mounting spring  725  into the mounting notch  760  in the lens frame  720 . The mounting screws  727  then are passed through the screw hole  780  in the seat  775  and threaded into the hole  765  (FIG. 22) to secure the lens mounting springs  725  to the lens frame  720 . The holes  765  can be threaded or non-threaded threaded when, for example, the screws  777  are self-tapping.  
         [0092]    [0092]FIG. 25 shows a cut-away view of the lens mounting spring  725  secured to the lens frame  720 . As shown, a gap  781  is formed between the foot  770  of the lens mounting spring  725  and a side wall  782  of the mounting notch  760 .  
         [0093]    Referring to FIG. 26, the lens  715  is pushed down into the lens frame  720  until the lens contacts the retaining tabs  755  and causes the lower portion of the foot  770  to spring upward and back toward the side wall  782 . The lens  715  then is pushed away from the side wall  782  by the foot  770  and down into the lens aperture  750  until the lens contacts the retaining tabs  755 . The retaining tabs  755  limit movement of the lens  715  in a first direction and the mounting springs  725  limit the movement of the lens in a second direction. Thus, the lens  715  is fixed inside the lens frame  720  by the tension against the lens  715  by the foot  770 . Finally, referring to the cut-away view in FIG. 27, the lens frame  720  is attached to the housing  710  by pushing the mounting arms  790  and hooks  795  into the channels  747  in the cavity  743  of the housing  710 . Tension created by bowing in a portion of the mounting arms  790  against the channels  747  fixes the lens frame  720  to the housing  710 .  
         [0094]    Referring to FIGS.  28 - 31 , a wedge-base lamp holder  108  includes a holder  810 , one or two reflectors  812 , a retention plug  814 , and electrical contact clips  816 . For example, FIG. 28 illustrates the lamp holder  108  with two reflectors  812  and FIG. 29 illustrates the lamp holder with one reflector  812 .  
         [0095]    Referring to FIG. 30, the holder  810  includes a body  818 , a shaped channel  820 , an open channel  822 , a stem  824 , a stop disk  826 , and a rotation disk  828 . In the wedge base lamp holder  108  with one reflector  812 , the shaped channel  820  extends through one end  832  of the body  818 . The end of the shaped channel  820  has an angled ramp  830 . The open channel  822  extends from the open end  832  to a channel termination  834  near the opposite end of the body  818 . The open channel  822  extends upward through the stem  824 , the stop disk  826 , and the rotation disk  828 .  
         [0096]    The holder  810  also includes two vertical alignment grooves  836  that extend from the top of the stem  824  downward to the shaped channel  820 . The holder also includes locking grooves  838  in the stop disk  826  that extend from the stem  824  to the outer edge of the stop disk  826 .  
         [0097]    The reflector  812  has an insertion end  840  with two insertion prongs  842 . The reflector also has a semi-circular insertion hole  844  near the insertion end  840 . The insertion hole  844  is used to mount the reflector  812  to the body  818 , as described below.  
         [0098]    The retention plug  814  includes a cap  846 , a base  848 , an insert arm  850 , and a retaining arm  852 . The base  848  includes two insert rails  854  that extend from the cap  846  to approximately midway down the base  848 . The base  848  also includes an insert tab (not shown) on the side opposing the cap  846 .  
         [0099]    The insert arm  850  includes a retaining tab  856  that branches downward from the end of the insert arm  850 . The retaining arm  852  includes two locking rails  858  that extend from the base  848  to the end of the retaining arm  852 . Each locking rail  858  has a flat top edge and an angled bottom edge. The retaining  852  arm also includes a retaining tab  856  that branches downward from the end of the retaining arm  852 .  
         [0100]    Each contact clip  816  includes a tongue  860 , a riser  862 , contact fingers  868 , and a coupling wall  870 . The contact fingers  868  include angled portions  872  at the ends with a section of the contact finger  868  bent downward and another section of the contact finger  868  bent upward.  
         [0101]    The wedge-base lamp holder  108  is assembled by inserting the contact fingers  868  on the contact clips  816  into the shaped channel  820 . The tongues  860  are placed facing outward and resting in recesses  874  at the top of the stem  824 . The reflectors  814  then are placed on top of the base with the insertion ends  840  facing the center of the holder  810 . The insertion prongs  842  on the reflector are slid into insertion grooves  876  located at the bottom of the stem  824  where the stem meets the body  818 .  
         [0102]    Next, the retention plug  814  is inserted down into the holder  810  with the insert arm  850  facing the channel termination  834  and the retention arm  852  facing the open end  832 . The insert rails  854  on the retention plug  814  are aligned with and inserted into the alignment grooves  836  in the stem  824  of the holder  818 . Also, the retaining tabs  856  on the insert arm  850  and the retaining arm  852  of the retention plug  814  slide into the insertion holes  844  in the reflectors  812 .  
         [0103]    As illustrated in FIGS. 31 and 32, as the retention plug  814  slides downward into the holder  810 , the locking rails  858  on the retention plug  814  lock into the stop grooves  838  on the stop disk  826  and the insert tab or extension  882  on the base  848  fits into a notch or slot  880  in the bottom of the shaped channel  820 . Inserting the extension  882  within the base slot  880  limits the movement of the retention plug  814  relative to the body  818 .  
         [0104]    The wedge-base lamp holder  108  is installed in the track network in a manner similar to that of the interface  103  shown in FIG. 9. The wedge-base lamp holder  108  is installed into the track network  101  with the cap  846  facing the track network  101  and is inserted into the opening  113 . The tongues  860  of the contact clips  816  are placed in the lower channel  120  and the rotation disk  828  is placed in the upper channel  115 . The stop disk  826  rests on the track frame  110  above the opening  113  to prevent over-insertion of the wedge-base lamp holder  108  in the track network  101 . The wedge-base lamp holder  108  is rotated approximately 90 degrees relative to the track frame  110 , tightly wedging the rotation disk  828  into the upper channel  115  and causing the tongues  860  of the contact clip  816  to make an electrical connection with the track network conductors  125 .  
         [0105]    Referring to FIG. 33, a rotation lock light fixture  109  includes a front housing  905 , a rear housing  910 , a pivot mechanism that operates in the same way as the pivot mechanism  106  described above with respect to FIG. 18, an electrical wire  907 , and an interface  103  (as described above with respect to FIG. 9). The rotation lock light fixture  109  is useful in applications such as under cabinet or cove lighting. For example, the light fixture can be pivoted to illustrate the wall behind and underneath a cabinet. It also can be used to illustrate a work area under the cabinet.  
         [0106]    Referring to FIG. 34, the front housing  905  includes a lens  912 , a lens aperture  914 , a front lip  916 , a front edge  918 , a front cavity  920 , engagement arms  922 , vents  924 , and ridges  926 . Referring also to FIG. 35, the rear housing  910  includes a rear lip  928 , engagement platforms  930 , a rear edge  932 , a rear cavity  934 , reflector braces  936 , posts  938 , screw mounts  940 , a contact platform  942 , vents  944 , an arm  946 , and a portion of the pivot mechanism  106 . The front housing  905  and the rear housing  910  are configured to be mated, as described below. The mated housings  905  and  910  are further configured such that the vents  924  and  944  on the respective housings are aligned for air circulation and cooling within the mated housing  905 ,  910 . For example, as heated air rises and passes through the vents  924  in the front housing  905 , cool air will be pulled into the vents  944  in the rear housing  910 . However, the vents  924  and  944  can be configured in other arrangements to cause the air to pass laterally through the housings  905 ,  910  before passing out of the housings. Moreover, the number and shape of the vents  924  and  944  can be varied for functional and decorative purposes.  
         [0107]    Referring to FIG. 36, a contact block  950  is mounted on the contact platform  942  of the rear housing  910 . The contact block  950  has a wiring clip and wiring holes (not shown) for connection to external electrical wiring. The contact block  950  also has mounting holes  952  for mounting the contact block  950  to the rear housing  910  and bulb insert holes  954  for inserting light bulb conductors into the contact block  950 .  
         [0108]    Referring to FIG. 37, the fixture  109  also includes a reflector  956  and a light bulb  958  installed in the rear housing  910 . The reflector  956  includes a recess  960 , a contact opening  962 , brace holes  963 , and mounting holes  964 . The reflector  956  is prepared for mounting to the rear housing  910  by aligning the brace holes  963  with the reflector braces  936  on the rear housing  910  and putting the posts  938  into the brace holes  963 . The contact block  950  and the reflector  956  are attached to the rear housing with screws  966  that are inserted into the mounting holes  964  on the reflector  956  and inserted into the mounting holes  952  on the contact block  950 . The screws then are threaded down into the screw mounts  940  on the rear housing  910 . Next, conductor tips  968  on the light bulb  958  are passed through the contact opening  962  on the reflector  956  and inserted into the bulb insert holes  954  on the contact block  950 .  
         [0109]    Referring to FIG. 38, the fixture  109  is assembled by aligning the engagement arms  922  on the front housing  905  with the engagement platforms  930  on the rear housing  910 . The front housing  905  and the rear housing  910  then are pressed together as represented by Arrow A so that the front lip  916  overlaps the rear lip  928  and the front edge contacts the rear edge. The front housing  905  is then rotated in a clockwise direction as represented by Arrow B while the rear housing  910  is held in a fixed position until the engagement arms  922  are locked into the engagement platforms  930 .  
         [0110]    A number of implementations have been described. Other implementations are within the scope of the following claims.