Abstract:
A forearm extension is provided for use in an extension arm that adjustably mounts an electronic device to a support mount, and conceals cables to and from the device within the forearm extension. The forearm extension includes a body having an interior region and first and second ends. A first end coupling is formed by at least a first wall disposed at a first end of the body. The first wall defines an enclosed region having at least one open end. The first end coupling includes a slot formed in the first wall so that the open end of the first end coupling and the interior region of the body are in communication with each other through the slot. The slot is adapted for passage of a cable therethough. A second end coupling is formed by at least a second wall disposed at a second end of the body for coupling to the electronic device.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This patent application is a divisional application of patent application Ser. No. 09/406,006 filed on Sep. 24, 1999 now U.S. Pat. No. 6,409,134 which claims priority under 35 U.S.C. §119(e) from Provisional Patent Application No. 60/138,120 filed on Jun. 7, 1999. 

   BACKGROUND OF THE INVENTION 
   This invention relates to an arm apparatus for mounting electronic devices, and more specifically to an extension arm suitable to mount a flat-screen electronic peripheral device, such as a computer monitor or a television, the extension arm having a system for managing the cables to and from the flat-screen electronic device. 
   Adjustable extension arms for mounting electronic peripheral devices, such as a computer monitor or a television, are well known in the prior art. However, due to recent advances in flat-screen technology, there is a demand for adjustable extension arms that are particularly suited for use with flat-screen devices, such as flat-screen computer monitors and televisions. 
     FIGS. 1-7  are assembly drawings of an extension arm  10  for mounting a peripheral device, in accordance with the prior art. As shown in  FIG. 1 , the main elements of the extension arm  10  are a first endcap  12 , an upper channel  14 , a lower channel  16 , a second endcap  18 , and a forearm extension  20 . The first endcap  12  has an endcap shaft  22  that is pivotably attachable to a rigid support mount (not shown), such as an orifice sized to accept the endcap shaft  22  or a track configured and sized to engage the grooves on endcap shaft  22 . The first endcap  12  is pivotably coupled via pins  24  to both the upper channel  14  and the lower channel  16 . The opposite ends of the upper channel  14  and the lower channel  16  are pivotably coupled via pins  24  to the second endcap  18 . The second endcap  18  is coupled to the forearm extension  20  via a forearm extension pin  92 . The forearm extension  20  has a vertically disposed hole  26  therethrough for accepting a device mount (not shown) such as a tilter, platform or other apparatus. The combination of the upper and the lower channels  14 ,  16  and the first and the second endcaps  12 ,  18  form an adjustable parallelogram that permits a device coupled to the forearm extension  20  to be raised and lowered to a desirable height. The parallelogram retains its position by employing a gas spring  28 , which is pivotably and adjustably attached to the first endcap  12  and the upper channel  14 , as will be further described below. Generally, the gas spring  28  is sized so as to have a fixed length until an upward or downward force is exerted at the second endcap  18  that exceeds the gas spring&#39;s designed resistance. Thus, the gas spring  28  causes the parallelogram to retain its position when the only force exerted at the second endcap  18  is the weight of the device, but permits the parallelogram to be adjusted when a user pushes the device coupled to the forearm extension  20  up or down. 
     FIG. 2  illustrates a side view of the first endcap  12 , having the endcap shaft  22  disposed on a first end  30  of the first endcap  12 . To provide a rigid connection between the two pieces, the endcap shaft  22  is typically machined from steel and is inserted into the first end  30  during the casting process of the first endcap  12 . The endcap shaft  22  has a hole  32  formed in an end of the endcap shaft  22  that is inserted into the first endcap  12 . The first endcap  12  is typically fabricated from cast aluminum. The first endcap  12  also has a second end  34  having a hole  36  disposed therethrough. Disposed within the first endcap  12  is a threaded rod  38 . A first end  40  of the threaded rod  38  is inserted into the hole  32  at the base of the endcap shaft  22 . A second end  42  of the threaded rod  38  is aligned with the hole  36  and is held in place by a clip  44 . The clip  44  is fastened to an inner surface of the first endcap  12  by screws  46 . 
   Threadedly mounted on the threaded rod  38  is a clevis  48 .  FIG. 3  illustrates a sideview of the clevis  48  including a tapped hole  50  in the center thereof. The tapped hole  50  receives the threaded rod  38 , as shown in FIG.  2 . At a first end of the clevis  48  is a pair of fastening members  52 ,  54  to which are fastened one end of the gas spring  28 . A second end  56  of the clevis  48  is configured to slidably engage a track  58  which is integrally molded in the first endcap  12  (see FIG.  2 ). The second end  42  of the threaded rod  38  is configured to be engaged by a hex-shaped key which is inserted through the hole  36  when the second end  42  is properly aligned with the hole  36 . The hex-shaped key is employed so as to rotate the threaded rod  38  along its axis of rotation. When the threaded rod  38  is rotated along its axis of rotation, the clevis  48  moves along the length of the threaded rod  38  in a direction that corresponds to the direction which the hex-shaped key is turned. This movement of the clevis  48  permits the gas spring  28  to be adjusted. 
   FIGS.  4 ( a ) and  4 ( b ) illustrate the upper channel  14 , which comprises channel bottom  60  from which extend two channel sidewalls  62 . Channel bottom  60  and sidewalls  62  are typically stamped from 13 gauge steel sheet in order to give the upper channel  14  a desired degree of structural rigidity. At each of the ends of the channel bottom  60 , a semi-circular region  64  of the sidewalls  62  is cut out to accommodate cold-rolled steel rollers  66 , which have a hole  68  therethrough for receiving the pins  24 . The rollers  66  are rigidly attached to the upper channel  14  by MIG welding along the edge of the semi-circular cut out region  64  and along the ends of the channel bottom  60 . 
   Additionally, the upper channel  14  comprises stiffener  70 , which is welded to an inner surface of the channel bottom  60 . Besides providing additional structural rigidity to the upper channel  14 , the stiffener  70  has a hole disposed at one end with a threaded ball stud  72  placed within the hole and fixed in place by a nut  74 . The ball stud  72  is configured and sized to receive one end of the gas spring  28 . The longitudinal centerline  76  of the upper channel  14  is illustrated in FIG.  4 ( b ). 
   FIGS.  5 ( a ) and  5 ( b ) illustrate the lower channel  16  which comprises a channel bottom  78  from which extend two channel sidewalls  80 . As with the upper channel  14 , the channel bottom  78  and sidewalls  80  are typically stamped from 13 gauge steel sheet, which is relatively heavy in order to give the lower channel  16  a desired degree of structural rigidity. At opposite ends of the channel bottom  78 , a semi-circular region  82  of the sidewalls  80  is cut out to accommodate cold-rolled steel rollers  84 , which have a hole  86  therethrough for receiving the pins  24 . The rollers  84  are rigidly attached to the lower channel  16  by MIG welding along the edge of the semi-circular cut out region  82  and along the ends of the channel bottom  78 . The longitudinal centerline  88  of the lower channel  16  is illustrated on FIG.  5 ( b ). 
     FIG. 6  illustrates the second endcap  18 . Unlike the first endcap  12 , the second endcap  18  does not have an endcap shaft, nor does it have a clevis assembly for attachment to the gas spring  28 . Instead, the second endcap  18  has a hole  90  disposed in a bottom end for receiving the forearm extension pin  92 , and a hole  94  in a side for inserting a pin  96  into the forearm extension pin  92 , as illustrated in FIG.  1 . 
     FIG. 7  illustrates the forearm extension  20  having the forearm extension pin  92  welded thereto. The forearm extension pin  92  has a hole  98  formed in an upper end to receive the pin  96 . The forearm extension  20  is configured to be pivoted around the forearm extension pin  92 , and is held in place within the second endcap  18  by the pin  96  which penetrates the hole  94  of the second endcap  18  and the hole  98  of the forearm extension pin  92 . 
   Extension arms  10  of the prior art, such as the one shown in  FIGS. 1-7  and others like it, are ill-suited for flat-screen monitors and televisions, in that they are bulky and cumbersome. Moreover, due to the configuration of its various parts, extension arms  10  of the prior art cannot be flattened against a mounting surface so that the entire extension arm  10  is hidden behind the flat-screen device when the device is substantially flush with the mounting surface. Furthermore, the extension arms  10  of the prior art are not designed so as to enable the cables to and from a device to be substantially hidden, and thus protected, within the extension arm  10  itself. Additionally, the extension arms  10  of the prior art are costly to manufacture and difficult to assemble. 
   Thus, there is a need for an extension arm suitable to mount a flat-screen electronic peripheral device, such as a computer monitor or television, that is inexpensive and easy to manufacture and assemble, that permits a flat-screen device to be mounted substantially flush with the mounting surface, and that enables the cables to and from the flat-screen device to be substantially hidden from view within the extension arm and thus protected from the elements. 
   SUMMARY OF THE INVENTION 
   The present invention, in accordance with one embodiment, relates to an extension arm suitable for mounting a flat-screen electronic peripheral device, such as a computer monitor or television. The extension arm is inexpensive and easy to manufacture and assemble, permits a flat-screen device to be mounted substantially flush with a mounting surface, and enables the cables to and from the flat-screen device to be substantially hidden from view within the extension arm. 
   According to one embodiment of the invention, the extension arm comprises a first and a second endcap, an upper and a lower channel, and a forearm extension. Each endcap has a shaft. The shaft of the first endcap is pivotably rotatable in a support mount, such as a wall, desk or pole mount. The shaft of the second endcap is rotatably coupled to the forearm extension. 
   The upper channel and the lower channel have at opposite ends integrally cast rollers. The rollers are pivotably attached to the respective endcap. The upper and lower channels and the endcaps form an adjustable parallelogram. The shape of the parallelogram is retained by a gas spring. A first end of the gas spring is attached to a ball stud mounted in the upper channel. A second end of the gas spring is adjustably mounted to the first endcap. 
   The forearm extension is a U-shaped channel with a first coupling disposed at one end for rotatably coupling to a tilter, a platform or other means for supporting a flat-screen device. The forearm extension has a second coupling disposed at the other end for rotatably coupling to the shaft of the second endcap. 
   The first endcap also includes a clevis pivotably attached to the second end of the gas spring and a threaded rod threadedly engaging the clevis, such that the clevis slides within the first endcap when the rod rotates around its axial centerline. The threaded rod is rotatably secured within the first endcap by a retainer clip and a pair of screws. 
   A cable can be substantially hidden from view by being disposed within the extension arm. The cable is disposed within the lower channel, the second endcap and the forearm extension. The lower channel includes a cable channel formed in a lower surface thereof so that the cable can be inserted within the lower channel. The cable is held in place within the lower channel by a cable cover which engages the cable channel. The second endcap has a hollow shaft so that the cable can be fed through the shaft to the forearm extension. The second coupling of the forearm extension has a hole in an interior wall so that the cable can be disposed through the hole and into the U-shaped channel. The cable is held within the U-shaped channel by a cable clip. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings, which are incorporated in and form a part of the specification, illustrate the embodiments of the present invention and, together with the description, serve to explain the principles of the invention. 
       FIG. 1  is an assembly drawing of an extension arm for mounting a computer monitor, in accordance with the prior art; 
       FIG. 2  illustrates a first endcap of an extension arm, in accordance with the prior art; 
       FIG. 3  illustrates the clevis assembly of an extension arm, in accordance with the prior art; 
       FIGS. 4   a  and  4   b  illustrate the upper channel of an extension arm, in accordance with the prior art; 
       FIGS. 5   a  and  5   b  illustrate the lower channel of an extension arm, in accordance with the prior art; 
       FIG. 6  illustrates a second endcap of an extension arm, in accordance with the prior art; 
       FIG. 7  illustrates a forearm extension of an extension arm, in accordance with the prior art; 
       FIG. 8  is an exploded assembly drawing of an extension arm having an interior cable management system for adjustably mounting a flat-screen device to a support mount, according to one embodiment of the invention; 
       FIG. 9  is a side view of an extension arm with an interior cable management system; 
       FIGS. 10   a-d  illustrate several views of a first endcap, in accordance with one embodiment of the invention; 
       FIGS. 11   a-d  illustrate several views of an upper channel, according to one embodiment of the invention; 
       FIGS. 12   a-e  illustrate several views of a lower channel, according to one embodiment of the invention; 
       FIGS. 13   a-c  illustrate several views of a partially enclosed housing of a second endcap, according to one embodiment of the invention; 
       FIGS. 14   a-b  illustrates several views of a shaft assembly of a second endcap, according to one embodiment of the invention; 
       FIG. 15  illustrates an assembled second endcap according to one embodiment of the invention; 
       FIGS. 16   a  and  16   b  illustrate a forearm extension, in accordance with one embodiment of the invention; 
       FIGS. 17   a-b , illustrate several views of a bushing used in a second female coupling of the extension arm illustrated in  FIGS. 16   a-b,    
       FIG. 18  illustrates a forearm extension, in accordance with one embodiment of the invention; and 
       FIG. 19  illustrates a forearm extension, in accordance with one embodiment of the invention. 
   

   DETAILED DESCRIPTION 
   In describing the preferred embodiments of the invention illustrated in the drawings, specific terminology will be used for the sake of clarity. However, the invention is not intended to be limited to the specific terms so selected, and it is to be understood that each specific term includes all technical equivalents that operate in a similar manner to accomplish a similar purpose. 
   With reference to the drawings, in general, and  FIGS. 8 through 17  in particular, the apparatus of the present invention is disclosed. Embodiments of an extension arm suitable for mounting a flat-screen electronic peripheral device, such as a computer monitor or television, that is inexpensive and easy to manufacture and assemble, and permits a flat-screen device to be mounted substantially flush with a mounting surface is described in U.S. Provisional Patent Application No. 60/133,378 filed May 10, 1999 entitled “Arm Apparatus For Mounting Electronic Devices”, the disclosure of which is incorporated herein in its entirety. The current invention discloses embodiments that enable the extension arm to substantially hide from view the cables to and from the flat-screen electronic peripheral device within the extension arm. 
     FIG. 8  is an exploded assembly drawing of an extension arm  100  in accordance with one embodiment. The extension arm  100  comprises a first endcap  102 , an upper channel  104 , a lower channel  106 , a second endcap  108 , and a forearm extension  110 .  FIG. 9  illustrates how cables to and from the device are disposed within the lower channel  106 , the second end cap  108 , and the forearm extension  110  of the extension arm  100  so as to be hidden from view.  FIG. 9  will be discussed in more detail later. 
     FIGS. 10C   a  and  10   b  illustrate the first endcap  102 , in accordance with one embodiment of the invention. In the embodiment shown, the first endcap  102  includes a partially-enclosed housing  112  which has flat, oppositely-disposed endwalls  146  and  148  fixedly connected by a sidewall  150 . The sidewall  150  extends partially around the partially-enclosed housing  112  so as to permit manipulation of components to be assembled within the first endcap  102 . In one embodiment, the endwalls  146  and  148  are semi-circular in shape and are connected along a semicircular edge to the sidewall  150 , which extends perpendicularly therebetween. 
     FIG. 10   a  illustrates the first endcap  102  having a shaft  114  disposed on the endwall  148 . The shaft  114  is preferably integrally molded to the endwall  148  of the first endcap  102 . Preferably the entire first endcap  102  (the partially enclosed housing  112  and the shaft  114 ) is molded from zinc. The endwall  146  has a hole  152  disposed therethrough. Within the partially enclosed housing  112  and integrally molded on the sidewall  150  are stops  156  disposed in proximity to the endwalls  146 ,  148 ; trough walls  158  disposed longitudinally along the inner surface of the sidewall  150  between the endwalls  146  and  148  so as to define a trough  160  therebetween; and shelves  162  disposed adjacent to the endwall  148 . 
   The stops  156  serve to stop upward or downward movement of the extension arm  100  when ends of the upper channel  104  and the lower channel  106 , respectively, meet the stops  156  when the extension arm  100  is in extended positions. The trough  160  disposed between the trough walls  158  allows a clevis  120  to be moved therein, as discussed in more detail later.  FIG. 10   b  illustrates the shelves  162  defining co-planar faces separated by a groove  164 . The shelves  162  have a connection means, such as self-tapping screw holes  154  disposed therein. The co-planar faces of the shelves  162  are configured to engage a retainer clip  126 , which is fastened in place by, for example, a pair of screws  128 . When the retainer clip  126  is fastened in place, the groove  164  defines a spacing for accepting one end of a threaded rod  124 , as discussed in more detail below. 
   The threaded rod  124  and the clevis  120  are now fabricated and assembled in the first endcap  102 . The threaded rod  124  is employed within the first endcap  102  so as to adjustably support the clevis  120 .  FIG. 10   c  illustrates the threaded rod  124  having a first end  166  which has a circular cross-section within which is axially disposed a shaped opening  168 , for example a hex-shaped opening, for accepting a shaped key (not shown), such as a hex-shaped key. Advantageously, a cross-sectional diameter of the first end  166  is smaller than a cross-sectional diameter of the hole  152 , so as to be inserted therein. Adjacent the first end  166  is a shoulder  170 . Advantageously, the shoulder  170  has a circular cross-section having a diameter that is larger than the cross-sectional diameter of the hole  152 . Thus, in a preferred embodiment, the shoulder  170  abuts an inner surface of the endwall  146  and retains the first end  166  within the hole  152 . 
   The threaded rod  124  also includes a threaded section  172  which is configured to threadingly engage the clevis  120 . A second end  174  of threaded rod  124  is disposed in the groove  164  located between the shelves  162  of the first endcap  102 . Preferably, the second end  174  of the threaded rod  124  has a circular cross-section having a diameter that is smaller than the size of the groove  164 , such that the second end  174  is supported between the shelves  162  but is free to rotate therein. 
   As previously mentioned, threadedly mounted on the rod  124  is the clevis  120 . The clevis  120  as illustrated in  FIG. 10   d,  has a tapped hole  176  formed therein for receiving the threaded rod  124 . The clevis  120  also has a pair of fastening members  178  at a first end to which are fastened a first end of a gas spring  122 . The second end of the clevis  120  is configured to slidably engage the trough  160 . 
   When the first end  166  of the threaded rod  124  is engaged by a shaped key, the shaped key is employed so as to rotate the threaded rod  124  around its axial centerline. When the threaded rod  124  is rotated around this axis of rotation, the clevis  120  moves along the length of the threaded rod  124  in a direction that corresponds to the direction which the shaped key is turned. This movement of the clevis  120  permits the gas spring  122  to be adjusted. 
   The partially enclosed housing  112  is configured with, for example, holes  116  to receive a connection mechanism, such as pins  118 , therethrough. The shaft  114  is configured to be inserted for pivotable rotation in a support mount (not shown), which may be a wall, desk or pole mount, or a configurable mount as shown and described in Applicant&#39;s copending patent applications: Provisional Patent Application No. 60/106,729 filed on Nov. 2, 1998 and Provisional Patent Application No. 60/108,469 filed on Nov. 14, 1998. 
     FIGS. 11   a-d  illustrate several views of the upper channel  104 , according to one embodiment of the invention. The upper channel  104  includes a U-shaped body  130  having a longitudinal axis  188  and integrally cast rollers  132  disposed at opposite ends of the U-shaped body  130 . The U-shaped body  130  comprises a channel bottom  180  from which extend two channel sidewalls  182 . The channel bottom  180 , the sidewalls  182  and the rollers  132  of the upper channel  104  are preferably integrally cast from zinc, which gives the upper channel  104  a lesser weight, and a degree of structural rigidity, more suitable for lighter-weight flat-screen devices than the prior art upper channel  14  which is stamped from heavy gauge steel. The rollers  132  have a hole  184  therethrough (either cast or subsequently drilled) for receiving a connection mechanism, such as the pins  118 . Additionally, the upper channel  104  comprises a threaded hole  186  configured and sized to receive a threaded end of a ball stud  138 . The threaded hole  186  is also integrally cast. The ball stud  138  is configured and sized to receive a second end of the gas spring  122 . 
   Unlike the prior art upper channel  14  in which the U-shaped channel is formed by heating a piece of steel and bending the steel to form the channel bottom  60  and the sidewalls  62 , the upper channel  104  of the invention is cast molded. The use of cast molding ensures the angle between the channel bottom  180  and the sidewalls  182  is exactly the same each and every time. Moreover, cast molding enables the sidewalls  182  to be tapered. As illustrated in  FIGS. 11   c  and  11   d,  both an outer surface and an inner surface of the sidewalls  182  may taper in, for example, by approximately 1 degree. It should be noted that the taper is not limited to 1 degree, and that the taper of the inner surface and the outer surface need not be the same. The taper provides several advantages including more clearance between the upper and the lower channels  104 ,  106  when the upper and the lower channels  104 ,  106  are brought together during usage. That is, the inner surface of the sidewalls  182  being displaced by 1 degree means that there will be additional clearance for the lower channel  106  to fit therewithin. The additional clearance will help prevent the upper channel  104  and the lower channel  106  from scraping together. 
     FIGS. 12   a-e  illustrate several views of the lower channel  106 , according to one embodiment of the invention. The lower channel  106  includes a U-shaped body  134  having a longitudinal axis  200  and integrally cast rollers  136  disposed at opposite ends of the U-shaped body  134 . The U-shaped body  134  of the lower channel  106  comprises a channel bottom  190  from which extend two channel sidewalls  192 . The channel bottom  190 , the sidewalls  192  and the rollers  136  of the lower channel  106  are preferably integrally cast from zinc, which gives the lower channel  106  a lesser weight when compared to heavy gauge steel, and a degree of structural rigidity, more suitable for lighter-weight flat-screen devices. The rollers  136  have a hole  194  therethrough (either cast or subsequently drilled) for receiving a connection mechanism, such as the pins  118 . 
   The channel bottom  190  additionally includes a cable channel  196  running longitudinally therealong. In the embodiment shown, a first end  197  of the cable channel  196  starts near an end of the channel bottom  190  that pivotably connects to the first endcap  102 . The cable channel  196  then runs along the entire length of the channel bottom  190  to the end of the channel bottom  190  that pivotably connects to the second endcap  108 . Thus, the second end  199  of the cable channel  196  is an opening between the roller  136  at the end of the channel bottom that pivotably connects to the second endcap  108 . The first end  197  may be, for example, rounded to improve the rigidity of the lower channel  106 . The cable channel  196  is configured to receive a cable cover  198  (illustrated in  FIG. 12   e ) which is configured to removably fit within the cable channel  196 . Thus, cables of the mounted device may be substantially retained within the lower channel  106  so as to hide them from view and protect them from harm. The cable channel  196  and the cable cover  198  enable cables to be accessed when desired, while securing them within the lower channel  106 . 
   As illustrated in  FIGS. 12   c  and  12   d  the sidewalls  192  of the lower channel  106  are tapered. For example, an outer surface of the sidewalls  192  may be tapered approximately ½ degree while an inner surface may be tapered approximately 1 degree. It should be noted that the taper is not limited to a particular angle, and that the taper of the inner surface and the outer surface may be the same. The taper is possible because the lower channel  106  is, in the preferred embodiment, cast molded. As noted above with respect to the upper channel  104 , the taper provides more clearance between the upper channel  104  and the lower channel  106  so as to reduce or eliminate the chance of the upper and the lower channels  104 ,  106  scraping. 
   As illustrated in  FIG. 12   e , the cable cover  198  includes a top cover  202  with two sidewalls  204  protruding therefrom. A far end of each sidewall  204  has a catch  206  formed thereon so as to engage with the cable channel  196 . 
   The second endcap  108  includes a partially enclosed housing  250  and a shaft assembly  252 . As illustrated in  FIGS. 13   a-c , the partially enclosed housing  250  has a first endwall  254  and a second endwall  256  oppositely-disposed from each other and fixedly connected by a sidewall  258 . The sidewall  258  extends partially around the partially-enclosed housing  250  so as to permit manipulation of components, such as cables, which may be contained therewithin. The first endwall  254  has a hole  260  disposed therethrough and threaded holes  262  disposed therein that are in communication with the hole  260 . Disposed with the threaded holes  262  are set screws  264 . Preferably, the diameter of the hole  260  is large enough to allow a plug end of a cable to fit therethrough. 
   As illustrated in  FIGS. 14   a-c , the shaft assembly  252  preferably includes two symmetrical endcap adapters  266  which when assembled provide a hollow shaft  268 . The endcap adapters  266  have a mounting end  270  and a shaft end  272  that is thinner than the mounting end  270 . As illustrated in  FIG. 15 , the mounting end  270  of both of the endcap adapters  266  are inserted into the hole  260  and are coupled together and to the partially enclosed housing  250 , to form the second endcap  108 , by tightening the set screws  264 . 
   The upper and the lower channels  104 ,  106  and the first and the second endcaps  102 ,  108  are configured so as to form an adjustable parallelogram. When configured, the shaft  114  of the first endcap  102  and the hollow shaft  268  of the second endcap  108  point in opposite directions. For example, as illustrated in  FIG. 8 , the shaft  114  of the first endcap  102  extends vertically downward while the hollow shaft  268  of the second endcap  108  extends vertically upward. The shape of the parallelogram is retained by the gas spring  122 . As previously mentioned, the first end of the gas spring  122  is attached to the ball stud  138  mounted within the upper channel  104  and the second end is adjustably mounted to the clevis  120  within the first endcap  102 . Generally, the gas spring  122  is sized so as to have a fixed length until an upward or downward force is exerted at the second endcap  108  that exceeds the gas spring&#39;s designed resistance. Thus, the gas spring  122  retains the parallelogram shape when the only force exerted at the second endcap  108  is the weight of the flat-screen device. However, the gas spring  122  permits the parallelogram shape to be adjusted when a user pushes the flat-screen device coupled to the forearm extension  110  up or down. 
   With reference to  FIGS. 16   a  and  16   b , the forearm extension  110  includes a body  140  having a first female coupling  142  located on a first end and a second female coupling  144  located on a second end. The first female coupling  142  has an inner diameter  209  that is sized to rotatably engage the hollow shaft  268  of the second endcap  108 . The first female coupling  142  is also configured to receive a cable through the hollow shaft  268 . That is, the first female coupling  142  has a cable slot  274  formed therein, for example by milling the cable slot  274  into the first female coupling  142 , or by casting the first female coupling  142  with the cable slot  274  integrally formed therein. 
   The first female coupling  142  preferably has a set screw  212  formed within a wall  214  thereof. The set screw  212  can be tightened to prevent the first female coupling  142  from rotating about the hollow shaft  268 . Advantageously, the first female coupling  142  has a plurality of voids  217  formed in the wall  214 , which saves on material costs and permits the forearm extension  110 , when cast, to be cooled more quickly. The quicker cooling enables the production quantity to be increased. 
   A bushing  210  ( FIG. 8 ) is preferably used to engage the first female coupling  142  and the hollow shaft  268 . That is, the bushing  210  is placed over the hollow shaft  268  and within the first female coupling  142 . The bushing  210  is preferably made of a smooth material, such as plastic, in order to reduce friction and prevent metal to metal contact. As illustrated in  FIGS. 17   a  and  17   b , the bushing  210  also has a cable slot  276  formed therein. The cable slots  274 ,  276  are aligned so that a cable can pass therethrough. When the set screw  212  is tightened it causes the bushing  210  to flex inward and frictionally engage the hollow shaft  268  and thus prevent the forearm extension  110  from rotating about the hollow shaft  268 . The hollow shaft  268  and the first female coupling  142  are held together by utilizing a screw  211  and a washer  213  (FIG.  8 ). 
   The body  140  preferably has an inverted U-shape with a topwall  207  and two sidewalls  208  so that a cable can be hidden therein. Advantageously attached within the U-shaped body  140 , and preferably on the topwall  207 , is a cable holder  278  (FIG.  8 ). The cable holder  278  secures a cable within the U-shaped body so that it can be hidden from view as it travels the length of the forearm extension  110 . 
   The second female coupling  144  is for attachment to a device mounting (not shown), such as a tilter (described in Applicant&#39;s co-pending Provisional Patent Application No. 60/137,088 filed on Jun. 2, 1999), a platform, or other means for supporting a flat-screen device. Thus, the second female coupling  144  has an inner diameter  218  that is sized to rotatably engage a shaft of the device mount. A bushing  220  (FIG.  8 ), preferably made of a smooth material such as plastic, is placed over the shaft and within the second female coupling  144 . The second female coupling  144  preferably has a set screw  222  formed within a wall  224  of the second female coupling  144 . When the set screw  222  is tightened it causes the bushing  220  to flex inward and frictionally engage the shaft and thus prevent the device mount from rotating around the second female coupling  144 . Advantageously, the second female coupling  144  also has a plurality of voids  226  formed in the wall  224 . 
   The embodiment of the forearm extension  110  illustrated in  FIGS. 16   a  and  16   b , has the topwall  207  flush with an upper edge of the female couplings  142 ,  144 . Since the first female coupling  142  is larger than the second female coupling, the center of the first female coupling  142  is not aligned with the center of the second female coupling  144  or an axial centerline  228  of the body  140 . It should be noted that an alternative embodiment as shown in  FIG. 18  is to have the center of the female couplings  142 ,  144  and the axial centerline  228  of the body  140  all aligned, so that the topwall  207  would not be aligned with an upper edge of the first female coupling  142 . 
   The embodiment illustrated in  FIG. 16   a , has the body  140  horizontally disposed between the female couplings  142 ,  144  when the axial centerlines of the female couplings  142 ,  144  are vertically disposed. It should be noted however that the body  140  is not limited to be horizontally disposed and may be disposed at an incline in this embodiment as shown in FIG.  19 . 
   The present invention permits a flat-screen device which is mounted to a wall to be flattened against the wall while hiding the extension arm  100  within the shadow of the device. That is, the forearm extension  110  may be folded into a position which is directly above the upper and the lower channels  104 ,  106 . As a result, the mounted device is flush to the mounting surface and substantially hides the parallelogram, formed by the first and the second endcaps  102 ,  108  and the upper and the lower channels  104 ,  106 , as well as the forearm extension  110  from view. Thus, the aesthetic appeal of the extension arm  100  is increased and the space occupied by the extension arm  100  and the device is minimized. 
   Referring back to  FIG. 9 , a flat screen monitor  300  is attached to a tilter  302  which is rotatably coupled to the second female coupling  144 . A cable  304 , such as a power cable, proceeds from the monitor  300  to the underside off the U-shaped body  140  of the forearm extension  110 . The cable  304  is held in place within the U-shaped body  140  by the cable holder  278 . The cable  304  proceeds from the body through the cable slots  274 ,  276  in the bushing  210  and the first female coupling  142 . The cable then proceeds through the hollow shaft  268  of the second endcap  108 . The cable exits the second endcap  208  through the open end of the partially enclosed housing  260 . The cable proceeds down the length of the lower channel  106  and exits at the first end  197  of the cable channel  196 . 
   Preferably, the cable  304  is inserted into the extension arm  100  as portions of the extension arm  100  are being assembled. That is, the cable  304  is placed under the U-shaped body  140  of the forearm extension  110  and is held in place by the cable holder  278 . The cable is then passed through the cable slots  274 ,  276 . The cable  304  including the plug  306  is then fed through the hole  260  in the second endcap  108 . The second endcap  108  is now assembled by inserting the mounting end  270  of each endcap adapter  268  into the hole  260 , thus surrounding the cable  304 . The endcap adapters  268  are held together and within the hole  260  by tightening the set screws  264 . The hollow shaft  268  is then placed within the first female coupling  142 . The cable  304  is placed within the lower channel  106 , prior to the lower channel  106  and the second endcap being secured together. This ensures that the cable  304  is above the roller  136  and is contained within the hollow bar formed by the upper channel  104  and the lower channel  106 . 
   Referring back to  FIG. 8 , several additional components of the extension arm  100  are discussed. For aesthetic purposes, a bumper  280  may be placed on the second endwall  256  of the second endcap  108  and a plug  282  may be placed over the first female coupling  142 . A washer  284  may be placed over the two endcap adapters  268  to help secure them together. 
   Although this invention has been illustrated by reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made that clearly fall within the scope of the invention. The invention is intended to be protected broadly within the spirit and scope of the appended claims.