Abstract:
A display arm having an elongated outer housing, an elongated inner housing telescopically engaged within the outer housing, a biasing member coupled with the outer housing and operative to counter-balance the inner housing within the outer housing, and a locking mechanism for locking the position of the inner housing relative to the outer housing. The locking mechanism may include a first locking vane and a second locking vane, each locking vane having a sloped surface abutting an edge of the inner housing and a second surface abutting an interior surface of the outer housing, wherein the sloped surfaces initiate spreading of the locking vanes when the locking vanes are pulled into an extended position by the locking mechanism such that the second surfaces engage the interior surface of the outer housing with sufficient force to prevent movement of the inner housing relative to the outer housing.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This application claims the benefit of the filing date of U.S. Provisional Patent Application Ser. No. 60/487,999 filed Jul. 17, 2003, the disclosure of which is hereby incorporated herein by reference as if fully set forth herein. 

   BACKGROUND OF THE INVENTION 
   The present invention relates in general to the field of display arms, and more particularly, to adjustable display arms for devices such as electronic components including computer monitors, keyboards, televisions, and the like. 
   There are many different devices relating to display arms for electronic components, such as those related to computers. Many times, these devices are employed in order to conserve space. Rather than placing such components directly on a desk, table, or other supporting surface, display arms are used to keep the components elevated from the surface. These display arms are generally attached to the surface or an adjacent surface and may be fixed in one or more positions by anchors or the like. These devices can save desktop space, but still render an otherwise vacant area occupied with the electronic components, as well as the display arm. 
   In many instances, there is not a surface but rather a wide-open area for which to conserve space, or in which to use a display arm. For example, a generally unemployed area within a given space is that above head-level. Storage devices that utilize this area allow for components to be stored out of the way to conserve floor space or other space, which can be populated by other materials. Televisions that utilize a remote control are perfect examples of something that can be stored in this fashion. Sporadically used computer components are another. U.S. Pat. No. 5,127,617 to Bergetz teaches a swivel mounting device for televisions and the like. This device allows for a television to be supported from the ceiling, but does not allow for the television to be adjusted in the vertical direction. While this will still allow for the use of a television through a remote control, computer components and other hands-on devices are not appropriate for use with this device. 
   U.S. Pat. No. 5,797,568 to Canton Gongora et al. and U.S. Pat. No. 4,964,606 to Beam et al. allow for vertical adjustment in a monitor-supporting device. However, this adjustment can only be achieved in fixed increments. In order to perform the vertical adjustment as taught in these patents, the weight of the components must constantly be supported, an anchoring device must be removed, the components must be raised or lowered into position, and the anchoring device must be replaced. Depending on the weight of the component and the height above the surface, this procedure may require two or more persons and is often quite difficult and time consuming. 
   The present invention is directed to a display arm that may be raised and lowered with minimal exertion while supporting an electronic component. The display arm of the present invention allows computer components and the like, that may be used intermittently, to be stored at an elevated level while being easily adapted to be moved to a lower level for ease of use or viewing. Relocation from an upper level to a lower level, and vice-versa, may be achieved quickly and efficiently with minimal effort. Relocation may also be achieved through an infinite range of adjustment intervals, rather than at preset fixed intervals. 
   SUMMARY OF THE INVENTION 
   In accordance with one aspect of the present invention, an adjustable display arm for positioning a device in a plurality of positions is disclosed. The display arm may comprise an elongated outer housing, an elongated inner housing telescopically engaged within the outer housing, a biasing member coupled with the outer housing and operative to counter-balance the inner housing within the outer housing, and a locking mechanism for locking the position of the inner housing relative to the outer housing. 
   The locking mechanism may comprise a first locking vane and a second locking vane, each locking vane having a sloped surface abutting an edge of the inner housing and a second surface abutting an interior surface of the outer housing, wherein the sloped surfaces may initiate spreading of the locking vanes when the locking vanes are pulled into an extended position by the locking mechanism such that the second surfaces engage the interior surface of the outer housing with sufficient force to prevent movement of the inner housing relative to the outer housing. 
   The locking vanes may further comprise overlapping apertures and the display arm may further comprise a locking rod extending through the overlapping apertures at a first end while being engaged with the locking mechanism at a second end to actuate the locking vanes upon manipulation of the locking mechanism. 
   The display arm may be adapted to be mounted in a vertical orientation such that the outer housing includes a vertically oriented longitudinal axis. 
   The inner housing may be adjusted relative to the outer housing in an infinite number of positions between a greatest length, when the inner housing is extended a maximum distance from within the outer housing, and a minimum length, when the inner housing is extended a minimum distance from within the outer housing. 
   The locking mechanism may further comprise a locking handle adapted to pull the locking vanes into the extended position upon actuation of the locking handle about a locking handle pivot point into a first position. 
   The locking mechanism may further comprise a locking handle adapted to push the locking vanes from the extended position upon actuation of the locking handle about the locking handle pivot point into a second position. 
   The locking mechanism may further comprise a locking rod linking the locking handle to the locking vanes from a locking rod connection point on the locking handle to overlapping apertures provided through the locking vanes and a spring connection rod linking the locking handle to the spring from a spring rod connection point on the locking handle to the spring. 
   The locking rod connection point and the spring rod connection point of the locking handle may be arranged such that the locking rod connection point and the spring connection point revolve about the locking handle pivot point. 
   The revolving of the locking rod connection point and the spring rod connection point of the locking handle about the locking handle pivot point may be permitted through a range of approximately 90°. 
   The outer housing and the inner housing may be spaced apart from one another by a fixed bushing and a sliding bushing. 
   The outer housing and the inner housing may be cylindrical. 
   The adjustable display arm may further comprise a mounting mechanism attached to the outer housing for mounting the adjustable display arm to a fixed object. 
   The adjustable display arm may further comprise an attachment block extending from the inner housing for attaching the device to be displayed to the adjustable display arm. 
   The biasing member may be a constant force spring. 
   The constant force spring may have a spring force of sufficient magnitude to support the inner housing and the device to be displayed. 
   In accordance other aspects of the present invention, an adjustable display arm for positioning a device in a plurality of vertical positions may comprise an elongated outer housing, an elongated inner housing having portions telescopically engaged within the outer housing, a biasing spring coupled with the outer housing for supporting the inner housing within the outer housing, and a locking mechanism for locking the position of the inner housing relative to the outer housing, the locking mechanism comprising a lever rotatably engaged to the outer housing and a pair of locking vanes within the outer housing, wherein actuation of the lever forces the locking vanes against an inner surface of the outer housing inhibiting movement of the inner housing relative to the outer housing by frictional forces between the locking vanes and the inner surface of the outer housing. 
   The inner housing may be locked relative to the outer housing in any of an infinite number of positions. 
   In accordance with further aspects of the present invention, an adjustable display arm for positioning a device in a plurality of positions may comprise an elongated outer housing, an elongated inner housing telescopically engaged within the outer housing, a biasing member coupled with the outer housing and operative to counter-balance the inner housing within the outer housing, and means for locking the position of the inner housing relative to the outer housing. 
   In accordance with still further aspects of the present invention, a method of positioning a display device utilizing an adjustable display arm having an inner housing telescopically engaged within an outer housing, wherein the inner housing may be locked relative to the outer housing by manipulation of a locking mechanism between a first position and a second position to apply friction between a pair of locking vanes associated with the inner housing and the outer housing, may comprise adjusting the position of the inner housing relative to the outer housing and locking the inner housing relative to the outer housing my moving a locking mechanism from a first position to a second position to apply friction between a pair of locking vanes associated with the inner housing and the outer housing. 
   The method of positioning a display device may further comprise the step of returning the locking mechanism to the first position to remove friction between the pair of locking vanes associated with the inner housing and the outer housing. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above description, as well as further objects, features and advantages of the present invention will be more fully understood with reference to the following detailed description of an adjustable display arm for electronic components, when taken in conjunction with the accompanying drawings. 
       FIG. 1  depicts a cross-sectional view of the display arm of the present invention; 
       FIGS. 2   a  and  2   b  depict exploded plan views of the locking vanes forming a part of the invention; 
       FIGS. 3   a  and  3   b  depict two cross-sectional views of a portion of the display arm of  FIG. 1 , showing the operation of the locking vanes; and, 
       FIGS. 4   a  and  4   b  depict the cross-sectional views of the display arm depicted in  FIGS. 3   a  and  3 B, with one locking vane highlighted for clarification. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   In describing the preferred embodiments of the subject matter illustrated and to be described with respect to the drawings, specific terminology will be resorted to for the sake of clarity. However, the invention is not intended to be limited to the specific terms so selected and is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar purpose. 
   The display arm of the present invention is well suited for supporting devices, particularly electronic components such as CRT screens, LCD screens, or plasma displays, keyboards or television sets. The display arm is ideal for mounting at an elevated location so the supported device will not interfere with an below, such as a work area or an area where individuals may congregate. Once so supported, the display arm may be extended downward so the device may be accessed for hands-on operation or for easy viewing. 
   Notwithstanding the natural use with electronic components, the present invention is not intended to be so limited. Rather, any suitably sized device for which there is a need for a versatile and adjustable mounting system may be utilized in conjunction with the present invention. As will be discussed in greater detail, the invention incorporates elements capable of being modified or exchanged for use with mounted objects of varying sizes, configurations and weights, as the need arises. 
   The display arm of the present invention is generally constructed to be extendable in a telescopic manner to provide variable height adjustment for a supported device. The supported device may therefore be positioned vertically at different elevations, depending upon the needs of the particular user or users. This ability to position the supported device at different elevations is based upon the telescopic nature of the display arm, in general, and upon the inner housing being freely adjustable within the outer housing in particular. 
   With reference to  FIG. 1 , a cross-sectional view of the preferred embodiment of the present invention, the display arm  100  generally comprises an outer housing  102  with an inner housing  104  slideably engaged therein. The outer housing  102  is preferably offset from the inner housing  104  by both a fixed bushing  106  and a sliding bushing  108 , leaving a voided area  107  therebetween. Sliding of the inner housing  104  relative to the outer housing  102  therefore alters the display height of a device  101  attached to the inner housing by attachment blocks  110 . Once slid into the preferred position, the inner housing  104  may be temporarily locked by actuation of locking vanes  112  via locking handle  114  and its associated locking system  140 . To assist with adjustment of the device  101  height, the weight of the inner housing  104  and the device may be biased by a constant force spring  116  mounted to the outer housing  102  and connected to elements of the inner housing  104  to provide an uplifting force on the inner housing. 
   This counter-balancing spring  116  is preferably in the nature of a Negator spring which is well known in the art and available from a number of commercial sources. The Negator spring  116  is generally a coiled flat spring supported about a shaft  119  as shown in  FIG. 1 . The size and counterbalancing effect of the spring  116  may be varied depending upon the nature of the display arm  100  and the weight of the device  101  to be supported. The particular selection and technical requirements for the spring  116  are known to those skilled in the art. It will be appreciated that any number of Negator springs  116  may be utilized for counterbalancing the weight of the telescoping components of the display arm  100  and supported device  101 . For example, in accordance with other embodiments of the present invention, two or more Negator springs may be utilized in conjunction with a single display arm  100 . 
   Outer housing  102  is preferably an elongated cylindrical body having a first end  118  and a second end  120 . Each of the two ends  118 ,  120  are opposed along the longitudinal axis  103  of the outer housing  102 . Preferably mounted at the first end  118  is a support flange  122 . The support flange  122  may act as a base upon which the constant force spring  116  may be mounted. A cover  124  may be provided to protect the spring  116  and to improve the aesthetics of the display arm  100 . 
   An end portion  126  of the spring  116  may be permitted to pass through an aperture  128  provided in the support flange  122 . The aperture  128  opens from within the spring cover  124 , if so provided, into an interior section  130  of outer housing  102 . Extending through the aperture  128 , the end portion of the spring  126  may attach to a spring connecting rod  144 , as will be discussed in greater detail below. 
   As with outer housing  102 , inner housing  104  is also preferably cylindrical in shape, and is preferably of a smaller diameter than outer housing  102  so it may fit therein in a telescopic arrangement. Inner housing  104  may comprise a first end  132  slidingly engaged within outer housing  102 , and a second end  134  extending from within the outer housing at the second end  120  of the outer housing. As previously discussed, inner housing  104  may be offset from outer housing  102  by a fixed bushing  106  mounted at the second end  120  of outer housing  102  and a sliding bushing  108  mounted at the first end  118  of the outer housing. It will be appreciated that the fixed bushing  106  may be permanently affixed to the outer housing  102  while the sliding bushing  108  is preferably attached to the inner housing  104 . The attachment of the bushings  106 ,  108  to the respective housings  102 ,  104  may be through chemical means such as adhesives, or through mechanical means such as riveting. The sliding bushing  108  preferably slides along the interior surface  131  of the outer housing  102  into the voided area  107  between the two housings upon movement of the inner housing  104  relative to the outer housing. It will be appreciated that when the first end  132  of the inner housing is closest to the first end  118  of the outer housing  102 , the voided area  107  is greatest. Conversely, when the first end  132  of the inner housing is closest to the second end  120  of the outer housing  102 , the voided area is minimized, and may be completely consumed by the sliding bushing  108  and the fixed bushing  106 . 
   Attached to the exterior surface  136  of the interior housing  104  are preferably a pair of display and accessory attachment blocks  110 . The blocks  110  are typically mechanically attached to the outer housing  102 , such as through the use of rivets, bolts, or welds. The blocks may also be chemically bonded, for example with adhesives. The blocks  110  provide attachment points for connecting and displaying the device  101 . Blocks  110  of this type are generally well known in the art, and may range from simple brackets to more intricate castings custom made for each individual application. As the blocks  110  are preferably fixed to the inner housing  104 , it will be apparent that the position of the blocks  110  is dependent on the position of the inner housing relative to the outer housing  102 . 
   The outer housing  102  may also include an attachment mechanism  111  for attaching the display arm  100  to a fixed support, such as a wall or ceiling. Typically, the attachment mechanism  111  is mechanically attached to the outer housing  102 . The mechanism may be a universal-type mount, or may be custom manufactured for the specific application. In any event, this attachment mechanism  111  is preferably designed to support the weight of the display arm  100  as well as the intended component  101  to be displayed, with an appropriate safety factor built in. It will be appreciated that the design criteria may incorporate live loads as well as dead loads, due to the movement capabilities of the display arm  100  particularly with respect to the inner housing  104  relative to the outer housing  102 . Suitable attachment mechanisms  111  are well known in the industry. 
   Attached to the second end  134  of the inner housing  104  may be a locking handle  114 . This handle  114  may be utilized to selectively restrict or permit sliding of the inner housing  104  relative to the outer housing  102  by utilizing frictional forces generated between the locking vanes  112  and the inner surface  131  of outer housing  102  when the locking handle  114  is operated. The locking handle  114  forms a portion of a locking system  140  working in concert with the counterbalancing effects of the constant force spring  116 . In addition to the locking handle  114 , the locking system may include a locking rod  142  and the locking vanes  112 . Generally, the locking system  140  is utilized to selectively restrict or permit sliding of the inner housing  104  relative to the outer housing  102  by utilizing frictional forces generated between the locking vanes  112  and the inner surface  131  of outer housing  102  when the locking handle  114  is operated. 
   The locking handle  114  preferably comprises a grasping portion  148  at its proximal end  152  and a connecting plate  156  at its distal end  150 . The grasping portion  148  is intended to be a comfortable area for the user to grasp, such as a shaped handle. Between the grasping portion  148  and the connecting plate  156  is preferably an elongated lever portion  154 , the length of which helps to determine the amount of leverage available on the system for a given force applied to the grasping portion  148 . 
   The second end  134  of the inner housing  104  may include a support plate  151  mounted along the longitudinal axis  103  of the outer housing  102  and parallel to the length of the locking handle  114 . The connecting plate  156  is preferably attached to the support plate  151  by a handle pivot pin  146 . The entire handle assembly  114 , including the grasping portion  148 , the lever portion  154  and the connecting plate  156  may rotate about pin  146  when the lever portion is operated. 
   A rod pin  158  may connect the connecting plate  156  to both the locking rod  142  and the spring connecting rod  144 , at a single attachment point. The two pins  146 ,  158  may be mounted in an over-the-center-type arrangement, such that the rod pin  158  may revolve about the handle pivot pin  146  in a circular path such that the relative distance between the rod pin and the handle pivot pin remains constant. As viewed in accordance with the cross-section shown in  FIG. 1 , it will therefore be appreciated that the relative distance of the rod pin  158  from the outer housing  102 . Preferably, such revolution is only permitted through a range of approximately 90°. Of note, this arrangement permits the permits the handle assembly  114  to provide tension on the locking rod  142  and connecting rod  144  to selectively pull the locking vanes  112  toward the locking system  140  when the handle  114  is lowered and compression to push the locking vanes  112  away from the locking system when the handle is raised. 
   As stated, both the spring connecting rod  144  and the locking rod  142  are connected to the rod pin  158  at the second end  134  of the inner housing  104 . The spring connecting rod  144  is also attached to the constant force spring  116  near the first end  132  of the inner housing  104  at the spring connecting rod&#39;s opposite end. This connection helps to support the displayed device  101  by virtue of the spring  116  pulling the inner housing  104  upward. The constant force spring  116  may be sized to have a length and spring rate appropriate for the specified length of travel of the inner housing  104  and the weight of the inner housing and the displayed device  101 . It will be appreciated that the spring rate is preferably sufficient to assist with the raising of the displayed object  101 , without being so strong as to raise the object on its own or too weak to provide any real assistance. Ideally, the spring  116  is sized such that the weight of the displayed object  101  will be perfectly balanced against the force of the spring, such that the displayed object will generally remain in a given position absent the influence of any external forces. As previously addressed, multiple springs  116  may be provided such that their combined forces may act together. 
   In addition to being attached to the rod pin  158 , the locking rod may also be attached to the locking vanes  112 , at its opposite end. The locking vanes  112   a ,  112   b , are shown more clearly in the exploded views shown in  FIGS. 2   a  and  2   b . Each of the locking vanes  112   a ,  112   b  comprises a first section  160   a ,  160   b  and a second section  162   a ,  162   b . The first section  160   a ,  160   b  of each locking vane  112   a ,  112   b  may be mounted in proximity to the interior surface  131  of the outer housing  102  near the first end  118 . Each includes a bearing surface  164   a ,  164   b  which bears against the interior surface  131  of the outer housing  102  when the inner housing  104  is locked in position. The second section of each locking vane  162   a ,  162   b  extends toward the second end  134  of the inner housing  104  and includes an angled bearing surface  166   a ,  166   b  which may bear against the edge  135  of the inner housing  104  at its second end  134 . Each of the locking vanes  112   a ,  112   b  also preferably includes an aperture  168   a ,  168   b  within the second section  162   a ,  162   b.    
     FIGS. 3   a  and  3   b  detail the method of locking the locking vanes  112 .  FIG. 3   a  depicts the locking vanes  112  in the unlocked position. As is shown and previously discussed, inner housing  104  is mounted within outer housing  102  with sliding bushing  108  and fixed bushing  106  therebetween. The locking vanes  112  are positioned within the housings  102 ,  104  and overlie each other such that their respective apertures  168   a ,  168   b  align, and their bearing surfaces  164   a ,  164   b  face away from each other toward the interior surface  131  of the outer housing  102 . Locking rod  142  preferably extends through the apertures  168   a ,  168   b  to connect the locking system  140  ( FIG. 1 ) to the locking vanes  112 . When the locking handle  114  ( FIG. 1 ) is in the unlocked position, the locking rod  142  will preferably raise to push the locking vanes  112   a ,  112   b  toward the first end  118  of the outer housing. As shown in  FIG. 3   a , in this position the bearing surfaces  164   a ,  164   b  are either not in contact with the interior surface  131  outer housing  102 , or just slightly in contact. Either way, there is little or no friction between the bearing surfaces  164   a ,  164   b  and the interior surface  131  of the outer housing  102 , such that the inner housing  104  is free to slide within the outer housing. 
   Meanwhile, as shown in  FIG. 3   b , when the locking rod  142  is lowered such as when the locking handle  114  ( FIG. 1 ) is moved downward toward the locked position, the locking vanes  112  will be pulled by the locking rod. This downward movement causes each angled bearing surface  166   a ,  166   b  to contact the edge  135  at the extreme first end  132  of the inner housing  104 . Because of the incline of the angled bearing surfaces  166   a ,  166   b , the first sections  160   a ,  160   b  of the locking vanes  112   a ,  112   b  are pushed outward toward the outer housing  102 . The further the handle  114  is moved downward of the locking vanes  112   a ,  112   b , the further the first portions  160   a ,  160   b  are pushed outward. Eventually, the bearing surfaces  164   a ,  164   b  will contact the interior surface  131  of the outer housing  102  and develop enough friction to prevent the inside housing  104  from sliding further within the outer housing  102 . At this point, the displayed object is locked into position as releasing the handle  114  will not effect any movement of the inner housing  104  relative to the outer housing  102 . It will be appreciated that because of this novel locking system, the displayed object may be positioned at any height between the highest and lowest position of the display arm, and not merely at fixed predetermined intervals. 
   In this regard, lack of movement downward is self-evident, the bearing surfaces  164   a ,  164   b  cause sufficient friction to prevent such movement. Movement of the inner housing  104  relative to the outer housing  102  in the upward direction is preferably not a concern as the spring rate of the constant force spring  116  is preferably not great enough to overcome the weight of the display device  101  and the inner housing  104 , and the friction of the bearing surfaces  164   a ,  164   b.    
   To better appreciate the operation of the locking vanes  112   a    112   b ,  FIGS. 4   a  and  4   b  are provided.  FIGS. 4   a  and  4   b  each depict locking vane  112   a  shaded or otherwise highlighted for clarification. Locking vane  112   b  remains unshaded and is positioned behind locking vane  112   a . As shown in the figures and previously discussed in greater detail, downward movement of the locking vanes  112   a ,  112   b  causes the bearing surfaces  164   a ,  164   b  to increasingly bear with greater force against the inner surface  131  of outside housing  102 , such as when the locking vanes are moved downward from the position shown in  FIG. 4   a  to that shown in  FIG. 4   b.    
   Although many different materials may be used to construct the adjustable display arm  100  described herein, certain materials have been found to be preferable. For example, aluminum is preferable for both the inner and outer housings  102 ,  104 . Aluminum is preferable for many reasons, including its high strength to weight ratio, excellent finished properties, and low cost. The locking vanes  112  are most advantageously formed from steel. Steel has the benefit of being highly durable and cost effective, without imparting too much of a weight penalty. The bushings  106 ,  108  are preferably formed from plastics or other low friction materials. Other materials which may be used in the manufacture of the display arm, for any of the components, include other metals such as brass or stainless steel, or various plastics. 
   Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims.