Abstract:
A versatile and ergonomic utility cart is provided. The utility cart can be constructed to various heights, depending upon the length of support posts secured between a top and bottom shelf. The cart can be any shape or design: triangular; rectangular; octagonal and so forth. A vertically adjustable tray support arm mounts a support tray in close proximity to the utility cart. The tray support arm includes a vertical member which is inserted through the top shelf and into the support post and is frictionally secured thereto by a spring-loaded wedge assembly. An articulated arm is rotatably mounted to the vertical member at one end and rotatably mounted to a support tray at an opposite end. The interior of the utility cart between the top and bottom shelves may be left exposed and accessible or may be enclosed by a plurality of panels and door assembles.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Technical Field  
           [0002]    The present invention is directed to a utility cart, and more particularly, to an ergonomic utility cart having interchangeable and adjustable tray support assemblies.  
           [0003]    2. Background of the Invention  
           [0004]    The use of utility carts for supporting various office supplies, such as computer equipment, electronic equipment such as overhead projectors for preparing and presenting presentations, and filing cabinets for file folders and the like are well known in the art. These carts are readily transportable, such as being supported by casters, in order to easily move the carts from location to location and room to room thereby enhancing their versatility. Generally the carts come in various sizes for accommodating these different types of equipment and office supplies. As a general rule these carts are of different overall designs in order to accommodate these various needs.  
           [0005]    Another reason why utility carts come in different sizes is to accommodate the different types of computer equipment, either standard central processing unit machines (CPUs) or as a support platform for a laptop computer. The carts can either be used by a person in a standing or seated position according to the desires of the user of the equipment. CPUs themselves can be configured in either a flat condition or a tower condition. Preferably the CPU is hidden such as being on a shelf within an enclosed cabinet and the cart provides for wire management between the keyboard, a pointing device such as a mouse, and the monitor for connecting the particular equipment to the CPU. When configured in a tower arrangement more clearance is required within the cart in order to accommodate the increased height of the CPU. Alternatively a cart having a support platform for a laptop computer is desired, wherein the laptop may be connected to a video presentation device such that the person operating the laptop projects the screen images from the presentation software running on the laptop onto a viewing screen for the personnel to whom the presentation is being giving. Thus sufficient area for supporting a laptop is needed with the cart so that it and the other electronic equipment can be supported by the cart.  
           [0006]    When used as a means for hanging file folders for example, wherein the cart is typically a rectangular four sided apparatus, one or more sides of the cart are left open for access to the files or equipment stored on a lower shelf thereof. In an alternative arrangement a hinged door is provided on one or more sides of the utility cart for gaining access to the interior.  
           [0007]    In those situations where a separate platform is associated with the utility cart, such as for supporting a keyboard or a laptop computer, it is desired that the platform be adjustable both in height and with respect to the orientation it has with the cart. The height accommodates different users of the computer equipment in order to provide an ergonomic work platform for the user in either a seated or standing position. Also it is desired that the platform be positionable with respect to the cart in order to accommodate any type of arrangement that a user may desire.  
           [0008]    It is desirable therefore to provide a utility cart having relatively standardized components which can be configured for various uses, for example a storage cart, computer work station, presentation cart, or a file folder cart, etc.  
           [0009]    It is therefore an object of the present invention to provide a utility cart that is readily reconfigurable by a user according to its intended use.  
           [0010]    It is a further object of the present invention to provide an ergonomic utility cart which can be constructed of standardized components and is readily adjustable according to the needs of the user.  
           [0011]    It is a still further object of the present invention to provide a utility cart which can be provided with any type of exterior finished design.  
           [0012]    It is a still yet further object of the present invention to provide a utility cart having a means of attaching a support tray thereto, which tray can be positioned about the utility cart in a variety of ways.  
         SUMMARY OF THE INVENTION  
         [0013]    In accordance with the above, a cart assembly comprises a bottom shelf and a top shelf having a plurality of support posts secured therebetween. A tray support assembly comprises at least one support arm having a first portion adapted to be frictionally engaged with an interior surface of at least one of the support posts. An articulated arm has a first end connected to a second portion of the support arm opposite the first portion and a support tray connected to a second end of the articulated arm opposite the first end. The support tray is rotatable with respect to the utility cart, whereas the support arm is vertically adjustable within the support post. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    Various other objects, features and advantages of the invention will be readily apparent according to the following description exemplified by the drawings, which are shown by way of example only, wherein:  
         [0015]    [0015]FIG. 1, consisting of FIGS. 1A, 1B and  1 C, are schematic representations of three different heights for various embodiments of the utility cart of the present invention;  
         [0016]    [0016]FIG. 2 is an exploded view of the utility cart shown in FIG. 1C.  
         [0017]    [0017]FIG. 3, consisting of FIGS. 3A and 3B, are cross-sectional views of a corner support post according to the present invention, showing a cart having a door (FIG. 3A) and a solid panel cover (FIG. 3B), respectively;  
         [0018]    [0018]FIG. 4 is an exploded view of a tray support arm according to the first embodiment of the present invention;  
         [0019]    [0019]FIG. 5 is an exploded view of a tray support arm according to a second embodiment of the present invention;  
         [0020]    [0020]FIG. 6 is a detailed view of an upper portion of a vertical member of the tray support arm;  
         [0021]    [0021]FIG. 7, consisting of FIGS. 7A and 7B, are views of a vertical adjustment mechanism of the tray support arms shown in FIGS. 4 and 5 in the released and engaged position, respectively;  
         [0022]    [0022]FIG. 8 is a side view of the tray support shown in FIG. 4 attached to the utility cart of the present invention;  
         [0023]    [0023]FIG. 9 is a side view of the tray support shown in FIG. 5 attached to the utility cart of the present invention; and  
         [0024]    [0024]FIG. 10 is an exploded view of a door assembly for the utility cart of the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0025]    Referring now to the drawings in detail, the various embodiments of the present invention will be described, in conjunction with the Figures, wherein like numerals refer to similar components throughout. As shown in FIG. 1 the utility cart  20  of the present invention is shown as including three different designs: FIG. 1A showing a low cart  20   a , FIG. 1B showing a medium cart  20   b , and FIG. 1C showing a large cart  20   c . In order to describe the utility cart  20  in particular detail and not to limit any of its various uses, the present invention will be generally described so that the low cart  20   a  is used for supporting a standard personal computer, the medium cart  20   b  is used to support a laptop computer for a video presentation and the larger cart  20   c  is used as supporting file folders or binders. Although three separate sizes of the utility cart  20  are shown in drawings, it will be readily appreciated by those skilled in the art that higher or lower carts may also be used, such as useable for a bookshelf, and/or wider carts maybe used. Also, the uses for the cart are interchangeable. For example the rectangular dimension of the carts shown in FIG. 1 could be replaced by either a square design or an oval shaped design. In each of the embodiments shown in FIG. 1 the utility cart  20  is supported on the floor by casters  23 , which enable the cart to be rolled from room to room more easily. Preferably the casters include a lock  26  such that when the cart  20  has been moved to the desired location the casters  23  are locked and thus the cart  20  is prevented from rolling.  
         [0026]    As shown in the exploded view of FIG. 2, the utility cart  20  comprises a top shelf  29  and a bottom shelf  32  having a plurality of support posts  35  secured therebetween. Although four (4) support posts  35  are shown, it would be readily apparent to those skilled in the art that three posts may be used to provide a triangular shaped cart, for example, or more posts may be used, such as three posts may be provided along the long axis of a rectangular shaped cart in order to provide more support for the top shelf. In addition it may be possible to provide a bottom shelf  32  and a top shelf  29  on a relatively elongated support post which support post would also support an intermediate shelf (not shown). As shown in FIGS. 3A and 3B the support post  35  of the present invention comprises a relatively hollow extruded member. Preferably the support posts are extruded from aluminum which provides strength in a relatively lightweight member.  
         [0027]    As illustrated in FIG. 3, FIG. 3A shows a support post  35  having a door  38  attached thereto, while FIG. 3B shows a support post  35  having a one piece panel cover  41  disposed therein, as will be more fully described hereinafter. The support post  35  comprises an outer hollow member  44  and an inner hollow member  47  secured therein. The inner hollow member  47  is operatively associated with the outer hollow member  44  by a plurality of, preferably four (4), generally ‘C’ shaped members  50  which are adapted to receive screws  53 , as shown in the exploded view in FIG. 2. The screws  53  pair through corresponding openings  55  in each of the top  29  and bottom  32  shelf in order to secure them to the support post  35 . In this manner the top and bottom shelf are substantially identical. Thus the difference between the various heights of the utility carts  20 A,  20 B and  20 C is provided by different substantial height support posts  35 . As the top  29  and bottom  32  shelf are identical for each embodiment and when compared with each other, this greatly simplifies the manufacturing of the present invention. The inner hollow member  47  of the support post  35  is adapted to receive an adjustable tray support arm  56  (which will be more fully described hereinafter in conjunction with FIGS.  4 - 7 ). The outer hollow member  44  of the support post  35 , in the embodiment shown, includes a pair of slots  59  for receiving either a hinged door  38  or a straight panel  41 , FIGS. 3A and 3B respectively. Preferably two slots  59  are provided and oriented with respect to each other such that when the support posts  35  are provided at each corner of the cart, as shown in FIG. 1, the slot at one corner is aligned with another slot  59  in the outer hollow member  44  of another support post  35  in an adjacent corner as will be more fully described hereinafter. While the slots are shown as being oriented at about 90° with respect to each other, it will be appreciated by those skilled in the art that the slots may have a different orientation such as for a three sided cart (120°), five sided cart (112°), six sided cart (60°) or more sided utility cart.  
         [0028]    As shown in FIG. 3A the slot  59 , at an opening portion  62  thereof, includes a relatively first circular portion  65 . As shown in FIG. 3A the circular portion  65  at the opening of the slot  59  is adapted to receive a circular member for securing either a straight panel  41  between support posts  35  or a hinged door  38 . For the hinged door  38  a hinge assembly  71  is constructed so as to be rotated therein. This will be more fully described hereinafter. As shown in FIG. 3B, when a one piece panel  41  cover is disposed between two support posts  35 , the panel is held secured to the support post such as by a rubber extrusion  74  which fits between the panel cover  41  and one side  77  of the first portion  65  at the opening of the slot  59 .  
         [0029]    As shown in FIGS.  4 - 7  the utility cart  20  includes at least one and preferably two vertically adjustable support arms  56  which are adapted to fit within an interior portion  80  of the inner hollow member  47  of the support post  35 . Two embodiments of the support arms  56  are shown in FIGS. 4 and 5 and each support arm  56  generally includes a vertical member  83 , which is substantially identical between the two embodiments shown, and an articulated arm  86  for supporting a tray  89 . In the embodiment shown in FIG. 4, the articulated support arm  86  has a relatively straight horizontal section  92  between the first angular section  95  at a first end rotatably connected  96  to the vertical member  83 , and a second angular section  98  at the second end opposite the first end connected to the vertical member  83 , which second angular section  98  is also preferably rotatably connected  101  to the underside of a support tray  89 . In the embodiment shown in FIG. 5, however the section between the first  95  and second  98  angular sections comprises a third angular section  104  such that the support tray  89  is generally disposed below the level of the articulated arm  86  connection to the vertical member  83 . The reasons for this will be more fully set forth hereinafter.  
         [0030]    As shown in the exploded view of FIGS. 4 and 5, the vertical member  83  in each embodiment includes a vertical adjustment mechanism  105  for the tray support arm  56  which generally comprises an outer tube  107  having a rod  110  freely movable within the outer tube  107 . The opposed ends  113  (lower in the Figures) and  116  (upper in the Figures) of the rod  110  extend beyond the respective ends of the outer tube. On the lower end of the vertical adjustment mechanism  105  is a wedge assembly  122  for frictionally securing the vertical member  83  of the tray support arm  56  within the interior portion  80  of the inner hollow member  47  of the support post  35 . Attached to the outer tube  107  at the engagement or first portion  119  of the vertical member  83  is a first wedge  125 , and a second wedge  128  secured to the engagement end  113  of the rod  110  which extends beyond the outer tube  107 . The second or lower wedge  128  is threaded and secured to the engagement end  113  of rod such as by a nut  134 . The rod  110  slides within a first tube nut  131  secured within the outer tube  107 . Disposed between the first  125  and second  128  wedge is an angular washer  137  which is slidably associated with the engagement end  113  of the rod  110 . The rod is free to slide within a hollow portion of the first wedge  125  and within the washer  137 . The opposite (upper) end  116  of the rod projecting above the outer tube  107  is operatively associated with button  140 , which button also passes through an opening  141  in the first angular section  95  of the articulated arm  86 . The button  140  is operably associated with the outer tube  107  by a spring  143 , and is secured to the rod  110  such as by a second tube nut  146 , which second tube nut also frictionally engages the inside of the outer tube  107 . The spring  143  therefore biases the button  140  in an upward direction (as shown in the Figures).  
         [0031]    The opposite end  116  of the rod  110  may be attached to the button  140  such as by a set screw (not shown). Referring now to FIGS. 7A and 7B, when the user presses down on the button  140 , it causes the rod  110  to slide within the outer tube  107  thereby urging the lower or second wedge  128  away from the upper first wedge  125 , thereby allowing the washer  137  to slide freely downward with the lower wedge (See  7 A). As shown in FIG. 7B in the engaged position, when an operator releases the pressure on the button  140  the spring  143  causes the button and rod  110  to move upward with respect to the outer tube  107 , thereby causing the lower wedge  128  to contact the angled washer  137  and forces the second wedge  128  into engagement with the washer  137 , and the washer  137  into engagement with the first wedge  125 . Preferably the wedge members  125 ,  128  are comprised of relatively soft material such as santoprene/TPE whereas the washer  137  is comprised of a relatively hard material such as nylon.  
         [0032]    When the second wedge  128  is forced into contact with the washer  137  which is then forced into contact with the first wedge  125 , the washer  137  forces the angled contacting portions of the respective wedge assemblies in a direction generally perpendicular to the vertical adjustment mechanism  105 . In this position the soft material of the wedges  125 ,  128  is frictionally engaged with the interior surface  80  of the inner hollow member  47  of the support post  35 . This frictional engagement is sufficient to secure the tray support arm  56  with respect to the utility cart  20 , regardless of whether a keyboard, pointing device or laptop computer is resting on the support tray  89 . In order to adjust the height of the tray support arm  56  with respect to the utility cart  20 , or to remove the tray support arm  56  from the cart altogether, the operator need to merely grasp both articulated arms  86 , pressing down on both buttons  140  to release the engagement of the wedge assemblies  122 , that is, of the first  125  and second  128  wedges with the washer  137 , thereby releasing the frictional engagement of the wedge assemblies  122  with the interior surface  80  of the inner hollow member  47 . The support arms can them be readily lifted upward and removed from the support posts  35 .  
         [0033]    In order to use the utility cart  20  without either of the support trays, as shown in FIG. 2, cap assemblies  152  can be used to cover each opening  55  provided in the top tray  29  through which the screws  53  are used to secure the top tray to the support posts  35 . By way of example in the drawing shown in FIG. 2, four caps are used, one for each support post. In order to attach the tray support arms  56  to the cart  26 , at least one of these caps  152  is removed. It may be desirable to use a single support arm having a relatively smaller tray having a single vertical member  83  attached thereon such that only one support post  35  need be accessible. However the invention will be described using two tray support arms which are attached at opposite ends to the underside of the tray support. Two of the caps  152  are removed so as to provide access to the inner hollow member  47  of two of the support posts  35 . Again as shown in the Figures the support arms are attached to the smaller side of a rectangularly shaped utility cart  20 . It will be readily apparent to those skilled in the art that the vertically adjustable support arms can be disposed within two support posts along a larger axis of the rectangular utility cart just as well. In this arrangement, an alternate cap  153  having a hole therein (FIG. 6) is placed over the openings  155  in the top shelf  29  and thus the support posts  35 , the hole in the cap  153  being generally aligned with the inner hollow member  47  of the support post  35 .  
         [0034]    An operator would only need to hold one articulated arm in each hand, pressing down on the button  140 , for example using a thumb on each button, thereby pushing the rod  110  and the lower second wedge  128  downward with respect to the tube  107  and the upper first wedge  125 . The vertical member  83  of the vertical adjustment mechanism  105  is then placed within the inner hollow member of the support post, then inserted downward into the support post according to the desired height of the user. When that height is reached the button  140  is released, the spring  143  thereby urging the rod  110  upward within the tube  107  and the lower wedge  128  upward into contact with the washer  137  and the washer into contact with the first upper wedge  125 . As the wedges are forced outward they frictionally engage the interior surface  80  of the inner hollow member  47  thereby locking the tray support arms  56  with respect to the support posts  35 .  
         [0035]    Due to the relatively tight tolerance between the adjustable support arms and the inner hollow members, misalignment of the support arms within the posts is minimized, if not eliminated all together. The support arms generally are required to be inserted within the inner hollow members of the support posts in substantial alignment due to the limited clearance available. The relatively soft material of the wedges, when contacted by the relatively hard material of the washer, forces the wedges outward into frictional contact with the inner surface of the inner hollow member. This frictional engagement is sufficient to prevent the support arms from sliding downward with respect to the support posts when equipment is placed on the top surface of the tray.  
         [0036]    [0036]FIG. 8 is a side view of the tray support shown in FIG. 4 attached to a utility cart. In this embodiment the horizontal section  92  between the first  95  and second  98  angular sections of the articulated arm  86  is relatively straight. Since the first angular section  95  is freely rotatably connected  96  to the outer tube  107  of the vertical member  83  of tray support arm  56  and the second angular section  98  is rotatably connected  101  to the underside of the support tray  89 , the tray can be rotated in a 360° arc with respect to the tray support arm  56  and the articulated arm  86  can be rotated 360° with respect to the vertical member  83 . Thus, the tray itself has two (2) degrees of 360° rotation with respect to the utility cart  20 .  
         [0037]    As shown in FIG. 9 the articulated arm  86  in this embodiment includes a third angular section  104  between the first  95  and second  98  angular sections. This third angular section  104 , drops below the height of the first angular section  95  connection  96  with the vertical member  83 , thereby limiting the rotational capabilities of the tray  89  with respect to the articulated arm  86  as well as the rotation of the articulated arm  86  with respect to the utility cart  20 . However for an ergonomic design it has been determined that this type of support arm is preferable when the utility cart is used for supporting a personal computer having a CPU unit which is mounted on the lower shelf. Depending on the size of the CPU, such as either in a flat or a tower configuration, the height of the cart is chosen accordingly.  
         [0038]    As shown in FIG. 10, an exploded view of a door assembly  38  for the utility cart  20  of the present invention is shown therein. The door assembly  38  comprises two door panels  155  and two hinge assemblies  71 , which are substantially similar. A cross-section of the hinge assembly  71  is shown in detail in FIG. 3A with respect to its connection to the outer hollow member  44  of the support post  35 . A first hinge mechanism  158  is secured to a door panel  155 , such as by a ‘U’ shaped member  161  which captures the door panel  155  therein. Set screws  164  or another attachment means, may be used, in order to secure the door within the ‘U’ shaped member  161 . A covering strip  167 , such as decorative double sided tape, may be used to cover the exposed ends of the set screws  164 . The opposite end of the first hinge mechanism  158  contains a circular portion  172  which is rotateably engaged with a second hinge mechanism  175 . One end  178  of the second hinge mechanism  175  includes a generally ‘C’ shaped member for rotatably engaging the circular portion  172  of the first hinge mechanism  158 , and the opposite end of the second hinge mechanism  175  contains a second circular portion  181  for engaging the circular opening  65  in the slot  59  of the outer hollow member  44  of the support post  35 . This second circular portion  181  of the second hinge mechanism  175  is also rotateably mounted with respect to the support post  35 . Thus two hinged or rotatable attachment mechanisms are provided for each door panel  155  so as to maximize the opening of the door assembly  38  with respect to the utility cart  20 . Each door panel preferably includes such a hinge assembly  71 .  
         [0039]    As is conventional, each door panel  155  is secured to each other by a lock mechanism  187 . A door pull  190  is provided on the accessible side  193  of the door panel  155  while a lock bar  196  is attached to the opposite side  199 . Preferably one of the door panels  155  includes a hole  202  for securing the lock mechanism  187  thereto. The door pull  190  is attached to the lock bar  196  by a door lock  205  which is preferably operated by a key (not shown) in a conventional door lock arrangement. The lock bar  196  is generally ‘L’ shaped such that when the door pull  190  is rotated, the larger end  208  of the ‘L’ shaped lock bar does not engage the underside of the top shelf  29 , whereas when rotated 90° it does so engage the edge of the top shelf  29 . When the key lock is operated, the door pull  190  is prevented from rotating thereby locking the door assembly  38  with respect to the top shelf  29  and thus the utility cart  20 .  
         [0040]    As shown in the exploded view of the utility cart in FIG. 2, preferably an inside corner of the support post  35  has a plurality of holes  211  therein. Preferably these holes  211  are at the same position in each of the support posts  35 . When considered with respect to FIG. 3, the holes  211  are disposed in the outer hollow member  44  in the area described by the slots  59  in the outer hollow member. These holes  211  are to accommodate support pegs (not shown) which are typically provided for adjustable shelving. A support peg is provided in corresponding holes  211  in each of the support posts  35  such that an intermediate shelf may be provided within the interior of the utility cart  20 . This shelf is adjustable as is well known in the art by positioning the support pegs in any of the corresponding holes provided in the vertical length of the support posts  35 . While eight (8) holes are shown in the exploded view in FIG. 2 more or less holes may be provided depending on the length of the support posts as well as the number of various positions for the shelf. Moreover more than one intermediate shelf may be provided between the top  29  and bottom  32  shelf utilizing the support peg and hole  211  arrangement.  
         [0041]    As shown, a door assembly  38  is attached to the elongated side of a rectangularly shaped utility cart  20 . The other side may also include a door assembly  38  or a single straight panel  41  which easily slides into corresponding slots  59  and is secured by respective rubber extrustion  74 , which straight panels may also be provided for the other side of the cart  20 . These panels  41  may also include slots (not shown) for wire management of electronic equipment and/or for ventilation for the equipment housed within the utility cart  20 .  
         [0042]    While specific embodiments of the invention have been described in detail, it would be appreciated by those skilled in the art that various modifications and alternations would be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the invention, which is to be given the full breath of the appended claims and any and all equivalents thereof.