Abstract:
One embodiment of the invention relates to an adjustable cart including a upper platform with a front portion and a back portion, a lower platform with a front portion and a back portion, rolling members for movably supporting the lower platform, a first supporting member connected to the back portion of the lower platform, and a first rotational pivot structure connecting the first supporting member to the back portion of the upper platform to permit pivoting about a first pivot location. The upper platform is configured to rotate about the first rotational pivot structure from a first position substantially parallel to the lower platform to a second position substantially perpendicular to the lower platform during which the first pivot location moves away from the lower platform.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     The present application claims priority to U.S. Provisional Patent Application Ser. Nos. 60/802,158, filed on May 22, 2006, and 60/899,008, filed Feb. 2, 2007, both of which are hereby incorporated by reference in their entireties. 
     
    
     FIELD  
       [0002]     This disclosure relates to adjustable carts and, in particular, carts that can be adjusted between different positions.  
       BACKGROUND  
       [0003]     Facilities maintenance personnel are known to use several different material handling carts in the same facility including multi-shelf utility carts, platform or hand trucks, and dollies. Different tasks may require different carts, which results in the personnel having to travel back and forth to find the correct cart for the job. Having multiple carts increases the time needed to find the correct cart. It also increases the storage space needed for carts. Some carts, such as hand trucks, have been developed that can be converted to different configurations. Such carts, however, often have limited uses and may require the removal of parts such as locking pins or supports to convert the cart from one configuration to another.  
       SUMMARY  
       [0004]     One embodiment of the invention relates to an adjustable cart including a upper platform with a front portion and a back portion, a lower platform with a front portion and a back portion, rolling members for movably supporting the lower platform, a first supporting member connected to the back portion of the lower platform, and a first rotational pivot structure connecting the first supporting member to the back portion of the upper platform to permit pivoting about a first pivot location. The upper platform is configured to rotate about the first rotational pivot structure from a first position substantially parallel to the lower platform to a second position substantially perpendicular to the lower platform during which the first pivot location moves away from the lower platform.  
         [0005]     Another embodiment of the invention relates to an adjustable cart including an upper platform with a front portion and a back portion, a lower platform with a front portion and a back portion, rolling members for movably supporting the lower platform, a first supporting member connecting the back portions of the first and lower platforms together via a first rotational pivot structure that pivots about a first pivot location, and a second supporting member connecting the front portions of the first and lower platforms together via a second rotational pivot structure. The upper platform is configured to rotate about the first rotational pivot structure from a first position substantially parallel to the lower platform to a second position substantially perpendicular to the lower platform during which the first pivot location moves away from the lower platform, the second rotational pivot structure slides on the second supporting member toward the lower platform, and the second supporting member rotates about a third rotational axis.  
         [0006]     Another embodiment of the invention relates to an adjustable cart including a lower platform, and at least two rotatable members rotatable along a first rotational pivot structure. Each of the two supporting members has an aperture, and the two rotatable members project at a predetermined angle from the lower platform at a first position. The cart further includes a spring loaded mechanism for locking the at least two rotatable members into the first position. The spring loaded mechanism includes a pedal rotatable along a second rotational pivot structure, at least two link mechanisms connected to the pedal; a spring coupled to the link mechanisms for biasing the pedal in a depressed position; and a locking pin connected to each link mechanism for insertion into one of the apertures of a corresponding rotatable member. The locking pin is configured to be pulled out of the aperture of the corresponding rotatable member when the pedal is moved from the depressed position to a pressed position such that the rotatable members can pivot around the first rotational pivot structure.  
         [0007]     Another embodiment of the invention relates to an adjustable cart including upper and lower platforms, rolling members for movably supporting the lower platform, a supporting member connecting portions of the first and lower platforms together; a first rotational pivot structure for allowing rotation of the upper platform from a first position substantially parallel to the lower platform at a first predetermined distance to a second position substantially perpendicular to the lower platform, and a second rotational pivot structure for allowing rotation of the upper platform from the second position substantially perpendicular to the lower platform to a third position substantially parallel to the lower platform at a second predetermined distance. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]      FIG. 1  is an isometric view of a cart according to an embodiment of the invention in a first configuration with an upper platform and a lower platform that are generally horizontal and spaced apart from each other.  
         [0009]      FIG. 2  is an isometric view of the cart of  FIG. 1  in a second configuration with the upper platform in a generally vertical orientation.  
         [0010]      FIG. 3  is an isometric view of the cart of  FIG. 1  in a third configuration with the upper platform and the lower platform in a generally horizontal orientation and the upper platform resting on the lower platform.  
         [0011]      FIG. 4  is an isometric view of the first supporting member of the cart of  FIG. 1 .  
         [0012]      FIG. 5  is an isometric view of a portion of the first supporting member of  FIG. 4  showing brackets used to couple the first supporting member to the upper platform.  
         [0013]      FIG. 6  is an isometric view of the first supporting member coupled to the upper platform in the cart of  FIG. 1 .  
         [0014]      FIG. 7  is a partially exploded view of the second supporting member and sliding joints of the cart of  FIG. 1 .  
         [0015]      FIGS. 8 and 9  are isometric views of one of the sliding joints of  FIG. 7 .  
         [0016]      FIG. 10  is an exploded view of one of the sliding joints of  FIG. 7 .  
         [0017]      FIG. 11A  is an isometric view of one of the sliding joints of  FIG. 7  showing a retractable protrusion in an engaged position.  
         [0018]      FIG. 11B  is an isometric view of one of the sliding joints of  FIG. 7  showing a retractable protrusion in an disengaged position.  
         [0019]      FIGS. 12A-12E  are isometric views of the cart of  FIG. 1 , showing the cart being reconfigured from a first configuration to a second configuration.  
         [0020]      FIG. 13A-13C  are side views of the cart of  FIG. 1  showing the top portion of the first supporting member as the cart is moved from a first position to a second position.  
         [0021]      FIG. 14  is an isometric view of the spring loaded mechanism of the cart of  FIG. 1  with locking pins that are engaged with apertures in the first supporting member.  
         [0022]      FIG. 15  is an isometric view of the spring loaded mechanism of the cart of  FIG. 1  with locking pins that are disengaged with apertures in the first supporting member.  
         [0023]      FIG. 16  is an isometric view of the spring loaded mechanism of the cart of  FIG. 1  with locking pins that are disengaged with apertures in the first supporting member and the first support member folded down in a generally horizontal orientation. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0024]     Referring in general to the figures and in particular to  FIGS. 1-3  a cart  10  is shown according to an exemplary embodiment. The cart  10  preferably includes an upper platform  12 , a lower platform  14 , rolling members  15  coupled to the lower platform  14 , a first supporting member  16  and a second supporting member  18  that are pivotably coupled to the upper platform  12  and lower platform  14 , and a locking mechanism  60 . The cart  10  preferably is configured to be adjustable between three configurations or positions. In the first configuration or position (e.g., two shelf cart configuration), shown in  FIG. 1 , the upper platform  12  and lower platform  14  are generally parallel and spaced apart to form two shelves. In a second configuration or position (e.g., platform truck configuration, etc.), shown in  FIG. 2 , the upper platform  12  is rotated down and is generally perpendicular to the lower platform  14 . In a third configuration or position (e.g., storage configuration, etc.), shown in  FIG. 3 , the upper platform  12  folded against the lower platform  14  such that the upper platform  12  and lower platform  14  are generally parallel. Rolling members  15  (e.g., wheels, casters, etc.) coupled to the lower platform  14  allow a user to more easily move the cart  10  and any objects being supported by the cart  10  in any of the three configurations.  
         [0025]     The upper platform  12  and lower platform  14  are generally flat members that are configured to support an object being transported with the cart  10 . The upper platform  12  can include an integrally formed handle  13  that is configured to facilitate the movement of the cart. According to an exemplary embodiment, the upper  12  and lower  14  platforms are formed from an injection molded polymer such as a polypropylene or other comparable plastic resin. According to other exemplary embodiments, the upper  12  and lower  14  platforms may be formed from a metal, fiberglass, or other suitable material.  
         [0026]     The first supporting member  16  is pivotably coupled to a back portion of the upper platform  12  and a back portion of the lower platform  14 . The second supporting member  18  is pivotably coupled to a front portion of the upper platform  12  and a front portion of the lower platform  14 . According to an exemplary embodiment, the first  16  and second  18  supporting members are formed at least partially from steel tubes with generally circular cross-sections. According to other exemplary embodiments, the first  16  and second  18  supporting members may be formed from a high-strength polymer, fiberglass, or other suitable material. According to other exemplary embodiments, the first  16  and second  18  supporting members may be formed from components with other cross-section shapes (e.g. oval, square, etc.).  
         [0027]     Referring now to  FIGS. 4-6 , the first supporting member  16  is shown according to an exemplary embodiment. The first supporting member  16  includes two generally parallel outer tubes  20  that serve as the back legs of the cart  10 , two telescoping inner tubes  22  that are provided inside the outer tubes  20 , a cross member  24  that is coupled to the outer tubes  20 , two links  26  that are pivotably coupled to the cross member  24 , and brackets  28  and  29  that couple the links  26  and inner tubes  22  to the upper platform  12 . The first supporting member  16  further includes bottom portions or feet  90  that are coupled to the lower platform  14 .  
         [0028]     The outer tubes  20  and inner tubes  22  are generally hollow members with a circular cross-section. The outer tubes  20  have an inner diameter that is greater than the outer diameter of the inner tubes  22  such that the inner tubes  22  nest within the outer tubes  20  and extend past the top of the outer tubes  20 . The cross member  24  is oriented generally perpendicular to the outer tubes  20  and is coupled to the outer tubes proximate to the top of the outer tubes  20 . Two bars or links  26  are pivotably coupled to the cross member  24  proximate to the outer tubes  20 . The inner tubes  22  and the links  26  are pivotably coupled to the back portion of the upper platform  12  with brackets  28  and  29 , respectively. As will be described in more detail later in the application, brackets  28  and  29  provide pivot points that move upward vertically as the front portion of the upper platform  12  is rotated downward.  
         [0029]     Referring now to  FIG. 7 , the second supporting member  18  is shown according to an exemplary embodiment. The second supporting member  18  includes two generally parallel legs  30  and a connecting portion  32  that is generally perpendicular to the legs  30  and is received by openings in the lower platform  14  to couple the second supporting member  18  to the lower platform  14 . Sliding joints  40  are coupled to the legs  30  and the upper platform  12  to couple the second supporting member  18  to the upper platform  12 . Plugs or ends  34  may be provided to close the open ends of the legs  30  and/or the connecting portion  32 . Apertures  36  are provided in the legs  30  that may be aligned with corresponding features in the sliding joints  40 .  
         [0030]     Referring now to  FIGS. 8-11B  sliding joint  40  is shown according to an exemplary embodiment. The sliding joint  40  includes a main body  42 , a retractable protrusion shown as a U-shaped pin or latch  43 , a button  44  that allows a user to move the latch  43 , a bushing  45 , a bracket  46  that facilitates coupling the sliding joint  40  to the upper platform  12 , a retaining member  47 , a biasing member  48 , and an outer faceplate  49 .  
         [0031]     The housing or main body  42  of the sliding joint  40  is a generally L-shaped body that includes a first opening  50  (e.g., shaft, hole, bore, etc.) that receives one of the legs  30  of the second support member  18 , and a second opening  52  that receives at least a portion of the latch  43 . According to one exemplary embodiment, the latch  43  is a generally U-shaped body that includes one arm or end that is received within the second opening  52  and an opposite arm or end that engages an aperture  54  in the main body  42  proximate to the first opening  50 . A button  44  is provided proximate to one end of the second opening  52 . A bushing  45  is held in the second opening  52  by an inwardly extending wall or flange  56 . The bushing  45  includes an outwardly extending flange  57  that contacts flange  56  to limit the movement of the bushing  45  in the second opening  52 . An end of the latch  43  passes through the bushing  45  and contacts the button  44 . The latch  43  extends past the sliding joint  40  through an opening in the side wall  51  of the upper platform  12  to rotatably couple the sliding joint  40  to the upper platform  12 . The latch passes through a bracket  46  opposite of the main body  42 . A retaining member, shown as a c-clip  47  engages a groove  55  in the bushing  45  to couple the bracket  46  to the main body  42 . A biasing member, shown as coil spring  48  is provided between the bushing  45  and the button  44  to bias the button  44  away from the bushing  45 . A faceplate  49  is coupled to the main body  42  to retain the bushing  45 , coil spring  48 , and button  44  in the second opening  52 . The faceplate  49  includes an inwardly extending wall  86  that includes an opening or slot  87  that is configured to receive a corresponding tab  88  that extends outward from the button  44  when the button  44  is in a depressed or rest position.  
         [0032]     Referring now especially to  FIGS. 11A and 11B , the operation of the latch  43  is shown in more detail. As shown in  FIG. 11A , in a first position, one end of the latch  43  is disposed in the aperture  53  in the main body  42  and extends into the first opening  50 . The end of the latch  43  further engages the aperture  36  in the leg  30  received within the first opening  50  to prevent the sliding joint  40  from sliding along the longitudinal axis of the leg  30 . As shown in  FIG. 11B , in a second position, the button  44  is pushed into the second opening  52 . The button  44 , compresses the coil spring  48  and disengages the latch  43  from the aperture  36  in the leg  30  of the second supporting member  18 . When the latch  43  is disengaged from the aperture  36 , the sliding joint is allowed to slide freely along the longitudinal axis of the leg  30 .  
         [0033]     Once button  44  is pressed, tab  88  on button  44  disengages from the slot  87  of cover  49 . The button  44  is coupled to the latch  43  and, in turn, to the upper platform  12  and the faceplate  49  is coupled to the main body  42  and, in turn, to the second supporting member  18 . As the second supporting member  18  rotates relative to the upper platform  12 , the tab  88  is rotated away from the slot  87  and rides along the end of the wall  87 , causing the button  44  to remain retracted within the second opening  52 . When the upper platform  12  and the second supporting member  18  rotates to a locking position (e.g., the first, second, or third position), the tab  88  engages the slot  87 , allowing the latch  43  to return to a locking position.  
         [0034]     Referring now to FIGS.  12 A-E, the cart  10  is shown being converted from a first position or configuration to a second position or configuration. A user begins by pressing the buttons  44  on the sliding joints  40  to disengage the latches  43  from the apertures  36  in the second supporting member  18 . The front portion of upper platform  12  and the sliding joints  40  is allowed to move downward as the second supporting member  18  pivots on the connecting portion  32 . During the conversion from the first position to the second position, the sliding joints  40  move down the legs  30  of the second supporting member  18  until the upper platform  12  is partially rotated, as shown in  FIG. 12C , then begin sliding back up the legs  30 . As the front portion of the upper platform  12  rotates downward, the back portion of the upper platform  12  pivots on brackets  28  and  29  and moves away from the lower platform  14 . The movement of the back portion of the upper platform  12  relative to the lower platform  14  allows the length of the upper platform  12  to be greater than the distance between the upper platform  12  and the lower platform  14  when the cart is in the first configuration. The upper platform is rotated downward to a generally vertical orientation and the second supporting member  18  is rotated to a generally horizontal orientation to convert the cart  10  to the second position. The upper platform  12  includes a coupling mechanism, shown as protrusion  58  on the front portion of the upper platform  12 , shown best in  FIG. 3 . The protrusion  58  engages a recess  59  provided in the lower platform  14  to help retain the cart in the second position.  
         [0035]     Referring now to FIGS.  13 A-C the first supporting member is shown in more detail as the cart is adjusted from the first position to the second position. As the upper platform  12  (not shown in FIGS.  13 A-C for clarity) is rotated downward, brackets  29  rotate toward the back of the cart  10  on links  26 . Because brackets  28  and  29  are both coupled to the upper platform  12  and the distance between brackets  28  and  29  is fixed, brackets  28  are forced upward as brackets  29  move toward the back of the cart  10 . The inner tubes  22  telescope out of the outer tubes  20  as the brackets  28  move upward. Because the brackets  28  and  29  move upward as the upper platform  12  is moved from the first position to the second position, the distance between the upper platform  12  and the lower platform  14  may be less than the length of the upper platform  12 .  
         [0036]     Referring now to  FIGS. 14-16 , a spring-loaded locking mechanism  60  is shown according to an exemplary embodiment. The locking mechanism  60  is configured to selectively fix the first supporting member  16  in a generally vertical orientation (i.e., in the first and second configurations of the cart  10 ). The locking mechanism includes a switch or pedal  62  that is moveable between a first and second position, a linkage  64  that is coupled to the pedal, locking pins or latches  66  that are coupled to the linkage  64  and are actuated by the pedal  62  as it moves between the first and second positions, and a biasing member, shown as spring  68  that biases the locking mechanism towards the first position.  
         [0037]     The pedal  62  is received in a opening in the back portion of the lower platform  14  and pivots between a first position and a second position along pivots  70 . In the first position or depressed position, shown in  FIG. 14 , the pedal  62  presents a generally continuous surface with the top of the lower platform  14  and the locking pins  66  are engaged with the first supporting member  16 . In the second position or pressed position, the pedal  62  is pressed downward and the locking pins  66  are disengaged from the first supporting member  16 , allowing it to rotate downward as shown in  FIG. 3 . The pedal  62  includes downwardly extending arms or walls  72  and a shaft or rod  74  that is received by openings in the walls  72 .  
         [0038]     The linkage  64  is coupled to the pedal  62  and the locking pins  66 . According to an exemplary embodiment, the linkage include a first link  76  coupled to the pedal  62 , and a second and third links  78  coupled to the first link and to the locking pins  66 . The first link  76  is pivotably coupled to the rod  74  and moves towards the front of the cart  10  as the pedal  62  is moved from the depressed position to the pressed position. The locking pins  66  include a striker portion  80  and an arm  82 . The locking pins  66  are coupled to the ends of the second and third links  78  and rotate about a pivot  84  as the pedal  62  is moved between a depressed position and a pressed position. The spring  68  is coupled to the first link  76  and to the lower platform  14 . The spring  68  is extended as the locking mechanism  60  moves from a first position to a second position. For clarity, the spring  68  is shown only coupled to the first link  76  in  FIGS. 14-16 .  
         [0039]     As shown in  FIG. 14 , when the locking mechanism  60  is in the first position, the striker portions  80  of the locking pins  66  engage apertures  92  in the bottom portions  90  of the first supporting member  16 . The first supporting member  16  is coupled to the lower platform  14  at pivot points  94  (e.g., with bolts) and rotates about pivot points  94 . The locking pins  66  prevent the first supporting member  16  from rotating when the locking mechanism is in the first position.  
         [0040]     As shown in  FIG. 15 , when the pedal  62  is pressed down (e.g., by a user&#39;s foot), the first link  76  is pulled towards the front of the cart  10  and the spring  68  is extended. The second and third links  78  rotate the locking pins  66  about the pivots  84 , disengaging the striker portions  80  from the apertures  92  in the bottom portions  90  of the first supporting member  16 . When the locking mechanism  60  is in the second position, the first supporting member  16  is allowed to rotate downward about the pivot points  94  as shown in  FIG. 3  and  FIG. 16 . In the third configuration or position, shown in  FIG. 3 , the cart  10  provides a generally flat wheeled platform. In the third position, shown in  FIG. 3 , the cart  10  is configured to be able to be stood on its side (e.g., for storage).  
         [0041]     For purposes of this disclosure, the term “coupled” means the joining of two components (electrical or mechanical) directly or indirectly to one another. Such joining may be stationary in nature or movable in nature. Such joining may be achieved with the two components (electrical or mechanical) and any additional intermediate members being integrally formed as a single unitary body with one another or with the two components or the two components and any additional member being attached to one another. Such joining may be permanent in nature or alternatively may be removable or releasable in nature.  
         [0042]     Although the invention has been described above by reference to certain embodiments of the invention, the invention is not limited to the embodiments described above. Modifications and variations of the embodiments described above will occur to those skilled in the art in light of the above teachings.