Abstract:
A wheelchair cart configured for rollable transportation while carrying medical gas or other equipment is provided having a linkage assembly operable for linking the cart with a wheelchair while allowing the wheelchair/cart assembly to pass over uneven surfaces. The cart allows a single person to connect the cart to a wheelchair and transport the two simultaneously. The cart is configured such that equipment that should be transported with the patient and is often physically connected to the patient (e.g. ventilators, IV&#39;s, and monitors) is stored and transported on the cart. Risks associated with disconnecting the patient from vital medical equipment are minimized by eliminating the typical separate transportation of an equipment cart and a wheelchair by more than one person, which may result in a stretching or breaking of the attachment lines between the patient and the equipment.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is broadly concerned with improved carts particularly designed for use in conjunction with wheelchairs. More particularly, the invention pertains to such carts wherein the carts may be releasably attached to any conventional wheelchair through an attachment system adapted to accommodate travel over uneven surfaces. In preferred forms the cart is configured to hold and transport items necessary for the care of the person utilizing the wheelchair. The present invention allows one caregiver to transport a patient in a wheelchair while simultaneously transporting other items necessary for the patient&#39;s care all while minimizing the risk of disconnecting the patient from any equipment connected to them. 
     2. Description of the Prior Art 
     In the health care field, much time and labor is spent transporting patients in wheelchairs and hospital gurneys. Many patients needing to be transported have other items or equipment associated with their health care needs that should be transported simultaneously with the patient. Often, the patient is physically attached to some items or equipment such as intravenous tubes (IV&#39;s), heart monitoring equipment, oxygen, ventilators, and respirators. Serious problems may arise if the patient is disconnected from these items, even if the disconnection is a relatively short and temporary one. Furthermore, some disconnections are not immediately noticeable by the healthcare provider, especially if the patient is sleeping, unconscious or unable to communicate effectively. Transporting these patients and their associated items generally requires the labor of at least two people, one to push the wheelchair or gurney and at least one to transport the other equipment. This presents the problem of moving the patient in unison with the equipment and minimizing the possibility of disconnecting the patient from any connected equipment since all people transporting must move together in a coordinated fashion. This is often very difficult to do if transporting the patient requires maneuvering around corners, over uneven surfaces, through crowded corridors or doors, or in places where there is only a small area available for any needed maneuvering (such as a hospital or nursing home room). If the people transporting do not move the patient in unison with their connected equipment, the risk of disconnecting the patient from the equipment rises. Furthermore, many health care facilities have responded to increasing costs and overhead by reducing the size of their labor force resulting in a shortage of labor available to transport patients. This may encourage the cutting of corners by employing just one person to transport both patient and equipment when more than one may be required to safely transport the patient and their equipment using currently available transportation equipment. 
     Other problems occur, using currently available transportation equipment, due to the transferring of equipment from a bedside to a carrier for transportation. If the equipment is heavy, there is a risk of backstrain to the healthcare provider. Furthermore, the equipment may be accidentally dropped or operational settings may be inadvertently changed if the controls are accidentally contacted by the caregiver. If there is not a convenient place to mount the equipment during transportation, the equipment may be placed in a position, including underneath the wheelchair or gurney, that reduces the visibility of any display the equipment may have. Additionally, owing to a lack of space, the equipment may have to be placed in an area that is inconvenient to access in emergency situations. This is especially true when equipment is mounted under a wheelchair or gurney for transportation. Mounting equipment under a wheelchair also subjects the equipment to possible damage due to incontinent patients. 
     Consequently, there is a need for an apparatus that reduces the number of people required to transport a patient when there is other equipment that must be transported simultaneously with the patient. There is also a need for an apparatus that minimizes the possibility of disconnecting a patient from any equipment to which they are connected. Another need in the art is an apparatus that minimizes the possibility of inadvertently changing the operational settings of that equipment during transportation. What is also needed is an apparatus that may be used as a standalone bedside unit to store equipment and a transportation unit which can be quickly and easily connected to a wheelchair for transportation. What is still further needed is an apparatus configured to hold equipment at a normal operating level allowing clear visibility at all times and easy access in emergency situations. Finally, what is needed is an apparatus designed to be connected to a wheelchair or gurney that is configured to hold and transport equipment such that one person can efficiently and safely transport both a patient and their equipment. 
     SUMMARY OF THE INVENTION 
     The present invention overcomes the problems outlined above and provides an apparatus configured to be releasably connected to a wheelchair or gurney which allows for a single caregiver to transport a patient and any associated equipment safely and efficiently. In addition, the present invention minimizes the risks associated with accidentally disconnecting a patient from medical equipment by minimizing strain on the connecting tubes or wires caused by increasing the distance between the patient and the equipment. A further advantage of the present invention is that by virtue of attaching a cart to a wheelchair, the resulting combination makes a stable walking trainer for patient therapy. Another advantage of the present invention is that the cart may be used as the normal bedside holder of the equipment, that is, the cart may act as a stand-alone unit thereby reducing the number of times that a person has to lift the equipment and place it either onto a separate cart for transportation or another cart or table for standalone use. By having the equipment already located on the cart, the risk of dropping the equipment when transferring it from its bedside position to the cart is reduced. This also reduces the danger of backstrain on the person transferring the equipment from the bedside to its transportation carrier. The connecting assembly system of the present invention provides a quick and easy way to couple the cart with a wheelchair and advantageously allows for accommodation of strain when the wheelchair and cart are moving over uneven surfaces. 
     The present invention is also configured to hold the equipment at its normal operating height allowing the display to remain visible at all times during transportation. The present invention also allows for easy access to the equipment in emergency situations and eliminates the risk of equipment damage due to incontinent patients. Another advantage of the present invention is that accidental contact with equipment resulting in changes to operational settings ofthe equipment is minimized. Finally, the present invention allows unconnected patient transport for several hours since the cart is configured to hold oxygen cylinders and a large external battery to power any equipment. 
     The apparatus of the present invention comprises a cart configured to be releasably connectable to a wheelchair or gurney; as used herein, “wheelchair” refers to conventional wheelchairs, gurneys where a patient is transported in a recumbent position, and all other wheeled patient transport devices. The cart is also configured to hold oxygen cylinders and other equipment at a normal operating level that is visible at all times and easily accessible in emergency situations. The cart includes wheels to facilitate transportation. In preferred forms, the cart will have more than one connecting assembly system in order to allow connection to a wide variety of different sizes and shapes of conventional wheelchairs and gurneys. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A preferred embodiment of the present invention is described in detail below with reference to the attached drawing figures, wherein: 
     FIG. 1 is a fragmentary side view of a preferred cart in accordance with the present invention attached to a conventional wheelchair by a frame pin assembly system; 
     FIG. 2 is a fragmentary top view of a preferred cart in accordance with the present invention taken along uneven vertical line  2 — 2  of FIG.  1  and illustrating the cart and two preferred connecting assembly systems; 
     FIG. 3 is a is a fragmentary vertical cross sectional view taken along line  3 — 3  of FIG. 2 showing the tubular foot lever cooperating with the frame pin assembly in both phantom and full lines; 
     FIG. 4 is another fragmentary vertical cross sectional view taken along line  3 — 3  of FIG. 2 showing the tubular foot lever cooperating with the frame pin assembly in both phantom and full lines; 
     FIG. 5 is a fragmentary top view of a cart in accordance with the present invention showing a linkage arm assembly connected to the downstrut of a wheelchair; 
     FIG. 6 is a fragmentary vertical cross sectional view taken along line  6 — 6  of FIG. 5 illustrating a preferred attachment pin assembly securing a linkage arm assembly which is extended and connected to a tubular downstrut of a conventional wheelchair; and, 
     FIG. 7 is a fragmentary side view of a preferred linkage arm taken along line  6 — 6  of FIG. 5 showing the linkage arm assembly connected to the downstrut of a wheelchair and accommodating an uneven transportation surface. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The following description and examples set forth preferred embodiments of the present invention. It is to be understood, however, that these examples are provided by way of illustration and nothing therein should be taken as a limitation upon the overall scope of the invention. 
     Turning now to the drawings wherein like reference numerals are used for all figures, FIG. 1 depicts a preferred cart  10  in accordance with the present invention releasably attached to a wheelchair  12 . The cart  10  includes a metallic apertured tubular cart frame  14 , base  16 , upright member  18 , handle  20 , u-shaped oxygen holder brackets  22 , oxygen holder base  24 , castors  26 , a frame pin linkage assembly  28  and a linkage arm assembly  30 . 
     Cart  10  comprises a tubular cart frame  14  made up of side marginal tubular legs  31  astride and supporting base  16 . Each leg  31  presents an open forward end  32  formed by the interior surfaces  34  of the respective legs  31  and an annular cap  35  covering the legs  31  but not the forward ends  32 . The base  16  is secured to the frame legs  31  and acts as a mounting deck for upright member  18  which is configured to extend vertically from cart base  16 . Upright member  18  may be provided with a pair of sidewalls  33  supporting rearwardly extending shelves (not shown); these shelves provide a convenient place to store equipment at at a level that is easily visible as well as accessible. Upright member  18  is also configured and positioned such that it is difficult for the caregiver to accidentally contact stored equipment and change operational settings on any of such equipment. 
     Cart handle  20  is attached to and extends rearwardly from upright member  18  and provides an ergonomically efficient position from which the cart  10  can be pushed. A pair of u-shaped oxygen holder brackets  22  are also attached to the sidewalls  33  of member  18  (as shown in FIG. 5) and are configured to releasably secure gas cylinders  36 . 
     The bottom of each cylinder  36  may be supported by the cart base  16  or by the depending U-shaped base  24 . In order to provide additional clearance for cylinders  36 , a pair of cylinder openings  38  are provided through the cart base  16 , as shown above. Base  24  depends from cart base  16  below the openings  38  and is configured to support the bottoms of cylinders  36 . Alternatively, there may be a separate base for each cylinder  36  or base  24  may extend for substantially the entirety ofthe width of cart base  16 . 
     Castors  26  are secured to and depend from base  16  and legs  31 . Preferably, castors  26  are attached to the legs  31  and base  16  near each comer of the cart  10 , so as to provide cart  10  with stability during transportation and when under load stress. 
     The present invention preferably includes two separate but not necessarily mutually exclusive linkage assemblies. A preferred frame pin linkage assembly  28  operable with a particular range of wheelchairs  12  which incorporate custom location holes  46 ,  48  through their tubular foot levers  42  is illustrated in FIGS. 3 and 4. The assembly  28  cooperates with the forward open ends  32  of the frame legs  31 , and includes frame pin openings  44  in each leg  31 , and frame pins  50  having heads  52  and shafts  54 . Pin openings  44  extend through the top surface of frame legs  31  as illustrated. The pin openings  48  are of a larger diameter than the corresponding openings  46 . The open ends  32  of the frame legs  31  have a larger diameter than the wheelchair tubular foot levers  42  so as to receive the latter  42  therein. Vertical pin endstops  56  are located respectively within each open end  32  to limit the insertion of tubular foot lever  42  thereon. 
     Frame pin shafts  54  are insertable into frame pin openings  44 , 46  such that when the two openings  44 ,  46  are in alignment, the shafts  54  extend through both openings  44 ,  46 . Shafts  54  are also extendable through pin openings  48  as shown in FIG. 3, especially when cart  10  and wheelchair  12  are moving over uneven surfaces. Frame pins  50 , when shafts  54  are inserted through pin openings  44 ,  46  are configured to securely retain levers  42  within open ends  32 , thereby coupling the wheelchair  12  with the cart  10 . 
     The configuration of assembly  28  allows for pivoting between the cart  10  and wheelchair  12  when coupled together as illustrated in FIGS. 3 and 4. When the wheelchair  12  encounters an upward slope (FIG.  3 ), levers  42  rock or pivot within open ends  32 . Before pivoting, shafts  54  normally extend through pin openings  44  and pin openings  46 . As an upward slope is encountered, levers  42  pivot upward and shafts  54 , preferably with bullet-shaped noses  58  at their distal ends  60 , locate and extend through pin openings  48 . This reduces the loading of shear forces on shafts  54  at pin openings  46 . Shafts  54  remain extended through pin openings  44 ,  46 ,  48  until the upward slope evens out at which time, levers  42  pivot down and shafts  54  slide out of pin openings  48 , but remain extended through pin openings  46 . 
     When wheelchair  12  encounters a downward slope (FIG.  4 ), levers  42  rock or pivot within open ends  32 . Shafts  54  remain extended through pin openings  44  and  46  and cart  10  remains securely attached to wheelchair  12 . This pivotability greatly reduces the possibility of the wheelchair  12  becoming accidentally detached from the cart  10  and thereby straining or disconnecting any wires or tubes connecting the patient with the equipment. 
     The linkage arm assemblies  30  are another preferred linkage system. Assemblies  30  are configured to allow cart  10  to be attached to a wide range of conventional wheelchairs  12 . Each linkage arm assembly  30  preferably comprises an attachment pin  62 , a bottom linkage arm  64 , a pivoting hinge  66 , a top linkage arm  68 , a pivoting center joint  70  between the arms  64 ,  68 , a clamp  72 , a clamp tightener  74 , a plate  76 , a plate wingnut  78 , a beveled washer  80 , and an attachment pin lock nut  82 . As shown in FIGS. 1 and 2, linkage arm assemblies  30  may be in a neutral or unconnected position wherein they rest upon either frame  14 , base  16  or upon the linkage arm rests  84 . Linkage arm rests  84  are secured to the legs  31  and allow the linkage arm assemblies  30  to be secured when the assemblies  30  are in the neutral position. Alternatively, linkage arm assemblies  30  may be in an extended use position as shown in FIGS. 5,  6  and  7 . 
     Attachment pins  62 , having proximal ends  86  and distal ends  88 , extend through associated legs  31  and are attached to linkage arms  64  via pivoting hinges  66 . Hinges  66  include elongated pins  90  which allow the linkage arms  64  to be moved through approximately an 180° arc relative to the base  16 . Plates  76  lie adjacent frame  14  and have two openings, namely pin openings  92  and plate wingnut slots  94 . The pins  62  are attached to plates  76  and extend through pin openings  92  and frame  14  where they are secured by means of beveled washers  80  and attachment pin locknuts  82 . Washers  80  receive attachment pins  62  therethrough and lie adjacent to the frame  14  bottom. Locknuts  82  threadably receive distal ends  88  and when tightened, lie adjacent to washers  80 . Wingnuts  78  are operable to secure plates  76  adjacent to frame  14 . Slots  94  allow the linkage arm assemblies  30  to be swung radially about upright axes in or out to accommodate wheelchairs  12  of different widths while still holding relatively fixed positions once attachment of the cart  10  to a wheelchair  12  is completed and wingnuts  78  are tightened. 
     Linkage arm assemblies  30  are moveable about attachment pins  62 . Linkage arms  64  are swingable from the neutral position, wherein the linkage arm distal ends  96  are aligned toward the cart back end  98 , to the extended position, wherein the distal ends  96  are aligned toward the cart front  100 , by pivoting about the pivoting hinges  66 . Distal ends  96  are attached to top linkage arm proximal ends  102  through pivoting centerjoints  70 . Joints  70  include joint pins  104  which allow pivoting of linkage arms  64  relative to linkage arms  68 . Linkage arms  68  are pivotable about joints  70  allowing for accommodation and relieving of loads when traversing uneven surfaces. Linkage arms  68  terminate in clamps  72  at distal ends  106 . The clamps  72  are configured to releasably secure cart  10  to a wheelchair  12  through opposing adjustable jaws  108 ,  110  and clamp tighteners  74 , i.e. the jaws  108 ,  110  engage tubular downstruts  112  of a wheelchair  12  with tighteners  74  for tightening the jaws. Preferably, star-type knobs are used as the tighteners  74  to facilitate tightening and loosening of jaws  108 ,  110 . 
     When a slope is encountered, the wheelchair  12  will begin its descent or ascent prior to the cart  10  thereby increasing the load on linkage arm assemblies  30 . This increased load will pivot the joints  70 , thereby accommodating and lessening the load. This also contributes to the stability of the cart  10  when connected to a wheelchair  12  by allowing the castors  26  to remain in contact with the ground over a wider range of loads and inclines. Linkage arms  64  and pivoting hinges  66  participate in relieving loads in an identical fashion. Advantageously, pivoting at the center joints  70  and hinges  66  contributes to the safe transportation of the patient by greatly reducing the possibility of accidentally disconnecting the cart  10  from the wheelchair  12  and the patient from any equipment to which they may be connected. 
     A particularly preferred embodiment of the present invention includes more than one linkage assembly to facilitate attachment to any conventional wheelchair regardless of size. Another preferred embodiment of the present invention comprises a kit operable for converting conventional carts to carts attachable to wheelchairs for rollable transportation. The kit includes at least one linkage assembly including a wheelchair attachment device, a cart attachment device, and a linker spannable between either of the attachment devices and a wheelchair. The attachment devices may include clamps, hooks, ties, hook and loop fasteners, clasps, clips, fasteners, or any other device or combination of devices capable of connecting to a wheelchair or cart. The linker may be any object capable of spanning between the cart and the wheelchair including, but not limited to linkage arms, rods, belts, cables, ropes, bands, wires, beams, lines, straps, chains and combinations of any of these. 
     The present invention therefore provides a quick and easy way to couple a cart  10  with a wheelchair  12  so that both may be simultaneously transported safely and efficiently by one person. The cart  10  is configured to hold equipment necessary for patient care both during and after patient transport thereby negating the need for standalone tables or shelves to hold the equipment. The equipment is held in a position that is easily accessible in emergency situations, visible at all times during transportation, difficult to accidentally contact and change operational settings during transportation, and not susceptible to damage due to incontinent patients. Furthermore, the present invention reduces the risk of backstrain caused by loading equipment onto carts for transportation and unloading this equipment to a stand-alone table once transportation is complete. Risks of damaging equipment due to dropping equipment during loading, unloading or transporting equipment are also minimized. Finally, risks associated with accidentally disconnecting a patient from any equipment are reduced by providing a coupled cart  10  and wheelchair  12  which is transportable as a single unit, even over uneven surfaces. The present invention therefore minimizes the risk that during the transporting of a patient connected to equipment, the lines connecting the patient to that equipment will be stretched and possibly become detached.