Abstract:
A safety device for a wheelchair, or similar device, is disclosed. The device is a wheel assembly directed to preventing rearward movement of the device when the person exits or enters the device thus preventing potential accidents.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention is directed to the field of wheelchairs and other medical devices. In particular, the present invention is directed to a brake to allow the user to safely exit from the wheelchair or walker. One problem with the existing devices is that when the user stands up or tries to exit or enter the wheelchair or other medical device, there is the possibility that the wheelchair or walker will start to roll backwards. When that happens, the user may not be entirely out and may fall backwards as the device rolls in that direction. The available devices may include manual brakes on the wheels in an attempt to prevent such falling. However, often times a caregiver may forget to set the brake and the patient may fall if he or she attempts to exit or enter on his or her own. The object of the present invention is to solve this problem by providing an automatically engaging safety device. 
       SUMMARY OF THE INVENTION 
       [0002]    The present invention is directed to an automatic safety device for a medical device such as a wheelchair, walker, shower chair or hospital bed. The present invention will prevent the device from rolling backward out from under the patient during entry to or exit from the device. The device is automatically engaged by the downward force produced from the patient&#39;s weight upon entry or exit. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0003]      FIG. 1  is a plan view of an embodiment of the present invention installed on a wheelchair. 
           [0004]      FIG. 2  is a plan view of an embodiment of the present invention. 
           [0005]      FIG. 3  is a plan view of an embodiment of the present invention. 
           [0006]      FIG. 4  is a plan view of an embodiment of the present invention. 
           [0007]      FIG. 5  illustrates an embodiment of the present invention in use. 
           [0008]      FIG. 6  illustrates an embodiment of the present invention in use. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0009]    The present invention will now be described in terms of the presently preferred embodiment thereof as illustrated in the drawings. Those of ordinary skill in the art will recognize that many modifications may be made to the described embodiment without departing from the spirit or scope of the present invention as claimed. 
         [0010]    A wheelchair  10  is illustrated in  FIG. 1 . The wheelchair  10  comprises a seat  12 , two large rear wheels  14  and two small front wheels  11 . The seat  12  comprises a frame  17 , side armrests  18  and push handles  19 . In the available wheelchairs, a user in the seat  12  will tend to push down and backward on the side arm rests  18  to exit or enter the wheelchair  10 . When that happens if the manual brake isn&#39;t engaged the small front wheels  11  or the large rear wheels  14  tend to begin to roll backwards possibly causing the person to fall as the wheelchair moves backward out from under the user. 
         [0011]    As shown in detail in  FIG. 2 , the present invention comprises a wheel assembly  16  that prevents the wheelchair  10  from rolling backward as the person enters or exits the wheelchair  10 . The wheel assembly  16  comprises an upper tubular leg  20  that adjustably connects to the bottom of the wheelchair frame  17  by means of a bracket  22 . The bracket  22  comprises an adjustable circular strap  24  that can be tightened around the wheelchair frame  17  by means of a screw  26 . By adjusting the screw  26 , the circumference of the strap  24  is adjusted to fit the circumference of the frame  17 . The upper tubular leg  20  is fitted with a button  21  that is adapted to engage one of a plurality of mating openings  23  on the lower tubular leg  27 . The lower tubular leg  27  is adapted to slidingly receive upper tubular leg  20 . The appropriate height from the wheelchair frame  17  to the ground can be adjusted in this manner. 
         [0012]    A first bracket  28  is rotatably connected to the lower tubular leg  27  by means of a conventional nut  29  and bolt  30 . In addition, a spring  31  is connected between the bolt  29  and bracket  28 . A second bracket  32  is rigidly connected to the first bracket  28  by means of a second nut  33  and bolt  34 . A wheel  36  and axle  38  is connected to an open end  32  of bracket  28 . In addition, a generally star-shaped sprocket  40  is also disposed on the axle  38 . The sprocket  40  comprises a plurality of spokes  41  between the wheel  36  and bracket  28 . A spring-loaded lever  42  is connected to the bracket  32  and is adapted to engage the sprocket spokes  41 . 
         [0013]    Two of the wheel assemblies  16  are attached to the wheelchair frame  17  as shown in  FIG. 1 . The use of the sprocket  40  and lever  42  allows the wheelchair  10  to be moved forward or sideways or in a circular motion. However, if the person gets up or sits down and the wheels start to move in a backward direction, the lever  48  will engage the nearest spoke  41  on the sprocket  40  and prevent rearward movement of the wheel. In addition, the downward force from the weight of the person on the armrests  17  will cause the first bracket  28  to pivot downward on the tubular leg  18  and collapse the leg onto the floor. As shown in  FIGS. 5 &amp; 6 , at that point, there will be no further movement of the wheelchair. After the patient enters or exits, and the downward force from the person&#39;s weight is removed, the spring arm  42  will cause the wheelchair  10  to return to it original position. 
         [0014]    The wheel assembly  16  has been described in connection with a wheelchair  10 . However, it is contemplated that the present invention can be easily adapted to other medical devices as well, such as a shower chair, a medical bed or a walker. 
         [0015]    Those of ordinary skill in the art will recognize that the foregoing merely describes the preferred embodiment of the present invention and that many obvious modifications may be made thereto without departing from the spirit or scope of the present invention as set forth in the claims.