Invalid transfer device
This invention relates to an invalid transfer device wherein an individual can control the operation of the device while at the same time be carried by the device. 
     In the past a wheel chair has been proposed as a means of transport for moving an individual who is an invalid. The wheel chair is electrically powered by batteries and a control coupled to the batteries is operable upon an input from the individual operator to impart motion and direction to the wheel chair. Although providing some independence for the individual in moving about, there is no provision for getting into and out of the wheel chair. Consequently, assistance is generally required before the individual can operate the wheel chair. 
     Various other devices have been proposed which transport an individual from place to place. However, these devices require that the individual receive assistance from a third party before the indivudual can be disposed on the device, and also when the individial wants to dismount from the device. Examples of these devices can be found in U.S. Pat. Nos. 4,255,823; 4,119,164; 4,117,561; 3,999,228; 3,807,520; 3,469,269; 3,189,345; 3,137,869; 3,112,001; 2,991,485; and 578,368. 
     In addition, when an individual is operating a transfer device it is important that the device operate smoothly and carry the individual in a stable position. An unforseen dismount from the device during operation could seriously injure the individual or prevent the individual from reaching his destination. 
     The present invention provides an improvement over the devices in the above-mentioned patents. In particular, the present invention enables an individual to independently position himself or herself on the transfer device without requiring the individual to stand up. The transfer device includes a wide range of vertical positions for the individual so that transfer to and from a bed, chair, floor or commode is easily undertaken with the transfer device of the present invention. And finally, the transfer device provides an anti-sway assembly to substantially eliminate instability during operation so that the individual is smoothly carried on the transfer device. 
     It is an object of the present invention to provide a simple structure which provides movement for an invalid in a safe manner while at the same time enabling the invalid to position himself or herself in a multiplicity of positions in the absence of assistance from a third party. 
    
    
     The invention will now be described with reference to the accompanying drawings wherein 
     FIG. 1 is a side perspective view of the invalid transfer device and 
     FIG. 2 is an illustration of the device being operated by an invalid. 
    
    
     The invalid transfer device 10 includes a base 12 with a front end 14 and a rear end 16. The front end 14 includes a pair of front wheels 18 and the rear end includes a pair of rear wheels 20. The front end defines a uniform width A extending to the rear end 16 which defines a larger uniform width B. The pair of front wheels 18 are attached to a plate or tube 22 at the front edge of the device 10 and are generally of the universal castor type. The pair of rear wheels 20 are larger than the pair of front wheels with both pair of wheels including non-scuff tires. The base 12 is made from a pair of tubular members joined at the front by the plate or tube 22 and joined at the rear by a plate or tube 24, see FIG. 2. 
     A support assembly 26 extends upwardly from the rear end of the base 12 and includes a vertical support 28, a boom member 30 and a connecting link 32. The boom member 30 forms an angle relative to a horizontal axis which is about 30°. The vertical support is fixedly secured to the plate or tube 24 with a pair of angular supports 34 reinforcing the fixation thereto. The boom member 30 is fixedly carried by a first pair of flanges 36 in spaced relation to the vertical support 28 for a purpose hereinafter defined. The connecting link 32 extends between the boom member 30 and the vertical support 28 to reinforce the fixed positions thereof in a 30° relationship. 
     In order to support an individual on the transfer device 10, a carrier assembly 40 is provided. The carrier assembly 40 comprises a seat 42, a backrest 44 and a bar 46 coupled to the backrest and seat via a pair of chains or ropes 48 or other suitable coupling. The bar 46 is coupled to a cable 50 to control the elevation of the carrier assembly 40 relative to the base 12. The cable extends from the carrier assembly 40 to an end pulley 52 attached to the end of the boom member 30 via a second pair of flanges 54. The boom member 30 is tubular with a bore therethrough for receiving the cable. The first pair of flanges 36 support an intermediate pulley 56 so that the cable 50 partially wraps around the pulley 56 to extend into a bore formed within the vertical support 28. 
     The pulleys 52 and 56 could be covered to enclose the cable within the support assembly. An aperture 58 formed at an intermediate height on the vertical support 28 receives a pulley 60 so that the cable 50 can wrap around the pulley 60. The pulley 60 forms a part of a winch which is operable to unwind or windup the cable around the pulley 60 or, in the alternative, the cable can partially wrap around the pulley 60 and extend to a winch separate from the pulley 60. 
     In order to operate the transfer device, a control unit 70 is attached to the base 12 at the rear end 16. The control unit includes a solenoid package 72, a battery 74, a motor package 76, a second motor 78, and a control head 80. The motor package 76 includes separate motors for each rear wheel. The control head 80 is connected via a flexible wire 82 with the solenoid package 72, which in turn is connected to the motor package 76, the second motor 78, and the battery 74 via suitable electrical leads. A cover 85, shown in phantom, is provided to enclose the control unit 70, except for the control head 80 and a part of the wire 82. The control head can be removed from the cover for hand operation by the individual when disposed in the carrier assembly 40. A platform 84 is secured to the wide rear end 16 of the base 12. The platform 84 carries the solenoid package 72, the battery 74 and the motor package 76. A bracket 86 is secured to the vertical support 28 adjacent the aperture 58. The pulley 60 and the second motor 78 are supported on the bracket 86. A pair of legs 88 and 90 extend diagonally from the bracket 86 to the platform 84 to reinforce the bracket 86 and also to further reinforce the vertical support 28. The motor package 76 cooperates with both rear wheels 20 via separate belts 92 (only one of which is shown) so that each wheel 20 can be operated separately. Consequently, the motor package 76 can alter the direction of the transfer device as well as move the transfer device forward and backward. The motor 78 is coupled to the pulley 60 to form a winch to control movement of the cable 50 and in turn control elevation of the carrier assembly 40. 
     To prevent the carrier assembly 40 from swinging away from a position directly over the front end, an anti-sway assembly 100 extends between the vertical support 28 and the carrier assembly 40. The anti-sway assembly 100 comprises a collar 102 fixed to the vertical support 28. A pair of lateral rods 104 and 106 extend outwardly from the collar 102, or in the alternative, the rods 104 and 106 could be fixed to the vertical support 28 itself. A pair of arms 108 and 110 connect with respective rods and extend in the direction of the front end to approach each other. A cross member 112 connects with both arms to form a spacing 114 with the arms and rods. The connecting link extends through the spacing. A cylinder 116 is secured to the cross member 112 and the ends of the pair of arms 108 and 110. A telescoping rod 118 is received within the cylinder 116 and is secured to the carrier assembly 40, or to the cable adjacent the carrier assembly 40. The pair of arms can pivot vertically relative to the pair of lateral rods 104 and 106 or, in the alternative, the pair of arms and rods can pivot vertically relative to the collar 102, provided the telescoping rod 118 remains secured to the carrier assembly when the latter is being moved up or down relative to the base 12. 
     As shown in FIG. 2, the invalid transfer device carries an individual substantially above the front end of the base 12 and the anti-sway assembly 100 retains the individual in this position at all times so that the device will not tip over. In this position the individual can readily lift himself above and directly over a bed for easy separation from the carrier assembly. The narrow front end is readily extended into small areas while the wide rear end with the weight of the control unit over the rear end provides stability for the transfer device. With the control unit carried at the rear end of the base, it is also possible for the individual to be lowered to a position directly over the floor. Consequently, the range of vertical movement for the individual is from the floor to the boom member 30. 
     A limit switch 120 is attached to the flanges 54. The limit switch 120 cooperates with the telescoping rod 118 when the latter contacts the switch to stop further elevation of the carrier assembly at its highest position. 
     In the alternative, the winch 60 could be replaced with a hydraulic device incorporated into the base and coupled to the cable, or, a hydraulic device could be substituted for the connecting link 32 to control movement of the carrier assembly. The cover 85 could also extend laterally at the base to enclose the latter.