Elevator Chair

It is often desirable to provide assistance to a person who is attempting to move from a sitting position in a chair to a standing position. Age, infirmity, or various disabilities often render it difficult for persons to rise out of a chair from a sitting to a standing position without assistance.

In moving the occupant of a chair from a sitting to a free standing position, it is critical that both positions provide adequate and comfortable support if the chair is to function efficiently. The chair should be designed to distribute pressure to the back, buttocks and thighs of a user in the standing position. Also, as the chair moves an occupant from a sitting to a standing position, it is often critical that the chair backrest not apply shear stresses to the back of an occupant. It is very important that the upper leg of the occupant be positioned as the chair rises to support the weight of the occupant in the standing position as weight is transferred from the chair to the legs. Once the legs are properly positioned, then it is desirable for the chair to tilt forward to aid in transferring the weight of the occupant to the occupant's legs.

In the past, the design of chairs which have been developed to move occupants upwardly from a sitting position has been directed toward providing the upward movement and has not concentrated on positioning the legs and torso of the occupant and then tilting the chair for transition from the sitting to the standing position. U.S. Pat. No. 4,249,774 to Andreasson discloses a chair of this type which requires an occupant to slide forward over a projecting seat.

A number of wheelchairs have been developed to raise an occupant from a sitting to a standing position and to support the occupant in the standing position, but these chairs are designed for continued occupant support in a standing position and not to facilitate transition from the chair to a free standing, unsupported position. U.S. Pat. Nos. 5,211,414 and 5,401,044 to Galumbeck are illustrative of wheelchairs of this type.

It is a primary object of the present invention to provide a chair having a drive mechanism which can be controlled by an occupant to change the position of the occupant from sitting to a free standing position.

Another object of the present invention is to provide a chair which moves its user from a sitting position to a comfortable, supported standing position which will enable a user to safely enter and leave the chair.

It is yet another object of the present invention to provide a chair which includes a seat that is driven between two vertical positions above a lowermost seated position by a seat drive mechanism. In the intermediate position, the seat is configured to provide both user support and comfort while positioning the upper legs of the user to receive the user's weight, while in the uppermost position, the seat tilts forward to transfer the user's weight.

It is a still further object of the present invention to provide a chair having a drive mechanism which drives the chair upwardly from a first to a second position. As the chair moves upwardly, the back and seat remain in the position they assumed when the occupant was sitting, and a front section of the seat in contact with an occupant's legs between the hip and knee angles downwardly to position the legs to receive an occupant's weight. Once the occupant's legs are positioned, the back and seat tilt forward to transfer the occupant's weight from the chair to the legs.

FIG. 1 is a view in right side elevation of the elevator chair of the present invention;

FIG. 2 is a view in left side elevation of the elevator chair of the present invention;

FIG. 3 is a view in side elevation of the elevator chair of the present invention in the uppermost position thereof;

FIG. 4 is a perspective view of a second embodiment of the elevator chair of the present invention;

FIG. 5 is a perspective view of the elevator chair of FIG. 4 in a partially raised position; and

FIG. 6 is a view in side elevation of the elevator chair of FIG. 3 in a second raised position.

Referring to the drawings, the elevator chair of the present invention indicated generally at 10 includes a seat assembly 14 having a cushion supporting frame 16 which is formed into a front section 18 and a rear section 20 which are preferably equal in size. The rear seat section may however be equal in size or wider from front to rear than the front seat section 18 to comfortably support an occupant in a sitting position without the support provided by the front seat section. The front section of the cushion supporting frame 16 is pivotally secured to the rear section by a hinge 22 which extends transversely across the frame. The front and rear sections 18 and 20 of the cushion supporting frame are substantially rectangular sections with crossbars or a bottom wall to support a front section cushion 24 and a rear section cushion 26 which are mounted on the front and rear sections respectively.

Secured to the rear section 20 of the cushion supporting frame at the free end opposite to the hinge 22 is a back rest frame 28 which again is a substantially rectangular frame having frame cross beams to support a back cushion 30. An armrest 32 secured to the back rest frame projects outwardly therefrom on either side of the back cushion 30, and is supported by a support post 34 secured to the rear section 20 of the cushion supporting frame. Projecting downwardly from the rear section of the cushion supporting frame beneath the back rest frame is a linkage supporting bracket 36.

When the seat assembly is in the lowermost position as shown in FIGS. 1 and 2, the cushion supporting frame 16 rests upon a rectangularly shaped support member 38 which is mounted inwardly from the linkage supporting bracket 36. The support member 38 may be secured to a vertical support post 40 which extends upwardly from a horizontal support surface 42. This horizontal support surface could, for example, be a support surface attached to the frame of a motorized scooter for propelling an occupant, and in this case, a handle bar control for the scooter will project upwardly in front of the elevator chair 10. Alternatively, the support surface 42 could be a pedestal for resting on a floor or other horizontal surfaces, and in some instances, the pedestal 40 is only one of a number of supporting legs attached to the rectangular support member 38.

An electrically powered fractional gear motor 44 is mounted upon the rectangular support member 38 and includes a motor drive shaft 46 which extends outwardly from opposite sides of the gear motor. The drive shaft 46 is connected to rotate a short link 48 which is pivoted at 50 to a drive link 52. The end of the drive link 52 remote from the pivot 50 is angled upwardly at 54 at an angle of approximately 45.degree. to the remainder of the drive link and is pivotally connected at 56 to a point substantially at the center of a first pivoted link 58. The pivoted link 58 is a straight, elongate link having a first end pivotally connected at 60 to the linkage supporting bracket 36 and a second end pivotally secured at 62 to the rectangular support member 38. The first pivoted link 58 is positioned behind and slightly inwardly of a second straight, elongate pivoted link 64 of substantially the same length. An upper end of the second pivoted link is connected to the linkage supporting bracket 36 by a pivot 66 and the remaining end of the second pivoted link is connected to the rectangular support member by a pivot 68. The pivots 66 and 68 are positioned in line with but forwardly and spaced from the pivots 60 and 62 so that the first pivoted link and second pivoted link are always substantially parallel. When the elevator chair 10 is in the downward seating position shown in FIGS. 1 and 2, the second pivoted link 64 overlies the first pivoted link 58.

The linkage construction on opposite sides of the elevator chair 10 is identical, and consequently in FIG. 2, like components to those shown in FIG. 1 are designated by the same reference numeral in combination with the designation "b".

The front section 18 of the cushion supporting frame 16 is pivoted at 70 to a bracket 72 that is secured to the front of the rectangular support member 38. It will be noted in FIGS. 1 and 2 that the front section 18 and rear section 20 of the cushion supporting frame are substantially equal in size, and, as shown by the broken lines in FIG. 1, the rear section is positioned substantially under the hips of an occupant while the front section extends outwardly under the occupant to a point spaced rearwardly of the occupant's knees.

To raise the elevator chair from the lowermost sitting position shown in FIGS. 1 and 2 to a second raised position and then to the uppermost standing position shown in FIG. 3, a motor control panel 74 is provided on one of the arms of the elevator chair. The motor control panel includes a first switch 76 which operates the fractional gear motor to drive the motor drive shaft 46 in FIG. 1 in a clockwise direction to raise the seat assembly 14 and a second switch 78 which reverses the fractional gear motor 44 to drive the drive shaft 46 in a counterclockwise direction in FIG. 1 to lower the chair from the position of FIG. 3 to that of FIGS. 1 and 2. The motor control panel 74 is connected in known manner between a power supply (not shown) and the fractional gear motor.

As will be noted from FIG. 3, when the fractional gear motor is activated to raise the seat assembly 14 from a first position of FIGS. 1 and 2 to a second position and then to its uppermost position, the front seat section 18 is drawn downwardly about the hinge 22 by the bracket 72 while the rear seat section and the seat back remain substantially in the sitting position of FIGS. 1 and 2 as shown by FIG. 6. The front seat section and the front section cushion 24 angle outwardly from the hinge 22 to raise the upper leg 80 of an occupant from a seating position to a position where the upper leg is slightly bent between the hip 82 and the knee 84. The first and second pivoted links 58 and 64 are dimensioned in length to drive the rear seat section 20 and the rear section cushion 26 further upwardly from the second position to an extent where the rear seat section and rear seat cushion angle downwardly toward the hinge 22. The rear seat section is drawn downwardly by the hinge 22 and the front seat section as the links 58 and 64 force the rear of the seat upwardly. As can be seen from FIG. 3, the rear seat cushion 46 supports the buttocks and hip area of a user but now angles them so that the user may slide forward out of the seat assembly. It will be apparent that as the user moves forward, the upper leg section 80 has been positioned to receive the user's weight, and furthermore, it is important to note that the user's hip section and back are still retained substantially perpendicular as they are in a sitting position, so that the user is not driven forward as the seat assembly rises from the first to the second position. If desired, a stop 86 may be provided on the rectangular frame 38 to engage the second pivoted link 64 and stop the seat assembly in the desired uppermost position.

It will be noted that the short link 48, which was behind the drive link 52 with the seat assembly in the lowermost position of FIGS. 1 and 2 is extended by rotation of the drive shaft 46 in the uppermost position of the seat assembly in FIG. 3.

Referring to FIGS. 4 and 5, a second embodiment of the elevator chair of the present invention indicated generally at 90 is shown, and structural elements of this chair which correspond to those shown in FIGS. 1-3 are identified by the same reference numeral. As in the case of the elevator chair 10, the elevator chair 90 includes a seat assembly 14 having a cushion supporting frame 16 which is formed into a front section 18 and a rear section 20. The front section of the cushion supporting frame is pivotally secured to the rear section by a hinge 22 which extends transversely across the frame. The front and rear sections of the cushion supporting frame are substantially rectangular sections with cross bars or a bottom wall to support a front section cushion 24 and a rear section cushion 26. One of these crossbars for the rear section 20 of the cushion supporting frame is shown in broken lines at 92 and is positioned adjacent the hinge 22.

In the elevator chair 90, arm rests 94 are supported by support bars 96 secured to the rear section 20 of the cushion supporting frame on opposite sides of the chair. The support bar 96 extends below the rear section 20 and mounts one end of an elongated link 98 at a pivotal attachment point 100. In FIGS. 4 and 5, the support linkage on one side of the chair is shown, but this structure is duplicated on the opposite side of the chair.

The elevator chair 90 is supported by a surface engaging support frame 102 which includes triangular supporting members on opposite sides of the chair, each of which has an elongate ground engaging leg 104 which extends in spaced relationship beneath the seat assembly 14 for substantially the extent of the seat assembly. Each triangular supporting member includes a forward support bar 106 extending upwardly from the forward end of the ground engaging leg 104 and an angled support bar 108 which angles from the top of the forward support bar 106 to the rear end of the ground engaging leg 104. A motor supporting crossbar 110 extends between the ground engaging legs 104 of the triangular supporting members on the opposite sides of the elevator chair 90.

The forward end of the front section 18 for the cushion supporting frame 16 is pivoted at 112 to the top of each triangular supporting member, and the forward end of the link 98 is pivoted to a triangular supporting member at a pivot point 114 spaced below the pivot 112.

Mounted on the motor supporting crossbar 110 is a reversible electric motor which is geared in known manner to drive a drive screw 118 that is connected to the crossbar 92 to both support and control movement of the elevator chair 90. Control buttons for the motor 116 are provided at the forward end of each of the chair arms 94 with a button 120 connected to the motor 116 by a circuit 122 to raise the chair and a button 124 connected to the motor by a circuit 126 to reverse the motor and lower the chair. The provision of the control buttons 120 and 124 at the forward ends of each arm of the elevator chair 90 is noteworthy, for these buttons allow the chair occupant to grasp both chair arms and to manipulate the chair throughout its range of movement without releasing the grip on either chair arm. This is extremely important for elderly and infirm occupants.

As will be noted from FIG. 5, activation of the control button 120 causes the motor 116 to extend the drive screw 118 to drive the seat assembly 14 upwardly. This causes the link 98 to pivot about the pivots 100 and 114, while the pivot 112 draws the front section 18 of the seat assembly downwardly about the pivot 22. It will be noted that the rear section of the seat assembly 20 and the back rest frame 28 maintain the same position as the seat rises that they maintained in FIG. 4 for a sitting position of the occupant. This allows the occupant to be fully supported in a sitting position as the front section 18 of the seat assembly drops and angles forward to bring the occupant's legs into a free standing support position. Then, as illustrated in FIG. 3, the chair 90 of FIG. 5 continues to rise until the back section 20 of the seat assembly and the back rest frame 28 are angled forwardly as shown in FIG. 3 due to the downward pull exerted by the pivot 112 on the front section 18 of the seat assembly and on the pivot 22 as the screw 118 drives the seat assembly further upwardly. Thus, once the occupant's legs are positioned to receive the occupant's weight in a free standing position, the rear section of the seat assembly tilts forward with the back frame 28 to aid in transferring the weight of the occupant from the chair to the occupant's legs.