Abstract:
A lifting chair, having a seat which is pivoted upward, being hinged along its front edge to help lift an individual who has trouble rising from an ordinary chair, also has arms which move upward during this pivoting process. Similarly, the seat and arms are moved downward to help the individual sit down. The linkage preferably is a parallelogram type preventing rotation of the arms as they are moved upward and downward along arcuate paths.

Description:
This application claims benefit of a prior-filed provisional application, Ser. No. 60/089,020, filed Jun. 12, 1998. 

   BACKGROUND OF THE INVENTION 
   1 Field of the Invention 
   The present invention relates to a chair for use by a physically impaired person, and, more particularly, to a chair including mechanical means assisting a physically impaired person in sitting down and in rising. 
   2 Background Art 
   A number of types of chair mechanisms have been made for helping physically impaired people in sitting down and in rising. Such mechanisms generally include a seat portion which is pivoted along its front edge so that it is raised to aid the user in getting up and lowered to aid him in sitting down. The seat portion may be motor driven, or manually moved with a spring aiding the upward motion. This mechanism may be incorporated within a chair extending to the floor or within a seat configured for placement on a chair or bench. With mechanisms of this type, only the chair seat moves. The adjacent arms, if there are any, remain stationary. What is needed is a method for raising and lowering the chair arms with the seat, so that the user can be provided with a source of support and stability as he rises and sits down. U.S. Pat. No. 4,929,022 describes a chair having a lift apparatus including a seat pivoted along its front edge, a foot pedal extending near the floor along the front of the chair, and a handle extending in front of each arm. A person sitting in the chair and wishing to rise transfers his weight to his feet, depressing the foot pedal, and simultaneously pulls back on the handles to cause the rear of the seat to pivot upward. Again, what is needed is a method for raising the arms of the chair as the user is rising and for lowering the arms of the chair as he is sitting down. 
   SUMMARY OF THE INVENTION 
   In accordance with a first aspect of the present invention, there is provided a lifting chair including a stationary frame, a seat movable upward and downward relative to the stationary frame in a predetermined manner, drive means for moving the seat in the predetermined manner, a first arm disposed adjacent a first side of the seat, and a first linkage extending between the seat and the first arm, wherein the first linkage moves the first arm upward as the seat is moved upward, and downward as the seat is moved downward. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a partially sectional side elevation of a lifting chair built in accordance with a first embodiment of the present invention, showing the mechanism tying the movement of the arms to the movement of the seat; and 
       FIG. 2  a side elevation of the mechanism tying the movement of the arms to the movement of the seat in a second embodiment of the invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  is a partially section side elevation of a lifting chair  8 , including a seat  10 , which is pivoted at a hinge axis  12  extending along its front edge  13 , being raised through an angle of approximately 90 degrees into the position indicated by dashed lines  14 . The seat is preferably lifted by a powered mechanism. For example, the seat may be lifted by a pneumatic bellows  15  or bag extending between the lower surface  16  of the seat  10  and a stationary plenum  17 , through which air is introduced into the bellows  15  by a pump  18  driven by a motor  19 . The seat is subsequently lowered by exhausting the air pumped into the bellows  15  through a solenoid valve  20 . The processes of pumping air into the bellows  15  and of exhausting air through the solenoid valve  20  are preferably performed in response to the operation of a switch mechanism  21  on a chair arm  22 . 
   The seat  10  may alternately be lifted by a pneumatic cylinder or by a mechanism including a motor driving a cam. Potential energy absorbed by the chair when a person sits down may be stored in a pneumatic or spring device to aid subsequently in the process of getting up. 
   This apparatus includes a chair arm  22  on each side of the seat  10 . Each chair arm  22  is connected to the seat  10  by means of an arm support member  23  extending outside the seat  10 . The arm support members  23  are each attached to a pivot rod  24 , which is pivotally mounted in a pair of bearing blocks  26  to extend under the seat  10 . The bearing blocks  26  are attached to the lower surface  18  of the seat  10 . Also on each side of the seat  10 , a crank  28  is attached to the pivot rod  24  to turn therewith. Each crank  28  is pivotally attached to a stabilizing arm  30  by means of a pivot pin  32 . Each stabilizing arm  30  is pivotally mounted at a stationary pivot pin  34 . 
   As the seat  10  is pivoted upward into the position indicated by dashed lines  16 , the stabilizing arms  30  are pulled upward into the position indicated by dashed lines  36  by the cranks  28 . The angular position of the cranks  28  is controlled by their pivotal connection to the stabilizing arms  30 . Preferably, the apparatus is configured so that, when the seat  10  is in its lowered position, each stabilizing arm  30  extends, between pivot points  34 ,  32 , parallel to a line  38  between the hinge pivot  12  and the pivot rod  24 , and so that each crank  28  extends, between pivot rod  24  and the pivot point  32 , in a direction parallel to a line  40  between the hinge pivot  12  and the pivot point  34 . Thus, the hinge pivot  12 , the pivot rod  24  and the pivot points  32 ,  24  are arranged as the vertices of a parallelogram. This parallogramatic relationship is retained as the seat is rotated upward into the position indicated by dashed lines  16 . Thus, each crank  28  retains its angular orientation as it is moved into the position indicated by dashed lines  42 . Since the arm support members  23  are connected to the cranks  28  through the pivot rod  24 , the arm support members  23  and the chair arms  22  attached thereto translate upward along an arcuate path  44  without rotation. That is, the arm support members  23  and the arms  22  move upward, without tilting, into the position indicated by dashed lines  46 . As the seat  10  is moved back down, the arms  22  move in the same way, but in the opposite direction, providing support for a person being lowered into the chair. 
   This apparatus may be used as part of a chair or as part of a portable device to be placed on a chair or other seat. In the latter application, the height of the mechanism is significant, since it is desirable to make the device as thin as possible, minimizing the vertical distance between the seat and the surface on which the device is placed. 
     FIG. 2  is a side elevation of a version of the apparatus with which this distance is minimized. In this apparatus, when the seat  50  is in its lowered position, the angular relationship between each stabilizing arm  52  and the associated crank  54  is too small to allow the initial movement of the crank  54  to start the movement of the stabilizing arm  52 . However, a slot  55  is provided in the stabilizing arm  52 , so that the pivot pin  56  extending between the stabilizing arm  52  and the crank  54  slides into the position indicated by dashed lines  58 , with the crank  54  being moved into the position indicated by dashed lines  60  as the seat  50  is initially raised into the position indicated by dashed lines  62 . Following this initial movement, the apparatus operates generally as described above in reference to  FIG. 1 , as the seat  50  is raised into the position indicated by dashed lines  64 . 
   While the invention has been described in its preferred form or embodiment with some degree of particularity, it is understood that this description has been given only by way of example, and that numerous changes in the details of construction, fabrication, and use may be made without departing from the spirit and scope of the invention.