Abstract:
The lift chair has a chair fame pivotally connected to a chair base for pivotal movement about a chair frame horizontal axis. A liner actuator pivots the chair frame about a chair frame horizontal axis. Left and right arm rests are pivotally attached to the chair frame by hinge and ratchet assemblies. The hinge portions have an arm rest axis at the rear of the arm rests. The ratchet portion permit forward ends of the arm rests to be raised as required and hold the arm rests in selected positions to assist a person to stand after the chair frame has been pivoted upward about the chair frame horizontal axis. The arm rests are pivoted to their upper limit to release the ratchet assemblies and free the arm rests to pivot to their lower positions.

Description:
TECHNICAL FIELD 
     The invention is in a lift chair, for physically challenged individuals, with arm rests that are pivotally adjustable to assist an individual in assuming a standing position. 
     BACKGROUND OF THE INVENTION 
     Lift chairs for lifting physically challenged individuals from a sitting position to a standing position are well known. These chairs are generally well padded easy chairs with arm rest. The lifting mechanisms employed vary substantially. There are some lift chairs that manipulate the seat cushion only. Other chairs lift only the arm rests vertically upward. Lifting the arm rests only works for an individual that has substantial upper body strength. Moving the arms to a higher position helps a person lift his body onto his feet with his arms. 
     A more common lift chair has a chair frame that is pivotally attached to a support base. The chair frame is pivoted relative to the support base about an axis at the front of the chair and adjacent to the floor. A variety of power lift mechanisms have been employed to pivot the chair frame of these lift chairs relative to the base. The power lift mechanisms include rotatable screws and fluid cylinders. Some of the mechanisms are manually powered while others are electrically powered. 
     Pivoting a chair frame upward about a horizontal axis below the forward edge of a seat cushion causes the arm rests to pivot with the chair frame. The forward ends of the arm rests move forward and downward toward the floor. The rear ends of the arm rests move upward away from the floor and forward. At the same time a persons trunk is raise and moved forward relative to his or her feet. The end result is that the portions of arm rests that a person would push against with his hands to move to a standing position moves to an angle in which it slopes downward and forward and also moves away from his or her shoulders. In this arm rest position the use of a person&#39;s arms and upper body to move to a standing position is rendered more difficult and less effective for many individuals. 
     Padded wide arm rests are difficult to grasp. A person with minimal grip strength may find it almost impossible to grip such an arm rest. When a padded wide arm rest is covered by a material with a relatively slick or smooth surface, a person with substantial grip strength may find that his hands slip on the arm rest rather than helping to lift his body to a standing position. The fact that the smooth surfaces of arm rests on some lift chairs also slope forwardly and downwardly makes it difficult for individuals, that rely on upper body strength, to move from a sitting position to a standing position. 
     SUMMARY OF THE INVENTION 
     The lift chair has a chair base. A chair frame is pivotally attached to the chair base for pivotal movement about a horizontal frame axis. The frame axis is positioned adjacent to a lower forward portion of the chair frame. A seat pad and backrest pad are connected to the chair frame. A linear actuator is connected to the chair base and to the chair frame for pivoting the chair frame about the horizontal frame axis between a seat pad lowered position and a seat pad raised position. Left and right hinge and ratchet assemblies have anchor arms fixed to the chair frame. Adjustable arms are pivotally attached to the anchor arms by hinge pins for pivotal movement about an arm rest axis. Each hinge and ratchet assembly includes a pivoted bolt that is engageable with a plurality of ratchet teeth to hold an adjacent arm in a selected position and to limit pivotal movement of an adjustable arm to a lower position. Bolt lockouts inactivate the bolts to permit pivotal movement of the adjustable arms to a lowered position. A left arm rest is attached to one of the adjustable arms with its rear end adjacent to the arm rest axis. A right arm rest is attached to the other adjustable arm with its rear end adjacent to the other adjustable arm. 
     The ratchet assemblies permit the arm rests to be pivoted to positions in which they are horizontal when the seat cushion is in a raised position. The arm rests can be used to provide assistance in moving to a standing position when the arm rests are in a raised horizontal position. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     The presently preferred embodiment of the invention is discloses in the following description and in the accompanying drawings, wherein: 
     FIG. 1 is a perspective view of a lift chair, with adjustable arm rests, in a lowered position for sitting; 
     FIG. 2 is a perspective view of the lift chair with both the chair and the arm rests in raised positions; 
     FIG. 3 is a side elevational view of an arm rest pivot and ratchet mechanism, with parts broken away, in a lowered position; 
     FIG. 4 is an elevational view of the pivot and ratchet mechanism, in a fully raised position, with parts broken away; 
     FIG. 5 is an elevational view of the pivot and ratchet mechanism in a raised position with the ratchet pivoted bolt held in a released position; and 
     FIG. 6 is an expanded view of the pivot and ratchet mechanism. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The lift chair  10  has a chair frame  12 . The chair frame  12  is pivotally connected to a chair base  14  for pivotal movement about a horizontal frame axis  16 . A seat pad  18  and a backrest pad  20  are attached to the chair frame  12 . Two arm rests  22  and  24  are also attached to the chair frame  12 . A wide covered pad  26  is fixed to the upper portion of each of the arm rests  22  and  24 . 
     Exposed surfaces of the chair frame  12  are covered by a cover  28 . Padding may be provided between the chair frame  12  and the cover  28  if desired. The cover for the chair frame  12  can be a fabric material, leather, plastic or other suitable material. The cover for the seat pad  18 , the backrest pad and the arm rest pads  26  can be fabric, leather, plastic or other suitable material. 
     The chair base  14  is a metal frame. Two rear floor contact legs  30  and two front floor contact legs  32  are integral parts of the chair base  14 . Only the right rear floor contact leg  30  is shown in FIG.  2 . The chair base  14  is symmetrical about a central fore and aft vertical plane. The left rear floor contact leg  30  is therefore substantially identical to the right rear leg  30  that is shown. Additional legs can be provided if desired. 
     A linear actuator  34  is pivotally attached to the chair base  14  and the chair frame  12  in a known manner. Hydraulic linear actuators as well as screw type linear actuators are used on lift chairs  10 . Both types of linear actuators  34  are operated electrically on modern chairs. These actuators  34  pivot the chair frame  12  about the axis  16 . Preferably the tilt position is positively controlled in both directions by the actuator  34 . 
     The left and right arm rests  22  and  24  are pivotally attached to the chair frame  12  by hinge and ratchet assemblies  40 . These assemblies  40  provide a horizontal arm rest axis  42  at the rear edge of each arm rest  22  or  24 . In the normal use position the arm rests  22  and  24  rest upon arm rest support surfaces  36  and  38  on the chair frame  12 . The ratchet assemblies  40  have an anchored arm  44  and an adjustable arm  46 . The anchored arms  44  are fastened to the chair frame  12  by mechanical fasteners such as screws or bolts at the rear of the arm rest support surfaces  36  and  38  and inside the frame  12 . The adjustable arms  46  are received in slots in the rear lower portions of the arm rests  22  and  24  as shown in FIGS. 1 and 2. Mechanical fasteners secure the arm rests  22  and  24  to the adjustable arms  46 . Both ratchet assemblies  40  are inside components of the chair frame  12  and the arm rests  22  and  24  and are not seen in a complete chair  10 . The ratchet assembly  40  in the arm rest  22  is in the same position as the ratchet assembly in the arm rest  24 . The hinge and ratchet assembly  40 , adjacent to the arm rest support surface  36  and secured to the arm rest  22 , is not shown in FIG. 1 or  2 . 
     The ratchet assemblies  40  as shown in FIG. 6 have an anchor arm  44  and an adjustable arm  46 . The anchor arm  44  has four mounting bores  48  for fasteners that attach the anchor arm to the chair frame  12 . The adjustable arm  46  has three mounting bores  50  for attaching the arm rests  22  and  24  to the adjustable arms  46 . The adjustable arm  46  includes a series of ratchet teeth  52 . The number of teeth  52  is optional. However five teeth  52  as shown provides a down position and four raised positions and is believed to be satisfactory. The pivoted bolt  54  engages the teeth  52  to hold an arm rest  22  or  24  in a raised position. A spring  56  biases the pivoted bolt  54  toward the teeth  52 . An L-shaped bolt lockout  58  extends radially outward from the arm rest axis  42 . A short leg  60  of the bolt lockout  58  is adjacent to the ratchet teeth  52 . A bolt lockout pin  62  on the adjustable arm  46  engages the L-shaped bolt lockout  58  and forces the short leg  60  between the pivoted bolt  54  and the ratchet teeth  52 . A bolt lockout release pin  64  engages the L-shaped bolt lockout  58  and forces the short leg  60  from between the pivoted bolt  54  and the ratchet teeth  52  thereby freeing the bolt to be forced into engagement with a rack tooth  52  for the lower most position. A ratchet assembly cover  66  encases the pivoted bolt  54  and the L-shaped bolt lockout. 
     The ratchet assembly cover  66  of each of the hinge and ratchet assemblies  40  faces toward the right side of the lift chair  10  during use. The spring  56  biases the pivoted bolt in a counter clockwise direction as viewed from the right side when looking toward the left side. The adjustable arm  46  moves clockwise to a lowered position as seen from the right side. 
     During operation an arm rest  22  or  24  is lowered into contact with the arm rest support surface  36  or  38  and the bolt lockout release pin  64  moves the L-shaped bolt lockout out of engagement with the pivoted bolt  54 . FIG. 5 shows the adjustable arm  46  moving counter clockwise, the bolt lock release pin  64  engaging the L-shaped bolt lockout  58  and starting to move the bolt lockout out of locking engagement with the bolt. Note that the hinge and ratchet assembly is viewed from the left side in FIG.  5  and rotated 90° clockwise from the position shown in FIGS. 1 and 2. 
     Movement of the adjustable arm  46  counter clockwise about the axis of the hinge pin  70  causes the bolt lockout pin  62  to move the L-shaped bolt lockout  58  out of contact with the bolt  54 . As soon as the bolt lockout  58  disengages the bolt  54 , the spring  56  pivots the bolt  54  clockwise about the bolt pin  72  and into engagement with the teeth  52  as shown in FIG.  3 . In the position shown in FIG. 3, the arm rest  22  or  24  is in contact with an adjacent arm rest support surface  36  or  38 . 
     The arm rests  22  and  24  are raised manually from the positions shown in FIG. 1 to positions shown in FIG. 2 which will position the arm rests in a generally horizontal position when the chair frame  12  is pivoted about the axis  16  to a raised position as shown in FIG.  2 . With the arm rests  22  and  24  in the raised horizontal position, a challenged individual can make maximum use of his upper body and arms to rise to a standing position. 
     Movement of the forward ends of the arm rests  22  or  24  upward manually moves the adjustable arm  46  clockwise from the position shown in FIG. 3 toward the position shown in FIG.  4 . The points  74  of the ratchet teeth  52  cam the bolt  54  counter clockwise about the bolt pin  72 . The spring  56  forces the bolt  54  back into contact with each ratchet tooth  52 . An individual can stop raising the front of the arm rests  22  and  24  with the bolt  54  in contact with any chosen ratchet tooth  52 . Engagement between a tooth  52  and a pivoted bolt  54  prevents counter clockwise rotation of the adjustable arm  46  about the hinge pin  70  as shown in FIGS. 3 and 4. 
     The adjustable arm  46  is in a fully raised position in FIG.  4 . In this position the arm rests  22  and  24  provide surfaces that an individual can employ to raise to a standing position. In the raised position the arm rests  22  and  24  can assist a person to assume a sitting position. 
     The arm rests  22  and  24  are returned to the normal use position shown in FIG. 1 by moving the adjustable arm  46  clockwise from the position shown in FIG.  4 . The upward and rearward sloping surfaces  80  and  82  of the chair frame  12  provide space for the arm rests  22  and  24  to move upward and rearward from the position shown in FIG.  2 . This movement moves the adjustable arm  46  clockwise from the position shown in FIG.  4 . This clockwise movement of the adjustable arm  46  moves the bolt lockout release pin  64  into engagement with the L-shaped bolt lockout  58 , pivots the bolt lockout about the hinge pin  70  and moves the short leg  60  into a position in which the pivoted bolt  54  is held out of contact with the ratchet teeth  52  as shown in FIG.  5 . In this position the bolt  54  leaves the adjustable arm  46  free to move into the position shown in FIG.  3  and with the arm rests  22  and  24  in the position shown in FIG. 1 as described above. 
     The disclosed embodiment is representative of a presently preferred form of the invention, but is intended to be illustrative rather than definitive thereof. The invention is defined in the claims.