Abstract:
A lift chair includes a chair frame, a stationary base section, and a motorized lift mechanism. Engagement of the motorized lift mechanism causes movement of a lift frame which is connected to the chair frame to cause movement from a first recumbent position to a second tilted position and allowing the user to be assisted to a standing position. Preferably, the chair can be rocked back and forth longitudinally, with the rocking motion being disabled while the lift mechanism is engaged. According to another preferred aspect, the chair can include a reclining back section which operates independently of the lift mechanism.

Description:
FIELD OF THE INVENTION 
     The invention relates to a improved lift chair that allows handicapped or other individuals to be assisted from an assumed initial sitting position to a substantially vertical or standing position and more particularly to a lift chair having rocking or gliding capability when the chair seat is in a recumbent position. 
     BACKGROUND OF THE INVENTION 
     It is often difficult, if not impossible at times, for handicapped or older individuals to assume a standing position from a recumbent position; that is, from a sitting posture. 
     To that end, a number of so-called “lift” chairs have been developed which assist seniors or handicapped individuals to achieve a standing position from the chair using a motorized mechanism to incline or otherwise move the chair seat. 
     In U.S. Pat. No. 5,641,201, issued to Casey et al., a free standing chair can be converted into a lift chair using a stationary base to which the chair is attached as well as a compact lift mechanism. The lift mechanism includes a motorized assembly mounted from the front of the chair to tilt the forward end thereof upon activation of the motor. 
     A desire in industry persists for lift chairs which incorporate other salient features found in conventional chair counterparts. Prior to the invention, for example, it has not been possible to provide a safe and reliable lift mechanism for a rocking or adjustable reclining chair. 
     SUMMARY OF THE INVENTION 
     It is a primary object of the present invention to overcome the above stated problems relating to lift chairs known in the art. 
     It is another primary object of the present invention to provide a lift chair which reliably allows the user to more easily assume a substantially vertical or standing orientation. 
     It is another primary object of the present invention to provide a lift chair which can be manufactured using a simple and reliable mechanism design. 
     It is a further primary object of the present invention to provide a lift mechanism for a rocking and/or reclining chair which is both safe and reliable. 
     Therefore and according to a preferred aspect of the present invention, there is provided a lift chair comprising: a chair frame portion, a stationary base portion disposed beneath the chair frame portion, and a motorized lift mechanism attached to the base portion which causes the seat of the chair to be moved between a first seated position and a second tilted position. 
     The motorized lift mechanism is supported at the rear of the stationary base section and engages the front of a movable lift frame so as to move the chair seat both upwardly and forwardly, thereby tilting the seat to permit the user to more easily assume a standing position from an initial recumbent position. 
     Moreover, and prior to initiation of the lift mechanism, the chair is capable of freely gliding or rocking back and forth longitudinally. After the lift mechanism has been engaged, however, the rocking mechanism of the chair is disabled to protect the user. 
     A feature of the present invention is the ability of the chair to reliably be raised and tilted forward from an initial recumbent position, thereby allowing the user to more easily assume a vertical orientation. 
     Another feature of the present invention is that the chair can be moved back and forth longitudinally in a gliding or rocking mode when the lift mechanism is not engaged, in which rocking motion is prevented automatically after the lift mechanism has been engaged by the user. 
     Another feature is that the chair seat back can be reclined independently of the stationary base or the lift frame of the chair. 
     An advantage of the chair is that the rocking motion can be disabled automatically upon activation of the lift mechanism, and enabled when the lift mechanism has returned the chair to a recumbent position. 
     These and other objects, features, and advantages will be apparent from the following Detailed Description which should be read in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front perspective view of a lift chair made in accordance with a preferred embodiment of the present invention; 
     FIG. 2 is a partial rear perspective view of the lift chair of FIG. 1; 
     FIG. 3 is a side elevational view of the lift chair of FIGS. 1 and 2 as depicted in an initial rest position; 
     FIG.  3 ( a ) is an enlarged view of the glide disabling mechanism of the lift chair of FIGS. 1-3; 
     FIG. 4 is a side elevational view of the lift chair of FIGS. 1-3 in a glide lock position; 
     FIG.  4 ( a ) is an enlarged view depicting the enablement of the glide disabling mechanism when the chair reaches the raised position of FIG. 4; and 
     FIG. 5 is a side elevational view of FIG. 3, showing the lift chair in a fully tilted position. 
    
    
     DETAILED DESCRIPTION 
     The following discussion relates to a lift chair made in accordance with a specific embodiment of the present invention. Throughout the course of discussion, several terms such as “top”, “lower”, “upper”, “bottom”, “transverse”, “lateral” and the like are frequently used. These terms are not intended to be limiting, but rather provide a frame of reference in regard to the accompanying drawings. 
     Referring now to FIGS. 1 and 2, a lift chair  10  is made in accordance with the preferred embodiment including a stationary base portion  12 , a chair frame portion  16 , and an interconnected lift mechanism  19 , the details of which will now be described in greater detail. 
     First, the stationary base portion  12  includes respective front and back pieces  20 ,  22 , each being interconnected by a spaced pair of parallel longitudinally extending cross pieces  24 , 26  which combine to define a rectangular configuration. Each of the above components of the stationary base portion  12  are preferably hollow tubular members made from steel or other suitable material which are welded or otherwise fastened together by known means. According to the present embodiment, each of the corners  30  on the bottom side  32  of the base section  12  include adjustable leveling guides  34  used by the user for leveling the chair  10 . 
     Still referring to FIGS. 1 and 2, the chair frame portion  16  includes a seat back  36  and a seat bottom  38  each consisting of a tubular frame having a number of spaced slats  39  used to retain cushioned sections (not shown). The seat back  36  and the seat bottom  38  are further attached to the rear leg  53  and front leg  54 , respectively, of a pair of parallel and vertically disposed arm supports  50  using threaded fasteners or the like which are inserted into respective pilot sections  51 ,  59 . The spacing between the arm supports  50  and the outer ends of the front and back pieces  20 ,  22  of the stationary base portion  12  define the overall width of the lift chair  10 . A stabilizer arm  52  interconnects each of the arm support legs  53 ,  54  while a back stabilizer bar  57 , only partially shown in FIG. 2, interconnects the parallel arm supports  50 . A pin  60  inwardly projects from each stabilizer arm  52 , the purpose of which is detailed in the operational description which follows below. Cushioned pad sections (not shown) are attached to a pair of longitudinal arm rests  62 , each rest spanning the top of the rear and front legs  53 ,  54  of the arm supports. 
     The seat bottom  38  of the chair frame portion  16  is inwardly angled as seen from front to back in this position, with the degree of incline being adjustable through a lever  94 , FIG. 2, adjacently disposed at the front of the chair  10  over a range defined by a slotted area  99 , FIG.  2 . Rotation of the lever  94  in the direction shown as  106 , FIG. 2, allows the seat bottom  36  and seat back  38  to slide along the slot  99  to effect reclining of the chair frame portion  16  independently of the lift frame  40  and stationary base portion  12 . 
     Still referring to FIGS. 1 and 2, the lift mechanism  19  of the invention includes a lift frame  40  and a motor drive assembly  46 . The lift frame  40  includes an articulating lever portion  44 , and an upper or top supporting portion  48 . The articulating lever portion  44  includes two pairs of spaced tubular leg members  58 ,  58 A. Each leg member pair  58 ,  58 A is pivotally attached using metal pins at a lower end  60  thereof to a rear support  62 , the rear support being welded or otherwise fixedly attached to the stationary base section  12  while upper ends  66  of the leg member pairs  58 ,  58 A are pivotally attached to the lower end of a front support  64 . Preferably, the front support  64  includes a plurality with separate aligned mounting holes  65  to allow additional tilt adjustment as described below. 
     The upper supporting portion  48  of the lift frame  40  is substantially rectangular in shape similar to that of the stationary base portion  12  and includes a pair of longitudinal sections  80  which are interconnected by a front section  84  and a rear stabilizing bar  85 . 
     The front supports  64  interconnect the articulating lever portion  44  and the lift frame  40 . More particularly, the upper end of each front support  64  is welded or otherwise fixedly attached to the front ends of the longitudinal sections  80  of the upper supporting portion  48 . A stopper  86  having a horizontal support surface  87  projects above the top surface of each rear support  62 , the function of which is clarified during the operational description which follows below. Finally, a pair of spaced transverse braces  68  spanning the width of the lift chair  10  interconnect each of the tubular leg member pairs  58 ,  58 A of the articulating lever portion  44 . 
     The motor drive assembly  46  of the lift mechanism  19  includes a motor support  88  provided in the center of the span of the top surface  15  of the rear piece  22  of the stationary base portion  12  which pivotally supports and retains a motor drive housing  55 , such as those sold by Okin Antriebstechnik, GmβH, among others. The motor drive assembly  46  includes a piston  96  pneumatically or otherwise driven by a contained motor (not shown) with the output end  98  of the piston extending from the housing toward the front of the chair  10  and more particularly to a piston support bracket  92  provided in the rear facing side  90  of the front section  84  of the upper supporting portion  48 . A hand-held remote control  95  is tethered by a control cable  97  to the motor drive housing  55 , the drive assembly being powered through an external power supply (not shown) via a power cable  56  (only partially shown in FIG.  2 ). Details relating to the motor drive assembly  46  are commonly known in the field and require no further discussion except as needed to explain features of the invention. 
     As previously noted, the front supports  64  of the lift frame  40  interconnect the upper supporting portion  48  with the articulating lever portion  44 . Furthermore, the chair frame portion  19  is pivotally interconnected to the upper supporting portion  48  of the lift frame  40  utilizing two spaced pairs of swings or pivot arms; namely, a front pair  100  and a rear pair  102 . Each of the front and back swings  100 ,  102  are similarly constructed thin plate-like members which downwardly extend from exterior sides  82  of the longitudinal sections  80  of the upper supporting portion  48 . More particularly and according to this embodiment, formed cylindrical pilot sections  83  projecting from the exterior sides  82  of the longitudinal sections  80  each include a center opening for receiving a threaded fastener aligned with a similarly sized opening in the upper ends of each of the swings  100 ,  102  while a similar pivoting connection is provided at the lower ends of each swing through a pilot section extending from the inward facing surface at the bottom of each of the front and rear legs  54 ,  53  of the arm supports  50  of the chair frame portion  16 . More particularly, a bolt or other fastener is mounted through a metal bushing, the end of the bolt being secured by a pushnut. Each pair of swings  100 ,  102  is interconnected by a traverse axle  89  adjacent the upper ends thereof. 
     The above pivotal connections of the swings  100 ,  102  permits longitudinal rocking movement of the entire chair frame portion  16  relative to the fixed upper supporting portion  48  of the lift frame  40  while the lift chair  10  is in a normal rest position, FIG. 3, and prior to actuation of the lift mechanism. 
     Finally, and referring in part to FIGS.  2  and  3 ( a ), a glide disabling mechanism is provided in the form of planar glide locking bars  110  attached to the exterior sides  82  of the longitudinal sections  80  of the upper supporting portion  48  between the pairs of swings  100 ,  102 . The glide locking bars  110  are mounted to a respective exterior side  112  using a threaded fastener mounted through a center mounting hole disposed directly between a pair of spaced slots  116 . A front end  120  of each glide locking bar  110  is connected to one end  122  of a tensioning spring  124  with the remaining end  126  of the spring being attached to a pin  128  outwardly extending from the exterior side  82  of the longitudinal sections  80  of the upper supporting section  48  of the lift frame  40 . Each glide locking bar  1   10  includes a pair of spaced slots  116  formed in a top surface  118 , the function of which is described in greater detail in the operational description below. 
     The operation of the herein described lift chair  10  will now be described with reference to FIGS. 3-5. Initially and prior to activation of the lift mechanism  19 , as shown in FIGS.  3  and  3 ( a ), the chair  10  is substantially horizontally disposed in a rest position with the chair frame portion  19  being freely able to glide back and forth longitudinally based on the pivotable connection of the front and rear swings  100 , 102  to the chair frame portion  16 . In this depicted position, the lower pivoting legs  58 A of the articulated lever portion  44  are substantially parallel with the top surface  15  of the stationary base portion  12 , while the upper supporting portion  48  is also parallel to the base portion. The lower end of the front support  64  is in contact with the top surface  15  of the stationary base portion  12  while the rearmost end of each of the glide locking bars  112  and the longitudinal sections  80  of the upper supporting portion  48  are in direct contact with the horizontal support surface  87  of the stoppers  86 . Tilt adjustments can also be made through selecting of one of the plurality of mounting holes  65  and removing a pin  76  attached to a through fastener  78  on either front support  64  to adjust the position of the lever legs  58 A, as shown in FIGS. 1 and 5. 
     Depression of an UP button (not shown) on the remote control  95  initiates the motor drive assembly  46  and begins the lifting process which is herein sequentially described. 
     Actuation of the motor drive assembly  46  initially causes an outward extension of the piston  96  toward the front of the chair  10 . As noted previously, the motor drive assembly  46  is pivotally but fixedly attached to the rear transverse piece  28  of the stationary base portion  12  via support  88 . Therefore, the outward extension of the output end  98  of the piston  96  pushes against the center of the front section  84  of the upper supporting portion  48  through the support bracket  92 . Because the piston  96  is obliquely attached to the front section  84 , the initial slight forward extension thereof causes each of the glide locking bars  110  to lift slightly away from the horizontal support surface  87  of the stoppers  86  and moves the glide locking bars  110  upwardly due to the biasing of the tensioning spring  124  at the front end thereof such that the pin  60  inwardly extending from the stabilizer arm  52  of each of the vertical arm supports  50  of the chair frame portion  16  is brought into engagement with the top surface  118  of each glide locking bar  110 . As the piston  96  continues to move forward, the front of the lift frame  40  is caused to pivot downwardly while the rear half thereof moves upwardly and forwardly. 
     As shown in FIG.  4 ( a ), the above movement of the lift frame  40  continues until the inwardly directed pin  60  moves downwardly along the top surface  118  of the glide locking bars  110  and drops into locking engagement into one of the slots  116 , the chair now being in a “glide locked” position. In this position, and as apparent from FIGS. 4 and 5, the chair frame portion  16  is fully immobilized with respect to the lift frame  40 , with the swings  100 ,  102  being interconnected by transverse axle members  89 . Any additional movement of the chair  10  thereafter requires the chair frame portion  16  and the lift frame  40  be moved in tandem. 
     As shown in FIG. 5, additional forward movement of the lift frame  40  due to the pushing force of the piston  96  continues with the upper supporting portion  48  being tilted forward based on the pivoting connection of the articulating arms  58 ,  58 A with the front support  64 . Continued outward movement of the piston  96  causes the front support  64  to lift away from the top surface  15  of the stationary base section  12  and pivot in a clockwise direction with the upper end of the front support being caused to tip forward. In the meantime, the connected leg pairs  58 ,  58 A of the articulated lever portion  44  are also caused to pivot and lift upwardly to the position shown. 
     As a result, the upper supporting section  48  translates forwardly relative to the front and rear pieces  20 ,  22  of the stationary base section  20  with the front end of the upper support section  48  moving downwardly causing a forward tilt of the chair frame portion  16  as compared with the initial recumbent position of FIG.  3 . The user is then able to more easily remove himself or herself from the chair  10 . 
     Pressing the DOWN button (not shown) of the remote control  95  reverses the above sequence. That is, the piston  96  is retracted by the motor drive assembly  46 , causing the upper portion of the lift frame  40  to be pulled toward the rear of the stationary base portion  20 . As this movement commences, the front end of the upper supporting section  48  begins to drop with the movement of the chair frame portion  16  still being controlled only by the retraction of the piston  96 . The front support  84  pivots in a counterclockwise direction as the articulating arms  58 ,  58 A begin to rotate in a clockwise sense toward the stationary base portion  12  with the lower end of the front support  64  eventually engaging the top surface  15  thereof. The upper supporting portion  48  moves to an essentially horizontal attitude during the movement. 
     As the rear surface of the upper supporting portion  48  engages the horizontal support surface  87  of the projecting stoppers  86 , the rearmost ends of the glide locking bars  110  are caused to pivot based on their connection to the tensioning spring  124 , releasing the pin  60  from the slot  116  and thereby releasing the chair frame portion  16  from the lift mechanism  19  and permitting rocking or gliding movement to resume. 
     PARTS LIST FOR FIGS. 1-5 
       10  lift chair 
       12  stationary base portion 
       15  top surface (base) 
       16  chair frame portion 
       19  lift mechanism 
       20  front piece 
       22  back piece 
       24  cross pieces 
       26  cross piece 
       30  corners 
       32  bottom side 
       34  leveling guides 
       36  seat back 
       38  seat bottom 
       39  slats 
       40  lift frame 
       44  articulating lever portion 
       46  motor drive assembly 
       48  upper supporting portion 
       50  arm supports 
       51  pilot section 
       52  stabilizer arm 
       53  rear leg 
       54  front leg 
       55  motor drive housing 
       56  power cable 
       57  back stabilizer bar 
       58  tubular leg members 
       59  pilot section 
       61  threaded fastener 
       62  longitudinal arm rests 
       64  front supports 
       65  mounting holes 
       66  upper ends 
       68  braces 
       70  rear supports 
       76  pin 
       78  fastener 
       80  longitudinal sections 
       82  exterior sides 
       83  pilot section 
       84  front section 
       85  pilot section 
       88  motor support 
       89  transverse axle members 
       90  rear facing side 
       92  support 
       94  canting lever 
       95  remote control 
       96  piston 
       97  control cable 
       98  output end 
       99  slot 
       100  front swings or pivot arms 
       102  rear swings or pivot arms 
       104  mounting holes 
       110  glide locking bars 
       112  exterior sides 
       114  side pieces 
       116  slots 
       118  top surface 
       120  front end 
       122  spring end 
       124  tensioning spring 
       126  spring end 
       128  pin 
     Though the preceding has been described in terms of a preferred embodiment, it will be readily apparent that modifications and variations are possible within the scope of the invention as defined by the following claims.