Abstract:
The present invention is directed to a powered actuation mechanism for a reclining chair. The powered drive mechanism rotates a drive link which engages a follower link to extend the leg rest assembly. A biasing mechanism is coupled to the leg rest assembly to retract the leg rest assembly. In this manner, the leg rest assembly cannot be fully retract when an obstruction with the leg rest assembly is encountered.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to reclining chairs, and more particularly to a power-assisted actuation mechanism for positioning a leg rest assembly between extended and retracted positions. 
     The integrated or “knock down” construction of a reclining chair utilizes unique fabrication and assembly techniques which effectively result in increased production efficiency and cost savings while concomitantly producing a high quality article of furniture. In general, the construction of these integrated reclining chairs is such that a pre-assembled actuation mechanism is integrated into pre-upholstered frame components which, when assembled, are rigidly interconnected to define a “box-like” chair frame. The pre-assembled actuation mechanism includes a drive rod and a front support shaft which are supported by and suspended between left and right side frame assemblies. Front and rear frame rail members interconnect the left and right side frame assemblies to define a “unitized” and rigid box-like chair frame. 
     There have also been recent developments in power-assisted chairs which include a motor-operated drive mechanism for permitting a seated occupant to actuate the leg rest assembly, to tilt the chair frame relative to the base assembly, and/or to recline the seat assembly between an upright and fully reclined position. Power-assisted chairs have, in the past, typically been targeted for very specific applications, such as to aid those persons needing assistance entering/exiting and operating the chair. In addition, persons not specifically needing assistance to operate the reclining chair find power features such as a power-assisted leg rest assembly to be a desirable convenience. Thus, there is a need for a reclining chair which combines the improved structure of a unibody chair frame with a power-assisted actuation mechanism, thereby providing a high-quality, affordable article of furniture. 
     SUMMARY OF THE INVENTION 
     In accordance with the principles of the present invention, a reclining chair having an actuation mechanism and a power-assisted drive mechanism is disclosed. The present invention provides a reclining chair having a motor-driven drive rod which can be simply and efficiently assembled so as to significantly reduce its overall complexity, weight, and cost, while providing improved operation and comfort. The present invention further provides a leg rest assembly operably coupled to the motor-driven drive rod when rotated in a first direction but which may be uncoupled from the motor-driven drive rod when rotated in a second direction. 
     In a preferred embodiment of the present invention, the reclining chair includes a pair of side assemblies interconnected at a rear portion by a rear frame rail and at a forward portion by a front frame rail. An actuation mechanism including a drive rod and a front support rod is suspended within the chair frame and operably coupled to a leg rest assembly having an pantograph linkage mechanism detachably coupled to the support shaft. The drive rod extends through a drive motor for selectively rotating the drive rod to extend the leg rest assembly. A pantograph linkage extends and retracts the leg rest in response to rotation of the drive rod by the drive motor. A drive link rotatably connected to the drive rod engages a follower link of the pantograph linkage to extend the leg rest assembly. A return spring mechanism is interconnected between the pantograph linkage and the chair frame for biasing the pantograph linkage towards the retracted position. The drive link is configured to disengage the follower link if retraction of the leg rest is obstructed, thereby uncoupling the pantograph linkage from the motor-driven drive rod. 
     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
         FIG. 1  is a partial exploded perspective view of a reclining chair incorporating the actuation mechanism of the present invention; 
         FIG. 2  is an assembled perspective view of the actuation mechanism shown in  FIG. 1 ; 
         FIG. 3  is a partially exploded perspective view of a portion of the actuation mechanism shown in  FIG. 2 ; 
         FIG. 4  is a detail of the drive link and follower link; 
         FIG. 5  is a side view illustrating a portion of the leg rest assembly in a retracted position; 
         FIG. 6  is a side view similar to  FIG. 5  illustrating the leg rest assembly in an extended position; and 
         FIG. 7  is a side view similar to  FIG. 5  illustrating the leg rest assembly in an obstructed state with the drive link disengaged from the follower link. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The following description of the preferred embodiment is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
     In accordance with the teaching of the present invention, an actuation mechanism for use in a reclining chair is disclosed. As used herein, the term “chair” is used broadly to encompass single and multi-person articles of furniture (i.e., chairs, sofas or loveseats). The present invention is readily adaptable to a “knock down” method of assembly in which the actuation mechanism is a pre-assembled and “integrated” component of the reclining chair. As presently preferred, all of the chair frame components are individually fabricated or subassembled to include the requisite brackets, springs, padding and upholstery in an “off line” batch-type basis. Subsequently, these preassembled frame components are modularly assembled for totally integrating the actuating mechanism therein. 
     The pre-assembled actuation mechanism is suspended from the chair frame components so as to provide precise mechanical alignment and superior structural rigidity while employing a highly efficient fabrication and assembly process. As presently preferred, the reclining chair may be capable of a variety of relative motions, namely independent recline of a seat back relative to a seat member, movement of a leg rest assembly between retracted and extended positions, and relative motion between the chair frame and the base assembly such as rocking, tilting, gliding and translating. Moreover, a full range of independent reclining movement of the seat back relative to the seat member is possible regardless of the operative position of the leg rest assembly between the retracted and extended positions. As used herein, the term “reclining” is used broadly to encompass any of such relative motions alone or in combination. 
     With particular reference now to the drawings, the functional and structural aspects of the present invention will now be described.  FIG. 1  illustrates the present invention incorporated into reclining rocking chair  10 . Reclining rocking chair  10  is substantially similar in function and structure to the chairs illustrated and disclosed in U.S. Pat. No. 5,806,921 issued on Sep. 15, 1998 which is commonly owned by the assignee of the present invention, and the disclosure of which is expressly incorporated by reference herein. Accordingly, only those aspects of reclining rocking chair  10  which relate to the present invention will be described in detail herein. A more detailed description of the mechanisms associated with this type of chair can be found in the above-identified United States patent incorporated by reference herein. 
     Chair  10  includes a chair frame assembly  12  and actuation mechanism  14  operatively suspended from chair frame assembly  12 . Chair frame assembly  12  includes side frame assemblies  16  interconnected at a rear edge by rear frame rail member  18  and interconnected at a front edge by front frame member assembly  20  to define a rigid “box-like” chair frame. Actuation mechanism  14  is preassembled to include drive rod  22  and front support shaft  24 , both of which are spatially oriented to be precisely located and suspended from side frame assembly  16 . Actuation mechanism  14  is shown to support leg rest assembly  26  thereon. More specifically, leg rest assembly  26  includes left and right pantograph linkages  30  both of which are operably associated with drive rod  22  and front support shaft  24  for retracting and extending leg rest board  28  in response to rotation of drive rod  22 . 
     A drive motor  32  is operably coupled to drive rod  22  to provide a motor-driven drive rod. As presently preferred, drive rod  22  is a one-piece element which extends through the gear set of drive motor  32  at the rearward portion of the drive motor  32 . One skilled in the art will recognize that the drive motor which is shown within the actuation mechanism  14  may be located at another position. In this regard, the drive motor  32  may be located outboard of the location shown. For example, the drive motor  32  may be located within a cavity of one of the side frame assemblies. The front portion of the drive motor  32  is supported by motor brace  34  extending downwardly from front support shaft  24 . The drive mechanism further includes motor control circuitry (not shown) to selectively operate the drive motor through the range of motion without overload thereof. A presently preferred drive motor is the subject of U.S. application Ser. No. 10/196,851, the disclosure of which is expressly incorporated by reference herein. 
     Left and right return spring mechanisms  36 , hereinafter referred to singularly, are interconnected between pantograph linkage  30  and rear frame rail member  18 . The return spring mechanism  36  includes a support bracket  38  extending from the rear frame rail member  18  and a spring member  40  interposed between the rear frame rail member  18  and the pantograph linkage  30 . As presently preferred, spring member  40  is a helical coil spring having a relatively high preload to maintain the leg rest assembly in a retracted position and a relatively low spring rate to minimize the retraction force. Tuning the spring member accordingly minimizes the counter force which the drive motor  32  must overcome to rotate the drive rod, while at the same time minimizes the retraction force imparted on an obstruction of the leg rest assembly. 
     The support bracket  38  has a hook portion  42  which extends through a slot  44  formed in the rear frame rail member  18  and captures the upper edge  46  thereof. Support bracket  38  is cantilevered from the chair frame  12  and extends downwardly and forwardly from the rear frame rail member  18  and terminates at end  46  which receives one end of spring member  40 . The bracket  38  is able to support the spring of the spring member  40  without fasteners securing it to the chair frame assembly  12 . As such, the position of the support bracket  38  relative to the rear frame rail  18  may be readily adjusted. A stud  50  (as shown in  FIG. 4 ) extends from pantograph linkage  30  and receives the other end of spring member  40 . Return spring mechanism  36  biases the follower link  64  rearwardly in a counterclockwise direction to urge the pantograph linkage  30  towards the retracted position. 
     Front frame member assembly  20  is a multi-piece assembly including front frame board  52  and a pair of front frame brackets  54  extending from opposite lateral ends of front frame board  52 . Spacer link  56  is interconnected between drive rod  22 , front support shaft  24  and frame board  52  to further integrate actuation mechanism  14  with chair frame assembly  12 . 
     As best seen in  FIGS. 2 and 3 , spacer link  56  includes a rear brace  58  generally supported on drive rod  22  which extends forwardly and upwardly towards the front support shaft  24 . Thus, the rear brace  58  of spacer link  56  is supported by drive rod  22 , while permitting relative rotation therein. Spacer link  56  also includes a front brace  60  that receives front support shaft  24  near the upper end thereof. Front brace  60  extends forwardly and upwardly from front support shaft  24  and is secured to front frame board  52  to provide cantilevered support for the drive rod  22  through the rear brace  58 . Front brace  60  and rear brace  58  of spacer link  56  are secured together with threaded fasteners  62 . 
     In this way, the front brace  60  and rear brace  58  may be separated to facilitate field service and replacement of the actuation mechanism without further requiring disassembly of the chair frame assembly  12 . Specifically, the drive rod  22  along with the drive motor  32  may be uncoupled and removed from the chair frame assembly  12  without requiring excessive disassembly of the unit. Specifically, the spring members  40  are uncoupled from the follower link  64 . Next, the various links—leg rest swing arm  74 , follower link  64  and rear brace  58 —are uncoupled from the drive rod  22 . Then, the rear brace is uncoupled from the front brace  60  by removing fasteners  62 . Lastly, the motor mount  34  is uncoupled from the drive motor  32 . At this point the drive rod  22  and drive motor  32  may be moved laterally relative to the remaining component of the chair and removed therefrom. Once the drive motor  32  has been serviced or replaced, the drive rod  22  and drive motor may be re-installed using the reverse sequence described above. 
     Right and left hand pantograph linkages  30  hereinafter referred to singularly, are operably suspended from drive rod  22  and front support shaft  24 . More specifically, pantograph linkage  30  includes a follower link  64  generally supported on the drive rod  22 . The follower link  64  is generally L-shaped having a transverse leg  66  extending generally parallel to drive rod  22  and a longitudinal leg  68  extending perpendicularly away from drive rod  22 . A pair of bushings  70  journally support the follower link  64  on the drive rod  22 . Thus, drive rod  22  is able to rotate relative to follower link  64 . 
     Similarly, pantograph linkage  30  is suspended from front support shaft  24  by leg rest swing bracket  72 . Leg rest swing bracket  72  receives front support shaft  24  and is releasably secured to leg rest swing arm  74 . Threaded fastener  76  releasably secures leg rest swing arm  74  with leg rest swing bracket  72 . In this way, the pantograph linkage  30  may be detached from the drive rod  22  and front support shaft  24  to facilitate field service and replacement thereof without further requiring disassembly of the chair frame assembly  14 . 
     Pantograph linkage  30  further includes support link  78  pivotally connected at pivot  80  to connection link  82 , which is pivotally connected at pivot  84  with front board link  86  which is in turn pivotally connected at pivot  88  with leg rest bracket  90 . Similarly, leg rest swing arm  74  is pivotally connected at pivot  92  to rear board link  94  which is, in turn, pivotally connected at pivot  96  to leg rest bracket  90 . Leg rest swing arm  74  is pivotally coupled at intermediate pivot  98  with support link  78 . Rear board link  94  is pivotally coupled at intermediate pivot  100  with connection link  82 . Follower link  64  is pivotally coupled at pivot  102  with support link  78 . In this manner, pantograph linkage  30  provides means for articulating the leg rest assembly between a retracted position as illustrated in  FIG. 5  to a fully extended position as illustrated in FIG.  6 . 
     Drive link  104  is supported on and rotates with drive rod  22 . Specifically, drive link  104  receives drive rod  22  and is rotatably coupled thereto. Nylon washer  106  is interposed between drive link  104  and bushing  70 . Transverse flange  108  extends laterally outwardly from drive link  104  and is adapted to engage the rearward edge  110  of follower link  64 . Accordingly, selective rotation of drive rod  22  in a counter-clockwise direction (as shown in  FIGS. 5-7 ) rotates drive link  104  causing transverse flange  108  to engage rear edge  110  of follower link  64 , thereby rotating follower link  64  in a counter-clockwise direction. Follower link  64  which acts through pivot  102  moves support link  78 . Such movement of support link  78  causes leg rest swing arm  74  to rotate about front support shaft  24  moving rear board link  94  outwardly and upwardly. In addition, the pivotally coupling of support link  78  with connection link  82  and front board link  86  results in coordinated upward and outward movement of front board link  86 . Extension of left and right hand pantograph linkages  30  is simultaneous to position the leg rest assembly from a stored or retracted position shown in  FIG. 5  to an extended or protracted position as shown in FIG.  6 . 
     As described herein, follower link  64  and drive link  104  function as a clutch mechanism for operably coupling the drive rod  22  with the pantograph linkage  30 . Specifically, the clutch mechanism operates in a driven mode for a first direction to couple the drive rod  22  and the pantograph linkage  30  for positioning the leg rest assembly  26  from a retracted position towards an extended position. The clutch mechanism operates in a free-wheeling mode for a second direction to uncouple the drive rod  22  and the pantograph linkage. 
     Counter rotation of the drive rod  22  in the clockwise direction (as shown in  FIGS. 5-7 ) rotates drive link  104  in a clockwise direction. The rearward biasing force generated by spring member  40  of return spring mechanism  36  rotates follower link  64  in a clockwise direction to maintain contact with transverse flange  108  of drive link  104 . In this manner, counter rotation of the drive rod  22  moves the pantograph linkage  30  towards the retracted position. Should the pantograph linkage  30  encounter an obstruction during counter rotation of drive rod  22 , counter rotation of follower link  64  stops and transverse flange  108  of the drive link  104  disengages follower link  64  to permit continued counter rotation of drive rod  22 . Further retraction of the pantograph linkage  30  is prevented since the follower link  64  and the leg rest swing arm  74  are journally supported on the actuation mechanism  14 . Once the obstruction is removed, follower link  64  counter rotates to engage drive link  104  and the leg rest assembly  26  may be fully retracted by the return spring mechanism  36 . In this manner, the motor-assisted drive rod  22  cannot power retract an obstructed leg rest assembly. 
     While the foregoing description of the preferred embodiment includes a motor-driven drive rod, one skilled in the art will recognize that a manually-operated drive rod could be employed with the present invention which prevents retraction of an unobstructed leg rest assembly. 
     The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.