Abstract:
A three-position leg rest mechanism includes a link and sector members rotatably supported to the link. The sector members are coupled to a drive rod for rotation therewith. A biased pin engages the sector members and releasably locks with the sector members in each of three positions. A locking link end opposite the sector members is coupled to a support shaft of the actuation mechanism. An elastically compressible member is positioned between the sector members which is partially compressed by the pin as the pin moves relative to the sector members, reducing contact noise between the pin and the sector members.

Description:
FIELD OF THE INVENTION 
     The present invention relates in general to furniture members and more specifically to a device and method for operating a furniture member leg rest. 
     BACKGROUND OF THE INVENTION 
     Traditionally, furniture members such as reclining chairs are equipped with an actuation mechanism which is operatively interconnected between a prefabricated chair frame and a stationary base assembly. The actuation mechanism is typically a combination of various mechanical linkages operable for providing various comfort features such as independent reclining movement of a seat assembly as well as actuation of an extensible leg rest assembly and associated tilting of the chair frame. 
     While many conventional reclining chairs operate satisfactorily, furniture manufacturers are continually striving to develop improved frames and actuation mechanisms for reducing system complexity and smoothness of operation as well as occupant comfort. Furthermore, there is a continuing desire to develop improved fabrication and assembly techniques which will result in reduced costs while promoting increased efficiency and improved product quality. 
     In conventional actuation mechanisms, a lubricant is commonly used to reduce friction between mechanism components. Due to the limited accessibility of the mechanism components after installation and during subsequent consumer use, continued application of the lubricant is difficult to ensure. Increased mechanism noise and undue wear can therefore result. Components that require no lubrication are therefore desirable. 
     SUMMARY OF THE INVENTION 
     According to one preferred aspect for a multiple position leg rest mechanism of the present invention, an actuation mechanism includes a drive rod and a front support shaft. A leg rest mechanism for releasably positioning a leg rest in each of a retracted position, an extended position, and at least one intermediate position, the leg rest mechanism includes a pair of sector plates coupled to the drive rod for co-rotation therewith. Each of the sector plates has a peripheral edge. An elastically compressible element is interposed between the sector plates. A biased pin slidably engages the peripheral edge of the sector plates. A biasing element biases the pin into engagement with the peripheral edge. The pin partially elastically compresses the compressible element during engagement of the pin with the peripheral edge of the sector plates. 
     According to another aspect of the invention, a furniture member leg rest mechanism includes a rotatable, rectangular-shaped drive rod. A leg rest assembly is coupled to the drive rod for extension by rotation of the drive rod. A spring assisted toggle assembly biases the leg rest assembly in each of a retracted position and a fully extended position. A pair of sector plates couple to the drive rod for co-rotation therewith, each of the sector plates having a peripheral edge including at least one recess. An elastically compressible element is interposed between the sector plates and extends beyond the peripheral edge of the sector plates. A pin extends through the sector plates and slidably engages the peripheral edge of the sector plates. A biasing element biases the pin into engagement within the recess created in the peripheral edge. The pin elastically compresses the compressible element during engagement of the pin with the peripheral edge of the sector plates. 
     According to still another aspect, a method for operating a furniture member leg rest mechanism includes interposing the compressible element between the sector plates. The sector plates and the compressible element are coupled to the drive rod for co-rotation therewith. The pin is biased into engagement with the peripheral edge using the biasing element. The drive rod is rotated. The pin is slidably engaged with the peripheral edge of the sector plates to elastically compress the compressible element. 
     A multiple position leg rest mechanism of the present invention provides several advantages. By positioning a compressible material element between sector plates that control a leg rest assembly rotation position, a pin engages the compressible material element and limits the noise generated when locked positions of the mechanism are reached. The compressible material element also eliminates a need for lubricant which would be required if the pin and the sector plates are both made of metal. The sector plates can also be made of a polymeric material, further reducing the noise of the mechanism. Biasing elements ensure the pin continuously contacts the peripheral edge of the sector plates, which also therefore ensure the pin engages in recesses of the sector plates positioned to provide locked positions of a leg rest assembly. 
     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 several preferred aspects 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 perspective view of a chair having a multiple leg rest position mechanism of the present invention; 
         FIG. 2  is an exploded perspective assembly view of the frame and mechanism components for chair of  FIG. 1 ; 
         FIG. 3  is a cross sectional side elevational view taken at section  3 - 3  of  FIG. 2 ; 
         FIG. 4  is an exploded perspective assembly view of a detent mechanism of the present invention; 
         FIG. 5  is a side elevational view of an assembled detent mechanism of the present invention; 
         FIG. 6  is a top plan view of the detent mechanism of  FIG. 5 ; 
         FIG. 7  is a side elevational view of a leg rest stowed rotational stop position of the detent mechanism of  FIG. 5 ; 
         FIG. 8  is a top plan view of the detent mechanism of  FIG. 7 ; 
         FIG. 9  is a cross sectional side elevational view of the detent mechanism taken at section  9 - 9  of  FIG. 6 ; 
         FIG. 10  is a cross sectional side elevational view of the detent mechanism in a first rotational stop position; 
         FIG. 11  is a cross sectional side elevational view of the detent mechanism in a second rotational stop position; and 
         FIG. 12  is a cross sectional side elevational view of the detent mechanism in a third or fully extended rotational stop position. 
     
    
    
     DETAILED DESCRIPTION 
     The following description of several aspects of the invention is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
     In accordance with the teachings of the present invention, a multiple position leg rest mechanism for use in single and multi-person articles of furniture (i.e.: chairs, sofas and/or loveseats) is disclosed. A general understanding of the art to which the present invention pertains is disclosed in U.S. Pat. No. 3,325,210, Adjustable Leg Rest Locking Device, U.S. Pat. No. 5,570,927, Modular Wall Proximity Reclining Chair, and U.S. Pat. No. 6,655,732, Multiple Position Leg Rest Mechanism For A Reclining Chair, which are commonly owned by the assignee of the present invention and the disclosure of which is expressly incorporated by reference herein. As will be described, the pre-assembled actuation mechanism is uniquely suspended in a “fixed” pivot-point arrangement from pre-upholstered box-like frame components so as to provide precise mechanical alignment and superior structural rigidity while concomitantly facilitating application of highly efficient fabrication and assembly processes. 
     With reference to  FIG. 1 , the article of furniture shown is a combination wall proximity recliner and tilt chair, hereinafter referred to as chair  10 . Chair  10  includes an actuation mechanism  12  and various upholstered frame components that can be quickly and simply assembled as a modular seating unit. It should also be understood, however, that the elements of actuation mechanism  12  are not limited to use with chair  10 , but are applicable for use in virtually any type of single or multi-person article of furniture. As such, the particular structure of the various sub-assemblies and components which, when assembled, define chair  10  are merely intended to illustrate but one furniture application to which the present invention is applicable. 
     As further shown in reference to  FIG. 1 , a seat back  14  can be rotated with respect to a seat support assembly  15 . A leg rest assembly  16  is extensible in an arc A from a stowed position abutting chair  10  to an extended position using a hand lever  18 . In one aspect of the invention, hand lever  18  is rotated counterclockwise about an arc B to extend leg rest assembly  16 , and rotated clockwise about an arc B′ to return leg rest assembly  16  from the extended to the stowed position. 
     Referring now generally to  FIG. 2 , the various frame components are shown in exploded view with upholstery, padding, springs, etc. removed to better illustrate the interdependency of the frame components construction which can be rapidly and rigidly assembled in a relative easy and efficient manner. As such, all of the frame components can be individually fabricated or sub-assembled to include the requisite brackets, springs, padding and upholstery on an “off-line” batch-type basis. Thereafter, the various pre-assembled and upholstered frame components are assembled for totally integrating actuation mechanism  12  therein. 
     As best seen in  FIG. 2 , actuation mechanism  12  is integrated into and operably suspended from a chair frame  20  and, in particular, from left and right side frame assemblies  22 ,  24 . In addition to side frame assemblies  22 ,  24 , chair frame  20  also includes a front rail assembly  26  and a rear rail  28  which, when interconnected, connect to a rigid “box-like” chair frame  29 . In general, the structural frame components such as side frame assemblies  22 ,  24 , front rail assembly  26 , and rear rail  28 , are each constructed in a manner which enables them to support springs, padding, upholstery, and the like in order to complete a decorative and stylish chair  10 . Each frame component is individually preassembled for subsequent modular assembly into chair  10 . However, it is to be understood that the specific construction shown for each frame component is merely exemplary in nature. 
     With reference to  FIGS. 2 and 3 , actuation mechanism  12  includes a drive rod  30  and front support shaft  32 , both of which are spatially oriented to be located and “suspended” from left and right side frame assemblies  22 ,  24 . In some aspects, drive rod  30  is an elongated square-shaped metal shaft having manually-operable hand lever  18  (shown in  FIG. 1 ) secured thereto adjacent an upholstered exterior portion of one of side frame assemblies  22  or  24 . Hand lever  18  can therefore be easily reached by a person seated in chair  10  for convenient actuation of drive rod  30 . Leg rest assembly  16  as shown in  FIG. 1  is supported for extensible movement using actuation mechanism  12 . More specifically, leg rest assembly  16  includes a left and a right pantograph linkage  34 ,  36  and a spring-assisted toggle assembly  38  which are operably associated with drive rod  30  and front support shaft  32  for permitting the seat occupant to selectively actuate leg rest assembly  16  in response to rotation of drive rod  30  via hand lever  18 . 
     Leg rest assembly  16  is both supported and moved by left and right hand pantograph linkages  34 ,  36 . In some aspects of the invention, left and right hand pantograph linkages  34 ,  36  are identical. Pantograph linkages  34 ,  36  are operably suspended about a set of “fixed” suspension points defined by front support shaft  32 . The extensible action of leg rest assembly  16  takes place simultaneously for both the left hand and right hand pantograph linkages  34 ,  36  when there is sufficient angular rotation of drive rod  30  via hand lever  18 . With specific reference to  FIG. 3 , an exemplary construction for a spring-assisted toggle assembly  38  is shown which works coactively with leg rest pantograph linkages  34 ,  36  for biasing and securely holding leg rest assembly  16  in the fully retracted or stowed position against front rail assembly  26 . Toggle assembly  38  also provides a biasing element  39  such as a spring operable to create a biasing force for biasingly urging leg rest assembly  16  toward any of its extended positions. 
     According to the representative aspect shown in  FIGS. 4 and 5 , a ratchet  40  and a pawl assembly  41  allow chair  10  to be locked in a plurality of reclined/tilted positions. A detent mechanism  42  is also provided to interconnect drive rod  30  and front support shaft  32  for providing various “locked positions” for leg rest assembly  16  between its “stowed” (or retracted) and its “extended” positions. Generally, detent mechanism  42  provides a stowed position and three distinct locking positions for leg rest assembly  16  that are established independent of the reclined/tilted position of seat back  14  or seat support assembly  15  of chair  10 . Locking positions as defined herein refer to individual, releasable positions of leg rest assembly  16  which are temporarily provided by detent mechanism  42  and retained until acted on such as by rotating hand lever  18  to change to another position. 
     With continuing reference to  FIGS. 4 through 5 , detent mechanism  42  includes a sector assembly  44  having a square-shaped aperture  45  formed therethrough which slidably receives drive rod  30  and rotates in response to rotation of drive rod  30 . An incline link  46  extends generally between sector assembly  44  and a link connector  47 . Link connector  47  is rotatably pinned by a U-shaped pin  48  through apertures at a first end  49  of incline link  46 . Connection between link connector  47  and support shaft  32  is made by sliding support shaft  32  through an aperture  50  created through a second end  51  of link connector  47 . 
     Sector assembly  44  includes a pair of sector plates  52 ,  53  each having an arcuate peripheral edge  54 . In one aspect, sector plates  52 ,  53  are also provided of a polymeric or composite material. In another aspect, sector plates  52 ,  53  are created of a metal material such as steel or aluminum. Sector assembly  44  further includes a compressible element  56  interposed between the pair of sector plates  52 ,  53 . In one aspect, compressible element  56  is provided of a polymeric or rubber material. A pivot pin  58  extends sequentially through: an aperture  60  created in sector plate  52 ; an aperture  62  of a first extending leg  64  of incline link  46 ; an aperture (not visible) in compressible element  56 ; another aperture (not visible) in a second extending leg  66  of incline link  46 ; and another aperture  60  created in sector plate  53 . Sector assembly  44  is slidably positioned on drive rod  30  and pinned in place using a fastener  68  such as a expandable pin pressed through an aperture  70  of compressible element  56  and one of a plurality of receiving apertures  72  created in drive rod  30 . 
     A pin  74  is slidably received in an L-shaped aperture  76  created in each of first and second extending legs  64  and  66 . Pin  74  engages each of a plurality of cam areas  78  created on sector plates  52 ,  53  and compressible element  56 . Pin  74  is biased toward pivot pin  58  using a pair of biasing elements  80 ,  81  such as extension springs seated in rings  82  created proximate to ends of each of pivot pin  58  and pin  74 . 
     Referring now to  FIGS. 5A and 5B , the cam areas of each of sector plates  52 ,  53  and compressible element  56  created in arcuate peripheral edge  54  define a first cam  84 , a pair of locking recesses  86 ,  88 , a second cam  90 . The stowed position of actuation mechanism  12  is represented in  FIGS. 5A and 5B . As sector assembly  44  rotates from the stowed position shown, pin  74  releases from temporary contact with first cam  84  and can temporarily releasably engage in each of locking recesses  86 ,  88  to establish first and second temporary locking positions of leg rest assembly  16 . Further rotation of sector assembly  44  releases pin  74  from locking recess  88  and a fully extended position of leg rest assembly  16  is reached when pin  74  releasably engages second cam  90 . A fixed spacing C is provided between drive rod  30  and support shaft  32 . Rotation of sector assembly  44  therefore requires angular displacement of both incline link  46  and link connector  47  relative to a rotational axis or longitudinal centerline of pivot pin  58 . Pin  74  is also permitted by biasing elements  80 ,  81  to follow the contour of cam areas  78  as sector assembly  44  rotates in an arc D in response to rotation of drive rod  30 . 
     The use of polymeric material for each of sector plates  52 ,  53  and compressible element  56  reduces a “ratcheting noise” as pin  74  engages each of locking recesses  86 ,  88 , or second cam  90 . It is desirable if sector plates  52 ,  53  are provided of a non-polymeric or non-rubber material that compressible element  56  extend outwardly beyond peripheral edge  54 , forming a standout portion  91 , to permit compressible element  56  to absorb the contact force as pin  74  engages locking recesses  86 ,  88 , or second cam  90  of sector plates  52 ,  53 . 
     As best seen in reference to  FIGS. 6 through 9 , when assembled, incline link  46  is supported for rotation about pivot pin  58  on an axis of rotation  92  through sector assembly  44 . Biasing elements  80 ,  81  bias pin  74  toward pivot pin  58  in direction E. Pin  74  is in contact with first cam  84  and is substantially positioned within a first leg  94  of L-shaped aperture  76 . Further rotation of sector assembly  44  about an arc F is prevented by the combination of first leg  94  and first cam  84 . Contact with compressible element  56  advantageously reduces friction between pin  74  and peripheral edge  54 , which eliminates the need for a lubricant between pin  74  and peripheral edge  54 . A clearance opening  96  between incline link  46  and link connector  47  allows rotation of incline link  46  relative to link connector  47  about U-shaped pin  48 . An aperture  98  through drive rod  30  is clearly visible in  FIG. 9  for receiving fastener  68 . 
     Referring generally to  FIG. 10 , as hand lever  18  is manually rotated in the direction of arc B, drive rod  30  and sector assembly  44  rotate to initiate extension of leg rest assembly  16  from the retracted position to the first locking position shown. Rotation of sector assembly  44  results in rotation of incline link  46  about pivot pin  58 . Pin  74  is released from contact with first cam  84  and translates about peripheral edge  54  of sector plates  52 ,  53  and compressible element  56 . When locking recess  86  is encountered, biasing elements  80 ,  81  bias pin  74  into seating engagement within locking recess  86 . Pin  74  is temporarily “locked” within locking recess  86 , increasing the resistance to further rotation of drive rod  30 . At locking recess  86 , leg rest assembly  16  is positioned in a first position which is approximately one-third extended. The compressive resistance provided by the relatively softer material of compressible element  56  compared to a metal material of pin  74  reduces a ratcheting sound as pin  74  engages within locking recess  86 . Incline link  46  and link connector  47  rotate approximately 40 degrees relative to each other between the stowed position of  FIG. 5A  and the first locked position of  FIG. 10 . Pin  74  is maintained within first leg  94  of L-shaped aperture  76  during the transition between the stowed and first lock positions. 
     Referring next to  FIG. 11 , the leverage produced by rotation of hand lever  18  to rotate drive rod  30  is necessary to ratchet pin  74  out of locking recess  86 . The biasing force of biasing elements  80 ,  81  do not significantly affect the leverage required to rotate drive rod  30  and is easily overcome. Pin  74  ratchets out of locking recess  86  and rotates due to contact with compressible element  56  as it travels about peripheral edge  54 . Compressible element  56  provides sufficient friction to induce rotation of pin  74  which prevents metal on metal sliding between pin  74  and peripheral edge  54 . Pin  74  does not significantly elastically deflect compressible element  56  as pin  74  travels about peripheral edge  54 . When the next locking recess, locking recess  88  is encountered, biasing elements  80 ,  81  provide sufficient bias force to bias pin  74  to seat within locking recess  88 . Pin  74  is temporarily “locked” within locking recess  88 , locking recess  88  increasing the resistance to rotation of drive rod  30 . At locking recess  88 , leg rest assembly  16  is positioned in an intermediate position which is approximately two-thirds extended. Similar to entry into locking recess  86 , the softer material of compressible element  56  extending into locking recess  88  reduces a ratcheting sound as pin  74  ratchets into and engages within locking recess  88 . 
     Referring now to  FIG. 12 , after further overcoming the biasing force of biasing elements  80 ,  81 , still further rotation of drive rod  30  translates pin  74  out of locking recess  88 . Translation of pin  74  continues until pin  74  engages second cam  90 . When pin  74  engages second cam  90 , leg rest assembly  16  is positioned in a third or fully extended position. In the fully extended position, second cam  90  urges pin  74  forwardly and upwardly (as viewed in  FIG. 12 ) into a second leg  100  of L-shaped aperture  76 . In this manner, pin  74  disengages from peripheral edge  54  of sector plates  52 ,  53  such that counter-rotation of drive rod  30  in rotation direction arc B′ is not inhibited by pin  74  engaging locking recesses  86  or  88  of peripheral edge  54 . From any of the first or second intermediate positions of leg rest assembly  16 , or the fully extended position shown, subsequent clockwise rotation about arc B′ of hand lever  18  and drive rod  30  acts to return leg rest assembly  16  towards the fully retracted position. As leg rest assembly  16  returns toward the fully retracted position, sector assembly  44  rotates relative to incline link  46 , and pin  74  engages first cam  84  to reset the pin  74  position into first leg  94 . Biasing elements  80 ,  81  urge pin  74  into re-engagement within the first leg  94  of L-shaped aperture  76 . In this manner, detent mechanism  42  is reset. 
     According to one preferred embodiment of the invention, compressible element  56  is a rubber material having approximately an 80 durometer hardness. In alternate embodiments, compressible element  56  is a silicon rubber or a polymeric material such as nylon, or the like. Compressible element  56  is provided from elastically compressible material to provide at least two functional improvements. A first improvement is the elimination of the need for a lubricant between pin  74  and sector plates  52 ,  53 . This eliminates cost and time of a lubrication manufacturing step and precludes the possibility of loss of lubricant occurring during later use of chair  10 . A second improvement is the noise reduction achieved using a compressible material between pin  74  and the metal material of pin  74 , particularly proximate to locking recesses  86  and  88 . The overall sound level generated during operation of chair  10  due to actuation mechanism  12  is therefore reduced. 
     Compressible element  56  can also be extended beyond peripheral edge  54  of each sector plate  52 ,  53  by an extension dimension of approximately 0.15 cm (0.06 in). The extension dimension is normally provided in each of recesses  86  and  88 . The value of the extension dimension can vary at the discretion of the designer and is based on the compressibility of the material selected for compressible element  56 . The extension dimension is beneficial if the material of sector plates  52 ,  53  are metal, which could prevent rotation of pin  74  or induce a ratcheting noise when pin  74  engages within locking recess  86  or  88 . 
     A multiple position leg rest mechanism of the present invention provides several advantages. By positioning a compressible material element between sector plates that control a leg rest assembly rotation position, a pin engages the compressible material element and limits the noise generated when locked positions of the mechanism are reached. The compressible material element also eliminates a need for lubricant which would be required if the pin and the sector plates are both made of metal. The sector plates can also be made of a polymeric material, further reducing the noise of the mechanism. Biasing elements ensure the pin continuously contacts the peripheral edge of the sector plates, which also therefore ensure the pin engages in recesses of the sector plates positioned to provide locked positions of a 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.