Abstract:
A rocking chair including a body supporting portion, a chair base portion, a locking assembly arid a linkage. The linkage includes a strip of resilient material extending across the backrest of the chair, positioned to receive the back of an occupant of the chair. The strip has a resiliency such that, when an occupant leans back against the backrest of the chair, the strip is responsive to the pressure applied directly thereto to deform rearwardly from an original position and, when the pressure ceases, the strip returns to its original position. The linkage is operatively connected to the locking assembly to cause the locking assembly to prevent movement of the body supporting portion relative to the chair base portion when the strip is in the original position, and to cause the locking assembly to allow movement of the body supporting portion relative to the chair base portion when the strip is deformed rearwardly from the original position.

Description:
CROSS-REFERENCES TO RELATED APPLICATION 
     This application is a divisional application of U.S. patent application Ser. No. 09/927,821, filed Aug. 10, 2001, which is a continuation-in-part of U.S. patent application Ser. No. 09/518,886, filed Mar. 6, 2000, now U.S. Pat. No. 6,402,242. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to the art of manufacturing chairs and, more particularly, to a novel locking assembly for rocking chairs. The locking assembly is characterized by its ability to lock the body portion of the chair relative to the base portion of the chair in a selected position. 
     BACKGROUND OF THE INVENTION 
     A typical rocking chair includes a body supporting structure that is mounted on a chair base by a rocking assembly. The prior art has recognised that it is desirable to provide rocking chairs with a locking mechanism that allows retaining the body-supporting portion of the chair in a certain position with relation to the base. This is useful in instances where the occupant of the chair wishes to negate at least temporarily the rocking function of the chair. 
     One locking mechanism that is known in the art comprises two components, namely a rack element including a plurality of fingers in a spaced apart relationship, and a pin element that can fit between selected fingers of the rack. The rack element is mounted to the body-supporting portion of the chair while the pin is mounted to the chair base portion. The rack element is also provided with a linkage that allows moving the rack in and out of engagement with the pin. In use, when the occupant of the chair desires to lock the chair in a certain position, he or she operates the linkage to bring the rack in engagement with the pin such that the pin enters the fingers that correspond to the selected position in which the chair is to be immobilized. To release the lock, it suffices to operate the linkage in the opposite direction and thus disengage the rack from the pin. 
     This type of locking mechanism is not entirely satisfactory for a number of reasons. One of its drawbacks relates to the smoothness of operation. For instance, the rack will engage with the pin only when the inter-pin space is precisely aligned with the pin. In a situation when the occupant of the chair attempts to engage the locking mechanism in a position such that a finger of the rack interferes with the pin, engagement will not be possible until the occupant of the chair slightly shifts the position of the body-supporting portion of the chair such that the pin enters between two fingers of the rack. 
     Another drawback is the requirement of providing a long rack when a wide range of locking positions on the chair are desirable, which may not be aesthetically advantageous. 
     Against this background, it clearly appears that there is a need in the industry to provide a locking assembly for rocking chairs that avoids or at least alleviates drawbacks associated with prior art locking assemblies. 
     SUMMARY OF THE INVENTION 
     In one aspect the present invention provides a locking assembly for a rocking chair, the rocking chair having a body-supporting portion mounted for rocking movement on a chair base portion. The locking assembly comprises a first locking assembly component for mounting to the body-supporting portion and a second locking assembly component for mounting to the chair base portion. The first and the second locking assembly components can be interlocked to retain the body-supporting portion at a selected position relative to the chair base portion. 
     The first locking assembly component includes a pair of jaws capable to acquire two operative conditions. The second locking assembly component includes at least one pin. In the first operative condition, the jaws wedge the pin between them and thus retain the body-supporting portion of the chair relative to the base portion of the chair in a certain position, preventing the body-supporting portion of the chair from rocking. In the second operative position, the jaws release the pin, allowing the pin to move relative to the jaws such as to allow the chair to rock. 
     An advantage of the locking mechanism over prior art designs is its smoothness of operation. As the first locking assembly component is operated to cause the pin to become wedged between the jaws, the jaws and consequently the body-supporting portion of the chair, are guided toward the locking position when the jaws engage the pin. There is no necessity for the occupant of the chair to gage and adjust the position of the body-supporting portion of the chair relative to the chair base portion such as to allow the two components of the locking assembly to interengage. Another advantage of this locking assembly is its low profile. To extend the range of locking positions, it suffices to add more pins to the chair base, where each pin corresponds to a different locking position. Since the pins are relatively small, the locking mechanism remains discreet. 
     One possible variant of the structure described above is to reverse the position of the locking assembly components, and mount the first locking assembly component to the chair base portion while mounting the second locking assembly component to the body-supporting portion of the chair. 
     In a specific non-limiting example of implementation, the first locking assembly component includes a pair of jaws that move with relation to one another when a linkage is operated. Typically, the linkage includes a handle that extends on the side of the chair and that can be operated by the user to open or to close the jaws. The relationship between the jaws is such that when a movement is imparted to one jaw by the linkage, the other jaw is also caused to move. When the linkage is operated to engage the locking assembly, the jaws move with relation to one another such as to grip the pin. In particular, the gripping faces of the jaws undergo motions in two directions. First, the gripping faces move away from one another such as to define a receptacle for receiving the pin. Second, the gripping faces move down to come and bear on the pin, thus immobilizing it. The arrangement between the various parts forming the gripping assembly is such that during the initial phase of the locking assembly engagement, the gripping faces of the jaws move faster away from one another than toward the pin. This arrangements allows to first form the pin catching receptacle and then to cause the receptacle to fit on the pin such as to wedge the pin. When the locking assembly is released, the opposite sequence of motions occurs. 
     The present invention also extends to a rocking chair including the locking assembly described above. 
     In another broad aspect, the invention provides a chair with a body-supporting portion that moves relative to a chair base portion. The body-supporting portion has a backrest and a seat. A locking assembly is provided to prevent the movement of the body-supporting portion relative to the chair base portion. The chair has a linkage to operate the locking assembly. The linkage includes a resilient strip mounted on the backrest. When an occupant applies pressure on the backrest the strip is deformed rearwardly. When the pressure ceases, the strip returns to its original position. The linkage is coupled to the locking assembly to cause the locking assembly to operate and prevent the movement of the body-supporting portion when the strip is in its original position. Conversely, when the strip is deformed rearwardly, the locking assembly is disengaged. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a rocking chair incorporating the locking assembly constructed according to the principles of the present invention. In FIG. 1, only the structure of the chair is shown, the upholstery being removed for purposes of clarity; 
     FIG. 2 is an enlarged perspective view of the locking assembly shown in FIG. 1; 
     FIG. 3 is a further enlarged perspective view of the locking assembly depicted in FIG. 1, the locking assembly being engaged to prevent the chair from rocking; 
     FIG. 4 is a top plan view of the chair depicted in FIG. 1; 
     FIG. 5 is a schematical view of the locking assembly, depicting the relative position of the jaws of the first assembly component, showing the jaws in a position to grip a pin of the second locking assembly component; 
     FIG. 6 is a view similar to FIG. 5, showing the jaws in a position to allow the chair to rock; 
     FIG. 7 is a perspective view from the top of the locking assembly in accordance with the invention, some components of the chair being also illustrated to provide a frame of reference; 
     FIG. 8 is yet another perspective view from the top of the locking assembly in accordance with the invention, some components of the chair being also illustrated to provide a frame of reference; 
     FIG. 9 is yet another perspective view from a different angle of the locking assembly in accordance with the invention, some components of the chair being also illustrated to provide a frame of reference; 
     FIG. 10 is yet another different perspective view from the locking assembly in accordance with the invention, some components of the chair being also illustrated to provide a frame of reference; 
     FIG. 11 is a perspective view of the backrest of a rocking chair, illustrating a linkage responsive to pressure applied by the occupant of the chair to operate the locking assembly; 
     FIG. 12 is an enlarged front perspective view of the linkage shown in FIG. 11, illustrating details of the mechanism; 
     FIG. 13 is an enlarged rear perspective view of the linkage shown at FIG. 11; and 
     FIG. 14 is a perspective view of the first locking assembly component of the locking assembly, according to a variant, well suited for use with the linkage illustrated in FIGS. 11 to  14 . 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 of the drawings illustrates a chair designated by the reference numeral  20  that embodies the principles of the present invention. The chair  20  can be broken down into three main components namely a body-supporting portion  22 , a chair base portion  24  and a locking assembly  26  that allows the body supporting portion  22  to be interlocked with the chair base  24  at a selected position. 
     The body-supporting portion  22  comprises two main components namely a seat portion  28  and a backrest  30 . The chair base portion  24  comprises a circular member of sufficient size to adequately support the chair  20  on the floor, although this is only a question of design since a wide variety of chair base portions can be used here without departing from the spirit of the invention. 
     The body-supporting portion  22  is connected with the chair base portion  24  through the intermediary of a rocking mechanism  32  that allows the chair  20  to rock back and forth. The specific type of rocking mechanism is not critical for the success of this. As an example a rocking mechanism can be used that includes a horizontal bar  34  carrying at each end two hinges  36  and  38  that pivot about horizontal and parallel axes. A sub-frame  40 , mounted below the seat portion  28  is connected to the hinges  36 ,  38 , through links  42 , themselves pivotally mounted to the sub-frame  40  at  44 ,  46 , about horizontal axes that are parallel to the horizontal axes of the hinges  36 ,  38 . 
     The body-supporting portion  22  is mounted to the rocking mechanism  32  by generally vertical bars  48  extending between the seat portion  28  and the sub-frame  40 . This arrangement allows the body-supporting portion  22  to rock back and forth relative to the chair base portion  24 . 
     The locking assembly  26  is provided to lock the body-supporting portion  22  at a selected position with respect to the chair base  24 . In a specific example of implementation, the locking assembly  26  provides a plurality of positions in which the body-supporting portion  22  can be locked relative to the chair base portion  24 . 
     The structure of the locking assembly  26  is illustrated in greater detail in FIGS. 3 to  10 . The locking assembly  26  includes two components, namely a first locking assembly component  50  mounted to the body-supporting portion  22  and a second locking assembly component  52  mounted to the chair base portion  24 . The first locking assembly component  50  comprises a pair of jaws that are operated by a linkage. The second locking assembly component  52  includes a plurality of pins, each pin corresponding to a different locking position of the body-supporting portion  22  with relation to the chair base portion  24 . The locking assembly is in a locked condition when the jaws of the first locking assembly component  50  grip a pin of the second locking assembly component  52 . 
     With reference to FIG. 3, the first locking assembly component  50  comprises three generally parallel flat plates  54 ,  56  and  58  that are welded to a horizontal bar  60  forming part of the seat  28 . The purpose of the three plates  54 ,  56  and  58  is to provide a structure allowing to pivotally support the various elements of the first locking assembly component  50 . A pair of jaws  62  and  64  are mounted to the plates  54 ,  56 . 
     Referring now to FIG. 9, the linkage  66  includes a horizontal bar  68  of generally square cross-sectional shape bent to form an upwardly projecting portion  70  to which is mounted a handle  72 . The handle  72  extends at the side of the body-supporting portion  22  such as to be accessible to the occupant of the chair  20 . Note that the handle  72  may extend at either one of the two sides of the body-supporting portion  22 . The horizontal bar  68  is pivotally mounted in the plates  58 ,  56  and  54  in bushings  74 ,  76  (shown in FIG. 10) and  78 . In particular, the horizontal bar  68  is received in the central aperture of each bushing  74 ,  76  and  78  whose internal diameter is about the same as the diagonal length of the square cross-section of the horizontal bar  68 . Each bushing  74 ,  76  and  78  has a generally circular outer shape received in a mating aperture in the respective plate  54 ,  56  and  58 . To prevent the bushing  74 ,  76  and  78  from turning in the respective plate  54 ,  56  and  58 , each bushing  74 ,  76  and  78  is provided with a projection  80  received in a corresponding recess of the respective plate  54 ,  56  and  58 . 
     The jaw  62 , that is in the form of a plate including a curved gripping face  82  is mounted to the horizontal bar  68  such as to pivot with it when the handle  72  is moved by the occupant of the chair  20 . To accomplish this result, the jaw  62  is provided with a square aperture matching in size the cross-sectional shape of the horizontal bar  68 . The square aperture locks the jaw  62  on the horizontal bar  68  and prevents any relative angular movement of the jaw  62  with relation to the horizontal bar  68 . 
     The jaw  64  is also in the form of a flat plate with a gripping face  84  having about the same curvature as the curvature of the gripping face  82 . The jaw  64  is pivotally mounted to the plate  56  at the pivot point  86 . Motion is communicated from the jaw  62  to the jaw  64  by a short link  88  pivoted at  90  at the jaw  62  and at  92  at the jaw  64 . 
     Referring to FIG. 2, the second locking assembly component  52  includes a plurality of pins  94 ,  96  and  98  that are disposed along an arc of circle that follows the path of travel of the first locking assembly component  50  when the chair  20  is rocking. Each pin  94 ,  96  and  98  corresponds to a different locking position of the locking assembly  26 . 
     The operation of the locking assembly  26  is shown in greater detail in FIGS. 5 and 6. In FIG. 6, the locking mechanism  26  is in the un-locked position. In this position, the jaws  64  and  62  are retracted upwardly such as to clear the pins  94 ,  96  and  98 . This allows the chair  20  to rock since there is no interference between the first locking assembly component  50  and the second locking assembly component  52 . 
     FIG. 5 illustrates the position of the jaws  64  and  62  when the locking assembly is locked. The locking position is accomplished by causing the horizontal bar  68  to pivot by operating the handle  72 . The pivotal movement of the horizontal bar  68  causes a turning motion of the jaw  62  in one direction. A similar motion but in the opposite direction is also imparted to the jaw  64  by the intermediary of the link  88 . The geometrical shape of the jaws  62  and  64 , in particular the shape of the curved gripping faces  82  and  84  are selected such as when the handle  72  is operated to lock the chair  20 , the gripping faces  82 ,  84  move down and at the same time open sideways to wedge between them a pin (pin  94  shown in this example). It will be noted from FIG. 5, that the gripping face  82  has a lower portion  100  that is at a shorter distance from the pivot point  102  of the plate  54  (the point at which the plate  54  is mounted to the horizontal bar  68 ) than the distance between the pivot point  102  and the upper portion  104  of the gripping face  82 . When each portion  100 ,  104  is shaped as an arc of circle it means that the radius of the arc of the portion  100  is less than the radius of the arc of the portion  104 . 
     This configuration allows the gripping faces  82 ,  84  during the initial phase of the locking movement to move faster laterally (open-up) than downwards. Accordingly, the jaws  64 ,  62  during the initial phase of the locking movement spread laterally rapidly such as to form a receptacle  106  between their gripping faces  82 ,  84  and &lt;&lt;catch&gt;&gt; a pin  94 ,  96  or  98 . Note that the lateral movement is effected with respect to a plane of reference that is normal to the axis of the pin  94  and also parallel to the jaws  62 ,  64 . Subsequently, the jaws  64 ,  62  move down more rapidly such as to cause the pin to enter the receptacle  106  and become wedged in a pin-retention area  108  of the receptacle where the pin is engaged by both gripping faces  82 ,  84 . If during the downward movement of the jaws  62 ,  64  the pin  94  is not exactly centered between the two gripping faces  82 ,  84 , the pin  94  will initially bear on one of the gripping faces  82 ,  84 . The tapering gripping faces  82 ,  84  will guide the pin toward the pin-retention area  108 . 
     The locking assembly  26  is disengaged by rotating the horizontal bar  68  in the other direction. This causes the jaws  62 ,  64  to pivot in the opposite directions such as to displace the gripping faces  82 ,  84  first up and then laterally toward one another until the position in FIG. 6 has been reached. In this position, the pin is released from the jaws  62 ,  64  and the body-supporting portion  22  of the chair  20  is free to rock with respect to the chair base portion  24 . To prevent the locking assembly  26  from moving beyond the position shown at FIG. 6, a stop is provided. The stop includes a pin  110  that projects from the jaw  64  and that engages a tooth  112  extending from the plate  54 . 
     FIGS. 11 to  14  illustrate a variant. FIG. 14 is a perspective view of the first locking assembly component  200  that is suitable for use with a cable-operated linkage that will be described later. The first locking assembly component  200  works in conjunction with a second locking assembly component, not shown in FIG. 14, that is identical to the second locking assembly component  52  described earlier, including a plurality of pins defining different locking positions. As mentioned earlier, the first and second locking assembly components can be mounted to the body-supporting portion of the chair and to the chair base, respectively. The reversal is also possible, where the first locking assembly component is mounted to the chair base while the second locking assembly component is mounted to the body-supporting portion of the chair. 
     The first locking assembly component  200  includes a support member  202  in the form of a metallic plate that has a vertical part  204  and a horizontal part  206 . The horizontal part  206  includes downwardly bent lip  208  with a slot  210  therein for receiving a cable  212  that operates the locking assembly, the cable  212  thus forming part of the linkage in this variant example of implementation. The cable  212  has a core member  214  that moves in a sheath  216 . The size of the slot  210  is sufficient to accommodate the core  214  such that it can move therein, while blocking the sheath  216 . 
     The first locking assembly component  200  further includes a pair of jaws  218  and  220  pivotally mounted at pivot points  222  and  224 , respectively, on the vertical part  204 . The jaws  218  and  220  have respective gripping faces  226 ,  228 , generally opposite to one another. In addition, the jaws have camming faces  229 ,  231 . 
     The jaws  218  and  220  have arcuate slots  230  and  232 . The slots  230  and  232  are formed in such a way that they overlap one another, at least partially. Under this variant, another component of the linkage is an actuator bar  234  having a pin  236  received in the slots  230  and  232 . The actuator bar  234  is pivoted at  238 . The pivot point  238  defines a pivot axis that is generally parallel to the pivot axis of pivot points  222  and  224 . The core  214  of the cable  212  is fastened to the actuator bar  234  at a point intermediate the pin  236  and the pivot point  238 . Thus, by pulling the cable core  214 , the actuator bar is caused to turn clockwise imparting, in turn, a pivotal movement to both jaws  218 ,  220  through the interaction between the pin  236  and the slots  230 ,  232 . 
     The actuator bar  234  is urged to pivot counterclockwise to a lower limit position, by a coil spring  240 . The lower limit position is a position where the arcuate slots  230 ,  232  will no longer allow the pin  236  to move. More specifically, as the actuator bar  234  pivots in a counterclockwise direction, the pin  236  travels downwardly. The pin  236  rides in the arcuate slots  230  and  232  which also move since the jaws  218 ,  220  travel downwardly under the effect of gravity. During this downward travel the jaws  218 ,  220  part their gripping faces  226 ,  228 . The geometry of the slots  230 ,  232  and of the actuator bar  234  is such that as the jaws  218 ,  220  move downwardly, the pin  236  becomes wedged in the slots  230 ,  232 . The pin  236  can no longer move down anymore and this constitutes the lower limit position. 
     In order to ensure that both jaws  218 ,  220  will move downwardly when the actuator bar  234  pivots counterclockwise, coil springs  242 ,  244  are provided on the pivot points  222 ,  224 , respectively to urge the jaws  218 ,  220  downwardly. 
     The linkage that operates the first locking assembly component  200  will now be described in connection with FIGS. 11,  12  and  13 . The linkage component  300  is mounted on the backrest  30  of the chair and is responsive to pressure applied by an occupant seated in the chair. More specifically, the linkage component  300  is designed to actuate the locking assembly such as to prevent the chair from rocking when no pressure is applied to the linkage component  300 . Thus, when no one is sitting in the chair, the locking assembly precludes any rocking movement. 
     The linkage component  300  includes a forwardly bowed strip  302  that extends across the two vertical posts  304 ,  306  of the backrest  30 . The bowed strip  302  is permanently attached to the post  306 . In contrast, the bowed strip  302  is mounted at the other end to a plate  308 , which can slidingly move on a bed  310 , attached to the post  304 . The bowed strip  302  is normally under the upholstery of the chair. The bowed strip  302  is made of material that is sufficiently resilient such that when no pressure is exerted on the backrest  30  of the chair, the strip  302  is in the bowed configuration, as shown at FIG.  11 . On the other hand, when an occupant sits in the chair and applies pressure on the backrest  30 , the strip  302  will distort to the rear, causing the plate  308  to slide relative to the bed  310 . 
     The bowed strip  302  can be made of plastic material having the necessary resiliency characteristics. 
     As shown in FIG. 12, the plate  308  is mounted at one end to the bowed strip  302 . At the other end, the plate  308  has a lip  312  to which is mounted the cable  212 . The cable section between the linkage component  300  and the locking assembly is not shown in the drawings for simplicity. The cable  212  can be routed as required between the two components. The lip  312  is provided with a slot  314  to slidingly receive the cable core  214  while blocking the cable sheath  216 . The cable core  214  is mounted to the end of an arm  316  keyed to a pin  318 . The pin  318  is received in a slot  320  whose length defines the range of movement of the plate  308  with relation to the bed  310 . 
     With reference to FIG. 13, the pin  318  projects from the back of the bed  310  and supports a lever  322 . Turning the lever  322  between abutments  324  and  326  causes the pin  318  and the arm  316  to undergo the same amount of angular displacement. 
     To summarize, when an occupant is sitting in the chair and leaning back against the backrest  30 , the bowed strip  302  is distorted backwardly which has the effect of straightening the strip  302 . Since the end of the strip  302  is fixed at the post  306 , the other end of the strip  302 , which carries the plate  308 , will move laterally outwardly with relation to the bed  310 . Since the core  214  of the cable  212  is fixed, this sliding movement will cause the sheath  216  to move over the core  214 , thus unlocking the locking assembly. More specifically, the movement of the cable sheath  216  causes the cable core  214 , at the level of the first locking assembly component  200  to be pulled, thus raising the actuator bar  234  and the jaws  218  and  220 , against the resiliency of the springs  240 ,  242  and  244 . 
     When the pressure acting on the bowed strip  302  ceases, the reverse happens. The cable sheath  216  retracts on the core  214 , thus the pulling force applied on the actuator bar  234  by the cable core  214  stops. As a result, the actuator bar  234  and the jaws  218  and  220  descend to engage the second locking assembly component. 
     The role of the lever  322  is to disable the operation of the locking assembly. When the lever  322  is turned counterclockwise (as viewed in FIG. 13) up to the abutment  326 , it causes the pin  318  to pivot about a quarter of a turn, which brings the arm  316  generally horizontal. This pulls the cable core  214  and has the same general effect on the system as when a person sits on the chair and applies pressure on the backrest  30 . The locking assembly is deactivated and the chair can rock irrespective of whether pressure is applied on the backrest or not. To restore the functionality of the locking assembly  200 , the lever is turned back to a position where it engages the abutment  324 . 
     Referring back to FIG. 14, the operation of the first locking assembly component will be discussed in greater detail. As with the previous embodiment, the jaws  218  and  220  form between them a receptacle  400  to catch any one of the pins of the second locking assembly component. For clarity, the second locking assembly component is not shown in FIG. 14, its structure and operation being identical to the second locking assembly component  52 . 
     In the event that the first locking assembly component  200  operates but not one of the pins of the second locking assembly component precisely registers with the receptacle  400 , the camming faces  229  and  231  will cause the jaws  218 ,  220  to yield upwardly when engaging any one of the pins. Assume for the purpose of the present discussion that the jaws  218  and  220  are located precisely between two pins of the second locking assembly component. The pins shown in dotted lines are identified by the references  402  and  404 . In this position, it will be evident that the jaws  218 ,  220  cannot engage any one of the pins  402 ,  404  since the camming surfaces  229  and  231  rest on the pins  402  and  404 . However, the ramps of the respective camming surfaces  229  and  231  are such that when the body-supporting portion  22  moves, the jaws  218 ,  220  will be raised upwardly, against the resiliency of the coil springs  242 ,  244 . This movement is also allowed by virtue of the arcuate slots  230 ,  232  in which the pin  236  can move. Say that the movement of the body-supporting portion  22  occurs in the direction of the arrow  406 . The jaw  220  will be raised until the jaw  220  has cleared the pin  402 , at which point the jaw  220  will descend and the pin  402  will be captured in the receptacle  400 . The same sequence of events will happen with the jaw  218  if the body-supporting portion  22  moves in the opposite direction. 
     The above described feature operates as a ratchet, allowing the body-supporting portion  22  to move until any one of the pins of the second locking assembly component is firmly engaged in the receptacle  400 . 
     It is intended that the present application covers the modifications and variations of this invention provided that they come within the scope of the appended claims and their equivalents.