Abstract:
A rocking chair comprising a base, a seat assembly including a seat rockably mounted to the base and a backrest mounted to the seat so as to be movable between first and second positions includes a couple of biasing members mounted to the backrest for biasing the backrest towards the first position, and a locking mechanism mounted to both the base and the seat assembly for locking the seat relatively to the base when the backrest is in the first position. The locking mechanism is operated by applying at least a threshold force onto the backrest, which causes the backrest to move between the first and second positions relatively to the seat, unlocking the backrest relatively to the base, and allowing the seat to move relatively to the base. The locking mechanism includes a toothed rack and an arm lever that operatively cooperate in response to a small force exerted on the backrest. The rocking chair is safe for people having hand or forearm disability problem and for people with reduced mobility.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to rocking chairs. More specifically, the present invention is concerned with a locking chair provided with an automatic locking mechanism.  
       BACKGROUND OF THE INVENTION  
       [0002]     Rocking chairs provided with a locking mechanism for preventing rocking movements while a person attempts to rise from the chair or to sit thereon have been known since many years. Generally, the chair comprises a fixed base, a seat rockably mounted to the base, and a locking mechanism mounting to the chair for selectively immobilizing the seat relatively to the base.  
         [0003]     Locking mechanism comes in two flavours: manually operated and automatic. Examples of rocking chairs equipped with a manually operated locking mechanism are described in the U.S. Pat. No. 6,120,094, issued to Parent on Sep. 19, 2000 and entitled “Rocking Chair with Automatic Locking Device”, and in the U.S. Pat. No. 6,213,551, entitled “Chair Locking Mechanism”, issued to Desnoyers et al. on Apr. 10, 2001.  
         [0004]     A drawback of such rocking chairs is that the lever of the locking mechanism may be difficult to operate for people having hand or forearm disability problems and for people with reduced mobility.  
         [0005]     Bouchard et al., in the U.S. Pat. No. 6,406,095, issued on Jun. 18, 2002 and entitled “Self-Locking Mechanism” propose a solution to the above-mentioned drawback in the form of a locking mechanism intended to be automatically actuated while the occupant is still assuming a normal sitting position. The proposed locking mechanism comprises a detector for establishing whether a person is sitting on the chair, a lock, and an actuator for unlocking the lock when the presence of the person on the chair has been detected. The detector is responsive to pressure onto the backrest of the chair.  
         [0006]     A first drawback of Bouchard&#39;s self-locking mechanism is the important number of its components and its complexity, yielding a mechanism bound to malfunction and an overall chair expensive to manufacture. A second drawback is that Bouchard&#39;s self-locking mechanism is uncomfortable and difficult to operate.  
       OBJECTS OF THE INVENTION  
       [0007]     An object of the present invention is therefore to provide an improved locking mechanism for a rocking chair.  
       SUMMARY OF THE INVENTION  
       [0008]     More specifically, in accordance with the present invention, there is provided a rocking chair comprising: 
        a base;     a seat assembly movably mounted to the base; the seat assembly including a seat and a backrest; the backrest being movable between first and second backrest position&#39;s relatively to the seat;     at least one biasing member mounted to the backrest for biasing the backrest towards the first backrest position; and     an automatic locking mechanism mounted to both the base and the seat assembly for locking the seat relatively to the base when the backrest is in the first backrest position; 
 
 whereby, in operation, applying at least a threshold force onto the backrest causes the backrest to move between the first and second backrest positions relatively to the seat, unlocking the backrest relatively to the base, and allowing the seat to move relatively to the base. 
       
 
         [0014]     Other objects, advantages and features of the present invention will become more apparent upon reading the following non restrictive description of preferred embodiments thereof, given by way of example only with reference to the accompanying drawings.  
         [0015]     It is to be noted that the expression “rockably” used herein in reference to the movement of the seat relatively to the base is to be construed so as to encompass any movable relationship between the seat or the seat assembly and the base, including but not limited to rocking, swinging, rotating, and any other more complex movement.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]     In the appended drawings:  
         [0017]      FIG. 1  is a side elevation view of a rocking chair according to an illustrative embodiment of the present invention;  
         [0018]      FIG. 2  is a partial cross section of the rocking chair from  FIG. 1 , illustrating the rocking chair in a locked configuration;  
         [0019]      FIG. 3  is a cross section taken along line  3 - 3  on  FIG. 1 , illustrating a biasing member according to an illustrative embodiment of a secondary aspect of the present invention, the biasing member being illustrated in a passive configuration;  
         [0020]      FIG. 4  is a cross section similar to  FIG. 3  illustrating the biasing member in a working configuration; and  
         [0021]      FIG. 5  is a cross section similar to  FIG. 2 , illustrating the rocking chair in an operating configuration. 
     
    
     DETAILED DESCRIPTION  
       [0022]     Turning now to  FIGS. 1 and 2  of the appended drawings, a rocking chair  10  provided with an automatic locking mechanism  12  according to an illustrative embodiment of the present invention is illustrated.  
         [0023]     The rocking chair  10  comprises a base  14 , a seat assembly  16  including a seat  36  rockably mounted to the base  14  via a frame assembly  18  and a backrest  34  mounted to the seat  36  so as to be movable between first and second positions, a pair of biasing members  20  (only one shown), each mounted to both the backrest  34  and to the seat  36  via the frame assembly  18 , for biasing the backrest  34  towards the first position, an automatic locking mechanism  12 , and a safety locking mechanism  21 . Each of these components of the rocking chair  10  and their relationships will now be described in more detail.  
         [0024]     The base  14  includes bottom and top rectangular frames  22 - 24 , the top frame  22  being biased from the bottom frame  24  and supported by the rods  26 . The base  14  and more specifically the bottom rectangular frames  22  are configured and sized so as to provide stability to the chair  10 . Of course, the base  14  may have other configuration allowing supporting and rockably mounting the seat assembly  16  via the frame assembly  18 .  
         [0025]     The frame assembly  18  includes two tubular generally S-shape frame members  28  (only one shown), each rockably mounted to a side of the rectangular base  14  via two elongated mounting members  30 . The S-shape members  28  are in the form of bended hollow tubing. The upper portion of each S-shape member  28  defines an armrest.  
         [0026]     More specifically, a first longitudinal end of each mounting member  30  is pivotally mounted to the bottom leg of a respective S-shape member  28  near a longitudinal end thereof, while the other longitudinal end of the mounting member  30  is pivotally mounted to a beam of the top rectangular frame  22  near a longitudinal end thereof so as to allow a rocking movement between the S-shape member  28  and the frame assembly  14 .  
         [0027]     The S-shape members  28  are mounted to opposite sides of the base  14 . Each mounting member  30  is secured near the respective corners of the rectangular frames  22 - 24  so as to improve stability. For that same purpose, the bottom frame  24  is oversized with respect to the top frame  22 .  
         [0028]     Each S-shape member  28  includes reinforced rods  32  and  34  between respectively the top and bottom leg portions and the center portion of the S-shape member  28 .  
         [0029]     Of course, the frame assembly  18  may have other configurations allowing to rockably mounting the seat assembly  16  to the base  14 .  
         [0030]     The backrest  34  of the seat assembly  16  is pivotally secured to both S-shape members  28  of the frame assembly  16  therebetween via the biasing members  20  (only one shown) near its top longitudinal end and via the automatic locking mechanism  12  near its bottom longitudinal end. The operational relationship between the backrest  34  and the S-shape members  28  via the automatic locking mechanism  12  will be described hereinbelow in more detail.  
         [0031]     The seat  36  is mounted to the S-shape member  28  and to the automatic locking mechanism  12  via mounting elements such as the mounting brackets  72  and  98  respectively.  
         [0032]     Turning now to  FIG. 3 , one of the two identical biasing members  20  and its operating relationship with a corresponding S-shape member  28  will be described in more detail.  
         [0033]     The biasing member  20  is in the form of an elongated hollow body  38  including first and second longitudinal end openings  40 - 42  and a spring  44  extending therein from the first to the second longitudinal opening  40 - 42 . The two end rings  46 ′- 46  of the spring  44 , located respectively at the proximate and distal ends thereof, are bent so as to be oriented perpendicularly from the other rings of the spring and perpendicularly from one another. The spring  44  is configured and sized so that the two end rings  46 - 46 ′ extend partially from their respective opening when the spring  44  is in a passive or non-working configuration. The end ring  46 ′ is secured to the hollow body  38  near the second longitudinal end  42  via a spring pin  48 . The end ring  46  is secured to the hollow tubing of the S-shape member  28  therein via a bolt  50  mounted to the hollow tubing through a transversal opening  51 . The hollow body  38  is tapered near its distal end  40  so as to ease its longitudinal forward movement in the upper leg section of the S-shape member  28  when it is mounted therein during assembly.  
         [0034]     A first transversal opening  52  in the hollow body  38  allows receiving a bolt  54  that is secured to the hollow body  38  via a complementary nut  56 . The bolt  54  is fixedly mounted to a mounting plate  58  that is part of a mounting assembly  60  allowing to fixedly securing the hollow body  38  to the backrest  34 . Of course, the S-shape member  28  includes an opening  61  configured and sized to allow passage for the bolt  54  and to allow a transversal course therein.  
         [0035]     The mounting assembly  60  further includes a bolt  62  or any other fastening means for securing the mounting plate  58  to the tubular member of the backrest  34 .  
         [0036]     Of course, other fastening means can be used to secure the backrest  34  to the hollow body  38  and therefore to the S-shape member  28  since the hollow body  38  is mounted in the S-shape member  28 .  
         [0037]     In operation, the biasing member  20  is in its passive configuration illustrated in  FIG. 3  when no force is exerted on the backrest  34  (see  FIG. 1 ). The backrest  34  is then in its first position defining a first angle with the upper portion of the S-shape member  28 . However, when a force is exerted on the backrest  34 , the backward translation of the backrest  34  is transferred to the biasing member  20  via the mounting assembly  60  until the bolt  54  reach the end of its course as allowed by the dimension of the opening  61  (see  FIG. 4 ). Also, at the end of its course, the biasing member  20  is stopped by the friction member  64 . The biasing member  20  is then in a working configuration since it is tensioned. The biasing member  20  and more specifically the spring  44  is so configured that only a minimal pressure is required to move the backrest  34 .  
         [0038]     The backrest  34  is in its second position when the biasing member  20  is at the end of its course, abutting the friction member  64 . In its second position, the backrest defines a second angle with the upper portion of the S-shape member  28 , the second angle being greater than the first angle. It is reminded that the first angle is defined with the upper portion of the S-shaped member  28  when the backrest is in its first position.  
         [0039]     The spring  44  may be replaced by other biasing means such as a stretchable band, for example made in rubber.  
         [0040]     The biasing member  20  may take other forms allowing to force the backrest  34  in a first position until a sufficient force is exerted to move the backrest  34  in a second position. For example, the biasing member  20  may have other configurations allowing its cooperation with the backrest  34  when the backrest  34  is configured to perform other movements than tilting between the first and second position.  
         [0041]     Also the biasing member  20  may be differently positioned. For example, a biasing member  20  may alternatively or additionally be directly mounted to both the backrest  34  and the seat  32  therebetween. The biasing member  20  may alternatively be positioned at a different location than illustrated in  FIG. 1  between the frame assembly  18  and the backrest  34 .  
         [0042]     Returning to  FIG. 1 , the safety locking mechanism  21  is in the form of two friction members  64  (only one shown) pivotally mounted to the upper end portion  66  of the S-shaped member  28  via a rod  68 . The two friction members  64  are positioned along the rod  68  so as to engage lateral frame portions  70  of the backrest  34  while pivoting. A handle  72 , fixedly mounted to both friction members  64 , allows pivoting the friction members  64  between a first position where they contact the backrest  34  and a second position (as illustrated in  FIGS. 1, 3  and  4 ), where it is sufficiently biased from the backrest to allow the hollow body  38  of the biasing member  20  to move its full course. In their first contacting position, the friction members  64  prevent any backward movement of the backrest  34 . Moreover, as will become more apparent hereinbelow, the safety locking mechanism  21 , while in its first position, prevents the rocking chair  10  from rocking.  
         [0043]     Even though the safety locking mechanism  21  has been described has having two friction members  64 , only one friction member may be used in preventing movements of the backrest  34  and therefore movements of the seat assembly  16  relative to the base  14 .  
         [0044]     The safety locking mechanism  21  may alternatively have another configuration allowing preventing movement of the backrest  34 . For example, the safety locking mechanism  21  may be mounted to both the backrest  34  and base  14  or seat  36  and configured to selectively engage the two components  34  and  14  or  36  so as to prevent any relative movement therebetween.  
         [0045]     The automatic locking mechanism  12  will now be described in more detail with reference to  FIGS. 1, 2  and  5 .  
         [0046]     The automatic locking mechanism  12  includes a pair of toothed racks  74  and a pair of lever arms  76  operatively interconnected.  
         [0047]     Each lever arm  76  includes an elongated portion  78  and an integral shorter portion  80  extending from the elongated portion  78  at an obtuse angle so as to generally define an open L-shape body having an elbow portion  81 . Each arm  76  is pivotally mounted through its elbow portion  81  to a respective lateral side of the seat  36  via a pivot pin  82 . The free end  84  of the shorter portion of each arm  36  is provided with a groove  85  to receive a first transversal rod  86  extending laterally side to side of the chair  10  in the backrest  34 . The free end  88  of the elongated portion  78  includes an aperture  89  to pivotally mount the arm  76  to a second transversal rod  90  that is secured to both S-Shape members  28  therebetween. Therefore, the lever arm  76  interconnects the backrest  34  and the frame assembly  18 .  
         [0048]     The toothed racks  74  are mounted to each other via third and fourth transversal rods  92 - 93  that are positioned near each of their respective first and second longitudinal ends  94 - 96 . A mounting bracket  98  allows to additionally pivotally mounting the fourth transversal rod  93  to the bottom of the seat  36 . The arm  74  further includes a finger  100  extending from the rack  74  so as to define a groove  102  for receiving the second transversal rod  90  that acts as a second pivot axis for the arm  76 . The finger  100  extends from the arm  76  at a position about one third of a distance&#39;between the third and fourth transversal rod  92 - 93 . Of course, the position of the finger may vary.  
         [0049]     Each rack  74  also includes a toothed portion  104  defined by a plurality of grooves  106  each defining an arc. The grooves  106  are configured to selectively engage a small rod  108  protruding from the top rectangular frame  22  of the base  14  towards the interior of the base  14 .  
         [0050]     Then toothed rack  74  allows selectively interconnecting both the seat  36  and backrest  34  to the base so as to selectively prevent any rocking movement of the seat assembly  16  relatively to the base  14 .  
         [0051]     The plurality of grooves  106  allows to selectively locking the seat assembly  16  while the seat assembly  12  is in one of a plurality of position relatively to the base  16 .  
         [0052]     In operation, a person (not shown) unlocks the safety locking mechanism  21  by upwardly pivoting the handle  72  so as to disengage the resilient bodies  64  from the back of the lateral frame members  70  of the backrest  34 , as illustrated in  FIG. 1 . Of course, the safety locking mechanism  21  is not required to be engaged between uses of the chair  10 .  
         [0053]     Without any force or pressure exerted on the backrest  34 , the biasing member  20  (see  FIG. 3 ) forces the backrest  34  in the locked position illustrated in  FIGS. 1 and 2 . In this locked position, the toothed rack  74  and lever arm  76  are so positioned that one of the grooves  106  engages the rod  108 , which prevent any relative movements between the base  14  and the seat assembly  16 . The longitudinal position of the toothed rack  74  relatively to the base  14  when a person wishes to get up from the chair  10  and therefore stops putting some pressure with its back on the backrest, determines which groove  106  engages the rod  108 . Of course the number, size and configuration of the grooves  106 , and the configuration and size of the rod  108  may vary. For example, the rod  108  may be replaced by a protrusion having another configuration.  
         [0054]     When the safety locking mechanism  21  is unlocked and a person sitting in the chair  10  exerts a minimal force onto the backrest  34 , the backrest  34  pivot backwardly as indicated by arrow  110  on  FIG. 5 .  
         [0055]     The pivoting of the backrest  34  caused by exerting a pressure thereon causes the pivoting of the lever arm  76  in a way that its elongated portion  78  raises. Consequently, this causes the raising of the toothed portion  104  of the toothed rack  74  (see arrow  112  on  FIG. 5 ), disengaging any engaged groove from the rod  108 . This allows the S-shaped members  28 , and therefore the seat assembly  18  mounted thereto, to freely swing in both longitudinal directions as indicated by arrows  114  in  FIG. 5 .  
         [0056]     It is to be noted that the automatic locking mechanism  12  according to the present invention makes use of the lever effect, allowing the mechanism  12  to be disengage by persons having a weight as low as 40 kilograms for example, depending on the configuration and size of the locking mechanism.  
         [0057]     Although the present invention has been described with reference to a rocking chair provided with a frame assembly including S-shape members, it is believed to be within the reach of a person having skills in the art to adapt the present invention to a rocking chair having other configuration and more specifically other frame assembly configuration.  
         [0058]     Moreover, the configuration of the lever arm  76  and toothed rack  74  may vary. Also other cooperating means than grooves with a rod can be foreseen between the rack  74  and the base  16 . The biasing member can also take other forms.  
         [0059]     Even though the present invention as been described with reference to an illustrative embodiment wherein the seat or seat assembly is rockable relatively to the base, it is believed to be within the reach of a person skilled in the art to use the present teaching to adapt the automatic locking mechanism to a chair where a seat assembly is movably mounted to a base so as to allow another movement than rocking, such as rotation, tilting, etc.  
         [0060]     Although the present invention has been described hereinabove by way of preferred embodiments thereof, it can be modified without departing from the spirit and nature of the subject invention, as defined in the appended claims.