Abstract:
A portable massage chair uses a multi-disk friction clamp to permit adjustment of a chest support member. The chair may be collapsed or set up for use by alternately connecting and disconnecting a rigid triangular support structure formed by a seat support frame portion, a chest support frame portion, and a knee support frame portion.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims priority under 35 U.S.C. § 120 of PCT Application No. PCT/US02/39967 filed Dec. 13, 2002 titled “Portable Massage Chair” and is hereby incorporated by reference in its entirety.  
         [0002]     This application incorporates by reference in its entirety for all purposes U.S. Provisional Patent Applications Ser. No. 60/340,463, filed Dec. 14, 2001 and Ser. No. 60/380,518, filed May 13, 2002. 
     
    
     FIELD OF THE INVENTION  
       [0003]     The invention relates to collapsible chairs, particularly chairs that are adjustable for supporting people of different sizes in position for massage.  
       BACKGROUND OF THE INVENTION  
       [0004]     Chairs are often used to support a person for massage. A typical massage chair supports a person&#39;s seat, chest, and head in a forward leaning orientation so that a person&#39;s back, shoulders and neck are readily accessible to the masseuse. It is desirable for massage chairs to be adjustable to accommodate people of different heights, and body configurations. Another objective is for massage chairs to be collapsible, portable and light weight. This allows a masseuse to use the same chair to conduct massage at different locations.  
         [0005]     Many portable massage chairs have been designed and used in the past. However, there is still a significant need for new chair designs that provide improved adjustment mechanisms, in a lightweight, sturdy, collapsible design that is relatively inexpensive and straight forward to manufacture.  
       SUMMARY OF THE INVENTION  
       [0006]     The invention provides a chair including a seat attached to a front leg structure. A chest support is attached to a rear leg structure and a knee support structure. The front leg structure and the rear leg structure cross at a pivotally connected juncture. The knee support structure is pivotally connected to a lower portion of one of the leg structures. The other end of the knee structure may be removably attached to the other leg structure to form a rigid triangulated support for the chair when it is in the open condition.  
         [0007]     The invention also provides a mechanism for permitting adjustability of a support member such as a chest support. The adjustment mechanism uses a clamp on plural frictional locking disks positioned along a common axis. The frictional force between the disks is relieved when the clamp is unlocked. When the clamp is locked, the frictional force between the disks prevents movement between the support member and a related frame structure. A handle is connected to the clamp. The handle is movable between first and second positions to lock and unlock the clamp by applying and relieving pressure. In a preferred embodiment of the invention, the disks include alternating round and square or rectangular disks in a housing that prevents the square or rectangular disks from rotating relative to the frame structure.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]      FIG. 1  is a perspective view of the massage chair of the present invention, shown in the unfolded position.  
         [0009]      FIG. 2  is a side view of the massage chair of the present invention, shown in the unfolded position.  
         [0010]      FIG. 3  is a side view of the massage chair of the present invention, shown in the folded position.  
         [0011]      FIG. 4  is a perspective view of the massage chair of the present invention, shown in the unfolded position without the face rest  11  or the arm rest  12  and with the chest support clamping mechanism exploded.  
         [0012]      FIG. 5  is a partial enlarged view of a portion of the chair shown in  FIG. 4 .  
         [0013]      FIG. 6  is cross-sectional view A-A of the chair shown in  FIG. 2 .  
         [0014]      FIG. 7  is a partial cross-sectional view of an alternate type of frictional clamp.  
         [0015]      FIG. 8  is a partial cross-sectional view of the clamp shown in  FIG. 7 .  
         [0016]      FIGS. 9-13  are schematic views of alternative chair designs. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0017]     Massage chair  10  accommodates a person (not shown) who would sit in the chair with their buttocks on seat  14 , their chest on chest support  13 , their face against face rest  11 , their forearms resting on arm support  12 , and their knees and lower legs on right and left knee rests  17   a  and  17   b.    
         [0018]     The chair can be described as being comprised of three subassemblies, a seat subassembly, an upper body support subassembly and a knee and leg support subassembly.  
         [0019]     The seat subassembly is comprised of two front leg rails  18   a  and  18   b,  which are rigidly attached to front leg cross member  35  and support seat  14  and knee pivot rod  20 .  
         [0020]     The upper body support subassembly is comprised of main rail  15 , which is rigidly attached to rear leg cross member  36  and arm support rail  37 . This frame assembly supports chest support  13 , face rest  11  and armrest  12 .  
         [0021]     The knee and leg support subassembly is comprised of knee support rails  16   a  and  16   b,  which are rigidly attached to knee support cross rail  38  and guide plated  19   a  and  19   b  and pivotally attached to main rail  15  at point  38 . This frame assembly supports knee rests  17   a  and  17   b.    
         [0022]     The seat subassembly is pivotally attached to the upper body subassembly by main pivot rod  37  allowing the two subassemblies to form an “X” shape. These first two subassemblies are held rigidly in one of three open positions by the knee rail subassembly when knee pivot rod  20  is engaged in one of three hook shaped slots in guide plates  19   a  and  19   b.  This causes the three subassemblies to form a rigid triangle connecting pivot points  20 ,  37  and  38 .  FIG. 2  shows the knee pivot rod engaged in the center hook shaped slot on guide plates  19   a  and  19   b.  When the knee pivot rod is engaged in the forward hook shaped slot the “X” formed by the seat and upper body subassemblies will broaden causing seat  14  to be supported in a lower position. When the knee pivot rod is engaged in the rear hook shaped slot the “X” formed by the seat and upper body subassemblies will narrow causing seat  14  to be supported in a higher position. This allows shorter and taller massage therapists to seat clients at a height that is comfortable for the therapist to work on them. The knee pivot rod  20  can be moved to either of the other two hook shaped slots in guide plates  19   a  and  19   b  by pivotally manipulating the knee and leg support subassembly and the seat subassembly about pivot points  38  and  37  respectively.  
         [0023]      FIG. 3  shows the chair in the folded closed position. The closed position is used to transport and store the chair more easily. The chair is folded by manipulating the seat and knee subassemblies to slide the knee pivot rod  20  to the forward end of the slots in guide plates  19   a  and  19   b.  This will bring front leg cross member  35  to contact armrest rail  37  with pawl  23  positioned just below it. Two armrest brackets  22  are pivotally attached to arm rest rail  37  at point  39 . Armrest  12  in attached to the top of the armrest brackets  22  and pawl  23  is attached between the lower portion of the brackets. The armrest is held in the open position as shown in  FIG. 2  by a spring-loaded button  21  attached to armrest rail  37  engaging in hole  40  in armrest bracket  22 . To lock the chair in the folded closed position button  21  is depressed and the armrest brackets and their attached parts are rotated about point  29  until the button  21  is engaged in hole  41 . This causes pawl  23  to capture front cross member  35  locking all three subassemblies in the closed position. The chest support and face rest may be further folded into compact closed positions as shown in  FIG. 3  by unlocking their respective locking levers  25  and  42 , moving them into position and locking the levers. Some compression of the foam of face rest  11  against armrest  12  will occur.  
         [0024]     As shown in  FIG. 5 , chest support  13  is attached to main rail  15  by a multi-disk friction clamp that allows the chest support to be raised and lowered as well as rotated relative to main rail  15 . Housing  31  is rigidly attached to main rail  15 . The square outer lock disks  29  are rotationally constrained by the square shape of housing  31  while allowing lock rod  27  to rotate freely inside the large center hole of outer lock disks  29 . Round inner lock disks  28  are rotationally keyed to lock rod  27  by their rectangular center hole and free to rotate within housing  31 . Inner and outer lock disks  28  and  29  may be alternately arranged over lock rod  27  face to face as shown in  FIG. 5  or a shim washer  33  may be placed between each pair of lock disks as shown in  FIG. 6 .  
         [0025]     The shim washers  33  have an outside diameter and an inside diameter that allow them to rotate freely inside the housing  31  and on lock rod  27 . The shim washers  33  are made from a material dissimilar to the lock disks  28  and  29  and aid in preventing galling between lock disks  28  and  29 . Plastic washers  34  transmit clamping force to the lock disks  28  and  29  and shim washers  33  as well as space the chest support brackets  24  away from the housing  31  to prevent scraping when the chest support brackets  24  are moved.  
         [0026]     The chest support brackets have a slot in them that allows them to slide over lock rod  27  but not rotate relative to lock rod  27 . Clamp plates  26  are prevented from rotating about lock rod  27  by their close fitting rectangular hole and they have a bent portion that bears on the edge of chest support brackets  24 . The bent portion of clamp plate  26  acts as a cam to force lock rod  27  and chest support bracket  24  tightly together when clamping pressure is applied, thus eliminating play between the brackets and rod. Pin  30  is pressed into lock rod  27  and transmits clamping force to clamp plate  26  when locking lever  25 , which is pivotally connected to the other end of lock rod  27 , is in the locked position as shown in  FIG. 6 . Locking lever  25  has a cam shape that allows movement of the lever to apply or release clamping force to clamp plates  24 , chest support brackets  24 , plastic washers  34 , shim washers  33  (optional), inner lock disk  28  and outer lock disks  29 . When clamping pressure is applied to inner and outer lock disks  28  and  29  friction prevents them from rotating relative to one another which in turn prevents lock rod  27  from rotating relative to housing  31 . Furthermore the friction between clamp plates  26  and chest support brackets  24  will prevent the chest support brackets  24  and chest support  13  attached to it from sliding or rotating relative to housing  31  and hence seat  14 . When the clamping force is released by moving locking lever  25  to the unlocked position all friction forces are reduced to the point that chest support  13  may be easily rotated or slid up and down relative to seat  14 .  
         [0027]     Face rest  11  is attached to chest support  13  such that it may be slid longitudinally in the plane of the chest support  13  closer to or further from chest support  13 . Face rest  11  may also be rotated about point  43  by operating locking lever  42 . The adjustment mechanism of face rest  11  is described in further detail in U.S. Pat. No. 5,427,436 and U.S. patent application Ser. No. 09/599,290, filed Jun. 21, 2000 both of which are hereby incorporated by reference in their entirety.  
         [0028]      FIG. 7  shows an alternative type of lock disks  60  and  61  which serve the same function as lock disks  28  and  29  shown in  FIG. 6 . Inner lock disks  60  and  60   a  have a square-shaped protrusion that fits into the inside of square housing  31  thereby preventing rotation of these lock disks relative to main rail  15 . The outer surface of lock disks  60  shown in  FIG. 8  has concentric tapered grooves  69 , which mate with concentric tapered tongues on lock disks  61 . Lock disks  60   a  and  61   a  are similarly configured. Outer lock disks  61  and  61   a  each have a rectangular protrusion that fits slidably into the slots on chest support brackets  24  and  24   a  respectively. Thus outer lock disks  61  and  61   a  are prevented from rotating relative to the chest support brackets and hence chest support  13 . Lock rod  62  is pivotally attached to cam lever  67  by pin  68 . Lock rod  62  runs through washer  64   a,  spacer  63 , the slot in bracket  24   a,  lock disks  61   a  and  60   a,  housing  31 , lock disks  60  and  61 , the slot in bracket  24 , plastic washer  65  and washer  64 . Nut  66  is threaded onto lock rod  62  and is adjusted to provide an appropriate clamping force to the components the rod runs through when cam lever  67  is in the locked position as shown in  FIG. 7 . When clamping pressure is applied by cam lever  67  the frictional forces between the tapered tongues and grooves of the mating lock disks prevent them from rotating relative to each other and hence prevent chest rest  13  from rotating relative to main rail  15 . The tapered shape of the tongues and grooves allows a smaller clamping force to result in a greater frictional force similar to the action of a cone clutch. The frictional force between the lock disks  61   a  and  61  and the brackets  24   a  and  24  prevent the brackets from sliding longitudinally relative to the disks when the clamping pressure is applied. Thus when the cam lever is in the locked position chest support  13  is prevented from rotating or sliding relative to main rail  15 . When the cam lever is moved to the unlocked position, the clamping force is reduced to the point where frictional forces may be easily overcome and chest support  13  may be rotated or slid longitudinally relative to main rail  15 .  
         [0029]     Alternate chair designs are shown in the Appendix attached hereto.  
         [0030]     Although the invention has been disclosed in its preferred forms, the specific embodiments thereof as disclosed and illustrated herein are not to be considered in a limiting sense, because numerous variations are possible. Singular terms used herein do not preclude the use of more than one of the associated element, and embodiments utilizing more than one of a particular element are within the spirit and scope of the invention. Applicant regards the subject matter of his invention to include all novel and nonobvious combinations and subcombinations of the various elements, features, functions, and/or properties disclosed herein. The following claims define certain combinations and subcombinations of features, functions, elements, and/or properties that are regarded as novel and nonobvious. Other combinations and subcombinations may be claimed through amendment of the present claims or presentation of new claims in this or a related application. Such claims, whether they are broader, narrower, equal, or different in scope to the original claims, also are regarded as included within the subject matter of applicant&#39;s invention.