Abstract:
A support mechanism ( 20 ) for mounting a wheelchair back to a wheelchair post including at least one generally horizontally extending support pin ( 30 ), the support mechanism ( 20 ) comprising a hanger arm ( 24 ) having a downwardly opening hook ( 26 ) defining an upper support point and a self-locking latch ( 34 ) pivotally mounting to the hanger arm ( 24 ), the latch defining a locking notch ( 40 ) and a stop notch ( 42 ), the latch ( 34 ) being pivotal between a locked position in which the latch locking notch ( 40 ) and the hook ( 26 ) define a substantially closed hole around the support pin ( 30 ) and an unlocked position in which the pin ( 30 ) is seated in the stop notch ( 42 ) such that the latch ( 34 ) is secured open so the hanger arm hook ( 26 ) can be connected to or removed from the wheelchair post support pin ( 30 ); the latch ( 34 ) is shaped and weighted such that the latch can be moved to the locked position under the force of gravity.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. provisional application Ser. No. 61/303,471, filed Feb. 11, 2010 and PCT/US2009/052677, filed Aug. 4, 2009, which claims benefit of U.S. provisional application Ser. No. 61/086,994 filed Aug. 7, 2008 and Ser. No. 61/097,574 filed Sep. 17, 2008 and International Application PCT/US2011/022883 filed Jan. 28, 2011 and published under International Publication No. WO 2011/100127, all of which are incorporated herein in their entirety by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The disclosure relates generally to mounting assemblies to secure wheelchair back supports to the canes of wheelchairs. In one aspect, the mounting includes a gravity-driven latch for attaching the mounting assembly to a support point or support post on the wheel chair canes. In a further aspect, the mounting assembly includes a mounting clamp support assemblies from which the support post extends. 
     Wheelchairs generally comprise a frame with surface engaging wheels, a seating surface and a back support. The frame usually is made from tubular steel or the like. The seat and back can be a more pliant or flexible material such as vinyl or canvas for example. The frame includes two spaced apart upright members behind the seat, sometime referred to as posts or canes. The back support usually is suspended in a generally vertical orientation between the canes. 
     In many cases the original back support does not provide sufficient or appropriate support, or is not positioned in between the wheel chair posts, to meet the seated user&#39;s specific physical needs or tastes. The user may replace the original equipment back support with another back support, for example a more versatile or adjustable back support or one that is more rigid or firmer. These back supports can be attached to the original equipment canes or the canes can be removed and the replacement back installed. 
     Known back rests and mounting assemblies for back rests are complex and do not always allow for simple adjustment of the back rest, for example, without a tool. They generally include a back and do not provide for a mounting assembly that can be used to mount different back supports between the wheel chair canes. Moreover, they generally have a number of different adjustment points that must be operated to vary the angular position, vertical position and horizontal position or location of the back relative to the seat. It would be advantageous, therefore, to have a mounting assembly for a wheelchair back that can be used with different backs, that can allow for adjustment of the back in a plurality of ways using a single adjustment point and that can be adjusted without the use of tools. 
     Also, most currently available mounting assemblies for the wheel chair back rests do not allow for attachment to wheelchair canes without a tool. Additionally, currently available mounting assemblies do not allow for the mounting assembly to be securely connected to the wheelchair support posts when the mounting assembly is not locked or fastened to the support posts. Therefore, it would be advantageous to have a mounting assembly for a wheelchair back that can be easily unlocked using one hand without a tool and that can be securely connected to support posts on the wheelchair canes even in an unlocked position. 
     The mounting clamps of wheelchair posts of the prior art generally do not provide multiple support locations for the mounting assembly in a single clamp. They generally require the use of multiple clamps per wheelchair post and multiple loose parts for each clamp. It would be advantageous to employ a clamp that can be manipulated with one hand, without tools, that comprises fewer loose parts that may become inconveniently disengaged or even lost. 
     BRIEF SUMMARY 
     A mounting assembly is provided including a support mechanism for mounting the wheelchair back to support posts extending substantially horizontally from the wheelchair canes. The support mechanism is operable without the use of tools, and allows for one-handed attachment of the wheelchair back to the support posts and one-handed removal of the wheelchair back from the support posts. The support mechanism can be engaged in a locked position by gravity and released into and secured in an unlocked position by lifting up on a handle. 
     In another aspect of the invention, the support mechanism includes a hanger arm having a hook at the upper end defining an upper support point and a self-locking latch pivotally mounting to the hanger arm. The hook is a downwardly opening hook. The latch defines a locking notch and is pivotal between a locked position in which the locking notch and the hanger arm hook define a substantially closed hole around the support post and an unlocked position such that the hanger arm hook can be connected to or removed from the support post. The latch is shaped and weighted such that the latch will move to the locked position around support posts under the force of gravity when the back is installed between wheelchair canes. The latch can be moved from the locked position to the open position without the use of a tool. The latch further comprises a handle member which is graspable and lifted up so as to pivot the latch from the locked position to the unlocked position. The body of the latch is orientated away from the wheelchair back and canes leaving more clearance for moving the seat back backwards between the canes. 
     In accordance with a further aspect of the support mechanism, the latch includes a second or stop notch positioned on the latch to be generally vertically aligned with the hanger arm hook when the latch is rotated up to the unlocked position. The stop notch engages the support post when the latch is lifted to an open position such that the hook still securely engages the support post against inadvertent removal of the wheelchair back when the latching mechanism is in the unlocked position. 
     A further aspect of the invention provides a ramp or camming surface on the latch that allows the latch to move to an open position when it is urged against the support posts and then rotate into a closed position around the post under its own weight to allow for simple, single handed attachment between the wheelchair canes. 
     In another aspect, a mounting clamp which is secured to the wheelchair canes and from which the support post extends is provided that is simple in construction, has fewer loose parts, that provides at least one support point, and that can be easily disassembled and adjusted to accommodate canes of various diameters with or without the use of a tool. The mounting clamp includes a mounting clamp block and an associated C-shaped band that is positioned around the wheelchair cane. The band has a first arm and a second arm. The first arm of the band is hingedly attached to a first end of a barrel pin that extends through aligned openings in the sides of the clamping block. The second arm includes an opening that seats the second end of the pin. A fastener, generally a set screw or adjustment bolt, is threadedly engaged through the clamping block and the pin. To attach the band to the cane the adjustment bolt is loosened and the second arm of the band is disengaged from the second end of the pin and swung open about the hinge. The mounting clamp block is positioned against the cane and the band is swung back around the cane and the second arm of the band is secured to the second end of the pin. The adjustment bolt is tightened until the pin draws the band toward the block to impinge the cane between the clamp block and band securing the mounting clamp to the cane. 
     In a further variation of the clamp assembly, the clamp assembly includes a second point of support. In accordance with this variation, the clamp assembly can include elongated extension member extending downwardly from the clamp block. The extension member has a forward surface shaped complimentary to, and which is flush with, the clamp block forward surface, such that the extension member lengthens the forward surface of the clamp block. The second support post is positioned at a lower end of the extension member, the second point of support comprising a second support post. In this embodiment, the clamp block includes a support post extending from one side. The clamp block includes a first side and a second side. The recited sides have complementary openings. A pin is positioned through the openings. The pin has a first or free end and a second end. A generally C-shaped flexible band having a first or free arm with an opening and a second arm that is hingedly attached to the second end of the pin. The clamp block includes and opening for threaded engagement of a fastener. There is a hole in the pin for threaded engagement of the fastener. The flexible band can be opened to secure to an object such as a wheelchair cane by pivoting the band about the hinge. The band is then pivoted back around and the free end of the pin is seated in the free arm of the band. Rotation of the fastener in the pin draws the band toward the block. 
     In accordance with a further aspect, a mounting clamp assembly is provided from which the support post extends. The mounting clamp assembly comprises a clamp block, a flexible band having a generally C shape defined by a first and second arm, a pin extending through the clamp block and a fastener. One arm of the band is hingedly attached to the pin at a point adjacent one side of the block and at the approximate midpoint of the pin. The free or opposite arm of the flexible band is secured to one end of the pin adjacent the opposite side of the clamp block. The clamp block has a rear surface defining a hole, a forward surface which is generally V-shaped, a first side surface and a second side surface. The first and second side surfaces of the clamp block have aligned openings. The pin extends through the openings in clamp block. The band is pivoted around the hinge and opened to be placed around a wheelchair cane or other object. The band can be pivoted back around the hinge and secured to the pin. The band thus extends around the forward surface of the clamp block to define a space between the clamp block forward surface and the band for the wheelchair cane. The pin has a bore in functional alignment with the hole in the rear surface of the clamp block. The fastener extends through the clamp block rear surface hole and is operatively engaged with the bore of the pin. At least one of the pin bore and the hole in the rear surface of the clamp block is threaded, such that rotation of the fastener in a first direction draws the band toward the forward surface of the clamp block to reduce the size of the space between the band and the clamp block forward surface in order to secure the wheelchair cane between the band and the forward surface of the clamp block; and rotation of the fastener in an opposite direction moves the band away from the forward surface of the block. The pin has a length greater than a width of the clamp block and extends beyond the point where the band arm is hingedly attached, such that the end of the pin extends beyond one of the side surfaces of the clamp block when the pin is received in the block to define the support post. 
     In another embodiment, one end of the clamp pin extends beyond one of the side surfaces of the clamp block when the pin is received in the block to define the support post. However, one arm of the band is hingedly attached to the clamp pin at the opposite end of the pin and adjacent the block. This embodiment of the clamp functions similarly to the previously described embodiment 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a rear perspective view of a wheelchair back attached to a pair of wheelchair canes with a pair wheelchair back mounting assemblies and one embodiment of an associated clamp assembly of the present invention; 
         FIG. 2  is a rear perspective view thereof with the wheelchair back mounting assemblies unlatched and the wheelchair back removed from the canes; 
         FIG. 3  is a rear perspective view of the wheelchair back mounting assemblies unlatched from another embodiment of associated clamp assemblies and the wheelchair back removed from the canes; 
         FIG. 4  is a side view of the wheelchair back with the mounting assembly fully engaged with a mounting clamp support post; 
         FIG. 5  is a side view of the wheelchair back with the mounting assembly in a partially engaged state with the mounting clamp support post; 
         FIG. 6  is a side view of the wheelchair back with the mounting assembly rotated to an open position to allow removal from the support posts; 
         FIG. 7  is a side view of the wheelchair back with the mounting assembly disengaged from the top support post and the wheelchair back tilted for removal of the mounting assembly from the bottom support post; 
         FIG. 8  is a side view of the wheelchair back with the mounting assembly disengaged from the top and bottom support posts; 
         FIG. 9  is an enlarged perspective view of another embodiment of a clamp and post assembly on a wheelchair cane employing a top and bottom support post, with the flexible band rotated to an open position; 
         FIG. 10  is an enlarged perspective view thereof with the flexible band rotated to a closed position; 
         FIG. 11  is a partially exploded view of the clamp and post assembly of  FIGS. 9 and 10 ; 
         FIG. 12  is a fully exploded view thereof. 
         FIG. 13  is a perspective view of one embodiment of a mounting clamp and support post assembly attached to a wheelchair cane; 
         FIG. 14  is an enlarged perspective view of the embodiment of the mounting clamp of  FIG. 13 ; 
         FIG. 15  is an exploded view thereof; 
         FIG. 16  is an enlarged view thereof showing the flexible band in a partially rotated position; 
         FIG. 17  is a top plan view of another embodiment of a mounting clamp assembly and support post with the flexible band in rotated to an open position; 
         FIG. 18  is a top plan view thereof with the flexible band rotated to a partially closed position; 
         FIG. 19  is a top plan view thereof with the flexible band rotated to a closed position; 
     
    
    
     DETAILED DESCRIPTION 
     The wheelchair mounting assembly and one embodiment of the clamp and mounting post assembly of the present invention are indicated by reference numerals  20  and  22  respectively in  FIGS. 1 and 2 . A mounting assembly  20  is attached to each side of a wheelchair back B. Wheelchair back B is positioned between wheelchair canes C 1  and C 2 . It will be appreciated from  FIG. 1  that one object of the wheelchair mounting assembly  20  is to provide means for mounting a wheelchair back B to the canes C 1  and C 2 . It will be noted that the mounting assemblies  20  on each side of the wheelchair back B are mirror images. The wheelchair back B can be of any acceptable construction and can employ a rigid back or shell and a pad or cushion on the front side to provide a comfortable resting area for a user of the wheelchair. 
     As an initial matter, mounting assembly  20  includes an adjustment apparatus, indicated generally by reference number  23 . Adjustment apparatus  23  allows for varying the position of the wheelchair back relative to the canes and the wheelchair seat. The construction and operation of the adjustment apparatus is described in detail in assignee&#39;s PCT/US2009/052677, filed Aug. 4, 2009, the disclosure of which is incorporated herein by reference. 
     Mounting assembly  20 , shown in detail in  FIGS. 1 through 8 , includes a hanger arm  24 . Hanger arm  24  includes a top support point, which in the illustrated embodiment is hook  26 . Hook  26  is sized and shaped to engage or hang on an upper support post  30 . Hanger arm  24  also includes a lower support point or fork  28 . Lower fork is sized and shaped to engage a lower support post, such as lower support post  32 . Hanger arm  24  includes a rounded midsection  33  that comprises part of the adjustment apparatus described in detail in PCT/US2009/052677. It will be noted that the described support posts  30  and  32  can be a component of a clamp and post assembly, such as clamp and post assembly  22  or another type of clamp and post assembly, such as clamp and post assembly  92 , shown in  FIG. 3 , of which representative examples will be described in detail hereinafter. 
     Mounting assembly  20  includes a latching mechanism  34 . Latching mechanism  34  includes a body section  36  that includes an arcuate opening  38 , a first or primary locking notch  40  and a second or stop notch  42 . A handle portion  44  extends from the body. It will be noted, particularly in  FIG. 3 , that the body and handle particularly the handle of the latching mechanism are orientated away from the wheelchair back. This is advantageous in that it allows the wheelchair back additional clearance to be moved backward between the canes, as described in PCT/US2009/052677. 
     In any event, latching mechanism  34  is rotatingly attached to the upper hook area of the hanger arm by a pivot pin  45 . A lug  46  extends into arcuate opening  38  to limit the rotation of the latching mechanism around the pivot pin. As best seen in  FIG. 4 , when the latching mechanism is in a closed or locked position hook  26  and first notch  40  encircle post  30  to securely attach the wheelchair back to the upper post. Correspondingly, fork  28  rests on lower support post  32 . Latching mechanism  34  can be easily installed on support posts, even with one hand. First, fork  28  is positioned on lower support post  32 . Wheelchair back B is moved toward upper post  30 . Latching mechanism  34  includes a camming surface  47  which abuts the support post. Minimal effort is required to move the latching mechanism toward the post so as to rotate the latching mechanism to an open position until post  30  seats in first notch  40 . Once the support post is in the first notch, the latching mechanism falls under its own weight so that notch  40  and hook  26  encircle post  30  to secure the hanger arm to the upper post. It will be appreciated that in an alternative design a spring or other similar structure can be interposed between the latching mechanism and the hook, for example, to bias the latching mechanism in a closed position. 
     To release the wheelchair back from the support posts, handle  44  is lifted and latching mechanism  34  rotates about the pivot point  45  as shown sequentially in  FIGS. 5 and 6 . When the latching mechanism is completely raised, and lug  46  is at the end of arcuate opening  38 , as shown in  FIG. 5 , upper support post  30  seats in second notch  42  such that the latching mechanism is held is a substantially vertical position. This is important since the latching mechanism would close under its own weight if the upper post were not seated in the second notch to secure the latch in an open position. Consequently, even with one hand a user can open the latch on one side of the back and then open the latch on the opposite side of the back. 
     It will be noted that if the embodiment included a spring between the latching mechanism and the hook sufficient force must be applied to overcome the biasing force of the spring. However, the biasing force of the spring would not be so great so as to dislodge post  30  from second notch  42 . 
     In any event, it will be noted that even with latching mechanism  34  disengaged wheelchair back B will not completely disengage from the canes, an important safety feature. Hook  26  remains suspended on upper post  30  and fork  28  remains engaged on lower post  32 . Although disengaged, latching mechanism  34  helps stabilize the back in this position due to the fact that upper post  30  is seated in second notch  42 . As best seen in  FIGS. 7 and 8 , once the latching mechanism is released and hook  26  is disengaged from the top post  30  on each side of the wheelchair back, the back can be lifted to disengage fork  28  from the lower post  32  to completely remove the wheelchair back B from between the canes. 
     Mounting post assembly  22  is shown in greater detail in  FIGS. 9 through 12 . In this embodiment, mounting post assembly includes a generally rectangular block  50  that includes an upper block segment  52  and a lower block segment  54  connected by an elongated body segment  56 . Block  50  can be constructed as a single piece from an appropriate, durable, lightweight material such as cast, extruded or machined aluminum, plastic or other appropriate material. Block  50  includes a first side wall  57 , a second side wall  58 , a rear wall  60  and a forward wall  62 . It will be noted that forward wall  62  has a substantially V-shaped cross-section creating indention  64 . There is an elongated hole or slot  66  in the first side wall of the upper block segment and a complementary elongated slot  68  in the second side wall of the upper block segment. There is a hole  70  in the rear wall. The hole can be threaded or smooth. 
     A barrel pin  72  extends through the elongated slots  66 ,  68 . Pin  72  includes a generally centrally placed threaded hole  74 , a pivot pin hole  75  at a first end and circumferential groove  76  in the surface of the second end. The mounting post assembly includes a flexible, generally C-shaped band  77 . Band  77  includes a first arm  78  and a second arm  80 . The first arm includes a pair of linearly aligned pin sleeves  82  and  84 . The second arm includes an elongated opening  85  that has a major width  85 A and a minor width  85 B. The first arm of band  77  is attached to a first end of pin  72  by a pivot pin  88  that extends through the pin sleeves  82  and  84  and engages hole  75  in the first end of the pin. A threaded fastener  90  extends through hole  70  and engages threaded hole  74  of the barrel pin  72 . As shown in  FIG. 8 , band  77  can be opened by rotating the band around the pivot pin  88 . The opened band allows the assembly to be attached to a wheelchair cane C 1 . The band is then pivoted back around the cane until the second end of pin  72  is engaged in opening  85  of the second arm of band  77  with circumferential groove  76  secured in the minor width  85 B of the opening  85  to secure the band in place. Fastener  90  then is rotated, urging the band toward block  50  until the assembly is tightly secured to the cane. The V-shaped cross-section of the forward wall allows the assembly to engage wheelchair canes or other posts of variable diameters. In the illustrated embodiment, upper post  30  extends laterally from the upper block segment and lower post  32  extends laterally from the lower block segment  54 . The mounting assembly of the present invention is secured to the upper and lower posts as previously described. 
       FIGS. 13 through 16  illustrate another embodiment of a mounting post assembly of the present invention, indicated generally by reference number  92 .  FIGS. 3 and 13  shows a mounting post assembly  92  attached to the upper end of a wheelchair cane C. Mounting post assembly  92  generally comprises a block  94  having a first side wall  96 , a second side wall  98 , a rear wall  100  and a forward wall  102 . Forward wall  103  has a substantially V-shaped cross-section defining an indentation which allows the block to seat securely against canes of various diameters. The first and second side walls include aligned, complementary elongated openings  104  and  106 , respectively. There is an opening or hole  108  in the rear wall. Assembly  92  further includes a post  110  having a first end  112  with a knob  114  and a second end  116  having a circumferential groove  118  formed in the surface. Post  110  includes a threaded hole  120  offset toward the second end and a pivot pin hole  122  at the approximate midpoint of the post. Post  110  extends through openings  104  and  106  of block  94 . 
     The mounting post assembly includes a flexible, generally C-shaped band  124 . Band  124  includes a first arm  126  and a second arm  128 . The first arm includes an elongated, open ended slot  127  and a pair of linearly aligned pin sleeves  130  and  132 . The second arm includes an elongated opening  134  that has a major width  134 A and a minor width  134 B. The first arm of band  124  is attached to the approximate midpoint of post  110  by a pivot pin  140  that extends through the pin sleeves  130  and  132  and engages hole  122  in the post. A threaded fastener  142  extends through hole  108  and engages threaded hole  120  of the post. As shown in  FIG. 15 , band  124  can be opened by rotating the band around the pivot pin  140 . Open ended slot  127  allows the band to rotate to an open position without abutting the post. The opened band allows the assembly to be attached to a wheelchair cane C 1 . The band is then pivoted back around the cane until the second end of post  110  is engaged in opening  134  of the second arm of band  124  with circumferential groove  118  secured in the miner width  138  of the opening to secure the band in place. Fastener  142  then is rotated, urging block  94  toward the cane until the assembly is tightly secured to the cane. 
       FIGS. 17 through 19  illustrate another embodiment of a mounting post assembly of the present invention, indicated generally by reference number  144 . Mounting post assembly  144  generally comprises a block  146  having a first side wall  148 , a second side wall  150 , a rear wall  152  and a forward wall  154 . The forward wall has a substantially V-shaped cross-section defining indention  155 . The first and second side walls include aligned, complementary elongated openings similar to those previously described in reference to block  94 . There is an opening or hole  160  in the rear wall. Opening  160  can be threaded or smooth. Assembly  144  further includes a post  162  having a first end  164  with a knob  166  and a second end  168 . Post  162  includes a threaded hole  170  offset toward the second end and a pivot pin hole (not seen) at the extreme second end. Post  162  includes at least one detent  174  on the surface at the approximate mid point. 
     The mounting post assembly includes a flexible, generally C-shaped band  178 . Band  178  includes a first arm  180  and a second arm  182 . The first arm includes a pair of linearly aligned pin sleeves  184 . Although not seen in the drawings band  178  is constructed similarly to band  124  previously describe, having a second arm with an elongated opening that has a major width and a minor width. The first arm  180  of band  178  is attached to the end of post  162  by a pivot pin  181  that extends through the pin sleeves and engages a hole in the post. A threaded fastener  182  extends through hole  160  and engages threaded hole  170  of the post. As shown in  FIGS. 17 and 18 , band  178  can be opened by rotating the band around the pivot pin  181 . The opened band allows the assembly to be attached to a wheelchair cane. The band is then pivoted back around the cane until the opening in the second arm of the band is secured around the post at detents  174  to secure the band in place. Fastener  182  then is rotated until the assembly is tightly secured to the cane. 
     It will be appreciated that in the various embodiments of the post mounting assemblies the pivotal connection of the flexible band to the barrel pin or posts serves an important purpose of eliminating loose parts that can become disengaged and dropped or even lost, which may be particularly burdensome for an individual confined to a wheelchair. It will be noted that a pair of mounting post assemblies  92  and  142  can be attached to a cane at an appropriate linear distance apart, as seen in  FIG. 3 , to allow the attachment of an attachment assembly of the present invention to an upper post and a lower post. 
     The foregoing description and accompanying drawings are intended to be illustrative only and should not be construed in a limiting sense.