Patent Abstract:
A foot support and abduction assembly includes an abductor configured for pivotal attachment proximate a foot end of a maternity bed. The foot support is configured for locating in a stowed position below the abductor, and a calf support is attached to an undersurface of the foot support. An upright assembly has a first end that is secured to the abductor for longitudinal movement along a length of the abductor, a second end to which the foot support is movably mounted, and a locking mechanism for selectively securing the upright assembly in one of a plurality of positions along the length of the abductor. The upright assembly is further configured for movement from a deployed position to a stowed position, and the locking mechanism is unlocked when the upright assembly is in the stowed position.

Full Description:
FIELD OF THE INVENTION 
   The invention relates to hospital beds and, more particularly, to a foot support and abduction assembly for a maternity bed, designed to ease the birthing process for both the mother and the medical personnel that are assisting her. 
   BACKGROUND OF THE INVENTION 
   An example of a foot support and abduction assembly can be found in U.S. Pat. No. 5,926,878, wherein the foot support and abduction assembly are mounted proximate a leg-foot section of a maternity bed. The foot support is rotatably mounted to an upright support and is rotatable from a first, use position to a second position wherein a leg support mounted on the back of the foot support is deployed to a use position. The upright support is rotatably and slidably mounted to an abductor and is rotatable from the upright, use position to an under-bed stowed position. The abductor is rotatably mounted to the maternity bed. Each movement of one of these elements requires release of a locking mechanism configured to secure the element in a selected position. Each release for a locking mechanism and movement of an element requires a two-handed operation by the attendant. 
   When the upright support, with attached foot support, is in the under-bed, stowed position, it has been found advantageous to have the sliding connection between the abductor and the upright support unlocked so that the upright support can be moved easily, or will give way if struck by hospital equipment or attendants. The attendant must remember to unlock the sliding mechanism when stowing the upright support. 
   It would be advantageous to provide integrated locking mechanisms for each element of the foot support and abduction assembly configured for one-handed unlocking and moving of the element by the attendant. It would be further advantageous to provide an automatic unlocking of the upright support sliding mechanism when in the stowed position. 
   SUMMARY OF THE INVENTION 
   A foot support and abduction assembly includes an abductor configured for pivotal attachment proximate a foot end of a maternity bed. The foot support is configured for locating in a stowed position below the abductor, and a calf support is attached to an undersurface of the foot support. An upright assembly has a first end that is secured to the abductor for longitudinal movement along a length of the abductor, a second end to which the foot support is movably mounted, and a locking mechanism for selectively securing the upright assembly in one of a plurality of positions along the length of the abductor. The upright assembly is further configured for movement from a deployed position to a stowed position, and the locking mechanism is unlocked when the upright assembly is in the stowed position. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a maternity bed foot support and abduction assembly according to the invention; 
       FIG. 2  is a perspective view according to  FIG. 1  with an attached calf support assembly; 
       FIG. 3  is a perspective view of the abduction assembly according to  FIGS. 1–2 ; 
       FIG. 4  is an exploded perspective view of the abduction assembly of  FIG. 3 ; 
       FIG. 5  is a bottom view of the abduction assembly of  FIGS. 3–4 ; 
       FIG. 6  is a bottom view of the abduction assembly according to  FIGS. 3–5  with gear rack installed; 
       FIG. 7  is a perspective view of the foot support and abduction assembly according to  FIGS. 1–6 ; 
       FIG. 8A  is a partial cut-away side view of the foot support and abduction assembly according to  FIGS. 1–7  in a locked position; 
       FIG. 8B  is an enlarged detail view according to  FIG. 8A ; 
       FIG. 9A  is a partial cut-away side view of the foot support and abduction assembly of  FIGS. 1–8  in an unlocked position; 
       FIG. 9B  is an enlarged detail view according to  FIG. 9A ; 
       FIG. 10  is a partial cut-away perspective view of an upright assembly for the foot support of  FIGS. 1–9 ; 
       FIG. 11  is a partial cut-away side view of a handle of the upright assembly of  FIG. 10 ; 
       FIG. 12  is a partial cut-away end view of the upright assembly of  FIGS. 10–11 ; 
       FIG. 13  is a partial cut-away side view of the upright assembly of  FIGS. 10–12 ; 
       FIG. 14  is a partial cut-away plan view of the upright assembly of  FIGS. 10–13  with the foot support in a locked position; 
       FIG. 15  is a partial cut-away plan view of the upright assembly of  FIGS. 10–14  with the foot support in an unlocked position; 
       FIG. 16  is a partial cut-away end view of the upright assembly according to  FIG. 15 ; 
       FIG. 17  is a partial cut-away side view of the upright assembly according to  FIGS. 15–16 ; 
       FIG. 18  is a partial cut-away end view of the upright assembly of  FIGS. 10–17  with the foot support in a second deployed position; 
       FIG. 19  is a partial cut-away side view according to  FIG. 18 ; 
       FIG. 20  is a partial cut-away end view of the upright assembly according to  FIGS. 10–19  with the upright assembly in a locked position; 
       FIG. 21  is a partial cut-away end view of the upright assembly according to  FIGS. 10–20  with the upright assembly in an unlocked position; 
       FIG. 22  is a partial cut-away perspective view of the upright assembly according to  FIG. 21 ; 
       FIG. 23  is a partial cut-away side view of the abduction assembly of  FIGS. 1–22  with the upright assembly in a stowed position; 
       FIG. 24  is a perspective view of a calf support for attachment to the foot support of  FIGS. 1–23 ; 
       FIG. 25  is an exploded perspective view of the calf support of  FIG. 24 . 
       FIG. 26  is a partial cut-away end view of the calf support of  FIGS. 24–25  in an unlocked position; and 
       FIG. 27  is a partial cut-away end view of the calf support of  FIGS. 24–26  in a locked position. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Certain terminology will be used in the following description for convenience and reference only, and will not be limiting. For example, the words “upwardly”, “downwardly”, “rightwardly” and “leftwardly” will refer to directions in the drawings to which reference is made. The words “inwardly” and “outwardly” will refer to directions toward and away from, respectively, the geometric center of the arrangement and designated parts thereof. Said terminology will include the words specifically mentioned, derivatives thereof, and words of similar import. 
   Referring to  FIG. 1 , a maternity bed foot support and abduction assembly  10  is illustrated. The maternity bed foot support and abduction assembly  10  comprises a left abductor  15  and a right abductor  20 , each pivotally attached to a respective stanchion  25 ,  30  formed as part of a bed foot lift casting  35  (shown in phantom). The bed foot lift casting  35  is configured for mounting to a foot end of a maternity bed (not shown). The bed foot lift casting  35  further includes a pair of integrally formed foot end support mounts  40 ,  45  configured for attaching a removable foot section of the maternity bed as disclosed in U.S. patent application Ser. No. 11/004,703, entitled “PATIENT SUPPORT APPARATUS WITH REMOVABLE FOOT SECTION”, filed Dec. 3, 2004, incorporated herein by reference. 
   An upright assembly  50 ,  55  is pivotally attached to each of the abductors  15 ,  20  and pivotally supports a foot support  60 ,  65 . As shown in  FIG. 1 , the upright assemblies  50 ,  55  are configured to pivot from an upright use orientation to a stowed orientation (shown in phantom) under the respective abductor  15 ,  20 . 
   Further description of the maternity bed foot support and abduction assembly  10  will refer in detail to the right abductor  20  and pivotally supported upright assembly  55  and foot support  65 . It is to be understood that the details of construction also apply to the left abductor  15  and associated upright assembly  50  and foot support  60 , reversed as necessary for operating on the opposite side of the maternity bed. 
   Referring to  FIG. 2 , a calf support assembly  70  is mounted to a reverse side  75  of the foot support  65 . The calf support assembly  70  includes a mounting housing  80 , a locking handle  85 , a phenolic ball  90 , a stanchion  95  and a calf support  100 . The calf support  100  is configured for swivel adjustment relative to the housing  80 . As will be further described below, the foot support  65  is pivotally mounted about a pivot axis  105  from a first position shown in  FIG. 2 , wherein the foot support  65  is directed toward a patient in the maternity bed, and a second position (not shown) wherein the foot support  65  is rotated toward the patient to present the calf support assembly  70  for use. In the remaining illustrations, the calf support assembly  70  has been omitted for clarity. 
   Referring to  FIGS. 3–5 , the abductor  20  is pivotally mounted to the stanchion  30  of the bed foot lift casting  35  about a pivot axis  110 . The abductor  20  is mounted to the stanchion  30  by a pivot shaft  115  having a threaded section  120 . A pair of thrust bearings  125 ,  130  and washers  127 ,  132  are received on the pivot shaft  115  and threaded section  120 , and secured by a nut  135  to enable the abductor  20  to rotate freely on the stanchion  30 . The stanchion  30  further includes a ring gear  140  rotatably secured thereto having a plurality of teeth  145 . 
   Referring to  FIG. 5 , the ring gear  140  is shown received in a cylindrical recess  150  within a proximal end  152  of the abductor  20 . A latch member  155  having a plurality of teeth  160  is pivotally mounted by a pin  165  to the abductor  20 . A locking cam  170  pivotally mounted to the abductor  20  by a pivot pin  175  is biased by a spring  180  to force the latch member  155  into engagement with the ring gear  140 . The cam  170  is connected by a pull rod  185  to an abductor release handle  190  pivotally mounted to the abductor  20  by a pivot pin  192 . The abductor release handle  190  is positioned at a distal end  194  of the abductor  20 . 
   Referring to  FIG. 6 , actuation of the handle  190  draws the locking cam  170  away from the latch member  155 . A spring  195  then draws the latch member  155  away from the ring gear  140  so that the teeth  145  of the ring gear  140  are no longer engaged with the teeth  160  of the latch member  155 . With the teeth  145 ,  160  disengaged, the abductor  20  is free to pivot about the axis  110  on the stanchion  30 . The springs  180 ,  195  are selected so that when the handle  190  is released, the spring  180  will overcome the spring  195  to urge the latch member  155  into engagement with the ring gear  140 . 
   The abductor  20  further includes a rack assembly  200  including a longitudinal rack  205  having a plurality of teeth  210 . The rack assembly further includes a pair of longitudinal tracks  215 ,  220 . The rack assembly  200  is secured to the underside of the abductor  20  by a bottom cover  225 , secured by a plurality of fasteners  230 . The rack assembly  200  is configured for slidably receiving the upright assembly  55  ( FIG. 7 ). The rack section  205  is secured to the rack assembly  200  by a pair of fasteners  211 ,  212  and a pair of pins  213 ,  214  ( FIG. 8A ). 
   Referring to  FIGS. 8A–8B , a partial cut-away view of the abductor  20  and upright assembly  55  is illustrated. The upright assembly  55  is slidably mounted to the abductor  20  and the rack assembly  200  by a pair of plates  235 ,  240 . Plates  235 ,  240  include flanges  245 ,  250  (see  FIG. 12 ) for straddling the rack  205 . A mounting assembly  255  is fixed between the plates  235 ,  240  for engaging the tracks  215 ,  220  and the rack  205 . 
   The mounting assembly  255  includes a locking arm  260  pivotally mounted by a pin  265  and including a plurality of teeth  270  configured for engaging the teeth  210  of the rack  205 . The locking arm  260  is held upwardly and in engagement with the rack  205  by a cam wedge  275  having a locking projection  280 . The cam wedge  275  is mounted on cam wedge rods  282  and is urged into a locked position of the locking arm  260  by a spring  285  bearing between the cam wedge  275  and the side plate  235 . 
   Referring to  FIGS. 9A–9B , to disengage the locking arm  260 , the cam wedge  275  must be drawn to the right against the bias of the spring  285 . As the cam wedge  275  is drawn to the right, the back surface  292  of the locking arm  260  rides down the canted upper surface  280  of the cam wedge  275 , permitting the locking arm  260  to disengage from the rack  205 . The cam wedge rods  282  are drawn to the right against the bias of spring  285  by a lever arm  295  pivoting about a pin  300 . A distal end  305  of the lever arm  295 , concealed within housing  307 , is engaged by a cable  310  for drawing the distal end  305  to the left and pivoting the lever arm  295  about the pin  300 . A proximal end  312  of the lever arm  295  is shifted to the right and bears against snap rings  314 , drawing the cam wedge rods  282  and the cam wedge  275  to the right. With the locking arm  260  disengaged from the rack  205 , the upright assembly  55  is free to translate longitudinally on the abductor  20 . 
   Referring now to  FIGS. 10–11 , the cable  310  is actuated by a handle assembly  315  received in the housing  320  of the upright assembly  55 . The handle assembly  315  includes an oblong frame  325  having a first handle  330  and a second handle  335  each pivotally attached by a pin  340 ,  345  to a respective upper corner  350 ,  355  of the oblong frame  325 . Upper lever portions  360 ,  365  of the first and second handles  330 ,  335  are urged apart by a compression spring  370 . This urges a lower lever portion  375  of the first handle  330  and a lower lever portion  380  of the second handle  335  together at a lower extent  385  of the frame  325 . An end of the cable  310  is secured to the lower lever portion  375  of the first handle  330  and a sheath  390  of the cable  310  is affixed to the lower lever portion  380  of the second handle  335 . As an operator squeezes either the first handle  330  or the second handle  335 , the separation distance between the lower lever portion  375  of the first handle  330  and the lower lever portion  380  of the second handle  335  increases, forcing the cable  310  to be retracted within the sheath  390 . As a consequence, the distal end  305  of the lever arm  295  is drawn in by the cable  310 , thereby releasing the lock arm  260  to permit the longitudinal translation of the upright assembly  55  on the abductor  20 . 
   Referring now to  FIGS. 12–19 , the foot support  65  is pivotally mounted on a pivot shaft  400  about the pivot axis  105  to an upper extent  402  of the upright assembly  55 . The upright assembly  55  includes a projecting wedge portion  405  (See also  FIG. 10 ) surrounding pivot shaft  400 , and a corresponding gap portion  407 . The foot support  65  includes a wedge portion  410  complementary to the wedge portion  405  for allowing a restricted rotation of the foot support  65  about the pivot shaft  400 . The upright assembly further includes a foot support locking pin  415  extending into the region about the wedges  405 ,  410  and configured for locking the wedge  410  in one of two distinct positions. 
   In  FIG. 13 , the foot support  65  is locked in a foot-support-use position with the wedge portion  410  trapped in an upper extent  417  of the gap portion  407  between the wedge portion  405  and the locking pin  415 . As shown in  FIGS. 15–17 , the pin  415  is retracted allowing the wedge  410  of the foot support to travel freely in the gap portion  407  around the wedge  405 . As shown in  FIG. 19 , the wedge  410  is locked in a lower extent  418  of the gap portion  407  around wedge  405  by the extended foot support locking pin  415 . The locking pin  415  is urged into the extended position by a spring  420 . The locking pin  415  is retracted by an operator depressing a push button  425  positioned on an outer face  427  of the upright assembly  55 . 
   The push button  425  is pivotally connected to a first end  430  of a toggle link  435  that is pivotally mounted in the upright assembly  55  by a pivot pin  440 . A second end  445  of the toggle link is pivotally connected to an end of the locking pin  415 . As best illustrated in  FIGS. 14–15 , depressing the push button  425  forces the pin  415  to retract from engagement with the wedges  405 ,  410 , thereby freeing the foot support  65  to rotate about the pivot axis  105 . 
   Referring now to  FIGS. 20–22 , the upright assembly  55  is pivotally mounted to a hub  460  affixed to the side plates  235 ,  240 . The upright assembly  55  is maintained in an upright position by a pin  465  slidably mounted in the upright assembly  55  being received in an aperture  470  of the hub  460 . The pin  465  is retractable from the aperture  470  of the hub  460  by operation of a stow-lever handle  475  and stow link  480 . The stow link  480  is urged in a counterclockwise direction about a pivot pin  482  by a spring  485  mounted on a foot rotation pin  490  urging an upper end  492  of the stow link  480  to the left. A lower end  495  of the stow link  480  thereby urges the pin  465  into the aperture  470  of the hub  460 . The pin  465  is drawn from the aperture  470  by an operator pulling on the stow-lever handle  475  to shift the lower end  495  of the stow link  480  to the left. 
   In order for the stow lever handle  475  to draw the stow link  480  in a clockwise direction against the urging of the spring  485 , the foot rotation pin  490  must be translated to the right. As shown in  FIG. 22 , the foot support  65  must be in a position wherein a foot rotation pin aperture  500  is in alignment with the foot rotation pin  490 . The position of the foot support  65 , hereinafter referred to as the stow position, is the forward position wherein the foot support  65  is accessible by the patient. With the foot rotation pin  490  in alignment with the aperture  500 , the stow link  480  can rotate about the pivot pin  482 , urging the foot rotation pin  490  into the aperture  500 . The lower end  495  of the stow link  480  draws the pin  465  out of the aperture  470  of the hub  460 . With the pin  465  extracted from the aperture  470 , the upright assembly  55  is free to rotate about the hub  460 . As the upright assembly  55  is rotated, the operator will release the handle  475  so that pin  465 , under the urging of the spring  485 , will bear against the surface of the hub  460 . As the upright assembly  55  rotates approximately 180 degrees, the pin  465  will engage a recessed stop/detent  507  in the surface of the hub  460 . The stop/detent  507  prevents the upright assembly  55  from over-rotating, and further resists inadvertent rotation of the upright assembly  55  toward the deployed position. 
   Referring to  FIG. 23 , the upright assembly  55  is rotated to a stowed position underneath the abductor  20 . As the upright assembly  55  is rotated to the stowed position of  FIG. 23 , a cam feature  510  of the upright assembly  55  acts against a tab  515  projecting from the cam wedge  275 . As the upright assembly  55  is rotated to the stowed position, the cam feature  510  rides against the tab  515  on the cam wedge  275  and forces the cam wedge  275  against the bias of the spring  285 , allowing the locking arm  260  to disengage from the rack  205 . The upright assembly  55  is thereby released for longitudinal movement on the rack  205  automatically when the upright assembly  55  is placed in the stowed position underneath the abductor  20 . 
   The calf support assembly  70  is illustrated in  FIGS. 24–27 . The calf support  100  is constructed of a thermoformed insert  101  and a urethane foam over-molded cover  102 . The insert  101  is secured to the stanchion  95  by a plate  103  and fastener  104 . This assembly is then placed in a mold for application of the urethane foam over-molded cover  102 . The cover  102  is sealed against fluids and formulated for compatibility with cleaning solutions. The stanchion  95  of the calf support  100  is secured to the phenolic ball  90  by a threaded rod  525 . A sleeve  530  is slidably received in the calf support housing  80 . The sleeve  530  includes a cup  535  having machined grooves  540  therein. The phenolic ball  90  is then received in the cup  535  of the sleeve  530  within the housing  80 . A locking ring  545  is then placed over the phenolic ball  90  and a retaining ring  530  is inserted into a groove  555  in the housing  80  to retain the assembly in the housing  80 . The handle  85  includes a threaded portion  560  that is received in a threaded aperture  565  of the housing  80 . 
   As best shown in  FIGS. 26–27 , the phenolic ball  90  is free to rotate or swivel within the housing  80  in  FIG. 26 , but as the T-locking handle  85  is threaded into the housing  80 , it drives the sleeve  530  into the phenolic ball  90 . The phenolic ball  90  is then locked between the sleeve  530  and the locking ring  545  to lock the calf support  100  in a fixed position. 
   Operation 
   The foot support and abduction assembly  10  according to the invention are substantially configured for one-handed operation by an attendant. In order to rotate the abductor  20  about pivot axis  110 , an attendant need only grasp the distal end  194  of the abductor  20 , simultaneously grasping the handle  190  to release the locking arm  155  from the ring gear  140 . The abductor  20  is thereby free to rotate about the axis  110 . Upon release of the handle  190  by the attendant, the abductor  20  is locked in its newly adjusted position. 
   The upright assembly  55  is slidably mounted on the abductor  20 . In order to move the upright assembly  55  in a longitudinal direction on the abductor  20 , the attendant need only grasp one of the first handle  330  or the second handle  335 , thereby releasing the locking arm  260  and allowing the upright assembly  55  to slide longitudinally on the abductor  20 . Since the attendant need only grasp one of the handles  330 ,  335 , the attendant can move the upright assembly  55  while at the foot of the bed or at the head of the bed. 
   The foot support  65  is rotatable from a first position wherein the foot support  65  is available for use by a patient, and a second position wherein the calf support assembly  70  is presented to the patient. The foot support  65  is rotatable about the axis  105  and is released by an attendant depressing the push button  425 , placing the attendant in a convenient position for rotating the foot support  65 . 
   The upright assembly  55  is rotatably mounted to the abductor  20 , from an upright deployed position to an under-bed stowed position. The upright assembly  55  is released to rotate to the under-bed stowed position by an attendant pulling on the stow-lever handle  475 . While grasping the stow-lever handle  475 , the attendant&#39;s hand is in position to support the upright assembly  55  for lowering. Once the pin  465  has cleared the aperture  470  of the hub  460 , the attendant can release the handle  475  and, in a one-handed fashion, lower the upright assembly  55  to the stowed position. The upright assembly  55  will only rotate until the pin  465  reaches the stop/detent  507  of the hub  460 . As the upright assembly  55  is lowered to the stowed position, the cam feature  510  operates to shift the cam wedge  275 , thereby releasing the locking arm  260  to permit longitudinal movement of the upright assembly  55  on the abductor  20 . The attendant can thereby conveniently lower the upright assembly  55  and shift it longitudinally on the abductor  20  with one hand. 
   Although particular preferred embodiments of the invention have been disclosed in detail for illustrative purposes, it will be recognized that variations or modifications of the disclosed apparatus, including the rearrangement of parts, lie within the scope of the present invention.

Technology Classification (CPC): 0