Abstract:
A patient support apparatus includes a patient support having a first patient support deck, a removable section having a second patient support deck, the removable section being configured for movement to a first position wherein the removable section is coupled to the patient support, a second position wherein the removable section is adjacent to but spaced from the first position and a third position spaced apart from the patient support. A handle support mechanism is mounted on one of the patient support and the removable section. A handle is movably mounted on the handle support mechanism and is supported thereby for movement between a first handle position and a second handle position. The handle support mechanism is configured to facilitate movement of the handle from the first handle position toward the second handle position only when the removable section is oriented at and between the first and second positions.

Description:
FIELD OF THE INVENTION 
   The invention relates to a patient support apparatus with a removable foot section. In one of its aspects, the invention relates to a removable foot section provided with a positive locking mechanism provided with a convenient handle for use in attachment and removal of the removable foot section by an operator. 
   BACKGROUND OF THE INVENTION 
   A patient support apparatus with a removable foot section, also known in the field as a birthing bed, provides full support for a patient, namely an expectant mother in labor, until she is ready to give birth. Rather than move the mother to another bed that gives the doctor better access, the birthing bed is provided with a removable foot section. This removable foot section must be capable of ready detachment, but just as importantly must be positively secured to the main bed and incapable of inadvertent detachment. It would further be advantageous to provide a removable foot section with an operating mechanism that does not extend beyond the normal profile of the bed, and is intuitive to the operator in its method of operation. 
   SUMMARY OF THE INVENTION 
   A patient support apparatus includes a patient support having a first patient support deck, a removable section having a second patient support deck, the removable section being configured for movement to a first position wherein the removable section is coupled to the patient support, a second position wherein the removable section is adjacent to but spaced from the first position and a third position spaced apart from the patient support. A handle support mechanism is mounted on one of the patient support and the removable section. A handle is movably mounted on the handle support mechanism and is supported thereby for movement between a first handle position and a second handle position. The handle support mechanism is configured to facilitate movement of the handle from the first handle position toward the second handle position only when the removable section is oriented at and between the first and second positions. 
   In a further embodiment of the invention, a patient support apparatus comprises a patient support including a first patient support deck, a removable section having a second patient support deck, the removable section being configured for movement to a first position wherein the removable section is coupled to the patient support, a second position wherein the removable section is adjacent to but spaced from the first position and a third position spaced apart from the patient support. A sensing mechanism is configured for sensing a presence of the removable section at and between the first and second positions thereof. A latch recess mechanism is mounted on the patient support and configured to be engaged by the sensing mechanism in response to the removable section being moved from the third position toward the first position, the latch recess mechanism including at least one recess. A latch mechanism is mounted on the removable section and includes a latch member configured to move into the at least one recess only in response to the sensing mechanism sensing the presence of the removable section at the first position. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The purposes of the invention will be apparent to persons acquainted with apparatus of this general type upon reading the following specification and inspecting the accompanying drawings, in which: 
       FIG. 1  is a perspective view of a patient support apparatus with a removable foot section according to the invention; 
       FIG. 2  is a bottom perspective view of the patient support apparatus of  FIG. 1 ; 
       FIG. 3  is a partial cut-away view of the patient support apparatus of  FIG. 2 ; 
       FIG. 4  is a partial cut-away view of the removable foot section moving toward an attached position on the patient support apparatus; 
       FIG. 5  is a partial cut-away view of the removable foot section of  FIGS. 1-4  with a sensing link activated by a patient support apparatus latch mount; 
       FIG. 6A  is a bottom perspective view of the removable foot section of  FIGS. 1-5  with a secondary locking mechanism disengaged; 
       FIG. 6B  is an enlarged view of a handle pivot mechanism according to  FIG. 6A ; 
       FIG. 7  is a partial cut-away perspective view of the removable foot section of  FIG. 6 ; 
       FIG. 8  is a partial cut-away view of the removable foot section of  FIGS. 1-7  with the locking mechanism partially engaged; 
       FIG. 9  is a partial cut-away perspective view of the removable foot section of  FIGS. 1-8  with the locking mechanism fully engaged; 
       FIG. 10  is a cross-sectional view of a locking mechanism according to a second embodiment of the invention; 
       FIGS. 11-16  are cross-sectional views of the locking mechanism of  FIG. 10  sequentially illustrating the locking action of the mechanism; 
       FIG. 17  is a bottom perspective view of a removable foot section according to a further embodiment of the invention; 
       FIG. 18  is an enlarged cut-away view of a portion of the removable foot section of  FIG. 17 ; 
       FIG. 19  is a partial cut-away view according to  FIG. 18  with a latch mechanism partially engaged; 
       FIG. 20  is a partial cut-away view according to  FIGS. 18-19  with the latch mechanism engaged; 
       FIGS. 21-24  are perspective views of alternative handle configurations of the removable foot section of  FIGS. 1-9 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Certain terminology will be used in the following description for convenience in reference only and will not be limiting. The words “up”, “down”, “right” and left” will designate directions in the drawings to which reference is made. The words “in” and “out” will refer to directions toward and away from, respectively, the geometric center of the device and designated parts thereof. The words “proximal” and “distal” will refer to the orientation of an element with respect to the patient support apparatus. Such terminology will include derivatives and words of similar import. 
   Referring to  FIG. 1 , a patient support apparatus with a removable foot section  100  is illustrated. The patient support apparatus  100  includes a main bed  110  and a removable foot section  150 . 
   The main bed  110  includes a support base  115  to which is mounted a main bed patient support deck  116 . The support deck  116  supports a main bed pad or mattress  112  having an upper surface  113 . The main bed  110  further includes an anterior or perineal edge face  114  adapted for receiving the removable foot section  150 . 
   A pair of mounting brackets  118  ( FIGS. 1-3 ) is positioned distally from the anterior face  114  and is configured for mounting a pair of latch mounts  120  for securing the removable foot section  150  proximate the anterior face  114  of main bed  110 . The mounting brackets  118  can be configured as disclosed in commonly owned U.S. Pat. No. 7,127,756, which is hereby incorporated herein by reference. The removable foot section  150  can be supported by a pair of abductors as illustrated therein, for alignment of the removable foot section  150  with the latch mounts  120 . In the alternative, the removable foot section  150  and the abductors can be arranged to deliberately preclude support of the removable foot section  150  by the abductors, in order to force an operator to deliberately align the removable foot section  150  with the latch mounts  120 , and to avoid inadvertent placement of the removable foot section  150  adjacent the main bed  110  in a non-engaged condition. 
   Each latch mount  120  has a generally upwardly opening “C” shape and includes a distal or nose portion  128  incorporating an upwardly and inwardly directed catch  122 , a flattened central portion  126  and a raised proximal portion including an inwardly directed recess  124 . Referring further to  FIG. 2 , each latch mount  120  includes a mounting base  132  for mounting the latch mount  120  to the mounting bracket  118 . Each latch mount  120  further incorporates a pair of parallel opposing side channels  130  forming a narrowed center section or neck  129  for facilitating insertion of the latch mount  120  into the removable foot section  150  as will be further described below. 
   Referring to  FIGS. 1 and 2 , the removable foot section  150  includes a proximal end  162  and a concave distal end  164 . The removable foot section  150  further includes a pair of tubular side rails  156 , a proximal cross rail  160  and an arcuate distal cross rail  158 . The tubular side rails  156  include a proximal end  157 . A foot section patient support deck  154  is mounted to the rails  156 ,  158 ,  160 . The patient support deck  154  is further configured for supporting a foot section pad  152  having an upper surface  153 . When the removable foot section  150  is attached to the main bed  110 , the upper surface  153  of the foot section  150  will be contiguous with the upper surface  113  of the main bed pad  112 . 
   The removable foot section  150  further includes a brace  166  attached to and depending from the proximal cross rail  160  and the foot section patient support deck  154 . The brace  166  is configured to support the removable foot section  150  in a vertical orientation on a floor surface when the foot section  150  is removed from the main bed  110 . The removable foot section  150  is configured to stand, in the vertical orientation, on the brace  166  and the proximal end  157  of the side rails  156 . 
   At the proximal end  157  of the side rails  156 , each side rail  156  includes a mount-receiving slot  168  with a chamfered mouth  170 . A sleeve  224  is secured within the side rail  156  over the mount-receiving slot  168  by a fastener  225 . The mount-receiving slots  168  are adapted for receiving the latch mounts  120  in such a manner that the neck  129  of each latch mount  120 , formed by the side channels  130 , aligns with the respective mount-receiving slot  168  of the side rails  156 . The sleeve  224  is positioned within the side rail  156  for alignment with the recess  124  of the latch mount  120  as the latch mount  120  enters the side rail  156 . The chamfered mouth  170  of each mount-receiving slot  168  aids the operator in guiding the latch mounts  120  into the mount-receiving slots  168 . 
   The removable foot section  150  further includes a locking mechanism  180  for releasably locking the removable foot section  150  to the main bed  110 . As seen in  FIGS. 1-2 , the locking mechanism  180  presents an operator with a main U-shaped handle  182  and a U-shaped release lever  184  pivotally associated with the main U-shaped handle  182 . The handle  182  and release lever  184  are inverted “U”s straddling the removable foot section  150  in the form of an arch. Each depending leg of the handle  182  and release lever  184  terminate within a handle pivot assembly  186 . The handle pivot assembly  186  is pivotally mounted to a locking mechanism cam housing  188  depending from each side rail  156 . Each cam housing  188  is U-shaped, with each upstanding leg or wall of the cam housing  188  connecting to the tubular side rail  156  so that the cam housing  188  hangs directly beneath the side rail  156 . 
   Referring briefly to  FIGS. 6A-6B , the cover of the handle pivot assembly  186  has been removed to reveal that the release lever  184  is pivotally attached to the main handle  182  by a pivot pin  244 , and includes a distal portion  246  extending beyond the fulcrum formed by the pivot pin  244 . The main handle  182  is fixedly mounted to a double-D-shaped cam pin  232  which rotatably mounts the main handle  182  to the cam housing  188 . A spring-urged plate  239  having a central elongate slot  237  is slidably mounted on the cam pin  232 . The plate  239  includes a locking lug  240  extending inwardly toward the cam housing  188 , and adapted, under the urging of a spring  241 , for engaging one of a number of notches  242 ,  243  formed in the wall of cam housing  188 . In  FIGS. 6A-6B , the release lever  184  has been rotated about the pivot pin  244  so that the distal portion  246  of the release lever  184  has countered the urging of the spring  241  on the plate  239 , forcing the locking lug  240  out of the notch  242 . In  FIGS. 3-4 , the locking lug  240  is urged by the spring  241  into the notch  242 . 
   Referring now to  FIG. 3 , a partial cut-away view of the removable foot section  150 , the internal components of the locking mechanism  180  within one side rail  156  are illustrated. The handle pivot assembly  186 , the outer wall of the cam housing  188  and the side rail  156  have been removed to reveal the internal components. The configuration of the locking mechanism  180  of each side rail  156  is the same. In the following description, the components and function of only one side rail  156  will be described, but it is to be understood that the components and function apply to both side rails  156 . It is to be recognized that some portions of the handle pivot assembly  186  will need to be a mirror image of the other for attachment to the outside of the respective side rail  156 . 
   The locking mechanism  180  within the tubular side rail  156  includes a locking cam  230 , a carriage assembly  210  connected to the locking cam  230  by an elongate locking mechanism linkage  200 , and an elongate sensing link  190 . 
   The locking cam  230  is eccentrically mounted on the double-D-shaped cam pin  232  and is rotatably connected to the cam housing  188 . The locking cam  230  includes a lever arm  231  and a distally extending flat portion  234 . 
   The locking mechanism linkage  200  is pivotally connected at its distal end to the lever arm  231  of the locking cam  230  by a pivot pin  202 , and is pivotally connected at its proximal end to the carriage assembly  210  by a pivot pin  204 . 
   The carriage  210  is slidably received within the tubular side rail  156 . The carriage  210  carries a U-shaped pivotal locking arm  212 , the bight portion of the “U” forming a locking hook  214 . The legs  212 A (see  FIG. 3 ) of the “U” straddle the carriage  210  and are pivotally supported on the carriage  210  by a pivot pin  211 . The locking hook  214  is forced upward as a locking pin  220 , fixed to the respective side rail  156 , pivots the locking arm  212  about the pivot pin  211  by pressing against a distal portion of the locking arm  212 . 
   The elongate sensing link  190  is slidably carried within the tubular side rail  156  and includes a proximal end  192  and a distal end  194 . The sensing link  190  is spring-biased in a proximal direction by a spring  195  connecting the sensing link  190  to the carriage assembly  210 , forcing the proximal end  192  of the sensing link  190  toward the proximal end  157  of the side rail  156 . As shown in  FIGS. 3-4 , the distal end  194  of sensing link  190  is urged by the bias of the spring  195  against the locking cam  230  and under the flat portion  234 . 
   Operation 
   As shown in  FIGS. 1-5 , the main handle  182  is shown locked in an upright “carry” position. The arcuate distal end of the removable foot section  150  can be balanced against the operator&#39;s midsection while the operator carries the removable foot section  150  by the upright, locked main handle  182 . It will be intuitive to the operator that the carry handle must be moved from the upright “carry” position to a stowed position so as to not interfere with the use of the patient support apparatus. 
   Referring to  FIGS. 1-4 , the main handle  182  is prevented from rotating from its upright “carry” position by two mechanisms, the locking cam  230  and the spring-urged plate  239  (see  FIGS. 6A and 6B ). The handle  182 , the locking cam  230 , and the plate  239  are all rotatably fixed on the double-D-shaped cam pin  232 . The locking cam  230  is prevented from rotating due to the positioning of the distal end  194  of the sensing link  190  under the flat portion  234  of the locking cam  230 . The plate  239  is urged by the spring  241  so that locking lug  240  is received in the notch  242 . In order to rotate the handle  182 , both of these locking mechanisms must be released. 
   To releasably attach the removable foot section  150  to the main bed  110 , the removable foot section  150  must begin at a position removed from the anterior face  114 , with the upper surface  153  of the foot section pad  152  substantially co-planar with the upper surface  113  of the main bed pad  112 . This will align the bottom face of the side rails  156  and therefore the mount receiving slots  168  with the side channels  130  of the latch mounts  120 . The side rails  156  must also be aligned laterally with the latch mounts  120 . 
   As the removable foot section  150  is moved toward the main bed  110 , the nose end  128  of each latch mount  120  will enter a respective side rail  156  such that the side channels  130  will be received in the mount receiving slots  168 . Since the nose section  128  of the latch mount  120  is lower than the raised proximal portion of each latch mount  120 , the nose section  128  will clear the sleeve  224  mounted within each side rail  156  (see  FIG. 4 ). As each latch mount  120  enters each side rail  156 , the nose section  128  will contact the proximal end  192  of each sensing link  190 . 
   Further movement of the foot section  150  toward the main bed  110  will cause the nose section  128  to force the sensing link  190  against the bias of the spring  195 . As the sensing link  190  is displaced against the bias of spring  195 , the distal portion  194  of the sensing link  190  is forced clear of the flat portion  234  of the cam  230 . With the distal portion  194  of the sensing link  190  displaced, as shown in  FIGS. 5-9 , the flat  234  can now clear the distal portion  194  of sensing link  190  so that the cam  230  can rotate in a counter clockwise direction. 
   Before the handle  182  can be rotated, however, the secondary locking mechanism comprising the lug  240  within the notch  242  must be disengaged. In a natural and intuitive operation, aided by color-coding or instructional wording on the release lever  184 , the operator will squeeze together the release lever  184  and the main handle  182 . The release lever  184  is thereby rotated about the pivot pins  244 , causing the distal portion  246  of the release lever  184  to shift the plate  239  against the urging of spring  241  and extract the locking lug  240  from the notch  242  (see  FIGS. 6A-6B ). With the locking lug  240  out of the notch  242 , the double-D-shaped cam pin  232 , the locking cam  230 , the plate  239 , and the main handle  182  are free to rotate together relative to the cam housing  188 . With the removable foot section  150  still supported in the engaged position against the main bed by the operator&#39;s midsection, the operator can then draw the main handle  182  distally about the cam pin  232 , thereby engaging the locking mechanism  180  for securing the removable foot section  150  to the main bed  110 . 
   With particular reference to  FIG. 8 , as the cam pin  232  rotates with the main handle  182 , the lever arm  231  of the cam  230  draws the locking mechanism linkage  200  toward the distal end of removable foot section  150 , drawing the carriage assembly  210  with it. As the carriage assembly  210  traverses distally with respect to the locking pin  220 , the locking hook  214  is urged by sliding contact with the locking pin  220  into the central portion  126  of the latch mount  120  and then is drawn distally against the catch  122 . Further rotation of the cam  230  will result in the foot section  150  being drawn in toward the anterior face  114  of the main bed until the sleeve  224  is received in the recess  124  of the latch mount  120 . 
   The cam housing  188  includes a stop  236  positioned such that the flat portion  234  of the cam  230  reaches the stop  236  as the sleeve  224  is fully received in the recess  124  of the latch mount  120 . This coincides with the main handle  182  having rotated approximately 90 degrees so that it is substantially co-planar with the side rails  156 , and no longer interferes with the use of the bed. Upon release of the main handle  182  and the release lever  184  by the operator, the spring  241  acting on the plate  239  will urge the locking lug  240  inwardly to engage the notch  243  in the cam housing  188 . The notch  243  is positioned on the cam housing  188  to correspond to the main handle  182  being in the horizontal position. 
   The removable foot section  150  is thereby positively mounted to the main bed  110  until an operator proactively grasps the main handle  182  and the release lever  184  and moves the release lever  184  toward the main handle  182 , thence causing the locking lug  240  to be extracted from the notch  243 . The operator then rotates the main handle  182  in a clockwise rotation, reversing the above-described sequence to disengage the locking mechanism  180 . When main handle  182  reaches the upright position and the release lever  184  is released by the operator, the locking lugs  240  will enter the notches  242  under the urging of the springs  241  to lock the handle  182  in the upright position. The removable foot section  150  can thereafter be lifted away from the main bed  110 . The concave distal end  164  of the removable foot section  150  is configured for resting against the operator&#39;s midsection while the operator lifts the removable foot section  150  by the main handle  182 . With the concave distal end  164  resting against the operator&#39;s midsection, the center of mass of the removable foot section  150  is advantageously drawn closer to the operator, rendering the removable foot section  150  easier to lift and transport. 
   Second Embodiment of FIGS.  10 - 16   
   Referring now to  FIGS. 10-16 , a further embodiment of a locking mechanism  300  for a removable foot section for a patient support apparatus is illustrated. The mechanism  300  includes a plate-like latch mount  310  configured for mounting to a main bed comparable to the main bed  110  described above. The latch mount  310  includes a sensing link receiver  312 , a latch receiver/recess  314  and a catch  316 . 
   The removable foot section includes a rail  320  that is substantially rectangular in cross-section. A cross pin  322  is fixedly mounted near the proximal end of the rail  320 . A locking arm  330  is pivotally mounted to the rail  320  by a spring/locking arm pivot  332 . The locking arm  330  is pivotally linked to a spring arm  334  also pivoting about the spring/locking arm pivot  332  and biased in a counter clockwise direction (as shown in  FIG. 10 ) by a spring  328 . 
   The locking arm  330  includes a locking arm face  335  and is prevented from rotating through the contact of the locking arm face  335  with a sensing link nose  344 . The sensing link nose  344  is part of a sensing link  340  slidably mounted within the rail  320 . The sensing link  340  includes a longitudinal slot  352  for facilitating a relative movement to the spring/locking arm pivot  332  of the locking arm  330 . The sensing link  340  further incorporates a proximal slot/recess  342  for clearing the cross pin  322  of the cross rail  320 . 
   Referring sequentially to  FIGS. 10-15 , as the foot section is moved or pushed by the attendant proximally toward the main bed, the latch mount  310  enters the proximal end of rail  320  through appropriately provided slots as in the embodiment described above. The first positive engagement occurs between the sensing link receiver  312  of the latch mount  310  and the sensing link nose  344  of the sensing link  340 . 
   As the sensing link nose  344  contacts and is displaced distally by the latch mount  310  as shown in  FIGS. 12-13 , the sensing link  340  is displaced distally with respect to the rail  320  as the rail  320  continues its movement toward engagement with the latch mount  310 . As the cross pin  322  becomes fully engaged with the latch receiver/recess  314  of the latch mount  310 , the sensing link nose  344  is pushed by the latch mount  310  past the locking arm face  335  of the locking arm  330 . When the sensing link nose  344  has cleared the locking arm face  335 , the locking arm  330  is biased counter clockwise by the spring  328 , forcing the locking hook  336  mounted to the locking arm  330  into the catch  316  of the latch mount  310 . The foot section is thereby locked with the main bed in a positive manner. 
   Referring to  FIG. 16 , a release mechanism is disclosed whereby a release handle  350  is slidably mounted to the side rail  320 . The release handle  350  includes two angled slots  358 ,  360  configured to ride on laterally extending pins  362 ,  364  secured to the frame  320 , so that as the release handle  350  is depressed (or lifted), the angled slots  358 ,  360  will cause the release handle  350  to be drawn upward and to the right. A link arm  354  is pivotally mounted to the sensing link  340  by a pivot pin  348 . The link arm  354  includes a second pin  356  configured to engage the release handle  350 , and is supported by the laterally extending pin  362 . When the sensing link  340  is in the non-engaged position, i.e. fully extended to the left, the link arm  354  is also drawn to the left. With the link arm  354  drawn to the left, the second pin  356  is drawn into a longitudinal slot  353  formed in the release handle  350 . Therefore, if the release handle is depressed when the sensing link  340  is not engaged by the latch mount  310 , the second pin  356  can slide freely in the slot  353  and the sensing link  340  is not affected. With the sensing link  340  displaced to the right by engagement with the latch mount  310 , the link arm  354  is also displaced to the right, as shown in  FIG. 16 . This shifts the second pin  356  out of the slot  353  and into a position to be engaged by a recess wall  355  formed on the release handle  350 . As the release handle  350  is depressed, the second pin is engaged by the recess wall  355 , causing sensing link  340  to be further displaced to the right. As sensing link  340  is displaced distally, a locking arm retracting pin  349  mounted on the sensing link  340  will bear against a locking arm retractor  338 , acting against the bias of the spring  328  and causing the locking arm  330  to rotate clockwise as shown in  FIG. 16 . With locking hook  336  withdrawn from the catch  316 , the foot section can be withdrawn distally from the main bed. As the foot section is withdrawn, the handle  350  can be released so that the sensing link nose  344  can engage the locking arm face  335  under the urging of the spring  328 . 
   Third Embodiment of FIGS.  17 - 20   
     FIGS. 17-20  disclose a further embodiment of the patient support apparatus with a removable foot section  450  according to the invention. A pair of latch mounts  420  are provided, mounted to a main bed as described above in the first embodiment. The latch mounts  420  comprise an upwardly directed “C” shape, having an inwardly directed proximal recess  424  and an inwardly directed distal catch  422 . The latch mounts  420  further include an arcuate nose portion  428 . 
   The removable foot section  450  includes a foot section patient support deck  454  supported by a pair of longitudinal side rails  456  and cross rails  458 ,  460 , and a pad  452  supported by the support deck  454 . The side rails  456  each include a proximal slot  468  having a mouth  470  for receiving each of the latch mounts  420 , as in the first embodiment 
   The removable foot section  450  further includes an attachment and locking mechanism  480 . The locking mechanism  480  includes a handle  482  in the form of an inverted “U”. Each of the legs of the handle  482  are connected to a cam bracket  530 . Each cam bracket  530  is pivotally mounted to one of the side rails  456  by a pivot pin  532 . The cam bracket  530  includes an internal cam plate  534  pivotally connecting the cam bracket  530  to a connecting link  500  by a pivot pin  502 , an external mounting plate  536  for mounting the handle  482  and a back plate  538  serving as a rotation stop of the cam bracket  530  with respect to the side rail  456 . Each connecting link  500  is further pivotally connected to a carriage  510  and sensing link  490 . The connecting link  500  is connected to the carriage  510  by a pin  504  passing through a slot (not shown) in the side rail  456 . The slot enables proximal-distal movement of the pin  504  and the carriage  510  within the side rail  456 . The sensing link  490  pivots about the pin  504 . 
     FIGS. 18 and 19  are enlarged cut-away views showing the carriage  510 , the sensing link  490 , and a locking arm  512 , which can be of a U-shape straddling the carriage  510  with the bight portion forming a locking hook  514 . The carriage  510  is slidably received in the side rail  456 , and pivotally mounts the locking arm  512  about a pivot pin  506 . The locking arm  512  is held in a raised position by a locking pin  520  after the same fashion as the first embodiment. 
   Referring specifically to  FIG. 18 , the sensing link  490  includes a catch  496  for receiving the locking pin  520 . In the position shown in  FIG. 18 , the catch  496  has received the locking pin  520  therein, which prevents the carriage  510  from moving distally within the side rail  456 . The handle  482  is also thereby prevented from rotating distally about pivot pin  532 . 
   Referring to  FIG. 19 , the removable foot section  450  has been moved proximally toward the latch mount  420  so that the arcuate nose portion  428  of the latch mount  420  has engaged the leading edge  492  of the sensing link  490 . This causes the sensing link  490  to pivot about the pin  504 , disengaging the catch  496  from the pin  520 . This frees the carriage  510  to slide distally, and therefore frees the cam bracket  530  to be rotated about pivot pin  532  and handle  482  to be rotated distally. Upon rotation of the cam bracket  530  about the pivot pin  532 , the connecting link  500  is drawn distally, and the carriage  510  moves distally. 
   As the latch mount  420  is positioned to displace the sensing link  490 , it further aligns the recess  424  with the sleeve  224 , and aligns the locking hook  514  of the locking arm  512  with the catch  422  of the latch mount  420 . 
   In much the same fashion as the first embodiment described above, when the handle  482  is rotated counter-clockwise, the link  500  will be pulled distally. As shown in  FIG. 20 , the carriage  510  will draw the locking arm  512  to the left and cause the pin  520  to drive the proximal end of the locking arm  512  downward. The locking hook  514  engages the catch  422  while drawing the foot section  450  against the patient support, fully engaging the sleeve  224  in the recess  424 . 
   As the handle  482  is rotated distally, the back plate  536  of the cam bracket  530  contacts the bottom of the side rail  456  as the handle  482  reaches a horizontal position. The arrangement is configured such that when the handle  482  is in the horizontal position, the locking mechanism  480  is fully engaged with the sleeve  224  fully seated in the recess  424  and the removable foot section  450  closely drawn against the patient support. 
   Alternate Embodiments of FIGS.  21 - 24   
   Referring now to  FIGS. 21-24 , alternative locking mechanism embodiments  1180 ,  2180 ,  3180 ,  4180  are illustrated. 
   In  FIG. 21 , a removable foot section  1150  is provided with a locking mechanism  1180 . The locking mechanism  1180  is provided on each side rail  156  and includes a main handle  1182  and a release lever  1184  projecting a short distance upwardly from each handle pivot assembly  186 . 
   In  FIG. 22 , a removable foot section  2150  is provided with a locking mechanism  2180  on each side rail  156 . The locking mechanism  2180  comprises a main handle  2182  and a release lever  2184 . The main handle  2182  includes an inwardly turned portion  2183 , and the release lever includes an inwardly turned portion  2185 , each inwardly turned portion  2183 ,  2185  extending over the upper surface  153  of the foot section pad  152 . The inwardly turned portions  2183 ,  2185  lack a continuous bight portion therebetween. 
   In  FIG. 23 , a removable foot section  3150  is provided with a locking mechanism  3180  on each side rail  156  having main handles  3182  and release levers  3184  pivotally connected in a handle pivot assembly  3186 . The release lever  3184  is positioned proximally of the main handle  3182  for grasping by an operator. The main handles  3182  and the release levers  3184  curve proximally. 
   In  FIG. 24 , a removable foot section  4150  is provided with a locking mechanism  4180  comprising a main handle  4182 . The main handle  4182  is pivotally or slidably mounted to the removable foot section between the side rails  156 , and configured to release the locking mechanism  4180 . 
   Although a particular preferred embodiment of the invention has been disclosed in detail for illustrative purposes, it will be recognized the variations or modifications of the disclosed apparatus, including the rearrangement of parts, lie within the scope of the present invention.