Patent Publication Number: US-2009229049-A1

Title: Adjustable Siderail and Lock Therefor

Description:
BACKGROUND 
     The subject matter of the present application relates to siderails for a patient support apparatus, such as a bed, and more particularly to lockable, adjustable height and length siderails for a hospital bed. 
     Many patient support apparatuses, such as hospital beds, include a frame, a deck, and a support surface, such as a mattress, supported by the deck. Such beds may also include siderails. The siderails can be lowered to facilitate patient movement into and out of the bed. The siderails can also be raised to safeguard the patient. When the siderails are raised, they typically extend higher than the support surface of the bed by an amount Δh. 
     From time to time an overlay may be placed on top of the support surface, or a thicker than normal mattress may be substituted for a mattress of customary thickness. Either way, it is desirable for the siderail to be adjustable to maintain the same Δh as with a standard mattress. Moreover, it is desirable to be able to easily adjust the siderail to any desired height and to be able to easily lock the siderail in a desired position and unlock it for further adjustment. 
     SUMMARY 
     A bed includes a frame, a deck connected to the frame, a siderail supported by the frame or the deck, a siderail extension having retracted and deployed positions and a lock residing in the base. The lock is selectively engageable with and disengagable from the extension for resisting or enabling movement of the extension relative to the base. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a patient support apparatus with a frame, a deck, a patient support surface, siderails and a vertically extendable siderail extension shown in a retracted position. 
         FIG. 2  is a perspective view of the siderail of  FIG. 1  showing a siderail base and the extension in a deployed position. 
         FIG. 3  is a view similar to that of  FIG. 2  showing the siderail extension separated from the siderail base. 
         FIG. 4  is a view similar to that of  FIG. 2  with a portion of the base cut away to reveal the relationship between the siderail extension and a rotary lock for the siderail extension. 
         FIG. 5  is a perspective view of a corner of the siderail showing the rotary lock residing in a bore of the siderail base. 
         FIG. 6  is a view similar to  FIG. 5  showing the rotary lock partially exploded. 
         FIG. 7  is a view similar to  FIG. 5  showing the rotary lock nearly fully exploded. 
         FIG. 8  is a view similar to that of  FIG. 4  with a grip handle removed from the lock to reveal additional components of the lock. 
         FIGS. 8A and 8B  are side elevation views showing the rotary lock in an engaged state and a disengaged state respectively. 
         FIG. 9  is a perspective view of the assembled rotary lock. 
         FIG. 10  is a perspective view of a D-rod and an end cap of the rotary lock. 
         FIG. 11  is a perspective view of the teeth of the lock engaging a toothed siderail extension. 
         FIG. 11A  is a side elevation view showing a ratchet arrangement. 
         FIG. 12  is a side view of a siderail having a linear lock engaging a leg of a siderail extension. 
         FIG. 13  is a view similar to that of  FIG. 12  showing a notched siderail extension. 
         FIG. 14  is a view similar to that of  FIG. 13  showing a ratchet arrangement. 
         FIG. 15  is a side view of a siderail assembly having a base and a horizontally extendable extension shown in its retracted position. 
         FIG. 16  is a view similar to that of  FIG. 15  showing the extension in a deployed position. 
         FIG. 17  is a side elevation view of the horizontal extension of  FIGS. 15 and 16 . 
         FIG. 18  is a view similar to that of  FIG. 15  showing the base with the extension removed. 
         FIG. 19  is a view showing portions of the siderail base, a siderail extension, and a vertical linear lock. 
         FIG. 20  is a view similar to that of  FIG. 19  showing a siderail extension with a notched leg. 
         FIG. 21  is a view similar to that of  FIG. 20  showing a variant of the notched leg. 
         FIG. 22  is a view similar to that of  FIG. 20  but showing a ratchet arrangement. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , a patient support apparatus, such as a hospital bed  10  includes a frame  11 , a deck  12 , a headboard  14  and a footboard  15 . The deck supports a patient support surface  13  such as a mattress. The support surface includes multiple sections such as a head section, a seat section, a thigh section, and a foot section, all of which are configured to articulate and move relative to one another in a manner known to those skilled in the art. The patient support apparatus  10  also includes foot end siderails  16  and  17  and head end siderails  18  and  19 , all of which may be carried or supported by frame  11  or deck  12 . Each of the siderails  16 ,  17 ,  18 , and  19  is mounted to either the frame  11  or the deck  12  by a mounting device  20 , which is a mounting device for foot end siderail  16 . Mounting device  20  includes a mechanism for raising or lowering the foot end siderail  16  with respect to the frame  11  and deck. Similar mounting devices are also present for siderails  17 ,  18 , and  19 . Other types of mounting devices such as clocking mounting devices may also be used. 
       FIGS. 2-5  depict one variant of a siderail such as siderail  17 . Siderail  17  includes a base  22  and an extension  23 . The extension approximately defines a plane and includes a top rail  21  and extension legs  24 ,  25 ,  26 . Apertures  27 ,  28 , and  29  in the base  22  translatably receive the extension legs so that the extension  23  is extendable, i.e. adjustable between a retracted position (e.g.  FIGS. 1 ,  5 ) and one or more deployed positions, one of which is shown in  FIG. 2 . At the retracted position, the rail  21  is adjacent the base. As used herein, “adjacent” means that rail  21  is in the lowest position, (i.e. as close to the base) intended by design. The adjacent condition includes conditions in which the top rail  21  is flush with the base, is in contact with the base (e.g.  FIGS. 1 ,  5 ) and is separated from the base by a minimum prescribed distance. At a representative deployed position (e.g.  FIG. 2 ), the rail  21  is spaced further from the base  22  than it is when retracted. Movement of the extension between the retracted and deployed positions occurs substantially along the plane defined by the extension. 
     Referring additionally to  FIGS. 6-10 , siderail base  22  has a bore  33  with an axis  34 . A rotary lock  30  occupies in the bore. The lock includes a number of components serially distributed along the bore axis. These components include an end cap  80  with a blind hole  100  having a part-circular or D-shaped cross-section ( FIG. 10 ) an interior spacer  70  with a central circular hole  71 , an oblong locking cam  68  with a D-shaped hole  75  and a socket  69 . Teeth  82  extend along at least a portion of the periphery of the cam. The lock also includes an indexed spacer  66  having a socket  67 . A lug  73  extends radially from the spacer and into groove  61  in the siderail bore  34  to render the spacer non-rotatable. The lock also includes a grip handle  40 . The grip handle, like the end cap  80 , includes a blind hole, not visible in any of the illustrations, with a D-shaped cross-section. The lock also includes a coil spring  62  having a spacer end  63  and a cam end  65 . When the lock is fully assembled, socket  69  of cam  68  receives cam end  65  of the spring while socket  67  of spacer  66  receives spacer end  63  of the spring ( FIG. 8 ). Spring end  65  is referred to as a displaceable end because it moves along with socket  69  when cam  68  rotates about axis  34 . Spring end  63  is referred to as a fixed end, because it is trapped or mechanically grounded in socket  67  of spacer  66 . 
     The lock also includes a D-rod  64  having a laterally outer end  83  and a laterally inner end  84 . When the lock is fully assembled, the inner end  84  is captured in blind hole  100  of the end cap ( FIG. 10 ) while outer end  83  is captured in the similar blind hole of the grip handle. The D-rod extends through the center of the coil spring  62 , and through holes  75  and  71  in the cam and interior spacer. Because cam hole  75  mimics the cross-sectional shape and size of the D-rod, rotation of the grip handle  40  causes the cam to rotate. The D-Rod and grip handle serve as a means for rotating the cam from the locked state to an unlocked state. 
     The lock is selectively engageable with and disengageable from the extension for resisting or enabling movement of the extension relative to the base. The lock has an engaged state in which the lock is engaged with the siderail extension  23  ( FIGS. 8 ,  8 A) and a disengaged state in which the lock is disengaged from the extension ( FIG. 8B ). When the lock is engaged it secures the extension in any of multiple deployed positions. In the engaged state, the force exerted by spring  62  rotates the cam  68  so that the toothed portion of the cam contacts extension leg  24 . Friction between the cam and the extension leg resists movement of the extension leg, and therefore of the entire extension  23  relative to the base  22 . Moreover, any influence tending to urge the siderail to a lower elevation will also tend to rotate the cam clockwise (as seen in  FIGS. 8 ,  8 A), which, because of the oblong shape, causes the cam to bear even more tightly against the leg  24 . The engaged state is the default state. The disengaged state is achieved through operator intervention. Specifically, an operator grasps the handle  40  and rotates it in a direction counter to the spring force (counterclockwise as seen in FIGS.  7  and  8 - 8 B or clockwise as seen in  FIG. 11 ). Because the cam is oblong, such rotation moves the cam periphery out of contact with the extension leg so that the extension  21  can be easily raised or lowered. Because the spring force biases the lock to its engaged state, the operator continually grasps the handle  40  to exert a counterforce on the spring to keep the cam periphery out of contact with the extension leg. After the operator has satisfactorily positioned the extension  23 , the operator releases the handle  40  so that the spring can urge the cam back into contact with the extension leg  24  to prevent further movement of extension  23 . Depending on how tightly the cam bears against the extension, it may be possible for the operator to merely pull up on the extension without first having to independently disengage the lock. 
     When the extension  24  is in its retracted position, it is at a retracted elevation relative to the top surface of the mattress  13 . When the extension is at any of its deployed positions, it is at a deployed elevation relative to the top surface of the mattress  13 . The deployed elevation is greater than the retracted elevation. 
     The illustrated lock also shows the use of teeth  82  to facilitate engagement of the cam with the extension leg. Alternatively, a friction enhancing treatment such as a friction tape or a coating could be applied to the periphery of the cam. In addition, the periphery of the cam could be left in a smooth state provided the coefficient of friction between a smooth cam and the extension leg is sufficient to secure the extension in the desired position. 
     The variant of the lock and siderail extension illustrated in  FIG. 11  includes teeth  91  on extension leg  24 . Teeth  82  on the cam periphery engage the teeth  91  on the extension leg to help secure the extension leg in a desired position. Alternatively, teeth could be provided on the extension leg but not on the cam periphery. 
       FIG. 11A  shows an arrangement similar to that of  FIG. 11  but in which extension leg  24  has a number of curved teeth  86  defining notches that form a ratchet arrangement. The ratchet arrangement dispenses with the need to independently disengage the lock prior to raising the extension from its retracted position to a deployed position or from one deployed position to a higher deployed position. Instead, the caregiver simply pulls up on the siderail extension  23  to raise it to a desired location. During such upward movement the teeth push back against the cam so that the extension leg can be raised. Once the operator is satisfied that the extension has been raised to the desired position, it is necessary only for the operator to cease pulling up on the extension. The spring load on the cam will then urge the cam into tight engagement with the extension leg. To lower the siderail extension, it is necessary to first turn the rotary lock to disengage the cam teeth from the extension leg. Once the siderail extension has been lowered to the desired height, the caregiver releases the handle  40  allowing the spring to urge the cam teeth  82  back into engagement with the ratchet thereby preventing further vertical movement of the extension. 
     The above described configuration employs a spring to continuously urge the cam into contact with the extension leg. However a latch that holds the lock in the disengaged state may be used in conjunction with the spring or substituted for the spring. If a latch is used in conjunction with the spring, partial rotation of the handle would suffice to disengage the lock from the extension leg, and additional rotation of the handle in the same direction would engage the latch. Once latched, the operator may release his or her grip on the handle without the spring force urging the cam back into contact with the extension leg. 
       FIGS. 12-21  illustrate linear locks. The linear locks, like the rotary lock described above, are selectively engageable with and disengageable from the extension for resisting or enabling movement of the extension relative to the base. Referring to  FIG. 12 , lock  130  resides in siderail base  22  and comprises a pull pin having a handle  132 , a piston  131 , a plunger  136  and a spring  138 . A force exerted by spring  138  urges the plunger  136  into contact with extension leg  24  to resist movement of the leg. Plunger  136  may include a friction pad  133  or other feature to increase the coefficient of friction between the plunger and the extension leg  24 . Vertical movement of extension leg  24  is resisted until an operator pulls on the handle  132  to disengage the plunger from the extension leg. The extension can then be raised or lowered to a desired position and the handle can then be released allowing the plunger  136  to move back into contact with the extension leg, thereby resisting further movement of the extension. 
       FIG. 13  shows an arrangement similar to that of  FIG. 12  using an alternative style handle  142  and an alternative extension leg  24  featuring multiple notches  144  along its length. Lock  140  resides on siderail base  22  and comprises a pull pin having handle  142 , a piston  141 , a plunger  146  and a spring  148 . A force exerted by spring  148  urges the plunger  146  into contact with extension leg  24  to resist movement of the leg. Vertical movement of extension leg  24  is resisted until an operator pulls on the handle  142  to disengage the plunger from the teeth. The extension can then be raised or lowered to a desired position and the handle can be released allowing the plunger  146  to move back into one of the notches, thereby resisting further movement of the extension. 
       FIG. 14  shows an arrangement similar to that of  FIG. 13  but in which extension leg  24  has a number of curved notches  154  that form a ratchet arrangement. This ratchet arrangement, in contrast to the notches of  FIG. 13 , dispenses with the need to pull on handle  152  to disengage plunger  156  from the extension leg prior to raising the extension from its retracted position to a deployed position or from one deployed position to a higher deployed position. Instead, the caregiver simply pulls up on the siderail extension  23  to raise it to a desired location. To lower the siderail extension, it is necessary to first pull the handle  152  to withdraw plunger  156  from teeth  154 . Once the siderail extension has been lowered to the desired height, the caregiver releases the pull pin handle  152  allowing the spring to urge the piston  156  back into a teeth  154  of the ratchet arrangement and prevent further vertical movement of the extension. 
     The principles disclosed above in the context of a siderail with a vertically deployable extension are also applicable to a siderail with a horizontally deployable extension. Referring first to  FIGS. 15-19 , siderail  160  includes siderail base  162 , a siderail extension  163 , and extension legs  164 ,  166 . Apertures  168 ,  170  in the base  162  translatably receive siderail extension legs  164 ,  166 . Lock  200  resides on siderail base  162  and comprises a pull pin having a handle  202 , a piston  201 , a plunger  206  and a spring  208 . A force exerted by spring  208  urges the plunger  206  into contact with extension leg  24  to resist movement of the extension leg. Plunger  206  may include a friction pad to  10  or other feature to increase the coefficient of friction between the plunger and the extension leg  24 . Horizontal movement of extension leg  24  is resisted until an operator pulls on the handle  202  to disengage the plunger from the extension leg. The extension can then be translated horizontally to a desired position and the handle can then be released allowing the plunger  206  to move back into contact with the extension leg, thereby resisting further movement of the extension. 
       FIG. 20  illustrates a horizontally adjustable arrangement similar to the vertically adjustable arrangement of  FIG. 13 . Extension leg  164  has a plurality of notches  212  along its length. Lock  200  includes a pull pin whose plunger  206  extends into notches  212  to resist movement of the extension leg  164  in a horizontal direction. In operation, a caregiver pulls up on pull pin  200  to withdraw the plunger from its host teeth and enable horizontal movement of siderail extension  164  relative to the siderail base. 
       FIG. 21  shows an embodiment similar to that of  FIG. 20 . However, notches  212  are on the side of the extension leg rather than on its top and the pull pin  200  is oriented horizontally rather than vertically. 
       FIG. 22  shows a horizontally adjustable arrangement similar to that of  FIG. 20  but with a ratchet arrangement not unlike the one show in  FIG. 14 . 
     A latch that holds the linear lock in the disengaged state may be substituted for or used in conjunction with the spring or other device. If a latch is used in conjunction with the spring loaded pull pin, partial translation of the plunger would suffice to disengage the lock from the extension leg, and additional movement of the handle would engage the latch. Once latched, the operator may release his or her grip on the handle without the spring force urging the cam back into contact with the extension leg. 
     In view of the preceding descriptions, additional aspects of the extendable siderail can now be appreciated. 
     Although the illustrated variants have two or three extension legs, more or fewer extension legs could be used. Further, as shown in  FIGS. 3 ,  17  and  18 , because siderail extension  23  or  163  is removable from siderail base  22  or  162 , other types or styles of extension could be used with the same siderail base  22 . 
     Although the illustrated locks disclose the use of a spring to urge the cam or plunger into engagement with the extension leg  24 , forces resulting from the use of alternative devices, for example electromagnetic devices, could also be employed. 
     In the illustrated arrangements, the lock is situated so that it engages exactly one of the extension legs, specifically extension leg  24  or  164 . However it could also be situated to engage one of the other extension legs. Alternatively, locks could be associated with two or more of the extension legs. Such multiple locks could be interconnected so the operation of any of the locks concurrently operates the other locks. 
     It will further be appreciated by those of ordinary skill in the art that patient support apparatus  10  may include a bed or patient support apparatus suitable for use in any care facility, including homes, hospitals, medical clinics or centers, rehabilitation centers, healthcare or medical facilities, nursing homes, surgical centers, or other patient care provider facilities.