Abstract:
A patient support is provided for supporting a patient. Patient support includes a frame, a deck, a mattress and siderails. The deck includes a panel having apertures that receive upside down U-shaped wire loops therein to removably couple the panel to the frame. Top portions of the wire loops extend above the panel and serve as restraint strap holders.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 10/557,524, filed Nov. 8, 2006, now U.S. Pat. No. 7,644,457, which is the U.S. national phase under 35 U.S.C. §371 of PCT International Application No. PCT/US2004/016260, which has an international filing date of May 20, 2004, designating the United States of America, and which claims the benefit of U.S. Provisional Patent Application Ser. No. 60/472,260, filed May 21, 2003, the disclosures of each of which are hereby expressly incorporated by reference herein. 
    
    
     BACKGROUND AND SUMMARY OF THE INVENTION 
     The present invention relates to a hospital bed. More particularly, the present invention relates to a hospital bed having siderails, an articulating deck, and a mattress. 
     Hospital bed and other patient supports are known. Typically, such patient supports are used to provide a support surface for patients or other individuals for treatment, recuperation, or rest. Many such patient supports include a frame, a deck supported by the frame, a mattress, siderails configured to block egress of a patient from the mattress, and a controller configured to control one or more features of the bed. 
     Additional features of the present invention will become apparent to those skilled in the art upon consideration of the following detailed description of an illustrated embodiment exemplifying the best mode of carrying out the invention as presently perceived. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A detailed description particularly refers to the accompanying figures in which: 
         FIG. 1  is a perspective view of a patient support according to the present disclosure showing the patient support including a frame, a deck, a mattress supported by the deck, a head board, a foot board, a pair of head end siderails, and a pair of foot end siderail; 
         FIG. 2  is a side elevation view showing the mattress supported in a flat and horizontal position; 
         FIG. 3  is a view similar to  FIG. 2  showing a head section of the deck in a raised position and the head and foot end siderails having complementary profiles; 
         FIG. 4  is a view similar to  FIG. 3  showing the foot end siderail in a lowered position and the head and foot end siderails having complementary profiles permitting the foot end siderail to be lowered when the head section of the deck is raised; 
         FIG. 5  is a diagrammatic view showing an intermediate frame of the patient support in a horizontal position and the deck in an articulated position; 
         FIG. 6  is a view similar to  FIG. 5  showing the intermediate frame in the Trendelenburg position and the deck in a substantially flat position; 
         FIG. 7  is a perspective view of a portion of the patient support of  FIG. 1  showing portions of a caster wheel, a brake pedal in a braked position, and a brake position detection switch; 
         FIG. 8  is a view similar to  FIG. 7  showing the brake pedal in an un-braked position; 
         FIG. 9  is a perspective view of a center or fifth wheel assembly showing the fifth wheel assembly coupled to the frame of the patient support of  FIG. 1  and a wheel of the patient support facing in a direction parallel with the longitudinal axis of the patient support; 
         FIG. 10  is a view similar to  FIG. 9  showing the wheel facing in a direction that is neither parallel or perpendicular with the longitudinal axis of the patient support; 
         FIG. 11  is a view similar to  FIG. 9  showing the wheel facing in a direction that is perpendicular with the longitudinal axis of the patient support; 
         FIG. 12  is a cross-section view taken along line  12 - 12  of  FIG. 9  showing a ball bearing positioned in a first valley of a wheel position holder; 
         FIG. 13  is a cross-sectional view taken along line  13 - 13  of  FIG. 10  showing the ball bearing positioned on a first peak of the wheel position holder; 
         FIG. 14  is a cross-sectional view taken along line  14 - 14  of  FIG. 11  showing the ball bearing positioned in a second valley of the wheel position holder; 
         FIG. 15  is an exploded assembly view of the caster wheel assembly; 
         FIG. 16  is a perspective view of portions of the deck showing the deck including three removable deck panels; 
         FIG. 17  is a view similar to  FIG. 16  showing the deck panels removed from the remainder of the deck; 
         FIG. 18  is perspective view of the deck showing patient restraint straps coupled to the deck; 
         FIG. 19  is a cross-sectional view taken along lines  19 - 19  of  FIG. 2  showing one of the removable deck panels including gap fillers positioned adjacent to the head end siderails to partially fill the gap therebetween and the mattress including chamfered corners to receive the gap fillers; 
         FIG. 20  is a perspective view of a portion of the patient support of  FIG. 1  showing a head end deck panel, the head board, and one of the head end siderails having curved portions that converge to partially fill gaps defined therebetween; and 
         FIG. 21  is a top plan view showing the curved portions of the head board and the head end siderail. 
     
    
    
     DETAILED DESCRIPTION 
     A patient support  10  according to the present disclosure is shown in  FIG. 1 . Patient support  10  includes a base frame  12 , an intermediate frame  14  supported by base frame  12 , a deck  16  supported by intermediate frame  14 , a mattress  18  supported by deck  16 , a headboard  20 , a footboard  22 , a pair of head end siderails  24 , and a pair of foot end siderails  26 . Footboard  22  is positioned over an extendable foot support. Additional details of a suitable extendable foot support is provided in European Patent Publication No. EP0681799 A1, titled “Blocking device for an extension relative to a piece of furniture, and piece of furniture equipped with it,” filed May 5, 1995, to Pascal Guguin, the disclosure of which is expressly incorporated by reference herein. 
     Base frame  12  is supported on the floor by a plurality of caster wheels  28  and a centered or fifth wheel assembly  30 . Intermediate frame  14  is coupled on each end to extendable columns  31  which can be extended or retracted to position intermediate frame  14  and deck  16  in the Trendelenburg or Reverse Trendelenburg positions. Additional details of suitable extendable columns is provided in French Patent Publication No. FR2780638, titled “Hospital bed with telescoping columns,” filed Jul. 1, 1998, to Robic Dominique, the disclosure of which is expressly incorporated by reference herein. 
     Deck  16  is configured to articulate between a plurality of positions. Deck  16  includes a head section  32 , a seat section  34 , a thigh section  36 , and a foot section  38  which are pivotably coupled together. 
     Head end siderails  24  are coupled to head section  32  and may be moved between raised and lowered positions by siderail linkages  40 . Additional details of suitable siderail linkages are provided in PCT Publication No. WO 02/32271 A 1, titled “Bed with Articulated Barrier Elements,” filed Oct. 18, 2000, to Hensley et al. and U.S. Pat. No. 6,163,903, titled “Chair Bed,” filed Feb. 4, 1998, to Weismiller et al, the disclosures of which are expressly incorporated by reference herein. Foot end siderails  26  are coupled to intermediate frame  14  by siderail linkages  40  between thigh section  36  and foot section  38  and can also be moved between raised and lowered positions. 
     A control system is provided to control various functions of patient support  10 . The control system and the remainder of patient support  10  are powered by a building&#39;s power supply through an AC plug connector  44  coupled to a building outlet  46 . If AC plug connector  44  is unplugged from building outlet  46  or the building&#39;s power is lost, patient support  10  is powered by a battery (not shown) supported by base frame  12 . 
     As shown in  FIG. 2 , head section siderail  24  include handles  50 ,  52 , upper portion  54 , lower portion  56 , and notch  58 . Foot section siderail  26  includes handles  60 ,  62 , upper portion  64 , lower portion  66 , and extended portion  68 . Deck  16  can be moved into an articulated position, as shown in  FIG. 10 , by moving head section  32  in direction  70 . As shown in  FIG. 3 , upper portion  54  of head section siderail  24  complements upper portion  66  of foot section siderail  26  so that head section siderail  24  does not interfere with foot section siderail  26  when deck  16  is in the articulated position. 
     Lower portion  56  of head section siderail  24  and lower portion  66  of foot section siderail  26  are also shaped to correspond with one another so that a gap  72  defined between lower portions  56 ,  66  remains substantially constant during articulation of deck  16 . During articulation of deck  16 , a gap  74  defined between upper portions  66 ,  52  narrows significantly while gap  72  between lower portions  60 ,  58  remains substantially constant. In the articulated orientation with both siderails  24 ,  26  in the raised position, as shown in  FIG. 3 , notch  58  is positioned to receive extended portion  68  of foot section siderail  26 . 
     As shown in  FIG. 4 , when foot section siderail  26  is moved to the lowered position, the curvature of upper portion  64  of foot section siderail  26  is configured to complement the curvature of lower portion  56  of head section siderail  24 . The radius of curvature of upper portion  64  of foot section siderail  26  is configured to be substantially centered about a pivot axis  76  of head section  32 . This allows foot section siderail  26  to be moved between the raised and lowered positions when the deck is in the articulated position as shown in  FIGS. 3 and 4 . A portion of the radius of curvature of lower portion  56  of head section siderail  24  is also substantially centered about pivot axis  76 . 
     Head section  32  is pivotably and slidably coupled to a channel or rail  78  at pivot axis  76  (shown in phantom). Rail  78  is coupled to intermediate frame  14 . Rail  78  includes a slot (not shown) that allows pivot axis  76  of head section  32  to slide horizontally as head section  32  is moved between the substantially coplanar position as shown in  FIG. 2  and the articulated position as shown in  FIG. 3 . A link  80  is pivotably coupled on one end to head section  32  at a pivot axis  82  and coupled to intermediate frame  14  on the other end at a pivot axis  84 . 
     Referring now to  FIGS. 2 and 3 , as head section  32  rotates in direction  70  into the articulated position, pivot axis  76  slides in the slot in rail  78  towards foot board  22 . Additional details of rail  78  and link  80  are provided in PCT Publication No. WO 02/076266 A1, titled “Bed Equipped with a Back Elevator,” filed Mar. 26, 2002, to Gippert et al., the disclosure of which is expressly incorporated by reference herein. 
     Head section siderail  24  also includes angle indicator  88  which, in the preferred embodiment, includes a slot formed in siderail  24  and a ball bearing movable in the slot to indicate the angle of inclination of head section  32  relative to intermediate frame  14 . Head section siderail  24  also includes recessed portions  90 ,  92  along lower edge  94  of head section siderail  24 . Recessed portions  90 ,  92  allow a caregiver to comfortably stand beside patient support  10  when head section siderail  24  is in the lowered position without interfering with the care givers&#39; feet. 
     Foot section siderail  26  also includes an angle indicator  96  which, in the preferred embodiment, includes a slot formed in siderail  26  and a ball bearing movable in the slot to indicate the angle of inclination of intermediate frame  14  relative to the floor. Position indicator  96  can be used to determine the position of deck  16  relative to the floor during movement by columns  31 . Additional description of angle indicators  88 ,  96  is provided in U.S. Pat. No. 6,182,310, titled “Bed Side Rails,” filed Jan. 12, 1998, to Weismiller et al., the disclosure of which is expressly incorporated by reference herein. 
     Foot section siderail  26  also includes recessed portions  98  on a lower edge  110 . Recessed portions  98  are shaped to allow a caregiver to stand adjacent patient support  10  when siderail  26  is in the lowered position. Recessed portions  98  are shaped to eliminate or minimize contact with the caregivers&#39; feet when he or she is positioned next to patient support  10 . 
     As shown in  FIG. 1 , the control system of patient support  10  includes siderail controls  112  permanently coupled to head end siderails  24  and pendent controls  113  removably coupled to any of head and foot end siderails  24 ,  26 . Additional details of suitable siderail controls and pendant controls is provided in U.S. patent application Ser. No. 09/750,741, titled “Hospital Bed,” filed Dec. 29, 2000, to Osborne et al. and U.S. Patent Application Ser. 60/408,698, titled “Hospital Bed,” filed Sep. 6, 2002, to Menkedick et al., the disclosures of which are expressly incorporated by reference herein. 
     Siderail controls  112  are configured to actuate a shock feature of patient support  10 . Referring now to  FIGS. 5 and 6 , when the shock feature provide by siderail control  112  is activated, the control system flattens deck  16  to a substantially coplanar orientation, as shown in  FIG. 1 , and positions deck  16  in the Trendelenburg position simultaneously. If patient support  10  is in the articulated orientation, as shown in  FIG. 5 , when siderail control  112  is activated, sections  34 ,  36 ,  38  of deck  16  are lowered to the substantially coplanar orientation and extendable column  31  at the head end of patient support  10  is lowered while extendable column  31  at the foot end of patient support  10  is extended to position deck  16  in the Trendelenburg position as shown in  FIG. 6 . Siderail control  112  can be a momentary switch or any other suitable user input device. In the preferred embodiment, the control system begins flattening deck  16  and moving deck  16  into the Trendelenburg position only while the siderail control  112  is activated when a button (not shown) is depressed. 
     Referring now to  FIG. 18 , deck  16  includes a head deck panel  114 , a seat deck panel  116 , a thick deck panel  118 , and a foot deck panel  120 . Head deck panel  114  is rigidly coupled to head section  34  and seat, thigh, and foot deck panels  116 ,  118 ,  120  are removable from seat and foot sections  36 ,  38  of deck  16 . Deck panels  114 ,  116 ,  118 ,  120 , head section siderail  24 , and headboard  20  are preferably formed of blow-molded plastic so that they are hollow. According to alternative embodiments of the present disclosure, other suitable materials such as metal, wood, or composites may also be used. 
     As shown in  FIG. 20 , corner portions  122  of deck panel  114  is elevated to narrow gaps  124 ,  126  defined between head section siderail  24  and deck panel  114  and headboard  20  and deck panel  114 , respectively. Headboard  20  includes curved portions  128  and head section siderail  24  includes curved portions  130 . Curved portions  128 ,  130  are configured to narrow gap  132 , as shown in  FIG. 21 , defined between headboard  20  and head section siderail  24 . 
     Curved portions  128 ,  130  and corner portion  122  of head deck panel  114  converge together to narrow gaps  124 ,  126 ,  132 . In the preferred embodiment, hand holes  134  are provided in corner portions  122  of head deck panel  114  to permit a caregiver to grab head section deck panel  114  to move patent support  10 . In the preferred embodiment, curved portions  128 ,  130 , and corner portion  122  are provided at each corner of the longitudinal end of the head end of patient support  10 . According to alternative embodiments of the present disclosure, the converging portions are also provided on the foot end of the patient support. 
     Referring now to  FIGS. 16 and 17 , deck  16  and deck panels  116 ,  118 ,  120  are shown that support mattress  18 . Deck panel  116  is removably coupled to seat section  34  of deck  16  by restraint holders  138 . Deck panel  116  includes openings  140  which are sized to fit over restraint holders  138 . Deck panel  116  can be removed from seat section  34  of deck  16  by lifting deck panel  116  above restraint holders  138 . Deck panels  118 ,  120  also include openings  140  which receive respective restraint holders  138  in the same fashion. 
     Deck panels  116 ,  118 ,  120  also include gap fillers  142  positioned adjacent the ends of head and foot end siderails  24 ,  26 . In the preferred embodiment, gap fillers  142  are semicircular-shaped or half moon-shaped and are integral with deck panels  116 ,  118 ,  120 . Gap fillers  142  are positioned under mattress  18  when mattress  18  is positioned on deck panels  116 ,  118 ,  120 . As shown in  FIG. 2 , gap fillers  142  are designed to narrow the respective gaps  144 ,  146 ,  148  defined between deck panels  116 ,  118 ,  120  and lower edges  76 ,  72  of head and foot end siderails  24 ,  26 , respectively. Similar gap fillers are also disclosed in PCT Publication No. WO 02/076266 A1, titled “Bed Equipped with a Back Elevator,” filed Mar. 26, 2002, to Gippert et al. and French Patent Application No. FR 01 08540, titled “Lit Medicalise a Plan de Couchage Amovible,” filed Jun. 28, 2001, to Barbu et al., the disclosures of which are expressly incorporated by reference herein. 
     Referring now to  FIGS. 18 and 19 , mattress  18  includes chamfered lower corner portions  150  that extend along the length of each longitudinal side of mattress  18 . As shown in  FIG. 19 , chamfered portions  150  permits mattress  18  to be positioned on deck panels  114 ,  116 ,  118 ,  120  without interference from the gap fillers  142 . As shown in  FIG. 19 , gap filler  142  contacts chamfered portions  150  of mattress  18  to prevent mattress  18  from moving laterally when positioned on deck  16 . According to an alternative embodiment of the present disclosure, the chamfered portions are only provided at the locations of the gap fillers. 
     As shown in  FIG. 18 , restraint holders  138  extend through openings  140  in deck panels  116 ,  118 ,  120 . Restraint straps  152  are provided that are placed through restraint holders  138  and extended around mattress  18  as shown in  FIG. 1 . Restraint straps  152  are placed over a patient to secure the patient to patient support  10 . According to alternative embodiments of the present disclosure, the restraint holders do not extend completely through the openings in the respective deck panels. Additional details of suitable restraint holders and restraint straps are provided in French Patent Application No. FR 01 08540, titled “Lit Medicalise a Plan de Couchage Amovible,” filed Jun. 28, 2001, to Barbu et al., the disclosures of which are expressly incorporated by reference herein. 
     As shown in  FIG. 1 , the control system includes a battery enable switch  154 , which allows a person, such as a caregiver to operate the electrically controlled functions of patient support  10  using battery power when AC power is not available. In the illustrated embodiment, one battery enable switch  154  is located on head section siderail  24  and another battery enable switch (not shown) is located on pendent controller  113 . According to alternative embodiments of the present disclosure, the battery enable switch is located anywhere on the patient support as necessary or convenient. Battery enable switches  154  are electrically coupled to the battery system (not shown). 
     Battery enable switch  154  is a momentary switch such as a push button in the preferred embodiment, although any other suitable switch could be used. In the preferred embodiment, switch  154  includes a light emitting diode (LED) enclosed in a translucent or transparent plastic housing. The LED is “on” (i.e., illuminated) when either AC or battery power is being supplied to patient support  10 . When patient support  10  is disconnected from AC power, such as when a plug  44  is disconnected from wall socket  46 , switch  154  ceases being illuminated. 
     When AC power to patient support  10  is cutoff, a timing circuit (not shown) is initiated. In the preferred embodiment, after patient support  10  is disconnected from AC power for twenty minutes and any of the electrically controlled features of patient support  10  have not been actuated for a time period of twenty minutes, patient support  10  is placed in sleep mode. In sleep mode, minimal power is provided to patient support  10  by the battery backup system. During sleep mode, the electrical operable functions of patient support  10  are disabled. 
     In the preferred embodiment, when the patient support  10  is running on battery power provided by the battery, activation of one of the battery enable switches  154  causes patient support  10  to switch out of sleep mode and receive sufficient power from the battery so that at least certain electrically operational functions of patient support  10 , such as movement of patient support  10  into emergency Trendelenburg position, can be performed. In the illustrated embodiment, battery enable switch  154  is activated by the application of pressure on one of switches  154  with ones&#39; finger. According to an alternative embodiment, the battery enable switches are not provided and activating any one of the bed function control buttons while patient support  10  is in sleep mode will switch it out of sleep mode. 
     In the preferred embodiment, the timing circuit waits for a predetermined time period of twenty minutes so that if no operational activity occurs within the twenty minute period after the battery enable switch  154  has been activated or since the previous operational activity, patient support  10  enters sleep mode. If one of the bed function control buttons is activated within the twenty minute time period, the timing circuit is reset to zero. In this manner, battery power is conserved and a smaller battery can be used to support the battery system. 
     Battery enable switches  154  permit patient support  10  to meet regulatory requirements by enabling at least certain of the bed&#39;s operational features to be operable on battery backup power only when needed. According to alternative embodiments of the present disclosure, the timing circuit can be set to enter sleep mode after any predetermined time period, such as five minutes, one hour, etc. Details of another suitable battery enable system is provided in U.S. Patent Application Ser. 60/408,698, titled “Hospital Bed,” filed Sep. 6, 2002, to Menkedick et al., the disclosure of which is expressly incorporated by reference herein. 
     Referring now to  FIGS. 7 and 8 , patient support  10  includes a brake alarm that produces an audible and/or visual alarm signal when a brake  156  that locks caster wheel  28  is moved from the braked position, as shown in  FIG. 7 , to the unbraked position as shown in  FIG. 8  while patient support  10  is still connected to AC power through wall socket  46 . By activating the alarm, damage to plug  44  and other components of patient support  10  can be avoided. 
     Brake  156  includes a brake pedal  160  that rotates an octagonal brake shaft  158  to move brake  156  between the braked and unbraked positions. A lever  161  is coupled to brake shaft  158  so that as brake shaft  158  rotates, lever  161  also rotates. Additional details of a suitable brake is provided in French Patent Application FR02 02510, titled “Cadre de Dispositif a Usage Medical Ou Paramedical de Support Roulant d&#39;une Personne, a Roulettes Facilement Demontables, et Dispositif Ainse Equuipe”, filed Feb. 28, 2002, to Gippert et al., and corresponding PCT Application No. unknown claiming priority, to Gippert et al., which claims priority to French Patent Application FR 02 02510, the disclosures of which are expressly incorporated by disclosure herein. 
     A switch  162  is provided that is coupled to a brake alarm controller (not shown) of the control system via wires  164 . Switch  162  includes a spring  166  positioned adjacent to lever  161 . Switch  162  is coupled to frame  24  by another spring  167 . In the preferred embodiment, spring  167  is made of a resilient metallic material to permit some movement of switch  162 . 
     When brake  156  is in the braked position, as shown in  FIG. 7 , lever  161  depresses spring  166  on switch  162  to complete an electrical circuit. When brake  156  is moved to the unbraked position, as shown in  FIG. 8 , lever  161  is rotated away from spring  166 . Spring  166  is then biased away from electrical switch  162  and the electrical circuit is broken. The brake alarm controller detects that the circuit has been broken and determines that brake  156  has moved from the braked position to the unbraked position. According to alternative embodiments of the present disclosure, the braked and unbraked positions of brake  156  are reversed or the brake alarm controller is programmed to activate the brake alarm signal when the circuit is completed rather than broken. 
     When the brake alarm controller determines that brake  156  is no longer in the braked position, it determines if patient support  10  is still plugged into an AC power source such as wall socket  46 . If plug  44  of patient support  10  is plugged in to wall socket  46  and receiving AC power while brake  156  is in the unbraked position, an alarm such as an audible alarm and/or a flashing indicator light on control panel  112  will signal to warn the caregiver not to move patient support  10  until plug  44  is removed from wall socket  46 . 
     Referring now to  FIGS. 9-15 , fifth wheel assembly  30  is coupled to frame  24  of patient support  10 . Fifth wheel assembly  30  is configured to assist a caregiver in steering patient support  10  by providing a central pivot point about which to turn patient support  10 . 
     Fifth wheel assembly  30  includes a caster wheel  168  that rolls along the floor and is configured to pivot or swivel about a vertical axis  170 . Fifth wheel assembly  30  further includes a wheel position holder  172  configured to permit such swiveling. However, position holder  172  also encourages or urges caster wheel  168  to remain in predetermined orientation relative to vertical axis  170 . 
     As shown in  FIG. 9 , caster wheel  168  is positioned in a first parallel position that is parallel to a longitudinal axis  174  of patient support  10 . When in this position, caster wheel  168  is aligned to roll along the floor when patient support  10  is being pushed in direction  176  along longitudinal axis  174  of patient support  10  such as when patient support  10  is being pushed down a hallway. In  FIG. 11 , caster wheel  168  is positioned in a second perpendicular position that is perpendicular to longitudinal axis  174  of patient support  10 . When in this position, caster wheel  168  is aligned to roll along the floor when patient support  10  is being pushed in direction  178  perpendicular to longitudinal axis  174  such as when patient support is being positioned in a room. 
     Positioning fifth wheel  168  parallel to or perpendicular to longitudinal axis  174  of patient support  10  allows a caregiver to easily steer patient support  10  during movement of patient support  10  in a hallway or in a patient&#39;s room. Another suitable fifth wheel assembly is described in French Patent No. 2783463, titled “Rolling support for medical usage, has wheel held by bracket mounted on support shaft, carried in spring loaded sliding housing, which has lower edge profiled to fit on to roller cam fitted to support shaft,” filed Sep. 9, 1998, to Pascal Guguin, the disclosure of which is herein expressly incorporated by reference. 
     Position holder  172  is configured to permit movement of wheel  168  to either the first parallel position or the second perpendicular position. However, if wheel  168  is positioned between these two positions, position holder  172  urges wheel  168  back toward either the first parallel position or the second perpendicular position. Thus, if wheel  168  is in an intermediate position as shown in  FIG. 10 , position holder  172  urges wheel  168  either toward the first parallel position shown in  FIG. 9  or toward the second perpendicular position shown in  FIG. 11 . 
     Fifth wheel assembly  30  further includes a base  180  coupled to frame  24  as shown in  FIG. 9 . In the preferred embodiment, base  180  is positioned in the middle of frame  24  as shown in  FIG. 1 . According to alternative embodiments of the present disclosure, base  180  is placed elsewhere on frame  24  such as under the center of gravity of the patient support and/or patient. 
     Base  180  is saddle-shaped and includes a pair of side plates  182  and a middle plate  184  extending between side plates  182 . Side plates  182  include openings  185 ,  186 ,  188 . Position holder  172  includes a saddle-shaped base  190  coupled between side plates  182 . Base  190  includes opening  192  (one not shown) corresponding to openings  185  of side plates  182  and a bearing-receiving opening  192  as shown in  FIG. 15 . 
     Wheel assembly  30  further includes a post or stem  194  positioned to extend through an opening  196  formed in middle plate  184  of base  180 . A first upper link  198  is rigidly coupled to stem  194  and a second lower link  210  is pivotably coupled to first upper link  198  by a rod  212 . Wheel  168  is rotatably coupled to second lower link  210  by an axle  214 . 
     Wheel assembly  30  includes a pair of gas springs or biasers  216  pivotably coupled to upper link  198  by a first coupler  218  and pivotably coupled to lower link  210  by a second coupler  220 . Gas springs  216  urges wheel  168  into contact with the floor surface. Thus, if wheel  168  encounters a pump or depression on the floor, wheel  168  travels up or down and remains in contact with the floor. 
     As shown in  FIG. 15 , stem  194  includes an upper opening  222 , an annular channel  224 , and a collar  226 . Wheel assembly  30  includes an upper sleeve or bearing  228  positioned between base  190  and an upper portion  230  of stem  194  and a lower sleeve or bearing  232  positioned between collar  226  and middle plate  184  of base  180  when wheel assembly  30  is fully assembled as shown in  FIG. 12 . Bearings  228 ,  232  reduce the friction and wear between stem  194  and bases  190 ,  180 . To retain stem  194  in bases  190 ,  180 , a pin  234  is inserted through openings  185  of base  180  and corresponding openings  192  of base  190  and passes through a portion of channel  224  of stem  194  as shown in  FIGS. 9-12 . Because channel  224  is annular, stem  194  can rotate while pin  234  is positioned in channel  224 . 
     As shown in  FIG. 15 , position holder  172  includes a first cam member  236  coupled to side plates  182 , a second cam member  238  positioned to interact with first cam member  236 , and biaser or spring  237  positioned to urge second cam member  238  toward first cam member  236 . First and second cam members  236 ,  238  cooperate to urge wheel  168  to either the first parallel or second perpendicular positions. 
     First cam member  236  includes three spacers  240 , two ball bearings  242 , and a pin  244 . Pin  244  is inserted through opening  186  in side plates  182 , spacers  240 , and ball bearings  242  to support bearings  242  above second cam member  238  as shown in  FIGS. 12-14 . 
     Second cam member  238  includes an upper collar  246  having a sinusoidal cam surface  248 , a shoulder  248 , a shaft  250 , and a square keyed portion  252 . When fifth wheel assembly  30  is fully assembled, second cam member  238  is positioned in opening  222  of stem  194  and spring  237  as shown in  FIGS. 12-14 . Lower end  256  of passage  254  has a square profile that complements keyed portion  252  of second cam member  238 . Thus, when wheel  168  and stem  194  rotate, second cam member  238  also rotates. However, second cam member  238  can move up and down in passage  254 . Shoulder  248  of second cam member  238  is positioned over spring  237  so that second cam  238  is urged upwardly toward first cam member  236 . 
     In the preferred embodiment, cam surface  248  on the upper end of second cam member  238  has a smooth sinusoidal profile that includes a pair of first peaks  258 , a pair of second peaks  260 , a pair of first valleys  262 , and a pair of second valleys  264 . Each respective first peak  258 , second peak,  260 , first valley  262 , and second valley  264  is positioned opposite one another about vertical axis  170  of stem  194 . Peaks  258 ,  260  separate valleys  262 ,  264  so that valleys  262 ,  264  are spaced approximately 90° apart on cam surface  248  about axis  266 . 
     Valleys  264  are slightly deeper than valleys  262  in the preferred embodiment. According to alternative embodiments of the present disclosure, the cam surface has fewer or more valleys and peaks, peaks with sharp contours or other contours to provide other suitable profiles. 
     When fifth wheel assembly  30  is assembled, cam surface  248  is pushed upward into contact with ball bearings  242  so that ball bearings  242  “roll over” cam surface  248 . Referring now to  FIGS. 9-11 , wheel  168  can rotate 360° relative to base  180 . However, because of cam surface  248 , wheel  168  is urged toward one of four positions either parallel or perpendicular to the longitudinal axis of patient support  10 . 
     When wheel  168  is in one of the four positions, ball bears  242  are positioned in either first valleys  262  or second valleys  264  as shown in  FIGS. 12 and 14 . When wheel  168  is rotated, ball bearings  242  roll up either peaks  258  or peaks  260  and second cam member  238  is pushed down against the bias of spring  237 . When positioned on peaks  258 ,  260 , the normal force between ball bearings  242  and cam surface  248  have both axial and radial components. The radial components urge second cam member  238  toward the nearest valley  262 ,  264 . Thus, when wheel  168  is not positioned in one of the four positions, it is urged back toward the nearest of the four positions. When ball bearings  242  ride over one of peaks  258 ,  260 , they are urged toward the nearest valley  262 ,  264 . 
     Because valleys  264  are deeper than valleys  262 , the radial components of the normal forces are greater. Thus, it is easier to move from the second perpendicular position to the first parallel position and vice versa. Because cam surface  238  is smooth, the transition of wheel  168  from one position to position is also smooth. 
     To move wheel  168  from the first parallel position to the second perpendicular position, a caregiver pushes on patient support  10  in a transverse direction. This force creates torque on wheel  168  and urges ball bearings  242  to ride up one of peaks  258 ,  260 . Once wheel  168  has rotated approximately 45°, ball bearings  242  are positioned on top of peaks  258 ,  260 . With further movement of wheel  168  about axis  166 , ball bearings  242  and wheels  168  are urged toward the second perpendicular position. 
     To move wheel  168  from the second perpendicular position to the first parallel position, a caregiver pushes on patient support  10  in a longitudinal direction. This force creates torque on wheel  168  and urges ball bearings  242  to ride up one of peaks  258 ,  260 . Once wheel  168  has rotated approximately 45°, ball bearings  242  are positioned on top of peaks  258 ,  260 . With further movement of wheel  168  about axis  166 , ball bearings  242  and wheels  168  are urged toward the first parallel position. 
     Fifth wheel  168  is rotated between being parallel to the longitudinal axis of patient support  10  and perpendicular to the longitudinal axis of patient support  10  and vice versa by a caregiver gently pushing patient support  10  from either one of the head or foot end or along one of the longitudinal sides of patient support  10 . 
     Preferably, instructions for the assembly, installation, and/or use of patient support  10  are provided with patient support  10  or otherwise communicated to permit a person or machine to assemble, install and/or use patient support  10 . Such instructions may include a description of any or all portions of patient support  10  and/or any or all of the above-described assembly, installation, and use of patient support  10  or components of patient support  10 . The instructions may be provided on separate papers and/or on the packaging in which patient support  10  is sold or shipped. These instructions may also be provided over the Internet or other communication system. Furthermore, the instructions may be embodied as text, pictures, audio, video, or any other medium or method of communicating instructions known to those of ordinary skill in the art. 
     The features of the present disclosure have been described with respect to beds, but they can also be used on examination tables, stretchers, gurneys, wheel chairs, chair beds, or any other patient support devices for supporting a person during rest, treatment, or recuperation. 
     Unless otherwise stated herein, the figures are proportional. Although the present invention has been described in detail with reference to preferred embodiments, variations and modifications exist within the scope and spirit of the present invention as described and defined in the following claims.