Patent Publication Number: US-6983495-B2

Title: Adjustable height bed

Description:
TECHNICAL FIELD 
     The present invention relates to an adjustable bed. In particular, the present invention relates to a bed having a bed spring or other portion that is vertically adjustable, for example, for use in home health care. 
     BACKGROUND OF THE INVENTION 
     Adjustable beds are often used in home health care. Such beds typically include a height adjustment mechanism that is operable to raise or lower the bed spring. The height adjustment mechanism may be manual or electric. A manual mechanism uses a hand crank to operate a gearbox to raise and lower the bed spring. An electric mechanism uses an electric motor that rotates a drive shaft or drive tube. The drive shaft is connected with gearboxes that face inward on the respective bed ends. When the motor is actuated, rotational force is transmitted to the bed ends to synchronously raise and lower movable portions of the bed ends that support the bed spring. One such type of adjustable bed end is shown in U.S. Pat. No. 5,134,731, the entire disclosure of which is incorporated herein by reference. 
     Since the rotational force acts in the same direction of rotation at both ends of the bed, identical head and foot bed ends are not used because their gearboxes would cause one bed end to raise and the other bed end to lower. As a result, separate head ends and foot ends are typically provided for an adjustable bed. This results in the need to manufacture and store two different kinds of bed ends, and can cause mistakes when delivering and setting up a bed in a patient&#39;s home. 
     SUMMARY OF THE INVENTION 
     The present invention relates to an adjustable bed and to various features of the bed. In various embodiments, the bed includes a universal, or interchangeable, bed end that can be used at either end of the bed and can be connected with an existing motor drive assembly. The bed end may include a manual crank that is removably attached to the bed end. The bed end may include an elevating mechanism that includes a cross-beam or similar structure for transmitting motive force between fixed and movable portions of the bed end. The bed end may also include a new slip nut for transmitting and synchronizing motive force from a lead screw. The bed may further include a reversible corner plate for allowing the bed end to be used facing in either direction. The bed end may also include a plastic cover that is washable and scratch resistant. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other features of the present invention will become apparent to one skilled in the art to which the present invention relates upon consideration the following description of the invention with reference to the accompanying drawings, in which: 
         FIG. 1  is a schematic elevational view of one embodiment of an adjustable bed in accordance with the present invention; 
         FIG. 2  is a schematic elevational view of one embodiment of a bed end that forms part of the bed of  FIG. 1 ; 
         FIG. 3  is a sectional view of one embodiment of a slip nut assembly that forms part of the bed end of  FIG. 2 ; 
         FIG. 4  is a perspective view of one embodiment of a slip nut that forms part of the slip nut assembly of  FIG. 3 ; 
         FIG. 5  is a sectional view of one embodiment of a gearbox that forms part of the bed end of  FIG. 2 ; 
         FIG. 6  is an elevational view of the gearbox of  FIG. 5 ; 
         FIG. 7  is a schematic perspective view of the bed of  FIG. 1 ; 
         FIG. 8  is a view of a prior art bed end; 
         FIG. 9  is an elevational view of one embodiment of a crank that is usable with the bed end of  FIG. 2 ; 
         FIG. 10  is a view similar to  FIG. 5  showing the crank of  FIG. 9  attached to a gearbox; 
         FIG. 11  is a sectional view of an alternative gearbox embodiment that can be part of the bed end of  FIG. 2 ; 
         FIG. 12  is a sectional view of a portion of the gearbox of  FIG. 11 ; 
         FIG. 13  is a sectional view of another alternative gearbox embodiment that can be part of the bed end of  FIG. 2 ; 
         FIGS. 14–17  are views of alternative corner plates one embodiment of that can be used with the bed end of  FIG. 2 ; 
         FIG. 18  is an elevational view of one embodiment of a plastic bed end cover in accordance with the present invention; 
         FIG. 19  is a cutaway sectional view of the bed end cover of  FIG. 18 ; 
         FIG. 20  is an exploded view of an alternative plastic bed end cover embodiment in accordance with the present invention; and 
         FIG. 21  is an exploded view of another alternative plastic bed end cover embodiment in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention relates to adjustable beds. In particular, the present invention relates to a bed having a bed spring or other portion that is vertically adjustable, for example, for use in home health care. As representative of the present invention,  FIG. 1  illustrates one embodiment of a bed  10 . The bed  10  is illustrated as being placed on a floor  12 . 
     The bed  10  includes a bed end  14  that is located at the head end of the bed. The bed  10  also includes a bed end  14   a  that is located at the foot end of the bed. The bed end  14  is referred to herein as the “head end” of the bed  10 . The bed end  14   a  is referred to herein as the “foot end” of the bed  10 . The head end  14  of the bed  10  is identical to, and interchangeable with, the foot end  14   a  of the bed, as is discussed in more detail below. 
     The head end  14  of the bed  10  ( FIG. 2 ) includes a fixed portion  20  and a movable portion  22 . The fixed portion  20  of the head end  14  is that portion of the head end  14  that stays in position on the floor  12  when the height of the bed  10  is adjusted. The movable portion  22  of the head end  14  is that portion of the head end that moves vertically relative to the floor  12  and relative to the fixed portion  20  of the head end, when the height of the bed  10  is adjusted. This movement effects vertical movement of the portions of the bed on which the patient is located, as discussed below. 
     The fixed portion  20  of the head end  14  ( FIG. 2 ) includes first and second inner legs  24  and  26  that are interconnected by a cross-beam  28 . The inner legs  24  and  26  are identical to each other in construction and so their constituent parts are numbered identically. 
     Each one of the inner legs  24  and  26  has a square, tubular cross-sectional configuration with an inner side wall  30  that faces the opposite side of the bed end  14 . Each one of the inner legs  24  and  26  has an upper end portion  32  and an opposite lower end portion  34 . The inner legs  24  and  26  extend generally perpendicular to the floor  12  when the bed  10  is assembled as shown in the drawings. 
     The cross-beam  28  has a tubular, rectangular cross-sectional configuration that extends perpendicular to the inner legs  24  and  26  and parallel to the floor  12 . The cross-beam  28  has opposite upper and lower side walls  48  and  50  and opposite inner and outer side walls. The cross-beam  28  also has first and second end walls  48  and  50  that close the ends of the cross-beam and provide a mounting structure for supporting the cross-beam. 
     The cross-beam  28  is connected between the upper end portions  32  of the inner legs  24  and  26 , respectively. Specifically, the first end wall  48  of the cross-beam  28  is fixedly secured to the upper end portion  32  of the first leg  24 , specifically, the inner side wall  30 , by fastener structure that, in the illustrated embodiment, includes a plurality of bolts  52 . In a similar manner, the second end wall  50  of the cross-beam  28  is fixedly secured to the upper end portion  32  of the second leg  26 , specifically, the inner side wall  30 , by fastener structure that, in the illustrated embodiment, includes a plurality of bolts  54 . As a result, the cross-beam  28  and the first and second inner legs  24  and  26  are fixed to each other as one unit that rests on the floor  12  and that does not move vertically when the height of the bed  10  is adjusted as described below. These three pieces together form the fixed portion  20  of the head end  14 . It should be understood that the cross-beam  28  could be configured differently, so long as it comprises structure that rigidly joins the inner legs  24  and  26  for transmitting force between the movable portions  22  of the bed end  14  and the fixed portion  20  of the bed end. 
     The movable portion  22  of the head end  14  of the bed  10  includes structural and operational parts, as well as decorative/covering parts. The decorative/covering parts are not shown in  FIGS. 1–6 , so that the structural and operational parts can be viewed. The decorative/covering parts are described below. 
     The movable portion  22  of the head end  14  includes a frame structure, or frame  60 . The frame  60  includes an upper cross bar  62 , a lower cross bar  64 , and first and second outer legs  66  and  68 . 
     The upper cross bar  62  has a tubular cross-sectional configuration that extends perpendicular to the outer legs  66  and  68  and parallel to the floor  12 . The upper cross bar  62  has first and second end portions  70  and  72 . The lower cross bar  64  has a tubular cross-sectional configuration that extends perpendicular to the outer legs  66  and  68  and parallel to the floor  12 . The lower cross bar  64  has first and second end portions  74  and  76 . 
     The first and second outer legs  66  and  68  of the frame  60  are identical to each other and so their constituent parts are numbered identically. Each one of the outer legs  66  and  68  has a square, tubular cross-sectional configuration with an inner major side wall  78  that faces the opposite side (left to right as viewed in  FIG. 2 ) of the bed end  14 . Each one of the outer legs  66  and  68  has an upper end portion  80  and an opposite lower end portion  82 . The outer legs  66  and  68  extend perpendicular to the floor  12  when the bed  10  is assembled as shown in the drawings. 
     The first and second end portions  70  and  72  of the upper cross bar  62  are fixed to the upper end portions  80  of the first and second outer legs  66  and  68 , respectively, by welding, for example. The first and second end portions  74  and  76  of the lower cross bar  64  are fixed to the first and second outer legs  66  and  68 , respectively, by welding, for example. As a result, the upper and lower cross bars  62  and  64 , and the first and second outer legs  66  and  68 , are fixed to each other as one unit that is movable vertically when the height of the bed  10  is adjusted as described below. 
     The first and second inner legs  24  and  26  of the head end  14  of the bed  10  are telescopically received in the first and second outer legs  66  and  68  of the head end, respectively. The inner legs  24  and  26  are smaller in cross-sectional configuration than the outer legs  66  and  68  and are slidable within the outer legs. When the inner legs  24  and  26  are thus assembled with the outer legs  66  and  68 , the lower end portions  34  of the inner legs project from the outer legs. Casters or other floor-engaging structure  86  ( FIG. 1 ) may be fixed to the lower end portions  34  of the inner legs  24  and  26 . 
     The inner side wall  78  of the first outer leg  66  is cut away or relieved in a known manner to allow travel clearance for the bolts  52  when the first inner leg  24  moves vertically relative to the first outer leg. In a similar manner, the inner side wall  78  of the second outer leg  68  is cut away or relieved in a known manner to allow travel clearance for the bolts  54  when the second inner leg  26  moves vertically relative to the second outer leg. As a result, the entire movable portion  22  of the head end  14 , including the upper and lower cross bars  62  and  64  and the first and second outer legs  66  and  68 , is movable vertically as one unit, relative to the fixed portion  20  of the head end, when the height of the bed  10  is adjusted as described below. 
     The movable portion of the head end  14  of the bed  10  includes a drive assembly  90  for receiving rotational force and, in response, moving the movable portion  22  of the head end vertically relative to the fixed portion  20  of the head end. The drive assembly  90  includes a gearbox  140 , described below in detail, that is fixed in position on the lower cross bar  64  of the frame  60 . 
     The drive assembly  90  also includes an externally threaded acme screw or lead screw  92 . The lead screw  92  is mounted generally vertically in the frame  60 . An upper end portion  94  of the lead screw  92  is supported on the upper cross bar  62  for rotational movement relative to the frame  60  about a drive axis  96 . An upper screw pin  98  ( FIG. 3 ) projects radially outward from the lead screw  92  near the upper end portion  94  of the lead screw. The upper end portion  94  of the lead screw  92  is not movable axially relative to the upper cross bar  62 . 
     A lower end portion  100  of the lead screw  92  ( FIG. 5 ) is supported on the gearbox  140  in a manner described below for rotation relative to the frame  60 . The lower end portion  100  of the lead screw  92  includes an axially projecting tenon  102  that forms the lower terminal end of the lead screw. The lower end portion  100  of the lead screw  92  is not movable axially relative to the lower cross bar  64 . As a result, the lead screw  92  is fixed for movement vertically with the frame  60  and with the other parts of the movable portion  22  of the head end  14 . 
     The drive assembly  90  of the head end  10  also includes a slip nut assembly  104  ( FIGS. 3 and 4 ) for transmitting force between the lead screw  92  and the cross-beam  28 . The slip nut assembly  104  includes a slip nut housing  106 . The nut housing  106  is fixed by bolts  108  to the upper side wall  40  of the cross-beam  28 , at a location inside the cross-beam. As a result, the slip nut housing  104  is rigidly coupled by the cross-beam  28  to the inner legs  24  and  26 . 
     The slip nut assembly  104  also includes a slip nut. The slip nut may be of the one-piece type shown in U.S. Pat. No. 5,134,731, entitled Adjustable Bed Having Adjustable Height Legs With Synchronization Feature, the entire subject matter of which is hereby incorporated by reference. 
     Alternatively, and as preferred, the slip nut assembly  104  includes a slip nut  110  as shown and described herein. The slip nut  110  is formed as two separate pieces  112  and  114 , as seen in  FIGS. 3 and 4 . The first and second slip nut halves  112  and  114  are formed by casting or molding. The first and second slip nut halves  112  and  114  are identical to each other. 
     An upper slip nut pin  116  is formed as one piece with the first slip nut half  112 . A lower slip nut pin  118  is formed as one piece with the second slip nut half  114 . The upper and lower slip nut pins  116  and  118  project axially from opposite upper and lower end surfaces of the slip nut  110 . The two slip nut halves  112  and  114  when placed together as shown in  FIG. 3  define an internal thread convolution  120  into which the lead screw  92  is threaded. A plurality of circumferential grooves  122  are formed on the outer surface of the slip nut  110 . The grooves  122  do not extend helically but rather extend perpendicular to the drive axis  96 . 
     The slip nut assembly  104  further includes a pair of pressure plates  124  mounted in the slip nut housing  106 . The pressure plates  124  have internal grooves  126  that mesh with the external grooves  122  on the slip nut  110  to provide for relative rotation, without relative axial movement, between the slip nut and the pressure plates. The pressure plates  124  are movable laterally in the slip nut housing  106  (left to right as viewed in  FIG. 3 ) but are blocked from rotation within the housing about the axis  96 . 
     A pair of springs  128  are associated with the pressure plates  124 . Each spring  128  is biased against its associated pressure plate  124  by a respective set screw  130  that is screwed into the slip nut housing  106 . The springs  128  urge the pressure plates radially inward against the slip nut halves  112  and  114 , which are, thereby, urged radially inward against the lead screw  92 . 
     The gearbox  140  ( FIGS. 2 ,  5  and  6 ) is fixed to the frame  60  and is operable to receive rotational force from outside the head end  14  of the bed  10  and, in response, effect rotation of the lead screw  92  about the drive axis  96 . The gearbox  140  includes a housing  142 . The gearbox housing  142  has a main body portion  144  and an output portion  146  that projects upward from the main body portion. The gearbox  140  is oriented relative to the frame  60  so that the drive axis  96  extends vertically into the output portion  146  of the housing  142 . The gearbox  140  is fixed by one or more bolts  148  ( FIG. 2 ), or other means, to the lower cross bar  64  of the frame  60  of the head end  14  of the bed  10 . 
     Two bushings  150  and  152  ( FIG. 5 ) in the main body portion  144  of the housing  142  support a lower input shaft  160  for rotation relative to the housing. The bushing  152  is supported on a vertically extending internal wall  154  of the housing  142 . The wall  154  is, for clarity, not shown in  FIG. 6 . 
     The lower input shaft  160  is rotatable about an axis  162  that is perpendicular to the drive axis  96 . A lower gear assembly  164  is fixed on the lower input shaft  160  for rotation with the lower input shaft, at a location between the two bushings  150  and  152 . The lower gear assembly  164  includes a spur gear  166  and a bevel gear  168 . 
     The lower input shaft  160  has first and second opposite end portions  170  and  172 . A pair of lower drive pins  174  project radially from the lower input shaft  160  at diametrically opposite locations on the first end portion  170 . The lower drive pins  174  are fixed for rotation with the lower input shaft  160 . A pair of second drive pins  176  project radially from the second end portion  172  of the lower input shaft  160 . The second drive pins  176  are fixed for rotation with the lower input shaft  160 . 
     Two bushings  180  and  182  in the main body portion  144  of the housing  142  support an upper input shaft  190  for rotation relative to the housing. The bushing  180 , which is located above the bushing  152  of the lower input shaft  160 , is supported on the internal wall  154 . The upper input shaft  190  is rotatable about an axis  192  that is perpendicular to the drive axis  96  at a location above and parallel to the lower input shaft  160  and its axis  162 . As a result, the upper input shaft  190  is located between the lower input shaft  160  and the output portion  146  of the gearbox housing  142 . 
     An upper gear assembly  194  is fixed on the upper input shaft  190  for rotation with the upper input shaft, at a location between the two bushings  180  and  182 . The upper gear assembly  194  includes a spur gear  196  and a bevel gear  198 . The upper input shaft  190  has first and second opposite end portions  200  and  202 . A pair of upper drive pins  204  project radially from the upper input shaft  190  at diametrically opposite locations on the first end portion  200 . The upper drive pins  204  are fixed for rotation with the upper input shaft  190 . 
     The upper gear assembly  194  on the upper input shaft  190  is in meshing engagement with the lower gear assembly  164  on the lower input shaft  160 . Specifically, the spur gear  196  on the upper gear assembly  194  is in meshing engagement with the spur gear  166  of the lower gear assembly  164 . As a result, rotation of the lower input shaft  160  in either direction about its axis  162  results in rotation of the upper input shaft  190  in the opposite direction of rotation about its own axis  192 . Similarly, rotation of the upper input shaft  190  in either direction about its axis  192  results in rotation of the lower input shaft  160  in the opposite direction of rotation about its own axis  162 . 
     The output portion  146  of the housing  142  supports an output gear assembly  208 . The output gear assembly  208  includes an output bevel gear  210  that is in meshing engagement with the bevel gear  198  on the upper input shaft  190 . The output bevel gear  210  is supported in the output portion  146  of the housing  142 , by one or more bushings  212 , for rotation about the drive axis  96 . An upwardly opening mortise  214  is formed in the output bevel gear  210 . The tenon  102  on the lower end portion  100  of the lead screw  92  extends into the mortise  214  in the output bevel gear  210 . As a result, the output bevel gear  210  is fixed for rotation with the lead screw  92  about the drive axis  96 . Therefore, rotation of either the lower input shaft  160  or the upper input shaft  190  results in rotation of the lead screw  92  about the drive axis  96 . 
     The gearbox housing  142  has several access ports for the input shafts  160  and  190 . The main body portion  144  of the gearbox housing  142  has a main access opening  220  adjacent the first end portions  200  and  170  of the upper and lower input shafts  190  and  160 , respectively. The main access opening  220  faces the foot end  14   a  of the bed  10  when the bed is assembled, as shown in  FIG. 1 . A movable door or cover  222  is pivotally connected to the gearbox housing  142 . The door  222  is movable between a first position as shown in solid lines in  FIG. 5  and a second position as shown partially in dash-dot lines in  FIG. 5 . In the first position, the door  222  covers the lower input shaft  160  and makes the upper input shaft  190  accessible from the exterior of the gearbox  140 . In the second position, the door  222  covers the upper input shaft  190  and makes the lower input shaft  160  accessible from the exterior of the gearbox  140 . 
     The main body portion  144  of the gearbox housing  142  has a secondary access opening  224  adjacent the second end portion  172  of the lower input shaft  160 . The secondary access opening  224  faces away from the foot end  14   a  of the bed  10  when the bed is assembled. A movable door or cover  226  is pivotally connected to the gearbox housing  142 . The door  226  is movable between a first or closed position as shown in solid lines in  FIG. 5  in which the door covers the second end portion  172  of the lower input shaft  160 , and a second or open position (not shown) in which the door is opened and the lower input shaft  160  is accessible from the exterior of the gearbox  140 . 
     The foot end  14   a  of the bed  10  ( FIG. 1 ) is identical in construction to the head end  14 . Corresponding parts of the foot end  14   a  are identified herein with reference numerals identical to those of the corresponding parts of the head end  14 , but having the suffix “a” attached. 
     The foot end  14   a  of the bed  10  is interchangeable with the head end  14 . When the bed  10  is assembled as in  FIG. 1 , the main access opening  220   a  of the gearbox  140   a  of the foot end  14   a  of the bed faces toward the main access opening  220  of the gearbox  140  of the head end  14  of the bed. 
     Because the head end  14  and the foot end  14   a  are identical, the main access opening  220   a  of the foot end gearbox  140   a  is at the same height off the floor  12  as the main access opening  220  of the head end gearbox  140 . The lower input shaft  160   a  of the foot end gearbox  140   a  is at the same height off the floor  12  as the lower input shaft  160  of the head end gearbox  140 . The upper input shaft  190   a  of the foot end gearbox  140   a  is at the same height off the floor  12  as the upper input shaft  190  of the head end gearbox  140 . 
     The bed  10  includes a spring assembly  230  for supporting a mattress (not shown) on which the patient lies. The spring assembly shown includes a head spring  232 , a foot spring  234 , and a knee unit  236 ; other spring assemblies can be used. The several parts of the spring assembly  230  may be pivotable relative to each other and relative to the head end  14  and the foot end  14   a , in a known manner. The spring assembly  230  is supported by brackets on the movable portions  22  and  22   a  of the head end  14  and the foot end  14   a , respectively, in a known manner, for vertical movement with the movable portions of the head end and the foot end. 
     The foot spring  234  supports an electric motor shown schematically at  240  ( FIG. 1 ). The electric motor  240  is actuatable in a known manner by one or more controls, such as a pendant (not shown), to raise or lower the spring assembly  230  in a manner described below. 
     The bed  10  includes a drive tube assembly  250  for transmitting rotary force from the electric motor  240  to the head end  14  of the bed, and from the electric motor  240  to the foot end  14   a  of the bed. The drive tube assembly  250  includes a first drive tube section  252 . The first drive tube section  252  extends between and interconnects the motor  240  and the head end  14  of the bed  10 . The drive tube assembly  250  also includes a second drive tube section  254 . The second drive tube section  254  extends between and interconnects the motor  240  and the foot end  14   a  of the bed  10 . 
     The first drive tube section  252  is connected with the motor  240  in a known manner so that the first drive tube section is rotatable in a first direction of rotation, relative to both the head end  14  of the bed and the foot end  14   a  of the bed, upon “raising” actuation of the motor. The first drive tube section  252  is rotatable in a second direction of rotation opposite the first direction, upon “lowering” actuation of the motor  240 . 
     The second drive tube section  254  is connected with the motor  240  in a known manner so that the second drive tube section is rotatable in the same first direction of rotation upon “raising” actuation of the motor, and rotatable in the same second direction of rotation opposite the first direction, upon “lowering” actuation of the motor. Thus, the first drive tube section  252  and the second drive tube section  254  are coupled for rotation with each other in the same direction of rotation, relative to the head end  14  and the foot end  14   a  of the bed  10 , upon actuation of the electric motor  240 . 
     A typical position for the parts of the bed  10  is shown schematically in  FIG. 1 . The first drive tube section  252  extends from the electric motor  240  to the upper input shaft  190  of the gearbox  140  on the head end  14  of the bed  10 , as shown in dash-dot lines in  FIG. 5 . The drive pins  204  on the upper input shaft  190  of the gearbox  140  of the head end  14  couple the upper input shaft for rotation with the first drive tube section  252 . 
     The second drive tube section  254  extends from the electric motor  240  to the lower input shaft  160   a  (not shown) of the gearbox  140   a  on the foot end  14   a  of the bed  10 . The drive pins  174   a  (not shown) on the upper input shaft  160   a  of the gearbox  140   a  of the foot end  14   a  couple the lower input shaft  160   a  for rotation with the second drive tube section  254 . 
     As a result, the connection between the drive tube assembly  250  and the head end  14  of the bed  10  is at a different vertical height off the floor  12  than the connection between the drive tube assembly and the foot end  14   a  of the bed, even though the two gearboxes  140  and  140   a  are each, as a whole, at the same vertical height off the floor. 
     Upon actuation of the motor  240  in a direction of rotation so as to raise the bed  10 , the drive tube assembly  250  rotates in a first direction of rotation relative to the head end  14  and the foot end  14   a  of the bed. The first drive tube section  252  and the second drive tube section  254  both rotate in the first direction of rotation. The first direction of rotation is generally perpendicular to the axes of rotation  96  and  96   a  of the lead screws  92  and  92   a , respectively. 
     The first drive tube section  252 , which is coupled for rotation with the upper input shaft  190  of the gearbox  140  of the head end  14 , causes the upper input shaft to rotate in the first direction of rotation, for example, clockwise as viewed in  FIG. 6  as indicated by the arrow  253 . The rotation of the upper input shaft  190  is transmitted through the upper bevel gear  198  ( FIG. 5 ) into the output shaft  208  and thence into the lead screw  92  of the head end  14  of the bed  10 . 
     The lead screw  92  rotates about the drive axis  96 . The rotation of the lead screw  92  constitutes rotation relative to the slip nut  110 . Because the lead screw  92  and the slip nut  110  are threadedly engaged, this relative rotation produces relative axial movement between the lead screw and the slip nut. 
     The relative axial movement between the lead screw  92  and the slip nut  110  is produced because the slip nut does not rotate on the lead screw. The slip nut  110  does not rotate because of the pressure plates  124  of the nut assembly  104 . Specifically, the pressure plates  124  are mounted non-rotatably about the axis  96  in the nut housing  106 . The radially inwardly directed force exerted by the pressure plate springs  128 , urging the pressure plates  124  against the slip nut halves  112  and  114 , is normally strong enough so that the abutting engagement of the pressure plates and the slip nut halves couples the slip nut to the pressure plates and thus prevents the slip nut from rotating on the lead screw  92 . When the lead screw  92  is driven to rotate about its axis  96 , therefore, the rotational force transmitted from the lead screw to the slip nut is not great enough to overcome this holding force exerted by the pressure plates  124  on the slip nut, and the slip nut does not rotate with the lead screw. Instead, the slip nut  110  translates along the screw  92  (or vice versa), producing relative axial movement between the nut housing  106  and the screw. 
     The relative axial movement that results is movement of the lead screw  92  and not the nut  110 , for the following reasons. The slip nut  110  is mounted in the nut housing  106 , which is fixed to the cross-beam  28  of the fixed portion  20  of the head end  14  of the bed  10 . The fixed portion  20  of the bed  10  rests on the floor  12 , supporting the movable portion  22  of the head end  14  off the floor. As a result, force tending to produce relative axial movement between the slip nut housing  104  and the lead screw  92  tends to cause the movable portion  22  of the head end  14 , including the lead screw  92 , to move axially in space relative to the floor  12  as it rotates about the drive axis. 
     Because the lead screw  92  is fixed in position vertically on the frame  60 , the vertical movement of the lead screw  92  drives the entire movable portion  22  of the head end  14  vertically upward, relative to the fixed portion  20  of the head end. The frame  60  of the head end  14 , and the gearbox  140 , move vertically with the lead screw  96  relative to the floor  12 . 
     The structure of the fixed portion  20  of the head end  14  is advantageous as follows. Axially directed force from the slip nut housing  106  is transmitted directly into the rigid cross-beam  28 , to which the slip nut housing is fixed. This force is transmitted directly into the inner legs  24  and  26 , to which the cross-beam  28  is rigidly fixed. As a result, no cables or pulleys, such as those shown in the aforementioned U.S. Pat. No. 5,134,731, are needed in the head end  14  of the bed  10 . 
     The slip nut assembly  104  is operative to limit upward and downward travel of the movable portion  22  of the head end  14  of the bed  10 , in a manner similar to that described in U.S. Pat. No. 5,134,731 discussed above. Specifically, when the lead screw  92  reaches its end of downward travel relative to the slip nut  110 , the radially extending pin  98  ( FIG. 3 ) on the rotating screw contacts the axially projecting pin  116  on the slip nut  110 . This engagement couples the slip nut  110  for rotation with the lead screw  92 , overcoming the holding force of pressure plates  124 . As the slip nut  110  rotates thereafter, it rotates within the pressure plates  124  and thus within the slip nut housing  104 . Because the slip nut  110  is rotating with the lead screw  92 , it is no longer translating along the lead screw, and the slip nut no longer transmits axial force from the lead screw to the nut housing  106 . This eliminates further relative vertical movement between the lead screw  92  and the slip nut  110 , and the movable portion  22  of the head end  14  ceases vertical movement relative to the fixed portion  20  of the head end. 
     The above-described construction of the slip nut  100  is advantageous as follows. Because the slip nut  100  can be cast or molded, no costly machining process is needed. In addition, the axially projecting pins  116  and  118  can be formed as one piece with the remainder of the slip nut  110 , simplifying the manufacturing process. Because the two slip nut halves  112  and  114  are identical, only one mold is needed. Also, when the slip nut  110  rotates at its end of travel as described above, the parting line between the two slip nut halves  112  and  114  makes an audible clicking noise that can signal the user of the bed of the end of travel condition. 
     At the same time that the first drive tube section  252  is driving the lead screw  92  of the head end  14  to move the head end upward, the second drive tube section  254  is driving the lead screw  92   a  of the foot end  14   a  of the bed  10  to move the foot end upward.  FIG. 7  is a schematic perspective view of parts of the bed  10  that illustrates the directions of movement of the parts. The second drive tube section  254  is coupled (not shown) to the lower input shaft  160   a  of the gearbox  140   a  of the foot end  14   a . Upon actuation of the motor  240  to raise the head end  14  of the bed  10  as described above, the second drive tube section  254  rotates in the same first direction of rotation in space relative to the head end  14  and the foot end  14   a  of the bed. 
     The rotation of the second drive tube section  254  causes the lower input shaft  160   a  of the foot end  14  to rotate in the first direction of rotation, which is counter-clockwise if looking at the great box  140   a  as viewed in  FIG. 6  because the foot end  14   a  faces the opposite direction from the head end  14 . This rotation of the lower input shaft  160   a  is transmitted through the bevel gears  164   a  and  194   a  into the upper input shaft  190   a , causing the upper input shaft  190   a  to rotate in the opposite direction, that is, a clockwise direction as viewed in  FIG. 6 . This rotation of the upper input shaft  190   a  is transmitted into the output shaft  208   a  and thence into the lead screw  92   a  of the foot end  14   a  of the bed  10 . 
     The lead screw  92   a  of the foot end  14   a  of the bed  10  rotates about its drive axis  96   a  within the foot end of the bed. This screw rotation within the foot end  14   a  is in the same direction in space as the direction of rotation of the lead screw  92  within the head end  14  of the bed  10 . As a result, the rotation of the lead screw  92   a  of the foot end  14   a  causes the movable portion  22   a  of the foot end of the bed  10  to move vertically relative to the floor  12  in the same direction as the head end  14  is moving. 
     Thus, both ends  14  and  14   a  of the bed  10  move vertically in the same direction—upward or downward as viewed in FIGS.  6  and  7 —because the drive tube assembly  250  is connected with different input points in the two gearboxes  140  and  140   a . This simultaneous movement occurs even though the first drive tube section  252  and the second drive tube section  254  are rotating in the same direction relative to the other parts of the assembled bed  10 . This result is achieved in the bed  10  by coupling the second drive tube section  254  with the lower input shaft  160   a  of the gearbox  140   a  of the foot end  14   a  whenever the first drive tube section  252  is coupled with the upper input shaft  190  of the gearbox  140  of the head end  14  of the bed  10  (or vice versa). 
     When the movable portion  22  of the head end  14  of the bed  10  and the movable portion  22   a  of the foot end  14   a  of the bed move vertically, the bed spring assembly  230  moves vertically also, relative to the floor  12 , as desired. This has the effect of raising or lowering a patient who is lying on the bed spring assembly  230 . 
     It can thus be seen that, in the bed  10  illustrated in  FIGS. 1–7 , the bed end  14  is interchangeable with the bed end  14   a , thus making the bed ends “universal”. As a result, when parts of a bed  10  are selected from a warehouse for delivery to a home customer, any two bed ends  14  can be selected; there is no need to pick a “head end” and a distinct “foot end”. This can eliminate trips back to the warehouse if an incorrect selection is made and discovered at the time of setting up the bed  10  in the home. In addition, this “universal” quality of the bed end  14  can make it unnecessary to manufacture two different bed ends for use in the bed  10 . 
     The bed end  10  described above incorporates an elevating mechanism including the cross-beam  28  that is rigidly tied between the inner legs  24  and  26 . The cross-beam  28  receives force from the lead screw  92  via the slip nut  110  and the slip nut housing  104 , and transmits that force to the inner legs  24  and  26 . It should be understood that other types of elevating mechanisms could be used. For example,  FIG. 8  illustrates a prior art bed end shown in U.S. Pat. No. 5,134,731. The bed end shown in  FIG. 8  includes an elevating mechanism that uses pulleys and cables to transmit force between the slip nut housing and the inner legs of the bed end. This is one type of alternative elevating mechanism that is usable in a universal bed end  14  as described above. 
       FIGS. 9 and 10  illustrate a gearbox hi/lo crank  260  for use in the head end  14  of the bed  10 . Prior art home articulating bed designs that are semi electric beds (manual hi/lo) have a die cast primary crank with a folding handle. The crank is permanently fixed to the gearbox. Because the crank has to be located at the foot end of the bed (projecting out into the room from the outer major side surface of the foot end), then by default the bed end that has the crank must be used as the foot end; the head end and the foot end are not interchangeable. 
     Some beds also include an emergency crank that is a simple wire-form crank for emergency use only. This has one end adapted to engage the articulation motors and the other end adapted to engage the hi/lo gearbox. By virtue of its light weight construction this crank is not suitable for extended use. 
     The crank  260  ( FIGS. 9 and 10 ) of the present invention includes a two-part handle  262  that is hinged at  264  to reduce its size when installed. A slotted tube  266  projects from the handle  262 . The tube  266  has a cylindrical configuration adapted to fit over the second end portion  172  of the lower input shaft  160  of the gearbox  140  when the door  276  is pivoted upward, as shown in  FIG. 10 . A pair of diametrically opposed slots  268  in the tube  266  fit over the drive pins  176  on the second end portion  172  of the lower input shaft  160 . The tube  266  is made from steel and is strong enough together with the other parts of the crank  260  to raise or lower the bed  10  repeatedly over the lifetime of the bed end  14  without deformation. 
     The crank  260  also includes a detent member  270 . In the illustrated embodiment, the detent member  270  is a U-shaped wire spring having a base portion  272  crimped onto the tube  266 . Two resilient leg portions  274  of the wire spring  270  project from the base portion  272 . Each one of the leg portions  274  has a bent end portion  276  adapted to engage (fit behind) one of the drive pins  176  on the lower input shaft  160 . 
     To assemble the crank  260  to the gearbox  140 , the user places the tube  266  of the crank over the second end portion  172  of the lower input shaft  160 . The slots  268  in the tube  266  are fitted over the drive pins  176 . As the tube  266  is slid axially over the input shaft  160 , the bent end portions  276  of the legs  274  of the wire spring  270  engage the drive pins  176  and are cammed away from the drive pins to allow the tube to slide fully onto the input shaft. 
     When the drive pins  176  reach the ends of the slots  268 , the wire spring legs  274  resiliently move back into their starting position. In this position, the drive pins  176  engage the bent end portions  276  of the wire spring legs  274 . This engagement resists removal of the tube  266  from the input shaft  160 , without a strong pull. Thus, the crank  260  is fixedly but not permanently attached to the gearbox  140  and may be used with the gearbox for so long as the bed  10  is assembled in that location. When the bed  10  is to be disassembled, the crank  260  can be removed by the dealer. 
     The crank  260  is strong enough to be used as an everyday crank for hi/lo purposes, or for emergency (power failure) operations. Nevertheless, the crank  260  is removable from the input shaft  160  by the dealer so that it can be placed on either bed end  14  or  14   a  during assembly of the bed  10 . Because the crank  260  is removable from the bed end  14  and usable on another bed end  14 , this helps to make the bed ends  14  and  14   a  universal—that is, interchangeable at either end of the bed  10 , in comparison to a bed end having a permanently affixed crank. 
       FIGS. 11 and 12  illustrate an alternative gearbox  140   a  for use in the head end  14  or foot end  14   a  of the bed  10 . The gearbox  140   a  is similar to the gearbox  140  ( FIGS. 1–6 ), and parts that are the same or similar are given the same reference numerals with the suffix “a” added. 
     The gearbox  140   a  includes a housing  142   a . The housing  142   a  has a main body portion  144   a  and an outlet portion  146   a  that projects upward from the main body portion. The gearbox  140   a  is mounted on the frame, in a manner not shown, so that the drive axis  96   a  extends vertically into the outlet portion  146   a  of the housing  142   a.    
     Two bushings  150   a  and  152   a  in the main body portion  144   a  of the housing  142   a  support a single input shaft  280  for rotation relative to the housing. The input shaft  280  is rotatable about an axis  282  that is perpendicular to the drive axis  96   a.    
     The input shaft  280  has first and second opposite end portions  284  and  286 . A first gear assembly  288  is fixed on the input shaft  280  for rotation with the input shaft, adjacent the first end portion  284  of the input shaft. A second gear assembly  290  is fixed on the input shaft  280  for rotation with the input shaft, adjacent the second end portion  286  of the input shaft. The second gear assembly  290  is spaced apart from the first gear assembly  288 . 
     A pair of drive pins  292  project radially from the input shaft  280  at diametrically opposite locations on the first end portion  284 . The drive pins  292  are fixed for rotation with the input shaft  280 . The gearbox housing  142   a  has a single access opening  294  adjacent the first end portion  284  of the input shaft  280 . The access opening  294  is not covered by a door. 
     The output portion  144   a  of the housing  140   a  supports an output bevel gear  210   a  that is located between the first and second gear assemblies  288  and  290  on the input shaft  280 . The output bevel gear  210   a  is supported in the output portion  144   a  of the housing  140   a , by one or more bushings  212   a , for rotation about the drive axis  96   a . The output bevel gear  210   a  has a mortise and tenon connection  296  to the lead screw  92   a , as described above with reference to  FIG. 5 . As a result, the lead screw  92   a  is fixed for rotation with the output bevel gear  210   a  about the drive axis  96   a.    
     The input shaft  280  is supported by the bushings  150   a  and  152   a , for sliding movement relative to the housing  142   a  in a direction parallel to the axis of rotation  282  of the drive shaft. The input shaft  280  includes a locator pin  300  ( FIGS. 11 and 12 ) that projects radially from a location between the first and second gear assemblies  288  and  290 . The locator pin  300  is received in a U-shaped slot  302  in the housing. The slot  302  has first and second end portions  304  and  306  and a central portion  308 . 
     When the locator pin  300  is in the first end portion  304  of the slot  302 , as shown in  FIGS. 11 and 12 , the first gear assembly  288  on the input shaft  280  is in meshing engagement with the output bevel gear  210   a . As a result, rotation of the input shaft  280  in a first direction about the axis  282  results in rotation of the output bevel gear  210   a , and the lead screw  92   a , in a first direction of rotation about the drive axis  96   a.    
     When the locator pin  300  is in the second end portion  306  of the slot  302 , the input shaft  280  is moved axially from the position shown in  FIG. 11 , and the second gear assembly  290  on the input shaft is in meshing engagement with the output bevel gear  210   a . Therefore, rotation of the input shaft  280  in the first direction about the axis  282  results in rotation of the output bevel gear  210   a , and the lead screw  92   a , in a second or opposite direction of rotation about the drive axis  96   a.    
     As a result, the bed end  14  to which the gearbox  140   a  is attached can be used at either end of the bed  10 , and still provides simultaneous upward or downward movement of both bed ends, simply by moving the input shaft  280  from one position to the other. Therefore, a bed  10 , having two identical bed ends  14  with gearboxes  140   a  of the type shown in  FIGS. 11 and 12 , can use the two bed ends interchangeably simply by adjusting the gearbox as described above. 
       FIG. 13  illustrates another alternative gearbox  140   b  for use in the head end or foot end of the bed  10 . The gearbox  140   b  is similar in construction and operation to the gearbox  140   a  ( FIGS. 11 and 12 ). Parts of the gearbox  140   b  that are the same as or similar to corresponding parts of the gearbox  140   a  are given the same reference numerals with the suffix “b” attached. 
     The gearbox  140   b  ( FIG. 13 ) includes an input shaft  280   b  that is supported for sliding movement relative to the housing  142   b  in a direction parallel to the axis of rotation of the input shaft. Disposed between the two gear assemblies  288   b  and  290   b  on the input shaft  280   b  is a control portion  310  of the input shaft. The control portion  310  includes two circumferential grooves  312  and  314  spaced axially from each other. The gearbox  310  also includes a locator pin  316 . The locator pin  316  is supported on the housing  142   b  for in-and-out (radial) sliding movement relative to the housing and to the input shaft  280   b.    
     When the locator pin  316  is in the first groove  312  on the input shaft  280   b , as shown in  FIG. 13 , the first gear assembly  288   b  on the input shaft  280   b  is in meshing engagement with the output bevel gear  210   b . As a result, rotation of the input shaft  280   b  in a first direction about the axis  282   b  results in rotation of the output bevel gear  210   b , and the lead screw  92   b , in a first direction of rotation about the drive axis  96   b.    
     The locator pin  316  can be pulled out of the first groove  312  against the bias of a spring  318  to enable the input shaft  280   b  to be moved axially until the second groove  314  is located radially inward of the locator pin. The locator pin  316  can then be released and the spring  318  will hold it in the second groove  314 . In this position, the second gear assembly  290   b  on the input shaft  280   b  is in meshing engagement with the output bevel gear  210   b . Therefore, rotation of the input shaft  280   b  in the first direction about the axis  282   b  results in rotation of the output bevel gear  210   b , and the lead screw  92   b , in a second or opposite direction of rotation about the drive axis  96   b.    
     As a result, the bed end  14  to which the gearbox  140   b  is attached can be used at either end of the bed  10 , and still provide simultaneous upward or downward movement at both bed ends  14  and  14   a , simply by moving the input shaft  280   b  axially from one position to the other. Therefore, a bed  10 , having two identical bed ends with gearboxes  140   b  of the type shown in  FIG. 13 , can use the two bed ends interchangeably simply by adjusting the gearbox as described above. 
       FIGS. 14–17  illustrate some alternative corner plate (bracket) designs for use in the head end  14  or foot end  14   a  of the bed  10 . The corner plates shown in  FIGS. 14–17  can be used with other bed ends, and, specifically, with other bed ends that do not have one of the gearbox designs  140 ,  140   a  or  140   b , or the elevating mechanism described above. The corner plates are designed to enable a bed end to which the corner plates are attached, to be reversed front to back and still function to support a spring assembly of the bed. This feature makes the bed ends more easily used at either end of the bed  10 . 
     The corner plates are shown with bed ends  14   b ,  14   c , and  14   d  that are similar in construction and operation to the bed end  14 . The bed end  14   b  ( FIG. 14 ) includes first and second corner plates  320  and  322  that are mirror images of each other and that extend from first and second opposite major side surfaces  324  and  326  of the bed end  14   b.    
     When the bed end  14   b  is assembled in a bed  10  so that the first corner plate  320  is to be used (for example with a frame rail or a spring assembly shown partially at  328 ), the first corner plate  320  is uncovered. A wall protector  330  is placed over the unused second corner plate  322 . As a result, the first corner plate  320  is available for use, and the second corner plate  322  is protected and covered to prevent contact with the wall if the bed end  14   b  is placed with the second corner plate facing the wall. 
     When the bed end  14   b  is assembled in a bed  10  so that the second corner plate  322  is to be used, the second corner plate is uncovered (not shown). The wall protector  330  is placed over the unused first corner plate  320 . As a result, the second corner plate  322  is available for use, and the first corner plate  320  is protected from contact with the wall. 
     In this manner, the bed end  14   b  can be assembled in a bed  10  so that either the first major side surface  324  or the second major side surface  326  of the bed end faces the other parts of the assembled bed  10 , and a corner plate  320  and  322  will be available to support the spring assembly or frame rails  328  of the bed. 
     The bed end  14   c  ( FIG. 15 ) includes a corner plate assembly  332  including first and second corner plates  334  and  336  that are mirror images of each other and that are extendible from first and second opposite major side surfaces  338  and  340  of the bed end. The corner plate assembly  332  includes a central portion  342  that is fixed by rivets  356 , or in another manner, to a side surface  348  of the bed end  14   c.    
     The first corner plate  334  is hinged to the central portion  342 . The first corner plate  334  is pivotally movable between a first position in which it projects from the first major side surface  38  of the bed end  14   c  as shown in  FIG. 15 , and a second position (not shown) in which the first corner plate lies flat against the first major side surface. 
     The second corner plate  336  is also hinged to the central portion  342 . The second corner plate  336  is pivotally movable between a first position in which it projects from the second major side surface  340  of the bed end  14   c  as shown in  FIG. 15 , and a second position (not shown) in which the second corner plate lies flat against the second major side surface. 
     When the bed end  14   c  is to be assembled in a bed  10  with the first major side surface  338  facing the opposite end of the bed, the first corner plate  334  is swung into the operative position shown in  FIG. 15 . The frame rail or spring assembly shown partially at  328  is attached to the first corner plate  334 . When this is done, the second corner plate  336  can be laid flat against the second major side surface  340  of the bed end  14   c , out of the way. 
     When the bed end  14   c  is to be assembled in a bed  10  with the second major side surface  340  facing the opposite end of the bed, the second corner plate  336  is swung into the operative position shown in  FIG. 15 . A frame rail or spring assembly such as shown partially at  328  is attached to the second corner plate  336 . When this is done, the first corner plate  334  can be laid flat against the first major side surface  338  of the bed end  14   c , out of the way. 
     In this manner, the bed end  14   c  can be assembled in a bed  10  so that either the first major side surface  338  or the second major side surface  340  of the bed end faces the other parts of the assembled bed, and a corner plate  334  or  336  will be available to support the spring assembly or frame rails  328  of the bed. 
     The bed end  14   d  ( FIG. 16 ) includes a single corner plate  350  that is movable between first and second opposite major side surfaces  352  and  354  of the bed end  14   d . The bed end has two support pins  356  for supporting the corner plate  350 . The support pins  356  project from the side  358  of the bed end  14   d . 
     The bed end  14   d  also has a lock member indicated schematically at  360 . The lock member  360  may be a pin, for example, that is movable vertically on the bed end  14   d  along a slot  362 . The corner plate  350  has two notches  364  for receiving the support pins  356  on the bed end  14   d.    
     When the bed end  14   d  is assembled in a bed  10  so that the corner plate  350  is to be used projecting from the first major side surface  352  of the bed end (for example with a frame rail or a spring assembly shown partially at  328 ), the corner plate  350  is assembled as shown attached in  FIG. 16  with the pins  356  received in the notches  364 . The lock member  360  is moved into a locking position against the corner plate  350  to hold the corner plate in position on the bed end  14   d.    
     When the bed end  14   d  is assembled in a bed  10  so that the corner plate  350  is to be used projecting from the second major side surface  354  of the bed end, the corner plate is removed and switched to the other side of the bed end, as shown to the left in  FIG. 16 . The corner plate  350  is hooked onto the support pins  356 , and the locking mechanism  360  is used to hold the corner plate in that position on the bed end  14   d.    
     In this manner, the bed end  14   d  can be assembled in a bed  10  so that either the first major side surface  352  or the second major side surface  354  of the bed end faces the other parts of the assembled bed, and a corner plate  350  will be available to support the spring assembly or frame rails  328  of the bed. 
       FIG. 17  illustrates the use of the bed end  14   d  with a spring assembly or frame rail  370  that has notches for receiving the support pins  356  on the bed end. In this case, a separate corner plate, such as the corner plate  350 , is not needed. The support pins  356  function as the reversible corner plate. The spring assembly or frame rail  370  is supportable from either major side surface  352  or  354  of the bed end  14   d.    
     The parts of the bed end  14  shown in  FIGS. 1–6  are structural and operational parts for controlling at least one operational aspect of the bed, specifically, elevation of the bed. A bed end  14  in accordance with the present invention also includes a bed end cover for enclosing and covering the operational and structural parts. Several alternative covers are shown, in  FIGS. 18–21 . 
     The preferred material for these bed end covers is an engineered plastic. The selected material should be washable without being affected by water or solvents and without absorbing moisture. The selected material should also be scratch resistant, impact resistant, and ultraviolet resistant. Also, the material should be able to be molded or extruded with a single color throughout. Suitable materials include but are not limited to HDPE, ABS, and PVC. 
     The materials typically used for prior art decorative/covering panels in home care adjustable beds are paper or fiberboard covered in vinyl laminate. This material can scratch completely through the laminate, absorbs moisture when washed, does not have high impact resistance, and is not ultraviolet resistant. In addition, such a cover is manufactured by dropping the various panels of the cover into a fixture, then screwing or gluing them together. This is a time and labor-intensive operation. 
     An engineered plastic bed end cover is easier to handle, because it is impact and scratch resistant. It is also quicker to assemble in the plant. It is also washable when returned from home use to the dealer, for use by another patient, as is required. It is cost effective to manufacture, more durable, and stronger. In addition, the use of molded plastic for the bed end cover allows for color variations and therefore more artistic quality to the bed end, as well as different physical profiles or configurations for the bed end. 
     The cover  400  ( FIGS. 18 and 19 ) is one example of a plastic bed end cover that is constructed in accordance with the present invention. The cover  400  is a hollow cover for enclosing and covering the operational and structural assembly shown in  FIG. 2 . This cover  400  is extremely easy to assemble to the structural and operational parts of the bed end  14  as shown in  FIG. 2 , for example. It is also easy to manufacture and handle. 
     The cover  400  is a one-piece plastic cover having an interior major side panel  402  that faces inward toward the opposite end of the bed  10  when assembled, and an opposite exterior major side panel  404 . The cover  400  is preferably made by blow molding. A preferred material is HDPE (high density polyethylene). 
     The cover  400  also has an upper edge portion  406  interconnecting the interior and exterior major side panel, panels  402  and  404 . First and second opposite side edge portions  408  and  410  of the cover  400  interconnect the interior and exterior major side panels  402  and  404  adjacent the first and second legs (shown in phantom in  FIG. 18 ) of the bed end. The cover  400  further has a lower edge portion  412  extending between the first and second opposite side edge portions  408  and  410 . The cover  400  has an open bottom edge  414  for enabling sliding movement of the hollow cover over the operational and structural assembly in a direction between the upper edge portion  406  and the lower edge portion  412  of the cover (as indicated by the arrow  416 ). 
     The cover  400  illustrated in  FIGS. 18 and 19  has two optional openings  418  extending through the bed end cover between the interior major side panel  402  and the exterior major side panel  404 . The two openings  418  are disposed adjacent the upper edge portion  406  of the cover  400 . Each one of the two openings  418  has a lower edge  420  that extends parallel to the lower edge portion  412  of the cover  400 . As a result, a supporting assembly, such as a trapeze (not shown), can be clamped onto the bed end  14  between the lower edge  420  of one of the openings  418 , and the lower edge portion  412  of the cover  400 . 
     The cover  430  ( FIG. 20 ) is another example of a plastic bed end cover that is constructed in accordance with the present invention. The cover  430  is a hollow cover for enclosing and covering the operational and structural assembly or parts of a bed end. The cover  430  has a three-piece plastic construction including a central panel  432  and two identical end caps  433  (only one of which is shown). 
     The central panel  432  is a one-piece extrusion preferably made from PVC. The central panel  432  includes an interior major side panel  434  that faces the opposite end of the bed  10  when assembled, and an opposite exterior major side panel  436 . The panels  434  and  436  are joined by an upper edge panel  438  in an upside-down U-shaped configuration to form the central panel  432 . 
     The interior major side panel  434  has a planar configuration with a rectangular rib  440  forming a bottom end portion of the panel. Similarly, the exterior major side panel  436  has a planar configuration with a rectangular rib  442  forming a bottom end portion of the panel. The upper edge panel  438  forms a similar rectangular configuration with the top edge portions  444  and  446  of the interior and exterior major side panels  434  and  436 , respectively. 
     The end caps  433  may be made from ABS. The end cap  433  has a generally planar configuration. The end cap  433  has three flanges  450 ,  452  and  454  that matingly engage three edges,  456  of the central panel  432 , to secure the end cap to the central panel. The end cap  433  has a more rigid construction than the central panel  432 , and, as a result, can help to rigidify the assembled cover  430 . 
     The cover  430  has an open bottom edge  462  for enabling sliding movement of the hollow cover over the operational and structural assembly in a direction between the upper edge panel  438  and the bottom edge of the cover, as indicated by the arrow  464 . 
     This cover  430  is therefore easy to assemble to the structural and operational parts of the bed end  14  as shown in  FIG. 2 , for example. It is also easy to manufacture and handle, and has the other advantages discussed above with reference to the embodiment of  FIGS. 18 and 19 . 
     The cover  470  ( FIG. 20 ) is a third example of a plastic bed end cover that is constructed in accordance with the present invention. The cover  470  is a hollow cover for enclosing and covering the operational and structural assembly. 
     The cover  470  is similar to the cover  430  ( FIG. 20 ) with the exception that the central panel  472  in the cover  430  is made from three pieces, not one. Specifically, the central panel  470  is formed as an interior major side panel  474 , an exterior major side panel  476 , and an upper edge panel  478 . The three panels  474 – 478  when joined together to form the central panel  472  have an upside-down U-shaped configuration. The cover  470  otherwise has the all advantages and feature described above with respect to the cover  430  ( FIG. 20 ). 
     From the above description of the invention, those skilled in the art will perceive improvements, changes, and modifications in the invention. Such improvements, changes, and modifications within the skill of the art are intended to be included within the scope of the appended claims.