Patent Publication Number: US-2022232969-A1

Title: Over bed table with enhanced base

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to over bed tables (“OBT”), and more specifically to bases for OBTs. 
     Over bed tables are in widespread use in hospitals and other patient care facilities where patients are treated in beds. OBTs provide a convenient work surface that can be removable situated over a patient&#39;s bed. Conventional OBTs include casters, wheels are other rolling components and are easily movable into position over the patient bed from the side with a base that extends under the patient bed. There is a consistent problem with hospital and other patient beds in use today and it involves the extremely low clearance of many manufacturers&#39; beds. This low clearance is due to the overall form and function of these beds, but of particular concern is the use of OBTs with patient beds that have a “5th wheel” or “drive wheels”. In these types of patient beds, there is a “5th wheel” located either in the center or close to the center of the bed or two drive wheels somewhere in-between the four casters located on or about the four corners of the bed. In all of these configurations, the 5th wheel or drive wheels (collectively referred to as “under-bed wheels”) are intended for use during patient transport only to make the transport easier on the staff by using the wheels as a fulcrum when turning corners etc. As a result, under-bed wheels are typically configured to be raised and lowered. When a patient is being transported in the patient bed, the under-bed wheels are lowered for use. However, when a patient is in their room, the 5th wheel or drive wheels are disengaged and lifted off the floor so the four primary casters can sit evenly and level with the floor. Although under-bed wheel specifications vary from bed to bed, even when raised, under-bed wheels can have as little as 1″ of clearance from the bottom of the under-bed wheel to the floor. 
     As a result of the limited clearance, current OBT offerings do not work well with patient beds that incorporate under-bed wheels. As noted above, conventional OBT offerings include a base that is fitted under the patient bed when the OBT is moved into position for use over the patient bed. Current OBT base offerings run into the 5th wheel or the drive wheels even when raised. Further, the placement of these under-bed wheels make the use of OBTs almost impossible, and in many cases the OBTs purchased do not work at all. The reason for this is that the base of the OBT must be placed either fore or aft of the under-bed wheel(s), this creates the issue of the OBT top being either too close to the patient or too far away to be comfortably used. Conventional OBTs have a variety of different base configuration. For example, some bases are U-shaped, with the opening of the “U” facing toward the patient bed (See  FIG. 1A ). Other bases are H-shaped with the openings in the “H” facing fore and aft (See  FIG. 1B ). Still other bases are C-shaped and can be oriented with the opening of the “C” facing fore or aft (See  FIG. 1C ). None of these configurations work well with patient beds that include under-bed wheels. If a U-shaped base is used, the OBT can be positioned fore or aft of the under-bed wheels or so that the legs straddle the under-bed wheels. Positioning the base fore of the under-bed wheels limits movement of the OBT in the aft direction, which is likely to cause the OBT to be too close to the patient. Positioning the base aft of the under-bed wheels limits movement of the OBT in the fore direction, which is likely to cause the OBT to be too far from the patient. Positioning the base to straddle the under-bed wheels will capture the under-bed wheels between the legs and severely limit fore and aft movement of the OBT. If an H-shaped base configuration is used, the OBT must be positioned so that the inner end of the “H” is not aligned with any under-bed wheels (e.g. fore or aft of the under-wheels) before the OBT can be moved into position over the bed. Once the OBT has been pushed into position, it can be moved fore or aft until the base abuts the under-bed wheels. Although the “H” configuration allows a bit more movement in the fore and aft position than a U-shape base, an H-shaped base can create issues in a “Crash” situation when the patient is coding (life or death emergency situation) when the base is positioned so that the under-bed wheels are positioned with the one of the openings in the “H”. In the rush and frenzy to save the patient, the OBT base can become entangled with the 5th or drive wheels when seconds count. A C-shaped base suffers from much the same issues as the H-shaped base. Fore and aft movement of the OBT is limited by the under-bed wheels and the under-bed wheels can become entangled in the opening of the “C”, thereby making it difficult to remove the OBT from the patient bed in emergency situations. Hospitals know this full well so OBTs with H-shaped and C-shaped bases are generally not used with these patient beds having under-bed wheels. 
     As a result of the foregoing, there remains room for improvement in the field of OBTs, including a long-felt and unmet need for an OBT that is more suitable for use with patient beds that include retractable under-bed wheels, such as a 5th wheel or drive wheels. 
     SUMMARY OF THE INVENTION 
     The present invention provides an over bed table (“OBT”) with a base specially configured for use with patient beds having retractable under-bed wheels. The OBT includes a longitudinally-extended base, a column extending upwardly from one end of the base and a table top mounted atop the column and extending in a cantilevered manner over the base. The base includes a longitudinal central portion, a pair of inner wings that extend from opposite sides of the central portion adjacent the column and a pair of outer wings that extend from opposite sides of the central portion opposite the column. The central portion has a profile low enough to pass below the under-bed wheels and each of the wings has a caster portion of sufficient height to accommodate caster, wheels or other rolling elements there beneath. 
     In one embodiment, the outer wings extend from the central portion at an angle to the longitudinal extent of the central portion. For example, the outer wings may extend from the central portion at an angle of between about 95 and about 150. In one embodiment, the inner wings extend at an angle of about 90 degrees from the longitudinal extent of the central portion. 
     In one embodiment, each outer wing includes a low-profile extension portion that extends from the central portion and a transition portion that bridges between the low-profile extension portion and the raised-profile caster portion. The transition portion defines a surface that is disposed as an angle to the central portion, for example, at an angle of between about 15 and about 90. 
     In one embodiment, the central portion is of sufficient length that the raised-profile portions of the outer wings are laterally offset beyond the under-bed wheel when the OBT is in a fully-inserted position over the bed. In this position, the OBT can be moved fore and aft by the patient with the central portion passing under the raised under-bed wheel without interference. 
     In one embodiment, all of the surfaces of the outer wings that are of sufficient height to engage a raised under-bed wheel are arranged at an angle to the longitudinal extent of the central portion. As a result, the angled surfaces of the outer wings facilitate removal of the over bed table from beneath the bed in the lateral direction. This can be particularly helpful in emergency situations. 
     In one embodiment, the base includes a one-piece unitary structural fabricated from sheet or plate stock. The central portion, inner wings and outer wings may, for example, be laser cut from a single sheet or plate stock. After cutting, the inner and outer wings of the preform may be bent to form the extension portions, the transition portions and the caster portions. 
     In one embodiment, the outer wings include compound angles that facilitate rapid removal of the OBT in emergency situations. The transition portion of each outer wing may be oriented at an angle of about 5 degrees to about 60 degrees with respect to the longitudinal extent of the central portion. The outer edge of each outer wing caster portion may be oriented at an angle of about 5 degrees to about 60 degrees. The lateral edge of each outer wing caster portion may be oriented at an angle of about 95 degrees to about 150 degrees. The medial edge of each outer wing caster portion may be oriented at an angle of about 95 degrees to about 150 degrees. 
     The present invention provides a stable base for an OBT table that facilitates use with patient beds that include retractable under-bed wheels, such as 5 th  wheels or drive wheels. The low profile central portion of the base is configured to pass below a raised under-bed wheel. As a result, once the OBT has been pushed into place over the patient bed, the outer wings will be beyond the under-bed wheels and it will be possible to move the OBT fore and aft without interference from the under-bed wheels. The use of wings with a raised-profile allows the base to include casters, wheels or other rolling components of sufficient size to provide smooth and easy rolling movement of the OBT along the floor. By minimizing the wings, the portions of the base that are high enough to engage the raised under-bed wheel are minimized, thereby reducing the likelihood of interference between the base and the under-bed wheel. Further, the outer wings (i.e. the wings that extend under the bed) are configured with angled surfaces that facilitate insertion and removal of the OBT from beneath a patient bed. In the event that the outer wings do come into engagement with the under-bed wheel as the OBT is being moved in a lateral direction (e.g. roughly perpendicular to the length of the patient bed), the angled surfaces help to guide the base around the under-bed wheel. This can be particularly helpful in emergency situations when it is important to remove the OBT from beneath the patient bed as quickly as possible. 
     These and other objects, advantages, and features of the invention will be more fully understood and appreciated by reference to the description of the current embodiment and the drawings. 
     Before the embodiments of the invention are explained in detail, it is to be understood that the invention is not limited to the details of operation or to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention may be implemented in various other embodiments and of being practiced or being carried out in alternative ways not expressly disclosed herein. Also, it is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of “including” and “comprising” and variations thereof is meant to encompass the items listed thereafter and equivalents thereof as well as additional items and equivalents thereof. Further, enumeration may be used in the description of various embodiments. Unless otherwise expressly stated, the use of enumeration should not be construed as limiting the invention to any specific order or number of components. Nor should the use of enumeration be construed as excluding from the scope of the invention any additional steps or components that might be combined with or into the enumerated steps or components. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is an image of a portion of an OBT having a conventional U-shaped base. 
         FIG. 1B  is an image of a portion of an OBT having a conventional H-shaped base. 
         FIG. 1C  is an image of a portion of an OBT having a conventional C-shaped base. 
         FIG. 2  is a perspective view of an over bed table having a base in accordance with a current embodiment of the present invention. 
         FIG. 3  is a left side view of the OBT. 
         FIG. 4  is a front view of the OBT 
         FIG. 5  is a top plan view of a base preform. 
         FIG. 6  is a bottom perspective view of the base. 
         FIG. 7  is a bottom plan view of the base. 
         FIG. 8  is a left side view of the base. 
         FIG. 9  is a front view of the base. 
         FIG. 10  is a representational view showing the base positioned with respect to the under-bed wheel of a first patient bed. 
         FIG. 11  is a representational view showing the base positioned with respect to the under-bed wheel of a second patient bed. 
         FIGS. 12A-B  show a first alternative embodiment of the base with outer wings at a reduced angle. 
         FIGS. 13A-B  show a first alternative embodiment of the base with outer wings at an increased angle. 
         FIGS. 14A-B  show a first alternative embodiment of the base with outer wings incorporating a compound angle. 
     
    
    
     DETAILED DESCRIPTION OF THE CURRENT EMBODIMENTS 
     Overview. 
     A current embodiment of an over bed table (“OBT”) having a base in accordance with an embodiment of the present invention is show in  FIGS. 2-11  and generally designated  10 . The OBT  10  includes a base  12  that is specially configured for use with hospital and other patient beds that have retractable under-bed wheels, such as 5 th  wheels or drive wheels (See, e.g.  FIGS. 10 and 11 ). Referring now to  FIG. 1 , the base  12  include a central portion  14 , a pair of inner wings  16   a - b  and a pair of outer wings  18   a - b . The central portion  14  has an inner end that is configured to support a column  20  and table top  22  and an outer end that is configured to pass under the patient bed B. The central portion  14  has a low profile that is configured to pass under retracted under-bed wheels W. The inner wings  16   a - b  extend from opposite sides of the central portion  14  and support inner casters  70 . The outer wings  18   a - b  extend from opposite sides of the central portion  14  and support outer casters  70 . The outer wings  18   a - b  have a high enough profile to support the outer casters  70 . The outer wings  18   a - b  are arranged at angle to the longitudinal extend of the central portion to mitigate the effects of engagement between the outer wings  18   a - b  and an under-bed wheel. 
     Over Bed Table. 
     As noted above, the present invention provides base  12  for an over bed table  10  (“OBT”). The base  12  is specially configured for use with patient beds having retractable under-bed wheels. For purposes of disclosure, the base  12  is described in the context of an OBT  10  having a table top mounted to an adjustable-height column (See  FIGS. 2-4 ). The OBT  10  shown and described herein is merely exemplary and OBT bases in accordance with the present invention can be incorporated into OBTs of essentially any design and configuration. 
     Referring now to  FIG. 1 , the OBT  10  generally includes base  12 , column  20  and table top  22 . In this embodiment, the column  20  is a conventional telescopic column including a lower section  30  that is secured to the base  12  and an upper section  32  that is telescopically fitted over the lower section  30 . A wide range of telescopic columns are available on the market. The present invention may be incorporated into OBTs that do not include a telescopic column. For example, the column may be of fixed length or may be extend and retracted through arrangements other than telescopic arrangements. In this embodiment, the table top  22  is mounted atop the upper section  32  of the column  20  in a cantilevered arrangement. As shown, the table top  22  extends from the column  20  parallel to the general longitudinal extent of the base  12 . The illustrated table top  22  is merely exemplary and the OBT may be fitted with a wide range of alternative table tops, including table tops that present a work surface and others that include one or more drawers, shelves and/or other features and accessories. 
     Referring now to  FIGS. 6-9 , the base  12  of the illustrated embodiment generally includes a longitudinal central portion  14 , a pair of inner wings  16   a - b  that extend from opposite sides of the central portion  14  adjacent the column  20  and a pair of outer wings  18   a - b  that extend from opposite sides of the central portion  14  near the end of the central portion  14  opposite the column  20 . As perhaps best shown in  FIGS. 6 and 7 , the central portion  14  is a longitudinally extending structure having an inner end and an outer end. In this embodiment, the central portion  14  configured with an inner segment  40 , a low profile outer segment  42  and a height transition segment  44  joining the inner segment  40  and the outer segment  42 . In this embodiment, the inner segment  40  has a relatively high profile and is of about the same height as the inner wings  16   a - b , which as described in more detail is selected to accommodate casters, wheels or other rolling components (See  FIGS. 8 and 9 ). The outer segment  42  has a relatively lower profile being configured so that it is capable of passing under a raised under-bed wheel. For example, in one implementation, the outer segment  42  is configured to extend parallel to the floor with its bottom surface extending about ⅜″ off the floor (See  FIGS. 3 and 4 ). The height of the outer segment  42  above the floor may vary from application to application depending, for example, on the amount of clearance available beneath the under-bed wheels. As perhaps best shown in  FIGS. 3 and 8 , the transition segment  44  joins the inner segment  40  and the outer segment  42  bridging the height difference there between. Although the angle at which the transition segments  44  extends between the inner segment  40  and the outer segment  42  may vary, the transition segment  44  of the illustrated embodiment extends between at an angle of about 45 degrees or at an angle in the range of about 5 degrees to about 90 degrees. 
     The central portion  14  of the illustrated embodiment is of sufficient length that the outer wings  18   a - b  are beyond the under-bed wheel W when the OBT  10  is in a fully-inserted position over the patient bed B. In this position, the OBT  10  can be freely moved fore and aft relative to the bed B, for example, by the patient, with the low profile outer segment  42  of the central portion  14  passing under the raised under-bed wheel W without interference.  FIG. 3  includes a broken line W′ delineating a range of potential positions for the under-bed wheel. As shown the outer wings  18   a - b  are offset beyond the under-bed wheel W. In the illustrated embodiment, the transition segment  52  of each outer wing  18   a - b  is spaced apart from the inner end of the central portion a distance of at least 24 inches in a direction extending parallel to the longitudinal extent of the central portion  20 . It should be understood that this spacing is primarily a function of the length of the central portion  20 , the angle of the outer wings  18   a - b , the length of the extension segment  52 , and the angle of the transition segment  52 , and that these factors may be varied to provide the desired spacing. This spacing is merely exemplary and the spacing may vary from application to application depending in part on the position of the under-bed wheel(s). 
     In the illustrated embodiment, the inner wings  16   a - b  extend at an angle of about 90 degrees to the longitudinal extent L of the central portion  14 . However, the inner wings  16   a - b  may extend from the central portion  14  at other angles. The inner wings  16   a - b  are configured with sufficient height to accommodate caster, wheels or other rolling elements there beneath. In the illustrated embodiment, the inner wings  16   a - b  have an upper surface with a height of about 1.94 inches above the floor. The height may have, however, from application to application. Given that the inner wings  16   a - b  do not pass under the patient bed B, the height of the inner wings  16   a - b  can be selected without concern for engagement with an under-bed wheel. In this embodiment, the inner wings  16   a - d  are of essentially the same height as the inner segment  40  of the central portion  14 . However, there may, in alternative embodiments, be variation between the height of the inner wings  16   a - b  and the height of the inner segment  40 , if desired. 
     The outer wings  18   a - d  of the illustrated embodiment extend from the free end of the outer segment  42  of the central portion  14 . As shown, the outer wings  18   a - d  extend at an angle to the longitudinal extent of the central portion  14 . For example, the outer wings  18   a - d  may extend from the central portion  14  at an angle of between about 95 degrees and about 150 degrees from the longitudinal extent of the central portion  14 . In this embodiment, each outer wing  18   a - b  includes a caster segment  50 , an extension segment  54  and a transition segment  52 . The caster segment  50  has a relatively high profile with a height selected to accommodate casters, wheels or other rolling elements there beneath. The extension segment  54  has a low-profile with a height that is essentially the same as the outer segment  42  of the central portion  14 . The lengths of the extension segments  54  and selected so that an under-bed wheel is able to pass freely between opposite outer wings  18   a - b . For example, as shown in  FIGS. 10 and 11 , the outer wings  18   a - b  are configured to accommodate passage of an under-bed wheel W there between as the base  12  is pushed into position under or removed from beneath the bed B. In this embodiment, the extension segments  54  increase the spacing between the transition segments  54  on opposite sides of the base  12 , thereby widen the low profile section of the base  12 . The transition segment  52  joins the caster segment  50  to the extension segment  54  bridging the height difference between the low-profile extension segment  54  and the raised-profile caster segment  50 . Although the angle at which the transition segments  54  extends between the low-profile and raised-profile heights may vary, each transition segments  54  in the illustrated embodiment extends between the caster segment  50  and the extension segment  54  at an angle of about 45 degrees or at an angle in the range of about 5 degrees to about 90 degrees. Each transition portion  52  defines a surface that is disposed at an angle to the longitudinal extent of the central portion  14 . For example, the transition portions  52  may extend from the central portion  14  at an angle of between about 5 degrees and about 60 degrees from the longitudinal extent of the central portion  14 . 
     In the illustrated embodiment, all of the surfaces of the outer wings  18   a - b  that are of sufficient height to engage a raised under-bed wheel W are oriented at an angle to the longitudinal extent of the central portion  14  (See  FIG. 7 ). The angled surfaces of the outer wings  18   a - b  facilitate typical OBT movements, such as inward and outward movement in a generally lateral direction with respect to the bed B. For example, the angled outer edges  60  of the outer wings  18   a - b  facilitate insertion of the base  12  under the bed B. If the base  12  is being pushed under the bed B in a generally lateral direction and either outer edges  60  engages an under-bed wheel W, the outer edges  60  will, as a result of the angle, guide the base  12  to the side of the under-bed wheel W. As another example, the medial edges  62  of the outer wings  18   a - d  also facilitate insertion of the base  12  under the bed B. As with the outer edges  60 , the angled medial edges  62  will guide the base  12  around the under-bed wheel W if they engage when the base is being inserted in a generally lateral direction. As a further example, the lateral edges  64  of the outer wings  18   a - b  are angled to facilitate removal of the base  12  from beneath the bed B. The angled lateral edges  62  will guide the base  12  around the under-bed wheel W if they happen to engage when the base  12  is being removed in a generally lateral direction. Additionally, the angled surface of each transition segment  52  also facilitates removal of the base  12  in a generally lateral direction as the surface is able to guide the base  12  around the under-bed wheel W if they engage. As can be seen, the angled transition segments  52  and angled lateral edges  64  can be particularly beneficial when removing the OBT  10  from the bed B in a generally lateral direction, which is typical when trying to quickly remove the OBT  10  in emergency situations. 
     As noted above, the column  20  is mounted to the base  12 . In this embodiment, the lower section  30  of the column  20  is affixed to the base  12  by fasteners (not shown) that extend up through holes  34  in the base  12  into corresponding screw bosses integrated into the lower section  30  of the column  20  (See  FIG. 7 ). In this embodiment, the mounting holes  34  are defined in the inner segment  40  of the central portion  14 . This mounting structure is merely exemplary and the column  20  may be mounted to the base  12  using essentially any suitable mounting structure capable to securing the lower section  20  to the base  12 , such as welding, fasteners, clamping mechanism, post and seats just to name a few alternative options. 
     Although not shown, table top  22  may be mounted to the column  20  using essentially any suitable mounting structure. For example, a mounting plate  23  may be affixed to the upper section  32  of the column  20 , and the table top  22  can be affixed to the mounting plate  23  by fasteners. In one embodiment, the mounting plate may be joined to the upper section  32  by welding or by fasteners. It should be understood that the described table top mounting structure is merely exemplary and that the present invention may be incorporated into OBT that utilize any table top mounting structure. 
     The OBT  10  of the illustrated embodiment includes casters  70  mounted beneath the inner wings  16   a - b  and the outer wings  18   a - b . In this embodiment, caster mounts  72  are secured to the undersurfaces of each of the inner wings  16   a - b  and the outer wings  18   a - b . More specifically, in this embodiment, caster mounts  72  are affixed by welding to undersurface of the inner wings  16   a - b  and to the caster segments  50  of the outer wings  18   a - b . The caster mounts  72  may, however, be secured to the wings using any suitable attachment, such as bolts, rivets and other fastener. In this embodiment, the base  12  includes four identical casters  70 . In alternative embodiments, the casters  70  need not be identical. For example, the casters  70  mounted to the inner wings  16   a - b  may be different from the casters  70  mounted to the outer wings  18   a - b . In the illustrated embodiment, the casters  70  are selected to support the base  12  with the outer segment of the central portion  14  positioned about ⅜″ above the floor. In this embodiment, the casters have a diameter of about 36 millimeters. The caster size can be varied from application to application as desired. When the caster size is varied, the transition segments  52  can be varied to maintain the outer segment of the central portion  14  at the same height relative to the floor, or the height of the central portion  14  relative to the floor can be varied, as desired. The illustrated casters  70  are merely exemplary, and the base  12  may be fitted with alternative casters, or with wheels, rollers or other rolling components. For purposes of this disclosure, the term “caster” is intended to encompass all types of rolling components, including without limitation casters, wheels, and rollers. 
     In the illustrated embodiment, the base  12  includes a one-piece unitary structural fabricated from sheet or plate stock. For example, in one embodiment, the central portion  14 , inner wings  16   a - b  and outer wings  18   ab  may be cut as a single piece from sheet or plate stock by laser, plasma, waterjet, CNC mills/machine tools or any other manner of cutting or machining the parts or shape needed. A planar preform P cut from a single piece of plate stock is shown in  FIG. 5 . As an alternative, the base  12  may be formed from separate parts that are joined into the base, for example, by welding or other joining techniques. In one embodiment, the preform is cut from about ⅜″ plate, but the thickness may vary from application to application. As an alternative to plate or sheet stock, the preform may be manufactured from solid bar stock or other suitable materials. After cutting, the preform P may be bent at the appropriate angles to form the transition portions and the caster portions, as shown in the drawings and as described above. Bending and other shaping operations may be performed using conventional presses, brakes and other metal forming equipment to achieve the design and function as described herein and shown in the drawings. The manufacturing process could and may vary. Metal and or plastics may be used as well as stamping, forging, casting, injection molding, sintered materials, additive printing methodologies and any other manner of forming or manufacturing such product. 
     The angles and dimensions of the base  12 , including the inner portion  14 , inner wings  16   a - b  and outer wings  18   a - b  shown can vary, particularly as newly designed and released beds come to market. If bed wheel diameters increase or decrease the angles and dimensions of the base  12  may be changed. As disclosed, the lowest height and vast majority of the base  12  and the outer segment of the central portion  14  which sits under the bed is 0.75″ in height thereby leaving 0.25″ of clearance between the bottom of a retracted 5th or drive wheel and the top of the OBT base  12 . This allows the OBT to be placed directly under the 5th when or a drive wheel of a hospital bed and be used comfortably by allowing the patient or care giver to position the OBT in the fore/aft direction so the patient can easily use the OBT. 
     The OBT base of the present invention also addresses safety in patient crash situations. The very low height of the base  12  running the entire length of the outer segment of the central portion  14  combined with the angles incorporated into the outer wings  18   a - b  (which are pushed under the bed when in use) help to reduce the issues associated conventional OBT bases. The very low height OBT base  12  has a central portion  14  with an upper surface at about 0.75″ running the length of the base  12  combined with the angled geometry allows the base to be very quickly pulled from under the bed B in a crash or emergency situation. As described above, the angled portions of the outer wings  18   a - b  and the geometry of the base  12  is designed, in part, to center a 5th or drive wheel into the very low height area of the OBT base  12 . Either when inserting the OBT  10  under the bed or while performing the reverse having the OBT base  12  pulled from underneath the bed B, the geometry works similarly. This makes dealing with under-bed wheels (e.g. a 5th wheel or a drive wheel) much easier and there is a tactile feel too guiding the OBT  10  under the bed B easily without having to look for the 5th wheel or drive wheels. In an emergency, the enhanced angles that are in place for removal are designed to center around or guide away from the 5th or drive wheel much more easily than conventional OBT bases, thereby generally allowing the OBT  10  to be quickly and simply pulled from service without thought to the base  12  and the under-bed wheels W whatsoever.  FIGS. 10 and 11  show the interrelationship between the base  12  and the under-bed wheel W for two different patient bed B configurations. These two examples are merely exemplary and it should be understood that the position of under-bed wheels can vary between different models, types and styles of patient beds. The design and configuration of the present invention has been selected to work with many, if not all, currently available patient beds that incorporate under-bed wheels. 
     As noted above, the dimensions, geometry and angles of the various parts of the base  12  may vary from application. For example, the configuration of the base  12  may vary to provide enhanced performance with different types, styles and models of patent beds, whether it be different beds that are available on the market now or new beds that may be introduced in the future. To illustrate this point,  FIGS. 12A-B ,  13 A-B and  14 A-B show alternative embodiments of the present invention. In alternative embodiments, the angle of the outer wings relative to the central portion can be reduced. For example,  FIGS. 12A and 12B  show an alternative configuration in which in which the angle of the outer wings  18   a - b ′ has been reduced to about 95 degrees.  FIG. 12B  shows how a conventional under-bed wheel fits within the constraints of the base  12 ′. In other alternative embodiments, the angle of the outer wings relative to the central portion can be increased. For example,  FIGS. 13A and 13B  show an alternative configuration in which in which the angle of the outer wings  18   a - b ″ has been increased to about 150 degrees from the central portion  14 ″.  FIG. 13B  shows how a conventional under-bed wheel fits within the constraints of the base  12 ″. In other alternative embodiments, the outer wings include compound angles that further facilitate rapid removal of the OBT in emergency situations. One embodiment incorporating compound angles is shown in  FIGS. 14A and 14B . In this embodiment, the extension segments  54 ′″ and the caster segment  50 ′″ extend at different angles to further facilitate removal of the base  12 ′″ from beneath the bed. In the illustrated embodiment, the extension segments  54 ′″ extend at an angle of about 111 degrees from the longitudinal extent of the central portion  14  and the caster segments  50 ′″ extend at an angle of about 143 degrees from the extension segments  54 ′″. These angles are merely exemplary and the angles of the extension segments and the caster segment may vary in alternative embodiments. For example, the angle of the extension segments  54 ′″ may be in the range of between about 95 degrees and about 150 degrees, and the angle of the caster segments  50 ′″ may be in the range of between about 95 degrees and about 150 degrees. The use of compound angles helps to provide the transition segments  52 ′″ with relatively large angles that are effective in guiding an under-bed wheel between the outer wings  18   a - b , while at the same time providing the lateral edges  65 ′″ of the caster segments  50 ′″ with relatively large angles that are effective in guiding the base  12  around an under-bed wheel W if the under-bed wheel is located outside the region between the transition segments  52 ′″.  FIG. 14B  shows how a conventional under-bed wheel fits within the constraints of the base  12 ′″. 
     Directional terms, such as “vertical,” “horizontal,” “top,” “bottom,” “upper,” “lower,” “inner,” “inwardly,” “outer” and “outwardly,” are used to assist in describing the invention based on the orientation of the embodiments shown in the illustrations. The use of directional terms should not be interpreted to limit the invention to any specific orientation(s). 
     In addition, when a component, part or layer is referred to as being “joined with,” “on,” “engaged with,” “adhered to,” “secured to,” or “coupled to” another component, part or layer, it may be directly joined with, on, engaged with, adhered to, secured to, or coupled to the other component, part or layer, or any number of intervening components, parts or layers may be present. In contrast, when an element is referred to as being “directly joined with,” “directly on,” “directly engaged with,” “directly adhered to,” “directly secured to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between components, layers and parts should be interpreted in a like manner, such as “adjacent” versus “directly adjacent” and similar words. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
     The above description is that of current embodiments of the invention. Various alterations and changes can be made without departing from the spirit and broader aspects of the invention as defined in the appended claims, which are to be interpreted in accordance with the principles of patent law including the doctrine of equivalents. This disclosure is presented for illustrative purposes and should not be interpreted as an exhaustive description of all embodiments of the invention or to limit the scope of the claims to the specific elements illustrated or described in connection with these embodiments. For example, and without limitation, any individual element(s) of the described invention may be replaced by alternative elements that provide substantially similar functionality or otherwise provide adequate operation. This includes, for example, presently known alternative elements, such as those that might be currently known to one skilled in the art, and alternative elements that may be developed in the future, such as those that one skilled in the art might, upon development, recognize as an alternative. Further, the disclosed embodiments include a plurality of features that are described in concert and that might cooperatively provide a collection of benefits. The present invention is not limited to only those embodiments that include all of these features or that provide all of the stated benefits, except to the extent otherwise expressly set forth in the issued claims. Any reference to claim elements in the singular, for example, using the articles “a,” “an,” “the” or “said,” is not to be construed as limiting the element to the singular. Any reference to claim elements as “at least one of X, Y and Z” is meant to include any one of X, Y or Z individually, any combination of X, Y and Z, for example, X, Y, Z; X, Y; X, Z; Y, Z, and/or any other possible combination together or alone of those elements, noting that the same is open ended and can include other elements.