Abstract:
Apparatus for selectively supporting a section ( 9 ) of an articulated bed platform in a raised position relative to a frame of the bed includes a stay ( 11 ) having engagement member ( 13 ) which is able to reciprocate in a guide ( 15 ) provided on the frame. Locking means allow the engagement member ( 13 ) to be selectively engaged, such that the engagement member ( 13 ) either reciprocates in the guide ( 15 ), or is prevented from doing so. When the engagement member ( 13 ) is engaged, the stay ( 11 ) can support the bed section ( 9 ) in the raised position.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a nationalization of International Patent Application No. PCT/GB2013/051773, filed on Jul. 4, 2013, pursuant to 35 USC §371, which in turn claims benefit of priority to Patent Application No. GB1212749.4, filed on Jul. 18, 2012, the entire disclosures of which are expressly incorporated by reference herein. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to apparatus for selectively supporting a bed section, and in particular to apparatus suitable for use with a hospital bed. More particularly, the present invention relates to apparatus for supporting a section of an articulated bed platform in a raised position such that the platform can be placed in a number of different positions. 
     2. Description of the Related Technology 
     Hospital beds often include an articulated platform comprising a number of separate sections which can be independently raised, thus enabling the platform to be arranged in a number of positions to suit the needs of the occupant and/or medical staff. 
     Typically, three sections are provided along the length of the platform; a backrest section which supports the occupant&#39;s upper body, a thigh section which supports the occupant&#39;s thighs (i.e. supports the occupant between the hips and the knees) and a calf section which supports the occupant below the knees. In a typical arrangement, a first end of the backrest section (that is the end adjacent the occupant&#39;s head) can be raised such that the occupant&#39;s torso can be supported with the occupant in a sitting position. The first end of the thigh section (that is the end disposed towards the head end of the bed) is pivotally attached to the bed frame at platform level and the second end of the thigh section (that is the end disposed towards the foot end of the bed) can be raised, such that the occupant&#39;s thighs can be supported when the occupant&#39;s legs are bent at the knee. The first end of the calf section is pivotally attached to the second end of the thigh section, and the second end of the calf section can be raised from the flat platform position. 
     When the second end of the thigh section and thus the first end of the calf section are in a raised position, and the second end of the calf section is not raised, both the occupant&#39;s thighs and calves are supported when the occupant&#39;s legs are bent at the knee. This is known as the Fowler position. 
     When the second end of the thigh section and thus the first end of the calf section are in a raised position, and the second end of the calf section is also in a raised position, both the occupant&#39;s thighs and calves are supported when the occupant&#39;s calves are raised and substantially parallel to the bed frame. This is known as the vascular position. 
     When the bed is arranged in the vascular position, a support mechanism is required to support the second end of the calf section in the raised position. Known designs of calf section supports include the use of two telescopic multi-position ratchet assemblies, one disposed generally along each long side of the bed. There are however disadvantages to this solution. First, the ratchet assemblies are not strong enough. This is partially because of the construction, but also because each ratchet assembly is not linked to the other, meaning that any load applied to one side of the bed is only carried by one of the ratchets. Second, when the thigh and calf sections of the bed are lowered to the flat platform position, the ratchet assemblies extend and lock so that when the thigh section is raised again the calf section is moved directly into the vascular position. This is disadvantageous when raising the occupant&#39;s legs into the vascular position is medically contra-indicated. Third, such ratchet assemblies are difficult to clean. 
     The present invention seeks to provide an improved mechanism for supporting a section of an articulated bed platform in a raised position. 
     SUMMARY OF THE INVENTION 
     According to an aspect of the present invention, there is provided apparatus for selectively supporting a section of an articulated bed platform in a raised position relative to a frame of the bed, the apparatus including a stay having a first end including an engagement member which is able to reciprocate in guide means provided on the frame and a second end pivotally attached to the bed section, and locking means for selectively engaging the engagement member. The locking means includes a lever moveable between a first position in which the engagement member is prevented from engaging the locking means and is thus free to reciprocate in the guide means, and a second position in which the engagement member engages the locking means thus preventing the engagement member from reciprocating in the guide means and thereby enabling the stay to support the bed section in the raised position. 
     This arrangement provides a single simple mechanism for stably supporting the bed section in the raised position, and allows an operator to easily move the bed platform from a flat platform position into the Fowler position or the vascular position, or to move the platform between the Fowler position and the vascular position. Advantageously, the arrangement enables the bed to be moved from the flat platform position to the Fowler position without the bed having to be initially moved into the vascular position. 
     The engagement member may include a stay pin, and the guide means may include a plate member having a longitudinal recess in which the stay pin can reciprocate. This reciprocating action allows the bed section to be lowered (so as to present a substantially flat platform with the other bed section(s), or to place the bed platform in the Fowler position) when the stay pin is located at one end of the longitudinal recess, and raised (so as to place the bed platform in the vascular position) when the stay pin is located at the second end of the longitudinal recess. 
     The locking means may include a detent in the longitudinal recess, forming a shoulder against which the stay pin can engage to lock the stay in position. The detent may be provided at the second end of the longitudinal recess, such that the stay pin is locked in position at the second end of the longitudinal recess. The lever may be pivotable between the first and second positions, and may be shaped such that when the lever is in the first position a contact surface of the lever covers the detent, and when the lever is in the second position the detent is exposed. Thus, when the lever is in the first position the stay pin is able to reciprocate in the longitudinal recess without engaging the shoulder of the detent, and when the lever is in the second position the stay pin is able to engage the shoulder of the detent thereby locking the stay in position. 
     The lever may be biased towards the first position by biasing means, which may include a spring finger forming a part of the lever. 
     When the lever is in the second position and the stay pin is engaged with the shoulder of the detent, the lever may be moved towards the first position by a pushing force exerted by a pushing member provided on the bed section, as the bed section is lowered. This action causes the contact surface of the lever to contact the stay pin and move this away from engagement with the shoulder and out of the detent, so that the stay pin can once again reciprocate in the longitudinal recess. The contact surface of the lever again covers the detent to prevent the stay pin from engaging the shoulder of the detent once more. Thus, as an operative moves the bed platform from the vascular position to the flat position, the pushing member causes the lever to move the stay pin out of its locked position, thus enabling the stay pin to reciprocate in the longitudinal recess and enabling the bed section to be lowered or raised as required. 
     Advantageously, the stay includes a load bearing finger which, as the bed section is lowered as described above, contacts a part of the bed frame. This removes the load from the stay, thus enabling the stay pin to be moved away from engagement with the shoulder and out of the detent more easily. 
     In an embodiment, the bed section is a calf section which supports the calves of an occupant. 
     According to another aspect of the present invention, there is provided a bed including a frame and a platform, the platform including a thigh section and a calf section, wherein the thigh section has a first end pivotally attached to the frame such that a second end thereof may be raised relative to the frame, and wherein the calf section has a first end which is pivotally attached to the second end of the thigh section such that the calf section may be raised relative to the frame. The bed further includes a stay having a first end including an engagement member which is able to reciprocate in guide means provided on the frame and a second end pivotally attached to the bed section, and locking means for selectively engaging the engagement member, the locking means including a lever moveable between a first position in which the engagement member is prevented from engaging the locking means and is thus free to reciprocate in the guide means, and a second position in which the engagement member engages the locking means thus preventing the engagement member from reciprocating in the guide means and thereby enabling the stay to support the bed section in the raised position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A preferred embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: 
         FIG. 1  is a side perspective view of a bed in accordance with an embodiment of the present invention, wherein the bed platform is in the vascular position; 
         FIG. 2  is a perspective view showing the locking mechanism of the bed of  FIG. 1  in greater detail; 
         FIG. 3 a    is a cross sectional side view of part of the bed of  FIG. 1 , wherein the bed platform is in the flat position, and  FIG. 3 b    is a cross sectional side view showing a detailed part of the bed of  FIG. 3   a;    
         FIG. 4  is a cross sectional side view of the bed of  FIG. 1 , wherein the bed platform is in the Fowler position; 
         FIG. 5  is a cross sectional side view of the bed of  FIG. 1 , wherein the bed platform is in the process of being moved from the Fowler position to the vascular position; 
         FIG. 6  is a cross sectional side view of the bed of  FIG. 1 , wherein the bed platform is in the vascular position; and 
         FIG. 7  is a cross sectional side view of the bed of  FIG. 1 , wherein the bed platform is in the process of being lowered so as to re-engage the Fowler position. 
     
    
    
     The components in the drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the teachings herein. 
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the description below the phrase “first end” is used to denote the end of any component of the bed which is disposed towards the end of the bed at which an occupant&#39;s head would be positioned in normal use, and the phrase “second end” is used to denote the end of any component of the bed which is disposed towards the end of the bed at which an occupant&#39;s feet would be positioned in normal use. 
       FIG. 1  shows a bed  1  in accordance with an embodiment of the present invention. The bed  1  is suitable for use in a hospital. The bed mattress has been removed for clarity, such that the platform and the frame  3  can be seen in greater detail. The platform is articulated and comprises a backrest section  5 , a thigh section  7  and a calf section  9 . The first end of the backrest section  5  can be raised such that an occupant&#39;s torso can be supported with the occupant in a sitting position. The first end of the thigh section  7  is pivotally attached to the bed frame  3  and the second end of the thigh section  7  can be raised, such that an occupant&#39;s thighs can be supported when the occupant&#39;s legs are bent at the knee. The first end of the calf section  9  is pivotally attached to the second end of the thigh section  7 , and the second end of the calf section  9  can be raised away from the frame  3 . 
     Referring to  FIG. 2 , the mechanism by which the calf section  9  can be supported in a raised position comprises a stay  11  having a stay pin  13  at a first end and being pivotally attached to the calf section  9  at a second end (not shown in  FIG. 2 ). The stay pin  13  can reciprocate in a slot or guide  15  provided in a guide plate  17  forming part of the bed frame. The slot has a recess or detent  19  which provides a shoulder  21  with which the stay pin  13  can engage, thus enabling the stay  11  to support the calf section  9  in the raised position. 
     A lever  23  can be pivoted between two positions, one position in which the recess  19  is covered such that the stay pin  13  cannot engage against the shoulder  21 , and a second position in which the recess  19  is exposed such that the stay pin  13  can drop into the recess  19  and engage the shoulder  21 . The action of the lever  23  will be described more fully below. 
     With the exception of the thigh section  7 , the calf section  9  and the stay  11 , all other components of the bed in this embodiment exist as pairs on each side of the bed. In other embodiments, there may be provided a pair of stays, one on each side of the bed, or the bed may be provided a plurality of stays. 
     Referring now to  FIGS. 3 a  and 3 b   , these Figures show the bed platform in the flat position. The thigh section  7  can be pivotally raised by an actuator  25  of known form. The calf section  9  can be raised at its first end by the thigh section  7 , and the second end of the calf section  9  can either slide along the longitudinal member  27  of the frame, or be raised pivotally by a stay  11 . These actions place the platform in the Fowler position or the vascular position respectively, dependent on which function has been selected by the operator. A protective low friction component in the form of a calf section guide  29  is fitted to the non-pivoting end of the calf section  9 , to prevent damage to the coating of the longitudinal member  27 . Because both sides of the calf section  9  are supported by a component, that is the stay  11 , torsional stiffness of the calf section  9  is increased. 
     When thigh section  7  is raised, the calf section  9  moves in one of two ways, as described above. This is achieved by allowing the stay pin  13  of the stay  11  either to slide horizontally in the slot  15  of the guide plate  17 , or to engage against the shoulder  21  of the recess  19 . These two positions of the stay pin  13  are obtained by the operation of pivoting lever  23 . 
       FIG. 4  shows the thigh section  7  and calf section  9  of the bed with the platform in the Fowler position. When in this position, the lever  23  covers the recess  19  such that the stay pin  13  cannot engage against the shoulder  21 . The stay  11  therefore cannot drop into the recess  19  and raise the calf section  9 . The lever  23  incorporates a friction device, in this embodiment an integral spring finger element  31 , which provides enough resistance to support the free end of the stay  11 . In this position, raising the knees does not raise a patient&#39;s calves. 
     Referring now to  FIGS. 5 and 6 , when it is required to move the platform into the vascular position, first the thigh section  7  is partially raised then the calf section  9  is manually pivoted upwards, in this embodiment by hand but in other embodiments potentially with an actuator similar to actuator  25 . This action moves the stay pin  13  backwards (that is towards the foot end of the bed), thereby trapping it against the lever  23  and the projection  33  on the guide plate  17 . The force generated by this action rotates the lever  23  counter-clockwise, thereby exposing the recess  19 . Then, when the calf section  9  is lowered by the operator, the stay pin  13  drops into the recess  19  and engages against the shoulder  21 , such that the calf section  9  is supported in a raised position by the stay  11 . The thigh section  7  can be now be fully raised, if required, together with the calf section  9 , into the vascular position as shown in  FIG. 6 . 
     When the vascular position is no longer required, the bed platform can be automatically switched to the Fowler position by fully lowering the thigh section  7  and the calf section  9  and raising these sections again. Referring to  FIG. 7 , this switching action is achieved through the lever  23  being rotated clockwise by a pushing member  35  forming a part of a cross member provided on the calf section  7 . This pushing member  35  pushes against the lever  23  when the calf section  9  is lowered. At this point, the calf section guide  29  contacts the longitudinal member  27  of the frame, thus removing the load from the stay  11 . As the calf section  9 , and thus the pushing member  35 , continues to be lowered, the lever  23  is rotated clockwise. This clockwise rotation enables a contact surface  37  of the lever  23  to contact the stay pin  13 , and lift the stay pin  13  out of the recess  19 . When the sections  7 ,  9  are flat the lever  23  is again held in position and will prevent the stay pin  13  from engaging the shoulder  21 . 
     The arrangement described above provides a single mechanism which can be simply operated to stably support the calf section in the raised position. The calf section is supported by a stay which can be selectively locked in position, allowing the second end of the calf section to be selectively raised as required.