Patent Publication Number: US-8990984-B2

Title: Medical bed

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention pertains to a medical bed for examining patients. More particularly, the present invention pertains to a medical bed for examining patients in the lithotomy position. 
     2. Description of the Prior Art 
     Medical beds for placing patients into the lithotomy position are well known in the art. The lithotomy position, as understood by one having ordinary skill in the art, is when the patient assumes the supine position (i.e., with the patient laying on his/her back) and the patient&#39;s hips and knees are flexed with the legs spread apart and raised and the feet resting in straps, or stirrups. This is also referred to as the dorsosacral position, and this position is commonly used during childbirth or gynecological exams. 
     Numerous medical beds for placing the patient in the lithotomy position have been used over time. Some of the earlier medical beds were not more than essentially a padded bed and a pair of leg stirrups. 
     Over time, backrests were developed that could be inclined and leg stirrups were also provided that could be adjusted both up-and-down and side-to-side, such as shown in U.S. Pat. No. 3,318,596 to Herzog. 
     Later designs were intended to allow the medical caregiver to get closer to the patient without having to reposition the patient. For example, U.S. Pat. No. 7,536,734 to Heimbrock discloses a lithotomy medical bed having a backrest section, a footrest section, and a medial section for supporting the patient&#39;s posterior. The bed also includes foot stirrups which can be adjusted up-and-down. The backrest section can be inclined from a horizontal position, and the medial section can also be inclined from a horizontal position to support the patient. As disclosed in Heimbrock, a typical lithotomy medical bed has a removable footrest section to provide access to the patient&#39;s pelvic area for caregivers like doctors and nurses. Removal of the footrest section also allows the stirrups to be positioned below the plane of the bed to allow the patient to sit upright. Another example of this type of medical bed is disclosed in U.S. Pat. No. 7,464,421 to Goodwin et al. 
     Thus, Heimbrock provides the caregiver with access to the patient&#39;s pelvic section by removing the foot section of the bed, and does not require the patient to be repositioned on the bed. However, there still remains room for improvement. 
     U.S. Patent Application Publication No. 2008/0127421 to Hornbach et al. discloses a lithotomy bed having an inclinable backrest section and a declinable footrest section. The backrest section, footrest section, and the section for supporting the patient&#39;s posterior are all slidable (or translatable), allowing the patient to be moved closer to the caregiver atop the frame of the bed. However, the footrest section must be moved forward toward the caregiver before it can be pivoted downward. Thus, the medical bed must first be positioned with the footrest section down before the caregiver can move into position near the patient&#39;s pelvic area. 
     Accordingly, there remains a need for a lithotomy medical bed which allows the caregiver to position him or herself at the footrest-end of the bed before, or while, the patient is translated toward the end of medical bed. 
     The present invention, as detailed hereinbelow, seeks to fill this need by providing a medical bed for positioning the patient in the lithotomy position having a mattress pad including a partitioned footrest section which cascades over and down the end of the medical bed as the mattress pad is translated toward the end thereof. 
     SUMMARY OF THE INVENTION 
     The present invention provides a medical bed for positioning the patient in the lithotomy position having a mattress pad including a flexible footrest section that cascades over and down an end of the medical bed as the mattress pad is translated toward the end of the medical bed. 
     Alternatively, the present invention provides a medical bed comprising: (a) a frame having a head-end and a foot-end; (b) a mattress pad positioned atop the frame, the mattress pad having a backrest section, a medial section, and a footrest section, the backrest section being oriented toward the head-end of the frame, and the footrest section being oriented toward the foot-end of the frame, the mattress pad being translatable with respect to the frame, the footrest section including a plurality of partitioned segments that are pivotable with respect to each other; and (c) wherein the footrest section cascades down and over the foot-end of the frame when the mattress pad is translated toward the foot-end of the bed. 
     In yet another description hereof, the present invention provides a medical bed comprising: (a) a frame having a head-end and a foot-end, the frame including at least one linear track having a substantially straight section and a curvilinear section, the curvilinear section being positioned at the foot-end of the frame and extending down and over the foot-end of the frame; (b) a carriage including a plurality of slats which are pivotally engaged with each other, the carriage further including a plurality of brackets, the brackets being connected to a respective slat and at least one wheel connected to the bracket, the wheels being engaged in the linear track, whereby the carriage is translatable with respect to the track; (c) a mattress pad positioned atop the frame, the mattress pad having a backrest section, a medial section, and a footrest section, the backrest section oriented toward the head-end of the frame, and the footrest section oriented toward the foot-end of the frame, the footrest section including a plurality of partitioned segments that are pivotable with respect to each other, wherein the footrest section cascades down and over the foot-end of the frame when the carriage and mattress pad are translated toward the foot-end of the frame. 
     For a more complete understanding of the present invention, reference is made to the following detailed description and accompanying drawings. In the drawings, like reference characters refer to like parts throughout the views in which: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a first embodiment of the present invention hereof; 
         FIG. 2  is a perspective view of the medical bed with the footrest section of the mattress pad removed showing the carriage; 
         FIG. 3  is a perspective view showing the carriage and track atop the frame of the medical bed; 
         FIG. 4  is an enlarged view showing an enlarged cross-section view of a “C-shaped” track retaining a mounting bracket and wheels; 
         FIG. 5  is an enlarged view showing an enlarged cross-section view of a “U-shaped” track retaining a pair of opposed mounting brackets and wheels; 
         FIG. 6  is a perspective view of the carriage showing the slats and the mounting brackets attached thereto, and in particular, showing a carriage including four sets of mounting brackets in which the pair of mounting brackets on each side of the slats are offset from each other; 
         FIG. 7  is an exploded view of a pair of slats and four mounting brackets as oriented in the carriage shown in  FIG. 6 ; 
         FIG. 8  is a side view of the top of the frame, mattress pad, and carriage, the frame, mattress pad, and carriage being shown partially transparent to display the linear actuators, the carriage and associated linear actuator being in a retracted position; 
         FIG. 9  is a side view of the top of the frame, mattress pad, and carriage, the frame, mattress pad, and carriage being shown partially transparent to display the linear actuators, the carriage and associated linear actuator being in an extended position; 
         FIG. 10  is an enlarged partial view of the carriage, mounting brackets, and partitioned footrest section of the mattress pad; 
         FIG. 11  is a side view of the top of the frame, mattress pad, and carriage, the frame, mattress pad, and carriage being shown partially transparent to display the linear actuators, the backrest and associated linear actuator being in a retracted position; 
         FIG. 12  is a side view of the top of the frame, mattress pad, and carriage, the frame, mattress pad, and carriage being shown partially transparent to display the linear actuators, the backrest and associated linear actuator being in an extended position; 
         FIG. 13  is a schematic top view showing the mattress pad and leg stirrups in a retracted position; and 
         FIG. 14  is a schematic top view showing the mattress pad and leg stirrups in an extended position. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In accordance with the present invention and as shown generally in  FIGS. 1 and 2 , there is provided a medical bed  10  comprising a frame  12 , a carriage  14  including a plurality of slats  16  that are pivotally engaged with each other, and a mattress pad  18  positioned atop the frame  12 . 
     The frame  12  includes a support structure similar to any medical bed found in the prior art, particularly like those disclosed in U.S. Pat. No. 7,464,421 to Goodwin et al. or U.S. Pat. No. 3,318,596 to Herzog, the disclosures of which are hereby incorporated by reference. As discussed in further detail below, the frame  12  can include controls and actuators (or drive means) (not shown) for moving or adjusting particular parts of the carriage  14  and mattress pad  18 . The frame  12  has a head-end  20  and a foot-end  22 , which are appropriately named for the respective ends of the patient. 
     As shown in  FIG. 3 , the top section  24  of the frame  12  includes at least one continuous linear track  26  having a substantially straight section  28  and a curvilinear section  30  for supporting the carriage  14  and allowing the carriage  14  to slide atop the frame  12 . The curvilinear section  30  of the track  26  is positioned at the foot-end  22  of the frame  12  and extends down and over the foot-end  22  of the frame  12 . Any suitable type of track that can engage and retain a movable member is suitable for use herewith. For example, and as shown in  FIGS. 4 and 5 , the track  26  can have a cross-section that is U-shaped, C-shaped, or the like. Preferably, the track  26  has a cross-section that is a suitable rolling surface for a rolling member. The track  26  also preferably includes at least one retaining lip  32 , or wall, to retain the rolling member therein. Optionally, the track  26  can include two retaining lips  32 : one at a top edge  34  and one at a bottom edge  36  of the track  26 . The frame  12  preferably includes at least two tracks  26 : one for supporting each side of the carriage  14 . Optionally, and for reasons discussed further below, the frame  12  can include four tracks  26 : two for supporting each side of the carriage  14 . 
     The first straight section  28  of the linear track  26  can be substantially horizontal atop the frame  12 , and the curvilinear section  30  curves down and over the foot-end  22  of the frame  12 . The curvilinear section  30  can curve downward approximately 90° from the straight horizontal section  28 . Although not shown, it is contemplated herein that the curvilinear section  30  can curve, or bend, more or less than 90° with respect to the straight section  28 . In other words, the curvilinear section  30  can optionally curve outwardly from the bed  10  or back toward, and into, the frame  12  of the bed  10 . In this regard, it is contemplated that the curvilinear section  30  can even bend up to an entire 180° back into the bed  10  if so desired. 
     In an alternate embodiment not shown in the drawings, the track  26  is substantially straight along the entire length thereof, and does not include the curvilinear section  30 . Rather than curving downward as described above, the track  26  extends horizontally and substantially straight off the end  22  of the bed  10 , thereby allowing the patient to be translated toward the end  22  of the bed  10 , such as when the patient is in the prone position (i.e. laying flat with the chest down and back upward). 
     Optionally, the track  26  can also include a second straight section  38  attached to the curvilinear section  30  opposite the first straight section  28 , thereby placing the curvilinear section  30  between the two straight sections,  28  and  38 , and allowing for a greater total length of the carriage  14  that can be passed over the curvilinear section  30 . 
     As shown throughout the drawings, and particularly in  FIGS. 3 ,  6 , and  7 , a carriage  14  is provided which rides atop, and is retained by the track  26 . The carriage  14  is slidable, or translatable, along the track  26 . The carriage  14  includes a plurality of slats  16  extending from one lateral side of the medical bed  10  to the other. Each slat  16  is preferably elongated and has a rectangular planar upper surface  40  upon which the mattress pad  18  is attached, or positioned. 
     The slats  16  are pivotally engaged with each other along their adjacent lateral sides  42  allowing the carriage  14  to translate over the curvilinear section  30  of the track  26 . The slats  16  are pivotally secured to each other using any suitable mechanism that is well-known in the art, including a hinge or the like. 
     A plurality of mounting brackets  44  are provided, any number of which can be attached to a bottom surface  46  of at least some of the slats  16 . Each mounting bracket  44  has an upper surface  48  that is secured to the bottom surface  46  of the respective slat  16 . Each mounting bracket  44  also includes at least one rotatable wheel  50  that is retained within the track  26 . Each wheel  50  includes an axle  52  that permits the wheel  50  to rotate with respect to the mounting bracket  44 . The wheel  50  is rollable within the track  26 , thereby allowing the carriage  14  to slide along the track  26  as the wheels  50  rotate within the track  26 . Preferably, each mounting bracket  44  includes three rotatable wheels  50 : a lower wheel  50   a  for bearing the weight of the carriage  14 , and two upper wheels  50   b  which assist with travel through the curvilinear section  30  of track  26  and which also cooperate with the lower wheel  50   a  and to retain the wheels  50  within the track  26 . In some arrangements, the upper wheels  50   b  may also support the weight of the carriage  14 , such as when the curvilinear section  30  bends more than 90°. 
     It is understood that in order for the carriage  14  to slide properly over the curvilinear section  30  of the track  26 , the wheels  50  in the track  26  may not touch each other or they will bind together, allowing no further movement along the track  26 . There are several geometric constraints that determine whether the wheels  50  will bind, for instance, the diameter of the wheels  50 , the radius of curvature of the curvilinear section  30  of the track  26 , and the width of the slats  16 . In order to ensure adequate performance and comfort of the translating motion of the mattress pad  18 , it may be desirable to provide four tracks  26 : two tracks  26  for each lateral end of the slats  16 . In this regard, mounting brackets  44  can be mounted to the bottom surface  46  of the slats  16  in a staggered offset manner as shown in  FIG. 6 . By alternating the orientation of the wheels  50  of the successive mounting brackets  44  into the respective alternating tracks  26  (not shown), the distance between the wheels  50  can be significantly increased. This results in a larger permissible wheel  50  diameter and narrower slats  16 , both of which contribute to a more comfortable and smoother translation of the mattress pad  18  over the curvilinear section  30 . 
     As shown in  FIGS. 8 and 9 , the carriage  14  can be translated along the track  26  using any suitable means which are well-known in the art. Preferably, a first linear actuator  54  is connected to and extends between the carriage  14  and the frame  12  of the bed  10 . The first linear actuator  54  can be a mechanical actuator, a hydraulic actuator, a pneumatic actuator, or the like. If the linear actuator  54  is hydraulic or pneumatic, it is preferably a cylinder having a piston. If the linear actuator  54  is mechanical, it can comprise any suitable device which is well-known to deliver linear motion, including but not limited to, screw devices (e.g., a lead screw, a ballscrew, a screw jack, a roller screw), wheel-and-axle devices (e.g., rack and pinion, chain drive, belt drive), and cam actuators. Preferably, the linear actuator  54  is a leadscrew, which is known to include an internally-threaded nut (or block  56 , shaft, etc.), and a rotating externally-threaded shaft. The threaded nut cannot rotate as a result of external forces, and as the threaded shaft rotates within the nut, the nut is driven up and down along the length of the shaft. 
     As shown in  FIGS. 8 and 9 , there is provided a block  56  having an internally-threaded bore, and the block  56  is secured to the carriage  14 . There is also provided an externally-threaded drive shaft  58  that is threaded within the bore of the block  56 . As the drive shaft  58  is rotated (such as by a motor), the block  56  is driven along the length of the drive shaft, thereby translating the carriage  14  and mattress pad  18  back-and-forth along the top section  24  of the medical bed  10 . 
     There is also provided any suitable electrical control mechanisms or circuitry (not shown) to effectuate the caregiver&#39;s manual inputs to control the linear actuator  54  (as well any additional linear actuators described below). In this regard, the caregiver can easily and effortlessly slide the carriage  14  along the track  26  in either direction in order to position the patient as desired. 
     Also included is a mattress pad  18  positioned atop the frame  12  of the medical bed  10 . The mattress pad  18  includes a backrest section  60 , a medial section  64 , and a footrest section  62 . The backrest section  60  is oriented toward the head-end  20  of the frame  12 , and the footrest section  62  is oriented toward the foot-end  22  of the frame  12 . Preferably, the medial section  64  and the footrest section  62  are positioned atop the carriage  14 . The backrest section  60 , the medial section  64 , and the footrest section  62  can all be pivotable with respect to each other. The backrest section  60 , the medial section  64 , and the footrest section  62  each comprise suitable materials and cushioning for supporting a patient and are of the type that is well-known in the art. 
     The footrest section  62  includes a plurality of partitioned segments  66  that are pivotable with respect to each other, wherein the footrest section  62  can cascade down and over the foot-end  22  of the frame  12  when the carriage  14  and mattress pad  18  are translated toward the foot-end  22 . 
     As shown in greater detail in  FIG. 10 , each partitioned segment  66  includes an upper surface  68  and a pair of downward-extending side surfaces  70 . There is an interior angle θ between the upper surface  68  and each side surface  70  that is less than 90° so that the side surfaces  70  can extend generally toward each other as the side surfaces  70  extend downward from the upper surface  68 . A void is left between the side surfaces  70  of the adjacent segments  66  allowing the segments  66  to pivot downwardly over the foot-end  22  of the frame  12 . The angle θ will vary depending upon a number of factors, including the thickness of the mattress pad  18  and the angle of the radius of curvature along the curvilinear portion of the track  26 . Preferably, angle θ is 75° or less. 
     Optionally, the frame  12  can include at least a second (not shown) and a third linear actuator  72  for assisting the caregiver in positioning the patient properly. For example, the second linear actuator can be used to adjust the height of the bed  10  by driving the top  24  of the frame  12  (and carriage  14  and mattress pad  18 ) up or down as desired. 
     Furthermore, and as shown in  FIGS. 11 and 12 , a third linear actuator  72  can be used to incline or decline the backrest section  60  of the mattress pad  18 . When the third linear actuator  72  is provided, the backrest section  60  can include a frame section  76  that remains horizontal and a pivotable cushion section  78  that can pivot upwardly. There is also provided a pair of scissor extensions  80  that each extend from the end  82  of the third linear actuator  72 : one scissor extension  80  connected from the end  82  of the third linear actuator  72  to the frame section  76  of the backrest section  60 ; and one scissor extension  80  connected from the end  82  of the third linear actuator  72  to the cushion section  78  of the backrest section  60 . As the third linear actuator  72  is extended, the third linear actuator  72  drives the cushion section  78  upwardly from the frame section  76 , thereby inclining the mattress pad  18  at the head-end  20  of the frame  12 . 
     Furthermore, there is provided a pair of leg stirrups  84  for supporting the patient&#39;s legs. The leg stirrups  84  are operably connected to the mattress pad  18  and/or carriage  14  whereby the leg stirrups  84  slide outwardly from the foot-end  22  of the frame  12  and away from each other when the mattress pad  18  is translated toward the foot-end  22  of the frame  12 . As shown in  FIGS. 13 and 14 , each leg stirrup  84  can include a slot  86  that pivots about a fixed point  88  on the frame  12 . The fixed point  88  can be any suitable part of the frame  12  that does not move with respect to the frame  12  and which extends through the slot  86  in the leg stirrup  84 . Preferably, each leg stirrup  84  is connected to the mattress pad  18  and/or carriage  14  at an end  90  of the leg stirrup  84  so that the translational movement thereof will also drive the leg stirrups  84  forward. The slot  86  can be straight or curved so long as the leg stirrups  84  will extend away from each other when the leg stirrups  84  are driven outwardly from the frame  12  to properly position the patient. 
     It is to be understood that the leg stirrups  84  can also be configured to be driven upwardly while they extend outwardly. Optionally, the leg stirrups  84  can be connected to, and driven by, a fourth linear actuator (not shown) so that the leg stirrups  84  can be operated independently of the translational mattress pad  18  movement. 
     According to the invention described above, a medical bed is provided which allows the caregiver to quickly and easily adjust the position of the patient. And more particularly, to adjust the position of the patient after the caregiver is already in proper position to begin the procedure or examination.