Abstract:
This invention relates to portable devices and their methods of use, which assist in moving patients positioned on beds, gurneys, or other such patient supports. More particularly, the invention relates to portable devices and their methods of use, which enable a single health care worker to perform a patient pullup, roll the patient to a desired position, reposition the patient, or laterally transfer the patient to another patient support.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application is a continuation in part of U.S. application Ser. No. 09/307,637 filed May 7, 1999 now abandoned, which is a continuation in part of U.S. application Ser. No. 09/174,110 filed Oct. 17, 1998 now U.S. Pat. No. 6,341,393, which is a continuation in part of U.S. application Ser. No. 09/057,139 filed Apr. 8, 1998 now U.S. Pat. No 6,378,148, which is a continuation in part of U.S. application Ser. No. 08/713,412 filed Sep. 13, 1996 now U.S. Pat. No. 5,890,238, which is a continuation in part of U.S. application Ser. No. 08/527,519 now U.S. Pat. No. 5,737,781 filed Sep. 13, 1995. Additionally, this application is a continuation in part of U.S. application Ser. No. 09/545,538 filed Apr. 7, 2000, which is a continuation in part of U.S. application Ser. No. 09/174,110 filed Oct. 17, 1998, which is a continuation in part of U.S. application Ser. No. 09/057,139 filed Apr. 8, 1998, which is a continuation in part of U.S. application Ser. No. 08/713,412 filed Sep. 13, 1996, now U.S. Pat. No. 5,890,238, which is a continuation in part of U.S. application Ser. No. 08/527,519 now U.S. Pat. No. 5,737,781 filed Sep. 13, 1995. Furthermore, this application incorporates by reference the entire contents of the previously mentioned applications and patents and also the entire contents of U.S. Provisional Application No. 60/204,613 filed May 16, 2000. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to portable devices and their methods of use, which assist in moving patients positioned on beds, gurneys, or other such patient supports. More particularly, the invention relates to portable devices and their methods of use, which enable a single health care worker to perform a patient pullup, roll the patient to a desired position, reposition the patient, or laterally transfer the patient to another patient support. 
     2. Background of the Invention 
     Partially or totally incapacitated persons in hospitals, nursing homes, or other assisted care settings must often be periodically and routinely pulled up from a slumped position, rolled over, or transferred between patient supports such as beds and gurneys. Two or more attendants typically do these maneuvers manually; although the number of attendants required to perform a maneuver increases with the size and weight of the patient. 
     It is often desirable for patients to lie on platforms in which the head portion of the platform has been raised or angled upwardly. Often, to obtain the most benefit and comfort from a bed in this raised position, the patient should be disposed such that the patient&#39;s abdomen and thorax are in an elevated position. However, totally or partially incapacitated patients tend to slide or slump out of this position toward the foot of the bed, thereby losing the healthful benefits of a more upright position. 
     Another activity frequently required of caregivers is patient rollover. Patient rollover is necessary for maintaining patient comfort, facilitating examination, and preventing bed sores from forming. 
     A third activity is transporting the patient between patient supports, such as a bed to a gurney or cart, a cart to an operating or procedural table, etc. Generally speaking, this includes maneuvering the patient to another location. 
     Another activity is that of transporting beds containing bedridden patients. A large patient and a bed can weigh over 400 pounds. The transport of such a weight by pushing can place a severe strain on the attendant as well as creating a control problem. A heavily loaded bed, once in motion, can be difficult to stop. 
     Typically, space is limited in hospital and assisted care rooms. Therefore, devices to effect patient pullups, rollovers, or transfers must either occupy a minimum amount of space (if kept in the room) or be transported in and out of the room when required. Activities, such as pullups, are typically performed at frequent intervals and it is usually not feasible to transport equipment to and from a room to perform a patient pullup every two hours. However, if such a device used for pullup is to be stored in one of these rooms, the device must occupy a minimum of the limited space available and should be placed so that the pullup will be efficiently accomplished. 
     U.S. Pat. No. 2,827,642, issued to Huff on Mar. 25, 1958, discloses a device for moving a patient on a bed. The device includes a shaft mounted in ball bearing brackets. The brackets are bolted or otherwise secured to the headposts of the bed. Straps for a fabric webbing are secured to the shaft and a fabric supporting section is secured to the straps. A crank handle is removably secured to one end of the shaft. A patient lying on the fabric supporting section is pulled toward the head of the bed by cranking, and thereby winding the straps on the shaft. 
     U.S. Pat. No. 5,608,929, issued to Crane on Mar. 11, 1997, discloses a patient-positioning device. The positioning device includes a sheet which is placed under the patient and connected to a rope or braided line. One end of the braided line is anchored to a metal peg on the headboard. The remainder of the braided line is threaded through several pulleys. One of the pulleys is attached to a frame assembly. The patient is pulled up when the head portion of the bed is raised or by an independent motor operating to wind the line. The patient-positioning device of Crane, appears to require extensive retrofitting of beds and is not apparently transportable or suitable for various maneuvers. 
     U.S. Pat. No. 3,597,774, issued to Warren on Aug. 10, 1971, discloses a patient moving device which is attached to hospital beds. The patient moving device includes an adjustable post and clamps for attaching the post to the head of a bed. A winch is mounted on the post. A patient to be pulled up is secured with apron straps and apron tabs are connected to a T-bar. The T-bar is connected to a cable. The winch is operated to wind the cable and pull the patient up. Alternatively, a harness is employed. The harness is arranged under the patient&#39;s arm pits and connected to the T-bar before the winch is operated to pull the patient up. 
     U.S. Pat. No. 3,302,219, issued to Harris on Feb. 7, 1967, discloses a hospital bed and lifting and turning device. The lifting and turning device includes four vertical support members adjacent the head and foot of the bed. The vertical support members are hollow and threaded to receive the lower end of threaded members extending vertically from the vertical support members. The vertical support members are interconnected by side braces and transverse braces. A sprocket member is disposed atop each vertical member. Each sprocket member is adapted to threadably engage, and thereby raise or lower, a threaded member within the vertical support member. The drive sprockets are interconnected by an endless sprocket chain. An electric motor may be secured to one of the vertical members to drive the sprockets. Upper ends of the threaded members are provided with clamp members. Two elongated rods extend through outwardly extending portions of the clamp members. A sprocket wheel is secured to each elongated rod and separate sprocket drive chains connect sprocket wheel pairs at head and foot portions of the device. A fabric such as canvas is secured to the rods and rolled thereon. The fabric is rolled such that it will be wound on one rod and unwound from the other when the sprocket wheels are rotated. The hospital bed lifting and turning device of Harris appears to require extensive set up, is not readily transportable, and cannot effect a patient pullup or lateral transfer. 
     U.S. Pat. No. 5,544,371, issued to Fuller on Aug. 13, 1996, discloses a bed patient turning, lifting and transporting apparatus with a mobile, folding and knock-down frame. The apparatus does appear to be conveniently mobile and requires extensive set up before being used. The apparatus of Fuller also requires significant overhead space and could interfere or impede other necessary activities performed by medical personnel in attendance. 
     U.S. Pat. No. 5,659,905, issued to Palmer et al. on Aug. 26, 1997, discloses a patient transfer/turning bed. The patient transfer/turning bed of Palmer et al. includes powered rotating drive rollers on each side of the bed&#39;s mattress. The drive rollers are connected to articulating arms which pivot about an axis near the center of the head end and the foot end of the bed. A transfer/turning sheet removably connects the drive rollers. By raising the drive roller on one side of the bed, a patient will be rolled over toward the opposite side. The patient may also be transferred laterally across the bed by turning the drive rollers. In addition to requiring extensive bed retrofit, the patient transfer/turning bed of Palmer et al., is not readily transportable and cannot effect a patient pullup. 
     U.S. Pat. No. 2,665,432 issued to Butler on Jan. 12, 1954, discloses a patient transferring device. The patient transferring device of Butler is disclosed as including a roller mounted to a gurney. A pull unit is attached to the roller by a series of hooks and attaches to a transfer sheet. Although capable of effecting a type of lateral patient transfer, the patient transferring device of Butler cannot effect either a patient pullup or patient rollover. 
     U.S. Pat. No. 2,733,452, issued to Tanney on Feb. 7, 1956, discloses a hospital patient transfer device. The patient transfer device of Tanney is adapted to be mounted on a wheeled stretcher so that a patient may be transferred from a hospital bed to the stretcher or from the stretcher to the bed. The patient transfer device includes one roller mounted on the bed and another roller mounted on the stretcher. A cable is wound on one of the rollers and tracks thereby pulling a sheet from the stretcher while the sheet is guided beneath a patient disposed on the bed. After the patient and sheet are positioned, the sheet is wound on the roller mounted on the stretcher, thereby transferring the patient. The hospital patient transfer device of Tanney appears to require extensive bed and stretcher retrofit and cannot function either to pull a patient up or effect a patient rollover. 
     U.S. Pat. No. 4,776,047 issued to DiMatteo on Oct. 11, 1988, discloses a multiple function invalid bed arrangement for transferring a prone patient longitudinally or laterally between beds or surfaces adapted to accept the patient in a prone position. The longitudinal bed transfer is accomplished by equipping the patient&#39;s bed with two rollers, one roller at the head and one roller at the foot of the bed. A bed sheet is connected from the head to the foot roller much like a piano roll. The rollers are rotated to transfer the patient to a second bed which is equipped similarly. Thus, the multiple function invalid bed arrangement of DiMatteo appears to require extensive bed retrofit and cannot effect patient maneuvering without such retrofitting. 
     U.S. Pat. No. 4,868,938 issued to Knouse on Sep. 16, 1989, discloses a transportable patient mover and moving method. The patient mover moves a patient laterally from a first to a second surface such as from a bed to a gurney. The patient mover includes a bottom stand member and an upstanding support frame carrying an elongated roller. The support frame may be mounted on wheels or casters. One edge of a web-like sheet material is attached to the roller. The other edge of the web material is attached to a clamp. A transfer sheet disposed beneath a patient is secured by the clamp and the roller winds the web thereon, thereby transferring the sheet and patient thereon. The patient mover of Knouse does not appear suitable for remaining in a small hospital room between uses without interfering with essential activities. 
     There is a need for a portable device, which can enable a single attendant to effect patient pullups, rollovers, and lateral transfers, which is readily transportable, and which may be conveniently stored in a patient&#39;s room between uses. Further there is a need for a device that will allow a single attendant to relocate beds containing bedridden patients without transferring them out of the bed. 
     SUMMARY OF THE INVENTION 
     This invention meets the needs of the industry by providing a portable device for maneuvering a patient who is located on a support platform. The support platform may be configurable to a generally horizontal position or otherwise. A pliable underlayment designed for use with the portable patient transfer device may be disposed between the patient and the support. The device is operable by a single person or operator and may include a housing, a motor winch assembly at least partially disposed within said housing, one or more strap and hook assemblies comprising transfer straps and transfer hooks and at least one mating assembly. Furthermore, some embodiments of the invention are capable of transporting a patient on a patient support under the control of an attendant. 
     The strap and hook assemblies may be windably attachable to the motor winch assembly and comprises transfer straps operably connected to the transfer hooks. The mating assembly may be in electrical communication with the motor winch assembly and/or may include a mechanism for stabilizing the device. The stabilizing mechanism may be actuated by contacting a first member of the patient support and may also be in electrical communication with an internal or external power source. It is noted that the power source may be internal to the patient support thereby providing power to the transfer device when plugged into the patient support. The stabilizing mechanism may also include a locking mechanism accommodated by the support. 
     The strap and hook assemblies may include at least one strap and at least one hook. Generally, each strap may be attachable to the motor winch assembly and to one or more of the hooks. The device may further include a first base member and an optional second base member. The second base member may be locked into an extended position to further stabilize the device. 
     This invention also provides a method of displacing a patient. The method includes providing a device with a housing, a motor winch assembly at least partially disposed within said housing, transfer straps windably adjoined to the motor winch assembly, transfer hooks secured to the straps, and at least one mating assembly. The strap and hook assembly may be attachable to the motor winch assembly. The mating assembly may be in electrical communication with the power train and/or may include means for stabilizing the device. Next, the method includes stabilizing the device by contacting a first member of the support to the stabilizing means. The stabilizing mechanism may be actuated by contact with a first member of the support and may be placed in electrical communication with a power source when contacted with the first member of the support. Once the device is stabilized and powered, the method generally includes securing a pliable underlayment, proximate to the patient, to the strap and hook assembly. The securing of the underlayment prepares the operator to activate the device and transfer or reposition the patient by allowing the device to pull the underlayment and patient to a desired position. 
     The present invention encompasses several different embodiments. A first embodiment includes a modular, portable patient relocation device. The modular, portable patent relocation device includes engagement members adapted to be engaged to a patient support such as a hospital bed, gurney, cart or any other patient support. Another embodiment of the invention is particularly adapted to engage the headboard, side rails and/or footboard of a hospital bed and may include connectors to draw power from the hospital bed power supply. Yet another embodiment of the invention is configured to replace the existing hospital bed headboard, side rails and/or footboard and may be configured to draw its power supply directly from the hospital bed. A further embodiment of the invention is configured to be temporarily or permanently secured to a hospital bed frame with the pulling members routed via a series of pulleys to allow pulling from the vicinity of the hospital bed headboard, side rails and/or footboard. Yet another embodiment of the invention may further include a drive train connectable to the wheels of the hospital bed to allow for power transport of the hospital be as a whole. Yet another embodiment of the invention may include retractable upright members whereby the pulling members may be directed over the sides of the hospital bed for use in rolling over hospital patients. 
     A further embodiment of the invention includes a stabilizing base and rolling assembling by which the patient relocation unit may be transported on wheels making it unnecessary to carry the invention. In a variant on this embodiment of the invention, the wheel base and column may include connections to engage the electrical supply of a hospital bed to power the patient relocation unit. The column in a further embodiment of the invention may include the ability to adjust the height of the patient transfer device. The rolling transfer device may also include a clamping device for mechanically engaging the base of a hospital bed to improve stability or to allow the patient relocation device to be used as a tug to provide power to relocate the entire hospital bed along with patient. 
     A final embodiment of the invention may include a clamping device for engaging the base of a hospital bed that also lifts the hospital bed from the ground to allow transportation to a remote location. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an elevational view of the first embodiment of the portable patient transfer device as transported by an operator along with a patient support; 
     FIG. 2 is a perspective view of the portable patient transfer device of the present invention; 
     FIG. 3 depicts a second embodiment of a portable patient transfer device; 
     FIG. 4 is an additional perspective view of the second embodiment of the portable patient transfer device; 
     FIG. 5 depicts another embodiment of the patient transfer device adapted for replacing an existing hospital bed headboard; 
     FIG. 6 is a perspective view of another embodiment of the patient transfer device; 
     FIG. 7 is a side-elevational view of the patient transfer device of the present invention; 
     FIG. 8 is a perspective view of the patient transfer device of the present invention further depicting a shroud; 
     FIG. 9 is a perspective sectional view of another embodiment of the patient transfer device of the present invention; 
     FIG. 10 is a detail perspective view of a patient transfer device of the present invention; 
     FIG. 11 is a perspective sectional view of a patient transfer device embodiment that includes a drive mechanism; 
     FIG. 12 is a perspective view of another embodiment of patient transfer device including foldable rollover members in the operating position; 
     FIG. 13 is a perspective view of the folding rollover members in a storage position; 
     FIG. 14 is a perspective view of an embodiment of a rolling patient transfer device of the present invention; 
     FIG. 15 is a front and side elevation view of the patient transfer device of FIG. 14; 
     FIG. 16 is a perspective view of another embodiment of the patient transfer device; 
     FIGS. 17A &amp; B are front and side elevational views of the patient transfer device of FIG. 16; 
     FIGS. 18A-C are side elevational views of the patient transfer device of FIGS. 17A &amp; B in operation; 
     FIG. 18D is a perspective view of an embodiment of a rolling transfer device wherein the handle is operably connected to a wheel; 
     FIGS. 19A &amp; B are side elevational views of another embodiment of the patient transfer device of the present invention that includes a clamping mechanism; 
     FIG. 20 is a detailed perspective view of a clamping mechanism as used with a patient transfer device of the present invention; 
     FIG. 21 is a perspective view of patient transfer device of FIGS. 19A &amp; B and  20  in operation; 
     FIG. 22 is a rear view of an embodiment of a rolling transfer device with the rear panel removed; 
     FIG. 23 is a view of an embodiment of a patient transfer device with the upper housing removed; 
     FIG. 24 is another view of an embodiment of a patient transfer device with the upper housing removed; 
     FIG. 25 is a perspective view of an embodiment of a patient transfer device with the upper housing removed; 
     FIG. 26 is an exploded view of one embodiment of a magnetic clutch assembly, slip plate, and drum assembly present in the embodiment of FIG. 22; 
     FIG. 27 is a perspective view of a web attached to the drum assembly of the embodiment of FIG. 22; 
     FIG. 28 is a plan view of the web and drum assembly of FIG. 27; 
     FIG. 29A is an exploded view of the strap of FIG. 27 and a transfer hook assembly; 
     FIG. 29B is a side view of the transfer hook of FIG. 29A; 
     FIG. 30 is another embodiment of the transfer system of the present invention, whereby a patient may be bidirectionally transferred without the necessity of reinstalling this embodiment on another bed or cart; 
     FIG. 31A is a side plan view of the embodiment of FIG. 30, wherein a patient is being transferred away from the bed on which the embodiment is installed; 
     FIG. 31B is a side plan view of the embodiment of FIG. 30, wherein a patient is being transferred onto the bed or cart onto which the embodiment is installed; 
     FIG. 32 is a perspective view of an embodiment of a transfer bar; 
     FIG. 33 is a top plan view of a transfer bar that includes slots offset from center; 
     FIG. 34 is a top plan view of a first embodiment of a transfer sheet cooperating with a plurality of attaching members to form pockets; 
     FIG. 35 is a top plan view of a second embodiment of the sheet of FIG. 34; 
     FIG. 36 is a top plan view of a third embodiment of the sheet of FIG. 34; 
     FIG. 37 is a fragmentary perspective view of the sheet of FIG. 34 with a repositioning bar being inserted therein; 
     FIG. 38 is a fragmentary perspective view of the sheet of FIG. 34 with a repositioning bar in place; 
     FIG. 39 is fragmentary perspective view of the sheet of FIG. 34 with a repositioning bar inserted and with a transfer hook being attached thereto; 
     FIG. 40 is a fragmentary perspective view of an embodiment of another sheet of this invention; 
     FIG. 41 is a perspective view of the sheet of FIG.  40 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIGS. 1 and 2 depict a first embodiment of a patient transfer device  30 . Patient transfer device  30  generally includes housing  32 , handle  34  and a mating assembly  35 . In FIGS. 1 and 2 the mating assembly  35  includes a first mating member  36  and second mating member  38 . However, the mating assembly  35  may comprise any number of mating members that would operably adjoin the patient transfer device to a patient support. Housing  32  encloses motor winch assembly  40 . Generally, the motor winch assembly  40  is operably connected to one or more hook and strap assemblies (not shown) that may be adjoined to a pliable transfer sheet (not shown), which functions to transfer or reposition a patient. It is noted that a description of the hook and strap assemblies and the transfer sheet will be described later in this disclosure. 
     In various embodiments of the present invention, a motor winch assembly  40  includes a motor  41 , one or more reduction drive  43 , one or more drums  45  and one or more strap and hook assemblies  47 . The motor  41  is preferably an electric motor but may include hydraulic or pneumatic motors. Reduction drives  43  are operably connected to the motor  41  and preferably reduce the motor speed sufficiently to allow for a patient transfer to be accomplished within a short period of time, i.e. twenty to thirty seconds. The drums  45  are operably connected to the reduction drives  43  and are adapted to windably receive the strap and hook assemblies  47 . The strap and hook assemblies  47  preferably include high strength synthetic webbing similar to that used in automobile seat belts but, may also include cables, cords or any other elongate material of appropriate strength and flexibility. The clamping portion (not shown) may be any type of connector that may be readily and securely releasably-attached to a pliable transfer sheet as describe later in this disclosure. Furthermore, suitable motor winch assemblies  40 , as well as retracting and transfer devices, such as strap and hook assemblies and pliable transfer sheets or drawsheets, for transferring and repositioning a patient, are disclosed in U.S. Pat. Nos. 5,737,781; 5,890,238; and U.S. patent application Ser. Nos. 09/057,139 and 09/307,637 which are hereby incorporated in their entirety by reference. 
     Patient transfer device  30  may be used in combination with a bracket  42  and a platform  44 , which are secured to a patient support  46 . The patient support  46  may comprise a hospital bed, gurney, operating table, or any other platform upon which a patient may be supported in a hospital or nursing home setting. The bracket  42  further includes first slot  48  and second slot  50 . First slot  48  and second slot  50  may further include securing devices  52 . Securing devices  52  are configured to engage to first mating member  36  and second mating member  38  to securely hold patient transfer device  30  to bracket  42 . Securing devices  52  may include pins, latches, clamps, or any other mechanism or device by which first and second mating members  36 ,  38  may be securely, removably held in first slot  48  and second slot  50 . It is noted that the bracket  42  may comprise other configurations that can adequately accommodate and secure the patient transfer device to the patient support  46 . 
     Patient transfer device  30  further includes power supply  54 . Power supply  54  may be self-contained in the form of an internal power pack, such as batteries, or may be drawn from an outside source by a simple power cord operably attached to an electrical outlet, or by one or more power connection ports  56  incorporated into the mating assembly  35 . The incorporation of one or more power connection ports  56  to the mating assembly  35  may allow for the patient transfer device  30  to be powered by a power supply operating through the patient support  42 . 
     FIGS. 3 and 4 depict a second embodiment of the patient transfer device  58 . Patient transfer device  58  is adapted to be secured to bed headboard  60 . Patient transfer device  58  generally includes housing  62 , mating assembly  64 , and motor winch assembly  40  as previously described. In this embodiment, the motor winch assembly  40  is operably connected to one or more strap and hook assemblies  47 . In many of the embodiments the strap and hook assemblies  47  include a strap  67  operably attached to one or more clamping devices  69 . 
     In the embodiments depicted in FIGS. 3 and 4, the mating assembly  64  includes one or more mating members  65  that may be operably adjoined to the headboard  60 . The headboard  60  is robustly constructed to support the weight of patients being transported. Also, the headboard  60  generally includes one or more mating ports  66  and one or more power connection port  68  that are both configured for receiving the mating members  65 . It is noted that the mating ports  66  and power connection port  68  may be consolidated. Additionally, the motor winch assembly  40  may draw its power supply through the one or more power connection ports  68 . Power connection port  68  may draw power from an existing electrical supply  70  present within or operably connected to the patient support  72 . 
     FIG. 5 depicts another embodiment of the present invention of the patient transfer device  30 , wherein the patient transfer device  30  is a retrofitted modular headboard  74 . The retrofitted modular headboard  74  is configured to replace the headboard  76  of a conventional hospital bed  78 . The modular headboard  74  includes housing  32 , motor winch assembly (not shown), transfer straps  80 , transfer clamps  81  such as hooks, and a control panel  82 . The motor winch assembly, transfer straps  80 , transfer clamps  81  and control panel  82  are similar in all embodiments of the invention herein disclosed. The control panel  82  may include automated touch sensitive activators  83 , such as buttons or knobs that perform various functions upon activation, such as release or retraction actions. 
     FIGS. 6-8 depict an additional embodiment of the retrofitted modular transfer device  74 . One embodiment of the modular transfer device depicted in FIGS. 6-8 includes a housing  32 , motor winch assembly (not shown), transfer straps  80 , control panel  82  and optionally, one or more strap positioning devices  84 . The strap positioning devices  84  are secured to mattress support  88  and assist in redirecting the route of the transfer straps  80 . The housing  32  encloses the motor winch assembly and may include transfer pulleys  85 . Additionally, the housing  32  may define a plurality of housing slots  87 . A control panel  82  that includes automated activators  83  is also accommodated by the housing  32 . The housing  32  may be dimensioned and configured to fit any of several standard hospital beds, gurneys or any other patient support  46  and may be configured to replace a modular headboard fixture  79  that does not include the operating patient transfer device components. 
     The strap positioning devices  84  house one or more positioning pulleys  86  and defines a plurality of positioning slots  89 . The strap positioning devices  84  may be configured to be affixed to mattress frames of any standard hospital bed, gurney or any other patient support  46 . Transfer pulleys  85 , housing slots  87 , positioning pulleys  86 , and positioning slots  89  constitute a plurality of paths, each path guiding a strap  80  as depicted in FIGS. 7 and 8. The straps  80  are attached to a clamping device  90  that is adapted for securing a pliable transfer sheet  91 . Suitable embodiments for strap  80  and clamping devices  90  are disclosed in the above-incorporated U.S. Patents and U.S. Patent Applications. 
     In various embodiments of the present invention, the housing  32  is dimensioned to replace the headboard, footboard or side rails of hospital beds, gurneys or other types of patient supports. FIGS. 6A-B depict two embodiments of a modular transfer device  74  that may be utilized to replace a modular headboard fixture  79  of a hospital bed or other patient support. The modular headboard fixture  79  may be a hollow housing or a solid structure, which include inserts  77  shaped to conform and fit with the mating assembly  35 . As depicted in FIG. 6B, the modular headboard fixture  79  may be removed from the patient support  72  and the modular transfer device  74  may be positioned in its place. The modular transfer device may include electrical communication devices  75  that may channel power to the modular transfer device  74  through or from the patient support  72  when adjoined to the patient support  72 . 
     Additionally, as can be seen in FIG. 8, patients may be repositioned using modular patient transfer device  74  when the hospital bed is in any number of positions. Moreover, when straps  80  are attached to a transfer sheet  91  upon which a patient is disposed, the patient may often be repositioned simply by raising the head portion of the mattress to an elevated position. 
     Referring to FIGS. 9 and 10, a further embodiment of the invention is depicted. In this embodiment, patient transfer device  30  is located beneath bed frame  92  and generally includes housing  32 , motor winch assembly  40 , transfer straps  80 , and positioning pulleys  86 . In the present embodiment, the patient transfer device  30  is secured under the bed frame  92 . The straps  80  extend around the positioning pulleys  86  and are secured to the transfer sheet  91 . Pulleys  86  may be adjoined to the surface of the headboard  93  or positioned within the headboard  93  to facilitate the movement of the patient in a desired direction. 
     Referring to FIG. 11, patient transfer device  90  may optionally include a mechanism to mechanically move the patient support  46 . The patient transfer device  90  of FIG. 11 includes a motor device  94  operably adjoined to a drive shaft  95 . The drive shaft  95  extends to a gear box  96  that is operably connected to an axle  98  that provides a driving force to one or more drive wheels  100 . Drive shaft  95  may optionally include drive chains, belts or any other appropriate drive mechanism. Additionally, gear box  96  may advantageously be a differential. Also, this embodiment of the present invention further may include a control panel  102  for activating and controlling the movement of the patient support  46 . 
     Another embodiment of the present invention is a patient transfer device  90  that includes retractable rollover members  104 . FIGS. 12 and 13 depict retractable rollover members  104  that are advantageously secured to bed rails  106 . The retractable rollover members  104  may be folded to a storage position  108  or folded to an operating position  110 . The retractable rollover members may also be stored by other means such as telescoping downward towards the patient support  46 . The retractable rollover members  104  include pulleys (not shown) that guide and facilitate the movement of the transfer straps  80  up the retractable rollover member and across the patient for securement to the transfer sheet  93 . 
     FIGS. 14-21 depict a rolling patient transfer device  112 . Rolling transfer device  112  generally includes housing  114 , motor winch assembly  116 , power assembly  111 , column  118 , and rolling base assembly  120 . The column  118  may include a mating assembly  119  having connectors  122  that comprise electrical connectors  124 , mechanical connectors  126  or both. Mechanical connectors  124  include but are not limited to clamps, hooks, magnets and other similar devices. An example of a mechanical connector  124  includes the clamping mechanism depicted in FIGS. 19 and 20. Furthermore, the column  118  may also optionally include a handle  128 . 
     As previously mentioned, embodiments of the rolling transfer device  112  include a rolling base assembly  112  comprising a platform  130  adjoined to wheels or casters  132 . The wheels  132  may be free rolling or powered. The column  118  may be adapted to secure to the platform  130  or may have portions thereof incorporated into the platform resulting in a unitary piece. 
     Referring particularly to FIGS. 16 and 17A and B, column  118  may include inner column  134  and outer column  136 . Inner column  134  is slidably received within outer column  136  in a telescoping fashion such that housing  114  may be vertically adjustable. In one embodiment vertical adjustment of the patient transfer device  112  may be accomplished by movement of a handle  128  operably connected to the rolling transfer device  112 . 
     Referring particularly to FIG. 18A-C, handle  128  may be adapted to operate an elevating mechanism  138 . The elevating mechanism  138  may include hydraulics, a screw or scissors jack or any other appropriate mechanism known to the art. Additionally, the handle  128  may also be utilized to maneuver the rolling transfer device  112 . FIG. 18D depicts an embodiment of the rolling transfer device  112  wherein the handle  128  is operably connected to a wheel or castor  129 . The embodiment depicted in FIG. 18D provides the operator the ability to easily maneuver and direct the rolling transfer device  112  in the desired location by simply manipulating the handle  128 . Also the handle is adapted to fold upward to a position proximate to the housing  114  of the rolling transfer device  112 , thereby allowing for placement of the device  112  in tight locations, i.e. between patient supports and walls. It is noted that the rolling transfer device  112  depicted in FIG. 18D may also include the features described above for adjusting height. 
     The connectors  122  are matable to bed frame connectors  140  as shown in FIG.  16 . Bed frame connectors  140  may include one or more mechanical interfaces  142 , one or more electrical interfaces  144  or both. Mechanical interfaces  142  may be releasable connectable to bed frame connectors  140 . Electrical interface  144  may be configured to draw electrical power to operate motor winch assembly  40 , to charge power supply  54  if self contained and to provide power wheels  132  if powered. 
     Referring particularly to FIGS. 19A and B,  20 , and  21 , either column  118  or rolling base assembly  120  may further include a mating assembly  119  in the form of one or more clamping mechanisms  146 . In one embodiment of the present invention, the clamping mechanisms  146  includes a fixed member  148  and clamping member  150 . The clamping member  150  is movably operable to engage patient support member  152  and may lock into position upon engagement with the patient support member  152 . Additionally, the clamping member  150  may be actuated or released by foot pedal  154  or any convenient actuating mechanism, such as a button, lever, knob or other similar device. The clamping member  150  actuation or release may be electrical, hydraulic or mechanical in nature. 
     FIGS. 22-25 depict one embodiment of the motor winch assembly  116  that may be utilized in the patient transfer devices  30  of the present invention. The motor winch assembly  116  includes motor  340 , motor shaft  342 , first bevel gear  344 , second bevel gear  346 , axle shaft  348 , a plurality of magnetic clutch assemblies  350 , a plurality of slip plates  352 , and a plurality of drum assemblies  354 . Motor  340  is mounted generally vertically proximate a lower surface of plate  270  by means of fasteners such as machine screws or bolts. Motor shaft  342  extends from motor  340  through plate  270 . Respective first and second bevel gears  344  and  346  are affixed to motor shaft  342  and axle  348 . Suitable exemplary magnetic clutch assemblies  350 , motor  340 , slip plate assemblies  352 , and drum assemblies  354  are depicted and cooperate with axle  348  in a manner substantially similar to that depicted and described in above-referenced U.S. patent application Ser. No. 09/057,139 and U.S. patent application Ser. No. 09/174,110. 
     One embodiment of a motor  340  is a permanent magnet, parallel shaft, DC brush gear motor, operating at 12 volts DC and generating approximately ⅛ hp. In this embodiment, motor  340  rotates motor shaft  342  at an output speed of between about 25 rpm and 75 rpm and attains an output torque range of between approximately 300 in-lbs at 25 rpm and 100 in-lbs at 75 rpm. An exemplary motor may be obtained from Byson Gear and Engineering Corporation, Downers Grove, Ill. However, it is noted that other types of motors known to those skilled in the art may be utilized with the transfer device of the present invention. 
     As seen in FIG. 26, each magnetic clutch assembly  350  includes disk  360  and cylindrical housing  362 . A generally coaxial bore  364  extends through magnetic clutch assembly  350 . In this embodiment, bore  364  has a diameter of about ½ inch to accommodate axle  348  and disk  360  has a diameter of approximately 4.9″ (±0.5″). Cylindrical housing  362  has a diameter of approximately 4.2″ (±0.5″) and a depth of approximately 1.8″ (±0.5″). An exemplary magnetic clutch develops a torque of 22 lb-ft, and attains a coil power of 28 watts, an armature hub inertia of 161×10 −4  lb-ft 2 , a rotor inertia of about 172×10 −4  lb-ft 2 , and generates 3 hp at 1800 rpm. Disk  360  may be mounted to outboard surfaces of vertical elements  250  and  252  by fasteners such as screws or bolts. Magnetic clutch assembly  350  is mounted such that axle  348  extends generally coaxially through bore  364 . Axle  348  and magnetic clutch  350  may be affixed by a keyway combination (not shown). Each slip plate  352  defines bore  368 , a plurality of peripheral holes  370 , and presents an inboard surface  372 . Magnetic clutch assembly  350  and slip plate  352  are designed to perform a patient displacement so as to provide maximum comfort to the patient. In one embodiment, when magnetic clutch assembly  350  and slip plate  352  are actuated, a gradual acceleration to, and deceleration from, normal operating speed occurs rather than immediate commencement or cessation of normal operating speed, each of which would otherwise result in an abrupt jerk. In yet another embodiment, magnetic clutch assembly  352  and slip plate  352  remain engaged when axle  348  rotation ceases, thereby preventing the web from unwinding from drum assembly  354  until magnetic clutch assembly  350  and slip plate  352  are disengaged. 
     Each exemplary drum assembly  354  includes cylindrical member  376 . Four threaded extensions  378  may extend peripherally from cylindrical member  376  and disk  380  may be unitarily joined to cylindrical member  376 . Disk  380  presents an outboard surface and defines a threaded aperture. Cylindrical (spool) member  384  coaxially extends from the outboard surface of disk  380 . Outboard disk  385  extends generally coaxially and radially from cylindrical member  384 . Outboard disk  385  defines aperture  386  and presents an outboard surface. Aperture  386  is generally aligned with the threaded aperture defined in disk  380  in this embodiment. 
     Also in this embodiment, a fastener such as a screw extends through each aperture  370  and is threadably disposed within each threaded extension  378 . Screw  390  is extended through aperture  386  and is threadably received within the threaded aperture defined in disk  380 . Bores are coaxially formed within slip plate  352  and drum assembly  354 , respectively, such that axle  348  may be received there within. Drag cap spring  392  is compressibly held in place by drag cap  394 . Drag cap  394  cooperates with a fastener such as screw  396  threadably received within an aperture proximate each terminus of axle  348 . In this embodiment, power train  106  is dimensioned such that cylindrical members  384  may be spaced between about 18 inches and 22 inches, between about 19 inches and 21 inches, or about 20 inches, on center. 
     FIGS.  25  and  27 - 29  depict one embodiment of the strap and hook assembly  47  and the components utilized in this embodiment. The strap and hook assembly  47  may include transfer strap  402 , transfer hook assembly  404 , stop  406 , and an exemplary transfer rod embodiment. However, it is contemplated that other means of securing pliable underlayments such as transfer sheets may be used with this invention. Suitable securing means include various clamps and/or tethers disclosed in above-referenced U.S. Pat. No. 5,737,781. This invention is also contemplated to include securing means disclosed in above-referenced U.S. Provisional Application No. 60/084,519 and U.S. Provisional Application No. 60/092,286. With the exception of stop  406 , exemplary strap and hook assembly  47  may be substantially equivalent to that disclosed in above-referenced U.S. patent application Ser. No. 09/057,139 and U.S. patent application Ser. No. 09/174,110. Loops similar to loop  414  are formed at each end of strap  402 . Loops  414  are formed by such means known to the art as stitching  416  or gluing (not shown). 
     One embodiment of the transfer hook assembly  404  includes transfer hook  420 , joint connector  422 , and joint connecting bolt  424 . Exemplary transfer hook  420  is unitary, but may be envisioned as including strap retaining member  426  and hook member  428 . Strap retaining member  426  displays exterior surface  429  and defines bore  430  and slot  432 . Flange  434  extends from strap retaining member  426 . Hook member  428  and strap retaining member  426  cooperate to define gap  436  therebetween. Strap  402  is attached to transfer hook  420  by inserting joint connector  422  within loop  414  and disposing loop  414  and inserted joint connector  422  in bore  430  such that web  402  extends through gap  432 . Joint connector  422  is then secured within bore  430  by threading joint connector bolt  424  in joint connector  422 . Web  402  is attached to drum assembly  354  by aligning loop  412  with aperture  386  and the aperture defined in disk  380 , then inserting screw  390  through aperture  386  and loop  412  and subsequently threading screw  390  into the aperture defined in disk  380 . Dimensions and materials used in one embodiment of transfer hook assembly  404  may be found in above-referenced U.S. patent application Ser. No. 09/057,139 and U.S. patent application Ser. No. 09/174,110. In one embodiment, strap  402  is nylon webbing 1½ inch in width and 73¾ inches in length, but is 70 inches in length after loops  412  and  414  are formed. 
     Referring to FIGS. 22-24, the power system  111  includes power supply assembly  500  that is operably connected to circuit board  502 , control panel (not shown) and motor  340 . Power supply assembly  500 , in turn, includes power supply cord  510  and rectifier  512 . The power supply cord may be adjoined to an exterior power source or may be operably connected to electrical connectors  124  that may be received by electrical interfaces (as shown in FIGS. 14 and 15) adjoined to the patient support  46 . Rectifier  512  converts commonly available AC, 60 Hz, 115 V current to DC, 12 V required by motor  340 . However, other rectifiers converting other forms of alternating current are contemplated to be within the scope of this invention. Furthermore, other power supply systems such as those depicted and described in above-referenced U.S. patent application Ser. No. 09/545,538, U.S. patent application Ser. No. 09/057,139 and U.S. patent application Ser. No. 09/174,110 are contemplated to be within the scope of this invention as well. 
     Patient transfer device  900 , as depicted in FIGS. 30 and 31A and B, broadly includes bed  902 , cart  904 , motor-winch unit  906 , perpendicular transfer units  908 ,  910 ,  912 , clamp  914  and a plurality of belts discussed below. Although depicted as cart  904 , a bed or other horizontal surface may be used and still be within the spirit and scope of the present invention. Motor-winch unit  906  may be attached to base  916  of bed  902 . Perpendicular transfer unit  908  is attached to the upper frame of bed  902 . Another perpendicular transfer unit  910  is attached to the upper frame on adjoining cart  904 . Still another perpendicular transfer unit  912  is attached to the lower frame of cart  904 . 
     As shown in FIG. 30, a pair of straps  918  may extend generally upwardly from motor-winch unit  906  through perpendicular transfer unit  908 , finally extending horizontally on mattress  915 . Straps  918  are then attached to clamp  914  in any manner such as described herein. Alternately, straps  918  may proceed horizontally from motor-winch unit  906 , beneath bed  902  and cart  904  and through perpendicular transfer unit  912 . Extending generally upwardly and vertically from perpendicular transfer until  912 , straps  918  pass through perpendicular transfer unit  910 , then onto mattress  917 . On mattress  917 , straps  918  may be attached to a clamp such as a clamp of the present invention. In one embodiment, motor-winch unit  906  may be attached to bed  902  by means of a mating assembly in the form of rings  922  extending from housing  920 . Rings  922  may enclose an upper portion of casters  924  on which bed  902  is mounted. It is also noted that the motor winch unit  906  may include electrical connectors (not shown) that plug into the bed  902 . The electrical connectors may be utilized to supply power to the unit  906  derived from a power source located within or channeling through the bed  902 . 
     The embodiments of the patient transfer device  30  may be utilized in conjunction with a transfer sheet  93  and a transfer bar  95 . FIGS. 31 and 32 depict embodiments of the transfer bar  95 . As previously suggested, the transfer bar  95  may be used in conjunction with transfer sheet  93 . The transfer bar  95  is a unitary member that may comprise a metal or plastic material. However, other embodiments of transfer bar  95  may comprise more than one member in construction. It is preferable to produce the transfer bar with a flexible plastic material to reduce or prevent injury to the patient when performing a patient reposition motion or transfer. Transfer bar  95  defines first and second ends  162 ,  164  and first and second bar slots  166 ,  168 . It is noted that other embodiments of the transfer bar  95  may include more than two bar slots. One embodiment of the transfer bar  95  is proportioned, and first and second bar slots  166 ,  168  are spaced apart, such that bar slots  166 ,  168  are exposed when transfer bar  95  is disposed in a pocket of the transfer sheet  91  (a description of one embodiment of the transfer sheet is described below). In one embodiment slots  166 ,  168  are spaced apart about 24 inches on center and transfer bar is about one inch wide, one-fourth inch in depth, and 26¾ inches in length. While bar slots  166 ,  168  are shown generally centered, as shown in FIG. 32, first and second bar slots  166 ,  168  may be offset as well, as shown in FIG.  33 . Offset bar slots tend to maintain transfer bar  95  in a flattened position during a patient transfer or pullup, thereby decreasing the likelihood of transfer bar  95  being bent. Bar slots  166 ,  168  are dimensioned to accommodate a transfer or repositioning hook such as transfer hook  81 . Sheet slots  2460  may also be formed proximate the pockets in the transfer sheet  91  and are also proportioned to accommodate connecting members such as transfer hook  81  (See FIG.  34 ). The transfer hook  81 , in this example, may extend through the sheet slot  2460  in the transfer sheet  91  and attach to transfer bar  95  disposed therein. 
     FIGS. 35-41 depict various embodiments of a transfer sheet that may be utilized in conjunction with the transfer device of the present invention. Transfer sheet  2450  displays respective first, second, third, and fourth edges  2484 ,  2486 ,  2488 ,  2490 . In FIG. 34, a plurality of pockets  2459  are depicted extending generally parallel to respective first, third, and fourth edges  2484 ,  2488 ,  2490 , corresponding to a patient&#39;s head and sides. FIG. 35 depicts a plurality of pockets  2459  extending generally parallel to respective third and fourth edges  2488 ,  2490 , corresponding to portions of transfer sheet  2450  normally flanking a patient. In FIG. 36 a plurality of pockets  2459  are depicted extending generally parallel to each respective first and second edge  2484 ,  2486 . Edges  2484 ,  2486 , respectively, correspond to edges proximate a patient&#39;s head and foot. While pockets  2459  are depicted as generally contiguous or adjoining in FIGS. 35-39, pockets  2459  may be spaced apart as well. 
     In FIGS. 40-41 other embodiments of the substantially pliable underlayment of this invention are depicted. Referring to FIGS. 40,  41 , the pliable underlayment of the present invention is depicted generally as transfer sheet  2560 . Transfer sheet  2560  includes mantle  2562  and a plurality of reinforced portions  2564 . A sheet slot  2566  is defined within each reinforced portion  2564  in this embodiment. Adjacent reinforced portions  2564  cooperate to form reinforced edges  2568 . In this embodiment slots  2566  are configured to accommodate a grasping or connecting member such as transfer hook  1552 . In this invention, any of slots  2506 ,  2526 ,  2566 , aperture  2546  or any opening formed in a pliable underlayment such as any of the transfer sheets described above, may be bordered by such protective and reinforcing means such as grommets. 
     In operation, referring particularly to FIGS. 1 and 2, portable patient transfer device  30  may be hand carried to the desired location of use by grasping handle  34 . The portable patient transfer device may then be secured to the patient support  46  by inserting first mating number  36  and second mating number  38  into first slot  48  and second slot  50 . The operator may then engage the securing devices  52 , if present, to hold the portable patient transfer device  30  in place. Once secured to the patient support, the strap and hook assemblies  47  are adjoined to the transfer sheet  91 . The transfer sheet  91  may be engaged with the strap and hook assemblies  47  by either placing one or more transfer clamps  81  into one bar slots  166 ,  168  or sheet slots  2566 . The patient transfer device  30  may then be activated to complete the patient repositioning or transfer. 
     Referring to FIGS. 3 and 4, patient transfer device  58  may be secured to the top of headboard  60  via mating members  64  and mating ports  66 . The positioning of the patient transfer device  58  on the top of the headboard  60  may optionally place the device  58  in communication with a power source operating through the patient support  46 . Once secured in place the patient transfer device  58  may be used to accomplish pull-ups by engaging the transfer sheet in a similar method to that previously described. 
     Referring now to FIG. 5, patient transfer device  74  may be substituted for headboard  76 . It is further noted that other embodiments similar to the patient transfer device  74 , as disclosed in FIG. 5, may include, but are not limited to transfer devices  30  adapted and configured to releasably replace footboards or side rails. Once in place, patient transfer device  74  may be operated via control panel  82  in order to accomplish pull ups, repositioning, rollovers or patient transfers in a method similar to that previously described. 
     Referring to FIGS. 6-10, when operating patient transfer device  74 , which includes one or more strap positioning devices  84  and pulleys  86 , the strap and hook assemblies  47  are threaded through pulleys  86  located in the strap positioning device  84 . Once threaded through the pulleys  86 , the strap and hook assemblies  47  are engaged with the transfer sheet  91 . Activation of the patient transfer device  74  then guides the straps  80  through or around the pulleys  86  thereby accomplishing the patient pull-up, reposition, rollover or transfer. 
     Referring to FIG. 11, this embodiment of the patient transfer device  90  further allows transportation of an entire patient support  46  with patient. In operation, the patient transfer device  90 , secured under the patient support  46 , activated by the operator to initiate the drive shaft  95 , which drives one or more of the wheels  100  on the patient support  46 . The operator may manipulate the patient transfer device  90  by using an automated control panel  102  that controls the speed and direction of the patient support  46 . 
     Referring to FIGS. 12 and 13, this embodiment of the patient transfer device  90  includes foldable roll over members  104 . When not in use, foldable roll over members  104  may be folded parallel to bed rails  106  or retracted into the storage position  108  as depicted in FIG.  13 . One embodiment of the rollover members  104  may include a telescoping member (not shown), which allows for the raising and retraction of the rollover members  104 . When it is desired to roll over a patient, foldable roll over members  104  may be lifted to an operating position  110 . Thereupon, transfer straps  80  may be engaged with the transfer sheet  91 , followed by the activation of the transfer device  90  to accomplish patient roll overs in an ergonomic fashion. 
     Referring to FIGS. 14-17A and B, rolling patient transfer device  112  may be transported to its location of use by pushing by an attendant if wheels  132  are free-rolling or under its own power in the case of power wheels  132 . Rolling patient transfer device  112  is aligned so as to engage connectors  122  to bed frame connectors  140 . Depending upon the embodiment of the invention, bed frame connectors  140  may also include electrical interface  144  to supply electrical power for the operation of motor winch assembly  40 . After engagement of the connectors  122  to the bed frame connectors  144 , the strap and hook assemblies  47  may be adjoined to the transfer sheet  91  for repositioning and/or transfer of the patient. 
     Referring to FIGS. 18A-D, rolling patient transfer device  112  may include an adjustable inner column such that the height of housing  114  may be adjusted by an attendant. In the case of the embodiment shown in FIGS. 18A-D, the handle  128  may be manipulated by a motion, such as a jack pumping motion, to activate the elevating mechanism  138  and thereby adjust the housing  114  to the appropriate height for the patient reposition or transfer. 
     Referring to FIGS. 19A and B,  20 , and  21 , rolling patient transfer device  112  may include one or more clamping members  150  that may be employed to provide additional securing features and stability to the rolling transfer device  112  while performing a patient transfer or reposition. Additionally, the clamping members  150  may also be utilized to secure a patient transfer device  112  to the patient support  46  for the transport of the entire patient support  46  with or without a patient. 
     Referring to FIG. 19A, an operator may guide the rolling patient transfer device  112  in proximity to the patient support  46  such that clamping member  150  is proximate to patient support member  152 . Upon contact with the patient support member  152  the clamping member  150  is actuated. Referring to FIGS. 19A and B, it is noted that clamping member  150  may be optionally actuated by a foot pedal  154 . Actuation of the clamping member  150  closes the clamping member  150  and secures by grasping the patient support member  152  against fixed member  148 . Once the rolling transfer device  112  is secured, as depicted in FIG. 21, an attendant may ergonomically perform the patient reposition/transfer or perform the movement of the entire patient support  46 . 
     Referring to FIGS. 30 and 31A and B, in use, bed  902  and cart  904  are aligned and may be secured together. If a patient is to be transferred from bed  902  onto cart  904 , clamp  914  is attached to a transfer sheet upon which the patient is disposed. The straps  918  attached to clamp  914  have been routed under bed  902  and cart  904 , then upwards, and then horizontally by means of perpendicular transfer units  910  and  912 . Once motor-winch unit  906  is activated, straps  918  are retracted. The transfer force exerted thereby will transport the patient in the direction of arrow  926  from bed  902  onto cart  904 . Once the patient has been transferred onto cart  904 , motor-winch unit  906  is disengaged. Alternatively, a sensing device (not shown) may be attached to perpendicular transfer unit  910 . This sensing device may be either mechanical, electronic, magnetic, optical or a combination thereof in its operation and may detect the presence of the patient, the buckle, the strap portion proximate the buckle, or the clamp within a predetermined distance from perpendicular transfer unit  910 . 
     If the patient is to be transferred from cart  904  onto bed  902 , straps  918  are routed through perpendicular transfer unit  908  and onto mattress  915  where they are attached to clamp  914 . Clamp  914  is then securely attached to a transfer sheet upon which the patient is disposed. Motor-winch unit  906  is then activated, thereby retracting strap  918  in the direction of arrow  930 , thereby generating a transfer force upon clamp  914 . The transfer force acts upon the transfer sheet upon which the patient is disposed, thereby transferring the patient from cart  904  onto bed  902  and thereby further, or additionally, gripping the transfer sheet secured within clamp  914 . Again, patient proximity sensing devices may be included in perpendicular transfer unit  908  as discussed hereinabove. Perpendicular transfer units  908 ,  910 , and  912  may include either a pulley system or a roller system onto which straps  918  are emplaced prior to a patient transfer. Clamp  914  may be any of the clamps disclosed herein. Some exemplary embodiments of motor-winch unit  906  are discussed in more detail herein. 
     The present invention may be embodied in other specific forms without departing from the spirit of the essential attributes thereof; therefore, the illustrated embodiments should be considered in all respects as illustrative and not restrictive, reference being made to the appended claims rather than to the foregoing description to indicate the scope of the invention.