Abstract:
A flat backboard for an injured person to lie upon is supported between two rigid support poles. The support poles are connected at each end of the stretcher to each other by an elevated support assembly. The support assembly has a handlebar structure and a mount assembly; this mount assembly has a central axle, around which the handlebar assembly fits, allowing for the handlebars to rotate without the mount assembly or the backboard rotating. When the holder of the handlebars generates a rocking motion, the central shaft rotates in the mount assembly, such that the weight of the injured person is supported by the mount assembly, but the rocking motion is not communicated to the mount assembly or the backboard.

Description:
FIELD OF THE INVENTION 
     This invention relates to a stretcher for transportation of injured persons, and in particular to a stretcher or stretcher-attachment with a weight-stabilizing feature. 
     BACKGROUND 
     Stretchers are typically used for medical evacuation of injured persons from the site of injury to a medical vehicle such as an ambulance or helicopter. Some stretchers are intended to be highly portable, to be carried long distances by military or emergency personnel into regions inaccessible by vehicular transport; others are intended to be used in environments that are easily accessible by vehicle, and are correspondingly heavier; others, such as wheeled hospital gurneys, are designed with wheels and stands that can be used on level surfaces. 
     Often, injured persons are subject to jostling and rocking during transport on a standard stretcher. Lateral rotation is generated any time the persons transporting the stretcher are traveling on uneven terrain or are climbing up or down a grade. Even when the person on the stretcher is firmly strapped to the backboard, any rocking motion on the part of the persons holding the stretcher on either side is transmitted to the backboard. This is particularly problematic for back and spine injuries, but can be a problem for persons with all types of injuries. 
     Indeed, the reduction of unnecessary back and spinal motion is a standard part of modern emergency medical procedure. A common device used for this purpose is a long spine board, also called a backboard and made of plastic or other X-ray translucent materials, on which the injured person is placed. Other devices such as a cervical collar, side head supports or blocks, and straps are used in conjunction to immobilize the patient. In cases where rapid vehicle extraction is desired, often devices are used such as the Kendrick Extrication Device, which is a padded device with built-in straps designed to immobilize a person in an anatomically neutral position. 
     However, such immobilizing devices are not useful in reducing back and spinal motion due to motion of the stretcher, as the immobilizing devices themselves are only secured to the stretcher. What is needed is a mechanism for separating the rocking motion of the persons carrying the stretcher from the actual stretcher itself. 
     SUMMARY 
     In some embodiments, a flat backboard for the injured person to lie upon is supported between two rigid support poles. At each end, the support poles connect to a support assembly. The support assembly includes a handlebar structure and a mount assembly. The mount assembly connects to the support poles and includes an axle parallel to the orientation of the stretcher onto which the handlebar assembly is fitted, to provide a pivot joint. The pivot joint allows the handlebars to rotate without the mount assembly or the backboard rotating. When the movement of a holder of the handlebars causes the handlebars to rock or tilt, the handlebar structure rotates about the axle of the mount assembly, such that the weight of the injured person is supported by the joint, but the rocking motion is not communicated to the backboard. This separates the rocking motion of the persons carrying the stretcher from the actual stretcher itself and the patient lying on the stretcher. 
     In other embodiments, the invention includes a support assembly configured to be connected to an end of a backboard stretcher. The support assembly includes a handlebar structure and a mount assembly. The mount assembly is configured to connect to an end of the stretcher, and includes an axle onto which the handlebar assembly is fitted, to provide a pivot joint. 
     In other embodiments, the invention includes a weight-stabilizing assembly that includes a mount assembly adapted for coupling with a load-bearing structure, such as a stretcher, a handlebar, and a detachable pivot joint rotatably coupling the handlebar to the mount assembly. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective drawing of a complete stretcher assembly with backboard and handlebar attached via a pivot joint, according to an embodiment of the invention. 
         FIG. 2  is a perspective drawing of the handlebar of  FIG. 1 . 
         FIG. 3  is a perspective drawing of the backboard of  FIG. 1 , upon which the injured person is placed and immobilized. 
         FIG. 4  is a perspective drawing of the pivot joint and surrounding structures of  FIG. 1 . 
         FIG. 5  is a perspective drawing of an alternative design. 
         FIG. 6  is a perspective drawing of the alternative design of  FIG. 5 , showing the stretcher separated into pieces. 
     
    
    
     DETAILED DESCRIPTION 
     A stretcher for weight stabilization is provided, often for use in field environments. 
     As shown in  FIG. 1 , a stretcher  100  includes a backboard  102  supported between two support poles  104 ,  106  which are coupled on each end to a support assembly  108 . The support assembly  108  includes a mount assembly  110  coupled to poles  104 ,  106 . Mount assembly  110  also is coupled at a pivot joint  112  to handlebars  114 . Handlebars  114  otherwise are not coupled to the backboard  102 . As shown in  FIGS. 1 and 2 , pivot joint  112  has a rotational axis A. As the handlebars  114  are rotated around the pivot joint  112 , the rotational motion is isolated to the handlebars  114 , and is not transmitted to the rest of the stretcher  100 . 
     As shown in  FIG. 2 , each mount assembly  110  includes two parallel arched pieces  118 ,  120 ; the top or peak of each arched piece  118 ,  120  is joined by axle  122 . The bottom ends of inner arched piece  120  is connected to left and right inner horizontal pieces  128  and  132 . The bottom ends of outer arched piece  118  are connected to outer left and right horizontal pieces  130  and  134 . Inner horizontal pieces  128  and  132  are coupled to poles  104 ,  106 . Left horizontal pieces  128  and  130  may be connected together or may be formed as a single piece. Similarly, right horizontal pieces  132  and  134  may be connected together or may be formed as a single piece. 
     As shown in  FIGS. 2 and 3 , each handlebar  114  includes inner crossbar  124  and outer crossbar  126  connecting left handle  136  and right handle  138 . Inner crossbar  124  includes an opening  140  along rotational axis A. the main longitudinal axis of the stretcher, and outer crossbar  126  includes two openings  142 ,  144  along the rotational axis A. The opening  140  in inner crossbar  124  only exists on one side, to accommodate an end of axle  122 . The openings  142 ,  144  in outer crossbar  126  provide a passage to accommodate axle  122  for pivot joint  112 . The openings in inner crossbar  124  and outer crossbar  126  allow handlebars  114  to rotate about axle  122 . Together, outer crossbar  126  and axle  122  form pivot joint  112 . 
     The pivot joint  112  has one degree of freedom, which is rotation along rotational axis A. The pivot joint  112  optionally includes ball bearings. The pivot joint may be constructed in the form of a hinge connecting handlebars  114  and mount assembly  110 . The hinge may allow only a limited angle of rotation about rotational axis A. The handlebars  114  rotate about the hinge relative to mount assembly  110 . In some embodiments, the hinge includes axle  122 . In other embodiments, axle  122  is omitted. In different embodiments, the pivot joint  112  may provide a looser or tighter fit between the crossbars  124 ,  126  and axle  122 , such that different levels of damping are provided to the person on the stretcher. In some embodiments, a shell on handlebar  114  or mount assembly  110  may surround any otherwise exposed portion of axle  122  to lessen the chance that debris enters the pivot joint  112 . 
     In some embodiments, left handle  136  and right handle  138  are spaced by a width that is optimized for a person carrying the device, i.e., roughly shoulder-width apart. This width may be somewhat greater or less than the distance between the two support poles  104 ,  106  which support the backboard  102 . In some embodiments, handles  136 ,  138  are equipped with grips  146 , which provide comfort and support for the persons carrying the stretcher. Although two crossbars  124 ,  126  are shown, in other embodiments a single crossbar can be used. 
     In some embodiments, the handlebars  114 , in conjunction with mount assembly  110 , provide a limited range of motion, thereby preventing large rotations that could cause the person on the stretcher to fall out. Angled portion  116  on either side of arched pieces  118 ,  120  stops handle  136  or  138  if the stretcher rotates beyond an allowed range of motion relative to the handles. By altering the angle of angled portion  116 , or the shape of arched pieces  118  and  120 , the allowable range of motion can be increased or decreased. 
       FIG. 4  depicts the backboard  102 , upon which the injured person is laid and secured. In the depicted embodiment, notches  148  allow for the attachment of straps (not shown) for securing the person. Varying sizes of backboards are employed in various embodiments. In some embodiments, the injured person may be laid with their head positioned toward either side of the backboard. The handlebars are raised from the backboard and horizontal pieces  128 ,  130 ,  132 ,  134  by approximately eight inches, or more, to reduce the likelihood that the patient laying on the stretcher will strike the handlebars. While depicted with no crossbars between the poles  104 ,  106  at the ends of the stretcher, in an alternative embodiment, crossbars could be placed at the ends of poles  104 ,  106  or on support assembly  108  at the same level as the backboard  102 . 
     In some embodiments, horizontal pieces  128 ,  132  are hollow, and poles  104 ,  106  fit into the hollow pieces. The joints between the support assembly  108  and the support poles  104 ,  106  may be secured with glue or other adhesive. In other embodiments, this joint may be detachable, and secured using other structures that allow for quick assembly and disassembly. For instance, interlocking tubes fastened by screws, washers and nuts, locking grooves, or other fastening mechanisms can be used; such mechanisms are well known in the art. In other embodiments, the support assembly  108  may be connected to the support poles  104 ,  106  and/or backboard  102  at multiple points. 
     In some embodiments, a single arched piece is used instead of two. In different embodiments the support assembly  108  can be provided as part of the stretcher or as a separate component that is added to an otherwise finished stretcher. In some embodiments, the device is formed using aluminum, such as hollow aluminum tubes; in other embodiments, different materials, such as plastic and/or other lightweight metals, are used. 
     In some embodiments, hooks enabling the attachment of tools and medical supplies are provided at different points on the stretcher, such as on mount assembly  110 , handlebar  114 , or support poles  104 ,  106 . In other embodiments, a harness is attached to the stretcher to allow persons carrying the stretcher partially to support the weight of the stretcher with their bodies as well as by carrying with their arms. The harness may be attached at handlebar  114  or mount assembly  110 . The harness may attach at the handlebar on the side opposite from the arm or shoulder it is supported by, thereby crossing the holder. 
     In yet another embodiment, the backboard  102  and support poles  104 ,  106  are collapsible to facilitate transportation of the stretcher into remote areas. For example, the backboard and support poles may be designed to separate into three or more interlocking segments, such as by using hollow pipes, such that the pipes fit into each other for ease of transportation. When the stretcher is assembled, the pipes can be fastened with screws, pins, nuts or other fasteners as is well-known in the art. 
     An alternative embodiment is shown in  FIG. 5 . In this embodiment, stretcher  200  includes backboard  202  supported around its perimeter by frame  260 . Frame  260  includes side poles  204 ,  206 , and on each end inner pole  262  and outer pole  264 . Support assembly  208  includes handlebar  270 , inner handle support  272 , and outer handle support  274 . Handlebar  270  has an “A” shape, with two crosspieces: inner crosspiece  280  and outer crosspiece  282 . Handlebar  270  also includes post  292  extending from the apex  290  of the “A” to inner crosspiece  280 , and post  294  extending from inner crosspiece  280  to outer crosspiece  282 . Posts  292  and  294  are co-linear. Inner handle support  272  includes an opening at its top to accommodate post  292 , and outer handle support  274  includes an opening at its top to accommodate post  294 . Handlebar  270  is able to rotate within the openings in inner handle support  272  and outer handle support  274 . 
     As shown in  FIG. 6 , stretcher  200  can be separated into pieces  252 ,  254 ,  256  for easier transportation. Inner pole  262 , outer pole  264 , and support assembly  208  remain part of end pieces  284  or  286 . To assemble stretcher  200 , the three pieces  252 ,  254 ,  256  are arranged in sequence, and then the individual components of side poles  204 ,  206  are inserted into the adjacent components and fastened with screws or bolts. 
     Unlike the embodiment disclosed in  FIGS. 1-4 , the embodiment of  FIG. 5  does not use an axle on the mount assembly. Instead, the embodiment of  FIG. 5  has posts  292 ,  294  on handlebar  270  to permit handlebar  270  to rotate within the openings in handle supports  272 ,  274 . Additionally, with the embodiment disclosed in  FIGS. 1-4 , unlike with the handle supports  272 ,  274  of the embodiment disclosed in  FIG. 5 , arched pieces  118 ,  120  extend to the sides of the stretcher, out of the way of the head of a patient or other medical supplies on the stretcher. The embodiment disclosed in  FIGS. 1-4  does not include the two parallel poles  262 ,  264  beneath the mount assembly that extend from side to side, and that are present in the embodiment disclosed in  FIG. 5 . This permits the embodiment disclosed in  FIGS. 1-4  to use less material, reducing the cost and weight. 
     In the embodiment of  FIG. 5 , unlike the embodiment disclosed in  FIGS. 1-4 , the support assembly is not detachable from the stretcher. Rather, as shown in  FIG. 5 , the mount assembly is integral with poles  262 ,  264  of stretcher frame  260 . In a further alternative embodiment, a detachable support assembly, as disclosed in  FIGS. 1-4 , could be combined with a stretcher that can be separated into multiple pieces, as shown in  FIGS. 5 and 6 . 
     Although the above description has been presented in the content of a stretcher or support assembly for attachment to a stretcher, in some embodiments the support assembly is attached to load-bearing structures other than stretchers, such as pallets of goods, chairs, trunks, or light machinery. Such embodiments are particularly useful on terrain where wheeled carriers are not appropriate. 
     Other embodiments are also within the scope of the present invention. Although the invention has been described and illustrated in the foregoing illustrative embodiments, it will be understood that extensions and modifications of the ideas presented above are comprehended and should be within the reach of one versed in the art upon reviewing the present disclosure. Accordingly, the scope of the present invention in its various aspects should not be limited by the examples presented above. The individual aspects of the present invention, and the entirety of the invention, should be regarded so as to allow for such design modifications and future developments. The present invention is limited only by the claims that follow.