front and back perspective views of a large body stretcher 100 according to the present invention are shown by fig1 and 2 . the stretcher 100 when fully unfolded in a first condition as shown provides a substantially planar patient support surface 101 that comprises a first board 102 and a second board 104 . first and second hinges 106 and 108 connect the first board 102 and the second board 104 along opposed longitudinal sides 103 such that the first and second boards may fold back against each other to a second condition indicated by the dashed lines in fig3 thereby conserving space . for other embodiments , the first board 102 may connect to the second board 104 with other securing arrangements such as , for example , bolting , pinning , screwing and the like . the first and second hinges 106 and 108 provide structural support to the stretcher when in the fully unfolded condition providing the patient support surface 101 . additional structural support is provided to the stretcher 100 by the hinged side 103 of each board 102 and 104 having integral finger and knuckle portions 107 and 109 , respectively , which is best illustrated by fig3 . the finger and knuckle portions 107 and 109 alternate such that each of the finger portions 107 of the first and second boards 102 and 104 rests upon a corresponding knuckle portion 109 provided on the opposing board , thereby adding supportive strength and spinal support to the stretcher 100 when positioned in the first condition . the lateral width of the stretcher 100 is such to permit the stretcher to maneuver through common doorways , and is preferably about 34 inches . additionally , such a lateral dimensioning would also permit the stretcher 100 to fold and easily stow , such as , for example , in an existing backboard compartment in a typical ambulance . furthermore , while the stretcher 100 is generally suited for carrying large persons , the extra lateral dimensions of the platform make it ideally suited to providing additional surface area for equipment , including cardio equipment , intravenous equipment , and the like . often times , extra equipment is required in the treatment of a patient . where hoses , tubes , electronic devices and the like are used , it is preferable to place the equipment as near the patient as possible , to avoid inadvertently bumping into such equipment by the emergency care givers while working in the narrow constraints of an emergency vehicle . moreover , it should become apparent to those skilled person skilled in related art , that the stretcher 100 may also be used advantageously as a field table , such as used for triage , operations , decontaminations , and the like . the longitudinal length can be selected to meet the needs of the specific user requirements , and further , to meet any specialized needs of a host rollable cot 126 ( fig4 ), such as those carried by an ambulance , such that the stretcher 100 may mount thereon . for example , a preferably length of approximately 76 inches would be suitable for a number of applications . the first and second boards 102 and 104 each include a backrest portion 110 a and 110 b , respectively . each backrest portion 110 a and 110 b is rotatably mounted to its respective board 102 or 104 at an end via a hinging arrangement 111 . the hinging arrangement 111 permits each backrest portion to rotate about a lateral axis from a position flush with its respective board as illustrated in fig1 to a raised position as illustrated in fig4 . a supportive edge 113 ( fig2 ) of each board 102 and 104 , and integral finger and knuckle portions 107 and 109 of each backrest portion 110 a and 110 b operate together to prevent the backrest portions from rotating below the patient support surface 101 . additionally , the supportive edge 113 and the finger and knuckle portions 107 and 109 provide support to the backrest portions when the stretcher 100 is in the fully unfolded condition . with the stretcher 100 fully unfolded , the backrest portions 110 a and 110 b together form a rotatable backrest 110 . as illustrated by fig4 the rotatable backrest 110 permits the host cot &# 39 ; s backrest 127 to be placed in a raised position when the stretcher 100 is secured to the host cot 126 such that a patient carried thereon may be positioned in an upright or seated position . in another embodiment , each backrest portion 110 a and 110 b is removably attached to its respective board such that it maybe removed , if desire , to permit the backrest 127 of the host cot 126 to be raised through the space therein provided in the stretcher 100 . preferably , the maximum load capacity for the platform 100 is about 600 - pound . in order to allow attendants to carry a large - bodied patient of about 600 - pounds upon the patient support surface 101 , the stretcher 100 contains a plurality of handholds 114 spaced around and adjacent to the stretcher &# 39 ; s periphery 112 . for other embodiments , the maximum load capacity and number of handholds can vary depending upon the required application and stretcher dimensions . it is to be appreciated that the handholds 114 are provided adjacent the patient support surface 101 such that the handhold 114 are spaced a distance for the work surface upon which the stretcher is supported . such a handhold arrangement allows the attendants to grasp more easily the handholds 114 and to gain a mechanical advantage for lifting the stretcher 100 . in other embodiments , integral footpads positioned along the back or underside of the stretcher 100 may be provided to suspend the stretcher in a slightly raised position with respect to the work surface . for applications where load capacities are expected above 600 pounds , the stretcher 100 may be provided with movable crossbars in order to further strengthen the stretcher 100 while in the fully unfolded condition . in such an embodiment , the crossbars are positioned substantially laterally along the stretcher where extra support is needed , and are indicated by dashed lines 118 and 120 in fig2 . a slot or channel ( not shown ) can be provided in the boards 102 and 104 to slidably mount the crossbars 118 and 120 to the stretcher 100 . in this manner , the crossbars may be moved laterally to extend across the adjacent board when the stretcher 100 is in the fully unfolded condition . the crossbars 118 and 120 can then be secured into place in a conventional manner such as a pin , bolt , or clasp to provide added support to the stretcher 100 . referring to fig1 and 2 , the stretcher 100 includes a plurality of throughbore - pairs or retaining channels 116 for receiving or passing through straps and like restraining devices while the stretcher 100 is secured to the host cot 126 . the retaining channels 116 can be placed anywhere along the surface of the stretcher 100 as desired . the number of retaining channels 116 utilized and the positioning will be dependant upon factors such as the positioning of restraints on the host cot 126 ( fig4 ), and of the needs of the patient . referring to fig4 the stretcher 100 further includes a securing arrangement 121 to allow the platform 100 to mount to the host cot 126 . in one embodiment , the securing arrangement 121 comprises a plurality of legs 122 rotatably mounted to the underside of the stretcher 100 . in this embodiment , the legs 122 fold from a stowed position substantially parallel to the stretcher 100 , illustrated by the dashed lines , to an extended position , which places the legs 122 substantially perpendicular to the stretcher 100 as illustrated in fig4 . any suitable locking arrangement can be used to secure the legs 122 in both the extended and stowed positions . with the legs 122 placed in the extended position , the stretcher 100 may then be advantageously releasable mounted to the host cot via receptacle members 128 provided on the host cot 126 . referring to fig2 in another embodiment , the securing arrangement 121 comprises a plurality of removable y - shaped legs 122 which are locatable by first ends 123 in mounting channels 124 of the stretcher 100 . second ends 125 of the legs 122 mated with the receptacle members 128 either provided to the host cot 126 directly or secured to the host cot through the use of clamps , bolts or the like . preferably , the second end 125 of each leg 122 has a dovetail configuration which mates to an oppositely shaped socket 127 of the receptacle member 128 , and secures therein , such as with pins , latches , and the like . in a preferred use , the legs 122 are mounted first to the host cot 126 , via the provided receptacle members 128 . next , the stretcher 100 is positioned down on the legs 122 by looking down through the mounting channels 124 from the support surface 101 of the stretcher 100 . as shown in fig5 illustrating a cross section of the stretcher and one of the legs 122 taken along line 5 — 5 , the leg 122 is accommodated in its respective mounting channels 124 such that its first end 123 is engaged between its forks 131 by a brace member 130 of the stretcher . as illustrated in fig1 the brace member 130 spans the width of the mounting channel 124 . a securing bar 132 is used to releasably secure the stretcher 100 to the leg 122 . it is to be appreciated that for this embodiment , all the legs 122 are secured to the stretcher in the same manner as described above . in a secure position , the securing bar 132 extends through a securing cavity 134 provided in the leg 122 . the securing bar 132 holds the leg 122 fast to the stretcher 100 due to its oval or racetrack shape being unable to slip between a channel 133 provided between the forks 131 of the leg . in a release position , the securing bar 132 is rotated about ninety degrees , which is indicated by the dashed - lines , such that the securing bar 132 may slip through the channel 133 , thereby releasing the leg 122 from the mounting channel 124 . it is to be appreciated that each board 102 and 104 includes a securing bar 132 that may be manually moved between the secure position and the release position , via included actuators 136 ( fig1 ). moving one of the actuators 136 from the illustrated secured position to the release position , illustrated by the dashed lines in fig1 rotates the associated securing bar 132 about ninety degrees , thereby permitting the removal of all the legs 122 accommodated within the mounting channels 124 on the respective board 102 or 104 . accordingly , moving the actuators 136 to the secured position , will secure all the legs 122 accommodate within the mounting channels 124 to the stretcher 100 . referring to fig6 a lateral extender board 138 having also a plurality of finger and knuckle portions 107 and 109 may be provided to extend the dimensions of the stretcher 100 for situations in which an even larger area patient support surface 101 ( fig1 ) is required . in this embodiment , the hinge 106 ( fig2 ) is configured to allow the first board 102 to separate from the second board 104 through the removal of a retaining pin or the like . additionally , alternative means can be used to releasably secure the first board 102 to the second board 104 including bolts , brackets , clamps , and the like . preferably , in this embodiment the hinge 106 allows for rapid conversion by releasably securing and permitting the boards 102 and 104 to extend along the longitudinal side 103 ( fig3 ) similar in fashion to the method used to add a centerboard to enlarge a dinning room table . accordingly , telescoping member lateral support members 139 permit the first board 102 and second board 104 to be extended and retracted . after releasing a locking device holding the boards together along the longitudinal side 103 , by applying a force on the first board 102 in the direction of arrow 144 , and applying a force to the second board 104 in the direction of arrow 146 , the lateral extender board 138 may be placed between the boards . then transitioning the first and second boards 102 and 104 in the direction of arrows 140 and 142 , respectively , the longitudinal edges of the lateral extender board 138 are thereby secured between the boards . re - securing the locking device will prevent further lateral movement of the boards 102 and 104 while the lateral extender board 138 is in use . in this manner the stretcher 100 can have a nominal lateral dimension , such as for example , of approximately 34 inches in an unfolded position , which then can be extended laterally , such as for example , by an additional 10 inches by inserting lateral extender board 138 . the boards 102 and 104 , the backrest portion 110 a and 110 b , and the lateral extender boar 138 of the stretcher 100 are made of a molded non - porous material , such as a polymer , and preferably , polyethylene plastic or other suitable material and utilizes a rotational molding procedure . it is to be appreciated that using rotational molding permits the formation of both a lightweight and durable stretcher 100 . additionally , it is to be appreciated that forming the portions of the stretcher 100 by rotation molding also has a number of inherent design strengths , such as consistent wall thickness and strong corners that are virtually stress free . furthermore , should additional strength be required , reinforcing ribs can be designed and molded into each portion of the stretcher . alternatively , the portions of the stretcher 100 may be blow molded , injection molded , and / or constructed of metal . in operation , where an emergency care provider recognizes the need for a large platform , the stretcher 100 is removed from its storage location ; for example , a backboard storage compartment provided on an emergency transport . the stretcher 100 is then transported to its desired location . it should be pointed out that the present invention is useable as a standalone stretcher , or as a platform extender for a host cot 126 . therefore , the present invention can be unpacked and immediately assembled to the host cot 126 by unfolding the stretcher 100 , positioning it over the host cot 126 , and then securing the platform to the host cot 126 using the provided securing arrangement 121 . alternatively , the stretcher 100 may be transported to the desired location by carrying it in either the folded , or the fully unfolded condition . upon attaining the desired location , if not already completed , the stretcher 100 is unfolded by unfolding the first portion 102 from the second portion 104 . the patient is placed upon the platform 100 , secured in place with restraining straps connected or passing through the retaining channels 116 , and then lifted by grasping the stretcher 100 along handholds 114 . upon returning to the ambulance , the stretcher is secured to the host cot 126 using the provided securing arrangement 121 . once the stretcher is secured to the host cot 126 , the cot is loaded into the ambulance or other transportation vehicle . because the stretcher 100 does not interfere with or inhibit locking devices used to secure the host cot 126 within the ambulance , such locking devices may be used in order to transport safely and effectively the patient upon the connected stretcher 100 and host cot 126 to an emergency facility . in the foregoing specification , the invention has been described with reference to specific exemplary embodiments thereof . it should be appreciated that various modifications and changes may be made thereto without departing from the broader spirit and scope of the invention as set forth in the appended claims . the specification and drawings are , accordingly , to be regarded in an illustrative rather than a restrictive sense .