Patent Application
20130307231
The present invention generally relates to a portable sled and litter, and more specifically to a portable sled and litter that may be quickly assembled and disassembled.
Sled systems or sleds are commonly used in mountainous terrains or deep snow in the backcountry terrain. The ability to remove loads from the individual to a sled increases efficiency in overland movement and reduces fatigue throughout movements. Additionally, a sled enables a person to carry a load in excess of what is possible with a standard pack or load carriage system. Explorers in the Arctic and Antarctic typically tow sleds weighing between 200 to 300 pounds.
The ability to distribute weight over a larger surface area dramatically increases safety in icy or snowy environments. Should a person with a heavy backpack need to cross a questionable piece of ice covered water, the individual would need to go through a several step process to navigate the hazard. Using a sled across ice enables the individual to mitigate risk by distributing weight and removing a potential anchor in the event of a break through.
Sleds increase safety in high angle environments. Individuals are able to fill a sled with heavy or cumbersome gear, lower the load with simple rope systems, and navigate the terrain unhindered. Conventionally, hikers or mountaineers rappel with heavy loads on their backs. This method increases the risk or slips, falls, or entanglements on a descent or ascent.
Throughout the years, non-rigid litters were adapted by the military for casualty evacuations. The ability to roll a plastic litter in a small backpack enabled medics and operators to bring lifesaving equipment closer to the point of injury. Some of these non-rigid litter systems became commonly used in special operational units, conventional military units, and even non-military environments. By way of example, military units have routinely used the SKEDCO® litter system or the FOXTROT® litter system. All of the litter systems enable are providers to quickly package a patient, drag, carry, or move the patient in a high angle or rough terrain environment. Further, the non-rigid litter systems are readily portable and less expensive than conventional, rigid litter systems.
Although non-rigid litters have a great degree of advantages over rigid litters in remote or tactical environments, there are several disadvantages associated with the non-rigid litter systems. The lack of rigidity provides minimal stabilization for patients with spinal injuries, requires more litter bearers to move rapidly above ground, and is slow to rig for a high angle environment. The most frustrating trait of the non-rigid litters is the memory retained by the plastic that forms the litter itself. When a rescuer lays out the device, it needs to be held flat in order to move a patient into position. If the litter is not held on each end, it curls up into its storage position and causes unnecessary assembly delays, which may result in extra time to move the patient. Because of the standard method of dragging a patient, the non-rigid litters often become scored on the bottom, which may result in an operational life of only a few patient movements. In such an instance, the entire litter may need to be disposed of, the plastic, straps, and buckles, and then replaced with a new litter.
At least one embodiment of the present invention comprises a portable sled and litter that is easily and quickly assembled and disassembled, and when disassembled it can fit into a bag or container to be carried by a single person. Further, the portable sled and litter takes the form of a rigid litter (as compared to a non-rigid litter), and includes a plurality of rigid, interlocking panels that cooperate with a frame assembly. An inelastic cord extends through at least several frame assembly members and when tensioned causes the frame assembly members to engage with one another to form the frame assembly or at least a section of the frame assembly.
In one aspect of the present invention, a portable sled and litter includes a frame assembly having a plurality of telescoping members. At least some of the telescoping members have complementary connectable end portions for engaging with each other. The portable sled and litter further includes an inelastic cord extending through the at least some of the telescoping members, and the inelastic cord has a distal end and a proximal end. The distal end is fixed to a portion of the frame assembly (e.g., fixed to a static coupling), and the proximal end is tensionable (e.g., tensionable by manipulating an adjustable coupling) to bring the complementary connectable end portions of the telescoping members into aligned engagement. Lastly, the portable sled and litter includes a plurality of panels releasably engageable with the frame assembly, and each panel is configured to releasably interlock with at least one adjacent panel.
In another aspect of the invention, a method for assembling a portable sled and litter includes the steps of (1) arranging a plurality of frame members on a surface, the frame members comprising a frame assembly for the portable sled and litter; (2) tensioning an inelastic cord, the cord extending through at least some of the frame members, wherein the tension developed in the cord urges the frame members into an alignable engagement; (3) interlocking a plurality of panels together to form a rigid litter surface; and (4) supporting the interlocked plurality of panels on the frame assembly such that load applied onto the panels transfers to the frame assembly.
Preferred and alternative embodiments of the present invention are described in detail below with reference to the following drawings:
In the following description, certain specific details are set forth in order to provide a thorough understanding of various embodiments of the invention. However, one skilled in the art will understand that the invention may be practiced without these details. In other instances, well-known structures associated with sleds and litters to include methods of operating and/or assembling the same may not necessarily be shown or described in detail to avoid unnecessarily obscuring descriptions of the embodiments of the invention.
To address at least some of the aforementioned drawbacks of conventional litters, and in particular conventional rigid litters, at least one aspect of the present invention involves a portable sled and litter that may be quickly assembled and disassembled by one person. The portable sled and litter includes intermediate sections with interlocking tabs and may include end sections also having interlocking tabs. The respective sections may be rotated into engagement with an adjacent section as the tabs are interlocked. In one embodiment, the interlocking tabs are formed in and aligned with one or more structural ribs, gussets or raised, structural protuberances (hereinafter referred to as structural ribs) that generally extend approximately parallel with a direction of travel of the litter, or stated alternatively the structural ribs extend lengthwise with respect to the overall configuration of the portable sled and litter. The sections may include cup-shaped side portions that are configured to receive transfer load to a frame assembly. In turn, the frame assembly may take the form of cylindrical or tubular members each having a metallic, inner tube and a fiber-reinforced outer tube. An inelastic cord extends through an interior of the frame assembly. The inelastic cord is fixed to one of the frame members (i.e., a distal end of the cord) and is coupled to a toggle at a free end (i.e., proximal end of the cord). Thus, pulling on the toggle forces the respective frame members to align and engage without the assistance of another person. The frame assembly is preferably assembled as a left half frame assembly and a right half frame assembly according to the toggle pulling method described above. Then, the left and right halves may be coupled together using a structural coupler. These and other aspects of the present invention will be described in greater below.
The present invention of a portable sled and litter, according to at least one embodiment, incorporates, lightweight, abrasion-resistant, interlocking panels, a lightweight telescoping frame assembly, and a inelastic cord that permits the frame assembly to be assembled by a single person without having to physically handle and engage each frame section. In one embodiment, the Portable sled and litter may be Substantially rigid after assembled. The interlocking panels and frame may cooperate to provide high strength lifting points for rigging or transporting the litter. The high-strength lifting points may permit the portable sled and litter to securely hold a patient or gear during a high angle lifting or lowering operations. Advantageously, the portable sled and litter will enhance a caregiver's or operator's ability to move patients, navigate alpine or arctic conditions, and mitigate risk in high angle environments.
The panels 102, 104 and 106 may include openings 116 that permit the portable sled and litter 100 to be rigged or lifted, which in turn permits a weight “W” (shown as a point load vector instead of a distributed load for brevity and illustrative purposes) in the portable sled and litter 100 to be transmitted to the frame assembly 110 and then to persons carrying the portable sled and litter 100 (not shown) or to rigging equipment attached to the portable sled and litter 100 (not shown). In one embodiment, the forward panel 102 and the rear panel 104 may include openings 118, which may provide additional carrying or rigging points.
Similar to the embodiment shown in
Still referring to
Briefly referring back to
The left middle side frame member 304M may be coupled to the other side members 304F 304R, respectively, by applying tension to an inelastic cord or cable 318 that extends through an interior (not shown) of the side frame members 364. In one embodiment, the inelastic cord 304 takes the form of a steel cord, and preferably a stainless steel cord. The cord 318 is fixed to an adjustable coupling 314 and also to a static coupling 316 as will be explained in detail below with the descriptions of
Still referring to
The adjustable coupling 314 includes a threaded collar 330, a tension nut 332, a tension ring 334, a cross pin 336, and a coupling nut 338. The threaded collar 330 is bonded or otherwise adhered to the side frame member 304F and provides the means for tensioning the interior inelastic cord 318. The tension nut 332, which is rotationally decoupled from the tension ring 334 (i.e., the tension ring 334 does not rotate with the tension nut 332), rotates to advance along the threaded collar 330, and in turn urges (i.e., linearly translates) the tension ring 334. The cross pin 336 is fixed to the tension ring 334, and in turn the inelastic cord 318 is fixed to the cross pin 336, such that the linear movement of the tension ring 334 tensions the inelastic cord 318, which is anchored to the static fitting 316 as explained below. The inelastic cord 318 functions to distribute longitudinal and bending stresses among all of the frame elements, particularly in a vertical lift configuration. The coupling nut 338 may be attached to the frame assembly 300 with a flared tube end and/or an internal tenon (not shown).
Still referring to
The static coupling 316 includes a static collar 340 a static cross pin 342 and a static coupling nut 344. The static collar 340 is bonded and pinned to the most outboard side frame member and provides a static attachment point for the inelastic cord 318, which is fixed to the static cross pin 342. Likewise, the static cross pin 342 is structurally fixed to the static collar 340. The static coupling nut 344 may be attached to the frame assembly 300 with a flared tube end and/or an internal tenon (not shown) in the same or similar manner as the adjustable coupling nut 338 was attached.
While the preferred embodiment of the invention been illustrated and described, as noted above, many changes can be made without departing from the spirit and scope of the invention. Accordingly, the scope of the invention is not limited by the disclosure of the preferred embodiment. Instead, the invention should be determined entirely by reference to the claims that follow.
