Abstract:
This invention relates to a wheeled stretcher in which the plane on which the patient lies is adaptable in height, comprising a frame on which is fixed a top element and which rests on the ground via a support provided with wheels, wherein each leg of the support is connected to the frame by a connecting rod articulated respectively on the frame and on the leg, said rod being connected to means for adjusting the top element in height and said leg being connected to a means for maintaining and inclining the top element.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a wheeled stretcher in which the plane on which the patient lies is adaptable in height. 
     Wheeled stretchers are known, which comprise a top element on which the person to be transported is lain and which is mounted on a wheeled support enabling said stretcher to be moved over the ground. However, it is very important to adapt the height of the top element on which the patient lies with respect to another plane on which the stretcher is to be displaced, particularly the floor of an ambulance. 
     When adapting the height of the top element, difficulties are encountered in obtaining a displacement during which the plane of said top element remains perfectly horizontal. 
     Furthermore, it is difficult to house the control means on the frame of the top element without hindering folding of the legs of the support. 
     SUMMARY OF THE INVENTION 
     According to the present invention, each leg of the support is connected to the frame by a connecting rod articulated respectively on the frame and on the leg, said rod being connected to means for adjusting the top element in height and said leg being connected to a means for maintaining and inclining the top element. 
     This arrangement according to the invention allows the horizontal elevation of the plane of the top element from one control element only and without hindering the zones reserved for the legs of the support. The device further comprises a means for adjusting the inclination of the top element so as to place the person transported in a determined position. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be more readily understood on reading the following description with reference to the accompanying drawings, in which: 
     FIG. 1 is a schematic view in elevation and in section along line I--I of FIG. 2 of an embodiment of a wheeled stretcher according to the invention. 
     FIG. 2 is a plan view of the wheeled stretcher shown in FIG. 1. 
     FIG. 3 is a schematic view in elevation and in section along line III--III of FIG. 2 of the wheeled stretcher. 
     FIG. 4 is a bottom view along line IV--IV of FIG. 1. 
     FIG. 5 is a perspective view of the device for controlling the displacement of the top element in height. 
     FIG. 6 is a side view of the stretcher showing a frame of the stretcher at two different elevations. 
     FIG. 7 is a side view of the stretcher showing the legs thereof in a collapsed position. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings, FIGS. 1 to 4 show an embodiment of a wheeled stretcher according to the invention which comprises a frame 1 on which is fixed a top element 2 adapted to receive a recumbent person. 
     The frame 1 is constituted by two longitudinal elements 3, 3a joined together by crosspieces 4, 5 constituted by boxes adapted to receive part of the mechanism. At the ends of the longitudinal elements are provided handles 6 for guiding the stretcher. On the frame 1 are mounted, in articulated manner, two pairs of legs 7, 7a connected together by a crosspiece 15, 15a and which rest on the ground via wheels 8 allowing the stretcher to be displaced. 
     At one of the ends of the longitudinal elements 3, 3a are provided support members 9 bearing wheels 10 adapted to come into contact with any plane, particularly the floor of an ambulance into which the stretcher is loaded. Each leg 7, 7a is connected to the frame 1 by connecting rods 11 articulated connected to a pin 12 on the leg and about a shaft 13 for pivotal movement therewith. Shaft 13 is pivotally mounted in bearings 14 fixed on the longitudinal elements 3, 3a of the frame. On the shaft 13 for articulation of each rod 11 on the longitudinal elements there is fixed a fork 16 extending inside the longitudinal elements 3, 3a and of which the branches are engaged in two notches 17, 17a provided on either side of a transmission bar 18, 18a (FIGS. 1, 2) mounted to slide in each longitudinal element 3, 3a. 
     At one of their ends, the transmission bars 18, 18a each present two notches 19, 19a in which are engaged the two branches of a fork 20 fixed to each of the ends of a shaft 21 mounted to rotate in the crosspiece 5 of the frame 1 (FIGS. 1, 2 and 5). On shaft 21 is fixed in its median part a fork joint 22 between the arms of which is pivotally mounted a nut 23 in which is engaged a threaded rod 24 mounted to rotate in a bearing 25 between two stop washers 26, 26a, said bearing being mounted in articulated manner between two brackets 27, 27a fixed beneath the crosspiece 5. 
     At its end opposite the nut, the threaded rod 24 is provided with a crank handle 28 for rotating the threaded rod 24 and for acting on the nut 23. 
     To ensure maintenance of legs 7, 7a in position and the inclination of the top element, the device comprises a bar 29 which is articulated at one of its ends about a pin 30 mounted in a fork joint 31 fixed on the crosspiece 15 connecting each pair of legs 7, 7a (FIGS. 3, 4 and 5). 
     At its other end, the bar 29 is articulated about a pin 32 fast with a swivel joint 33 mounted in a corresponding housing in one of the arms of a square 34 of which the other arm bears a pin 35 mounted to rotate in a bearing 36 fixed in the crosspiece 4 and 5. The pin 35 rotates with a crossbar 37 of which one of the ends is articulated on the rod of a pneumatic damper 38 employing gas, and of which the other end is articulated on the rod of a damper 39, dampers 38 and 39 being fixed on the crosspiece 5 by an articulation. 
     One of the dampers 38 is controlled by a means for annulling and re-establishing the elastic effect of the gas in order to displace the piston to modify the inclination of legs 7, 7a with respect to the frame and then to ensure maintenance of the legs in position. 
     On the crosspiece 5 is mounted, in articulated manner, about pins 40, 40a, a stop member 41 constituted by a U-shaped bar adapted to come into abutment against the legs when they are folded. 
     The device according to the invention operates as follows: as the top element on which the patient lies is at a determined height, it may be necessary to bring it to another level particularly to load the stretcher into an ambulance. To that end, the crank handle 28 is actuated in order to rotate the threaded rod 24 (FIG. 5) and to displace the nut 23 longitudinally with respect to the screw. 
     The nut 23 being articulated in the fork joint 22, it rotates the shaft 21 pivotally mounted in bearings on the crosspiece 5. 
     Similarly, the forks 20 fast with the shaft 21 are also driven in rotation and act via notches 19, 19a on the bars 18, 18a which slide longitudinally in the longitudinal elements 3, 3a. 
     Bars 18, 18a presenting notches 17, 17a in which are engaged the forks 16 fast with the shafts 13, this results in a conversion of movement ensuring the rotation of the connecting rods 11. As the legs 7, 7a are maintained by the bar 29 and the dampers 38, 39, a variation in height is obtained of the top element 2 with respect to the ground on which the wheels rest, as shown in FIG. 6, allowing the wheels 10 to slide onto the floor or tracks 42 of an ambulance 43. 
     By acting on the adjustable damper 38, particularly by means of push buttons, it is possible to modify the position of the piston which pivots the crossbar and consequently the square 34 which ensures displacement of the bar 29 and of the pair of legs 7 or 7a which pivots about pin 12 to incline the top element 2 either forwardly or rearwardly depending on which pair of legs 7 or 7a is acted upon. 
     In an extreme position, the legs 7, 7a may be folded completely against the frame 1, as shown in FIG. 7. 
     The invention is, or course, not limited to the embodiment shown and described in detail, as various modifications may be made thereto without departing from the scope thereof.