Patient support table
BACKGROUND OF THE INVENTION 
     The present invention is directed to a patient support table comprising a trestle having an upper or liftable member on which a patient support platform is mounted and a base which is connected to the upper member by a scissors jack arrangement. 
     Patient support tables of this type are employed, for example, in angiography for the representation or visualization of blood vessels. In this case, it is desirable that the patient be readily accessible to the physician from all sides. In addition, the patient support platform is mounted on a trestle having small dimensions and is capable of being lowered to a great extent in order that an easy transfer of the patient from the bed to the patient support platform is possible. In addition, the lifting height of the trestle is to be so great than an optimum working height for the physician can be obtained. 
     A patient support table of the prior art is described and disclosed in German AS No. 15 66 654. In the patient support table disclosed in this patent, the length and width of the trestle are, indeed, relatively small. However, on account of the coupling of the scissors jack to the base of the pedestal of the patient support platform, only a relatively small elevation is possible. 
     SUMMARY OF THE INVENTION 
     The object of the present invention consists in designing a patient support table of the type having a trestle having a lifting or upper member and a base interconnected by a scissors jack and which with simple construction elements, a small area for the trestle is utilized and the trestle enables both a low minimum table height and an optimum working height. 
     In order to obtain these features, the present invention is directed to an improvement in a patient support table comprising a trestle having a base interconnected by a scissors jack to a liftable or upper member on which a patient support platform is mounted for raising and lowering. The improvements comprise that both the liftable member and base consist of box-shaped parts capable of being telescopically inserted within one another and that the scissors jack are coupled to the ends of the liftable member and the base and are designed in such a fashion that their arms are capable of moving to both sides from a closed extended position in which the arms extend parallel to each other. 
     In the case of the present invention, the arms of the scissors jack are disposed approximately horizontal when the upper end of the base and the lower end of the liftable member are disposed approximately at the same level. From this position, the jacks can be pivoted in both directions so that a telescoping together of the liftable member and base is possible on the one hand and a greater separation of the lifting member from the base is also possible on the other hand. The maximum amount of movement in either direction will be determined by the dimensions of the arms of the scissors jack. The overall lifting height accordingly results from the stroke of the scissors jack which is possible from the parallel extended position toward both sides. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a plan view of the trestle for the table of the present invention without the support platform; 
     FIG. 2 is a side view of the table with the trestle mounted in the lowermost position; and 
     FIG. 3 is a side view of the table of FIG. 2 while in the uppermost position. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The principles of the present invention are particularly useful in a patient support table generally indicated at 100 in the Figures. The table 100, as best illustrated in FIG. 3, has a trestle composed of a pedestal or base 1 and an upper or liftable member 7 which supports a patient support platform 14. The base 1 has a first end 21 and a second end 22 while the upper or liftable member 7 has a first end 31 and a second end 32. The first end 21 of the base 1 supports a first scissor arm 3 on a shaft 2. A second scissor arm which consists of two support parts or arms 4a and 4b (FIG. 1), has one end connected in slots 23 in the second end 22 by bearing guides 5a and 5b, respectively. The other end of the arms 4a and 4b are connected to the first end 31 of the upper member 7 by guides or shafts 8a and 8b. The second end of the upper member or liftable member 7 has slots 33 which receive bearing guides 9a and 9b of the first arm 3. 
     It is apparent from the Figures that the base 1 and the liftable member 7 each consist of box-shaped parts capable of being telescopically arranged in each other. For example, the first end 21 of the base 1 is telescopically received in the first end 31 of the upper member 7 while the second end 32 of the upper member 7 is telescopically received inside of the second end 22 of the base 1 when the two members are in their lowermost position (see FIGS. 1 and 2). This telescopic engagement is possible because these parts are cut out in a V formation. The respectively narrow end such as the first end 21 of the base 1 is received in the wider first end 32 of the upper part 7 while the narrow second end 32 of the upper part or member is received in the wider second end of the base 1. In the lowermost position which is illustrated in FIG. 2, the guides 9a and 9b are disposed inside of the guides 5a and 5b and the shaft 2 is disposed inside of the shafts 8a and 8b. It is noted that a shaft 6 pivotably connects the arms 3 to the parts 4a and 4b and also is surrounded by the members forming the base 1 and the liftable member 7. 
     As a lift element, an electro-thrust motor 10 is provided and is connected to a shaft or pivot point 11 on the lower side of the scissor arm 3 and has the other end connected to the base 1 by a pivotal connection or shaft 12. In order to reinforce the lift drive, pneumatic springs 13 (FIG. 1) extend between the same two shafts 11 and 12. The pneumatic springs 13 are designed for a minimum load and will reduce the necessary power for the lift device. 
     It should be noted that in order to prevent being caught in the moving parts, the entire lifting system of the trestle can be covered by a telescopic tube or bellows. The safety risk is reduced by the presence of the tube or bellows. 
     It is important that the scissors jack arms 3, 4a and 4b are coupled to the ends of the liftable member 7 and to the base 1 and that they are so designed that the arms 3, 4a and 4b are capable of traveling to either side of the extended parallel position so that the parts such as the base 1 and the liftable member 7 are capable of telescopic engagement as illustrated in FIG. 2 on the one hand and can be lifted to a maximum amount of separation therebetween as illustrated in FIG. 3. Thus, the arms 3, 4a and 4b can be moved so that their ends pass through the horizontal position. 
     Although various minor modifications may be suggested by those versed in the art, it should be understood that I wish to embody within the scope of the patent granted hereon, all such modifications as reasonably and properly come within the scope of my contribution to the art.