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Published 2003 ·
OF THE DISCLOSURE A gas Spring for a drawing table which has a cylinder, a piston in the cylinder, and a piston rod projecting from the piston through one end wall of the cylinder, the other end wall being imperforate. Gas under pressure fills the cylinder and may be released from the chamber adjacent the piston rod if the latter is almost fully expelled from the cylinder against a compression spring through a chan nel having orifices in the piston and in the piston rod. Additional gas is admitted to the cylinder of a modified Spring when the piston rod is almost fully retracted into the cylinder and the piston strikes a normally closed valve Separating the cylinder cavity from a storage chamber. SLSSSMSSSLSSSSTSSSTSS The present invention relates to a weight-compensating and equilibrium-maintaining device, and it is the principal object of this invention to provide a very simple and inexpensive device in the form of a so-called gas spring for compensating the weight or maintaining the equi librium of any device or apparatus which is adjustable to different levels or inclinations and for permitting such adjustments to be carried out with the least possible physi cal effort. Among the numerous types of devices and appa ratus to which the present invention may be applied may be mentioned especially: drawing tables, X-ray apparatus, hair driers, tilting doors and windows, covers for large freezer chests, and so forth. In connection with such devices or apparatus it is con ventionai to balance their weight or to maintain their equi librium by the provision of counterweights or coil springs. The employment of counterweights has the disadvantage that they require considerable space and also considerably increase the weight of the entire apparatus. The use of coil springs, on the other hand, has the disadvantage that the operations of compressing or expanding such springs require a considerable force and either require or result in considerable changes inforce which have to be compen sated by special mechanical means such as levers, cams, or other force-transmitting means which considerably in crease the cost of the respective apparatus. Another device which has previously been employed for the above-mentioned purposes is a so-called gas spring which consists of a pneumatic cylinder and piston unit in which the cylinder is filled with a pressure gas, for exam ple, compressed air. Although very successful when spe cially designed for a specific apparatus, these gas springs have the disadvantage that each of them has a very par ticular spring characteristic and that therefore a large number of different gas springs have to be produced and be held available for compensating the different forces of different devices or apparatus and even for compen sating differences in force which might be due to inac curacies of manufacture of an individual apparatus of a series thereof. When such gas springs are to be installed, for example, on a drawing table, it is evident that dif ferent gas springs would be required either for merely balancing the weight of the drawing board itself or for 0.