This invention relates to telescopic hydraulic cylinders, and more particularly to a double acting telescopic hydraulic cylinder construction which provides for the use of thin wall tubing and removably attachable bearing, seal, stop, wiper, guide and lifting rings, thereby eliminating welding, threading and excessive machining of cylinder tubing.
Normally, telescopic hydraulic cylinders are constructed in one of two basic ways. One way is to start with thick wall tubing and form lifting rings, stops and bearing and seal grooves thereon by machining away metal from the tubing, on appropriate inside and outside surfaces of the various cylinder components. A second typical method is to use standard wall tubing and afix by welding, threading or other means, composite annular members shaped to provide lifting rings, stops and bearing and seal grooves.
Applicant's copending patent application Ser. No. 294,818, filed Aug. 20, 1981, now abandoned discloses a telescopic hydraulic cylinder construction which utilizes a plurality of uniform thin wall steel tubings having grooves machined on the inner and outer surfaces thereof for the removable mounting of such rings. However, the construction affords only single action operation of the cylinders, whereas there are many industrial applications wherein double acting telescopic hydraulic cylinders are required or are at least advantageous.