Severe duty hydraulic cylinder with continuously effective locking device
OwnerRobert B. McCreeryinventor
Life of this patent
Estimating the term…
Abstract
A hydraulic cylinder comprising a hydraulically operated power lifting ram for lifting heavy loads further includes a guide cylinder concentric about and enclosing the ram, the guide cylinder being secured to the lift platform for further support of the load and reciprocating in unison with the ram under application of hydraulic pressure. The guide cylinder is equipped with a safety locking means which prevents the hydraulic cylinder and its load from lowering in the event of a sudden loss in hydraulic pressure. The safety locking means is in contact with the guide cylinder substantially during the full stroke of the hydraulic operated ram, providing a unique method of locking the cylinder in any position within tolerances normally associated with gear driven devices.
Claims13
A hydraulic cylinder comprising a hydraulically operated ram for lifting an attached load and a safety locking means secured to said cylinder, said safety locking means capable of supporting said load at all positions during the lifting and return stroke of said ram, said hydraulically operated ram being secured to a load support means, said load support means being capable of supporting a load thereto, said hydraulical cylinder further includes a guide cylinder placed around and enclosing said ram, said guide cylinder being secured to said load support means, said ram and said guide cylinder capable of moving in unison to support said load, said ram being protected from the environment surrounding said cylinder by being totally enclosed by said guide cylinder, said safety locking means being in contact with said guide cylinder, said guide cylinder containing a groove along the exterior surface thereof, said groove extending along said exterior surface for a predetermined length over said surface, said safety locking means including a thread to match said groove, said thread being in contact with said groove substantially at all times during the movement of said guide cylinder, said safety locking means comprising a threaded nut rotatable about the exterior surface of said guide cylinder wherein rotation of said safety locking means enables the movement of said guide cylinder, said groove being a single helical groove and said thread being a matching helical thread, said safety locking means being affixed at a permanent position on said hydraulic cylinder, said guide cylinder and said ram being movable relative to said safety locking means, and an exterior outer casing surrounding said guide cylinder, said safety locking means being attached for rotation to a rotating bearing assembly attached to said exterior casing.
A hydraulic cylinder including an outer tubular cylinder portion having first and second ends and stationarily supported at said first end, a tubular piston portion having first and second ends and having its first end slidingly telescopingly engaged in said second end of said cylinder portion, said second end of said cylinder portion including seal and bearing means slidingly and sealingly engaged with the outer surface of said piston portion, means for admitting and exhausting fluid under pressure into and from the interior of said cylinder portion, a first stationary outer tubular casing having first and second ends, said first end of said outer casing being stationarily supported relative to said cylinder portion first end and loosely enclosing said cylinder portion therein, a second inner casing including first and second ends and having its first end loosely telescoped into said outer tubular casing through the second end thereof and loosely telescoped over said outer cylinder portion, said second end of said outer tubular casing including seal and bearing means slidingly and sealingly engaged with the outer surface of said inner casing, a load platform to which said first ends of said piston portion and second inner casing are secured, whereby said tubular piston portion and said inner casing are interconnected for equal and simultaneous extension and retraction relative to said tubular cylinder portion and said first outer tubular casing, said outer tubular cylinder portion being loosely received in said inner casing first end, said second end of said inner casing including low lead external thread means thereon, a safety nut journaled from said second end of said outer tubular casing and provided with low lead internal threads threaded on said thread means, and means for selectively driving said nut in opposite directions.
Dependencies are inferred from the claim text.