Compact fluid operated cylinder and method

The method of making a miniaturized fluid operated cylinder assembly providing reduced end cap assembly length requirements comprising the steps of:

• providing a cylinder housing containing an axial cylindrical inner wall of uniform diameter extending from one end of the cylinder housing to the other containing a piston therein;
• providing a fluid inlet opening in said housing on a side of said piston for exerting a power stroke of said piston;
• forming a pair of axially spaced grooves adjacent an end of said cylinder housing in said cylindrical inner wall;
• providing an end cap for retaining fluid pressures within said cylindrical wall exerting a force tending to push said end cap outwardly many times greater than a force tending to push said end cap inwardly;
• forming a complementary groove in said end cap opposite an innermost groove of said pair of axially spaced grooves spaced so that an outer edge of said end cap leaves the other of said grooves accessibly when said complementary groove is opposite said innermost groove and an inwardly tapering circumferential surface extending from said complementary groove to an inner end of said end cap;
• inserting a resilient O-ring seal within a seat formed by said innermost groove and said complementary groove within an intermediate portion of said end cap forming a seal and securing said end cap against dislodgement inwardly of said cylinder housing;
• inserting a snap ring within said other of said spaced grooves engaging an outer surface of said end cap, an inner surface of said end cap being in engagement with said O-ring resiliently positioning said end cap in sealing engagement between said snap ring and said O-ring, and securing said end cap in spaced relation to an adjacent end of said cylinder against outward dislodgement;
• and
• inserting said O-ring seal within said seat formed by said innermost groove and inserting said snap ring within the other of said spaced grooves so that the O-ring and the snap ring continue to squeeze the end cap therebetween thus pre-loading the end cap;
• whereby said snap ring serves to prevent outward dislodgement of said end cap while said O-ring serves as a cushioning seal preventing chattering during operation and to prevent inward dislodgement of said end cap with respect to the cylinder housing.

A miniaturized fluid operated cylinder assembly providing reduced end cap assembly length requirements comprising:

• a cylinder housing having a cylindrical inner wall of uniform diameter extending from one end of the cylinder housing to the other;
• an end cap having an arcuate wall opposite, complementary to and within said cylindrical wall of said cylinder and contained entirely therein;
• a resilient O-ring sealing member carried intermediate respective end surfaces of said end cap;
• a seat for carrying said O-ring sealing member formed by complementary opposed grooves carried within said arcuate wall of the end member and said cylindrical inner wall of said cylinder housing;
• an inwardly tapered circumferential surface extending from said groove in said end member to an inside end of said end member;
• a source of high pressure fluid within said cylindrical wall for exerting a force urging said end cap outwardly of said cylinder;
• a groove within said cylindrical inner wall of said cylinder housing adjacent an outer end surface of said end cap;
• a snap ring carried in said groove at an outer end surface of said end cap;
• and
• said complementary opposed grooves accommodating said O-ring being spaced from said groove in said cylindrical wall so as to resiliently wedge the end member between the O-ring and the snap ring exerting a continuous resilient force pre-loading the end cap;
• whereby said snap ring serves to prevent outward dislodgement of end cap while said O-ring serves as a seal and to prevent inward dislodgement of said end cap with respect to the cylinder housing.