Hydraulic operating systems for clutches and the like

A variable-condition hydraulic system, comprising:

• a master cylinder including a first housing and a first piston reciprocable in and defining with a section of said housing a first fluid-containing chamber;
• a slave cylinder including a second housing and a second piston reciprocable in and defining with said second housing a second fluid-containing chamber;
• at least one hydraulic connection between said chambers;
• a source of hydraulic fluid;
• at least one conduit arranged to connect said source with said first chamber;
• and
• a seal interposed between said first piston and said section of said first housing, said seal being movable within limits relative to said first piston between a plurality of positions in dependency upon the condition of the system.

A ball and socket joint, comprising:

• a reciprocable piston;
• a connector provided on said piston and having a socket;
• a piston rod having an at least substantially spherical head received in said socket with freedom of swivelling movement;
• and
• means for securing said connector to said piston, said spherical head being disposed between an elongated portion of said piston rod and said securing means.

A ball and socket joint, comprising:

• a piston including an end portion having a concave socket;
• a piston rod having a spherical head in said socket;
• and
• a connector including a cover overlying said end portion, surrounding the piston rod adjacent said head and affixed to said piston.

A cylinder and piston unit, comprising:

• a housing;
• a piston in said housing, one of said, housing and said piston being reciprocable relative to the other thereof and at least one of said housing and said piston consisting, at least in part, of a thermosetting plastic material;
• and
• at least one seal between said piston and said housing.