Patent ID: 7740227

Claim:
A joint comprising: a push rod having a protruding portion; and a main body having an upper end and a lower end spaced in a push rod longitudinal direction, said protruding portion of said push rod protruding along said push rod longitudinal direction from said upper end of said main body, a push rod storage space being formed in said main body, said push rod storage space housing said push rod, a communication path being formed in said main body at said lower end, a seal structure forming part being formed on an outer circumference of said main body at said upper end, and a male thread part being configured to thread together with a female thread part of a nut member along the push rod longitudinal direction, said seal structure forming part surrounding said push rod storage space and being configured to form a seal structure by directly contacting a first tapered part of the nut member when said female thread part and said male thread part are threaded together, a portion of said protruding portion being configured to contact a part of said nut member when installed, said push rod being movable toward said lower end of said main body along the push rod longitudinal direction to communicate with a fluid passageway of said nut member and said communication path.