Assembly of vacuum booster and master cylinder

Claim 1

In a assembly of a vacuum booster device and a master cylinder comprising a booster shell divided into a front bowl and rear bowl, a booster piston and a piston diaphragm accommodated in the booster shell, said piston diaphragm being fixed at its inner peripheral edge to said booster piston and at its outer peripheral edge being held between opposite edge portions of said front and rear bowls, a return spring arranged between said front bowl and said booster piston, a cylinder body provided on the front surface of said front bowl, and a working piston slidably fitted in said cylinder body and operatively associated with said booster piston; the improvement wherein said cylinder body includes a mounting flange adjacent said front surface of said front bowl; said front and rear bowls and mounting flange are connected together by tie rods extending through said booster piston so that any means for fastening said opposite edge portions of both of said front and rear bowls is eliminated; said tie rods extend through both of said bowls, said booster piston and said mounting flange, ne end of each said tie rod being fixedly fastened to said rear bowl while the other end thereof being tightened against said mounting flange and said front bowl with a nut screwed on said tie rod and a snap ring of thin sheet material is clipped into a reduced diameter portion of said tie rod and is opposed to the front face of said front bowl to retain said front and rear bowls assembled when said nut and said mounting flange are removed from said tie rod, said snap ring being housed in an annular recess surrounding said tie rod and in the surface of said mounting flange when said mounting flange is abutted on the front face of said front bowl by said nut so as to cause no interferences between the surfaces of said mounting flange and said front bowl when said mounting flange and said front bowl are assembled and being exposed on the front face of said bowl for removal from said tie rod when said nut and said flange are removed from said tie rod.