Housing of pneumatic booster device

Claim 1

A housing of a booster device of the type in that the inside space of the housing made elliptical in outer peripheral shape is divided by a diaphragm and a power piston into a constant-pressure chamber and a variable-pressure chamber, comprising a first shell made by subjecting a metallic plate to plastic working, and a second shell made by subjecting a metallic plate to plastic working and provided with a flange portion which is inserted in an opening portion of said first shell and clamped in place, and characterized in that on said flange portion of said second shell and on said opening portion of said first shell, mating abutting portions are formed respectively for limiting a depth of insertion of said second shell into said first shell, in said flange portion of said second shell a plurality of notches extending from the outer periphery toward the center are formed which are distributed circumferentially and spaced from one another, on said opening portion of said first shell a plurality of pawls are provided projectingly for clamping said flange portion of said second shell via a pair of U-shaped lock members disposed adjacent to the outside of said flange portion, said pawls being aligned with said notches in the axial direction of said housing and made smaller than said notches, between the inner periphery of said pair of lock members and said second shell and between opposite ends of both said lock members, gaps are left for permitting said lock members to slide a given extent, in each of said lock members notches are formed to cancel a locked relation of said lock member with said pawls as said lock member slides a given extent, and a stopper is incorporated for preventing sliding of said lock members in a normal state.