US Patent 7234384 Pneumatic booster with shifted valve seats

A pneumatic brake booster (10) for a motor vehicle comprising a casing (12) within a moving partition (14) is secured to a moving piston (12) having an inlet valve (52) and a re-equalizing valve (50) with offset seats borne by first (136) and second (142) tubular sleeves, The first sleeve (136) is slideably mounted in the moving piston (22) with a travel (d) which is determined by first bayonet-fitting (154) that is interposed between the first sleeve (136) and the moving piston (22) and that are locked against rotation by the second sleeve (142).