Hand operated hydraulic bicycle brake

Claim 1

A hand actuated hydraulic brake for a bicycle comprising: a brake pad holder unit mounted on the bicycle, said brake pad holder unit including first and second bicycle brake housings mounted on a bracket arm to be on opposite sides of a bicycle wheel, said housing each being of a size commonly found on a bicycle, a lug mounted on said first housing, said lug having a lug groove defined therein, a fluid actuated bracket arm moving means connected to said first housing and a first brake pad connected to said second housing, said bracket arm moving means including a rolling diaphragm fluidly connected to a master cylinder by a flexible fluid line via said lug to exchange hydraulic fluid therewith, a movable brake pad holder connected to a piston rod, said piston rod including a piston head having a circumferential groove defined therein and being slidably mounted in said first housing and engaged with said rolling diaphragm for movement therewith, said rolling diaphragm including a base contacting said piston head, a side portion adjacent to said first housing and a reverse bend connecting portion connecting said diaphragm base and side portion so that said rolling diaphragm can fold upon itself within said first bicycle brake housing, said rolling diaphragm having sufficient flexibility to operate efficiently in a bicycle hydraulic brake unit, a piston rod return means engaged against said piston head to bias said diaphragm against action of hydraulic fluid forced thereinto by said master cylinder, and a second brake pad mounted on said movable brake pad holder, and said diaphragm including a first bead on the inner surface thereof which engages said lug groove to attach said diaphragm to said lug and a second bead on the outer surface thereof adjacent to said base which engages said piston head circumferential groove to attach said diaphragm to said head.