Abstract: A linear to rotary actuator is disclosed having a fluid pressure operated diaphragm whose linear movement is translated into rotary movement of an output member by a helical coupling therebetween. The coupling comprises a coupling member that is insert molded in the diaphragm so as to extend therethrough and interlock therewith while preventing fluid from passing from one diaphragm side to the other. The coupling member has a combined guide and anti-rotation portion extending from one side of the diaphragm that slidably engages a stationary guide so as to guide linear movement while preventing rotational movement of the coupling member and further has a helix extending from the other side of the diaphragm which in one embodiment slidably engages in a slot directly in the output member whereby linear movement of the diaphragm forces linear non-rotational movement of the coupling member and thereby rotary movement of the output member.

Abstract: A linear to rotary actuator is disclosed having a fluid pressure operated diaphragm whose linear movement is translated into rotary movement of an output member by a helical coupling therebetween. The coupling comprises a coupling member that is insert molded in the diaphram so as to extend therethrough and interlock therewith while preventing fluid from passing from one diaphragm side to the other. The coupling member has a combined guide and anti-rotation portion extending from one side of the diaphragm that slidably engages a stationary guide so as to guide linear movement while preventing rotational movement of the coupling member and further has a helix extending from the other side of the diaphragm that slidably engages in a slot in a section that meshes with a gear connected to the output member whereby linear movement of the diaphragm forces linear non-rotational movement of the coupling memmer and thereby rotary movement of the output member.