GB936197A - Fluid motor mechanism - Google Patents

Abstract

936,197. Fluid pressure brakes. KELSEYHAYES CO. March 28, 1961, No. 11259/61. Class 103 (1). A fluid pressure servo-assisted braking system includes a fluid-pressure motor in which there is provided a resilient reaction element 80 (Figs. 2 and 4), between a manually-operable member 49 which is adapted to operate a valve mechanism 51 which normally balances pressures on opposite sides of a pressureresponsive unit 30 and is operable to connect a variable pressure chamber 64 to a source of pressure different from the atmosphere; the resilient element 80 being acted upon by a reaction member 91 fixed to the manuallyoperable member 49 and a portion 86 of the pressure responsive unit to transmit reaction to the manually-operable member to resist valve operating movement. The pressureresponsive unit comprises a stamped annular shell 31 and a co-operating diaphragm 33 clamped at its outer periphery 34 against the casing sections 11, 12 at its inner periphery 36 by a plate 37 against the shell 31. In the inoperative position shown, valve 51 is closed against the seat 50 on manually-operable member 49 attached to operating rod 46 to permit vacuum present in chamber 66, leading to a vacuum source via connection 67, to be transmitted via passages 69, 70, 62, 63 to variable pressure chamber 64 to the right of diaphragm 33. When the pedal 48 is depressed, push-rod 46 is moved to the left to move manuallyoperable member 49 until the valve 51 engages the seat 59 so that the valve elements are in a lap position. Further movement of member 49 lifts valve seat 50 away from the valve 51 to permit air to flow from ports 75 around the valve seat 50 and through passages 62 and 63 into the variable pressure chamber 64 to initiate movement of the pressure-responsive unit 30 and move axial member 18 to the left and moving hydraulic master cylinder plunger 23 to the left to pressurize the line 26 to the wheel brake cylinders 27 of the vehicle. In the lap position of the valve elements the flange 90 of reaction member 91 will lightly engage projection 83 (Fig. 4), on the resilient element 80 and further movement will slightly deform the projection 83 without appreciably resisting movement of the manually-operable member 49. Increased movement of member 49 causes the resilient element 80 to be engaged fully by flange 90 and permits reaction to the brake pedal proportional to the force being exerted by the pressure responsive unit. Flange 86 on hub 40 of the pressure-responsive member also bears against the reaction member and the flange 86 also co-operates with a flange on the axial member 18; there being a slidable connection between the member 31 and associated elements of the pressure-responsive member 30 relative to the flange 78 of the axial member 18. Specification 846,211 is referred to.