Patent GB-497228-A (GB)
Title: Improvements in or relating to wheel brakes
IPC: B60T11/24
Filed: 1937-06-14
Abstract: 497,228. Hydraulic brakes. TAYLOR, A. G., and JEFFREYS, W. June 14, 1937, Nos. 16425/37, 22172/37, and 10165/38. [Class 103 (i)] Hydraulic brake apparatus for vehicles comprises for each wheel a master cylinder connected to a brake operating cylinder, the several master cylinders being operated by a common pedal or equivalent and to enable the pressures applied to the several brakes to be equalised or adjusted, a manually operated pressure regulator and a pressure indicator is connected to each hydraulic system. As shown in Fig. 1, a pedal operated cross-shaft 40 is connected by double-armed levers 39 and pull-rods 38 to the pistons of master-cylinders 2 each of which is connected by a pipe 3 to a wheel-brake operating-cylinder 4. Each cylinder 2 is also connected by a pipe 5 to a fluidpressure regulator 6 and a pressure indicator 7 which may be mounted on the dashboard D. Each master cylinder comprises a bellows 21, Fig. 2, clamped at its end between the end of a casting 10 and a sleeve 25 held by a casing 26 secured to the casting by bolts 30. The bellows is compressed by a piston 32 operated by lever 34 and the pull-rod 38. Connections 13, 14 are provided for the pipes 3, 5. The brake cylinders 4 may also comprise a pair of oppositely disposed bellows similarly secured within a casting bolted to the back plate of the brake, each bellows engaging a piston having a rod for operating a shoe. The inlet from the pipe 3 to the space within the bellows may be restricted to restrain the brake application. Each pressure regulator comprises a bellows 65, Fig. 5, clamped at its end between the end of a casting 64 and a sleeve 66 held by a cap 67. The bellows can be compressed by a piston 68 operated by a screw 69 and a knob 6. The bellows chamber is connected to the pipe 5 and to a pressure indicator 7. When the shaft 40 is turned by the pedal the master pistons 32 are operated to force liquid into the cylinders 4 to apply the brakes. The pressure on each brake is shown by the corresponding indicator 7 and if these pressures are unequal the corresponding pressure regulators are adjusted by turning the knobs 6. The regulators may instead be arranged beneath the floor boards of the vehicle and be adjusted by a detachable key which can be passed through holes in the boards to engage the squared ends of the screws 69, the indicators 7 being mounted on the dashboard. According .to Fig. 8, each master cylinder and its brake cylinder forms a single unit comprising a casting 100 bolted to the brake back plate 44. A pair of pistons 116 each engaging a brake shoe 118 are operated each by a diaphragm 113 clamped by a ring 114 and a screwed part 115. The two diaphragms normally abut. The master piston 106 abuts on a diaphragm 103 clamped by a sleeve 104 and a screwed cap 105. A restricted passage 120 in the web 102 provides the fluid connection between the two cylinders. The piston 106 is operated by turning a member 109 having a helical cam surface engaging a corresponding surface on the end of the piston which is prevented from rotation by a pin 107. The member 109 has an operating arm 111 connected by a rod 112 to the pedal. A pipe 122 extends to the pressure regulator. According to the first Provisional Specification, the pressure regulator comprises a bellows with tubular extensions at both ends extending through holes in the opposite ends of the casing and connected respectively to brake adjusting apparatus as described in Specification 497,227, and to a pressure indicator, the pressure being regulated by a screwed cap on the casing. According to the second Provisional Specification a brake system such as described with reference to Fig. 8 is suitable for use with brake devices such as described in Specification 497,227, balance between the several brakes being obtained by adjusting the operating arms.