Patent GB-497415-A (GB)
Title: Air pressure regulating apparatus
IPC: B60S5/04
Filed: 1937-03-12
Abstract: 497,415. Pressure - regulating valves. BEATH, L. B. March 12, 1937, No. 7353. Void. Convention date, March 12, 1936. [Class 135] Apparatus for inflating tyres and the like in which a valve 8 in the air line is alternately opened and closed until a predetermined pressure is attained on its discharge side, comprises two spring - loaded levers 72, 86 movable in opposite directions by means of diaphragms 57, 20 respectively, one of the diaphragms, 20, being continuously and the other 57 intermittently subject to the outlet pressure of the valve S and the loading spring of one of the levers 86 being manually adjustable by means which also operate an indicator 96 showing the predetermined pressure of the tyre, whilst the other lever 72 operates an audible signalling device 84 each time it moves to allow the valve to close. As shown, a spring-closed lift valve 8 in a casing 1 mounted on the frame A, A<1> is operated by a push rod 13 linked to the lever 72 which is pivoted on a bracket 73 on the diaphragm casing 55. The loading spring 77 of the lever 72 is anchored on a bracket 78. The outlet 2 of the valve is connected to a conduit leading to the tyre, which conduit has a branch communicating with the diaphragm chamber 19 so that the pressure therein opposes the mechanical pressure of the lever 86, due to its spring 88, acting on the diaphragm through the pin 28. The diaphragm 20 is connected to a ported plunger 35, the reduced end of which slides through a bore 33, Fig. 7, into a recess 32 formed in an extension 29 of the chamber 19. A coil spring 38 tends to hold the plunger 35 away from a rubber or like seat 45 in a member 41 movable with clearance in the recess 32. A valve 50 clamped on the rearward extension 46 of the member 41 controls ports 54 open to the atmosphere. The valve 50 moves in a larger recess 31 and is closed by a spring 62 when the plunger moves away from the seat 45. The spring 62 is located in a recess in a nozzle-like part 60 of the casing 55. Passages 65 connect the recess 61 and the diaphragm chamber 56. The annular passage 42, Fig. 7, communicates with the recess 61 by means of ports 49, an annular recess 47, and ports 52. The adjusting means for the spring 88 comprise a threaded r d 90 supported by bearings 9 , 2a, Fig. 2, and longitudinally movable by a threaded sleeve 93 operated by a handle 94. One end of the spring 88 is connected to a bracket 9 clamped on the rod 90. Initial adjustment of the spring 88 is performed by a threaded eye-bolt 89a. The indicator 96 which moves over a scale 95 is operatively connected to the bracket 89 by a shaft 103 adjustably carrying a rack 101 maintained in mesh with a pinion on the indicator shaft 97 by a spring-loaded roller 107. The audible signalling device comprises a gong 84 having a striker 83 operated through a spring plunger 81 and a bell-crank 79 which is connected to the lever 72. In operation, the crank is turned until the indicator 96 shows the predetermined pressure and the usual chuck on the air line is applied to the tyre valve stem. As the pressure in the tyre and hence in the air line and the chamber 19 is then below the predetermined value, the mechanical pressure of the lever 86 closes the plunger 35 on the seat 45, opens the valve 50 and vents the chamber 56 so that the parts occupy the positions shown in Fig. 1 in which the spring 77 is holding the valve 8 open. The passage 39 in the plunger 35 is also cut off by the coil spring 38 which acts as a valve. As the pressure rises in the chamber 19, the plunger 35 moves first to allow the valve 50 to close the ports 54 and thereafter to leave the seat 45 so that air can now pass through the plunger and the passages 42, 49, 47, 52, 61, 65 into the chamber 56 where it operates the diaphragm 57, so that the lever 72 moves to allow the valve S to close and also operates the gong 84. The subsequent fall in pressure in the chamber 19 again causes the plunger to be moved against the seat 45 and the operation of opening the valve is repeated. This cycle of operation is repeated until the pressure in the tyre and hence in the chamber 19 reaches the desired valve at which it balances the force of the lever 86 so that the plunger 35 remains unseated and the valve 8 closed.