GB1370768A - Cylinder and piston unit and control device therefor - Google Patents

Abstract

1370768 Valves ROBERT BOSCH GmbH 28 March 1973 14813/73 Heading F2V A diaphragm valve 5 (Fig. 1) for controlling the piston/cylinder 11 in response to a changeover valve 7 comprises a set of plates and a diaphragm valve member connected to the housing of the cylinder at one end thereof (Fig. 3). Control lines 8 and 9 enter the housing 11 and form passages (18) (Fig. 6, not shown) and 17 respectively. These passages terminate in respective grooves 27 and 28 which are formed in a valve plate 23. The valve plate further comprises a set of four apertures 29, 30, 31 and 32 (Fig. 5) which receive portions of the diaphragm valve member 46. Fluid pressure applied to groove 27 biases the lower half of the diaphragm to a closed position against a guide plate 53; fluid pressure applied to the groove 28 biases the upper half of the diaphragm to the closed position. The fluid in line 4 (Fig. 1) flows to an inlet 19 (Fig. 3) whereafter it passes to the guide plate 53 through an aperture 54 (Fig. 4). The guide plate 53 comprises four apertures 56, 57, 58 and 59 having respective sets of apertures 60, 61, 62, 63 surrounding them and having communication between the aperture and its respective set being controlled by the diaphragm 46. In addition, the sets and apertures themselves are connected by grooves as shown in Fig. 4 which are formed in the face of the plate 53 remote from the diaphragm. Fluid from aperture 54 flows to the set of apertures 60 and 62. The relief passage 20 (Fig. 1) enters the housing and passes through to the plate 53 at aperture 55. The set of apertures 61 communicates with openings (74) and (75) (Fig. 2, not shown) and aperture 58 with opening 78 (Fig. 3) these openings allowing controlled fluid to enter or leave the working chamber 13 (Fig. 1). A passage 45 allows working fluid to enter or leave the working chamber 14. Operation.-When the change-over valve 7 is in the alternative position shown to Fig. 1 fluid flows through line 8 to passage (18) whilst the passage 17 is connected to the relief part 10. From passage (18) control fluid flows into chambers 31 and 32 to cause the diaphragm to close apertures 58 and 59. Thus working chamber 13 is shut off from inflowing fluid and working chamber 14 is isolated from the relief passage 55. In addition the apertures 56, 57 are opened since the line 8 is relieved, and fluid flows from aperture 54 to aperture 56 and thence to working chamber 14. Working chamber 13 is relieved via the set of apertures 61, groove 68 and aperture 55. When the change-over valve 7 is moved to its other position the apertures 56, 57 are closed and 58, 59 are opened so that working chamber 13 is supplied with fluid and working chamber 14 is relieved.