GB1386704A - Remote valve for pneumatic tool - Google Patents

Abstract

1386704 Fastener driving tools SENCO PRODUCTS Inc 25 Jan 1973 [17 April 1972] 3845/73 Heading B4C [Also in Division F2] A pilot valve device for operating the main valve of a fastener tool (see Specification 1,386,703) comprises an oscillating stem 94 moved under differential fluid pressure, a manually operated stem 86 controlling movement of the stem 94, and a reciprocable valve housing 34 which enables the main valve to cyclically open and close on a single movement of the manually operated stem 86. In operation pressure fluid passes from the general space 16 through ports 54 in the housing 34 upwardly and out via ports 56 and thence to passage 112 which connects the pilot valve device with the main valve. The fluid also passes downwardly in passage 110 and acts on the lower face of the oscillating stem 94. The outer part of the underside of stem 94 is connected to atmosphere via passages 50, 84 and 28. Thus the stem 94 is held in its lowermost position by fluid pressure. When the stem 86 is actuated manually pressure fluid is applied to the outer underside of stem 94 via passages 78, 84 and 50 which biases the stem 94 upwardly (Fig. 3, not shown). In this position the passage 112 is disconnected from the pressure fluid by an 0-ring 104b and connected to atmosphere via passages 52, 48. The main valve is thereby actuated accordingly. A passage 114 is provided to enable the main valve to cycle. Where the main valve operates a piston in a cylinder the passage 114 is connected to a working chamber. When the piston reaches the end of its working stroke the pressure in passage 114 rises and so raises the valve housing 34 (Fig. 4). Once again pressure fluid flows into passage 112 to change the position of the main valve which in turn lowers the pressure in passage 114 and so on.