GB1156159A - Improvements in or for a Pneumatically Actuated Fastener Driving Tool - Google Patents

Abstract

1,156,159. Nailing and stapling tools. D. HAUBOLD, [trading as DIETER HAUBOLD INDUSTRIELLE NAGELGERATE], 1 Dec., 1966 [1 Dec., 1965], No. 53893/66. Heading B4C. A pneumatically-actuated tool for driving fasteners, such as staples or nails, comprises a driving piston 7 reciprocable in a cylinder 4 mounted in a housing 1, and a control valve assembly including a first valve portion 13 adapted to control the air into the cylinder for driving the piston and a second valve portion 19 for controlling the exhaust air connected to a flexible diaphragm 23. The first valve 13 is slidable in a cylinder 14 and is adapted to be acted upon by the diaphragm 23. In the position shown compressed air is fed into a supply reservoir 2 and flows via a triggeractuated valve 36 and passages 34, 32, into a chamber 31 so as to act on the diaphragm and maintain the first valve closed and the exhaust valve open. Upon operating the trigger, the valve 36 is moved so as to exhaust the chamber 31 and thereby allow the valve 13 to be opened by air pressure acting on a shoulder 40; the exhaust valve is also then closed by the effect of the pre-stressed shape of the diaphragm. Air then acts on top of the driving piston in order to effect a working stroke. Upon release of the trigger, the valves take up the position shown again, the air above the piston being exhausted via valve 19 and ports 18, 26. In a modification, the outer edge of the diaphragm is secured to an auxiliary piston connected to the valve portion 13, instead of being rigidly fixed to the housing as shown. A magnet 30 is provided for retaining the driving piston in its raised position.