GB1340450A - Fastener applying device - Google Patents

Abstract

1340450 Fastener driving tool SENCO PRODUCTS Inc 28 March 1972 [25 Aug 1971] 14476/72 Heading B4C A pneumatically operated fastener driving tool comprises means whereby a fastener driving piston can perform a single driving stroke and a single return stroke each time the tool is actuated by depression of a trigger. A movable valve stem 70 in its non-actuated position coacts with a movable valve sleeve 58 to permit passage of air in reservoir 16 via ports 68, 69 and 56 and bore 28 to the upper surface of a main valve 26 so that the main valve is maintained in contact with the upper end of cylinder 18, thus venting the cylinder space above the piston. Depression of the trigger 32 moves the stem relative to the sleeve into a position in which sealing ring 74 engages bore 64 to prevent supply of air to the main valve upper surface and ring 76 no longer sealingly engages the bore 64. Thus the space above the main valve is vented via bore 28, ports 56, 69 and space 66 to atmosphere. The air in the reservoir causes the main valve to move away from the cylinder and air from the reservoir drives the piston 20 on a working stroke. At the end of the working stroke, air from the reservoir passes via bores 34 into a return reservoir 36 and also into chamber 44 via passage 38 and a check valve 40. Air supplied to the chamber 44 causes the sleeve to be moved to the position of Fig. 5 in which air from the reservoir 16 can again pass to the space above the main valve 26. The main valve now returns to its initial position and the cylinder space above the piston is vented. Air within reservoir 36.effects return of the piston. Flats on driver 22 permit venting of the cylinder space below the piston and reservoir 36 via the fastener drive channel. The sleeve 58 is maintained in the position of Fig. 5 until the trigger is released, thus permitting venting of the space 44 via space 48a and grooves 104. A valve body slidably mounted in a bore intersecting the passage 38 may include, besides the check valve, a solid blocking portion and a portion provided with a through bore. With the passage blocked, the piston will only be moved on a driving stroke upon each depression of the trigger, return being effected upon trigger release, and with the through bore coincident with the passage, the tool will continue to recycle if the trigger is retained depressed.