GB1381682A - Fastener driving device - Google Patents

Abstract

1381682 Fastener driving tools TEXTRON Inc 1 May 1973 [5 May 1972] 20596/73 Heading B4C A fastener driving tool is operated by fluid pressure (compressed air), under the control of an actuating member 20 movable from an inoperable position, Fig. 2, into an operative position, Fig. 5, enabling means 36 being provided to enable movement of (1) the trigger 30 into its operative position when the work contact responsive member 26 is in its inoperative position without movement of the actuating member (2) the trigger into its operative position when the work contact responsive member is in its operative position to effect movement of the actuating member into its operative position, and (3) the work contact responsive member into its operative position when the trigger is in its operative position without movement of the actuating member. As shown in Fig. 2, the trigger 30 is urged to its inoperative position about a pin 32 by a spring 34 and the enabling means 36 is urged anticlockwise about a pin 40 of the actuating member 20 to the limit of a stop 48 by a spring 46. The enabling means 36 consists of a U-shaped portion 38 carrying an arm 42 for contact by the work contact responsive member 26 and an arm 44 for co-operating with a pin 50 carried by the trigger. The member 26 is urged towards the workpiece by a spring 28. When, in Fig. 2, the trigger is pulled the pin 50 moves up to the upper position shown by the dotted line without engaging the arm 44 so that the actuating member 20 remains unmoved. If the trigger is held in this position and the member 26 is now lifted, the arm 44 swings beneath the pin 50 and the actuating member 20 still remains unmoved, Fig. 6 (not shown). When only the member 26 is lifted, the arm 44 swings above the pin 50 and again the actuating member 20 remains unmoved, Fig. 4 (not shown). Movement of the actuating member occurs only if the member 26 is lifted before the trigger is pulled, the pin 50 engaging and lifting the arm 44 as shown in Fig. 5. To prevent double firing due to rebound the pin 50 and arm 44 are arranged to disengage after a predetermined downward travel of the member 26, Fig. 7 (not shown). In a modification, Fig. 8 (not shown), double firing is prevented by making the arm (44) slightly longer such that after the member (26) has been moved to its inoperative position, movement of the trigger towards its inoperative position a predetermined distance will disengage the pin (50) and arm (44). In another modification, Fig. 9 (not shown), double firing is prevented by forshortening the arm (44) such that with the member (26) and the acutating member (20) moved into their operative positions, a movement of the trigger to the operative position causes disengagement of the pin (50) and arm (44). In a further modification, Figs. 10-13 (not shown), the enabling means (136) is pivoted about a pin (140) secured to the upper end of the work contact responsive member (126) and an arm (142) makes sliding contact with the lower end of the actuating member (120).