SE7412468L - - Google Patents

Abstract

1487098 Fastener driving tool J E SMITH and J D CUNNINGHAM 2 Oct 1974 [4 Oct 1973] 42685/74 Heading B4C A tool for applying impact forces to an object 62 comprises a ram 12 mounted for movement along a drive path toward and away from object 12, a flywheel 16 located on one side of the ram, actuating means 32 for bringing the flywheel and ram into driving engagement and a rotary means 14 located on the opposite side of the ram to the flywheel to support the ram. Preferably object 62 is a nail, staple or rivet to be driven into a workpiece. Alternatively the ram may strike the workpiece. Preferably rotary means 14 is a second flywheel journalled in fixed bearings whilst flywheel 16 and its electric motor 44M are joumalled in a movable bearing 34 comprising arms 86 pivoted about pin 88, an embodiment in which both flywheels are moved into contact with ram 12 being specified without exemplification. The actuating means 32 comprises a pair of rearwardly extending parallel arms 104 attached to a nosepiece 26. On pressing the tool against a workpiece whilst pressing trigger 54 nosepiece 26 and arms 104 move rearwards against the bias of springs 36. Ears 112 of pivoted arms 86 are received in notches 114 in arms 104. Hence rearward movement of arms 104 swings the flywheel 16 so that ram 12 is driven forwards by the two flywheels. The ram is guided in grooves 100 in arms 104, the grooves being wider than the ram to allow it to be pressed against fixed flywheel 14. The length of the ram is such that it is no longer in contact with the flywheels when it strikes resilient cushion 24 after having driven nail 62. When the tool is removed from the workpiece springs 36 pull arms 104 forwards to move flywheel 16 away from flywheel 14 and allow spring 30 to pull ram 12 back ready to drive another nail. Stop 108 limits forward movement of arms 104. On pulling trigger 54 switch 130 energizes electric motors 44F, 44M and link 140 raises stop 138 so that its forwardly projecting abutment 142 is no longer aligned with lower arm 104. Hence arms 104 can be moved rearwardly to actuate ram 12 provided trigger 54 is pulled whilst the tool is pressed against the workpiece. The speed of the electric motors is adjusted by switch 20 to control the driving power of the ram. Magazine.-Nails 62 linked by paper tapes 156 to form a belt are urged by spring driven follower 152 so that the leading nail contacts stop 158 in position to be driven by nose 122 of ram 12.