Patent GB-1494012-A (GB)
Title: Machine for automatically driving threaded fasteners
Inventor: DIXON PAUL H
IPC: B25B23/04
Filed: 1975-10-17
Abstract: 1494012 Fastener feeding and driving machines B DIXON 17 Oct 1975 [25 Oct 1974] 42743/75 Heading B3N A fastener driving and feeding machine 30 comprises a power-operated fastener driving gun 35 including a rotated driver 39, Fig. 2, and a tubular member or "finder" 40 slidably mounted and normally extended relative to the driver and having an end portion sized to receive a fastener, e.g. screw 31. A transfer mechanism 50, Fig. 3, delivers the fastener to a driving position in which the fastener is in line with the end portion of the finder 40 and means, linkage 103, Fig. 6, operated by the transfer mechanism retracts the finder sufficiently, as the fastener is delivered, so that the fastener is located under the finder, and then allows the finder to extend and receive the fastener. As shown in Figs. 2, 3 and 5, the transfer mechanism 50 includes a pair of jaws 63 pivoted at 81, 83 to a carrier 76 which is advanced and returned, by a piston-rod 94 of cylinder 93, towards and away from the finder, the mechanism being guided along different advance and return paths by follower rollers 85, 86 following camming slots 87, 88 in housing side plates 53 54. The jaws grip the fastener initially by means of a horseshoe shaped spring 129 which embraces the jaws when required and which is controlled by links 134 engaging lugs 140, 144 on the housing, and finally by abutments 143 on the housing. The means 103 for retracting the finder 40 comprises a bell crank lever 111 actuated by means of the transfer mechanism and which acts to raise the finder 40 via lift bar 105 and ring 41 on the finder. The finder returns to its extended position under the bias of spring 45, Fig. 7. In operation, a screw is held in the driving position, Fig. 2, by the jaws 63 and finder 40 and the tool and fastener are pressed against a workpiece by the operator. Finder 40 retracts against spring 45, and a valve ball 116 in bell crank lever 111, and normally held down by lift bar 105, is released and is unseated by air pressure in line 124 which passes a signal to cause actuation of cylinder 93 to return the jaws 63 to a pick-up station (64), Fig. 13 (not shown), and away from abutments 143, so allowing the jaws to release the fastener. On reaching station (64), spring 129 engages the jaws and closes them, and a probe 126, Fig. 2 connected to piston-rod 94 closes an air line (127, Fig. 11, not shown) which signals the feeding unit 70 to blow another fastener down tube 66 and into the closed jaws. A timer (not shown) delays further movement of cylinder 93 to allow the fastener to travel the full distance along tube 66. After the first fastener has been driven home by driver 39 and the gun is released from the workpiece, finder 40 extends and ring 41 acts on lift bar 105 to reseat valve ball 116. Cylinder 93 is extended and jaws 63 advance to delivery station 65. On their way, one of rollers 86 pivots the bell crane lever 111 clockwise to slightly lift bar 105 and finder 40, as mentioned previously, to allow the fastener to be correctly positioned. Valve ball 116 remains seated even when follower roller 86 releases the bell crank lever and the finder extends to engage the screw. The cycle is then repeated. The feeding unit 70, Figs. 1, 20 has a rotary drum 161 which feeds fasteners along a track 163 to a positioning mechanism 164 comprising linkage 166, operated by cylinder 170, and gripping fingers 164. Fasteners are taken from the track and positioned under a reciprocable head 174 which transports them to the end of tube 66 and blows them down it under control of the gun. In an alternative embodiment for use with small fasteners, the fasteners are held by a flexible cartridge 210, Fig. 24, which shuttles between the head 174-along tube 66-and transfer mechanism 50. This prevents end-overend turning of the fasteners in tube 66.