Patent GB-1176835-A (GB)
Title: Improvements in or relating to Fastener Inserting Tools.
IPC: B21J15/04
Filed: 1967-03-14
Abstract: 1,176,835. Blind eyeletting. GEORGE TUCKER EYELET CO. Ltd. 14 March, 1967 [15 March, 1966], No. 11788/67. Heading B3U: A blind-eyeletting tool adapted for use in spin setting the tail end of an eyelet barrel, comprising a housing having a nose-piece adapted to engage the head flange of an eyelet inserted through a hole in a workpiece, a mandrel support mounted for rotation within the housing and for axial movement therealong relative to the nose-piece, means for rotating the mandrel support, a control member mounted on the housing and movable relative thereto by the operator, and means responsive to movement of the control member to actuate said means for rotating the mandrel support and to cause the mandrel support to move axially rearwardly of the nose-piece, whereby when a mandrel with a hooked tip is mounted on the mandrel support and projects through an eyelet accommodated in a hole in a workpiece, movement of the control member causes the tip to spin and press against the tail end of the eyelet barrel. The housing 10 contains an electric motor which drives a shaft 20 through reduction gearing. A pistol grip 12 contains a sliding trigger 14 which operates a motor-control switch and is also connected by a force-increasing linkage to the mandrel support to provide the axial component of the rivet-setting movement. A cylinder 24 screws on to a threaded nose on the housing and has a tapped bore at its front end which receives a hollow nosepiece 70 which carries an anvil 72 which engages the head of the eyelet E. The rivetsetting mandrel 18 passes through the nosepiece and screws into a hub 44 which is a pressfit in the inner race of a ball-bearing 40. The outer race of the bearing 40 is a clearance fit in the cylinder and is engaged by a cup-washer 36 which is a slide fit in the cylinder and is biased forwardly by a spring 34 which abuts the housing. The forward position of the hub is determined by an annular washer 46 secured to the hub and which abuts a shoulder formed in the housing. At the rear end of the hub are dog-clutch teeth which co-operate with similar teeth 26 on the shaft 20. A brass sleeve 30 secured to the hub extends beyond the clutch teeth and is longitudinally slit at 32, so that it can frictionally engage the shaft 20. A ring- shaped lever 62 is loosely pivoted on a pin 64 and at its opposite side is acted on by a lug 59 on a link 58 attached to the trigger 14. The rear face of the lever is shaped so that it engages the inner race of the bearing 40 only at diametrally opposite points situated midway between the pivot 64 and the lug 59, so that the force exerted manually by the operator, is doubled. A projection 54 on the washer 46 engages a stop face in the cylinder so that the hub 44 always stops in the same angular position. Setting mandrel.-One side 78 of the mandrel, Fig. 3, slopes at 12 degrees to its centre-line and at the opposite side is an overhanging hook which has a convexly rounded leading edge 80 and a trailing edge 82, relieved to clear the rim being formed on the eyelet. Operation.-Finger pressure on the trigger first switches on the motor and then draws the hub 44 rearwards so that the dog-clutch teeth engage. As the mandrel rotates, further movement of the trigger draws the hub and mandrel rearwards so that the edge 80 spins over the rivet shank. When the trigger is released the spring 34 disengages the clutch teeth, but the shaft 20 continues to drive the hub 44 by friction through the sleeve 30 until the projection 54 engages the stop-face and the hub 44 stops in the desired position, before the motor comes to rest.