Tool for inserting wire coil screw thread inserts in bores

摘要

842,257. Inserting screws. HELI-COIL CORPORATION. Jan. 2, 1959 [July 8, 1958], No. 146/59. Class 83 (3). A device for inserting a helical wire-thread 100 in the bore of work W comprises a tubular member 15 having a lateral recess 60 through which the wire coils are fed into the path of a mandrel 30 guided in the member 15, a helical shoulder 33 forming a step 35 adjacent the lower end of the mandrel, and means 43, 44 to rotate the mandrel in the direction of the coil winding as it is moved downwardly, so that the step 35 will engage the end of the coil. The mandrel is fed down by a press (not shown), acting on a housing 38 having a bearing 39 for the rotatable mandrel, a spring-ring 41 preventing escape of the mandrel from the housing. Rotation of the mandrel is by a pin 43 which traverses a helical groove or a slot 44 in a sleeve 16 fixed within housing 15 by screws 16SP1/SP. Slot 44 may open out at its lower end 45, Fig. 14, so that the lower edge 44 of the slot ceases to rotate the mandrel as this drives the coil out of the end 23, 24 of member 30 and into the work. A feed-shoot 46 for the coils enters a tube 49 controlled by an escapement lever 64 influenced by a spring- pressed plunger 69 to support the column of coils. Release of the escapement is by a face 74 on a feed-slide 52, which is operated by duplex levers 92 connected by springs 90, 91 to a rod 86 attached to duplex levers 75. These are pivoted to the frame 10 of the device, and bear at 79 in a further guide-sleeve 81 for the mandrel. A spring-pressed detent 82 influences levers 75 towards their extreme positions, and stopscrews 62, 63 limit movement of slide 52. One side of the feed-opening in tubular member 15 is closed by a spring-pressed plug 56, and one side 24 of the end of the member is adjustable, being loaded by a spring-pressed ball 25. Towards the end of a coil-inserting stroke, housing 38 strikes and carries downwardly the sleeve 81, which effects withdrawal of slide 52 to the position depicted in Fig. 3, in which it receives the coil previously deposited on its top surface. Withdrawal of slide 52 also permits escapement 64 to be moved by pin 69 to its closed position. Towards the end of the withdrawal stroke, a shoulder 37 (Fig. 10, not shown), on the mandrel strikes and raises the sleeve 81, thus delivering another coil through the feed-opening 60 and releasing a further coil, which falls on to the slide, which has a bifurcated end 55 to pass the mandrel upon withdrawal of the slide. In a modification, Fig. 15, the direction of the helical slot 144 in sleeve 116 is reversed towards its lower end, which is enlarged at 147. Thus, as the coil leaves the end 23, 24 of tubular member 15 to enter the work, its direction of rotation is reversed in order to effect a reduction in its outer diameter. The enlargement 147 permits disengagement of the step 35 from the end of the coil before pin 143 engages the top edge 146 of the slot and rotates the mandrel in the opposite direction during its withdrawal.