GB291727A - Improvements in machine for screw-threading nut blanks and the like - Google Patents

Abstract

291,727. Automatic Nut-Thread Corporation, (Assignees of Safford, L. A.). June 6, 1927, [Convention date]. Tapping; blanks and finished arficles, transferring; stop devices.-In an automatic nuttapping machine, nut blanks are fed singly from a shoot to a registering device which places them in a position suitable for feeding to a rotary chuck surrounding a stationary tap along which the threaded nuts are traversed by the threads of the tap. The chuck comprises two interchangeable jaws 21, Figs. 3 and 5, keyed within a hollow spindle 12 rotated continuously by gearing 20, intermediate shaft 17, change speed gearing 18 and a belt pulley 15, and abuts against a sleeve 24 rotated with the spindle and surrounding the straight portion of the tap 27. The shank of the tap is curved, its rear end 28 projecting into a bush 29, and it is maintained in position by the finished nuts 11 engaging the sleeve 24 and the bush 29. The latter is removably held in a block 31, Fig. 1, so that it may be exchanged readily for one of different size, by a hinged cover 32 and is adjustable axially of the tap to suit different sized nuts by bolts 36 and slots 35. The nut blanks are removed singly from the lower end of a vertical shoot 41 by an axially reciprocated sleeve 67, Figs. 3 and 5, and are transferred to a registering device comprising a bush 51 shaped internally to fit the nuts and operated so that it is stationary with its sides in a position suitable for receiving a nut when the latter is leaving the shoot whereas it is rotated in unisor with the chuck when the nut is being transferred from the bush to the chuck. For this purpose the bush 51 is keyed at 52 in a ring 46 rotatable within a fixed bearing 45 on the machine frame and adapted to be coupled to the chuck by a sliding key 53 and clutch teeth 54 on the chuck-spindle. The key is normally pressed into engagement with the teeth by a spring 55 but may be retracted by a radial plunger 59 having a wedge-shaped end engaging an inclined shoulder 57 on the key. The plunger is reciprocated by a yoke 61, Figs. 1 and 5, carried by a rod 60 which is oscillated by a cam-block 63 on the rod and a roller 65 movable with the blank-transferring sleeve 67. In operation, during the backward movement of the sleeve 67 the cam-block 63 is released and a spring oscillates the rod 60 to withdraw the key 53 from the clutch teeth and bring the bush 51 to rest with its internal sides in a position suitable to receive a new blank. When the latter is completely within the bush the latter is coupled to the rotating chuck, the clutch teeth being so arranged that the sides of the chuck are in a position suitable for receiving the blank which is pushed on to the tap by the sleeve 67. Means are provided for stopping the feed of nuts should undue resistance be encountered and comprise a hollow shaft 68, Figs. 3 and 5, to which the sleeve 67 is secured, slidable within a second sleeve 77 slidable within a fixed bearing 10. A spring 79 causes a yielding feed pressure to be exerted on the sleeve 67 by the sleeve 77, the latter being reciprocated by a cross-head 85, adjustable by nuts 84 and connected by links 86 and arms 87, Fig. 1, with a shaft 88 oscillated bv a continuously rotating cam 90 acting against springs 97 and driven by change gearing 93 and worm gearing from the intermediate shaft 17. A spring pressed plunger 101, Fig. 3, is slidable radially in the shaft 68 and normally rests against the inner periphery of the sleeve 79. Should the latter slide relatively to the sleeve 67, however, due to an obstruction being encountered, the plunger will come under a movable tongue 98 in the sleeve 77 and raise a shouldar 100 thereon into the path of a stop plate 104 so that when the sleeve tends to return its complete retraction is prevented and the cam arm 89 leaves the cam 90. Reciprocation of the sleeves thereupon ceases until the obstruction has been removed and the tongue 98 has been depressed. The blanks are supplied singly to the top of the shoot from loose assemblage in a bin 37, Fig. 1, by automatic mechanism 39, and descend by gravity in a continuous line, the bottom blank resting on a stop 43, Fig. 3. The front and back plates of the shoot are adjustable by washers on the securing bolts to accommodate blanks of different thicknesses. Cuttings, removing; lubricating and conling cutting tools and work.-A shaft 73, driven by a chain 74 from the intermediate shaft 17. Fig. 3, rotates a pump 69 which draws coolant through a pipe 70 and supplies it by a flexible pipe 71 to an elbow 72 on the end of the shaft 68 through which it passes to the tap 27 to lubricate the latter and wash away cuttings.