Patent GB-191505367-A (GB)
Title: Improvements in Machines for Manufacturing Twist-drills and other similarly Grooved Metal Articles.
Inventor: WILT ABRAM DARST
IPC: B23C3/32
Filed: 1915-04-09
Abstract: 5367. Wilt, A. D., [Assignee of Lees, E. J.]. April 11, 1914, [Convention date]. Lathes; milling.-Relates to machines of the type described in Specification 27,226/10, for making twist drills and like articles, and consists in improvements in details. Spindles.-The stock 5, Figs. 2 and 17, is fed by dogs 4 operated by a rod 18, actuated by the turret. Chucks. - The draw spindle 6 of the stock chuck is actuated through bell-cranks 8 from a cam 7<1> in a sleeve moved to close the chuck by springs (not shown) interposed between the sleeve and the bearing 2<1>. The chuck is opened prior to the feed, by a stop 18<a> on the bar 18, and is held open by the engagement of detents 155<c>, which are tripped on completion of the feed by the stop 18<1>. The chucks which receive the cut-off blanks are similarly constructed, but the cam-sleeves are actuated by contact with abutments at opposite ends of the travel of the work turret. In addition, a spring plunger loaded during the closing movement is tripped at the end of such movement to strike the sleeve a blow and secure proper closure. Centre rests.-The stock is supported during cutting-off by a bush 35, Fig. 17, and during the cutting of the grooves and lands, by bushes mounted between, adjustable with, and grooved to pass, the milling-cutters. Lubricating cutting-tools. - The cutters are lubricated, and the rests are kept free from chips, by oil supplied under pressure to the rear of the bushings. Blanks, transferring.-The blank to be cut off is engaged by a work turret chuck prior to cutting-off, and is ejected from the chuck, when machined, by a central rod in the chuck engaging an abutment at the close of the return stroke of the turret. The abutment is laterally deflected during indexing by the end of the ejector rod in the chuck arriving at the ejecting position, and is returned by a spring during forward feed ready for operation on the return. Blanks need not be cut off in the machine, but may be fed from a magazine. Cutting-off mechanism; cam-operated feedmotion.-The parting-tool is carried by a tool post (not shown) on a slide 27, Fig. 27, actuated by a rack 26, Fig. 2, engaged by the turret to rotate a sector 29 and cam 25 engaging a finger 31 on the slide. On conclusion of the feed, the cam passes the finger and spring plungers retract the slide, the parts being then in the position shown in Fig. 27. The finger 31 swings aside, to permit the return of the cam, sector, and rack by a spring during the return of the turret. The tool may only partly sever the blank, the turret chucks completing the severance by twisting off. Turrets; reversing-mechanism ; clutch-operating mechanism.-The turret 3, Fig. 14, is loose on the shaft 37 and non-rotating sleeve 38, but moves axially with this sleeve, as controlled by a nut 40 driven through the reversing- mechanism shown. Drive for the shaft 37 geared to the chuck spindles 92' is derived through the gearing 57, according to the pitch nf the grooves to be cut. The turret is indexed by a shaft 66 moved axially with the turret by the flanges of the pinion 75. A slide 79 is reciprocated with the shaft 66 and carries a spring plunger, Fig. 29, loaded during the advance of a turret and latched by a lever 85. At the end of the return, the lever is tripped by a stop 86, and a cam 82 on the plunger acts through a finger 81 to trip a stop 77, Fig. 30, from a notched disk on the shaft 66, to permit the shaft to make one revolution. Just prior to this release, the rearward movement of the shaft has brought a frictionally-mounted clutch part 65 into engagement with an axially-fixed rotating part 65<1>. A cam 67 throws the clutch 70 into the neutral position, and a cam 67<a> causes a further movement and effects the reverse, a spring bolt 88 maintaining the clutch in this position. A dog 71 and finger 72 trip the bolt for the reverse at the end of the forward stroke. The finger 81 is pivoted to yield during this stroke without tripping the stop. The turret carries a series of projections which pass between guides on the frame during the forward stroke to secure correct indexing. Taper work. - The grooving-cutters 130, Fig. 21, are mounted on heads angularly adjustable at 139 on swivelling heads 137, Fig. 20, having bushings 131<1>. The heads and bushings are connected to quadrants 131 meshing with a pinion On a sleeve 129 rotated by a worm 123, as controlled by an arm 122 engaging a cone 121 carried by the shaft 37 of the turret, to secure a decrease in the depth of the grooves towards the shank. A shoulder 121<a> moves the cutters clear of the work at the close of the cut, and a dished sleeve 133 closes them after the return, ready for the next cut. Copying-mechanism.-The cone 121 may be replaced by variously-shaped cams according to the movement of the cutters required. Depth of cut feed-motions.-The clearance cutters 158 are carried by spindles mounted in bushes 151 adjustable axially in heads 152 adjustable laterally and angularly upon tubular projections 131<1>, Fig. 40, by a pin-and-slot connexion to a flanged member 195, which carries one of the centre rests 200 and is correspondingly adjustable in the frame. The bushes 151 are controlled by pinions 154, Fig. 21, on shafts 154<1>, Fig. 34, carrying arms drawn together bv a spring 163, as limited by set-screws 162, to take off the cut, and separated by a bar 164 carried by the turret to restore and maintain the cut. Cutter-rotating mechanism. - The cutter spindles are rotated through spiral gearing 141 from shafts 138 meshing with a central wheel 126 and driven from the main shaft 42. Stop-motions.-In the event of excess movement of the turret, either forwardly or rearwardly, or of improper indexing, one of three dogs, carried by a reciprocable rod, is actuated to slide the rod which is connected to the means for stopping the machine.