USRE110E - Improvement in machinery for cutting the threads of pointed screws - Google Patents

Description

. of the thread on the UNITED i STATES` THOMAS J. sLoAN, or NEW YORK, Nl Y.

. IMPROVEMENT IN Miam-'MERY Fon' currm THE THREADS or Pomrn scREM/s.

Specification forming part of Letters Patent No.' 4,964, dated November 24, 184() l Reissue No. l0, dated March 8, 1848. I

To all whom t may concern.-

Be it known that I, THOMAS J. SLoAN, of the city, county,'a.nd State of New York, have invented new 'and'nseful Improvements in thel v.Machine for Threading Screws; and I dohereby declare that lthe following isa full, clear, and exact description of the principle or character which distinguishes them from all other 1-things before known,

making, constructing,l

and of the manner of and using the same,l reference being had to the accompanying drawings,'making part of this specication,

' in whichf A Figure 1 isauelevation; Fig. 2, a plan; Fig.; 3, an elevation of the right-hand end; Fig. 4, an elevation of the lett-hand end, Fig.' 45, 'a- [longitudinal 'section `whichholds the blank;l Fig. 6'a view of the gearing, and Fig. 7 a separate "iew of, the

through .the A 'mandrel threading-cam.

.Thesame letters indicate like parts in all the figures.

The object of my invention isl to cut the threads of that kind of Wood-screws'invented by me, inY which the point is made conical,with the turns of the thread at'. equal distances apart along the body and point and gradually reduced iu depth and width'aloug the conical part and toward the apex thereof. yA s in this kind of screwsv the line of the thread has the -same'pitch at the .conicalpoint as it has along the'body,and the'thread is gradually reduced indepth and thickness toward the apex ofthe conical parl-,it becomes necessary to have the give` the pitch to the thread coincide with it atthe apex of vthe cone, and

thus form the thread withV allthe turns at `equal distances apart andv gradually'reduced in depth towardthe'apex of the conical poin t.A The vnature of this part ofniy invention therefore consists, `iir st, :in givingf .such Inotions .to the `cuttin'gedges which form the upper and under faces ofthe 'thread along` the l conical part relatively'to. the motionl of the blank that they shall approach theline of the splral thatforms a thread the turns of which are at' equal distances apart.

manner.

a mortise, i,

AIn the accoxnpauying'drawings; a represents a frame properly adapted' to the purpose, but

v which may be varied atv pleasure, and b a spindle or l'n'andrel that carries the screwblank c to be threaded. This spindle runs in appropriate boxes inthe two standards d d of the frame, and may be driven by a b eltfrom any iirst mover passing around ay pulley, e, (Shown by dotted lines',) or in any other desired It is made hollow from end to end to receive a rod, f, that holds the screw-blank against the'inner shoulder, g,'of the forward end of the spindle, the hole being there eon.- tracted to the size of thc shank of the screw,

that it may be'gripped between this 'shoulder Vand the end of the rod f by a wedge-key, h, that passes through a hole in the spindle and rod. Y The screw-blank is introduced through in the head of the spindle and the shank pushed through the central hole by the rod f until the under side of the head. is brought against the shoulder g, where it is gripped, the rod being provid ed with aiillet or screw-driver to t into the nick in the head of the blank. 1

The chasing-tools or cutters j j are inserted and fastened by temper-screws k each in a sliding head, l, by means of which the chasers can be made to move vtoward the axis of the blank to cut in and to move from end to end -to determine the pitch of the thread. The rear and front \euds of the sliding heads rest ou Ways m m of the frame, that they may slide freely iu any horizontal direction, andeaeh Ahead is provided with an arm, n, so formed that the'y all lie one above another, although the heads are all onthe same plane. The said arms are jointed to a slide, o, each on a separate pin .pi freely, so that when the slide o moves itc'arries with it all `the heads with the chasers in 'theln to determine Athe pitch of the thread.

The pitch of -the thread'is determined by a cam, q, the periphery of Ywhich acts ou the slide ,o (a roller, r, being linterposed to avoid friction) to move the chasers in the direction fromthe head towardthe point of ,the blank.' The chasers, as they move from end to end ol'- theblank,` are pushed toward the axis of the blank to cut thethread by the curved face of a mold, s, attached 'to one of the Ways, m, by means of screws t 't t, that pass through elonthat'they may vibrate thereongated holes to admit of adjustment. y The rear end of the chaser-heads are provided each with an adjustable piece, u, secured in place by a A set-screw, v, that the point of each chaser may be adjusted that each may cut deeper than the preceding, and' to adapt the machine to the cutting of screws of di'erent sizes, and these adjustable pieces are rounded o or otherwise adapted to slide against the face of the mold s, which is so formed that from the point-1 to 2 itis straight, that the chaser may gradually approach the point where they are to be movedY toward the axis of the blank. From 2 to 3 the mold is curved, to push each chaser in turn toward the blank to commence the thread. From 3 to 4 it runs parallel with the axis of the blank, or slightly inclined thereto, to chase the thread along the. body of the stem; and

y from 4 to 5 it again curves in, to make the chasers. one by one approach the. axis of the blank to form the conical point of the screw, and as it is desirable' that the conical point should gradually run into the'line of the body this part of the mold is made with a gentle curve. In this way the whole series of chasers are made to act on the blank in succession to cut the thread, each in succession cutting deeper, so that the thread is completed by one motion of the series.

The motion of the chasers to-determine the pitch of the thread is communicated tothe chaser, as stated above, by thel cam q on the shalt w, which receives motion lfrom' the spindle or mandrel b by a wormLv, and cogwheel y. r- Y The cam q is divided into six parts-one for each chascr. The irst part, 1 operates the slide o to carry the cher along the body o f the blank by a regular motion, to give the pitch to the thread, and as it passes along the conil point'this progressive motion 'is' slightly retarded by the depression 8 in the face of the cani. The second division, 2., then begins to act on the slide to carry the second chaser along the body of the blank..and at the end of this division there is a slight swell, g', from the general lineof the cam, to accelerate the motion of the chaser in forming the thread along the conicalpont of the screw. InJ like mannereach division of the cam from 1 to 6 Vhais'either a depression or aswell alternating,

sol that one-chaser is' accelerated, the next retarded, and so on to the end, to cut away the upper and under surfaces of the thread on the conical part or point, and thus gradually reduce the depth of the thread, and at the same time form the pitch-line of all the turns of the equal distances apart. So Vsoon as division 0f .the Cam l z :uw: the muet 1; the -slide o is pushed back by a spring, a', to

recommence the operation on another blank, which must be substituted for the one that has ,been threaded. 0n the return motion'of the slide the. chasers pushed back the 'blank by springs b', attachedto the slide and bearing thearm of each head. Only one of these springs is shown in the drawings,

the others being applied in the same way.

The above represents one of the modes in which the priucipleof my invention can bev f applied; but it will be apparenty on examination that this principle is susceptible of a variety of modifications-as, for instance, the

desired form can be given to the threadwith one chaser or cutter only by giving to it, as it reaches the conical point, alternately-an accelerated and then a retarded motion, that at one cut it may move faster as it along the conical point, and at the next slower, and so onnntil the' thread is completed. By thus accelerating and retarding the motion the two faces of the chaser gradually approach theV pitchline'of the thread toward the apex of the conical point, and thus reduce-.the depth of the thread, and finally lose it in the apex of the conical core; or two chasers maybe employed, one having an accelerated and the other a retarded motion when passing along the conical point, the spindle having a regular motion; or the two 'chasers may remain stationary while cutting the thread on the cyliu-o drical part or bodyof, the stem, the blank be' ing moved longitudinally to give the pitch to the thread, and then, as the conical part or point passes the chasers, the cutters or chasers' gradually t'o-move in opposite directions toward thepitchline of the thread; or asingle fixed chascr may be used'by giving f a longitudinal motion to the blank for deterare caused mining the pitch of the thread, and alternately accelerating andretarding this motion to form the' thread onfthevconical part, as above described.

The form of cam described above for giving the alternate accelerated and retarded motions to the chasers, together with the mode of gripping the blank and operating the chaserheads,'may b evariously modified without l. changing the principle of my invention, the being simplyV described and represented to show one of the modes of applying the said princi le what to. secure by Lettl''lwnt, i-

Giving to the cutting-edges which form the upper and under surfaces of the thread on the conical part of the screw a motionor motions or position relatively to the motion of the J blank on which `the thread is t0 be cut, so that the shall gradually approach the pitchline o f e thread, the turns ofwhich are at equal distances apart, and thereby gradually reduce the depth of the thread as it applfOllcS the apex of the cone,^substant1ally Y 11s-described.. f- Trios. .I .sLoAra Witnesses; Arxmrlonrnn BROWNE,

1 claim as my invention, yand desire.

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