US2196897A - Threading tool - Google Patents

Description

April 9, 1940. w. M. EMERY THREADING \TOOL Filed July 8, 1938 2 Sheets-Sheet 1 INVENTOR. CJz'Z/mm 777197267 WM G9 ATTORN 5 w, M. EMERY THREADING TOOL Filed July 8, 1938 2 Sheets -Shee't 2 INVENTOR. 7% 6m 67 M Q ATTOR 5.

BY llz'lliam Patented Apr. 9, 1940 UNITED," S ATES THREADING TOOL William M. Emery, Cleveland-Heights Ohio, ass signer to The Oster Manufacturing Company, v Cleveland, Ohio, a corporation of Ohio Application'July 8, 1938, Serial No. 218,109

' S CIaim's. (o1. 10 s9 This invention relates to threading tools for pipes, bolts and rods, and'is particularly directed towards a'hand' operated die stock tool with a geared drive to give an advantageous power ratio;

together with more efiicient feed arrangements, quick release, quick reset, and adjustment for over or under size threads'whichis not thrown out;

gagement of the tool with the work.

. In. general, my inventiongives to the user a more smoothly cutting tool, less fatiguing tonthe 20 operator, easier started, quicker in action, and

ated die stock, and primarily intended to be so used, it will be obvious that the invention is not I limited to manual operation, but is applicable either in all.-.particulars or in Various details to power stocks.

One of the advantages in connection with my gear drive is that the direction of rotation of the 36 handles is the same as the direction of the rotation of the dies upon the work, just'as in an ordinary stock, so that theoperator 'is not confused by any, opposite movement of parts. 7

To'the accomplishment of the. foregoing and 35' related ends, said invention, then, consists of the means hereinafter fully described and par ticularly pointed out in the claims.

The annexed drawings'and the following description set forth in detail certain mechanism 41 embodying my'invention, such disclosed means constituting, however, only some of various mechanical forms in which. the principle of my invention may be used.

In said annexed drawings 4 5 Fig.'1 is an axial central section through a preferred form of my threadingtool on the plane .I-I of'Fig. 2, with certain features in elevation; Fig. 2 is a transverse section on the plane II-II of Fig. 1, with certain features in eleva- 50 tion; i

Fig. 3 aplane development of a lead cam slot; v Fig. 4 is a plane development of a modified lead cam slot; l 65- Fig. 5 is an axial'sectionthroughn modified still another purpose is to assist the initial en-.

more adaptable than has'previo-usly been known Although shown and described as a hand-oper form of my invention, on the plane VV of Fig; 6, with certain features in elevation;

Fig. 6 is .a face view of Fig. 5, looking in the direction of the-"arrow VI; l C I Fig. 7 isa detail of a modified drive means, 6 applicable to the tool eitherof Fig. 1 or of Fig. 1 5, and on the same plane as the upper forward portion of either Fig. 1 or Fig. 5'; and

Fig. 8 is a detail illustrating an arrangement both to prevent dies from falling out of the die head, and to tend to expand them.

. Referring now to- Figs. 1 and 2, my improved die stock comprises a barrel 1 with a sleeve 2 on the rear and a diehead 3 on the front. Relative I movement is'allowed both axially and circumferentially between-"thesleeve and the barrel, and circtunferentially between the die head and the barrel. The sleeve carries the usual gripping and centering fingers 4 adapted to engage the work through cam slots 5 in the barreland operated 26 by a conventional scroll plate '6 and handle 1. i The movement of the cam slots 5 along the inwardly projecting ends of the fingers 4 gives a starting and leading motion directly to the bar rel, and with it-tdthe die'head, as described fig;

hereafter. An adjusting ring 9 is threaded "to' the forward end of the sleeve T2,'and can'be set in adjustment by the lock screw I0. orother suitable'means- This ring 9 adjusts the dies 8 ma manner explained later. The diehead 3 carries 3 the usual dies or chasers B. s

The-die head assembly is composed of various elements and attachments of a planetary gear system. The foundation ring or reactive gear .is a toothed ring l5 'showninFig. 1 as keyed by 3;, screws "if to the barrel I although of course it could be=inte gral.-- The planetary pinions ll, of which there are two in the present form, are carried on shafts I8 in a cage whereof thefrontmember'is the die head 3 and. the rear member f a ring is 'rotatablebn the barrel l and against the rear face of l5, front and rear-members being fastened together by bolts 20. A driving ring ticular-instance. The ring has the usual hanv dle sockets 21.

The dies 8 are'bottomed upon faces 32 out-* wardly and rearwardly inclined-along axially directed receding studs 34, the front ends of which project through suitable openings at the bases of the die sockets 30, and the rear ends of which are notched to the adjusting ring 9. The inclination of the faces 32 obviously determines the taper of the thread cut, and thus faces 32 with zero inclination (parallel to the axis) will cut straight threads.

The faces 32 terminate rearwardly in. sharply sloping shoulders 36 followed by notches 38. The length of the faces v32 determines the longest cut for which the tool is designed. There is a receding stud for each die, and at least some of these receding studs may project some distance in advance of the die head 3 to carry nuts 35 threaded on such projections, and short springs 35 between such nuts and the face of the die head. In the embodiment illustrated in Figs. 1 and 2, there are four receding studs, of which two opposite ones have springs while the other two, 34', do not project so far forward and do not carry springs. the dies on the work, as explained later.

A suitable arrangement for preventing the dies 8 from falling inward is shown inFig. 8. A spring-pressed detent 40, attached to the face plate 3 (or I03, Fig. 6) engages a nick M in the edge of the die strongly enough to hold the die against gravity, and the nick II is shaped or positioned to tend to press the dies radially outward against receding faces 32.

It is apparent from Fig. 1 that the studs 34 will be set forward or back with respect to the dies and die head by the position of the adjusting ring 9, to which they are engaged by a groove for axial movement. Such setting, which is made before work begins, obviously varies the initial radial position of the dies 8, thus causing a deeper thread to be started and carried through if the studs are back, or shallower if they are forward, but without altering either the starting position along the axis of the work, or the taper of the thread. Since the faces 32 are somewhat longer than the distance to be threaded, and the axial adjustment which the ring 9 can produce is relatively slight, such adjustment will not cause the dies to drop into the notches 38 too soon.

The cam slots feed the die head upon the work without relying upon the chaser teeth to do their own feeding. These slots 5 fit over the inner ends of the locking fingers 4. The fingers 4 do not move relatively to the pipe, andfor this reason the fingers 4 and sleeve 2 act as a fixedbase for all the movements .of the die stock and its parts, but the barrel I is subject to the reactive force on the gear I5, which tends to turn it in the opposite sense to the die head. Such tendency is directed by the cam slots 5 (or I05, Fig. 5 to assist in the} starting of the dies upon the work, but the action of the cam slots is not a positive determination of -movement, but only a tendency supplementing but subordinate to the force of advance of the die head as the dies cut their way onto the work. With my invention it is accordingly possible to cut-threads of different characteristics with the same die stock, of course using the proper dies, either Whitworth, U. S., Standard, or others.

The exact cam formation is obviously a matter to be related to the character of the thread being cut, the character of the dies selected to out the thread, and other factors, and the cams are so a designed to give more or less starting force and leading effect. One form of cam is shown developed in Fig. 3, wherein it will be seen that the rearmost or starting portion of the cam is a curve whose initial slope B is in this particular illustra- The springs 35' assist starting tion 60 to the axial line of the tool, flattening at C to a slope of and further flattening out to zero at D, at the front'end. It will be understood that these values are illustrative and not limiting. The purpose is to bring the die teeth quickly into engagement with the pipe, and feed at the proper rate for thread cutting as determined by the die teeth, but with the principal feeding stress on the cam instead of on the teeth.

The cam of Fig. 3 is recommendedfor cutting a taper thread. With such a thread the amount of metal removed by the die throat is greatest at the beginning of the cut, and progressively diminishes; therefore the amount of pull on is greatest at the beginning and diminishes as the threading progresses, and the curve of the cam is thus accordingly designed with the slope greatest at the beginning.

Where a straight thread is to be out, the amount of metal to be removed by the dies is constant throughout-the length and thus a straight cam such as 5', Fig. 4, is satisfactory. In Fig. 4, another fiat development, the portion of the barrel is indicated as I and except for the shape of the cam it is the same as the barrel I of Fig. 1, or the barrel IIlI of Fig. 5. A finger 4 fills the end of the cam slot, and the specific cam illustrated makes an angle of 15? with the axial line A-A of the barrel, as illustrated by the center line E.

A further pull on effect may be obtained by means of the springs 35, Fig. 1, already mentioned. These springs tend to move the die head 3 towards the fingers 4, sliding the barrel I through the sleeve 2. Thus when the fingers 4 are clamped on the pipe or rod, and the springs 35' compressed, with the throats of the dies 8. on the end of the work, the springs have a pull on effeet, which lasts until advance of the die head releases the compression.

A modified form of my improved threading tool is shown in Figs. 5 and 6. Elements on these figures which correspond to Fig. 1 are indicated, so far as appropriate, by reference characters IBI) higher than on Fig. 1. In Fig. 4 a work piece'W, in the present instance a' pipe, upon which threading is about to commence, is shown in the tool. The rear end of the tool is clamped as in Fig. l by fingers I04 passing through slots I05 in the barrel II. The planetary gearing arrangements are likewise the same, consisting of an outer ring I25 from which power applied by handles in sockets I2! is transmitted by an internally toothed gear I26 to planetary pinions I I1 which also mesh with the inner gear I I5, shown integral with the barrel IOI in this form.

The dies I08 in the die head I03 are bottomed on the receding faces I32 of studs I34, and the studs are notched as at I38 to allow the chascrs to move outward at the termination of their out. The adjustment of the posts I34 for full, medium or shallow cut is by their connection with a spider 50 movable toward or' from a stop bar 52 by a wing headed screw 53. The stop bar contacts'the front end of the work W, and a pin 55 prevents relative rotation between the bar 52 and the spider 58, so that the screw 53 will not betightened or loosened by rotation of the die head I03; The dies I08 may be held against falling inward by the same means as shown in Fig. 8. It is evident from the drawings that varying the space between the bar 52 and spider 50 alters the initial radial position of the dies I08 without changing their axial relation to the tool, so;that..full, medium or shallow threads may be out, just as by adjusting the ring 9 of Fig. 1. r

- In either forin of the" invntiom compound planetary gears IIA,v IIB, Fig. '1, maybe used in- 3 stead of the simple planetarygears, the driving and reactive gears 26A and I being appropriatelyaltered tol fit theisituation, all as shown in Fig.7, where the reference'characters correspond to those of Fig. 1, with suffix A, and the spur gear higher-order, in excess of 2:1. 1

hasa. large circumference HA and a small circumference IIB.:: I v v The operation of the form of invention shown in Fig. '1 will now be described, and that of the form shown in Fig.5 will bed'escribed in those particulars wherein it differs.

. The pipe, rod or boltis inserted in the barrel, and clamped in the usualmanner with the throat or enteringedges of the dies in. engagement with the end of the pipe- In the subsequent operations, the studs 4 and sleeve 2 actas a base toward l which the die head of the tool is drawn, chiefly by action of the cam slots- 5, 'andspring (if used) since one object of the invention is to relieve the die teeth from feeding work; The

handles 21 are now rotated in the cutting direction, and this motion is transmitted by the planetary reduction gear to the die head 3, thus moving the dies inthesame direction as the handles, but at a reduction preferably on theorder of 5:3, say 1.751. With the compound pinions of Fig. '7 thisinay be of a considerably As soon'as frictional contact is made between the dies and the workxthe' reaction turns the barrel 1 oppositely to the die head, causing the cam slot to travel on the 'studs l and so-first start the dies andthen feed them. Iffthe cam slot is that of Fig. 3, -ior ftaper threading (the usual situation) the bari'el moves at first witha substantial circumferential component, and a slight axial component, as indicated'by slope B, but the proportions of circumferential and ax-.

ial components gradually reverse, "for reasons heretofore explained.

' The dies are of cour's'e 'of proper size for what ever work is to be out, according tostanda rd- 4:;

matically open when they travel back to the notches 38, and in so opening the slopes 36 cause the roots of the threads to work out .with a smooth finish instead-ot-an abrupt bur. The notches 38 also serve as safety devices to disengage the dies fromthe work if a power-driven die stock is left running. After the dies are disengaged the die head "turns idly and thus no damage will result no matter how long the drive continues. V i

If only a short thread has been out, the tool is removed from the work without unwinding, asfollows; The operator releases the fingers 4 by the handle I and pulls the rear end of the tool (sleeve 2 and associated parts 5, I and so on) toward the die head 3. This slides sleeve 2 over the barrel l so that the notches 38 come under the dies 8, and the dies 8 are thus allowed to move radially outward, biased thereto by de-- tents Ml acting on the appropriate slopes of notches 41, and further assisted, if necessary, by the operator rocking the tool on the pipe. With end in opposite directions.

' on? "the cut threads.)

and the 'feed by the'cam slots-Hi5 will be shaped appropriately to the work,.as already discussed [In the form shown 'in' I 5, the threading tool is fastened on'the Work'I-W' as'in Fig. 71;] the gear drive is the same (or 'that of: Fig. 7),,

in describing Figs. 3 and 4. 'Theadjustment for;

' full or shallow threads: is by the spider 513 and stop bar 52, all heretofore described. When the tool. is clamped on the work by the, fingers it' l the adjusting elements can be pushed-back-b-y hand until the bar ,52 stops against theQfro'nt as in Fig.1, and the effect is as describe'd'for fall into the notches |38"an d"the tool canthen- .end. of .the work, and this places-the-dies IE8 inprope'rjradial position. To-cut threads with, thetool of Fig. '5', the handles are turned just that figure At the'endof theicut the dies I118 be pulled forward off the worl; by releasing the fingers lfl l. I I

When a shortthread is to be cut'either inanually or by power, but especially when operating by power, the operator 'can end the cut by pullfv ing the spider 5!! forward until ithe dies I68.

slide down the shoulders into the notches I38,- clearing the work. The shoulders act in the same manner as the shoulders 36 in guiding thei'die.

teeth gradually out of the work while'the threading action is still going on, and'so'finishing the threadswithout a bur. A

From theioregoing it will be'seen that I have invented a threadingtool inwhich an advantageous gear ratio is obtained in ahand'tool re ducing the pull which the operator has to ekert;

. Without increasingthe size: or'weight oft-he tool.

The direction in which the user turns the handies is'i -the same as -thedirection in which the cutting is accomplished, and in other respects the 1 operation of the improved. toolis familiar. 'The i use of alead screw is avoided without lossofit's' advantages. Unwindin'g the tool'to take it or?v the pipe and to reset the leadscrew is-eliminated. Oncesetfor any-'depth 'of cuti'the-settingjean al ways be brought back without adjustment. by pulling the front and rear'partsaway fro'rnone .The elimination of 1 a' lead screw offers numerous advantages It saves the-trouble and time of unwindingaftera out; itfpreventsjamming and breakage; it permits threads of different lead to be cut by the same threading tool with different dies.

As to, the saving of time, the provision of in combination with the cam slot, because by the use of the two features no unwinding, either notches on the receding studs is an advantage ing stud notch does not save time where a lead I screw is used because unwindingof the lead screw governs the time required, and takes as long whether or not the chasers ave to bebackedf,

Although cutting a thread "with the present tool (geared 3:5) takes 66% more turns of:th'e

handle than a gearless die stock requires to cut a thread of the same length, nevertheless; for'the total cycle of one cut 16 f ewer turns are.

needed than with a lead screw tool, because there is no backing ofi'orunwinding. Othermodes of applying the principle of my invention may be employed instead of the one explained, change being made as ,regardsthe respect to the forward end of said barrel and to the die head, and gear connections between said driving ring, said die head and said barrel.

2. In a threading tool, a barrel, a work-clamping assembly on the rear of said barrel axiallyv and circumferentially movable with relation thereto, a die head on the forward end of said barrel and rotatable With respect thereto, a driving ring rotatable with respect to the forward end of said barrel and to the die head, and gear connections between said driving ring, said die head and said barrel.

3. In a threading tool, a work gripping assembly comprising aring and work-clamping studs f therein, a barrel movable within said ring, cams on said barrel engaging said studs and adapted to guide movement of said barrel with respect to said studs, a die head rotatable with respect to said barrel, and gear connections between sai die head and said barrel.

4. In a threading tool, in combination, means for clamping a work piece, a die head rotatable with respect to said clamping means, die carrying means in said die head, studs extending longitudinally through said die head at points radially disposed from the center of said head, faces on the inner sides of said studs inclined outwardly from front to rear, bottom faces on said dies coacting with said inclined faces and adapted to rest thereon, a ring threaded to said clamping means and engaging'the rearward extensions of said studs but rotatable relatively to said extensions. p

5. A thread cutting tool comprising in combination a Work piece receiving member, a die carrying member rotatably mounted on said work piece receiving member, a driving member coaxially and rotatably mounted on said die carrying member, and a planetary reduction gear train drivably connecting said driving member to said mon axis, planetary reduction gear connections between said drivingring and said head adapted to rotate said head slower than said ring but in the same direction, a work piece receiving barrel differentially connected to said gear train, and cam means connecting said'barrel to the work piece for urging said barrel in the same axial direction as that of: said die head during thread cutting operation.

7. In a threading tool in combination, a'die head and a driving ring both rotatable on a common axis, planetary reduction gear connections between said driving ring and said head adapted to rotate said head slower than said ring but in the same direction, a work piece receiving barrel differentially connected to said gear train,

a work piece clamp with respect to which said barrel is slidable, and a cam of compound curvature on said barrel engagejable with a fixed bearing element carried. by said work piece clamp.

8. In a threading tool, a work piece receiving member, a die carrying member with radially movable dies rotatably, mounted on saidwork piece receiving member, a driving member coaxially and rotatably mounted on said die carrying member and a reduction gear train drivably connecting said driving member to said die carrying member and to said work piece receiving member, clamping means for attaching said work piece receiving member to the work piece, axially extending studs mounted in said die carrying member and having inclinedcfaces adapted to bear against and radially move said dies, and means for longitudinally adjustably connecting said studs to said clamping means.

- WILLIAM M. EMERY.

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