US2257029A

US2257029A - Thread cutting tool

Info

Publication number: US2257029A
Application number: US401032A
Authority: US
Inventors: Zimmermann Charles
Original assignee: Individual
Current assignee: Individual
Priority date: 1941-07-03
Filing date: 1941-07-03
Publication date: 1941-09-23
Anticipated expiration: 1958-09-23

Description

Sept. 23, 1941. Q Z|MMERMANN 2,257,029

THREAD CUTTING TOCL Filed July 3, 1941 2 Sheets-Sheet 1' 3 ai JWW 7 harlea fimmrmnnn 3 THREAD CUTTING TOOL Filed July 3, 1941 2 Sheets-Sheet 2 7 56 if JJ J6 17 J5 M Z, M W 4! #9 59 51 vide means whereby Patented Sept. 23, 1941 UNITED STATES PATENT orrics 2,257,029 THREAD CUTTING TOOL Charles Zimmermann, Cincinnati, Ohio Application July 3, 1941, Serial No. 401,032

9 Claims.

This invention relates to a tool of simple construction adapted to be used for cutting threads in rods, pipes and the like, and more particularly to a tool provided with a plurality of cutting bits for engaging the member longitudinally spaced points relatively thereto.

More particularly, it is an object of the invention to provide a thread cutter of simple construction adapted to be readily attached to a conventional lathe and which is adapted to be supported thereby for engaging a member to be threaded which is rotatably mounted in the lathe.

A further aim of the invention is to provide a thread cutting tool having means whereby the cutting depth of the various varied relatively to one another thus providing means whereby each of the cutting bits will partially form the thread to thus reduce the amount of pressure on each of the bits to permit the cutting operation to be performed at a much greater speed than with conventional thread cutters having but a single cutting bit.

Still another object of the invention is to provide means for adjustably positioning the cutting bits relatively to one another so that the spaces between the cutting bits can be varied for forming a thread of any desired pitch.

Still a further aim of the invention is to prothe individual cutting bits can be readily released and moved to retracted positions so that while certain of the cutting bits are in projected, operative positions functioning for cutting the thread, other of the cutting bits can be in retracted positions and out of engagement with the member being threaded.

Other objects and advantages of the invention will hereinafter become more fully apparent from the following description. of the drawings, which illustrate a preferred embodiment of the thread cutting tool, and wherein-- Figure 1 is a top plan view of the tool,

Figure 2 is an end view in elevation of the same, showing the tool detachably clamped to a portion of a lathe,

Figure 3 is a cross sectional View taken substantially along the plane of the line 3-3 of Figure 1,

Figure 4 is a longitudinal vertical sectional view taken substantially along the plane of the line 4-4 of Figure 2,

Figure 5 is an enlarged horizontal sectional view of a portion of the tool, taken substantially along a plane indicated by the line 5-5 of Figure 3,

to be threaded and at cutting bits can be Figure 6 is a vertical sectional view taken substantially along the plane of the line 6-6 of Figure 5,

Figure '7 is a vertical sectional view taken substantially along the plane of the line I-'I of Figure 1,

Figure 8 is a horizontal sectional view of a portion of the tool taken substantially along a plane indicated by the line 8-8 of Figure 3, and

Figure 9 is a plan View, on a reduced scale, of a guide for setting the individual cutting bits, relatively to one another.

Referring more particularly to the drawings, wherein like reference characters designate like or corresponding parts throughout the different views, I0 designates generally a portion of a lathe carriage which is provided with an upwardly opening inverted T-shaped slot I I, as best seen in Figures 2 and 3. I2 designates a portion of the headstock spindle of the lathe, not shown, to which is connected in any suitable manner, a piece of work I3, which is illustrated as a rod and which is intended to be threaded by the thread cutting tool, designated generally Id. The parts I0 and I2 form parts of a conventional lathe and form no part of the present invention but are shown and described merely to better illustrate the application and use of the thread cutter I4 which is not a part of the lathe but which is adapted to be detachably connected thereto and to operate in conjunction therewith. The thread cutting tool I4 includes an elongated base I5 which is mounted on the carriage l0 longitudinally of its slot I I. The base I5 is provided with removable upstanding end walls It having upwardly and rearwardly enlarged rear portions H. A plate I8 is detachably supported at its ends on the upper edges of the forward portions of the end walls I6. Bolts I!) extend through registering openings 20 in the end walls I8 and the ends of the plate I8, and said bolts 59 extend into threaded openings 2| in the ends of the base IE to provide means whereby the lower, threaded ends of the bolts I9 are threadedly connected to the base I5 for detachably securing the end walls I6 to the base and the plate I8 to the upper edges of the end walls IS. A bolt 22 extends through the parts I5, I6 and I6, at each end of the tool I4. The bolts 22 are provided with lower threaded ends which extend into the slot II and which engage threaded openings 23 in the ends'of a bar 24 which is disposed in the enlarged, bottom portion of the slot II for clamping the thread cutting tool I4 to the carriage I0.

As seen in Figure 3, the plate I8 combines with the top of the base l5 to form an elongated horiprovided at its rear end with an T-shaped slot 45. A feedscrew Which, is secured at zontally disposed slot 25 which opens outwardly of the front side 26 of the tool l4 and which also opens outwardly of and terminates near the rear side 21 of the base l5. The plate I8 is provided with a longitudinally extending, elongated opening 28 near the front side 26 and which opens into the slot 25. A plurality of guides, designated generally 29 are slidably mounted in the opening 28, and inthe embodiment of the invention as disclosed, three guides 29 are provided. The guides 29, as best seen in Figures 3 and '7, each includes an enlarged lower portion 30 which is disposed in the slot 25 and which is provided with a downwardly opening slot 3| which extends therethrough, transversely of the tool M. The

guide 29, above its enlarged portion-3B, is provided with a restricted portion 3 2 which is dis posed in slidable engagement with the opening 28 and which combines with the portion 35 to form a surrounding shoulder 33 which engages the underside of the plate l8. its portion 32, is provided with a restricted up wardly extending externally threaded post 34 having a threaded longitudinally extending bore 35 for receiving a screw 36, the head of which is disposed above the upper end of the post 34. A washer 31 is 'mounted on the post 34 and rests against the upper-side of the plate I8, and a nut 38 engages the threaded portion of the post 34, above the washer 31. The nut'38 may be of any conventional type and is illustrated as being of a type adapted to'be turned by means of a spanner wrench, not shown. 7

An elongated cutting bit 39 extends through the slot 3| of the eachguide29. The number of cutting bits 39 corresponds to the number of guides 29, and said cutting bits 39 are disposed in the slot 25 and transversely of the tool i4, and are provided with sharpened cutting ends 48 which project outwardly from the front side 28 of the tool14.

Referring toF'igures3, and 6, the cutting bits 39 oppositely disposed outwardly opening recesses 4|. ,Each' of thebits 39 isconnected to a block 42. Each. block 42 is provided with a forwardly opening recess 43-forv receiving the recessed rear end of a bit 39. The blocks? is provided with set screws 44, disposed on opposite sides of the recess 43 and whichextend inwardly thereof for engaging the recesses 4! for detachablyconnecting the block 42 to thebit 39.. The block 32 is upwardlylopening 45'is connected to each of the blocks 42.. Each feed screw 46 is provided with an outer headed end 41 and an in ner end which is provided with a collar 48, a restricted stern portion 49 which projects outwardly from the collar 48, and a head 50 on the outer end of the stem 49. Stem? and head 56 turnably engage theT-shaped slot 45 for swivelly connecting the feed screw 46 to the block 42. Blocks 42: rest on top of the base I 5 and are disposed in or partly'in the slot 25, as seen in Figure Each of the feed screws 46 is provided with a collar or nut 5| which is turnably mounted on the threaded shank portion thereof, as best seen in Figure 4. The collars or nuts 51 are provided with diametrically opposed outwardly projecting The portions ll of the end walls I 6 are provided, adjacent their rear ends, with alined openings 53 for receiving the ends of a rod 54 which extends therebetween and its ends to the portions H by setscrews 55. Three levers 56 are pivotally Guide 29, above are provided, near their opposite ends, with are adapted to loosely engage in the mounted near their lower ends on the roo 54. The levers 56 are provided with openings 5! through which the rod 54 loosely extends so that the levers 56 are not only pivotally but slidably mounted on the rod 54. Levers 5B are provided with handle portions 58 at their upper ends, and at their lower ends, the levers 53 are bifurcated as seen at 59. As seen in Figures 2 and 3, the furcations 69 of each of the bifurcated portions 59 are each provided with a corresponding downwardly opening slot 6|. portions 59 is adapted to engage loosely over a nut or collar 5! and the pair of pins 52 thereof slots M of the furcations 60 thereof for pivotaily and slidably connecting each lever 5'0 to a feed screw 46.

' The portions l1, adjacent their forward ends, 7 areprovided with alined openings 62 for receivingthe round ends of a rod or shaft 53. The portion of the shaft 53 which is disposed between the endwall portions I1 is square in cross section, as seen inFigureS, and the rounded ends of the shaft 63 are prevented from rotating in the openings 62 by means of set screws 64, which provide means for securing the shaft'63 so that its sides are at any desired angles relatively to the horizontal and perpendicular and, as seen in Figure 3, one side of the shaft 63 faces upwardly and slightly rearwardly. A latch arm 65 is pivctally mounted on a screw 66, intermediate of Latch arms are its ends, on each lever 56. pivotally connected to the levers 55 between the rod 54 and their upper, handle ends 58. Each latch member 65 is provided with a handle portion fil at its upper end. The lower ends of the latch members 65 are each provided with a flat 63 to prevent the levers 56 from being swung forwardly of the threadcutting tool l4, at their upper ends.

6An anchor member ii! is mounted in each lever 9 1'2 tendto of the levers 55 forwardly andthejlatch members are provided to retain the levers 53 n the full ,line positions of Figures 2 and 3 against the action of the springs 12. 7 l, The lathe carriage I9 is adapted to be moved parallel to the longitudinal moving the cutting tool l4 in a similar direction. The work i3 is adapted to be revolved by the headstock stem l2 and the rotation thereof is synchronized with the movement of the carriage H), in a conventional Each of the bifurcated urge the upper ends 7 latch members 55, carried thereby, in the position, as indicated in full lines in Figure 2 so that the cutting bits 39 will be in projected positions. The cutting bits 39 can then be adjustedforwardly or rearwardly by turning their follower screws 49 to position them to cut to the desired depth, and the bits 39 are preferably positioned so that the leading bit 39 will partially form the thread, the intermediate bit 39 will further complete the cut, and the bit 39 at the opposite end of the tool I will complete the finished out to form the thread. By loosening the nuts 38 the guides 29 can be slid longitudinally of the tool I4 and the feed screws 46 connected to the bits 39 of the guides 29 and the levers 56, connected to the feed screws 49, will, together with the feed screws, be moved in conjunction with the guides 29 and the bits 39 to thus provide means for adjustably positioning the bits relatively to one another so that they can cooperate to cut threads of any desired leading cutting bit 39 has completed its cutting operation on the rod l3 and has been released by a downward pressure on the latch handle 61 which released the latch of the lever 53 associated with the bit, so that its spring 12 could retract the leading bit to prevent it from striking the spindle I2. As a result, this leading bit 39 is disposed in an inoperative position while the other two cutting bits are still functioning, and it will be readily apparent that this could readily be accomplished without interruption of the operation of the tool l4. In Figure 9 a setting gage, designated generally A, is shown which can be employed for correctly spacing the bits 39 for cutting a thread of a certain pitch by inserting the cutting ends 40 into the notches a thereof, which are shaped to fit the cutting ends 40. The gage A can thus be employed not justing the cutting depths of the different bits by varying the positions of the ends 49 relatively to the notches a. It will be obvious that a plurality of guides or setting members A could be provided having differently spaced notches a. for setting the bits 39 for cutting threads of different pitches.

It will be apparent that to release the tool M to enable it to be returned to a position for making another cut, it is only necessary to press downwardly on the latch handles 61 to release the latches 65 so that the springs 12 can act on the levers 56 for retracting the cutting bits 39, inwardly of the slot 25. Consequently, if another piece of work l3, of the same diameter, is to be chased with a thread of the same depth and pitch, it will only be necessary to return the levers 59 to the full line position of Figure 2 to again project the bits 39 to their correct cutting positions, after the carriage l9 and tool i l have been returned to a position to begin another thread cutting operation.

The thread cutting tool can be made for any size engine lathe and the tool can be provided with either three or four cutting bits.

Various modifications and changes are contemplated and may obviously be resorted to, provided they fall within the spirit and scope of the invention as hereinafter defined by the appended claims, as only a preferred embodiment of the invention has been disclosed.

I claim as my invention:

1. A thread cutting tool comprising a base adapted to be detachably clamped to a portion of a lathe, said base being provided with upright pitch. As seen in Figure 1, the

only for spacing thebits 39 relatively to one another but also for adprovided with guides slidably mounted in said slot, a plurality of end walls, a plate'detachably fastened to said end walls and disposed aboVeJand spaced from the forward portion of said base, said plate being a longitudinal slot, a plurality of cutting bits-slidably engaging said guides: and disposed to move transversely ofv the base, feed screws swivelly connected to the rear ends of; said bits and projecting rearwardly from the thread cutting tool, a collar threadedly engaging each of said feed screws, each of said collars being provided with diametrically opposed outwardly projecting studs, a plurality of levers slidably and pivotally mounted on the thread cutting tool, said levers having yoke shaped lower ends for engaging over said collars, said yoke shaped ends being slotted to engage said studs, spring means for urging the upper ends of said levers forwardly of the tool for retracting the feed screws and cutting bits, and latch means carried by said levers for holding the cutting bits and feed screws in projected positions.

2. A thread cutting tool as in claim 1, said guides being movable relatively to the plate for moving the cutting bits, feed screws and levers longitudinally of the base for adjustably spacing the cutting bits relatively to one another.

3. A thread cutting tool as in claim 1, said guides being movable relatively to the plate for moving the cutting bits, feed screws and levers longitudinally of the base for adjustably spacing the cutting bits relatively to one another, and

said guides being provided with clamping means for engaging the plate for retaining the cutting bits in adjusted positions relatively to one another.

4. A thread cutting tool as in claim 1, comprising a rod detachably mounted in the rear ends of said end walls and on which said levers are pivotally and slidably mounted, a second rod detachably mounted at its ends in said end walls and forwardly of said first mentioned rod, said second rod being square in cross section, and said latch means including pivotally mounted lever arms carried by said levers and having lower end portions for detachably engaging said second rod for preventing the upper ends of said levers from being swung forwardly by the action of said spring means to retain the cutting bits in projected positions.

5. A thread cutting tool comprising a plurality of cutting bits, the longitudinal axis of said tool being disposed parallel to the longitudinal axis of the member to be threaded thereby, said cutting bits being spaced from one another longitudinally of the tool and being disposed transversely thereof, guide means for slidably mounting said bits, said guide means being movable longitudinally of the tool for adjustably spacing the bits from one another, pivotally mounted levers connected to said bits for advancing and retracting the bits, and latch means associated with said levers for holding the bits in projected positions.

6. A thread cutting tool as in claim 5, comprising spring means for normally urging the bits to retracted positions.

'7. A thread cutting tool as in claim 5, com prising means for adjustably connecting said levers to the bits for varying the cutting depth of the bits, when in their projected positions.

8. A thread cutting tool comprising a tool frame provided with a plurality of cutting bits, said cutting bits being spaced from one another in a direction parallel to the longitudinal axis of a member to be threaded thereby, means for adpar-allelic one .anothen'rleversconnected-tosaid V 9. 1A thread cutting tool as in claim 8; .com;

prising"meansforadjustfibly connecting said out- .ting-bits and leve rs for adjusting ,the cutting depth. of the bits, when in projected positions,

cuttingmits for projecting-rand retracting-"the 5 independently'of one another.

cutting bits, vand; latch. :means 1 c'arrie'd by said levers vfnr holding-.1 the 5- cutting bits: in projected positions't.

CHARLES ZIMME'RMANN.