US2486044A

US2486044A - Tap grinding fixture

Info

Publication number: US2486044A
Application number: US770121A
Authority: US
Inventors: William J Lusk
Original assignee: Individual
Current assignee: Individual
Priority date: 1947-08-22
Filing date: 1947-08-22
Publication date: 1949-10-25
Anticipated expiration: 1966-10-25

Description

Oct. 25, 1949. w. J. LUSK TAP GRINDING FIXTURE Filed Aug. 22, 1947 Patented Oct. 25, 1949 UN?! TED .S TATES PATENT s-FICE TAP -GRINDING FIXTURE WilliamaLLusk, Ber-ea, Ohio Application August'22, 1947, Serial No. 740,121

2-Claims. 1

This invention relates to grinding m'a'chines and to fixtures adapted .fbl supporting taps and similar devices during the grinding pperat'i-on.

An object of the invention is to vprovide:aftap grinding fixture which is 'adaptetl to support :a tap in position to be operated upon by :a .gsrinding wheel and the like.

Another object of the invention-is to provide a tap "grinding fixture adapted to reclaim ldmll or broken tape by cutting offfithe end and regrinding with the proper lead and taper.

A further object of the invention is to provide a tap grinding fixture incorporating easily acljustable means for :regrin'ding taps with two or four flutes es the-case may be.

Still another object of the invention is to rovide-atop grindinglilxture which is simple'in de sign, inexpensive to manufacture, and which is effective in operation and quickly and easilyadiustable for the *grinding operat-ion, andrthen easily releasable for removing the tap thereafter.

Otherobiects and advantages of the invention will become apparent from' the following description of a preferred embodiment thereof-as illustrated in the accompanying drawing, and in which:

Figure l isa right end elevationof the device shown inFigure 1.

Figure 2 is a longitudinal sectional elevation of my improved tap grinding fixture, taken on line 2-2 of Figure '1.

Figure 3 is an elevationaldetail view of the tap gripping collet employed in the device, shown separately.

In the regrinding of broken or worn taps, it is :2

spiral flutes therein, two or four flutes being ground in as the case may be. The present application discloses means for accomplishing this easily and efficiently.

In order to understand clearly the nature of the invention and the best means for carrying it out, reference may now be had to the drawings, in which like numerals denote similar parts throughout the several views.

As shown, there is a fixture body indicated generally at [0 and including a hollow cylindrical housing l2 supported upon a base [4 by upright leg-like members I6, all formed or cast as an integral unit. An opening I8 is thus formed in the space between the leg members l6, affording access to the middle portion of the fiat top sur- .2 face 26, thus permitting 'a single bolt to be inserted through the vertical bore 2 2 in the basetfor single bolt mounting thereof.

The base of the .fix'ture thus clamps securely to the grinding table inpositionfor cooperation with the grinding wheel usually :also carried thereby. A longitudinal bore :24 :is .formed 'in the "cylindrical housing l2 to receive the outer cylindrical sleeve 26, the sleeve beingithus turna-ble about its axis within the housing bore. The outer sleeve 26 is provided'at one end with an annular lintegral collar 1or.1'-lange.'28 one radial wall of which abuts against the 'outer end of the cylindrical housing 1-2.

annular retaining collar :36 encircles the opposite end of the outer sleeve :26, thus serving to retain the outer sleeve in position against displacement from the bore 24. .An --eccentriclongttudinal bore 34 is .formed inth'eoute-r sleeve 26.. its "eccentricity being best shown in Figure :1, to receive an inner sleeve 32 which is similarly provided with an outer flange-=36 abutting against the end surface of the outer sleeve 26.

As-seen'loestin Figure 2, the inner :sleeve32 extends wholly through the outer sleeve .26, their left :hand eends being co extensive .and -.secured together by means of a set screw :38 extending through a radial :bore 40 formed through the overlying outer sleeve and collar 36 the inner end of the screw extending into the annular groove 39.

The rotary travel of the :outerisleeve 26 i's'c'ontrolled by a radial -handle*4"ll the shank'of which extends through an rarcuate motion limiting 'slot 42 formed in the housing 42, the :inner end :of the handle shank being threaded :into a radi'al .bore 44 fformed in the sleeve -26. v.'Ihe'=o1'1ter:sleeve also has a positioning pin assembly indicated generally at 44. The assembly 44 is disposed in a radial bore 46 formed in the flange 28 of the outer sleeve, and includes a plunger shaft 48 the outer end of which has an integral knob 50 and the inner portion of which extends through the radial bore 46, being almost as large in diameter as the I; bore 46 at its inner end.

The reduced shank of the shaft 48 extends slidably through the axial bore in a nut or plug 52 which is threaded into the enlarged outer end of the radial bore 46. A spring 54 encircles the inner portion of the shank of the shaft 48 between the enlarged plunger portion thereof and the nut 52, thus biasing the plunger portion of the shaft 48 radially inwards toward the outer surface of the inner sleeve 32. Under this biasing influence, the positioning plunger 48 is thus 3 pressed into any Selected one of four radial recesses 56 which are formed in the outer surface of the inner sleeve 32, and are spaced from each other by ninety degrees.

The positioning knob 50 is pulled radially outward and the parts turned to bring the bore 46 into registry with any selected positioning recess 56, the knob 50 then being released to allow the spring to press the plunger into the underlying recess 56. The set screw 38 is then tightened so its inner end presses firmly into the annular turned groove 39, holding the parts securely in position.

The inner sleeve 32 has an axial bore 60 extending longitudinally therethrough to receive a collet tightening shaft or draw bar 62 to the outer left hand end of which is secured a turning knob 64 whereby the shaft may be turned. The right hand end of the axial bore 60 is enlarged to receive the shank of a collet 66 having jaws 68 adapted to receive therebetween the shank of a tap to be ground. It will be seen that the right hand end of the shaft 62 is threaded into the left hand end of the collet shank so that upon turning the knob 64 the collet is drawn in a leftward direction to press its gripping jaws toward each other under the camming influence of the cam surfaces 68 of the collet. The tap is thus held securely in the collet in this manner.

To use the fixture, the tap to be ground is inserted in the collet 66 and tightened by means of the draw bar 62. Thereafter the position pin 48 is used to position the tap for either two or four fiutes as the case may be, and the handle 40 is turned within the limits of the-slot 42 each time the tap is positioned by pin 48, the grinding wheel thus operating upon selected flutes on the tap.

Although I have described a preferred embodiment of my invention in specific terms, it is to be understood that various changes may be made in size, shape, materials and arrangement without departing from the spirit and scope of the invention as claimed.

I claim:

1. A workholder for supporting a workpiece for limited eccentric rocking movement about a longitudinal axis, said workholder comprising a base, said base having a longitudinal tubular housing having a concentric bore, an outer tubular cylinder rotatably fitting said concentric bore, said outer cylinder having a bore parallel to but eccentric with respect to said concentric bore, an inner cylinder rotatably fitting said eccentric bore, means preventing sidewise movement of said outer and inner cylinders and said housing relative to each other, a workpiece clamping collet arranged to project axially from one end of said inner cylinder, indexing means operating between 4 said outer and inner cylinders for releasably holding said inner cylinder in any one of a number of different predetermined positions of rotation of said inner cylinder relative to said outer cylinder, and handle means on said outer cylinder arranged for rotating said outer cylinder relative to said cylindrical housing, said positions of rotation of said inner cylinder relative to said outer cylinder being equally circumferentially spaced from each otherfand means on said cylindrical housing limiting the swing of said handle means in either direction to a circumferential distance equal to the distance between adjacent ones of said positions of rotation.

2. A workholder for supporting a workpiece for limited eccentric rocking movement about a longitudinal axis, said workholder comprising a base, said base having a longitudinal tubular housing having a concentric bore, an outer tubular cylinder rotatably fitting said concentric bore, said outer cylinder having a bore parallel to but eccentric with respect to said concentric bore, an inner cylinder rotatably fitting said eccentric bore, means preventing sidewise movement of said outer and inner cylinders and said housing relative to each other, a workpiece clamping collet arranged to project axially from one end of said inner cylinder, indexing means operating be tween said outer and inner cylinders for releasably holding said inner cylinder in any one of a number of different predetermined positions of rotation of said inner cylinder relative to said outer cylinder, and handle means onsaid outer cylinder arranged for rotating said outer cylinder relative to said cylindrical housing, said positions of rotation being equally circumferentially spaced, said handle comprising a radial arm fixed to project from said outer cylinder, said cylindrical housing being formed with-a circun-iferentially extending slot passing said arm and of a length to limit the swing of said handle arm in either direction to a distance equal to the distance between any two adjacent positions of rotation of said inner cylinder.

WILLIAM J. LUSK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Dawson Dec. 31, 1946