US2600349A

US2600349A - Die holder cap

Info

Publication number: US2600349A
Application number: US147611A
Authority: US
Inventors: Watson John
Original assignee: Greenfield Tap & Die Corp
Current assignee: Greenfield Tap & Die Corp; GREENFIELD TAP AND DIE Corp
Priority date: 1950-03-04
Filing date: 1950-03-04
Publication date: 1952-06-10
Anticipated expiration: 1969-06-10

Description

J. WATSON DIE HOLDER CAP June 10, 1952 Filed March 4, 1950 INVENTOR. John Woison.

ATTORNEY Patented June 10, 1952 Green field, Mass, a corporation of Massachusetts Applicatiorrllil arch 4, 19th,

1 Claim. 1

This invention relates to thread-cutting dies and more particularly to the die mounting for threading at high rotative speeds.

An object of the invention is to provide a die mounting which will be simple in form, inexpensive in manufacture and light and efiicient in operation.

A further object of the invention is to provide a special form of die holder cap for a die having a tapered slotted end.

Further objects of the invention, particularly in the formation of a three point support for a holder cap plate, will appear from the following specification taken in connection with the accompanying drawings in which Fig. 1 is a plan view of the die and holder;

Fig. 2 is a sectional view of the die and holder along line 2-2 of Fig. 1;

Fig. 3 is a perspective view of the cap; and

Fig. 4 is a sectional view of the cap along line 44 of Fig. 3.

Referring to the drawings, there is shown a threading device comprising a die holder H], a die II, a die holder cap [2, and a lock nut I3. The die holder Ill has a threaded portion [4 and a shank portion l5. Diametrically opposed lugs IB are provided on the holder H] to engage the grooves I! in the inner face l8 of the die II.

The die I I is provided with prongs or lands 2!], threads 2], and outer conical surfaces 22 terminated by the outer face 23. The inner face I8 seats against the end surface IQ of the holder l0. The cap l2 comprises a cap holder plate 25 and cap holder base 26. The base 26 is hexagonal in shape and has threads 21 adapted to engage the threads 28 to hold the cap I2 on the holder 10. The holder plate 25 is of a triangular shape with a circular opening centered in the middle. The opening has a cylindrical wall portion 32 and

conical walls

33 and 34. The conical wall portion 33 is at a lesser angle with the axis of the tool than the conical wall 34. The conical wall 33 engages the conical surfaces 22 holdin the die on the holder. The angle of taper of the conical walls 22 is less than the angle of the wall 34. Therefore the wall 33 contacts the surfaces 22 along the surface adjacent the edge 35 and the inner portions of the surfaces are slightly separated. The holder plate is rigidly secured to the holder base 26 by the equally-spaced posts 38 in each corner of the triangular shape forming a three element connection between the inner and outer members. The posts 38 comprise a spacer 39 and rivet 40. The spacer 39 is tubular in shape preferably cylindrical. The rivet 40 has a head 4| positioned in a seat 42 in the outer portion I2 and a shaft 43 extending through openings 44 in the rim of the portion [2, the tubular portion 39, through the opening 45 in the inner portion. The end of the rivet is peened over and forced into the seat 4! tightly holding the inner and outer members against the spacers 39. The surface 50 of the rim is below the surface of the opening with a bevel 5| between them. The posts 38 are widely spaced with large spaces between them for the discharge of the chips and cooling medium, keeping the cutting threads clean of the cuttings. The lock nut I3 is tightened against the inner portion of the cap to lock the cap in place and preventing it from loosening.

At high speed operation, the torque of the shank I5 is transmitted to the lug H at the die end and directly to the sides of the slot of the die itself so that the holder parts are carried around with the shank substantially torque-free.

The sole or main function of the cap parts is to accurately center the die jaws in adjusted position, the exerted force of the holder being an inward pressure on the outer tapered surfaces of the die. This pressure is converted substantially entirely to tension between the holder plate 25 and the holder base 26 and in the construction of this invention is transmitted through the three posts 38 which are assembled and headed over tightly to subject them to an initial tension snugly holding the holder plate 25 against the ends of the spacers 39 and so placing these spacers under initial compression. In this way the entire cap structure is made a unitary piece with no play or looseness between the parts which are relatively light and the complete assembly provides wide-open spaces discharging the chips outward from the die freely and. with no tendency to obstruct or pack the material within the holder parts.

A three point support is provided for the head plate and this automatically accurately supports the end plate by three points which necessarily fall Within a predetermined plane giving a precise and dependable positioning and permanent sustaining of the head plate tightly against the die surfaces in all positions of adjustment and use.

The supporting posts are symmetrically and equidistantly spaced around the center of rotation and. provide a light structure adapted for high speeds of rotation and offering very little obstruction to the discharge of material from the die under such speeds.

r 3 l I claim:

In combination with a, threading device having an externally threaded holder and a conical surfaced die keyed to the end thereof to turn therewith and comprising separated lands with spaces between them for the discharge of material from the die threads, a rigid cap structure consisting of a flat externally threaded annular base member on the threaded end of said holder, an outer plate member of generally triangular shape with a central opening surrounded by an inner conical wall diverging from the conical surface of the die and having its edge at said opening engaging the conical surfaces of the die along a line near the outer end thereof, sleeve spacers held between said base and plate members at the three corners of said plate member, and

4 rivets passing through said plate and sleeve members and normally under tension to hold said base plate and plate members against the ends of said sleeve spacers and in assembled position of the parts to draw said edge of said opening tightly onto the outer end of the conical die surface to center the die on the holder and press the die lands onto the work.

JOHN WATSON.

REFERENCES CITED UNITED STATES PATENTS Name Date Koehler Feb. 6, 1934 Number