US3681802A

US3681802A - Die head

Info

Publication number: US3681802A
Application number: US70988A
Authority: US
Inventors: Donald E Youtz; Edwin M Eigenbrode
Original assignee: Teledyne Inc
Current assignee: Teledyne Inc
Priority date: 1970-09-10
Filing date: 1970-09-10
Publication date: 1972-08-08
Anticipated expiration: 1989-08-08

Abstract

A die head for roll forming threads or other formations on a workpiece in which a plurality of dies are rotatably supported in die holders bodily received in recesses in the head for rotation therein to move the dies toward and away from the axis of the head.

Description

United States Patent Youtz et al. [451 Aug. 8, 1972 [54] DIE HEAD 2,252,130 8/1941 Lamprecht et a1. ..72/126 72 Inventors: Donald E. Y Ed M. E- 2,349,863 5/1'944 Hallberg ..72/126 1 bmde, both xg i 2,909,087 10/1959 Powell ..72/103 l 3,196,650 7/1965 Kruse ..72/126 [73] Ass1gnee: Teledyne, Inc., Los Angeles, Calif. 3,352,139 11/1967 Cummings ..72/l04 [22] Filed: Sept. 10, 1970 [21] Appl. No.2 70,988 Primary Examiner-Charles W. Lanham Assistant Examiner-E. M. Combs 52 U.S. c1. ..10/96, 72/104, 72/123, A'w'nekstmuch Neale Nies Km 408/148, 408/153, 408/173 r [51] Int. Cl ..B23g 1/00 B23g 5/10, B23g 5/12 58 Field of Search ..10/111, 152, 94, 96; 72/102, [57] ABSTRACT 72/103, 104, 105, 107, 123, 126; 408/ 146, A die head for roll forming threads or other forma- 147, 148, 153, 173 tions on a workpiece in which a plurality of dies are rotatably supported in die holders bodily received in [56] References Cited recesses in the head for rotation therein to move the dies toward and away from the axis of the head. UNITED STATES PATENTS 631,159 8/1899 Echols ..72/104 3 Claims, 4 Drawing Figures PATENTEBm 8 am 31681; 802

SHEET 10E 2 20 INVENTORS 2 mizrg rla reoos wzaww ATTOR YS PATENTEDAUBHBIBYZ 3.681.802

SHEET 20F 2 INVENTORS DONALD E.YOUTZ EDWIN M. EIGENBRODE ATTORN DIE HEAD BACKGROUND or THE INVENTION Die heads of the general type with which the present invention is concerned have long been in widespread use for the formation of threads, splines, knurls, or like formations on cylindrical workpieces.

Such die heads carry a number of dies, usually three, which roll in pressure contact with the workpiece as the workpiece and head are relatively rotated and relative ly moved along the axis of the workpiece. At the conclusion of the rolling operation the dies are withdrawn radially from the workpiece which is then withdrawn axially from the head. The dies are then returned to their rolling position and the rolling operation is repeated on successive workpieces.

The mechanism for supporting the dies in the die head is of critical importance to the successful performance of the head. The dies must be readily moveable into and out of the rolling position and yet must be rigidly supported in rolling position despite the imposition of relatively high loads on the dies. In the past, these objectives have been achieved to a certain extent but only by the provision of mechanism which is costly to manufacture and to replace after wear.

SUMMARY OF THE INVENTION With the foregoing considerations in mind it is the principal purpose and object of the present invention to provide improved means for supporting dies in a die head for rolling threads or like formations on cylindri' cal workpieces which materially reduces the original cost of the die head, and permits continued operation of the die head with substantially reduced maintenance costs.

It is a further object of the present invention to provide improved means for supporting dies in a die head with extreme rigidity to assure accuracy of the forming operation and yet which is readily adjustable for initial sizing, and which may be readily moveable between die-closed and die-open positions.

In attaining these and other objects, the present invention provides a unique die head having a central space for the reception of the workpiece and a plurality of cylindrical recesses arranged around and opening into the space. The recesses are closed at one end by a face plate detachably secured to the die head. A die holder is bodily received in each recess, the die holder having a peripheral cylindrical surface and having parallel end faces received with a close clearance fit between one end face of the die head recess and the inner surface of the face plate. Thus, essentially the entire external surface of the die holder is utilized to journal the holder for rotation about its axis and to retain the holder against endwise movement.

Each holder carries a rolling die which is mounted for rotation in the holder about an axis spaced from the axis of the holder. Accordingly, when the holders are angularly displaced about the head axis the dies will be moved toward and away from the axis of the work receiving space, either for initial sizing adjustment or to effect the opening and closing movements of the die head.

Since both the die head recesses and the die holders are of essentially cylindrical configuration, they may be machined to the necessary close tolerances at minimum expense. Also because of the unusual large bearing area provided, wear on the die head and die holders is reduced to a minimum assuring an extended service life.

In the caseof extremely small diameters'of work it becomes increasingly difficult to incorporate sizes which are within a desired range of a die head of this type. This is especially true when a means of self opening roll dies of a relatively small diameter must be taken into consideration. The diameter of these dies must be decreased as the size of work becomes smaller in order to prevent their clashing together in closed position. Because of the unique construction of the roll holders of the subject invention the problem is solved as the small roll dies can be readily adapted to the roll holders.

Conventional means for opening and closing the die head as well as for achieving initial set up adjustment may be readily adapted to operate the die holders of the present invention.

Additional objects and advantages of the invention will become apparent as the description proceeds.

THE DRAWINGS FIG. 1 is a central section through the die head of the present invention;

FIG. 2 is a side elevation of the die head partially broken away;

FIG. 3 is a rear elevation of the die head; and

FIG. 4 is a fragmentary section taken along line 4-4 of FIG. '1.

DESCRIPTION OF PREFERRED EMBODIMENT Referring now more particularly to the drawings, the thread rolling head comprises a hollow body member 20 having a hollow shank 22 adapted to be mounted in or on a machine spindle in accordance with conventional practice.

The head body has an intermediate section for rotatably supporting an adjusting ring 24 and a closing ring 26 and an enlarged forward portion 27 mounting the dies 28 and the associated holder assemblies 30 as will be described.

The adjusting ring 24 is mounted for limited rotation on the head body and is held in adjusted rotated position by a pair of opposed adjusting screws 32 (one shown) the inner ends of which engage a pin 34 carried by the head body 20. The adjusting ring is held snugly against a shoulder 36 on the head body by a snap ring 38.

A trip pin 40, forwardly biased by a spring 42, extends through the adjusting ring and at its rearward end is provided with a pair of

pins

44 and 46 adapted to engage the opposite faces of a trip plate 48 mounted for rocking movement between the full line and dotted line positions of FIG. 2 on a pivot pin 50 carried by the adjusting ring.

The closing ring 26 is mounted for limited rotation on the head body between the rear face 52 of the head bodyenlargement 27 and the front face of the adjusting ring 24. The closing ring is normally held against rotation by a pair of latch pins 54 which are axially slidable in the adjusting ring and are moved axially by a trip plate 48 which is provided with key hole slots 56, the side edges of which engage suitably formed side slots in .the pins 54.

Normally the pins 54 occupy the full line position of FIG. 2 with their inner ends received in openings 57in the closing ring to lock the closing ring against rotation. When the pins are withdrawn from the closing ring by movement of the trip plate to the dotted line position of FIG. 2, the closing ring is angularly displaced by opening springs 58 (one shown) compressed between the ends of a recess 60 in the adjusting ring, and rearwardly projecting pins 62 (one shown) in the closing ring.

The structure thus far described is per se essentially conventional.

The present invention is concerned with means for mounting the dies 28 and the association of the die mounting means with the previously described mechanism.

The dies 28 are of generally cylindrical form and are provided with suitable peripheral formations complementary to the surface formations to be produced on the workpiece. The apparatus of the present invention preferably includes three such dies which are mounted in equally spaced relation around the axis of the head. In apparatus of this type it is essential that the dies be located. and oriented with precision; that they be equally adjustable by a simple mechanism; that they be readily and simultaneously moveable between closed and open positions; that they be supported with extreme rigidity to assure accuracy of the work despite the development of rather high operating forces, and that the parts be subject to minimum wear and be relatively inexpensive to manufacture. The mechanism for supporting the dies, which will now be described in detail, satisfies all these objectives.

Each die 28 is mounted for free rotation on a cylindrical shaft 64, the opposite ends of which are received in aligned bores 66 and 68 in the die holder 30. The shaft 64 is held against rotation by a lock screw 70, the inner end of which bears against a flat 72 on the adjacent end of the shaft 64. The end faces of the die 28 are received with a close clearance fit with the end faces of a semi-cylindrical slot 74 in the die holder, which provides a large bearing surface to assure continued proper axial positioning of the dies 28.

The major portion of the outer surface of the die holder 30 is formed as a cylinder, the cylindrical surface being received in the corresponding segment of the cylindrical surface 76 of the recess formed in the enlarged portion 27 of the head 20. The die holders 30 are axially positioned with a close clearance fit against the inner radial face 80 of the recess by a face plate 82 secured as by a plurality of screws 84 to the head 20.

A control pin 86, an integral part of the holder 30, extends through a circumferentially elongated slot 88 in the head body into a radially elongated slot 90 in the closing ring 26. Accordingly, upon rotation of the closing ring, the pins 86 are displaced circumferentially thus rotating each of the holders 30 about its axis. Since the die shaft 64 is displaced radially from the axis of the holder 30 the dies are correspondingly displaced radially of the die head between open and closed positions. Initial adjustment of the position of the holder 30 for set up and sizing is effected by adjustment of the adjusting screws 32 which rotate the adjusting ring 24 with respect to the head body carrying with it the closing ring 26 and the pins 86.

In operation, assuming the die head is closed, i.e., in the position of FIG. 1, the workpiece is placed in a rotating chuck and the die head is axially advanced onto the workpiece and the appropriate formation is produced on the end of the workpiece. When a workpiece has been formed to the desired length, a stop member not shown, in fixed relation with the workpiece contacts the end of the trip pin 40. The trip plate is pivoted to the dotted line position of FIG. 2 withdrawing the pins 54 from the closing ring 26, which is then rotated by the opening springs 58 to move the dies 28 out of contact with the workpiece which is then withdrawn. The closing ring is then restored to its closed position by manual or mechanical operation of a projection 92 formed integrally with the closing ring. As soon as the openings in the closing ring are aligned with the pins 54 the spring 42 restores the trip plate 48 to its original position locking the closing ring in its original position.

It will be noted that the cylindrical body of the holder 30 is interrupted by a flat surface 94 providing the clearance necessary to permit the apparatus to move between the closed and open positions and to permit the surface of the dies 28 to project into contact with the workpiece. At the opposite edges of the flat surface 94 the surface of the holder 30 is notched to provide

radial surfaces

96 and 98 which function as scrapers acting against the cylindrical surface 76 of the head body recess to eliminate chips from adjacent cutting operations or dirt which might otherwise be wedged between the outer surface of the holder 30 and the mating recess surface.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

The embodiment of the invention in which an exclusive property or privilege is claimed is defined as follows:

l. A die head comprising a body member having an annular die mounting portion and a central opening for the reception of a workpiece, said body portion having a plurality of recesses equally circumferentially spaced about the axis thereof, said recesses having cylindrical surface portions the axes of which are parallel with the axis of said body member and said recesses intersecting and opening into said central opening, a die holder in each of said recesses, said die holders having cylindrical peripheral surfaces in engagement with the cylindrical recess surfaces to be rotatably supported thereby and each die holder having a recess intermediate its ends, each recess opening laterally of said holder into said central opening, means on each die holder for supporting a die in said die holder recess for rotation about an axis spaced from the axis of said holder, and means for simultaneously rotating each of said holders about their axes to move said dies toward and away from said axis of said head.

2. A die head according to claim 1 wherein said body member has a radial end face essentially perpendicular to the axis of said body member and wherein said recesses in said body member extend to said radial 3. The die head according to claim 2 wherein the recesses in said die holders have side faces essentially perpendicular to the axis of said body member for engagement with the opposite end faces of a die received in said recess.

Claims

1. A die head comprising a body member having an annular die mounting portion and a central opening for the reception of a workpiece, said body portion having a plurality of recesses equally circumferentially spaced about the axis thereof, said recesses having cylindrical surface portions the axes of which are parallel with the axis of said body member and said recesses intersecting and opening into said central opening, a die holder in each of said recesses, said die holders having cylindrical peripheral surfaces in engagement with the cylindrical recess surfaces to be rotatably supported thereby and each die holder having a recess intermediate its ends, each recess opening laterally of said holder into said central opening, means on each die holder for supporting a die in said die holder recess for rotation about an axis spaced from the axis of said holder, and means for simultaneously rotating each of said holders about their axes to move said dies toward and away from said axis of said head.

2. A die head according to claim 1 wherein said body member has a radial end face essentially perpendicular to the axis of said body member and wherein said recesses in said body member extend to said radial face, the recesses having an inner end face essentially perpendicular to the axis to said body member and said die holders having one end face in engagement with said inner end face of said recess, and a face plate detachably secured to said radial end surface of said head and having surface portions in engagement with the opposite end face of each of said holders.

3. The die head according to claim 2 wherein the recesses in said die holders have side faces essentially perpendicular to the axis of said body member for engagement with the opposite end faces of a die received in said recess.