US3196650A

US3196650A - Self-opening thread rolling head

Info

Publication number: US3196650A
Application number: US117179A
Authority: US
Inventors: Kruse Werner
Original assignee: Wilhelm Fette GmbH
Current assignee: Fette GmbH
Filing date: 1961-06-14
Publication date: 1965-07-27
Anticipated expiration: 1982-07-27

Description

July 27, 1965 W. KRUSE SELF-OPENING THREAD ROLLING HEAD Filed June 14 1961 L j I In ocular,-

By Au,

V I Attorneys,

United States Patent 1 3,196,650 SELF-OPENING THREAD ROLLING HEAD Werner Kruse, Schwarzenbek, near Hamburg, Germany, assiguor to Wilhelm Fette Prazisionswerkzeug-Fabrik, Hamburg, Germany Filed June 14, 1961, Ser. No. 117,179 Claims priority, application Germany, July 9, 1960,

31,265; Dec. 1, 1960, F 32,667

1 Claim. (Cl. 72-67) The invention relates to a self-opening thread rolling head and comprises a body member comprising threadformin-g rolls freely mounted on eccentric pin elements arranged concentrically around the workpiece and movable with a rocking motion into and out of the working position, and a shank including a workpiece stop, these parts being axially displaceable but prevented from relative rotation by a locking device arranged between the body member and the shank, this device being released when the workpiece strikes the stop.

In the known rolling heads of this kind it has been found disadvantageous that a considerable mass must be moved both when releasing and also when closing the locking device so that a strong spring is required and hence, after engagement of the workpiece and rotation of the displaceable part of the housing, there is an undesirably hard impact of this massive part of the housing against a stop limiting the displacement. Also the reengagement of the rolling head, which is effected by rotating the massive part of the housing by hand against the spring force, involves a considerable expenditure of energy.

According to the invention it is therefore proposed that one of the two main parts of the head be further divided and that only a portion of the said one part, of comparatively small mass, has to be rotated for opening and closing the thread rolling head.

A self-opening thread rolling head according to the invention comprises two main sections one of which includes freely rotatable threading rolls on eccentric spindles arranged concentrically around the workpiece by which the threading rolls may be moved into and out of the working position and the other consists of a shank portion comprising a hollow shaft and a workpiece stop, in which the section including the threading rolls is axially slidable relative to the other section and includes two relatively movable parts which, by their relative movement, move the threading rolls towards and away from the working position and are adapted to be held by locking means in that position in which the rolls are in the workpiece engaging position.

FIG.1 shows a related form of die rolling head while FIG. 2 shows a construction example of my invention.

In the embodiment shown in FIG. 1 the rolling head comprises two main sections, namely a shank section 3 and a body section 4 mounted upon the forward end of the shank section 3. The latter is adapted to be secured to a machine tool in a workpiece-engaging position and either the head or the workpiece is rotated to perform thread rolling. The shank section 3 is hollow and houses a workstop 5 adapted to be engaged by the end of a workpiece being threaded, for the purpose of effecting disengagement of the thread rolls as explained hereinafter.

The workstop 5 is screw threaded for a sleeve.6 at the rear end which is in threaded engagement with a screw threaded bore in the rear end of the shank part 3 and is adapted to be fastened after adjustment by means of a lock nut 7. This adjustment permits the length of thread produced on the workpiece to be adjusted.

The body section 4 comprises two relatively rotatable members including a forward member 8 having a splined 3,196,650 Patented July 27, 1965 "ice bore adapted to engage splines formed on the forward part of the shank 3 so that the member 8 can slide axially upon but cannot rotate relatively to the shank 3. The second member of the body section 4 comprises two

cylindrical parts

9 and 10 which are adjustably coupled 'one to the other by means of a spaced series of fastening studs 11. There may be three such studs spaced uniformly around the head and said studs are fixedly screwed into threaded apertures in the part 9 and traverse arcuate slots in the part 10 so that a limited adjustment between these parts is possible. The

parts

9 and 10 may be fixed in the adjusted positions by means of nuts 12 on the studs 11 which clamp the part 10 against the part 9. The part 9 may be provided with a circular boss-like portion accommodated within a recess in the rear face of the member 8 and these parts may be held in engagement by means of a ring 15 fixed against an end face of a hub portion of the member 8 by means of fastening screws 16, the outer edge of the ring 15 seating against a stop face of the part 9.

Projecting outwardly from the part 9 is an operating lever 17 by which the

parts

9 and 10 may be rotated as a unit relatively to the member 8 for the purpose of closing the thread rolls into the working position ready for engagement with a workpiece to be threaded.

Located in front of the member 8 is a front plate 18 supported from the member 8 by means of spacer blocks 19 which are in threaded engagement with the member 8, the front plate 18 being fastened to the spacer blocks 19 by means of countersunk fastening screws 20. The front plate 18 is centrally apertured at 21 to admit a workpiece to be threaded.

Thread forming rolls 22 are rotatably accommodated upon eccentric spindles 23 by means of needle roller bearings 24. The eccentric members 23 form part of carrier spindles 25 accommodated in apertures in the front plate 18 and in the member 8.

The thread forming roll-s 22 are provided with a series of parallel peripheral thread forming grooves and the support spindles 25 are placed slightly obliquely to the centre axis of the head at an angle corresponding to the mean helix angle of the thread to be rolled.

The rearmost end of each spindle 25 extends into a recess 26 formed in the body member 8 and carries a projecting arm 27 to which a crank pin 28 is fixed. This crank pin engages a slot 29 in the part 9 so that rotation of the

parts

9 and 10 relative to the member 8 performs rotation of the spindles 26 and thus causes the thread rolls 22 to move into or out of engagement with a workpiece entered through the aperture 21 in the front plate 18.

A spiral spring 30 is provided within a housing formed within the body part 10 and is anchored at one end to said disc part 10 and at the other end to the shank 3. Said spiral spring is designed so as to tend to rotate the

body parts

9 and 10 considered as a unit, relative to the forward member 8 of the body 4 in a direction which tends to move the thread rolls 22 away from the workpiece. The said spring is also adapted to exert an axially directed force upon the body member 4 as a whole tending to force it along the shank part 3 to cause the body member to be locked to the shank 3 by engagement of dogs 31 on the body part 10 with mating dogs of a projecting flange 32 on the shank portion 3. It will be seen that these dogs serve to hold the

disc parts

9 and 10 in rotary engagement with the shank 3 and that they are held engaged by the axial force derived from the spring 30. While these conditions apply the threading rolls 22 are locked in the working position and can be brought into operative rolling engagement with a workpiece presented at the aperture 21; relative rotation of the head and the workpiece performs progressive rolling of a thread into the surface of the workpiece which thus moves axially into the head until the workstop 5 is engaged. Thereupon locking engagement is released because the body section 4 as a whole moves in the axial direction upon the shank section '3 until the dogs 31 are disengaged from the dogs on the flange 32,whereupon the spring 30 rotates the

parts

9 and 10 of the head relatively to the member 8 and consequently the arms 27 rotate the spindles so that the eccentric portions 23 thereof allow the thread rolls 22 to come out of engagement with the workpiece.

In order to close the rolling head again the

parts

9, 10 are moved back against the spring 30 by means of the hand lever 17 until the dogs 31 are reengaged under the influence of the axial force component of the spring 30.

An alternative construction according to the invention is shown on FIG. 2. In this case the shank section 3 is generally similar to FIG. 1 butis not provided with a flange as at 32 in FIG. 1. The threading rolls 22 are mounted by needle roller bearings 24 on eccentric portions 23 of spindles 25. The latter are journalled at the outer end in -a front plate 18 fastened to spacer blocks 19 by fixing'screws 20. In'this embodiment, however, the body section 4 comprises two cylindrical parts I 35 and 36 which are rotarily adjustable (like the

parts

9 and 10 of FIG., 1) and are held fixed after adjustment by means of stem portions'37 of the spacer, blocks 19 which traverse apertures in the part 35 and have threaded 4, these parts relatively. The rotation of the toothed ring 41 causes rotation of the gear wheels 40 on spindles 25 to disengage the threading rolls 23 from the workpiece. After removal of the workpiece the head can be closed ready for the next thread rolling operation by moving the hand lever 17 until dogs are again engaged, thus locking the head in the working position.

If the rolling head is used as a rotating head and the workpiece is stationary, the opening action is the same without a special rolling head being required. The rolling head according to the invention is therefore suitable without modification for machining a rotating workpiece or a stationary workpiece.

What I claim is:

A self-threading rolling head comprising a housing in which freely rotatable threading rollers are concentrically arranged around the axis of said head, eccentric spindles supporting said rollers, gear members on said spindles, a hollow shank portion adapted to support said head and for mounting in a machine tool, a central gear rotatably mounted on said shank portion and held against axial movement thereon, a stop rod adjustably mounted in said shank for engaging the end of a workpiece after said threading rollers have moved a predetermined distance along said workpiece, a clutch interposed betweenthe housing and said gear, said housing 7 being slidably splined on the end of said hollow shank end parts 38 which traverse arcuate slots in the part 36 and carry clamp nuts 12' as in FIG. 1. Each spindle 25 carries a gear wheel 40 meshing with a central toothed ring 41 forming part of a sleeve 42 which is rotatable upon the shank section 3 but is held from movement in the axial direction by keeprings 43. Part of the sleeve 42 is accommodated with the body part 36 and is coupled permanently to or is integral with a collar 44 from which the operating lever 17 extends. One face of the collar 44 and the adjacent face of the body part'36 are pro,- vided'with disengageable driving dogs.

the shank section 3 so that these parts are relatively slidable in the axial direction but cannot rotate mutual- 1y, Movement in the axial direction occurs when a workpiecebeing threaded engages the workstop 5 and such axial movement produces disengagement of the driving dogs 45 which thus allow a spiral spring 30, arranged in the manner described with reference to FIG. 1, but con- The body part 35 has a splined bore seated upon splined end part of nected to the body part 36 and to the sleeve 42, to rotate and secured against rotation relative thereto and said References Cited'by the Examiner UNITED STATES PATENTS 2,651,224' 9/53 Erdelyi 6 2,720,801 10/55 Eldelyi 806 2,909,078 10/59 Powell 80-6 3,058,196 10/62 Bour 806 WILLIAM J. STEPHENSON, Primary Examiner.

THOMAS E. BEALL, CHARLES W. LANHAM,

Examiners.