# US 2014/0037394 A1 · Die head retaining mechanism

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- Number: US 2014/0037394 A1
- Document ID: US20140037394A1
- Status: Published application
- Kind: A1
- Application number: 13/651,737
- Filed: 2012-10-15
- Published: 2014-02-06
- Earliest claimed: 2012-08-06
- Assignees: Emerson Electric Co.
- Applicants: Emerson Electric Co.
- Inventors: Prasad Chatursingh Patil; Sachin Shashikant Dakare; Richard M. Kundracik
- Web page: https://patentgrep.com/patent/US20140037394A1

## CPC

- B23G 1/04: Machines with one working-spindle
- B23B 31/16004: {Jaws movement actuated by one or more spiral grooves}
- B23G 1/24: portable
- B23G 1/46: for holding the threading tools {(B23B31/083 takes precedence)}
- B23G 2240/44: Tap or die wrenches with multiple locations for holding threading tools, e.g. for holding threading tools of different sizes
- Y10T 408/95: with tool-retaining means
- Y10T 408/953: Clamping jaws
- B23G: THREAD CUTTING; WORKING OF SCREWS, BOLT HEADS, OR NUTS, IN CONJUNCTION THEREWITH (making helical grooves by turning B23B5/48, by milling B23C3/32, by forging, pressing, or hammering B21K1/56, by grinding B24B19/02; arrangements for copying or controlling B23Q; thread-forming by corrugating tubes B21D15/04, by rolling B21H3/02)
- B23B: TURNING; BORING (arrangements for copying or controlling B23Q)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A die head retaining mechanism for installing or removing a die head in a power drive for thread cutting operations is described. The mechanism comprises a cam and follower arrangement with a face gear having at least one locking jaw disposed in a slot provided on the face of the face gear oriented away from the housing. The mechanism also comprises a drive ring having a collection of cam profiles to control the movement of the locking jaws. The mechanism also comprises at least one compression spring disposed in corresponding groove(s) on the face gear. The compression spring is typically preloaded to keep the locking jaws in a locked position. The mechanism also comprises a bearing provided between the housing and the face gear. The bearing is locked in place by a retaining ring. A locking plate, spring washers, and screws are used to secure the assembly of the die head retaining mechanism on the power drive.

## Claims

### Claim 1

A power drive for performing thread cutting operations, the power drive comprising:
a housing;
a face gear disposed in the housing with a plurality of slots and at least one groove;
a die head retaining mechanism, the die head retaining mechanism comprising:
at least one locking jaw;
at least one compression spring;
a drive ring having a plurality of cam profiles and means to compress the spring(s);
a die head disposed in the die head retaining mechanism;
wherein the die head retaining mechanism is disposed between the face gear and the die head for installing or removing the die head in the power drive, each of the at least one locking jaws is disposed in a respective slot provided on the face gear and engaged with at least one of the cam profiles of the drive ring, and the at least one compression spring is disposed in the at least one groove in the face gear and adapted to be compressed during rotation of the drive ring to allow the locking jaws to follow the cam profiles to move outward in a radial fashion to open or unlock the die head from the power drive.

### Claim 2 (depends on 1)

The power drive of claim 1 further comprising a locking plate and a plurality of clamping means for engagement to the drive ring.

### Claim 3 (depends on 2)

The power drive of claim 2, wherein the clamping means comprise a plurality of spring washers and screws for engaging the die head retaining mechanism on the face gear.

### Claim 4 (depends on 1)

The power drive of claim 1 further comprising a bearing and a retaining ring, wherein the bearing is disposed between the housing and the face gear and the bearing is retained by the retaining ring in a groove in the housing.

### Claim 5 (depends on 1)

The power drive of claim 1, wherein the face gear accommodates three equidistant locking jaws in three slots provided on a face of the face gear oriented away from the housing, the face gear further including at least one circumferential groove for accommodating a preloaded compression spring, wherein during an anticlockwise rotation of the drive ring, the compression spring is compressed to allow the locking jaws to follow the cam profiles of the drive ring and move outward in a radial direction to open or unlock the die head from the power drive.

### Claim 6 (depends on 1)

The power drive of claim 1, wherein the compression spring is preloaded by insertion into the at least one groove in the face gear and during operation, the compression spring abuts one end in the groove and is constrained by a lug of the drive ring at the other end; the lug protrudes from the drive ring into a corresponding recess or slot provided on the face gear, to allow the compression spring to be compressed, and the locking jaws to move outward in a radial direction, and unlock the die head from the power drive.

### Claim 7 (depends on 1)

The power drive of claim 1, wherein a lug protrudes from the drive ring and engages one end of the compression spring to compress the compression spring and the other end of the compression spring is engaged in a groove provided on the face gear, in order for the at least one locking jaw to move outward in a radial direction to disengage the at least one locking jaw from the die head.

### Claim 8 (depends on 1)

The power drive of claim 1 wherein the drive ring is provided with a gripping area defined with circumferentially defined pits and peaks for gripping the drive ring in any orientation for rotation thereof.

### Claim 9

A die head retaining assembly comprising:
a face gear defining an open interior, a first mating face, a second oppositely directed face, and a plurality of radially directed slots on the first mating face;
a drive ring defining an open interior, a first mating face and a second oppositely directed face, the first mating face of the drive ring directed toward the first mating face of the face gear, the drive ring also defining a plurality of arcuate cams along the first mating face of the drive ring;
a plurality of locking jaw inserts disposed between the first mating face of the face gear and the first mating face of the drive ring, each of the locking jaw inserts being slidably disposed in a respective one of the plurality of radial slots on the first mating face of the face gear and in camming engagement with a respective one of the plurality of arcuate cams along the first mating face of the drive ring;
wherein upon rotation of one of the face gear and the drive ring relative to the other, each of the plurality of locking jaw inserts are radially displaced.

### Claim 10 (depends on 9)

The die head retaining assembly of claim 9 further comprising:
a biasing member disposed between the first mating face of the face gear and the first mating face of the drive ring, the biasing member in engagement with both of the face gear and the drive ring such that the biasing member applies a rotational bias between the face gear and the drive ring.

### Claim 11 (depends on 10)

The die head retaining assembly of claim 10 wherein the face gear defines an arcuate groove and endwall along the first mating face of the face gear, the drive ring includes a lug projecting from the first mating face of the drive ring, and the biasing member is a spring disposed in the arcuate groove and extending between the endwall in the face gear and the lug of the drive ring.

### Claim 12 (depends on 9)

The die head retaining assembly of claim 9 further comprising:
at least one of a bearing and a retaining ring disposed between the face gear and the drive ring.

### Claim 13 (depends on 9)

The die head retaining assembly of claim 9 wherein the plurality of locking jaw inserts are three in number.

### Claim 14 (depends on 9)

The die head retaining assembly of claim 9 wherein the plurality of slots on the first mating face of the face gear are located circumferentially equidistant from one another.

### Claim 15 (depends on 9)

The die head retaining assembly of claim 9 wherein each of the plurality of locking jaw inserts includes an inwardly and radially directed extension adapted to engage a recess defined along an outer region of a die head to be retained by the die head retaining assembly.

### Claim 16

A system for radially engaging a removable die head, the system comprising:
a face gear adapted to receive a rotary drive force to thereby rotate the face gear about its center, the face gear defining an open interior region and a first mating face and at least one slot defined on the first mating face;
at least one locking jaw insert, each locking jaw insert slidably disposed in a corresponding slot of the at least one slot defined on the first mating face of the face gear;
a drive ring defining a center, an open interior region, a first mating face, and at least one cam defined on the first mating face of the drive ring;
wherein the first mating face of the drive ring and the first mating face of the face gear are directed toward one another, and the face gear and the drive ring are aligned with each other such that the center of the face gear is collinear with the center of the drive ring, and the at least one locking jaw insert is slidably disposed in the at least one slot defined on the first mating face of the face gear and in camming engagement with the at least one cam defined on the first mating face of the drive ring.

### Claim 17 (depends on 16)

The system of claim 16 wherein upon rotation of one of the face gear and the drive ring relative to the other, the at least one locking jaw insert is radially displaced in the corresponding slot of the face gear.

### Claim 18 (depends on 16)

The system of claim 16 wherein at least one of the face gear and the drive ring define an arcuate groove on their corresponding first mating faces, the system further comprising:
a lug projecting from the first mating face of one of the face gear and the drive ring, the lug positioned so as to be accessible from the arcuate groove;
a biasing member disposed in the arcuate groove and in engagement with the lug.