# US 5,341,889 A · Ring clamp for a cutter ring in a tunnel drilling machine

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- Number: US 5,341,889 A
- Document ID: US5341889A
- Status: Granted
- Kind: A
- Application number: 07/940,880
- Filed: 1992-10-21
- Granted: 1994-08-30
- Earliest claimed: 1992-10-21
- Assignees: Stein Narvestad A.S.
- Inventors: Stein Narvestad
- Web page: https://patentgrep.com/patent/US5341889A

## CPC

- E21B 10/20: characterised by detachable or adjustable parts, e.g. legs or axles
- E21B 10/12: with discs cutters
- E21D 9/104: {Cutting tool fixtures (devices with percussive tools E21D9/106)}
- E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21D: SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS (soil-conditioning or soil-stabilising materials C09K17/00; drilling or cutting machines for mining or quarrying E21C; safety devices, transport, rescue, ventilation or drainage E21F)

## Abstract

A cutter for a tunnel boring machine with cutter ring in two or more ring segments with a dovetail base, clamped to the cutter hub by a segmented clamping ring. The ring segments have a wedge shaped cross section, and are mounted in a groove. The segments are fastened to the hub by bolts. To facilitate loosening of the ring segments, the segments have a curvature different from that of the groove, so that an elastic force will be accumulated in the ring segments when they are mounted and the bolts are tightened. The curvature of the ring segments is either smaller or greater than that of the groove.

## Claims

### Claim 1

A ring clamp for securing a cutter ring to a cutter ring in a tunnel boring machine, the cutter ring comprising at least two segments having a dovetail shaped base and a ring clamp having a corresponding wedge shape comprising at least two segments whereby the segments are secured to the roll by means of bolts, wherein the curvature of the segments is different from the curvature of a groove in which the segments of the ring clamp are secured.

### Claim 2 (depends on 1)

The ring clamp according to claim 1, wherein the segments are adapted for securement by means of one bolt at each end of the segment such that each bolt clamps the ends of adjacent segments.

### Claim 3 (depends on 1)

The ring clamp according to claim 1, wherein the segments being adapted for securement by means of at least two bolts.

### Claim 4 (depends on 1)

The ring clamp according to claim 1, wherein the curvature of the segments is larger than the curvature of the groove.

### Claim 5 (depends on 1)

The ring clamp according to claim 1 wherein the curvature of the segments being smaller than the curvature of the groove.

### Claim 6

A ring clamp for securing a cutter ring to a cutter roll in a tunnel boring machine, the cutter ring comprising at least two segments having a dovetail shaped base and a ring clamp having a corresponding wedge shape comprising at least two segments whereby the segments are secured to the roll by means of bolts, wherein the curvature of the segments is greater than the curvature of a groove in which the segments of the ring clamp are secured, and wherein the segments are adapted for securement by means of one bolt at each end of the segment such that each bolt clamps the ends of adjacent segments.

### Claim 7

A ring clamp for securing a cutter ring to a cutter roll in a tunnel boring machine, the cutter ring comprising at least two segments having a dovetail shaped base and a ring clamp having a corresponding wedge shape comprising at least two segments whereby the segments are secured to the roll by means of bolts, wherein the curvature of the segments is different from the curvature of a groove in which the segments of the ring clamp are secured, and wherein the curvature of the segments is smaller than the curvature of the groove.