# US 5,345,685 A · Strata movement indicator

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- Number: US 5,345,685 A
- Document ID: US5345685A
- Status: Granted
- Kind: A
- Application number: 08/080,511
- Filed: 1993-06-24
- Granted: 1994-09-13
- Earliest claimed: 1992-07-15
- Assignees: Coal Industry (Patents) Limited
- Inventors: Alan S. Bloor
- Web page: https://patentgrep.com/patent/US5345685A

## CPC

- G01B 5/30: for measuring the deformation in a solid, e.g. mechanical strain gauge
- G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS

## Abstract

A strata movement indicator includes at least two lengths of suspension wire respectively for remote and near anchors locatable in the same borehole. Each wire carries a cylinder provided with indicator markings, the cylinders being moveable with respect to one another and to a reference tube fixed in the mouth of the borehole. Relative movement of the cylinders with respect to one another and/or to the reference tube indicates the degree of strata movement.

## Claims

### Claim 1

A strata movement indicator for use in association with a borehole formed in strata, the indicator including at least two flexible elongate suspension members, anchors for anchoring the suspension members at spaced apart locations in use within the borehole formed, a guide through which the members pass, the guide being fixable in use within the borehole, and a cylindrical indicator element held on each suspension member and movable in relation to the guide and to one another in the manner of a piston, the movement of each element being indicative of strata movement.

### Claim 2 (depends on 1)

An indicator according to claim 1 in which each flexible elongate suspension member is a length of wire cable.

### Claim 3 (depends on 1)

An indicator according to claim 1 in which each anchor is a wire torsion spring engageable directly with the wall of the borehole.

### Claim 4 (depends on 1)

An indicator according to claim 1 in which the guide is a short tubular sleeve extending in use a short distance within the borehole.

### Claim 5 (depends on 4)

An indicator according to claim 4 in which the sleeve is split longitudinally thereof and is in use sprung into the borehole and frictionally fixed therein.

### Claim 6 (depends on 1)

An indicator according to claim 1 in which each indicator element is marked to indicate the degree of movement relative to the guide.

### Claim 7 (depends on 6)

An indicator according to claim 6 in which each indicator element is marked with chromatic banding.

### Claim 8 (depends on 1)

An indicator according to claim 1 in which the cylindrical indicator element on one suspension member is mounted to slide within the cylindrical indicator element of the other suspension member.