# US 12,768,271 B2 · Carbon fiber rock bolt

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- Number: US 12,768,271 B2
- Document ID: US12768271B2
- Status: Granted
- Kind: B2
- Application number: 18/283,756
- Filed: 2022-03-23
- Published: 2024-05-30
- Granted: 2026-10-20
- Earliest claimed: 2021-03-23
- Assignees: CMTE Development Limited
- Applicants: Cmte Development Limited
- Inventors: Karsten Hoehn; Scott Barnes
- Web page: https://patentgrep.com/patent/US12768271B2

## CPC

- E21D 21/006: {Anchoring-bolts made of cables or wires}
- E21D 20/02: with provisions for grouting
- E21D 21/0006: {characterised by the bolt material}
- E21D 21/008: {Anchoring or tensioning means}
- E21D 21/02: having means for indicating tension (screwed connections specially modified for indicating tensile load F16B31/02)
- 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 carbon fiber rock bolt including: an outer carbon fiber rope including a series of tow fibers; and an inner core material. As the tension on the rock bolt increases beyond a predetermined limit, the inner core material undergoes a spatial compression, whilst the angle of twist in the carbon fiber rope strands decreases, resulting in extension of the carbon fiber rock bolt, replicating the ductility seen in steel rock bolts.

## Claims

### Claim 1

A carbon fiber rock bolt including:
an outer carbon fiber rope comprising a series of tow fibers;
an inner core material; and
wherein as the tension on the rock bolt increases beyond a predetermined limit, the inner core material undergoes a spatial compression
wherein said inner core includes a honeycomb like structure having a series of cavities.

### Claim 2 (depends on 1)

A carbon fiber rock bolt as claimed in claim 1, wherein said carbon fiber rope is impregnated with a high extension resin.

### Claim 3 (depends on 2)

A carbon fiber rock bolt as claimed in claim 2, wherein the degree of extension of the resin is at least 20%.

### Claim 4 (depends on 3)

A carbon fiber rock bolt as claimed in claim 3, wherein the degree of extension of the resin is about 130%.

### Claim 5 (depends on 1)

A carbon fiber rock bolt as claimed in claim 1, wherein said carbon fiber rope includes at least one pressure sensitive optical fiber axially formed in the rope.

### Claim 6 (depends on 1)

A carbon fiber rock bolt as claimed in claim 1, wherein the fiber is anchored to a surface using one of a resin capsule, pumpable resin or a mechanical anchor.

### Claim 7 (depends on 1)

A carbon fiber rock bolt as claimed in claim 1, further including a tensioning member at one end.

### Claim 8 (depends on 7)

A carbon fiber rock bolt as claimed in claim 7, wherein said tensioning member includes one of a torque tensioning member, a hydraulic ramp, a rig mast or cable drum arrangement, or an expandable foam or core.

### Claim 9 (depends on 1)

A carbon fiber rock bolt as claimed in claim 1, wherein said cable is terminated using either an encapsulation sleeve or socket arrangement, a wedge locking arrangement, a swaged sleeve or thimble arrangement, or a wire grip type member.

### Claim 10 (depends on 1)

A carbon fiber rock bolt as claimed in claim 1, wherein the direction of twist of adjacent carbon fiber filaments is alternated.