# US 10,370,968 B2 · Friction bolt > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,370,968 B2 - Document ID: US10370968B2 - Status: Granted - Kind: B2 - Application number: 15/779,536 - Filed: 2016-11-25 - Published: 2018-12-06 - Granted: 2019-08-06 - Earliest claimed: 2015-11-30 - Assignees: Sandvik Intellectual Property AB - Applicants: Sandvik Intellectual Property AB - Inventors: Mieczyslaw Rataj; Peter Young; Bradley Darlington - Web page: https://patentgrep.com/patent/US10370968B2 ## CPC - E21D 21/004: {Bolts held in the borehole by friction all along their length, without additional fixing means} - E21D 21/0026: {characterised by constructional features of the bolts} - E21D 21/0033: {having a jacket or outer tube} - E21D 21/006: {Anchoring-bolts made of cables or wires} - E21D 21/0086: {Bearing plates} - E21D 21/008: {Anchoring or tensioning means} - 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 friction bolt assembly to frictionally engage a bore formed in rock strata includes an elongate tube and an expander mechanism acted on by an anchor mechanism via an elongate bar or cable. A retainer mechanism is mounted to act between the bar or cable and the tube to prevent ejection of the bar or cable from the assembly should the bar or cable break. ## Claims ### Claim 1 A friction bolt assembly arranged to frictionally engage an internal surface of a bore formed in rock strata, the assembly comprising: an elongate tube having a leading end and a trailing end; an expander mechanism located within the tube and towards or at the leading end and configured to apply a radial expansion force to the tube to secure the assembly to the rock strata; an elongate bar or cable extending longitudinally within the tube and connected at or towards a first end to the expander mechanism and at or towards a second end to an anchor mechanism positioned at or towards the trailing end of the tube; a retainer mechanism acting between the tube and the bar or cable, the retainer mechanism including a sustainer attached at or towards the trailing end of the tube and an engager provided at the bar or cable axially intermediate the sustainer and the first end of the bar or cable, wherein the engager is configured to engage radially the sustainer to prevent ejection of at least a length portion of the bar or cable from the assembly should the bar or cable break; and the anchor mechanism including a fixing mountable at or towards the second end of the bar or cable and configured to brace against the trailing end of the tube that by adjustment creates tension in the bar or cable to act on the expander mechanism to create the radial expansion force, wherein at least a part of the fixing projects radially outward beyond the tube or a component attached to an external region of the tube to be braced against the rock strata at a region around an external end of the bore. ### Claim 2 (depends on 1) The assembly as claimed in claim 1, wherein the fixing includes a nut and a flange extending radially outward beyond the tube, the flange being configured to be braced against the rock strata. ### Claim 3 (depends on 2) The assembly as claimed in claim 2, wherein: the flange and the nut are formed non-integrally; the nut is coupled directly to the bar or cable; and the flange is positioned axially between the nut and the trailing end of the tube. ### Claim 4 (depends on 2) The assembly as claimed in claim 2, wherein the flange includes an abutment extending radially outward from the tube and having at least a portion facing generally towards the leading end of the tube, the abutment surface being arranged to be engaged by a rock plate to extend radially outward from the flange and to brace against the rock strata at the region around the external end of the bore. ### Claim 5 (depends on 4) The assembly as claimed in claim 4, wherein a distance by which the flange extends radially outward from the tube is approximately equal to or greater than a distance by which the flange extends radially inward between the tube and the bar or cable. ### Claim 6 (depends on 4) The assembly as claimed in claim 4, wherein a distance by which the flange extends radially outward from the tube is greater than half a radial thickness of the bar or cable. ### Claim 7 (depends on 2) The assembly as claimed in claim 2, further comprising a rock plate arranged to abut against and extend radially outward from the flange to brace against the rock strata at the region around the external end of the bore. ### Claim 8 (depends on 1) The assembly as claimed in claim 1, wherein the retainer mechanism further includes a restrainer positioned radially between the bar and an inner surface of the tube, the engager being configured to engage radially the restrainer and the restrainer is configured to engage radially the sustainer to prevent ejection of the bar or cable from the assembly should the bar or cable break. ### Claim 9 (depends on 8) The assembly as claimed in claim 8, wherein the restrainer is a collar having a central bore arranged to receive the bar or cable. ### Claim 10 (depends on 9) The assembly as claimed in claim 9, wherein the restrainer is formed as a single component. ### Claim 11 (depends on 9) The assembly as claimed in claim 9, wherein the restrainer is formed as a component having two parts, the two parts being divided axially. ### Claim 12 (depends on 9) The assembly as claimed in claim 9, wherein the restrainer includes a barb projecting radially outward beyond the tube to engage the sustainer mounted radially externally at the tube. ### Claim 13 (depends on 8) The assembly as claimed in claim 8, wherein the restrainer includes a radially inward facing conical or tapered surface arranged to be engaged by the engager. ### Claim 14 (depends on 8) The assembly as claimed in claim 8, wherein the restrainer includes a notch formed in a radially outward facing surface of the restrainer to receive radially at least a part of the sustainer. ### Claim 15 (depends on 8) The assembly as claimed in claim 8, wherein the restrainer is formed as a single component which is split longitudinally to enable the restrainer to radially expand and contract. ### Claim 16 (depends on 8) The assembly as claimed in claim 8, wherein the sustainer includes a band or ring attached to the tube and engageable radially with at least part of the engager or the restrainer. ### Claim 17 (depends on 1) The assembly as claimed in claim 1, wherein the engager includes ribs protecting radially outward from the bar or cable. ### Claim 18 (depends on 1) The assembly as claimed in claim 1, wherein the engager includes a wedge or ferrule attached to the bar or cable. ### Claim 19 (depends on 1) The assembly as claimed in claim 1, wherein the sustainer includes a tab projecting radially inward from the tube. ### Claim 20 (depends on 1) The assembly as claimed in claim 1, wherein the tube includes a split extending longitudinally and arranged for radial expansion and contraction. ### Claim 21 (depends on 1) The assembly as claimed in claim 1, wherein the sustainer includes a bridge tab secured across the split at or towards the trailing end of the tube, the bridge tab having a portion that is bent radially inward to extend within the tube towards the bar of cable.