Key information

Title
COMBINATION ROCK BOLT AND METHOD FOR ITS MANUFACTURE
Application number
20200478
Case type
National
Status
03.12.2023 P.g.a ikke betalt meddelesesavgift. Søker har ikke begjært gjenopptakelse
Filed
21.04.2020
Effective date
21.04.2020
Publicly available
22.10.2021
Applicant
SMS TECH HOLDING AS (NO)
Inventor
Jatinder Pal Singh Sandhu (NO)
Agent
CURO AS (NO)

Abstract and drawing

Disclaimer: This text has been machine-scanned and may contain errors – please refer to "Publications" for legally binding content.
Combination rock bolt (10) comprising an elongate bolt member (11) provided with an expansion shell (12) at an inner end (13) and a tightening nut (14) and retaining washer (16) at an outer end (17), as well as means to introduce a cement slurry from the inner end towards the outer end. A tube (18) is arranged separately and externally in relation to the bolt member (11) for introducing cementing grout. The tube is attached to the bolt member by means of a plurality of spacer plates (19) provided with through openings or recesses (21, 22) adapted to the diameter of the bolt member (11) and the tube (18) respectively. A method for manufacture of the combination rock bolt is also contemplated.

Publications

A1
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Documents

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Date
 Date Doc. No. Process Case number In/Out Journal description To/from
 10.04.2024 18-01 Saksbehandling 20200478 UT Endelig henleggelse ENG CURO AS
 11.12.2023 17-01 Saksbehandling 20200478 UT Henlegg meddelelse CURO AS
 03.10.2023 16-01 Saksbehandling 20200478 UT Intention to grant CURO AS
 25.05.2023 15-07 Saksbehandling 20200478 INN NO20200478 reply 2305 CURO AS
 25.05.2023 15-06 Saksbehandling 20200478 INN NO20200478 NO krav 2305 CURO AS
 25.05.2023 15-05 Saksbehandling 20200478 INN NO20200478 description 2305 clean CURO AS
 25.05.2023 15-04 Saksbehandling 20200478 INN NO20200478 description 2305 annot CURO AS
 25.05.2023 15-03 Saksbehandling 20200478 INN NO20200478 claims 2305 clean CURO AS
 25.05.2023 15-02 Saksbehandling 20200478 INN NO20200478 claims 2305 annot CURO AS
 25.05.2023 15-01 Saksbehandling 20200478 INN Korrespondanse (Hovedbrev inn) CURO AS
 12.04.2023 14-02 Saksbehandling 20200478 INN 20200478_søknad om fristforlengelse CURO AS
 12.04.2023 14-01 Saksbehandling 20200478 INN Korrespondanse (Hovedbrev inn) CURO AS
 12.01.2023 13-01 Saksbehandling 20200478 UT 20200478_1661673_PT 08 Eng CURO AS
 01.12.2022 12-01 Saksbehandling 20200478 INN Korrespondanse (Hovedbrev inn) CURO AS
 16.08.2022 11-04 Saksbehandling 20200478 INN NO20200478 Reply 2208 CURO AS
 16.08.2022 11-03 Saksbehandling 20200478 INN NO20200478 claims 2208 clean CURO AS
 16.08.2022 11-02 Saksbehandling 20200478 INN NO20200478 claims 2208 annot CURO AS
 16.08.2022 11-01 Saksbehandling 20200478 INN Korrespondanse (Hovedbrev inn) CURO AS
 01.06.2022 10-01 Saksbehandling 20200478 UT 20200478_1580134_PT 08 Eng CURO AS
 27.04.2022 09-01 Saksbehandling 20200478 UT Generelt brev Patent CURO AS
 29.03.2022 08-02 Saksbehandling 20200478 INN NO_20200478 CURO AS
 29.03.2022 08-01 Saksbehandling 20200478 INN Korrespondanse (Hovedbrev inn) CURO AS
 28.02.2022 07-01 Saksbehandling 20200478 UT PT Varsel om betaling av første årsavgift (3317) (PT20200478)
26.04.2021 06-04 Saksbehandling 20200478 INN NO20200478 Reply 2104 CURO AS
 26.04.2021 06-03 Saksbehandling 20200478 INN NO20200478 claims 2104 clean CURO AS
 26.04.2021 06-02 Saksbehandling 20200478 INN NO20200478 claims 2104 annot CURO AS
 26.04.2021 06-01 Saksbehandling 20200478 INN Korrespondanse (Hovedbrev inn) CURO AS
 21.11.2020 05-02 Saksbehandling 20200478 UT PT report 08:51:41
21.11.2020 05-01 Saksbehandling 20200478 UT Substantive examination CURO AS
 08.05.2020 04-03 Saksbehandling 20200478 INN Overdragelsesdokument CURO AS
 08.05.2020 04-02 Saksbehandling 20200478 INN Fullmakt CURO AS
 08.05.2020 04-01 Saksbehandling 20200478 INN Korrespondanse (Hovedbrev inn) CURO AS
 23.04.2020 03-01 Saksbehandling 20200478 UT Formal Examination 1 CURO AS
 23.04.2020 02-01 Saksbehandling 20200478 UT Information to inventor CURO AS
 21.04.2020 01-03 Saksbehandling 20200478 INN Patenttegninger CURO AS
 21.04.2020 01-02 Saksbehandling 20200478 INN Beskrivelse CURO AS
 21.04.2020 01-01 Saksbehandling 20200478 INN Søknadsskjema Patent CURO AS

Description, claims and drawings

Disclaimer: This text has been machine-scanned and may contain errors – please refer to "Publications" for legally binding content. Description
Combination rock bolt and method for its manufactureThe present invention concerns a combination rock bot as indicated by the preamble of clam 1. According to a further aspect, the invention concerns the manufacture of a combination rock bot as indicated by the preamble of claim 9.BackgroundRock bolts have typically been corrosion protected in one or more ways, e.g. by being hot galvanized and/ or powder painted. When completely embedded in cement compositions, the need for other corrosion protection has diminished.US 4655644 (1984) concerns a rock bolt comprising a sleeve having at least one port near its upper end, and a central member axially disposed, and extending substantially the length of, the sleeve. The central member defines an annular chamber in the sleeve, reducing the amount of binder required and acting as a structural member. At least one port is provided in the lower part of the sleeve for the introduction of binder under pressure. The bolt furthermore comprises an expander member that on installation is caused to expand to engage the walls of the borehole in which it is installed.US 5636945 A (1992) describes a rock bolt comprising a tube that surrounds the bolt over the greater part of its free length. On installation into a bore hole, a cementing grout will be pumped through the tube and fill the borehole from inside out, thereby expelling the air therein. The bolt is provided with an expansion bushing at its inner end, to provide a first and preliminary attachment in the rock. Tightening a nut at the free, outer end of the bolt, makes the expansion bushing expand.US 2001046418 A1 (2001) shows another design of a tube shaped rock bolt, also intended for being permanently attached in a borehole by means of a cementing composition to be injected through the inner of the rock bolt. The main difference from US 5636945 A is that the bolt itself is hollow and does not need a separate tube for the injection of the cementing grout. The bolt design of US 2001046418 A1 also shows an expansion element at its inner end, here called an anchor.While a number of improvements have been made over the recent years related to safety in tunnels and mines, and in particular related to rock bolts, the number and dimensions required to reach an acceptable safety level are such that further improvements still are required in order to obtain a satisfactory safety level at an acceptable cost. The global, yearly production of rock bolts is in the magnitude of 500 million bolts. It is a general requirement (when used in road tunnels and mines) that the bolts shall endure a linear elastic extension of at least 8 % according to internationally accepted standards.ObjectiveIt is an objective to provide a rock bolt that fulfils all safety requirements for use in tunnels and mines and which is more cost-efficient than existing rock bolts.The present inventionThe above mentioned objectives are achieved by the combination rock bot according to the present invention as defined by claim 1.According to a further aspect the present invention provides a method for the manufacture of a combination rock bolt as defined by claim 9.The combination rock bot according to the present invention is 5-10% lighter than existing combination rock bots and exhibits a ductility allowing an elastic extension of at least 12 %, more typically at least 15 % and 18 %. The improved ductility allows use of less material per meter bolt, which is the cause of the savedBy the term “cementing grout” as used herein is understood any flowable binding composition with a viscosity allowing injection through the pipe described with the ability to set and form a sufficient binding between the rock bolt and bore hole wall. The cementing grout included hydraulic based cements and polymer binders in a wide variety of compositions.The bolt typically has a diameter of 20 mm while the inner tube diameter typically is about 12 mm. Bolts are also provided with diameter up to at least 33 mm, such as M20, M22, M25, and M33. Typically, but not mandatory, the bolts are provided with hot dip galvanize carried out in compliance with NS -EN ISO 1461 and Epoxy powder coating in compliance with NS EN 13438. Bolts can be also produced in Stainless Steel class A4-80 and/ or epoxy powder coating in compliance with NS EN 13438.The objective of the present invention is fulfilled in that all safety issues related to the combination rock bot of the present invention and the use thereof, is maintained at least at the same level as with prior art rock bolts, while the elastic extension is improved and the weight reduced.Below the present invention is described in further detail in the form of an exemplifying embodiment illustrated by the enclosed drawings. Figure 1 is a schematic side view of a combination rock bot according to the present invention. Figure 2 is a schematic view of a detail of the combination rock bot according to Fig.1Figure 3 is a schematic end view of the combination rock bot according to Fig.1.Figure 1 shows a combination rock bot 10 according to the present invention, comprising a bolt 11 with a front or inner end 13 and a back or outer end 17. The combination rock bot exhibits an expansion shell 12 at its inner end, arranged to be expanded by tightening the nut 14 provided at the outer end. A grouting tube 18 for injection of a cementing grout is arranged in parallel with the bolt 11, held in place by means of a number of brackets 19. A retaining washer 16 with a comparatively large diameter is arranged inside the nut 14 with a coned or half-round washer 15 in between. The retaining washer engages the rock wall tightly when the nut 14 is tightened, due to a modest shortening of the rock bolt as a consequence of the tightening action. Due to this action, the retaining washer is also commonly denoted a pressure washer. Coned washer or half round washer is also helpful to mount the rock bolt up to 30° angle from the head of the bolt. The grouting tube 18, typically having an inner diameter of about 12 mm, contributes to the weight of the combination rock bot in a much smaller extent than tubes formed coaxially around the bolt member. The grouting tube 18 is arranged through the retaining washer 16 and has an inlet end 18a connectable to a system for providing cementing grout. The outlet end 18b of the grouting tube 18 is positioned near the expansion shell 12, thereby allowing grout injected through the grouting tube 18 to fill the borehole from its inner end towards its outer end, while expelling the air therefrom.Figure 2 shows a configuration of the bracket 19, cold pressed onto the bolt 11 and welded to the grouting tube 18. The brackets 19 are made in a harder, less ductile metal than the bolt member 11, and serve as rigid anchoring points against the borehole wall as soon as the grout filled into the cavity between the bolt and the borehole wall has set and hardened. Cold pressed brackets absorb the energy in the situation of deforming or sudden burst and slower the deforming or sudden burst due to high level of elongation present in the material.The attachment between brackets 19 and bolt member 11 needs to be sufficiently firm so that the axial position of the brackets are neither affected by the insertion of the combination rock bot into a borehole nor by the movement of the grout which will flow past the brackets. Typically, the brackets 19 are cold pressed onto the bolt member 11 subsequent galvanization of both parts. Any means effective to secure the brackets 19 to the bolt member 11 may be used, mechanically as well as chemically, hereunder gluing, brazing, welding, frictional forces, provision of grooves in the surface of the bolt member or lugs extending therefrom, etc. Cold pressing is a preferred method due to the fact that it is reliable, fast and inexpensive.Correspondingly, the attachment between the brackets 19 and the tube 18 should be sufficiently firm to ensure that the grouting tube 18 maintains its relative axial position to the bolt member during and after the insertion of the combination rock bot into a borehole. Typically, the brackets 19 are welded onto the tube 18, the weld shown as item 21 in Figure 2 and the combined tube plus brackets thereafter galvanized before bring attached to the bolt member 11.Figure 3 is an end view of the combination rock bot 10 from its outside, showing the bolt member 11, the nut 14, the retaining washer 16, the inlet end of the grouting tube 18 and a bleeder hole 31 through the retaining plate, through which excess grout is expelled when the bore hole has been completely filled.The use of the combination rock bot according to the present invention is more or less the same as with priory known rock bolts. However, since the grouting tube 18 for the grout is not surrounding the bolt member, there is no need to connect a grout-providing device via a particularly designed grout head, instead it may be connected directly to the tube end 18a. Thereby, additional weight is avoided.ExampleTests performed by an independent organisation gave the following data for an embodiment of the combination rock bolts according to the present invention.A bolt of diameter 20 mm, cross-section 314 mm2, thus has a yield strength of 165000 Newton
Claims
Claims1. Combination rock bolt (10) comprising an elongate bolt member (11) provided with an expansion shell (12) at an inner end (13) and a tightening nut (14) and retaining washer (16) at an outer end (17), as well as a member to introduce a cementing grout from the inner end towards the outer end, characterized in that the member to introduce the cementing grout has the form of a grouting tube (18) arranged separately and externally in relation to the bolt member (11), attached to the bolt member by means of a plurality of brackets (19) which are adapted to the diameter of the bolt member (11).2. Combination rock bolt (10) according to claim 1, wherein the grouting tube (18) is arranged in parallel with the bolt member (11).3. Combination rock bolt (10) according to any preceding claim, wherein each bracket (19) is welded to the grouting tube (18).4. Combination rock bolt (10) according to any preceding claim, wherein each bracket (19) is cold pressed onto the bolt member (11).5. Combination rock bolt (10) according to any preceding claim, wherein the bolt member (11) is galvanized before before being combined with the grouting tube (18).6. Combination rock bolt (10) according to any preceding claim, exhibiting a ductility ensuring a maximal elastic extension of at least 12%, more preferred at least 15% and most preferred about 18%.7. Combination rock bolt (10) according to any preceding claim, wherein the grouting tube (18) is made in steel.8. Combination rock bolt (10) according to any preceding claim, having a diameter between 20 and 33 mm.9. Method for the manufacture of a combination rock bolt comprising:- providing a bolt member (11) of predetermined length and diameter exhibiting a tightening nut (14) and a retaining washer (16) at its outer end (13) and an expansion shell (12) at its inner end (17), characterised in- providing a separate grouting tube (18) of predetermined length and diameter, attaching brackets (19) at intervals along the length of the grouting tube, and- attaching the brackets (19) to the bolt member (11) to permanently attach the grouting tube (18) to the bolt member (11).10. Method as claimed in claim 9, wherein the brackets (19) are attached to the grouting tube (18) by welding.11. Method as claimed in claim 9 or 10, wherein the brackets (19) are attached to the bolt member (11) by cold pressing.12. Method as claimed in any one of claims 9 to 11, wherein the grouting tube (18) with welded brackets (19) is galvanized before being attached to the bolt member (11).13. Method as claimed in any one of claims 9 to 11, wherein the bolt member (11) is galvanized before being attached to the grouting tube (18).
Drawings

Priority

No priority

Patent classes

IPC classesE21D 20/02CPC classesE21D 20/02

Citations

AU 2020195 A (A)CN 1737270 A (A)US 3379019 A (A)WO 2010/128943 A1 (A1)

Applicants, owners and inventors

Applicants
SMS TECH HOLDING AS
Tyriveien 46 B 1900 FETSUND NO (LILLESTRØM Municipality, Akershus county)Org. number: 921672136Inventors
Jatinder Pal Singh Sandhu
Tyriveien 46 B 1900 FETSUND NO (LILLESTRØM Municipality, Akershus county)

Agent

CURO AS
CURO AS

Org. number: 936803911

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Vestre Rosten 81 7075 TILLER NO (TRONDHEIM Municipality, Trøndelag county)
Org. number: 936803911
Reference: P20200478NO

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