AU672428B2 - Hollow bars and method of manufacture - Google Patents
Hollow bars and method of manufactureInfo
- Publication number
- AU672428B2 AU672428B2 AU48116/93A AU4811693A AU672428B2 AU 672428 B2 AU672428 B2 AU 672428B2 AU 48116/93 A AU48116/93 A AU 48116/93A AU 4811693 A AU4811693 A AU 4811693A AU 672428 B2 AU672428 B2 AU 672428B2
- Authority
- AU
- Australia
- Prior art keywords
- members
- rock bolt
- drill rod
- longitudinal edges
- rolling
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Ceased
Links
Description
OPI DATE 26/04/94 APPLN. ID 48116/93 i i AOJP DATE 14/07/94 PCT NUMBER PCT/AU93/00486 1111111 11111 1111 1 1111 Il11111 i II II AU9348116 INTEKIlNA I uiNAL AIrrLIA I IUN IUBiLIIbHhbU UNUEK I HI PA I ENT COOPERATION TREATY (PCT) (51) International Patent Classification 5 International Publication Number: WO 94/07619 B21C 37/06, 37/08, 37/10 Al B21H 8/00 (43) International Publication Date: 14 April 1994 (14.04.94) (21) International Application Number: PCT/AL 3/00486 (81) Designated States: AU, CA, US, European patent (AT, BE, CH, DE, DK, ES, FR, GB, GR, IE, IT, LU, MC, (22) International Filing Date: 22 September 1993 (22.09.93) NL, PT, SE).
Priority data: Published PL 4942 25 September 1992 (25.09.92) AU With international search report.
lT7th amended claims.
(71)Applicant (for all designated States except US): BHP ENGINEERING PTY. LTD. [AU/AU]; 169-185 Miller Street, North Sydney, NSW 2060 (AU).
(72) Inventor; and Inventor/Applicant (for US only) GRAY, Peter, Andrew [AU/AU]; 11 Partridge Place, Fig Tree Heights, NSW 2525 (AU).
(74) Agent: GRIFFITH HACK CO.; 509 St. Kilda Road, Melbourne, VIC 3004 (AU).
(54) Title: HOLLOW BARS AND METHOD OF MANUFACTURE 21b (57) Abstract A hollow bar and a method of manufacturing the hollow bar are disclosed. Typically, the hollow bar is a threaded rock bolt or a drill rod. The hollow bar comprises two or more elongate members (21a, 21b) connected together along the longitudinal edges (41) of the members (21a, 21b). The method comprises rolling the members (21a, 21b) and welding or gluing the members (21a, 21b) together along the longitudinal edges (41) of the members (21a, 21b).
L IIT-I I L _L 1 HOLLOW BARS AND METHOD OF MANUFACTURE The present invention relates to hollow bars, particularly hollow bars that are suitable for use as rock bolts and drill rods, and to a method of manufacturing hollow bars.
A known method, commonly referred to as the "pierced-billet method", of manufacturing hollow drill rods comprises drilling a billet of steel, typically up to 150mm in diameter and 1.2mm in length from both ends to form a 1. 0 hole that is approximately 20-30mm in diameter and inserting a manganese steel mandrel into the hole. The method further comprises heating the billet with the mandrel inside to about 1150 0 C and then passing the billet/mandrel through a series of rolls to form the required transverse section round, square, hexagonal etc) and to reduce the external diameter to the required dimensions. The method further comprises allowing the rolled billet/mandrel to cool and removing the mandrel to form the final product of a rolled steel bar having a central hole and the required external profile and dimensions. In order to remove the mandrel from the rolled billet/mandrel the mandrel is gripped and pulled in tension to reduce its diameter slightly and the mandrel is cut while in tension so that it files out of the billet.
The method involves several steps and also necessitates the use of a special manganese steel for the mandrel which has to be scrapped after being removed from the rolled steel bar. Consequently, the method is relatively expensive and is not suited to large scale production as would be required for rock bolts.
A known method of manufacturing tubes comprises rolling a long, flat strip of steel into a round shape and stafthlley/keep/48116.93_1 31.5.96 1 SS-T I 11 2 then continuously welding the two sides of the strip together to form a tube. In practice, the method is carried out on a continuous basis and the welding is completed very quickly.
The method can produce tubes of different sizes within limits, although it is very difficult to produce a relatively thick walled tube as would be required for rock bolts without the further step of "sinking" the tube through a die to reduce the outside diameter and at the same time to increase the wall thickness. In addition, it i. .is very difficult to roll a profile on the outside of the tube as would be required for rock bolts of the type having an external threaded profile.
It is an object of the present invention to 15 provide a method of manufacturing hollow bars which alleviates the disadvantages of the known methods described 'in the preceding paragraphs.
According to the present invention there is provided a method of manufacturing a rock bolt or a drill 20 rod having an axially extending bore, the method comprising the steps of: rolling or die drawing two of more elongate members each of which forms a segment of the rock bolt or the drill rod and comprises an internal wall and an external wall; and connecting the members together along the longitudinal edges of the members to form the rock bolt or the drill rod with the internal walls of the members definirV the axially extending bore.
staft/hlley/keep/48116.93_1 31.5.96 L II I B 3 The term "hollow bar" as used herein is understood to cover any elongate element, such as hollow rock bolts, drill rods, pipes or tubes.
It is preferred that the method comprises forming two members to form the hollow bar.
It is preferred particularly that the two members be identical.
In one embodiment it is preferred particularly that the step of rolling the members forms sections of a threaded profile on each of the members so that the hollow bar formed by connecting the members together comprises a threaded profile and is suitable for use as a threaded rock bolt.
In another embodiment it is preferred 15 particularly that the step of rolling the members forms a '"half hexagonal shape on each of the members so that the "hollow bar formed by connecting the members together comprises a complete hexagonal profile and is suitable for use as a hexagonal drill rod.
It is preferred thut the method comprises connecting the members together by welding or gluing.
It is preferred that the step of connecting the members together comprises feeding the members into a jig, aligning the members, and welding or gluing the members together.
It is preferred that the step of rolling the members forms the longitudinal edges of the members with profiles to maximise the surface area of contact and enable proper alignment when connecting the members together.
stafMlleylkee/48116.93_1 31.5.96
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II
4 It is preferred particularly that the profiles be tongue and groove profiles.
It is preferred that the step of rolling the members forms the longitudinal edges so that when the members are positioned together the adjacent longitudinal edges define the sides of an outwardly opening channel for receiving weld metal or glue.
According to the present invention there is also provided a rock bolt or a drill rod having an axially 10 extending bore, the rock bolt or the drill rod comprising two or more elongate members formed by rolling or die 9drawing which are connected together along the longitudinal edges of the members, each member having an internal wall and an external wall, and the internal walls defining the 15 axially extending bore.
It is preferred that there be two members.
ooze It is preferred particularly that the two members be identical.
It is preferred that the longitudinal edges of the members comprise profiles that maximise the surface area of contact between the longitudinal edges of adjacent members and enable power alignment of the members.
staff/hlleyI/eep/4811S93_1 31.5.96 WO 94/07619 PCT/AU93/00486 It is preferred particularly that the profiles be tongue and groove profiles.
It is preferred that the members be connected together by welding or gluing.
It is prefaerred that the longitudinal edges of the members define outwardly opening channels for receiving weld metal or glue.
It is preferred that the hollow bar be suitable for use as a threaded rock bolt or a drill rod.
It is preferred particularly that each member comprises an external profile that defines part of the threaded profile of the rock bolt or the drill rod.
The present invention is described further by reference to the accompanying drawings in which: Figure 1 is a side elevation of a preferred embodiment of a self-tapping rock bolt in accordance with the present invention formed by welding together two identical elongate members; Figure 2 is a cross-sectional view along the line A-A in Figure 1 illustrating the cross-sectional profile of a preferred embodiment of the members; Figure 3 is a cross-sectional view similar to that shown in Figure 2 but with the members spaced apart; and Figure 4 is a cross-sectional view along the line I lad, I WO 94/07619 PCT/AU93/00486 6 A-A in Figure 1 illustrating the cross-sectional profile of another preferred embodiment of the members.
The roL.k bolt shown in the figures is of the type disclosed in Figures 7 to 9 in the patent specification of International application PCT/AU91/00503 (W092/08040) in the name of BHP Engineering Pty Ltd.
The rock bolt 3 comprises: a leading end 5 for convenient insertion into a pilot hole (not shown); a trailing end 7; an axially extending bore 9 (which may be circular or non-circular depending on requirements) to enable water to be pumped through the rock bolt into the pilot hole during insertion of the rock bolt 3; two diametrically opposed flats 11 extending along the length of the rock bolt 3; and a plurality of thread sections 13 which form a discontinuous threaded profile.
Typically, the rock bolt 3 has a diameter of to 50mm and a maximum wall thickness of at least As can best be seen in Figures 2 and 4 each thread section 13 extends from a leading edge 17 adjacent to one of the flats 11 to a trailing edge 19 adjacent to Ilr L Y WO 94/07619 PCT/AU93/00486 7 the other of the flats 11. The leading edges 17 of the thread sections 13 define cutting edges of the rock bolt 3.
The rock bolt 3 is formed by welding together two identical elongate members identified by the numerals 21a, 21b in Figures 2 to 4 along the longitudinal edges 41 of the members 21a, 21b. The welds are identified by the numerals 43 in Figures 2 and 4.
In the preferred embodiment shown in Figures 2 and 3 the longitudinal edges 41 of the members 21a, 21b are formed with tongue and groove profiles 27 in order to maximise the surface area of contact between the longitudinal edges 41 and to enable proper alignment of the members 21a, 21b prior to welding together the members 21a, 21b. In addition, the longitudinal edges 41 of the members 21a, 21b are formed to define outwardly opening V-shapad weld metal channels 43 when the members 21a, 21b are in contact.
In the preferred embodiment shown in Figure 4 the longitudinal edges 41 are formed so that there is a relatively small surface area of contact between the longitudinal edges 41 and relatively large (compared with the preferred embodiments shown in Figures 2 and 3) outwardly opening V-shaped weld channels 43.
The members 21a, 21b are formed by rolling in a normal rolling process at high speed. The rolled members 21a, 21b are fed into a jig and mated together so that the threaded profiles of the members 21a, 21b are matched and form a discontinuous threaded profile. Finally, the members 21a, 21b are welded together using high speed robotic welding equipment.
I
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WO 94/07619 PCT/AU93/00486 8 It is noted that in the case of the preferred embodiment shown in Figures 2 and 3 the tongue and groove profiles 27 ensure proper alignment of the members 21a, 21b and in the case of the preferred embodiment shown in Figure 4 the members 21a, 21b are aligned by the flats 11 and the threaded profiles.
The rock bolt 3 can be manufactured at significantly lower cost than is possible with the known methods and at large scale production.
Many modifications may be made to the preferred embodiment of the rock bolt 3 and the method of manufacturing the rock bolt 3 without departing from the spirit and scope of the present invention.
In this regard, whilst the preferred embodiment comprises welding together the elongate members 21a, 21b, it can readily be appreciated that the present invention is not so limited and extends to any suitable means including the use of adhesives to connect together the members.
Furthermore, whilst the preferred emwbodiment of the rock bolt 3 is formed from two identical elongate members 21a, 21b, it can readily be appreciated that the present invention is not so limited and the rock bolt 3 could be formed from any suitable number of members.
Furthermore, whilst the preferred embodiment of the rock bolt 3 is formed from steel, it can readily be appreciated that the present invention is not so limited and the rock bolt 3 could be formed from any suitable material.
Ls WO 94/07619 PCT/AU93/00486 9 Furthermore, whilst the preferred embodiments relate to the rock bolt 3 and the method of manufacturing the rock bolt 3, it can readily be appreciated that the present invention is not so limited and extends to any hollow element, such as drill rods, pipes and tubes.
Claims (22)
1. A method of manufacturing a rock bolt or a drill rod having an axially extending bore, the method comprising the steps of: rolling or die drawing two or more elongate members each of which forms a segment of the rock bolt or the drill rod and comprises an internal wall and an external wall; and connecting the members together along the longitudinal edges of the members to form the rock bolt or the drill rod with the internal walls of the members defining the axially extending bore.
2. The method defined in claim 1 wherein there are two identical members.
3. The method defined in claim 1 or claim 2, further comprising, rolling or die drawing each member to form on the external wall a section of a threaded profile so that the rock bolt formed by comnecting the members together comprises the threaded profile.
4. The method defined in claim 3, wherein the threaded profile is continuous.
The method defined in claim 1 or claim 2, wherein the step of rolling or die drawing the members e. exyterinoA o-P forms a half hexagonal shape on each of the members so that the drill rod formed by connecting the members together comprises a complete hexagonal profile. -m F WO 94/07619 1 1 PCT/AU93/00486
6. The method defined in any one of the preceding claims, wherein the step of connecting the members together comprises welding or gluing the members together.
7. The method defined in claim 6, wherein the step of connecting the members together comprises, feeding the members into a jig, aligning the members, and welding or gluing the members together.
8. The method defined in any one of claims 3 to 5, wherein the step of rolling or die drawing the members forms the longitudinal edges of the members with profiles to maximise the surface area of contact and enable proper alignment when connecting the members together.
9. The method defined in claim 8, wherein the profiles are tongue and groove profiles.
10. The method defined in any one of the preceding claims, wherein the step of rolling or die drawing the mrctbers forms the longitudinal edges so that when the members are positioned together the adjacent longitudinal edges define the sides of ,n outwardly opening channel for receiving weld metal or glue to connect the members together.
11. The method defined in any one of claims 1 to 4, wherein the rock bolt has a diameter of 15 to 50mm and a maximum wall thickness of at least
12. A rock bolt or a drill rod having an axially extending bore, the rock bolt or the drill rod comprising two or more elongate members formed by rolling or die drawing which are connected together along the longitudinal edges of the members, each member having an internal wall and an external wall, and the internal walls defining the s -d -d 1 II_ I WO 94/07619 1 2 PCT/AU93/00486 axially extending bore.
13. The rock bolt or the drill rod defined in claim 12 consisting of two identical members.
14. The rock bolt or the drill rod defined in claim 12 or claim 13, wherein the longitudinal edges of the members comprise profiles that maximise the surface area of contact between the longitudinal edges of adjacent members and enable proper alignment of the members.
The rock bolt or the drill rod defined in claim 14, wherein the profiles are tongue and groove profiles.
16. The rock bolt or the drill rod defined in any one of claims 12 to 15, wherein the members are connected together by welding or gluing.
17. The rock bolt or the drill rod defined in claim 16, wherein the longitudinal edges of the members define outwardly opening channels which receive weld metal or glue.
18. The rock bolt defined in any one of claims 12 to 17, wherein the external wall of each member comprises a part of a threaded profile.
19. The rock bolt defined in claim 18, wherein the threaded profile is continuous.
The rock bolt defined in claim 18 or claim 19, wherein the rock bolt has a diameter of 15 to 50mm and a maximum wall thicknless of at least I I I _L WO 94/07619 13 PCT/AU93/00486
21. A method of manufacturing a hollow bar substantially as hereinbefore described with reference to the accompanying drawings.
22. A hollow bar substantially as hereinbefore described with reference to the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU48116/93A AU672428B2 (en) | 1992-09-25 | 1993-09-22 | Hollow bars and method of manufacture |
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AUPL494292 | 1992-09-25 | ||
| AUPL4942 | 1992-09-25 | ||
| PCT/AU1993/000486 WO1994007619A1 (en) | 1992-09-25 | 1993-09-22 | Hollow bars and method of manufacture |
| AU48116/93A AU672428B2 (en) | 1992-09-25 | 1993-09-22 | Hollow bars and method of manufacture |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| AU4811693A AU4811693A (en) | 1994-04-26 |
| AU672428B2 true AU672428B2 (en) | 1996-10-03 |
Family
ID=25628141
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU48116/93A Ceased AU672428B2 (en) | 1992-09-25 | 1993-09-22 | Hollow bars and method of manufacture |
Country Status (1)
| Country | Link |
|---|---|
| AU (1) | AU672428B2 (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU341619A1 (en) * | К. Ф. Борисов, Н. Л. Кокорев, О. М. Фартушной , Н. М. Алиев | WELDING TAPE FOR THE MANUFACTURE OF PIPES WITH A LONGITUDENT SEAM | ||
| SU254452A1 (en) * | 1967-07-10 | 1981-09-07 | Aliev N M | Device for producing welded two-seam tubes |
| JPH06154217A (en) * | 1992-11-19 | 1994-06-03 | Shimadzu Corp | Ultrasonic diagnosing apparatus |
-
1993
- 1993-09-22 AU AU48116/93A patent/AU672428B2/en not_active Ceased
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU341619A1 (en) * | К. Ф. Борисов, Н. Л. Кокорев, О. М. Фартушной , Н. М. Алиев | WELDING TAPE FOR THE MANUFACTURE OF PIPES WITH A LONGITUDENT SEAM | ||
| SU254452A1 (en) * | 1967-07-10 | 1981-09-07 | Aliev N M | Device for producing welded two-seam tubes |
| JPH06154217A (en) * | 1992-11-19 | 1994-06-03 | Shimadzu Corp | Ultrasonic diagnosing apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| AU4811693A (en) | 1994-04-26 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PC | Assignment registered |
Owner name: ONESTEEL MANUFACTURING PTY LIMITED Free format text: FORMER OWNER WAS: BHP ENGINEERING PTY. LTD. |
|
| MK14 | Patent ceased section 143(a) (annual fees not paid) or expired |