AU2004240243B2

AU2004240243B2 - Sleeve extraction

Info

Publication number: AU2004240243B2
Application number: AU2004240243A
Authority: AU
Inventors: Andrew Robert Mccormack; Steven Lee Weaver
Original assignee: Sandvik Intellectual Property AB
Current assignee: Sandvik Intellectual Property AB
Priority date: 2004-12-20
Filing date: 2004-12-20
Publication date: 2011-09-01
Anticipated expiration: 2024-12-20
Also published as: AU2004240243A1; ZA200510289B

Abstract

An arrangement for extracting a cylindrical sleeve 14 from within a bore 15 of a 5 cutting head 16 in which the sleeve 14 is frictionally engaged with the inner surface of the bore, the sleeve 14 includes a thread formed on an outer surface 22 of a portion of the sleeve 14 that extends from the bore 15, and the extraction arrangement 50 includes threaded engagement means for threadably engaging the thread of the outer surface 22, the extraction arrangement 50 10 including means to apply an extraction load to the engagement means in a direction to extract the sleeve 14 from the bore 15, the extraction load being sufficient to overcome the frictional engagement between the sleeve 14 and the bore 15 to remove the sleeve 14 from the bore 15.

Description

AUSTRALIA Patents Act COMPLETE SPECIFICATION (ORIGINAL) Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority Related Art: Name of Applicant: Sandvik AB Actual Inventor(s): Michael Andrew McLean, Steven Weaver Address for Service and Correspondence: PHILLIPS ORMONDE & FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street Melbourne 3000 AUSTRALIA Invention Title: SLEEVE EXTRACTION Our Ref: 731373 POF Code: 375057/11209 The following statement is a full description of this invention, including the best method of performing it known to applicant(s): 60- q 2 SLEEVE EXTRACTION The present invention relates to the extraction of wear sleeves from the block of a cutting head or cutting drum (hereinafter "cutting head") which employs pick 5 assemblies for mechanical rock excavation, such as road heading, continuous mining and long wall mining, and for surface mining or road milling. A reference herein to a patent document or other matter which is given as prior art is not to be taken as an admission that that document or matter was known 10 or that the information it contains was part of the common general knowledge as at the priority date of any of the claims. In mining operations, in particular coal mining by continuous miners, cutting heads having a plurality of pick assemblies projecting therefrom are employed, 15 and these pick assemblies are driven into a rock wall to dislodge rock from the wall. The cutting heads include a block which is driven to rotate, and a plurality of the pick assemblies are fixed to the block and project therefrom. Pick assemblies usually comprise a head and a shank and the head is of hardened steel and includes a tungsten carbide tip. The pick assemblies are fixed to the 20 block within a sacrificial wear sleeve so that the sleeve, which is replaceable, will wear rather than the bore of the block. The sleeve usually is a friction fit within a bore formed in the block, while the pick assembly is loosely fitted within the sleeve, so that during cutting the pick assembly can rotate to minimise wear of the pick assembly. However, it is the pick assemblies which cut into the rock 25 wall and over time the pick assemblies wear, requiring replacement. When a pick assembly is required to be replaced the sleeve can also be replaced if it is worn sufficiently. It is the preference to remove both the pick assembly and the sleeve from the cutting head within the mine so as to minimise downtime. However, while removal of the pick assembly is usually straightforward, often 30 sleeve removal is difficult and therefore time consuming. Indeed, sometimes it is not possible for the sleeve to be removed within the mine and so it is then necessary for the entire cutting head to be removed and taken to the surface of 3 the mine. In this latter circumstance, significant downtime can be experienced to the detriment of mine efficiency. One manner of removing a sleeve from the bore of a block, is to insert a plunger 5 and a tube through the interior of the sleeve whereby the tube engages an underneath surface of the sleeve and the plunger bears against an inner end of the bore. An adapter is fixed to the tube and a load is applied both to the plunger and the adapter in opposite directions to lift the tube and therefore also the sleeve, out of the block bore. A disadvantage of this arrangement, is that 10 the bearing area of the plunger against the inner end of the bore is limited, because of the necessity to also include the tube within the sleeve. That is, while it is desirable that the cross-section of the plunger be maximised to maximise the bearing area of the plunger and to therefore maximise the load that can be applied to the plunger without failure, the plunger cannot take the 15 full cross-section of the interior of the sleeve because of the necessity to also insert the tube into the sleeve. Moreover, typically the interior sleeve diameter is about 25 to 30 mm so that properly fixing the tube and the plunger within the sleeve can be an awkward operation in the environment of a mine. 20 It is an object of the present invention to provide an extractor which overcomes or at least alleviates one or more of the foregoing disadvantages. According to the present invention there is provided an arrangement for extracting a cylindrical sleeve from within a bore of a cutting head in which the 25 sleeve is frictionally engaged with the inner surface of the bore, wherein the sleeve includes a thread formed on an outer surface of a portion of the sleeve that extends from the bore, and the extraction arrangement includes threaded engagement means for threadably engaging the thread of the outer surface, the extraction arrangement including means to apply an extraction load to the 30 engagement means in a direction to extract the sleeve from the bore, the extraction load being sufficient to overcome the frictional engagement between the sleeve and the bore to remove the sleeve from the bore.

4 The present invention further provides a method for extracting a cylindrical sleeve from within a bore of a cutting head in which the sleeve is frictionally engaged with the inner surface of the bore, wherein the sleeve includes a thread formed on an outer surface of a portion of the sleeve that extends from 5 the bore, the method including applying threaded engagement means to threadably engage the thread of the outer surface and applying an extraction load to the engagement means in a direction to extract the sleeve from the bore. 10 In a preferred arrangement, the extraction arrangement further includes a member that extends into the interior of the sleeve for engagement with an end surface of the bore. In this arrangement, a second or reaction load is applied to the member in a direction for engagement with the end surface which load is in the opposite direction to the extraction load and the extraction and reaction 15 loads are substantially equal. In the preferred arrangement, the member that extends into the interior of the sleeve is a plunger which can be of any suitable shape, but which is preferably circular in cross-section, and which has a diameter that is slightly less than the 20 internal diameter of the sleeve into which it extends. By this arrangement, maximum pressure can be applied to the end surface of the bore and this differs from prior art arrangements, in which a plunger of significantly reduced diameter compared to the inside diameter of the sleeve must be employed. Accordingly, compared to the prior art, the load that can be applied through the plunger is 25 significantly increased or alternatively, an increased load can more confidently be applied to the plunger with reduced likelihood of plunger failure. The engagement between the outer surface of the portion of the sleeve that extends from the bore and the engagement means is threaded engagement 30 and for this, the sleeve can include a threaded portion formed at or adjacent an end of the sleeve. In the preferred arrangement, the threaded portion is formed on a collar section of the sleeve, the collar section being formed at the end of the sleeve that extends from the bore and extending generally laterally to the 5 axis of the sleeve to overlie in abutting engagement, a facing rim portion of the bore opening. In that arrangement, the collar section defines an outer facing circular periphery on which a thread can be formed for engagement by threaded engagement means. 5 The present invention further provides a pick assembly and sleeve arrangement, the pick assembly including a head, a cylindrical shank and a circular shoulder disposed between the shank and the head, the sleeve having an internal diameter sized for loose receipt of the shank so that the shank can 10 rotate within the sleeve, the sleeve including a thread formed on an outer surface thereof at an end of the sleeve adjacent the pick assembly head for threaded engagement by a sleeve extracting device, the shoulder extending radially beyond the shank to overhang the thread. 15 In a preferred arrangement, the circular shoulder disposed between the shank and the head extends radially beyond the shank sufficient for the shoulder to overhang the thread. By this arrangement, the shoulder can provide protection, such as to protect the thread against wear and to eliminate or reduce the likelihood of the thread becoming choked by dust and debris created during a 20 cutting operation. Instead, the shoulder can deflect dust and debris away from the thread. In another arrangement, a ring can be employed to cover the thread and to protect it during cutting. In the preferred arrangement, a nut can be threaded 25 onto the thread of the sleeve so that the sleeve thread is covered and protected by the nut during cutting. In this arrangement, the nut can be threaded into abutting engagement with an undersurface of a portion of the shoulder that overhangs the thread. However, it is to be appreciated that in this form of the invention, a shoulder is not necessarily required. 30 In still a further arrangement, the pick assembly can include an annular shroud which can extend from the shoulder or other suitable part of the pick assembly, generally axially to overlie the thread, again for the purpose of providing wear 6 protection and to hinder the possibility of the thread becoming blocked or obstructed. In one arrangement the shroud can taper outwardly, so that any dust or debris which comes into engagement with the shroud, is directed away from the thread. 5 The present invention further provided a cylindrical sleeve for fitting into the bore of a cutting head and for accommodating the shank of a pick assembly, the sleeve including an end portion that in use extends from the bore, wherein the sleeve includes a thread formed on an outer surface of the end portion for 10 threaded engagement by an extraction arrangement for extracting the sleeve from the bore. The pick assembly above can additionally include an annular shroud that extends axially from the shoulder in facing relationship with the portion of the 7 sleeve that extends out of the bore for the protective reasons previously discussed. For a better understanding of the invention and to show how it may be 5 performed, embodiments thereof will now be described, by way of non-limiting example only, with reference to the accompanying drawings. Figure 1 is a detailed view of a pick assembly mounted in a cutting head block according to one embodiment of the invention. 10 Figures 2 and 3 show a similar view to Figure 1, but of alternative embodiments of the invention. Figures 4 and 5 illustrate the embodiment of Figure 2 and the method of 15 extraction of the sleeve of that embodiment. Figures 6 and 6a show perspective and side views of a sleeve for use in the invention. 20 Figure 7 shows the sleeve of Figures 6 and 6a with a nut attached to the threaded portion thereof and Figure 7a shows the nut of Figure 7 in cross section. Figure 8 shows an alternative arrangement according to the invention. 25 Figure 1 illustrates a first embodiment of the invention and this figure shows a pick assembly 10 comprising a head 11, a cylindrical shank 12 and a shoulder 13. The shank 12 is inserted within a sleeve 14 which is frictionally engaged within a bore 15 formed in a block 16 of a cutting head (not shown). The sleeve 30 14 comprises an annular body 17 and an annular collar 18 which extends from a section of the body 17 which projects outwardly from the bore 15. The shank 12 is loosely fitted into the sleeve 14 and the shank includes an annular recess 19 for receipt of a circlip (not shown) or the like and it is the circlip that secures W:Julie\Andrew\Speci\Sleeve Extraction.doc 8 the pick assembly 10 within the sleeve 14 against release axially therefrom. However, by securing the shank within the sleeve in this manner, the pick assembly 10 is allowed to rotate within the sleeve 14. An alternative to a circlip is to employ a nut or a pin. 5 The block 16 is attachable to a cutting head in any suitable manner, such as by welding. The cutting head is not shown in Figure 1, although it will be appreciated that the head would include a suitable recess to accept the base 20 of the block 16 for attachment to the head. 10 It is normal for the inside end 21 of the bore 15 to open laterally of the block 16, so that circlip removal, or removal of other forms of fastener as may be employed, such as a nut or a pin, can be achieved by a suitable implement inserted into the inside end 21. 15 The collar 18 has an outer annular surface 22 and a thread is formed over that surface. As will become apparent later, that thread is employed in the removal of the sleeve 14 from frictional engagement with the bore 15. Before discussing the method of removal, it can be seen from Figure 1, that the shoulder 13 20 extends radially beyond the outer annular surface 22 of the collar 18 to overhang that surface. This construction of the shoulder 13 provides protection for the thread against wear and against dust and other debris which is generated during a cutting operation so that the thread is protected against build up of dust and debris which may interfere with the subsequent operation of 25 the thread during sleeve removal. In the preferred construction, the diameter D (Figure 1) of the shoulder 13 is approximately equal to the thread diameter of the thread formed on the surface 22 plus the height H of the collar 18 or twice the height H. Alternatively, the diameter D could be about equal to 1.5 times the thread diameter, or 1.25 times the thread diameter. 30 Figure 2 illustrates a similar arrangement to that shown in Figure 1, with a modification as will be hereinafter described. Because Figure 2 shows many of the same parts as shown in Figure 1, like parts have the same reference W:\Juie\Andrew\Speci\Sleeve Extraction.doc 9 numerals. Where the arrangement of Figure 2 differs from that of Figure 1, is by the addition of a nut 23 in threaded engagement with the outer surface 22 of the collar 18. The nut 23 is shown in abutting engagement with the under surface 24 of the shoulder 13 and against the rim or outer surface 25 of the 5 block 16 which surrounds the opening of the bore 15 although the abutting engagement with either surface 24 or 25 is preferred and not essential. The threaded engagement of the nut 23 with the outer surface 22 provides complete coverage and protection for the thread formed on the outer surface 22 against choking by dust and debris created during a cutting operation. 10 Figure 3 illustrates a further alternative arrangement to that shown in Figures 1 and 2, and again, the majority of the arrangement shown in Figure 3 is the same as that shown in Figures 1 and 2 and therefore like parts again have the same reference numerals. In Figure 3, an annular shroud 26 extends axially 15 from the collar 18 to closely overlie the threaded outer annular surface 22. The shroud is formed as an integral extension of the shoulder 13 and extends for substantially the full axial extension of the outer surface 22. In this arrangement, the shroud 26 provides a protective cover for the thread formed on the surface 22 for the same reasons as discussed in relation to Figures 1 20 and 2. The respective arrangements shown in Figures 1 to 3 are provided for protection of the thread formed on the outer surface 22. The thread forms part of the mechanism by which the sleeve 14 of each of the embodiments shown in 25 Figures 1 to 3 can be removed from frictional engagement within the bore 15 when it is desired to remove the sleeve for replacement. With reference now to Figures 4 and 5, Figure 4 shows the embodiment illustrated in Figure 2, in which a nut 23 is threadably attached to the outer annular surface 22. Because Figure 4 is for illustrative purposes only, the sleeve 14 is not shown in a worn 30 state, but nevertheless, it will be appreciated that sleeve removal typically will only need to take place upon either the pick assembly 10 wearing, or the sleeve 14 wearing to a sufficient extent, that the integrity of a cutting operation is compromised. That being the case, then sleeve removal firstly requires the pick W:Uulie\Andrew\SpeciSleeve Extraction.doc 10 assembly 10 to be removed. This requires removal of the fastening arrangement, which usually is a circlip, located in the recess 19. Circlip removal can be by any suitable arrangement as presently employed. 5 With the pick assembly 10 removed from the sleeve 14, the nut 23 can also be removed and for this, the nut can include flats for spanner engagement, or it can include openings for pin engagement. Digressing briefly, and referring to Figures 6 and 7, a sleeve 30 is shown having a body 31 and a collar 32 and including an axial step 33. The collar 32 includes a thread 36 formed on an 10 outer annular surface of the collar. The axial step 33 is a known characteristic of sleeves of this kind and is employed to minimise the difficulty with sleeve removal from a block bore. In this respect, while each of the sections 34 and 35 of the body 31 engage frictionally with the internal surface of a block bore, because the diameter of the section 35 is less than that of the section 34, when 15 the sleeve has been removed so that the reduced diameter section 35 is in the section of the bore which was previously in frictional engagement with the larger diameter section 34, the section 35 will not be in engagement with the block bore, so that the sleeve will be loose and easily removed. 20 With reference to Figure 7, this shows the sleeve 30 of Figures 6 and 6a but with a nut 37 applied to the thread 36 of the collar 32. Figure 7a is a cross sectional view of the nut 37 showing an internally facing thread 38 while Figure 7 shows the nut 37 threadably attached to the sleeve 30. In the views of Figures 7 and 7a, it can be seen that the nut 37 includes a plurality of axially 25 extending openings 39 for receipt of a suitable pin of a tool employed for applying and removing the nut from threaded engagement with the sleeve 30. The thread 36 can have any suitable form, such as a square, round or Acme thread. A round thread might endure greater wear than other forms of thread 30 and still perform adequately and therefore a round thread is preferred. While not claimed as part of the invention, instead of a thread 36 being applied to the collar 32, alternative arrangements can be employed and for example, a 11 engaged by a tool. Figure 8 shows such an arrangement including part of a suitable tool to engage the annular groove. The arrangement of Figure 8 shows a sleeve 60 which defines a body 61 and a collar 62. The collar 62 includes an annular groove 63. Figure 8 further shows an end portion 64 of an extractor 5 sleeve for engaging the collar 62 for extracting the sleeve 60 from a block bore. The end portion 64 is open laterally and includes a projection 65 for snug receipt within the groove 63. Clearly the reverse arrangement could be provided, whereby the groove 63 could be provided in the end portion 64 and the projection 65 could project from the collar 62. The projection 65 can be 10 extended as shown in broken outline, to increase the extent of engagement between the projection 65 and the groove 63. In the arrangement of Figure 8, the end portion 64 of an extractor sleeve is shown ready to be engaged with the collar for extraction in a manner as 15 hereinafter described with particular reference to Figures 4 and 5. However, before proceeding to that description, it will be appreciated that while two arrangements for collar engagement have been described above (threaded engagement and projection and groove engagement), it is envisaged that other 20 different arrangements could be employed for the same purpose. Returning to Figures 4 and 5, upon removal of the pick assembly 10, the nut 23 is removed such as in the manner discussed above, and an extractor sleeve 50 is threadably attached to the thread formed on the outer annular surface 22. 25 Also, in the space left by removal of the shank 12 from within the sleeve 14, a plunger 51 of substantially the same diameter as the interior of the sleeve 14, is inserted into the sleeve 14. In the direction of the arrows shown, opposite forces are applied to the extractor sleeve 50 and to the plunger 51 whereby the plunger 51 engages against under load, the inside end surface 40 of the inside 30 end 21 and the extractor sleeve 50 imposes an opposite force through the collar 18 of the sleeve 14. By this arrangement and with suitable forces exerted, the sleeve 14 can be removed from frictional engagement with the bore 15 in a simple and effective manner. Advantageously, only a single element, the W:\Juie\Andrew\Speci\Sleeve Extraction.doc 12 plunger 51, is required to be inserted into the sleeve 14 for.engagement with the inside end surface 40 of the bore 15, while the extractor sleeve 50 is easily applied by threaded engagement with the thread formed on the outer surface 22. With this connection, a suitable hydraulic or pneumatic jacking device can 5 be employed to apply the required forces. The arrangement of Figures 4 and 5 can apply to each of the arrangements shown in Figures 1 to 3, as the difference in those figures relates to the construction of the pick assembly 10 rather than any change in the manner of 10 sleeve removal. Accordingly, the method of sleeve removal shown in Figures 4 and 5 could apply to any one of the pick assembly arrangements shown in Figures 1 to 3. In relation to Figure 8, the end portion 64 is shifted generally laterally into 15 engagement with the collar 62 relative to the axis of the sleeve 60. The invention described herein is susceptible to variations, modifications and/or additions other than those specifically described and it is to be understood that the invention includes all such variations, modifications and/or additions which 20 fall within the spirit and scope of the above description. W:\Julie\Andrew\Speci\Sleeve Extraction.doc

Claims

1. An arrangement for extracting a cylindrical sleeve from within a bore of a cutting head in which the sleeve is frictionally engaged with the inner surface of 5 the bore, wherein the sleeve includes a thread formed on an outer surface of a portion of the sleeve that extends from the bore, and the extraction arrangement includes threaded engagement means for threadably engaging the thread of the outer surface, the extraction arrangement including means to apply an extraction load to the engagement means in a direction to extract the sleeve 10 from the bore, the extraction load being sufficient to overcome the frictional engagement between the sleeve and the bore to remove the sleeve from the bore.

2. The arrangement according to claim 1, wherein the portion of the sleeve 15 that extends out of the bore is a collar that overlies in abutting engagement with a rim portion of the bore and which defines a circular periphery, the thread being formed on the circular periphery and the engagement means engaging the thread on the circular periphery of the collar. 20

3. The arrangement according to claim 1 or 2, the sleeve having an interior and the extraction arrangement further including a member that extends into the interior of the sleeve for engagement with an end surface of the bore, whereby during extraction of the sleeve from the bore, a reaction load is applied to the member in a direction for engagement with the end surface, the extraction and 25 reaction loads being substantially equal.

4. The arrangement according to claim 3, wherein the sleeve has an internal diameter and the member is a plunger which has a diameter slightly less than the internal diameter of the sleeve. 30

5. A method for extracting a cylindrical sleeve from within a bore of a cutting head in which the sleeve is frictionally engaged with the inner surface of the bore, wherein the sleeve includes a thread formed on an outer surface of a 14 portion of the sleeve that extends from the bore the method including applying threaded engagement means to threadably engage the thread of the outer surface and applying an extraction load to the engagement means in a direction to extract the sleeve from the bore. 5

6. The method according to claim 5, the sleeve having an interior and the method further including inserting a member into the interior of the sleeve for engagement with an end surface of the bore and applying a reaction load to the member in a direction for engagement with the end surface, the extraction load 10 being sufficient to overcome the frictional engagement between the sleeve and the bore, and the reaction load being substantially equal to the extraction load.

7. A pick assembly and sleeve arrangement, the pick assembly including a head, a cylindrical shank and a circular shoulder disposed between the shank 15 and the head, the sleeve having an internal diameter sized for loose receipt of the shank so that the shank can rotate within the sleeve, the sleeve including a thread formed on an outer surface thereof at an end of the sleeve adjacent the pick assembly head for threaded engagement by a sleeve extracting device, the shoulder extending radially beyond the shank to overhang the thread. 20

8. The arrangement of claim 7, wherein the thread is formed on a radially extending, circular collar.

9. The arrangement of claim 7 or 8, including a ring disposed about the 25 thread to cover the thread during cutting.

10. The arrangement of claim 9, wherein the ring is a nut threadably connected to the thread of the sleeve to cover the thread during cutting. 30

11. The arrangement of claim 10, the nut being in abutting engagement with an under surface of the portion of the shoulder that overhangs the thread. 15

12. The arrangement of any one of claims 7 or 8, the pick assembly including an annular shroud suitable to overlie the thread.

13. The sleeve as defined in any one of claims 7 to 12. 5

14. A cylindrical sleeve for fitting into the bore of a cutting head and for accommodating the shank of a pick assembly, the sleeve including an end portion that in use extends from the bore, wherein the sleeve includes a thread formed on an outer surface of the end portion for threaded engagement by an 10 extraction arrangement for extracting the sleeve from the bore.

15. The sleeve according to claim 14, the end portion being formed as a collar having a greater diameter than the bore into which the sleeve is fitted, and the thread being formed on the outer surface of said collar. 15

16. An arrangement for extracting a cylindrical sleeve from within a bore of a cutting head in which the sleeve is frictionally engaged with the inner surface of the bore, substantially as hereinbefore described with reference to the accompanying drawings. 20

17. A method for extracting a cylindrical sleeve from within a bore of a cutting head in which the sleeve is frictionally engaged with the inner surface of the bore, substantially as hereinbefore described with reference to the accompanying drawings.