AU2005200219A1

AU2005200219A1 - Grinding apparatus

Info

Publication number: AU2005200219A1
Application number: AU2005200219A
Authority: AU
Original assignee: Sandvik Intellectual Property AB
Current assignee: Sandvik Intellectual Property AB
Priority date: 2005-01-18
Filing date: 2005-01-18
Publication date: 2006-08-03

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): Address for Service and Correspondence: PHILLIPS ORMONDE FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street Melbourne 3000 AUSTRALIA Invention Title: GRINDING APPARATUS Our Ref: 736935 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): -1- GRINDING APPARATUS Field of the Invention 00oo The present invention relates to grinding apparatus and profiling pick assemblies employed for such apparatus, principally for grinding concrete (1 surfaces such as floors. It will be convenient to describe the present invention as it applies to concrete grinding, but it should be appreciated that the invention is not limited to concrete grinding and could, for example, also have application for grinding surfaces which are other than concrete, such as ceramic paving, stone and asphalt.

Background of the Invention Concrete grinding is employed to level concrete surfaces, such as to remove high spots in the surface of the concrete and to prepare a concrete surface for polishing, or other treatment such as painting. The actual grinding can vary from highly aggressive, to light or fine, depending on the grinding requirements and the grinding apparatus which is employed is to some extent dictated by the type of grinding which is undertaken. The present invention relates to relatively aggressive grinding.

Summary of the Invention In a first aspect of the present invention there is provided a profiling pick assembly which comprises: a cylindrical shaft for receipt within a bore of a grinding head; a body extending from one end of the shaft; a grinding tip having a base end which is fixed to the body and which protrudes therefrom, the protruding portion including a cylindrical section which extends from the base end and a tapered section which extends from the cylindrical section and converges towards a distal tip; W:Uu1ie1AndrevSpecGrdnding Apparatus.doc

I

wherein the relationship between the diameter of the cylindrical section and the axial height of the cylindrical section is: 0.25D H 0_ where H the axial height of the cylindrical section; and D the diameter of the cylindrical section.

c A profiling pick assembly according to the invention (hereinafter a "pick assembly") preferably includes a grinding tip in which the relationship between the diameter of the cylindrical section and the axial height of that section is: 1D 1H52D In a particularly preferred arrangement, the relationship is as follows: H It is preferred that the tapered section has a general angle of taper (the "tip angle") which is measured between the outer tapered surface of the tapered section and a line offset from, but extending parallel to the axis of the cylindrical section, of between 30' to 800, more preferably between 400 to 70 most preferably either about 450 or 500. It is further preferred that the tapered section is a conical section. The tapered section can be tapered linearly or curved, and if the taper is curved, the angle of taper is measured from a line passing through the general taper of the section and the offset line described above.

In a first embodiment, the body defines an end surface which is generally planar and which extends generally perpendicular to the axis of the cylindrical section of the grinding tip. In this embodiment, the base end of the grinding tip sits against the end surface of the body for abutting engagement with the end surface. A stud weld or braze can be employed to fix the base end to the end surface. The base end can be an end surface of the cylindrical section so that the cylindrical section extends to abut the body. Alternatively the base surface can extend from the body to the cylindrical section. For example, the base end can be a tapered end section, or square or rectangular, or any other suitable shape. The base end can be configured for welding or brazing to the body and W:AJulie\AndrewXSpec\Grinding Apparatus.doc can include location means to properly locate the grinding tip relative to the body.

00 In a second alternative embodiment, the base end of the grinding tip can be received with a recess formed in the body and a protruding portion of the grinding tip protrudes from the recess. In this embodiment, the protruding N portion includes the cylindrical section and the tapered section discussed Sabove. The use of a recess to receive the base end provides for more secure attachment of the grinding tip to the body, but increases the length of the grinding tip which increases its cost. Accordingly, the abutting engagement of the first embodiment is preferred provided the required strength of the attachment can be achieved.

The protruding portion may include a portion of the base end that extends out of the recess and which extends to the cylindrical section. That portion of the base end can have the same shape as the portion of the base end that is captured within the recess, or it can be otherwise shaped, such as tapered.

The shank and body typically will be made of steel and typically they will be integrally formed. The grinding tip can be a tungsten carbide tip, a diamond grinding tip, a silicon diamond tip, or it can be of any other suitable material which has a sufficient hardness for the grinding purpose to which the pick assembly is to be applied.

The pick assemblies of the invention preferably are mounted in a grinding head, or a grinding machine including a grinding head, in a manner which facilitates the shanks of the pick assemblies, and thus the pick assemblies themselves, to rotate relative to the bore of the grinding head or grinding machine into which the shank is received, during a grinding operation.

By allowing rotation of the pick assemblies, the face of the grinding tip that engages the surface being ground continually changes, so that the grinding tip wears substantially evenly. This provides for consistent grinding performance W:Uulie\AndrevSped\Grnding Apparatus.doc throughout the life of the pick assembly and maximises the life of the pick assembly when compared to other arrangements in which the grinding component is fixed.

00oo The pick assembly can be mounted for rotation within a grinding head, by including with the pick assembly securing means which in one preferred form Sincludes a split sleeve which is secured to the shank of the pick assembly, 0 loosely about the shank so that the shank can rotate relative to the sleeve. The split in the sleeve is a lengthwise split parallel to the lengthwise axis of the shank and permits the sleeve to be collapsed radially for insertion into the bore of a grinding head or machine and thereafter to resiliently expand within the bore so as to frictionally engage the bore surface. Because the sleeve and shank are secured together, frictional engagement of the sleeve within the bore consequently secures the shank in the bore and thus secures the pick assembly in place.

The shape of the body can have any suitable form or cross section but in the preferred arrangement, the body includes a tapered portion between one end thereof which is adjacent the shank and the opposite end which is adjacent the grinding tip. In this arrangement, the taper converges toward the end which is adjacent the grinding tip. The tapered portion can be provided to ensure that the body is prevented from engaging the surface being ground until such time as the grinding tip has worn significantly. The angle of the taper can be directly relative to the angle of attack of the grinding tip to the surface being ground.

That is, the more acute the angle of attack, usually the greater the body taper will be.

The body can additionally include a cylindrical portion which extends from the end thereof which is adjacent the shank and in this arrangement, the tapered portion extends from the cylindrical portion towards the grinding tip.

W:UulieWxndrew.SpeclGdriding Apparatus.doc The taper of the body can be curved or substantially linear. If the taper is curved, then it preferably is concavely curved. Preferably the general angle of the taper is between about 400 and 700 from horizontal.

o00 The body can further include a radial flange that projects radially outwardly from the body and which is positioned at the end of the body which is Sadjacent the shank. In the embodiment in which the body includes a cylindrical Sportion, it is preferable that the radial flange projects from the body at a portion adjacent the shank and that the cylindrical portion extends from the flange.

A pick assembly according to the invention can be employed in a grinding head or in grinding machinery. The pick assemblies will be mounted for rotation about the lengthwise axis of the shank so that the assemblies can rotate during a grinding operation as the assemblies engage the surface being ground. This causes even wear of the grinding tip to maximise the life of the pick assembly. Preferably the pick assemblies are mounted so that the lengthwise axis of each pick assembly has an angle of attack to the surface being ground of about 300 to 900 More preferably, the angle of attack is about 400 to 500, and most preferably it is 450.

The present invention also provides a method of grinding a hard surface, the method including a grinding machine having a head to which a plurality of pick assemblies as described above have been fixed, the method including rotating the grinding head with the pick assemblies in contact with the hard surface.

The hard surface which is to be ground can be concrete, ceramic paving, stone or asphalt.

For a better understanding of the invention and to show how it may be performed, embodiments thereof will now be described, by way of non-limiting example only, with reference to the accompanying drawings.

W:UulieAndrewSpeGdnding Apparatus.doc r Brief Description of the Drawings Figure 1 is a side view of a pick assembly according to one embodiment oo of the invention.

Figure 2 is a detailed view of the grinding tip and body of Figure 1.

SFigure 3 is a detailed view of a grinding tip and an alternative body according to the invention.

0 Figure 4 is a side view of a grinding head according to the invention.

Detailed Description Figure 1 illustrates a profiling pick assembly 10 which has a shank 11, a body 12 and a grinding tip 13. The shank 11 is cylindrical, and disposed loosely about the shank is a split sleeve 14. The split sleeve 14 is secured loosely about the shank 11 so that the shank 11 can rotate within the sleeve 14 and the sleeve 14 is secured to the shank 11 by receipt of a radially inwardly extending protrusion 15 which is received within an annular groove 16 formed in the shank 11.

As shown, the sleeve 14 includes a lengthwise split 17 and by the provision of this split 17, the sleeve 14 can be collapsed radially inwardly, to insert the sleeve 17 and the shank 11 within the bore of a grinding head, and thereafter the sleeve can be allowed to resiliently expand so as to frictionally engage the surface of the bore. With the sleeve 14 engaged in this manner within a bore, the shank 11 is rotatably within the sleeve so that the pick assembly 10 is likewise rotatable. This is advantageous for grinding, because it enables the grinding tip 13 to wear evenly, in contrast to the wear that would occur if the pick assembly 10 was fixed against rotation. Accordingly, by fixing the pick assembly in a manner which allows it to rotate during grinding, wear of W:UuIe\endrwSpecKtndmnQ Apparwtus.doc the grinding tip 13 is more even and accordingly, the life of the pick assembly can be maximised.

o00 The body 12 includes a flange 18 which extends radially beyond other parts of the body 12, a cylindrical section 19 which extends from the flange 18 and a frustoconical or tapered section 20 which extends from the cylindrical c section 19. The taper of the frustoconical section 20 can be straight, as shown 0 in solid outline, or it can be concavely tapered as shown in broken outline.

The grinding tip 13 protrudes from the apex of the frustoconical section and the grinding tip 13 comprises a cylindrical section 21 and a conical section 22. The taper of the tapered section 20 preferably is at about the same angle as the taper of the conical section The grinding tip 13 is fixed to the body 12 either along the base end 23, which is in abutting engagement with a facing surface of the body 12 or by receipt of the base end 23' in a recess 24 (shown in broken outline) formed in the frustoconical section 20 of the body 12. The depth of receipt of the base end 23 is not shown to scale and it may be that the required depth is substantially less than shown. In one embodiment, a grinding tip in which the diameter of the cylindrical section 21 is about 11mm is embedded within a recess in the body an amount of 12 mm.

Figure 1 further shows an annular washer 25. The washer 23 is separate from the shank 11 and the body 12 and can be frictionally fitted about the sleeve 14. The washer 23 can provide some shock absorbing characteristics between the pick assembly 10 and the grinding head or machinery to which the pick assembly 10 is fitted.

Important to the invention, is the ratio of the diameter of the cylindrical section 21 of the grinding tip 13 relative to the extent to which the cylindrical section extends from the body 12. Referring to Figure 2 as discussed earlier, the ratio is as follows: W:UulieArdrewXSpecdAGrindin g Apparatus.doc 0.25D H: nThe preferred ratios have been discussed earlier herein.

00 oo Figure 3 shows a slight variation to the pick assembly 10 and like parts C* have the same reference numeral, plus 100. Accordingly, the body 112 which c is only shown partially, includes a frustoconical section 120 and a cylindrical Ssection 121. A grinding tip 113 is fixed to the body 112 by a base end 123 thereof being received within a recess formed at the apex of the frustoconical section 120. The grinding tip 113 has the form shown in Figures 1 and 2 such that it includes a cylindrical section 121 and a conical section 122. The body section 112 differs from the shown in Figures 1 and 2, by inclusion of a shoulder 127 which extends radially from the cylindrical section 121 of the grinding tip 113. A section of braze 128 is shown extending between the shoulder 127 and the outer surface of the cylindrical section 121.

Figure 3 also illustrates the "tip angle" Tt of the conical section 122, which is measured between the tapered outer surface of the conical section 122 and a line L which is offset from, but extending parallel to the axis A of the cylindrical section 121. As preferred, the tip angle T{ is about equal to the taper angle Tb of the conical section 120 of the body 112.

Figure 4 is a side view of a grinding head 200 to which a plurality of profiling pick assemblies 201 have been secured. To secure the pick assemblies 201 as shown, the grinding head 200 includes a base 202 to which is fixed a plurality of pick assembly mounting knuckles 203. The mounting knuckles 203 can be secured to the base 202 in any suitable manner. In one arrangement, the mounting knuckles 203 can be cast with the base 202, but in the preferred arrangement, the mounting knuckles 203 are welded to the base 202. This latter arrangement is illustrated in Figure 4. Each mounting knuckle 203 includes a bore and in the arrangement shown, the bore is disposed at an angle to the base 202 of 45' By this arrangement, the shank 204 of a pick assembly 201 is mounted within the bore 205 (shown in broken outline), of the W:UulieAndrewSpecG1nding Apparatus.doc 0mounting knuckles 203, also at 450. As shown in Figure 4, the pick assemblies 201 includes a sleeve 206 disposed about the shank 204 and it is the sleeve 206 which is in frictional engagement with the bore 205, while the shank 204 is 0 o freely rotatable within the sleeve 206.

C It will be appreciated that the 450 angle of attack shown in Figure 4 can N be varied as required between 0° and 900.

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 fall within the spirit and scope of the above description.

W:UuiexAndrewMSpedAGnnding Apparatus.doc

Claims

1. A profiling pick assembly which comprises: 00 a cylindrical shaft for receipt within a bore of a grinding head; a body extending from one end of the shaft; a grinding tip having a base end which is fixed to the body and which Sprotrudes therefrom, the grinding tip including a cylindrical section which 0extends from the base end and a tapered section which extends from the cylindrical section and converges towards a distal tip; wherein the relationship between the diameter of the cylindrical section and the axial height of the cylindrical section is: 0.25D H where H the axial height of the cylindrical section; and D the diameter of the cylindrical section.

2. A pick assembly according to claim 1, wherein the relationship is: 1D H< 2D

3. A pick assembly according to claim 1, wherein the relationship is: H

4. A pick assembly according to any one of claims 1 to 3, wherein the tapered section has a taper of between 30' to 800.

5. A pick assembly according to claim 4, wherein the tapered section has a taper of between 400 to 500.

6. A pick assembly according to claim 4, wherein the tapered section has a taper of about 450 or about 500

7. A pick assembly according to any one of claims 1 to 6 wherein securing means are applied to the shank for securing the shank within the bore of a W:UuU e\AndreSpe dGrnding Apparatus.doc I grinding head in a manner that permits rotation of the shank about the axis of the shank within the bore. 00 8. A pick assembly according to claim 7 wherein said securing means includes a split sleeve which is secured to and loosely disposed about the shank so that the shank can rotate relative to the sleeve and wherein the split in Sthe sleeve permits the sleeve to be collapsed radially for insertion into a bore Sand the sleeve is resiliently expandable to expand within the bore and to frictionally engage the bore surface. 0

9. A pick assembly according to any one of claims 1 to 8, wherein the body includes a tapered portion between one end thereof adjacent the shank and the opposite end thereof adjacent the grinding tip, the taper being convergent toward the end adjacent the grinding tip. A pick assembly according to claim 9, wherein the body includes a cylindrical portion extending from an end thereof adjacent the shank and the tapered portion extends from the cylindrical portion toward the grinding tip.

11. A pick assembly according to claim 9 or 10, wherein the taper is a concave curved taper.

12. A pick assembly according to claim 9 or 10, wherein the taper of the tapered portion is substantially linear.

13. A pick assembly according to claim 10, wherein the taper of the tapered portion is between 40 and 70 from horizontal.

14. A pick assembly according to anyone of claims 10 to 13, wherein the angle of taper of the tapered portion is about equal to the angle of taper of the tapered section of the grinding tip. W:Uulie ndrewSpecGrnding Apparatus.doc A pick assembly according to any one of claims 9 to 14, wherein the body includes a radial flange projecting therefrom and positioned at one end of the body which is adjacent the shank. 00oO

16. A pick assembly according to any one of claims 1 to 15, wherein the body defines an end surface which is generally planar and which extends N generally perpendicular to the axis of the cylindrical section of the grinding tip, Sthe base end of the grinding tip being in abutting engagement with the end surface and being fixed thereto.

17. A pick assembly according to claim 16, wherein the base end of the grinding tip is fixed to the end surface of the body by a stud weld or braze.

18. A pick assembly according to any one of claims 1 to 15, wherein the base end of the grinding tip is received within a recess formed in the body and a protruding portion of the grinding tip protrudes from the recess, the protruding portion including the cylindrical section and the tapered section.

19. A pick assembly according to any one of claims 1 to 18, wherein said grinding tip is a tungsten carbide grinding tip, or a diamond grinding tip, or a silicon diamond grinding tip. A profiling head including a plurality of pick assemblies according to any one of the claims 1 to 19, said profiling head including a bore for receipt of the shank of each pick assembly, the shank being mounted within a bore for rotation about the lengthwise axis of the shank relative to the bore.

21. A profiling head according to claim 20, said pick assemblies being mounted so that the lengthwise axis of each pick assembly has an angle of attack to the surface being ground of about 300 to 900.

22. A profiling head according to claim 21 wherein the angle of attack of each pick assembly is about 400 to 500 W:UulieIAndrewSpecGdnding Apparatus.doc 0 23. A profiling head according to claim 21 wherein the angle of attack of each pick assembly is about 0_ 24. A profiling machine including a profiling head according to any one of claims 20 to 23. A method of grinding a hard surface, the method including a profiling Smachine having a head to which a plurality of pick assemblies according to any one of claims 1 to 19 have been fixed, the method including rotating the profiling head with the pick assemblies in contact with the hard surface.

26. A method of grinding a hard surface, the method including a profiling machine according to claim 24, the method including rotating the profiling head with the pick assemblies in contact with the hard surface.

27. A method according to claim 25 or 26, wherein the hard surface is a concrete surface. DATED: 18 January, 2005 PHILLIPS ORMONDE FITZPATRICK Attorneys for: SANDVIK AB W:Uu11e\ArdreSped\G1nding Apparatus.doc