AU3896901A - Apparatus for sealing a milling liner to a milling shell with improved sealing capacity - Google Patents

Description

AUSTRALIA

Patents Act COMPLETE SPECIFICATION

(ORIGINAL)

Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority Related Art: Name of Applicant: Ronald C Clarke Actual Inventor(s): Ronald C Clarke Address for Service: lP Australia Documents received on.

0 2 7 APR 2001 Batch No: PHILLIPS ORMONDE FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street Melbourne 3000 AUSTRALIA Invention Title: APPARATUS FOR SEALING A MILLING LINER TO A MILLING SHELL WITH IMPROVED SEALING CAPACITY Our Ref: 642105 POF Code: 87876/356776 The following statement is a full description of this invention, including the best method of performing it known to applicant(s): -1- APPARATUS FOR SEALING A MILLING LINER TO A MILLING SHELL WITH IMPROVED SEALING CAPACITY This is a divisional application divided out of application no. 41538/97 the entire contents of which are incorporated herein by reference.

Field This specification describes more than one invention relating generally to spreading the clamping load of a bolt which holds an inner liner to an outer shell used in ore milling operations, sealing the shell so that the wet ore slurry in the inner lining does not leak out of the shell through the mounting holes, and repairing enlarged mounting holes which go through the liner and shell to reestablish the ability of the bolt to maintain its designed and desired preload.

The main invention with which this divisional application is concerned, O however, relates to a repair washer and a repair system for sealing a hole.

15 Discussion of Background and Prior Art Prior Mill Liner Bolting Techniques and Problems Because of individual geometry, the head shape of a conventional tapered or spherical head, counter sunk mill liner bolt, presents a poor load bearing contact with the liner and its mating surface. This condition is due primarily to clearance and manufacturing tolerances between the liner, which is cast, and the radiused, tapered, load bearing area of the bolt, which is forged.

This poor load area contact always causes early embedment with subsequent loss of bolt clamp load soon after assembly. It requires repeated, expensive mill shut downs, for bolt tightening, before an adequate surface contact can be formed to support the required bolt clamp load. In a majority of instances, bolts never establish enough surface area contact to stay tight and have to be X:pwg pat\41538-97aa.doc

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periodically tightened through the life of the liners. Often, loose bolts fatigue and break with expensive consequences if the liners fall out.

Moreover, running with loose bolts is also the cause of bolt holes in the mill shell becoming enlarged, which encourages further loosening and leaking problems eventually leading to expensive repair. Typically, the bolt holes in the liners are case approximately 1/8" larger, all round the bolt head, for a standard 1 2" liner bolt. Fig. 3 shows how inadequately the bolt load surface mates with the liner in a horizontal (radial) plane. Figs. 1, 2 show loss of vertical (axial) contact face with small neck angle differences.

Accordingly, it would be desirable to address the provision of improved •0 bolt tightening features which provide improved mating surfaces and pre-load holding ability, and which prevent loosening and enlargement of the holes through which the bolts pass.

S" 15 Prior Liner Bolt Sealing Problem Prior sealing systems used with liner bolts are designed to give good sealing characteristics, but in doing so, sacrifice jointing efficiency. Typically rubber is introduced between the joint surfaces so that a hard join, metal-to- 0 metal, is never attained. This condition then becomes a gasketed joint and will never hold bolt preloads adequately.

Accordingly, it would also be desirable to address the provision of an improved sealing system without sacrificing joint efficiency by providing metalto-metal contact with simultaneous adequate sealing, in consideration of the problems of the prior art.

X:~wg pat41538-97aa.doc Summary of the Invention According to one aspect, the present invention provides a repair washer for enlarged holes having a shaped body having a top major surface and a bottom major surface and a central bore therethrough, an indentation in the bottom major surface constructed and configured to receive a seal, and a plurality of teeth integral with the bottom major surface inboard of the indentation constructed and configured for gripping a surface which is to be sealed.

In a preferred form of the invention, the indentation in the bottom major surface is an annular groove and the seal is preferably an o-ring seal. The annular groove in the bottom major surface is preferably located near the periphery of the bottom major surface and is constructed and configured to cooperate with the bolt through the central bore and through the fastener overlying the top major surface to simultaneously seal the central bore at the bottom surface.

In a preferred form of the invention, an indentation (again, preferably an annular groove) is located in the top major surface near the central bore and is constructed and configured to cooperate with a bolt through the central bore and through an overlying fastener to seal the central bore at the top surface.

Other preferred features of this aspect of the invention include that the teeth may be serrated and may be constructed and configured to prevent movement and subsequent loosening of the washer while the top and bottom seals are effected when the washer is tightly secured to the sealed surface by an overlying fastener. The bottom major surface portion may be either flat or curved to cooperate with the curved surface which is to be sealed, and the X:wg. pat\41538-97aa.doc 3 bottom major surface may be a load surface, with the annular groove therein constructed and configured to effect a bottom seal on the periphery of the load surface.

In at least one embodiment, therefore, the present invention provides a repair washer for sealing a hole having: a body having a top major surface and a bottom major surface and a central bore therethrough, the top major surface constructed and configured to cooperate with an overlying fastener having a first sealing member for sealing the central bore at 10 the top major surface, l° an indentation in the bottom major surface constructed and configured to receive a second sealing member for sealing the central bore at the bottom major surface, and Oe l a plurality of teeth inboard of the annular groove and integral with the bottom major surface constructed and configured for gripping a surface surrounding the hole which is to be sealed.

According to another aspect, the present invention provides a repair system for sealing a hole in a surface including: a fastener bolt disposed in the hole from one direction and having an end extending outboard of the surface, a body having an outboard major surface, an inboard major surface, and a central bore receiving the end of the bolt therethrough, X:pwg pat4A1538-97aa.doc a first sealing member, a metal washer and a fastener nut secured to the end of the bolt in that order from the other direction sealing the central bore at the outboard major surface of the body, an indentation in the inboard major surface of the body receiving a second sealing member sealing the central bore at the inboard major surface of the body, and a plurality of teeth integral with the inboard major surface of the body between the indentation and the central bore of the body gripping the surface surround the hole.

The above and further features of the repair washer and repair system of :.:the present invention will be more fully appreciated from the following detailed .description of preferred embodiments thereof with reference to the accompanying drawings.

Brief Description of the Drawings Fig. 1 is a front vertical elevation view in partial section of a prior art mill liner.

*o* X:'pwg patA 1538-97aa.doc 1 bolt through a liner and shell to hold the assembly together. This drawing shows radial 2 contact with existing geometry.

3 Fig. 2 is a view similar to Fig. 1 showing different angles between the 4 countersunk hole in the liner and the chamfered edge of the bolt head of the prior art.

This drawing shows axial contact with mismatch of neck angles.

6 Fig. 3 is a top view in partial section taken along the lines 3-3 of Figs. 1,2 7 showing the point of contact between the oval shaped countersunk liner hole and 8 chamfered oval shaped bolt head.

9 Fig. 4 is a view similar to Fig. 1 showing the forged spreader with ridges of the 0 present invention which make good and complete contact with the countersunk hole of the liner when the bolt is preloaded to its desired amount. This drawing shows spreader i2 correcting action both radial and axial.

3 Fig. 5 is a view similar to Fig. 2 again showing the forged ridged spreader of the 14 present invention.

Fig. 6 is a top view in partial section taken along the lines 6-6 of Figs. 16 Fig. 7 is a elevational schematic view of the assembly of Fig. 4 and is identified S.17 as Liner 1.5 Shape/A.

18 Fig. 8 is a plan schematic view of Fig. 7.

19 Fig. 9 is an oblique perspective of the mill bolt with forged ridged spreader of the present invention seen in Figs. 4-8. This drawing shows a load spreader liner 20 having 21 spreader areas 31 and a liner bolt hole 12.

22 Figs. 10, 12, 14, 17, 20, and 22 are perspective views similar to Fig. 9 showing 1 the alternative round, elliptical, square, oblong, spherical, and rectangular neck and 2 head shapes of the present invention. Figs. 11, 13, 15, 18, 21, and 23 are sectional 3 views along the lines 11-11, 13-13, 15-15, 18-18, 21-21, and 23-23 of Figs. 10, 12, 14, 4 17 and 19, 20 and 22, respectively. Fig. 16 is a top plan view of Fig. 14. Fig. 19 is an alternate embodiment of the present invention showing convex teeth similar to the 6 concave teeth of Fig. 7 Fig. 24 is an oblique perspective view of an alternate embodiment of the present 8 invention in the form of forged spreader inserts having deformable ridges according to 9 the present invention. This drawing shows a standard liner bolt 20 in a liner bolt hole 2 with load spreader inserts 40 having spreader areas 41.

.a1 Fig. 25 is a form of the forged spreader of Fig. 10 during an early step in the F 712 manufacturing process of the present invention prior to being forged in its curved final form and is identified as Liner 1.5 Shape/A.

Fig. 26 is a top plan view of the forged insert of Fig. 5 Fig. 27 is a top plan view of Fig. 26 following the forming step which forms the 16 forged spreader into its final curved form.

"17 Fig. 28 is an oblique perspective view of the underside of the special repair 18 washer of the present invention. This drawing shows a special repair washer for 19 enlarged mill liner holes. Fig. 28 shows a serrated load area 53 to prevent movement and subsequent loosening and a special o-ring sealing groove 51 to seal on outside 21 of load area.

22 Fig. 29 is an oblique perspective top view of the special repair washer of the 1 present invention. This drawing shows a liner bolt, nut 23, washer 50, and additional 2 s"o"-ring 54 (in phantom).

3 Fig. 30 is a perspective view of a special repair plate of 4 the present invention also showing an additional embodiment of the improved repair washer of the present invention. This drawing shows a special repair washer 6 (rectangular) having a concave bottom face to match shell 1 curvature, holes for socket 7 screws to clamp plate to shell, and, in a top view, a Valley Forge T M two piece sealing 8 system around liner bolt 20 and under nut 23.

9 Fig. 31 is an oblique partial perspective view of the underside of the repair plate of Fig. 30. This drawing shows a back view of the "o"-ring special sealing groove to seal 1 plate to shell.

S1i2 Fig. 32 is a plan view of the repair plate and repair washer assembly of the 3 present invention and is identified as a repair washer new S/A. This drawing also 14 shows 2 dowell pin holes (unnumbered).

Fig. 33 is a front elevation view in partial section of the repair plate of Fig. 32.

16 The bottom face of this plate will be concave.

17 Fig. 34 is a front elevation view of a drill stopper bushing used in making the 18 present invention.

19 Fig. 35 is a top plan view of Fig. 34.

Fig. 36 is a top plan view of a center drill bushing used in making the present 21 invention.

22 Fig. 37 is a front elevation view in partial section of the center drill bushing of Fig. 36.

Fig. 38 is a top plan view of a tap drill bushing used in making the present invention.

Fig. 39 is a front elevation view in partial section of the tap drill bushing of Fig. 38.

Fig. 40 is a top view in partial section of a drilling process step which is used in making the present invention. This drawing shows a tap bushing in one hole of plate 61.

Fig. 41 is a front elevational view of a drilling process step used in making the present invention. This drawing shows the repair assembly having a certain drill 71 in a drill stopper 74 on a tap bushing 73. The bottom face of the repair assembly will be concave with radius to order.

Fig. 42 is a perspective view of one embodiment of the repair washer system of the present invention.

Figs. 43 45 are top plan, front elevation and bottom plan views of the repair washer body of Fig. 42.

Fig. 46 is a perspective view of another embodiment of the repair washer system of the present invention.

Detailed Description of the Preferred Embodiment Solution Loader Spreader As seen in Figs. 18 23 the bolt 20 with forged head shape 30 is designed to increase contact by spreading the load area in the taper neck both radially and axially even with mismatched neck angles. This design introduces additional bolt head forged surfaces 30 with ridges 31, which project into the vacant clearance zones and tough the liner hole surfaces 12 uniformly around the faying surface of the bolt head. These projecting areas or ridges 31 are dimensioned so that they deform under load when tightened against the harder steel liner surface 12. As the bolt 20 is tightened, plastic deformation takes place resulting X:\pw.g patM1538-97aa.doc 1 in additional radial and axial surface contact, until full clamp load is reached, at which 2 time this load will be spread over a larger and more uniform surface at the neck. Figs.

3 10-23 show the alternative round, elliptical, square, oblong, spherical, and rectangular 4 neck and head shapes of the present invention.

Alternative Insert Mode 6 As best seen in Figs 24-27, using the same theory, spreader inserts 40 are used 7 to fit between a regular standard head bolt 20,21 and the liner hole 10,12. Two inserts 8 40 with ridges 41 are temporarily attached, one at each neck area on the bolt, and held 9 in place with an elastic band. Once the bolt head is assembled into the liner hole,, the inserts will align themselves to spread load surface contact. Spreader inserts may be .1 added to existing standard liner bolts, to increase their load supporting capabilities.

i2 The choice of using a forged spreader bolt (Figs 18-23) or spreader inserts (Figs 24- 3 27) would depend on the application and customer preference.

14 Solution With Metal-to-Metal As best seen in Figs 28-30, the system of the present invention will allow the 16 joint to be metal-to-metal and the seal to do its function independently. It will also apply 17 the nut 23 load directly on the shell 1 through hardened serrated teeth 53 so that the 18 assembly cannot move to loosen. The rubber or neoprene 0-ring seal in O-ring groove 19 51 on the underside of repair washer 50 stays on the periphery of washer 50 away from the metal-to-metal contact area 53 where the actual load 21 application is made. Another smaller 0-ring (not shown) in annular groove 54 (Fig. 29) 22 seals the inner hole and the threads.

1 Special Repair Plate and Washer to Repair Enlarged 2 Holes in Liner Shell 3 As best seen in Figs 30-41 a further aspect of the invention includes the 4 provision of a special repair plate and special repair washer 60 which allows repair of enlarged holes in the liner and shell caused by dynamic movement resulting from 6 loosening of the bolt in place when prior art bolts were used. The improvement of the 7 present invention includes a repair plate 61 having a central bore 62 (Fig. 30) and a a plurality of socket holes 63. The top surface 64 of the repair plate 61 is flat. the bottom 9 surface may be curved to match the shell Those skilled in the art would readily understand that the improved bolt of the present invention would be inserted through the hole in the liner 10 and the hole in the shell 1 through the plate 61 which is held in place by bolts (not shown) through socket holes 63, which bolts go through plate 61 and into shell 1 but not through shell 1 (to avoid causing a hole which only then would also have to be sealed). A repair washer 50 (Fig. 29) or in alternate form as shown by T5 repair washer 60 (Fig. 30) is used to provide metal-to-metal contact and the improved o*o* 16 sealing as described above.

17 The process for making repair plate 61 is demonstrated in 18 Figs 34-41. After socket holes 63 are drilled, the holding bolt is removed and replaced 19 by a bolt 20 of the present invention having forged areas 30 or alternatively using load spreader inserts 40 to which is then secured repair washer 50,60 and nut 23 as 21 described above. A center drill 71 held in place by center drill bushing 72 allows socket 22 holes 63 to be precisely drilled while tap drill bushing 73 coupled with drill stopper 1 bushing 74 superimposed on top of tap drill bushing 73 as shown in Fig. 41 controls the 2 depth to which the holes are drilled into the shell 1 but not through shell 1. When all 3 of holes 63 are drilled, plate 61 is held in place by bolts through socket holes 63 into 4 shell 1. First, repair plate 61 is superimposed over the central bore 11 which goes into the shell 1 and liner 10 and is held in place by a large bolt through bore 11 to prevent 6 repair plate 61 from moving while socket holes 63 are being drilled.

7 The forgoing description of a preferred embodiment and best mode of the 8 invention known to applicant at the time of filing the application has been presented for 9 the purposes of illustration and description. It is not intended to be exhaustive or to .o limit the invention to the precise form disclosed, and obviously many modifications and A-1 variations are possible in the light of the above teaching. The embodiments were '12 chosen and described in order to best explain the principles of the invention and its S practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated.

S Sgo

Claims (37)

1. A repair washer for enlarged holes having: a shaped body having a top major surface and a bottom major surface and a central bore therethrough, an indentation in the bottom major surface constructed and configured to receive a seal, and a plurality of teeth integral with the bottom major surface inboard of the indentation constructed and configured for gripping a surface which is to be sealed.

2. A washer as claimed in claim 1 wherein the indentation is a recess at a periphery of the bottom surface.

3. A washer as claimed in claim 1 wherein the indentation is an area of reduced dimension at a periphery of the bottom surface outboard of the teeth.

4. A washer as claimed in claim 3 wherein the reduced dimension is a width less than the width of the body. A washer as claimed in claim 3 wherein the reduced dimension is a reduced diameter portion.

6. A washer as claimed in any one of claims 1 to 5 wherein the seal is a rubber gasket.

7. A washer as claimed in any one of claims 1 to 5 wherein the seal is an o- ring. X:\pwg pat\41538-97aa.doc

8. A washer as claimed in claim 1 wherein the indentation is an annular groove in the bottom major surface being located away from the central bore and being constructed and configured to cooperate with a bolt through the central bore and through a fastener overlying the top surface to seal the central bore at the bottom surface.

9. A washer as claimed in claim 8 wherein the seal is an o-ring. A washer as claimed in claim 8 wherein the overlying fastener is a washer and nut combination.

11. A washer as claimed in any one of claims 1 to 10 wherein the teeth are serrated and are constructed and configured to prevent movement and subsequent loosening of the washer while the bottom seal is effected when the washer is tightly secured to the sealed surface by an overlying fastener.

12. A washer as claimed in any one of claims 1 to 11 wherein the shape of the body is a shape selected from the group including round, elliptical, square, rectangular, oblong or partially arcuate.

13. A washer as claimed in any one of claims 1 to 12 wherein the bottom major surface portion is flat.

14. A washer as claimed in any one of claims 1 to 12 wherein the bottom major surface portion is curved to cooperate with a curved surface which is to be sealed. A washer as claimed in any one of claims 1 to 14 wherein the bottom major surface is a load surface and the indentation is being constructed and configured to effect a bottom seal on the periphery of the load surface. X:%pwg- patv41538-97aa.doc

16. A washer as claimed in any one of claims 1 to 15 further including: a recessed indentation in the top surface constructed and configured to receive a seal.

17. A washer as claimed in claim 16 wherein the recessed indentation is located near the central bore and is constructed and configured to cooperate with a bolt through the central bore and through an overlying fastener to seal the central bore at the top surface.

18. A washer as claimed in claim 17 wherein the overlying fastener is a washer and nut combination.

19. A washer as claimed in any one of claims 1 to 18 wherein the top major surface has a chamfered edge. A repair washer for sealing a hole having: *o a body having a top major surface and a bottom major surface and a central bore therethrough, the top major surface constructed and configured to cooperate with an overlying fastener having a first sealing member for sealing the central bore at the top major surface, S an indentation in the bottom major surface constructed and configured to receive a second sealing member for sealing the central bore at the bottom major surface, and a plurality of teeth inboard of the indentation and integral with the bottom major surface constructed and configured for gripping a surface surrounding the hole which is to be sealed. X:Apwg pat1538-97aa.doc

21. A washer as claimed in claim 20 wherein the indentation is a recess at a periphery of the bottom surface.

22. A washer as claimed in claim 20 wherein the indentation is an area of reduced dimension at a periphery of the bottom surface outboard of the teeth.

23. A washer as claimed in claim 22 wherein the reduced dimension is a width less than the width of the body.

24. A washer as claimed in claim 22 wherein the reduced dimension is a reduced diameter portion. o* A washer as claimed in claim 20 wherein the indentation is in the bottom major surface being located near the periphery of the bottom major surface.

26. A washer as claimed in claim 25 wherein the overlying fastener includes in sequence from outboard to inboard a nut, a metal washer and the first sealing member for sealing the central bore at the top major surface.

27. A washer as claimed in claim 26 wherein the metal washer is recessed and receives the first sealing member therein to effect a seal axially between a. the top surface of the body and the overlying metal washer and radially between a bore of the sealing member and an outer circumference of a bolt passed through the hole.

28. A washer as claimed in claim 20 wherein the indentation in the bottom major surface is located away from the central bore relative to the sealing member to be applied at the top major surface. X:pwg pat\41538-97aa.doc

29. A washer as claimed in claim 28 wherein the overlying fastener includes in sequence from outboard to inboard a nut, a metal washer and the first sealing member for sealing the central bore at the top major surface.

30. A washer as claimed in claim 29 wherein the metal washer is recessed and receives the first sealing member therein to effect a seal axially between the top surface of the body and the overlying metal washer and radially between a bore of the sealing member and an outer circumference of a bolt passed through the hole.

31. A washer as claimed in claim 20 wherein the teeth being serrated and being constructed and configured to prevent movement and subsequent loosening of the washer while the top and bottom seals are effected when the washer is tightly secured by the overlying fastener to the surface surrounding 15 the hole to be sealed.

32. A washer as claimed in claim 20 wherein the bottom major surface portion is curved to cooperate with a curved surface which is to be sealed. .o

33. A repair system for sealing a hole in a surface including: a fastener bolt disposed in the hole from one direction and having an end extending outboard of the surface, S a body having an outboard major surface, an inboard major surface, and a central bore receiving the end of the bolt therethrough, a first sealing member, a metal washer and a fastener nut secured to the end of the bolt in that order from the other direction sealing the central bore at the outboard major surface of the body, an indentation in the inboard major surface of the body receiving a second sealing member sealing the central bore at the inboard major surface of the body, and X:WPg patW1538-97aa.doc a plurality of teeth integral with the inboard major surface of the body between the indentation and the central bore of the body gripping the surface surrounding the hole.

34. A system as claimed in claim 33 wherein the indentation is a recess at a periphery of the bottom surface. A system as claimed in claim 33 wherein the indentation is an area of reduced dimension at a periphery of the bottom surface outboard of the teeth.

36. A system as claimed in claim 35 wherein the reduced dimension is a width less than the width of the body. 6 ;6

37. A system as claimed in claim 35 wherein the reduced dimension is a 06 reduced diameter portion.

38. A system as claimed in claim 33 wherein the teeth are serrated to prevent movement and subsequent loosening of the system.

39. A system as claimed in claim 33 wherein the bottom major surface portion is curved to cooperate with a curved surface which is to be sealed. 6 A system as claimed in claim 33 further including: an indentation near the central bore in the outboard major surface of the body receiving therein the first sealing member to seal the central bore of the body at the outboard major surface of the body. X:\pwg pat%41538-97aa.doc

41. A system as claimed in claim 33 wherein the top and bottom seals are o- rings.

42. A system as claimed in claim 33 wherein the top and bottom seals are rubber gaskets.

43. A system as claimed in claim 33 wherein the metal washer is recessed and receives the first sealing member therein to effect a seal axially between the top surface of the body and the overlying metal washer and radially between a bore of the sealing member and an outer circumference of the fastener bolt.

44. A repair washer for sealing a hole substantially as herein described with reference to the accompanying drawings. 15 45. A repair system for sealing a hole substantially as herein described with reference to the accompanying drawings. 0@ 0S S S@ 5 @0OS CS C OS C C S DATED: 26 April, 2001 PHILLIPS ORMONDE FITZPATRICK 0O OS e 0 60 S 00 Attorneys for: RONALD C. CLARKE X:pwg pat\41538-97aa.doc