US3750772A

US3750772A - Rotary cutters

Info

Publication number: US3750772A
Application number: US00212502A
Authority: US
Inventors: P Venter
Original assignee: McDonnell P Ltd
Current assignee: McDonnell P Ltd
Priority date: 1971-06-28
Filing date: 1971-12-27
Publication date: 1973-08-07
Anticipated expiration: 1990-08-07
Also published as: ZA714204B; AU3727571A; ZM19171A1; CA946429A; AU441543B2

Abstract

The invention provides for means for mounting a rotary cutter so that the cutter is reclaimable or more easily reclaimable than hitherto known to the applicant. By this means the journal and load pin rotatably supporting the cutter is made in one. Furthermore there is provided in a saddle supporting the journal, an angular notch to restrain the journal against rotation. Still further, there is provided a saddle to support the journal, the saddle having a detachable limb having an angular notch to restrain the journal against rotation.

Description

United States Patent 1 Venter [4511 Aug. 7, 1973 1 ROTARY CUTTERS [75] Inventor: Pieter Lawrence Venter,

Johannesburg, Transvaal Province, Republic of South Africa [73] Assignee: Paddy McDonnell (Proprietary) Limited, Johannesburg, Transvaal Province, Republic of South Africa 2] Filed: Dec, 2 711- [21] PP No.: 212,50

[30] Foreign Application Priority Data June 28, 1971 Republic of South Africa...... 4204 [52] US. Cl 175/364, 175/353, 175/371, 175/374, 175/347 [51] Int. Cl. E21c 13/00, E21c 23/00, 1521b 9/12 [58] Field of Search 175/334, 335, 357-361, 175/363, 364, 368, 344, 371, 372, 376, 53;

[56] References Cited UNITED STATES PATENTS 3,612,196 10/1971 Dixon 175/364 2,187,037 1/1940 Kirkpatrick 3,054,466 9/1962 Wagnon et a1 175/347 3,203,492 8/1965 Lichte 175/364 X 3,658,141 4/1972 Schumacher... 175/364 1,812,681 6/1931 Brauer 175/371 X 3,216,513 11/1965 Robbins et a1... 175/372 X 3,545,811 12/1970 Montacle 299/86 X 3,601,207 8/1971 Coski et a1 175/364 X 3,627,068 12/1971 Wagnon et a1... 175/347 X 3,633,691 1/1972 Talbert 175/344 X Primary Ex ominer- Pavid l-l P rovvn A tiomeysiTie lvalle Goldsmith, ldester Horvvitz et a1.

51 ""Aismer Theinvention providesiar inanfir mounting rotary cutter so that the cutter is reclaimable or more easily reclaimable than hitherto known to the applicant. By this means the journal and load pin rotatably supporting the cutter is made in one. Furthermore there is provided in a saddle supporting the journal, an angular notch to restrain the journal against rotation. Still further, there is provided a saddle to support the journal, the saddle having a detachable limb having an angular notch to restrain the journal against rotation.

4 Claims, 4 Drawing Figures SHEET 2 BF 2 FIGS. FICA.

ROTARY CUTTERS BACKGROUND TO THE INVENTION This invention relates to improvements in or relating to rotary cutters. The invention relates in particular to improved mountings for rotary cutters for drilling big holes such as shafts, raises and tunnels.

Rotary cutters for drilling big holes as presently known to the applicant are mounted for rotation about a tubular journal having a bore in which a load pin is received. The load pin is removably mounted in apertures provided through one or more limbs of a supporting saddle. In order to prevent rotation of the journal, the, journal is provided with a shoulder engaging some portion of the saddle. The lug is well above the centre line of the journal bore.

To remove the cutter from the saddle the load pin has to be withdrawn in an axial direction from the journal and from the apertures in the saddle. Since the cutter is mounted with very fine tolerances in the saddle it often happens that due to minimal wear or shock loads a bending movement is induced in the shoulder onthe tubular journal thereby causing fracture or deformation of the shoulder and/or the journal. Due to the very fine tolerances, the fracture or deformation makes it almost impossible to withdraw the load pin from the journal and from the apertures in the saddle when the cutter has to be removed. Dust particles together with water often also cause the load pin to seize. This necessitates flame cutting the saddle and cutter to remove the cutter, removing the saddle and repairing it. This is a laborious, as well as costly and wasteful operation as the cutter is always destroyed.

Furthermore, it often happens that the load pin works loose, whereby the cutter is forced out of the saddle and destroyed.

It is an object of the invention to mount a rotary cutter so as to overcome or at least to alleviate the above described difficulties.

According to the invention there is provided mounting means for mounting a rotary cutter having a bore, the mounting means including a journal-cum-load pin receivable in the bore of the cutter and including means to restrain the journal-cum-load pin against rotation.

The means to restrain the journal-cum-load pin against rotation may comprises an angular formation such as a lug onthe journal adapted to seat in a complebe rotatably mounted and being further adapted to restrain the journal against rotation.

Further according to the invention there is provided mounting means for mounting arotary cutter having a bore, the mounting means including a saddle having at 'least one detachable limb having an angular notch in which a journal is receivable for rotatably supporting the cutter.

The invention also extends to the combination of a rotary cutter and mounting means in accordance with the invention.

The invention still further extends to a drill bit for raise drilling which includes mounting means for a rotary cutter in accordance with the invention.

In order to permit deformation of that part of the saddle in whichthe angular notch is provided, a slot may be provided leading out of the notch into the saddle. The slot facilitates the clamping together of the opposed parts of the saddle defining the slot so that the lugs on the journal may be-clamped in the notch.

There may conveniently be provided a wearing pad to line at least that part of the notch along which the lugs on the journal are supported. The pad may be removable so as to be replaceable when worn. The wearing pad is preferably of a softer material than the journal lugs to prevent the journal from wearing, thus making the journal re-usable.

The wearing pad may be located in the notch in the saddle by providing a plurality of holes through the pad and by filling the holes with welding extending to the surface of the saddle. Any welding projecting from the holes is filed away or machined away flush with the surface of the pad.

The invention is now described by way of examples with reference to the accompanying drawings, in which z r FIG. I shows diagrammatically a plan view of a raise boring bit;

FIG. 2 shows an exploded view of a saddle and rotary cutter suitable for use in positions 3 to 8 of the bit shown in FIG. 1 or in positions of further bolt-on stages, or in larger boring heads such as tunnel boring heads;

FIG. 3 shows a side view of a rotary cutter and saddle suitable for use in positions 1 and 2 of the bit shown in FIG. I; and

FIG. 4 shows an end view of the cutter and saddle shown in FIG. 3.

Referring to FIG. 1, reference numeral 10 indicates generally a raise boring bit having a platform 12 and a stem 14. Rotarycutters marked 1 to 8 are mounted on the platform I 2. Although the drawing shows only eight cutters, a lesser or greater number of cutters may be mounted on the platfonn, or on an additional bolt-on stage. I

Referring to FIG. 2, reference numeral 16 indicates a saddle in which to mount a rotary cutter 18. The cutter 18 is offrusto-conical shape and may forinstance be any one ofthe cutters 3 to 8'shown inthe raise boring bit illustrated in FIG. 1. Along the periphery of the cutter 18 there may be provided cutting inserts 20.

Thecutter 18 is rotatably mounted on a journal 22 via

roller bearings

21 and 23. The endsof the journal 22 terminate in

rectangular lugs

24 and 26 through which are provided

bolt holes

28 and 30. Screw threads 32 are provided on one end of the pin to receive a locking nut (not shown). The cutter 18 :is axially located-on the

bearings

21 and 23 between this locking nut and an annular shoulder 34 on the other end of the journal.

The saddle 16 has two

limbs

36 and 38 in which there are provided rectangular notches 40 and 42 respectively. The notches are for receiving

thelugs

24 and 26 and for locating the journal 22 against rotation.

Bolt holes

44 and 46 extend through the

limbs

36 and 38 for receiving locking bolts 48 and 50. The locking bolts extending through the

holes

44 and 28 and through the

holes

46 and 30 lock the

lugs

24 and 26 to the saddle l6.

The base of each notch 40, 42 is lined with a replaceable wearing pad 52, 54 on which the

lugs

24, 26 are seated. The wearing pads are secured by providing holes 55 through them which are filled in with welding extending to the notch surface. Excess welding is filed away or machined away.

Slots

56, 58 extend from the notches 40, 42 into the

limbs

36, 38. The slots permit deformation of the

limbs

36, 38 and thus facilitate the clamping of the

lugs

24, 26 in the notches 40, 42.

In use, the load is transmitted from the rock face via the rotary cutter 18, the

bearings

21, 23, the journal 22, the

lugs

24, 26 and the wearing pads 52, 54 to the saddle 16. Thus the load is transmitted from the journal to the saddle well below the centre line of the journal, thereby eliminating the possibility of a bending movement being induced as in the arrangement of the prior art.

In order to remove the cutter l8 and journal 22 from the saddle 16, the locking bolts 48, 50 are loosened and are withdrawn from the

holes

44, 28 and 46, 30. The journal 22 may now be lifted out of the notches 40, 42. By unscrewing the locking nut (not shown) from the threads 32 the journal 22 may be withdrawn from the bore of the cutter 18.

The advantage of the notches 40, 42 in the saddle l6 is-that the journal 22 can be lifted out of the saddle. It is not necessary to withdraw the journal in an axial direction from the saddle. Reclamation of the cutter 18 is thus considerably facilitated over the known method of having to withdraw the pin in an axial direction from the saddle.

Referring to FIGS. 3 and 4, there is shown a rotary cutter 60 and its associated mounting for use in the positions l and 2 in the boring bit shown in FIG. 1. The cutter 60 is rotatably mounted via

roller bearings

62 and 64 on a journal 66. The cutter is axially retained in position on the journal 66 between a lockingnut 68 which is screwed onto the journal, and an annular shoulder 70 on the journal. The end 72 of the journal 66 is journalled in a bearing 74 in the boring stem 14, this journal end being hard-chromed to resist wear. The outer end 76 of the journal 66 is of an angular shape similar to the lug 24 in FIG. 2.

The lug 76 is receivable in a notch 78 in a support 80. Bolt holes are provided through the support 80 and the lug 76 for receiving a locking bolt 82 for clamping the lug 76 in the notch 78. A wearing pad 84 and a slot 86 similar respectively to the wearing pads 52, 54 and the

slots

56, 58 in FIG. 2, are provided in the support 80.

A flange 88 is provided at the base of the support 80 to seat on a complementary flange 90 fast with the platform 12. Bolt holes are provided through the

flanges

88 and 90 for receiving clamping bolts or cap screws 92 for clamping the flanges to one another. The flange 90 is so positioned that the level of its top face is below the periphery of the cutter 60 to permit the cutter to pass with clearance over the flange 90 when the cutter is removed.

When it is desired to remove the cutter 60 from the journal 66, the bolts or cap screws 92 are unscrewed and removed to free the

flanges

88 and 90 from one another. The whole cutter and journal assembly is now slid in an axial direction out of the bearing 74. The bolt 82 is removed and the lug 76 removed from the support 80. By unscrewing the locking nut 68, the cutter 60 may be withdrawn axially from the journal 66.

The advantage of the mounting arrangement shown in FIGS. 3 and 4 is just as in the case of the mounting arrangement illustrated in FIG. 2 that reclamation of the cutter 60 is facilitated. In order to remove the cutter from the stem 14 it is not necessary to withdraw the journal 66 axially from the cutter. Instead the procedure is followed as already described above. Costly lug removal from the bit body for repairs as is necessary in the prior art arrangement is thus eliminated.

A further advantage of the invention is that by providing a combined journal-cum-load pin, the separate tubular journal is eliminated and with it the difflcultie's in and problems caused by the known methodsof restraining the tubular journal against rotation.

A still further advantage of the invention is that the angular lugs and associated notches in the saddle lock the journal positively against rotation.

I claim:

1. Mounting means for mounting a rotary cutter having a bore, the mounting means including a saddle having at least one limb in which is provided an angular notch in which is receivable an end of a journal on which the cutter may be rotatably mounted the end of the journal being of a complementary angular crosssection so that the journal is restrained against rotation, aligned apertures being provided through the saddle and the angular journal end to receive a tie-bolt for clamping the angular journal end in the notch, there being provided a slot in the saddle limb having the notch and leading out of the notch to permit deformation of the saddle limb having the notch during clamping of the angular journal end in the notch.

2. Mounting means according to claim 1 in which the notch is rectangular in cross-section and in which the mounting means includes a flat wearing pad to line at least that part of the notch along which-the journal is supported.

3. Mounting means according to claim 1, in which the saddle has two limbs each limb being provided with an angular notch in which to receive a journal end having a complementary cross-section.

4. Mounting means for mounting a rotary cutter having a bore, the mounting means including a saddle having at least one detachable limb having an angular notch in which an end of a journal is'receivable for rotatably mounting the cutter, the end of the journal being of a complementary angular cross-section so that the journal is restrained against rotation, aligned apertures being provided through the saddle and the angular journal end to receive a tie-bolt for clamping the angular journal end in the notch, there being provided a slot in the saddle limb having the notch and leading out of the notch to permit deformation of the saddle limb having the notch during clamping of the angular journal end in the notch.

t t t i i

Claims

1. Mounting means for mounting a rotary cutter having a bore, the mounting means including a saddle having at least one limb in which is provided an angular notch in which is receivable an end of a journal on which the cutter may be rotatably mounted the end of the journal being of a complementary angular cross-section so that the journal is restrained against rotation, aligned apertures being provided through the saddle and the angular journal end to receive a tie-bolt for clamping the angular journal end in the notch, there being provided a slot in the saddle limb having the notch and leading out of the notch to permit deformation of the saddle limb having the notch during clamping of the angular journal end in the notch.

2. Mounting means according to claim 1 in which the notch is rectangular in cross-section and in which the mounting means includes a flat wearing pad to line at least that part of the notch along which the journal is supported.

4. Mounting means for mounting a rotary cutter having a bore, the mounting means including a saddle having at least one detachable limb having an angular notch in which an end of a journal is receivable for rotatably mounting the cutter, the end of the journal being of a complementary angular cross-section so that the journal is restrained against rotation, aligned apertures being provided through the saddle and the angular journal end to receive a tie-bolt for clamping the angular journal end in the notch, there being provided a slot in the saddle limb having the notch and leading out of the notch to permit deformation of the saddle limb having the notch during clamping of the angular journal end in the notch.