Excavating Tool And A Bit For Use Therewith

Abstract

An excavating tool and a bit for use therewith in which the bit is of small dimensions and is mounted in a block in which the bit is rotatable and which block is configured in such a manner that it can be welded to various types of holders so that a plurality of blocks and bits mounted on a holder make an excavating tool of selected style and size.

Description

The present invention relates to excavating tools and to bits to be used therewith and is particularly concerned with excavating tools made up from small bits and support blocks therefor with the blocks mounted on a support member.

Excavating tools and bits therefor are known. Further, bits of the pick type in which the bit is symmetrical by a longitudinal axis and has a sharp point on the leading end and is rotatably supported in a block are known. Heretofore, however, the bits and blocks have been relatively large and the size limitations thereby imposed on the excavating tool has precluded the manufacture of excavating tools for boring small diameter holes and for taking cores and the like.

The present invention is particularly concerned with excavating tools utilizing support blocks and pick-type bits rotatable therein in which the bits are relatively small and wherein the blocks are especially configured to facilitate the mounting thereof on a supporting member forming a part of the excavating tool.

Another object of the invention is the provision of a pick-type bit of the nature referred to so configured as to permit the mounting of a massive wear resistant element in the working end thereof.

These and other objects and advantages of the present invention will become more apparent upon reference to the following detailed specification taken in connection with the accompanying drawings in which:

FIG. 1 is a side view of an auger or boring tool constructed according to the present invention.

FIG. 2 is an end view of the tool of FIG. 1.

FIG. 3 is an end view of a tool similar to what is shown in FIGS. 1 and 2 but wherein the tool comprises swingable wing cutters at the outside.

FIG. 4 is an end view of a small diameter auger according to the present invention.

FIG. 5 is an end view of a core barrel utilizing bits according to the present invention.

FIG. 6 is a side view partly in section showing one type of bit and block according to the present invention.

FIG. 7 is an end view looking in from the left side of FIG. 6.

FIG. 8 is a view partly in section showing another type of pick-type bit according to the present invention.

BRIEF SUMMARY OF THE INVENTION

According to the present invention, an excavating tool is constructed utilizing a support member which may be in the form of a back plate or ring and one one side of which is mounted, preferably, by welding, a plurality of blocks having bores therein. Pick-type bits are provided having cylindrical shanks rotatably receivable in the bores with the bits having pointed leading ends preferably provided with hard wear resistant inserts formed of, for example, cemented tungsten carbide.

The bits are held in the blocks against any substantial amount of axial movement therein while being permitted to rotate in the blocks. The picks, when presented to a formation to be reduced, are driven against the formation and will rotate in the respective blocks and will, thus, wear off evenly and remain sharp and pointed throughout the life of the respective pick.

In one form of the invention, each pick has a massive pointed element formed of cemented tungsten carbide, or a like hard wear resistant material, mounted on the tip end thereof and which element has extremely long life and pronounced formation reducing capabilities. The support block for each pick is especially configured to facilitate mounting of the block on the support member in various angularly related positions so that the pick-type bits supported by a group of blocks on a support member can be so arranged that the point ends thereof are distributed relative to the formation to be reduced and are, therefore, efficient in reducing the formation.

Due to the small size of the pick-type bits and the support blocks therefor, small diameter auger tools can be made as well as core barrels, both of which are outside the scope of the conventional larger type pick-type bit and support block.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the drawings somewhat more in detail, in FIGS. 1 and 2, there is shown an auger consisting of a support plate or backing plate 10 from one side of which extends a drive shank 12 which may, for example, be hexagonal. Drive shank 12 is adapted for engagement by a driver which rotates plate 10 on the axis thereof while pressing the plate 10 in a direction away from the side from which driver 12 projects.

Plate 10 in the center thereof has fixed thereto a spacer or chuck 14 to the outer end of which is attached a pilot bit 16 which may consist of a body of steel with a transversely extending blade 18 fixed therein and which blade may advantageously consist of cemented tungsten carbide or a like hard wear resistant material.

According to the present invention, there is mounted on the plate 10 in circumferentially spaced relation on the same side as the pilot cutter, a plurality of support blocks 20 and in each of which there is rotatably mounted a pick-type bit 22 which at its outer free end is provided with a hard wear resistant insert 24 and which may, for example, consist of cemented tungsten carbide or the like.

Each pick-type bit has a shank 26 extending through an axial bore in the respective block 20 and on that portion of shank 26 which protrudes from the back of the block there is provided an annular groove into which a snap ring 28, either of metal or plastic, is mounted and which snap ring 28 prevents the bit from coming out of the block but does not in any way inhibit the pick from rotation in the block. The ring 28 can also be in the form of a rubber-like O-ring.

As will be seen in FIG. 2, the bits are so distributed as to cover a substantial radial range relative to the axis of the auger so that the formation to which the auger is presented is adequately reduced over the entire diameter of the auger.

It will be appreciated, upon reference to FIG. 2, that there is a bit 22a having its point radially innermost, and a bit 22b having its point disposed radially outwardly from the point of bit 22a and two bits 22c having their points radially outermost and both running on about the same circle and forming gauge cutters. The auger according to FIGS. 1 and 2 might, for example, be arranged to cut about a 4 inch diameter hole.

FIG. 3 shows an arrangement for cutting a somewhat larger hole, and in this view a back plate 30 is provided from which a pilot cutter 32 protrudes in the axial direction on one side. On the same side of back plate 30, there is mounted in radially and circumferentially distributed relation a plurality of blocks 34 each having therein a respective pick-type bit 36.

Further, in at least two circumferentially distributed positions, plate 30 carries a U-shaped wing cutter support 37, each of which has mounted thereon a further block 38 with a respective pick 40 therein. The auger shown in FIG. 3 is adapted for rotation in the direction of arrow 42 during a working operation, and this will cause the wing cutters referred to to swing to a radially outermost position and determine the gauge of the bore being formed.

When the auger is rotated in the reverse direction, however, the wing cutters swing inwardly, as shown in dot-dash outline at the bottom of FIG. 3, and this provides ample clearance to permit the auger to be retracted from a bore, or to be introduced into a bore from which it has been withdrawn for the replacement of tools. When the wing cutters in FIG. 3 are swung to their radially outer positions, a firm bearing of the wing cutters on plate 30 occurs in the regions indicated at 44 so that the wing cutters are solidly supported during cutting operations.

FIG. 4 shows an auger for a small hole, for example, about 3 to 31/2 inches. In FIG. 4, there is a base plate member 50 and mounted thereon in circumferentially distributed relation are blocks 52, each of which rotatably supports a respective pick-type bit 54. In FIG. 4, the point ends of the pick-type bits are distributed radially so that each works in a respective radial zone of the bore being formed. Only one bit in the modification of FIG. 4 operates as a gauge cutter as opposed to the two bits which serve as gauge cutters in each of the modifications of FIGS. 2 and 3.

The small size of the picks and blocks enable the bit and block of the present invention to be utilized for forming core barrels. For example, in FIG. 5, a ring 60 is provided and fixed thereto in circumferentially spaced relation are blocks 62 each having a respective pick-type bit 64 mounted therein. The axes of the pick-type bits are inclined with respect to the central axis of ring 60 so that the desired radial range is covered. In FIG. 5, the core taken is that region disposed radially inwardly from the two innermost pick-type bits.

FIGS. 6 and 7 show more in detail a typical block and pick-type bit of the nature illustrated in any of the modifications previously described. In FIGS. 6 and 7, the block is indicated at 70 and will be seen to have a central axial bore 72 in which the shank 74 of the respective bit 76 is rotatably mounted. The shank protrudes from the back of the block and has a snap ring 78 mounted in a groove provided in the shank at that region.

As opposed to the larger type blocks employed with pick-type bits, the block 70 in FIGS. 6 and 7 has a flat front face 80 and the pick-type bit 76 has a shoulder 82 that engages face 80 to support the working thrusts imposed on the bit. The shoulder 82 is formed by an enlarged forward end 84 formed at the front end of shank 74 and integral therewith. Enlarged forward end 84 has a bore 86 extending therein from the front end and bore 86 receives the shank 88 of a massive hard wear resistant insert 90 which, as mentioned, may be formed of cemented tungsten carbide or the like. The outwardly protruding end of insert 90 is conically formed and tapers into a point at 92.

The block 70 has a dependent portion 94 which on the rear side at 96 inclines upwardly at an angle of about 45.degree.. As will be seen in FIG. 7, the sides of the dependent portion 94 as at 98 are also inclined upwardly and outwardly at angles of about 45.degree.. The respective angles can be varied, but the provision of the inclination on the dependent portion 94 of the block is of importance because it facilitates positioning the blocks on the various support members provided therefor and the fixing of the blocks to the support members as by welding.

FIG. 8 illustrates a pick-type bit similar to that of FIGS. 6 and 7 except that the bit 100 in FIG. 8 has a forward portion 102 axially longer than the forward portion 84 of the bit of FIGS. 6 and 7. The forward portion 102 of the bit of FIG. 8 has a bore 104 and a cylindrical insert 106 of cemented tungsten carbide or the like is mounted therein. This insert is also pointed on the forward end.

The inserts in all cases are advantageously brazed in position, but if suitable machining and manufacturing tolerances are observed, the inserts can also be mounted in the bores therefor with a press fit. Brazing is preferred because if the bodies of the bits wear away in use and expose the sides of the inserts that are normally embedded in the body, the inserts will be held in place by the brazing material and will not readily be knocked out of the body of the bit.

The bits can be used for drilling vertical holes as well as horizontal holes.

Modifications may be made within the scope of the appended claims.

Claims

What is claimed is:

1. In a mining tool; a bit having a bit body with a cylindrical shank adapted to be rotatably received in a bore in a support member, a substantially cylindrical head portion larger in diameter than said shank integrally connected to the forward end of the shank and coaxial therewith, an annular shoulder at the juncture of said shank and head portion and facing toward the shank end of the bit, said head portion being substantially shorter in the axial direction than said shank, said head portion having a minor part of the axial length thereof at the forward end tapering inwardly, a cylindrical recess coaxial with said head portion extending axially into said forward end of the head portion and having an axial length greater than half the axial length of the head portion and a diameter substantially greater than half the diameter of said shank, and a massive insert of hard wear resistant material having a shank portion fixed in said recess and a working portion integral with the shank portion at the forward end thereof and protruding forwardly from the forward end of said head portion of the bit body, said working portion being substantially larger in diameter than said shank portion of the insert and symmetric about the axis of the bit body and tapering inwardly in the forward direction to a pointed end, said insert at the juncture of said shank portion and working portion thereof having an annular flange region facing the forward end of the head portion of the bit body and in abutting engagement therewith, the working portion of said insert being substantially as long in the axial direction as said head portion of the bit body, said shank of said bit body having annular groove means formed therein to receive a keeper element for retaining the bit in assembled relation with a support member.

2. A mining tool according to claim 1 in which each of said shoulder and flange region is disposed in a plane perpendicular to the axis of the bit.

3. A mining tool according to claim 1 in which said working portion has a larger diameter cylindrical first region at the rearward end adjacent the forward end of the head portion of the bit body, a second intermediate region tapering inwardly in the forward direction at a first angle, and a third region at the forward end tapering inwardly in the forward direction at a second angle greater than said first angle, said third region terminating at the forward end in said pointed end.

4. A mining tool according to claim 1 in which said annular shoulder is disposed in a plane perpendicular to the axis of the bit body, and a support member in the form of a block having a bore for receiving the shank of the bit and a front end disposed in a plane perpendicular to the axis of the bore for engagement with said shoulder.

5. A mining tool according to claim 4 which includes a ring rotatable on a central axis, a plurality of said blocks mounted on one axial side of said ring in circumferentially spaced relation and all having the axes of the bores therein inclined in one and the same circumferential direction of said ring, the axes of said bores being inclined at different angles to the axis of rotation of said ring when the ring is viewed in the axial direction to dispose the point ends of the bits in the blocks in distributed relation over a radial range which extends from radially inside the ring to radially outside the ring whereby the bits in said blocks will take a kerf radially wider than said ring whereby said tool is adapted for taking a core.