|Publication number||US3820848 A|
|Publication date||Jun 28, 1974|
|Filing date||Apr 2, 1973|
|Priority date||Apr 2, 1973|
|Also published as||CA993902A1, DE2406472A1|
|Publication number||US 3820848 A, US 3820848A, US-A-3820848, US3820848 A, US3820848A|
|Original Assignee||Kennametal Inc|
|Export Citation||BiBTeX, EndNote, RefMan|
|Referenced by (21), Classifications (8)|
|External Links: USPTO, USPTO Assignment, Espacenet|
United States Patent 8 [191 Kniff [111 3,820,848 1 June 28, 1974 1 ROTARY MINING TOOL KEEPER ARRANGEMENT THEREFOR  Inventor: Thomas J. Kniff, Bedfo'rd, Pa.
 Assignee: Kennametal Inc., Latrobe, Pa.
 Filed: Apr. 2, 1973  Appl. No.: 347,394
 References Cited UNITED STATES PATENTS 8/1968 Krekeler ..299/86 3/1970 Kniff ..299/86 3,650,565 3/1972 Kniffm, 299/86 Primary Examiner-Emest R. Purser Attorney, Agent, or Firm-Melvin A. Crosby [5 7] ABSTRACT A rotary mining tool in the form of a bit symmetrical about the longitudinal axis and having a cylindrical shank rotatably supported in a support block. Cooperating elements of abutment means on the bit and the block support axial loads imposed on the bit. The bit is releasably retained in the block while permitted to rotate therein by a keeper arrangement on the rear end of the shank of the bit and which is in the form of a resilient ring'on the shank of the bit at the back 'end of the block and a metal back up ring immediately behind the resilient ring.
11 Claims, 4 Drawing Figures 1 ROTARY MINING TOOL AND KEEPER ARRANGEMENT THEREFOR The present invention relates to mining tools, especially to rotary mining tools. More particularly still, the present invention relates to the combination of rotary mining tools and support blocks therefor and to keeper arrangements for holding the tools in the blocks.
A type of mining tool that has proved to be highly efficient in use is the pick type tool which is a rod-like member symmetrical about a longitudinal axis having a working point at one end and a support shank at the other end. The support shank is rotatably received in a support block with the support block being mounted on a drive member for driving the tool point end foremost into a formation to be reduced.
Advantageously, the axis of the tool is disposed somewhat angularly to the path in which the tool is driven and engagement of the tool with the formation being worked will cause the tool to rotate in the support block provided therefor whereby the point end of the tool. will wear down substantially uniformly in the peripheral direction and remain sharp for a prolonged periodof time.
While such tools operate, as mentioned, in a highly efficient manner, it is, nevertheless, the case that, in at least certain formations, the tool is exposed to nonuniform impact conditions when working which brings about a tendency for the tool to be subjected to a widely varying load in' the axial direction with the tool even tending at times to be thrust forwardly, or to tend to jump forwardly, in the supporting block therefor.
The tools are normally retained in the blocks by snaprings or the like mounted on the tool shank at the rear end of the block and, while snap rings are effective for retaining the tool in the block, the aforementioned conditions cause the snap rings to engage the back of the block'and to wear off the back of the block to the point that the tools develop a substantial amount of freedom of movement in the axial direction in the support blocks provided therefor.
The nature of the work done by such tools, namely, reducing hard formations, is such that a considerable amount of fine abrasive material is developed which will bring about rapid wear of the interengaging relatively moveable surfaces on the .tool and block if the abrasive material gets between these surfaces.
With the foregoing in mind, it is a primary objective of the present invention to provide an improved mining tool of the nature referred to in which the problems referred to above are substantially diminished.
Another object of the invention is the provision of a keeper arrangement for retaining a rotary mining tool in a support block which substantially eliminates erratic axial movements of the tool in the block.
Still another object of the present invention is the provision of the combination of a mining tool and a support block therefor and a keeper arrangement for retaining the tool in the block in which substantially all of the relatively moveable surfaces of the tool and block are protected from fine abrasive material developed during working operations.
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:
BRIEF SUMMARY OF THE INVENTION The tool arrangement according to the present inven- I tion comprises a rotary pick type bit or tool symmetrical about a longitudinal axis and having a working region at the forward end tapering inwardly to a point while at the rearward end the tool comprises a shank which is circular in cross section at every point therealong.
A support block is provided having'a bore therethrough and closely but rotatably receiving the shank ofthe tool with the-shank projecting outwardly from the support block at the rear. Monted on the shank at the rear face of the block is a keeper arrangement consisting of a resilient rubber-like ring which is closely .ad-
jacent to or in engagement, with the rearward face of the block and behind the resilient ring is a metal ring which holds the resilient ring securely in position. Advantageously, the shank is provided with an annular groove in which the aforementioned rings are seated.
- The tool may, furthermore, include a radial flange immediately adjacent the forward face of the support block and'the combination of this radial flange and the resilient ring at the rearward face of the block, substantially excludes fine abrasive material from the bore in the block thereby tending to prevent the development of an abrasive condition in the bore which would lead to accelerated wear of the tool and support block.
DETAILED DESCRIPTION OF THE INVENTION Referring to the drawings somewhat more in detail, in FIG. 1, 10 is a support block having a bore 12 extendingtherethrough with a forwardly facing inclined shoulder 14 formed in the bore intermediate the ends thereof. Block 10 has a forward face 16 and a rearward face 18 with eachface, at least in the region thereof surrounding the ends of bore 12, being perpendicular to the axis of the bore. Block also has lower portion 20 by means of which the block can be secured, as by welding, for example, to a driver.
Mounted in bore 12 is a tool generally indicated at 22 and symmetrical about the longitudinal axis. The forward end of the tool is the working region and tapers inwardly to a point. The forward end of tool 22 advantageously has an axial bore 24 therein in which is fixedly seated a hard wear resistant pointed element 26.
provided with a rearwardly facing shoulder 30 which abuttingly engages shoulder 14 formed in bore 12 of block 10.
The forward portion of tool 22 also has a radial flange 32 formed thereon which is in relatively closely spaced relation to forward face 16 of block 10. The flange substantially prevents fine grit and the like from access to the forward end of the bore while, furthermore, if one or both of shoulders 14 and 30 wear any substantial amount, flange 32 will engage the front face of the block and assume a portion of the working load imposed on the tool.
The forward portion of the shank is at one diameter and the rearward portion is at a smaller diameter and immediately behind rearward wall 18 of the block the rearward portion of the shank of the tool is formed with an annular groove 34. Seated in the annular groove is a resilient rubber-like ring 36 which is adjacent to or in engagement with the rearward face 18 of the block and behind ring 36 is a metal snap ring 38 also seated in the groove.
As will be seen in FIG. 2, resilient ring 36 maybe held in a condition of compression against the rearward face 18 of block but the degree of compressionis not so much that it would prevent the tool from rotat ing in the block. The resilience of ring 36 prevents abrasion of the rearward face of the block by engagement by a metal ring and, furthermore, tends to prevent the tool from jumping forwardly in the block when the tool breaks through a hard formation or the like by cushioning such movement.
FIG. 3 shows the resilient annular ring 36 and a representative metal snap ring 38 in perspective.
While the rearward end of the rearward portion of the shank is disclosed as having a groove therein which receives both the resilient ring 36 and the snap ring 38, it will be evident that the shank could be left free of grooves and the resilient ring mounted thereon and then held in place by a metal ring having radially inwardly projecting prongs which resiliently engage the surface of the rearward end of the rearward portion of the bit shank when pressed thereon.
Metal rings of the nature referred to are known, and when such a ring is mounted in place on the shank of the bit, it is concave toward the back of the support .block and is fixed to theshank of the bit but is removeable therefrom by the use of a proper tool.
Such an arrangement is shown in FIG. 4 wherein the bit shank is indicated at 40 and the bit block at 42. The resilient rubber-like ring, indicated at 44, is in this case large enough to fit over the outside diameter of the rearward portion of the bit shank. Behind resilient rubberlike ring 44 is a steel ring 46 consisting of radial outer annular portion and radially inwardly extending sharp teeth 48.
The inner tips of teeth 48 define a circle somewhat smaller in diameter than the rearward portion of shank 40 of the bit so that when ring 46 is pressed on the bit shank, at least the teeth 48 deflect rearwardly and, thus, hold ring 46 fixedly on the shank.
It will be understood that the teeth 48 will be circumferentially distributed about the inside of ring 46 in a known manner.
Modifications may be made within the scope of the appended claims.
What is claimed is: I
1. In a mining tool; a tool body having a longitudinal axis and'symmetrical about said axis, said tool having a working region on said axis at the forward end tapering into a point and a shank on said-axis at the rearward end, said shank beingcircular in cross sectionQrearwardly facing shoulder means formed on said shank in the region thereof between the forward end'of said shank and a point about midway of the length of the, shank for supporting the tool body during working operations, a resilient rubber-like ring on said shank near the rear end thereof, and a metal ring on said shank at the rear side of said rubber-like ring, each of said rings when mounted in said shank protruding radially outwardly from said shank.
2. A mining tool according to claim 1 in which the' working region of said tool body comprises a tapered material embedded in the tapered forward end of said body.
4. A mining tool according to claim 1 in which said shoulder is in about the middle of the length of said shank.
5. A mining tool according to claim 4 in which said shoulder tapers outwardly in the forwarddirection. I 6. A mining tool according to claim l-in which said shank is formed with a groove near the rear endand said rubber-like ring is seated in the forward end of said groove and said metal ring is a snapring seated in the rear end of said groove.
' 7. A mining tool according to claim 6 which includes a support block having a front face and a rear face and a bore extending through the block and also through said front and rear faces, said bore being adapted to receive said shank from the forward end of the bore, said block having a forwardly facing shoulder engaging the rearwardly facing shoulder on said shank, the rearward end of said shank protruding from the rearward end of said bore and said groove being disposed immediately rearwardly of the rear face of said block when the shoulder on said shank engages the shoulder on the block, the forwardly facing side of said rubber-like ring being adjacent the rear face of said block and said snap ring being adjacent the rearwardly facing side of said rubber-like ring.
8. A mining tool according to claim 7 in which said front and rear faces of said block in at least the region thereof adjacent to and surrounding said bore are perpendicular to the axis of said face, said tool body having an annular flange thereon with aradially disposed rearwardly facing side which is disposed in adjacent relation to said region of said forward face when said shank is in said bore and the shoulder on'said shank is in engagement with the shoulder on said block.
9. A mining tool according to claim 7 in which said rear face of said block in at least the region thereof adjacent to and surrounding said bore is perpendicular to the axis of said bore.
10. A mining toolaccording to claim 9 in which said resilient rubber-like ring islightly compressed between the rear face of said block and said snap ring.
11.A mining tool according to claim 1 in which said metal ring is a washer-like member having teeth distributed about the inside thereof for resilient gripping engagement with said shank.
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|EP0084418A2 *||Jan 10, 1983||Jul 27, 1983||Unicorn Industries Limited||Improved drill bit and method|
|U.S. Classification||299/107, 403/165, 175/354, 384/222|
|International Classification||E21C35/00, E21C35/197|