US3814482A

US3814482A - Cutting removal bit for undercutting machine

Info

Publication number: US3814482A
Application number: US00301887A
Authority: US
Inventors: A Bower; J Leighton
Original assignee: General Electric Co
Current assignee: Sandvik Rock Tools Inc
Priority date: 1972-10-30
Filing date: 1972-10-30
Publication date: 1974-06-04
Anticipated expiration: 1991-06-04

Abstract

A cutter bit of the type used in undercutting machines employed in mining has a projection on the side of the shank extending from a position near the shoulder or gage stop to a point near the cutting edge. The cutter bit is positioned in the socket of the undercutting machine with the projecting wiper or wipers on the sides of the bit. When the undercutting machine is in operation the cutting edge of the bit cuts chips and breaks out material from the face which falls underneath the machine cutter bar. The wiper projection then sweeps the cuttings from underneath the machine cutter bar thereby removing potential supporting material and enabling the undercut face to be broken up readily for efficient loading.

Description

United States Patent [191 Bower, Jr. et a1.

[ 1 June 4, 1974 1 CUTTING REMOVAL BIT FOR UNDERCUTTING MACHINE [73] Assignee: General Electric Company [22] Filed: Oct. 30, 1972 [2]] Appl. No.: 301,887

Primary Examiner-Ernest R. Purser 5 7 1 ABSTRACT A cutter bit of the type used in undercutting machines employed in mining has a projection on the side of the shank extending from a position near the shoulder or gage stop to a point near the cutting edge. The cutter bit is positioned in the socket of the undercutting machine with the projecting wiper or wipers on the sides of the bit. When the undercutting machine is in operation the cutting edge of the bit cuts chips and breaks out material from the face which falls underneath the machine cutter bar. The wiper projection then sweeps the cuttings from underneath the machine cutter bar thereby removing potential supporting material and enabling the undercut face to be broken up readily for efficient loading.

1 Claim, 4 Drawing Figures CUTTING REMOVAL BIT FOR UNDERCU'I'IING MACHINE BACKGROUND OF THE INVENTION In conventional mining, a basic production problem is a stuck cut." This is a face which has been undercut and then drilled and shot, but which fails to break up sufficiently for efficient loading. One of the major which fails to break up sufficiently for efficient loading. One of the major causes for this failure to break properly is the collection of cuttings from the undercut which partially fills up the space of the undercut thereby providing sufficient support to the face which prevents breakup of the supported face material by the explosives. Some coal mines make it a standard practice to double-cut each face in order to insure that the cuttings will be removed. This practice is costly and time-consuming. The present invention is directed to a cutter bit structure for use in anundercutting machine which will remove the cuttings from the undercut during a single undercutting operation.

SUMMARY OF THE INVENTION Undercutting machines for use in mines are comparable to very large and massive chain saws. They have a cutter bar with movable sockets for mounting cutter bits which serve as cutting teeth. Cutter bits of the type used in such machines have faces with cutting edges of very hard materials. Each bit has a shoulder portion and a shank portion. The shank portion fits into a socket which includes a meansfor retaining the bit in the socketThe shoulder portion serves as a gage stop which limits the depth of penetration of the bit into the socket.

The side of the cutter bit which will face the underside of the machine during operation is equipped with a wiper projection extending from near the shoulder to a point near the cutting edge. The wiper projection is substantially parallel to the shank, but could be slightly angled were the cutting bitnpositioned such as to re quire angularity for positive removal of the cuttings.

During operation of the undercutting'machine the cutting edge of the' bit is brought to bear against the material being cut. This material falls to the bottom of the cut where it is soon swept away by the wiper projections of the bits. Thus, there is clearance between the seam bottom and the undercut face. When the face is subsequently drilled and shot there is minimum material in the undercut to prevent breakup of the face.

Consequently, there is no need to apply a second undercut to the face.

DESCRIPTION OF THE DRAWING.

FIG. 1 is a longitudinal view of a cutter bit embodying the feature of this invention.

FIG. 2 is a view of the cutter bit of FIG. 1 looking toward the cutting edge of the bit.

FIG. 3 is a longitudinal view of an alternative form of cutter bit embodying the feature of this invention.

FIG. 4 is a view of the embodiment of FIG. 3 looking toward the cutting edge of the bit.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawing, the cutter bit of this invention consists of a head portion having a face portion ment of the shoulder portion 14 with the socket limits the depth of penetration of the shank portion [7 thereby insuring thatthe head portions of the cutter bits will extend outward the proper distance during operation of the undercutting machine.

Extending from the side portion 13 of the cutter head 10 is an elongated wiper projection 20. The projection 20 extends from a point near the shoulder 14 in a direction parallel with the longitudinal surfaces of the shank 17 to a point just short of the cutting edge 15. Normally this will be about three-quarters of the distance from the shoulder portion 14 to a cutting edge 15. The wiper projection 20 is composed of a tough metal or alloy and may be securely fastened to the-side of the head as by welding or may be forged as an-integral part of the shank. It extends downward from the side of the bit which will be on the underside of the undercutting machine a distance of one-quarter to one-half inch. The thickness will be of the order of one-quarter inch under normal circumstances and its length will be of the order of three-quarters of an inch. Obviously, the dimensions and shape may be varied in the practice of this invention.

During use, the cutter bits of this invention are placed in the sockets of an undercutting machine with the wiper projections of the bits on the underside of the cutters as they are positioned in the machine. During the operation of such machines the advancing cutting edges 15 of the bits dig into the face and remove material which drops to the bottom of the undercut. The advancing wiper projections 20 then pick up this material and sweep it in a forward direction to remove it from places where it might otherwise gather to provide support for the material above the undercut. Thus, when the undercut face is subsequently drilled and shot it readily breaks up and falls downard where it is picked up and removed. I

While the invention has been described. with reference to particular embodiments, it is obvious that there may be variations in structure which properly fall within the scope of the invention. Accordingly, the in vention should be limited in scope only as may be necessitated by the scope of the appended claims.

What I claim as new and desire to secure by letters patent of the United States is:

1. A cutter bit structure for an undercutter used in mining comprising:

a cutter bit head having a face portion, two side portions and a shoulder portion, said face portion defining a cutting edge of said bit structure during operation of the undercutter;

a bit shank having a front face and two sides extending from said shoulder portion on the side opposite said head, said shank serving to mount said bit structure in a socket member positioned on the undercutter;

and an elongated wiper projection extending from at least one side portion of said head adjacent said face, said wiper projection having a leading face in a plane substantially p rallel with the plane of the to the cutting edge of ti: face and serving to sweep front face of said shank, said wiper projection excuttings from the undercut during operation of the tending from the shoulder portion to about three undercutter. quarters of the distance from the shoulder portion

Claims

1. A cutter bit structure for an undercutter used in mining comprising: a cutter bit head having a face portion, two side portions and a shoulder portion, said face portion defining a cutting edge of said bit structure during operation of the undercutter; a bit shank having a front face and two sides extending from said shoulder portion on the side opposite said head, said shank serving to mount said bit structure in a socket member positioned on the undercutter; and an elongated wiper projection extending from at least one side portion of said head adjacent said face, said wiper projection having a leading face in a plane substantially parallel with the plane of the front face of said shank, said wiper projection extending from the shoulder portion to about three quarters of the distance from the shoulder portion to the cutting edge of the face and serving to sweep cuttings from the undercut during operation of the undercutter.