CZ279561B6 - Pick for slitting machines - Google Patents

Abstract

The carbide backing tip (5) has at least one end edge (6), one top edge (9), a bearing surface (12), a back (20), a rear wall (8, 11, 19) and a front wall (13). The tip (5) consists of a forward main portion (14) and a rear portion (15), wherein the spine (20) is located in the extension of the rear portion (15) and the length of the tip (5) determined by the distance of the top edge lines (A, C) is approximately twice the height of the leading edge (6), determined by the distance of the leading edge lines (D, E) on the front edge (6). The first apex plane (10) intersects with the second rear wall (11) and forms the apex cutting edge (9) of the main portion (14). The third rear wall (19) intersects with the dorsal wall (18) and forms a dorsal lip (17), the third rear wall (19) adjoining the second rear wall (11) of the main portion (14) and forming a sharper angle to the base in the edge (D) than the angle of the second rear wall (11)

Description

Knife for mining machines

Technical field

BACKGROUND OF THE INVENTION The present invention relates to a carbide blade for mining machines for the extraction of various minerals.

BACKGROUND OF THE INVENTION

Mining, such as coal, uses industrial mining machines of various types, fitted with radial or tangential knives. The tools are made of steel with holes for seating knives, which are inserted into the holes and then brazed. For knives of conventional construction, after 10 to 20% of the blade material has worn, the steel is exposed and rubbed against the mineral and / or rock that is below or above the mineral vein without effective extraction and undesirable minor pieces of rock. If coal is mined, the defect is even more dangerous, because methane is released during mining, which often leads to spontaneous ignition in the so-called ignition spark zone behind the cutting edge due to increased tool temperature. This leads to the need for ventilation or the deployment of a water cooling system, which entails increased costs. In addition, the blades wear rapidly, which reduces mining efficiency and requires blade replacement - usually after 3-4 shifts in coal mining. This operation requires about an hour of work, as the mining machine has about 50 knives.

SUMMARY OF THE INVENTION

The aforementioned drawbacks are largely eliminated by a carbide blade, which is characterized in that the rear apex of the rear of the cutting edge is at a greater angle to the apex plane than the front apex of the front. The heel of the rear portion is bounded by a rear edge that is parallel to the front wall of the front portion, and further with a chamfered edge beveled towards the rear bearing surface.

The total end face of the cutting edge is formed by a pair of chamfered end walls that converge towards the front plane.

The knife for mining machines of the invention has a longer lifetime and limits the spontaneous ignition of methane.

Tests have shown that the blades of the present invention will not wear the blade and contact it with the rock earlier than 50% of the blade wear. This implies that the service life is extended by about 50% compared to the standard version. In addition to reducing the number of knives required to extract the same amount of rock as before, additional savings are also achieved by reducing the time required to replace mandrels by half. The number of steps required to operate one operator is decreasing and the demands for underground transport are also reduced.

BRIEF DESCRIPTION OF THE DRAWINGS.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of a radial blade provided with a carbide blade; FIG. 2 shows a tangential blade.

-1GB 279561 B6

DETAILED DESCRIPTION OF THE INVENTION

The mine knife is forged from steel and has a rectangular shank 2, adapted to fit into a holder where it is fixed by welding. These holders are used for mining machines for mining or tunnel excavating machines. The shank 2 passes to the extended support head 3, which has a structure adapted to whether it is a radial or tangential knife.

In the knife head 3 there is an L-shaped recess 4 for the carbide blade 5.

The carbide blade 5 consists of a total end face 6, which is formed by a pair of tapered end faces 7 relative to plane A, which converge towards the end plane 8. The total front apex surface 9 is also formed by a pair of tapered end faces 10, relative to apex plane D converging to the front apex plane

The lip 5 also has a flat front abutment surface 12 on which a pair of side walls 13 abut. In the region between planes A and B there is a front portion 14 of the lip 5, which is a known standard part of the lip. As soon as wear occurs below this line 14 in the conventional knife 14, undesired contact between the base steel material of the bearing head 3 and the mineral is caused. However, the lip 5 according to the invention comprises an elongated rear portion 15 in the region between planes B and C. The total length of the lip 5 is determined by the region between planes A and C, and this distance is about twice as high as determined by the distance between the planes D and E. The front portion 14 and the rear portion 15 of the cutting edge 5 are manufactured as one part by the technology of sintering and pressing metal carbide powders.

The rear portion 15 has a rear abutment surface 16, which adjoins the flat front abutment surface 12 of the front portion 14 of the lip 5. The total rear apex surface 17 is again formed by a pair of tapered dorsal walls 18 that converge to the rear apex wall 19, which it connects to the front apex plane 11 of the front portion 14, but at a greater angle to the apex plane D, as can be seen from both figures. The rear portion 15 is terminated by a foot 20 of the lip 5 which is bounded by a rear edge 21 that is parallel to the front wall 8 of the front portion 14 and further with a chamfer 22 facing the rear bearing surface 16.

Thanks to this arrangement, the wear limit of the cutting edge 5 is moved up to the L2 line, which has also been proven by practical tests.

Industrial applicability

The blades for mining machines according to the invention are suitable for use in rock mining or tunnel drilling. The blade shape can be used for both radial and tangential blades.

Tests have shown that in the knife according to the invention, which consists of a front portion 14 and a rear portion 15, the rear apex 19 forming a greater angle with the apex plane D than the apex apex 11, there is no undesirable contact between the base material of the support head and the mineral before the L2 line, which is about half the cutting edge height, is crossed.

Claims (2)

A knife for mining machines, the cutting edge of which comprises a front part and a rear part, the length of the cutting edge being approximately twice as large as its height, and a pair of bevelled front walls converging at the front wall, characterized in that the rear apex wall (19) ) of the rear part (15) of the cutting edge (5) forms a greater angle with respect to the apex plane (D) than the angle of the front apex plane (11) of the front part (14). Knife according to claim 1, characterized in that the heel (20) of the rear part (15) is bounded by a rear edge (21) which is parallel to the front plane (8) of the front part (14) and further with a chamfer (22). ), bevelled towards the rear bearing surface (16).