SU1328509A1 - Cutting bit for mining and earth-moving machines - Google Patents

Abstract

FIELD OF THE INVENTION The invention relates to the mining industry, namely to a tool for mining and earth moving machines. The goal is to increase the durability of the cutters for mining and earthmoving purposes and to reduce the consumption of hard metal. The cutter consists of a body (K) 1 and a carbide plate (P) 2. The front surface 3 P 2 is angled to the support surface 4 and the adjacent surface K 1. The thickness P 2 from the rear end 8 is 0.5- 0.7 thickness P 2 from the front end side 7. The rear end face 8 P 2 and the adjacent surface K 1 are inclined to the front surface 3 L 2 at an angle of 110-120. With this plate arrangement, at the time of chipping the frozen soil or rock chips, the component force at the front end of the plate decreases. This leads to a decrease in the stress of detachment in the weld joint and an increase in the strength of the tool. 5 il. (L with Figure 1 from to 00 cd about with

Description

one

This invention relates to the mining industry, namely to; cutters for mining and earthmoving machines.

The aim of the invention is to increase the durability of the cutters for mining and earth-moving machines and to reduce the consumption of cemented carbide.

Figure 1 shows a cutter for mining and earth-moving machines, a general view; figure 2 - diagram of the forces acting on the cutting part of the cutter; in fig. 5 - diagrams of normal stresses 6 on the front surface of a solid plate with different relative thickness of the plate from the back

butt to the thickness of the plate from the front ar

venous

, 5-07;

butt (respectively 1 and 0., 5),

The cutter consists of a body 1, on which a carbide plate 2 is fixed (for example, by soldering) with front 3 and support 4 surfaces, cutting edges 5 and front 7 and rear 8 ends. Front surface 3 of plate 2 is angled to the support surface 4 and the adjacent surface of the housing 1, and the thickness a of the plate 2. From the side of the rear end 8 is 0.5-0, 7 of thickness a of plate 2 from the front end 7, i.e. there is a ratio of a, (0.5o.0.7) a,

20

25

thirty

th aj and the front and ends within 0.5-0.7, the normal stresses from bending 6 on the front surface of the plate are distributed evenly along its entire length E, This thickness-thickness ratio makes it possible to create an equal-strength plate along the length of the weld seam (Fig .3), whereas, with the ratio a. / A, 1, the maximum tensile stresses 6 are observed at a certain distance 2 from the front end. plate (Fig, 4), and with respect to O ,, 5. the stress extremum is displaced to the rear end of the plate (Fig. 5),

By making the back end of the plate and the adjacent part of the body at an angle of 110-120 to the front surface of the plate, as well as reducing the rear back end 8 of the plate 2 and adjoining the detachment due to

The surface of the housing 1 to it is inclined to the front surface 3 of the plate 2 at an angle of 110-120 °.

The cutter works as follows.

In the process of cutting a rock or frozen ground from the side of the destroyed massif, the working edges of the tool contacting with it are affected by resistance forces. At the moment of cleavage of a large chip of frozen soil or rock, the resistance on the front surface of the cutter can decrease to zero, and in this case, if there is a wear area at the front end of the plate in the plane of the spa, maximum stress of detachment from the action of force arises: and P, Condition the effect of force P in the indicated direction is the inequality 9 ((i + h}, where 9 is the rake angle | fb is the angle of inclination of the wear area at the front end of the plate to the cutting plane; and c is the friction angle of the rock along the cutter. In the case of using the plate

tearing force due to a change in the angle of inclination of the support surface of the plate, the thickness of which decreases from the front end to

40 rearward, the strength of the paired connection of the plate with the housing increases. Reducing the thickness of the plate from the front end to the rear also allows to achieve its equal strength and economy.

jg hard metal to 25-30%.

Claims (1)

Invention Formula A cutter for mining and earth-moving gQ machines, comprising a body, a reinforced carbide plate with front and bearing surfaces, cutting edges, front and rear ends, characterized in that, with R., the target. Because of durability and a decrease in the consumption of cemented carbide, the front surface of the carbide plate is angled to the supporting surface and adjacent to it variable cross section force P decreases j as & at . The latter indicates that when making a carbide plate with variable width, with a ratio between the thicknesses on the side of the rear a and the front and the ends, within 0.5-0.7, the component of the force on the front end of the plate R: decreases that leads to a corresponding decrease in the stresses of separation in the joint and increase the strength of the cutter. In addition, when the ratio between the thickness of the 1 plates from the rear th aj and the front and ends within 0.5-0.7, the normal stresses from bending 6 on the front surface of the plate are distributed evenly along its entire length E, This thickness-thickness ratio makes it possible to create an equal-strength plate along the length of the weld seam (Fig .3), whereas, with the ratio a. / A, 1, the maximum tensile stresses 6 are observed at a certain distance 2 from the front end. plate (Fig, 4), and with respect to O ,, 5. the stress extremum is displaced to the rear end of the plate (Fig. 5), By making the back end of the plate and the adjacent part of the body at an angle of 110-120 to the front surface of the plate, as well as reducing the opening force due to a change in the angle of inclination of the supporting surface of the plate, the thickness of which decreases from the front end to back, the strength of the paired connection of the plate with the housing increases. Reducing the thickness of the plate from the front end to the rear also allows to achieve its equal strength and economy. hard alloy to 25-30%. Invention Formula A cutter for mining and earth-moving machines, comprising a body, reinforced with a carbide plate with front and bearing surfaces, cutting edges, front and rear ends, characterized in that, with a view. To ensure durability and reduce the consumption of cemented carbide, the front surface of the carbide plate is angled to the bearing surface and the body surface adjacent to it, the plate thickness from the rear end of the plate coch pressing 0.5-0.7 plate thickness from the front end and the back five the end of the plate and the adjacent surface of the housing are inclined to the front surface of the plate at an angle of 110-120.  a2 at  one fig, b . 5