RU2558097C1 - Four-stage three-bladed rotary bit for rotary blasthole drilling - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: four-stage three-bladed rotary bit for rotary blasthole drilling includes a cutting stage, a drill cuttings excavation stage, a locking stage for fastening on a drilling rod. The cutter is also fitted with a clamping stage located between the excavation stage and the locking stage providing the strength joint of the cutter with the rod, and heights of all four stages along the geometrical axis of rotation of the cutter are designed in the ratios 2/10:3/10:2/10:3/10 of the total height of the cutter with the tolerance per each stage ±0.5/10. The cutting stage has hard-alloy plates designed as heptahedrons, two sides of which are designed mutually perpendicular and used for their fastening by means of solder on a congruent body of the cutter, two frontal sides, forming together an obtuse angle, are intended for direct contact with drilled rock, and three other sides form with two frontal ones cutting edges with various angles of cutting. The flange of the drill cutting excavation stage screw is designed by height with the changing step and with the decreasing radius from the cutting step to the clamping stage. The clamping stage intended for fastening on the drilling rod is designed with six pairwise-parallel flat sides the distances between which are set according to the ready-to-operate standard sizes. The locking stage is designed as a threaded connection with an internal hole which can be designed cylindrical or according to the parabolic or conic law with diameter decrease towards the clamping stage.

EFFECT: improvement of working capacity and creation of design of a cutter capable to blasthole drilling in massifs of rocks.

4 cl, 9 dwg

Description

The present invention relates to mining, and more particularly to cutters designed for drilling holes in rock masses.

From the existing level of technology, a cutter for rotary drilling of holes is known [1, p. 58, Fig. 3.22, cutter RP-7], which is a two-feather cutter that includes two steps: a cutting step and a locking step. At the first stage there are symmetrically carbide inserts relative to the axis of the cutter. The second stage is made in the form of a wedge section with a hole for fixing the cutter on the rod.

The disadvantage of such a cutter is the impossibility of its use when drilling fractured rocks, when the cutter blades can fall into the longitudinal cracks of the rock and jam in them. Such jamming can lead to the cessation of the drilling process and to breakage of the cutter blades.

Closest to the claimed technical solution is a three-feather cutter for drilling holes (RF Patent for Utility Model No. 53702 dated December 22, 2005), which includes three steps: a cutting step, an excavation step, and a locking step. At the first stage there are three carbide inserts that are installed relative to each other at the same distance around the circumference. At the second stage, the blades of carbide inserts cutting the walls of the borehole form the flanges of the three-auger screw with a pitch of at least three lengths of the cutter body. The working blades of the plates are made in the plan in the form of wedges directed by the tips in the direction of rotation of the cutter.

The disadvantages of this technical solution is the cylindrical screw of the housing. This form leads to friction of the body of the cutter on the wall of the hole. As a result, the body of the cutter wears out and its resource decreases. And also there is no step that provides for the installation and removal of the cutter from the rod.

The task to which the invention is directed is to eliminate the shortcomings, increase the working capacity and create a cutter design capable of drilling holes in rock masses.

The problem is solved due to the fact that the inventive four-stage three-blade drill cutter for rotary drilling of holes, including a cutting step, a stage of excavation of drill cuttings, a locking step for mounting on a drill rod, characterized in that it is equipped with an additional clamping step located between the step excavation and castle step, providing power connection of the cutter with the rod, and the heights of each of the four steps along the geometric axis of rotation of the cutter are made in Wearing 2/10: 3/10: 2/10: 3/10 of the total height of the cutter, with a tolerance for each stage ± 0,5 / 10. Carbide inserts having the shape of a heptahedron are located on the cutting step, two of the faces of which are mutually perpendicular and serve to fix them by means of solder on the congruent body of the cutter, two frontal faces, forming an obtuse angle between them, are designed for direct contact with drill rock, and the three remaining faces form with two front cutting edges with different cutting angles. The ridges of the screw of the excavation step of the cut rock are made in height with a varying pitch and with a decreasing radius from the cutting step to the clamping step. The clamping step, designed for mounting on a drill rod, is made with six pairwise parallel flat faces, the distances between which are set in accordance with standard turnkey dimensions. The locking step is made in the form of a threaded connection with an internal cylindrical hole.

An edge formed by one frontal face and a face serving to fix the carbide plate can be made in the form of a platform.

The excavation step can be performed with flushing holes in the recesses of the screw directly under the carbide plates.

The clamping step can be made with different sizes between pairwise parallel faces, which allows the use of various standard keys for power connection of the cutter with the rod.

The inner hole of the cutter, located in the castle step, can be made according to a parabolic or conical law with a decrease in diameter to the clamping step, which provides a more uniform load distribution along the threads.

The technical result provided by the given set of features is to create a design with improved performance and increased tool life, as well as with the ability to quickly replace.

The design is illustrated by drawings, which depict:

Figure 1 - Four-stage three-blade drill for rotary drilling of holes.

Figure 2 - Hexagon carbide plate.

Figure 3 - stage of excavation.

Figure 4 - Cross section of the clamping stage with the execution of one key.

Figure 5 - Section of the clamping stage with the execution of two keys.

Figure 6 - Cross section of the clamping stage with the execution of three keys.

Figure 7 - Castle step with an internal cylindrical flushing hole.

On Fig - Castle step with an internal parabolic flushing hole.

In Fig.9 - Castle step with an internal conical flushing hole.

Four-stage three-blade drill bit for rotary drilling of holes is made as follows.

The cutter consists of four steps: the cutting step, the excavation step, the clamping step and the locking step (Fig. 1). The steps along the length are made in the ratio: h ₁ : h ₂ : h ₃ : h ₄ = 2/10: 3/10: 2/10: 3/10, and the tolerance for each step is ± 0.5 / 10.

At the first step, the cutting step, three seven-sided carbide inserts are installed relative to each other at the same circumference. The seven-sided plate is fixed with two mutually perpendicular faces 4 and 5 by means of solder on the congruent body of the cutter (figure 2). The frontal faces 6 and 7 form an obtuse angle between them. They are designed for direct contact with drill rock. Facets 8, 9, 10 with two frontal 6 and 7 form cutting edges with different cutting angles. The rib 11 formed by one frontal face 7 and face 4, which serves to fix the carbide plate, can be made in the form of a platform.

At the second stage, excavation stage, carbide plate 1, the flanges 3 of the three-way screw are formed. The screw ribs are performed in height with a varying pitch t and with a decreasing radius r from the cutting step to the clamping step, as well as with a variable helical angle α of lifting (Fig. 3). Flushing holes 2 in the recesses of the screw can be made directly under the soldered carbide plates 1.

The third step, the clamping step, designed for mounting the cutter on the drill rod, is made with six pairwise parallel flat faces in such a way that the distance between the parallel faces is changed in accordance with standard turnkey dimensions. Three different designs are possible. With one turnkey size s ₁ , when the distances between pairwise parallel faces are equal (Fig. 4). With two sizes s ₁ and s ₂ , when the distances between two pairs of parallel faces are equal (figure 5). And three s ₁ , s ₂ and s ₃ , when all the distances between pairwise parallel faces are different (Fig.6).

The fourth step, the locking step, is made in the form of a threaded connection 12 and an inner cylindrical hole 13 (7). For a uniform load distribution on the threads, the inner hole 14 can be made of variable radius according to a parabolic law with a decrease in diameter to the clamping step (Fig. 8). To simplify the manufacture, a conical design of the hole 15 is possible (Fig. 9).

The cutter works as follows. With a locking step, the cutter is connected to the bar with a thread. The cutter is set to rotate and at the same time axial movement to the face. The cutting step cuts the rock with three carbide inserts at the bottom, moving the wedges of the wedges of the plates in the direction of rotation in plan. So that the destroyed material does not prevent the cutter from moving further towards rotation, it moves along the auger located on the step. The conical shape of the auger prevents friction of the body against the hole, which reduces wear on the cutter. The clamping step is hexagonal, with a variable size allows you to remove the cutter, if necessary, with an ordinary wrench, and the sizes of suitable wrenches can be different.

A four-stage three-blade drill bit for rotary drilling of holes can be used for drilling holes in rock masses for fixing the roof of coal mines.

Information sources

1. Krapivin M.G. Mountain tools. Ed. "Nedra", Moscow, 1979, p.263.

2. Alimov O.D., Dvornikov L.T. Drilling Machines Ed. "Mechanical Engineering", Moscow, 1976, p.295.

Claims (4)

1. Four-stage three-blade drill cutter for rotary drilling of holes, including a cutting step, a stage of excavation of drill cuttings, a locking step for mounting on a drill rod, characterized in that it is equipped with an additional clamping step located between the excavation step and the locking step, providing power the connection of the cutter with the rod, and the heights of each of the four steps along the geometric axis of rotation of the cutter are made in the ratios 2/10: 3/10: 2/10: 3/10 of the total height of the cutter with a tolerance of azhduyu stage ± 0,5 / 10; carbide inserts having the shape of a heptahedron are located on the cutting step, two of the faces of which are mutually perpendicular and serve to fix them with solder on the congruent body of the cutter, two front faces forming an obtuse angle between them are intended for direct contact with the drill rock, and the three remaining faces form with two front cutting edges with different cutting angles; the flange of the screw of the excavation step of the cut rock is made in height with a varying pitch and with a decreasing radius from the cutting step to the clamping step; the clamping step, designed for mounting on a drill rod, is made with six pairwise parallel flat faces, the distances between which are set in accordance with the standard turnkey dimensions; the locking step is made in the form of a threaded connection with an internal hole, which can be made cylindrical or according to a parabolic or conical law with a decrease in diameter to the clamping step. 2. The four-stage three-blade drill bit for rotary drilling of holes according to claim 1, characterized in that the rib formed by one front face and a face serving to fix the carbide plate can be made in the form of a platform. 3. The four-stage three-blade drill for rotary drilling of holes according to claim 1, characterized in that the excavation step can be performed with flushing holes in the recesses of the screw directly under the carbide inserts. 4. The four-stage three-blade drill for rotary drilling of holes according to claim 1, characterized in that the clamping stage can be made with different sizes between pairwise parallel faces, which allows the use of various standard keys for power connection of the cutter with the rod.

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