RU2298636C1 - Drill head for short hole drilling in frozen ground - Google Patents

Abstract

FIELD: rock-cutting tools, particularly drilling bits.

SUBSTANCE: drill head comprises two-wing body 2, blades 2 with hard-alloy cutting plates 5 installed on blade bodies, stem 1 and starting borer 6 with guiding member 7. Working surfaces of cutting plates are sharpened. Two blade rows 3, 4 are arranged on the two-wing body so that each blade row is connected to each body wing. Wings are located so that 180° angle is defined in-between. Pitch between blades 3 of the first row is equal to that of the second row. Blades 4 of the second row are shifted with respect to blades 3 of the first row for value equal to 1/2 of blade pitch. Blade 4 diameter is twice as large as that of blade 3. Cutting edges of blades 3 and 4 are inclined towards head rotation direction. Working surfaces of hard-alloy cutting plates 5 are inclined towards bodies at angle of 20° to provide forward stress concentration in head rotation direction.

EFFECT: conversion of hole drilling operation into high contact stress creation method along with following crack formation accompanied by large particle chipping, collapse, crumbling and generation of dispersed mass, which flows around steel blade bodies.

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Description

The invention relates to a rock cutting tool.

A device for producing a well in the soil by the rolling method is known (A. S. 497401 USSR, IPC Е21В 11/02, publ. 30.12.75, bull. No. 48). The device consists of a spindle with an eccentric, freely sitting conical tip; wedges and counter-wedges are fixed to the spindle. In the place of bushings, the spindle has a square (or round) cross-sectional shape. On the bushings they sit with the possibility of free rotation of the rollers of conical or cylindrical shape.

The disadvantage of this device is low productivity and high specific energy consumption.

A blade reversible bit is known (A.S. 1040112, IPC 3 Е21В 11/00, publ. 07.09.83, bull. No. 33), including a housing with grooves in which the blades are placed, the grooves are made in the form of cylindrical holes, each blade fixed in the groove with the possibility of rotation by a predetermined angle by means of two segments located on the sides of the part of the blade entering the groove and fastened together by screws.

The closest technical solution known is a blade chisel, consisting of a housing, interchangeable blades, a pilot tip and rotating cutters / RU 2243347 C1, IPC 7 Е21В 10/42, publ. 2004.12.27 /. The axis of the rotating cutter lies on a plane parallel to the plane of the blade, and is directed at an angle to the axis of the blade, passing through a point lying on a circle bounded by the diameter of the borehole from the side of its bottom.

The disadvantages of these blade bits are low productivity, high specific energy consumption, quick dullness and wear of the cutter, especially when drilling hard and frozen soils.

The task to which the claimed technical solution is directed is to translate the process of drilling a well in frozen soils to the method of creating high contact stresses with the subsequent formation of cracks, accompanied by large cleavage, crushing, crumbling and the formation of a dispersed mass flowing around the steel bodies of the cutters.

The technical result is an increase in productivity, a decrease in energy intensity and an increase in the service life of incisors in hard and frozen soils.

The specified technical result is achieved by the fact that the head for drilling shallow wells in frozen soils, containing a two-bladed body, cutters, on the bodies of which are mounted carbide cutting inserts, the working surface of which is pointed, a shank, a bore with a guide element, the feature is that on a two-bladed the body there are two rows of incisors, one row on each blade, while the blades are located at an angle of 180 °, and the pitch between the cutters of the first row is equal to the pitch between the cut the second row with a shift of 1/2 step, with the diameter of each tool of the second row more than the diameter of the tool of the first row 2 times, the cutters are installed with an inclination - cutting edge forward in the direction of rotation, and the working surfaces of carbide cutting inserts are inclined to the bodies under angle of 20 ° - stress concentrators forward in the direction of rotation during drilling.

The invention is illustrated by drawings, where figure 1 shows the head for drilling shallow wells in frozen soils; figure 2 is a view along arrow a in figure 1; figure 3 presents a view of the cutter of the first row; figure 4 presents the inclination of the cutter and the cutting direction (arrow V); figure 5 is a view along arrow a in figure 4; figure 6 presents the profiles of the chip 1-1 cutters of the first row and 2-2 - cutters of the second row; figure 7 presents a diagram of the relative alignment of the incisors of the 1st and 2nd row.

The head for drilling shallow wells in frozen soils is installed on the lower end of the auger of the MBSh-425 drilling machine (auger drilling machine) by means of a shank 1 and includes a two-bladed body 2, consisting of two rows of cutters on each blade in one row. Cutters have a cylindrical shape in each row, but different sizes for each row (in length and diameter). In this case, the incisors 3 of the first row pass between the passages of the incisors 4 of the second row, therefore, the installation step of the incisors of the first row is taken equal to the installation step of the incisors of the second row with a 1/2 step shift. Each cutter 3 and 4 consists of a steel body (figure 3) with a carbide cutting plate 5 made of hard material mounted at the end and sharpened at an angle α = 60 °. On the two-bladed body 2, the cutters are installed with a slope - the cutting edge forward in the direction of rotation - arrow V (see figure 2, 3 and 4). The diameter of each incisor 4 of the second row is 2 times larger than the diameter of the incisor 3 of the first row. In the lower central part of the two-bladed body 2 there is a bore 6 with a guiding element 7. The blades are located at an angle of 180 °, the working surfaces of carbide cutting inserts at the cutters, which perform the function of stress concentrators in the process of contact with frozen soil, are pointed. The carbide cutting insert 5 is mounted on the cutter so that its working surface is inclined at an angle of 20 ° by stress concentrators forward in the direction of rotation during drilling.

The head for drilling shallow wells in frozen soils works as follows.

In the initial position, the two-bladed body 2, mounted through the shank 1 at the lower end of the auger of the drilling machine, is led by a bore 6 with a guiding element 7 and cutters 3 and 4 with carbide cutting inserts 5 installed in two rows, to the well drilling site, lowered to the ground surface . Turns on arrow V (FIG. 2) and axial force supply to the head for drilling the well. The drilling process begins when the incisors 4 of the second row are deepened into the soil (Fig. 7) and continues with the incisors 3 of the first row by the method of cracking followed by large chipping, crushing, crumbling and the formation of a dispersed mass flowing around the steel bodies of the incisors 3 and 4.

In this case, the chipping of the second row of incisors 4 occurs entirely, and the chipping of the first row of incisors 3 occurs along the tops of the ridges remaining after the passage of the second row of incisors, due to the fact that the step between the first row of incisors 3 is taken to be equal to the step of the second row of incisors 4 with a shift by 1/2 step (see Fig.6 and 7). In the process of rotational movement, chipping of each subsequent penetration occurs along the tops of the ridges remaining after the chips of the previous penetration.

Thus, the drilling process is carried out by the method of cracking with the subsequent occurrence of a cleavage with the beginning at the points of contact of the cutters as stress concentrators and due to the forces directed fan-shaped from the points of force contact of the stress concentrators with frozen ground. As a result, a fan-like cleavage of soil is made from the plane of horizontally directed sliding to the vertical direction to it. All this reduces the effort required for drilling shallow wells, increases the drilling speed and productivity of the drilling process, reduces the energy consumption of the process of drilling shallow wells and increases the service life of the working parts of the tip for drilling shallow wells.

The use of the head for drilling shallow wells in frozen soils allows you to: reduce the effort required for drilling shallow wells, and increases the speed of drilling and productivity of the drilling process; reduce the energy intensity of the process of drilling shallow wells; increase the life of the head for drilling shallow wells.

Claims (1)

A head for drilling shallow wells in frozen soils, containing a two-bladed body, cutters, on the bodies of which carbide cutting inserts are installed, the working surface of which is pointed, a shank, a bump with a guide element, characterized in that on the two-bladed body there are two rows of cutters in one row on each blade, while the blades are located at an angle of 180 °, and the step between the incisors of the first row is equal to the step between the incisors of the second row with a shift of 1/2 step, and the diameter of each the cutters of the second row are 2 times larger than the diameter of the cutters of the first row, the cutters are installed with an inclination — the cutting edge is forward in the direction of rotation, and the working surfaces of carbide cutting inserts are inclined to the bodies at an angle of 20 ° —concentrators of stresses forward in the direction of rotation when drilling.

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