SU1740610A1 - Crown bit - Google Patents

Abstract

Use: impact-rotational drilling of explosive wells. SUMMARY OF THE INVENTION: The crown comprises a body consisting of a head and a shank with a fastening assembly. On the head part there are feathers with carbide inserts, radial channels between the feathers and the central core-destructive recess. The purge channel goes into a core-destructive recess. Alternate annular protrusions are made on the surface of the recess. The center of the protrusions is offset from the axis of rotation of the crown. The magnitude of the displacement of the center of the annular protrusions is not greater than the magnitude of the step of the protrusions. The central axis of the protrusions is inclined relative to the axis of rotation of the crown. 2 hp f-ly, 2 ill.

Description

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The invention relates to mining, in particular to drill bits for percussion rotary drilling of explosive wells in rocks of different strengths.

A crown is known, containing a shank and a working head rigidly connected with it, the feathers of which are reinforced with carbide inserts of lamellar form and separated by radial channels and a core-forming central recess connected to an inclined through channel. On the end surface of the core-forming recess, a carbide probe is fixed, and the plane of the end face is made parallel to the cutting edges of the plates.

The disadvantage of this crown is a low drilling rate due to the inefficiency of core punching with a pin, since not the entire area of the crown face surface simultaneously participates in the destruction of the core face during drilling, but cyclically in

several places and is point character.

Also known is a drill crown, comprising a housing with plates, divided in the center by a core-forming recess, in which a coupling sleeve with a tapered surface is located, on which a carbide plate and pin are fixed.

In addition, there is a well-known crown, in which the core-forming cavity is made in the form of a truncated cone, the base of which is opened by a purge hole, and the head part is reinforced with carbide plates.

These crowns are also characterized by a low drilling rate due to the destruction of not the entire core area at the same time. In addition, when drilling soft rocks with crowns without plates in the cavity, the rock is deformed and takes the form of a cavity, closes the outlet of the blow-through

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holes and the drilling process is stopped. To resume drilling, it is necessary to raise the chisel above the face and re-launch the percussion mechanism.

The purpose of the invention is to increase the rate of drilling of soft and intermittently stressed rocks by improving the efficiency of core destruction during operation.

The goal is achieved by the fact that in a drill bit containing a body consisting of a shank with a fixing unit in the impactor and a head part on which pens reinforced with carbide inserts and separated by radial channels are made, and a central core-shaped recess with blown exit to it the channel, on the surface of the core-forming cavity, alternating annular projections are made, the center of which is offset relative to the axis of rotation of the crown.

The central axis of the annular projections is inclined relative to the axis of rotation of the crown.

In addition, the amount of displacement of the center of the annular protrusions is not greater than the magnitude of the step of the protrusions.

FIG. 1 shows the crown of the proposed design, view from the side of the head; in fig. 2 is a section A-A in FIG. one.

The proposed crown contains a working head 1 and a shank 2 rigidly connected to it, while on the head 1 there are several feathers 3 reinforced with carbide inserts 4, as well as a core-forming cavity 5 connected to the radial channels 6 and 7. On the end surface of the cavity 5 annular protrusions 8 are made, separated by depressions 9 with pitch t, displaced relative to the rotation axis 10 by the value e. In the head 1 and the shank 2 a through purge channel 11 is made. The pitch and displacement amount are related by the ratio t e.

The crown works as follows.

The crown of the shank 2 is secured in the hammer. The crown is transferred

torque with simultaneous striking of the shank 1. Under the action of these shocks and torque, carbide plates A destroy the rock. The destroyed rock is removed from the head of the well by compressed air, which is fed through channel 11 into cavity 5 and further through radial channels 6 and 7 into the well. The destruction of the rock in the center of the well is carried out by protrusions 8, which, when rotated, constantly move in the radial plane and destroy the entire bottom area simultaneously. The plane of the implementation of the protrusions 8 and cavities 9 can be performed

flat or inclined, and also in the form of a sphere or concavity.

The use of the proposed crown allows to increase the drilling rate of wells due to the simultaneous destruction

the entire plane of the bottom hole in the core cavity by 20-30% compared with the known.

Claims (3)

1. A drill crown containing a body consisting of a shank with a fastening unit in the drummer and a head on which a feather is made, reinforced with carbide inserts and separated between the radial channels, the central core-destructive recess with the exit of the purge channel to it, characterized in that, in order to increase the drilling rate by improving the efficiency of core destruction, alternate annular projections are made on the surface of the core-destructing, the center of which is offset from the axis of rotation of the crown. 2. Crown pop. 1. characterized in that the central axis of the annular projections is inclined relative to the axis of rotation of the crown. 3. The crown according to claim 1, characterized by the fact that the magnitude of the displacement of the center of the annular protrusions relative to the axis of rotation of the crown is not greater than the magnitude of the pitch of the protrusions, figure 1 FIG. 2