RU2566151C1 - Drill bit and method of securing of its inserts - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: invention relates to rock destructing tools provided with hard-alloy inserts. Drill bit comprises the body with bores to receive the hard-alloy inserts with cylindrical stems. Sleeves of resilient material shaped to barrel with bottom hole are arranged between the bore walls and insert outer surface. Note here that inserts have the stepped stem. Smaller diameter stage height is not smaller than the depth of the barrel bottom depth. Diameter of this stage complies with the barrel bottom opening diameter. The end of lower step of every stem can have the spherical ledge. Bottom hole can have the mating recess. Claimed method consists in fitting the drill bit cylindrical stems in the drill bit body holes. Note here that resilient sleeves are fitted between hole walls and outer surface of insert stems and stretched in lengthwise direction before fitting them in place.

EFFECT: simplified fabrication and attachment.

3 cl, 1 dwg

Description

The invention relates to the field of mining, and in particular to a rock cutting tool with carbide weapons.

A drill bit is known that contains a body with holes in which carbide inserts are fixed (see ed. St. USSR 446622, class E21B 10/16, 1972).

In this bit, the method of fixing the inserts in the holes of the bit body is carried out by pressing them

The disadvantage of this bit is the low efficiency due to the rapid failure of its weapons, and the disadvantage of the applied method of attaching the inserts is the complexity of pressing the inserts.

The closest to the proposed technical essence and the achieved result is a drill bit containing a housing with holes in which carbide inserts with cylindrical shanks are pressed in (see US patent No. 3603414, CL 175-374, 1971).

In this bit, thanks to the use of inserts with a multi-faceted shank, high reliability of their fastening in the holes of the housing is ensured. However, this bit is also not without serious drawbacks, the main of which is the complexity of the technology for the manufacture of insert shanks, which inevitably leads to higher cost of bits.

The method of attaching inserts in this bit includes pressing the shanks with a faceted outer surface in the holes of the bit body.

In view of the technical result of the invention, it is a simplification of the manufacturing technology of the bit and the method of fastening the inserts in the openings of the body and, as a result, a reduction in the cost of the bit.

The specified technical result to simplify the manufacturing technology of the bit is achieved by the fact that in the drill bit containing a housing with holes in which carbide inserts with cylindrical shanks are fixed, according to the invention, bushings made of elastic material made in the form of a cup are placed between the walls of the holes and the outer surface of the insert shanks with an opening at the bottom, while the inserts are made with a stepped shank, the height of the step of a smaller diameter of which is not less than the thickness of the bottom of the glass, and the diameter This step corresponds to the diameter of the holes on the bottom of the glass.

The achievement of the specified technical result is also facilitated by the fact that the end face of the lower stage of each shank is made with a spherical protrusion, and the bottom of the hole for inserts in the body with a reciprocal cavity.

The specified technical result to simplify the method of attaching the bit inserts is achieved by the fact that in the proposed method, which includes pressing the faceted shanks of the inserts in the holes of the bit body, according to the invention, bushings of elastic material are placed between the walls of the holes and the outer surface of the shanks of the inserts, which are stretched in the longitudinal direction before pressing direction.

The invention is illustrated in the drawing, which shows a fragment of the drill bit on an enlarged scale.

The drill bit contains a housing 1 with holes 2, in which carbide inserts 4 with cylindrical shanks 5 are fixed by bushings 3 of elastic material. The bushings 3 are placed between the outer surfaces of the shanks 5 and the side walls of the holes 2. The sleeve 3 is made in the form of a glass with a hole 6 at the bottom, and inserts 4 are made with a stepped shank, the height of the step 7 of a smaller diameter not less than the height of the bottom of the glass, and the diameter of this step 7 corresponds to the diameter of the hole 6 at the bottom of the glass. An embodiment of the end face of the lower stage of each shank with a spherical protrusion 8 is provided, and the bottom of the hole 2 for the insert 4 in the housing 1 has a mating cavity 9. The shank 5 with a stepped surface provides reliable fixation of the elastic sleeve 3 on the insert 4, which is necessary when attaching the insert 4 in the hole 2 of the housing 1. In this case, the choice of the thickness of the bottom of the glass (sleeve) 3 and the diameter of the hole 6 is due to the fact that the axial shock load transmitted from the housing 1 to the inserts 4 through the step 7 of the shank 5 of small diameter pa The presence of spherical protrusions 8 and counter cavities 9 increases the contact surface of the housing 1 with the ends of the shanks 5 and thereby reduces the specific load on the partition between the support of the bit and the ends of the shanks of the inserts 4 when using the present invention for reinforcing roller cone bits. In roller cone bits this is especially important given the fact that the thickness of this partition is very small.

The method of attaching the inserts in the bit includes the operation of pressing their cylindrical shanks 5 in the holes of the bit body and placing between the walls of the holes 2 and the outer surface of the shanks of the inserts 4 of the sleeve 3 of elastic material, which are stretched in the longitudinal direction before pressing the shanks 5 into the holes 2 of the body 1 of the bit . In this case, the outer diameter of the sleeve 3 should be no more than the diameter of the hole 2. Given that the manufacturing technology of the bushings 3 is much simpler in comparison with the technology of manufacturing polyhedral shanks, as well as the technology for assembling the weapons of the proposed bit in comparison with the prototype, a significant reduction in the cost of the proposed chisels.

The proposed invention can be used both in cone bits and in bits for percussion drilling, mainly in bits of large diameter. Using it will significantly reduce the cost of drilling, making up the bulk of all exploration work.

Claims (3)

1. A drill bit containing a housing with holes in which carbide inserts with cylindrical shanks are fixed, characterized in that between the walls of the holes and the outer surface of the shanks of the inserts are bushings made of elastic material made in the form of a glass with a hole at the bottom, the inserts being made with a stepped shank, the height of the step of a smaller diameter of which is not less than the thickness of the bottom of the glass, and the diameter of this stage corresponds to the diameter of the hole on the bottom of the glass. 2. The drill bit according to claim 1, characterized in that the end face of the lower stage of each liner is made with a spherical protrusion, and the bottom of the hole for inserts in the body with a reciprocal cavity. 3. A method of attaching drill bit inserts, including pressing their cylindrical shanks in the holes of the bit body, characterized in that bushings of elastic material are placed between the walls of the holes and the outer surface of the insert shanks, which are stretched in the longitudinal direction before pressing the shanks.

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