SU1668610A1 - Crown bit - Google Patents

Abstract

The invention relates to a rock-breaking tool, namely to drill bits with coring. The aim of the invention is to increase the efficiency of the drill bit, mainly over fractured rocks by reducing self-core bits. This is achieved by the fact that the crown is provided with an annular rubber sleeve 6, having the form of an annular segment with a convex inner and outer conical surface 7, which is the chord of the segment. The sleeve 6 is fixed in the conical groove 5 of the housing above the coreplate and has an internal diameter D _in larger than the internal diameter D _{to the} crown. During drilling, core pieces fall into the gap between the core and the crown body 1, are retained by the rubber bushing and subjected to additional grinding, and then removed through the annular gap between the rubber bushing 6 and the core, which reduces the likelihood of core core self-stitching. 1 hp ff, 1 ill.

Description

The invention relates to a rock demolishing tool, namely, drill bits with coring.

The purpose of the invention is to increase the efficiency of the crown while drilling over fractured rocks by reducing core self-shrinks.

The drawing shows a General view of the crown in longitudinal section.

The drill crown includes a steel case 1 connected to a diamond-containing matrix, divided into sectors 2 by washing slots 3, Case 1 is made on the inner surface with conical bores 4 and 5, the bottom of which is intended for a core rotator (not shown), and the top is for a rubber annular sleeve 6, fixed against axial movement, for example with glue. The sleeve 6 has a cross-sectional shape of a circular segment, the chord 7 of which is forming the outer conical surface, the counter-conical surface 5 of the housing 1. At the same time, the inner diameter da of the sleeve 6 is larger than the inner diameter d of the crown (in terms of carbide weapons on the core-calibrating surface of the matrix - in diamond crowns).

The crown works as follows. The assembled drill bit, which includes a drill bit connected to the core pipe by means of a thread (not indicated by a position) on the housing 1, is lowered to the bottom of the well. In the tapered groove 4 corps 1 crown

about

Pre-insert the core ring (not shown). Through the drill string, axial load, torque and flushing fluid are transmitted from the machine to the crown, under the influence of which the crown destroys the bottom, calibrates the well and core. The drilled core passes freely into the core pipe through the crown cavity, mine core bore B conical bore 4, and rubber bushing 6 in conical bore 5 of housing 1. As the core length increases, its stability is lost, especially when drilling over fractured rocks with small diameters (46 and 59 mm), and the core is crushed into pieces. Small pieces of the core, as well as crushed fragments, fall into the gap between the core and the core tube, reach the rubber sleeve 6 and tend to wedge between the sleeve b and the core. However, since the rubbing strength of a rock piece is much less than that of a core, and the rubber sleeve b has a smooth bulge upward, the rock pieces are also squeezed up by elasticity of the rubber upward, where, meeting with other similar pieces, they destroy each other. Smaller pieces The core, as well as the further cut pieces, penetrate freely between the crown and core, and, without being jammed and not stuck in their wedging, are carried away by the washing liquid through the washing channels 3 between the sectors 2 of the matrix to the surface. In this way, the possibility of core jamming at the most dangerous in this respect place of the core shell, the conical groove of the crown, is reduced. The drilled core is captured by the core ring, located in the tapered groove 4 of the housing 1, and held during transport to the surface. If necessary

There is no rubber sleeve, it is either removed or not installed, and the core is held by the core ring in the groove 4 or with the backing material in tapered

grooves 4 and 5 of the housing 1.

The application of the described crown allows, without any significant expenditures of labor and means, to increase the shift productivity of drilling operations by increasing the length of trips, cruising speed, reducing the specific time for round-trip operations, improving the diagnostics and controllability of the drilling process, increasing the representativeness of core

material, and therefore the quality of geological work.

Claims (2)

1.Burov crown containing body with a conical bore under the corenator and working sectors reinforced by rock-destroying elements and separated by flushing grooves, characterized in that, in order to increase its efficiency in drilling over fractured rocks by reducing the core self-shrinkage, the crown is provided with a rubber ring bushing with a convex inner surface, the inner diameter of which larger than the internal diameter of the crown, while the sleeve is located above the conical bore under the core breaker and secured against axial movement. 2. The crown according to claim 1, characterized in that the rubber annular sleeve has in cross section, the shape of a circular segment, the chord of which is forming the outer conical surface, while the body is made with an additional conical bore on the inside surface mating outer surface of the sleeve. 7-. 6