Guide adapter

Abstract

A guide adapter for guiding a drill bit during percussion drilling is arranged between the drill bit and an elongated drill string extending along an axis. The guide adapter includes a sleeve shaped adapter body including a forward end with a first coupling arranged for connecting the guide adapter to the drill bit, and a rear end with a second coupling arranged for connecting the guide adapter to the drill string. A plurality of guiding elements extend substantially radially in relation to the axis from the adapter body. The guiding elements extend along 60% or less of the adapter body length and are arranged in the rear end. The guiding elements in the rear end have an extension in the radial direction substantially equal to a first radius of the drill bit and curved, straight or stepwise reduced radial extension towards the forward end.

Description

FIELD OF THE INVENTION[0001]The present invention generally relates to a guide adapter for guiding a drill bit during percussion drilling, and a drill arrangement comprising said guide adapter.TECHNICAL BACKGROUND[0002]Within the constructional work sector and the mining industry percussion drilling, such as top hammer drilling, is an established method for drilling vertical bore holes with a drill bit arranged in the forward end of an elongated drill string or cable. During drilling, a hammering impact from a hydraulically driven piston is acting on the drill string to exert the required force to break the rock and generate the bore hole.[0003]The length of the drill string is, during the drilling, increased by adding further drill string rods as the depth of the bore hole increases. When the depth of the bore hole increases also the risk for deviation from the intended straight direction of the bore hole increases. The problem with deviation could be reduced by adding a guide adap...

AI Technical Summary

Benefits of technology

The invention is a guide adapter for drilling that has special guide elements at the end. These elements are designed to guide the drill bit and reduce the weight of the guide adapter, which improves drilling performance. The guide elements also reduce friction between them and the bore hole, which further improves drilling performance. The guide adapter is used in a drill arrangement for percussion drilling, along with a drill string and drill bit. This arrangement helps to prevent deviation from the desired direction and ensures a smooth drilling process.

Problems solved by technology

When the depth of the bore hole increases also the risk for deviation from the intended straight direction of the bore hole increases.

The rear end surfaces are exposed to wear since the material removed from the rock to form the bore hole remain within the bore hole and due to gravitation tend to land on the rear end surfaces of the guiding elements.

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