# Improving the operational durability of tangential-rotary picks for rock cutting with central spraying and hydrodynamic rotation

## TL;DR

This paper introduces a new design for tangential-rotary picks used in rock cutting that improves their durability through central spraying and hydrodynamic rotation.

## Contribution

The paper proposes a novel design with central spraying and compressive stress induction to enhance pick durability.

## Key findings

- Central spraying and hydrodynamic rotation increase the service life of picks.
- FEM simulations confirm the effectiveness of the reinforcing sleeve in improving fatigue strength.
- Optimal tension nut torque for the reinforcing sleeve was determined.

## Abstract

This article presents a proposal for a new solution of tangential-rotary picks intended for mining, especially hard rocks with roadheaders. The design of these picks is characterized by many innovative solutions aimed at significantly increasing their service life. The method to achieve this goal is to provide effective central spraying of the ring tip picks, crown picks, or similar types of picks while using the spray water to cause the picks to rotate as they contact the rock being mined. An important element of the work is to conduct extensive simulation studies using FEM to determine the stress distribution in the pick shank subjected to external load from cutting. The new design of the tangential-rotary pick is equipped with a reinforcing sleeve, in which a state of compressive stress is induced. This enables a significant improvement in the fatigue strength of the pick shanks. The conducted FEM comparative tests confirm the accuracy of the adopted design assumptions. They also determine the beneficial value of the tension nut torque, which tightens the reinforcing sleeve located on the pick shank.