St. Petersburg Mining University (St. Petersburg, Russia):

Yungmeyster D. A., Professor, Doctor of Engineering Sciences, Yungmeyster_DA@pers.spmi.ru
Brichkin V. N., Head of Chair, Doctor of Engineering Sciences, Brichkin_VN@pers.spmi.ru
Isaev A. I., Associate Professor, Candidate of Engineering Sciences, Isaev_AI@pers.spmi.ru

The article discusses oversize reduction in the operation of crushers, in handling of frozen rocks on receiving hopper grizzly grates at metallurgical enterprises and processing plants, when crushing large metallurgical castings, and in a number of other applications. Within the framework of the problem, a hammer drill design is presented, enabling operation in the impact and impact-rotation modes, which significantly increases the scope of application of the presented oversize reduction device actuator. The design of the oversize reduction actuator is considered, including a double hammer drill installed on a handling unit chassis. The article presents the results of experimental studies to identify the main parameters of the proposed hammer actuator and describes the dependencies for the peak penetration value at different cutting edge angles for the rock being cut by establishing the dependence in the power form as a function of its energy and impact frequency. A formula is proposed for calculating the theoretical performance of the hammer drill, taking into account the impact frequency and the cutting edge angle of the rock-cutting tool. The article highlights that the use of pneumatic impactors with increased impact system efficiency in crushers enables the application of compressed air jets for cleaning the receiving openings, grates and conveyor belts, which expands the applications for this design.

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