US 12,264,583 B2
Hydraulic system with safety mode, rock drilling rig and method
Juho Rantanen, Tampere (FI); Pertti Parkkinen, Tampere (FI); Samuli Verho, Tampere (FI); Harri Vatanen, Tampere (FI); and Teemu Hongell, Tampere (FI)
Assigned to Sandvik Mining and Construction Oy, Tampere (FI)
Appl. No. 18/694,639
Filed by SANDVIK MINING AND CONSTRUCTION OY, Tampere (FI)
PCT Filed Sep. 20, 2022, PCT No. PCT/EP2022/076002
§ 371(c)(1), (2) Date Mar. 22, 2024,
PCT Pub. No. WO2023/046647, PCT Pub. Date Mar. 30, 2023.
Claims priority of application No. 21198713 (EP), filed on Sep. 24, 2021.
Prior Publication US 2024/0392628 A1, Nov. 28, 2024
Int. Cl. E21B 7/02 (2006.01); E21B 44/02 (2006.01)
CPC E21B 7/022 (2013.01) [E21B 7/025 (2013.01); E21B 44/02 (2013.01)] 5 Claims
OG exemplary drawing
 
5. A method for limiting output performance of a hydraulic drilling actuator temporarily under execution of a safety function feature of a hydraulic system, the method comprising:
limiting hydraulic features of an input hydraulic fluid directed to the hydraulic drilling actuator connected to a hydraulic circuit of the hydraulic system;
limiting an output performance of the hydraulic drilling actuator by limiting produced hydraulic fluid flow in the hydraulic circuit of the hydraulic drilling actuator, whereby a restricted magnitude of the fluid flow is produced at a hydraulic pump of the hydraulic circuit for a duration of a restricted operation mode of the safety function feature;
driving the hydraulic pump by an electric motor; and
controlling a rotation speed of the electric motor and the hydraulic pump to produce the a restricted magnitude of flow of the hydraulic fluid, wherein the electric motor is a speed controlled electric motor controlled by a variable frequency drive serving as the electrical motor control device, the variable frequency drive including an integrated safety function based on a hard wired safety circuit.