Impact device with a rotable control valve
AssigneeSandvik Mining and Construction Oy
InventorsMarkku Keskiniva, Jorma Maki, Mauri Esko, Erkki Ahola
Life of this patent
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Abstract
The invention relates to an impact device comprising a frame to which a tool is connectible, and between the frame and the tool a stress element (3) supported to the frame of the impact device, and a hydraulic fluid space (6) and means for leading pressurized hydraulic fluid into and out of the hydraulic fluid space (6), respectively. The impact device comprises a rotatingly installed control valve (5) having control channels (5b) for leading the hydraulic fluid intermittently from the hydraulic fluid space (6) to the return channel.
Claims26
An impact device for generating a stress pulse in a tool (4), the impact device comprising a frame (2) to which the tool (4) is connectible, and between the frame (2) and the tool (4) a transmission member, such as a transmission piston (7), the tool (4) being in contact with the tool-side (4) end of the transmission member either directly or indirectly at least part of the time during the generation of the stress pulse, means for generating a force between the frame (2) and the transmission member such that the force tends to push the transmission member towards the tool (4), and a first hydraulic fluid space (6) on the tool-side (4) relative to the transmission member (7), whereby the transmission member (7) comprises a first pressure surface located on the side of the first hydraulic fluid space (6) towards the tool (4), means for leading pressurized hydraulic fluid into said first hydraulic fluid space (6) and for enabling sudden flow of the hydraulic fluid out of said first hydraulic fluid space (6) such that said force between the frame (2) and the transmission member causes, either directly or indirectly via the transmission member (7) and when the transmission member is in contact with the tool (4), a force compressing the tool (4) in its longitudinal direction and, due to the effect thereof, a stress pulse in the tool in its axial direction, and a hydraulic fluid channel (9) for feeding pressurized hydraulic fluid into the impact device, and a discharge channel (10) for leading the hydraulic fluid out of the impact device, character ized in that the means for leading hydraulic fluid out of the first hydraulic fluid space (6) comprise a rotatingly installed control valve (5) having control channels/openings (5b) for leading the hydraulic fluid intermittently from the first hydraulic fluid space (6) to the discharge channel (10), and that the control valve (5) has several parallel control channels/openings (5b) that substantially simultaneously open a connection between the first hydraulic fluid space (6) and the hydraulic fluid discharge channel (10), respectively.
An impact device as claimed in any one of the preceding claims, characterized in that the control valve (5) is installed to continuously rotate in the same direction.
An impact device as claimed in any one of the preceding claims, characterized in that the rotating control valve (5) is rotated with a hydraulic medium-driven, preferably a hydraulic fluid-driven motor.
An impact device as claimed in any one of the preceding claims, characterized in that it comprises at least one separate auxiliary valve (15) coupled to be controlled by the rotating control valve (5) such that when hydraulic fluid is fed into the first hydraulic fluid space (6), each auxiliary valve (15) closes the connection from the hydraulic fluid space (6) to the return channel (10) and, correspondingly, when the hydraulic fluid is allowed to flow away from the first hydraulic fluid space (6), opens the connection from the hydraulic fluid space to the return channel (10).
An impact device as claimed in any one of the preceding claims, characterized in that the rotating control valve (5) comprises a sleeve-like part in which at least part of the control channels/openings are formed.
An impact device as claimed in any one of the preceding claims, characterized in that the rotating control valve (5) comprises a flange-like part in which at least part of the control channels/openings are formed.
An impact device as claimed in any one of the preceding claims, characterized in that seals (20) adjustable with hydraulic medium are arranged between the control valve (5) and the frame (2) of the impact device.
An impact device as claimed in any one the preceding claims, characterized in that hydraulic fluid is fed from the hydraulic fluid pump (8) to the rotating control valve (5) and, correspondingly, from the control valve (5) through the discharge channel to a hydraulic fluid tank (11) over part of the length of the feed channel and discharge channel, respectively, along several parallel feed channels and discharge channels, respectively, and that the number of channels (5a) in the rotating control valve (5) and the number of parallel feed channels (9a) and discharge channels, respectively, leading to the control valve (5) are multiplied in accordance with the same integer.
A control valve for controlling the work cycle of a hydraulic fluid-driven impact device (1), a feed channel (9) leading to the impact device (1) and, correspondingly, a discharge channel (10) for leading hydraulic fluid into and out of the impact device, the control valve (5) being intended to be installed rotatingly in a space in a frame of the impact device (1), at least one hydraulic fluid discharge channel leading to said space, the control valve (5) comprising at least one channel or opening for controlling the flow of hydraulic fluid, characterized in that the control valve (5) comprises a plurality of parallel channels or openings (5b), which, as the control calve (5) is rotating, alternately simultaneously open a connection from the impact device (1) to the discharge channel (10) and close the connection to the discharge channel (10), respectively.
Dependencies are inferred from the claim text.