| 摘要 |
The invention relates to a telescopic feed beam for a rock drill and to a method of measuring a travel length. The pressure surface of a piston (11b) in a feed cylinder (11) of the feed beam is twice as large as the pressure surface of a piston (6b) in a feed extension cylinder (6). Furthermore, the feed beam comprises a flow indicator (19) for measuring the volume flow rate of hydraulic fluid fed and/or discharged, and thereby the travel length.
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