(19)
(11) EP 0 080 446 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
23.01.1985 Bulletin 1985/04

(43) Date of publication A2:
01.06.1983 Bulletin 1983/22

(21) Application number: 82850229

(22) Date of filing: 12.11.1982
(84) Designated Contracting States:
AT CH DE FR GB IT LI SE

(30) Priority: 20.11.1981 SE 8106907

(71) Applicant: Atlas Copco Aktiebolag
 ()

(72) Inventors:
  • Wijk, Axel Gunnar
     ()
  • Andersson, Kurt Holger
     ()

   


(54) Method of controlling an impact motor and an impact motor


(57) In a rock drill, the feed force is transmitted from the housing 11 of the rock drill to the drill stem or drill stem adapter 14 via a damping piston 17. The damping piston 17 rebounces by the reflected compressive shock waves and the rebounce is sensed and used to control a control pin 48 which adjusts the stroke length of the hammer piston 13 so that the reflected shock wave energy is minimized.






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