Lkab Wassara Ab

Martin Öhnström

Magnus Fridsell

Magnus Hörman

Fredrik Egerström

The invention relates to a rotary device () for a down-the-hole hammer (), which rotary device is accommodated in a rotation motor housing () and mounted behind a drill housing () for transferring a torque to a drill bit () and a pressurized drive fluid () to a striking mechanism () for the drill bit. The rotary device includes a cam curve with a plurality of drive lobes (-) and working chambers () along a circumference in the rotation motor housing (), a rotor disc () carrying a plurality of radially movable vanes (-), which are accommodated in piston tracks (-) in the rotor disc. Characteristics of the rotary device are that it includes; an odd integer of a number of drive lobes (-), which is equal to or higher than three; an odd integer of a number of working chambers (), which is equal to or higher than three; an odd integer of a number of vanes (-), which is equal to or higher than three, and wherein said number of vanes are simultaneously pressurized in each working chamber ().

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Saltsjö-Boo, Sweden

Martin Öhnström