Drilling equipment of different kinds generate sound, and especially heavy drill equipment such as rock drill rigs used for surface or underground drilling.
Generally, a rock drill rig (FIG. 1) comprises a movable carrier, a boom and a feed beam connected to the boom via e.g. a feed beam holder. The feed beam and the feed beam holder are movable in relation to each other along at least part of the length of the feed beam, to enable relative movement between the feed beam and the boom. A drilling machine is movable along the feed beam, affecting the drill string to be forced into the ground. The drill string comprises the drill point (drill bit) and the joined rods.
Disturbing sound is for instance generated at the drilling machine and at the drill point. It is therefore desirable to dampen the generated sound to the surroundings. Various arrangements for screening off the sound generated at the drilling machine are known.
U.S. Pat. No. 3,667,571 discloses a multilayer housing enclosing the drilling equipment and the feed beam. The feed beam is suspended in the housing via dampening members, thereby making the positioning and the whole construction unstable and not applicable in modern drill rigs.
WO02/070856 discloses a housing of flexible sheets that encloses the drilling equipment and the feed beam. A longitudinal opening is arranged, which enables the operator to monitor the drilling process and to scarf rods to the drill string. The housing is fastened to the feed beam via bars. It is assumed that the elongated opening, to a certain degree, leaks sound to the surroundings. Furthermore, the smaller the opening is made to reduce the noise, the harder it gets for the operator to monitor and scarf (join) the rods.
JP5079271 shows another type of housing, enclosing a drill machine that is movable on a feed beam.
WO00/39412 discloses a housing arranged to the feed beam, enclosing the drilling equipment and the feed beam, and it may also enclose the feed beam holder. The housing is attached to the feed beam via brackets, and is arranged with an opening for enabling the movement between the feed beam and the boom. The opening is arranged with a so called “noise curtain” of e.g. bristles to seal the opening. Despite the noise curtain, sound is spread to the environment through the opening. Furthermore, the hatches arranged in the housing are relatively small, which makes it difficult to monitor e.g. scarfing.
A major drawback of the prior art housings is that they fail in enabling sound dampening of the sound generating parts and at the same time allow for relative movement between the feed beam and the feed beam holder.