The object of the invention is to provide a drilling device which is compact and has good sliding properties. The object is achieved by an upper beam for use with a lower beam in a telescopic feeder for a drilling device for rock drilling. The upper beam extends along a longitudinal axis and has a generally U-shaped cross section comprising a bottom wall and a first and a second side wall. Each side wall has an inward surface and an outward surface. The upper beam comprises a cooperating member intended for sliding cooperation with the lower beam. The cooperating member comprises an attachment structure extending outwardly from each outward surface of each side wall. Each attachment structure is intended for fixed mounting of a crank block bracket, which crank block bracket faces the outward surface of each side wall.