A device (50) includes an i.c. engine (1) that can be held on a shoulder, for driving a shaft (3) inside a handle (2) via a flexible transmission (4). The shaft (3) operates, via a conic gear system (5), an operational group (8), supported by a head (7) fastened to the top of the handle (2). The operational group (8) includes a chain saw (81) geared with a pinion (84) keyed onto the exit of the conic gear system (5). The device (50) includes a system (40) for the lubrication of the chain saw (81), in which a diaphragm pump (43) is operated by the engine (1) so that the lubricant is withdrawn from a tank (41) and sent to a nozzle sprinkler (46) set under the chain saw (81) in the region of a groove (83a) into which appendixes extending from the chain run. <IMAGE>
