Abstract: A rock drill bit includes at least one leg about which a roller cutter is rotatably mounted. A ring-shaped seal is disposed between an end surface of the leg and a sealing surface of the roller cutter. The seal is arranged coaxially with respect to an axis of rotation of the roller cutter and is formed of an elastic material and a relatively rigid material embedded within the elastic material. The elastic material defines first and second surfaces which engage the leg and the roller cutter, respectively. Either the leg or the seal includes circumferentially spaced recesses which receive respective projections formed in the other of the leg and the seal, for locking the seal to the leg against rotation relative thereto.

Abstract: A rotary cutter includes a shaft adapted to be mounted on a support and defining a longitudinal axis. The shaft includes a bore extending inwardly into the shaft, and a channel extending into the shaft and intersecting the bore. A roller body, having cutting elements, is mounted on the shaft for rotation relative thereto about the axis. Bearings are disposed between the roller body and the shaft, the bearings communicating with the bore. The cutter is lubricated by inserting a filling plug into the bore and forcing lubricant therethrough and into the bearings. The filling plug is then removed from the bore, leaving the bore generally free of lubricant. A hollow cylindrical member and a flexible diaphragm are inserted into the bore, and a nozzle is inserted through the channel for introducing lubricant into the bore. The nozzle is then removed from the channel, and the channel is plugged. The diaphragm flexes inwardly and outwardly in response to variations in external and internal pressures.

Abstract: In a method for use in dry, rotary, crushing full-area drilling, use is made of suction air alone for removing cuttings produced during drillings. To carry out the method, two suction nozzles (13) are arranged on the underside of a cutterhead (1). These nozzles together have a substantially diametrical extent and the length of a radius on the cutterhead and are provided with suction intakes (14A) in the vicinity of the periphery of the cutterhead. The suction intakes (14A) are connectible a common suction channel (11) in the drill string (6) of the cutterhead. The suction channel (11) has substantially constant diameter.