Abstract: The object of the invention is an apparatus for clamping a chipper knife (1) to a rotatable chipper disc (4) or drum so that the back surface (6) of the knife (1) is supported against a knife clamp (2) with a knife spacer (3), and that the knife clamp (2) and knife spacer (3) are movable relative to each other by means of the clamping element (5). The knife clamp (2) is provided with supporting surfaces (11, 12) which the back surface (6) of the knife (1) is adapted to lean against by at least two spaced-apart surfaces (11', 12'). The knife spacer element (3) includes a supporting surface (13) which is adapted to subject a front surface (14) of the knife (1) to a force acting between said supporting surfaces (11, 12) of the knife clamp (2) for bending the knife (1) between said supporting surfaces (11, 12) of the knife clamp (2) towards the knife clamp (2) so as to generate a compression stress in the free section of a front surface (16) of the knife (1).

Abstract: A knife (12) are a holding and releasing mechanism (8) are oriented in the direction of a radius of a chipper disc (19). The holding and releasing mechanism (8) is pushed in the direction of the radius of the chipper disc to release the knife (12) and drawn in the opposite direction to fasten the knife in the chipper disc (19). The time consumed in replacing the knives is reduced and laborious manual operations can be avoided. The procedure can be automated.

Abstract: A counter blade is disclosed for use in a chipping machine which comprises a chipper disc rotatably mounted in the chipper frame by means of a shaft supporting the disc. The counter blade is attached to the chipper frame essentially at the intersection of a blade mounted in the chipper disc and the log to be chipped, in such manner that, on the side opposite to the chipping blade, the counter blade rests against the log to be chipped. The counter blade consists of a first and a second blade part placed at an obtuse angle relative to each other. According to the present invention, the counter blade consists of two essentially elongated elements having an arris forming the cutting edge of the counter blade at least on one of its longitudinal sides. The end faces of the counter blade elements are so formed as to permit connection to an adjacent counter blade element so that two counter blades form a continuous cutting edge of the counter blade.

Abstract: A disk chipper for the production of wood chips, consisting of a rotatable chipping disk supported on an axle driven by at least one drive machine. The disk chipper of the invention is so implemented that at least three motors are drivably coupled to the axle of the chipping disk by means of a gear assembly, preferably a spur gear assembly.

Abstract: A device is disclosed for separating hard objects, such as stones, from a stream of wood in an apparatus for conveying or manipulating logs or blocks of wood including a conveyor section. The device includes a transducer disposed in a location suited for the detection of vibration. The transducer registers acoustic vibrations and is connected to a control unit by means of which hard objects conveyed along with the wood stream can be detected on the basis of the vibration signals they generate. The control unit is also used to control an exit gear incorporated in the conveyor section, so that hard objects which are detected will fall down from the stream of wood passing through the apparatus. The invention eliminates the need to build water-operated stone catchers as conventionally used for the removal of stones.

Abstract: For supplying pressurized steam into a rotating barking drum during the barking of tree trunks in order to thaw and warm the bark, steam is supplied into the barking drum from the periphery of the drum in a substantially radial direction through a distribution ring on the periphery of the drum and a stationary member in sliding contact with the ring.