Abstract: A forwarder has an elongate rigid chassis with a cab at a forward end, a load carrier on the chassis, and a crane serving the load carrier. Four wheels at the front are mounted as a pair on each side, each pair on a common yoke to form a bogie. The bogies can pivot relative to the chassis for up and down movement of the wheels, but the wheels are non-steerable. A single wheel at each side at the rear of chassis is steerable, to provide steering of the forwarder. The cab, the operator, the load lifting device and the load carrier always have the same, fixed, orientation at all times.

Abstract: A rotator for crane-mounted working implements comprises a housing (7) swingably connectible with the tip of the crane via a joint, and a pivot shaft (8) connectible with the working implement and pivotal relative to said housing by means of at least one vane or flap (10) operating in a chamber and dividing said chamber into two operating chambers which can be supplied with, or evacuated of, hydraulic medium via two first ducts (12) provided in said housing, said pivot shaft including second hydraulic medium through-ducts (17, 17') opening into annular hollow spaces (16, 16') in a swivel connection (15) incorporated in said housing.

Abstract: The invention relates to a method for handling and transporting logs from felling site to consumer, the logs being loaded at the felling site on a cross-country vehicle (1) which carries the logs to a landing where they are unloaded and loaded anew, viz. on a road vehicle which tranports the logs to the consumer. The logs loaded on the road vehicle (1) are bundled, preferably already at the felling site, by means of chains (17) to form a bundle of logs which is maintained intact or unbroken during reloading from the cross-country vehicle (1) to the road vehicle.

Abstract: A forest machine with a crane comprises a driver's cab (2) which is mounted on a wheeled chassis (1) and behind which a load carrier (3) is placed, and a crane post (10) mounted in association with the cab and rotatable relative to the chassis and carrying an outer boom (11) having a telescopic boom (16) which is arranged at its free end to carry a working tool (21). The crane post (10) comprises two suitably inclined, spaced-apart support arms (12) between which extends a pivot shaft (13) on which the outer boom is mounted in a position between the support arms. The pivot shaft (13) is located at a distance from the center of rotation of the post (10) exceeding half the distance between a pair of wheels carrying the chassis of the machine. The outer boom is movable through at least 90.degree. between a horizontal and a vertical position, more precisely by means of a hydraulic cylinder (19).

Abstract: The invention relates to a method for thinning a forest by means of a wheeled harvester and a wheeled forwarder comprising a driver's cab and a load carrier located behind the cab. The harvester (3) is caused to advance in existing forest stands (1) in routes optimally selectable with regard to the characteristics of the stand, between main haul roads or strip roads close to each other, and is parked on suitable places along the routes for felling trees on each parking place. The trees are limbed and placed underneath the harvester between the wheels thereof, and the forwarder (4) is caused to follow the harvester in the same route as this and take care of the tree stems placed underneath the harvester and left behind it. This is achieved in that the felled trees lying in front of the forwarder are lifted by it and moved over and rearwards past the cab of the forwarder to the load carrier situated behind the cab.

Abstract: A feeding device for longitudinally feeding a tree stem comprises a breast part (2, 2') to be applied against the stem, and two separate feeding units (3, 3'), suitably in the form of endless chains which are movable towards and away from each other, such that they can be pressed against opposite sides of the stem. Each feeding unit is mounted on a holder (7) which is connected to a frame (1) carrying the breast part, by means of a parallel arm system comprising two arms (8, 9) each connected to the holder (7) and the frame (1) by joints 10, 11, 12, 13) whose axes of rotation extend at an acute angle to the axes of rotation of the feeding units. A piston and cylinder assembly (14) is mounted in a conventional way between diagonally opposite joints in the parallel arm system for pivoting the arms relative to the frame for automatically centering the device relative to the tree stem irrespective of varying stem diameters.

Abstract: The invention relates to a device for maintaining a tool attachment in a knuckle boom crane, preferably for forest machines, on a constant level above the ground. The knuckle boom comprises a main boom which can be raised and lowered by means of a double-acting hydraulic cylinder (4), and an outer boom pivotal relative to the main boom my means of a likewise double-acting hydraulic cylinder (6). To ensure the vertical adjustment of the tool attachment, the lift cylinder (4) is connectible to the outer boom cylinder (6) via a compensator (21) in such a manner that an amount of hydraulic fluid which is proportional to the amount of hydraulic fluid which upon activation of the outer boom is pressed out from the lifting or the lowering side, respectively, of one of the cylinders (4, 6), is pressed into the lowering or the lifting side, respectively, of the other cylinder.

Abstract: An assembly for limbing tree stems comprises two limbing tools (53, 53') movable towards and away from each other, and two feeding units (1, 1') which are also movable towards and away from each other and arranged for longitudinal feeding of individual stems past the limbing tools limbing the stems. Each limbing tool (53) is connected to an associated feeding unit (1) and arranged to follow this unit when moving towards and away from the stem. Further, the limbing tool is located substantially in the extension of the contact surface of the feeding unit with respect to the stem. The feeding units and the limbing tools are movable towards and away from each other in a common plane to which rotary shafts for driving the feeding units are provided at right angles. Each limbing tool is mounted on at least one arm which is articulated or pivotally connected to a frame for the feeding unit.

Abstract: A feeding device for effecting a longitudinally directed relative movement between a stem and the device proper comprises at least one feeding unit in the form of an endless band or band-like element which is drivable by means of at least one rotatable wheel. The endless element is composed of a large number of hingedly interconnected chain-forming links (11, 12) which are movable along the outer side or the periphery of an elongate guide bar and which, by bearing against said bar (10), are adapted to transfer substantially uniformly distributed bearing pressures to the stem substantially throughout the length of said bar.

Abstract: A machine for limbing trees arranged in bundles including two alternatingly cooperating carriers (8, 9), at least one carrier (8) including a number of rotatable, suitably cylindrical, limbing means (10), means being associated to the carriers to transfer the separate bundle of trees from one carrier to another and vice versa, thus loosening the bundle in order to revolve the trees and successively bring unlimbered parts of the trees into contact with said limbing means (10).

Abstract: The invention relates to a mobile thinning machine. It comprises according to the invention a two-wheeled drive unit (1) with motor and hydraulic unit and a logging unit (2) carried on a dirigible and driven supporting wheel (5), with driver's cab (8), pivotal boom (13), felling unit (15) and clamping bunk (20). The logging unit (2) is connected to the drive unit via an articulate frame steering (21) with a bracket (22) and a telescopic arm (24) extending therefrom. The articulate frame steering (21) permits the two units (1,2) to be put at an angle of more then 90.degree. relative to each other. The telescopic arm (24) houses necessary hydraulic and electric lines all the way to the logging unit (2) for operating this unit from the driver's cab (8). The telescopic arm (24) can be moved back over the drive unit (1), so that this unit together with the logging unit (2) forms a compact three-wheeled vehicle for transport between the thinning places.

Abstract: A bundle limbing device, primarily for mobile use, is divided into two mirror-symmetrical halves, each with one front and one rear swinging arm (4a,4b) at their lower parts mounted on a low level of a forwarder and interconnected by means of longitudinal bars (14a,14b). At the ends of the swinging arms of each device half, front and rear bearing beams (6a,6b) are rigidly secured, which serve as bearings for a series of parallel limbing rolls (8). Support shoulders (13a,13b) at the top of the swinging arms form side supports for a bundle of trunk portions (12) which are deposited on the bed formed as the two device halves are brought together, when the opposite bearing beams (6a,6b) on the associated swinging arms meet and form an obtuse angle. Each limbing roll consists of a center tube (9) which supports a series of circular annular flanges (10) with alternating inclination to the tube shaft defining an elliptic rotational surface.

Abstract: The invention relates to a method at the cross-cutting of tree stems to pre-determined timber lengths. According to the invention, an impulse is triggered when the nominal timber length has been attained, which impulse stops the advance movement and braking is effected while the braking energy is accumulated all the way to the stop of the stem after the stem has moved through a certain distance beyond the nominal length. The accumulated braking energy then is released for moving the stem back to substantially the nominal length, whereafter the cross-cutting is carried out. At an apparatus for carrying out the method according to the invention, the feeding wheels (2) of the stem (1) are driven by hydraulic motors (7) having a pressure conduit (5) and a return conduit (6) in common. The return conduit is connected to a pressure accumulator (9). A stop valve (8) is laid-in in each conduit (5,6).

Abstract: The invention relates to a device at a rotator and grapple unit intended for tree handling and suspended at the end of a boom. The rotator (8) and grapple (11) are connected each to a pair of flexible operating lines (6,7 and, respectively, 9,10) from a hydraulic pump (1) via a control valve (3). For rendering possible completion of the unit with a hydraulic sawing device without adding two additional hydraulic hoses for this purpose, which would give rise to problems due to the combined bending and rotary movement at the crane tip and resulting heavily increased strains and wear on a bundle consisting of six hoses, according to the invention a branch line (13) is taken from the operating line (10) used for closing the grapple (11), which branch line is located in a place after the rotator (8). The branch line (13) extends to a hydraulic sawing device (15,16) via a pressure-sensing valve (14).

Abstract: The invention relates to a device for preventing length measuring errors resulting from accidentally remaining local offshoots from a portion of the butt end of a tree stem which is continuously advanced toward a cross-cutting member for cutting the stem in predetermined length sections. A stem-measuring device periodically emits a cutting impulse to the cross-cutting member so that the advancing stem will be cut into predetermined lengths. Two detectors are provided in a spaced relationship for sensing the entering of the butt end into a detecting station and then emitting an actuating signal to start the measuring device. The spacing of the two detectors, which are symmetrically positioned with respect to the centerline of the stem path, does not exceed a predetermined minimum butt diameter. The measuring device is not actuated until signals from both detectors are emitted.