Abstract: A drive mechanism for driving a drum, such as a mulcher drum comprises an intermediate shaft coupled to drive the drum by way of a flexible coupling. The flexible coupling may be located on an inside of a hub of the drum. A hydraulic or other motor is coupled to drive the intermediate shaft by a splined coupling. Lubrication of the splined coupling is enhanced by a supply of grease contained in a central passage within the intermediate shaft. The drive mechanism may be direct drive from a hydraulic or other suitable motor. The drive mechanism can be compact and robust against collateral damage resulting from failure of drum support bearings.

Abstract: A system for measuring the length of a tree being processed through a delimber including a log feed roller mechanism for moving the tree, a delimbing head for delimbing the tree that is movable in a forward and reverse direction relative to the log feed roller mechanism, a measuring wheel resiliently mounted on the delimbing head, and a trimsaw movably mounted on the delimbing head. The length of the processed tree extending beyond the delimbing head may be calculated from signals encoded by the log feed roller mechanism and the measuring wheel. Logs may be cut from the tree by the trimsaw. Two photosensors located at known positions may be used to calculate the total length of the tree.

Abstract: A suspension for a tracked vehicle includes a bogie wheel assembly which has a pair of bogie wheels mounted to a walking beam. The walking beam is coupled to a body of the vehicle by a transversely-extending arm. The arm may be coupled to the body by a spherical bearing which permits angular rotation in at least two directions. The walking beam is connected to the body by shear members arranged in an inverted-V configuration. The shear members may be elastomeric springs.

Abstract: A suspension for a tracked vehicle includes a bogie wheel assembly which has a pair of bogie wheels mounted to a walking beam. The walking beam is coupled to a body of the vehicle by a transversely-extending arm. The arm may be coupled to the body by a spherical bearing which permits angular rotation in at least two directions. The walking beam is connected to the body by shear members arranged in an inverted-V configuration. The shear members may be elastomeric springs.

Abstract: A system for measuring the length of a tree being processed through a delimber including a log feed roller mechanism for moving the tree, a delimbing head for delimbing the tree that is movable in a forward and reverse direction relative to the log feed roller mechanism, a measuring wheel resiliently mounted on the delimbing head, and a trimsaw movably mounted on the delimbing head. The length of the processed tree extending beyond the delimbing head may be calculated from signals encoded by the log feed roller mechanism and the measuring wheel. Logs may be cut from the tree by the trimsaw. Two photosensors located at known positions may be used to calculate the total length of the tree.

Abstract: A feed roll for tree handling has a number of strips which substantially cover its outer face. The strips have leading and trailing edges shaped to interdigitate with one another. A layer of resilient or slippery material is located between the strips and a drum. The strips can rock slightly.

Abstract: A hydraulic circuit for a tree-cutting machine having a feed mechanism powered by hydraulic fluid at the output of a hydraulic motor. The hydraulic motor may comprise a variable-displacement motor. The hydraulic circuit may comprise elements which provide an anti-stall mode, wherein the feed mechanism is operated to withdraw the cutting element upon pressure at an input port of the hydraulic motor exceeding a threshold.

Abstract: A feed roll for tree handling has a number of strips which substantially cover its outer face. The strips have leading and trailing edges shaped to interdigitate with one another. A layer of resilient or slippery material is located between the strips and a drum. The strips can rock slightly.

Abstract: A feed roll for tree handling has a number of resiliently mounted strips which substantially cover its outer face. The strips have leading and trailing edges shaped to interdigitate with one another. A layer of resilient material is located between the strips and a drum. The resilient material has a hardness of 80 or less on the Shore scale.

Abstract: An off-road vehicle has an undercarriage and a superstructure and a tilting mechanism for levelling the superstructure. The tilting mechanism comprises upper and lower members coupled to tilt about a tilt axis by a hinge. The lower member is pivotally mounted to the undercarriage. A brake allows the orientation of the tilt axis relative to the undercarriage to be locked. The tilt mechanism allows the superstructure to be levelled by a method which includes the steps of releasing the brake, rotating the lower member until the tilt axis is horizontal, and tilting the upper member about the tilt axis until the superstructure is level. The tilting mechanism is simple and provides a full range of tilt in all directions. A tilting mechanism may be retrofitted to existing vehicles.

Abstract: The invention provides a drive system for extending or retracting a boom. The boom comprises an elongated boom slidably mounted to a vehicle. The drive system comprises: a flat belt extending generally parallel to the boom; a rotatable drum mounted to the vehicle; and a pair of spaced apart rollers adjacent the rotatable drum. The belt is attached to the boom by couplings at either end of the belt. A loop of the belt extends through a gap between the pair of spaced apart rollers and around an outer circumference of the rotatable drum. The gap has a width less than a diameter of the rotatable drum. The drive system can be used to advantage in a forestry machine such as a tree delimber.

Abstract: A Snubber is used to damp the swing of the door on an excavator bucket to prevent the door form being damaged by repeatedly slamming shut. The snubber has housing which mounts to an excavator bucket and a shaft pivotally mounted in the housing and connected to an excavator door. The shaft turns when the excavator door opens. The housing has a cylindrical cavity around the shaft. The cavity is divided into two volumes by a dam and a wiper arm on the shaft. The wiper arm forces hydraulic fluid to flow through an orifice between the volumes as the shaft turns. The wiper arm has end seals which seal against end walls of the cavity. The end seals are forced outwardly by hydraulic pressure when the door is closing. A one-way valve allows hydraulic fluid to bypass the orifice while the door is opening. The snubber requires less maintenance than previous friction snubbers.

Abstract: A Snubber is used to damp the swing of the door on an excavator bucket to prevent the door form being damaged by repeatedly slamming shut. The snubber has housing which mounts to an excavator bucket and a shaft pivotally mounted in the housing and connected to an excavator door. The shaft turns when the excavator door opens. The housing has a cylindrical cavity around the shaft. The cavity is divided into two volumes by a dam and a wiper arm on the shaft. The wiper arm forces hydraulic fluid to flow through an orifice between the volumes as the shaft turns. The wiper arm has end seals which seal against end walls of the cavity. The end seals are forced outwardly by hydraulic pressure when the door is closing. A one-way valve allows hydraulic fluid to bypass the orifice while the door is opening. The snubber requires less maintenance than previous friction snubbers.

Abstract: A combined tree feller processor has a head mounted to a boom with a three-axis coupling. The coupling allows an operator to control the orientation of the head. The head has tree processing means and a continuously rotating high speed saw for cutting trees. While trees are being cut the head is held firmly with respect to rotation about a third generally vertical axis. After a tree has fallen the third axis is in a horizontal position and is perpendicular to the longitudinal axis of the head. The head is allowed to float with respect to the third axis as the tree is processed.