A tool head has a frame, a tool connected to the frame, an inner rotation manifold connected to the frame, a rotation motor that rotates a spindle, and an outer rotation manifold surrounding the inner rotation manifold. The outer rotation manifold is connected to the rotation motor in a fixed manner. The spindle continuously rotates the inner rotation manifold inside of the outer rotation manifold around an axis of the inner rotation manifold, and the frame and tool are rotated with inner rotation manifold.

A tool head has a frame, a tool connected to the frame, an inner rotation manifold connected to the frame, a rotation motor that rotates a spindle, and an outer rotation manifold surrounding the inner rotation manifold. The outer rotation manifold is connected to the rotation motor in a fixed manner. The spindle continuously rotates the inner rotation manifold inside of the outer rotation manifold around an axis of the inner rotation manifold, and the frame and tool are rotated with inner rotation manifold.

A timber-working device has a frame, and a saw apparatus mounted to the frame. At least one pair of arms are pivotally attached to the frame and configured to be controlled to grasp at least one tree stem. A feed mechanism is configured to feed the at least one stem relative to the frame. The feed mechanism has opposing feed arms, each feed arm pivotally connected to the frame. Each feed arm has a pivot pin arrangement with a first pivot pin and a second pivot pin, where the first pivot pin and the second pivot pin are aligned along a common longitudinal axis. An air gap is provided between the between the first pivot pin and the second pivot pin along the common longitudinal axis.

A timber-working device has a frame, and a saw apparatus mounted to the frame. At least one pair of arms are pivotally attached to the frame and configured to be controlled to grasp at least one tree stem. A feed mechanism is configured to feed the at least one stem relative to the frame. The feed mechanism has opposing feed arms, each feed arm pivotally connected to the frame. Each feed arm has a pivot pin arrangement with a first pivot pin and a second pivot pin, where the first pivot pin and the second pivot pin are aligned along a common longitudinal axis. An air gap is provided between the between the first pivot pin and the second pivot pin along the common longitudinal axis.

A saw apparatus includes a guide bar, a chain driver, and an endless cutting chain trained about the guide bar and the chain driver. A hydraulic chain tensioning apparatus has a hydraulic actuator configured to be driven by a hydraulic power source to act against the guide bar to maintain tension in the cutting chain. A tension release valve is provided between the hydraulic power source and the hydraulic actuator. The tension release valve has a check valve, and a manual override press-button configured to maintain the check valve in an open condition while depressed. The tension release valve has a spring detent configured to maintain the manual override press-button in a depressed condition until selectively released.

A saw apparatus includes a guide bar, a chain driver, and an endless cutting chain trained about the guide bar and the chain driver. A hydraulic chain tensioning apparatus has a hydraulic actuator configured to be driven by a hydraulic power source to act against the guide bar to maintain tension in the cutting chain. A tension release valve is provided between the hydraulic power source and the hydraulic actuator. The tension release valve has a check valve, and a manual override press-button configured to maintain the check valve in an open condition while depressed. The tension release valve has a spring detent configured to maintain the manual override press-button in a depressed condition until selectively released.

In a combination of a sprocket arrangement (128) and a saw chain (16), a sprocket tooth spacing (TI) between consecutive sprocket teeth (40) relates to a drive link spacing between consecutive drive links (30) of the saw chain (16) such that the guide teeth (42) of two or more drive links (30) may enter between a pair of consecutive sprocket teeth (40).

In a combination of a sprocket arrangement (128) and a saw chain (16), a sprocket tooth spacing (TI) between consecutive sprocket teeth (40) relates to a drive link spacing between consecutive drive links (30) of the saw chain (16) such that the guide teeth (42) of two or more drive links (30) may enter between a pair of consecutive sprocket teeth (40).

A work machine to cut timber including a control system, a felling head, a hydraulic motor configured to adjust the position of the felling head, and a spool valve operatively connected to the hydraulic motor, the spool valve being configured to move the felling head responsively through operation of the hydraulic motor. A machine controller coupled to the operator controller and the spool valve executes stored program instructions to generate a first control signal responsive to an operator control signal provided by the operator controller, generate a second control signal as a function of the generated first control signal, adjust a position of the spool of the spool valve in response to a concurrent receipt of the first control signal and the second control signal by the first proportional control valve and the second proportional control valve to move the felling head through operation of the hydraulic motor.

A work machine to cut timber including a control system, a felling head, a hydraulic motor configured to adjust the position of the felling head, and a spool valve operatively connected to the hydraulic motor, the spool valve being configured to move the felling head responsively through operation of the hydraulic motor. A machine controller coupled to the operator controller and the spool valve executes stored program instructions to generate a first control signal responsive to an operator control signal provided by the operator controller, generate a second control signal as a function of the generated first control signal, adjust a position of the spool of the spool valve in response to a concurrent receipt of the first control signal and the second control signal by the first proportional control valve and the second proportional control valve to move the felling head through operation of the hydraulic motor.