A chainsaw configured to be powered by a battery pack. The chainsaw includes a housing, a guide bar, and a power and drive assembly. The housing includes a battery interface for receiving the battery pack. The guide bar guides a cutting chain and is removably coupled to the housing. The power and drive assembly includes a motor and a gear train. The motor is disposed within the housing and is configured to be powered by the battery pack. The gear train is driven by the motor and configured to drive the cutting chain. The housing, the guide bar, and the power and drive assembly each contribute to a total weight of the chainsaw. A power output by the power and drive assembly compared to the total weight defines a power-to-weight ratio of above 150 Watts per Pound.

A chainsaw configured to be powered by a battery pack. The chainsaw includes a housing, a guide bar, and a power and drive assembly. The housing includes a battery interface for receiving the battery pack. The guide bar guides a cutting chain and is removably coupled to the housing. The power and drive assembly includes a motor and a gear train. The motor is disposed within the housing and is configured to be powered by the battery pack. The gear train is driven by the motor and configured to drive the cutting chain. The housing, the guide bar, and the power and drive assembly each contribute to a total weight of the chainsaw. A power output by the power and drive assembly compared to the total weight defines a power-to-weight ratio of above 150 Watts per Pound.

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.

Tensioning devices for maintaining tension in a chain of a chain saw are disclosed. The devices may include a housing adapted to be coupled to a drive cog of a chain saw, a saw bar mount adapted to be coupled to a saw bar of a chain saw, and at least one spring adapted to bias the saw bar mount in a distal direction from the housing, thereby tensioning the spring. The tensioning device may also include a ratchet and pawl assembly that allows the saw bar mount to be moved in the distal direction and stops movement of the saw bar mount in a proximal direction. The tensioning device may also include a lock adapted to hold the saw bar mount in a proximal position against a biasing force of the spring. Methods of assembling and operating tensioning devices are also disclosed.

Tensioning devices for maintaining tension in a chain of a chain saw are disclosed. The devices may include a housing adapted to be coupled to a drive cog of a chain saw, a saw bar mount adapted to be coupled to a saw bar of a chain saw, and at least one spring adapted to bias the saw bar mount in a distal direction from the housing, thereby tensioning the spring. The tensioning device may also include a ratchet and pawl assembly that allows the saw bar mount to be moved in the distal direction and stops movement of the saw bar mount in a proximal direction. The tensioning device may also include a lock adapted to hold the saw bar mount in a proximal position against a biasing force of the spring. Methods of assembling and operating tensioning devices are also disclosed.

A chain saw has a housing, a guiding plate, a chain, a power system and a tensioning component. The tensioning component includes a knob, a driving member and a transmission assembly. When the chain is in a loose state, the knob is forced to rotate and drives the transmission assembly to rotate, and the transmission assembly drives the driving member to rotate, then the driving member drives the guiding plate to move to tension the chain. When the chain is in an extension state, the knob is forced to rotate, the driving member stays still, and a skidding inside the tensioning component is generated. The tensioning component of the chain saw of the present invention can tension the chain and fix the guiding plate by rotating the knob, the operation is simple and convenient; Meanwhile, the tensioning component avoids over-tensioning the chain by skidding inside.

A chain saw has a housing, a guiding plate, a chain, a power system and a tensioning component. The tensioning component includes a knob, a driving member and a transmission assembly. When the chain is in a loose state, the knob is forced to rotate and drives the transmission assembly to rotate, and the transmission assembly drives the driving member to rotate, then the driving member drives the guiding plate to move to tension the chain. When the chain is in an extension state, the knob is forced to rotate, the driving member stays still, and a skidding inside the tensioning component is generated. The tensioning component of the chain saw of the present invention can tension the chain and fix the guiding plate by rotating the knob, the operation is simple and convenient; Meanwhile, the tensioning component avoids over-tensioning the chain by skidding inside.

A method and apparatus for vertically felling of trees are provided by taking apart the trunk in a stepwise manner combining sagittal and horizontal cross-sections. A vertical frame is attachable to a tree trunk, the vertical frame having a movable portion and a fixed portion. A first cutting device is attachable to the vertical frame and configured to cut the tree sagittally substantially along a longitudinal axis of the tree. A second cutting device is attachable to the vertical frame and configured to cut the tree horizontally from an exterior of the tree to a sagittal cut made in the tree by the first cutting device. A locking mechanism releasably locks the movable portion of the frame to the fixed portion of the frame. The apparatus uses the weight of the upper trunk to maintain stability to steadily decrease the tree height until the entire tree is removed.

A method and apparatus for vertically felling of trees are provided by taking apart the trunk in a stepwise manner combining sagittal and horizontal cross-sections. A vertical frame is attachable to a tree trunk, the vertical frame having a movable portion and a fixed portion. A first cutting device is attachable to the vertical frame and configured to cut the tree sagittally substantially along a longitudinal axis of the tree. A second cutting device is attachable to the vertical frame and configured to cut the tree horizontally from an exterior of the tree to a sagittal cut made in the tree by the first cutting device. A locking mechanism releasably locks the movable portion of the frame to the fixed portion of the frame. The apparatus uses the weight of the upper trunk to maintain stability to steadily decrease the tree height until the entire tree is removed.