A chain bar unit for a wall saw is presented herein. The chain bar unit can include a bar configured to receive a circulating chain or wire around a perimeter of the bar. The chain bar unit also can include a driving gear for driving the chain or wire around the bar, the driving gear configured to be coupled to an output shaft of the wall saw. The chain bar unit further includes the bar being tapered from an end proximate to the driving gear to a distal end having a distal end radius, wherein a width of the bar at the proximate end, is at least two times the distal end radius of the distal end.

A chainsaw includes a sprocket coupled to a chain and configured to drive the chain, wherein the sprocket comprises a receiving area defining a drive surface; a clutch disposed at least partially in the receiving area of the sprocket, wherein the clutch comprises: a hub defining a central axis, the hub being rotationally keyed to an output shaft of a motor; a centrifugal weight disposed between the hub and the sprocket and movable in a radial direction relative to the central axis; and a spring compressed between the hub and the centrifugal weight to bias the centrifugal weight in a radial direction towards the central axis; wherein the centrifugal weight comprises a drive feature on a radially outer surface, and wherein the drive feature is configured to selectively interface with the drive surface of the sprocket when the output shaft is rotating above a threshold rotational speed.

A chainsaw includes a sprocket coupled to a chain and configured to drive the chain, wherein the sprocket comprises a receiving area defining a drive surface; a clutch disposed at least partially in the receiving area of the sprocket, wherein the clutch comprises: a hub defining a central axis, the hub being rotationally keyed to an output shaft of a motor; a centrifugal weight disposed between the hub and the sprocket and movable in a radial direction relative to the central axis; and a spring compressed between the hub and the centrifugal weight to bias the centrifugal weight in a radial direction towards the central axis; wherein the centrifugal weight comprises a drive feature on a radially outer surface, and wherein the drive feature is configured to selectively interface with the drive surface of the sprocket when the output shaft is rotating above a threshold rotational speed.

A working machine is provided that includes a working portion and a main body portion including a main body case, an operation mechanism and a power switch. The operation mechanism includes a trigger lever, a lockout lever, and a restricting portion. The trigger lever includes a trigger lever body, and an operation portion including a projection portion. When an external force toward the main body case is applied to the trigger lever body, the projection portion of the operation portion comes into contact with the restricting portion and the trigger lever body comes into contact with the lockout lever, so that the trigger lever body is prevented from rotating relative to the main body case. When the working machine is viewed from a normal direction of a flat surface while being placed on the flat surface, a rotation center of the trigger lever body overlaps with the power switch.

A working machine is provided that includes a working portion and a main body portion including a main body case, an operation mechanism and a power switch. The operation mechanism includes a trigger lever, a lockout lever, and a restricting portion. The trigger lever includes a trigger lever body, and an operation portion including a projection portion. When an external force toward the main body case is applied to the trigger lever body, the projection portion of the operation portion comes into contact with the restricting portion and the trigger lever body comes into contact with the lockout lever, so that the trigger lever body is prevented from rotating relative to the main body case. When the working machine is viewed from a normal direction of a flat surface while being placed on the flat surface, a rotation center of the trigger lever body overlaps with the power switch.

A working machine is provided that includes a working portion and a main body portion including a main body case, an operation mechanism and a power switch. The operation mechanism includes a trigger lever, a lockout lever, and a restricting portion. The trigger lever includes a trigger lever body, and an operation portion including a projection portion. When an external force toward the main body case is applied to the trigger lever body, the projection portion of the operation portion comes into contact with the restricting portion and the trigger lever body comes into contact with the lockout lever, so that the trigger lever body is prevented from rotating relative to the main body case. When the working machine is viewed from a normal direction of a flat surface while being placed on the flat surface, a rotation center of the trigger lever body overlaps with the power switch.

A working machine is provided that includes a working portion and a main body portion including a main body case, an operation mechanism and a power switch. The operation mechanism includes a trigger lever, a lockout lever, and a restricting portion. The trigger lever includes a trigger lever body, and an operation portion including a projection portion. When an external force toward the main body case is applied to the trigger lever body, the projection portion of the operation portion comes into contact with the restricting portion and the trigger lever body comes into contact with the lockout lever, so that the trigger lever body is prevented from rotating relative to the main body case. When the working machine is viewed from a normal direction of a flat surface while being placed on the flat surface, a rotation center of the trigger lever body overlaps with the power switch.