A working machine has an oil groove communicating a pump chamber with a gear chamber, and a small amount of oil is delivered to the gear chamber when oil is discharged from the pump chamber. Thus, the oil adheres to the outer peripheral surface of a rotating pump shaft and is kept remaining between a pump case and the pump shaft. Therefore, the viscosity is increased and a pressure loss between the pump chamber and the gear chamber is increased. Accordingly, the airtightness can be maintained, and the stable and inexpensive oil pump mechanism requiring less man-hour can be realized without depending on the accuracy of a gap between the pump case and the pump shaft. Since oil is kept remaining on the outer peripheral surface of the pump shaft, it is possible to prevent the pump case from being worn out and to improve the durability of components.

A chainsaw includes a chainsaw body, a guide bar and a saw chain. The chainsaw body includes an oil tank, an oil pump to supply oil stored in the oil tank to a sliding portion between the guide bar and the saw chain, a first extension chamber arranged above the oil tank and a second extension chamber arranged above the first extension chamber. The oil tank communicates with the first extension chamber via a first flow path, the first extension chamber communicates with the second extension chamber via a second flow path and a vent hole communicating with the outer space is formed in the second extension chamber.

A chainsaw includes a chainsaw body, a guide bar and a saw chain. The chainsaw body includes an oil tank, an oil pump to supply oil stored in the oil tank to a sliding portion between the guide bar and the saw chain, a first extension chamber arranged above the oil tank and a second extension chamber arranged above the first extension chamber. The oil tank communicates with the first extension chamber via a first flow path, the first extension chamber communicates with the second extension chamber via a second flow path and a vent hole communicating with the outer space is formed in the second extension chamber.

A lubrication system for a chainsaw, the lubrication system including a reservoir housing a lubricant, a fluid conduit extending between the reservoir and a location adjacent to a chain of the chainsaw, a pump configured to move lubricant from the reservoir to the location adjacent to the chain, and a valve disposed along the fluid conduit. The valve has a lubricant inlet that receives lubricant from the reservoir, an air inlet, and an outlet that provides lubricant to the location adjacent to the chain. The valve is movable between an open position whereby lubricant passes from the lubricant inlet to the outlet and a closed position whereby the outlet is in fluid communication with the air inlet. The valve moves between the open and closed positions in response to a user input.

A lubrication system for a chainsaw, the lubrication system including a reservoir housing a lubricant, a fluid conduit extending between the reservoir and a location adjacent to a chain of the chainsaw, a pump configured to move lubricant from the reservoir to the location adjacent to the chain, and a valve disposed along the fluid conduit. The valve has a lubricant inlet that receives lubricant from the reservoir, an air inlet, and an outlet that provides lubricant to the location adjacent to the chain. The valve is movable between an open position whereby lubricant passes from the lubricant inlet to the outlet and a closed position whereby the outlet is in fluid communication with the air inlet. The valve moves between the open and closed positions in response to a user input.

A chainsaw apparatus has a guide bar, a drive sprocket, and endless cutting chain mounted over the guide bar and over the drive sprocket, a first motor drivingly connected to the drive sprocket so as to cause the drive spot sprocket to move the endless chain over the guide bar, the first control device for controlling operation of the first motor and configured to deliver at least one first data representative of an operation of the motor, a storage tank suitable adapted to receive a lubricating fluid therein, a pump cooperative with the storage tank so as to deliver the lubricating fluid toward the guide bar and the endless cutting chain, a second motor drivingly connected to the pump, and a second control device for controlling operation of the second motor on the basis of a lubricating control parameter derived from the first data. The second motor is an electric motor.

A chainsaw apparatus has a guide bar, a drive sprocket, and endless cutting chain mounted over the guide bar and over the drive sprocket, a first motor drivingly connected to the drive sprocket so as to cause the drive spot sprocket to move the endless chain over the guide bar, the first control device for controlling operation of the first motor and configured to deliver at least one first data representative of an operation of the motor, a storage tank suitable adapted to receive a lubricating fluid therein, a pump cooperative with the storage tank so as to deliver the lubricating fluid toward the guide bar and the endless cutting chain, a second motor drivingly connected to the pump, and a second control device for controlling operation of the second motor on the basis of a lubricating control parameter derived from the first data. The second motor is an electric motor.

The present disclosure relates to a lubrication monitoring system (15) configured to monitor a supply of lubricant in a hand-held cutting tool (1) having a cutting unit (3, 5). A lubricant tank (41) and a conduit (45) are configured to duct a flow of lubricant from the tank (41) to the cutting unit (3, 5). The lubrication monitoring system (15) comprises a heating element (29) and a sensor arrangement (31, 33), the heating element (29) being configured to heat the lubricant flow. The sensor arrangement comprises a first sensor (31) located at the flow, upstream of the heating element (29), and a second sensor (33) located at said flow, downstream of the heating element. The lubrication monitoring system outputs a monitoring signal based on a sensed temperature difference between the first and second sensors (31, 33).

The present disclosure relates to a lubrication monitoring system (15) configured to monitor a supply of lubricant in a hand-held cutting tool (1) having a cutting unit (3, 5). A lubricant tank (41) and a conduit (45) are configured to duct a flow of lubricant from the tank (41) to the cutting unit (3, 5). The lubrication monitoring system (15) comprises a heating element (29) and a sensor arrangement (31, 33), the heating element (29) being configured to heat the lubricant flow. The sensor arrangement comprises a first sensor (31) located at the flow, upstream of the heating element (29), and a second sensor (33) located at said flow, downstream of the heating element. The lubrication monitoring system outputs a monitoring signal based on a sensed temperature difference between the first and second sensors (31, 33).

A chainsaw includes a housing; a first motor supported by the housing; a saw chain driven by the first motor to implement a cutting function; a guide bar, where an end of the guide bar is supported by the housing and the guide bar is used for supporting and guiding the saw chain; an oil pump assembly including an oil pump for pumping lubricants to lubricate the saw chain or the guide bar and an oil can for storing the lubricants; and a second motor for driving the oil pump, where the distance between the center of gravity of the first motor and the center of gravity of the second motor is less than or equal to 1 m.