A method for controlling a DC pump motor, preferably a brushed DC motor for pumping lubricant, which motor is controlled by a pulse-width modulated (PWM) control signal, wherein current parameters are acquired in an acquisition step and a duty cycle (D) of the PWM control signal (S.sub.PWM) is adapted and/or changed on the basis of the detected parameters in an adaptation step, wherein the acquisition of current parameters comprises at least the acquisition of a current input voltage (U.sub.B).

Systems and methods which provide control of lubricant delivery with respect to chainsaws using a lubricant flow shutoff valve controlled in correspondence to an operational state of the chainsaw are described. A chainsaw lubricant delivery control system may include a lubricant flow shutoff valve and a chainsaw operation-based valve controller operable cooperatively to provide control of lubricant delivery to the cutting chain and guide bar assembly of a chainsaw. The chainsaw operation-based valve controller may be coupled to an operationally active element of the chainsaw wherein the chainsaw operation-based valve controller may control the lubricant flow shutoff valve between an open position and a closed position responsive to detecting a particular state of the operationally active element corresponding to an operational state of the chainsaw. Chainsaw lubricant delivery may prevent or otherwise discourage unintended leakage of lubricant from the chainsaw lubrication system.

Systems and methods which provide control of lubricant delivery with respect to chainsaws using a lubricant flow shutoff valve controlled in correspondence to an operational state of the chainsaw are described. A chainsaw lubricant delivery control system may include a lubricant flow shutoff valve and a chainsaw operation-based valve controller operable cooperatively to provide control of lubricant delivery to the cutting chain and guide bar assembly of a chainsaw. The chainsaw operation-based valve controller may be coupled to an operationally active element of the chainsaw wherein the chainsaw operation-based valve controller may control the lubricant flow shutoff valve between an open position and a closed position responsive to detecting a particular state of the operationally active element corresponding to an operational state of the chainsaw. Chainsaw lubricant delivery may prevent or otherwise discourage unintended leakage of lubricant from the chainsaw lubrication system.

A pump (1) comprising a lubricant reservoir (3) which feeds at least one pumping element (2), the reservoir (3) being delimited by a base (4) in correspondence with which, inside the reservoir (3) there is a rotating spatula (5) featured, equipped with at least one blade (5A) which, by rotating over the base (4), conveys the said lubricant towards an intake (2A) in the said pumping element (2) pushing the said lubricant through a plurality of passages (4A) made in the surface of the said base (4).

A pump (1) comprising a lubricant reservoir (3) which feeds at least one pumping element (2), the reservoir (3) being delimited by a base (4) in correspondence with which, inside the reservoir (3) there is a rotating spatula (5) featured, equipped with at least one blade (5A) which, by rotating over the base (4), conveys the said lubricant towards an intake (2A) in the said pumping element (2) pushing the said lubricant through a plurality of passages (4A) made in the surface of the said base (4).

A fluid delivery system includes a reservoir for storing fluid, a rotary pump having a first pump port and a second pump port, a first fluid conduit connecting the first pump port to the reservoir, and a second fluid conduit connecting the second pump port to the reservoir. The rotary pump rotates in a first delivery direction in a normal mode and in a second delivery direction in an alternative mode. A first valve separates the first pump port from the reservoir when the rotary pump is in its alternative mode, and a second valve separates the second pump port from the reservoir when the rotary pump is in its normal mode.

The invention relates to a lubricant dispenser comprising a storage container (1) filled with lubricant and a pump (2) which is connected to or can be connected to the storage container (1) and by means of which the lubricant can be pumped out of the storage container (1). The pump has a pump housing (3) with an inlet opening (4) and an outlet opening (5), a piston (6) which is movably guided in the pump housing (3) in a linear manner, and a drive (7) which acts on the piston (6). The pump housing (3) of the pump (2) is connected to or can be connected to the storage container (1), and the piston (6) can be raised or lowered cyclically by the drive (7) in order to pump a lubricant from the inlet opening (4) to the outlet opening (5). The lubricant dispenser is characterized in that the piston (6) is designed in a stepped manner with an upper piston surface (10) which delimits an upper displacement chamber (8) and a lower piston surface (11) which delimits a lower displacement chamber (9) and is reduced compared to the upper piston surface (10). The upper displacement chamber (8) adjoins the inlet opening (4) via a first valve (13), and the first valve (13) is loaded or can be loaded into a closed base position. A through-opening (12a, 12b) which connects the upper displacement chamber (8) to the lower displacement chamber (9) with the interposition of a second valve (14) is arranged in or on the piston (6), and the lower displacement chamber (9) transitions into the outlet opening (5) via an outlet channel (16). When the piston (6) is lowered as the result of a negative pressure in the upper displacement chamber (8), the first valve opens (for example against a spring force), and lubricant is suctioned out of the storage container into the upper displacement chamber (8), but the second valve (14) closes and lubricant is pushed out of the lower displacement chamber (9) into the outlet channel (16). When the piston (6) is raised, the first valve (13) closes, but the second valve (14) opens in the piston (6), and lubricant both flows from the upper displacement chamber (8) into the lower displacement chamber (9) and is pushed from the lower displacement chamber (9) into the outlet channel (16).

The invention relates to a lubricant dispenser comprising a storage container (1) filled with lubricant and a pump (2) which is connected to or can be connected to the storage container (1) and by means of which the lubricant can be pumped out of the storage container (1). The pump has a pump housing (3) with an inlet opening (4) and an outlet opening (5), a piston (6) which is movably guided in the pump housing (3) in a linear manner, and a drive (7) which acts on the piston (6). The pump housing (3) of the pump (2) is connected to or can be connected to the storage container (1), and the piston (6) can be raised or lowered cyclically by the drive (7) in order to pump a lubricant from the inlet opening (4) to the outlet opening (5). The lubricant dispenser is characterized in that the piston (6) is designed in a stepped manner with an upper piston surface (10) which delimits an upper displacement chamber (8) and a lower piston surface (11) which delimits a lower displacement chamber (9) and is reduced compared to the upper piston surface (10). The upper displacement chamber (8) adjoins the inlet opening (4) via a first valve (13), and the first valve (13) is loaded or can be loaded into a closed base position. A through-opening (12a, 12b) which connects the upper displacement chamber (8) to the lower displacement chamber (9) with the interposition of a second valve (14) is arranged in or on the piston (6), and the lower displacement chamber (9) transitions into the outlet opening (5) via an outlet channel (16). When the piston (6) is lowered as the result of a negative pressure in the upper displacement chamber (8), the first valve opens (for example against a spring force), and lubricant is suctioned out of the storage container into the upper displacement chamber (8), but the second valve (14) closes and lubricant is pushed out of the lower displacement chamber (9) into the outlet channel (16). When the piston (6) is raised, the first valve (13) closes, but the second valve (14) opens in the piston (6), and lubricant both flows from the upper displacement chamber (8) into the lower displacement chamber (9) and is pushed from the lower displacement chamber (9) into the outlet channel (16).

A method controls the start-up of an oil pump of a gearbox by a brushless electric motor that has no position sensor. The stator coils are powered from the off mode in a constant-current open-loop control sequence until the pump reaches a speed threshold at which speed regulation switches over to closed-loop control on a setpoint corresponding to the lubrication flow rate required to ensure the reliability of the gearbox, but without in so doing exceeding a current threshold indicative of pump seizure, at which point motor control switches back over to the constant-current open-loop control sequence. The open-loop current setpoint is higher than the threshold for switching over to closed-loop control so that in the open-loop control mode the motor torque available at the pump is higher than in the closed-loop control mode.

A pump system for supplying lubricant to components of a wind turbine comprises: a pump for pumping lubricant through a fluid circuit of the wind turbine; a drive means for driving the pump; and, a gearbox arrangement arranged to couple the drive means to the pump. The gearbox arrangement comprises a rotatable input shaft configured to be driven by the drive means and a rotatable output shaft configured to drive the pump. The input shaft is rotatable in a first direction of rotation and a second direction of rotation when driven by the drive means. The output shaft is rotatable in the first direction of rotation, and the speed of rotation of the output shaft is determined by an operational mode of the gearbox arrangement. In a first mode of operation, when the input shaft rotates in the first direction of rotation at a first speed of rotation, the gearbox arrangement is configured to drive the output shaft to rotate also in the first direction of rotation at the first speed of rotation. In a second mode of operation, when the input shaft rotates in the second direction of rotation at the first speed of rotation, the gearbox arrangement is configured to drive the output shaft to rotate in the first direction of rotation at a second speed of rotation.