Hand-held electrically powered cut-off tool with a kickback mitigation function
AssigneeHusqvarna AB
InventorsMagnus Rosén, Victor Johansson, David Dufke, Johan Berg
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Abstract
A hand-held electrically powered cut-off tool (100) for cutting concrete and stone by a rotatable cutting disc (105), the cut-off tool (100) comprising an electric motor (130) arranged to be controlled by a control unit (110) via a motor control interface (120), wherein the control unit (110) is arranged to obtain data indicative of an angular velocity of the cutting disc (105), and to detect a kickback condition based on a decrease in angular velocity, and wherein the control unit (110) is arranged to electromagnetically brake the electric motor (130) in response to detecting a kickback condition.
Claims20
A hand-held electrically powered cut-off tool for cutting concrete and stone by a rotatable cutting disc, the cut-off tool comprising an electric motor arranged to be controlled by a control unit via a motor control interface,
- wherein the control unit is arranged to obtain data indicative of an angular velocity of the cutting disc, and to detect a kickback condition based on a decrease in angular velocity,
- wherein the control unit is arranged to control an electromagnetic braking of the electric motor in response to detecting a kickback condition, and
- wherein the control unit is arranged to actively regulate an energy outtake from the electric motor over the control interface during the electromagnetic braking.
A method in a control unit for mitigating kickback in a hand-held electrically powered cut-off tool arranged for cutting concrete and stone by a rotatable cutting disc, wherein the cut-off tool comprises an electric motor arranged to be controlled by the control unit via a motor control interface, the method comprising
- obtaining data indicative of an angular velocity of the cutting disc,
- detecting a kickback condition based on a decrease in angular velocity, and
- controlling electromagnetic braking of the electric motor in response to detecting a kickback condition, wherein the controlling comprises actively regulating an energy outtake from the electric motor over the control interface during the electromagnetic braking.
A hand-held electrically powered cut-off tool for cutting concrete and stone by a rotatable cutting disc, the cut-off tool comprising an electric motor arranged to be controlled by a control unit via a motor control interface,
- wherein the control unit is arranged to determine an angular position of a rotor of the electric motor based on a current over the control interface, and to obtain data indicative of an angular velocity of the cutting disc based on a rate of change of the angular position of the rotor over time,
- wherein the control unit is arranged to detect a kickback condition based on a decrease in angular velocity of the cutting disc, and to control electromagnetic braking of the electric motor in response to detecting a kickback condition, and
- wherein the control unit is arranged to actively regulate an energy outtake from the electric motor over the control interface during the electromagnetic braking.
A hand-held electrically powered cut-off tool for cutting concrete and stone by a rotatable cutting disc, the cut-off tool comprising an electric motor arranged to be controlled by a control unit via a motor control interface,
- wherein the control unit is arranged to obtain data indicative of an angular velocity of the cutting disc, and to detect a kickback condition based on a decrease in angular velocity,
- wherein the control unit is arranged to control an electromagnetic braking of the electric motor in response to detecting a kickback condition,
- wherein the electrically powered cut-off tool comprises an energy dissipating module configured to dissipate energy from the electric motor during the electromagnetic braking.
Dependencies are inferred from the claim text.