Method and device for an overload detection in hand-guided power tools
First Claim
1. A method for detecting an overload situation in a battery-powered hand-guided power tool (10) equipped with an electric motor (12) and a DC battery pack (14) for supplying an operating current (IB) to the electric motor (12), in particular for a battery-powered hand-guided power tool (10), in which the operating current (IB) of the electric motor (12) is determined,wherein a difference (ID) between the value of the operating current (IB) and at least one stored current value (IG) is determined, in association with a maximum set point duration (ta), which maximum set point duration (ta) defines a maximum duration of said overload situation by taking into account an operating temperature (T0) of the hand-guided power tool (10), particularly at a moment at which the tool is switched on, and based on the difference (ID), a conclusion is drawn as to whether a thermal overloading of the power tool (10) is occurring.
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Accused Products
Abstract
The invention relates to a method for detecting an overload in an electric hand tool (10) comprising an electric motor (12), in particular a battery-driven electric hand tool (10). According to the invention, an operating current (iB) of the electric motor (12) is determined, the difference (ID) between the value of the operating current (IB) and at least one stored current value (IG) is determined and a thermal overload of the electric hand tool (10) is deduced from said difference (ID). The invention also relates to a corresponding monitoring device (22).
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Citations
23 Claims
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1. A method for detecting an overload situation in a battery-powered hand-guided power tool (10) equipped with an electric motor (12) and a DC battery pack (14) for supplying an operating current (IB) to the electric motor (12), in particular for a battery-powered hand-guided power tool (10), in which the operating current (IB) of the electric motor (12) is determined,
wherein a difference (ID) between the value of the operating current (IB) and at least one stored current value (IG) is determined, in association with a maximum set point duration (ta), which maximum set point duration (ta) defines a maximum duration of said overload situation by taking into account an operating temperature (T0) of the hand-guided power tool (10), particularly at a moment at which the tool is switched on, and based on the difference (ID), a conclusion is drawn as to whether a thermal overloading of the power tool (10) is occurring.
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11. A monitoring device (22) for detecting an overload situation in a battery-powered hand-guided power tool (10) equipped with an electric motor (12) and a DC battery pack (14) for supplying an operating current (IB) to the electric motor (12), particularly a battery-powered hand-guided power tool (10), which monitoring device (22) has a current measuring device (20) that determines the operating current (IB) of the electric motor (12),
wherein the monitoring device (22) also has a logic device (28) that calculates a difference (ID) between the operating current (IB) and at least one stored current value (IG), in association with a maximum set point duration (ta), which maximum set point duration (ta) defines a maximum duration of said overload situation by taking into account an operating temperature (T0) of the hand-guided power tool (10), particularly at a moment at which the tool is switched on, and based on the resulting difference (ID), determines whether a thermal overload is occurring.
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13. A method for detecting an overload situation in a battery-powered hand-guided power tool (10) equipped with an electric motor (12) and a DC battery pack (14) for supplying an operating current (IB) to the electric motor (12), in particular for a battery-powered hand-guided power tool (10), in which the operating current (IB) of the electric motor (12) is determined,
wherein a difference (ID) between the value of the operating current (IB) and at least one stored current value (IG) is determined and based on this difference (ID), a conclusion is drawn as to whether a thermal overloading of the power tool (10) is occurring, which thermal overloading is associated with a maximum set point duration (ta), and wherein the association of thermal overloading and the maximum set point duration (ta) is stored in the form of a characteristic curve (30).
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23. A monitoring device (22) for detecting an overload situation in a battery-powered hand-guided power tool (10) equipped with an electric motor (12) and a DC battery pack (14) for supplying an operating current (IB) to the electric motor (12), particularly a battery-powered hand-guided power tool (10), which monitoring device (22) has a current measuring device (20) that determines the operating current (IB) of the electric motor (12),
wherein the monitoring device (22) also has a logic device (28) that calculates a difference (ID) between the operating current (IB) and at least one stored current value (IG) and based on the result, determines whether a thermal overload is occurring, which thermal overload is associated with a maximum set point duration (ta), and wherein the association of thermal overload and the maximum set point duration (ta) is stored in the form of a characteristic curve (30).
Specification