Throttle Lever Control Electronics for Battery Tool Startup Losses
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Solution Overview
Problem
Portable, hand-held tools with battery-powered electric motors face challenges in providing sufficient drive power and extended operating time due to inefficient energy usage, with existing designs often resulting in high startup losses and reduced battery life.
Innovation Solution
The throttle lever is connected to an electrical actuator that provides a position-dependent output signal to control electronics, allowing the drive motor to receive energy only when the throttle is significantly depressed, minimizing startup losses by using a strong voltage signal and pulse-width modulation, and incorporating a mechanical switch for two-hand safety and overload protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the drive motor is activated with standard voltage signal, then the motor starts up, but high startup losses occur and battery charge is depleted quickly
Solution Approach 1:
The patent applies periodic action by using pulse-width modulation (PWM) to supply electrical energy to the drive motor in periodic pulses rather than continuous supply. The control electronics switch the power circuit on and off in a periodic manner, with the duty cycle adjusted according to the required power output. This periodic energy supply reduces startup losses by avoiding continuous high-current draw during motor acceleration, thereby extending battery operating time while still delivering sufficient peak power when needed.
2Power
If the battery pack provides sufficient drive power, then the tool operates effectively, but the operating time is reduced
Solution Approach 1:
The patent applies dynamics by implementing a dynamic control system that continuously adjusts the power delivery to the drive motor based on actual operational requirements. The control electronics monitor the throttle lever position and adjust the PWM duty cycle dynamically, delivering high power only when needed (during high-load operations) and reducing power delivery during low-load conditions. This dynamic power management allows the battery pack to provide sufficient drive power when required while significantly extending the overall operating time by avoiding wasteful continuous high-power consumption.
3Ease of operation
If the actuator has mechanical dead travel, then the switch position can be adjusted, but the motor starts abruptly with high starting speed causing energy losses
Solution Approach 1:
The patent applies mechanics substitution by replacing the traditional mechanical dead-travel actuator system with an electronically controlled throttle lever and PWM-based motor control. Instead of relying on mechanical dead travel to prevent accidental activation, the system uses electronic sensing of the throttle lever position combined with PWM control to gradually build up motor speed. This substitution eliminates the abrupt mechanical engagement that causes high starting losses, while maintaining ease of operation through the throttle lever's progressive activation mechanism.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enhances the efficiency of battery charge usage, reduces startup losses, and increases the operating time of battery-powered tools by ensuring energy is supplied only when needed, while ensuring operational safety through two-hand operation and overload protection.
Implementation Method 1
The throttle lever (32) of the implement (1) is connected to an electrical actuator (31)
Implementation Method 2
a drive motor (8) which is controlled by the control electronics (26)
Implementation Method 3
at least one mechanical switch is arranged in the power circuit of the control electronics (26), which switches the power circuit on and off
Data Source
Figure 1~2
Figure 3~5
Figure 6
AI summary
The invention relates to a battery-powered, handheld power tool such as a chainsaw or the like. Handles (4, 6) for carrying and guiding the power tool are provided on the tool housing (9). An electric drive motor (8) and an output shaft (14) for a cutting tool (11) are arranged in the tool housing (9), as well as a battery pack (15) for operating the power tool. One of the handles (4) has a control element (32) for controlling the drive motor (8), which is pivotable about a rotary axis (21) and acts on an electrical actuator (31). To enable the electric motor to start up quickly, the output signal of the electrical actuator (31) is fed to a control electronics unit (26) to which the battery pack (15) and the drive motor (8) are connected.The supplied electrical energy is measured by the control electronics (26) depending on the rotational position of the control element (32), whereby in a first angular range (35) of the swiveling control element (32) the measured electrical energy is "zero".