Electric Motor Speed Control Lever with Integrated Adjustment Buttons
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Solution Overview
Problem
Self-propelled electric lawn movers require drivers to hold levers in unstable, inaccurate intermediate positions to control speed, leading to driver fatigue and difficulty in maintaining constant speeds.
Innovation Solution
A speed control device with a control system and unit that allows drivers to adjust the maximum setpoint speed without releasing the lever, using accessible adjustment means, such as buttons or knobs, allowing speed control with one hand while maintaining the lever, reducing muscle fatigue and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the driver holds the lever in an intermediate position to control speed, then the vehicle speed can be adjusted, but the driver experiences fatigue and the control becomes unstable and inaccurate
Solution Approach 1:
The control system is segmented into two independent functions: a lever for selecting speed range (0-5 km/h or 5-10 km/h) and separate adjustment means (buttons) for fine-tuning the maximum speed value. This segmentation allows the driver to maintain a stable lever position while adjusting speed, eliminating the need to hold unstable intermediate positions.
Solution Approach 2:
The adjustment buttons act as an intermediary mechanism between the driver's intent and the actual speed control. The driver presses buttons to adjust the maximum speed value without moving the lever from its stable position, mediating the speed adjustment function separately from the lever positioning function.
2Speed
If the driver moves the lever to intermediate positions for speed control, then speed variation is possible, but the control accuracy decreases
Solution Approach 1:
The control system separates speed range selection (lever) from speed value adjustment (buttons). The lever provides coarse control by selecting between predefined ranges, while the buttons provide fine control by adjusting the maximum speed value in 0.5 km/h increments, achieving both speed variation and high precision.
Solution Approach 2:
The system dynamically adjusts the maximum speed value based on button presses while the lever remains in a fixed position. This dynamic adjustment of the speed parameter independent of lever position enables precise speed control without compromising stability.
3Device complexity
If adjustment means are placed away from the control lever, then the control system is simpler, but the driver must release the lever to adjust speed
Solution Approach 1:
The adjustment buttons are merged with the control lever assembly, positioned on the same handlebar within easy reach of the driver's hand. This spatial merging allows simultaneous access to both lever control and speed adjustment without requiring the driver to release the lever, combining multiple functions in a compact configuration.
4Device complexity
If mechanical cables are used for speed control, then the control system is mechanically simple, but wear on control components increases
Solution Approach 1:
The patent replaces mechanical cable-based speed control with an electronic control system. The control unit receives signals from the lever position sensor and button inputs, then electronically controls the propulsion machine's speed. This substitution eliminates mechanical cables and associated wear, improving reliability while maintaining control functionality.
Data Source
AI summary
The invention relates to a control device (2) for controlling a vehicle having an electric motor (1), the control device comprising a control system (21, 22, 23) provided with one or more levers movable between a minimum control position and a maximum control position, and a control unit (3) for controlling the motor. Said control unit (3) includes acquisition means (31) for acquiring a signal representative of the position of said control system, determination means (32) for determining a setpoint speed value corresponding to said acquired signal, as a function of a maximum setpoint speed value associated with the maximum control position, and control means (33) for controlling the motor as a function of the determined setpoint speed. Said control device has adjustment means (34) arranged with the lever(s) of the system to enable the maximum setpoint speed value to be adjusted without taking a hand away from the lever(s). The invention also provides a corresponding vehicle.