Conductive Elastomer Trigger Switch for Compact Variable Speed Control
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Solution Overview
Problem
Existing power tools face challenges in achieving compactness and efficiency in their trigger assemblies due to the need for more compact and efficient designs that meet modern power tool size requirements.
Innovation Solution
A trigger assembly utilizing a conductive elastomer member with a non-planar surface mechanically coupled to a trigger member, which varies motor speed based on the amount of surface area contact with conductive tracks on a circuit board, replicating the function of a potentiometer for variable speed control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a traditional potentiometer-based trigger switch is used, then variable speed control is achieved, but the size and complexity of the trigger assembly increases
Solution Approach 1:
The patent replaces the traditional mechanical potentiometer system with a conductive elastomer that deforms under compression to change electrical conductivity. This substitution eliminates complex mechanical components while achieving the same variable speed control function through material property changes, directly reducing trigger assembly size.
Solution Approach 2:
The invention changes the physical state of the elastomer from rigid to compliant, allowing it to deform and change electrical conductivity based on compression. This parameter change enables the elastomer to replace traditional mechanical variable resistors, achieving compact variable speed control without increasing assembly size.
2Volume of moving object
If more compact trigger assemblies are implemented, then size requirements are met, but sealing against environmental ingress becomes more difficult
Solution Approach 1:
The patent employs the conductive elastomer as both a functional component and a sealing element. The elastomer's flexible nature allows it to conform to housing surfaces and maintain sealing integrity even in compact configurations, preventing environmental ingress while maintaining reduced size.
Solution Approach 2:
The invention uses composite material properties of the elastomer, combining electrical conductivity with elastic deformation and sealing capabilities. This multi-functional material approach allows the trigger assembly to achieve compact size while maintaining environmental protection through the elastomer's inherent sealing properties.
3Volume of moving object
If a conductive elastomer is used instead of a potentiometer, then the trigger assembly size is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent utilizes the elastomer's ability to change electrical parameters (conductivity) in response to mechanical deformation. This parameter change approach allows for tolerance compensation, where variations in manufacturing dimensions are offset by the elastomer's nonlinear conductivity response, reducing the impact of manufacturing precision requirements.
Solution Approach 2:
The elastomer inherently provides its own calibration through its material properties. The nonlinear conductivity-deformation relationship serves as a built-in characteristic that compensates for manufacturing variations, eliminating the need for complex calibration procedures and reducing manufacturing precision requirements.
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
The conductive elastomer member provides a compact and efficient variable-speed detection mechanism, reducing size and enhancing conductivity, suitable for high-power density applications while offering improved sealing against environmental ingress.
Implementation Method 1
the elastomer member comprises semi-conductive elastically-deformable material
Implementation Method 2
the elastomer member includes an electrically-conductive non-planar surface
Data Source
AI summary
Systems, methods and apparatuses provide for technology that includes a motor, a trigger assembly including a trigger member and an elastomer member mechanically coupled to the trigger member and moveable along a movement axis, wherein the elastomer member includes an electrically-conductive non-planar surface, a controller configured to operate the motor, and a circuit board oriented substantially perpendicularly to the movement axis, the circuit board including a plurality of conductive tracks facing the non-planar surface coupled to a resistor divider, and wherein controller is configured to vary a speed of the motor based on a number of the plurality of conductive tracks contacted by the non-planar surface of the elastomer member. The elastomer member may include a non-planar surface having a conductive central region, a conductive peripheral region and an insulative region positioned between the conductive central region and the conductive peripheral region.