Inertial Sensor Trigger Mechanism for Wear-Resistant Precision Control
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Solution Overview
Problem
Existing trigger mechanisms in handheld tools, such as potentiometers, face issues with wear-out due to physical contact and lack of sufficient granularity for precise control, leading to limited lifetime and binary control options.
Innovation Solution
A dual-sensor apparatus using inertial sensors, where a first sensor is fixed and a second sensor rotates relative to the first, maintaining an askew orientation, to convert linear trigger depression into rotational motion, enabling precise control through differential motion detection and mitigating common-mode noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If potentiometers are used for trigger control, then binary or limited control is achieved, but wear-out occurs due to physical contact and lifetime is limited
Solution Approach 1:
The patent replaces the mechanical potentiometer system with an inertial sensor-based detection system. Instead of using physical contacts that wear out, the system uses accelerometers to detect the trigger member's position and motion through inertial measurements, eliminating mechanical wear while maintaining control functionality
Solution Approach 2:
The patent introduces inertial sensors as an intermediary between the trigger member and the control system. The sensors detect motion and position indirectly through acceleration measurements rather than direct electrical contact, serving as a mediator that eliminates wear while preserving control capability
2Reliability
If contactless trigger mechanisms are used, then wear is reduced, but control granularity and precision are insufficient
Solution Approach 1:
The patent uses multiple inertial sensors (at least two accelerometers) to segment the detection function. By combining measurements from multiple sensors oriented in different directions, the system achieves precise three-dimensional position and motion detection without mechanical contact
Solution Approach 2:
The patent transitions from one-dimensional or two-dimensional control detection to three-dimensional detection using inertial sensors. The accelerometers measure acceleration vectors in multiple dimensions, allowing precise determination of trigger member position and motion state through spatial vector analysis
3Reliability
If inertial sensors are used for trigger detection, then wear-resistant contactless control is achieved, but device complexity increases
Solution Approach 1:
The inertial sensor system serves multiple functions simultaneously: it detects trigger member position, determines motion state, calculates velocity and acceleration, and provides wear-resistant contactless operation. This multi-functionality reduces the need for separate mechanical components, offsetting the added sensor complexity
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
Provides wear-resistant, contactless control with enhanced precision and granularity, allowing nuanced user inputs for varied tool operation without relying on potentiometers.
Implementation Method 1
a first inertial sensor, such as an accelerometer, is affixed to at least one of the trigger member or the housing and provides motion data along at least a first axis and a second axis
Data Source
AI summary
An apparatus for providing variable end user control of a handheld tool function includes a trigger member arranged for travel during user depression relative to a tool body. A first inertial sensor, affixed to either the trigger member or body, maintains a fixed orientation and provides motion data along at least first and second axes. A second inertial sensor, arranged on the trigger member or body, rotates relative to the first inertial sensor during trigger depression, with the rotation amount varying based on depression amount. Throughout its entire range of rotation, the second inertial sensor rotates about a third axis that remains askew with respect to both the first and second axes of the first inertial sensor.