Power Tool Trigger Mechanism Using Force Sensing Resistor

The patent replaces the traditional mechanical trigger system with a sensor-based detection system. Instead of using a mechanical plunger and switch that require movement and clearance, the invention uses a sensor (such as a force sensing resistor, capacitive sensor, or optical sensor) to detect when the trigger is actuated. This substitution eliminates the need for mechanical movement components, significantly reducing the space required in the housing while maintaining full trigger actuation functionality.

The patent extracts and removes the unnecessary mechanical components (plunger, spring, mechanical switch) from the trigger mechanism. By taking out these components that require space and create clearance gaps, the design achieves a more compact trigger assembly that fits within the housing without creating pathways for contaminant ingress.

The patent eliminates mechanical displacement by replacing the mechanical trigger system with a sensor-based system. The sensor detects trigger actuation through changes in physical quantities (force, capacitance, optical properties) without requiring the trigger to physically displace or create clearance gaps. This substitution directly addresses both the operational requirement and the contamination prevention requirement simultaneously.

The patent may employ flexible or sealed membranes that allow sensor detection while maintaining a sealed barrier against contaminants. These thin film structures can transmit mechanical forces or physical changes to the sensor while preventing water, dirt, and other contaminants from penetrating into the housing, thus allowing trigger actuation without creating contamination pathways.

The patent replaces the mechanical actuation system with a sensor-based detection system. The trigger contact body remains fixed relative to the housing, and actuation is detected through sensor measurements (force application, capacitance change, or optical variation) rather than mechanical movement. This substitution maintains full operational functionality while eliminating wear associated with mechanical movement, thereby extending trigger lifespan.

The patent introduces a sensor as an intermediary between the trigger contact body and the control system. This intermediary detects the actuation state through physical field changes (force, electrical field, optical field) without requiring direct mechanical contact or movement between the trigger and the actuation mechanism, thus allowing the trigger to remain fixed while still enabling reliable actuation detection.