Magnetic Return Mechanism for Power Tool Trigger
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Solution Overview
Problem
Conventional motorized rotating tools with return springs require significant operator force to activate and maintain, leading to fatigue, musculoskeletal disorders, and safety issues due to increased effort and spring wear, necessitating frequent maintenance.
Innovation Solution
Implementing magnetic attraction means that exert a decreasing return force as the actuating means move from deactivation to activation positions, reducing the effort required to maintain tool operation and extending tool lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a compression spring is used as return means, then the trigger is returned quickly to deactivation position, but the operator must exert large force to activate and maintain the tool
Solution Approach 1:
The patent replaces the compression spring (mechanical elastic element) with a magnetic field-based return mechanism. The magnetic field exerts a force on the actuating means that is always directed toward the deactivation position, eliminating the need for operator force to maintain activation while providing controlled return motion.
Solution Approach 2:
The patent changes the physical parameter of the return force from elastic (spring) to magnetic. The magnetic force parameter allows for a different force-distance relationship where the force is strongest at greater distances and decreases as the actuating means approaches the deactivation position, providing smooth return without requiring large activation forces.
2Reliability
If a compression spring is used as return means, then the trigger returns automatically, but the spring wears out reducing reliability
Solution Approach 1:
The patent replaces the mechanical compression spring with a magnetic field generation system. Magnetic fields do not suffer from mechanical wear like springs do, as they are generated by electromagnetic coils or permanent magnets. This substitution eliminates wear-related degradation and extends the service life of the return mechanism while maintaining reliable trigger return functionality.
3Reliability
If large force is required on the trigger, then the tool activates reliably, but the operator experiences fatigue and poor posture
Solution Approach 1:
The patent replaces the spring-based mechanical resistance with a magnetic field-based force system. The magnetic force naturally provides strong restoring force when the actuating means is away from the deactivation position, ensuring reliable activation, while requiring minimal force to maintain the activated position, thereby improving operator comfort and reducing fatigue during prolonged use.
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 solution reduces operator fatigue, minimizes the risk of musculoskeletal disorders, enhances safety, and lowers maintenance costs by providing a consistent and durable return mechanism.
Implementation Method 1
magnetic attraction means which exert on the actuating means a return force, the value of which decreases as the actuating means are moved from their deactivation position to their activation position
Data Source
Figure 1~3
Figure 4~5
AI summary
The tool (1) has a terminal element (3) mounted to move at an end of a body (2), where the body houses a motor unit e.g. electric motor, connected to the element. A trigger (4) moves between activation position, in which the motor unit moves and drives the element and deactivation position, in which the unit is stopped to prevent movement of the element. A magnet (7) returns the trigger to the deactivation position and exerts return force on the trigger, where value of the force decreases as the trigger is moved from the deactivation position to the activation position.