Trigger Mechanism With Adjustable Rearmost Position And Locking
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Solution Overview
Problem
Existing trigger mechanisms for electric power tools lack convenience in operation, particularly in adjusting the trigger's rearmost position and locking functionality, which limits user experience and control over the tool's speed and torque.
Innovation Solution
A trigger mechanism with a housing, a resiliently biased trigger, an adjustable rearmost position, a locking device with movable prongs, and a screw-threaded shaft for precise adjustment, allowing for convenient locking and unlocking of the trigger at the rearmost position, enhancing user control over the tool's speed and torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed rearmost position of the trigger is used, then the structure is simple, but the user cannot adjust the trigger position to control speed and torque
Solution Approach 1:
The adjuster mechanism is nested within the housing structure. The adjuster (130) includes a shaft (132) and stop (133) that are integrated into the housing (110), with the stop being receivable within a recess (113) in the trigger stem (124). This nesting approach allows adjustment functionality without adding external complexity.
Solution Approach 2:
The stop (133) acts as an intermediary element between the adjuster mechanism and the trigger (120). The stop is receivable within the recess in the trigger stem and engages with the trigger to limit its movement, providing a simple yet effective means of position control without direct mechanical linkage complexity.
2Reliability
If a locking device with multiple prongs is used to lock the trigger at different positions, then the locking capability is improved, but the device complexity increases
Solution Approach 1:
The locking device (140) is segmented into two functional members: a first member (141) that moves linearly in opposite directions, and a second member (144) that pivots to engage the trigger. This segmentation allows the locking function to be achieved through coordinated simple movements rather than a single complex mechanism.
Solution Approach 2:
The locking device uses dynamic movement of its members to achieve locking. The first member (141) moves linearly to position the second member, which then pivots dynamically to engage the trigger at the desired position. This dynamic approach allows reliable locking without requiring multiple fixed prongs or complex mechanisms.
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 mechanism provides improved user convenience by allowing adjustable trigger positioning and secure locking, enabling precise control over the electric motor's speed and torque, enhancing operational efficiency and user experience.
Implementation Method 1
the trigger being resiliently biased by a spring to return towards the foremost position
Implementation Method 2
the locking device is resiliently biased by a spring to stay normally in a central position
Data Source
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AI summary
A trigger mechanism for an electric power tool, comprises a spring-loaded trigger movable between an foremost position and an rearmost position, an adjuster for adjusting the rearmost position, an electrical switch arranged for closing by the trigger while the trigger is in an intermediate position, and a variable resistor arranged for operation by the trigger while the trigger is in an intermediate position to provide a resistance of a valve dependent upon the position of the trigger. A locking device is included for locking the trigger near the rearmost position, which is movable in opposite directions and arranged to lock the trigger near the rearmost position when the locking device is moved in either one of said opposite directions.