Power Tool Directional Trigger Locking Against Accidental Unlocking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electric screwdrivers suffer from unreliable trigger locking, leading to accidental shutdowns and reduced work efficiency and quality due to easy accidental unlocking of the trigger.
Innovation Solution
A power tool design featuring a directional assembly that locks the switch assembly at the startup position, using a directional member with a protrusion and groove mechanism to prevent accidental unlocking, combined with an elastic member for reliable trigger retention and a directional member toggleable between forward, reverse, and locking positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a simple trigger locking mechanism is used, then the device complexity is reduced, but the reliability of the trigger lock is poor leading to accidental unlocking
Solution Approach 1:
The locking mechanism uses asymmetric geometry where the directional member has a protrusion that fits into a groove on the trigger only in the locked position. The groove has a specific shape that allows the protrusion to engage securely in the locked state but prevents engagement in other positions, providing reliable locking through asymmetric geometric constraints rather than complex mechanical components.
Solution Approach 2:
The solution moves from a one-dimensional linear locking approach to a two-dimensional angular positioning approach. The directional member rotates to different angular positions (forward rotation position, reverse rotation position, locking position) and the locking occurs when the protrusion aligns with the groove in a specific angular orientation, adding a rotational dimension to the locking mechanism.
2Ease of operation
If the trigger is easily accessible for operation, then the ease of operation is improved, but the trigger is easy to touch by accident causing unintended shutdown
Solution Approach 1:
The directional member is positioned in the locking position before the trigger operation begins. The protrusion is already engaged with the groove, pre-establishing the locked state. This preliminary locking action prevents accidental activation during subsequent trigger operations, while still allowing intentional unlocking by rotating the directional member to disengage the protrusion from the groove.
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
Enhances the reliability of the electric motor's rotation process, improving work efficiency and quality by maintaining the power tool in a consistent operating state despite accidental touches or vibrations.
Implementation Method 1
a first elastic member disposed between the trigger and the housing, where when the directional member is at the forward rotation position and the reverse rotation position, the first elastic member causes the trigger to return to the shutdown position
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A power tool includes a housing, an electric motor, a switch assembly, and a directional assembly. The electric motor is disposed at least partially in the housing and includes a rotating shaft rotatable about a first axis. The switch assembly is for a user to operate to switch between a startup position and a shutdown position, where the switch assembly at the startup position sends a startup signal to the electric motor, and the switch assembly at the shutdown position sends a shutdown signal to the electric motor. The directional assembly is for the user to operate to control a rotation direction of the electric motor. The directional assembly is further configured to mate with the switch assembly to lock the switch assembly at the startup position. When the directional assembly is operated to be disengaged from the switch assembly to unlock the switch assembly, the switch assembly switches to the shutdown position.