Ratchet Wrench Handle Switch Mechanism Preventing Unintended Operation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional ratchet wrench handles suffer from unintended switch operations due to oscillation of engaging claws, leading to incorrect engagement between positive and reverse rotation ratchet teeth, and require enhanced coil spring flexibility, which is limited by the handle's size, resulting in reduced torque and increased size.
Innovation Solution
A ratchet wrench handle design featuring separate positive and reverse rotation claws on the operation piece, with a cam edge and pressing pin mechanism, and a switch member that prevents unintended switching by using a coil spring to bias the pressing pin, allowing for smaller handle head size while maintaining torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single member is used to form both engaging claws and switch member, then device complexity is reduced, but reliability deteriorates due to unintended switch operation from claw oscillation
Solution Approach 1:
The invention divides the single member into two separate components: the operation piece that holds the engaging claws, and the switch member that controls claw selection. This segmentation isolates the claws from the switching mechanism, preventing unintended switch operations caused by claw oscillation during ratchet teeth engagement.
2Reliability
If coil spring flexibility is enhanced to prevent unintended switching, then switch operation reliability improves, but handle head size increases due to limited space
Solution Approach 1:
The invention relocates the switching axis from a conventional position to a location on the extended line between the rotation member axis and the operation piece axis. This dimensional repositioning allows the switch member to effectively control claw engagement while using a standard coil spring, avoiding the need for enhanced spring flexibility that would increase handle head size.
3Force
If multiple operation claws are provided to disperse torque, then torque distribution improves, but handle head size increases
Solution Approach 1:
The invention positions the multiple operation claws asymmetrically on the operation piece, with each claw oriented to engage with specific ratchet teeth. This asymmetric arrangement allows effective torque dispersion across multiple claws while maintaining a compact handle head size, as the claws are optimally positioned rather than uniformly distributed.
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
Prevents unintended switch operations and allows for a smaller handle head while maintaining equivalent torque, as the operation claws engage and disengage correctly, dispersing torque and reducing ratchet teeth size.
Implementation Method 1
a distal end of the pressing pin pressurely contacts with the cam edge by way of a biasing force of a spring
Data Source
AI summary
In a ratchet wrench handle, an operation piece is swingably supported by an axis in a handle head. Positive and reverse rotation claws are disposed on one and the other portions of a distal end surface of an operation piece. The operation piece is provided with a cam edge at its backward end surface. A pressing pin is provided in a switch member such that the pressing pin can freely move into and out of the switch member. The distal end of the pressing pin pressurely contacts with the cam edge through a force of a spring. The switch member is located on a line extended from an imaginary straight line running between the rotation axis of the rotation member and the axis of the operation piece.