Combination Square Dovetail Locking Mechanism
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Solution Overview
Problem
Existing combination squares face challenges such as cumbersome thumbscrew operation, inaccurate locking due to random clamping forces, and difficulty in handling irregular workpiece surfaces, particularly radiused or chamfered surfaces.
Innovation Solution
A combination square design featuring a blade and body with a dovetailed locking mechanism, allowing for easy adjustment and secure locking, and a removable extension bracket for use on irregular surfaces, enabling precise angle measurement and marking on both standard and irregular surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a transverse rib with thumbscrew is used to lock the blade, then the blade position can be locked, but the operation becomes cumbersome and time-consuming
Solution Approach 1:
The patent replaces the traditional thumbscrew mechanical locking system with a spring-loaded detent mechanism. The spring automatically engages the detent with the blade's locking surface, providing reliable locking without requiring manual thumbscrew operation. This substitution eliminates the cumbersome tightening/loosening action while maintaining secure blade positioning.
Solution Approach 2:
The spring-loaded detent mechanism is designed to automatically engage and disengage with the blade's locking surface as the blade moves into or out of position. The spring force automatically maintains the locked state without requiring continuous manual intervention, allowing the system to serve itself in maintaining blade position.
2Reliability
If a transverse rib is used to lock the blade, then the blade position can be secured, but the blade does not slide well and may slip free
Solution Approach 1:
The patent applies local quality by creating a specific geometric relationship between the detent's engagement surface and the blade's locking surface. The angled surfaces are designed to provide gradual engagement during sliding, reducing resistance, while the final engagement position provides positive locking to prevent slipping. This localized geometric design solves both the sliding and locking requirements.
Solution Approach 2:
The spring-loaded detent mechanism is designed to be dynamic rather than static. The spring allows the detent to flex and adjust during blade movement, providing smooth engagement and disengagement. This dynamic characteristic reduces sliding resistance while maintaining reliable locking when the blade reaches its target position.
3Ease of operation
If the body clamps directly against the blade face, then locking is achieved, but the random clamping area reduces measurement accuracy
Solution Approach 1:
The patent extracts the clamping function from the main body and relocates it to a separate spring-loaded detent component. This detent engages with a specific localized feature on the blade rather than the body clamping against the entire blade face. By separating the locking function from the measuring surfaces, the patent eliminates the source of measurement error while maintaining simple operation.
Solution Approach 2:
The detent mechanism serves as an intermediary between the body and the blade. Instead of the body directly clamping the blade face, the detent mediates the locking action by engaging with a dedicated locking surface on the blade. This intermediary component isolates the measuring surfaces from clamping forces, preserving measurement precision.
4Adaptability or versatility
If smooth surfaces at 90° and 45° are used for angle construction, then angle checking is enabled, but the tool cannot accommodate irregular surfaces like radiused or chamfered edges
Solution Approach 1:
The patent makes the combination square body universal by providing multiple angled surfaces (90°, 45°, and other configurations) that can accommodate various workpiece geometries. The blade can be positioned at different angles relative to the body, allowing the tool to work with flat edges, radiused corners, chamfered surfaces, and other irregular geometries while maintaining measurement stability through the secure detent locking mechanism.
Data Source
AI summary
A combination square includes a blade, a body, and a lock. The body comprises a slot adapted to receive the blade therein and permit sliding translation of the blade parallel to the longitudinal axis of the blade, allowing the position of the blade to be adjusted relative to the body. The lock is adapted to lock the position of the blade relative to the body in a locked configuration and to allow adjustment of the position of the blade relative to the body in a released configuration. The combination square also comprises a removable extension bracket being wider than and removable from the body and comprising one or more working surfaces.