Slider Locking Pawl Chamfered Ridge Design
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Solution Overview
Problem
Conventional sliders with automatic stop mechanisms using locking pawls often fail to achieve sufficient spring force and may cause cracks in caulking portions due to local stress, limiting the travel and durability of the locking pawl.
Innovation Solution
The slider design incorporates chamfered ridges on the locking pawl to prevent local stress on caulking portions, allowing smoother sliding and full expression of spring force, with chamfered profiles on contact surfaces to reduce the likelihood of the locking pawl being caught and to enhance durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the locking pawl is caulked by inwardly bending the caulking portions, then the locking pawl is fixed in position, but the ridge is caught by contact surfaces with the caulking portions causing insufficient spring force expression and potential cracks
Solution Approach 1:
The patent applies local quality by providing chamfer portions only at specific ridge locations of the locking pawl that contact the caulking portions, rather than modifying the entire structure. This localized chamfering reduces stress concentration precisely where it occurs during caulking, preventing cracks while maintaining the overall structural integrity and spring force of the locking pawl.
Solution Approach 2:
The chamfer portions are provided in advance on the locking pawl before the caulking operation. This preliminary action prepares the contact surfaces to distribute stress evenly during the subsequent caulking process, preventing the ridge from being caught by the contact surfaces and ensuring smooth deformation of the caulking portions without generating harmful local stress.
2Reliability
If the locking pawl is held before fully descended to predetermined position, then the slider cannot maintain stop position, but the chamfered design allows full expression of spring force
Solution Approach 1:
The chamfer portions are strategically placed only at the ridge locations that contact the caulking portions during the locking operation. This localized modification smooths the critical contact points where the locking pawl engages with the caulking portions, ensuring smooth travel and full spring force expression without requiring modifications to the entire locking mechanism structure.
3Duration of action of stationary object
If the caulking portions are subjected to local stress, then cracks may originate and durability is reduced, but the chamfered ridge prevents local stress application
Solution Approach 1:
The chamfer portions are applied locally at the ridge contact surfaces with the caulking portions, creating a stress-distributing geometry precisely where local stress concentration occurs during caulking. This localized geometric modification transforms the contact from a sharp ridge to a gradual slope, distributing the deformation stress across a larger area and preventing crack initiation.
Solution Approach 2:
The chamfer portions serve as a preliminary stress-distributing feature that cushions the impact of local stress during the caulking operation. By providing this geometric cushioning in advance on the locking pawl ridges, the patent prevents the concentration of harmful stresses that would otherwise lead to crack formation and reduced durability of the caulking portions.
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 chamfered design improves the reliability of the automatic stop mechanism by ensuring the locking pawl can fully express its spring force and reduces the likelihood of cracks in the caulking portions, enhancing the slider's durability and stability.
Implementation Method 1
a locking pawl assembled in the slider keeps the slider at a stop position as energized by the spring force
Implementation Method 2
a ridge of the locking pawl, which is brought into contact with the caulking portion, is provided with a chamfer portion
Data Source
AI summary
A slider for slide fasteners having a slider body with the leading end of the upper and lower plates connected by a connecting bar and a y-shaped element guiding path disposed between the upper and lower plates, a pull with one end rotatably held on the upper plate, and a stopping hook disposed on the upper plate and having a hook at one end; the upper plate having an insertion groove for inserting the stopping hook, a locking part for locking the other end of the stopping hook, and a hook eyelet drilled so that the hook can be inserted; and the stopping hook is disposed so that by tilting/erecting manipulations of the pull, the hook can be inserted/withdrawn from the element guiding path through the hook eyelet; wherein the corners of the stopping hook that contact the locking part, at least during locking operation, form beveled parts.