Slider Locking Pawl Positioning to Prevent Yarn Damage
Solution Overview
Problem
Conventional slide fastener sliders with automatic locking mechanisms often damage sewing yarns or fail to exert a sufficient locking function due to the small gap between locking pawls and fastener elements, leading to operational issues and frequent troubles.
Innovation Solution
A slide fastener slider design featuring a locking pawl integrated into the cover, which is inserted into a gap between fastener elements on the shoulder mouth side, allowing for secure engagement without damaging yarns, and a pull-tab mechanism that ensures smooth operation and long-term functionality by positioning the locking pawl within an excess space and using a tapered pull-tab guide to prevent contact with the pawl.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the locking pawl is inserted into the gap between fastener elements at the rear position, then the locking function can be exerted, but the gap is too small causing insufficient locking and potential yarn damage
Solution Approach 1:
The patent inverts the conventional approach by moving the locking pawl from the rear position to the front position of the slider. Instead of inserting the pawl into the narrow gap at the rear, the pawl now engages with fastener elements at the front where there is sufficient space, eliminating yarn damage while maintaining locking reliability
Solution Approach 2:
The patent changes the spatial dimension of locking pawl insertion from the rear gap (conventional approach) to the front region of the slider. This dimensional shift allows the pawl to engage with fastener elements in a location with adequate space, resolving the contradiction between achieving locking function and avoiding yarn damage
2Reliability
If the locking pawl is inserted into the small gap between fastener elements, then engagement is achieved, but the locking function cannot be exerted sufficiently
Solution Approach 1:
The patent reverses the conventional locking mechanism arrangement by positioning the locking pawl at the front of the slider instead of at the rear. This inversion allows the pawl to engage with fastener elements in a location with adequate spacing, ensuring sufficient locking function without relying on narrow gaps
3Ease of operation
If the pull-tab pivot shaft contacts the locking pawl during operation, then the locking mechanism may be activated, but smooth sliding is disrupted and operational troubles occur
Solution Approach 1:
The patent introduces a tapered guide surface as an intermediary element between the pull-tab pivot shaft and the locking pawl. This guide surface directs the pivot shaft's movement path, preventing direct contact with the locking pawl while maintaining operational smoothness and stability
Solution Approach 2:
The patent employs a tapered guide surface that beforehand directs and controls the movement of the pull-tab pivot shaft, preventing it from contacting the locking pawl during normal operation. This preemptive guidance mechanism eliminates operational disruptions before they can occur
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 solution enables effective locking without yarn damage, facilitates easy assembly using conventional equipment, ensures smooth sliding, and prevents foreign matter intrusion, resulting in a reliable and durable slider with improved performance.
Implementation Method 1
an elastic piece contacting a supporting portion provided in front attaching posts projects from a front end of a top wall of the cover
Data Source
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AI summary
The invention provides a slide fastener slider with an automatic locking device comprising: a pawl hole (22) in which a locking pawl (30) can be inserted is provided in a top surface of a body (1) of the slider; front attaching posts (10) and a rear attaching post (11) are provided in front of and in back of the pawl hole (22); a cover (7) comprises front engaged portions (32) which engage the front attaching posts(10) and rear engaged portions (33) which can move vertically within the rear attaching post (11); an elastic piece (31) having an elasticity is provided at a front end of a top wall (26) of the cover (7) such that it opposes the front attaching posts (10); opening portions (27), which allow a pivot shaft (36) of a pull-tab (8) to pass through, are provided in side walls (25) on both sides of the cover (7); a proximal portion (29) of the locking pawl (30) is arranged on a rear side of at least one of the opening portions (27); and the proximal portion (29) is bent so that a front end of the locking pawl (30) is located on a forward side, thereby attaching the cover (7) and allowing the locking pawl (30) provided on the cover (7) to be inserted easily into an excess gap between linear fastener elements without damaging sewing yarns or the like.