Reverse-Opening Slider Locking Mechanism for Separable Fasteners
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Solution Overview
Problem
Conventional reverse-opening separable bottom end stops face issues with the reverse-opening slider unintentionally separating due to weight or shaking, leading to complicated manipulation and potential misalignment of element rows, as the locking pawl can easily move from the contact surface, causing unintended separation of the slider and interference with the box pin.
Innovation Solution
A slide fastener with a separable bottom end stop featuring a reverse-opening slider with a locking pawl that includes a first notch portion and a protrusion piece, where the locking pawl is guided into the notch through a slant surface, preventing hooking with the box pin and ensuring stable sliding, and a wider locking plane to prevent unintended movement, along with a separable pin design that avoids interference with the protrusion piece.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the locking pawl is designed to engage with the element guide lane for simple structure, then the device complexity is reduced, but the reliability deteriorates because the locking pawl can easily move from the contact surface causing unintended separation
Solution Approach 1:
The locking pawl is divided into multiple functional segments: a front end portion for initial engagement with the element guide lane, a notched portion with locking surfaces for stable locking, and a rear end portion for actuation. This segmentation allows each part to perform its specific function optimally, improving reliability while maintaining structural simplicity.
Solution Approach 2:
The locking pawl is designed to preliminarily engage with the element guide lane during the closing operation before final locking occurs. The front end portion makes initial contact to guide the element rows into proper alignment, ensuring that the locking action occurs at the optimal moment and position, thereby preventing unintended separation.
2Ease of operation
If the reverse-opening slider is designed to slide freely for ease of operation, then the ease of operation is improved, but the reliability deteriorates because the slider can unintentionally separate due to weight or shaking
Solution Approach 1:
The locking mechanism transitions from a static engagement to a dynamic locking process. As the reverse-opening slider moves along the element rows, the locking pawl dynamically engages with the element guide lane at the appropriate position, providing stability only when needed while maintaining ease of movement during operation.
Solution Approach 2:
The element guide lane acts as an intermediary between the locking pawl and the element rows. It provides a controlled interface that guides the locking pawl into proper engagement while preventing unintended separation, mediating between the need for free sliding and the need for stable positioning.
3Manufacturing precision
If the box pin and separable pin are inserted into standard positions for conventional design, then the manufacturing precision is maintained, but the reliability deteriorates because the locking pawl may hook with the box pin causing interference
Solution Approach 1:
The locking pawl is designed with asymmetric geometry where the front end portion has a different shape and engagement characteristics compared to the notched portion. This asymmetry allows the front end to smoothly pass by the box pin during insertion without hooking, while the notched portion provides secure locking engagement at the correct position, resolving the conflict between standard insertion and smooth operation.
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A separable bottom end stop (1) in which a box pin (20, 20') has a box pin body (21, 21'), a first notch portion 23, 23') for receiving the head end of a locking pawl (36) of a reverse-opening slider (30), and a protrusion piece (24, 24') projecting toward a separable pin (10) in the direction of the tape width from a separable pin facing surface (26) opposed to the separable pin (10). A side wall surface (23b) of the first notch portion (23, 23') and that sectional surface (24a) of the protrusion piece (24, 24') which is provided to the front end side of the box pin are formed in one plane to constitute a locking plane (27) with which the front end of the locking pawl (36) makes contact to lock the reverse-opening slider (30). The box pin body (21, 21') and the protrusion piece (24, 24') have a slant surface (28, 28') declined from the position of the locking plane (27) toward an element row (5). The construction enhances easiness of operation of the reverse-opening slider (30) and reliably prevents the reverse-opening slider (30) from freely sliding from the box pin-side end of the element row without being slid by human force.