Locking Device With Angled Protrusions For Bag Fastening
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Solution Overview
Problem
Conventional screw-type and rivet-type locking devices for bags suffer from reduced combination force due to wear and require separate pressing processes, leading to low workability and potential separation of components during use.
Innovation Solution
A locking device featuring a locking washer that combines the upper and lower body parts with a locking washer, which includes protrusions angled between 25 to 35 degrees to provide a strong and uniform force for fixation, allowing easy opening and closing of the bag.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a screw-type locking device is used to combine upper and lower plates, then the combination force is initially strong, but the combination force decreases over time due to wear from relative rotation
Solution Approach 1:
The patent extracts the rotational movement function from the locking mechanism by using a snap-fit body that rotates independently within the upper plate, while the locking washer remains stationary. This separation prevents wear between the locking washer and lower plate, maintaining constant combination force throughout service life.
Solution Approach 2:
Instead of having the locking washer rotate with the body (conventional approach), the patent inverts the design so that the body rotates within the upper plate while the locking washer stays fixed. This reversal eliminates wear on the locking interface, resolving the contradiction between initial strength and durability.
2Strength
If a rivet-type locking device is used to combine upper and lower plates, then the combination is initially strong, but the fabric interposed between plates wears out due to relative rotation
Solution Approach 1:
The patent extracts the rotational function from the locking washer assembly, allowing only the snap-fit body to rotate. This prevents relative rotation between the locking washer and lower plate, eliminating the harmful friction that causes fabric wear while maintaining strong initial combination force.
3Strength
If a conventional rivet-type locking device is used, then the upper and lower plates are strongly combined, but a separate press or pressing process is required
Solution Approach 1:
The locking washer features angled protrusions (25-35 degrees) that automatically engage with grooves on the lower plate during assembly. This self-aligning, self-locking mechanism eliminates the need for separate pressing or riveting processes, improving workability while maintaining strong combination force.
Solution Approach 2:
The patent changes the geometric parameters of the locking washer by incorporating angled protrusions with specific angles (25-35 degrees). This parameter modification enables automatic engagement during assembly, eliminating complex pressing processes and significantly improving ease of manufacture.
4Strength
If protrusions with larger angles are used in the locking washer, then the combination force increases, but the protrusions become harder to insert into the lower body part
Solution Approach 1:
The patent optimizes the protrusion angle parameter to a specific range (25-35 degrees). This parameter selection achieves the optimal balance: angles within this range generate sufficient combination force while maintaining reasonable insertion ease, avoiding the extremes of too shallow (weak force) or too steep (difficult insertion).
Data Source
AI summary
There is provided a locking device including: a locking unit capable of performing locking and unlocking operations by rotation; an upper body part in which a first connection hole is formed; a body part which is inserted into the first connection hole of the upper body part and combined with one end of the locking unit; a lower body part in which a third connection hole into which the body part is inserted from below is formed; and a locking washer which is positioned between the upper body part and the lower body part and configured to fix and combine the upper body part and the lower body part.