Rotating Sleeve Pipe Fitting to Prevent Tube Surface Damage
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Solution Overview
Problem
Conventional fittings with locking functions can damage the outer circumferential surface of tubes due to the restricting piece when connecting them, as the tube is pushed to engage with the lock ring.
Innovation Solution
A fitting design featuring a chuck, sleeve, and guide mechanism that allows the engaging piece's claw portion to be locked to the tube without contact during insertion by rotating the sleeve to a first position, and then locked at a second position to secure the tube, using a rotation locking mechanism and a lock release mechanism to prevent damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the restricting piece bites into the tube to prevent pulling out, then the locking function is improved, but the outer circumferential surface of the tube is damaged
Solution Approach 1:
The sleeve is rotated to the first rotational position before tube insertion, which preliminarily positions the engaging piece so that its claw portion does not contact the tube. This preliminary positioning prevents damage during insertion, and after insertion the sleeve is rotated to the second position to engage the claw with the tube for locking
Solution Approach 2:
The sleeve is designed to be rotatable between different rotational positions, transforming the static locking mechanism into a dynamic one. The engaging piece's claw portion can dynamically adjust its position relative to the tube - non-contacting during insertion and contacting for locking - by rotating the sleeve between first and second positions
2Reliability
If the claw portion contacts the tube during insertion, then the locking function is achieved, but the tube surface is damaged
Solution Approach 1:
Before tube insertion, the sleeve is rotated to the first rotational position as a preliminary action, which positions the engaging piece's claw portion away from the tube surface. This ensures the tube can be inserted without the claw contacting or damaging it, while still maintaining the capability to lock after insertion
3Object-affected harmful factors
If the sleeve is rotatable to guide the engaging piece, then the damage to tube is prevented, but the device complexity increases
Solution Approach 1:
The rotatable sleeve serves multiple functions: it guides the engaging piece during insertion, prevents claw contact with the tube to avoid damage, and enables the locking function by rotating to engage the claw with the tube. This multi-functionality reduces the need for separate components for each function
Data Source
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AI summary
A chuck (12, 12A) that is stored in a sleeve (44, 44A) has an engagement piece (18, 18A) formed with a claw part (18c, 74) capable of being locked to an outer surface of a tube (62). The sleeve (44, 44A) is rotatable between a first rotation position and a second rotation position relative to a body (24, 24A). A pipe fitting (10, 10A) comprises: a cam part (46, 46A) that guides the engagement piece (18, 18A) along with the rotation of the sleeve (44, 44A), in such a way that the distance from the engagement piece (18, 18A) to the axial center of the chuck (12, 12A) changes; and an unlock mechanism for removing restriction on the rotation of the sleeve (44, 44A) in accordance with the insertion of the tube (62) to a predetermined position.