Valve and tube manufacturers continue to battle the problem of fitting pipes and tubing together quickly and reliably. The spring drive fitting addresses this challenge, bridging the gap between solutions for small-diameter tube fittings commonly seen in high-pressure, low-flow-area pneumatic systems and solutions for large flanges used in low-pressure, high-flow-area hydraulic systems.

The spring drive fitting integrates with existing technologies for joining small-diameter tube fittings and combines the benefits of a wave spring and threaded connection, therefore eliminating the problem of friction-limiting preload during installation, which plagues connections between 2” and 10” in diameter. The fitting consists of three elements: a fitting body, driving ferrule, and the spring drive.

To install the fitting, the spring drive is first elongated by elastically stretching the integrated preloading beams. The spring drive can be stored in the preloaded state via special tooling using exterior pins. The spring drive is then assembled snug to the fitting body and driving ferrule. Removing the exterior tooling from the spring drive transfers the preload stored in the elongated preloading beams into the joint and contracts the spring drive. This drives the ferrule into the tube and secures the fitting into place.

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Tech Briefs Magazine

This article first appeared in the March, 2020 issue of Tech Briefs Magazine.

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