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Swagelok Roller Cam Flare Wrench

Applications that use tubing and connectors, such as refrigeration and braking systems, frequently require flare-nut wrenches for service. Such wrenches have split box opening that can slip over a tubing line, yet still grip a connecter at more points than an open-end wrench. For efficient operation, it would be desirable to have flare-nut ratchet wrenches, and several types of ratchet mechanisms have been developed for this need.

One such ratchet flare-nut tool is illustrated by the Swagelok "Cam-Loc" wrench in the photograph. The Cam-Loc mechanism employs a series of small rollers to line the wrench opening, with the rollers held in place by small guide pins. The wrench opening has been forged so that each roller has room to move in one direction, but is blocked (by a rib of the forging) in the other direction. A small spring behind the rollers urges them to remain in contact with the connector.

[Swagelok Roller Cam Flare Wrench]
Swagelok "Cam-Loc" 9/16x11/16 Roller Cam Flare Wrench, with Inset for Reverse.

In operation, when the wrench is turned in the selected direction, the rollers lock in position and bear against the flat of the connector, providing a firm grip for turning. But when turned in the opposite direction, the rollers pivot slightly to one side and ride over the vertices of the connector, allowing it to slip freely. This provides the desired ratchet action.

The wrench is marked with the trademarked brand "Swagelok" and "Crawford Fitting Co.", with "Cam-Loc" and the patent #2,550,010 on the reverse. A check of the trademark records show that "Swagelok" was originally filed by the Crawford Fitting Co. and is now owned by the Swagelok Company. The wrench appears to be made of an aluminum alloy, making it lighter than might be expected for its size.

The Cam-Loc patent was filed by A. Kavalar and issued in 1951. The same inventor later filed the patent for the "Loc-Rite" wrench opening, a design with relieved corners in the broaching to avoid rounding the corners of a connector. This later patent was assigned to Kelsey-Hayes Corp. and used by Bonney and Utica.


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