US 4,238,164 AGranted

Positive locking device for telescoping tubing

AssigneeH & G Industries, Inc.

InventorRichard Mazzolla

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Abstract

An externally threaded mandrel extends from one end of the inner tube of a pair of telescoping tubes and is staked thereto. A trifurcated collet threads on the mandrel whereby a conical exterior surface on the mandrel cooperates with a conical interior surface of the collet. Longitudinal ridges on the inner surface of the outer tube interlock with longitudinal grooves on the collet preventing relative motion between the outer tube and the collet while permitting longitudinal translation of the outer tube relative to the inner tube. Rotation of the inner tube in one direction advances the mandrel into the collet, with the interacting conical surfaces driving the furcate segments of the collet outward against the inner wall of the outer tube until a tight fit is produced. Friction between the collet and tube wall locks the tubes together. Reverse rotation of the inner tube withdraws the mandrel and releases the outer tube from the grip of the collet segments. The collet is made of a resilient plastic material.

Claims8

Dependent claims

A positive locking device for releasably joining a first tube to a second tube, comprising:

a mandrel including means for fixedly attaching said mandrel to said first tube, said mandrel having a threaded portion and a conical portion;
a collet, said collet having a central opening therethrough, said central opening including a threaded portion and a conical portion, said mandrel being positioned inside said central opening with said threaded portion of said mandrel engaging said threaded portion of said collet, and said conical portion of said mandrel substantially opposing said conical portion of said collet;
movable means cooperating with said conical portion of said collet and adapted to fit inside said second tube, the threading of said mandrel into said collet causing said conical portion of said mandrel to contact said conical portion of said collet and drive said movable means outwardly;
means for preventing rotational motion between said collet and said movable means and said second tube when said mandrel is rotated for threading into said collet and for unthreading including longitudinal grooves on said collet engaging longitudinal ridges on said second tube,
whereby when said mandrel is connected to said first tube and said movable means is within said second tube, said tubes are locked together by pressurized contact of said movable means with said second tube when said mandrel is threaded into said collet.

2 more elements

Dependencies are inferred from the claim text.