Universal Joints (U-Joints)

ISC Companies and affiliate Adams-ISC are distributors of mechanical power transmission parts including Universal Joints (U-Joints). For more information about the brands we offer and/or pricing, please contact us by phone 763-559-0033, by email custserv@isccompanies.com, or by filling out our online contact form.

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Mechanically flexible U-Joints accommodate end movement by using a telescoping shaft (square shafting or splines). U-Joints function by a sliding motion between two flanges that are fork-shaped (a yoke) and having a hole (eye) radially through the eye that is connected by a cross. They allow larger angles than flexible couplings and are used in applications where high misalignment needs to be accommodated (1 to 30 degrees).

U-joints are available with two hub styles; solid and bored. Solid hubs do not have a machined hole. Bored hubs have a hole and are named for the hole shape; round, hex, or square style. Two bored styles that deviate from these common shapes are splined, which have longitudinal grooves inside the bore; and keyed, which have keyways to prevent rotation of the U-joint on the shaft.

There are many varieties of U-Joints, some of which are very complex. The simplest category called Cardan U-Joints, are either block-and-pin or bearing-and-cross types.

Common Cardan U-Joint Types

Block-and-Pin U-Joints

Available in both single and double configurations. A single U-Joint has two shafts with u-shaped and drilled ends, a center block, and two pins that secure the block. Vibrations, caused by velocity changes, limits this type to very low speeds. A double U-Joint has a center piece connected on each end with separate joints.

A single U-Joint compensates for angular misalignment, and a double can handle angular and parallel misalignment. If changes in misalignment or shaft end movement occur, a telescoping splined shaft provides the necessary adjustment in shaft length.

Bearing-and-Cross U-Joints

Two u-shaped hubs are joined by a cross-shaped piece. Needle bearings at each end of the cross-shaped piece fit into the hub arms. They are torsionally rigid and capable of up 15 degrees of angular misalignment.