Oldham couplings are a three piece design comprised of two aluminum hubs press fit onto a center disk. Torque transmission is accomplished by mating the slots on the center disk to the drive tenons on the hubs. During operation the center disk slides on the tenons of each hub (which are orientated 90° apart) to transmit torque. While the couplings accommodate a small amount of angular and axial misalignment, they are especially useful in applications with parallel misalignment.
Ruland offers oldham couplings in set screw or clamp styles with bores ranging from 1/8" (3mm) to 1-1/8" (30mm). Inch and metric hubs (set screw, clamp style, keyed, or keyless) are interchangeable and can be combined into a single coupling as long as they have the same outside diameter. Oldham coupling hubs are standard in black anodized aluminum for improved lubricity, increased life, and low inertia. Hubs are also available in stainless steel upon request for increased corrosion resistance.
The replaceable center disk is available in acetal for high torsional stiffness and zero backlash, or nylon for shock absorption and noise reduction. The slots of the disk mate onto the tenons of the hub with a slight press fit to allow the coupling to operate with zero backlash. In the event of disk wear or failure, the disk can be easily replaced and the oldham coupling's original performance restored. Disks with a center hole are available upon request to allow full shaft penetration.
Ideal for many light duty industrial and motion control applications, oldham couplings have the ability to protect more expensive machinery components. For example the oldham coupling acts as a torque limiter during overload. When the disk fails, it breaks cleanly and does not allow any transmission of power. Oldham couplings also have the advantage of electrical isolation due to the non-conductive nature of the center disk. This prevents electrical currents from being passed to delicate instruments which can cause inaccurate data readings or damage.
Learn more about how to choose an oldham coupling for your particular application from a Ruland expert. Read "What to Look for in a Servo Coupling" or "Tips to Simplify Servo Coupling Selection" written by William Hewitson, Vice President of Operations.