Oldham couplings suit medical device applications

Ruland Paradrive oldham couplings are a three-piece design comprised of two hubs and a floating centre disk.

Ruland Paradrive oldham couplings are a three-piece design comprised of two hubs and a floating centre disk.

The centre disk, which is available in acetal for high torsional stiffness or nylon for shock absorption and vibration dampening, is the torque transmitting element.

Torque transmission is accomplished by mating slots in the centre disk, located on opposite sides of the disk and oriented 90 degrees apart, with the drive tenons on the hubs.

The slots fit with a slight press fit.

The press fit allows the coupling (with acetal disk) to operate with zero backlash.

In operation, the centre disk slides on the tenon of the hub to accommodate misalignment with light bearing loads.

The oldham design has many advantages.

Like jaw couplings, the three-piece design eases blind assembly.

However, unlike the jaw couplings, oldham couplings are particularly well suited for handling misalignment, particularly large amounts of parallel offset, without stressing bearings and seals.

Ruland Paradrive oldham coupling hubs are machined to a fine finish, resulting in a longer zero backlash life.

The result is substantial savings in terms of maintenance and machine downtime.

The hubs are also balanced to allow for higher speeds.

While over time the sliding of the disk will create wear and the coupling will cease to be zero backlash, the disk can be easily replaced and the coupling's original performance restored.

The disks are also electrically isolating and can act as a mechanical fuse.

When the disk fails it breaks cleanly and does not allow any transmission of power, preventing other damage from occurring to more expensive machinery components.

Paradrive oldham couplings are offered in seven sizes of set screw or Nomar clamp style hubs with bore from 3 to 25mm.

The hubs are anodised for improved lubricity and increased life.

The couplings feature a balanced design for reduced vibration in higher speed applications.

Common applications for Paradrive oldham couplings include encoders, positioning systems using servo and stepper motors, and other light duty drives.

They are also useful in applications where easy component removal is desired.

For example, they can be used to attach rollers on presses so that easy removal for cleaning is facilitated.

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