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Jaw couplings for surgical robots

14 April 2022

Ruland manufactures zero-backlash jaw couplings with a balanced design for reduced vibration and constant velocity in applications that require demanding starts and stops such as those in industries like semiconductor, solar, medical, and packaging.

The dampening ability of Ruland’s jaw couplings aid in reducing settling time and shock loads, making them an ideal option for precision positioning systems

Jaw couplings are a three-piece assembly comprising two aluminium hubs and an elastomeric element called the spider. The spider is made from complex polyurethane which reduces impulse loads that might cause shock to the motor and other sensitive equipment. Available in three durometers, the spider allows the user to tailor the jaw coupling’s torsional stiffness, misalignment, and dampening requirements to their application. 

Ruland jaw couplings feature a curved profile that press fits onto the spider ensuring zero-backlash operation. The curved jaw profile evenly distributes the forces to the centre of the spider’s limbs, improving the effectiveness of the elastomer material. Raised contact points on the spider limbs help maintain proper spacing between the two hubs, allowing for electrical isolation and full angular misalignment capabilities. 

The designer can mix and match clamp or set screw hubs with inch or metric, and keyed or keyless bores. Bore sizes range from 3mm to 32mm and 1/8 inch to 1-1/4 inch. Spiders are available in 85 shore A for the best dampening ability, 92 shore A for a balance of dampening and torsional stiffness, and 98 shore A for the greatest torque and torsional stiffness. This combination of hubs and spiders gives designers a high level of customizability.

All Ruland zero-backlash jaw couplings are manufactured from select North American bar stock in Ruland’s factory in Marlborough, Massachusetts under strict controls using proprietary processes. Full product information, 2D and 3D CAD files, installation videos, and more are available on

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