Quasi-Kinematic Coupling

Technology #8692

Questions about this technology? Ask a Technology Manager

Download Printable PDF

Image Gallery
Quasi-kinematic (A) and kinematic (B) couplings.Planar constraints in kinematic (left) and quasi-kinematic (right) couplingsGeometry of (A) compliant quasi-kinematic ball and (B) cross-section of a QKC joint.
Professor Alexander Slocum
Department of Mechanical Engineering, MIT
External Link (pergatory.mit.edu)
Professor Martin Culpepper
Department of Mechanical Engineering, MIT
External Link (meche.mit.edu)
Managed By
Christopher Noble
MIT Technology Licensing Officer - Clean and Renewable Energy
Patent Protection

Quasi-Kinematic Coupling and Methods for use in Assembling and Locating Mechanical Components and the Like

US Patent 6,193,430
Design of Quasi-Kinematic Couplings
Science Direct, Volume 28, Issue 3, July 2004, Pages 338–357


Quasi-kinematic couplings eliminate gaps between mated components that occur in kinematic couplings. These couplings can be used in precision alignment of product components, tooling, and fixtures.

Problem Addressed

Certain types of prior kinematic couplings have been used to provide affordable submicron repeatability; however, their operation generally leaves gaps between the mated components, and they are therefore not well-suited for applications that require contact or sealing, such as casting. This invention overcomes such limitations by using conical shaped grooves with relieved sides which can direct a desired portion of their error resistance along a direction without seriously compromising the resistance to error in an orthogonal direction.


A traditional kinematic coupling has six distinct points of contact, such as provided by three hemispheres making contact with three Vee-grooves. This technology is similar, but the vee-grooves are curved to form cones with relieved sides. The hemispheres make contact with the curved surfaces, and the stiffness in a direction orthogonal or normal to the cone surface is very high – much higher than any restraint in a direction tangent to the contact normal. Hence, mathematically, in terms of dominant stiffness of the system, the system will behave as if kinematically coupled.


  • Leaves no gaps between mated components and ensures cooling