Replacing point contacts with line contacts boosts load capacity of kinematic mounts.
Kinematic Mounts By The Numbers
Sphere-to-groove point contacts are what limit load capacity in conventional sphere-based kinematic mounts. Those with a V-groove full angle of 120° handle more load than with 90°, but at the expense of weaker centering forces. Spherolinders replace the point contacts with line contacts. Maximum allowed forces at the contact interfaces are:
The top, spherical portion of a Spherolinder touches a cone about a circumference. The bottom, cylindrical portion has two line contacts whose total length equals twice the cylinder length.
The length of a cone-sphere contact line is:
The optimal length to match load capacity of both the top and bottom Spherolinder surfaces (assuming a 90° cone) is:
The above calculations are for a single mounting site. A complete mount contains three mounting sites so load is adjusted accordingly.