Trivet, 14 " Indexing

Part No.: INDTRI14

The 14" Indexing Trivit

This lightweight device, a trivet, is designed to provide precise, repeatable, indexing of the "Geostep" (see "Geostep" technical data sheet) or other C.M.M. calibration devices. Most of the hardware used in this setup are part of our off the shelf line of components. By using these standard components, this rather sophisticated device can be produced for a very modest cost.

Our standard "14-inch Trivet" is modified to become the upper rotating half of this Kinematically positioned indexing system.

The indexing lever is simply rotated 90°, to raise the "Trivet". The "Trivet" is then indexed to the next position. When the lever is returned to its original position, it lowers the "Trivet" onto the Kinematic spheres of its new orientation and the next measurements can be made. This system provides six precise, repeatable positions. They start at 0° then to 60° then 120° then 180° then 240° then 300° and then back to zero, or 360°.

The calibration device or devices used for the C.M.M. evaluation are held in position at the desired height by using the ideal height of "Anchor" (see the "Anchor" technical data sheet in the C.M.M. catalog, for the standard heights available).

To hold the "Geostep" in perfect position, the "Geoclamp" is attached to the top of the "Anchor" and the "Geostep" is installed between the two parallel clamping plates. In order to keep the weight of the "Geoclamp" to a minimum, it is constructed almost entirely of aluminum.

The circular base of this system forms a truly Kinematic indexing device. It is constructed of a lightweight, aircraft quality, aluminum casting.

Twenty four ( 24 ) very precisely ground and lapped spherical components are rigidly fixed to give precise fifteen degree ( 15° ) increments in the top surface of the base casting. The upper half of the Kinematic indexing system consists of three pair of our standard split Kinematic vee blocks (see Split Vee Blocks technical data sheet under Kinematic products) that are rigidly mounted in three precision-machined trenches in the Trivet.

When working with automatic self-propelled C.M.M.'s, totally automatic measuring of the calibration artifacts can be achieved using the indexing Trivet.

With the twenty four spheres on the base ring, every twelfth sphere is 180 degrees apart. By measuring and aligning any two of the Kinematic spheres that are at 180 degrees to each other, with the "X" axis of the C.M.M., the position of the artifact will be aligned well enough for automatic re-measurement.

The material chosen for the vees and the spheres of the indexing Trivet is a very high chrome, high carbon, Martensitic stainless steel. This ultra fine-grained material is through hardened to 58 HRC (Hardness on the Rockwell "C" scale) minimum.

This indexing Trivet can also be supplied in custom configurations with orthogonal or other angular configurations.