Precision Horology
Precision Horology


Each pendulum rod is mounted in a gimbal type holder which has arms attached to it that are perpendicular to the pendulum rods and knife edges. These perpendicular rods – a pair on either side of each pendulum rod - are made of quartz and at the end of each one is fastened a small cobalt magnet. These magnets sit above the impulse coils. The coils themselves are wound on polycarbonate forms and have no cores. They are wound of #36 magnet wire.

Below each pendulum there is a small laser assembly that is mounted in an adjustable holder assembly. Although the lasers are mounted horizontally, a prism and lens assembly changes the direction of the beam so that it emerges in a tightly focused vertical beam. Each laser assembly is mounted so that the quartz pendulum rod passes over it. The bottom of the pendulum rod is polished and fitted with a tiny aperture so that when the pendulum rod passes over the laser at its exact center, the laser beam shoots up the pendulum rod. The top of the pendulum rod is also polished and fitted with a simple plano-convex lens to concentrate the beam. Above each pendulum rod, a fiber optic light pipe is fixed which captures the light beam that travels up the quartz rod. The light pipe is connected to a diode that converts the light to an electrical signal which operates the logic relays which in turn give impulse to each pendulum in the proper direction. The pendulums are given impulse in each direction of travel. The simple relay logic that determines which direction to impulse each pendulum is controlled by four photocell assemblies mounted on the movement. The impulse arms which are fitted to the pendulum rod holder assemblies have small vertical blades attached - above the magnets - that act as interrupters

to the photocells. They control the logic that determines which of the pendulums is given impulse and in what direction.

A core and an unfinished wound coil. I machined the forms with an integral mounting base.

You can clearly see the quartz arms attached to the pendulum rod gimbals. Magnets affixed to the  impulse arms sit above the coils. The photocell interruptor blades sit above the magnets.

The laser assembly. The adjustment micrometers on the right side are biased by the springs in the left. The prisms change the horizontal beam to vertical.

One of the impulse coils being wound.

The CNC coil  winding machine which can automatically wind any size coil.

The two pendulums in the test setup in a check of the laser lenses.