The Queen Contact Breaker for Large Coils.
This is a device where the actual break is made in alcohol between large studs of platinum nearly one-quarter inch in diameter. The bottom contact can be raised or lowered by means of an adjusting screw. The top contact is secured into the bottom end of a rod passing down a guide tube into the alcohol to meet the lower contact. By means of an electric motor and a cam motion, the top contact and plunger are made to work up and down in the alcohol, thus making and breaking the current flow. One of the commendable features of this contact breaker is that the platinum studs are caused to revolve while in operation, thus presenting new faces to each other after each blow. The apparatus is not adapted for rapid action, but for the handling of heavy currents.
Adjustable Contact Breaker for Medical Coils.
An adjustable contact breaker for medical coils is shown in Fig. 26. M M are the magnet coils, A is the armature, carrying a platinum contact, which vibrates against the adjusting screw P. The armature is pivoted at J, but is held at a distance from the magnets by the springs S S. The other end of the armature carries a ball B, which can be slid up and down on the rod and set at any point by a set-screw. When the ball is at the end of the armature rod most remote from the magnets, the vibrations are slowest; when moved towards the magnets, the vibrations become more rapid. Adjustment of the two springs S S at R R enables the contact breaker to operate on varying current strength, and also tends to lessen the jerkiness of gravity contact breakers. A flat spring, however, can be substituted for the spiral springs, in which case the pivot would be dispensed with and the spring riveted, as in the hammer form of vibrator. The illustration shows this arranged for a wall board, but it can readily be adapted for table work.
Fig. 26.