MICROSCOPE-ANTIQUES.COM © 2013-21.
GRIFFITH SLIDE-RINGING TURNTABLE
c. 1885
Author: Barry Sobel
Editors: Joseph Zeligs, Jurriaan de Groot
The central ring on the table with 2 pins, 180o from each other is moveable. Originally it was sprung so that the spring would pull it clockwise when it was turned counterclockwise to allow a slide to be attached , but the spring is now missing. Nevertheless, the mechanism still works well manually to center a slide. The series of images below illustrates how this works:
1. The slide is placed between the two pins which rotate on the central disk:
2. The slide is turned counterclockwise, but is pulled back so it can pass the first registration pin (arrow):
3. Counterclockwise rotation continues until the top edge of the slide passes the first fixed registration pin:
4. The slide is now pushed forward towards the second fixed registration pin (arrow):
5. The slide is now registered against the second fixed pin, but not the first:
6. The central disk is now turned, or driven by its spring, if present, clockwise until the slide is registered by all four pins, centering the slide:
7. The hand rest is replaced, ready to ring the slide:
This shows the use of the moveable pin on the small disk which offsets the slide from center:
This shows how a long slide, or a place other than the right to left center of the slide, could be centered with the far left pin unscrewed, falling below the turntable surface. Note the slide is still centered top to bottom
