Clocktime: Tompion & Banger Sidereal Regulator 1708, 05 The Movement

Thomas Tompion & Edward Banger - Sidereal Tompion Regulator No. 483 fixed sidereal hour ring, rotating GMT ring from extended hour hand.
Join Dr John C Taylor OBE from the Clocktime digital museum as he discusses the movement of the Tompion & Banger Sidereal Regulator, circa 1708.
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You can see the deadbeat escapement working here. It's always thought that Graham perfected this later but it's possible that this was installed after the clock was modified when Banger left the partnership and Thomas Tompion put his own plate to cover over Banger's name. So, it's possible that they worked on this escapement together before Graham was made a partner. So, look at the massive thick backplate here and the six pillars, three on each side. It's a massive construction holding the gears into correct mesh so there's no movement which would dislodge them. So, Tompion has to get the movement to make the outer dial revolve twice in a year and you can see he has to start off with this huge wheel to move the mechanism because the drive is going to come through the second wheel, down the shaft, which will then show the two worm drives on the front of the clock just behind the dial. So, the arbor comes across to drive the work worm just behind the dial to then move the mechanism up. So, the other end of the horizontal shaft has the worm gear on the end with engaged with the pinion here to give the reduction gear. Here you have the shaft coming up to the single start worm gear here, engaged with the teeth of the dial which revolves twice in a year. So, you can see the worm on the outside of the huge wheel in focus and then the inside of the wheel has these four like little cartwheels with a groove and they support the ring of the gear which then is screwed through to the front, so the chapter ring revolves twice in a year.