Exceptional Collectors Timepieces, Ho...

Geneva, May 15, 2005

LOT 98

Charles Bacon, Gerrard Street, Islington, London. Made circa 1865. Extremely fine and rare eight-day mahogany and brass precision wall regulator with Anti-Friction Rollers and Deadbeat Escapement.

CHF 35,000 - 45,000

EUR 23,000 - 29,000 / USD 30,000 - 40,000

Sold: CHF 46,000

C. Rectangular, with oak carcass veneered with flecked mahogany, the edges inset with mahogany round-edgebeading, glazed sides and door with cavetto brass frames. D. Silvered, circular, outer minute track with Arabic fiveminute markers, hour dial at 6 with radial Roman numerals, seconds dial at 12, inclined silvered bezel. Blued steelhands. M. Massive, rectangular polished brass plates with shaped shoulders, four massive turned pillars securedby blued steel screws, wheels with six crossings, each pivot with polished steel endplate, the great-wheel withbrass endplates, Harrison's maintaining power, anti-friction deadbeat escapement with jeweled pallets andmounted between the dial and front plate, the escape-wheel pinion passing through the front plate and supportedby two crossed-out sub-frames, one extending between the two top pillars within the movement , the otherbetween the upper dial feet, the pallet arbor mounted on a sleeve around the pinion terminating in a vertical roller-armfacing a similar arm mounted on the pinion itself, flat steel springs either side allowing movement betweenthe two, the end of the pivot resting upon two six-spoke anti-friction rollers supported by a crossed out sub-frame,beat adjustment above the crutch and steel stop-pins either side. The movement supported by a massive brassbracket secured to the back of the case and secured to the bracket by two thumb-screws, mercury pendulum withbrass-capped glass jar and steel rod suspended from the bracket, rating nut, blued steel pointer above silveredscale calibrated 0 - 4, offset brass-clad lead weight suspended from two pulleys, one with ball bearings.Dial signed.Dim. 141.5 x 33.5 x 21 cm.


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Grading System
Grade:
Case: 3

Good
Movement: 3*

Good

Overhaul recommended, at buyer's expense
Dial: 3 - 01

Notes

The fine quality and elegant case shows that this clock was intended not only as a fine precision instrument but also for display. Charles Bacon is recorded as being an escapement maker working at 37, Gerrard Street, Islington until 1917. The refine-ments to the movement, all intended to reduce friction, suggest that this regulator was either a special order or perhaps Bacon's own regulator. Because the escapement is located between the dial and the front plate, the under-dial work has been eliminated. This has been achieved by the addition of a further wheel fitted to the rear of the great wheel which meshes with an hour wheel of similar count, thus all the hands are set independently. Steel stop-pins are positioned either side of the crutch to prevent damage to the jeweled escape pallets and the offset pulley to drop the weight at the side of the case reduces the chance of any interference with the pendulum. A very interesting and rare feature of this clock are the sprung roller arms fitted to the pallet arbor pinion. This allows the fixed pallet arms of the deadbeat escapement the freedom to move should any excess force transmit to the escapement, thus creating a secondary anti-shock device. The friction created by the crutch fork on the pendulum is done away with by this arrangement and it also allows no interference to the arc of the pendulum. Mercury Pendulums Have a steel rod and a mercury filled cylindrical glass or iron bob. The length of the mercury column increases with temperature, counteracting the expansion of the steel rod and keeping the effective length of the pendulum constant. It was invented by George Graham in 1726. Anti-Friction Rollers Sometimes used in an attempt to reduce friction or prevent undue loading on a pivot by supporting the arbor with rollers. Harrison was one of the first to use them on his sea clocks and Vulliaumy, Reid and Dennison all employed them on regulators. They are normally used to support the lower wheels in the train where the most force is exerted, but occasionally, as in the present clock, they are used to support the crutch pivot. Deadbeat Escapement Invented by George Graham in 1715, it is called the ?deadbeat? because when a tooth of the escape wheel has dropped onto the pallet, the escape wheel does not recoil but remains motionless.