I repaired this beautiful Ansonia “La Riviere” porcelain cased mantel clock with visible escapement. The clock is 12 1/2 inches tall and 14 inches wide. The minute hand is 1 7/8 inches from center to tip. The 8-day movement strikes the hour and half hour on a cathedral (heavy wire) coil gong. The back of the case says “Royal Bonn, Germany, LaRiviere”.
Repair job 8808. I straightened the tips of the escape wheel teeth, polished the pivots and installed 15 bushings, and installed new return springs on the hammer and count lever.
These Ansonia movements with visible escapement are very efficient and have mainsprings weaker than usual for American antique clocks. The time mainspring is 5/8 inch wide and 0.0145 inch thick (on another one of these I repaired recently, the time mainspring is only 0.0126 inch thick). The strike mainspring is 3/4 inch wide and 0.014 inch thick.
The visible escapement is a deadbeat type known as the pin-pallet or Brocot escapement. In a deadbeat escapement, the escape wheel does not recoil (turn backward slightly) as the pallets engage deeper. The geometry is designed so the minimum pendulum swing (escape arc) is very small, and the actuall running arc can be twice the escape arc (or more). This results in very efficient operation, and is why the time mainspring can be only 5/8″ wide instead of 3/4″.
The pallets are hardened, half-round steel pins mounted in a brass frame (some have half-round jewel pins instead of steel).
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Eek. I did a wood-case version of this movement some years ago. Lesson learned: if this clock works, even inefficiently, leave that external escapement strictly alone.