RACK STRIKING. See HOUR RACK.
RATCHET WHEEL. Saw-toothed wheel. The fronts of the teeth of a ratchet wheel are radial and the backs
straight lines. Used in conjunction with a click (pawl) and spring and fixed by a square hole to the barrel arbor.
The click prevents the wheel turning in the unwinding direction. Ratchet wheel set-up was the first form of
regulation of the fusee watch.
RATE. The timekeeping performance of a watch. Thus 'daily rate' is the term used to denote the difference
between two states of a timekeeper separated by an interval of 24 hours.
RECOIL. Backward movement of the escape wheel during the unlocking process. It occurs when the exit pallet
presses a tooth of the escape wheel backward. In a watch escapement that has draw (q.v.) the e cape wheel recoils
at the instant of unlocking.
RECOIL ESCAPEMENT. An escapement in which recoil takes place, as opposed to a dead-beat or frictional
rest escapement.
REGULATION. In pre-balance spring watches regulation depended primarily upon altering the set-up of the
mainspring. In addition, on some early German watches the supplementary arc could be varied by altering the
position of two upright hog's bristles against which the arms of the balance, or the foliot, banked. As a rare
alternative to this, a long bristle, which could be adjusted as to length, lay across the balance, two upright pins on
which flexed the bristle on each swing of the balance. The earliest form of adjustable set-up is the ratchet and
click, found on fusee watches up to about 1640, when it gave place to the tangent screw and wheel, although the
two forms overlap in period. After the introduction of the balance spring, the set-up was transferred from the top
plate (where it was readily accessible for regulation) to between the plates,regulation now being possible by
altering the effective length of the balance spring, Tompion's form of regulator was universally adopted. It consists
of a segmental rack, which follows the outer coil of the spring, and is geared to a small wheel carrying a key
square and an index dial. Using a key, the position of the curb pins where they embrace the balance spring can be
altered, either shortening or increasing the effective length, thus causing the watch to gain or lose on its previous
rate. The index dial known as the 'figure plate' or 'rosette' gives a guide to the alteration made although the
numbers engraved on it are arbitrary. The only other form of regulation dating from this period was that of
Nathaniel Barrow. This consists of a worm with squared end to take a key. This worm carries a slide on which are
mounted two curb pins embracing the straightened outer end of the balance spring. The slide has a pointer which
moves across an index engraved on the movement plate, thus indicating the amount the slide has moved when
regulating. Very few watches with this form of regulation have survived. In 1755 Joseph Bosley patented 'A
new-invented slide, which slide has no wheel attached to it'; that is, he dispensed with the Tompion segmental rack.
Bosley's consisted of a small lever, the shorter end of which carries the curb pins which embrace the balance
spring, the longer end (by which it is moved) travels across a scale which served to indicate the alteration to 'fast'
or 'slow' in the position of the curb pins. A 'free-sprung' watch can only be regulated by altering the timing screws
on the balance.
REGULATOR. See INDEX.
REMONTOIRE. A spring (or other device) which is wound by the train and discharged at regular intervals.
REMONTOIRE ESCAPEMENT. An escapement employing a remontoire which is interposed between the
escape wheel and the balance to ensure constant force to the balance. The distinction between a remontoire and a
remontoire escapement lies in the point at which the remontoire is introduced. In the former it is interposed
between the mainspring and the escape wheel, and in the latter between the escape wheel and the balance. In both
cases the purpose is to secure a more constant torque than is delivered by the driving train. Such an escapement is
also known as a 'constant force escapement'.
REPEATER. A repeating watch in which mechanism can be set in motion to denote the approximate time by
hammers striking bells, gongs or a block within the watch case, This last is known as a 'dumb repeater'.
Repeating work was invented by Daniel Quare between 1680 and 1686. Matthew Stogden introduced
improvements about 1725.
REPOUSSE. Decoration achieved by hammering metal from the back into a shape or pattern resulting in relief
decoration. A similar effect is given by casting.
REPUBLICAN CALENDAR. Introduced in France in 1792, and in use until January, 1806.
RESILIENT ESCAPEMENT. A form of lever escapement in which the impulse pin, when pressing on the
outside of the lever, causes the lever to yield and allow the pin to pass.
ROBIN ESCAPEMENT. Introduced by the 18th-century French watchmaker of that name. It is a single beat
escapement, impulse being given by the escape wheel, locking taking place on the lever. A rare escapement of
which Breguet made a number.
ROLLER. In the lever escapement, the disc fitted on the balance staff and carrying the impulse pin, the latter
receiving impulse via the pallets. This is the single or table roller. In later lever escapements, with double rollers, a
smaller, safety roller was introduced which has a crescent or passing-hollow cut in it for the guard pin. Also see
TABLE ROLLER and CRANK LEVER ESCAPEMENT. In the duplex escapement (q.v.) the roller is a hollow ruby
cylinder against which the teeth of the escape wheel are locked.
ROSKOPF. G. T. Roskopf manufactured the first cheap and successful watches in 1867. The Roskopf
escapement is basically a lever, but the impulse pin and pallets are steel pins. The modern form is called a 'pin
lever'. The pin-pallet is not exclusively Roskopf.
RUBY CYLINDER ESCAPAPEMENT. A cylinder escapement in which the cylinder shell is made out of
ruby. It was probably introduced by John Arnold in 1764, though not used to any extent for some years. The
second John Ellicott used it in his later cylinder watches, but it was very popular with Breguet.
RUN-TO-BANKING. In the lever escapement, the movement of the lever towards the banking pins after a tooth
has given impulse to the pallet. This is a safety factor to ensure the passage of the escape wheel teeth. See DRAW.
