A Transcription of

Harrison M. Frodsham's

"Some Material for a Résumé of Remontoires"


Installment of April, 1878
(Escapements of De Lafons, Brosse, and Verite)

[The Horological Journal. Vol. ??, No. ?? (April, 1878): 104-105.]

[Page 104]

(Continued from page 88.)

FIG. 1 shows DE LAFONS' escapement 1 with the maintainer (spring C actuating impulse lever B) unarmed, and the balance (E) returning after having received its impulse. The balance moving on (from left to right) will unlock the train by means of fork G, and 'scape-wheel A, being released from hook b of anchor A B, will run on and lock (by the tooth behind A) on hook a, the tooth behind B cathes that lever, arms the maintainer (by tensing spring C) and keeps it locked up.

When the balance returns and unlocks the train again, the 'scape-wheel will move a very little, viz., about the width of the hook a; B relesased from the tooth which supported it is at liberty to fall, roller D is not just in front of the opposite end of B, and consequently receives the impulse due to the tensed spring O.

Fig. 1. De Lafons' Remontoire

Fig. 2 shows another arrangement of De Lafons, in which the spiral C, and the impulse lever B, are replaced by the blade-spring impulse lever D, the 'scape-wheel arms it by lifting the pallet at D, and the action is, otherwise, the same as fig. 1.

Fig. 2. De Lafons' Remontoire [Alternate version]

Fig. 3 [and] Fig. 4. Brosse's Remontoire.

[This is a smaller copy of Figs. 3 and 4 for easier reference from the text.]

Fig. 3 [and] Fig. 4. Brosse's Remontoire.

Figs. 3, 4, 5, 6 and 7, explain BROSSE'S mentioned at page 76. [ February 1878] C D the maintainer, locked up on one of the pins of 'scape-wheel A by a hook at the end of h; it is unlocked by pivotted roller B, fixed at the bottom of the pendulum; as it passes the line of centres the train is locked by the pins of 'scape-wheel A, or by hook e of detent H; it is unlocked (fig. 5) by arm g of maintainer falling on its arm d. The branch i of maintainer C D has a banking for the counterpoise W, so as to bring the hook l when it has fallen in contact with the lifting pins. The 'scape-wheel and maintainer are, it will be seen, at right angles to the plane of the pendulum.

Fig. 5 completion of impulse to the left by maintainer D on roller B. Fig. 7 ditto to the right.

Fig. 9. Verite's Remontoire [1839].

[This is a smaller copy of Fig. 8 for easier reference from the text.]

[Page 105 begins]

VERITE'S, fig. 8, Exhibited Paris, 1839.2

The pin-wheel A, is the 'scape-wheel and re-winder; it is locked by one of the hooks B and C of the detent, D, C, B. At the top of the pendulum, on the bar N K, are fixed two standards, O and L. G, O, is cupped to receive the maintainer (the ball G). L has a wide hook on it, to act on arm D of the train detent and effect the unlocking. The 'scape-wheel limps, as the French say, i.e., it moves nearly the whole distance between the pins at one escape (when it arms and locks up the maintainer) and only the width of the hook at the other (when the maintainer is released).

When G is released, the pendulum is just completing its vibration to the left, consequently, when it descends again it receives all the weight of the ball on the standard O of arm N, and so has its lost force restored to it.

Fig. 9. Verite's Remontoire [1839, another arrangement].

[This is a smaller copy of Fig. 9 for easier reference from the text.]

Fig. 9 is another arrangement by M. VERITE. The pendulum here receives an impulse at each oscillation through the impact of the balls J J' (the maintainers) on the tables K' K of the bar L L, fixed at the top of the pendulum. The re-winder, the eccentric A, by its action on the fork B of the rocker D', B, E, D, alternately re-mounts these balls, which are suspended from the rocker by threads. 3

A is fixed on the arbor of the fly C' C, which makes half a revolution each escape, and locks by a pin on detent E of the rocking piece.

The balls I' I effect the unlocking of the train by pulling down on the arms G' G of the gravity detents G' H' G H, and so letting the pins behind C' C escape from the pad on E, owing to the rocking action of D' D under the influence of J or J'. This escpaement is much anterior to that described at page 52 (fig. 11), [ February 1878] which see, as the description there given saves further explanation here.

[Footnotes to the April, 1878 installment. In the original these footnotes were arranged by column and indicated by asterisks and daggers. They have been gathered and numbered here.]

1 De Lafons received a prize of 30 guineas from the SOCIETY OF ARTS for this escapement, 1801. See Transactions, Vol. XIX., p. 331.

2 Revué Chronometrique, Vol. VI., p. 65.

3 Revué Chronometrique, Vol. VI., p. 72.

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