A Transcription of

Harrison M. Frodsham's

"Some Material for a Résumé of Remontoires"


Installment of August, 1878
(Escapements of Herrmann, Gowlands, Benoit, and Gaudron)

[The Horological Journal. Vol. ??, No. ?? (August, 1878): 163-165.]

[Page 163]



(Continued from page 131.)

In the arrangement by HERRMANN1 shown in fig. 1, the impulse lever L (axis at J), actuated by the spiral M (the maintainer), is seen locked up by arm l on the stone S of detent D, having been armed by cog 1 of the duplex-scape-wheel W, and that wheel is stopped by locking tooth 1 resting on roller R of the impulse lever.

When the balance, by discharging roller A, has released l from S, the pin p will fall on the jewel of roller B, and give impulse; at the end of the excursion of L, locking toth 1 will be able to escape from roller R, cog 2 will therefore arm the maintainer by its action on pallet P, and locking tooth 2 will come to rest on R, and thus all is in readiness for a fresh impulse.

Fig. 1 - HERRMANN'S REMONTOIRE. [reduced size image]


GOWLANDS'2 invention consists of an escapement which communicates motion or impulses to the balance through the medium of the balance-spring.

[Note: Figs. 2 and 3 appeared originally on page 162, and are reproduced here at reduced size for ease of reference from the text.]

Fig. 2 - PLAN OF GOWLANDS' REMONTOIRE. [reduced size image]

In fig. 2 the upper part of the cock and nearly the whole of the balance-spring (marked S, S, in fig. 3), are removed to show the various parts, leaving a portion of the balance-spring S, S, in fig. 2, and also a portion of the balance axis L in fig. 1 [sic] to which is attached the unlocking pallet K.


Fig. 3 shows a vertical section of the same escapement (as if takent rhough the dotted line in fig. 2). W, represents the plate, with the part marked V, cut away, to which the whole escapement is attached by means of the union screw U. The cock is screwed to the potence C, C, by means of the screws, one of which is represented in this fig. and marked B. The counterpotence E, is attached to the potence by the screw D and proper steady pins. F, F, is the escape-pinion, working in jewelled settings fixed in the potence C, and counterpotence E, E, and driven by the fourth wheel as usual. On the upper part of the escape-pinion arbor is firmly fitted the revolving escapement bar G, G, G. This bar carries the locking spring I, I, with its banking screw H, the unlocking spring J, with its banking screw Y, and the balance-spring stud P. The balance M, M, M, M, with its mean-time weights N, N, N, N, works with one end of its axis L in a jewelled setting in the cock A, A, and the other end of the axis L, having a jewelled setting inserted in it, works upon the top of escape-pinion F, F. The inner end of the balance-spring S, S, which in this drawing is represented of the flat kind (but may be in any of the usual forms), is fixed upon the axis of the balance by its collet R, R, in the usual way; the outer end of the balance-spring S, S, is fixed to the revolving escapement bar G, G, G, by the stud P; upon the lower and of the balance axis L, figs. 2 and 3, is fitted the unlocking pallet K. The part O, O, O, O, figs. 2 and 3, is a locking rim, which is screwed to the potence plate C, C, concentric with the axis of the escape-pinion F, F. This locking rim is equally divided by a number of notches according to the number of beats the chronometer is designed to have. These notches are ach of the same width as the locking pallet f, figs. 2 and 3. The teeth thus formed between these spaces have their exterior surfaces curved in such a manner as to bring the extremity of each tooth marked a a [page 164 begins here] little nearer to the centre of the rim than the extremity marked b.

In fig. 2 the direction of motion of balance with its unlocking pallet K, is indicated by the inner arrow c as moving from right to left, the escapement bar G, G, G, with stud P being firmly locked in one of the notches of the locking rim by means of the locking spring I, I, and the locking pallet f. The unlocking pallet K in its progress then comes into contact with the foot of the unlocking spring J, and raises it into the position shown by the dotted lines, by which means the locking pallet f is forced out of the space or notch cut in the locking rim O, O, and thus the train, being allowed to act upon the revolving escapement bar G, G, G, carries it partly round in the direction indicated by the arrow, d, until it comes against the face of the next tooth in the locking rim, the unlocking pallet K, at the same time disengaging itself from the unlocking spring J, J, the locking pallet is forced into the notch of the locking rim, and is again firmly locked. During this progression of the revolving escapement bar G, G, G, the stud P has been moved forward, drawing with it the outer end of the balance spring S, whilst the balance is still proceeding to the extremity of its motion, as indicated by the direction of the arrow c; when the balance returns to the right it revolves with the momentum due to the force of the impulse received by the balance-spring S, being moved forwards as above shown. When the balance is revolving in this direction pallet K pushes aside without raising the locking piece f. The balance then progresses on until its momentum in this direction is expended, when it returns and repeats the action. The bar G, G, G, when locked is prevented from being moved round in either direction by the locking piece f being, by the pressure of the locking-spring I, I, firmly held in one of the notches of the locking rim between the face a and the face b of two of the teeth. The face b of each tooth of the locking rim is made to project for the purpose of catching the locking piece f when it comes to the notch into which it falls.



After this elaborate and perhaps confusing exposition of one method of communicating impulse to the balance through the spring, a very short description of another method - by Benoit3 - must suffice (Figs. 4 and 5).

[reduced size image]

As in Gowlands, the "stud," instead of being fixed on the cock, is on a disc, h, on the arbor fo the 'scape-wheel A B, and the end of the spring is therefore moved a little onwards every time the train escapes. The train is locked (fig. 5) by the anchor k, o, i, (axis at o), which is kept steady by the spring m.

The method of locking is as follows: When the balance revolves in the direction of the arrow u, v, tooth d'' will knock against catch r', owing to the train being backed a little by the tension of the balance spring, and will so cause catch r to stand clear of intersection with the 'scape-wheel; consequently, when the balance returns, tooth d will pass r, and tooth d' will lock on r', moving the anchor a little and pulling catch r again into intersection with the 'scape-wheel.


Fig. 6 represents a train remontoire à la Hughens [sic], designed by PIERRE GAUDRON for the Regent the Duke of Orleans, in 1717.4 The toothed barrel P, which goes 15 days, only drives the train Q, F, L, whose locking is (by a fly or pinion L) at I on the detent piece G, B, H, I (axis at G). The "centre" wheel E is driven by the maintainer A, which hangs by the cord over its pulley C, and also over pulley D on the arbor of F. The detent piece G, H, rests on the frame of pulley B, and descends with it as C, D, E, move. When it has fallen enough to let the locking fly escape from its detent at I, the rewinder train, impelled by P, will drive the maintainer A until the fly again rests on I. The wheel E continues to go while A is being armed because U is still driving it.

Fig. 6 - GAUDRON'S REMONTOIRE. [reduced size image]


CORRECTIONS. - In fig. 10, page 130 [June 1878], the fusee thread should have sloped the other way. In lines 8, 9, 10, "pallet o" and "pallet l" are to be read in the reverse order.

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

1 Specification 2447 [sic; this seems a low number for 1866], A.D. 1866; see also Vol. XI of the [Horological?] Journal, page 20.

2 Specification 7456, A. D. 1837.

3 Revue Chronométrique. Vol. iv., p. 500, plate 57.

4 Consult F. A. LEPAUTE'S Traité d'Horlogerie. Paris: 1767; and THIOUT, Paris, 1741.

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