[The Horological Journal. Vol. ??, No. ?? (January, 1878): 66-67.]
(Continued from page 53.)
The maintainers are the springs h h, actuating the levers f k g l; they are armed by the teeth of the escape-wheel lifting their respective pallets: k impels the balance to the right, and l to the left by their action on the finger d of the balance staff.
The maintainers are locked up by their pallets not being allowed to escape the tooth of the wheel which lifts them until the train is unlocked by the balance.
The train is locked on the detents of the anchor n, and unlocked by discharging roller c acting on lever o through the spring r.
Spring r has so much play across lever o before banking at the end (see q, fig. 4) as insures that the unlocking takes place just after finger d gets inside the maintainer from which it is to receive its impulse.
Fig. 2. - Tooth t has armed maintainer h by lifting its pallet f and keeps it armed, the train being locked (by tooth u on one of the detents of anchor n) before t has passed the summit of f.
The balance moving towards the right, discharging roller c comes in contact with spring r on lever o, pushes it until it banks at the further side - unlocking then commences; tooth u escapes detent of anchor escape-wheel, moving tooth t, quits pallet f, opposite tooth lifts pallet g, thus arming the other maintainer, and escape-wheel locks on othr detent of anchor; meanwhile, f k being free to fall, impels the balance by finger d, which had just arrived in front of it as the train escaped, and all the parts assume the position shown in fig. 1.
The same explanation applies mutalis mutandis to fig. 1.
Plate 1, Fig. 1
Plate 1, Figs. 3, 4, 5, and 6
Plate 1, Fig. 2
IN MELVINE'S 2 (figs. 1 to 8, plate 2), the balance is entirely free from any connection with the train. The maintainer is the spring e (pulling in the direction of the arrow, figs. 4, 5, 6) actuating lever j on the arbor of which are three fingers i, q, and g. q serves to unlock the re-winder a by lifting detent d (seen in side view, fig. 8), the re-winder arms the maintainer through the medium of i, and g receives the tension of spring e through the cross-bar f. The impelling lever j is always found by the ruby pin l in the position shown in fig. 1. It is kept in that position by g being past the line of centre (fig. 5).
Plate 2, Figs. 5 and 7.
Plate 2, Fig. 4.
Plate 2, Fig. 6.
Fig. 2 show the maintainer having given impulse to the balance, and out of connetion with it, unlocking the train by g lifting detent tooth d.
Tooth t of the re-winding wheel falling against arm i brings back the maintainer to its normal position, as in fig. 1. Arm g being taken bast the line of centres, cross-bar f rests on the collet b, and so all the parts are at rest for a fresh impulse.
When the balance returns it only pushes aside passing spring n, but moving in the direction of arrow (fig. 2), ruby pin l, pulls the maintainer over a little, owing to the passing spring being banked at p (fig. 4). Spring c [sic] being now free pulls the lever over and gives impulse.
Plate 2, Fig. 1
Plate 2, Fig. 2
[Note: I can't seem to find Fig. 3 on Plate 2.]
Plate 2, Fig. 8.
BREGUET'S detached constant-force escapement (shown in figs. 9 and 10, plate 2, and fig. 11), for a balance, is his pendulum one, described page 4, adapted to the altered circumstances. G is the maintainer (and the maintaining spring and the impulse lever are here in one), always pressing in the direction of the arrow; it is locked up by a hook at p, under the detent N (see fig. 11), and it is unlocked by the discharging roller of the balance staff K, as in the ordinary chronometer escapement.
The re-winder is the epicycloidal-toothed wheel D fixed on the arbor of the train wheel B B.
The train is locked by the fly v i under this detent F (see fig. 11), and is unlocked by the end of the maintainer G falling against the end of the detent as shown in fig. 9.
In fig. 10, the balance having just unlocked maintainer G by the discharging roller pushing aside detent N, G therefore gives impulse on the pallet, and their connection having ceased it knocks against detent F and releases fly v i. The train runs on a space, and re-winds the maintainer back to its place under detent N.
On the return vibration the balance merely pushes aside the passing spring H.
Plate 2, Fig. 9.
Plate 2, Fig. 10.
[Drawing in text] Fig. 11.
MASSEY'S 3 (fig. 12). - The impulse given to the balance roller e is entirely derived from the spiral spring o o through the impulse wheel m m, which rides on the arbor of the train wheel l l; the outer end of o o is attached to one of the spokes of the train wheel l l, and the inner end to the collet of the impulse wheel m m.
The train is locked by the pins of the bar f f fixed on the arbour of pinion p.
The balance moving in direction of the arrow, the ruby pin on the roller enters the fork of lever h i, and pushing it, lets the pin on f f escape and rest on another stop at h; when the balance returns, and h i is moved back, the pin of hte bar escapes under h, f f makes half a revolution and locks on outer top of h, tensing spring o o, which gives impulse to the balance by one of the teeth of m m, falling on the impulse pallet.
[Drawing in text] Fig. 12.
1 Society of Arts' Transactions, Vol. 46, page 54, plate 2.
2 Society of Arts' Transactions, 1828, Vol 46, page 58, plate 3.
3 [Presumably UK patent] Specification, No. 3584, A.D. 1824.
HTML markup by David M. MacMillan