Watch and Clock Escapements

e moon and stars by night served to warn him of the recurring periods of light and darkness. By noting the position of these stellar bodies during his lonely vigils, he soon became proficient

these occupations should be instituted, and with this end in view he contrived, by means of burning lights or by restricting the flowing

derable number of escapements have been invented and made up, both for clocks and watches; only a few, however, of the almost numberless systems have survived the test of time and been adopted in the manufacture of the timepiece as we know it now. Indeed, many such inventions never passed the experimental stage, and yet it would be very interesting to the professional horologist, the apprentice and even the layman to become more intimately acquainted with the vast variety of in

S TO BE

hat means the procession of the wheel-work and, as a consequence, of the hands thereto attached. At first blush it seems as if a continually-moving governor, such as is in us

the procession of the wheel-work, and thereby gaining a periodically uniform movement. Whatever may be the system or kind of escapement employed, the functioning of the mechanism is characte

THE MOST ES

e which should perform its duty with the least influence upon the time of oscillation or vibration of the regulating organ. The stoppage of the train by the escapement is brought about in different ways, which may be gathered under three heads or categories. In

e name of recoil escapement. It was recognized by the fraternity that this recoil was prejudicial to the regularity of the running of the mechanism and, after the invention of the pendulum and the spiral, inventive makers succe

egulating organ. This latter performs its vibrations of oscillation quite without interference, and it is only in contact with the train during the very

The cylinder and duplex escapements for watches and the Graham anchor escapement for clocks are styles of the dead-beat escapement most often employed. Among the detache

GE ESCA

y in construction. We regret that the world does not know either the name of its originator nor the date at which the

ud, in his "History of the Measurement of Time," says of the balance-wheel escapement: "Since the epoch of its invention an infinite variety of escapements have been constructed, but the one which is employed in ordinary watches for every-day use is still the best." In referring to our illustrations, we beg first to call attent

from the tooth d be forced back by the momentum of the pallet, that is, suffer a recoil; but on the return journey of the pallet P', the tooth e will then add its impulse to the receding pallet. The tooth e having thus accomplished its mission, will now slip by and the tooth c will come in lock with the pallet P and, a

ENT OF A CROWN-

wo arms, B and B, called adjusters, forming the balance. Two small weights D D, adapted to movement along the rules or adjusters serve to regulate the duration of a vibration. In Fig. 148 we have the arrangement adopted in small timepieces and watches: B represents the regulator in the form

itself a regulating force, could not possibly give forth anything else than an unsteady movement. However, mechanical clocks fitted with this escapement offer indisputable advantages over the ancient clepsydra; in spite of their imperfections they rendered important services, especially after the striking movement had been added. F

'S EXPE

he oscillation an absolute generality of isochronism, which they did not possess; nor did he know how to apply his famous discovery to the measurement of time. In fact, it was not till after more than half a century had elapsed, in 1657, to

and the fact, the honor of the discovery was lost to him by the laziness and negligence of his pupil, Viviani, upon whom he had placed such high hopes. One thing is certain, that the right of priority of the discovery and the recognition of the entire world has been incontestably bestowed upon Huygens. The escapement which Galileo is supposed to have conceived

e cord, received the impulses through the intermediation of the forked arm F, which formed a part of the verge. At first this forked arm was not thought of, for the pendulum itself formed a part of the verge. A far-reaching step had been taken, but it soon became app

T OF ISOCHRON

a greater impulse, the pendulum would thus be shortened and the shortening would correct the time of the oscillation. However, the application of an exact cycloidal arc was a matter of no little difficulty, if not an impossibility in practice, and practical men began to grope about in search of an escapement which would permit the use of shorter arcs of oscillation. At London the horologist, G. Clement, solved the problem in

O-PENDULUM

and a segment of a toothed wheel D D, which produces the effect of solidarity between them. The two pendulums oscillate inversely

he cycloidal curves and are placed with a view of correcting the inequality in the duration of the oscillations. In watches the circular balances did not afford any better results t

h a straight and very flexible spring, which later was supplanted by one coiled up like a serpent; but in spite of this advancement, the watches did not keep much better time. Harrison, the celebrated English horologist, had recourse to two artifices, of which the one consisted in giving to the

ULARITIES IN THE

f which was fixed a pinion D. By this method he obtained extended arcs of vibration, but the vibrations were, as a consequence, very slow, and they still remained subject to all the irregularities arising from the variation in the motive power as well as from shocks. A little later, but about the same epoch, a certain Dr. Hook, of the Royal So

tooth a of the escape wheel exerts its lift upon the pallet P'; when this tooth escapes the tooth b will fall upon the pallet P' on the opposite side, a recoil will be produced upon the action of the two united balances, then the tooth b will give its impulse in the contrary direc

alileo, in the application of the pendulum, to have priority in the idea. Huygens, who had discovered and corrected the irregularities in the oscillations of the pendulum, did not think of thos

HAT CREATED MU

, no other escapement but the recoil escapement was possible; a new highway was thus opened to the searchers. The water clocks (clepsydr?) and the hour glasses disappeared completely, and the

toward the one goal, viz.: the perfecting of the verge escapement; but practice demonstrated that no other arrangement of the parts was superior to the or

he other, by means of the arms o o'. One of the axes carries besides the fork F, which transmits the impulse to the pendulum B. In the front view, at the right

rying the two pallets is pivoted in the vertical diameter of the larger wheel. The front view shows the modus operandi of this combination, which is practically the same as the others. The tooth a of the large wheel exerts its force upon the pallet P, and the tooth b of the ratch

AT SOLUTION OF A

eing turned in the opposite direction by its comrade. Both are furnished with pins c c', which act alternately upon the pallets P P' disposed in the same plane upon the verge V and pivoted between the wheels. Our drawing represents the escapement at the moment when the pin C' delivers its impulse, and this having

of the lever P, is fixed a fork which communicates the motion to the pendulum. The two levers are intimately connected by the two arms B B', of which the former carries an adjusting screw, a well-conceived addition for regulating the opening between the pallets. The counter-weight C co

MODIFI

he piece B B' which thus receives the impulse from the wheel R. Two adjusting screws serve to place the escapement upon the center. By degrees these fantastic constructions were abandoned to make way for the anchor recoil escapement, which was invented, as we have said, in 1675, by G. Clement, a horologist, of London. In Fig. 164 we have the disposition of the parts as first arranged by this artist. Here the pallets are replaced by the inclines A and B of the anchor, which is pivoted at V upon an axis to which is fixed also the fork. The tooth a escapes from the incline or lever A, and the tooth b immed

precise rating. Thus, in 1720, Julien Leroy occupied himself working out the proper shapes for the inclines to produce this desired isochronism. Searching along the same path, Ferd. Berthoud constructed an escapement represented by the Fig. 165. In it we see the same inclines A B of the former construction, but the lockin

LE ESCA

oints of the anchor more easily. Under the name of the English recoil anchor there came into use an escapement with a reduced gable, which embraced fewer teeth between the pallets or inclines; we give a representation of this in Fig. 167. This system seems to have been moderately successful. The anchor recoil escapement in use in Germany to-day is demonstrated in Fig. 168; this arrangement is also found in the American clocks. As we see, the anchor is composed

o distance and curvature, the counterpart of Fig. 168. At the moment of impact their extreme ends recoil or spring back from the shock of

It is pivoted at V and is capable of a very rapid oscillatory motion, the arc of which may, however, be fixed by the stud or stop D, which limits the swing of the fly C. This fly is of one piece with the lever and, together with the stud D, determines the angular motion of the