150 



HOROLOGY. 



Repeating 



vvtche. 



Fig. 4. 



er which is called the dial or motion work. It is seen 

 ; n th e instant where the button or pendant is just push- 

 ed home to make it repeat. In first taking off the hands, 

 a* 1 *! tnen tne screw which fixes tlie dial of repeating 

 watches, we will see the same mechanism that this Fi- 

 gure presents. This is the kind of repeating motion 

 work most generally adopted ; it is solid, and of easy 

 execution. P is the ring or bow to which the pendant 

 shank or pusher is attached, and this enters into the sock- 

 et O of the watch case, and moves within it its whole 

 length, in tending towards the centre. It carries the 

 piece p, which is of steel, and fixed in the pendant shank, 

 both composing the pusher; the under side is filed flat. 

 A plate of steel fixed to the case inside, prevents it from 

 turning round about, and permits it to move length- 

 wise only. The end part of the steel in the pusher is 

 formed so that it cannot come out of the case socket, 

 this being also prevented by the small steel plate. 



The end of the piece p acts on the heel I of the rack 

 CC, whose centre of motion is at y, and at whose ex- 

 tremity c, is fixed one end of the chain s s. The other 

 end keeps hold of the circumference of a pulley A, put 

 by a square on the prolonged arbor of the first wheel of 

 the runners. This chain passes over a second pulley B. 

 If, then, we push the pusher P, the end c of the rack 

 will describe a certain space, and, by means of the 

 chain s s, will cause the pullies A, B to turn. The 

 ratchet R (Fig. 4.) will also retrograde, until the arm 

 b of the rack comes upon the snail L ; then the main 

 spring of the repetition bringing back the ratchet, 

 and the pieces which it carries, the arm m will present 

 itself to the teeth of the ratchet, and the hammer M 

 will strike the hours, of which the quantity depends on 

 the step of the snail, which is presented to the arm b. 



In order to have a better idea of the effect and dis- 

 position of this repetition, it is only necessary to look at 

 Fig. 4. where the rack y c is seen in perspective ; the 

 hour snail L, and the star wheel E ; the pullies A and 

 B, the ratchet R, the wheel a, the part of raising m n 

 of the hour hammer ; and these are the principal parts 

 of a repetition, which are drawn as if they were in 

 action. 



The snail L is fixed to the star E by means of two 

 screws ; they both turn on the pivot formed from the 

 screw V, carried by the all or nothing piece TR, move- 

 able on its centre T ; the all or nothing piece forms 

 with the plate a sort of frame, in which the star and 

 hour snail turn. Let us now see how the quarters are 

 repeated. 



Besides the hour hammer M, there is another N, 

 (Plate CCCVI. Fig. 1 .), whose arbor or pivot comes up 

 within the motion work, and carries the piece 5, 6 ( Plate 

 CCCVI. Figs. 3, 4.) The prolonged pivot of the hour or 

 great hammer passes also within the motion work, and 

 carries the small arm q : these pieces 5, 6 and q serve 

 to make the quarters strike by double blows. This is 

 the effect of the quarter rack Q, which has teeth 

 at the ends F and G, that act on the pieces q, 6, 

 and cause the hammers to strike. This piece or rack 

 Q is carried about by the arm k, which the arbor of the 

 ratchet R has on it, by a square above the pulley A, 

 in such a manner, that when the hours are repeated 

 the arm k acts on the pin G fixed in the quarter rack, 

 and obliges it to turn and raise the arms q and 6, and 

 consequently the hammers. 



The number of quarters which the hammers must 

 strike, is determined by the quarter snail N, according 

 to the depth of the steps /;, ] , 2, or 3 which it presents : 

 the quarter rack Q, pressed by the spring D, retro- 

 grades ; and the teeth of the rack engage more or less 



with the arms a, 6, which get aUo a retrograde motion, 

 and are brought back by the springs 10 and .9: The 

 arm k bringing back the quarter ruck, its arm m acts 

 on the extremity R of the all or nothing TR, the v 

 opening of which at .r, traversing against a stud fix- Figs.': 

 ed lo the plate, allows 11 to describe a small space : 

 the arm m, comingto the extremity of R, this last pressed 

 by the spring i x, is made to return into its place, 

 so that the arm m rests on the end R, and by this 

 the quarter rack cannot fall or retrograde, unless the 

 all or nothing piece is pushed aside. The arm u, car- 

 ried by the quarter rack, serves to overturn or set 

 aside the raising piece m, (Fig. 4.) (which is moveable 

 on the arbor of the hour hammer,) whose pin 1, comes 

 up within the motion work ; so that when even the 

 hours and quarters are repeated, the quarter rack still 

 continues to move a little way, and the arm u turns 

 aside the raising piece m, by means of the pin 1, 

 which comes within the motion work, and by this it 

 is put from having any holding with the ratchet R, so 

 long as the all or nothing TR does not allow the quar- 

 ter rack to retrograde or fall ; which can only happen 

 in the case when, having pushed home the pendant 

 against the snail, the arm l> of the rack CC presses the 

 snail, and makes it describe a small space, at the ex- 

 tremity R of the all or nothing : then the quarter rack 

 will fall and disengage the bees or lifting pieces, and 

 the hammers will strike the hours and quarters, given 

 by the snails L and N. 



The great hammer carries a pin 3, Fig. 4. which 

 comes up to the motion work through an opening 

 marked 3, Fig. 3. : the spring r acts on this pin, and 

 causes the great hammer to strike : this hammer carries 

 another pin 2, which passes also through to the motion 

 work by an opening 2, Fig. 3. ; it is upon this that the 

 small tail of the raising piece q acts, to make it give 

 blows for the quarters : the small hammer has also a 

 pin which passes through to the motion work by the 

 opening 4 ; it is upon this pin that the spring 7 presses, 

 to cause the quarter hammer to strike. The spring S is 

 the spring jumper, which acts on the star wheel, E. 



Figure 6. represents the cannon pinion and the quar-< i 

 ter snail N, seen in perspective. The quarter snail N 

 is rivetted on the cannon pinion c, the end of whicli 

 D carries the minute hand ; this snail N carries the 

 surprise S, the effect of which is the same as that 

 for the repeating clock ; that is to say, when the pin 

 O of the surprise shifts the place, or causes the star to 

 advance, and the jumper having done turning it, one 

 of the teeth of the star comes to touch the pin O which 

 is carried by the surprise, and causes the part of the 

 surprise Z, Fig. 3. to advance, so that when the arm Q 

 of the quarter rack falls on this part Z, and prevents it 

 from falling on the step 3 of the snail; by this the piece 

 repeats only the hour. The changing from one hour to 

 another is by this way made in an instant, and the 

 watch strikes the hour exactly as marked by the hands. 

 The socket or cannon of the cannon pinion cD, Fig. 6. is 

 slit, in order that it may move spring tight on the ar- 

 bor of the second wheel, on which it enters with a de- 

 gree of stiffness or friction, slight enough to be able to 

 turn easily the minute hand to either side, by setting 

 it back or forward according as it may be required, 

 which sets also the hour hand to the hours. 



It is proper here to undeceive those who think that 

 they injure their watches in setting the minute hand 

 backward. In order to convince one's self that there is 

 nothing in this, it is sufficient to remark the position 

 which the pieces must have in a repeating motion work, 

 when it has to repeat the hour, when the pendant or 



