CLOCKS

Clock Old

how much do you know of the clock train?

In ancient, people sketch time is not through caculate the whole day times, but use some clock device to caculate the rest time, such as the famous sandglass, or the big stone such as sundial, it also been called gnomon.

In the early European, they invented the clock, use the complex structure and the surper pendulums to show the time flow, like the century clock in England and so on. But actually few people know the whole history about the clock train.

I suppose therefore that the pendulum in the old Peterborough, and Exeter, and other church clocks were added long after their original construction. Those clocks were wound up by long spikes or handles sticking out of the wooden barrel over which the rope goes which carries the weight. In many old church clocks the weight is only a large stone. It is not until quite modern times that church clocks had minute hands besides the hour ones, but in other respects there is surprisingly little difference in principle between the oldest of these machines and most turret clocks of the present day.

The going part of a clock is, and always has been, nothing but a train of some number of wheels and pinions, of which one turns in 12 hours, and another in 1 hour, if there is a minute hand. The first, or slowest, or ‘great' wheel, is turned by a weight hanging by a rope wound round a barrel on that wheel's axis, or arbor, as it is called in clock-making; and the last or quickest wheel drives a fan-fly, or a fly-wheel, or a pair of vibrating arms, called a ‘balance,' or a pendulum, to regulate the velocity of the train. A spring clock is merely a compound of a large watch and a common clock.

Any one who has looked at the inside of a clock—and it is useless to read this book until you have—knows it consists of a few large wheels with a good many teeth, and that the teeth of every large wheel, except the highest, are engaged in or drive some much smaller wheels fixed on the axes or arbors of all the large ones except the largest. These small wheels are called pinions, and their teeth are called ‘leaves' for distinction. This figure 3 shows a set of pinions of from 6 to 16 leaves, the lowest and the highest numbers used. It also shows the kind of steel plate which is used for drawing pinion wire.

For it is cheaper to make the arbors of such wire, turning off the projections all along the arbor except where they form the pinion itself, than to cut the pinions out of the solid. But they are not so good as cut ones, and I believe are not used in the best clocks.

The largest wheel in the train, which is called ‘the great wheel,' appears to be stuck on the end of the barrel which carries the string and the weight attached to it—whether with a moving pulley or not, does not signify as a matter of principle, which is all we are considering at present. The only effect of the pulley in to take a double string of twice the length of a single one in the same clock case, which enables a larger barrel to be used and also prevents the string from untwisting. 

But if the great wheel were really fixed to the barrel there could be no winding up, except by an endless chain contrivance, which we need not now consider. Accordingly the real arrangement is that the great wheel rides freely on the arbor of the barrel, and is connected with it by a ratchet and click; the ratchet being a saw-toothed wheel on the end of the barrel, and the click being on the great wheel with a spring to keep it in the ratchet teeth, which pass under it in winding, but cannot return, except with the great wheel itself. You will see a picture of it under ‘Maintaining Powers,' farther on in the book.

And it is all the same whether the barrel is turned in the old way by spokes, or in the modern way by a key or ‘winder' put on the squared end of the arbor; only in the former case the barrel rides loose on the arbor, and in the latter is fixed to it and the wheel rides loose. Consequently the weight is always acting on the train, except at the time of winding; and in all good clocks there are contrivances for keeping the force on even then, called maintaining powers. Now suppose the great wheel has 120 teeth, and the pinion which it drives has 10; then if that pinion and its arbor and the wheel stuck on to it turn in one hour, the great wheel will evidently turn in 12 hours.

The wheel which turns in an hour is called the centre wheel in house clocks, because that arbor comes through to the centre of the dial and carries the minute hand. Suppose that wheel has 64 teeth and drives a pinion of 8; then that pinion and the wheel on its arbor will turn in 8 minutes; and if that has 60 teeth and drives another pinion of 8, that pinion and arbor will turn in a minute, and the wheel on that arbor is the scape-wheel, which drives the pendulum vibrating in a second, as we shall see presently. Not that there is any virtue in these particular numbers of teeth and leaves, or that the pendulum need vibrate seconds; most church clock pendulums are slower, and all short spring clock pendulums are faster. All that is requisite theoretically is, that the numbers of the teeth of all the wheels multiplied together, and divided by the numbers of the leaves of all the pinions multiplied together, should give the proper velocity-ratio between the slowest wheel and the quickest.

Thus, if the scape wheel has to turn 60 times as fast as the centre wheel, and there is one between them, which may turn in any time, the product of the teeth divided by that of the leaves must = 60, and subject to that, you may distribute the numbers as you please—theoretically; but practically other considerations come in, such as that the slower wheels must be larger than the quicker ones, or they could not clear the arbors below them; that if the leaves of the pinions are very few they do not drive easily, and if they are many the teeth must be many and small, and more expensive to cut, and so forth; and the result is that, in the common long house clocks the numbers are usually what I gave just now; but in astronomical clocks or regulators they are higher, sometimes twice as much; in turret clocks they vary more, according to circumstances, as will be seen hereafter.

 

About the Author

Graham watches,  Graham Chronofighter Oversize Diver Watches,   Graham Swordfish Watches   

In the Nancy Drew game, Secret of the Old Clock, does Christine Ebersole do the voice of 1 of the characters?

She sounds like the lady with the southern-ish accent that's always on the 1st floor of the lilac inn behind that podeom. Does anyone know?

No, Jane is voiced bySarah Papineau,

http://www.imdb.com/title/tt0808390/

I've noticed many actors that I think sound like the characters from those games ...

"Grandfather's Clock" Annie & Mac Old Time Music Moment

Tags: clock, clock old, clock old south, clock old town square, clock old town square prague, clock old trafford, clocks, design, history, time

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