Treatise on Clock and Watch Making, Theoretical and Practical

📕 This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1826 edition. Excerpt: ...of the light semi-cylindrical pallet A, and here the time of rest commences; on its return, the face of the pallet presenting itself, gets, in its turn, new impulse, which is communicated to the balance, and so on. C D, No. 2. is a view of the bottom of the crown-wheel. In Kendal's 'scapement, at K, No. 3. a few of the teeth of the two crown-wheels W W, are represented; a tooth of the wheel, on the right hand side, is seen just escaping from the face of the pallet pp, after having given impulse to it, and a tooth of the wheel on the left hand falls that instant on the semi-cylindrical pari, and rests there until the return, when the face presenting itself, it, on that side, gets impulse in its turn, and so on. The free or detached 'scapement is that in which the greater part of the vibrations of the balance is free and independent of the wheels, the balance-wheel being then locked; when unlocked, it gives impulse, which only takes place at every second vibration. In Mudge's detached 'scapement, the impulse is given at every vibration. The progress which has of late years been made in improving the detached 'scapement has been wonderful, when we consider, that half a century ago, the name of this 'scapement was unknown. The first rude draught of any thing like it, appears to be that of Thiout's, described at page 110 of the first volume of his Work, and shown in Plate XLIII. Fig. 30. which he calls, "a 'scapement of a watch, the half of whose vibrations appear to be independent of the wheel work during the time they are made." "The hook B, or detent, as it would now be called, detains the 'scapement wheel for a short while; sec Plate X. No. 54. the balance, in returning, carries with it the pallet A, and consequently...