| Title: | Potence |
| Original Title: | Potence |
| Volume and Page: | Vol. 13 (1765), p. 181 |
| Author: | Unknown |
| Translator: | Charles Ferguson [Colby College, Emeritus] |
| Subject terms: |
Clockmaking
|
| Original Version (ARTFL): | Link |
| Rights/Permissions: |
This text is protected by copyright and may be linked to without seeking permission. Please see http://quod.lib.umich.edu/d/did/terms.html for information on reproduction. |
| URL: | http://hdl.handle.net/2027/spo.did2222.0003.367 |
| Citation (MLA): | "Potence." The Encyclopedia of Diderot & d'Alembert Collaborative Translation Project. Translated by Charles Ferguson. Ann Arbor: Michigan Publishing, University of Michigan Library, 2018. Web. [fill in today's date in the form 18 Apr. 2009 and remove square brackets]. <http://hdl.handle.net/2027/spo.did2222.0003.367>. Trans. of "Potence," Encyclopédie ou Dictionnaire raisonné des sciences, des arts et des métiers, vol. 13. Paris, 1765. |
| Citation (Chicago): | "Potence." The Encyclopedia of Diderot & d'Alembert Collaborative Translation Project. Translated by Charles Ferguson. Ann Arbor: Michigan Publishing, University of Michigan Library, 2018. http://hdl.handle.net/2027/spo.did2222.0003.367 (accessed [fill in today's date in the form April 18, 2009 and remove square brackets]). Originally published as "Potence," Encyclopédie ou Dictionnaire raisonné des sciences, des arts et des métiers, 13:181 (Paris, 1765). |
Potence. In a watch, a stout brass part seen in the cage, sometimes riveted but ordinarily screwed securely and vertically to the plate bearing the cock; it carries the balance verge and one of the pivots of the contrate wheel. See Plate [X, key AA, Figure 44, 1-7; key CC, Figures 8 & 13] [1].
The potence usually has three parts: the tip, the heel, and the inserts. The tip is part r , in which one of the pivots of the contrate wheel turns; the heel , t , is the part in which the lower pivot of the balance verge turns; the inserts are the small parts dovetailed into the tip and the heel. I say the tip because most commonly, instead of a hole, the tip has a small dovetail slot to fit insert n , which in turn has the hole for the pivot; this adjustment is necessary to equalize the drop of the contrate wheel on each of the pallets. See Drop.
The name royal potence has been given to potences designed by M. Le Roy, where the tip , Figure 44 n , is movable in its slot by means of a small key, e , screwed into the body of the potence ; this arrangement eliminates the insert from the tip, and it is much easier to equalize the drop of the contrate wheel than with conventional potences , even when the watch is assembled, a very considerable advantage because it allows setting the beat with the greatest precision. See Drop, Escapement, Watch, etc.
This potence and its various parts are shown in a series of figures, seen as mounted on the plate. The first figure shows it from the side of the potence stud , o ; n is the tip of the insert, t the heel, and e the key used to slide the insert in and out from n to e ; there is a small screw that presses the insert against the potence so that it can move sidewise but can have no play in any direction, which is an absolute necessity. The following two show: first, the insert seen from the front; and second, from the side. The fourth [ sic ] is the key, with a collar in a groove cut into the insert. The three figures, 5, 6, and 7, show the potence from three sides; first, from outside; second, from the opposite end; and the third, from beneath; 22 pla is the heel insert, which must be of tempered steel, hard and carefully polished; the lower end of the balance verge rests on it when the watch is lying on its crystal. See Oiler.
1. The references do not agree with the figures (translator's note).