US374359A - Chakles t - Google Patents

Description

' (No Model.)

. 0. T. HIGGI NBOTHAM.

MAINSPRING BRAGE AND FASTENER FOR WATCHES OR CLOCKS. No, 374.359. D Patented Deo. 6, 1887.

.. T D. STATES PATENT OFFIC THE SETHTHOMAS CLOCK COMPANY, OF SAME PLACE.

MAINSPRING- BRACE AND FASTENER FOR WATCHESAND CLOCKS.

SPECIFICATION forming part of Letters Patent No. 374,359, dated December 6, 1887.

Application filed July 7. 1887.

To all whom, it may concern.- 1

Be it known that I, CHARLtS T. HIG'GFX- BOTHAM, of Thomaston, Litehfield county, and State of Connecticut, have invented a certainnewandusefullmprovementinYVatchesviz., a new and improved mainspring brace and fastener; and I do hereby declare that the following isa full, clear, and exact description of the invention, which will enable others skilled in the art to which it appcrtains to make and use the same, reference being had to the accompanyingdrawings, and to letters of reference marked thereon, which form a part of this specification.

The'object and nature of my invention are to keep the coils of'the mainspring free and apart from each other, and thus'prevent loss and variation of the force of the spring by the friction of its coils, and at the same time to I firmly secure the outer extremity of the mainspring to and within the mainspr'ing box or barrel by a new device and by simpler and more durable means than any heretofore used or known. I

Heretofore the mainspriugs of watches have been generally secured to the barrel by a single hook or stud-pin in the perimeter of the mainspringchamber engaging with a slot in the mainspring, or vice versa. The formation of holes for the studs diminishes the strength of the material at those points to such an extent that it often gives way, as does'the hook or stud itself, when subjected to the severe and sudden strain caused by the breaking of the mainspring or by overwinding it. In mainsprings secured in such manner-,or in any other manner which I have heretofore seen, there is more or less lateral strain, which serves to cant the coils and to make them impinge upon each other or upon the top or bottom and sides of the barrel, thereby causing friction, which weakens the force of the spring and causes a want of uniformity in its act-ion. The following is-a brief description of the accompanying sheet of drawings.

Figure 1 is a front elevation of the,- brace. t 1g. 21s a reverse elevation of the brace. Fig. 3 1s a view of the longitudinal edge of the brace; Fig. 4 is a front view of a section of the mainspriug with the brace riveted thereto on the reverse surface. Fig. 5 is a view of Serial No. 213.520. (x0 model.)

the longitudinal edge of a section of the maiuspring with the brace riveted thereto. Fig.

6 is a top plan view of an uncovered mainspriug-barrel and of a partially-wound mainsprihg in place therein, with my brace and fastener riveted to such spring.

Similar letters of reference indicate like parts in the several figures.

In the figures, A represents the brace; B, a section of the l-nainspring; D D, semi-cylindrical studs, and C a rivet.

My brace can be manufactured froma piece ofsteel of suitable length, breadth, and thickness by milling or cutting away the metal, so as to leave it in the required shape; or, more economically and expeditiously, by swaging and stamping such piece of steel into the required shape by means of dies specially made for that purpose.

My brace, as ordinarily constructed by me,

" onlannss HIGGINBOTHAM, or 'rnonasrox, cosmcmm, ASSIGNOR 'ro for, say, the mainspring of an ordinary eighteen-size watch, consists of a piece of flat steel with semicircular ends about fiveeights of an inch in length, with a body of thcsamebreadth as that of the mainspriug to which it is to be attached, and of about eight one-thousandths half its length, and thence tapering through the other half to aknife-edge, as shown in Fig. 3. Midway, or thereabout, of its length it has two semi-cylindrical steel logs or studs, D D, one on each side edge, extending both of an inch in thickness throughout about oneinward and outward at right angles thereto from two-hundredths to three-hundredths of an inch, and of about double the thickness of the flatsteel at that point. These studs are finished flush with the one surfaceof thebrace, as shown in Fig. 2, while on the other surface, Fig. 1, they appear in semi-cylindrical form. From the latter surface, and midway, or thereabout, between those studs and the butt or thicker end of the brace, there is a cylindrical projection or pin, C, of proper size and length for and to be a rivet for the purpose of riveting the brace A to the muinspring B. Before being so riveted the brace is bent into a segment of a circle, as shown in Fig. 3, corresponding in curve with the interior of the bar- 'rel inwhich tho mainspring is to be placed.

, The brace is next hardened and tempered, and it is then ready to be riveted to the inner side of the outer coil of the mai nspring atsuch point and in such manner as to allow itsouter end to slightly overlap the buttcud of the brace, as shown in Figs. 4 and 5. Recesses or slots are cut at the proper places'in the sides of the Inainspring, and into which are let the "barrel. The studs are greatly strengthened by being extended inward in the form of ribs along thesurfa-ce of the brace. I am aware that watch-spring braces called pivoted braces have been heretofore constructed in square or rectangular form, with cylindrical or semi-cylindriml flanges or studs running across one end thereof and projecting beyond its edges and the edges of themaiuspring,'soas to pass through holesin the top and bottom ofthe mainspring-barrel, and thus to .rctain the mainspri'n'gtherein; but such braces have an apron or portion of the brace extending in only one direction from the studs, and must necessarily" always be riveted to the mainspring at a point after the studs. Braces so constructed and riveted always have the tendency to deflect the coils of the mainspring to unduly separate them on one side of the arbor and to carry them into contact with each other 'on the opposite side, and thus by friction the spring is made to grip or kick, as it is called, in the barrel in the process of unwinding. The are of vibration of the balance is thereby varied, and thus the time of the watch. My brace, on the other hand, has an apron or portion of the brace extending in both directions from the studs, and is riveted to the mainspriug atapointbeforethcstuds-- that is to say, between them and the butt-end of the brace. My brace so constructed and riveted serves to keep the coils of the mainspring uniformly apart from each other while the spring is unwinding, to constantly preserve thesame arc of vibration of the balance, and thus to make the watch keep uniform time. I have also observed that a watch run by means of a. mainspring with my brace attach-ed thereto will not only keep more accu rate time, but run one to two hours longer than the same watch run by means of the same'spring with a pivoted brace, so called, attached thereto.

Having described my'invent-ion, what I claim, and desire to secure by Letters Patent,

1. A iuainspring brace and fastener with one-half tapering to an edge, and with semicylindrieal flanges or studs D D on its sides midway, or thereabout, between its ends, designed to be riveted to the mainspring near its outer end and serving to secure it within the barrel, and to keep its coils uniformly apart, or nearly so,in their winding and operation.

2. A mainspring brace and fastener provided with studs or flanges continued inward a short distance in ribs partly across the surface of the brace, in combination with a. mainspring having recesses to receive such ribs for the purpose of substantially increasing the strength of the studs without displacing the spring or encroaching upon its space within the barrel.

3. The combination, with the mainspring of a watch, of abrace and fastener tapering to an edge and adapted, when riveted to a mainspring nearits outer end, to secure it by means of flanges or studs to and within the mainspring-barrel, and serving also to keep the coils free from each other and to allow them to act without friction or lateral restraint-,all

substantially as set forth, and for the pur-

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