US347271A - Manufacture of watch-balances - Google Patents

Description

(No Model.) 2 Sheets-Sheet 1.

G. E. HUNTER.

MANUFACTURE OF WATCH BALANCES.

' N07 347,271. Patented Aug. 10, 1886.

2 Sheets-Sheet 2.

(No Model.)

G.E.H UNTER. MANUPAGTURB 0P WATGH BALANGES.

No, 347,271. Patented Aug. 10, 1886.

' PETERS. PhawLixho m hur, Washington. DJ;

UNITED STATEs GEORGE E. HUNTER,

PATENT rrrcno OF 'ELGIN, ASSIGIN OR TO THE ELGIN NATIONAL \VATOH COMPANY, OF CHICAGO, ILLINOIS.

MANUFACTURE OF WATCH-BALANCES.

SPEQIIICATIQN forming part of Letters Patent No. 347,271, dated August 10, 1886.

Application filed March 4,1386. Serial No.194,005. (N'o model.)

To all whom it may concern:

Be it known that I, GEORGE E. HUNTER, of Elgin, in the county of Kane, and in the State of Illinois, have invented certain new and useful Improvementsin \Vatch-Balances; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, in which- Figure 1 is a perspective view of the steel and brass parts of the rim-blank before being united. Fig. 2is alikeviewof the same when joined together. Fig. 3 is a perspective view of said rim-blank dressed to size and prepared I 5 for the reception of peripheral adj usting screws. Fig. 4 is a like view of a rim cut to length and bent to shape. Fig. 5 is a perspective view of the central portion or spider of the balancewheel. Fig. 6 isa like view ofthe completed wheel, and Fig. 7 is a section of said wheel through the plane of its vibration. Letters of like name and kind refer to like parts in each of the figures.

In the construction of watch balances it has heretofore been customary to make the arm and the steel portion of the rim from one solid piece of metal by turning the same into the form of adisk having the desired diameter, then brazing upon its periphery a ring of brass, then turning within one face of said steel disk a recess which in diametercorresponds to the interior diameter of the balance-rim and in depth to the thickness of said rim, less the thickness of the balance-arm, then punching 3 5 from the recessed portion of said disk the surplus metal, so as to leave said arm and rim, then drilling and tapping within said rim the necessary radial holes for the adjustingscrews, then cutting said rim at two opposite points, and, lastly, giving to said divided rim a true circular form. This method of construction is, however, expensive, and the product very inaccurate, as the metalscomposing the balance-rim do not have uniform thickness either jointly or severally throughout their length, and, consequently, there is such unequal expansion and contraction of said rim as to render it impracticable to properly poise the balance forthe ordinary variations in temperature.

The design of my invention is to lessen the cost, to simplify the construction, and to increase the efficiency of watch-balances; and to this end said invention consists in the method employed,substantially as and for the purpose hereinafter specified.

In the carrying ofmy invention into practice a strip of steel, a, having any desired length is drawn through or between polished dies or rollers until it has a uniform thickness, substantially such as is required for the rim of the finished balance, but is slightly greater in width than such rim, Upon one side of the steel strip ais now brazed a strip of brass, a,

which corresponds therewith in length and 6:;

width, but has a slightly greater thickness than is desired in the finished rim, care being taken that said stri s coincide throughout their length, after which the compound strip A is passed through or between spring-pressed 7o rollers or dies, which operate to compress the brass portion a equally throughout its length. The strip A will usually have such length as to enable several balance-rims to be constructed from it, in which event, before said strip is out 7 into the required lengths, the necessary openings,a'",for dowel-pins or rivets, and for adj usting-screws,are drilled at predetermined relative points, and said screw-openings tapped, after which it is passed between mills that operate upon its edges and upon the exposed side of the brass part a, and give to said strip substantially the required transverse dimensions. The compound strip A is now passed between burnishing dies or rollers, which op crate to finish its exposed surfaces, and at the same time remove any unevenness in thickness which may have resulted from the pre ceding operations. The brass portion a being the softer metal, the action of said dies or 0 rollers causes the same to accurately conform to the steel portion a, by which means said parts have jointly and severally a uniform thickness throughout their length, and the grains of the metals are arranged lengthwise 9 5 of the same in parallel lines. The compound strip A, thus constructed, is now out into suitable lengths, and each piece then completed by being passed between polished rollers, which give to the same the proper curvature.

Thewheel-spider or cross-bar B is preferably made by dies from a strip of steel having suf- IOO ficient width, and at each end of the same is formed a lug, I), that is turned upward at a right angle to said bar, and has a length equal to about twice the width of the same at such point. The outer face of each lug is formed upon a curved line, and to it is secured one end of one of the curved rim-bars by means of a screw, 0, aml one or more rivets or dowelpins, 0, which pass radially through the intersecting parts. Said screw projects beyond the periphery, and is threaded; and upon such projecting portion is placed a nut, D, which corresponds in general size and shape to the like features of the heads of adjustingscrews that are placed within the threaded openings (6 between said nut and the free end of said rim-bar. Said nut is preferably split from one end nearly to its opposite end, and such split portion given a slight inward spring, so as to cause it to grasp its screw with sufficient firmness to prevent accidental movement thereon.

Having thus described my invention, what I claim is- 1. As an improvement in the construction of watclrbalances, the method employed for forming the rim -sections, which consists in combining two straight bars of steel and brass by brazing, and then giving to the compound bar the required curvature by means of rollers, substantially as and for thepurpose specified.

2. As an improvement in the construction of watch-balances, the method of forming the rim-sections, which consists in brazing to gether two bars of steel and brass, and then compressing the brass between rollers until it has the required density, substantially as and for the purpose shown.

3. As an improvement in the construction of watch-balances, the method employed for forming the rim-sections,which consists, first, in uniting by brazing twostraight bars of steel and brass, next forming in such compound bar threaded openings for the reception of adjustingscrews, and, lastly, passing said bar through or between rollers and giving to it the required curved form, substantially as and for the purpose set forth.

4. The method employed for constructing watch-balances, which consists in forming each ofthe rim-sections from straight bars of metal brazed together, then curving such eompou ml bar by rollers, and, lastly, securing one endot' said bar-section to or upon the central portion or spider, substantially as described.

5. The method employed for constructing watch-balances, which consists, first, in forming each of the rinrsections from straight bars of metal brazed together, next in forming in such compound bar threaded openings for the reception of adjusting-screws, next in passing said bar through or between rollers and giving to it a curved form, and, lastly, securing one ofits ends upon the spider of the wheel, substantially as specified.

In testimony that 1 claim the foregoing I have hereunto set my hand this 28th day 01' December, 1885.

GEO. E. HUNTER.

.Vi tn esses:

\V. P. HEMMENs, W. H. CLOUDMAN.

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