US2507698A

US2507698A - Hairspring

Info

Publication number: US2507698A
Application number: US5690A
Authority: US
Inventors: Dubois Ernest
Original assignee: Individual
Current assignee: Individual
Priority date: 1947-02-12
Filing date: 1948-01-31
Publication date: 1950-05-16
Anticipated expiration: 1967-05-16

Description

Patented May 16, 1950 UNITED STATES FATENT OFFICE N Drawing. Application January 31, 1948, Serial No. 5,690. In Switzerland February 12, 1947 4 Claims.

The work hitherto done in the province of ferro-nickels for hair-springs has had as its main purpose the endeavour to compensate for differences of running which are due to variations of temperature, as exemplified by Swiss Patents Nos. 14,270, 15,526, 15,527, 54,876, 82,081 and 89,576.

Temperature variation is not however the sole cause of running faults of Watches; variation of position from horizontal to vertical (flat to hung, according to the terms used by watch makers) occasions very considerable disturbances, which are due, among other things, to the escapement itself, to the different friction of the pivots, etc. To these disturbances are also to be added the lack of isochronism of the oscillations of the hair-spring and balance assembly, the amplitude of which is less in the vertical position than in the horizontal position. The hairsprings offer in fact an extremely serious defect when the oscillations are not isochronous and depend upon the amplitude.

The purpose of the present invention is to provide a solution of a metallurgical order for this difiicult problem. This solution will be complete only if it conserves the properties of thermal compensation.

The compensating hair-springs used at present, consisting of austenitic ferro-nickels hardened by simple or complex carbides, all give, in the horizontal position, a loss of 8 to 25 seconds per day between the speed when the watch has just been wound-up and the speed after 24 hours, when the spring is relaxed and the amplitude of the oscillations is reduced.

Now, it has recently been found that it is possible to adjust the isochronism of such a hairspring at will, or even to modify it in the sense of a slight advance in the small oscillations, if the alloy comprises an addition of columbium (or niobium). This addition is already distinctly perceptible at an amount of 0.1%, but it becomes energetically effective in amounts of 1 to Columbium does not entail the manufacturing difiiculties which have been occasioned by all the additions previously tried in the attempts to correct the loss of time in the small arcs of the carburised compensating ferro-nickels, and which have hitherto rendered this correction impossible.

From 0.1 to 1.5% it enables isochronism to be from 29 to 42% of nickel, from 4 to 10% chromium, from 1 to 5% of tungsten, from 0.1 to 2% of vanadium, from 0.5 to 5% of manganese and silicon together, and from 0.5 to 1% of carbon, the remainder being iron. In certain cases, the vanadium may be omitted.

Suitably proportioned within these limits, such an alloy therefore enables an isochronous and thermally compensating hair-spring to be manufacture'cl or even a hair-spring which, in the small arcs, reveals just the very slight advance which is necessary in order to compensate for the losses of time occasioned. by passing from the horizontal position to the vertical position, while remaining thermally compensating.

A watch provided with a hair-spring of the following composition:

Percent Nickel 29 to 42 Chromium 4 to 10 Tungsten 1 to 5 Vanadium 0.1 to 2 Manganese and silicon 0.5 to 5 Carbon 0.5 to 1 Columbium 0.1 to 5 Iron remainder will be insensitive to variations of temperature and will show no difference of running between the horizontal position and the vertical position.

What I claim is:

1. An isochronically compensated hair spring for chronometers and the like composed of a lferro-nickel alloy containing from 0.1 to 5% of columbium, from 29 to 42% of nickel, from 4 to 10% of chromium, from 1 to 5% of tungsten, from 0.5 to 5% of manganese and silicon together and from 0.5 to 1% of carbon, the remainder being Iron.

2. A spring formed of an alloy according to claim 1, further including from 0.1 to 2% of vanadium.

3. An alloy comprising from 0.1 to 5% of columbium, from 29 to 42% of nickel, from 4 to 10% of chromium, from 1 to 5% of tungsten, from 0.5 to 5% of manganese and silicon, together, and from 0.5 to 1% of carbon, the remainder being iron.

4. An alloy according to claim 3 further including from 0.1 to 2% of vanadium.

ERNEST DUBOIS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,106,207 Guillaume Aug. 4, 1914 1,454,473 Guillaume May 8, 1923 2,373,490 Mohling Apr. 10, 1945

Claims

1. AN ISOCHRONICALLY COMPENSATED HAIR SPRING FOR CHRONOMETERS AND THE LIKE COMPOSED OF A FERRO-NICKEL ALLOY CONTAINING FROM 0.1 TO 5% OF COLUMBIUM, FROM 29 TO 42% OF NICKEL, FROM 4 TO 10% OF CHRONIUM, FROM 1 TO 5% OF TUNGSTEN, FROM 0.5 TO 5% OF MANGANESE AND SILICON TOGETHER AND FROM 0.5 TO 1% OF CARBON, THE REMAINDER BEING IRON.