US135929A - Improvement in the manufacture of car-springs - Google Patents

Description

N). MIDDLETON & A. M iDDL ETUN, Jr.

Man ufac tu re pf Car-Springs.

N0 135,929. Patented Feb.18,1873.

AM. PHOTO'LII'HUB/PAPH/C 60 NM (DSBOHNES Fiencass;

UNITED STATES- PATENT OFFICE.

NATHAN MIDDLETON AND ALLEN MIDDLETON, JR, OF PHILADELPHIA, PA.

IMPROVEMENT IN THE MANUFACTURE OF CAR-SPRINGS.

Specification forming part of Letters Patent No. 135,929, dated February 18, 1873.

10 all whom it may concern.

Be it known that we, NATHAN MIDDLETON and ALLEN MIDDLETON, J r., of Philadelphia, Pennsylvania, have invented an Improvement in Oar-Springs, of which the following is a either of iron wire or of tempered steel. In carsprings having iron-wire spirals as an elastic medium, dependence has been placed upon a large number of such spirals in each spring, the wire of .each spiral being of small diameter, three sixteenths of an inch or thereabout, but in applying these springs'they were generally limited to freight-cars owing to their restricted elasticity, In making car-springs containing steel spirals, the practice has been to coil heated rods of steel of from one-quarter of an inch to half an inch in diameter, and then harden and temper the spirals, a process both tedious and expensive, for,independent of the necessary manipulationwhich it demands, it is a diflicult matter to impart a uniform degree of temper to the spirals, many of them proving to be defective on bein g properly tested, and others, apparently perfect, beinglikely to break under the repeated shocks and strains to whichthey are subjected when applied to railway cars.

After many experimental tests we have found that a car-spring possessing the desired permanent elasticity can be made with an elastic medium consisting of untempered spirals of cold-drawn or cold-rolled steel, the cold-rolling or cold-drawing-so condensin g the fibers of the metal as to impart a toughness to the same which cannot be acquired by the usual process of hardenin g and tempering. The

cold-drawn rod is coiled in a cold state, so

. It is immaterial how many spirals are used in each spring, for the size of the spirals and their number will depend in a great measure whether the spring has to be used as a bumper, draw, bolster, or bearing spring; nor is it material how the coils are retained in groups so as to constitute a self-contained spring.

It may be remarked that in manufacturing the spirals we prefer to make the coils wide apart in thefirst instance, and afterwards to bring them closer together by compression.

We prefer to use Bessemer steel owing to its tough nature, but there is other steel of analogous character, which can be cold-drawn or cold-rolled, and can be bent while cold into the desired spirals, which form a most efficient and economical elastic medium for carsprings.

We claim as our in vention The improvementdescribed in car-springs and in the manufacture thereof-that is to say, a spring composed of a number of spirals of Bessemer or homogeneous steel wire, colddrawn or cold-rolled, and coiled while cold, as herein set forth.

In'testimony whereof we have signed our namesto this specification in the presence of two subscribing. witnesses.

NATHAN MIDDLETON.

ALLEN MIDDLETON, JR. Witnesses: WM. A. STEEL, HUBERT HoWsoN.

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