US953041A - Method of producing tapers in metal. - Google Patents

Description

L. S. LAGHMAN. METHOD OF PRODUCING TAPERS IN METAL. APPLICATION FILED rmm, 190a.

Patented Mar. 29, 1910.

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ATTORNEYS L. S. LAGHMAN.

METHOD OF PRODUCING PAPERS IN METAL.

APPLICATION FILED PEB.8, 1908.

953,041. Patented M31229, 1910.

. 2 SHEETB-SHEET Z.

' ATTORNEY S.

PATENT OFFICE.

LAURENCE sYLflvA LACHMAN, or NEW YORK, N. 2.. ASSIGNOR T UNIVERSAL ELEC- rma wnmruqoomrany, or NEW YORK, is. Y., A CORPORATION or NEW YORK.

-T0 iZZ' whom 'it may concern:

.Methods of Producing Tapers in 'Metal, of

which the following'is a specification.

-The present invention relates to the process of tapering awrod, bar or other piece of metal to a pointby heating a section of metal. to render the same plastic and then applyingstretching or pulling force.

e The special :object of the inventlon 1s,

among other things, to insure the production of a perfectly finished point.

Another "object is to obtain, from asingle bar, rod or piece of metaljmtwo tapered pieces which shall be of identical taper.

The invention consists. substantially in heating the piece .of metal :toplasticity by passing a heating. current of electricity through the same and thennstretching or pulling the, metal of the heated. section to taper the samedown tea-point, the cutting off of flow of heating current and the-rate of drawingor pulling being so controlled that at the instant of separation the metal will be at a comparatively low temperature.

The invention consists further in stretching or pulling the metal equally in opposite directions to maintain, the position of that portion of the metal which is of smallest section, as hereinafter more particularly de-' scribed.

The invention further consists inthe methods or processes andv constructions of apparatus especially adapted for conducting such processes as hereinafter more particu-' larly described and then recited in the claims.

In the accompanying drawings, Figure 1 is a side elevation of an apparatus that may be used in carrying out my invention. Fig. 2 is 'aplan of the-same and illustrates more directions. Fig. 3 shows the two similar pointed pieces resulting from the appllcatlon H j l Specification of Letters I atent. AppHoa/cionflled February 8, 19oz. Serial No. 414,929.

5 meager) 'o'rrnonuome [PAPERS IN METAL.

Patented Mar. 29,1910.

of the process to a single rod, baror pieceof metal.

1 Referring to the drawings, 1, 1" indicate the guides for two platens or slides 3, 3 mountedupon and electrically joined to the terminals" of the secondary 2 of a transformer which supplies heating current to said platensan'd to the clamp-holding blocks mounted on the latter. The platens l may be attached to flexible terminals of said secondary or may'slide in contact with the terminals thereof as well understood in the art.

4 indicates the primary of the transformer and 5 is theline of separation or gap between the secondary terminals usually existing in this type of apparatus, so that the opposite work-holders or clamps on the clamp blocks 3-, 3 will be located, respectively, at opposite sides of the gap and the heated section of work will beopposite said up.

Operating levers for tie clamping devices are indicated at 6, 6, while 7, 7 indicate the usual clamping jaws adapted to engage and firmly hold the section of work, as usual in the art of electric welding.

The piece of metal which is to be reduced or tapered to a point is indicated at 8, while the two separate pointed pieces resulting from the operation are indicated at 8, as shown in Fig. 3.

Incarrying on the process according to my present invention, the bar or rod 8, if it be desired to" form two identical similar pointed pieces from it, is clamped in the jaws of the apparatus so that its medial line will coincide practically with the line -5. If it be desired to produce two pieces of different lengths, the bar 8 would be shifted so the amount of rearward projection of the ends of the bar would be greater or less as desired. The heating electric current is then turned on, thus bringing the section'of metal between-the clamps to a plastic condition, a proper plasticity in the case of high carbon steel being shown by the color being a cherry red. In the case of softer metals, not so high a temperature would be required. When the metal has reached a proper degree of plasticity, a gradual stretching or pulling force is ap lied to the heated section, preferably, t rough the clamps by which the heatlng current is conducted into the work and preferably by moving both clamps in opposite directions away from one another, thus startin a double taper toward the center, but be ore or ractically as soon as the ulling operation gins the fiow of the heating current is preferably entirely stopped, thus avoiding the liability to rupture of the heated section before it has been drawn down to a point. The rate of pulling is so graduated that at the final stage of rupture the metal will be at acomparatively low temperature, thereby roucing anexceedingly fine sharp oint. or the best results the metal shou d be permitted to cool so far that at the instant of rupture and immediately before rupture it will have resumed approximately its natural color or willhave lost its appearance of in candescence. Such a double motion may be roduced by the mechanism to be presently described and is, preferably, an equal motion of both clamps or holders, so that the portion of heated metal of smallest section will be maintained incoincidence with the line 5 'of the gap in the transformer secondary. By this means the two tapers of equal degree are secured, whereas, if the motion were given to one clamp only, so as to carry the most reduced portion of the heated section to one side of the line 5, the tapers of the two portions would he of different degrees. As the tapering progresses and approaches the final stage of rupture of the metal, at which stage in the operation the metal is at a lower temperature owing to the electric current having been cut oil previously to this sta e being reached, the rate of movement 0 the clamp or clamps, in ap alying the stretching or pulling force, is pre .erably slowed down. The point at which the current should be cut oil, in order to insure the proper degree of cooling when the end of the na l stage is reached, can be varied within limits and also the extent to which the drawing action is slowed down, but after the metal has been brought to the desired degree of plasticity, the surest way is to cut off the current immediately and before or coincidently with the beginning of the. drawing or pulling operation.

In Fig. 2 the metalv is shown at the termination of the final stage, which is practically coincident with the rupture of the metal at a section of such minute extent that, in the finished pieces, the taper will terminate in an extremely fine and well finished point, which, in the case of tool steel, can be made superior in finish and sharpness to anything that can be produced by an ordinary swaging operation.

The process can be applied to metal of any cross section and may be used for producing an edge on a properly shaped piece of metal, said edge being, geom'etricall considered, a series of points. In my 0 aims, therefore, while I use the term point it is to be understood that the invention includes the drawing down or tapering of a piece of metal into a sharp edge.

The equal opposite movement of the two holders may be secured by any mechanism properly connected up, an exam le of which 15 shown in Fig. 2 wherein the c amping devices are shown in section. In this figure, 9 is the operating handle pivoted at 10 and connected by a link 11 with one of the clamp supporting blocks or platens, so that, by operating the handle in the direction of the arrow, tension or stretching or pulling force may be applied to the heated section. The extension of the operating handle is connected by a pin with lever 12 and the latter is positively connected by a connecting rod 13 to the opposite holder of its operating mechanism, throu h an intermediate lever 14 and link 15. fiy means of this connecting rod and intermediate lever connecting the holders a movement of said holders away from one another in opposite directions and at an exactly uniform rate is insured under all conditions.

What I claim as my invention is:

1. The improved method of tapering metal to a finished point consisting in passing a heating current of electricity through a section of the metal until the same assumes plasticity, stretching or pulling the metal, and cutting off the flow of current controlling the rate of pulling, so that at and near the final stage at which rupture takes place the metal will be at a comparatively low temperature.

2. The herein described method of tapering metal to a point consisting in heating a section of the metal to plasticity by passing an electric current through the same, and drawing or pulling the metal and graduating the rate of pulling as the metal reaches the final stage of rupture, so that at and near the point of rupture it willhave resumed approximately its natural color.

3. The improved method of tapering metal to a point consisting in electrically heating a section of the metal and stretching or pulling the metal at an equal rate in opposite directions so as to maintain the position of the portion of metal which is of the smallest section in fixed relation to the fixed portion of the structure, as and for the purpose described.

4. In an electric. metal working a paratus, the combination of work-holders adapted to clamp the work at two points located respectively at opposite sides of the heated section thereof, and a rigid system of connecting devices between said holders, whereby any New York and State of New York this 4th movement of separation of one work-holder day of February A. D. 1908. away from the other insures an opposite movement of the other work-holder at an LAURENCE SYWAN LACHMAN' 5 exactly uniform rate, as and for th purpose Witnesses:

described. Y O. F. TISCHNER, Jr.,

Signed at New York in the county of LILLIAN BLOND.

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