US1351909A - Method of and apparatus for heat-treating metals - Google Patents

Description

V L. E. JOHNSON.

METHOD OF AND APPARATUS FOR HEAT TREATING METALS.

APPLICATION FILED NOV. 11. 1918.

1,35 1,909, PatentedSept. 7, 1920.

liujenl'or: IawrenceE. Johnson,

LAWRENCE E. JOHNSON, F MELROSE, MASSACHUSETTS,

PATENT OFFICE.

MENTS, TO MATTIE S. JOHNSON, OF MELROSE, MASSACHUSETTS.

METHOD OF AND APPARATUS FOR HEAT-TREATING METALS. I

Specification of Letters Patent.

Patented Sept. '7, 1920.

Application filed November 11, 1918. Serial No. 262,078.

T 0 all whom it may concern:-

Be it known that I. LAWRENCE E. JOHN- so), a citizen of the United States of America, and a resident of Melrose, in the county of Middlesex and State of Massachusett-s, have invented certain new and useful Improvements in Methods of and A the following is a specification.

This invention relates to methods of and paratus for Heat-Treating Metals, of which .apparatus for heat-treating metals and has for its object the provision of means where by selected portions of metal objects may be heat-treated without affecting the other portions of said object.

This is particularly desirable where it is desired to intensely heat a part of the metal object preparatory to tempering or annealing the same.

In machine tools, for instance, it is desirable to temper the operating parts thereof without in any manner changing the condition of the other parts of the device.

In gears, for instance, it may be desired to temper the teeth thereof while the remainder of the gear remains in its normal condition.

In drills, for instance, it may be desired to temper the cutting gedges thereof without changing the condition of the body thereof. here such metal objects are subjected to an intense heat in a furnace the condition of the entire object is affected and often the surface thereof is so over-heated as to damage it to such an extent as to make the object useless. I

By the present method all the objections which are found in the furnace method of heat-treating are entirely overcome and it is possible to localize the heat in the object.

Obviously this is of great advantage as it prevents undue injury to the object and furthermore makes a great saving in time and expense.

The invention consists in an, apparatus provided with interchangeable dies and punches the shape and size of which depends entirely upon the work to be operated upon, and transmitting from one to the other through the Work a current of electricity of sufficient intensity to heat the SB\ lected portion of the work to the degree de sired.

The invention also consists in the method whereby a current of electricity may be transmitted "through a selected portion of a metal object and heat the'same without affecting the remaining portions of said object.

The invention further consists of a method whereby a metal object may be heated by electricity, with the initial heat concentrated at any given point in said object and subsequently developed in other parts of the selected portion of the object being heated.

The invent-ion further consists in certain novel features and combinations of parts in an apparatus used to carry out said method which will be readily understood by reference to the description of the drawings and to the claims to be hereinafter given.

For the purpose of illustrating the invention. one preferred form thereof is illustrated in the drawings, this form having been found togive satisfactory and reliable results, although it is to be understood that the various instrumentalities of which the invention consists can be variously arranged and organized, and that the invention is not limited to the precise arrangement and organization of the instrumentalities as herein shown and described, except as required by the scope of the appended claims.

The drawing represents an elevation partly in section of an apparatus adapted to be used in carrying out the method.

In the drawings, 10 is a'frame having mounted in the base thereof, a vertical cylin drical support 11 on which is mounted an arm 12, said arm 12 being provided with a split bearing 13, the clamping members 14 of which are adapted to rigidly clamp said arm 12 to the support 11 in adjusted position.

It is obvious that by loosening the clamp members 14, the arm 12 may be moved lengthwise of the support 11 or about the ASSIGNOR, BY MESN E ASSIGN- axis thereof and then again locked in any desired position relatively to thesupport 11. The outer end of the arm 12 is provided with a block 15, pivoted thereto at 16, said pivot providing means whereby said block may be moved into Various angles relatively to said arm 12.

The block 15 has projecting therefrom an arbor 17 surrounded by a copper electrode 18. The outer end of the arbor 17 is provided with a cylindrical hole, to receive the shank 19 of the work supporting die 20. Above or in alinement with'the die 20 is positioned a vertically reciprocating shaft 21 having SWlX'GlQCl thereto a copper electrode 22 from which a heatingmember or punch 23 extends downwardly toward the die 20.

The shaft 21 is adapted to be reciprocated in a bearing 24 formed in the upper end of the frame 10. This reciprocatory movement is imparted to the shaft 21 by means of the lever 25 pivoted to the frame 10 at 26, said lever having a longitudinal slot 27 formed therein into which extends a pin 28 mounted in the reciprocating shaft 21. This pin 28 extends into a vertical slot 29 formed in the wall of the bearing 24 thereby preventing the shaft 21 from rotating about its axis.

The lever 25 is provided with a handle 30 by which said lever may be moved about its pivot 26 when it is desired to move the heating member 23 toward the work superimposed upon the die 20.

The lever 25 has secured thereto a plate 31 of non conducting material having mounted in its outer end a contact member In the handle 30 is positioned a sliding member 33 having a contact block 34 secured thereto but separated therefrom byv means of the insulating member 35.' This sliding member is adapted to be pressed outwardly by means of a helical spring 36 mounted in said lever 25 thereby normally retaining the contact block 34 separated from the contact member 32.

The outer end of the sliding member 33 is provided with a thumb pad 37 by which the operator may move the sliding member 33 inwardly so that the contact blocks 32 and 34 will be brought into contact with each other thus completing an electric circuit.

The contact block 34 is connected by a wire 38 with a dynamo, or other source of electric energy, 39, said dynamo being also connected by the wire 40 with a transformer 41 which may be of any well-known construction.

This transformer 41 is connected by means of a wire 42 with the contact member 32. It, is obvious, therefore,'that when the operator presses inwardly upon the thumb pad 37 and the contact members 32 and 34 have been brought into contact with each other, the electric circuit will be completed and a current will pass from the dynamo 39 into the transformer 41.

This transformer 41 is connected by a wire 43 with the electrode 22 and is likewise connected by means of a wire 44 with the electrode 18. Thetransformer is provided with may be of iron, steel or any other metal adapted for use as a conductor of electricity and these members may beof any size or shape depending upon the class of 'work to be done. For instance, if a reamer or some similar tool is to be heat-treated a cylindrical, die and a cylindrical heating member similar to those shown in the drawing will be used, while in case it is desired to heattreat the teeth of a gear the die andheating member shown in the drawings will be removed and other disk-like members having annular flanges will be substituted therefor. In other words, the method and apparatus is adapted to heat-treat all shapes and sizes of work made of metal. For this reason, in order to better operate upon work having odd shapes, the arbor 17 is mounted in the block 15 so that it may be adjusted about the pivot 16 by which it is secured to the arm 12 and having this same result in view, the arm 12 is provided with means whereby it may be adjusted vertically and about the axis of the supporting member 11.

When the heating member or punch 23 and the die 20 are of the same diameter and .made of the same material, if a piece of work is inserted between the die and punch and the electric current is passed through the work, the work will first be heated at'a point midway of its length and will begradually heated toward the ends thereof.

If it is desired to heat-treat one end of a piece of work, this may be accomplished by having the punch die 20 of another, these two metals being selected so as to obtain the result desired.

When the metals are heat-treated according to this method the selected .spots or parts of the metal-are subjected to the heat without in any manner afiecting the surrounding parts of the work.

By means of this method, the metals may be heated from the inside outwardly. Heretofore, when metals are to be treated preparatory to tempering or annealing them and the heating, is accomplished in a furnace as has been heretofore the practice, the entire metal is heated which is objectionable in many cases. Moreover, in heating metals by the furnace method, the heat is always transmitted to the metal from the outside 23 of one metal and the inwardly and the outer faces of the metal are frequently overheated and damaged to such an extent as to make them useless.

These objections are wholly overcome when the present method is used as the initial heating of the metal is at the interior of the piece of work being treated, the heat gradually working outwardly until the portion of the work to be treated has been brought to the required heat.

In consequence of this treatment the outer surface of the work is never damaged. In the operation of the invention the work is first placed upon the die 20, which is preferably made of iron, and the upper heating member or punch 28 is then brought down by means of the lever 25 until said punch is in contact with the upper face of the work to be treated. The operator then by pressure upon the thumb pad 37, makes'a complete electric circuit between the wires 38 and 4:2 by bringing the members 32 and 34; into contact.

The completion of the electric circuit causes a current of electricity to pass through the selected part of a piece of Work to be heat-treated.

The transformer 41 is always in the elec tric circuit and the hand 46 must be set to cause the resistance in the parts selected suflicient to produce the required heat in the work being treated.

When sufficient electric current has been passed through the work to accomplish the desired result the operator breaks the circuit by releasing pressure upon the thumb pad 3 T he punch 23 may be retained in contact with the work after the circuit has been broken thereby permitting the heat already generated in the work to more gradually act on the selected parts to be treated.

It is obvious that no electricity is used except during the operation upon the work thus making a great saving in expense over the electrically heated furnaces in use to some extent.

\Vhere electric furnaces are used considerable time is consumed in getting them into condition for use while in the present method the work can be operated upon at once by setting the transformer regulator for the required heat desired and then bringing down the lever 25 and completing the electric circuit in the manner hereinbefore described.

By means of this method and apparatus any portion of a metal'object may be heated preparatory to being tempered or annealed without heating other portions of said object. the electric circuit assing through the work passing in a straight path from the punch 23 to the die 20.

It is believed that the operation and many advantages of the invention will be readily understood from the foregoing description.

Having thus described my invention, 1 claim 1. The combination of a die member composed of metal of low conductivity a punch member movable toward said die member; supports for said members; electrodes surrounding said supports and composed of metals of high conductivity; and means for transmitting a current of electricity through said electrodes from one member to the other and through the work interposed between said members.

2. The combination of a die member composed of metal of low conductivity; a punch member movable toward said die member and composed of metal of low conductivity; supports for said members; electrodes surrounding said supports and composed of metals of high conductivity; means for transmitting a current of electricity through said electrodes from one member to the other and through the work interposed between said members; and means, whereby the initial heating in said work may be located at any selected point in the interior of said work.

3. The combination of an arbor; a die member of metal of low conductivity removably mounted therein; a plunger movable toward said die member; a punch member of metal of low conductivity removably mounted thereon; electrodes surrounding said arbor and plunger and composed of metal of high conductivity; and means for transmitting a current of electricity through said electrodes from one member to the other and through the work interposed between said member.

4. The combination of an arbor; a die member of metal of low conductivity removably mounted therein; a plunger movable toward said die member; a punch member of metal of low conductivity removably mounted thereon; electrodes surrounding said arbor and plunger and composed of metal of high conductivity; a transformer; flexible conductors between said electrodes and transformer; and means for transmitting a current of electricity through said electrodes from one member to the other and through the work interposed between said members. e

5. The combination of a die member of metal of low conductivity; a punch member; a plunger on which said punch is mounted; a lever for imparting endwise movement to said plunger; a die member of metal of low conductivity; a support therefor; electrodes on said plunger and die support and com posed of metal of high conductivity; an electric circuit; a transformer in said circuit; conductors between said electrodes and erated means carried by said lever for making and breaking said circuit.

The combination of a die member of metal of low conductivity; a cast iron support therefor; a copper electrode thereon;

a punch of metal of low conductivity; a

movable support therefor; a copper electrode thereon; a transformer; conductors from said-transformer to said electrodes; an electric circuit; and a manually operated circuit breaker.

8. The combination of a die member of metal of low conductivity; a support therefor; a punch of metal of low conductivity;

a movable support therefor; electrodes on said supports and composed of metal of high conductivity; a transformer; conductors between said electrodes and transformer;

means for transmitting an electric current to said electrodes; and means for adjusting said die support vertically andretaining it in adjusted position.

9. The combination of a die member of metal of low conductivity; a support therefor; a punch of metal of low conductivity; a movable support therefor; electrodes on said supports and composed of metal of high conductivity; a transformer; conductors between said electrodes and transformer; means for transmitting an electric current to said electrodes; a vertical cylin-,

drical member; and means whereby said die support may be moved about the axis of said vertical member and clamped in adjusted position.

10. The combination of a die member of metal of low conductivity; a support therefor; a punch of metal of low conductivity; a movable support therefor; electrodes on said supports and composed of metal of high conductivity; a transformer; conductors between said electrodes and trans former; means for transmitting an electric current to said transformer and electrodes;

a vertical cylindrical member; an arm mounted thereon and adapted to be moved about the axis thereof and clamped in adjusted position; and means for securing said die support to the outer end of said arm.

11. The combination of a die member; a

support therefor; a punch; a movable supmenace port'therefor; electrodes on said supports; a transformer; conductors between said electrodes and transformer; means for transmitting an electric current to said transformer and electrodes; a vertical cylindrical member; an arm mounted thereon and adapted to be moved about the axis thereof; and a pivotal connection between said sup port and the outer end of said arm.

12. The method of heat-treating metal a. ticles which consist in placing the work to be. treated upon a die member composed of metal of low conductivity, bringing a punch member intocontact with the opposite face of the work, and then transmitting a current of electricity through the work from one member to the other.

' 13. The method of heat-treating metals which consists in placing the work upon an iron die member, bringing a punch member into contact with the opposite face of the work, and then transmitting a current of electricity through the work from one member to the other.

14. The method of heat-treating metal articles which consists in placing upon a die member the work to be treated, bringing a punch member composed of metal of low conductivity into contact with the opposite face of the work, and then transmitting a current of electricity through a transformer and then through the work from one member to the other.

15. The method of heat-treating metal articles which consists in placing upon a die member the work to be treated, bringing into contact with the opposite face of the work a punch member of a selected metal adapted to coact with the die member to attain an initial heating in the work at a selected point, said die member and punch having different degrees of conductivity,

and then transmitting through the work an electric current from one member to the other.

16. The combination of a vertical member, a supporting arm adjustable endwise thereon; means for clamping said arm in adjusted position; an arbor carried by said supporting arm; a die on said arbor; a movable punch coacting with said die; elec trodes surrounding said punch and die; and means for transmitting an electric current to said electrodes.

17. The combination of a vertical member a supporting arm adjustable endwise thereon and about the axis thereof; means for clamping said arm in adjusted position; an arbor carried by said supporting arm; a die on said arbor; a movable punch coacting with said die; electrodes surrounding said punch and die; and means for transmitting an electric current to said electrodes.

18. The combination of a vertical member,

" a supporting arm adjustable endwise there- Si ed by me at 4 Post Oflice Square, Boson; means for clamping said arm. in adton, assachusetts, this 8th day of Novem- 10 justed position; an arbor pivoted to said her, 1918. supportin arm a die on said arbor a mov able pun h coacting with said die; elec- LAWRENCE JOHNSON trodes surrounding said punch and die; and Witnesses:

means for transmitting an electric current to EDWARD F. ALLEN,

said electrodes. WALTER E. LOMBARD.

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