US1393726A - Puppet-valve - Google Patents

Description

- c. A. PFANSTIEHL.

PUPPET V APPLICATION FILED. 8, 1917- 1,393,726. Patented Oct. 11, 1921.

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CARL A. PFANSTIEHL, 0F HIGHLAND PARK, ILLINOIS, ASSIGNOR TO PFANSTIEHL COMPANY, INC., 01 NORTH CHICAGO, ILLINOIS, A CORPORATION OF NEW YORK.

PUPPET-VALVE.

Application filed February To all whom it may concern:

Be it known that I, CARL A. PFANSTIEHL, a citizen of the United States, residing at Highland Park, in the county of Lake and State of Illinois, have invented a certain new and useful Improvement in Puppet- Valves, of Which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawin 's, forming a part of this specification.

y invention relates to puppet valves for internal combustion engines.

The principal object of my invention is to provide a valve which shall be extremely strong and at the same time light.

I accomplish my object by constructing my valve in accordance with the process set forth in my co-pending application Serial No. 276 044, filed February 10, 1919, for

improvement in articles of manufacture and method of making same.

In accordance with this co-pending application a valve is constructed having a pressed metal head of high speed steel fused to a stem of a different character of steel more suitable for stems than is the high speed steel and also less-expensive.

In accordance with my present invention I fuse a hollow stem of so-called Nychrome steel to the central portion of a cupped disk of high speed steel and then fuse onto the other end of the stem a solid button of high carbon steel adapted to receive the thrust from the end of the push rod.

My invention is illustrated in the accompanying drawings in which,

Figure 1 represents a blank of high speed steel from which the valve head is con-.

structed .to form Fig. 3 illustrates the valve head and hollow stem in association with the supporting electrodes of a fusing machine before the current is applied;

Fig. 4 represents the stem and valve in the fusing machine after the fusingoperaion;

Fig. 5 is a section through the rear receiving button;

Fig. 6 illustrates the valve'stem and button in the-fusing machine after the fusing operation; and

Fig. 7 represents the completed valve.

Specification of Letters Patent.

Patented Oct. 11, 1921.

a, 1917. Serial No. 147,a95.

Fig. 1, the preferred thickness being about gof an inch in the raw stock. This disk may be punched, or otherwise cut, from sheets of annealed metal.

High speed or so-called tungsten steel which contains vanadium is worked only with great difiiculty, but I have found that by heating the disk to a temperature of between 1450 and 1550 degrees Fahrenheit the disk may be formed into the shape shown in F igs. 2 by a single operation. The heat must not be permitted to rise above 1550 degrees Fahrenheit because at greater tem perature the metal when cooled by contact with the dies by means of which it is stamped becomes somewhat hardened. In fact so much so that it will not withstand the-irregular heat of the fusing operation without cracking. If, however the temperature to which the disk is raised for the stamping operation is maintained below 1550 degrees Fahrenheit the original annealed condition of the metal is not mate-' rially changed and the metal is not cracked by the heat of the fusing operation when the operation is carried on in the manner hereinafter described.

The disks 10, as illustrated in Fig. 2, are sandpapered, or otherwise brightened on both the upper and under sides of the central flattened portion and near the periphery on the concave side.

The stems which I have found most satisfactory for this type of valve are composed of what is termed Nychrome steel. This steel analyzes substantially as follows in addition to its iron component: nickel 1.50%; chromium 35%; carbon 35%; manganese 50%; sulfur, less than 04%; phosphorous, less than 04%. Steel having this composition does not readily oxidize at the temperatures at which it is operated as valve stems, nor is it seriously attacked by the combustion gases of an internal combustion engine. It withstands the wear incident to the slipping up and down in the supporting sleeves better than either high speed steel or carbon steel.

In order to produce a valve in its finished form with a stem of an inch in diameter I prefer to start out with a hollow stem about of an inch outside diameter and inch.

from the stem provided with a inch hole. In the completed valve, therefore, the thickness of the wall of the valve stem is about of an Nychrome steel, such as I prefer to use for these valve stems, cannot be welded by the ordinary processes heretofore commonly used.) This metal when heated to a temperature correct for the ordinary welding op,- eration becomes so crumbly that if hit with a hammer it breaks up into small crystalline particles.

A tube 11 of metal of the above described character is clamped within the upper copper electrode 12 of an electric fusing machine. The disk 10 is supported upon the lower copper electrode 13 of the fusin machine. The electrodes 12 and 13 of thls machine are connected with a suitable source of electricity suflicient for supplying a quantity of current about four times as great "as that used in electric welding. The electrode 13 is so shaped that it initially contacts with the tungsten steel disk 10 only at or near the periphery of the disk, the purpose of this being to cause aninitial flow of current radially through the disk to pre-heat the latter at points away from the fusing position thereof in order to sufiiciently soften the disk to prevent cracking due to the high heat of fusion and to prevent internal strains due to the cooling after the fusion operation.

After assembling the disk 10 and stem 11 n the fusing machine a small inclosure 14 is brought into position about the parts to be united and hydrogen, or some other inert gas, is inclosure through the intake pipe 15. A downward pressure of several hundred pounds is nowapplied to the stem, but this pressure is insufficient to deflect the disk 10 so as to bring its central portion in contact with the; lower electrode 13. While this pressure s still exerted the primary circuit of a transformer, which is preferably used for supplying the fusing current, is closed and the current from the secondary is directed through the electrodes, the disk 10, and the stem 11. Although the circuit is completed for less than one second the re sult of the current flow is to heat the disk 10 throughout substantially its whole surface to a dull red thus softening it sufliciently that the disk is deflected under the pressure so that the lower central surface of the disk comes into intimate contact with the central portion of the lower elecadmitted to the space within thev trode. Immediately following this initial deflection of the disk the stem 11 begins to soften and melt away at the point of contact with the upper surface of the disk. The pressure is still maintained and the stem is fed toward the disk as it melts away at its point of contact with the disk. After a movement of about one-half the distance through which the stem is fed against the disk the surface of the disk begins to melt andthereafter throughout the remainder of the movement of the stem toward the disk the metal of the disk and that of the stem where they are gradually melted at the point of contact boils and bubbles and thoroughly mixes. Some of this mixed metal is forced outwardly and forms the collar 16 shown in Fig. 4, while some of it is forced inwardly and" ascends within the hollow portion of the tubular stem and forms the reinforcement 17 also shown in Fig. 4. This reinforcing portion 17 may be caused to ascend as much as three-fourths of an inch within the hollow portion of the tube if desired, but experiments show that a onefourth inch rise of this reinforcing member carries the reinforcement beyond the point at which solid "stems ordinarily give way under use and, therefore, that any further extension of this reinforcing member is unnecessary. Analysis of the member 17 shows that the end most remote from the valve head is composed wholly of metal like the stem while portions nearer the valve head are composed of a mixture of the stem and head metals.

Although. the melting temperature for tungsten steel is several hundred degrees higher than that at which the stem metal melts, the herein described method of supporting the head and. stem and of feeding thestem toward the head brings about the actual fluid condition. of both head and stem at and near their points of contact, but at the same time maintains the other portions of the head and stem so cool that the character of themetal not changed at these other portions by the fusin operation. The surface of the head imme iatelyopposite the point of fusion is kept so cool by the copper electrode 13 that the mixture of the stem and head metals does not penetrate clear through to the under surfaces of the head 10. The collar of metal exuded from the stem and disk metals cools in contact with the upper copper electrode 12 and thus forms a retainer for the molten interior metal preventing the latter from escaping during the final period-of the fusion operation. In Fig. 4 the area of the blending of the two metals is illustrated by the over lapping of the cross section lines of the stem and disk.

The metal most satisfactory for hollow stems is not satisfactory for receiving the wear from the push rods and I have, therefore, found it advisable to fuse a button onto the end of the stem for receiving the wear. The button 18, shown in Fig. 5, is of the preferred form. This button may be made in a screw machine and is preferably made of high carbon steel. These buttons are preferably hardened by heating to red heat and then immersing in water. After being hardened they are placed in the same type of fusing machine as hereinbefore described and are fused by the same sortof operation as described in connection with the attachment of the head to the stem, excepting that the current required for fusing on the buttons is only about one-third that required for fusing together the heads and stems. The hardened butttons are supported in an electrode 19, as illustrated in Fig. 6', this electrode being of water cooled copper and making ver intimate connection with the button 18. n this way the temperature of the button is maintained quite low and the, temper is not drawn during the fusing operation. Before fusing the button onto the end of the stem the stem and head are brought each to its proper temper. The steel valve head at and very close to the margin of the fusion comes out of the fusion operation extremely hard and brittle. In order to prevent cracking of the disk around the fused portion the united members are annealed by packing in charcoal, or some other non-oxidizing packing, which excludes the air and by being held at a temperature between 1525 and 1550 degrees Fahrenheit for a period of one hour and then being gradually cooled down to about 200 degrees Fahrenheit throughout a period of two or three hours. When thus annealed all internal strains as were created during the fusing operation are permanently relieved.

In order that the valves may be rotated for grinding in and for re-grinding during service a small slot 20, illustrated in Fig. 7, is milled into the base of the concave part of the head. The valves are then turned to within a few thousandths of the final size at which they are to be used in an ordinary lathe or a special machine. The machined valves, complete except for the attachment of the buttons 18, are then heated, preferably in an electric furnace, to a tem erature of between 2000 and 2150 degrees ahrenheit.

It is desirable that the periphery of the valve head be hardened to a greater extent than is the central portion of the head. In order to accomplish this hardening of the periphery it must be cooled more rapidly than the central portion of the disk and, in fact, more rapidly than the tubular stem because it is desirable that the stem itself be kept quite soft and tough. In order to satisfactorily cool the perlphery of the disk I rotate the valve rapidly along the axis of the stem and at the same time apply a blast of cool air to the periphery of the head. I have found it desirable to protect the stem and central portion of the head from too rapid radiation and this may be done by any suitable inclosure.

After the head and stem have been hardened, as above described, the already tempered button 18 is fused to the stem in the mannnerhereinbefore described, care being taken to press the stem and button toward one another the right amount to secure a proper final length for the valve stem. The completed valve is lastly placed in a grinding machine and the head, stem, and button are ground to final size and finish.

Valves constructed in the manner herein described are particularly suitable for high speed engines since they have a strength substantially equivalent to valves having solid stems and uncupped heads. The amount of work required to oscillate the valves of high speed motors is no small proportion of the internal losses of the motors and by lightenening the valves without material loss of strength a substantial proportion of the heretofore lost power may be recovered.

Having thus described my invention what I claim as new and desire to secure by Letters Patent of the United States is:

1. A valve for internal combustion engines comprising a hollow steel stem, a head fused thereto, the mixed metal of the head and stem extending into the hollow portion of the stem and reinforcing the latter at and near its union with the head.

2. A valve for internal combustion engines comprising a hollow steel stem, a head fused thereto, and means for reinforcing sald stem at a point adjacent the union of the head and stem, comprising a block of metal formed integral with said head and extending into said stem.

In witness whereof, I hereunto subscribe ngyi zname this 31st. day of January, A. D. 1

CARL A. PFANSTIEHL.

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