US1182006A - Method of manufacturing bolts. - Google Patents

Description

, H. T. FRAUENHEIM. METHOD OF MANUFACTURING BOLTS.

APPLICATION FILED MAYH, 1913.

Patented May 9,1916.

WITNESSES INVENTOR HARRY 'I'. FRAUENHEIM, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO KERNEB MANUFACTURING COMPANY, OF PITTSBURGH, PENN$YLVANIA, A. CORPORATION OF PENNSYLVANIA.

METHOD OF MANUFACTURING BOLTS.

Application filed May 17, 1913.

To all whom it may concern Beit known that I, IIABRY T. FRAUEN- I-IEIM, a citizen of the United. States, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Method of Manufacturing Bolts, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming part of this specification, in which Figure 1 is a sectional perspective view, largely conventional, showing one form of heating furnace which I may use in carrying out my invention; Fig. 2 is a perspective view, also largely conventional, showing one form of upsetting and welding dies; Fig. 3 is an elevation, partly in section, and illustrating the manner in which the stay bolts are twisted; and Figs. 41 and 5 are elevations showing apparatus for threading the bolts. Figs. 3, 4 and 5 are also largely conventional. Fig. 6 is a plan view of a track bolt made in accordance with my invention.

My invention has relation to a novel method of making stay bolts and the like of the general character described and claimed in the patent of Ethan I. Dodds, No. 1,121,173, issued December 15, 1914, and also track bolts and the like of the general form described and claimed in the pending application of Ethan I. Dodds, Serial No. 7 59,916, filed April 9th, 1913. The stay bolts consist of solid threaded end heads, which are connected by two bar members, which are twisted upon each other through an angle of at least 180 degrees. The track bolts consist of a body portion composed of a plurality of separable bar members twisted upon each other to an angle less than 180 degrees, and upset and welded at one end to form a flanged head, and welded and threadedat the opposite end.

p In making my improved stay-bolts, I preferably proceed as follows :I take two bar members preferably of staybolt iron, and pile them together to form a cylindrical blank. In the drawing I have shown each of the blanks as made up of two semicylindrical members 2. These blanks are then inserted in a suitable furnace, and are locally heated to approximately a sweating heat, at which the end portions of the bar members will begin to unite. The furnace should be Specification of Letters Patent.

Patented May 9, 1916..

Serial No. 768,286.

of such character that only the end portions of the members which are to be upset to form the head of the bolt will be heated to an appreciable extent. In Fig. 1 I have shown, moreor less conventionally, a suitable furnace for this purpose. This furnace, which is a gasfired furnace, is indicated at 3. 4 designates the opening through which the gas is delivered to the heating chamber of the furnace, and 5 is the outlet opening leading to a stack, not shown. The heating chamber of the furnace is provided with a stepped wall 6, and the opposite wall is provided with a plurality of openings 8 through which the blanks to be heated are inserted. The distance between the face of the stepped wall and the opposite wall is just sufiicient to expose within the furnace the desired length-of the blanks to'be heated, while the rest of the length of the blank being either in the wall or outside the furnace wall does not become heated to an objectionable extent.

After heating, the piled blank is withdrawn from the furnace. and its heated end is simultaneously upset and welded by the action of suitable dies, Fig. 2 shows more or less conventionally dies which may be used for this purpose. In this figure, 9 designates a sectional die block between which the heated ends of the blanks are clamped, and which are formed with die cavities into which the said ends extend. By the action of a suitable plunger, such as shown at 11, the upsetting or welding to form the heads 12 is effected. The die cavities 10 should be larger than the diameter of the head desired, preferably by at least one-sixteenth of an inch, in order to compensate for the losses in scale when welding together a plurality of separate bar members, and also for losses by subsequent machining before threading. After forming one or both of the-heads 12 in the manner described, the blank is then twisted through an angle of at least 180 degrees. In accordance with my invention the twisting of the bar members is effected after one end of the blank has been heated and upset in the manner described, and before heating and upsetting the opposite end. This twisting may be effected by any suitable means. In Fig. 8 I have shown the headed end of'the blank as held in suitable clamp 13, while a twisting die 14 is applied to the opposite end portion thereof. After the twistingoperation,

the other end of the blank is then heated in I been continuously threaded from one end to the other and the intermediate portion of the bar then turned off toremovethe threads of such portion. This threading may be effected by first advancing one of the heads 12 while in a suitable lathe into a suitable threading die 15, as shown in Fig. 1. After this head has been threaded, the blank is reversed end for end, and the opposite end portion is then threaded in the same or a similar die, as indicated in Fig. 5. The usual telltale holes, not shown, may then be drilled longitudinally through one or both heads into each connectingbar member.

My invention provides for the rapid, economical and eflicient manufacture of stay bolts of this character. It provides a bolt having a highdegree of flexibility with respect to vibration strains due to relative movements-ofthe sheets in which the two ends of the bolt are inserted in use, while at the same time it has a high degree of resistance to compression and tension strains.

In service, the bolt is subjected to vibrations and gyratory movements due to the movements of the plates on the boiler which are connected by the bolts. Owing to the twisting of the barmembers through at least 180 degrees, the points of greatest bending stress during these movements will be shiftedthrough the bar members instead of being localized near one end of the bolt, as is the case with ordinary bolts. Consequently, the life of the bolts is greatly extended. The

7 twisting of the bar members through an angle of at least 180 degrees, also gives the bar the necessary stiffness in securing it in place.

I have found that if fouror more bar members are used in forming the bolt, the latter will not give the desired resistance to the strains to which it is subjected. It is also difficult to insert it in place, since after one head has been partly screwed into place and the screw threads on the other head be- 7 gin to. engage the other sheet or plate, the

torsion in applying will twist the bolt slightly and cause it to bind so that it cannot be completely inserted. With four or more connecting bars difficulty is also experienced in threading, on account of the liability of head. After the bolts are inserted in place,

the slightly projecting head portions must be peened over or headed slightly to retain them in place and make, tight joints. Where four or more bar members are employed, this action distorts and injures the bolt, since its diameter is limited to certain established standards and the cross-section of the bar members cannot therefore be increased.

By using two of the bars, however, their cross-section is suliicient to give the desired resistance to strains in making, as well as in applying and in use. This cross-section is also sufficiently large to properly contain the telltale holes without unduly weakening the bar members. These telltale holes are necessarily of a fixed diameter, determined by the Government standards, and these are fully met by the bolts formed by my invention, in which either two or three bar members are twisted in the manner described. Furthermore, by using two bar members, they will remain together in pile form during heating, whereas, it would be difficult to hold a greater number together while heating them and while inserting them into the upsetting and welding dies. It will be further noted that my improved method leaves undisturbed the original scaled or rolled surfaces of those portions of the bolts between the heads. This gives a much better surface for resisting the action of water than where a machined surface is exposed. The natural skin formed on the bar members during their manufacture is not cut away or disturbed, and consequently, the stay bolt is much stronger.

By the term stay bolt as used herein, and in the claims, I do not intend to restrict the use of my invention to bolts for boilers, as it is obviously adapted to the manufacture of various bolts of this general type.

The method of manufacturing headed bolts, such as shown at 15 in Fig. 6, is similar to that above described, except that the bar members are twisted upon each other less than 180 degrees, and only one end of the blank is upset, viz., the end which forms the flanged head 16. The other ends of the members are simply welded and threaded. The twisting of this form of bolts is less than 180 degrees because it is desired that the bolts shall not be rigid under tension stresses but shall be capable of some elongation un der excess strains.

I claim 1. The herein described improvement in the manufacture of bolts, having a head and a twisted portion formed of separate members, which consists in forming a head on one end of the bolt blank, then twisting the same, and then welding together said separate members at the opposite end portion of the blank; substantially as described.

2. The herein described improvement in the manufacture of bolts, having a head and a twisted portion formed of separate mem- In testimony whereof, I have hereunto set bers, which consists in forming a head on my hand.

one end of the bolt blank then twisting the same, and then Welding tbgether said sepa- HARRY FRAUENHEIM' rate members at the opposite end portion of Witnesses:

GEO. B. BLEMING,

the blank and upsettin them to form a head JEssE B. HELLER.

at that end; substantia 1y as described.

monies of thie patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C.

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