US938339A - Tool. - Google Patents

Description

G. F. RIESENWEBER.

V TOOL. APPLICATION IILIBD HAY26, 1904.

Patented 001;.26, 1909.-

2 SHEETS-SHEET 1.

Inventor:

Witnesses:

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. a, 1904. I 938 339, Patented 0011.26, 1909. 9 z SHEETS-SHEET 2.

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CARL F. RIESENWEIBER, OF ST. LOUIS, MISSOURI.

TOOL.

Specification of Letters Patent.

Patented Oct. 26, 1909.

Application filed May 26, 1904. Serial No. 209,875.

To all whom it may concern:

Be it known that I, CARL F. RIESENWEBER, a citizen of the United States, and a resident of the city of St. Louis and State of Missouri, have invented a new and useful Improvement in Tools, of which the following is a specification.

My invention relates to taps for threading holes in separated plates, as, for example, stay-bolt holes in locomotive boilers.

It has for its principal objects to facilitate the reaming and threading of holes; to accurately thread alined holes in separated plates so that the two threads shall lie in the same helicoid surface; to shorten staybolt taps; to reduce the number of taps required to thread all the stay-bolt holes in a locomotive boiler; and other objects hereinafter more fully appearing.

My invention consists in the parts and in the arrangements and combinations of parts hereinafter described and claimed.

Inthe accompanying drawings forming a part of this specification and wherein like symbols refer to like parts wherever they occur, Figure 1 is a view of a compound stay-bolt tap comprising two taps on a threaded spindle, one of said taps being shown in section; Fig. 2 is a View of a compound stay-bolt tap, one of the taps being integral with the threaded spindle; Fig. 3 is a section in the plane of the line 3 3 of Fig. 2; Figs. 4 and 5 are fragmentary sectional views in the planes of the lines 4: 4 and 5 5 of Fig. 3 respectively; Figs. 6 and 7 are fragmentary sectional views of a modification corresponding to Figs. 4. and 5 respectively; Fig. 8 is a vertical sectional view'through the fire-box portion of a locomotive boiler; Fig. 9 is a view of a small part of a fire-box sheet showing the manner in which these sheets crack in service; Fig. 10 is a view'of a reamer constructed according to my invention.

In many places it is desirable to connect two separated plates or sheets by bolts having screw threaded engagement with both. The construction of locomotive boilers is a familiar example of this, the plates of the water legs and the crown sheet and outer sheet over the fire-box being connected by stay-bolts. To properly effect this connection it is necessary for the-holes to be perfectly alined and parallel with the direction of the stay-bolt and for the threads of alined holes to lie in the same helicoid surfaces. It is the common practice to prepare the staybolt holes by means of a tool comprising a reamer, a tap, and a shank. As the reamer must be long enough to aline the tool, and the tap must be long enough to start the thread in the inner or second plate before being disengaged from the thread in the outer or first plate, and the shank must be long enough to make it possible to finish the inner or second thread, this tool is necessarily about three times as long as the distance between the plates. These tools must be hardened, which, on account of their length, is very difficult, if not impossible, to do withouta change in the lead of the thread and without warping. These changes in shape are so great as to render a large portion of the tools made useless and a considerable number of imperfect ones are put into use. The said change in lead is very objection able for if a stay-bolt is forced into place and one of the threads does not mesh with the thread in the corresponding plate, a boiler explosion is likely to be the result. Such a tool long enough to thread the holes for the stay-bolts in one part of a boiler cannot be used to thread the holes for the staybolts in another part, because it interferes with some portion of the boiler. Consequently a large number must be provided. This tool is expensive, is a source of loss and vexation to the boiler maker, and is a source of danger to the user of the boilers. My invention is designed to overcome these objections.

My improved tapping tool comprises a threaded spindle having a tap or taps mounted thereon. The spindle 1 is provided with a thread of any desired shape and pitch which may continue from end to end of the spindle or may be interrupted at the middle portion of the spindle. The latter case is illustrated. The threads on the opposite ends lie in the same helicoid surfaces, each being a continuation of the other. spindle is preferably made of annealed carbon tool steel and is not hardened for it is not used as a cutter at all. Distortion of the threads in the hardening process is thus avoided, and the finished spindle is true. The spindle is provided with a polygonal enlargement 2 by means of which it may be held or turned in the taps in case of sticking. A spindle screw threaded throughout its This i llC entire length might be provided with kerfs in the ends for a screw driver or with check nuts.

Upon the spindle hollow taps 3, 4 are screwed. These taps are made by placing them on the spindle and threading them in place. same pitch and correspond exactly with the threads on the spindle. Consequently the threads on one tap have the same pitch and correspond to the threads on the other tap. At their outer ends the taps 3, 4 are provided with polygonalheads 5, 6 respectively, to provide for the turning of the taps by means of a wrench. Notches 7, S are cut in the ends of the taps, said notches extending to the threaded hole through the taps. The walls of the notches act as scrapers to clean out the threads of the spindle. Similar notches 9, 10 are cut in the ends of the spindle and their walls act as scrapers to clean the threads in the taps. The taps are preferably made of alloy tool steel because of the great superiority in its cutting qualities over carbon tool steel. They are hardened with greatly reduced distortion of the threads because they are so short, each tap being required to be only long enough to thread a hole in a single plate.

In use one of the tapes is removed from the spindle, and the latter with one tap in place is passed through the two holes; after which the first tap is replaced on the spindle. The taps are then both in position to operate on their respective plates 11, 12 and may be simultaneously operated, one man working on the interior and another working on the exterior of the boiler. Each tap holds the other to its work and the spindle serves as a positive feed for them insuring true threads and alinement. The holes having been threaded the taps are removed and another pair of holes may be threaded in like manner. One spindle can be used upon a large number of pairs of holes as it is necessary for it to extend beyond the inner plate only far enough to receive the tap, the other end of the spindle projecting outside the boiler. For this reason also my improved tap can be used to thread holes upon which the old stay-bolt tap could not be used at all. Spindles are made of various convenient lengths and of a. standard diameter and any tap will fit any spindle of a set.

Ordinarily, the inner or advance ends of the taps form reamers 13, 14L, which ream out the holes in advance of the threading cutters. But when much metal is to be removed, it is desirable to use a reamer. A suitable tool is illustrated in Fig. 10. It comprises a spindle 15 like the spindle in the tap. Upon it are placed reamers 16, 17 screw threads fitting the threads on the spindle. tap, the spindle serving to insure alinement The threads on the taps have the provided with This reaming tool is used like the 7 of the holes and as a positive feeding means for the reamers.

It is sometimes desirable to make one of the taps rigid upon or integral with the spindle. A tool of this type is shown in Fig. 2. A spindle 18 is provided with an integral tap 19 of any desired diameter at one end. The spindle 18 is provided any desired shape and pitch and the tap 19 ms threads of the same pitch as and corresponding to the threads on the spindle. A hollow movable tap 20 is mounted on the spindle similarly to the mounting of the taps 3 a on the spindle 1. The spindle 18 and tap 19 integral therewith are made of alloy tool steel. The tap is hardened but the hardening extends only to the spindle, leaving the latter unhardened and avoiding the detrimental efiects upon it of the hardening process. The tap 22 is made of alloy tool steel and hardened. The end of the spindle 18 is provided with a polygonal portion 21 by means of which it may be turned. The tap 20 is provided with a polygonal portion 22 by means of which it may be turned. This form of tool is especially useful in patching jobs when the work is done upon the boiler in place on its frame and it is diflicult or impossible to work on one side.

It is common for cracks 23 extending radially from the stay-bolts to appear in the inner fire-box sheet 24, in that portion of the sheet in contact with the hottest part of the fire, as illustrated in Fig. 9. It is proposed to mend such places by drilling or chipping a hole concentric with the staybolt and extending beyond the end of the crack, as indicated by the dotted circle 25. A special stay-bolt 26 is provided having a threaded portion to fit the hole in the outer plate and an enlarged and threaded portion 27 to fit the large hole in the inner plate. My improved tool is adapted for threading these holes as a tap of a proper size to thread the smaller hole can be put on one end of the spindle and a tap of a proper size to thread the larger hole can be put on the opposite end of the spindle. If the patch staybolt is to be inserted in a part so'located that working from the exterior is inconvenient, as when the frame 28 or some other part is in the way the modification shown in Fig. 2 should be used.

with threads of iii The taps may be provided with ordinary rib 32 is similar to the rib 30. The invention is shown in these figures applied to cutting teeth of a bottoming tap, the shape of ordinary cutting teeth being indicated by the dotted lines. Adjacent faces of each pair of teeth, as 38 and 34, are provided with angular cutting edges, the cutting edges upon the opposite faces being shortened, as if the old form of tooth were truncated at an angle to the axis of the tap. The teeth upon the succeeding rib of the tap are similarly shaped but are so located that the tooth 35 immediately succeeding the tooth 33 and the tooth 36 immediately succeeding the tooth 34c are truncated upon the sides opposite to the truncation of the teeth 33 and 34-. Thus each tooth is required to cut away only a portion of the metal removed by the old form of tooth. At ,last, teeth of triangular shape follow and cut away the small amount of metal remaining in the bottom of the thread. By this expedient the force necessary to turn the tap is much reduced. All forms of tap cutting teeth, whether taper taps, plug taps, or bottoming taps may be improved in this way. The alternate portions of succeeding teeth of the old shape are cut away.

A modification is illustrated in Figs. 6 and 7. In the ordinary cutting teeth both faces of a tooth are provided with cutting edges. In this modification the teeth are cut away on one side so as to provide cutting edges on one side only. Alternate faces of succeeding teeth are provided with cutting edges, one tooth cutting one side of the thread and the succeeding tooth cutting the opposite thread.

Obviously this device is capable of modification within the scope of my invention and therefore I do not wish to be limited to the specific construction shown and described. F or example, in the modification shown in Fig. 2, the spindle 18 may be made of carbon tool steel and the tap 19 may be made of a separate piece of alloy tool steel and rigidly secured to the spindle.

That I claim as my invention and desire to secure by Letters Patent is:

1. A tool comprising a threaded spindle, a tap rigid with said spindle, and a hollow internally threaded tap working on said spindle and having a diameter greater than the diameter of said first mentioned tap, said taps being arranged to work in the same direction and cut threads having a pitch corresponding to the pitch of the threads on said spindle.

2. A tool comprising a threadedspindle, a tap rigidly attached to said spindle, and a hollow internally threaded tap working on said spindle, said taps being arranged to work in the same direction.

In testimony whereof I have hereunto signed my name in the presence of two subscribing witnesses this twentieth day of May, 1904, at St. Louis, Mo.

CARL F. RIESENWEBER.

Witnesses ARTHUR HAERTING, FELIX E. GoERLIoH.

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