US2309181A - Apparatus for forming closed tubes - Google Patents

Description

#11.26, .1943. @E FRANCK- 2,309,181-

APPARATUS FOR FORHING CLOSERTUBES Filed Nov. 12, 1940 Patented Jan. 26, i943 UNITED STATES IPATENT OFFICE APPARATUS FOR FORMING CLOSED TUBES George E. Franck, Riverside, Ill., assigner to The Imperial Brass Manufacturing Company, Chicago, Ill., a corporation oi' Illinois Claims.

made of metal' and formed from a single length of stock into tubes substantially closed at both ends andv suitablel forming apparatussuch as dies and appurtenances thereto for forming such containers.

Among the objects of my invention is to provide a new and improved apparatus for forming a substantially cylindrical container having substantially closed ends by operation upon a length of metallic cylindrical tubing stock.

A further object is to provide an apparatus consisting of dies and a centering means cooperable with the dies which are adapted to receive a piece of tubular stoel: centered properly within the dies and then compress the stock at one or at both ends simultaneously into the closed form of container desired and then open so that the container thus formed might be removed without it being necessary to break apart any parts of the separate coacting die platens.

It is further among the objects to provide platens and centering mechanism therewith which is adapted ilo/ correct 'en stock of a predetermined' sizeffwhie' slightly over or under size or "whic ma addition have irregularities on the surface.'

With these and other objects in view, my invention consists in the construction, arrangement and combination of the various steps of my method together with parts of my device whereby the objects contemplated are attained, as hereinai-ter more fully set forth, pointed out in my claims and illustrated in the accompanying drawing, in which:

Figure 1 is an elevational view in section showing upper and lower die platens and a length ci stock in place prior to the forming operation.

Figure 2 is a vertical sectional view similar to Figure l, showing the die platens in compressed position. v

Figure 3 is a cross-sectional view taken on the line 3--1 o! Figure 1.

l Figure 4 shows a method of heat treating the end oi' the tubular stock which is to be formed.

It has previously been the custom to use tubular stock for devices such as filters, dehydrators, strainers, scale traps, etc., which are citen used in liquid and gas lines where the liquid or gas is under considerable pressure or which may be of such-a nature as to enable it to leak out wherever even a'very slight leak might occur. YIt has likewise been the practice when making either by provi/ding threaded caps or when especially high pressures are encountered by attachf y lng theretovanges which are bolted together.

Such constructions are relativeLv expensive and entail a large number of manufacturing operations. Moreover, even when so designed, the

capped and threaded stock is unsuitable for very high pressures.

Metallic bodies having curved closed ends have frequently been found in the past to have great strength in proportion `to the gauge of the metal formed into such rounded shapes. However, in

providing a method for forming tubes ot relatively small diameter into such shapes having,v

rounded ends a dlfllcult problem is presented since all of the work must be perfumed upon the stock from the outside and no backing o r supporting structure can be effectively positioned within the Itube while the forming operation takes place.

This method and the apparatus, therefore, is directed to the provision of a means whereby tube v4'stock of relatively small diameter'may be 'outl and formed into containers comprising a single piece having rounded ends and which by reason of such construction have relatively great ystrength in proportion tothe gauge of the metal forming the tubular stock.

One embodiment of my invention directed to the provision of such an apparatus for prac. ticing my method is shown on the drawing;

where an upper platen I0 is shown opposed to a lower platen |2'wherein each are provided with suitable recesses for positioning and compressing a length of tubular stock I 4, as shown in Figure l, into a desired form I6, shown in Figure 2.

The upper platen l0 has'a recess comprising an annular curved portion'. I8 and a. cylindrical portion 20. The cylindrical portion has a diameter substantially equal to the outer diameter of the tube stock 'il so that the stock may slide easily into the recess. At the center of .the recess is a plug 22 having a conical end 24 extending into the recess and centered with respect thereto.

Itfwill be noted that the conical surface 24 at its point of Contact with the curved portion be provided with conical ends of various sizes.

l such devices to close the ends oi the tubular stock.

The lower platen I2 has a cylindrical hole 2l extending inwardly from a bottom edge 30 and a cylindrical aperture 32 on the upper side smaller than the ho1e'28 and communicating therewith. Within the hole 28 is an insert 34 forming a part of the lower platen. with its lower surface flush with the surface 30 of the platen and an upper edge abutting a shoulder 35. The insert has a recess comprising a cylindrical portion 88 having a Idiameter substantially equal to the outer diameter of the tube stock I4 and an annular inwardly curved recess portion 40 similar to the recess portion I8 of the upper platen..

Likewisethere is provided a plug 42 having an upper conical portion 44 extending centerably within the recess with the conical surface 48 at its point of contact with the curved portion 40 at substantially a right angle. The recess 48 is supplied for receiving the plug 42.v

lIn the aperture 82 of the platen l2 a sleeve 58 is inserted until it abuts 4an upper annular rim 54 of the insert 34. The sleeve is designed to fit snugly within the aperture buthas an inner diameter 56 substantially greater than the outside diameter of the tube stock I4. Opposed centering devices comprising spring members 58 are secured to the sleeve by means of screws, TheseA spring members are normally arcuate in shape as shown in Figure 3, and of resilient material such as spring steel. These are secured to the sleeve in horizontal position.

At each end of each of the spring members there is provided a hole or slot within which is positioned a pin 62. The pin extends through a hole 64 in the sleeve within which it has a free sliding nt and has a cap 66 securing it to the end of the spring member.

In the form of my invention shown, four pins are provided positioned in pairs and opposed to each other. The pins are permitted to move longitudinally with respect to their axes and are normallyspring pressed into the position shown in Figure 3 by the spring members 58.-

In Figure 4 there is shown a body18 of relatively cool liquid su'ch as water held in a container 12 and having a depth slightly less than the length of the tubular stock I4 permitting an end 14 to extend above the surface of the water. The length of the end 14 is substantially equal to the portion of the tube which is to be formed into a rounded closed end 16 as seen in Figure 2. In theparticular embodiment shown in Figure 4. there is provided a torch 18 designed to impel a heat stream 80 against the exposed portion of the tubular stock. It is contemplated, however,

and within the scope of my invention to provide a shallow bath of liquid such as lead lheated to the temperature necessary for annealing the tubular stock in order that the stock might be dipped in it. to the depth desired for forming A the closed end 16.

.edges-properly squared. Next, using one` of the 'forms of my method the stock is placed in a bath of relatively cool liquid to a depth such that the end protruding above the surface of the liquid is no longer than the length of the tubing stock desired to be heated and annealed.

The protruding end lcan then be readily heated by a torch as shown in Figure 4 or by some suitable similar means to a temperature preferably Aends of the tube `are to be closed, the stock is inverted in the liquid bath and the opposite end heated and doused.

After this has been done the stock is placed in the cylindrical portion 38 of the recess in the lower platen as shown in Figure 1 by slipping it downwardly through the sleeve 58. When in this position the lower cylindrical portion 38 holds the bottom endl and the pins 62 bearing against the side walls of the stock centered properly `with respect to the recess and the conical end 44 of the-plug 42. Next, the upper platen is lowered by suitable power machinery to the position shown in Figure 1, wherein the cylindrical portion 20 of the recess surrounds the upper annealed end of the tubular stock.

Then the platens I0 andl I2 are forced together by power means and while being so forced together, the tubular stock is forced into the form I6, shown in Figure 2, while remaining in a carefully adjusted center position by the centering pins. During the compressing stroke the ends of the stock which have been annealed are formed over into the curved ends 16 lying flat against the annular curved portions I8 and 40, respectively, of the recesses. The end edges of the stock are driven inwardly into the recesses until they make edgewise contact with the conical surfaces 24 and 46 of the respective plugs 22 and 42.

When this operation has been completed, the

' platens can be readily separated one from anready for the next container forming operation.

In the meantime, the container i6 thus shaped may be further machined by reaming the ends formed bythe plugs to size in preparation Afor the insertion of a standard fitting.

There has thus been provided a .method and' apparatus for making` a single piece'of tubular Istock into a high-duty closed. container vwhich` when equipped with the necessary fittings is suitable for use in high-pressure gas and. liquid lines withoutdanger-ofleaks and with a relatively minimum necessity for adjustment and repair. Some changes may be made in the construction and arrangement of th'e parts of my device Without departing from the real spirit and purpose of my invention, and itis my intention to cover by my claims any modified forms of structure,v or use of" mechanical equivalents, which may be reasonably included within their scope. v

I claim as my invention:

l. A device for forming a cylindrical length of tubing stock into a chamber having rounded, relatively closed ends comprising a platen having an aperture therein including a cylindrical portion for receiving said stock, an inwardly curved annular wall forming av bottom for said aperture and a centering element extending intothe recess at the center of said bottom, a second platen having an annular curved recess therein complementary to said first recess having a-limlited reciprocal movement relative to the first' ing devices in the sleeve, leach comprising a v spring pressed, laterallyreciprocable element secured to the sleeve extending through the sleeve wall 'to a point of contact with the wall of said stock and releasably held in said positions.

2. A device for forming a cylindrical length of tubing stock into a chamber having rounded, relatively closed ends comprising a platen having an aperture therein including a cylindrical portion greater in diameter than said stock, a

shoulderbeneath said cylindrical portion and an inwardly curved annular wall forming a bottom for said aperture, a plug extending into the recess at the center of said bottom, a second platen having an annular curved recess therein complementary to said ilrst recess having a limited reciprocal movement relative to the first platen to and from a' compressed position, a central plug in said second recess, a sleeve fitting within the aperture oi' the ilrst platen positioned against said shoulder and extending outwardly beyond the surface to a position spaced from the compressed position of said other platen, and a plurality of opposed centering devices'in th'e sleeve,

each comprising a spring pressed laterally recipmcable element secured to the sleeve extending through the sleeve wall to a point ofcontact with the vwall of said stock and releasably heldin said positions for centering the tube stock relative to theplugs.

3. A device for forming a cylindrical length of tubing stock into a chamber having rounded, re1- atlvely closed ends comprising a platen having an aperture th'erein including a cylindrical portion greater-in diameter than said stock, a shoulder beneath said cylindrical portion and an inwardly curved annular wall forming the bottom -for said aperture, a second platen having an annular curved recess ytherein complementary -to said first recess having a limited reciprocal movement relative to the first platen to and from a compressed position, a sleeve ilttlng within the aperture of the nrst platen positioned against said shoulder and extending outwardly beyond the surface to a position spaced from the compressed position of said other platen, and opposed t centering devices in the sleeve, each comprising an arcuate spring element surrounding a portion of th'e circumference of the sleeve in transverse position, a screw securing the center of said element to the sleeve and reciprocably mounted pins secured sleeve wall to points of contact with the wail of said stock and releasably held in said positions by said spring element.

ture therein greater in diameter than said stock and a base therefor, a cylindrical hollow inner member within the aperture, said inner member having a recessincluding a cylindrical side wall portion having a depth substantially/equal to the length of said stock adapted to be formed into one of said closed ends and equalin diamel .ter to the diameter of said stock, a shoulder at i ing one at each end of each said element extending through the 4. A device for forming a cynnd'ricn lengthy of tubing stock into a chamber having rounded, relatively closed ends comprising a platen having an outer member including a cylindrical aperthe top of said recess beneath said aperture and an inwardly curved annular wall forming the bottom of said recess and a plug extending into the recess at the center of said bottom, a second platen having an annular curved recess therein complementary to said first recess and having a limited reciprocal movement relative to the iirst platen to and from a compressed position, a central. plug at the bottom of said second recess, and a sleeve iittlng within the aperture of the rst platen positioned against said shoulder and extending outwardly beyond the surface to a position spaced from the compressed position of said other platen, and opposed transverse centering devices in the sleeve, eachv comprising an arcuate spring element surrounding a portion of the circumference of the sleeve in transverse position, a screw securing the center of said element to the sleeve and reciprocably mounted pins secured one at each end of each said element extending through the sleeve wail to points of contact with the wall of said stock and releasably heldin said positions by said spring element.

5. A device for forming a relatively long cylindrical length of' tubing stock into a chamber having the mid portion thereof possessed of the same cylindrical shape as said tubular'stock and having rounded, relatively closed ends comprising, a platen having an aperture therein includa short cylindrical section having the same internal diameter asthe external diameter 'of said stock adapted to iit around the end of said stock, an inwardly curved annular wall forming a bottom for said aperture, a second platen having an annular curved recess therein complementary to said rst recess including a short cylindrical section having the saine diameter as the external diameter of said stock around the other end of said tubular stock, said platens having an initial open position for insertion of the tubular stock, and having a limited relative reciprocating movement to and from compressed positions, an initial compressed position wherein each end. of the tubular stock '1S held within the respective short ,cyllndrlcal than the initial diameter of the tubular stock.

GEORGE E. FRANCK.

adapted to iit wherein the

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