US2604136A - Tube-forming machine - Google Patents

Description

" iolise July 22, 1952 B. M. NASE TUBE-FORMING MACHINE s Sheets-Shed 1 Filed Jan. 10, 194'.

INVEN TOR BENJA /NM N455 BY 'WMW%.

A TTOR/VEYS July 22, 1952 B. MNASE 2,604,136

' TUBE-FORMING MACHINE Filed Jan. 10. 1947 3 Sheets-Sheet 2 I INVENTOR flf/VJAM/N/M/WSE A T TORNE Y5 Paten d y 2 1952 perior Tube Company, Norristown, poration of Pennsylvania Pa., a corv I Application January 10, 1947, Serial No. 721,354 I 3 Claims. (Cl. 153-33) This invention relates to tube forming machines, particularly to machines for making tubular electrodes for thermionic tubes. '1

In the manufacture of tubular electrodes from blanks which are shapedpver a mandrel by bending, seaming and finishing dies, certain difliculties arise especially when the tubular electrodes are of flattened oval shape or similar cross section. For example, when the bending die is of the ,type shown in U. S. Letters Patent No. 2,116,971

to Haslauer, it is difficult in event of jamming at the bending station to clear the machine for prom t resumptionof normal operation; furthermore, when the finishing die is of the type therein disclosed, it is diificult to meet exacting requirements'of size and shape of the finished electrodes.

In accordance with the present invention, these difliculties-areovercome by use of the bending and finishing dies which each comprise a pair of die members complementarily recessed to embrace the mandrel and so mounted on the movable die-block structure thatthey are capable of restricted movement relative to each other upon engagement with a blank or tube on the mandrel. The bending die members are normally 2;

maintained in engagement with each other by a biasingspring arrangement which allows them to separate slightly in event of jamming at the mandrel: the finishing die members are held slightly apart by a spring arrangement whose bias is progressively overcome as the mandrel and tube thereon more and more deeply enter the die recesses. The improved finishing die arrangement is herein claimed; and the improved bending die arrangement is claimed in co-pending divisional application Serial No. 275,115, filed March 6, 1952. v

The invention further resides in features of construction, combination and arrangement hereinafter described and claimed.

For a more detailed understanding of the invento the accompanying. drawmachine in separated position;

Fig. 2 is a perspective view of the upper dies and illustrates the successive steps of forming finished electrodes from blank stock;

Fig. 3 is a perspective view of a finished tube or electrode? 'Fig. 4 is a sectionalend view on enlarged scale showing details of construction of the bending die and associated elements, the section of the die being taken online's 4'4 of Fig. 6

Fig. 5 is simila-rto Fig. 4 but shows the bending die in its lowermost position; V

Fig; 6 is an exploded view showing the elements of the bending die;

Fig. 7 is a sectional end View of the finishing die and associated parts; the section through the finishing die is taken on lines 01. Fig. 9;

Fig. 8 is similar to Fig. 7 but shows the finishing die inits lowermost position;

Fig. 9 is anexploded view showing the va elements of the finishing die;

Fig. 10 is a sectional view of the taken on lines l0 l0 of Fig. 9; and A I Fi 11 is a sectional view taken on line lll ofFig.9. V

Referring to Fig. 1, the upper die-block III which reciprocates toward and from the lower die-block H carries a blanking die 12, a bending die [3 and a finishing die [4. During each cycle of the machine, the movable blanking die 12 cooperates with the lower, stationary blanking die I5 to sever a tube blank Tl, Fig. 2, from a'thin metal strip S. When the electrodes are to be provided with a .bead, the beadingoperation may be performed by dies I2 and I5, or by a pairjof dies which operate upon strip S in advance ofthe blanking station. During this cutting or forming of a blank by the dies l2 and IS, the bending die 13 presses a previously cut blank over the mandrel 9 and before the return upward movement of the die-block, the bent blank is operated upon by the seam-forming and seam-locking tools lfi and l! to form a seamed tube T2 about the mandrel. The operation of the actuating members [8,Figs. 4 and 5, for the mandrel-supporting and seamlocking tool I! is fully described in the aforesaid Haslauer patent. Preferably, the lower-surface of the mandrel is grooved to receive the lock-seam formed from the margins of the blank by the tools rio s finishing die I 6 and I1. During'each cycle of the machine, the 1 finishing dies I 4 and 20 operate upon a previously tio nof the finished tube T4, Fig. 2, with eventual discharge of the tubes in succession from the free mandr l. 9,. n,.bending of end of the mandrel. The finished electrode T, when of the beaded type, is shown in Fig. 3. Concurrently with each forward or feeding movement of the mandrel 9 a carriage, not shown, pushes a blank TI from between the then separated blanking dies l2 and 5 to position below the bending die l3. Control of the blank is maintained during thistransfer of the guides or nest members 19, Figs.-4 and 5.

The foregoing brief description Of the general purpose and function of the various dies is.

In any event, whenever jammingoccurrei-extensire damage occurred and mu h me and laborwasreguiredagain to put the machine. into operation. Specifically. in. practically all cases of'jam-ming, thebending die, broke; and in most cases, in addition to breakage Of he die, th wasbreakage of one or more of the seameforming and locking tools and serious. deformation oi'the mandrel. From the fact vthat for smaller, sizes of the electrodesthem-inor andmaj'or. axes. of the, mandrel are respectively only about 0.030 inch and 0.10 inch, it can readily be appreciated the-ma hin pa ts mentioned must necessar ly lie-sma l. accurately -.c.limensioned and msci.sely posit on d. an tha th y arev inevitably broken or. serious y. dama ed it any jamm n occurs- .As. shown most cl arly inF ssland th pr sent bend n d als. which overcomes these diii'i u t es, compris s a pa r of. die members 2.2 and .23. Qomplementarily shaped at their lower end toformjtherecessfl which coasts withthe the. blanks and, formationpf theilock-seams, The positioning pins wliiizhgeistend from thejipper die-block [11 fit tightlyin openings 26 n-theQleft-hand die. member 22 and project'into thesomewhat larger openings 21 in the rightjhn lidig member 23. The pair of die: members 22, 223 are mounted upon the block member 8' for movement unison, therewith and for limited relative movement by an arrangement com-prising a pair of screws 2;8-, spring washers 3i and washers 32.. Eachf-thescrews ZB-passes through openings 29 and inythe die members 23 -and 22 respectively and into threaded engagement with the dieholder 8. The openings- 30 somewhat loosely fit the shanks ofthe screws: 28 to. allow precise determination of the'position of the die member 2 2 axially of'the mandrel. "Iheopenings 2-1-"and 29 in the right-hand die'member zfilhowever, provide greater clearance for thezpins; 2,5

and screws 28 for'additional reasons which. ;later 7 appear.

the detachable. portion 8 of the mandrel by the die members 22, 23 whose thrust during this blank-bending operation is received by the horizontal surface 24 of the dieblock member 8. Surface 24 is parallel to the minor axis of the mandrel 9 and engages the upper face of each of the die members 22, 23. The biasing forces exerted by the springs or lock- Washers 3:! are suificientlylgreat to maintain the members '22 and 23 immovably in engagement with each other during the normal bending, seam-forming and seam-locking operations performed at this station of the machine.

If, however, there is jamming at the mandrel, the springs 31 yield so to allow the die members 13- nd. zgtq. separate slightly, generally as shown in Big. The clearance afforded pins 25 and screws 28 by the larger openings 21 and 28 in the die member 23"permits it to tilt slightly to open; the; recess 1 and so avoids freezing of the die, mandrel and the tube. The heads of the screws. 2.8. for nutsif studs are used. instead of screws), serve as stops winch suitably restrictthe extent to which. the die. members-.22, '23. may be forced apart, whether thatseparationbe effected by the jamming itself or. byinsertionof. a. tool by the operator to permitihim to. withdraw from the machine the blanks or tubes causing the jamming. In any event, the extent of separation is ordinarily sufiicient to allow the machine easily to becl'eared so that normal operation may quickly be resumed without need to remove or replace, any of the dies or any of theseam-forming or locking'tools. 'W'hen the offending obstruction is removed, the springs '31 are at once effective toreturn the diemembersZZ, 23 to their original normal positions in engagement with each other, Fig. 4, and'the machine is in readiness for resumption Qf'ifiS operation. I

Referring to Figs. 7'l'0;"inclusive, the .mov'able finishing-die I i-also com'orisesa pairof'die members'movable vertically in unison with the upper die-block and" capable of lateral movement with respect to one another. The two die members 33 and 34 are com'plementarily shaped at their lower ends to form a recess 5 suited snuglyto receive a seamed tube 13' on the mandrel-9. The pins 35 tightly fit the openings 36' near. the upper endof the diemember-33 and project'into the largeropenings 31-in the die member 35. The pair of diemembers are heldparallel -to'aforesaid surface 6 of the die-block 8 by the" screws 38 which pass through the openings 39 and 40in the d e members 34 and 33 respectively. As indicated; the openings 39 in member 34 are substantially: larger than those-in-thedie member -33, the former openings affording appreciable clearance for the enlarged portions. of the shanks of screws 38 and the openings 40 affording clearance for the smaller shank portions of'the screws which. extend through the die-block member'fl'; the clearance afforded by enlarged openings 40 permits accurate positioningof the die axially of the mandrel; the greater clearance afforded openings 39 has the additional purpose later herein described; The aforesaid" ledge surface 24 of: block member '8- overlies the upperfacesof die members 33, 34* to-receivethe thrust incident to their coaction with-- the. mandrel and the lower finishing die 2}].

The spring 4| disposed betweenthedie members 33 and 34 and, preferably received: by the recesses 42 and 41 in the adjoining faceslthereof, Fig. 1.0, forces the-die members 33-and34.apart, generally as shown, in Fig. 7,. The maximum separation is determined by theheads. of*the screws 38, 38 Which-thussenve-asstops limiting for;ced apart by the spring 4i." When-thejdieblock is in its upper position away 'fromfthe mandrel the two finishin'g'die members "33 and 34 are separated, Fig. 7, the rightj-handdie member 34 assuming aslightly ,tilted'position determined by the specially tapered'or shaped: rear 7 face of the screw heads 38 thus to opentthe recess 5 so that its width is somewhat greaterthan the desired outer minor width of the finished electrodes. As the dieblock.mo'ves downwardly towardthe mandrel, the .outer lower edgesof the die members 33 and'34-engage thefixed cam surfaces 44 which are directeddownwardly and inwardly. As downward movement of the'upper die-block continues, the finishing diemembers 33 and 3 in addition to moving vertically with respect to the mandrel also move horizontally towards one another and toward the sides-of the mandrel to narrow the recess 5, coming into engagement with each other just before the end of the down stroke for the remainder of which the outer faces and the die members 33 and 34 are in engagement with the lower, vertical portions of the earns 44, 44. As the die-block moves upwardly, the spring 4| causes the die members 33, 34 again to assume their separated position, Fig. 7.

With the die members 33, 34 approaching their lowermost position, Fig. 8, the narrowing recess 5 and the shallow recess in the upper face of the stationary finishing die cooperate with the mandrel 9 precisely to determine the shape and dimensions of the finished electrode or tube. During this operation, the shaping pressure is well distributed over the entire tube area and is applied directly to the sides as well as to the upper and lower faces of the tube. This mode of dimensioning and shaping the seamed tubes on the mandrel 9 aifords results which are markedly superior to those attained with finishing dies of the type shown in the aforesaid Haslauer patent and is particularly suited for finishing of tubes of flattened oval or similar cross section including elliptical, oblong or other shape having unequal major and minor axes and has made it possible to meet very exacting requirements as to their shape and size; and without need to reduce the rate of production of the machine. With the die arrangement described, the major and minor axis dimensions of electrodes produced by the machine are within a tolerance of not more than one or two-thousandths of an inch.

As shown in the drawings and as above described, both pairs of die members 22, 23 and 33, 34 are attached to block 8 forming therewith a detachable die-block assembly which is attached as by bolts shown in Figs. 4, 5, '7 and 8 to the upper die-block ill. The faces 6 and 24 of block 3, as above described, align both pairs of die members with respect to mutually perpendicular planes which, when the die-block assembly is in the tube forming machine, respectively coincide with a vertical plane in which lies the longitudinal axis of the mandrel 9 and with a horizontal plane parallel to a horizontal plane in which lies the longitudinal axis of the mandrel: the positioning pins 25, 25 and 35, extending from the aforesaid face 6 of block 8 cooperate with the .pairs of die members to fix their proper relative position so that when the assembly is attached to the upper die-block of the machine they are simultaneously properly positioned longitudinally of the mandrel.

What is claimed is:

shall bonnders'to'od the -iiiventionis' not limited to the partioular arrangements spcifical l'y disclosed, but that changes *and modifications within "the -s ppe "of the appended claims may be made.

' 1*."A 'die block'asse'mbly for a tube 'forming mechanism comprisinga mandrel, a'di'e block movable toward and from said mandrel, a pair of normally separated die members carried by said die-block and having complementary recesses at one end to embrace the mandrel, and actuating means for producing relative movement of said die members toward eachotherasthey are moved into embracing relation to themandrel by movement for said die-block, said. die block. assembly .beipglcharacterized in ,thatjs'aid' die-block has 'a thrust receiving-surfacefor engaging the other ends of said die members and a positioning surface for engaging a side of one of said die members, in that locating pins extend from said positioning surface through said die members, and in that said die members are detachably mounted on said die-block by means comprising a member extending from'said positioning surface freely through saiddie members and having a head portion for defining the normal separation of said die members, and resilient means disposed normally to maintain aforesaid separation of the die members but yielding as they are moved by said actuating means to true a formed tube on the mandrel.

2. A die-block assembly for a tube-forming mechanism comprising a mandrel, a die-block movable toward and away from said mandrel, a

pair of normally separated die members carried by said die-block and having complementary recesses at one end to embrace the mandrel, and actuating means for producing relative movement of said die members toward each other as they are moved into embracing relation to the mandrel by movement of said die-block, said die-block assembly being characterized in that said die-block has a thrust-receiving surface for engaging the other ends of said die members and a positioning surface for engaging a side of one of said die members, and in that said die members are detachably mounted on said die-block by means comprising a member extending from said positioning surface through said die members and having a head portion for defining the normal separation of said die members, and resilient means disposed normally to maintain separation of the mounted die members but yielding as they are moved by said actuating means to embrace said mandrel.

3. A die-block assembly for, a tube-forming machine comprising a mandrel of cross-section having unequal major and minor axes, a dieblock movable toward and away from said mandrel, a pair of normally separated die members carried by said die-block and having complementary recesses at one end to embrace said mandrel, and actuating means for producing relative movement of said die members toward each other as they are moved into embracing relation to the mandrel by movement of said dieblock, said die-block assembly being characterized in that said die-block has a thrust-receiving surface parallel to the minor axis of the mandrel for engaging the other ends of said die members and a positioning surface parallel to the major axis of the mandrel for engaging a side of one of said die members, and in that said die members are detachably mounted on said die-block theyare moved by said actuating means to em- 'bmce said mandrel.

I YBENJAIVHN M. was? REEERENcEsJ CITED V The following references are of recnrd in. the

files of: thisppatent:

STATES PATENTS 7 Name Date 64,585 Schubeus May '7, 186.7

:Sept. 17,. 1367 69,060 Woodward Number 8 Name 7 Date I NortOn May 29;.1'906 Edwards Dec. 30, 419-13 Rehhein Dec. 5, 1916 Scott Nov. 30, 1920 Kloc'ke Oc.t.. 4, 1932 Graybi1L Mar. 13,1934 Haslauer May 10, 1938 Courtney Aug. 26-, .1947 Cahill June 22, 1948 FOREIGN PATENTS Country Date Great Britain of 1900 Germany May'26, 191.5 Great Britain Sept. 26, 1935 Great Britain ....V. Jan. 13', 194.4;

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