US2488896A - Dual pivoted bender for simultaneously bending two parallel lengths of metal tubing - Google Patents

Description

C. J. BERTOLINI ET AL DUAL PIVOTED BENDER FOR SIMULTANEOUSLY BENDING TWO PARALLEL LENGTHS OF METAL TUBING 5 Sheets-Sheet 1 Nov. 22, 1949 2,488,896

Filed June 14, 1946 INVENTOR. Omen; Jfiflzroz/M BY ffimey Mew 07/65 C. J. BERTOLINI ET AL DUAL PIVOTED BEN Nov. 22, 1949 2,488,896

DER FOR SIMULTANEOUSLY BENDING TWO PARALLEL LENGTHS OF METAL TUBING F-iled June 14, 1946 5 Sheets-Sheet 2 INVENTOR J557DLnw Nov. 22, 1949 DUAL PIVOTED BENDER FOR SIMULTANEOUSLY BENDING Two PARALLEL LENGTHS 0F METAL TUBING Filed June 14, 1946 5 Sheets-Sheet 5 Fig. 4

J. BERTOLINJ ET AL 2,488,896 I Nov. 22, 1949 c. J. BERTOLINI ET AL DUAL PIVOTED BENDER FOR SIMULTANEOUS LY BENDING TWO PARALLEL LENGTHS OF METAL TUBING Filed June 14, 1946 5 Sheets-Sheet 4 Nov. 22, 194 c. J. BERTOLINI ET AL DUAL PIVOTED BEN DER FOR SIMULTANEOUSLY BENDING TWO PARALLEL LENGTHS OF METAL TUBING 5 Sheets-Sheet 5 Filed June 14, 1946 INVENTOR.

CHmzLss 1294-7224/44 f/away l/4/V /KE 'chinery and particularly pertains to a bendin Patented Nov. 22, 1949 UNITED STATES PATENT OFFICE DUAL PIVOTED BENDElt FOR SIMUL- TANEOUSLY BENDING TWO PARALLEL LENGTHS or METAL TUBING Charles J. Bertolini and Henry Van Dyke, Pasadena, Calif.

Application June 14, 1946, Serial No. 676,740

6 Claims. (Cl. 153-40) This invention relates to metal working mamachine.

At the present time tubular metal furniture is in vogue. This furniture is characterized as having a frame structure bent from a continuous length of metal tubing. For example, chairs may be made with a metal tubin frame. This frame comprises a cross member at the top of the back of the chair continuing in vertical uprights for the chair back, after which horizontal lengths are provided to support the seat of the chair. The frame then continues in downwardly extending vertical leg lengths and foot or base portions. It is obvious that the finish and attractive appearance of a chair of this construction depends upon the symmetry of the lines of the frame and the uniformity of the parts since the two sides of the chair frame are in duplicate and any variation in lines or bends may be noticed readily. In order to form a tubular bend satisfactorily, it is necessary to measure the metal accurately and to attempt to bend the metal so that complementary curves at opposite sides of the frame will be substantially identical. This requires skillful manipulation of the metal and accurate measuring, thus producing high labor costs.

It is the principal object of the present invention to provide a bending machine within which a loop of tubular material may be placed and by which complementary curved portions of the frame may be bent simultaneously, thus insuring that said complementary curves will be identical and may be performed rapidly and at low labor cost.

It is also an object of the invention to provide means whereby the tubular stock may be measured easily and set so that the position of the bends may be determined quickly and so that operation on successive pieces of material will be uniform.

The present invention contemplates the provision of a machine which will receive a length of cylindrical or tubular metal bent upon itself to form two parallel lengths, the said machine being designed to simultaneously engage and operate upon both of said parallel lengths so that the materlal of both lengths will be formed with complementary bends of equal arcuate length. The invention is illustrated by way of example in the accompanying drawings, in which:

Figure 1 is a perspective view showing a chair frame of the type to be bent by the use of the machine with :which the present invention is concerned;

Figure 2 is a view inend elevation showing the machine and indicating the relative 'positionsof the tube bending heads and the drive clutch therefor;

Figure 3 is a view in side elevation showing the complete machine and indicating the spacing members and their relation to the bending heads;

Figure 4 is an enlarged vertical view in end elevation and section as seen on the line 4- 4 of Figure 3 and shows the bending heads, the drive therefor, and the throwout clutch connected therewith; 1

Figure 5 is an enlarged fragmentary view showing one of the bending arms in side elevation and also indicating the horizontally disposed supporting rollers upon which the tubing rests whilebeing operated upon;

Figure 6 is a view in plan as seen 'on the line 6-B. of Fig. 3 and drawn at substantially the same scale as Fig. 4, showing the fragmentary portion of the machine including the bending heads, the drive; and the stop switch;

Figure 7 is a view in plan as seen on the ,line 7-1 of Fig. 2 and indicates the two bending heads, the drive, and the control clutch;

Figure 8 is an enlarged fragmentary viewiin side elevation showing the end of the frame structure, the bending head mounted thereon, and its relation to the stop when the piece of work has been benttoa desired angle. V

Referring more particularly to the drawing, I10 indicates a sub-frame upon which a pair of horizontal frame members II are mounted. These frame members are shown in Fig. 4 of the drawing as being of channel section and as being secured together by tie plates 12. The length of 'thehorizontal frame members II is appropriate to accommodate the developed length of each leg of a frame'structure such as indicated in ,Fig'. 1 of the drawing. The sub-frame It! carries a transverse frame member l3 upon which a driving motor I4 is mounted. This motor is equipped with suitable connections to be hereinafter described,.for the purpose of transmitting power to a bending head generally indicated at I5 in the drawing. g

The details of construction of the bending head are shown more particularly in Fig. 4. Here it will be seen that the frame members 'll carry brackets l6 upon which bearing structures I! are secured by bolts I8. The bearing structures. I! are fitted with theusual removable journalcaps l9 held in place by cap screws 20.. The bearing screws are disposed adjacent to the opposed inner a die shaft 2|. The opposed faces of the bearing structures H are spaced a predetermined distance apart to accommodate a spiral gear 22. This gear is formed at one side with a hub section 23 which spaces the gear from the end of one of the bearings ll. The opposite sideof the gear 22 is fitted with a jaw clutch element 24. It is to be understood that the'ge'ar 22 is married to rotate freely upon the die shaft '2 The gear 22 is held against longitudinal movement upon the shaft by suitable means not shown if} m? firawmga Splined upon the shaft 2| is a-jaw clutch elenr'ent 25 which is complementary to the jaw clutch member 24 carried by the gear 22, The jaw clutch member 25 is formed with'a shifting'iin g 26 which receives pins 21 carried by the arms of a shifting fork 28. The spline structureis fiidu cated at 29.

It will be obvious that when the jaws 24 and 25 are movedinto mesh, the gear 22 will drive the die seen 2 1. The "srii erg a 22 is inn'iesh with a wdr'if'gear pinion 30. This pinion is "carried 'updn a horizontally extending 'drive f hait al which mounted in journal blocks 32. The blade s'z arebairried pon the ti -mates 12 of the frame fstrutii'ie. The pir'iion30 is keyed to tire f's haft "3 as indicated at "33, Tlie shaft is eeiive iiig auy connected to 'the motor |'4 "so that wiin e dr nthereb'y. w y I I I Mbu'r'i'ted'upon thefdi'e' shaft 21 at'oppo'site s ides or the frame structure 11 are "circular "bend n d ies34. These dies arekeyed to and=rotatedby thesha'ft' '2 "e iid "are "formed 'with a circumfere ove which "is substantially semi-circular n ss-se'cti'on,'saidsection being described'by a. radius representing oiie h'alf'tlie' outside ameter of a piece of material tobe bent. Fixed jiiienii esiie' i 21 at'opposite'sids er 'the'dies Iiilfaiid "'ye'd't'e tiif "shaft'a'fe bending arms 35. These; assnewn'in Fig.5ofthedralwing, are new iiip ecety keys 21 "WhiGhpositi'wfeIysecure them with'jieiation tb'tneshaft-1|. "The a fare fof "a length "tobverhang 'the referee; eitnejbenaiiig" iesaa' a'sufficier'it distance to acconifiio'd ite'ajo'ending suoe'ss'end aireeceiif ti'" am ao therefor, The

en e h' fi q l e'fl t i agafiistuie iimer raees ef'the'eriiis at, tom face, 33l rests against "a'fl'atfportion3'9 fbfsaid jzatnill. 'rrii cjm ijs fittedwitha nendieal and asit is r t'ated" move tnej hee sef na en"- iie'rto be Hereinafter described. Extending op- 1y"fr6m t1ie*out net face's'oftlie sneeze fare pins 4 2, These pinsegitend through s16 tsf43 in theiarn sss, the s'lotsextnding radially'offthe "Bf the "die 'Sh'aftil and 'in the Sallie 'aiiial plane as the "shaft "2| "and a pivot pin "4'4 "u on hichfthe c'ain lllissupportedrotatably.

Tll'e' face breech of thefshoes 36 whichfis'pfeeejritea toward the axis" or "theishaft '2 is termed fw'i th "a "cerium longitudinal groove complirfntaryitb the 'grccv 'i'ntli'e circumference "of "the ben ing diese T 'us'whena'shoe 36isinoyed 'ifito proximity to the circumference" of a "die 34, .a pass ageway will be formed which accemiiietes'f tlie circumference: of a "member: to "be bent Endsiibstantially agrees therewith. V This insures tl'fat'the circumference or the meihterie be bent will be "embraced completely by 'a shoe 36 and a dief'34 in "a plane "of contact, whichplane :lies radially -"ofthe axis of the'die shaft- 2| and win en 'pgee the armsiiii swing upwardly. v

Mounted upon a transverse frame element "45.

element 'tical with that previously described as being for'inedaround the circumference of the dies 34. In the present instance the rollers are disposed beneath -a length of tubing stock 50 upon which bending operations are to be performed. The adjusting screw 41 makes it possible to raise and lower the rollers 49 so that the length of materia-liifl will be properly supported and guided to andbeneath the circumference of the bendin dies 34.

A In order to properly guide the piece of tubular stock 50 and to insure that the tubingfwill be bent'without crinkling or ScratchmgQnian'drel'S '51 are provided. These mandrels extend longitudinally'of the outer sides of the frame members ll. Each of the mandrels has a rod portion 52 'which'extends through a plate 53 and'i's heldin position by nuts 54. The opposite end of "the mandrelbl is formed with a large'cylindricalportion 55. The outside diameter of this portion agrees substantially with the inside dialint'rbf the tubular StO Ck 50. The length bf the Iii E e mandrel 'portion55 is 'siifil'cient to 'eiiten'd across the tops of both of the rollers 49 and totrr'riinate slightly beyond theradi'alvertical "plane dccupie'd by them. The outer end of theportion'55 df'the 'mandrels 5| is hemispherical so that jsufiicie'nt clearance Will beprovi'ded for the tubular stock 'as'it iswrap ped around the dies 34.

M Disposed parallel to the mandrels 5| and supported in bearings 56 are measuring rods 57. These rodsare fitted with a plurality of adjustablestop members 58. The stop members are formed with fingers 59 which extend downwardly to a point b neath the level of the mandrelsidl and lie thereagainst to provide an adjustable abutmentfor a piece of'st'ock 5fl which telescopes over the mandrels'fil. The stops 58 are-mounted sli'dablyupon'the rheais'dririgiddsbl and may be held in position by 'set serewsao and maybe swung selectively into the pain of travel of the en C1 Of the piece of stock 58.

chair frame structure generally indicated 'a't BI, 'ade'irorn tubular StockEGQis shown'in Fi'g. l. Whileit i'sto be understood that variousarticles might be formed by a machine embodying thef'presentinvention, 'a chair -fra'inewill"be "described by way of example. 'fiiichafi'arrfe may :h'ave'feet or runnerpo'rtions 62 Whichfet ripen the floor and whichattheir foiward n'ds continue in curved portie'n'sta These curvea'i'pcrtions represent substantially one-quarterbf a circle. The tubular stock isthen bent upwardly to form legs 6'4. These legs" are preferablyat right angles to the portions'ES'Z. At tlie'up'per jen'cl'of the legs are curved'portionsiii which continue in seat lengths 65. These lengths are pai allel to "each'ot'her and lie in thesa'm'e 'yeiti'cal plane as therunners 62. They arealsjo disposed l'above these runners. The seat lengths "of the frame continue in curved portions 61 'upxvafrdly from which the 'back 'portionsffia-extnd. The ba'ck portions "68 "are 'curvedat'fthei'r upper'ehds "as 'in'dicatedet '69, *the' curves" being c'o'rinlecte'db'y 'atransver's'e back member 10. "It'is"'tobe ufziderstood that fabric panels may be stretclid-'between the back members 68 and also between the seat members 66. It will also be recognized that while the runners 62 and the legs 64 are here shown as disposed at right angles to each other,

vgreater or less than 98.

When a length of material is bent to form a frame structure, such as shown in Fig. 1, it has heretofore been common practice to make each of the bends separately. It is obvious that in view of the variations which might be required in the radius of the bends as Well as the arcuate lengths of the bends, care and considerable time is required in order to insure that the bends are of proper configuration, and furthermore that the complementary bends at opposite sides of the chair are identical. It will also be recognized that in the event these bends are not identical in angle and in length, the intermediate straight lengths of material will vary so that the frame .Will lack symmetry. In the machine with which the present invention is involved, the lengths for the various portions of the frame are readily established by the stops 58. In order to insure that the arcuate lengths of the bends shall be uniform and of desired configuration, novel measuring means have been provided. This includes a stop member 1| shown in Fig. 3 of the drawing as comprising a triangular block 12 having stop faces 13, 14 and 15. The block is mountedto rotate upon a horizontal shaft 16, the axis of the shaft being in such a relation to the faces of the block 12 as to cause each of the faces to be spaced a different selected distance from the axis. Thus, when the block 12 is rotated upon its horizontal axis, to dispose one ofits faces in a vertical plane, that face will have a definite spaced relationship to the axis of the shaft 2|.

Since the stop block 12 is disposed'in the path oftravel of the tubing stock as it is bent upwardly and around the bending dies 34, the stop structure 11 will act to determine the amount of bend which is given in each bending operation. When the stop block 12 is encountered by the swinging length of stock 58, it is intended that driving operation of the motor l4 shall be instantaneously interrupted. The structure for accomplishing this is a lever arm 11 which is fixed to the pivot shaft 16. This shaft is in turn locked to the stop block 12 by means such as a set screw 18. The lever arm 11 extends downwardly and carries a horizontally extending arm portion 18 the arm portion being guided through bearings 19' which permit the lever arm 11 and the arm to move longitudinally. At the free end of arm portion 19 is a saddle 88. The saddle 88'rests upon an actuating lever 8| of a micro-electric switch 82. The switch 82 is included within the electric circuit of the motor I I to interrupt the same instantaneously. A main control switch '83 is also placed in the circuit so that the electric circuit may be completely broken when required. .When it is desired to disconnect the driving head from the motor 15 mechanically, the shifting fork 28 is actuated. The shifting fork 28 is mounted upon a bracket 84 carried by one of the frame members II. The fork is pivoted at '85 and is formed with an operating handle 86 which extends forwardly and then transversely of the end of the fram members ll. Thus by pushing on the handle 88 in the direction of the arrow a, as shown in Fig. 6, the clutch may be thrown out of engagement. An arm 81 is formed as a continuation of the shifting fork 28 and extends horizontally therefrom upon the opposite side' of the handle 86. This arm is fitted with a tension spring 88 which tends to hold the clutch member 25 into engagement with the clutch member 24. A latch 89 is provided at the forward end of the frame structure I l and is mounted upon a pivot pin 98. This latch may swing into the path of the shank of the clutch handle 86 and will act to hold the clutch 25 in its disengaging position after the lever 88 has been depressed.

In operation of the present invention, the structure is assembled as shown in the drawing. An article, such as the chair frame indicated at 61, is to be made and a suitable piece of tubular stock 58 is selected for the purpose. The machine is then set up for operation. Before doing this, the character of the metal stock must be considered, as well as its wall thickness and its ductility. When these factors have been determined, the mandrels 55 are adjusted by the nuts 54 which are threaded onto the outer end of the rod 51. This longitudinal adjustment places the spherical ends of the mandrels 55 in a desired relationship to the vertical center plane of the bending head. The piece of stock 58 has been bent previously to form the complementary bends 69 at the opposite ends of the transverse back portion 18. It is to be understood that the two lengths of stock continuing from the bends 69 are equal in length and are straight and parallel. The free ends of these lengths are then slipped over the mandrels 55 and moved to an abutting position against a selected one of the stop fingers 59, the other stop fingers between the selected one and the bending arm being swung out of the path of said lengths of stock. The adjusting screws 41 ar then moved to place the supporting rollers 49 in proper position beneath the tubular stock, and so that the upper face of the tubular stock will seat within the arcuate groove 34 of the bending dies 34. Thereafter the lever arms 4! are swung to rotate the cam members 48 around the axes of their bolts 44.

As these cam members rotate, they will lift the shoes 36 and force them upwardly so that their arcuate grooves 36' will conform to the under face of the tubular stock 58. When this adjusting has been completed, the nuts 44' are tightened to hold the shoes 36 in their set positions. It will be recognized that when the tubular stock 58 has been properly mounted upon the mandrels with the ends of the stock abutting against suitable stop fingers 59, a desired length of the frame will project beyond the end of the machine a distance representing approximately one-half of the bend to be formed plus the length of a straight portion associated therewith. The stop unit 1| is then adjusted to rotate a suitable face 13, 14, or 15, into a plane slightly inclined to the vertical, after which the motor circuit is closed through control switch 83. This will cause the shaft 5| to berdriven and it in turn will drive the worm gear 38 and the worm pinion 22 in mesh therewith. The clutch members 24 and 25 may then be placed in engagement by lifting the latch member 89 so that the spring 88 will urge the clutch member 25 into engagement with the clutch member 24. Thus the shaft 2| will be rotated and will swing the arms 35 in the direction of the'arrow c as shown in Fig. 3. As these arms "swing upwardly, they will wrap the stock 58 stop stmdture When that takes lila'ce xhe face of the block 1-"4 =which' hasfloeen engaged'wiin be 'inove'd towards a tru'e vertical plane and'the lever arm M will be moved longitudinally to operate the micro--' the motor circuit. mnis-eireuiteannot be a'gain established until a relay switch is closed. Such a structure may be associated with theczitofi switdh'83. 'When the nextbend isto be made, the stock 50 is moved 'lonfgitt'ldinal'ly df-the members 51 until the :encsor the stock encounter the stop fingers -59. In the event that a:difierent de gree of bend is required, the stop block 12 is r'o tated upo'n the pivot "shaft 16 and is set so that it will be fixed with re'l'ation to the s'haft. Jinother bending operation-may then take pfl'a'ce and "these operations -may be -continued un'til the frame has been formed completely.

It will be obvious that thewid-th of the structure as represented from the distance between centers of the grooves in th'e bending dies '34 ni-a'ry be selected to accommodate a desired piece or work, since the bending dies perform a duplicat'e operation at each 'side o'i them'achine It will thus be 'seen that 'the machine' here disclosed is compact indesign andcons'tructi'on and that it provides 'means whereby duplicate bends of a desired radius "and degreemay be made simultaneously and the entire operation carried on in a semi-automatic manner.

While we have shown the preferred form "of our invention as now known 'to '11s, it is -to be understood that various changes may "be 'ma'de in the combination, construction and arrangement of partsjby thoseskilledin the artywithout departing from the spirit of the "invention as claimed.

Having thus "described our invention, what we claim and desire to secureby'LettersPatentis:

"l. A machine "for bending 'a tubular 'nietal "blank, which'bl'ank is initially bentuponitslf to form equal parallel "le'g sections, said machine com-prising, amain frame, "a'pairof mandr'elsex- "tending longitudinally thereof :and fixed at one end thereto and over which-the parallel portions of the blank telescope, "m'ea'nsfor adjusting the effective length of said mandrls, "the'opposite ends of said mandrels being "free, supporting means for the "blank adjacent the'ireeiends of the mandrela'a pair of die heads, -ne supported by the frame 'in .a p'lan'e'to receive"the tubular stock dfa'leg f sai'd'blan'k, each of saiddie'hea'ds comprising a circular die having an arcuate groove, the bottom of which groove-lies tangenelectric switch n and break effective length of said mandrels, the opposite ends 0f :said mandre'ls being fre'e, supporting means itor the blank --'adjacent the free ends o'f :thernandrels, a pair of die-heads, one supported ny theframe in a plane to receive the tubular stock Ofa IEg-Of said blank, each of said die-heads comprising a circular die ,having an arcuate groove, the bottom of which groove lies tangentially with the surface of the tubular blank,2a shaft upon which said dies are mounted, bending arms associated with each of said dies adapted to Swing around th axis of said shaft, a bendingshoe carried 'by'each of said-arm'srand being ier-med with a'longitudinal groove of arcuate-section complementary to the circi'ilar groove on the bending 'di'es' whereby the tubular metdl stoc'k may "be'enibra'ced in said complementary -grooves,'means'for setting said shoes in a desired fixed=position upon the bending 'armsgpoweruiriv- 1) ing-means for said die headsand amanually-operable clutch between said power driving means and the diehead shaft.

3.-A machine for bending a tubular metal blank which blank isinitially bent upon'itself to 'form equal parallel leg sections, said machine comprising, a main frame, a pair of 'mandrls 'extendinglongitudinally. thereof and fixed alt-one end thereto and over which" the parallel portions 0f the blank telescope, means for adjusting the "enec'ti-ve length of said mandrels, the opposite ends of said *m'andrels being free, supporting means for the blank adjacent the free *ends of the mandrls-a'pair-of die'heads, one supported by the frame in a plane to receive the tubular "stock o'f-a'leg 'o'f said-blank, each ofsaid die-heads comprising a circular die having an arcua'te "-groove, the bottom of which groov lies tangentially 'w'itlfthe surface 'of the -tubular blank, a shaft upon which said dies are motmtedfiben'ding ar-ms associated With each "of-said dies and adapted to=swing around theaxis of-said Shaina bending shoe carrie'd by each of 'said arms and being formed with 'a'longitudinal groove o'f arcuate section complementary to the circular :groove e bending flies whereby the tubular metal 'stock' may be embraced 'in said complementary groovesymeans for setting said sho'es in a desired hx'e'dposition upon the bending arms; an electric mo'tor for drivingsaid die hea'ds, a gear train between the =e'lectric motor and the die ="heatl shaft, and 'a normally set clutch for establishing weaving "connection between'said geartra'in and said die head shaft.

-4."1h'e combination of parts as set "forth in tially with the surface of thetubiilar'blank, az 3 n luq a y co dl e k shaft upon which said dies are mounted bending an olding the clutch in its disengaged armsassociated with each'of s'aiddies anda'dapt- "9 ed' to=swing aroundthe a-iiis (steam "s'hdfda'bend- 'in'g shoe carried by each of said arms an'cfbin formed witha longitudinalgroove .of iarcuatesec- =tion com-plementary-tdthe-circulargroove onlthe bending dies whereby the tubular metal .stock may baembraced in-said complemeritarygrooves, means for setting said shoes 'in =adesired 'fixe'd rposition upon the bending arms, means for =ro- :tating theshaftupon -which the'bendin dies are mounted and a manually actuated clutch -dis- :posed between-- said rotating means and-the shaft.

2. A machine for bending a tubulz r :metal blank vwhich blank is initially bentuponiitselfato :form equal parallel leg sections, said .machine comprising, a main frame,a pair of -mandrels extending longitudinally thereofand fixed at one -end thereto and" over which the=-parallel portions of the blank telescop e, --means :for-adjusting-the 1 5. Thestructure as set forth 'inelaimg "'cluding, "stop means interposed in the path "dt :45 straight legs of equal length, which machine comprises, a horizontal elongated main frameto be straddled bythe "tubular blank 'With"the leg .po'r'tions extending'a'long oppositelsides of said drama and the en'd ben'd extendingaroundthe E l'for ward end of the frame, apair of longitudi- .nall-y extending guide rods secured at'the rear end of the "frame and extending 'horizontallyto terminate adjacent'the forward end of the frame, cylindrical mandrel sections carried upon the 'free ends of (said-rods, said mandrel sectionsterminating in a hemispherical end and agreeing substantially in diameter with the inside diameter of the tu stock, a transverse horizontal shaft rotatably carried by the main frame jacent its forward end, the longitudinal axis of said shaft lying substantially in an equatorial plane of the hemispherical ends of said mandrels, bending dies mounted upon the ends of said shaft and being formed. with a circumferential groove, the sectional contour of which substantially agrees with the upper portion of the tubular stock, bending arms mounted upon said transverse shaft, adjacent to said circular bending dies, adapted to oscillate around the axis of said shaft, bending shoes carried by said bending said shoes being formed with a semicircular groove complementary to the semi-circular groove in the bending dies whereby the tubular blank may be substantially embraced by a shoe and a die, means carried by said arms for adjusting the shoes radially on the arms, supporting means carried by the main frame adjacent to the normal lowermost positions of said arms and upon which the legs of said tubular blank rest and are guided, and means for simultaneously swinging the bending arms around the axis of the bendin dies whereby engaged lengths of the legs of the tubular blank will be simultaneously Wrapped around the circular bending dies for a desired angular distance, and stop for determining said angular distance.

CHARLES J. BERTOLINI.

HENRY VAN DYKE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,376,441 Kamper May 3, 1921 1,502,633 Holmgreen July 22, 1924 1,546,147 Skinner July 14, 1925 1,849,181 Francis Mar. 15, 1932 1,993,799 Wagenbach Apr. 18, 1933 2,171,907 Beehler Sept. 5, 1939 2,236,255 Brooks June 16, 1942 2,312,121 Parker et al Feb. 23, 1943 2,357,812 Duer Sept. 12, 1944 FOREIGN PATENTS V Number Country 7 Date 72,895 Germany Jan. 10, 1894 263,657 Great Britain Jan. 6, 1927

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