US2342745A - Bending machine - Google Patents

Description

Feb. 29, 1944-. MAIZE 2,342,745

BENDING MACHINE Filed July 10, 1940 3 Sheets-Sheet 1 A gfi Z? n INVENTOR 72H] BY a @L/QM P 1 ATTORNEY Feb. 29, 1944. P. FQMAIZE 2,342,745

BENDING MACHINE Filed July 10, 1940 5 Sheets-Sheet 2 INVENTOR Pk! Ma z ze ATTORN Ya Feb. 29, 1944. P, MA|ZE 2,342,745

BENDING MACHINE Filed.July 10, 1940 3 Sheets-Sheet 3 made movable.

Patented Feb. 29,1944

UNITED GFF :BENDING MACHINE "PaulLF. Maize, Detroit, Mich, *ass'ign'or to Briggs "Manufacturing 'Company, Detroit, "Mich a corporation of 'Michigan Application July 10, 1940, Serial "344,760

24 Claims. (Cl. 153- 40) This inventionzrelatesiao 'bending ma'chinestand more particularly to :such machines :adaptedffor bending to desired curvature relativelyilongpieces "of :stock.

"Bending of relatively long pieces 1170 Narious :shapes, particularly ito :closed ifigures, "does not present difllculties when 'such tfigures approxi- -.mate a .circle "or, as it is often zexpressed {in the 'trac-k or groove provided thereon. Greatdifiiculties arise, however, where the desired shalivesinclude relatively sharp corners *ortu-rns, "andfirelatively straight portions betweenthem. If it is attempted, for'in'stance, tolierrd a 'relatively' flong workpiece "to a substantially rectangular "shape, after the-pressure shoe passesa corner, the pressure between the shoe and the "workpiece is first considerably relieved, "but after the pressure shoe reaches a certaimpoirit onthe *straightside of the workpiece (usually the middle thereof) the pressure "begins to increase and "also 'to change its direction tending to press on the pressure "shoe sideways with :an increasing force. In many-instances because of the friction involved the "pressure 'shoe soon becomes unable to move in "its intended path of'travel, since it'is pressed transversely with respect to said path, and breakage in the machine becomes inevitable.

It has been attempted to solve the above difficulty by providing means which 'in addition to rotating the forming plate also move it "bodily along various paths. However, structures fembody'in g such solutions are very complicated :and expensive .to build. lnxaddition, each machine is constructed for one :shape only and cannot be used for :other -shapes. Inmany cases :a machine :of the above character requires :an investment of several "thousand dollars and :yet it can he used for bending :a workpiece'toasingle form or shape.

One of the objects of the "present invention is to provide an improved :hending' machine for bending relatively long work-pieces such, 01 .in-

stance, as'wi-ndow frame moldings for motor vehicles, to desired shapes.

Another object of the invention is to provide an improved bending machine which can he used for producing various hentsshapes with on'lysslig'ht I replacements .in the operative parts of -the machine.

'A further object ofthe invention *is .to :provide a bending machine in which there are provided improved means for actuating \theiform plate-and the 1pressure=shoe along-an iimproved math, where by very -.complicated movements sof :the form plate :and mechanisms producing such movements in conventional machines are largely eliminated.

A still further object of tthe invention is *to provide an improvedibending machine :having a rotatable plate and a pressure shoe adapted to he maintained in an operative contact with the workpiecea'andractuated with respect to-said plate in such azmanner that 'only rota'tion 0f the plate is necessary :r-for bending work-pieces :to various curvatures and yet rno excessive side: pressures on the shoe occur atany time during the operation cycle.

Aistill :turtherobjectnf the=invention is to 'prowide an improved bending machine for bending l 'elatively long :pieces rto fshapes having relatively .sharp turns wor corners, without producing ob- ;iecti'ona'bly high unit pressures'ihetween the pressure shoe and the workpiece.

rI-t is -an added object of the present inventio to {provide a bending machine of the foregoing character, which is :simple in construction, dependahle in operation and relatively inexpensive to manufacture.

Other objects and advantages o'f thisinvention will "appear in the following description @and appended claims, reference being had to the accompanying drawings flforming a part 'of this specification wherein like reference characters designate corresponding parts in the several views. I

Fig. .1 is a front view 'o'f the bending machine embodying the present invention, the machine being shown ready toibegin its operation cycle.

Fig. 2 is an end view the machine .of Fig. 1, the observer being presumed to look-on the righthand fSi'Cl there'o'f. I

Fig .3 is fragmentary :seetional view takenin the direction of the arrows :on the section .plane passing through the section line 3-3 of Fig. v1.

Fig. 4 showsa workpiece as it is removed from the machine after the completion of 'thebending operation. i

.5 'is an enlarged transverse sectional view of the workpiece, said view being taken in the direction the arrows on the section plane passing through the line 5-5 of 171g. :4. Fig. 6 is .a diagrammatic view illustrating the hydraulic circuit operating the pressure shoe actuating means, and the electric circuit controlling said hydraulic circuit, the parts of the machine being shown in positions for bending movement (to the right) of the pressure shoe.

Fig. 7 is a view similar in part to Fig. 6 but showing the parts of the machine in positions for idle movement (to the left) of the pressure shoe.

Before explaining in detail the present invention it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation, and it is not intended to limit the invention claimed herein beyond the requirements of the prior art. In the drawings there is shown, by way of example, a bending machine embodying the present invention. The machine is shown and hereinafter described as adapted for bending a window or garnish molding for a motor vehicle. It will be understood, however, that the machine is applicable for bending workpieces of other descriptions and having different types of curvatures than those herein illustrated and described. Referring to the drawings and particularly to Fig. 1' thereof, the machine illustrated therein comprises a base III on which there is rotatably mounted a forming plate II of a shape substantially corresponding to that of the finished workpiece. The forming plate II is provided with a peripheral track or groove Ila (see Fig. 3) adapted to receive a workpiece I2 as the same is forced into said track for bending. Means are provided for locking one end of the workpiece I2 to the forming plate II, said means being exemplifled in the present embodiment of the invention by a hinged bracket I3 brought into locking position by a handle I4 as illustrated in Fig.-

3. As can be clearly seen in said Fig. 3, pushing the hand e I4 away from the plate causes the bracket I3 to press on the workpiece I2, thus holdin the same securely to the forming plate II Pushing the handle I4 toward the forming plate II unlocks the bracket I3 and the Workpiece I2.

The forming plate II is secured to a shaft I5" journalled in the base In and driven from the motor I6 through a speed reducing device II. In the machine illustrated in Fig. 1 the forming plate rotates in a counterclockwise direction.

It is an important feature of the present invent on that while the forming plate II is adapted to rotate around the fixed axis of the sha t I5, apressure shoe I8 cooperating with the track IIa of the forming plate is movable not only toward and away from the forming plate I I, as is common with conventional structures, but is also movable intermittently along the forming track I Ia. In the present embodiment of the invention such movements of the pressure shoe I8 are effected with the aid of active means adapted to produce active forces and to move said pressure shoe simultaneously in two substantially perpendicular directions.

In the present embodiment of the invention said meansare exemplified by a head frame 20 slida'ble in guideways formed on guide blocks 2| provided on the base I 0. The head frame 20 is actuated with the "aid of two opposing cylinders 22 and 23 mounted on the base ID. Said cylinders are provided" respectively with'fiuid' actuated pistons 24 and 25 connected to said head frame 2!] with the aid of piston rods 26 and 21, respectively. It will be understood that as the fluid pressure in cylinders 22 and 23 varies the head frame 20 will slide along the guideways 2|. It is preferable to use liquid for actuating the pistons 24 and 25 in order to attain quick starting and stopping of said pistons.

The head frame 20 carries a head 36 slidable in guideways 3|, provided in the head frame 20, in a direction substantially perpendicular to that of the guideways 2I. The head 39 carries the pressure shoe l8 which shoe is connected to said head to receive bending pressure therefrom. The pressure shoe I8 is adapted to rock on the head 30 within predetermined limits. Return of the pressure shoe I8 to its normal position is ensured with the aid of two springs 32.

Means actuating the head 3b are exemplified in the present embodiment of the invention by a cylinder 33 provided with a fluid actuated piston slidably fitted therein and connected to said head 30 by means of a piston rod 35. The cylinder 33 is provided with conduits 36 and 3?. By admitting liquid under pressure through one of said conduits, using the other as an exhaust conduit, it is possible to move the head 30 and, conse quently, the pressure shoe I8 toward and away from the forming plate II as desired or to cause the pressure shoe I3 to remain in pressure contact with the forming plate II irrespective of whether said plate II is stationary or rotates around its axis. Conduits 3B and 3! may be provided with proper control valves or plugs (not shown) which may be either manually or automatically operated.

From an examination of the drawings, an particularly of Fig. 1 thereof, it will be understood that since the plate I I is not of the circular form, should the pressure shoe I8 be in contact with said plate while the same rotates, the pressure shoe will move along a path parallel to the axis of the piston rod 35. With forming plates substantially conforming to a circular shape and having very small variations in the rate of change of the curvature thereof, which is-to say, having no relatively sharp turns, bending of a workpiece may be effected by merely holding the pressure shoe against the plate as the same rotates, or moving the pressure shoe along the forming track or groove if the forming plate is stationary. However, when, as in the present instance, the forming plate is of such a shape that bending has to be done around relatively sharp turns or corners, the unit pressures between the pressure hoe and the workpiece in places along the, forming track may assume directions transverse to the direction of pressure exerted on the pressure shoe, and in some cases may become perpendicular thereto. Under such conditions bending of the. workpiece becomes extremely diificult and v a breakage in the pressure shoe actuating means may result. Even if a machine is constructed strong enough to withstand such objectionable 65.

means are provided with the aid of which the pressure shoe I8 is moved along the forming track by means separate from those exerting bending pressure on the shoe I8. In the present embodiment of the invention said means are 'exemplified by the above described hydraulic meanszin ludinazqrlinders 12:2 sand .13 with {h rection :and substantiallyperpendicular to &the :axis. :of rt-hepiston rod .85. ,'I%hus, ;in efiect; the

pressure 1 shoe 1- !:8- is capablecofr'movingiinmanyxdiqrection, in the :plane; of :rotation of zthe :iormin plate I l ;and-.:remain at-.the:;same .time :in: pressure contact with the workpiece.

The ;-hydraulic circuit controlling :,the 1movemerits :of :the head :frame 220 i is illustrated {d191- grammatically in;Eigs.:-6 1and7. :Aszshownihrsaid fi ures; it: comprisesa :source :of1fluidipressnre l-4 t Qonnectedzby :means of.:awconduitq i l with :;control :cylinders Y42 and :43cimwhich cylindersrthereare siidably wfittedisuitahle valves, in the present":- instance rrecessedipistons idkand: r5. :Byrmeansni compression ceoilzsprings 45 and 1:47, the pistons -:44.,and.-45.ar e:rhe1d in theiruprights:ositionsmnless-some externahmeans, ?such 'as roolenoids 143 sands-4.9-inrthepresent:instance,1wbring them down against the opposition :of the respective csprings. When ,eitherwof-the;recessed;pistons; isjnrits, down 'positionit connects "the; source-:46 withna .respective head ,iframe actuating cylinder.

In the position of operative parts;.illustrated in Fig. 6,-the'fluidpressu11e from'thegsource 4!) is transmitted through ithe :conduit=;4 i: toithe-controlcylinder :43tandrtherefrom through the. conduits 556a: and '.50b :to .the leftahand portions {of the cylinders 3:22 {and 23. :Underisuchrconditions pistons :24 :and 2 5 :moVe :toithe right,1 ,ther,eby moving the? head: frame 52 0 rand, :consequently; the

headjifliandtthe' pressure shoe: 118;;carried thereby,

toxthe'right. If undercsuch conlditions theregis sufiicientnfiuid pressure ",in theupper portion :of the cylinder'i33 :;-tozexertapressure hnrther shoe 1-8, saidishoe willymovezto the rr-ight :along therforming plate track. .rremaining :at :the same rtime :in

contact :withwthe'workpiece i2. 'fi'lhetabove described condition :is one -:that (takes: place :at vthe "beginning f the :oneration :cyole. j ,It' wi-ll; b61111- derstood:.thatr.the commencing operation cycle presumes inserting the workpiece 12 into the forming track-.andvlocking'one end thereof; in said tracleas previous-ly::described -:and as: il'lustrated in Fig. 3, "admitting:fluidcpressure gthroughithe conduit 3,6:into the cylinder 3.3sandysettingtheplate i l to rotation. Means'qare providedtwhereby'said operations may be performed neither simultaneous1y= or successively. However, i such means are well known in the artvanfdfitherefore, detailed description thereof is not [deemed necessary-in the present instance.

The down position of the *recessed: piston :45 r as well as the upwardpositionaof the recessed rpistonit is ensured under :the rdescribed condition by energizing the solenoid #49 :and -:deenergizing the solen0id:48. 't-saidz-solenoids are relectrical-ly connected to .:a suitablesource Oi 7191801313 aenergy 50 and are controlled "by ax spring aloade'd two -.way

;-;provided win the @cylinder 53.

:as soon-gas :the :machine is ,started the .mressnrezshee 11:8 ;:moves 21201213118 wright along the :zstra ehtzportrionrfifirottheifolimihg track :provided .:on;t .1e ;plat:e-l'l. '.:Sinc e::no; b.ending takes place 5 g; in gsuchsagmovementz thekzsame is. relatively. rapid.

--Atithe::end .of saidcmovementa finger 5H0. con- ""t cllsficpinfi'l onzthegformingmlate. inrconseqllence whereofztherswitchfil isoperated to ,break the circuitenelfgizing thesolenoidAQ andto close the mmirouitienergizing.the-zsolenoid1.43. Such acondition is illustratedrimFigt'i. Whemsuch operaitionzoflthe:switohoccurshand thesolenoid 48 is ..energiz.ed, the :recessed piston 44 moves down a ainst :the resistance-hf the; spring :46 providing 1a ,commctionhetween:the source .40 through the icondilits 4 I 53 ;and:;5fiazwithz therright-hand portions of the head framega'ctuating:cy1inders22 --and :23. Deenergizing-of the solenoid 4!! occur-- 5 ring underzsuch' conditionspermitsthe spring '41 i to move gthevpiston.4.5:upward1yinterrupting the qeonnection rhetween the :source 48 and left-hand 'portions'ofitheicylinders Hand-23 and estabiish- I inggazconnection betweenzsaid leftehand. portions .of. cy1inders;2.2 and 23 with the exhaust portxfiii It will be clearly understoodi-nom:anexamination of Fig. '7 that .-under uchoconditionsa-the pistons -24rand 25 and, consequentlvthe rheadiframe '2 ll will move tothe left.

It should be understood that under: th'GLCGDditionsdescribedmboverotation ofthe'plate H in the counterclockwise -direction continues and, therefore, "for, :a. definite Liength :of :time the presssune.:shoe;l;8:.and thewpinfi'lxmove to the left with 'wveryzlittle:relativeqmovement. However, av certain :amount: ofzmovement of: the pressure shoe 5 8 over the grounded leorner :adjacentathe pin 57. takes place. :As the: pressure; shoe .18 moves over the rounded corner 56a, bending .the :workpiece in such ,movement: and proceeds to move. toward the side 5.8, it .is brought :well .to "the .left+hand aside ofthe shaft l5. .In moving-away from the pin 351. the :finger Eta :of the :switchsloses contact with ;the pin, thereby changing .the electric circuits.

Then the springz52:oftheswitchbecomes e fective to close :the same and to bring it into the position shown in Fig. ,16, thus .energizingthe solenoid 59 and causing ithepperative parts of the machine to he :set for :movem-ent of :the head to frame: 20 to the right.

Movement of rtheupressurezshoe.t3 to the right :along the side; 5810f the forming plate?! I proceeds similarly to the above described movement thereofalongxt-he side 56. When the-pin59 on the or forming plate is. reached, ithe same'being :at that moment above and'to the right-ofshaftlfi, the fin r 15! e agessai'd p es and, therefore, the pressure shoe 1 8 moves to 'jtheiMfteaS :the pin 59 revolves bodily around :the axistofathesshaft It.

so As the pin 59 continues its rotation, the.:finger -5laofthe:switchlosescontact with the pin 59 and the 'switch'is operated .to causerncvement of the pressure1shoe l 8 to-the right-along the side =60 of the -.plate .l I. {Fhisrmovemenms relatively so rapid and *the'shoe reaches a pin when the same is at the :upper right-hand side of theshaft IS. The finger .5.la:again comes inrcontact with a pin,- this time-the pin: .6: laion theiforming plate, and operates the switch permitting the pressure 7 shoe 18 to move Ito the left'ras thesaid pin fii revolves around the shaft-zaxis' l 5.. .:At"the end of the leftward :movement =.of thepressureshoe 1 it, the contact =between-zthe :finger 15m and the 1 m 61 :eeases, in consequenoe'wvhereof the pressure shoe i8 is moved toithe ;:;right: along theside 5E2 of the plate H, reaching the end of the forming track and completing the bending operation. Means are provided whereby the rotation of the forming plate ll ceases at this moment and the pressure shoe I8 is withdrawn from its contact position with the forming plate II. The workpiece I2 is then removed from the forming track and the working cycle is thus completed. A new piece is inserted onto the track and one end thereof is looked as described above whereupon the operation cycle may begin anew.

It should be noted that in view of the fact that sides 60 and B2 of the forming plate H are relatively short the pins 59 and GI are flattened as is shown in Fig. 6 in order to produce snapping action in the switch at those points and thus to accelerate its operation.

It will now be clear in view of the foregoing that the above described bending machine may be used for bending workpieces to various curvatures without reconstructing the machine. In order to adapt the machine for a different job it is only necessary to change the forming plate and to provide contact pins at the corners thereof. The operation of the pressure shoe l8 will remain substantially the same, and the machine may be successfully used as explained above despite the fact that the workpiece is bent to an entirely difierent curvature.

I claim:

1. In a bending machine, a forming plate having a track adapted to receive a workpiece and rotatable around a fixed axis, means for rotatin said plate, a pressure shoe, pressure means adapted in operation to urge yieldingly said shoe toward said plate, and fluid actuated means adapted to move said shoe at predetermined times during the operation cycle along the track of said forming plate to bend the workpiece.

2. In a bending machine, a forming plate hav-,

ing a periphera1 track adapted to receive a workpiece, said plate being rotatable around a fixed axis, means for rotating said forming plate, a

ressure shoe adapted to contact the workpiece on said track and to exert bending pressure thereon, and hydraulically actuated means adapted to move said shoe along said track in two directions during a single operation cycle.

3. In a bending machine, a forming plate having a. peripheral track adapted to receive a workpiece, said plate being rotatable around a fixed axis, driving means for rotating said forming plate, a pressure shoe adapted to contact the workpiece on said track and to exert bending pressure thereon, and two opposing cylinders with two hydraulically actuated pistons slidably fitted in said cylinders, respectively, and connected to said pressure shoe to move the same along said track in two directions during a single operation cycle.

4. In a bending machine, a forming plate rotatable around a fixed axis, said plate being provided with a peripheral groove adapted to receive a workpiece, means drivingly connected to said plate for rotating the same, a pressure shoe adapted to contact the workpiece in said groove and to exert bending pressure thereon, a cylinder with a fluid actuated piston operatively arranged therein and connected to said pressure shoe to exert pressure thereon and to move it toward and away from said forming plate, two opposing cylinders each having a fluid actuated piston connected to said pressure shoe for moving the same in opposite directions along said groove during a single revolution of said plate.

5. In a bending machine, a forming plate rotatable around a fixed axis, means drivingly connected to said plate for rotating the same, said plate being provided with a peripheral groove adapted to receive a workpiece, a pressure shoe adapted to contact the workpiece in said groove and to exert bending pressure thereon, a cylinder with a fluid actuated piston operatively arranged therein and connected to said pressure shoe to exert pressure thereon and to move it toward and away from said forming plate, two opposing cylinders each having a fluid actuated piston connected to said pressure shoe for moving the same during a single operation cycle in opposite directions along said groove and in the plane of rotation of said plate.

6. In a bending machine, a forming member having a track adapted to receive a workpiece, said member being rotatable around a fixed axis, means for rotating said forming member, a pressure shoe adapted to contact the workpiece on said track and to exert bending pressure thereon,

hydraulically actuated means adapted to move said shoe along said track, and electric means controlled by said forming member in its rotation and adapted to control said hydraulically actuated means.

'7. In a bending machine, a forming member rotatable around a fixed axis, means for rotatme said forming member, said member being provided with an external track adapted to receive a workpiece, a pressure shoe adapted to contact the workpiece on said track and to exert bending pressure thereon, a cylinder with a fluid actuated piston operatively arranged therein and connected to said pressure shoe to exeit pressure thereon and to move it toward and away from said forming member, a cylinder having a fluid actuated piston connected to said pressure shoe from moving the same in opposite directions along said track during a single revolution of said plate, and electric means controlled by said forming member in its rotation and adapted to control the operative pressure in said last-named cylinder.

8. In a bending machine, a forming plate rotatable around a fixed axis, means drivingly connected to said plate for rotating the same, said plate being provided with a peripheral track adapted to receive a workpiece, a pressure shoe adapted to contact the workpiece in said track and to exert bending pressure thereon, a cylinder with a fluid actuated piston operatively arranged therein and connected to said pressure shoe to exert pressure thereon and to move it toward and away from said forming plate, a cylinder having a fluid actuated piston connected to said pressure shoe for moving the same in opposite directions along said track during a single revolution of said plate, electrically actuated means adapted to control fluid pressure in said last named cylinder, and an electric switch controlled by said plate in its rotation, said switch being, in turn, adapted to control said electrically actuated means.

9. In a bending machine, a forming plate rotatable around a fixed axis. means drivingly connected to said plate for rotating the same, said plate being provided with a groove adapted to re ceive a workpiece, means for locking one end of said workpiece in said groove, a pressure shoe adapted to contact the workpiece in said groove and to follow said groove for bending said workpiece, a head adapted to carry said pressure shoe, a pressure cylinder having a fluid actuated piston connected to said head and adapted to exert pressure thereon and to move said head and said shoe spasms towardtand away from' said .grooveg and two op=-- posing cylinders 'each' lia'ving a' flu'i'd actuated pid ton connected 'itd said hea'd ifor movinglsaid pr es sure snoe along-said groove as said plate :rotates;

101' 3 In I a bending machine a forming plat rotatable aroundafixed axis, motormeans drivingly connected to said plate for 'rotati ng the same, said? plate being provide'd' with a groove having a fluid actuated piston connected; tOlSELid head: for; moving I: said pressure: shoe? along; said groovea intermittently; duringrthe; single operation cycle"as?saidvplateirotatesu,

11. In a abendingzmachinej arforinin'g i plate; ro-' tatable around a fixed axis, means drivingly con nected to: saidplaterfor'rotatingitlieisame in one predetermined direction; said plate, being pro-@- vided with a track adapted ton-receive: a work piece; means for; locking: onerend of said workpie'ceon said track, a=headmovable in2the plane of rotation of said plate along twojsubstanti'ally perpendicular paths, and-:- a pressure shoe carried by-said"head, and-adapted: to conta'ct theworkpiece "on saidrtrack and to follow 'said track.

forfbending: said workpiecer i2. In -a bendinggma'chine'; ,ar-forming plate 5 rotatable around a: fixed taxi-s; means for: rotating said plate in one predetermined direction; said plate being; provided with a groove adapted to receive a workpiece, means for locking one end of said workpiece in said groove, two opposing cylinders each having a fluid actuated piston slidable therein, a head frame actuated by said pistons and movable in the plane of said forming plate, a head carried by said head frame and movable therein transversely of the path of said head frame, and a pressure shoe carried by said head and adapted to contact the workpiece in said groove and to follow said groove for bending said workpiece.

13. In a bending machine, a base, a forming plate rotatable around an axis fixed with respect to said base and provided with a peripheral track adapted to receive a workpiece as the same is forced thereinto for bending, means for rotating said plate in one predetermined direction, means locking one end of said workpiece to said track, two opposing cylinders mounted on said base each having a slidably fitted hydraulically actuated piston, a head frame, said pistons being operatively connected to said frame for moving the same substantially in the plane of rotation of said plate, a head carried by said frame and movable therein transversely of the line of travel of said head frame, fluid actuated means carried by said head frame and adapted to move said head toward and away from said forming plate, and a pressure shoe carried by said head and adapted to contact the workpiece in said track and to follow the same for bending said workpiece.

1-1. In a bending machine, a base, a forming plate mounted on said base for rotation around a fixed axis and provided with a forming track adapted to receive a workpiece as the same is forced thereinto for bending, means for rotating said forming plate in one predetermined direction, means locking one end of said workpiece to s track, guideways provided on sai'd base adjacent said forming plate, a h'ead ff'a'me' slid able m said' guideways; two opposing cylinders mounted' on said basefea'ch havingl a hydraulically actuated piston slidablyfitted -th'er'e'in andconnected -t'o saidhead rrame forrmoving-"thesame iri said gnideways, a\ heads carried' by said frame and movabletherein?'substantiallyt perpen'dicular tosaicl guidewaysymeans adaptedito press'at 'predetermined tii'nes'sai'di headxtowardisaiddonning:

plate, and a pressure shoe carried by said hea'd and -adapte'd to contact th'e; workpiece: inl said track' and: to exert? bending: pressure thereon as saidilforming.platezrotatesi.

152: In -a bendingi machinegaaformingplate 'ro-'= tat'ablei around 'a'ifixed axis; said plate:- beingsprox-= vid'ed with aiperiplieral trackiadapted'ato receive a workpiece; nieans for; rotating saidplate, apressure/shoe adapted to contact the: workpiece in said track: and; to exert bendingt pressure" thereon, yielding: means: connected to i said ;'pres=- sure =shoei andzadapted7'ttn exert :pressure: thereon I and to move it toward and away from said-formingplate; a'cylinder havingsmfiuidactuated piston: slidably: fitted 'thereinsa'n'd; connected to said pressures; shoe: to: movet thecsame transversely of the; path intwhich: ittis' moved by; said T yielding;

means, a valve controlling: fluid cpressure": said cylinder, an solenoid; mechanically-.1" connected" to said-valve? te-actuate theisame, a switch operated by said; forming plate and: electrically connected" tozsaida solenoidxto. control the 'samecto cause at' predetermined; portions'i of": thei-"opferationi cyclem'ovem'ents'of :said pressure shoei along: saidpe ripheral track.

16 In abendingmaciiineqga forming plate 1'0.-

tatable arounda fixed axisusaid-plateibeingspro vided with as peripherals-track; adapted -to receivea workpiece;- meansfor: rotating: saidv plate;. apressure shoe adapted to contact the workpiece in said track and to exert bending pressure thereon, yielding means connected to said pressure shoe and adapted to exert pressure thereon and to move it toward'and away from said forming plate, a cylinder having a fluid actuated piston slidably fitted therein and connected to said pressure shoe to move the same transversely of the path in which it is moved by said yielding means, a valve controlling fluid pressure in said cylinder, a solenoid connected to said valve to actuate the same, a switch carried by said pressure shoe to move it toward and away from said forming plate, a cylinder having a fluid actuated piston slidably fitted therein and connected to said pressure shoe to move the same transversely of the path in which it is moved by said yielding means, a valve controlling fluid pressure in saidcylinder, a solenoid mechanically connected to said valve to actuate the same, a switch carried by said pressure shoe and electrically connected to said solenoid tocontrol the same, and a pin on said plate adapted to contact said switch and to o-perate the same when said shoe reaches a predeter, mined point along said track.

18. In a bending machine, a rotatable forming plate having a track adapted to receive a workpiece, means for rotating said plate around a fixed axis, a pressure shoe, means for maintaining said pressure shoe in pressure contact with said workpiece and to move said shoe along a straight line path toward and away from said plate, and means for producing active forces and connected to said shoe for moving the same transversely of said straight line path and along said track.

19. In a bending machine, a rotatable forming plate having a track adapted to receive a workpiece, means for rotating said plate around a fixed axis, a pressure shoe, pressure exerting means adapted to maintain said pressure shoe in pressure contact with said workpiece and to move said shoe along a straight line path toward and away from said plate, and fluid actuated means adapted to move said shoe and said pressure exerting means bodily along a path substantially perpendicular to said straight line path and along said track.

20. In a bending machine, a forming member having a curved peripheral track with changing rate of curvature and adapted to receive a workpiece to be bent, said member being rotatable around a fixed axis, means for rotating said forming member, a pressure shoe, means for maintaining said pressure shoe in pressure contact with said workpiece, and reciprocating means for exerting on said shoe a force capable of moving said shoe in either of two directions along the workpiece independently of rotation of said forming member.

21. In a bending machine, a forming member having a curved peripheral track with changing rate of curvature and adapted to receive a workpiece to be bent, said member being rotatable around a fixed axis, means for rotating said forming member, a pressure shoe, means for maintaining said pressure shoe in pressure contact with said workpiece, and means for exerting on said shoe a force capable of moving said shoe along said track independently of rotation of said forming member.

22. In a bending machine, a forming member having a curved peripheral track with changing rate of curvature and adapted to receive a workpiece to be bent, said member being rotatable around a fixed axis, means for rotating said forming member, a pressure shoe, means for maintaining said pressure shoe in pressure contact with said workpiece, and fluid actuated means for exerting on said shoe at predetermined times forces capable of moving said shoe along said workpiece independently of rotation of said forming member.

23. A bending machine according to claim 21 in which said last-named means comprises a slide connected to the shoe and opposed cylinders having fluid actuated pistons connected to said slide.

24. In a bending machine a forming member having a curved peripheral track with changing rate of curvature and adapted to receive a workpiece to be bent, said member being rotatable around a fixed axis, means for rotating said forming member, a pressure shoe, means for maintaining said pressure shoe in pressure contact with said workpiece, and means for exerting on said shoe a force capable of moving said shoe along the workpiece in a direction opposite to the direction of rotation of said workpiece and independently of the rotation of the forming member.

PAUL F. MAIZE.

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