US2325523A - Metal rolling and bending device - Google Patents

Description

July 27, 1943. B, LERMONT ETAL METAL ROLLING AND BEHD ING DEVICE Filed Feb. 8, 1943 4 Sheets-Sheet 1 INVENTORS emon? AI'MIJ N. If

*M NEYS' 4 Sheets-Sheet 2 .LiQiZ-IQ' mvENfoRs 1% Ar" .14 M. wu BY Y W ATTORN EYS B, LERMQNT ETAL Filed Feb. 8, 1943 METAL ROLLING AND BENDING DEVICE 2 \w v 2 w \T% w July 27, 1943.

"Jul 27, 1943. LERMONT mL 2,325,523

METAL ROLLING AND BENDING DEVICE Filed Feb. s, 1943 4 Sheets-Sheet 3 INVENTORs B07 Lemo 7 Arnold l1. ulf

a -WWW ATTORNEYS -July 27, 1943. B. LER'MONT EI'AL 2,325,523

METAL ROLLING AND BENDING DEVICE Filed Feb. 8, 194:5 4 Sheets-Sheet 4 INVENTORS 5::1'1 tar-m 1- 1 ATTORNEYJ Patented July 27, 1943 Basil Lermont, New York, and Arnold M. Wolf,

Brooklyn; N. Y., assignors to Cairns Corporation, Brooklyn, N. Y., a corporation. of Delaware Application February a, 1943, Serial No. 475,098 4 Claims. (01. 15354) This invention relates to devices for shaping sheet metal and relates more particularly to devices for rolling and bending sheet metal into a wide variety of curved forms having single or multiple curvatures.

A large demand exists for sheets of metal having simple'or complex curvatures for'use in the manufacture of aircraft, boats, land vehicles and the like and for apparatus that is capable of producing such sheets in a minimum amount of time and at low cost. Heretofore, metal bending devices have been sharply limited as to the types of sheets that could be produced thereby,

and moreover they are not adapted to be bper-' ated automatically to produce duplicate sheets having complex and varying curvatures. f

An object of the present invention is to provide apparatus which is capable of rolling and bending metal sheets into a wide variety of curved forms. 7

Another object of the invention is to provide apparatus that can be adjusted easily to produce a wide variety of curved metalarticles.

Another object of the invention is to provide apparatus that can be automatically controlled to produce metal sheets having complex curves and that can readily duplicate such curved sheets.

Other objects of the invention will become apparent from the following description of a typical form of apparatus embodying the present invention.

Apparatus of the type embodying the present invention is provided with three rolls-that are engageable with a sheet of metal; two of the rolls acting to advance the sheet of metal and the third being adjustable toward and away from and angularly with respect to the other two to impart varying curvatures to the sheet. Thus, by suitably adjusting the rolls, the apparatus may be caused to shape a metal sheet into cylindrical r conical forms or substantially any combination of curved forms of the same or varying radii.

More particularly, apparatus embodying the invention may be automatically controlled to vary the relationship of the rolls and to produce complex curved sheets of identical shape. By varying the automatic controls, the shape of the sheet produced may be altered, as desired, and thereafter reproduced as often as desired. Automatic control of the movement of the adjustable roll may be effected by means of cams actuated by movement of the feed rolls and, the adjustable roll so that the adjustments are always related directly to the position of the sheet being processed and the position of the adjustable roll.

For a better'understanding .oi the present invention, reference may be had to the accompany-' ing drawings in which: x 'Figure 1 is a view in side elevation of a typical form of device embody ng t e present invention; Figure 2 is a view in front elevation of the device;

Figure 3 is a top planview of the cam arrange- '-ment of the device; and

2 Figures 4 and 4a are a schematic wiring dia gram of the apparatus.

As illustrated in Figures 1 and 2, a typical form 01' rolling and bending apparatus in accordance with the present invention may include a base I0 consisting of a top II and legs I2 and I3 at oppo ite ends thereof for supporting the rolls of the bending device.

The rolling and bending mechanism proper may consist of a pair of rolls II and I5 having their axes disposed in a common vertical plane. The opposite ends of the roll l4 are joumaled in the side members I6 and I! that project upwardly and rearwardly from the top II or the base member III.

The roll I5 is mounted in suitable journal blocks I8 which are slidably mounted in vertically disposed openings Iia in the side members I6 and Il so that the spacing of the rolls I 4 and I5 may be regulated to accommodate metal sheets of varying thickness. The roll I5 may be moved relatively to the roll I I by means of screw members I9 threaded into the side plates I 6 and 11 and bearing against the undersurfaces of the journal blocks I8.

The rolls I4 and I5 serve primarily to feed a sheet of metal therebetween and to grip the sheet of metal tightly as it is fed therethrough. In order to advancethe sheet of metal, the roll I4 may be driven through a suitable train of gears including a large gear 20 fixed to the end of the roll I 4, a small gear 2| suitably supported on a shaft 22 journaled in the side member I! and having a second large gear 23 fixed thereto which meshes with a small gear 24 fixed to a shaft 25 journaled in the side member I I and having a pulley 26 mounted thereon. The pulley is driven by means of a motor 21 and a belt 28.

It will be understood that the drive gearing may be varied as may be desired in order to effect a reduction between the speed of the motor and the speed of rotation of the roll I5, and that both of the. rolls I4 and I5 may be driven by suitable gearing.

In order to bend the sheet of metal into the desired curved form, a third roll 29 is provided. The roll 23 is preferably journaled in semispherical bearing members 33 which are received in journal blocks 3! that are slidably received in elongated openings 32 in the frame members it and H. The openings 32 are inclined at-an acute angle with respect to the plane passing through the axes of the rolls M and I5 so that as the roll 29 is moved from its right hand position, as viewed in Figure 1, to-

ward its left hand position, it will move upwardly with respect to the rolls iii and i5. Preferably the axis of the roll 29 is movable in a plane passing through the axis of the roll 15.

When the roll 29 is in its right hand and lowermost position, the sheet of metal is forced against the upper surface of the roll 29 and is deflected upwardly to only a small extent, thereby imparting a curvature of relatively long radius to the sheet. As the roll '29 is moved to the left and upwardly, the sheet is deflected upwardly to a greater extent and thereby is curved more sharply or on a shorter radius. By adjusting the roll 23 toward and from the pair of rolls i i and t5, the curvature of the sheet can be correspondingly varied. v

The adjustment described above will cause the sheet to be curved on the same radius from edge to edge. In order to vary the radius of curvature of the sheet from edge to edge, the ends of the roll 29 may be displaced unequal distances from the rolls i4! and Ed by adjusting the slide blocks at opposite ends of the roll 29 along the slots, The semi-spherical bearings 33 prevent binding of the ends of the roll in the slide blocks 32.

While the adjustment described above can be accomplished manually, itis preferred to provide an automatic control system for regulating the position and movements of the roll 29 so that duplicate sheets of varying curvature can be produced automatically.

The apparatus for regulating the position of the roll 29, as illustrated, may consist of two reversible motors 33 and 3d supported at opposite ends of the table H. Each of the motors 33 and 34 acts to adjust one end of the roll 29. Inasmuch as the motors and associated driving mechanism are the same for each end of the device, only one of the motors and driving mechanisms will be described herein.

The motor 33 is provided with a gear 35 which meshes with and drives a gear 36 that is supported on a shaft 31 having a bevel pinion. 38 at its opposite end. The shaft 31 is journaled in a suitable bearing 39 on a table 40 disposed in front of the rolling device. The table 40 is provided with suitable supporting legs 4| and is anchored to the base ID of the rolling device in any suitable way.

The bevel pinion 38 meshes with the bevel gear 42 that is mounted on a shaft 43 substantially coaxial with the axis of the slot 32. The shaft 43 is journaled in suitable bearings 44 supported on the table 40. The shaft 43 is coupled by a universaljoint 45 to a threaded shaft 46 that is threaded into a sleeve 41 carried by a plunger 48 that is connected to the journal block 3|. Thus upon rotation of the shaft 43 by the motor 33, the threaded shaft 46 is screwed into or out of the sleeve 41 advancing or retracting it, the journal block 3| and the left hand end of the roll 29.

The right hand end of the roll 29 is adjustable in the same manner by means of the motor 34 and associated gearing of the type described above.

While the motors may be controlled manually in order t adjust the position and angular relationship between the pair of rolls and the adjustable roll, such adjustment preferably is effected by means of a cam mechanism by means and direction of operation of the motors 33 and 34. The cam members 53 and 58 may consist of tubular elements slidably mounted upon a rod 55 extending transversely of the table (it and fixed to the center pair of legs fill-M of the table. Each of the cam members 53 and 56 is provided with cam lobes 53a, 53b and 54a, 56b at their opposite ends and have downwardly projecting rollers 53c and 5&0 which engage in the cams 5i! .and ti, respectively. Upon endwise shifting of the cams 53 and Hi, the cam members 53 and 66 will be shifted endwise as the rollers 53c and 560 are deflected by undulations in the cams 5t and 59.

The cam, members 53 and 56 are disposed beneath a pair of switch boxes 53 and 5'? which control the motors 33 and 34, respectively. Each switch box contains a pair of double pole, double throw switches to be described later. One switch in each box 53 or 51 causes rotation of the motors 33 and 3G in a clockwise direction, while the other switches cause the motors 33 and 34 to rotate in a counterclockwise direction. The switches in box 53 are normally biased open and are actuated into one position by movement of the follower rollers'56a or 56b onto the top of one of the cam lobes 53a or 53b. The switches in switch box 5! are actuated by the rollers 51a or 51b engaging the cam lobes 54a,.

56b or on the recess therebetween on the cam member 53 into another position by movement into the recesses between the lobes. Thus, the direction of rotation of the motors 33 and 34 is dependent upon the position'of the cam members 53 and 5d and the extent of displacement of each end of the roll 29 is dependent upon the extent of operation of the motors 33 and 34. In order to effect accurate control of the position of the roll 29, stoppage of the motors 33 or 34 is controlled entirely by the position of the roll 29 as will now be described.

Each of the switch boxes as and 57 is, slidjacent its midportion at the rear of the table' 40. This lever may include a supporting shaft 63 that extends from adjacent the switch box 56 to adjacent the left hand end of the table 40 as viewed in Figure 2. The upper end of the lever 82 is connected by a link 84 to the slide block 8|. I

The switch box 81 is connected by a similar linkage to the slide block 3| that supports the right hand end of the shaft and is responsive to its movement.

The travel of the earns 58 and is related to the movement of the sheet being processed In order to permit duplication of curvatures in successive sheets. Endwise movement of the cams 88 and BI is accomplished by means of a cable 85 that is wound around a drum 88 on the end of the roll I4. The cable 85 is looped over suitable pulleys 81 and ,88 and one flight thereof is connected to the cams 88 and BI so that during rotation of the roll I4 the cams 58 and 5I are moved longitudinally.

The motors 21, 33 and 34 may be provided with plugging switches 88, 18 and H which cause the motors to stop immediately upon opening of any of the control switches. Such switches operate to reverse flowof current in the field of the motor, bringing the motor to a stop. Upon stoppage of the motor a relay cuts off the current supply so that reverse rotation of the motor will not take place. With this arrangement, extremely close control of the position of the roller 28 and operation of the motor 21 may be obtained.

In order to prevent accidental damage to the device, normally open limit switches 12, 13 may be mounted on each of the side members I8 and I1. These switches are connected in the motor circuits and when opened, deenergize the motors. The switches 12 and 18 may be opened by means of a contact ring 14 on each sleeve 41. When the contact ring 14 comes in engagement with a limit switch 12 or 13 at either end of its path of travel, the motor circuit is opened and the motor stops. If desired, limit switches H4, H5 may be used to stop the motor 21 to prevent overrun of the cams 58 and BI.

As illustrated diagrammatically in Figures 4 and 4a, the control circuit for the apparatus may be arranged to provide both manual and automatic control for-the motors 21,- 33 and 34, which are shown as constant speed motors.

The circuit includes a master control switch 8|, having a contact 8Ia connected by a conductor 82 to the power line 88a of a three phase power supply. The switch blade 8Ib is connected by a conductor 83 to three contacts 84a, 84b and 840 of a manual control switch 84 having manually operated switch blades 88d, 84c and 88). The switch 84 is provided further with contacts 849, 84h and ML The contacts 84a and 84g and blade 84d form a normally open forward switch. The contacts 84b and 84h, and blade 84e form a normally open reverse switch and the contacts 84c, 841 and blade 84) form a stop switch, which is normally closed.

When the blade 8411 is depressed and the master switch BI is closed, a circuit is completed from the power supply line 88a, through conductor 82, contact 8Ia, blade 8Ib, conductor 83, contact 83a, blade 84d, contact 84g, conductor 85, solenoid 88a of relay 88, conductor 81, contact 88a of relay 88, blade 88b, contact 880, conductor 88, to conductor 880 of the power supply lines. Passage of current through the solenoid 88a of relay 88 closes all of the normally open contacts thereof. Actuation of this relay completes a circuit for starting the motor 21 in a forward direction, as follows: Current passes from conductor 880 through conductors 88, 8| to the solenoid 88a of the pluggin switch 88, then through conductor 92 to the contacts 881: of relay 88 and the contact 83a of relay 83. Inasmuch as the contact 88b is connected to contact 880 by the now closed contact blade 88d, connection further is made to conductors 84, 85 to contact 88a of relay 98 through blade 88b, to contact 880, then to contact 88d, blade 88c, contact 88), conductor 91 to contact 88c, blade 88! and contact 869, conductor 91a to the overload protector relay 88, conductor 98, contact I88a, blade I88b and contact I88c of relay I88, conductor I8I through solenoid I82a of relay I82 to the main conductor 88a, thereby actuating the relay I82 which connects the motor 21 to the lines 88a, 88b and 880 through the relay switches I82d, I82e and I82f and conductors I84, I85 and I88. At the same time the reversing shoe 88b of the plugging switch 89is lifted out of contact with the motor shaft.

The motor 21 will continue to operate until stoppage is desired after the "forward switch 84a; 84d and 849 is open inasmuch as the stop" switch 88c, 84) and 84$ forms a holding circuit for the solenoid 88a, as follows, main conductor 88a, switch 8I, conductor 83, contact 840, blade 84!. contact 841', conductor I84, conductor I85, contact 88h, blade 8, contact 88f, solenoid 88a, conductor 81, contacts 88a and 880, conductor 89 to main conductor 880. The solenoid 88a will remain energized until the stop switch is opened, thereby breaking the circuit and doomergizing solenoid I82a of the forward motor control relay I82.

For reverse operation of motor 21, a similar circuit is provided. When the main control switch BI is closed, a circuit is completed from main conductor 88a through the switch 8I. Upon actuation of "reverse switch 84b, Ne and 84h, current flows from contact 84h, through conductor I81 to the solenoid 83b of relay 83, conductor I88, contact I89a of relay I88, contact I090, conductor II8, conductor 88 to-main conductor 88c, thereby closing relay 88. a circuit is completed through the solenoid 68a to pick up the shoe 88b of plugging switch 89 and energize the solenoid I88d of the relay I88 to energize the motor 21 for reverse operation. This circuit is as follows from mains conductor 88c, conductors 88, 8I, solenoid 89a, conductor 82, contact 93a, contact 83d, conductor 95, contact 88a, blade 98b, contacts 88c, 88d, blade 88c, contact 98f, conductor 81, contact 93f, contact 93h, conductor III, overload protector relay IIZ, conductor II3, contacts I82b, contact I820, conductor II3a, solenoid I88d to mains conductor 88a. The motor 21 is thus connected to the mains 88a, 88b and 880 through the relay switches I88e, I88) and I88g and the lines I84, I and I88, with the connections reversed with respect to the connection through the relay I82.

The stop switch 840, 84) and 842' forms a holding circuit similar to that described above for reverse rotation of the motor 21.

If desired, the apparatus may be provided with limit switches H4 and H5 for controlling the movement of the rolls I4 and I5, the motor 21 and the movement of the cams 58 and 5i.

The limit switches H4 and H5 are double contact switches that are normally open and may be moved to closed positions by cam lobes (not shown) on the cams 58, 5|, or by engagement with the cams 58, 5|, at opposite ends of their path of travel. The connections of the switch I I4 are as follows: conductors 88c, 88, H8 to con- When relay 93 closes,-

. I21 and to mains conductor 80c.

switch blade I24a engages contact I24b in auto-- tacts H411 and H51), contact II4b, conductor II1, solenoid I09d of relay I09, conductor II8 to com tact 84c, switch 8I and to mains conductor 80a. When the switch H4 i opened, therefore, the relay I09 is deenergized closing the circuit between contacts I09a and I09c and completing the circuit through the solenoid 93b of reverse relay 93. Opening the circuit between contacts I09a and I090 by closing switch H4 deenergizes the solenoid 93b and opens the circuit to motor control relay I00.

Similarly, the contact 50 of forward limit switch H is connected by conductor H9 through solenoid 88d of forward relay 88 to conductor H8 and contact 840 of the stop switch. Therefore, when the switch H5 is closed, the solenoid 88d is deenergized, opening the circuits through the relay 86 and stopping the motor 21.

In order to bring the motor 21 to an almost immediate stop, the plugging switch 69 is proto the solenoids I00d and I02a by the conductors I2I and I22. Inasmuch as the opposite ends of the solenoids I001; and I02a are connected to the mains conductor 60a, a circuit will be completed through one of the solenoids when the blade 09g is moved by rotation of the motor 21.

This arrangement is such that the motor is reversed automatically and brought to a standstill when the blade 69g engages and then disengages the sets of contacts 69c, 69 and 69c, 69d.

The controls for the motors 33 and 34 may be either manually operated or automatic. automatic control is obtained by means of the cam controlled switches in the switch boxes 56 and 51 as will be described now. The switch for controlling the motor 33 includes two double throw blades 56b and 560, blade 56b cooperating with four contacts 56d, 56c, 56) and 569. Contact 56d is connected by conductor I23 through a lag switch LS to the blade I24a of a three position switch I24 that is used to set the device for hand or automatic operation. The blade I240. also is connected by conductors I25 and 82 to mains conductor 60a. Contact 56e is connected to conductor I26, solenoid 96g of relay 96 and then by conductor I21 to mains conductor 80c, thereby actuating relay 96 when ner as contacts 56d and 56e.

Thecontacts 56g and 5610 are connected by conductor I28 to one side of the solenoid I29a of the relay I29, then to conductor I30 to contact I24b of the switch I24. The other side of the solenoid I29a is connected to the conductor Thus when the The matic position, the solenoid M911 is energized conductor ductor I3I to upper contact I29b and when the relay I29 is actuated to closed position a circuit is completed from contact I290 through conductor I32, solenoid I33a of relay I33, conductor I34, contact I35a of normally closed limit switch I35, contact I351) and conductor I36 and 90 to mains conductor;- 80c. As a result, when the contacts 56, and 56g are closed, the solenoid I33a is energized, closing all of the contacts thereor'. When this relay is closed, a circuit is completed from mains conductor 800 through conductors 82, I31, contacts I 33b, I330, conductor I38, relay solenoid I39a, conductor I40, contact I4Ia of reversing relay I M, contact I4Ib, I42, overload protector relay I43, conductor I44 to mains conductor 80c thereby closing motor control relay I39 for motor 33 and starting the motor 33 in a forward direction. The solenoid 10a of plugging switch 10 is simultaneously energized as follows: mains 80a, conductor I21, contacts I33d, and I 33c, conductor I 45, solenoid 10a, conductors I46, 90 to' mains 80c. I

The contacts 56k and 567' are used for actu ating the motor 33 in a reverse direction as follows: Contact 561:: is connected to conductor I28, and to the contact I24b of switch I24 as described above'so that power is supplied from con- .ductor 80a to contact 56k. When the switchblade 56c closes contacts 567' and 56k, power flows from 569' through conductor I48 to contact I29d, contact I 29e, conductor I49 to solenoid I50a of reversing relay I50, conductor I58, normally closed limit stop switch I52, conductors I38 and 90 to mains c, thereby closing relay I50. When relay I50 closes, the following connections are made: mains 80a, conductor I31, contacts I501), I500 of relay I50, conductor I45, plugging switch solenoid 10a, conductors I46, to mains 80c thereby energizing the solenoid 10a. Si-

multaneously, the motor 33 is started in reverse I as follows: mains 80a, conductor I31, contacts I50d and I506, conductor I54, solenoid I4Ic of reversing relay I4I, conductor I56, closed contacts I39?) and I390 of, forward relay I39, overload protector relay I51, conductor I44 to mains 80c thereby actuating relay I55 and connecting the motor 33 to the mains.

In order to bring the motor 33 to a quick stop,

- the contacts 10b, 10c, 10d and 10e of the plugging switch 10 are used in conjunction with the motor controlled shiftable contactor 10f. The contacts 10d and 10a are connected by a conductor I58 to the mainsv conductor 80a. Contact 1022 is connected by conductor I 59 to solenoid I39a, conductor I40, contacts I4Ia, I4Ib, conductor I42, overload protection relay I43 and conductor I44 tomains conductor 800. Similarly, contact is' connected by conductor I6I, to solenoid I4Ic, conductor I56, contacts I39b and I990 of motor reverse relay I39, overload protector relay I51 and conductor I44 to mains conductor 800. The operation of plugging switch 10, therefore, is the same as that of the plugging switch 69, described above.

The operation of the motor 34 and the circuits therefor, for the cooperating plugging switch H and the motor control switches 51 are identical with those described for motor 33 with the exception that a different set of relays I65 and I66 are used for controlling the solenoid of the plugging switch H and the forward and reverse motor relays I61 and I68.

If desired, the automatic controls for the motors 33 and 34 need not be used and manual control of these motors obtained. In order to control the motors 33 and 34, additional forward and reverse switches are provided. Inasmuch as these manually actuated switches and their circuits are the same, only one set will be described, as used with the motor 33.

The "forward switch I and the "reverse" switch I" each has a contact I10a and "la connected to contact l24c of the selector switch I24 and thus may be connected to the mains 90a through switch I24. switch I10 is connected by conductor I12 to contact I29c and to the conductor I32, the solenoid I33a of relay I33, conductor I34, limit switch I35 and to mains 80c, thereby closing the forward control relay I33 and energizing the plugging switch solenoid 10a and the forward power relay I39 as described above. The relay I29 is not closed inasmuch as the switch I24 is not in automatic position and the connection to contact I29e is, therefore, an open circuit.

Similarly, the contact I1Ib is connected by conductor I to conductor I49, solenoid I50a of Contact I10b of forward cams 50,- 5I to starting position. This circuit 7 includes a switch I90 having a blade I90a connected to the switch I24 and having a contact I905 connected through conductor I9I to contact 88c of relay 88. Opposite contact 8811s connected lights, to indicate the condition of the system.

Such signalling lamps are illustrated in Figure 4, but they will not be described as they are not necessary to effective functioning of the system and apparatus.

In operation, earns 50 and 5I of suitable contour are connected to the cable 65, the sheet is threaded between the rolls I4 and I5 and the roll 29 is adjusted into the desired position. The motor 21 is then started by closing switches 8I and contacts 84a and 84g and the cams 50 and 5I begin to move lengthwise of the cam table 52.

With the switch I24 in automatic position the undulations or offset portions of the cams 50 and 5| deflect the cam member 53 and/or 54 to actuate the switches in the switch boxes 56 and/or 51 to cause the motors 33 and 34 to operate to advance or retract the roll 29. As the roller 29 moves, the linkage system between the slide blocks 32 and the switch boxes 56 and 51 are'actuated to move the switch boxes relatively to the cam members 53 or 54. Depending upon the extent of the displacement ofthe cam members 53 and 54 by the cams 50 and 5 I, the motors 33 and 34 will continue to .operate until all of the switches in the switch boxes 56 and 51 are open, thereby discontinuing operation of the motors 33 and 34. If the cam members 53 or 54 are displaced to different extents, the motors 33 and 34 will operate for different lengths of time and the roller 29 may assume an angular position with respect to the rolls I4 and I5, thereby imparting a conical shape to the sheet of metal. Similarly, if the cam members 53 and 54 are displaced in the opposite direction by the cams 50 and 5I, the motors 33 and 34 will be driven to displace the roller 29 toward the rollers I4 and I5, thereby imparting a sharper curvature or bend to the sheet undergoing treatment.

The limit switches cooperating with each of the motors 21, 33 and 34 prevent motion of the rolls beyond predetermined limits.

The lag switch LS is used to permit operation of the motors 33and 34 for a large shift of the roller 29 relatively to the rolls I4 and I5 by momentarily stopping the motor 21 when the dis placement of the cam members 53 and/or 54 is sufficient to close the upper contacts of the switches 55 and 51 as viewed in Figure 4 by throwing out the relay 96 and deen'ergizing the power control relays I00 and I02 for the motor 21. This condition remains until the switches 56 and 51 open and the motor 21 is energized again.

From the foregoing description, it will be clear that a device has been provided by means of which controlled bending of sheets of metal may be accomplished easily, that the curvature of the sheet of metal may be varied widely, that complex curvatures may be imparted to the sheet from end to end and from edge to edge under' close and accurate control so that individual or duplicate sheets of widely varying shape may be readily produced.

While the preferred form of the device is disclosed herein, it will be understood that the device may be modified in a great many of its details such as, for example, in the arrangement of the specific driving mechanism for the rolls, in the mechanism for adjusting the position of the adjustable roll, and in the contour, size and shape of the cams, without departing from the invention. Therefore, the form of the invention disclosed herein should be considered as illustrative and not as limiting the scope of the following claims.

We claim:

1 A metal bending device comprising a pair of parallel driven rolls for advancing a sheet of metal, cam means movable in response to rotation of said rolls, a third roll adjacent to said pair of rolls, a means at and for moving each end of said third roll selectively toward and away from said pair of rolls to vary the spacing and angular relationship between said third roll and said pair of rolls, a separate electric motor for actuating each of said means, switch means actuated by movement of said cams, and electrical connections between said switch means and said motor for moving said'third roll in response to actuation of said switches by said cams.

2. The device set forth in claim 1 comprising means for supporting said switches for movement relatively to said cams, and means mechanically connecting said switches to said third roll to displace said switches relatively to said cams in proportion to the movement of said third roll.

3. A metal bending device comprising a pair of motor driven rolls for advancing a sheet of metal, a third shiftable roll, a pair of reversible electric motors, means connecting each of said motors toa diiferent end of said third roll to shift the latter toward and away from said pair of rolls and angularly with respect thereto, switch means electrically connected to each of said motors for actuating said motors selectively in a forward and a reverse direction to advance and retract the ends of the third roll selectively, and cam means movable in response to rotation of said pair of rollsfor actuating said switch means to adjust the third roll relatively to said pair of rolls.

4. A metal bending device comprising a pair of rolls for advancing a sheet-of metal, a reversible electric motor for actuating at least one of said rolls, a third roll shiftable toward and away from said pair of rolls, 9. second reversible electric motor for shifting one end of said third roll, a third reversible electric motor for shifting the other end of said third roll, a first switch box mechanically connected to the end of said third roll shiited by said second motor and shiftable in response to shifting movement of said third roll, a second shiftable switch box connected to and shiftable with the end of the third roll shifted by said third motor, a pair of switches in said first switch box, one of said switches having contacts electrically connected to said first motor for stopping the latter when closed and other contacts electrically connected to thesecond motor to drive the motor in forward direction, when closed, the other switch having contacts electrically connected to said first motor for stopping said first motor when closed, and other contact for causing said second motor to operate in reverse, when closed, switches in said second switch box, connected similarly to said first motor and said third motor, movable switch actuating cams associated with said first and second switch boxes to control the operation of said motors, and cam means movable in response to movement of said pair of rolls for moving said switch actuating cams.

- BASIL LERMQNT.

ARNOLD M. WOLF.

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