US3805576A

US3805576A - High speed multi-bending machine

Info

Publication number: US3805576A
Application number: US00281635A
Authority: US
Inventors: E Brauer
Original assignee: Cyril Bath Co
Current assignee: Cyril Bath Co
Priority date: 1972-08-18
Filing date: 1972-08-18
Publication date: 1974-04-23
Anticipated expiration: 1991-04-23

Abstract

A machine for forming a series of bends in a rectilinear workpiece having a formed cross-section and of predetermined length where the bends are formed at predetermined locations, at high speed, and without the aid of a machine operator. The machine contains means for positioning the workpiece, means for automatically placing a pair of movable bending dies in operative relation to first positions near the ends of the workpiece, means for operating the dies to form a first pair of bends in the workpiece, means for automatically placing the bending dies in operative relation to second positions further toward the center of the workpiece, means for operating the dies to form a second pair of bends in the workpiece, and means for discharging the workpiece and returning the bending dies to a starting position.

Description

United States Patent lBrauer HIGH SPEED MULTI-BENDING MACHINE [75] Inventor: E. Henry Brauer, Cleveland, Ohio [73] Assignee: The Cyril Bath Company, Solon,

Ohio

[22 Filed: Aug. 18, 1972 211 Appl. No.: 281,635

11] 3,805,576 [451 Apr. 23, 1974 Primary ExaminerLowell A. Larson Attorney, Agent, or Firm-Alan N. McCartney [57] ABSTRACT A machine for forming a series ofbends in a rectilinear workpiece having a formed cross-section and of predetermined length where the bends are formed at predetermined locations, at high speed, and without the aid of a machine operator. The machine contains means for positioning the workpiece, means for automatically placing a pair of movable bending dies in opera'tive relation to first positions near the ends of the workpiece, means for operating the dies to form a first pair of bends in the workpiece, means for automatically placing the bending dies in operative relation to second positions further toward the center of the workpiece, means for operating the dies to form a second pair of bends in the workpiece, and means for discharging the workpiece and returning the bending dies to a startingposition.

7 Claims, '28 Drawing Figures PATENTEDAFR 23 m4 SHEET [11 [1F 10 PATENTEDAPRZB 1914 3.805576 SHEET 02 0F 10 WJUM ATENTED APR 2 3 i974 SHEET 0M 0F 10 MTENTEDAPR 23 I974 sum 08 HF 1o PATENTED APR 2 3 I974 SHEET [19 [1F 10 WNGE MNGE 1 HIGH SPEED MULfII-BENDING MACHINE BACKGROUND or THE INVENTION forms the workpiece tangentially about the anvil die;

for-this reason, these machines are known-as tangent benders.

It is already'known to manually place a workpiece in a tangent bending machine and cause co-operating dies to move into operative position there against and form a bend in the workpiece. There are also machines wherein after the first bend is formed the workpiece may be moved in the machine and a second bend formed. These machines may take the form of releasable bending dies that permit the workpiece to be manually re-positioned with respect to the die or the form where the dies are mounted on a movable carriage that traverses the length of the workpiece for performing bending operations therealong. In all of these machines, an operator is required to be present to load the workpiece into the machine, position the bending dies at the first bending station, energize the bending dies, release the dies, re-position the workpiece, etc. to unloading the machine. This.situation is acceptable where a few pieces are bent; however, where large volume production is involved, the loading, unloading, and manual positioning of the bending dies reduces output while the continual presence of the operator raises manufacturing costs.

This invention comprises a tangent bending machine constructed such that virtually all the steps are performed automatically and rapidly. The machine con tains means for loading a workpiece ontoa work surface and means for forming a series of bends on the workpiece automatically, at high speed, and without the aid of an operator, except .to discharge. the finished product. Bending dies are mounted on. movable'car riages that traverse along; the workpiece and perform a series of bending operations according to a preset sequence set in the carriage moving means and in'the bending die moving means prior to. receiving the work'- piece in the machine. The operator has only to insure that the workpiece is set on the work surface; thereafter, all bending operations are performed accurately and at high speed, thus increasing manufacturing rate and reducing costs.

SUMMARY OF THE-INVENTION A high speed machine for bending a rectilinear metal workpiece having a constant or formed section into a variety of configurations, such as into window frames and door frames for trailers and other camping vehi-- cles. The machine comprises a frame that includes means for positioning the workpiece on a work surface, means for automatically placing a pair of movable bending dies in operative relation to first positions near' the'ends of the workpiece, means for operating said dies to form a first pair of bends in the workpiece, means for automatically placing the bending dies in operative relation'to second positions further toward the center of the workpiece, means for operating the dies to form a second pair of bends in the workpiece, and means for discharging the workpiece and returning the bending dies to a starting position.

The main object of this invention is a high speed machine for forming one or more bends in a rectilinear metal workpiece. Other objects include a machine for bending metal. workpieces into a variety of different bends, and'different planes, especially long workpieces; a bending machine in which the feed stock may be easily loaded and unloaded; and a bending machine which is capable of automatic and semi-automatic control.

DESCRIPTION OF THE DRAWINGS FIG. 5 is a left side view of the left carriage taken along the lines 5-5 in FIG. 4, .showing a workpiece clamped in the carriage.

FIG/6 is a partialsectiorial view through one of the carriages taken along thelines 6-6 in FIG. 4.

FIG. 7 is a partial sectional view taken through the carriage drive screw along the lines 7-7 in FIG. 4.

FIG. 8 is a sectional view of a portion of the carriage taken along the lines 8-8 in FIG. 5.

FIG. 9 is a sectional view of part of the carriage taken along the lines 9-9 in FIG. 5.

FIG. 10 is a sectional view of part of thecarriage taken along the lines 10-10 in FIG. 5.

FIG'.'11 is a partial sectional view of the carriage taken along the'lines 11-11 in FIG. 6.

FIG. 12 is'a sectional view of part of the carriage taken along the lines 12-12 in FIG. 4.

FIG. 13 is a top view of one of the carriages showing one stage of the bending operation. I

FIG. 14 is a portion ofthe top view of the carriage of FIG. 13, showing a subsequent stage ,of the bending operation. I

FIG. 15 is a front view, partly broken away, of. the power. means forthe carriage main drive screw taken along the lines 15-15 in FIG. 3.

FIG. 16 is a sectional view of the carriage main drive power transfer mechanism taken along the lines 16-16 in FIG. 15.

FIG. 17 is a sectional view of the bending machine taken along the lines 17-17 in FIG. 2.

FIG. 18 is a partial view of the bending machine taken along the lines 18-18 in FIG. 17.

FIG. 19 is a sectional view of part of the center clamp means taken along the lines 19-19 in FIG. 18.

FIG. 20' is a partial front view of the center support for the various shafts and guide rails taken along the lines 20-20 in FIG. 17.

FIG. 21 is a sectional view of the bending machine taken along the lines 21-21 in FIG. 2.

FIG. 22 is a partial view of the bending machine taken along the lines 22-22 in FIG. 21.

FIG. 23 is a partial sectional view of the bending machine taken along the lines 23-23 in FIG. 21.

FIG. 24 is a partial sectional view of the bending machine taken along the lines 24-24 in FIG. 21.

FIG. 25 is a partial view of the bending machine taken along the lines 25-25 in FIG. 5.

FIG. 26 is a partial sectional view of one of the carriages taken along the lines 26-26 in FIG. 5.

FIG. 27 is a partial view of one of the carriages taken along the lines 27-27 in FIG. 26.

FIG. 28 is a partial view of the bending machine taken along the lines 28-28 in FIG. 26.

DESCRIPTION OF THE PREFERRED EMBODIMENT Turning now to the drawings where like elements are identified with like numerals throughout the twentyeight figures, the over-all outline of one embodiment of the bending machine of this invention is shown in FIGS. 1 and 2. It comprises a frame, generally indicated at 1 that comprises a front wall 3 and a spaced apart parallel rear wall 5, that are held assembled in a fixed geometry by a welded cross plate 7. A horizontal working surface 9 is formed on top of frame 1 by a channel '11, that spans substantially the entire width of frame 1, by cross beams 13 that extend horizontally forward in cantilever fashion from vertical stanchions 15, located to the rear of frame 1, to above rear wall 5, and by the

top surfaces

16a and 16b of traversable carriages that will be described in more detail later. Mounted on top of channel 11 is a beveled strip 17 which supports a bent workpiece during subsequent bending operations.

Along the upper edge of front plate 3 and rear plate is a track 19 that spans the width of frame 1 and slidingly receives thereon means 20 for automatically placing a pair of movable bending dies in operative relation to first positions near the ends of the workpiece. As shown here, means 20 comprises a pair of die-carrying

carriages

21a and 21b for movement along the single path defined by track 19.

Carriages 21a and 21b are independently propelled along track 19 by means 22 for automatically placing the bending dies in operative relation to second positions further toward the center of the workpiece that comprises

opposed drive screws

23a and 23b that are rotatably mounted on cross plate 7, each of which is mounted in one-half the width of frame 1.

Drive screws

23a and 23b are powered at their respective outboard ends by a variable speed power means 25a and 25b. Drive screw 23a propels carriage 21a through complimental reception thereof with a threaded nut 27 fixed to the carriage. Power means 25a comprises a motor 29 and gear reducer 31 combination that is engaged to drive screw 23a through a conventional dual pulley wheel drive belt arrangement 33. Power means 250 is housed in a dust cover 35, that is located near the outer end of frame 1. Means 22 may also comprise other recognized drive mechanisms such as cylinder and piston drive, i.e., a fixed cylinder having a reciprocally mounted piston rod therein that is fastened to the carriage. Other operable drives include a rack and pinion, i.e., a mounted rack actuated by a driven pinion, etc.

ship with track 19 through bushing pads 39 that reduce friction there between during movement of the carriage. A main carriage support plate 41, offset at 42, spans track 19 and extends both forward of frame 1 and vertical to work surface 9 and forms the support to which most of the carriage components are mounted. A flat top plate 40 is mounted on the top of main carriage support plate 41 containing top surface 16a that forms a part of work surface 9. A rear wall plate 46 spans the back side of carriage 21a parallel to and above rear wall 5.

An anvil die 43 is pivotally mounted on main carriage support plate 41 on a vertical pivot shaft 45 that is in turn mounted in bearings 47 attached to plate 41. Anvil die 43 has offsetcurvilinear (preferably cylindrical) faces 42a and 42b formed by a lobe-shaped work surface 49 in elevational alignment with work surface 9. Die 43 is made up of a plurality of disks; shown in FIG. 6 are three disks, a hold-down disk 44a, a web receiving disk 44b, and a spacer disk 440. A recess 51 is formed between

disks

44a and 44b at a level, controlled by spacer disk 44c, that matches the height above work surface 9 of the one or more webs or flanges of the workpiece that are to be on the inside of the bend. Thus, work surface 49 is in alignment with work surface 9 and is adapted to receive the workpiece in a predetermined manner. Recess 51 is only formed on one side of die 43, in offset curvilinear face 42b. Thus, rotation of die 43 will cause the workpiece to be expelled from recess 51 thereby freeing carriage 23 for subsequent movement to another bending location. I

Work surface 49 and offset curvilinear face 42b of anvil die 43 define a bending surface about which the metal workpiece is bent in the horizontal plane. As can best be seen in FIGS. 13 and 14, anvil die 43 is rotated until work surface 49 and the enclosed recess 51 engage one or more flangesof the workpiece. Upon completion of the bending operation, anvil die 43 is rotated in the direction of the arrow so that work surface 49 is moved out of contact with the flange of the workpiece, thus expelling the piece from anvil die 43.

Spaced from anvil die 43 on the opposite side of the workpiece is retractable clamp 55. Clamp 55 is slidingly mounted on carriage 21a by complimental engagement with a rail 57 that is mounted atop support plate 41. Clamp 55 comprises a clamping jaw 59 that contains a recess 61 for receiving a workpiece in a predetermined manner, a clamp jaw slide block 63 that is in complimental sliding engagement with rail 57, and a reciprocating first power means 65 that is anchored to support plate 41 through a threaded connector 67. First power means 65 comprises a hydraulic cylinder 69 cimplimentally engaged to rail 57 and anchored to connector 67, whose piston rod 71 is connected to sliding block 63. As can be seen in FIGS. 13 and 14, upon energization of first power means 65, clamp 55 contacts the workpiece such that clamp jaw 59 receives one or more of the workpieces webs or flanges in recess 61 and thereafter presses the workpiece tangentially against anvil die 43 and into recess 51. The contact point of the workpiece with clamp 55 and anvil die 43 is ahead of the wiping die so that bending is not interfered with by clamp 55.

A gate 73 is pivotedly supported slightly offset (FIGS. 9 and 10) on carriage 21 by pivot shaft 45, support block 76, and offset

ears

77a and 77b and bushings 79, for curvilinear movement through a horizontal are about shaft 45 and has a wiping die 75 mounted thereon for receiving and bending the workpiece about anvil die 43 in a horizontal plane.

Wiping die 75 slidingly mounted on edge 73 by complimental engagement with a rail 81 that is mounted atop gate 73, comprises a die jaw 83 made of hardened metal that contains a recess 85 similar to and aligned with recess 61 for receiving the workpiece in a predetermined manner, a jaw slide block 87 that is in complimental sliding engagement with rail 81 and a reciprocating second power means 89 that is anchored to gate 73 through a threaded connector 91. Second power means 89 comprises a hydraulic cylinder 93 pivotally mounted to a base 95, also slidingly engaged to rail 81, whose piston rod 97 is connected to slide block 87 by a multiplelink connection 99. Upon energization of second power means 89, die jaw 83 advances toward anvil die 43 and slidingly clasps the workpiece there between upon full, rigid extension of linkage 99. Optionally, clamp 55 presses againstthe workpiece and abuts the workpiece against anvil die 43. Thereafter, gate 73 is swung about anvil die 43 to bend the workpiece about said die. During this swinging motion, wiping die jaw 83 slides along the workpiece and deforms it about anvil die 43 to form the bend. Because the exposed flanges andwebs of the workpiece are retained in recessesSl and 61 during this bending meovement, there is no buckling or folding of the metal.

Gate 73 is caused tomove about anvil die 43 by a means 101 for operating the dies to form bends in the workpiece that comprises a hydraulic cylinder 103 pivotedly mounted on

parallel wing plates

104a and 104b in spaced relation to carriage 21 having its piston rod l05 connect'ed to gate 73 through an eccentric arm and adjustable linkage 107. Retraction of piston rod 105 into hydraulic cylinder 103 causes pivotal motion of gate 73 about pivot shaft 45.

As shown in FIG. 8, a protractor face 100 is on pivot shaft 45 between top plate 40 and gate 73 so that the operator may visually check the degree of bend given the workpiece bywiping die 75 andadjust third power means 101 to increase or decrease the amount of bend. I Y

Following completion of the bending operation, which may take the form of overbending to compensate fotfspring-back of the particular metal workpiece (shown in FIG. 14 in dotted lines), wiping die 75 is retracted from the workpiece and gate 73 is swung back to its original position adjacent clamp 55. Also, anvil die 43 is rotated out of overlapping engagement with the exposed flange or flanges of the workpiece by release means 109 that, according to the embodiment shown in FIGS. 6 and 11, comprises a pinion 111 on pivot shaft 45 that is in complimental engagement with a rack 113 that is connected to a reciprocating piston rod and hydraulic cylinder 115. Another embodiment of means 109 may include a swing arm connecting piston rod and cylinder 115 to shaft 45 to move it laterally through an arc and out of contact with the workpiece. Carriage 21a is programmed to move along track 19 by energizing variable speed power means 25a and drive.

screw 23a to co-act with nut 27 mounted on carriage 21a and propel the carriage to a new bending location along horizontal work surface 9.

The places along horizontal work surface 9 where carriage 21a stops to begin a bending operation are controlled by pre-settable programming means. One embodiment thereof comprises a series (FIGS. 25 and mounted 26) of actuators 117 mounted on slide blocks 119, which are in threaded engagement with a series of guide rods 120 and horizontal positioning screws 121 arranged in parallel along the rear of frame 1 adjacent rear wall 5. On rear wall 5 of carriage 21 are mounted a series of limit switches 123 whose roller-ended arms 125 engage actuators 1 17 to start or stop certain operations of the machine such as carriage positioning, bending, etc. As shown in FIGS. 20 and'25, positioning screws 121 are journaled in vertical supports 127; the outboard end of the screws extending into drive box control unit 129 wherein they are turned by handwheels 131 to position slide blocks 119 therealong. FIG; 27 shows a typical arrangement of limit switches 123 and their respective roller-ended arms 125 on carriage rear wall 46. FIG. 28 shows a close-up view of a typical slide block 119 on guide rods 120 and in complimental threaded engagement with one positioning screw 121. Screw 121 is shown in engagement with block 119 through a nut 122 threaded on screw 121 and fixed to block 119. The other positioning screw 121 passes completely through block 119 without contact so that it may be used to position another slide block spaced apart from the block shown. Thus, there is no interference by positioning screws that pass through slide blocks 119.

Another embodiment of the pre-settable programming means comprises a means for controlling the rotation of drive screw 23a through a counter system. The length of carriagetravel may be measured by the pitch of the threads of drive screw 23a and the number of rotations of screw 23a. By combining a rotation counter with a memory system, the travel of carriage 21a may be controlled to stop at locations along the workpiece wherebends are to be made, await the completion of the bending operations, proceed to the next bending location, etc. This embodiment may be housed in a small panel at one end of the drive screw and would eliminate the use of a plurality of actuators and slide blocks that mayrequire frequent cleaning and other maintenance.

Shown in FIGS. 17, 18, andl9 is a means 172 for clamping or restraining the workpiece on work surface 9. In this particularembodiment, the means comprises a horizontal member supported on a vertical stanchion 167, fastened to frame front wall 3, that has a horizontal edge 169 substantially perpendicular to channel 11 so that it forms part of work surface 9. Edge 169 terminates at one end at a fixed upwardly extending clamp side 171 and at the other end with a movable upwardly extending clamp side 173. Movable clamp side 173 is mounted on a slideblock 175 that is complimentally and slidingly received on a horizontal rail 177 that extends from edge 169. Slide block 175 is connected to a power means 179 that comprises a hydraulic cylinder 181 and a piston rod 183; rod 183 is connected to slide block 175 and cylinder 181 is mounted on horizontal member by an adjustable connector 185.

A workpiece loaded into work'surface 9 would span edge 169. Energizing power means 179 causes movable clamp side 173 to move toward fixed clamp side 171 and clasp the workpiece on three sides;

Carriages

23a and 23b may thereafter move along the workpiece and bend it without jostling it out of precise position using the central clamping means just described.

A means for positioning the workpiece on the work surface comprises a feed stop and positioner 133,

mounted over horizontal work surface 9, and a stop arm 135 mounted on a rotatable shaft 137, housed in a channel 139, that is cantilevered from a vertical base 141 that is mounted for lateral travel by drive means 143 interposed base 141 and vertical stanchions 15. Drive means 143 comprises a horizontal rail 145 mounted along the rear of stanchions and a drive screw 147 arranged parallel to rail 145. A C-shaped saddle 149 encompasses rail 145 and screw 147 in complimental sliding relationship. A nut 151 is threaded onto screw 147 and is fixed to saddle 149. As screw 147 is turned by handwheel 153, base 141 is propelled traversely along rail 145. Feed stop 133 is adapted to be pivoted into a horizontal plane (shown in dotted lines in FIGS. 22 and 23) away from table 9 by a fifth power means 155 that comprises a hydraulic cylinder 157 whose piston rod 159 engages in eccentric arm 161 that is mounted on shaft 137; said hydraulic cylinder 157 pivoted about its rearward most end 163 on vertical base 141. Stop 133 is in a vertical position when piston rod 159 is extended its maximum length; it may be rotated out of perpendicularity with table 9 by causing piston rod 159 to withdraw into hydraulic cylinder 157.

The workpiece may be loaded onto work surface 9 from one end thereof from an extruder or other machine. The workpiece is moved forward along surface 9 until it strikes feed stop 133, set at a desired position. Thereafter, clamp means 172 is energized to hold the workpiece on surface 9 while

carriages

21a and 21b move into first operative positions near the ends of the workpiece and the bending dies form bends in the workpiece. Thereafter, the dies are retracted and the carriages quickly move inward to form a second pair of bends on the clamped workpiece, automatically and without the need of an operator. Four bends need not always be formed in the workpiece; the programming means may be preset to form any number of bends depending upon the desired configuration. Following formation of the last bends, the dies are automatically opened and the carriages move back to their initial positions. The anvil dies are also rotated to expel the workpiece so that it may be discharged from the bending machine.

I claim:

1. A machine for forming a series of bends in a workpiece wherein the bends are formed at pre-determined locations at high speed and without the aid of a machine operator, comprising:

a. a frame having a horizontal work surface spanning substantially the entire width thereof;

b. said frame having a horizontal track carried throughout the width of said frame supporting diecarrying carriages on each end of the frame for movement along the path defined by said track;

c. a drive screw carried on said frame connected to said die-carrying carriages and a power means for driving said drive screw to position said die carrying carriages at pre-selected locations along said frame to perform said series of bends in the workpiece;

d. said die-carrying carriages each comprising a base in mating sliding relationship with said track, said base carrying a vertical disposed carriage support plate;

e. an anvil die pivotedly mounted on said carriage support plate on a vertical pivot shaft rotatably mounted on the support plate, said anvil die forming a bending surface about which the workpiece is formed;

f. a retractable clamp slidably mounted on said carriage support plate for movement toward and away from said anvil die to position and retain said workpiece against said anvil die;

g. a gate pivotedly supported on said vertical pivot shaft for curvilinear movement through a horizontal arc about said carriage shaft;

h. a wiping die slidably mounted on said gate;

. i. means for positioning said wiping die adjacent said anvil die;

j. means for pivotedly moving said gate and wiping die about said anvil die;

k. means for automatically placing said carriages in operative relation to first positions near the ends of the workpiece;

l. means for automatically operating said clamp, said gate, and wiping die to form a first pair of bends in the workpiece;

m. means for automatically placing said carriages in operative relation to second positions further toward the center of the workpiece; and,

n. means for automatically operating said clamp, said gate, and wiping die to form a second pair of bends in the workpiece about said anvil die.

2. The machine of claim 1 including means for positioning the workpiece on the work surface including a feed stop positioned over said work surface and adapted to traverse therealong for stopping the travel of a workpiece loaded onto said work surface from the opposite end from said feed stop.

3. The machine of claim 1 wherein said means for automatically placing said carriages in operative relation to second positions further toward the center of the workpiece comprise a plurality of positioning screws arranged in parallel, spaced apart relationship, and substantially parallel to the major axis of said work surface, at least one sliding block in complimental threaded engagement therewith, means for restraining said block from movement other than along the longitudinal axis of said position screw, and switch means mounted on said carriage in spaced apart relationship to said block for pre-arranged contact therewith during movement of said carriage along said work surface.

4. The machine of claim 1 wherein said means for automatically placing said carriages in operative relation to second positions further toward the center of the workpiece comprise a counter for determining the position of said carriage with respect to the workpiece as a function of the rotation of said drive screw, means for programming another position of said carriage along the workpiece, and means for actuating said means for rotating said drive screw to move said carriage to the other position.

5. The machine of claim 1 wherein said anvil die is rotatably mounted and includes a non-workpiece contact portion for ejecting the workpiece therefrom.

face.

l I k

Claims

1. A machine for forming a series of bends in a workpiece wherein the bends are formed at pre-determined locations at high speed and without the aid of a machine operator, comprising: a. a frame having a horizontal work surface spanning substantially the entire width thereof; b. said frame having a horizontal track carried throughout the width of said frame supporting die-carrying carriages on each end of the frame for movement along the path defined by said track; c. a drive screw carried on said frame connected to said diecarrying carriages and a power means for driving said drive screw to position said die-carrying carriages at pre-selected locations along said frame to perform said series of bends in the workpiece; d. said die-carrying carriages each comprising a base in mating sliding relationship with said track, said base carrying a vertical disposed carriage support plate; e. an anvil die pivotedly mounted on said carriage support plate on a vertical pivot shaft rotatably mounted on the support plate, said anvil die forming a bending surface about which the workpiece is formed; f. a retractable clamp slidably mounted on said carriage support plate for movement toward and away from said anvil die to position and retain said workpiece against said anvil die; g. a gate pivotedly supported on said vertical pivot shaft for curvilinear movement through a horizontal arc about said carriage shaft; h. a wiping die slidably mounted on said gate; i. means for positioning said wiping die adjacent said anvil die; j. means for pivotedly moving said gate and wiping die about said anvil die; k. means for automatically placing said carriages in operative relation to first positions near the ends of the workpiece; l. means for automatically operating said clamp, said gate, and wiping die to form a first pair of bends in the workpiece; m. means for automatically placing said carriages in operative relation to second positions further toward the center of the workpiece; and, n. means for automatically operating said clamp, said gate, and wiping die to form a second pair of bends in the workpiece about said anvil die.

6. The machine of claim 1 including means for rotating said anvil die such that said working surface thereof is roTated out of contact with the workpiece thereby expelling the workpiece from reception in said anvil die and freeing said carriage for subsequent movement along said work surface to a new bending location.

7. The machine of claim 1 including independent means for restraining the workpiece on the work surface.