US2973796A - Cleat flanger for sheet metal ducts and the like - Google Patents

Description

March 7, 1961 c. F. ENGEL ETAL CLEAT FLANGER FOR SHEET METAL DCTS AND THE LIKE Filed June 26, 1959 FIG. I.

ENGEL AYND BONARD V. MACE B N VEN TORS CHA R I ES FIGZ.

ATTORNEY March 7, 1961 c. F. ENGEL ETAL 2,973,796

CLEAT FLANGER FOR SHEET METAL DUCTS AND THE LIKE Filed June 26, 1959 6 Sheets-Sheet 2 FIG. 3.

IOI/

FIG. 4.

INVENTORS CHARLES F. ENGEL AND BONARD V. MACE ATTORNEY March 7, 1961 c. F. ENGEL ErAL CLEAT FLANGER FOR SHEET METAL DUCTS AND THE LIKE 6 Sheets-Sheet 15 Filed June 26, 1.959

FIG. Il.

INVENTORS CHARLES F. ENGEL AND BONARD V. MACE FIG 6 BY TORNEY March 7, 1961 c. F. ENGEL ETAL CLEAT FLANGER FOR SHEET METAL DUCTS AND THE LIKE Filed June 2e, 1959 GVSheets-Sheet 4 ATTORNEY March 7, 1961 c. F. ENGEL ETAL 2,973,796

CLEAT FLANGER FOR SHEET METAL DUcTs AND THE LIKE Filed June 26, 1959 6 Sheets-Sheet 5 l 1 1 l| .ll/WTE :II JJM .w ,J Y d. j mpv D@n s www u G f Mw A J AB f F AW.

March 7, 1961 c. F. ENGEL ETAL 2,973,796

CLEAT FLANGER FOR SHEET METAL DUCTS AND THE LIKE Filed June 26, 1959 6 Sheets-Sheet 6 :Nvu/mns cH Les F. ENGEL AND NARD v. MACE ATTORNEY I United? Safe een o @e .aan

CLEAT FLANGER FOR SHEET METAL DUCTS AND THE LIKE Charles F. Engel, Columbia, and Bonard V. Mace, Alton, Ill., assignors to Engel Sheet Metal Equipment, lne., St. Louis, Mo., a corporation of Missouri Filed June 26, 1959, Ser. No. 823,133

14 Claims. (Cl. 153-4) Ilhe present invention relates to 'apparatus for bending 180 flanges on the margins of sheet metal work pieces, and is particularly adapted to the bending of so-called cleat flanges on the end margins of rectangular sheet metal ducts. -Such flanges are utilized on both ends of duct sections to secure the abutting section ends to each other by drive cleats, the usual practice has been to bend such flanges only to 90 by machine, and then hammer them back to 180 using a hand tool. `In contrast to such usual practice, the present invention yields perfectly proportioned and aligned flanges, automatically, reliably, and almost instantaneously, without requiring a skilled operator.

The apparatus here provided consists generally of a work support `surface terminating in a blade having a free edge, unsupported on its under side for a width sufficient to permit the bending of the flange around and back against the under side. Hold-down fingers, pivoted on an axis above and beyond the edge of the work, extend into the duct section to clamp it to the support surface, accommodating the upstanding walls of such a rectangular duct.

Slots, correspondingly spaced, are provided in a gage portion of a first rotating wiping bar, and also in its wiping surface. This rotating wiper bar is pivoted on an axis beyond the edge of the blade and in or near the plane of the work support surface. This first wiper bar wipes the margin of the sheet metal to a 90 downward flange and releases it. A second wiper bar, located beneath the plane of work support surface, engages the flange so formed, despite Vspringbackof the metal, and wipes it to the 180 position.

A cam mechanism, rotating with the wiper bars, draws the hold-down fingers tightly against the work as the operation commences, and lifts them upwardly at the end of the operation. Provision is made for operation by powered operation, in two differently timed sequences. The first is by a reciprocating mechanism, in which a first stroke of a piston engages the clamping fingers and wipes the flange to approximately 90, and a return stroke of the piston wipes the flange to 180 and lifts the holddown fingers.. The second is by a rotary power mecha nisrn such as an electric motor, which performs the operations in sequence by rotation in a single sense.

The apparatus thus supports the weight of the duct, and provides a sturdy blade edge and parallel upper and lower surfaces adjacent the edge about which cleat flanges may be turned. The lower surface of the duct section is clamped by the clamping means onto the work support, so that its margin projects over the sturdy edge. Gaging means are presented at the precise distance from the edge necessary for accurate flange spacing. First wiper means flange the projecting margin downwardly over the edge, at approximately a 90 angle; while correspondingly spaced gaps in the clamping means and downward wiping means permit those surfaces of the duct which extend upward from the surface being flanged to be accommodated during the clamping and wiping. Second wiper means then wipe the flange around and back- V ward under the same edge. Powering and sequencing means operate the clamping means, gaging means, downward wiping means and backward wiping means in such sequence that the clamping means is raised when the, gage means is presented at flange-spacing distance, and lowered into clamping position and held there until the downward-wiping and backward-wiping operations are completed. When the clamping means raises, the work may be removed by sliding it to disengage the 180 flange from the blade edge.

in the accompanying drawings: f

Figure l is a plan view of apparatus embodying the present invention and powered by a reciprocating piston. The dashed lines show a duct section in place fol*r ilanging.

Figure 2 is a sideelevation corresponding to Figure 1, the arcuate dashedline showing the travel of the clevis end of the reciprocating piston shaft.

Figure 3 is an enlarged fragmentary view taken alongl line '3-3 of Figure 2.

Figure 4 is a further enlarged view showing how the seam of a rectangular duct is accommodated in a notch of one hold-down finger. j

Figure 5 is a fragmentary view, still further enlarged, taken along line 5 5 of Figure 3 showing the parts when la duct section is inserted against the gage angle preparatory to flanging. The cam mechanism which engages and releases the hold-down fingers is shown in dashed lines.

Figure 6 is a somewhat schematic view showing the positions of the principal operating parts in sequence following Figure 5, that is, when the clamping fingers first engage. Y

Figure 7 is a following sequential view showing the positions of said parts when the flange is wiped downward to at the end of the first stroke of the reciprocating piston.

Figure 8 is a following sequential view showing the positions of the parts when the flange has been wip'edto on the return stroke of the piston. Y v

Figure 9 is a following sequential view showing the parts at the close of the` returnv stroke ofthe piston, and.Y

the flanged duct being removed. y

Figure 10 is an enlarged fragmentary cross-sectionV taken along line 10-10 of Figure 7, showing the eccentric mounting of the cam follower roller.

Figures 1l and 12 are fragmentary views of the gagev erecting mechanism, VKin positions corresponding to Figures 5 and 9 respectively. i

Figure 13 is a schematic view of a partly finished rectangular duct, having cleat flanges bent back 180 on two p Figure 16 is an enlargedr fragmentary view, partly,KV schematic, taken along line 16-16 of Figure 14 and; showing the position of the hold-down fingers, hold-down .l

actuatingcam and follower mechanism, and the wiper bars when an unilanged duct is being inserted in position for flanging; also showing a simple wiring diagram;

Figure 17 is a sequential view similar'to Figure16- showing the hold-down ngers engaged and the gage porf tion of the first wiper ba-r withdrawn.

Figure 18 is a following sequential view ,similarlyg Ashowing the relative position of the parts at the completion of the wiping of the flange through a 90 angle.4

Figure 19vis a following sequential vriewshowing the` 3 positggns of the parts at the time of wiping the flange to 1 Figure is a following sequential view of the close of the fianging operation showing the parts in position for removal of a fianged work piece.

Referring now to the drawings by detail part numbers, there is provided a horizontal planar work support table surface 21 to support the work pieces. The work table surface 21 is itself supported by horizontal frame members 22 and vertical legs 23. As shown at the right side of Figure 2, there is an offset-and frame support 24 which extends parallel to the surface 21 but at a lower level, joined to the frame members 22 by depending angle bracket 25.

Upon the offset frame support 24 are mounted two parallel angles 26 and 27 which extend the full width of the work support surface 21 but beneath its level. Bolted to the upstanding flange of the inner of these angles 26, as by bolts 37, is the depending flange 36 of a work table edge angle 28, rigidly formed of heavy steel to resist the applied clamping force as hereinafter described. It is machined so that its upper surface 29 adjacent to the planar table 21 lies in the same plane, but having a recessed portion 30 at the other side, and extending the entire width of the work support surface 21, as to accommodate therein a flat rugged steel blade 31 with its upper surface in the plane of the table surface 21.

The width of the blade 31 is greater than that of the recessed portion 30, so that a lower surface margin 32 of the blade 31 projects beyond the table edge angle 2S a distance at least equal to the width of the 180 flange to be formed on work pieces.

Countersunk screws 33 hold the blade 31 securely in the recessed portion 30 in the work table edge angle 28. In effect the blade 31 forms a slender continuation of the edge angle 28 cantilevered securely outward to establish a bending position at the blade edge 34, with the under blade surface margin 32 free; the assembly being of sufficient rigidity to resist the wiping action without undue deflection. The work table edge angle 28 is shaped for maximum rigidity by providing a tapered under surface 35 extending toward the under blade surface margin 32, formed convex for clearance of other parts to be described.

The ends of the angle 28 are supported by a plurality of countersunk mounting screws 38, between a pair of rigid vertical end plates 39, which are mounted securely at both sides of the machine onto the several frame portions and particularly to the inner frame angle 26 and the outer frame angle 27. An upper tie bar 57 makes the spacing of the end plates 39 more secure. These end plates 39 are drilled and bushed to provide the several axes of rotation for the mechanical elements of the machine hereafter described.

The uppermost of these several axes of rotation is the axis 40 of a pivoted hold-down assembly generally designated 41. The axis 40 is parallel to, above and beyond the blade edge 34, the term ,beyond in the sense that it is not above but rather outward of the work support surface on which the work piece is to be supported.

The principal portion of the hold-down assembly 41 is a member which is preferably made by welding or as a st eel casting. It consists of a shaft portion 42 whose length is greater than the spacing of the end plates 39 and which has shaft ends 43 supported in bushings in the end plate 39 and passing therethrough. Between the end plates 39, the holddown assembly 41 includes an integral finger-clamp portion 44 whose upper surface projects from the axis 40, toward the work support surface 21. When the assembly is held in clamping position as shown in Figure 6, the upper surface 45 is nearly horizontal. A nearly vertical surface 46 extends downwardly therefrom terminating in a lower clamping surface 47 which is presented horizontally and flatly against a work piece on top of the upper surface of theblade 31 when in the clamping position shown in Figure 6. The fingerclamp portion 44 further has an arcuate under surface 4S curving upward from its clamping surface 47 toward the shaft portion 42 in an arc, so as to accommodate the first wiper bar hereinafter described.

The surfaces 4S, 46, 47 and 48 are interrupted by providing the finger-clamp portion 44 with spaced gaps or slots 49 as shown in Figures 1 and 3, which slots 49 terminate in slot margins 50 as shown in Figure 5. The slot margins 50 are located beyond the blade edge 34 at a distance greater than the width which an unflanged margin of the work piece will overhang. This permits the slots 49 to accept and accommodate the vertical duct Walls and permit movement to slip the formed flange off the blade 31 as shown in Figure 9 and remove the duct.

The slots 49 thus divide the finger clamp assembly 44 into a plurality of heavy projecting fingers 51, and divide the clamping surface 47 into a number of fingertip portions 52. As shown in Figure 3, each of these is provided with at least one shallow cutout 53 adjacent an edge, to accommodate a Pittsburgh lock seam s as shown in Figure 4.

The slots `49 are spaced at convenient intervals so that variations of duct width may be accommodated. Thus the intervals between the first four slots 49 at the right of Figure 3 are less than the intervals between the remaining gaps or slots 49. A duct section designated d is inserted in place for hanging by presenting its vertical walls into slots 49 and wherever they will fit, utilizing a combination of the smaller intervals and larger intervals as necessary.

It is important that the 'finger-clamp portion 44 bc rigid. For this purpose there may be secured by end screws 54 as shown in Figure 3, a bridging tension bar S5. This extends over the fingers 51 to a point inwardly of the gap margin 50, as shown in Figure 5, and is drilled and tapped from top to bottom to receive a plurality of separately adjustable tension screws 56, whose tips may be adjusted to bear downward on the upper surface portions 45 of several of the fingers S1.

Hold-down operating lever arms 58 are rigidly secured onto the shaft portions 43 which project outwardly from the mounting bushings in the end plates 39. The lever arms 58 are rectangular in cross section. Each has a slot 59 into its projecting end, which divides the end into tines 60, which may be drawn clampingly toward each other by an adjustment screw 61. At their inner ends each slot 59 enters into a clamping bore 62, which clampingly solds the base portion 63 of an eccentrically mounted roller pin 64 on which a cam follower rollcr 65 is rotatably mounted.

An axis established by bushings through the end plates 39 at about the level of the work support surface 2l `and under the hold-down assembly axis 40, is referred to as the first wiper bar axis 66. On it is mounted a first wiper bar, generally designated 67, and formed preferably as a steel casting. Its length is greater than the distance between the end plates 39, having aligned cylindrical shaft-like end portions 68 which serve as trunnions for mounting it on the axis 66. Between the end plates 39 it is nearly oblong in cross-section, to minimize bending when wiper pressure is applied, and has a leading edge wiper surface portion 69 which sweeps curvingly outward to a constant radius surface portion 70, The distance from the axis 66 to the surface of the constant radius portion is less than the distance of the `axis 66 to the blade edge 34, by an amount which exceeds slightly the thickness of the heaviest metal to be flanged on the machine. In the wiping operation, the wiper bar 68 is rotated so that the wiper surface leading edge portion 69 first contacts the margin of the sheet metal which overhangs the blade edge 34, to bend it downward over the blade edge 34; and the constant radius anveres portion 70 completes the wiping of a flange to a 90 angle.

Secured to the said rst wiper bar 67 are an elongated gage hinge bracket 71 and a number of aligned projecting hinge stop pins 71. These project horizontally toward, and slightly above the level of, the table surface 21 when the iirst wiper bar 67 is at the beginning and end of its stroke, as shown in Figures and 9. Horizontal hinge pins 72, pivoted in the hinge bracket 771, are aligned with each other beneath the hinge stop pins 71. About the horizontal hinge pins 72 `are coiled torsionv springs 72'; and onto the hinge pins 72 is secured the horizontal flange of a retractable gage angle 73, which the torsion springs 72' urge clockwise outward toward at contact against the under sides of the hinge stop pins 71. The gage Iangle 73 terminates in a gaging flange 73 which is presented vertically downward when the parts are in position to receive a work piece for flanging as shown in Figure 5. The gaging ange 73 is thus parallel to the blade edge 34, and is presented at a distance therefrom which determines the flange spacing or flange width.

As the first wiper bar 67 rocks counterclockwise, the gage angle 73 is drawn downward out of the way, the clamping fingers tip portions 52 engaging as in Figure 6. if the corner notches of the duct section being gaged are fairly small, as shown in Figure 5, further clearance may be provided by notching the apex of the retractable gage 73 slightly to provide clearance for the edges of the vertical walls of such duct. The notches would be located correspondingly to the slots between the holddown lingers 51.

During the portion of the cycle that the work piece margin is wiped downward to 90 angle, as shown in Figure 7, the unflanged vertical walls of the duct d would themselves prevent the hanging operation were it not for the fact that the leading edge wiper surface 69 yand the constant radius portion 70 are provided with wiper bar slots or gaps 74, likewise spaced correspondingly to the slots or gaps 49 between the lingers 51. The gaps 74 have gap margins 75 which are located at a depth within the wiper bar 67 sufficient to provide clearance for the edges of such vertical walls as the bar rotates. Such gap margins 75 are therefore preferably formed at a constant radius about the first wiper bar axis 66.

One of the end portions 68 of the rst wiper bar 67 extends beyond the bushing which holds it. in end plate 39, and is there equipped with the spur gear 76. This gear is in mesh with a second spur gear 77 of equal diameter, secured to an outstanding shaft portion 78 of a second wiper bar 79. This, like the first wiper bar 67, is an integral casting which extends the entire breadth of the machine and is lsupported on shaft-like end portions 78, in bushings in the end plates 39, on a second wiper bar axis 80, thus it is maintained parallel to the first wiper bar axis 66, and is located beneath the blade edge 34 about the same distance that the first wiper bar axis 66 is outwardly from said edge. The relative positions lof the parts are shown in Figures 5 to 9 in their various sequential working relationships.

The general conguration and construction of the second wiper bar 79 is similar to that of the first wiper bar 67 in general, save that there is no gaging surface nor any slots.l The cross-sectional shape of the second wiper bar 79 is thus constant between its shaft portion V78 in which it is mounted in the end plates 39. It has a leading edge 81 which initiates the second wiping action. Following theY leading edge 81, the wiper surface extends farther radially outward, to a constant radius portion 82, terminating in a trailing. edge 83 which completes the wiping operation against the under surface margin 32 of the blade 31, as shown in Figure 8. The trailing edge 83 of the second wiper bar 79 then passes beyond the ange and into the removal position shown in FigureY 9.

Extending inwardly from the leading edge 81, the secv ond wiper bar 79 is provided with a notch 81', thus to accommodate springback from the downward anged position shown in Figure 7.

Inasmuch as the rst spur gear 76 and the second spur gear 77 are of the same diameter, the rotation of s the iirst wiper bar 67 and the second wiper bar 79 will be the same in angular amount ,but their senses of rotation will be opposite. Reviewing the sequence of operations of the said wiper bar from Figures 5 through 9 inclusive: from Figure 5 through Figure 7, the second wipe the flange from 90 to 180. The respective wiper bars come to rest in the positions shown for them in Figure 9.

The mechanisms by which the said wiper bars are ro-V I *tated together in opposite senses, includes the spur gears '76 andv 77; also the crank arm 84 which is securely mounted by ra crank arm collar 85 onto the outer end of the outstanding shaft portion 78 as shown in Figure 2; also the piston rod `clevis end fitting 86, pinned to the outer end of the crank arm 84, whereby the motion of a reciprocating piston shaft 87, `operating in the reversible pneumatic cylinder assembly 88, is Vtransformed into a cranking motion. By means of a control valve 89 actuated through a foot pedal control 90, air under pressure is supplied to both ends of the reversible cylinder assembly 88 through flexible hoses 91. The cylinder assembly S8 is mounted to the frame members by a lateral pivot pin 92 supported in a heavy frame bracket 92'. The crank arm 84 has the travel 'shown in the arcuate dashed line in Figure 2. A rst inward stroke of the piston shaft 37 rotates the second wiper bar 79 clockwise and the spur gearing drives the first wiper bar 67 counterclockwise, from the position shown in Figure 5 to the position shown in Figure 7. The return stroke of the shaft 87 drives the parts from the position shown in Figure 7, back through the stage shown in Figure 8 Mounted on the outstanding shaft portions 78 at both ends of the second wiper bar 79, are heavy steel discs 93 to which are mounted, by countersunk screws 94, an outer cam track 95 which extends for a portion of the periphery of the steel disc 93. Its inner edge 96 and entrant portions 97 serve as the cam surface which engage the cam follower roller 65. In the angular gap between the entrant portions 97 the follower roller 65 is free from the cam track; and an inner thrust cam 98, whose outline is best shown in Figure 7, thrusts the roller outward from the second wiper bar axis 80, as shown in FiguresV 5 and 9, at the beginning' and ending of the sequence. However, for clamping during the sequence of the operations as shown in Figures 7 and 8, a cam track entrant portion 97 first draws the roller 65 inward and then the cam track inner edge 96 holds-the cam follower roller 65 at a constant distance from Ythe second wiper bar axis 80.

This constant distance corresponds to the downwardclamped position of the hold-down operating lever arm 58, as shown in Figures 6, 7 Yand 8. Adjustment for for tightness and for variation of material thickness Ais made by setting the eccentric pin base 63 of the cam follower roller 65 to elfect suitable tightness. The thrust the hold-down fingers are cycle isv initiated.

As the second wiper bar 79 forms the flange toi 180;?,KVV

as shown in Figure 8, the first wiper bar 67 has returned clockwise to within 20 or so to the starting position shown in Figure 5. At this point the upper surface of the retractable gage angle 73 strikes the inner end of a gage stop pin 99 projected horizontaliy from the bore of a bracket 99' mounted on the inward side of one of the end plates 39. Secured to the stop pin 99 inwardly of its end portions are inner and outer stop collars 160, 100'. A spring and lever release mechanism, generally designated 101, controls the stop pin 99 in the manne; hereinafter described.

When the gage angle 73 is in gaging position as shown in Figure 5, the inner end of the stop pin 99 rides against an end surface 73, pressed thereagainst by the coiled spring 161 which is compressed between the inner collar 100 and the bracket 99. As the first wiper bar 67 rocks counterclockwise to carry the gage angle 73 downward, the stop pin 99 rides over the end surface 73" and springs into position over the end of the gage angle 73, as shown in Figure 12. The continued counterclockwise rotation of the first wiper bar 67 draws the gage angle 73 downward away from the projecting stop pin 99.

With the reversal of the sense of rotation on the return of the first wiper bar 67 to the position shown in Figure 12 (that is, about the stage of operations shown in Figure 8) the upper surface of the gage angle 73 strikes against the projecting pin 99 and stops its upward travel. As the first wiper bar 67 continues its clockwise travel to the close of the return stroke, as shown in Figure 9, the stop pin 99 continues to hold the gage angle 73 downward, against the resistance of the torsion spring 72. Figure 9 shows the gage angle 73 held downward, well out of the way of the duct section d; which is then removed by sliding the formed 180 fiange forward to disengage it from the blade edge 34.

Before inserting another workpiece, the spring and release lever mechanism 101 is actuated to release the gage angle 73, in the following manner: The lever 101 is pressed against the outer collar 196', thus drawing the pin 99 outward, so that the torsion springs 72 thrust the gage angle 73 upward against the now horizontal hinge stop pins 71. The gage angle 73 is then in position to gage another workpiece, as shown in Figures and 11.

Figure 13 shows the end of a rectangular duct section d which is already partly flanged. When the sheet from which the duct d is formed was still in iat pattern, corner notches n were provided. The Pittsburgh lock seam is designated s. Two of the surfaces of the duct, shown with flanges f are already formed backwards at 180; while the other two surfaces are shown with unflanged margins lz.

Thus, the embodiment shown in Figures 14 to 20 inclusive not merely substitutes electricity as the motivepower, but provides for the rotation of the first and second wiper bars in the same sense, in a somewhat different angular relationship or timing; and also provides a stopping position, at the close of the iianging cycle, differs from the starting position principally in that no gaging element is near. The mechanism shown in similar to the first-described embodiment save for the gearing, the precise arrangement of the cams with reference to the gears, the connguration of the gaging portion of the first wiper bar, and the cyclic relationship between the two Wiper bars. To the extent that parts are the same as in the preceding embodiment, they may not be renumbered or may show corresponding numbers.

In this modified embodiment, a vertical bracket 102 reinforces the frame adjacent to the .leg 23 near the axes of the parts to be driven, and a motor support bracket 102 bridges the vertical support 102' and the adjacent leg 23, to support an electric motor 103 having a gear reduction 104 by which power is suppled to the machine through a driving spur gear S. rl`he motor f l'ed with electric power from a source not shown. The gear reduction 104 may itself include a familiar brake mechanism which is therefore not shown, or other braking mechanisms may be provided, so that the driven parts may be stopped at a precise angular position.

Supported by the end plates 39, on an idler axis 106 equidistant from the axes 66, li() of the first and second wiper bars 67, 79 respectively is an idler gear stub shaft 107 bearing an idler gear 168 by which power is trans` mitted from the driving spur gear to the upper and lower wiper bar gears 109, 110 respectively, driving them in the same sense and at the same speed, both in a counterclockwise direction.

The first wiper bar 67 is similar to the first wiper bar 67 of the embodiment described before insofar as the provisions which relate to wiping functions are con cerned. A different arrangement is made for gaging, however; thus the 4first wiper 67 has an integrally cast lip 111 including an arcuate gaging lip surface 112 formed at a constant radius from the first wiper bar axis 66.` rl`he arcuate gaging lip surface 112 is located immediately in advance of the wiper surface leading edge 69'. With the axis 66 of the first wiper bar 67 located in the plane of the work support surface 21, it is optional to slot the surface 112 for the removal position is different in this embodiment than the gaging position.

The second or lower wiper bar 79 is here identical with the wiper bar 79 of the first described embodiment. The two wiper bars 67', 79 are so connected by the described gearing that the first wiper bar 67 leads the second wiper bar 79' by approximately 300.

Figure 16 shows the gaging position, with the duct margin to be flanged contacting the arcuate lip surface 112; Figure 17 shows the positions of the parts with the wiper surface leading edge 69 about to wipe the flange downward; Figure 18 shows the completion of the downward wiping portion of the operation; Figure 19 shows the second wiper bar 79 wiping the flange backward 180; and Figure 20 shows the second wiper bar 79 after completion of the wiping, with the first wiper bar 67 extending nearly vertically upward, well out of the way of the duct section d shown as being removed.

Timed operation of the holddown operating lever arms S8 is by rotary cam mechanism quite similar to those heretofore described but which in this instance turn through 360 each complete cycle. Thus each of the two rotary cam discs 93 has fixed thereto an outer cam track 95' which includes a lead-in cam portion 113 by which the cam follower roller 65 is drawn inward toward the axis 80. Following the lead-in cam portion 113 is a constant radius cam portion 114, which extends through that angular portion of the cycle represented by Figures 17, 18 and 19; and the track 95 terminates in a release portion 115 similar to the lead-in portion 113.

Set between the lead-in cam portion 113 and the release portion 115, but inwardly of the roller 65', is an inner thrust cam 116 having a thrust camming surface 117 which is so curved as to drive the roller 65 outward from the axis 80 as the roller 65 passes the release portion 115 of the cam 9S. The thrust cam 116 permits the roller 65 to drop back towards center as the lead-in cam portion 113 is reached. By this means, the hold-down operating lever arm 58' actuates the holddown assembly 41 clampingly downward as the cycle progresses from the material insert position shown in Figure 16 to the clamping position shown in Figure 17, and the hold-down assembly 41 is then held clampiugly in place until after the flange is finally formed as in Figure 19, and is then released in the material removal position shown in Figure 20.

For the purpose of effecting control to start and stop the motor 103 at proper angularity, any one of a variety of electric hook-ups, may be used. Shown in Figure 16 is a simplified arrangement, in which one of the discs 9 93' is provided with an external switch-operating lobe 118. Two normally-closed switches 119, 120 have switch operating arms 121 equipped with follower rollers 122 which follow the outer periphery of the disc 93' in switch-closed position, but are successively opened upon contact with the lobe 118.

The switches 119, 120 are shown in Figure 16 as connected in parallel; and they'are alternately put into circuit by a double-throw toggle control switch 123. To start the motor 103 to begin the hold-down and fianging cycle, the operator throws the control toggle switch 123 to one side so as to engage switch 119 and place it in series with the motor 103 and the source of electrical current. The moving parts would thus be driven through the positions shown in Figures 17, 18 and 19 to the final removal position shown in Figure 20, at which the lobe 118 would open switch 119, cutting off the current supply to the motor 103. The operator then removes the anged part. Prior to inserting another part for ilanging, the operator throws the toggle control switch 123 to the other side so as to put the other switch 120 in circuit; and it transmits current to the motor 103 to drive the parts from their positions shown in Figure 20 to those shown in Figure 16, at which the lobe 118 opens the switch 120, again interrupting the source of current supply to the motor 103, The machine is then in position for inserting another part to be iianged.

Other modifications in construction, and other utilizations, will occur to those skilled in the art. Accordingly, the present invention is not to be construed narrowly, but as fully co-extensive with the claims hereof.

We claim:

l. Apparatus to form 180 flanges on margins of sheet metal, comprising work support means, means providing an edge and parallel upper and lower surfaces adjacent thereto about which a 180 fiangemay be turned, means whereby to clamp a sheet of metal onto the work support means in a position wherein its margin projects over said edge, and to release same, means presentable at a ange-spacing distance from said edge whereby to gage the projection of such margin prior to flanging, means to wipe such margin downwardly adjacent to the edge, means to wipe such margin from such downwardly-extending position, backward around and under the edge-providing means, and means to operate the clamping means, gaging means, downward-wiping means, and backward-wiping means in such sequence that the clamping means is raised when the gage means is so presented at flange-spacingdistance and is lowered into clamping position ,thereafter and until the downwardwiping and. backward-wiping operations are completed.

2. Apparatus to form cleat flanges on duct edges, comprising work support means, means providing lan edge and parallel upper and lower surfaces adjacent thereto about which a cleat flange may be turned, means wherebyv to clamp the lower surface of a duct section onto the work support means in a position wherein the margin of such surface projects over said edge, and to release same, means presentable at a fiange-spacing distance from said edge whereby to gage the projection of such lower surface prior to ilanging, means to wipe the margin of such lower surface downwardly adjacent to the edge, correspondingly spaced gaps in said clamping means and downward wiping means whereby the duct surfaces extending upward from its lower surface may be accommodated during such clamping and wiping, means to wipe a fiange so formed downwardly, backward around and under the edge-providing means, and means to operate the clamping means, gaging means, downward-wiping means, and backward-wiping means in such sequence that the clamping means is raised when the gage means is so presented at flange-spacing distance, and is lowered into clamping position thereafter and until the downward-wiping and backward-wiping operations are completed.

3. Apparatus for bending 180 flanges on the ends of rectangular ducts, comprising means Vto support work` in a plane, a blade having an upper surface in the plane of the work support, alower surface, and a free edge connecting said surfaces and projecting away from the work support, a hold-down assembly pivoted on an axis parallel to, above and beyond the edge and having spaced finger portions projecting over the edge, said hold-down assembly further having an operating lever arm, a first wiper bar having ay wiper surface slotted correspondingly to the spaces between the finger portions, means whereby the first wiper bar is pivotally mounted parallel to the edge and so spaced with reference thereto that its wiper surface will wipe a angle with reference to the upper surface of the blade, a second wiper bar having a wiper surface and means mounting said second wiper bar parallel toV and at a level beneath the edge, and so spaced with reference thereto as to wipe around said blade edge from 90 to 180, a material gage mounted on a wiper bar and having a gage surface presentable in a gaging position across the plane of the work support parallel to and spaced from the blade edge, said surface being rotatable away from said gaging position,

wiper bar drive mechanism whereby the first and second wiper bar Surfaces are successively brought into wiping engagement and withdrawn, a cam follower mounted onto the operating lever arm of the hold-down assembly, and a rotary cam driven by the drive mechanism and having a cam surface engaging said cam follower to lower the hold-down assembly toward the plane of the work support during the successive engagement of said first and second wiper bar surfaces and to raise said assembly following their successive engagement.

4. Apparatus for bending Vcleat anges on the ends of rectangular ducts, comprising means to work in a plane, a blade having an upper surface in the plane of the work support, a lowersurface and a'free edge connecting said surfaces andiprojecting away from the Ywork support, a hold-down assembly pivoted on an axis parallel to, above and beyond the edge and having spaced ringer portions projecting over the edge, said hold-down assembly having an operating lever arm, a first wiper bar having a wiper surface slotted correspondingly to the spaces between the finger portions means whereby the first wiper is pivotally mounted parallel to the edge and so spaced with reference thereto that its wiper surface will wipe an angle downward with reference to the upper surface of the blade, a material gage, a second wiper bar having a wiper surface andk means mounting said second wiper bar parallel to and at a level beneath the edge, and so spaced with reference thereto as to wipe around and under said blade edge, mechanism whereby the said wiper bars are rotated simultaneously one clockwise and the other counterclockwise, said mechanism including a'powered piston, a shaft- Vmounted crank arm linked thereto, and gearing whereby the" first wiper bar surface is vbrought into wiping engage,- ment during one stroke of the piston and the second is brought into wiping engagement during the pistons return stroke, together with cam means whereby the hold-down finger portions are lowered at the beginning of the first Y said stroke and raised at the close of the second said stroke.

5. Apparatus forrbending cleat fianges on the ends of rectangular ducts, comprising means to support work in a plane, a blade having an upper surface in they plane of the work support, a lower surface and a free edge connecting said surfaces and projecting'away from the work support, a hold-down assembly pivoted on an axis parallel to, above and beyond the edge and having spaced finger portions projecting over'. the edge, said hold-down assembly having an operating lever arm, a first wiper bar having a wiper surface slotted corerspondingly to the spaces between the finger portions, means whereby the first wiper bar is pivotally mounted parallel to the edge and so spaced with reference thereto that its wiper surface will wipe an agrar/9e angle downward with reference to the upper surface of the blade, `a material gage mounted on the iirst wiper bar having a gage surface slotted correspondingly to the spacings between the finger portions and presentable across the plane of the work support parallel to and spaced from the blade edge, a second wiper bar having a wiper surface and means mounting said second wiper bar parallel to and at a level beneath the edge, and so spaced with reference thereto as to wipe around and under said blade edge, mechanism whereby said wiper bars are rotated simultaneously in the same direction of rotation, said mechanism including a motor and drive mechanism whereby the first and second wiper bar surfaces are successively brought into wiping engagement and withdrawn and whereby the material engage is presented across the plane of the work support before and after the engagement by the two wiper bars, a cam follower mounted into the operating lever arm of the hold-down assembly, a rotary cam driven by the drive mechanism `and having a cam surface engaging said cam follower to lower the holddown assembly toward the plane of the work support during the successive engagement of said rst and second wiper bar surfaces to raise said hold-down assembly following their successive engagement, and motor control means whereby the motor is stopped when the hold-down assembly is raised.

6. Apparatus for forming 180 flanges on margins of bendable sheet material, comprising a work support terminating in a blade having an upper surface in the plane of the work support, a blade edge, and a blade under surface unsupported adjacent to the edge, further having gaging means presentable in a gaging position spaced from said edge a distance determinative of the width of the flange to be formed, hold-down means, first means for wiping a ange downward against the blade edge, second means for wiping such flange backward against the blade under surface, and driving means timing the engagement of the hold-down means with the two said wiping means and the release of the hold-down means with the presentation of the gaging means in gaging position.

7. Apparatus as defined in claim 6, the blade edge being unsupported on its under surface for a distance as great as the width of the flange to be wiped backward thereagainst.

8. Apparatus for forming 180 anges outwardly on the margins of the ends of rectangular sheet-metal duct sections, comprising apparatus as defined in claim 6, the hold-down means and downward wiping means having a plurality of correspondingly spaced gaps perpendicular to the work support and extending therein at least as far as said gaging position, whereby to provide clearance for vertically-extending walls of such rectangular duct sections.

9. Apparatus for forming 180 flanges outwardly on the margins of the ends of rectangular sheet-metal duct sections, comprising apparatus as defined in claim` 6, the

l1olddown means and downward wiping means having a plurality of correspondingly spaced gaps perpendicular to the work support and extending therein at least as far as said gaging position, whereby to provide clearance for vertically-extending walls of such rectangular duct sections, together with gage means atlixed to said tirst wiper means and having a plurality of corresponding spaced gaps.

10. Apparatus as defined in claim 6, the hold-down means having a pivot axis parallel to, above and outwardly from the blade edge and including finger portions projecting toward and operable downwardly against the work support for clamping therebetween.

11. Apparatus as defined in claim 6, both said wiping means having rotatable shafts, such timing of the holddown means being actuated by a cam rotating with the said shafts.

12. Apparatus as defined in claim 6, the second wiping means being pivoted on an axis and having a leading edge and a notch extending from adjacent said edge toward the said axis, within which notch any spring-back of the downward-wiped ange may be accommodated.

13. Apparatus as defined in claim 6, the said wiping means being pivoted on parallel axes and mechanically interconnected to rotate one clockwise and the other counterclockwise, the driving means including a reversible driving piston on whose rst stroke the hold-down means is clamped downwardly, the second wiper is rocked back, and the rst wiper is brought into wiping engagement, and on whose return stroke the first wiper is raised, the second wiper is brought into wiping engagement, and the hold-down means is raised.

14. Apparatus as detned in claim 6, the said wiping means being pivoted on parallel axes and mechanically interconnected to rotate in the same direction of rotation, the driving means including a motor engageable to effect such rotation, the said actuation of the hold-down means being effected by a cam plate rotating with said wiping means, said cam plate including a pressure apply cani having a constant radius portion extending around the greater part of its perimeter, whereby clamping force is supplied to the hold-down means, and motor control means whereby rotation is interrupted when the cam releases such clamping force.

References Cited in the tile of this patent UNITED STATES PATENTS

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