US2545976A - Machine for flaring or bending or spinning the edges of openings in sheets of stiff material - Google Patents

Description

2,545,976 7 MACHINE FOR FLARING OR BENDING OR SPINNING THE EDGES 0F OPENINGS IN SHEETS OF STIFF' MATERIAL Filed Jan. 9, 1946 C. T. SMALL March 20,

7 Sheets-Sheet l FIGZ.

ATTORNEY T. SMALL 2,545,976 MACHINE FOR FLARING OR BENDING OR SPINNING THE EDGES OF OPENINGS IN SHEETS OF STIFF'MATERIAL Filed Jan. 9, 1946 March 20, 1951 7 Sheets-Sheet 2 r- 4 I lIlIlIlIlIlIlIlIIIIIIIlIIIIIIII'IlIlll ,1. w.

INVENTUR: CHE SLEY T. SMALL,

ATT URNEY March 20, 1951 c. T. SMALL MACHINE FOR FLARING OR BENDING 0R SPINNING THE EDGES 0F OPENINGS IN SHEETS 0F STIFF MATERIAL 7 Sheets-Sheet 3 Filed Jan. 9, 1946 FIG.5.

I I I I I I I I I I I I I I I I I FIG I8 FIG I5.

mns mmmmmmmnmzmmmmmmmmmmmnmm-im ATTORNEY VIII/11111111111111 March 20, 1951 T. SMALL 2,545,976

MACHINE FOR FLARING 0R BENDING OR SPINNING THE EDGES 0F OPENINGS IN SHEETS OF STIFF MATERIAL 7 Sheets-Shet 4 Filed Jan. 9, 1946 FIG.8.

FIG .7.

FIG,6.

I l I INVENTOR C E EYTSMALL ATTORNEY March 20, 1951 c. T. SMALL 2,545,976

MACHINE FOR FLARING 0R BENDING OR SPINNING THE EDGES 0F OPENINGS IN SHEETS OF STIFF MATERIAL Filed Jan. 9, 1946 7 Sheets-Sheet v 5 T. SMALL 2,545,976 MACHINE FOR FLARING 0R BENDING OR SPINNING THE EDGES OF OPENINGS IN SHEETS 0F STIF'F MATERIAL Filed Jan. 9, 1946 March 20, 1951 7 Sheets-Sheet 6 INVENTOR TSMALL ATTORNEY March 20, 1951 c. T. SMALL MACHINE FOR FLARING OR BENDING 0R SPINNING THE EDGES OF OPENINGS IN SHEETS 0F STIFF MATERIAL Filed Jan. 9, 1946 7 Sheets-Sheet 7 F|G,l7.

INVENTOR SL EY TSMALL AT TO R NEY Patented Mar. 20, 1951 2,545,976 ICE MACHINE FOR FLARING R BENDING 0R SPINNING THE EDGES OF OPENINGS IN SHEETS OF STIFF MATERIAL Chesley T. Small, Memphis, Tenn, assignor to Memphis Metal Manufacturing 00., Inc., Memphis, Tenn, a corporation of Tennessee Application January 9, 1946, Serial No. 640,068

17 Claims.

My invention relates to a metal forming machine adapted, for example, to the manufacture of one-piece frames, often referred to as Venturi frames, for association with ventilating fans, and an important object of the invention is to provide mechanism for this purpose by means of which frames having any of the many desired orifice diameters can be formed in a single machine, not only as rapidly as by the common press and die method, but also entailing much less equipment cost than that involved in making separate dies for each desired size of frame orifice.

Other and more specific objects and advantages of my invention will be disclosed in the accompanying description.

In the drawings Figure 1 is a front elevational view of a suitable.

form of apparatus embodying my invention;

Figure 2 is a side elevational View, and Figure 3 a top plan View of the machine shown in Figure 1.

- Figure 4 is a horizontal sectional view on line 4-4 of Figure 1, and Figure 5 a horizontal sectional view on the line 5--5 of Figure 22.

Figure 6 is a vertical section on the line E--6 of Figure 4 and showing the main operating parts by means of which the frames are formed from a fiat sheet of metal which, before application to the machine, is provided with a central circular opening of suitable diameter.

Figure 7 is a detail elevational View of parts associated with the upper end of the main driving shaft which are indicated by the arrows l--! in Figure 6.

Figures 8 and 9 are horizontal sectional views along the lines 8-8 and 9--9, respectively, of Figure 6.

, Figure 10 is a section of some of the parts shown in Figure 6 but drawn to a larger scale and showing a forming roll and an associated 00- operating roller, some of the operating mechanism, and also showing the position of the work at the beginning of the operation of the forming of the Venturi portion of the fan frame.

.1 Figure 11 shows'a modified form of roller to cooperate with a forming roll.

Figure 12 is a sectional view along the line l.2l2 of Figure 6 showing a platform rotated by the drive shaft and uponwhich the slides carrying the forming rolls are adjustably mounted, a side elevational view of the platform at a point opposite one of the slide guideways being shown in Figure 13.

Figure 14 is a view corresponding to Figure 4 but illustrating another form of the work clamping structure Figure 14a is a sectional view on the line l=4al4a of Figure 14.

Figure 15 is a vertical section taken on th line l5-l5 of Figure 4 and detailing one of the work clamping devices shown in Figures 1, 2 and 4.

Figure 16 is a section along the line I6|6 of I Figure 10 and illustrates a slide supporting pedestal to be employed when machining the larger sizes of fan orifices.

Figure 17 is a plan View of a beading attachment which may be associated with the appa ratus for forming a bead on the outer edge of the frame orifice after the forming of the orifice has been completed by the machine.

Figures 18, 19, 20 and 21 further illustrate the beading mechanism, Figure 18 being a section on the line l8l8 of Figure 17; Figure 19 a detail 1 showing a beading roll; Figure 20 a section on the rather than on uprights carried by the machine base, and also illustrating the mounting of the drive motor in the lower part of the machine.

Figures 23 and 24 are side and front views of hooks attached to chains shown in Figure 22 for elevating the required parts to permit removal of a complete fan frame from the machine.

Referring first to the framing of the machine as Q shown more particularly by Figures 1, 2, 3 and 4, the numeral I indicates one side of the rectangular base; 2 is a platform supported above the base by the two vertical frame members 3 on the central part of opposite sides of the machine I and by the vertical frame members 4 at the corners. These uprights also support a platform 5 on which, in the form illustrated in Figures 1, 2 and 3, driving motor 6 is mounted. Suitably supported above the platform 2 is a work supporting bed plate 7 having a central circular opening for receiving parts of the frame forming mechanism to be hereinafter described.

A sheet of material 8 having a central opening therethrough, and from which a fan frame is to be formed, is shown on bed plate l and is clamped thereon by clamping plate 9 which is alsoprovided with a circular opening of slightly less diameter than the opening in the bed plate I (see Figure 10). Associated with this clamping plate 9 is means for elevating it, wires and pulleys for this purpose being shown, and to which wires counter weights such as it are preferably attached. The clamping plate 9 may be held in clamping position by a plurality of jacks l l (four being shown in the drawings) supported from the under side of platform 5. One of these jacks is illustrated partly in section in Figure 15.

The forming mechanism is actuated by a vertical shaft 12 journaled in the base of the ma-I chine as shown, for example, in Figure 6, and is driven by the motor 6 which, as illustrated in Figure 2, has a sprocket and chain connection with the pinion carrying drive shaft i3. A circular spider I4 is splined to shaft l2 and has at least three radial slots l8 (Figure 12). Detachable shoes l9 are secured to the spider adjacent the ends of slots l8 and constitute additional support for the spider rim on platform 2. At least three slides are slidably mounted on spider l4 and are held assembled therewith by guides ll bolted to the slides and received in the slots and overlapping the bottom of the spider. Each slide is provided with a supporting shoe 2| (Figures 10 and 16) resting on platform 2 (if a larger diameter Venturi frame is being produced, a longer slide is used. Each slide 26 carries a housing or support |5 which mounts a spindle |5a for journaling a forming roll IS with a concave face arranged to engage the portion of the work sheet 8 adjacent its circular opening.

As shown in Figure 6, a two-part sleeve 55 surrounding shaft |2 bears at its lower end on the hub of the shaft driving gear wheel 5'5, and between the upper end of this sleeve and the lower surface of the platform 2 a circular ball bearing 51 is positioned which serves as a thrust bearing against reaction forces tending to move shaft l2 upwardly during the operation of the machine.

Forked toggle arms 22 each pivoted at its forked end at opposite sides of one of the three roll housings l5 and at the other end to a sleeve element 23 vertically slidable on shaft l2, complete a mechanism for forcing the housings to slide on spider [4 toward or away from the shaft I2, depending upon the direction the sleeve is moved.

The upper end of shaft I2 is journaled in a vertically movable bearing 24 manually operable by the hand-wheel shaft 21 (see Figure 3) and the gear and rack mechanism shown, to be elevated to a position above the upper end of shaft I2 to permit the sheet which is to be formed into a fan frame (and which is provided with a central circular opening) to be inserted in position by passing it transversely of the shaft axis and between the bearing and the upper end of the shaft, and then down over the end of the shaft and over the forming rolls H5. The upper end of shaft I2 is in threaded relation with a sleeve 25. On the outer surface of sleeve 25 is a bushing 4| of friction material such as leather, for example, and which is clamped in frictional relation with the sleeve by a two-part clamp 42, the clamping pressure being regulated by bolts 43 joining the parts of the clamp. These clamp parts are formed with recesses on their edges which, in assembled position of the sleeve parts, form sockets 44 (Figure '7) into which may be inserted bars 45 whose outer ends are held from rotation with the rotating parts of the machine by contact with parts of the machine frame. When the bars 45 are out of sockets 44, sleeve 25 and associated parts rotate with the drive shaft, but when the bars are positioned in the sockets the friction clamp 42 is held from rotation and, therefore, sleeve 25 is either held stationary or slips to some extent with respect to. the friction bushing 4| but moves at a speed less than that of the shaft whereby, due to its threaded engagement with the shaft, sleeve 25 advances down wardly during the forming operation and, through a two-part ring 25., forces sleeve 23 downwardly and, through arms 22 and housings I5, actuates the forming rolls outwardly on their supports. The two-part ring 26 is clamped in frictional engagement at its ends with the lower end of sleeve 25 and the upper end of a collar 5| (see Figure 10) which contacts the upper end of sleeve 23. Ring 28 and collar 5| are positively held against rotation with respect to sleeve 25 by means of key pins 52 threaded in collar 5| and in sleeve 25, the heads of which pins engage in grooved parts of ring 26. After a fan frame is formed, the direction of motion of the drive shaft is reversed by reversing the rotation of the driving motor, and the threaded relation between sleeve 25 and the drive shaft causes return of the forming rolls to their initial position adjacent the shaft.

Referring now more particularly to Figure 10, each forming roll is journaled in the housing l5 for free rotation and the curvature in vertical direction of its outer surfaces conforms with the desired shape of the Venturi orifice in the fan frame. Associated with each formingroll is a cooperating roll 28 mounted, by means of ball bearings, for free rotation on arm 29 which is pivotally supported at 30 on the forming roll housing I5. By means of a pawl lever 3 I pivoted on arm 29 on the opposite side of pivot point 30 from roll 28, and the notched rack 32 with which said pawl cooperates, the operative clearance between the surfaces of rolls 28 and it may be adjusted. The arms 29 and associated parts, includ ing rolls 28, are removed after a fan frame has been formed to permit the taking of the completed frame out of the machine and the ap plication of another frame sheet. The removal of these arms 29 is rendered easy by means shown in which the top half of bearing 53 for the pivot pin 31' is held in position by the arm 54 operable by handles 54a and rotatable on pivot 54b, shown in dotted lines in Figure 10.

In the operation of the machine, which will be described with reference particularly to Figures 6 and 10, the clamping plate 9 is elevated to a point above the upper end of shaft l2 and the shaft bearing 24 is also elevated above the end of the shaft. A flat sheet of metal provided with a circular opening through its center, is inserted edgewise beneath bearing 24 and clamping plate 9 and over the upper end of shaft l2 until the sheet may be lowered towards bed plate 1 or 1a, as the case may be. As it is lowered, the edge of the circular opening in the sheet will come to rest on the lower portion of rolls l5 which have been adjusted radially of shaft I2 to engage and support the portion of the. sheet surrounding its opening. Sleeve 23 is then moved downwardly by arms 45 to shift rolls l5 radially of shaft |2- until the sheet is centered and lowered into 0011-...

tact with the supporting bed plate. Then clamp-. ing plate 9 is lowered and jacks II are actuated to clamp the work sheet between bed plate I and the clamping plate and securely hold the work sheet against rotation about shaft |'2 and against buckling. Bearing 24 is also lowered; to receive the upper end of shaft I2. The arms. 29 carrying rolls 28 are then applied and, by means of han dles indicated at 33 in dotted lines in Figure 10., are rotated on their pivots 30 to operative posi tion (in which the lowest part of the roller is adjacent the plane of the upper surface of the clamped portion of the work sheet)' the latter part of this rotation serving to press the part of the material of the sheet lying between each pairof rolls to the shape indicated in Figure l0. Power is then applied to rotate shaft I2 and, therefore, the platform carrying the rolls. This rotation causes the material entirely around the center opening to be initially flared to the extent shown in Figure 10, following which the ends of bars 45 are inserted into sockets 44 in clamping sleeve 42, and the sleeve member 25 is held against rotation at the same speed as the shaft and, therefore, due to its threaded engagement with the shaft, is caused to move downwardly and thereby also actuate sleeve 23 carrying the toggle arms 22 in a downward direction whereby these arms gradually advance the forming roll groups radially against the material of the sheet to be formed into a frame. This operation forces the material to advance underneath the supplementary rollersand upwardly along the contour of the forming rolls to form the desired flared portion-of the fan frame. The radial motion of the.

forming rolls can be continued until the material of the frame sheet has been forced to the top of the forming rolls or to any intermediate position, depending upon the desired length of the flare. The rate of motion of the forming rolls in radial direction during the spinning operation depends upon the speed of shaft I2 and the slip speed between shaft l2 and sleeve 25. The drive shaft may be operated at any desired speed during the forming or spinning operation, the rolls l6 and 28 being free to rotate on their supporting spindles.

a As previously stated, the frictional pressure of the leather friction bushing 4| on the surface of sleeve 25 can be varied by means of the bolts of the clamp 42. In forming frames the pressure on this friction bushing is preferably such that sleeve 25 does not slip with respect to the clamp 42, but when operating on heavy gauge material a slip may sometimes occur prior to the softening of the material due to the heat developed in the operation of the rolls thereon, after which the established frictional pressure on the friction element may become suflicient that the forming operation will continue at a suitable rate withto the forming roll may be modified and in Fig- I ure the plate Ea may be used as the bed plate and the plate 1 omitted. The initial position of the part of the work sheet 8 engaging the forming roll when la is used as the bed plate is indicated in dotted lines in Figure 10 which figure shows, in section, a spacer plate between I and 1a which would be removed when the latter is being used as a bed plate.

I I have shown in Figure 11 a modified form of roll 34 to cooperate with rolls It in lieu of the type of roll shown at 28. Roll 34 (which is shown as a composite of several zone-like pieces) has a spherical shape and all parts of the surface contacting with the outer face of the flare have a curvature concentric with the curvature in vertical direction of the surface of the forming roll. Figure 22 illustrates a modification in the framing of the machine in which the upper platform 5 is omitted, the means for elevating the clamping plate being supported from .the' ceiling or beam not connected drive motor being mounted on the base of the machine. Figure 5 is a horizontal sectional View on th line 5-5 of Figure 22 showing the driving connections between the motor and the main operating shaft l2 of the machine in this modification,

Figures 17 to 21, inclusive, illustrate a mechanism which can be attached to the machine for forming a head on the outer edge of the flared portion after it has been formed.

Referring to Figure 18, the beading mechanism comprises a supporting element 35 which may be bolted to housing l5 of one of the forming rolls and which supports header roll arms 36 (Figure 1'7), one of the header rolls being illustrated in Figure 19. As shown in Figure 17, a beader roll is positioned adjacent each side of the forming roll housing which carries them and by means of which they may be rotated around the up per edge of the flare after it has been formed by the forming rolls. To progressively depress the header rolls to form a bead on the edge of the flare, the element 35 carries a rod in threaded engagement with the frame element 3? to which the header roll arms 35 are clamped and this rod isv given a partial turn during each rotation of the machine in the beading operation by reason of the arm 38 attached to the rod being contacted by a pin 3?; slidably mounted on arm 44 which is detachably secured to a frame element of the machine (Figures 17 to 21).

Figures 14 and illustrate another arrangement in which cam-type clamping devices may be substituted for jacks H and each device 48 is pivotally supported on platform 2 by means of the sleeve portion 4'! mounted on a stud 43a having its ends "threaded into platform 2 and plate Ea. For use with this form of clamping device an angle iron 48 is applied to the upper surface of the clamping plate 9 and a clamping piece 49, applied to the clamping element 45 and provided with a bevel at its forward end, engages the upper edge of the angle iron. The position of the clamping piece 49 with respect to clamping element 43 is adjustable by means of the bolts shown. The clamping elements 46 may be rotated into and out of clamping relation with the angle iron clamping element 48 by means of lever 50.

I am aware that modification may be made in the apparatus herein described without departing from the principles of my invention and it is not intended that its scope be limited other than as set forth in the claims.

Having fully described my invention, that which I claim as novel anddesire to secure by Letters Patent of the United States is:

1. In apparatus for flaring the part of a sheet of metal surrounding a circular opening in said sheet, a drive shaft coaxial with said opening, a flaring element engageable with the edge of the metal defining said opening, means supporting said flaring element for revolution by the shaft, mechanism actuated by said shaft for applying force to said element to move it radially with respect to the shaft, said mechanism including a friction drive providing for variation in the ratio between revolutions of the flaring element about the shaft and the movement of the flaring eleflaring.

2. In apparatus for flaring the part of a sheet; of metal surrounding a. circular ,openingin said.

with the machine and the sheet, a drive shaft, a flaring roll for operative engagement with the part of the sheet surrounding the opening, roll supporting means extending radially from the shaft and revolved thereby and being adjustable toward and away from the shaft, a sleeve vertically movable on the shaft, a toggle arm pivotally connected at one end to said sleeve and at the other end to said roll supporting means, and means cooperating with the shaft and said sleeve to move the latter to actuate the flaring roll by said arm toward or away from the shaft.

3. In apparatus for flaring the part of a sheet of metal surrounding a circular opening in said sheet, a drive shaft, a flaring roll with a face concaved lengthwise of the shaft for operative engagement with the material surrounding the opening of the sheet, roll supporting means extending radially from the shaft and being adjustable toward and away from the shaft, a sleeve. vertically movable on the shaft, a toggle arm pivotally connected at one end to said sleeve and at the other end to said roll supporting means, means cooperating with the shaft and said sleeve to move the latter on the shaft to actuate the flaring roll by said arm toward or away from the shaft, a second roll of ball-like contour adapted to bear on the opposite side of the material from that contacted by the first roll, and means maintaining said second roll in fixed spaced relation with respect to the first roll and cooperative therewith to shape the work sheet between them.

4. In apparatus for flaring the part of a sheet of metal surrounding a circular opening in said sheet, a drive. shaft extending through said opening, a forming roll engageable with the edge of the metal defining said opening and having a work engaging face concaved lengthwise of the shaft, a second roll positioned on the opposite side of the material from that contacted by the forming roil and having a ball-like contour, means maintaining said rolls in fixed spaced relation during the flare forming operation, means supporting the rolls for revolution by the shaft, and means for moving the rolls radially with re spect to the shaft.

' 5. In apparatus for flaring the part of a sheet of metal surrounding a circular opening in said sheet, a drive shaft extending through said opening, a flaring element engageable with the edge of the metal defining said opening, means supporting said flaring element for revolution by the shaft and for movement radially with respect to the shaft, a sleeve in threaded engagement with the shaft, means connecting said sleeve with the flaring element to actuate said element radially with respect to the shaft, and means restraining the sleeve against rotation at shaft speed.

6. In apparatus for flaring the part of a sheet of metal surrounding a circular opening in said sheet, a drive shaft extending through said opening, a supporting element secured to the shaft for rotation therewith, a plurality of elements each mounted on said element and slidable thereon radially with respect to the shaft, a fixed platform supported beneath the supporting element, said element having downward extensions bearing on and slidable on said platform, a thrust bearing for the. shaft mounted on said platform, a sleeve on the drive shaft freely movable longitudinally thereof, toggle arms connecting each flaring element with said sleeve, a second sleeve in threaded engagement with the Bil shaft and connected to actuate said first sleeve longitudinally with respect to the shaft, and means preventing rotation of said second sleeve at shaft speed whereby said sleeve moves longi of metal surrounding a circular opening in said shaft, a drive shaft extending through said opening, a supporting element secured to the shaft for rotation therewith, a plurality of flaring elements each mounted on said supporting element and slidable thereon radially with respect to the shaft, a sleeve on said shaft freely movable longitudinally thereof, toggle arms connecting each flaring element with said sleeve, a second sleeve on the drive shaft in threaded engagement with the shaft and connected to actuate said first sleeve longitudinally with respect to the shaft, means preventing rotation of said second sleeve at shaft speed whereby said sleeve moves longitudinally with respect to the shaft and actuates the flaring elements in a direction radial to the shaft, a bed plate supporting the work sheet, and means for clamping the latter in position on the plate.

8. In a machine of the class described, spaced frame members, a shaft disposed vertically to said members, a bearing on each member for said shaft, one of said bearings being movable on its member towards and away from the other of said bearings to a projected position in which it receives one end of the shaft, and to a retracted position in which it is spaced from said shaft end, a carrier rotatable with said shaft, roll structure rotatably mounted on said carrier and revoluble. thereby about the shaft axis, and arranged to roll the edge of a circular opening in a work sheet surrounding said shaft.

9. In a machine of the class described, a lower platform, a shaft vertical to said platform and journalled thereon, a support on said platform for a work sheet having a circular opening surrounding said shaft, a carrier mounted on said shaft, roller structure mounted on said carrier for rolling the edge of said work sheet openhig, an upper platform spaced above the upper end of said shaft, a bearing member movably mounted on said upper platform to be projected downwardly therefrom to receive the upper end of the shaft, to support the same radially, and to be withdrawn upwardly to be spaced from the upper end of the shaft and thereby accommodate the insertion and removal of a work sheet edgewise over the upper end of the shaft and beneath the movable bearing so that the sheet may be lowered to and raised from a position in which its opening surrounds the shaft and roller.

10. In a machine of the class described, a frame, a rotatable shaft, bearings for said shaft on said frame and spaced apart longitudinally of the shaft and supporting the shaft against radial thrust, at least one of said bearings being arranged to surround an end portion of the shaft and being movable longitudinally of the shaft to a position in which the bearing is spaced from the end of the shaft to permit the passage of a work sheet over the end of the shaft, a work support between said shaft end andanother shaft bearing, a roller structure for forming the edge of a circular opening in the work sheet, mechanism associated with the shaft for revolving said roller structure about the shaft axis, mechanism 7 actuated by said shaft for moving said rollerstructure radially of the shaft against the edge of the work sheet opening, said roller structure and mechanism being positioned between said movable bearing and said work support.

11. In a machine for forming the metal about a circular opening in a work sheet, spaced frame members, a shaft disposed vertically to said members, roll structure mounted on and rotatable with said shaft and arranged to engage the edge of a circular opening in a work sheet surrounding the shaft, a shaft bearing mounted on each member, a work engaging element mounted on each member, the bearing and the work engaging element mounted on one of the frame members being movable on its associated member away from the bearing and work engaging element, respectively, mounted on the other frame member to a retracted position, in which the movable bearing and the associated work engaging element are spaced from the end of the shaft to accommodate the insertion of a work sheet between the end of the shaft and the movable bearingand work support, and said first-mentioned movable bearing and work engaging element then being movable towards said other bearing and work engaging element mounted on the other member to a position in which said movable bearing receives one end of the shaft and said movable work engaging element clamps the work sheet against the work engaging element on the other frame member.

12. In a machine for rolling the edge of a circular opening in a substantially flat work sheet, a central shaft, a substantially flat support for the work sheet surrounding said shaft and extending perpendicularly thereto, at least three rolls spaced apart at substantially equal angles about the shaft axis, means for revolving the rolls about said shaft, mechanism for moving said rolls radially of the shaft and away from each other to automatically center the edge of the work sheet opening about the shaft and then to form the edge of the opening, said mechanism including means providing for simultaneous equal movement of the rolls radially of the shaft, and elements for holding the centered work sheet against rotation about the shaft axis as it is being formed.

13. In a machine for rolling the edge of a circular opening in a substantially fiat work sheet, a central shaft, a substantially flat stationary support for the work sheet surrounding, said shaft and extending perpendicularly thereto, at least three rolls spaced apart at substantially equal angles about the shaft axis, means for revolving the rolls about said shaft, mechanism for moving said rolls radially of the shaft and away from each other, the diameter of the lower portion of each roll being substantially greater than the diameter of the upper portion of the roll and the rolls being spaced from the shaft so that the lower portions of the rolls engage the edge of the opening in the work sheet to support and to automatically center the sheet about said shaft, and means for clamping the work sheet to said stationary support.

14. In apparatus for flaring the part of a substantially flat sheet of stiff material surrounding 'a circular opening in the sheet, a substantially flat bed plate for supporting the sheet, means for clamping portions of the sheet spaced radially of the opening therein to said bed plate, at least three forming rolls engageable with the edge of the metal defining said opening and spaced substantially equal distances apart angularly about a central axis, means for revolving said rolls bodily about said axis, and mechanism for simultaneously moving said rolls equal distances only and parallel to the plane of said bed plate to progressively flare the material surrounding the opening in the sheet.

15. In a machine for rolling the edge of a circular opening in a substantially flat work sheet, a central shaft, a substantially flat bed plate surrounding the shaft and extending transversely thereof, at least three rolls spaced apart at substantially equal angles about the shaft axis and including surfaces inclined upwardly and inwardly to support a work sheet and to automatically center it about said shaft, means for lower ing the work sheet onto said bed plate comprising mechanism for moving said rolls towards said shaft, and structure for clamping the work sheet to said bed plate.

16. A machine as described in claim 8 which includes a substantially flat bed plate for supporting the work sheet, said plate being removable from the machine over the upper end of the shaft and transversely of its axis when the second-mentioned bearing is in the retracted position.

17. In a machine for flaring the part of a flat sheet of metal surrounding a circular opening in the sheet, a drive shaft about which the sheet opening may be disposed, a roll carrier movable radially away from and toward said drive shaft and revoluble about said drive shaft, a forming roll rotatably supported upon said carrier, and having a work engaging surface of concaved contour facing radially away from said drive shaft and means for moving said carrier and roll radially of said drive shaft, an arm pivoted on said carrier to swing one end towards and away from said roll, a second roll mounted on said arm end and having a ball-like contour corresponding to the concaved contour of said forming roll, a ratchet and pawl device holding said second roll against movement away from said forming roll, whereby said rolls may be held in position to receive the sheet between them and engage opposite faces of the sheet as it is flared upwardly by the outward movement of the forming roll.

CHESLEY T. SMALL.

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

UNITED STATES PATENTS Number Name Date 164,567 Laing June 15, 1875 173,808 Nugent Feb. 22, 1876 348,396 James Aug. 31, 1886 477,525 Ferrell June 21, 1892 743,644 Johnson Nov. 10, 1903 766,227 Doolittle Aug. 2, 1904 1,419,929 Jackson June 20, 1922 1,597,575 Bowman Aug. 24, .1926 1,872,294 Hothersall Aug. 16, 1932 1,896,156 Bond Feb. 7, 1933 2,045,235 Newman June 23, 1936 2,219,207 Goldthwaite Oct. 22, 1940 2,475,465 White July 5, 1949 FOREIGN PATENTS Number Country Date 15,970 Australia Apr. 25, 1904 4,931 Great Britain Nov. 10, 1881 31,129 Denmark Jan. 22, 1923 275,793 Germany June 27,1914

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