US1629233A - Automatic plate and sheet trimming and squaring machine - Google Patents

Description

' 1927. May F. H. STREINE AUTOMATIC PLATE AND SHEET TRIMMING AND SQUARING MACHINE 8 Shets-Sheet 1 Filed March 1 25 May 17, 1927. 1,629,233

F; H. STREINE AUTOMATIC PLATE AND SHEET TRIMMING AND SQUARING MACHINE Filed March 16. 1925 8 Shets-Sheet 2 I I am" ozawQwQ z dummy mz zss W F. H. STREINE AUTOMATIC PLATE AND SHEET TRIMMING AND SQUARING MACHINE Filed March 1 s Sheets-Sheet 3 [@II -0 o In uentor.

May 17, 1927. I 1 629,233

F. H. STREINE 7 AUTOMATIC PLATE AND SHEET TRIMMING AND SQUA-RING MACHINE Filed March '16. 1925 A a Sheets-Sheet 4 May 17, 1927.

F. H. STREINE AUTOMATIC PLATE AND SHEET TRIMMING AND SQUARING MACHINE Filed March 1 8 Sheets-Sheet 5 1,629 233 May 1927' F. H. STREINE AUTOMATIC PLATE AND SHEET TRIMMING AND SQUARING MACHINE Filed March 6. 1925 8 Sheets-Sheet 6 v gwumatoo May 17 1927. 1,629,233

F. H. STREINE AUTOMATIC PLATE AND SHEET TRI MMING AND SQUARING MACHINE Filed March 1 1 2 8-Sheets-Sh eet '7 TLC/17 1,629 233 May 1927' F. H. STREINE AUTOMATIC PLATE AND SHEET TRIMMING AND SQUARING MACHINE Filed March 1 8 Sheets-Sheet 8 .T I i I e L enema May 17, 1927...

result it. srnnms, or ivEw sanmnivyomo, Assmnon To THE srnnmn TOOL arm MANUFACTURING COMPANY, on NEW BREMEN, omo, a oonzeona'rron ononro.

AUTOMATIC PLATE AND SHEET TRIMMIN'G AND SQUARING MACHINE.

. Application filed March is, ieaaqseriai in. 15,925.

My invention has for its object to provide a machine lorshearing the edges of plate and sheet metal to remove the raw edges produced in rolling the metal to sheet or plate form. The invention provides ameanslor shifting the plates or packs of sheets to position for shearing oil the opposite raw edge portions and then shifting the plates or packs ol sheets to position to perform the same shearing operation on the remaining.

pair of edge portions along lines that "are at right angles to the shearing lines JOt'the preceding cuts made on the plates or packs of sheets and then delivering the plates or packs of sheets from the machine.

in the rolling mill operations, ordinarily followed. the raw, fish tail edges are removed by indiscriminately cutting by the 'nse of a shear, alongfirst'one side edge and then the other side edge, and then the end edges in succession. In. so doing. the edges,v

are not squared. since there is no means provided for guiding the operator in the ma-' nipulation of the sheetwhile it is being operated a; on by the shear, except the eye and his general judgment as to location of the sheet relative to the shear. This results not only in the sheet being trimmed and formed with edges'that are located at various angles that merely approximate 90, but also it results in a great waste of material since the sheet will be located at various positions relative to the shears. -Also subsequently the sheet must oe squared and a somewhat more accurate shearing operm tion is performed upon the sheet to' again trim metal therefrom to square the edges ot the sheet. This results in handling the sheets twice, turning thcnrinanually from one position to another in each handling and also in an enormous loss of material. By my in-' vention the packs of sheets or plates are merely "ted to the machine and the machine operates to cut opposite side edges parallel and subsequently cut the end edges parallel and at right angles to the side edges. and then deliver the plates or packs of sheets from the machine. Thus double handling of the sheets and the enormous waste involved in the ordinary trimming of packs of sheets and plates arceliminated. In the preferredtorm of my invention the opposite side edges are formed by shearing the said metal along the shearing lines at opposite edges at one and the same time by means of right and lett hand gate shears, that is, shearing devices that shear in the same direction from acommon edge which prevents creeping and cambering of themetal commonly caused by rotary shears and also tapering and cambering commonly" caused by single gate shearing operations. Furthermore, my invention provides a meanstor shearing from a single edge and along parallel edges which also prevents the shifting of the metal with-respect to the shears Thus my invention provides a means where by the edges are cut on straight llines'as distinct from curved'lines, and consequently the edges of the sheets are square-d one relative to the other." 1

The invention may be contained in trimming machines that vary in form and in structure and are designed and constructed for use in cutt ng sheets of different, lrinds of metal and of varied thicknessor packs of varied thickness. To illustrate and set forth an embodiment of my invention 1 have selected a structure containing my invention as an example ofthe different structures in which the invention may be embodied and shall describe it hereinafter. The structure "selected for purposes of illustration, is shown in the accompanying drawing.

Figure l is a top view ofthe machine. Fig. 2 illustrates a broken view showing the automatically adjustable roller bed for supporting the plates or sheets used in a part of the machine shown in Fig; 1 Fig. 3 illustrates automatically adjustable ball hearing supports forming a part of the bed, but in another partof the machine. Fig. t is a view of a sectiontaken on the plane of the line H indicated in Fig. 3. Fig. 5 illustrates a conveyor chain and a dog attached thereto which is used together with another conveyor chain having similar dogs for shifting the sheets through a part of the view of the mechanism shown in Fig. 7

Fig; .9 IS a side view of a main controlling switch for controlling the movements of the sheet and of the shear. Fig. 10 is a top View of the controlling switch illustrated in F ig. 9. Fig. 1]. is a top view of a switch for controlling the shifting and shearing mecha nism of another part of the machine. Fig. 12-is a side view of the switch shown in Fig.

. 11'. Fig. 13 is an. end view of the 'shearand a part of the conveyor bed. Fig. 19 illusroll controlling mechanism.

tratesan end view of the part shown in Fig. j

18; Fig. 20 is a view of a section taken on the plane of the line 2(l-20 indicated in Fig. 16. Fig. 21 is an illustration of one feed Fig. 22 is a conventional diagrammatic illustration of I the conveyor chains and the transfer supporting bed of the machine.

Fig. 23 is a diagram of the circuit connections between the controlling mechanisms of the machine.

In rolling mills, where metal plates or sheets are produced. the metal is rolled. either hot or cold and in the flattening operation of the metal the edges of the sheets and plates split and break to form serrations or irregular formations along the edges sometimes called fish tails and also the ends of the sheets and the plates, particularly, the following ends are drawn to irregular configurations or outlines in a manner well known in the rolling mill processes. \Vhen the metal is rolled thin to form sheets as distinct. from plates. the sheets may be secured together for convenience of handling by a. semi-welding operation along thev edges to form packs of sheets and so that when the packs are 'trimmedto remove the irregularities of the edges of the sheets the welded areas" of adjoining sheets are severed from the sheets. whereupon the sheets are liberated each from the other. In order that the raw edge portions may be removed from the plates or the packs of sheets. I have provided a shearing machine having shearing devices that will shear without crimping or bowing or distorting the metal and without twisting or turning the metal between pairs. of shearing devices or curving the edges valong either of the shearing devices. Hereinafter I shall refer to the packs of sheets and plates broadly as sheets or as sheet metal. unless I otherwise distinguish one from theother and by a. shear ing device I refer to a device that will shear and note single shearing blade or element which in itself cannot perform a shearing operat1on.- This latter is to avoid confusion with reference to the words shears or a menace pair of shears. These definitions have particular referenceto the claims hereinafter appended.

I The sheets may be placed upon a suitable table for convenience of feeding the sheets in succession to the machine. Par:

ticularly, where packs of the sheets are fed.

to the machine, leveling rollsmay be used for straightening the sheets to-elhninate the bulging in portions of the'sheets. In the form of construction shown the sheets are fed to the feeding rolls 1 of the typewell known in the art of sheet metal rolling operations. As the sheets are drawn between the rolls they ride upon'the conveyor 2. The feeding rolls and the conveyor 2 are driven by any suitable driving means such as the driving-motor motor 3 operates through the gear wheels 4 to drive the main drive shaft 5. The

shaft 5 operates'through chains 6' and 7 to drive the shaft 8. Theshaft 8 operates the chains 9 and drives the shaft 10. The conveyor 2 is driven by the shaft 10 and actuales the shaft 11. The shaft 11 operates on the chains 12 to drive the feed rollers] that directs the sheet metalon to the conveyor 2.

The feed rollers 1 are geared to each other through the. gears 33. The upper roller is supported on the arms 34 to allow for changes of thickness of the metal fed by the rollers. The upper rollers are spring pressed by springs 36 located in housings at the ends of the rollers. If desired the rollers maybe in the form of a plurality of disks that engage the sheets along parallel lines.

Un opposite sides of the conveyor 2 are located gate shearing devices 13 and 14C of the type well known in the art, which, however, are located face to face and have right and left "hand shears, namely. shears that are so disposed that they will cut from a single sheet when located in position by the conveyor 2. Preferably the shears of the shearing devices are so-located that they will cut from the leading end and'at the same rate beginning at the same instant to prevent creeping or twisting of the metal. The shearing devices 13 may be adjusted one relative to the other. Tn the form of construction shown the shearing device 13 isadjustable to and from the shearing device 14. The adjusting means for the shearing device 13 may comprise the screw 37 that will draw the shearing device-13 over the ha-se 15. The screw 37 is actuated by the main drive shaft 5 operating through the chains 38, the clutches 39, shafts 40 and 41 that are connected together by the miter gears 42.

The conveyor 2 is formed of a plurality of conveyor chains that move over sprockets located on the shafts 10 and 11. They move through channel bars 16 that rest upon the frame 17 and are connected together and to The the frames of the shearing devices 13 and 14- by means of the lazy tongs 18. The central portions of the links of the lazy tongs 18 are pivotallymonnected to the channel bars 16 whilethe'elicls of the lazy. tongs are connected to the frames of the shearing devices 13 and Hand so that'tvhen'the shearing place the sheet in position between the shears of the shearing device, a controll ng means is'operated whereby the conveyor 2 ceases to move the sheet further between the shearing devices until after the shearing devices'have operated. The conveyor 2. as heretofore stated, is driven by the shaft 1(),which is driven by the main drive shaft. 5 operating through the chains 6 and 7. the shaft 8 and tilt the chains 9'. The connection between the chains 6 and 19.- The'c'ontrolling means operated' by the sheet controls the connection between the chains 6 and 7 by shifting one or more parts of the clutch 19. The clutch TS) is for connecting or disconnecting the shaft and the sleeve 21, one of the members 22 of the clutch 19 being slip keyed to the shaft 20 while the other member 23 of thefclutch 19 is connected to the sleeve 21., and when .the'parts 22$ and23 are drawn into frictional contact-so 4', is controlled by the clutch asto frictionally engage one with the other,,

the parts of the clutch rotate together and consequently the chains 6 and 7 may be mechanically connected through the clutch 19, since the chain 6 is connected to the sleeve 21 while the chain T is connectedto the shaft 20.

The clutch parts 22 and 23 are drawn't-o gether by means of the yoke 24: whichis connected to the rod 25 which, is in turn cons nected thrbugh a link 26 to a lever 27. The

rod 25 is supported in a frame 28located on. a suitable part of the machine and the lever 27 is supported on the block 29, or other suitable pantof the machine, The lever 27 is operated by a cam 30 to draw the rod 25 against the spring 31 which is located b.e tween a collar 32 and one end of theframe 28. \Vhen the lever 27 is released from'the raised portion of the cam 30 the spring 31 operates to separate the clutch members22 and 23 and disconnect the chains 6 and 7.'

During the period of disconnection of the chains 6 and 7. the conveyor 2 is'at rest and consequently the chain is stationary.- During the period that the lever 27 is thus'released means is provided for operating the S lQtll'lIU! devices tocut the side edges of. the sheet This is performed by means of suit able trips .43 thatare connected to the shaft through the arms 44 and the .shaft 64 which is connected to the trips 43 by means of the arms 96. (Figs. 16 and 17.)

The shaft 35 is operated bymeans of the cam 45 which operates: to actuate the arm .46 connected to the sha-ft,35. The .cains 30 and 4-5 are located on the shaft 47 and consequently are timed so as to produce operations of the shaft 35 when the lever 27 is releasedfrom the raised portion of the cam 30,namely; during the time that the sheets The cams 30- and a5 are oper-' are at rest. ated by meansrof the worm gearing 48 that drives the shaft 47; The worm gearing is driven bv the motor, 49. The motor 49 is I connected in a suitable circuit to periodically actuatethe cam shaft 47 and to thuscontrol the connection. of the conveyor with the main'driving motor 3 and the tripping of the shearing devices. Inasmuch as the motor 42 is required to operate only at the ex jnrfitloti of periods ofpredetermined and aldprstable lengths, a means is provided for connecting the motor with the main circuit at the expiration of the said periods. Since the sheet metal must be positioned in the predetermined position. particularly accord ing to its length, before the said edge p0rtions are removed. the motor 49 is controlled by.a;switch that is operated by the sheets.

Also 'since"-releasement of the switch after the operation of the shearing device is des red, theswitch is preferably'operated by tliat-poi'tlonof the sheet which is subsequentlysevere-d from the sheet by one of the shearing. devices, and so that upon the drop ping away of the portion sheared off the switchwill be released. Thus the control is shifted from the {switch to a mechanism that controls the operation of the shearing device which provides for a complete operation of the shearing device at the end of each of the said periods and thus a complete "cycle of operations of the machine is insured.

The switch used for controlling the con- ,vevor andthe shearing devices, is shown in Figs. 9, and 1(). It is mounted on a suitable bracket. 50 which may be secured to a part of th'oframe of the machine. cylinder 51 is pilvotallysupported. in a box 52 that is connectcd tothe bracket 50. 'l lie cylinder. 51 is provided with contacts 53 tliat' are suitably connected, together A pair of spring con-- tacts 54' are se cuixed to the hex 52 and elec-.

tricrlly insulatedifrom each otherby means of the plate. The contacts 54 may be" provided withsuitable binding posts 56 for cvlinder '51- is providedjwi'th the crank formed by the bars 57- that are connected by meanskrf the link 58 with a lever 59.

connecting theswitch with'a circuit. .The

lvl' vement of the lever hi l-will cause the cvlinder 51 to oscillate and close the circuit Ive-:5 tween the contacts 54 by the contacts The lever 59 is pivoted to the bracket and, is resiliently returned by means or "the spring which normally holds the'lever 59 against the stop 61 which is secured to the bracket 50 and thus normally retains the contacts 53 in an open position with respect to the contacts 54. \Vhen the lever 59 is moved from this normal position it closes the circuit through the contacts 54. The

lever 59 is provided with a finger 62 that is located in the path of movement of an edge portion of the sheet 63 as it is conveyed through the machine and so that the edge portion which is to be severed by one of the shearing devices will engage 1 the. finger 62,

to operate the switch to close the circuit of the motor 49 when the sheet 63 has reached the predetermined position with respect to the shearing devices. This closes the circuit of the motor 49 as shown in Fig. 23. The

motor49 then actuates the shaft- 47 to dis-;

connect the chains 6 and 7 and consequently discontinue movement of the sheet and sub- 7 sequently to trip the shearing devices 13 and 14 through the operation of the shait35; As shown in Fig. 23 the motor is connected in a three 'wire circuit, the parts of the mo- ,tor being connected to one of the mains whereby the movement of the cylinder 51 of the sheet controlled'switch will connect one part of the motor 49 and when the edge portion of the metal is severed from the sheet that partotthe circuit will be opened. ,The

opening of the circuit by movement of the cylinder 51, however, does not occur until t after the motor 49 has been actuated for. a

' cuit' through th-ecmotor.

period of time, that is, until'after the high portion of the cam 30 has passed the end of the lever 27, and after the cam 70 has-released the roller'71 to close the switch which completes the other part of the cir- The motor con-- tinues to operate until the saidother 'part. of the circuit through the motor is opened.

. It is opened by 'meansof the switch 65 which is located in a box 66 and is provided with a pair of contacts 67 and 68. The con tact 67 is actuated bymeans of the rod 69 which is operated by the cam 70. lVhen the cam 70 strikes the roller "71 located on-,the end of the rod 69 the'cam pushes the rod down to openl the switch 65 and consequently stop the motor at a point where the cam 70 holdsthe switch inyan open position. 'Both of the circuits through the motor 49 are then open and consequently the motor 49 ceases to operate. The motor ceases its operation when the lever 27 has been moved to aposition to close the clutch members 22 and 23 and thus the conveyor 2 again inoves the sheet, the edge portions having been severed therefrom.

The sheet is then carried by the conveyor 2 from between the shearing devices 13 and 14 and is directed upon the conveyor 72,

, sheets.

which is driven by the chains 6 and 7 and theshat't 8 to which the chains of the cone veyor 72 are connected. The conveyor 72 moves the sheet to the feed rollers 73. .The feed roller-73 cooperates with-the conveyor 72 to engage and move 'th sheet to the transfer table 74. The feed ro ler 7 3 is driven by the'shat't 8 operating through gears similar )to gears 33 shown in Fig. 21;

The transfer table'74 is formed oi a p rality of bars 76'tl1at are interconnected by linkswhich with the bars 76 form an expan- 'sion or lazy ton g device whereby the bars inav be spaced uniformly each from the other according to the distance between the ends of the interconnected links 77.- Cross pieces 78 are located on each of the bars 76. The bars 76 are 'slidable on the bars 79 that form a part of the frame of the machine and the bars '76 have lugs or small brackets 80 that engage the bars 79. This prevents any irregular formation of the general contour of the transfer table i4 due to dilleren cein friction of the parts of thelinks that are pivotally connected to the bars 76. The ends of each series of the links '37 are connected to the frames 81 of the shearing devices 82,

and 83 that are used to shear the ends of the The frames 81 are adjustable one relative to the other to provide for shearing the end portions of sheets of different lengths. Preferably the shearing device 83 is made adjustable relative to the supporting frameor base 15. Thus the shearing device 83 may be'shit'ted by any suitable screw- 111g device 83 is drawn fromthe shearing device 82 to produce uniform support througl'iout the sheet notwithstanding the adjustments that-may be made by the shifting of the shearing device 83.

'The transfer table 74 is provided with a plurality of balls 85- that are-supported on the cross pieces 78. The balls 85 may be supported in cups 86in which are located ball bearing rings 87 so that the balls 8ii' may rotate in any direction as the sheet placed by the conveyors on to the transfer table 74 and then moved therefrom. Also the plates88 located at ends of the table 74 may be secured to the frames 81 and similar ball bearing cups 86 may be supported on the plates 88 so as to receive the end portions of the sheet.

seas-nae I 'When the has been placed upon the transfer table '74 it'is conveyed by means of the chains 90 and the dogs 91 between/ theshearing devices 82 and, 83 where the ends of the sheets are trimmed. Thus the sheet is moved ina direction at right angles to the,

direction that it was conveyed'by the con- I veyors. 2 and 72 and between the shearing devices 82 and 83 thathave shearing blades located parallel to eachotheriand in lines that are at right angles to theshearing lines o in which the edges of the shearing blades of the shearing devices 13 and-14 are located.

As the sheet is conveyed from the transfer table 7 1 it is uniformly supported through out its area by means of the bars 92 that are provided with the, rollers 93. The bars 92 are supported onthe bars 94 that form parts 7 of the supporting frame/of. the machine.

The bars are maintainedin their proportionately spaced relation by means of the links 95 whichare pivoted attheir centers to the bars 92and are 'interconnectedtoform a chain that is connected at its ends to the frames 81 ot' the shearing devices-82 and 83.

'The bars 92 arefv also provided with suitable lugs 80 that prevent endwise movement of the bars 92 relative tothe cross bars 94, and consequently the chain of links95. that inter-' connect the bars 92 form a. lazy tong expane sion for the proportionate disposition of the bars 92, as the frames 81 are separated one from the other. The chains- 90 move in channel bars 75 and aredrivenby the shaft 81.; The shaft 84 is connectedtoithe main drive shaft 5' through the'miter gears 96, the clutch 98, sprocket chain 99, shaftlOO, miter gears 101, shaft. 102, miter gears103, shaft 104, miter gears 105, and the shaft 5, the main drive shaft.

and move them to positions such that'the side edges formed by the shearingdevlces 13 and 14 will be at right angles to the cutting edges of the blades of the shearing devices, 82 and 83, and push the sheets between the shearin' devices 82 and 83.

The sheet moves on to the table 74 until it passes from between the roller 7 3 and the conveyor 72. The movement of the conveyor chains, 90 is controlled by a switch 106. The swltch has an arm 107 that is en-, v

gaged by the sheet to'close the contacts of the switch when the sheet ,is delivered on to the table 74. The switch is formedof a cylinder 108 that has one or more contacts, such as the contacts 109 that are adapted tomake contact with the spring contacts 110 when the cylinder is turned by the arm 107. This closes a circuit thzough asolenoid 111 "which tilts the lever 112 which permits in- 7 tel-engagement of the clutch parts 113 of the clutch 114.. (Figs. 13 and 14). The clutch operates the cam 115 which; in turn operates theflever 116, the link 117;the lever 118,

The dogs-91 are so dis posed as to periodically engage the "sheets:

sheet, a conveyor the link 119 and tlie lever 120 which permits I v the clutch 96 to complete the connection beare connected tripping mechanisms to trip the shearing devices 82 and83 in the same manner and with similar mechanisms that the shearing devices 13 and 1 1 are tripped 4 by the trip shaft 54: referred "to-above. The

shaft 126 operates the trip or clutches of the shearing devices '82 and 83 to cause the devices to trim the end edge portions of the sheet and to raise the shears totheir normal positions as controlled by their trip clutches. The clutch 114 is constructed in the same way that the trip clntchescf the shearing devices are constructed, that is, to cause a single revolution of'th'c shaft connected to the driving means by the clutch. The clutch parts make a complete revolution before the lever 112 may again enter to disconnect the clutch parts and permit the sheet to remain" in position while the shearing devices 82 and 83 are operating on the sheet. When a succeeding sheet is again moved on to the transfer table 74 and operates the switch 106, the conveyor chains 90 are again moved to convey the sheet from between the shear-' ing devices and from the machine and to.

move the succeeding sheet to the shearing position. I

The switch 106 is located in a box 130 which is supported on an elastic bar 131 having a sloping end adapted to guide the sheets sothat their ends Wlll strike the lever 107, and insurethe operation of the switch a 1. In an automatic sheet metal trimming machine, right and left'hand shear devices located in horizontally ,spaced relation,

means for feeding the sheet materialbetween the-shears and means operated by the moving sheet for discontinuingthe-operationof the feeding means and causing ,theoperation of the shearing devices. Y

2. In-an automatic. he et metal trimming h right l t hand, S earing de- Vices 'flliged'in horizontally. spaced re1 tion fOI ShQQIifig bfp'posite side edges of the or moving the sheet between the shearing devices-and into position for having its'sideedges sheared, means operated by the moving sheet for stopping the conveyor, means for causing the operation of has. been completed.

"12 5 the shears'and fo'r starting the-conveyor in Y its op ration when the shearingoperation' 3. In an automatic sheet metal trimming andsquaring machine, two pairs of shearing devices, one pair of shearing devices for .ing dev-ices, one pair of shearing devices for trimming the side edges of the sheets, the

other pair 'of'shearing devices for trimming the ends of the sheets, a pair of conveyor means for conveying the sheets successively between the pairs of trimming devices, -a pair of controlling means, one for causing the operation of the first pair of shearing devices and for controlling the movement of the conveying means that conveys the sheets between the said first pair of shearing devices, and the other controlling means for controlling the operation of the second pair of shearing devices and for controlling the conveying means that conveys the sheets be tween the last named pair of shearingidevices.

5. In an automatic sheet metal trimming machine, a pair of shearing devices, means *for conveying the sheets between the said shearing devices, a switch operated by the said sheet at a, predetermined point in the movement of the sheet through the said shearing devices, a driving means for operating the said conveying means and the said shearing devices, an electric means controlled by the said switch for discontinuing the operation of the conveyor and connecting the shearing devices with the vdrivlng means;

6. In an automatic metal trimming machine, a pair of shearing devices, means for conveying the sheets between the said shearing devices, a switch operated by the said sheet at a predeterminedpoint in the movement, of the sheet through the .said shearing devices, a driving means for oper ating the said conveying means and the said shearing devices,- an electrically controlled clutch controlled by the said switchfor discontinuing the operation of the conveyor and connecting the shearing devices with the driving means, and for subsequently delivering the sheet from the said shearing devices.

7. Inan automatic sheet metal trinnning and squaring machine, two pairs of shearing devices, one pair of shearing devices being located in lines parallel to each other and the other pair of shearing devices being located in .linesparallel to each other and at rightangles to the shearing lines 3 of said first pair of shearing devices, and.

a. conveyingfmeans for conveying the sheets between the pairs of the shearing devices.

for controlling the conveying means for sitioning the sheet during succeeding penode of operations of the shearing devices on the said sheets.

9. In an automatic sheet metal trimming and squaring machine, two pairs of shearing devices, one pair of shearing devices being located in lines parallel to each other and at right angles to the shearing lines of the other pair of shearing devices, a conveying means for conveying the sheets between the pairs of the shearing devices, and a controlling means for conveying the sheets between the pairs of shearing devices invsuccession and discontinuing the operations of the con veying means during. the successive operations of the shearing devices on the said sheets. I

10. In an automatic sheet metal trimming machine, a shearing device, an electrically operated conveying means for conveying the sheets to the shearing device, a switch for controlling the operations or" the conveyor and of the shearing device and operated by the movement of the sheets and positioned to be engaged and released by the metal sheared from the sheet by one of the shearing devices.

11. In an automatic sheet metal trimming and squaring machine, a pair of gate shearing devices, and feeding means for conveying sheets between the shearing devices, the shearing blades of the shearing devices being supported for-shearing in a direction coextensive with the direction of feeding movement of the sheets i "12. In an automatic sheet metal trimming machine, two pairs of shearing devices for cutting opposite side and end edges of a sheet, the shearing blades of each pair of shearing devices being supported to shear in a direction away from asingle edge of the sheet.

13. In an automatic sheet metal trimming shearing devices of each pair relative to each other, and a conveyor means for corn. veying the sheets successlvcly between the pairs of shearing devlces.

In testimony whereof I have hereunto signed my name to this specification.

FRANK H. srnnmii} nit

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