US3555949A

US3555949A - Die cutting presses

Info

Publication number: US3555949A
Authority: US
Inventors: Ernest H Treff
Original assignee: FL Smithe Machine Co Inc
Current assignee: FL Smithe Machine Co Inc
Priority date: 1965-04-02
Filing date: 1969-12-05
Publication date: 1971-01-19
Anticipated expiration: 1988-01-19

Abstract

An ejector assembly for the cutting die of envelope blank forming machinery in which an hydraulically operated doubleacting piston operates to rotate the die and ejector plate as a unit, the latter being capable of rotational movement of 360*. Stationary conduits are connected to a source of pressurized fluid for the piston so that the latter may be selectively raised or lowered.

Description

Unitedstates- Patent [50] Field of Search Inventor Ernest l-l. Treff 83/123- Port Washington, NY. 126, 128, 137, 97, 561, 562, 390; 100/218 Appl. No. 878,997 Filed Dec. 5, 1969 [56] References Cited Patented Jan. 19, 1971 UNITED STATES PATENTS Assignee Smith Machine $0., 2,173,358 9/1939 Ernst 100/218X New 3,157,111 11/1964 Anderson 83/123X a corporal New 3,344,697 10/1967 Schneider 83/1 37x Continuation of application'Ser. No. 580,599 Sept 18, 1967, now abandoned Primary ExammerJames M. Melster which is a division of application Ser. No. Attorney-None and None 444,960, Apr. 2, 1965, now Patent No. 3,370,492.

ABSTRACT: An ejector assembly for the cutting die of en- E E velope blank forming machinery in which an hydraulically a raw 1 operated double-acting piston operates to rotate the die and U.S. Cl. 83/125, ejector plate as a unit, the latter being capable of rotational 83/137, 83/390, 83/561 movement of 360. Stationary conduits are connected to 21 Int. Cl. B26d 7/16, source of pressurized fluid for the piston so that the latter may B26f 1140 be selectively raised or lowered.

AM y 42 PATENTH) urals?! v sum Om @"W' WM v a r v M 5 TTORNEYS .PATENTEU Jam I371- I saw us for 12 Y q L INVENTOR 3m W E? %%N sum 10 [1F 1 PATENTEU JAN 1 91971 Mm mm 1 I 23 I 1 .15- 40 .7 T :1 296 I 0 1L. i 4

sum 11 or 1 2 Repay I 3Z5 INVENTOR ERNEST A 725;;

Wall %4 ATTORNEYS 33,555,949 "sum- 12 or 12 PATENTEDJM 1 9197ii ATTORNEYS 1 01E currmorasssss This application is ancontinuation of application Ser. No.

68() ,599 filedsept l ii, 19.67,;now abandoned, which in turn is a division of.application Ser. No. 444,960, filed Apr. 2, 19 65,now ufir,Pht-.;No. 3,370,492. I i

ute ourriuo masses The presentinventionrelates to die cutting presseswhich are adapted to-be used for cutting throughsheet material so as to cut the sheet material1 inte sections of predetermined configuration, although the principles of the invention can also be applied to machines .whichdo not necessarily cut through the sheet material but instead'simply provide an impression-of a the invention can also be used in the shoe industry for cutting through leather sheets or fabric sheets, as well as for cutting through paper sheets towprovide labels of a given configuration, and in addition the machine of the invention canbe used for cutting through sheets of gasket material for providing gaskfilfi Qfi given configuration.

Although the invention is of somewhat general utility along the lines indicated abovc.-it is particularly applicable to the die cutting of stacks ofpaper sheets and is described below in connection with such a die cutting press.

in the past, although presses. of this latter type have been somewhatimproved, they nevertheless have required manual positioning ofthe die. cutting blank on the stack of sheets to enable the blanks to be cut item the stack ofsheets. Thus, according to one known, type of die cutting press of this type, the operator is required to manually position a die on a stack of sheets, whereupon the press then can be actuatedto advance a table which carriesthisstack of sheets with the die thereon to a, location wherethe die is positioned'beneatharam, andthen theram descendstodrivethe diethroughthe stack of sheets, whereupon'the ram moves back up to its rest position and the table returns to its starting position so that the operator can again positionthe dieon. the stack of. sheets after removing from the interior of, the diethe blankswhieh have been cut fromthe stack of. sheets. H

These.operationsrequirea very skillful operator. to properly position the die before'eachoperating cycle is initiated, and-in addition-the: die ltsclflis .quiteheavy. so that the. operations are exheultingto theoperator-oflthe machine. Theresults which" can be achieved ;with,a;die;press ofthis type depend to a very large measure on theskill otgthe operator both withrespect to the mosteconomicalguseoi'rthe sheets from which the blanks arecutandtwithwrespecttto the rateatewhich theblanks are Pro d-g.

A-primaryobject otthepresent invention is .to provide a die pressot'tthis typetwithtutructure enabling it automatically to carry out a,plurslityofzcyeles ofoperation so that'astackof wan beautomatically,operatedmponto haveblanltsrcutl therefrom.

constantattendanceupon-the machines Yetanothet Object.oflthelpresentinventionzis to providesa machin whichldoesnot-requirean-operator topositionadie manually soqthatsthe.energy exerted by the :operator is very greatly reduced:whileatrthetsame time the safety of the press 75 r is greatly, increased-i.

Yet another objectof th'e.presentinverition is to provide a press of the above type which is'capable of automatically ejecting'from the'interior ofadiea' stack of bl'anks which have been cut from ast'ackof sheets.

Also, it is an object "of the present invention to provide a press of the above type which'canoperate with far greater accuracy then conventional machinesso a's'to produce stacks of blanks which -will have far more uniform dimensions from the top to the bottom of the stack. The objects of the present invention also include a press of the above type whichc'a'n be electrically programmed automatically to carryout a series of operating cycles of the type mentioned above, withthe electrical programming being extremely flexible so that any'desii'ed sequence of operating'cycles can be carried out.

Furthermore, the objects of the present invention include the provision of a press ofthe above type which, while it is capable of being electrically programmed, is also provided with a number of safety features which will automatically prevent operations which might either injure the machine or the operator.

7 Furthermore, it is an object of the present invention to provide a machine which can receive its operating signals from any type of known signalling structure, such as manually adjustable signalling potentiometers, punched tape or magnetic tape readers, punched card readers, etc.

it is furthermore an object of the present invention to provide a machine of the above type which, it" for any reason F thereof located beneath" clamps which clamp the sheets to a table which'supports' the sheets.

. Considering the present invention generally, the structure thereof includes a table which carries a stack of sheets which are to be cut. This table is supported by a suitable support means for movement backa'ndforthalong a'first axis. Aram is supportedby this support means for movement along a working stroke downwardly toward the table and then along a retum'strokeupwardly: away from the table back to a rest position ofthe ram, andthis ram*carriesacrosshead which is supported by the ram'fo'r'movement'relative thereto along a second axis which isperpendicul'ar'to the first'axis alongwhich the table moves; This crosshe'ad'ofthe' invention carries a'die carrier which is mounted on'the crosshead for angular movement aboutathirdaxis which'isperpendicular to the first and second axes; so that the die carriercanangularlyposition a die with respect to the crossh'e'ad and the-table. A plurality of elec tric motors drive transmissions which are respectively connected operatively to th'e'table, head; and die carrier for positioning the latter with respect to the=' fi'r'st.' second, and third axes; respectively, and a plurality of feedback potentiometers are driven by these-"electric motors so "as to provide signals which indicate-thepositibns of the table, head and die carrier respectively;

A plurality.- of signal* 'potentiometer sets" are provided for respectively earrying'out aseries ofoperating cycles, and each set i of signal 'potenti'ometers includes manuallyadjustable potentiometersformanually selectingkloc'ations' ofthe table,

head and diecarrier with res'pect to theti'rst; second, and third axes. Anfelectrical' means 'is electrically connectedwith the signalpotentiometers,with the'feedback 'potentiometers, and 1 with-the electric'motors for operatingthe lattrfirst to change the positions of the-table;headianddie carrir until the feed-' back potentiomet'er's provide "signals which match those of a given set of 'signal'potentiorneteri whereupon'this electrical means operates the motors to maintain these positions of the table, head and die carrier where the signals from the feedback potentiometers match those from the signal potentiometers, and then in accordance with the invention a circuit will be closed automatically to initiate the downward movement of the ram along its working stroke so that the die will cut through the stack of sheets, and then the ram will return upwardly to its initial position. The die carrier carries, within a die which is carried thereby, an ejector means which is also automatically actuated to eject, from the interior of the die, blanks which have been cut thereby from a stack of sheets, and the return of the ram upwardly towards its rest position automatically actuates a sequencing means which automatically introduces the signals of the set of signal potentiometers of the next cycle, so that the next-following operating cycle will be automatically initiated.

The invention is illustrated, by way of example, in the accompanying drawings which form part of the application and in which:

FIG. 1 is a fragmentary perspective illustration of one possible die cutting press according to the invention;

FIG. 2 is a schematic illustration of the manner in which various parts of the press are controlled;

FIG. 3 is a top plan view of the die cutting press of the invention;

FIG. 4 is a longitudinal section of the press taken along line 4-4 of FIG. 3 in the direction of the arrows;

FIG. 5 is a transverse sectional elevation of the press of FIG. 3 taken along line 5-5 of FIG. 3 in the direction of the arrows;

FIG. 6 is a sectional elevation of the crosshead and die-carrying structure as well as of the ejector means of the invention;

FIG. 7 is a fragmentary sectional elevation showing the details of the clamping structure of the invention for clamping a stack of sheets to a table;

FIG. 8 is a fragmentary section diagrammatically illustrating the manner in which one type of die cuts through a stack of sheets;

FIG. 9 is a schematic sectional elevation fragmentarily illustrating the manner in which another type of die cuts through the stack of sheets;

FIG. 10 represents the sequence of operating cycles during which blanks can be cut from a stack of sheets;

FIG. 11A is an illustration of one possible arrangement of a series of sets of manually adjustable signal means for introducing selected signals so as to carry out automatically a series of selected operation cycles;

FIG. 118 shows in detail one of the sets of manually adjustable signal potentiometers forming one of the plurality of units of FIG. 1 1A;

FIG. 12 represents a panel available to the operator on a console which also carries the structure of FIG. A, the structure of FIG. 12 being provided to enable theoperator to set the machine up to carry out a selected sequence of operating cycles;

FIG. 13 is a schematic representation of the sequence of operations during each operating cycle;

FIG. 14A is a schematic illustration of the sequencing structure of the invention which automatically Initiates an operating cycle upon completion of the previous operating cycles;

FIG. 14B is also a schematic representation of the sequencing structure of the invention, FIG. 14B showing details of the structure which are not apparent from FIG. 14A;

FIG. 15 is an electrical wiring diagram of the structure which carries out the series of operations represented in FIG. 13, FIG. 15 showing electrically the structure which is indicated schematically in FIG. 2;

FIG. 16 is a wiring diagram of the structure for initiating a cutting cycle when the movable parts of the machine have reached their selected positions during a given operating cycle, FIG. 16 also showing various safety switches included in the circuit;

FIG. 17 illustrates the manner in which the circuits of FIGS. 15 and 16 are combined;

FIG. 18 is a schematic illustration of the hydraulic structure of the press of the invention, FIG. 18 also schematically illustrating how this hydraulic structure is electrically actuated by the electrical structure of the invention;

FIG. 19 is a schematic plan view illustrating a somewhat different clamping arrangement as well as showing various safety features and indicating how the table is unloaded upon completion of a series of operating cycles on a given stack of sheets; and

FIG. 20 is a wiring diagram illustrating how it is possible to release a selected clamp to enable cutting of the stack at a part thereof situated beneath a clamp.

A general understanding of the press of the invention is provided by FIG. 1. As may be seen by FIG. 1, the structure includes a suitable support means 30 on which a table 32 is guided for longitudinal movement back and forth along a first axis which extends longitudinally of the machine. The table 32 carries a stack of sheets 34 which are to be cut into blanks of predetermined configuration, and the stack of sheets 34 is releasably maintained in position on the table 32 by the plurality of releasable clamping means 36, two such clamping means being shown in the illustration example.

A ram 38 is supported by the support means 30 for movement downwardly along a working stroke and upwardly back to a rest position such as that illustrated in FIG. I, and this ram may be mounted in a known way on cornerposts 40 connected to suitable pistons which slide in cylinders and which are hydraulically actuated so as to provide in this way the high pressure required for the operation of the press. The manner in which the ram 38 is moved along its working and return strokes forms no part of the present invention, and this structure may, for example, take the form of the structure shown in U.S. Pat. No. 2,815,810, including not only the structure for moving the ram 38 up and down but also the structure for equalizing the movement of the ram when operations take place beneath one or the other of the ends thereof.

A crosshead 42 is carried by the ram 38 for movement transversely with respect to the table 32, along a second axis perpendicular to the first axis along which the table 32 moves, and this crosshead 42 carries a die carrier 44 which is mounted on the head 42 for rotary movement about a third axis which is perpendicular to the axes along which the table 32 and the head 42 are respectively movable, this third axis of course being vertical and extending parallel to the ram-supporting posts 40. The die carrier 44 carries a die 46 which will be forced down through the stack of sheets 34 during each working stroke of the ram 38, and this carrier 44 in addition carries within the die 46, an ejector means which is referred to below.

The support means 30 carries an electric motor which is operatively connected to the table 32 for moving the latter back and forth along the first axis referred to above, and the ram 38 carries a motor 48 which is visible in FIG. 1 and which is operatively connected to the head 42 for moving the latter back and forth along the second axis which is transverse to the axis of movement of the table 32. The head 42 itself carries a motor which is operatively connected to the die carrier 44 for turning the latter about the third, vertical axis referred to above.

Finally, there is diagrammatically indicated in FIG. 1 an electrical connection 50 between the clamps 36 and a grounded part of the machine so that, in a manner which is described in greater detail below, if the die 46 should engage one of the clamp means 36 the machine will automatically reverse itself so as to prevent injury to the machine as well as to the operator.

Referring now to FIG. 2, it will be seen that the motor 48, which is carried by the ram 38, is shown as rotating a screw 52 through the transmission 54 illustrated schematically in FIG. 2, and this screw 52 is supported by the ram 38 for rotary movement but is prevented from moving axially. The screw 52 passes through the crosshead 42 and is threadedly connected therewith so as to advance the crosshead along the second,

ment transverselyof thepress. The transmission 54 also serves to transmit rotationof tli'ejs crew 52 to a feedback potentiometer 58 which sends a signal to an amplifier 60 which is electrically connected with the motor 48 to control the latter in a manner described below, and, as is schematically illustrated in H6. 2, the amplifier 60 is electrically connected with a signal potentiometer 62 which is carried by a suitable console 64 and which canber'nanually set by the operator so as to automatically provide a selected position of the crosshead 42.

As is also schematically illustrated'in FIG. 2, a motor 66 is connected througha transmission 68 to the table 32 for advancing the latter along the first, longitudinal axis, in the direction of arrow.70, so that in combination with the movement of the head 42 along the second, transverse axis in the direction of arrow 72, the head 42 and the table 32 can be oriented relative to each other. The transmission 68 rotates a screw 74 which is threaded through a nut carried by the table 32 at its underside so that the table 32 will be advanced back and forth, suitable guides, such as the guides 77 shown in FIG. 1, being provided to guide the table. The transmission 68 transmits rotation of the screw 74 to a feedback potentiometer 76 which is electrically connected to an amplifier 78, electricallyconnected not only with the motor 66 but also with a manually operable signal potentiometer 80. n

t The head 42 itself-serves to support an electric motor82 which through the transmission 84 drives a worm 86 which meshes with a wormwheel 88 mounted on a shaft 90 which is fixed to the die carrier 44 so that the latter will turn with the worm wheel 88 in response to operation of the motor 82, and the transmission 84transmits rotation of the worm 86 to a feedback potentiometer which is electrically connected to an amplifier 94whichin turn is electrically connected to a third manually operable signal potentiometer 96. The signalling assembly carried by the console 64 includes in additionto the manually

operable signal potentiometers

62, 80 and 96, a manually operable switch 98 which can be used to render the entire signalling system operative or can be used to render it imperative Considering the signalling potentiometer 80, for example,

, the operator canmanually adjust this potentiometer so as to provide with it a signal which will correspond to a selected position of the table 32 along the longitudinal axis. This signal from the potentiometer 80 will be impressed upon the amplifior 78. At the same time, the feedback potentiometer '76 impresses on the amplifier." a signal which is determined by the actual position of the table 32 along its axis of movement. As long as the signals from the potentiometer 80 and the feedback potentiometer 76 are different, the amplifier will detect the difference in potential. These signals have opposed polarities, and as long as the amplifier 78 detects the opposed polarities of the signals from the

Potentiometers

80 and 76, the servomotor 66 will rotate its shaft so as to rotate the screw '74 through the transmission 68. Therefore the signal from the feedback potentiometer 76, which is also driven from the transmission 68,.wili change, so that the amplifier 78 will continuously be influenced. by the difference between the opposed polarltles of the

potentiometers

80 and 76. This operation continues until the polarities of the

potentiometers

80 and 76 oppose each other equally. The amplifier will still maintain the motor 66 energized but its shah will not turn and the table 32 will remain stationary at the position which has been automatically determined in this way by the manual setting of the potentiometer 80.

in the same way the manual setting of the potentiometer 62 acts through the amplifier 60 on the motor 48 to cause the latter to drive the crosshead42until the signal from the feedback potentiometer exactly equals and opposes that from the potentiometer v62. Then the shaft of the energized motor 58 willaiso stop turning so as to maintain the crosshead 42 at the position which has been determined by the setting of the potentiometer 62. Y

Finally, the signal from the potentiometer 96 acts through the amplifier 94 on the motor 82 to keep the latter rotating its shaft until'the potentiometer 92 provides a signal which exactly equals and opposes that of the potentiometer 96, and this will result in providing for the die carrier 44 an angular position determined by the manual setting of the potentiometer 96. For a purpose which is described below the shaft together with the die carrier 44are capable of being turned in one direction or the other through an angle of approximately 500.

Referring now to FIG. 3, there is shown more clearly therein the manner in which the guide rods 56 are carried by the ends of the ram 38 so as to guide the crosshead 42, and of course FIG. 3 also shows the screw 52 which is threaded through the crosshead 42 for advancing the latter transversely of the press. Furthermore, FIG. 3 shoes the arrangement of the various motors, the motor 82 being shown carried by the crosshead 42. The motor 66 which is operatively connected to the table 32 is situated beneath the latter and is carried by a suitable bracket which is carried by and forms part of the support means 30, and furthermore FIG. 3 shows a nut 100 fixed to the underside of the table 32. The screw 74 extends threadedly through the nut 100 so that in this way the table is advanced or retracted.

it is to be noted that the table 32 is shown in FIG. 3 in a ready" position form which it moves rearwardly to a location beneath the ram 38, and after the series of operating cycles described below have taken place the table 32 returns to the ready position indicated in FlG. 3.

Furthermore, as will be apparent from the description below limiting switches are provided to automatically open the electrical circuit referred to below so as to limit the extent of movement of the table and the crosshead, and the limiting switches 102 which limit the movement of the crosshead 42, so that it will not strike against the ends of the ram 38, for example, are clearly indicated in FIG. 3. These are normally closed switches which upon being engaged by the crosshead will open so as to open a circuit referred to below. in the same way the support means 30 carries limit switches to limit the forward and rearward movement of the table 32. Furthermore, in order to prevent operation of the ram 38 when the table is in the ready position indicated in FIG. 3, the table car ries a cam, which is not shown in FlG. 3, and this can maintains a safety switch in an open position as long as the table is in the position of FIG. 3, so that in this way the circuit is maintained open and the ram 38 cannot be operated until the table moves rearwardly from the position indicated in FIG. 3.

Also shown in FIG. 3 are rollers 104 carried by the table 32 just in front of a stack-carrying portion of the table 32, so that a sheet 106, referred to below and carrying the stack of sheets 34, can be removed from the forward, stack-carrying portion of table 32 and guided along the rollers 104 onto an unloading table at which the blanks can be collected while another sheet 106 is placed on the table with a new stack of sheets 34 to be cut. in this way a new series of operating cycles can be carried out while the operator collects the blanks on the unloading table.

The rollers 104 are also apparent in FIG. 4 which more clearly illustrates the manner in which the screw 74 cooperates with the nut 100 which is fixed to the underside of the table 32. As is clearly illustrated in FIG. 4, the table includes a spacer board 108 to the top face of which is fixed a replaceable backup member 110 which can be made of Masonite, for example. The spacer 108 as well as the table 32 itself can be made of plywood, for example, sheets of plywood having a thickness of three-fourth inch each. The intermediate sheet 106 which is interposed between the table assembly and the stack of sheets 34 is resilient compressible sheet of a suitable rubber or the like, and it is this intermediate sheet 106 which is removed after the series of operating cycles on each stack 34 has been completed, this sheet 106 together with the stack 34, which has been cut through by the die, rolling along Referring now to FIG. 5, it will be seen that the hydraulic structure 116 which acts on the posts 40 to reciprocate the ram 38 is schematically indicated. Also FIG. clearly shows the limit switches 102 for the crosshead 42, as well as the die 46 which is carried by the rotary die carrier 44. FIG. 5 also shows the stack of sheets 34 in its elevational position with respect to the die 46. The machine is designed so that the die 46 need only be raised a few inches above the stack of sheets. Thus, the stroke of the ram 38 is not very long and the operations can be carried out in a minimum of time.

Referring to FIG. 6, several important features of the invention are illustrated therein. FIG. 6 clearly illustrates how the head 42 is situated beneath the ram 38 for movement along the guide rods 56, and in addition FIG. 6 shows how the screw 52 is threaded through a nut 117 which is carried by the crosshead 42 in alignment with an opening through which the screw 52 extends. The motor 82 is mounted on the rear wall of the crosshead 42 and is not visible in FIG. 6, and this motor of course drives the worm 86 which meshes with the worm wheel 88, as indicated in FIG. 6. The worm wheel 88 is fixed to a hollow shaft 118 which in its interior forms a hydraulic cylinder, and the shaft 118 receives at its top end in nonfluidtight manner, a plug 120 which allows a constant flow of lubricant to the interior of crosshead 42 to take place. The shaft 118 turns in a bearing 122 carried by the bottom wall of the crosshead and extending through a central opening thereof, and this bearing 122 is formed with a pair of bores which are respectively aligned with conduits 124 which communicate through bores 126 in the crosshead 42 with the aligned bores of the bearing 122, so that hydraulic fluid can enter into annular grooves 128 which are formed in the exterior of the shaft 118 and which are respectively at the elevation of the bores 126. The rotary shaft 118 is threaded at its bottom end and carries a nut 130 which serves to mount on the bottom of the shaft 118, adjacent a flange 133 thereof, the die carrier 44. A shear pin 132 is situated in aligned bores of flange 133 and die carrier 44, and in this way the die carrier 44 is compelled to turn with the hollow shaft 118 which of course is fixed to the worm wheel 88 so that in this way the die carrier 44 is turned. If shear pin 132 breaks, carrier 44 will be free to rotate.

The die carrier 44 has a plate 134 fixed to its underside by the screws 136 which extend through keyhole slots 137 of the plate 134 into threaded bores of the carrier plate 44, these keyhole slots providing quick mounting of plate 134 on carrier 44, and this plate 134 has countersunk openings through which screws 138 extend into threaded bores which extend into the die 46 from the top edge thereof, so that in this way the die 46 is fixed to the plate 134 before the latter is joined to the die carrier 44. Of course, the heads of the screws 138 are received in the countersunk bores which extend through the plate 134 so that the top surface of the plate 134 can bear directly against the bottom surface of the plate 44. The feature of providing this arrangement according to which the die 46 can be removed by shifting plate 134 to more keyhole slots 137 with respect to the screws 136 is of considerable significance, since in this way the operator need not place his hands beneath the die 46 during attachment of the latter to the diecarricr.

The structure of the invention includes an ejector means 140 capable of ejecting from the interior of the die 46 the blanks which have been cut thereby and which are received in its interior. This ejector means 140 includes the lower plate 142 which is vulcanized or otherwise bonded to a metal plate 144 which is formed with a central bore. Although plate 142 may be resilient, resiliency of plate 142 is not essential. A nut 146 is threaded onto the bottom threaded end of a piston rod 148 which is fixed to and extends from a piston 150 which is slidable in the interior of the hollow shaft 118. Removing nut 146

permits plates

142 and 144 to be removed. The upper annular groove 128 of FIG. 6 is always maintained at an elevation higher then the piston 150 because the bottom reduced end of the plug 120 extends below this upper groove 128 and thus prevents the piston 150 from rising to the elevation of the upper groove 128. This groove 128 communicates through a bore in the shaft 118 with the interior portion thereof whicl: surrounds the reduced bottom end of the plug 120. The lower annular groove 126 communicates through a downwardly directed bore 152, formed in the shaft 118, with the interior lower portion of the shaft 118 just below the reduced upper end ofthe circular member 154 thereof which fluidtightly surrounds and guides the piston rod 148, and which prevents piston 150 from reaching the bottom end of bore 152. Thus, when fluid under pressure is introduced through the upper conduit 124 the piston rod 148 will be lowered to cause the ejector means to eject blanks from the interior of the die 46, while at the same time the lower conduit 124 will of course be at low pressure, and then suitable valves are reversed so that the pressure in the upper conduit 124 drops and fluid under pressure is introduced through the lower conduit 124 so as to extend beneath the piston and raise the latter to the illustrated position, so that in this way the ejector means 140 is retracted.

Of course, the conduits 124 have flexible portions in the form of suitable hoses which communicate with the remainder of the hydraulic circuit, so that in this way the flexible hoses will permit the crosshead 42 to move transversely across the press.

The details of the clamping means 36 are illustrated in FIG. 7. Thus, it will be seen that the stack of sheets 34 is placed against a stop bar portion 156 which is fixed to and extends upwardly from a metal plate 158 which is fixed to the table 32 and which carries the stop bar 156 against which the paper is placed. This stop bar 156 extends upwardly through a slot which is formed in a front end portion 160 of the clamping means 36, this portion 160 directly engaging the stack as indicated in FIG. 7. A pair of upstanding support members 162 are carried by and stand upwardly from the plate 158, and these members serve to pivotally support flanges 164 of the clamp means 36 for turning movement about a common horizontal axis provided by the pivots 166. In addition the supports 162 pivotally carry a ring 168 which fixedly surrounds and carries a hydraulic cylinder 170 provided with hydraulic fluid through a conduit 172. A piston in the interior of the cylinder 170 is connected to a piston rod 174 which engages a block 176 fixed to a rear wall 178 of the clamp means 36, so that the latter turns in response to movement of piston rod 174 relative to cylinder 170. A spring 180 is fixed at one end to the base 158 and at its opposite end to a pin 182 carried by the rear wall 178 of the clamp so as to urge the clamp to the inoperative position where portion 160 is spaced from stack 134, when the piston rod 174 is retracted into the cylinder 170. The entire cylinder 170 turns automatically during axial movement of piston rod 174.

It is to be noted that in its inoperative position the front tip portion 160 of the clamp is located much closer to the plane of the stop bar 156, so that in this way when the clamp is placed in its nonclamping position it is capable of exposing a portion of the stack of sheets 34 which is situated beneath the front clamping portion 160 when the clamp means 36 is in its operative position shown in FIG. 7.

The top of the clamp carries a relatively thick resilient layer of relatively soft, yieldable, resilient material, such as foam rubber or the like and there is cemented or otherwise fixed to the upper surface of this layer 184 a film or thin sheet 186 of metallic, electrically conductive material which may be connected by a conductor 188 to the base portion 158 which is also electrically conductive. FIG. 7 diagrammatically indicates in dot-dash lines a part of the die 46 in engagement with the conductive exterior layer 186 at the top of the resilient layer 184. As may be seen from FIG. 7, the base plate portion 158 is fixed by a bolt 190 to the table 32, and this slot is in turn connected by a wire 192 to a suitable ground connection. There is an unillustrated connection between the wire 192 and the metallic supporting frame 30 which serves as a ground.

Referring to FIG. 7, it will be seen that the wire 192 is connected with a solenoid 194 which through a suitable circuit, such as the ground circuit referred to above, is connected to the die 46. The layer 186, which is electrically conductive, is shownin FIG. 7 carried by theresilient layer l84,and the wire 188 connecting the conductive layer 186 with the base 158 is also indicated in FIG. 7; Of course, if it should happen that the die46 engages the conductive layer 186, on the one hand the resilient layer- 184will be capable of being compressed so as to prevent injury to the clamp and on the other hand the solenoid 194 will be immediately energized so as to reverse the movement of the die '46, as will be apparent from the description below.

Of course it is to beunderstood that the illustration in FIG. 7 is schematic.v There is ,nosource of current as indicated in this diagram. Instead the circuit is grounded so that when the die 46engages the layer. 186 the circuit will be completed through the solenoid 194 which has a cutting reversing function. The diagrammatic connection 50in FIG. 1 indicates the grounding of the conductive layer of the clamping means 36.

Referring now to FIG. 8, the manner in which the die 46 cuts through the stack of sheets 34 is indicated. It will be seen that the die 46 has inner. and outer surfaces which taper toward each other to provide thecutting edge 194, and this cutting edge can extend through a slight distance into the resilient material 106 without injuring the latter excessively so that it will; have a long life. Furthermore, because of the resiliency of the thin sheet 106, it provides a somewhat floating" support for the stack 34 which has been found to greatly improve the cutting operations. As may be seen from FIG. 8, because of the curvature of. the inner and outer side surfaces of the die 46, particularly where they taper to form the cutting edge 194, the blanks which are cut from the stack 34 bulge upwardly in the interior of the die, and if the ejector means presses against the stack 34 simultaneously with the cutting thereof, the blanks would have a tendency to push outwardly against the wall ofthe die 46. In order to prevent such an operation the ejector means I40 is maintained in its inoperative position while the die 46 descends through the stack of sheets 34. At the end of the cutting, when the die has about the position indicated in FIG. 8, the structure acts to automatically actuate the ejector means 140 which pushes the blanks cut from the stack out of the interior of the die 46 simultaneously with the upward movement thereof with the ram 38.

With the arrangement as shown in FIG. 8, there will be some discrepancy in the dimensions of the blanks from the top to the bottom of the stack, and although the support provided by the resilient sheet 106 will to some extent cut down on this discrepancy, nevertheless an arrangement as shown in FIG. 9 will provide a far more accurate series of blanks in each stack of blanks cut from the stack of sheets 34. As may be seen from FIG. 9, the die 46 is replaced by a die 196 which has an inner side surface which extends parallel to the direction of the movement of the die during its cutting stroke all the way down to the cutting edge 198 of the die 196. Only the exterior surface of the die tapers towards the cutting edge 198. With this construction the ejector means 140 is actuated so as to exert a steady pressure on the stack 34 simultaneously with the cutting thereof by the die I96, and with this arrangement a far more accurate stack'of blanks will be achieved, which is to say the blanks will have far more uniform dimensions from the top to the bottom of the stack of blanks.

FIG. 10 diagrammatically illustrates a stack of sheets 34 clampedby the pair of clamping means 36. Note that FIG. 10

shows the slotted front ends of the clamping means through I which the stop bars 156 extend. The bases 158 are fixed to the table in the manner described above. In the illustrated example the stack of sheets are placed against the front and right stop bars 156 inasmuch as the series of operating cycles progress generally from the rear left comer of the stack 34, as viewed in FIG. 10, toward the front, right comer thereof.

The outline of the cutting edge of the die 46 or 196 is indicated in FIG. 10. The die will be successively positioned through the fifteen different positions indicated in FIG. 10 with the sequence which is also indicated inFIG. 10 in order to cut the blanks from the stack 34. When the die is in position No. l, as shown in FIG. 10, and passes down through the stack of sheets 34, this stack will break out" at the regions a, which is desirable and which indicates that the first position has not been displaced inwardly too far from the side edges of the sheets 34 at the upper left corner thereof, as viewed in FIG. 10. After the operating cycle at position No. 1 has been completed, the machine will, in a manner described below, automatically position the die and the stack 34 with respect to each other in the position No. 2 indicated in FIG. 10; and then during the next cutting stroke there will be a "break out" at the regions b. When the third operating cycle takes place, the die has the position No. 3 indicated in FIG. 10, and a break out" occurs at the region 0. During the next following cycle the die has position No. 4 as shown in FIG. I0, and "break out occurs at the region d. In this way the cutting of the stacks of blanks from the stacks of sheets 34 continues with the sequence indicated in FIG. 10.

The sheets 343 are placed against the stop bars 156 because the sequence of operating cycles progresses toward the front right hand comer of the stack 34 indicated in FIG. 10. However, this is not essential and the clamps may be positioned in engagement with the rear edge of the stack 34 and also with the right edge thereof, as shown for the right clamp 36 in FIG. 10, in the case where it is desired for the sequence of operating cycles to progress from the front left toward the rear right comer of the stacks of FIG. 10. In this case the sequence of operating cycles would be a mirror image of that shown in FIG. 10. Furthermore, more than two clamps may be provided, if desired, engaging more than two edges of the stack 34.

It is to be noted, in addition, that while the front clamp 36 of FIG. 10 is shown situated adjacent the No. 9 operating cycle, while the right clamp is shown situated between the No. 14 and No. 15 operating cycles, if desired, in order to make the most economical use of the stack of sheets 34, the positions of the die may be situated directly beneath the part of the clamp 36 which engages the stack. When the operations are to be performed at the area beneath the front end of the clamp, the latter is rendered inactive to return to its inoperative position so as to provide a space for the die to descend through the stack. For example, if the right clamping means 36 of FIG. 10 were shifted to the rear, it would cover the position No. I4 indicated in FIG. 10, and in this case it would only be necessary to raise the clamping member to its nonclamping position so as to give the die access to the position No. I4.

The sequence of operating cycles indicated in FIG. 10 is capable of being automatically carried out with the use of a panel such as that indicated in FIG. 11A. This panel has a plurality of sets 200 of manually adjustable signalling potentiometers which correspond to those described above in connection with FIG. 2, and it will be noted that each unit or set 200 includes a switch 98 for rendering the unit inoperative or operative. The several sets of manually operable signalling potentiometers 200 are capable of being manually positioned according to the sequence indicated in FIG. 10, and it is to be noted that the number of sets 200 is greater than the i5 positions shown in FIG. 10, so that the panel of FIG. 11A can be used for a relatively large number of positions. Actually, there is no limit to the number of positions which can be provided with the structure of the invention, and in addition it is to be noted that it is not necessary to use all of the positions since a given series of cycles can be completed with only part of the potentiometer sets 200 shown in FIG. 11A. Furthermore, as will be apparent from the description which follows, it is not essential to use the series of sets of signalling potentiometers 200 in sequence. Any desired set can be omitted from the operation and the structure will automatically advance to the next operative set of potentiometers 200, so that the arrangement of the invention is extremely flexible.

As may be seen from FIG. 113, each set of manually adjustable signaling potentiometers 200 has a manually turnable knob 202 carrying a suitable scale which indicates positions of the part of the machine which is to be adjusted. This knob has its scale cooperating with a vernier scale 204, as shown for the die angle potentiometer 96 in FIG. 11B, and in the same way the head-adjusting potentiometer 62 will cooperate with a vernier scale, and the same is true for the angular scales used with the manually adjustable signalling potentiometer 80 for providing a selected table position. Furthermore, FIG. 118 shows the switch 98 which is illustrated in the on position, but which can be displaced to the "off position if desired. The numerals indicating the different positions are located on lamps 203 which when energized indicate that switch 98 is on and that therefore the set of potentiometers are operative. Lamp 203 goes "on" only when the particular signal station is in control of the servos. Turning switch 98 "off" makes the control bypass that particular position the lamp however goes "on" momentarily as the stepping switch sweeps past.

The particular set of potentiometers 200shown in FIG. 11B

. is that which corresponds to positions No. 2 of FIG. 11A, but

it is to be understood that the entire series of sets 200 of FIG. 11A are constructed identically with that shown in FIG. 118. When the switch 98 is in the "on" position, the control will stop at that position to permit the potentiometers to control the servos. As was indicated above any set 200 can be rendered inoperative by displacing the switch 98 thereof to the "off" position, and then the sequencing structure will simply progress to the next set of potentiometers 200 which is in the "on position. Furthermore, as will be apparent from the description below, these sets of potentiometers or units 200 can be provided with an additional switch capable of being connected into the sequencing circuit for rendering one or more of the clamps 36 inoperative if the operating cycle is at the edge of the stack where it is necessary to cause the clamp to be raised away from the stack to give the die access to the stack, as was discussed above.

FIG. 12 indicates a panel of controls also accessible to the operator on the console 64 of FIG. 2. The panel of FIG. 11A may be located on the upper inclined portion of the console while the panel shown in FIG. 12 may be located on the front inclined part of the console just beneath the inclined front upper portion thereof. This panel 206, which is indicated in FIG. 12 is used in order to set the press up so as to carry out a sequence of operations such as that indicated in FIG. 10. When the operator is setting up any one of the Operating cycles indicated in FIG. 10, the adjustable potentiometers 200 corresponding to that operating cycle will be manually set, and the panel 206 will be used to operate the machine during this setup period.

There is shown at the upper central portion of the panel 206 a manually operable potentiometer 208 which is capable of moving the head 42 simply by manual actuation of the potentiometers 208, and in this way the operator can conveniently position the head to have a die mounted on or removed from the die carrier in the ready position.

At the left of the manually operable potentiometer 208 are shown shrinking potentiometers capable of adjusting the series of positions such as those shown in FIG. 10. It will be noted that these

potentiometers

210 and 212 are designated head shrink left and head shrink right. The setting up of the various operating cycles indicated in FIG. may result in crowding of the several positions of the die on the stack too much toward the right edge or too much toward the left edge of the sheet, and the

shrink potentiometers

210 and 212 are respectively available to the operator for changing the lateral distributions of the positions indicated in FIG. 10, for example. either so as to narrow or widen the spaces between the several positions of the die toward the left or toward the right depending upon the operation of the

potentiometers

210 and 212.

Of course, it may happen that the various positions such as those indicated in FIG. 10, become crowded too near to the front of the stack, or too near to the rear thereof, as the layout progresses, and in this case the

shrink potentiometers

214 and 216 are available to the operator, the potentiometer 214 being a shrink potentiometer applied to the table controls for crowding the positions in toward each other from the front to the rear of the stack, whereas the potentiometer 216 is available for spreading the positions out between the front and rear ends of the stack. The various positions of the successive operating cycles are in an electrical circuit in which these positions are connected in parallel with each other so that the adjustment of any of the shrink potentiometers is equally distributed among the several positions, in a manner which will be apparent from the description below. In this way one can achieve an equal spreading of the die positions indicated in FIG. 10 either laterally or longitudinally of the stack of sheets.

The central portion of the panel 206 carries a lamp 218 which is illuminated to indicate that the apparatus is ready for operation, and a master switch is available at the side of the machine for turning the entire apparatus on or off. A lamp 220 indicates when the cutting is on.

During the manual setting up of the machine it is desirable to hold the machine in a given position preventing it from advancing to the next position while adjustments are being made on the set of potentiometers 200 which correspond to the given position, and for this purpose there is available to the operator a selector switch control 222 which when turned by the operator will extinguish a lamp 224 to indicate to the operator that the press will not advance to the next position. When it is desired to advance to the next position the operator can press the push button switch 226 available at the panel 206, and now adjustments of the set of potentiometers 200 at the next position can take place.

Of course, these setting-up operations will not take place with an entire stack of sheets. Only a single sheet previously marked with the die positions, need be placed on the support 106 during the setup operation, and the ram is maintained in a low position with the die only slightly above the sheet to match the die positions to those marked on the setup sheet. Manual switch 230 is placed by the operator in the off position indicated on the panel to prevent cutting during the setup and lamp 220 will be extinguished. The recycling switch 228 can be actuated to sequence the machine back to its starting position.

In this way the set of controls provided at the panel 206 enable the operator to set the machine up so as to carry out a preselected series of operating cycles such as, for example, those indicated in FIG. 10.

FIG. 13 schematically illustrates the operations which take place at each operating cycle. The set of adjustable signalling potentiometers 200, indicated at the lower left of FIG. 13, provides a command signal which is received by the amplifier 232, which corresponds to any of the

amplifiers

60, 78 and 94 shown in FIG. 2. The amplifier 232 transmits the signal to the ,motor 234, which again may be any of the motor shown in FIG. 2, and this motor drives a transmission 236 such as any of the transmissions referred to above which in turn operates the feedback potentiometer 238 which feeds an error signal 240 back to a part 242 of the amplifier 232 which provides a summation of the feedback and command signals. As was indicated above, these signals will have opposed polarities, so that the motor 234 will continue to operate until the signals are exactly equal to each other. When the transmission 236 has placed the structure in the function position 244, as shown in FIG. 13, the shaft of the motor 234 will of course have stopped turning, and this will, in a manner described below, initiate the function 246 which is the cutting through stack at the position 244. When the function 246 is completed it will automatically advance the machine to the next set of signalling potentiometers 200, as indicated in FIG. 13, and then this cycle of operations is repeated for the next position.

The sequencing of the press from one operating cycle to the next is carried out with a circuit having the structure shown diagrammatically in FIG. 14A. This is a DC circuit which may be provided with 24 volts, for example, and FIG. 14A shows the switch 98 of each of the sets of units 200. The switch 98 is shown in FIG. 14A in its open position, and of course it can be manually closed for any set of potentiometers 200 which is to be operative; Furthermorep the circuit shows the recycling switch 228 which is a'normally closed switch.

FIG. 14A showsa stepping switchassembly 248 including the ratchet wheel 250which steps the switch bar 252 from one position to the next during each successive actuation of the solenoid 254 of the assembly248. This stepping switch carries out one step at a time, with an interruption, and in the event thateither the switch98 or the recycling switch 228 is open,

the interrupter portion of the solenoid 254 will be bypassed and thus the stepping switch assembly 248 will skip the particular position. Thus, the operation of the recycling switch will have the same effect as if a selected operating position is to be bypassed, and in this way by-actuating the position advance switch 226 on the panel the press can be advanced to a selected position or by actuating the recycling switch 228 the press can be'advanced back to the startingor ready position.

FIG. 14A also showsthe automatic holding switch 222 for maintaining the press ata given position. This switch is nor mally open and, when actuated by the operator, is closed so that the press will not advance to the next position until the switch 222 is again opened. t t

The switch226 for advancing the press to the next position is also indicated in FIG. MA. This switch is of course a normally closed'switch which at any time can be actuated by the operator so as-to open the circuit and thus cause an interruption in the solenoidcircuit for advancing the step switch 248 to the next position.

The circuit also includes a normally closed switch 256 which has an uppercontact arm 258 urged to its closedposition by a spring 260 and having a projection 262 in the path of movement of a cam 264 pivotally carried by one of the posts 40 which moves with the ram 38, this post being, for example, the front or rear post at the left side of the machine. A spring 266 urges thecam 264 to its outer position indicated in FIG. 14A, but at the same time this can turn in a clockwise direction about the pivot 268 into a-recess of the post 40 during downward movement of the ram 38 along its working stroke. Therefore, the switch-actuating am 264 can move downwardly past the free end 262 of the arm 258, but during upward return movement of the ram 38 as illustrated, the cam 264 will engage the end 262 of the arm 258 and open the switch 256 so that in this way also an automatic sequencing will be achieved. The opening of the switch 256 provides the interruption in the circuit which is necessary for the stepping switch 248 to become actuated for advancing the press to the next operating cycle.

The structure of FIG. 14A is shown, in some respects, in greater detail in FIG. 145. FIG. [4B shows a set 200 of manually operable potentiometers providing signals to determined position of the table, head and die, as indicated, and also the switches 98 are indicated. The stepping switch ratchet wheel 250 is schematically shown fixed with three arms 252A, 2523 and252C which respectively provide the controls for the crosshead. die angle, and table, in the example illustrated. Also, FIG. [4B shows how the

switches

222, 226 and 228 referred to above are connected into the circuit, as well as the solenoids 254A and 2543 which form part of the solenoid assembly of the stepping switch 248 for advancing the latter when there is an interruption in the circuit. As is apparent from FIG. 148, not only will the

several arms

252A, 2528, 252C beadvanced along the contacts corresponding to the several positions, as indicated, but before the series of operating cycles are initiated, these arms are in a starting position provided by the contacts 270a, 270b, 2700 and this is the position of the stepping switch when the table is in the ready position shown in FIG. 3. Once the machine is set up or once a new stack is in position to have performed thereon a sequence of operations which have already been performed on a previous stack, it is only necessary for the operator to actuate a manual cutting switch, referred to below, and the series of operating cycles will then take place automatically.

Referring now tdFlG. 15, the

contact arms

252A, 2528 and 252C of the stepping switch are diagrammatically indicated between the contacts I for position 1 and the contacts 2 for position 2, and it is to be understood that these will be sequenced by the above-described sequencing means of FIGS. 14A and 14B from one position to the next upon completion of a given operating cycle. FIG. 15 shows the

various amplifiers

60, 78 and 94 for the head, tableand die angle, respectively, as referred to above in connection with FIG. 2, and it will be seen that these are supplied with a three-phase alternating current and are connected to the

motors

48, 66 and 82 for the head, table, and die angle, in the manner illustrated in FIG. 15. These motors are standard three-phase AC motors with high slip rotors.

A source of power in the form of a 125 volt DC stabilized potential, for example, is impressed in the manner shown at the left of FIG. 15 into the circuit so as to be received by the

feedback potentiometers

58, 76 and 92 which are connected in parallel in the manner illustrated, and the sets of manually

adjustable potentiometers

62, and 96 for the first and second positions are indicated in FIG. 15.

Furthermore, FIG. 15 shows the shrinking

potentiometers

210 and 212 for distributing the positions laterally by distributing the resistance of these adjustable potentiometers between the several adjustable potentiometers 62 which are connected in parallel. In the same way the shrinking

poten tiometers

214 and 216 can be adjusted for distributing the resistances of these potentiometers equally among the parallelconnected adjustable potentiometers 80 which provide the signals which determine the positions of the table, so that in this way the spreading or shrinking of the operating positions between the front and rear edges of the stack can be controlled.

It is to be noted that FIG. 15 shows connected into the circuit a pair of

padding resistors

270, 272, these resistors being connected into the circuit of the parallel connected potentiometers 96 which give the signals for determining the position of the die angle. The shrinking potentiometers serve an additional function which is served by the

padding resistors

270, 272, and since there are no shrink potentiometers in the circuit of the signals for the die angle, the

padding resistors

270, 272 are included. Assuming that the DC stabilized voltage is impressed on the circuit as indicated, then of course the potential on the various circuits should be maintained at less than I25 volts. The reason for this is that during attainment of a given state of equilibrium the motors will not necessarily move up to the state of equilibriumand no further. They will sometimes overcorrect to a slight extent, so that potential must be available for returning them to the equilibrium position, and the

padding resistors

270, 272 as well as the shrink potentiometers guarantee that there will never be impressed on the various circuits the complete 125 volts available, so that there will always be some potential available for returning the parts to the equilibrium position. I

As may be seen from FIG. 15, when the position of any of the feedback potentiometers matches those of the corresponding signal potentiometers, the position of equilibrium will be achieved and the motors, while still energized, will stop rotating.

The circuit for initiating a cutting cycle, which is to say movement of the ram 38 downwardly along its cutting stroke is indicated in FIG. 16. FIG. 16 shows the

signal potentiometers

62, 80 and 96 for the head, table, and die angle respectively, as well as the

feedback potentiometers

58, 76 and 92 for the head, table, and die angle, as referred to above in connection with FIG. 2. These signallingpotentiometers are provided for each operating position set 200, as described above. The series of potentiometers are electrically connected in the manner illustrated in FIG. 16 to interlocking

relays

274, 276 and 278 for the die angle, table and head, respectively, and when equilibrium is reached, so that the feedback signals exactly oppose those of the signal potentiometers, these relays will cause the

switches

280, 282 and 284 to close, so that the cutting circuit 288 can be closed in order to initiate a cutting circuit. Closing of

switches

280, 282 and 284 will, through

Claims

1. For use in a press, a hollow die adapted to cut through a stack of sheets, and ejector means provided with an ejector plate, said ejector means being situated at least partly within said hollow die for ejecting from the interior thereof sheet portions which remain in the interior of said die after the latter cuts through the stack of sheets said ejector means constituting a cylinder, a double-acting piston adapted to reciprocate in said cylinder and operatively connected to said plate, said piston having a piston rod of a smaller diameter than the diameter of said cylinder thereby forming a first space between said piston rod and said cylinder, a first conduit connected to said cylinder in a second space adjacent to and above said piston, a second conduit connected to the first space in said piston, and both said first and second conduits communicating with a source of pressurized fluid, means rotating said piston, cylinder die and ejector plate as a unit, the latter being capable of a rotational movement of 360* while said conduits maintain communication with said respective spaces.

2. The combination of claim 1 further comprising a stop located in the downward path of movement of said piston to limit the downward movement of the piston in the interior of said die.

3. The combination of claim 1 wherein said ejector means is provided with a yieldable lower plate, and a rigid backing plate to which said lower plate is secured.

4. The combination of claim 1 wherein said first and second conduits are fixed and nonmovable in said cylinder, said first space being formed by said smAller diameter section of said piston rod and a larger diameter section of said piston rod separating said first and second spaces in said cylinder.