US2004566A - Trimming and cutting machine - Google Patents

Description

June 11, 1935. E. M. BRACKETT ET AL. 2,004,566

TRIMMING AND CUTTING MACHINE Filed Jan. 8, 1934 3 Sheets-Sheet l ATTORNEY 3 Sheets-Sheet 2 [dword J1me 1935. E. M. BRACKETT ET AL TRIMMING AND CUTTING MACHINE Filed Jan; 8, 1954 June 11, 1935. E. M. BRACKETT El AL TRIMMING AND CUTTING MACHINE Filed Jan. 8, 1934 3 Sheets-Sheet 3 NTO l NV Edward ATTbRNEY Patented June 11, 1935 UNITED STATES PATENTfoFF 2,004,566 TRNG AND Corr ne MAoniNn Edward M. Brackett, Dietrich'Daneke, and Leo C. Williams, Topeka, Kans, assignora'by'mesne assignments, to Dexter Folder Company, New York, N. Y., a corporation of New York (1934) Application January 8,

21 Claims.

Our invention relates to trimming and cutting machines and more particularly to those of that character for severing stacks of paper, as well as booklets, magazines, catalogs and other classes of sheet material that have been printed or assembled in gangs.

In machines of this character the cut-off knife and its carrier are constructed of relatively thick material in order to withstand the power required to cut relatively heavy stacks of sheet material. Consequently, the cut-off portion of the stack is disrupted due to displacement of the knife as the cut progresses through the depth of the stack. a

It is, therefore; the principal object of the present invention to efiectively apply a hold-down pressure upon the cut-ofi portion of the stack and to progressively shift the holding pressure to allow orderly racking movement of the cut-off portion to accommodate displacement of the knife.

Other objects of the invention are to apply an initial yielding pressure on the portion of the stack to be cut off during positioning thereof, to automatically operate the hold-down mechanism concurrently with the action of the knife,

to r tain a yielding pressure on the cut-off portion of the stack immediately following cutting operation of the knife, and to provide conveyor means to cooperate with the pressure applying means for removing the cut-off portions from the machine in spaced uniform sequence.

In accomplishing these and other objects of the invention we have provided improved details of structure, the preferred form of which is illustrated in the accompanying drawings, wherein:

Fig. 1 is a perspective view of a cutting machine equipped with a hold-down mechanism embodying the features of our invention.

Fig. 2 is an enlarged detail elevational view of a portion of the machine illustrating the mounting of the hold-down mechanism and showing the off-take conveyor in cross section.

Fig. 3 is an enlargedvertical section through the cutting mechanism and associated hold-down mechanism.

Fig. 4 is a similar section from the opposite direction illustrating the hold-down mechanism.

in functional position at the time the knife is descending in making the cut. I

Fig. 5 is a similar section showing the position of the hold-down mechanism after the out has been completed, and at the time the knife is ascending. s r

1934, Serial ire-1705.761 T (C1. 164-51l perspective View of Fig. 8 is a detail perspective view of the holding member.

' Fig. 9 is a cross section through the hold-down mechanism on the line 9 9, Fig. 7. g Fig. 10 is a detail section illustrating th for retaining theholding member in-retracted position onits support. I Referring more in detail to the drawings:

ldesignates a cutting and trimming machine e latch which includes a frame 2 having a vertical knife support 3 comprising verticallyspacedguides 4 and 5 slidably mounting therebetween a knifecarrying member 6'. "The knife-carrying member includes a relatively heavy bar having its ends mounted in the guides 4 and5 and provided with a downwardly inclined lower edge 1 adjacent a.

knife-seating shoulder 8 extending along the forward face thereof. The knife 9 is secured in the shoulder portionl as in conventional practice and has a bevelled edge Ill projecting below the bevelled lower edge of the knife carrier toform a cutting edge ll.

The frame 2 of the machine also includes a horizontal table 12 on which stacks of sheet ma terial to be out are fed under the knife;

Cooperating with the knife ll and movable vertically in the knife support Risa clamping bar memberl3 which descends-into clamping engagement with the stack prior' to'the descent of the knifefor clamping the stack to the table in position so that the cutismade in the proper p1a ce I L The knife carrier 6 and clamp member is are actuated bya suitable mechanism including an eccentric l4 mounted on a driven shaft E6 of a suitable transmission indicated by the housing IT, a connecting rod l8 operably connecting the eccentric with a rocker arm l9, and a connecting link 20 connectingthe rocker arm with the knife carrier, as illustratedin Fig. 1, the 'specificconstruction' of which forms no part of the present invention.

The rocker arm l9, however, is fixed to a rock shaft 2| that is rotatably mounted in a housing 22 .carriedon the side of the frame below the table and which carries a driving clutch for actuating severed portions of the sheet material fromcthe trimming machine, the space between the table 7 In operating the machine thus briefly de-,l

, scribed, stacks of sheet material are moved across. the table 12 so that the portion'tobe' severedlies on the apron 24 and the .pointj'at which'the cut is to be made is in vertical alignmentwiththe cutting edge ll of the knife blade.- The knife mechanism is then actuated-in a suitable manner to effect descent of the knife so that the cutting. edge II thereof cuts across the stack to sever the portion supported on the apron 24 from that retained under the clamping bar 13. As above pointedoutrthetknife as well as its carrier is constructed pf substantiallythick material-to provide rigidity and to assurea straight clean cut through the stack.- Consequently; the inclined bevellecledges l and Ill displace the out- 01f portion of the sheet material astheknife descends so that the-cut ff; sheets arewidely disparsed and disarranged, andit is ourpurpose to retain the cut-off portions' of sheets inorderly stacked condition; for their, successive delivery from the machine by the conveyor22. I V f In carrying out the'present invention werprovidemeansfior, applying initial pressure tothat portion of the stacktha-t is severed byrthe knife while the; stack is being positioned and the knife isdescendingv and a cooperating holding means which is moved into; clamping position with the stack concurrently with .the cutting action of the knife toretain thesheetmaterial in fiat condition during the cut.

As the knife-progressesihto the stack,- we provide for automatically shifting the holdingmeans to incline or rack the cut-off portions of the sheet material to provide space for accommodating the knife displacementbetween the portion of the stack'retained by'the holder I3 and that portion supported on the apron;24, as nowto be described, c ,H 7, V

Slidably mounted in the-supporting frame 2 adjacent the knife-guides .4 and 5 are inwardly extending guide ribsj cooperating with the inner face 26 of .the frame for forming vertical tracks 27 for vertically positioned rackflbars 28 and 29. The rack bars and 2.9,have teeth 30 meshing with pinion gears Blythattare fixed to the ends of a shaft 32 which is rotatably mounted in brackets 33 and 34 carried by the knife-supporting frame, as best illustrated in'Figs. l, 2

The brackets 33 and include flange portions 35 fixed to theinner face 25 of the frame ;by cap screws 36 and have depending ears v3! rotatably mounting the shaft and engaging, the inner face of the gear pinions to retain them in alignment with the rack bars. 7 .p i.

Sleeved on the shaft 32 and having-one end fixed to the bracket 3,3and its opposite end fixed to a, collar 39 isa coil-spring 38 so tensioned as to; counterbalance the weight of thegrackbars and the mechanism supportedthereby,- as later describedyand for retaining the*holdingmeans in selectively adjusted vertical position. The

rack bars are thus mounted for synchronous movement through the'shaft-BZ and the gear pinions meshing with the rack teeth In order to move the rack bars, the rack bar 29 carries a laterally projecting ear on the inner face thereof which is connected by a link 4| with a rocker arm 42 on a rock shaft 43 that is pivotally mounted in the frame 2 at a point above the knife carrier, the link 4| being connected with the ear and'with the free end of the rocker arm by pivotal connections 44 and 45, as illustrated in Fig; 3. The shaft 43 projects from the front face of the knife supporting frame and carriesvan operating lever 46 whereby the shaft 43 may be rotated to rock the arm 42 to cause vertical reciprocation of the rack bar on its support- :ing track; Reciprocation of the rack bar 29 causes similar'movement of the other rack bar *through' the gear pinions and shaft 32, as just described.-

Formed on the lower end of the rack bars are forwardly extending bracket arms 4'! and 48 supporting ends of a tie rod 49 that is secured thereto by cap screws 50. r j z Rotatably mounted in'the rack .bars at a point ,above the tie rod 49 is a rock-shaft 5-! which, with the tie rod and rack bars, constitutes a carriage 52 for supporting the holder mechanism now to be described.

The holder mechanism is best illustrated in Figs. 6.to 9 inclusive, and is shown as including a supporting member havingv ahorizontally positioned body portion 53.provided with an integral i tubular boss 54 on its upper face that is slidably mounted on the guide rod 49 and having upwardly The rock shaft thus cooperates with the guide rod to support the body portion 53 in horizontal po sition relatively to the uppersurface of the apron 24, as clearly shown in Fig. 3.

V The. supporting member thusdescribed, while being retained against pivotal motion, is movable longitudinally of the guide rod so that it may be positioned in 'alignment with the stacks of sheet material that are fed through the-cutter and is adapted tobe retained in selective position thereon by a thumb screw 60 threaded into an 4 opening 6| in a tubular portion 62 and having its end engaging against the guide rod, as shown in'Fig. '7.

In order to provide an initial pressure on the portion of the stack to be severed by the knife, we provide a yielding pressure applying means comprising a flat strip 63 of flexible material having its forward end 64 curved upwardly and rearwardly on substantially. the arc of a" circle and terminating in an attaching flange 65' for attachment to the forward end of the body portion 53 of the supporting member by'screws 66 extending through suitable openings in the endof the strip and into threaded openings in the body portion '53; Therear end of the strip inclines upwardly below thebody portion of the supporting member to a point in substantially vertical alignment with "the'lrock' shaft and is slightly upturned, as'at 51, to permit ready insertion of the stack of sheetsithereunder. V

' Fixed to' the rear end' of the strip is a vertically positioned guide pin 68 that is slidably mounted in the bore 69 which is formed in a boss [0 depending froma web H connecting the arms and 56. The guide pin 68-thus mounts the rearend of the presserstrip to permit yielding movement thereof in an upward direction.

In. order to supplement the tension of the strip member we provide a pair of spring leaves 12 and 13 having their'upper ends 14 fixed to the under face of the body portion 53.:and their lower ends curved downwardly and rearwardly and bearing on the upper face of the rearwardly extending portion of the strip, as shown in Fig. '7. To support and limit downward movement of the end 61 of the strip, against pressure of the-supplee mental spring leaves I2 and I3, the upper end of the guide pin 68 is provided with an opening-15 through which a cotter pin 76 is extended to engage the upper end of the tubular boss 19.

The pressing mechanism just described provides the initial pressure on the stack of sheet material prior to and while the knife is moving into contact with the stack and retains the severed sheet material in stacked condition as the severed portion of the stack is being m ved onto the conveyor belt following the refractive movement of the knife. During the actual cutting operation of the knife, however, it is necessary to" exert a greater pressure upon the stack to prevent upheaval of the end of the stack while the out is being made.

In the present invention this is accomplished by a holding member 11 which is best illustrated in Fig. 8 and includes parallel side bars I8 and 19 spaced apart by cross rods 89 and 8| a sufficient distance to accommodate the body portion 53 of the supporting. member therebetween, as clearly illustrated in Fig. 6. The cross rod 8I connecting the forward ends of the .side bars forms a pivotal sliding support therefor on the forward end of the body portion 53. The cross rod 9| is mounted in downwardly opening notches 82 formed in depending flanges 83 and 84 of the supporting member, the bottom of the notches being closed by spaced bars to form closed slots 86 which retain the cross bar for reciprocatory pivotal movement therein.

The rear end of the side bars I9 and I9 project rearwardly beyond the end 9'! of the presser strip and are cut on rearwardly'inclined planes 8'! and connected by an inclined web 88 as best illustrated in Fig. 8, the ends and web 98 forming a cam surface to be engaged by the beveled portion 1 of the knife carrier when it descends in a cutting operation so that as the knife de scends, the holder member is moved forwardly of the supporting member with the tie rod 8| sliding in the slots 82.

The holder member is normally retained in retractive position, that is, in position for engagement with the knife carrier by a spring 89 having one end fixed to a pin 99 on the end of the tubular boss 59 at a point adjacent the guide rod 99 and its other end to a projecting end 9| of the cross rod 8|. 7

Under certain conditions theholder member may be selectively latched and retained from engagement with the knife bar by a latch 92 pivotally mounted on a pin 93 projecting from the side face of the body portion 53 of the supporting member on the side thereof adjacent the side bar I8 and which has a hook or detent portion 99 adapted to engage over the tie rod 8| when the holder is in retracted position, as illustrated in Fig. 10. By thus latching the tie bar with the detent portion of the latch, the spring 89 is prevented from effecting retraction of the holder and the holder is retained from contact with the knife carrier.

In order to apply pressure on the holding member concurrently with movement of the knife into cutting engagement with the sheet material, the tie rod 89 thereof is operably connected with the rock shaft 2|, as now .to be'de- V The rocker 'arm 99 is fixed to the end ofa rock shaft I99 that is rotatably mounted in a bearing I 9| carried by the frame of'the machine at a point below the table I2, as best illustrated inFigslandZ.

Fixed to the opposite end of the shaft I99 is a crank arm I92 that is connected witha crank arm I93 on the rock shaft 5| mountedon the carriage 52,.the arms I92 and I93 being connected by a link |99. 1

It is thus apparent that when the arm I9 rocks the shaft 2|, the disk 95 will drive the disk 96 to move the arm 91 thereon in an are from the axis of the shaft. Movement of thearm 9-1 operates the rock shaft I99. through the crank arm 99 and operation of the rock shaft rocks the shaft 5| through the arms I92, I93 andtheir connectinglink I94 to move the arm I93 in an anti-clockwise direction, Fig.4. Movement -of thearm I93, however, is limited by a pin1|95 on the rackbar 28 which is engagedby the depend ing lug I 990m the arm. When the lug onthe armengages the pin, it will stop rotation of the shaft but theshaft 2| is free'to continueits movement under influence of the the slip clutch disks 95 and 96.

arm- |9 due to Slidingly mounted on the shaft "5| betweenthe bearings 51 and 58 is an arm I91 projecting fori wardly in the direction of the body portion 53 of the supporting member and which is keyed to the shaft 5| by a spline I98 extending longitudinally of the shaft, as shown in Fig. 7. The forward end of the arm I9! is forked to provide spaced bearing portions I99 and H9. for mounting trunnions III and M2 on a block 3 where by the block is supported between the forks of the arms to adjustably mount a connecting link H4. The block H3 is provided witha vertical bore II5'for passing theupper threaded end N6 of the link H4 that is adjustably positioned therein by lock nuts Ill and H8 threaded on the link and engaging opposite faces of the block;

The lower end of the connecting link I I l'is provided with a head I I9 having a transverse opening I29 therethrough for loosely receivingthe' cross rod 89 on the holder member. When the shaft 5| is being moved in ananti-clockwise direction, Fig. 4, or in a clockwise direction, Fig. '7,

the connectinglinkl I4 moves the rear or cam end of the holder member downwardly in an are from the axis of the cross rod BI and into pressing engagement with that portion of the stack that has been delivered under the path of the knife. Pressure will be retained upon the holder member during the entire movement of the knife due to the frictional contact of the clutch disk'95 with the disk 99, the extent of movement of the'holder member depending-upon the height of the stack, the adjustment of the link I I4, or by the selective position of the carriage.

Should the lugon the arm I93 engage the stop pin I95 before the desired pressure isapplied, it is necessary to lower the carriage. This can be readily accomplished through the lever 49 so that when the holder member is engaged with the stack, there is sufficient movement of the shaft 5| to apply the required pressure in holding the sheet material in position while the cut is being madei A 1 more: limited I adjustmentmightbe made through adjusting the link H4 in the block.ll3.

' 1-Upon return movementof knifethe "shaft 5 I will be rotated in reverse direction to raise the holdermember from contactwith the stack but the pressure strip will remain .in contact therewith to support the. sheets .whilethey are being forwarded onto the conveyor belt 23 upon advancing the stack of sheet material for cutting off another portion.

In using a trimming machine equipped with a holding mechanism constructedand assembled as described, the'stacks of sheet material are moved across the table l2 untiltheplace where the cut is tobe made. aligns with the point of-travel of the knife edge. The. carriage will then be lowered until the presser strip is in desired pressing contact with the top'of the stack by rotating the lever "arm in an anti-clockwise direction to causethe arm 42 .to lowerlthe rackbar through the connecting. link H. 'Movement of the rack bar 29 causes similar movement of the other rack bar due to their geared connection through the pinions 3i and shaft 32 to lower the carriage supporting the holding mechanism. If it is necessary to raise thesholding mechanism, this can be accomplished'by reverse movement of the leveri ifi.

The machine will then be operated to cause the knife to move downwardly toward the stack,.but the initial movement'of the knife first effects movement of-theclamping bar l3 into clamping engagement with the top of the stack before the cutting edge of the knifeengages the uppermost sheet. I J

Concurrently with the movement of the knife and just before thecutting edge thereof engages the stack, the holder member will have been moved into pressing contact with the stack through the driving connection of the clutch disks '95 and 98, arm Bl, connectinglink 98,:arm' 99, rock shaft 100, arm I92, connecting link l04,'arm' I03,

. shaft 5|, arm I01, and the connecting-link H4.

the clamp bar [3 andthesevered sheetsthatare held in pressed condition by the holder; member, which. space accommodates displacement ofthe knife. 4

Upon upward movementof the knife the spring 89.,will return the holdermember as'soon as the pressure is relieved through. reverse' rotationzof the clutch disks..;.. .1.

At the upper limit of'movement'of--the knife,

the holdermember has reached the upward limit of its travel but the presser; strip. 63 retains its pressing contact withthe stack to hold the sheets in-orderly arrangement whilethey are i being moved onto the conveyor b81135 From the foregoing it is apparent that. we have provided a holder mechanism which will effectively holdrthe sheetsjn stack-ed relation while a cut is being made andwhich controls racking or tilting movement of the stack ina forward direction to accommodate displacement of they knife and its carrierso that the stack ofsheetswhen moved onto the delivery belt are in orderly stacked relation. t 'Whatwe claim'and desire to secureby Letters Patentisflv 1 y -1. In combination'with axcutter for severing a portion of..a stack of sheetmaterial, means for applying pressure to said portion, and means for eifecting shifting movement ofthe sheet material cut off progressively with movement of the cutter through the stack; I

2. In combination with a: cutter for severing a portion .of a stack of sheet'm'aterial, a holder applying pressure to said portion of the stack,

' of the cutter to rackthe cut off portion of the stack ,for; accommodating cutter displacement during the cutting operatiom. r

3. In combination with a cutter for severing a portion of a. stack of sheet-material,-a holder for applying pressure-to a portion'of thesta'ck to be out 01f, means for supporting the holder for lateral'shifting movement relative to the cutter, means carried by the-holder forapplying' an initial pressure to said portion of the stack, and means for moving-the holder concurrently with operation of the cutter to rack-the cut off sheets of the stack for accommodating .cutter displacement during the cuttingoperation. 1

4. Ina machine of the character described including a support, a cutter carried by the. support; mechanism for actuating the cutter to sever a portion ofa stack of sheet material, a holder, means supporting'the'holder for movement on the support, and holder operatingzmeans carried by the support and having a slip connection with i said cutter. operating means tomove the holder into pressingcontact with: said portion of the stackxandprovide for continued operation of said mechanism.

i '5. In a machine of the character described including a support, a cutter carried by the support, means for actuating the cutterfor severing a portion of astack of sheet. material, a holder, means supporting .the holder for pivotal and sliding movement on the support, means carried by the support andactuated by said cutter operating means for pivoting the holder into pressing contact with said portion ofthe stack, and means mounted With:the cutter for engaging the holder to efiect sliding movement-thereof for racking the cutoff portion of the stack progressively with the severing operation by the cutter. Y

' 6. In a machine ofv the'character described includinga support, a .cuttercarried by the support, means" on the support. for actuating the cutter for severing a portion of a stack of sheet material, 'a holder for pressing upon a portion of the stack to be cut ofi,' means supporting the holder for movement on the support, means carried by the, holder for applying initial pressure to said portion of the stack, and 'means connected with said cutter operating means for moving the holder into pressing contact with said portion of the stack."

'7. In a machine of the character described including asupport, a cutter carried by the support, means onthe support for actuating the cutter for severing a portion "of a'stack-of-sheet material, a holder for: pressing upon a portion of the stack to be cutoff, means supporting the holder for pivotal and sliding -movement on the, support,

means carried by the holder supporting means for applying initial pressure to said portion" of the stack, means connected with said cutter operating means for pivoting the holder into pressing contact with said portion of the stack, and means movably mounted with the cutter for engaging the holder to eifect sliding movement thereof for racking the cutoff portion'of the stack progressively with the severing operation by thecutter.

8. In combination with a cutter for severing a portion of a stack of sheet material, a holder, means supporting the holder for swingin'gand lateral shifting movement thereof relative to the cutter, and means for. swinging and laterally shifting the holder concurrently with operation of the cutter to press the holder against the cutoff portion of the stack, fan-out or rack the cut off portion of the stack and accommodate cutter displacement in the stack during the cutting operation. i

9. In a machine of the character described in cluding a support, a cutter carried bythe support, means for actuating the cutter for severing a portion of a stack of sheet material, a holde'rfor pressing upon a portion of the stack to be cutoff, means adjustably mountingv the holder on the support for position relatively to the stack of sheet material, and actuating means connecting said cutter actuating means with the holder for moving the holder into pressing engagement with said portion of the stack.

10. In a machine of the character describedincluding a support, a cutter carried by the support, means for actuating the cutter for sever-' ing a portion of a stackof sheet material, a holder for pressing upon a portion of the stack to be cut oif, means slidably mounting the holder on the support for position relatively to the stack of sheet material, actuating-means connecting said cutter actuating -means with the holder for moving the holder into pressing en'' gagement with said portion of the stack, and

yielding means on the holder mounting means for initially pressing the stack prior to engagement of the holder.

11. In a, machine of the character described including a support, a cutter carriedby the support for severing a portion of a stack of sheet material, means on the support for actuating the cutter, a carriage, means mounting the carriage for vertical movement on the support, a holder mounted on the carriage, means for moving the carriage to bring the holder into selective position relatively to the cutter, yielding means on the carriage for initially engaging the stack, and means on the carriage for moving the holder into pressing engagement with the stack during operation of the cutter.

12. In a machine of the character described including a support, a cutter carried by the support for severing a portion of a stack of sheet material, means on the support for actuating the cutter, a carriage movable vertically on the support, a supporting member slidably mounted on the carriage, a holder member pivotally and slidably mounted on the supporting member, means on the carriage for pivoting the holder member into pressing contact with the portion of the stack to be severed, and means carried with the cutter and engaging said holder member for sliding the holder member on the supporting member to effect racking movement of said portion of the stack upon actuation of the cutter.

13. In a machine of the character described including a support, a cutter carried by the support for severing a portion' of 'astack ofsheet' material, means on the support for actuating the cutter, a carriage movable vertically on the support, asup-po-rting member mounted on the carriage, a holder member mounted onthe support ing member,and meanson the carriage for mov-' ing the holder member into pressing contact with the portion of the stack tobesevered.

14. In amachine of the character-described including a support, a knife 'reciprocably mount ed onthe support,;meanson the support for actuating the knife, a pair of rack bars slidably mounted on the support, a shaft carried by the support, gears on'the shaft meshing with the rack bars, means on the support for moving one of the rack bars to eifectmovement of the other, a guide member carriedbythe rack bars and extending longitudlnally'of the knife, a rock shaft rotatably mounted in therack bars,- a holder carrying member slidablymounted on the rock shaft and guide member, a rocker arm onlthe rockshaft, a pressing member supported on the holder' carrying member 1 for applying initial pressuretoa stack of sheet material to be out by the knife, a holding member pivotally and slidably-mounted on the holder carrying member, a

link'conn'ecting the rocker arm withthe'holding member, means connecting the'rock shaft with saidknife actuating mechanism to effect movement of the holding member into engagement withthe stack upon' 'actua'tion of the knife, andmeans carriedby the knife' engaging the hold ing'member -for sliding the holding member for effecting racking movement of the stack during actuation of-the knife. 2

- '15. In a machine of the character described including a support, a knife reciprocably mounted on-the support, means on the support for actuating the knife, a carriage slidably mountedon the support," a 'guidememberon the carriageand extending longitudinally of the knife,

a rock"' shaft rotatably mounted onthe carriage, a holder carrying'm'ernber slidably mounted on the rock shaft and guide member, a rocker arm on the rock shaft, a pressing member yieldingly supported on the holder c'arrying member for applying initial pressure to a stack of sheet material to be cut by the knife, a holding member pivotally and slidably mounted on the holder carrying member, a link connecting the rocker arm with the holder-member, means connecting the rock shaft with said knife actuating mechanism to effect movement of the holding member into engagement with the stack upon actuation of the knife, and means carried by the knife engaging the holding member for sliding the'holding member on the holder supporting member for tuating the knife, a pair of rack bars slidably mounted on the support, a shaft carried by the support, gears on the shaft meshingwith the rack bars, means on the support for moving-one of the rack bars, a guide member carried by the rack bars and extending longitudinally of the knife, a rock shaft rotatably mounted in the rack bars,1a holder carrying member slidably mounted on the rook shaft and guide member, a rocker arm on the rock shaft, a pressing member supported on the arm for applying initial pressure to a stack of sheet material to be severed by the knife, a holding member pivotally and slidably mounted on thewholdercarrying member, a link connecting the rocker arm with the holding mem ber, ,meansconnecting the. rock shaft with said knife actuating mechanism to 1 effectmovement of the holding'member into engagement with the stack upon actuation of the knife, means'carried by the knife engaging theholding member for sliding the holder member-on said carrying member for eifeoting racking movement of the stack during actuation of the knife, and means for re tracting the holding member upon reverse movementof the knife. V I

- 1'7. In a machine of the character described including a support, a knife reciprocably mounted on: the support, means on the support foractuating the knife, apair of rackbars slidablymounted on the support,. a shaft carried by the support, gears on the ,shaftmeshing withth'e rack bars, meanson the support .forrotating the shaft to effect movement ofthe rack;bars,1a guide member carried by the rack bars and extendinglongitudinally, of the knife, a rock shaft rotatably mounted in-the rack bars a holder carrying member slidably, mounted on the rock shaft and guide member, a-rocker arm on the rock shaft, apressing member yieldingly supported on the arm for applying initial pressure on a stack of sheet material to be severed'bytheknife, a holding mem-, ber pivotally and slidably mountedon the holder carrying member, a-link connecting the rocker arm with the holding member, means connectingthe rock "shaftwith said knife actuating mecha-- nismto efiectmovement of the-holding-member into engagement with the stack of sheet material to be severed upon actuation :of theknife, means carried by the knife engaging the holding'member for sliding the holdingrmember on thecarry ing member for effecting. rackingmovement of the stack during actuation of; the knife, -means for retracting the holdingmember upon reverse movement of the knife, and alatch pivoted on;

said carrying member engaging the holding member for retaining theholder member in retractive position.

18. In a machineof the characterdescribed.

including a support, a cutter carriedbythe support for severing a stack ofsheet material, means on-the support for actuating the-cutter, acar-'- riage movable vertically on thesupport, aholdersupport slidably mounted on the carriage; a

holder member pivotally and :slidably mounted on the holder support-means on the carriage for. pivoting the holder member into pressing contact with the-portion of the stack of sheetmaterial tobe severed, means carriedwith the cutter and engaging said holder member for sliding the holder member on the holder support to effect rack: ing movement of said portion of the stack upon actuation of theicu'tter, and means for counterbalancing the carriageton the support to retain ,the carriage in'selective position relative to the stack. 1

19. In-a-machine of the character described including. a support, a cutter carried by the sup-' port for severing a stack of sheet material, means on the support for actuating the cutter, a carriage movable vertically onJthe support, a holder member mounted on the carriage, means for moving the holder member'into pressing'contact with-the portion of the stack to besevered, and means for counterbalancing the carriage on the support to retain the carriage in selective position relative to the stack.--

j I :20. In a machine of the character described including a support, a knife reciprocably mounted on the support for severing, a stack of sheet ma-V teria1-,;mean's on the support for actuating the knife, a carriage including a pair of'rack bars slidably mounted on the support, a shaft carried: by thesupport, gears on the shaftmeshingwith the;rack,. bars, a spring 'coiled on'jthe ,shaft' for balancing the carriage on the support,,a guide;

member carried bylgthe rack bars; and extending longitudinally of the knife, a rock shaft rotatably',

holder with the cutter operating means including 'a-slip clutch for moving and retaining the holder in pressing contact with the stack."

, DIETRICH DANEKE; LEO c. WILLIAMS.

EDWARD M. BRACKETT."

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