US2599776A - Sheet gripper structure and setting means therefor - Google Patents

Description

June 10, 1952 H. E. PEYREBRUNE 2,599,776

SHEET GRIPPER STRUCTURE AND SETTING MEANS THEREFOR 2 SHEETS-SHEET l Filed May 24, 1947 IN V EN TOR. Henri E. Pegrebrune BY mwa/wf@ June 10, 1952 H. E. PEYREBRUNE SHEET GRIPPER STRUCTURE AND SETTING MEANS THEREFOR Filed May 24,.A 1947 2 SHEETS-SHEET 2 l IE -N VEN TOR. Henri E Peyre brune Patented June 10, 1952 SHEET GRIPPER STRUCTURE AND SETTING MEANS THEREFOR Henri E. Peyrebrune, River Forest, Ill., assignor, by mesne assignments, to Miehle Printing Press and Manufacturing Company, Chicago, Ill., a g corporation of Delaware Application May 24, 1947, Serial No. 750,311

Claims. 1

This invention relates to improvements in the structure of sheet gripper assemblies and to a novel method for setting the gripper fingers with respect to their associated supporting pads. The invention more specifically pertains to that general class of grippers and operating mechanism therefor such as are generally used for the handling of sheets in printing presses and similar paper processing machines.

In multi-color printing, the problem of maintaining accurate register of the sheets during their travel through two or more printing units to receive several color impressions in succession, always presented difficulties in the past. 'I'hese difiiculties become more acute as the productive speed of the printing presses is increased.

I have found that in order to assure the maintaining of accurate register of the sheets in multicolor jobs and particularly so when the sheets, during their travel from one printing unit to an adjacent one, are to be transferred several times in succession, the following principal requirements must be fulfilled so far as the sheet gripper structure is concerned.

The grippers whereby the sheets are held to the impression cylinder or to sheet transfer members, must hold the sheets sufficiently firm so as lto avoid any slippage of the sheets even under the most severe pull. 'I'his is particularly apparent in the operation of lithographic offset presses where the ink impression is offset onto the material to be printed by means of a rubber blanket to which the printed sheets cling and therefore must be stripped from it under considerable tension. This is especially true when the printing speed is high.

Furthermore, the gripper units must be adjustable laterally on their support, such as for instance on a shaft mounted within the gap of an impression cylinder, so that they can be most advantageously distributed longitudinally of the support.

All of the grippers of the same series must hold the sheet With the same pressure and be capable of retaining their original holding power underl varying conditions for long periods.

The grippers must also open and close accurately and in synchronism in order to maintain the register of the sheet during their transfer from one sheet carrying member to another.

The means for closing the grippers must be such that the fingers close onto their supporting pads with minimum shock and vibration in order to avoid slippage of a sheet between the grippers and their pads. The grippers must also be easy to reset when required and easy to replace.

With a View to accomplishing the above reprovide means whereby, in aspringurged gripper; finger, the spring tension of the 'finger Withre-f.

spect to its associated support or pad, can be preloaded and the preloading varied at will by means of an adjustable element, andwhereby positive opening and closing relation of` thegripper finger with respect toy the pad can be established.

Another object of the invention Vconsists inthe provision of a novel combination of elements iny cluding a spring actuated gripper finger sup'- ported on a movable bracket and coactingfwith `a support whereby the gripper unit is securely at-` tached to a mounting such as a gripper shaft'.

The improvement also includes means fori pre-V loading the spring whereby the gripper'finger isi held to its supporting pad, and adjustable means whereby each gripper can be set in a manner that all of the grippers of a series mounted on asha'ft or the like, will open in synchronism at a prede-r termined point. ,Y Y

A more specific object of the invention resides in a novel gripper assembly and mounting therefor in which each gripper unit includes a gripper finger support arranged for free movement. on the mounting and a bracket rigidly secured to the latter. For the purpose of preloading the bite'of the gripper finger, and for varying such bite, a spring is interposed between the gripper support and the bracket, the tension of which can be varied by adjustable means which latter also serve to provide a predetermined relative movement between the gripper support and the bracket to thereby establish positive opening relation between the gripper finger and its pad. y A further object of the invention and characteristic departure from known operating mechanism for the grippers is the provision of cam means whereby they are positively closed, and of spring means for opening them. Heretofore, thev closing of the grippers was effected by springs bility of sheets slipping between the fingers andy their supporting pads is minimized.

A still furtherV object of my invention resides in the provision of a novel method of applying cooperating pads for holding a sheet tight.y Thereupon, the means whereby the preloading is eiected is released and a certain predetermined? clearance is established, preferably between said latter means and the bracketswhichzform.part? of the gripper and which arerigidly secured-'to`r the gripper supporting means.4

This clearance is to be exactly the same for all the grippers ofone series andfhastothe-efect' that the grippers are opened in synchronism, thereby assuring that allthe grippers ofia series will release the sheet simultaneously to avoid any disturbanceyin theregisterof thesheet Thef importancerr oft. opening?Y the? `gripper's ini-4 synchronism maywell beflikenedtoithat"ofataw petr-adustmentof Valvesgir'r automobileng-ines which" also demands a` most accurate-.setting-1to1 function satisfactorily, namely to openrfandiclcse:

atV certain' predeterminedrpointsfin' the cycle: of

pen structure is the'rst one wherebyfI have beenM ablerto '.denitely accomplishrrthef-above; require;

ment;` is'- proof that itfhas idistin'ctnovel manmade-- vantageous features overrand'above='gripper'struc turesiusedfheretofore.,

Still another; object vof tthe inventionresidesl in'.

theffprovisionrof means whereby the'ten'si'onlwith which? ithefgripper: fingers-tare. to engage?L sheets canebezreadily `preloadedandfzin a;mannerf that 1 all :oi' the l,gripper fingers of :one yseries'.='atta'ch'ed "tov 1 afcommonk supporting member 'shalls apply zoutwarsheeiwitlrrthe .same pressure: Furthermore; that@v thefextent4 offzpreloading can'` be 2 readily varied'i at wilhsofgthat the-'biteor lgripper rtension'u may be* more,-onless,t in zone seriesithaninanother;

' Anotherrainrloffmy inventiorr'reside'sin a novel* grippersettingf procedure; ,whereby asynchronous 4 sheet carrying cylinder and including actuating means therefor, and

Figure 6 is a sectional View, similar to Figures 3 and 4, but depicting the relative positions of the parts when the bite of the gripper finger has been preloaded .to amaximum;

Referring lnow to Figuresel 'and 2 of these drawings, one of the improved gripper unit-s which embodies the principle of my invention, is shown bywayA ofexample as applied to a gripper shaft Iimounted'within the gap I i of a sheet carrying Vcylinder i2 portion of which is shown in section.

Thel'fpreferred structure or the unit includes a brackets! whichf'is securely clamped to the shaft lineits*operative-position, by any conventional means;sucha's bolts l 5.

The 'gripper finger l is carried by a supporting member l1 which is arranged on the shaft I0 to freely-rotate with relation thereto. One end of this shaft extends, through the cylinder wallV I8 and has secured'th'eretotalbellcranki1 lever-- i9 which `1transrriits.1rocking.motionto the shaft@ l 9"? and whichfais; formedh with;l the arms Z'fand` 'It' The; lever? l S tis; vclamped'tolth'e'freeI end of if th -f shaft I Il by fme'ans :of -boltslZLandis secured t"s-`- operatiiei positio'nkbyra iWoodrui-'l key 2321012 the-flike'. To thefreeiend'ofl"arm.' Eil'fispiv'otall'f-fA mounted ra springicontrclled rod .2 5v which -is urged? upwardly by means ofla. coil spring: 25 mounted' orrit."l Ihefouteriend of the arm 2 i carriesfazcam roller. or f'follower 27 'whichl rides fonatstationaryandtcontinuouscam; disc 23.; The lower end-lfofif thisfconnectingrod isguided-y-andith'e springsup ported .in any conventional--m'annerv such? as byait bearing yblock, not shown; soli that-it willifdllo'w the 'movement' impartedzto theA arms-'Zilli byE the;l

drawings, the follower roller 2' rides-*overfthef' highportion'toi thecamiiwhich is ooncen'e'- tric with cylinder l2, consequently the gripper"v finger' fis -closed on its associatedV4 supporting.

then compressed; v

The stationary; continuous cam dis'cv 28"is' shaped so as toprovidethe followingactions':

vention willi' be 'apparentfrom". the appended claims when-'read irry conjunction .withT thefollow# ingrr descriptionprandA accompanying: drawings whichillustrate" merelyby way"'off example. one preferredrform wherebyzthe@principlesof `'my inventionsinay be accomplished;

Inzthedrawings; which .illustrate lfone p'referred 'l embodiment vof :my invention; and; wherein ,likeY reference',V characters: are.: .usedj to designate -V like parts.

Figure 1 represents alf-side' elevationalviewof Vmyimproved sheetfgripper Y unit; showrras 'l ap plied to af sheet :carrying cylinder,r andincluding largedscale,v of the agripper;unit and showing-1the gripper nger closed-omits@ associatedipad';

Figure :4'is 'a1 similar ,viewbut Vshowingthe grip: y

Figure 5 illustrates the farrangement of taseries 1' of igripperaunitssapplied; to: a gripperrshaftrof -a Itl will' holdthe grippers closed positivelywhile-`r holding 'a' sheet.' This is accomplished ,by D10vid. ing `a high'cam` surface whichvis concentricV with; in very close limits to the axis .of the sheet car. rying cylinder l2; Y

This concentric surface .occupies arranglesubl-I stantially equal to the included angley between the points of transfer 4from onefsheet.. carrying' member to another. Y

The grippersiofv a series will-vallo-pen .atrafpre-V determinedpointfto release a sheet andwillpro vide the required clearance with the leadingedge' of the sheet being released.

Itfwill keep theA grippers -open'untilthenext' point ofwclosing isreached; This is'done byfproev viding a low surface'or its equivalent, on the 4cam;

disc, which surface is substantially Aconcentric to the axis of thesheet carrying member:

Thefgrippers'will close att-he desiredt ratefoff motion.A in order to first clearthe edgeoffasubA sequent sheet andthen apply theigripperLI-ingers smoothly'onto its asscciated'pad; toihold the' sheet;T

The :openingand closing z motions of the i grip# pers are' controlled by suitably shaping thosev cam-'fportions which connect the high and low points of the disc.

This novel manner of bringing the gripper finger and associated pad into cooperative or sheet gripping relation with each other, is an important; function of my invention. It eliminates any vibration of the gripper finger usually present when grippers are closed onto their associated pads by means of springs as heretofore. Therefore, the possibility of disturbing the register of a sheet while in the bite of the grippers is minimized.

Upon continued rotation of the cylinder I2 in the direction indicated by the arrow in Figure 1, the follower 21 will eventually reach the low portion 32 of the cam 28. Consequently the shaft I0 will .be rocked in the anti-clockwise direction by the pressure of spring 26 exerted on the arm 20 of the lever I9, and the gripper will open, a position indicated in Figure 4. v

For a more detailed description of the gripper unit, I will now refer to Figures 3, 4 and 6 of the drawings and which are cross sections taken along a vertical plane extending through the center of a gripper unit such as is illustrated in Figures 1 and 2.

The gripper finger I6 is preferably secured to its supporting member I'I by means of a bolt 35 which is threaded into a tapped bore provided in the cross piece or brace 36 which connects the side walls of the gripper finger supporting member I1. The bolt 35 is locked against accidental loosening by means of a locking washer 31. At its inner end the bolt 35 is formed with a reduced extension 38 which extends into a compression spring 39 and serves to support the latter in its operative position.

The bracket I4 is formed with an upwardly extending arm 40 provided with a recess 4I for accommodating one end of the spring 39.

Opposite to the cross piece 36 of the supporting member I 'I is provided another cross piece or brace 42 formed with a tapped bore, into which is threaded an adjusting screw 43 which latter is also secured against accidental loosening by means of a locking washer 44 applied within a slot formed in the brace 42, as is clearly shown in the drawings.

'I'he effect of the lock washer 44, which is of the split type, and which is placed into said slot with the expanding ends at the top, tends to force the outer section of the .brace 42 away from its body section in a manner that friction will be applied between the thread of the adjusting screw 43 and that in the brace.

Preferably a cover plate 45 is `arranged to extend over the upper open portion of the gripper supporting member I1 and between the side walls of the latter. This cover plate is clamped between the gripper finger I6 and the cross piece 36 by means of the bolt 35 which secures the finger to its support II.

In Figure 3, the relative parts which constitute the gripper unit just described are shown when the gripper I6 is closed on its associated pad 30, Whereas in Figure 4 the gripper I6 is shown in its open position.

The adjusting screw 43 has two functions, first, to prelo'ad the spring 39 through which contact pressure between the gripper finger I6 and its pad 30 is accomplished. This is illustrated in Figure 6, showing 'the screw 43 in its practically innermost or maximum preloading position, contacting the arm 40 thereby compressing the spring 39.

The second function of the adjusting screw 43 -I is that of providing a predetermined gap or clearance 46 between the outer face of arm 40 of the bracket I4 so that there will be a predetermined movement permitted -between the bracket I4 and the gripper finger supporting member' I1, see Figure 3. Preferably this gap should not exceed .003 to .004, however, for reasons of clearer illustration this gap is shown in this and other figures as greatly exaggerated, as will be readily apparent from `the description of the method of setting the grippers to be given hereafter and in which the purpose of this clearance will be explained.

Upon opening of the gripper nger I6 bythe mechanism herein described with reference to Figures 1 and 2, the outer or operating face of thearrn 40 will be forced into contact with the adjusting screw 43 by the expansion of the preloaded spring 39, a position shown in Figure- 4.

I will now proceed to describe the manner by which an individual gripper unit is applied to the rock shaft I0 and set for operation.

Upon placing the bracket I4 and supporting member I 'I onto the rock shaft I0, and setting the cam follower 27 onto the high portion 3I of the cam 28, the spring 39v is prel-oaded as shown in Figure 6 by turning the adjusting screw 43 inwardly against the arm 40 of the bracket I4 to establish the desired gripper bite between the gripper finger I6 and its pad 30. Thereupon, the finger I6 is brought manually into contact with the pad 30 and the bracket I 4 is securely locked to the shaft I0 byv means of the bolt I5. It will be understood therefore, that upon locking the bracket I4 onto the shaft I 0, there can be no relative movement between said lbracket and the gripper supporting member I'I until the shaft I0 is rocked to open the gripper finger I6. Therefore, by loosening the adjusting screw 43 until contact with the arm 40 is broken, a predetermined gap or clearance between it and the operating face of said arm can be established, and as a consequence the spring pressure previously applied to the screw 43 will be transferred to the gripper finger I6 in contact with the ypad 30. The purpose of this gap 46 is to provide a predetermined point at which the gripper finger I6 will positively be moved out of contact withthe pad 30. It will also be understood that the gripper finger will not o-pen until the arm 40 has contacted the adjusting screw 43 during the rocking motion of the shaft I 0 in the anti-clockwise direction as sho-wn in Figures 3 and 4, the latter figure depicting the arm 40 in such contact relation with the adjusting screw 43, and showing the gripper finger open. Furthermore, the ,provision of said slight clearance limits positively thefextent of movement of the finger I6 away from its pad 30. 1 In`Figure 5, I have illustrated a series -of gripper units applied to the gripper shaft I0 of a sheet carrying member such as the cylinder I2 and I have also indicated the operating means for that shaft lsuch as is illustrated in Figures 1 and 2 hereinbefore described.

The method of setting a series o-f grippers on a common supporting member such as shaft I6, includes the same steps as just described in connection with the setting of an individual gripper unit, but it adds the step of preloading each individual unit exactly alike by applying the same amount of preloaded pressure to the arms 40 of each unit by the adjusting screws 43. It also necessitates the step of providing exactly the same clearance or gap between the arm 40 and the adjusting screw 43 in each unit. In this manner all of the units of a seri-es of grippers will be preloadedexactly alikeand by'providing a micrometrically measured gap 46 for all units, the point of opening the gripp'errngers I6 with relation to theirpads 30 will be accomplished definitely by the arm 40 moving into contact with the adjusting screw 43 and consequently, all of the gripper flngersin a series of units will open in synchronisrn., The closing point of the gripper fingers onto their pads is likewise controlled by the clearances or gaps provided be-tween the arm 40 and the adjusting member 43.

For the purpose of applying a feeler gauge in order to establish a predetermined-and accurately measured gap in each unit ofva series, a clearance 4-8 is provided in the supporting member I1.

While I'V have chosen to illustrate and describe herein oneV preferred embodiment of myV invention, I .wish it to be understood ,that I desire to cover any such modifications in the design, arrangement of parts, and in the method of settingv the improved ,grippers units, thatV will come within the scope and meaning of the appended l claims.

preload the bite of the linger, said means also serving to provide for a predetermined relative movement between said :support and said bracket, cam means associated with said operating shaft for closing the gripper finger onto its -coacting pad, and spring means acting on said shaft for opening :the finger.

2f. A spring gripper assembly, comprising Vin combination, an ,operating 'shaft for supporting a series of g-ripper units, each unit including a gripper finger support mounted for free movement xabout the axis of said shaft and a bracket rigidly secured on the latter,- a pad coacting with the gripper nger, springl means interposed between said :support and said bracket, an adjusting screw carried by said spring gripper support for adjusting the tension of said spring means to thereby vary the pressure exerted by the gripper finger onto its associated pad and to therebyY preload the bite of the nger, Ysaid means also .ser-ving to provide for a predetermined yrelative movement :between 4said support and said bracket, restrain-ing means for maintaining -said screw in its adjusted position, cam means associated with said operating shaft for closing the gripper finger onto itsv coacting pad; and spring means acting on said shaft for opening the finger.

3. A sheet gripper unit having in combination, a gripper shaft, a spring urged support concentrically mounted on said shaft for free movement about the axis thereof, a gripper finger fixed to said support, a member lfixedly mounted on said shaft for movement therewith to open and close said gripper finger, and means associated with said support and adjustable whereby to preload the bite of said finger with respect to said member, said means also being movable when said finger is inclosed position to vary the opening and closing relation between said support and said member.

4. A sheet gripper unit comprising in combination, an oscillatable supporting shaft, a gripper finger having avrear wall in spaced relation therewith, said gripper finger being mounted on the shaft for free movement about the axis of the shaft, stop means fixed to the shaft and having location between the gripper finger and said rear wall, resilient means interposedbetween the stop means and the lgripper nger and resiliently connecting said stop means and gripper finger so that oscillating movement of the shaft is imparted to the gripper finger, cam actuated. mechanism having operation to oscillate the shaft to effect opening and closing of the gripper finger, and adjustable means coacting with the stop means and the rear wall to selectively vary the tension of Said resilient means on the gripper finger to predetermine the tension of said gripper finger when in closed position, said adjustable means being movable when said finger is in closed position to vary the relative spacing between said adjustable means and said stop means to selectively control the opening and closing of said gripper finger with respect to said cam actuated mechanism. v

5. A sheet gripper unit as dened by clair-n 4, wherein the adjustable means comprisesY va screw threaded in the rear wall for adjustment toward and from said stop means.

HENRI E. PEYREBRUN-E,

REFERENCES CITED The following references are of record i-n the le of this patent:

UNITED STATES PATENTS Number Name Date 1,296,008 Rich` Mar. 4, 1919 1,535,224 Harrold Apr. 28, 1925 2,088,862 Lang Aug. 3, 1937 FOREIGN PATENTS Number g Country Date 507,522 Great Britain June 16, 1939 310,177 Great Britain Apr. 25,V 1925 556,710 vGermany s- Aug. 13, 1932

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