US1050191A

US1050191A - Sheet-gripper mechanism.

Info

Publication number: US1050191A
Application number: US66562411A
Authority: US
Inventors: Joseph White
Original assignee: Individual
Current assignee: Individual
Priority date: 1911-12-14
Filing date: 1911-12-14
Publication date: 1913-01-14
Anticipated expiration: 1930-01-14

Description

N J. WHITE. SHEET GRIPB, MECHANIASM.

' Patented Jan.14,19h13.

APPLIUATION FILED B30121911.

pGyQl '2 SHEETS-Smm 1.

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SHEET GRIPPER MBGHANISM. APPLICATION FILED DEG 14, 19112 1,05.0,191 Patented'an. 14, 1913.

2 SHEETS-SHEET Z.'

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ATo au whom, it may concern.'

sheet gripping mechanism 0n the impression the sheet is to beattached, and to place on hold the front edge'of the sheet fed to the i by being forced into these depressions by the JosErn wHrrE,` or PIscATaWAY TOWNSHIP, m'DDLEsEx country, NEW yJERSEY'.

1 ,O5(I),191 Specificationof SHEET-GRIPPER MECHANISM.

Leners intent. Patented J 1913.

Application led December 14., 1911. Serial No. 665,624.

A Be it known that I, JOSEPH WHITE, a citizen ofthe United States, residing at Eiscataway township, county of Middlesex, State of r New Jersey, ostoice address Boundbrool, New Jersey, Ihave invented ce ain new and useful Improvements in -Si eet -Grpper Mechanism; and I do declare the following. to be a full, true, and exact descri tion'of the said invention, such 'as will ena-b e others skilled in the art to which' it appertains to 'make use of the same.

This invention relates particularly to cylinders of'printing machines, particularly planographic presses, which luse a. blanket of yielding material, usually of rubber, on.

necessitating the passing of the same sheetthrough the press a number-of times today on the diii'erent colors, which must be in register. In such impression cylinders, to which a sheet is attached temporarily during the printing-operation,it is customary to provide an oscillatory shaft mounted on earings in the ends of the cylinder, and just in front of the impression surface to'which vthis shaft a series of lingers so that'when the shaft is oscillated, these' fin ers will be brought inA contact with an a utment and cylinder. It has heretofore been usual'to use the front portion of the blanket covering the impression surface of the cylinder as this abutment and in manyl cases, this is fairly satisfactory. However, the succession of blows struck b each linger against this yielding blanket Awhen taking the sheets serves eventually to make depressions therein, and I have found this to be a source of loss of register,'unless great care is taken to avoid it-and that'in some cases, it is `racti. cally impossible to avoid it, even with thegreate'st care. This loss of register arises because sheets fed to such a surface are indented or corrugated along their front edge -grippers When such a sheet is again fed. to a set of'grippers having different relative positions along the front of the impression surfaces, these indentations or corrugations have a tendency to make the 'gripping pointuncertain and s o destroy theregister'of the If the grippers at the second printing are set to fall exactly in the same plafces'as did the grippers in the first printin'g,`fth`is diiii- 'cultyL is minimized, but this involves considerab'le time and nicety' in thesetting of the second set of grippers. Moreover, when the press-has an' impression -cylin'd' `1"""pro'vided` with two or more sets 'ofi-impression" sur- `faces, each with its own set of `'ippers, which take successive sheets fromt esame pile and deliver them to -'thesanm'a pile, the .diiculty is greatly"increased.'l In' thevcase of. zin-impression cylinder -having two' impression surfaces, for-instance, `the vdelivery pile, theoreticall should `be composed of alternate'sheets printed on the alternate surfaces of the impression cylinder. But practically, since sheets'are destroyed'from time to time and withdrawn from' the delivery pile, and since the'pressit'self makes partially idlerevolutio'ns at times, this theoretical alternation is not' attained. -l'Hence, when the pile is 'passed through the'- press a -second time, as in multicolor printing, a sheet which was first presented' to the grippers of one impression surface may be presented to the same set of grippers orto the other set, as chance determines'. lI [f the gri pers' ofthe second set are not identical wit the first set in arrangement,'this results in loss of re' 'ster for such of the sheetsas are presente to a set of grippers otherthan theone to which they were first presented.A

I have provided a mechanism which overcolnes all of these objections and enables the production of sheets in register ,no matter ow many times or to how many different sets of grippers the sheets' are presented, and which, whenv used in a cylinder -hav-ing a plurality of impression surfaces,"enables the production of a pile 'of'.printed sheets having .the edges flat andi-smooth, so that .the sheets may -be fed tothe -same or' other cylinder without loss of register.'

As a first step in accomplishing this result, I make the abutments for the. movable grippers independent of the'impression sui'- ace of the cylinder. As one'way toaecoim plish this, I provide a flat bar which may be pressed against`the front edge of the impression surface and locked in place. vIf this bar were composed entirely of metal.

of the sheet in its relation to the cylinder there would be a hard and unyielding hold:`

impres on produced by the second print-ing.

grippers. Thesheet is liable to be torn i'n- This bar is held in place by screwsQLt. such a ease by reason of the pull Aexerted on l threaded in brackets attaehedto the imthe front edge ofthe sheet from the stretchpression cylinder, such screws acting against ing and giving of the rubber blanket of the the bar between the projection -Qi :uid a impression surface when it contacts-with the i front edge of the impression surface to printing surface.' This difficulty I o\'e.- t clamp the bar against this impression sureoine by making the grip between the abutface and so clamp the rubber blanket thereto. m'ent and the gripper a yieldin'g'one of sub- Y stantially the same kind as would be ob---i ha`rieed material 26 against which the tained if the gripper impinged directly i screws 24 bear, each of these plugs having upon the rubber blanket. By constructing a sloping face, as shown in the lrawings. to

4vent; the indentation of the front edge o'titliistruction, I am also enabled to obtain a printing surface.

the gripper bar as will be more fully heref prevent the bar from being withdrawn after inafter described, I am also enabled to prv-fvv the screws 2l are tightened up. The bar lio\\'e\'er,'is not attached"permanently to the iinpressioi'i cylinder, so that, on loosening By such conl up screws 24, the bar is free to be withdrawn from the cylinder to give ready access to the more definite grip on the sheet than obimpression surfaces, and thus make the retained between the rubber blanket and the placement of thenbberblankets easy. Obingers, and at the same time'to make this viously, this sloping face might. be made digrip :sutiiciently yielding to prevent the tearreetly on the surface of thebar itself. ing f the sheet. by'reason of the stretching '.Portions of the upper edge of the bar 22 ofthe rubber blanket when running over the are used as the active area onwhich the grippers 19 rest to grip the sheet. The bar `lVith these and other objects in viewfthe itself is cut away at the proper place, invention consists of certain novel features' shpwri at 27 27, Vto admit. the passage of sheets, as is done when the gripper iinpinges directly upon the blanket.

of construction and arrangement vof parts' grippersbn' mechanism, .such as feed or deas will be morefully described and pointed vlivery cylinders, leoperating with the imout inthe appended claims. pression cylinder. 'l`lie remaining portion In the drawings, Figure. 1 represents a ofthe .upperedge of the bar, therefore, be-

' section of an impression` cylinder having l comes substantially individual blocks, with two impression surfaces of the particularl ing-reeled up on the rods 15 and 16 and .-A of aportion of the cylinder shown in Fig. 1.

two sets of gripper mechanism and. two imany one of which ag 4pper'on the shaft 1T pression surfaces. Fig.` 2 is a side elevation may be made to cooperate. In' my preferred l form, .I for'in pockets .in the upner edge ot' Fig. 3nisun cnlargedfpcrspective,view ofa f each oneof these blocks and ace therein port-ion of the impression cylinder shojving rubber plugs which extend .preferably well particularly my novel gripper mechanism. below the, surface of the block and which The bar 22 is provided with plugs ofingof the sheet between it. and the metallic 'bn thei'front edge 'of the impression surface.

he corresponding parts 'are referred to may and preferal'ily do extend slightly above both 1n the drawings and the following dethe surface of the block. This is shown seription-iby. similar reference characters,A most clearly by reference to' the block 28 in In the drawings, 1Q represents the shaft Fig. 3, in which are shown two round plugs of the impression cylinder and 11 and 12', Qi) inserted in block 28 and extending slightly above its upper surface. It is obcylinder which I lhave shown lfor purposesvious that these rubber plugs alone will give of illustration. the saine kind of a yielding grip to the sheet 13 and 14 are rubber blankets stretched as would behad if the gripper contacted diover the impression surfaces 11 and 12, be- 'reetlv with thil rubber blanket. 'Since the SllOGlS liever tear when they are held directly on in@ rubber blanket'. by the grippers, due to the fact that the grip so obtained is e sufficient-ly yielding toperini'tthe paper to 17,'and 18are gripper shafts of the ordimove slightly therein in response to the pull nary type, having grippers`19 thereon, also of the rubber blanket in stretching duringr of the ordinary type. The shaftsl? and 18 th'e.printing. it is obvious that the sheets are oscillated in the usual manner in the will not., and as I have found by experience. rotation ofthe cylinder by the usual tum- .they do not tear when held between the rubbler heads 20. ber plugs 29 and the gripper 19. It will 2l--2Larebearings to support the grip- .also be seen that while the constant poundpei` shaft and it' will be understood that the ing of the gripper 19 on the plugs 2t) might grippers, when 1n the closed position shown eventually compress them in the same way m FigsLl and 2, are held in such position y a spring in-theusual manner. rubber blanket, this may be compensated for 2 is an abutment bar, vresting on projecfrom time to time by removing the. rubber tion 23 on the impression cylinder and also 1 plugs and inserting others, or by removing clamped at the front edge of the respective impression surfaces, as will be more fully described. hereaftcr.-

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as the' grippers compress and indent the i the plugs and4 raising them slightly, as by inserting pieces of paper under them, so asto bring the'top surfaces vof theplugs back to their original. positions. This is clearly a much simpler, cheaper and easier 'operation' l'than the replacing of the expensive rubber w blanket. It will also be seen that', by making' the area of the rubber-:fall Ainside the contact area .of the nimmhle gripper, as I preferably do, the .rubber is depressed .over

' its entire surface and -cannotform-grooves into which the edges of the paper are indented, as 1s the case when the grippers act -..direct-lyon the impression blanlet. .I have found that the bestresults are obl' tained whenlttie plugs of rubber `29 are proportioned so that,-when struck by the active gripping surface of' the gripper 19, Vimpelled by theusual' spring for closing such grippers, the plugs will be compressed, sutliciently to permit the to Asurface thereof to come flush with the sur ace of the block 28, and by proportioning the area of the plugs 29 to the active area of the gripper 19 so that,^when this compression takes place, the

gripper 19 grips -the sheet not only between itself and the plugs 29, but also between itself and a portion of the surface of the block 28. In other words, to produce the 3o best results, 'I provide a gripping contact between .the gripper and the abutmentwhich is partially yielding and partially unylelding. By this combination I obtain the certainty of registrationdlad between two unyielding surfaces, and at the same time the rubber plugs furnish a relief device to prevent the tearing of the sheet due to' the stretching of the rubber blanket when under'compression. This same result may 40 lbe obtained, though not perfectly, by having the surface of the rubber plugs normally just'iush with the surface of the block 28. A

`While Ihave shown the plugs 29 as round,

it is obvious that they may be of any desired shape and in any number to produce the results required. It is desirable, however, that they extend a considerable distance below the surface ot' the block 28 whiclithcn forms a support for the plugs and prevents any excessive sidewlse distortion when'the pressure of the sheet produced by the printing impression tends to pull'he sheet out of the grippers. It is obvious,

- hmvever, that many of the results may be 'which I have shown and described, and it is also obvious that many of the important results of my mvcntion may be had by using la metallic spring or spruighcld surface mslcad of the rubber plugs. since a yielding surface may thereby be obtained. rl he elaslLelio-,191 i;

1"' -ltic `or yieldlng surface. may also be made a part 'of the inoyable, instead of the stationary, grippers. i Having now described my invention, what I claim as new and desire to secure by 'Letl -ters Patent is as' follows:

1. In a printingm'achine, an impression cylinder, a rubber blanket on the impression surface thereof, grippers mounted in said cylinder. and abutments for said grippers Said cylinder, the active surface of said abut- Ilnents being'partiall'y hard and unyielding and partially soft and yielding.

l 2. Ina printing machine, an impression cylinder, a rubber blanket on the impression surface thereof, a gripper shaftl in said cylinder, grippers on said shaft, a gripper abutment bar-in said cylinder, independent of Said impression surface, and having elevated blocks on its edge arranged to form abutments for said grippers, the surface of each of'said abutments having a portion thereof hard and unyielding and -the remainder soft and yielding.

3. In a printing machine, an impression cylinder, a rubber blanket on the impression surface-thereof, a gripper mechanism in said cylinder, abutments for the grippers thereof independent of said 'rubber blanket, the active surface of eachv of said abutments being partly of metal and part-1y of rubber.

4. In a printing machine, a cylinder having a sheet carrying surface, a clamp bar arranged to be heldremovably against the front'edge of said sheet carrying surface and clamping means attached to said cylinf' der and adapted to contact with said bar carrying surface, said bar being provided Awith inclined surfaces arranged to' co-act with said clamping means to prevent the removal of Vsaid bar from said cylinder.

5. In a printing machine, an impression cylinder having a. projection adjacent the 'front edge of the impression surface thereof, asheet gripper abutment bar extending alongnsaid front edge and resting on.said projection, and clamping means attached to. the cylinder and adapted to engage said bar between said front edge and said projection, 'to hold it against said front edge.

cylinder having a projection adjacent the front edge of the impression surface thereof, a sheet gripper abutment bar extending along said front edge and rest-ing on said projection, and clamping means attached to the cylinder and adapted to engage said bai between said front edge and said projection, to hold it against' said frontl edge, said clamping means and., said'bar being constructed and arranged to permit the removal of the said bar from the cylinder when the i clamping means are released.

and press it against the edge of said sheet' independent' of the impression surface of (3. In a printing machine, an impression l 7. I naplanog'graphie printing machine, an i impression cylinder hai.'ingr a plurality of impreesion surfaces, each of said surfaces having an elarftie blanket thereon, a set of sheet taking grippers for each of said surfacearranged to operate at substantially 'the same point in the rotation of the cylinder, and abutments. for Said grippers, independent of said impression surfaces and blankets, .said grippers and butments being constructed and arranged to have a yielding grip onthe sheet -held therebetween.

the same point in the rotation of the cylinder, and abutments for said grippelfs, independent of said impression surfaces and,

blankets, 'each of said abutments bein pro' ided with an elastic gripper conta surace. y

9. In a plano raphic printing machine an impression cy index' having u plurality 0% impresion surfaces, each of, said surfaces having an elastic blanket'I thereon, a set of sheet taking grippers for each of said surfaces, arranged to operate atsubstantielly 43i= the same point in the. rotation of the cylinden' and abutments for saidv grippers, lndependent of said impression surfaces and l blankets, each of `aid abutmente being;r rovided with a partially'hard and unyiel ing and a partially soft and yielding gripper Contact surface.

" Y JOSEPH WHiTE.

Witnegses:

Gannon F. SCULL, Amnn'r C. WmCHExs.