US2144752A - Rotary sheet transfer mechanism - Google Patents

Description

a E. F. DUDLEY I ROTARY SHEET TRANSFER MECHANISM 4 Sheets-Sheet l uaigg,

Filed Dec, 25, 1936 Edward FD Jan. 24, 1939. E. F. DUDLEY 2,144,752

' ROTARY SHEET TRANSFER MECHANISM Filed Dec. 25, 1956 4 Sheets-Sheet 2 czr .Dzz c g 46 4 v I f Jan. 24, 1939. E. F. DUDLEY R OTARY SHEET TRANSFER MECHANISM Filed Dec. 23, 1936 4 Sheets-Sheet 3 Jan. 24, 1939. DUDLEY 2,144,75 2

ROTARY SHEET TRANSFER MECHANISM Filed Des 25, 1956' 4' Sheets-Sheet 4 EJIIIIQQ'QQQQQQEFDDDEl Patented Jan. 24, 1939 ROTARY SHEET TRANSFER MECHANISM Edward F. Dudley, Oak Park, Ill., assignor to Michle Printing Press & Manufacturing Company, Chicago, 111., a. corporation of Illinois Application December 23, 1936, Serial No. 117,391

15 @laims.

The invention relates to the art of printing and has particular reference to improvements in rotary sheet transfer means to assure perfect register of successive impressions in a multi-unit press such as a multi-color press. v

The improvements of the present invention have been especially designed for sheet fed multicolor machines having a plurality of printing couples arranged in tandem for unit operation it) and wherein the sheets are transferred by one or a plurality of transfer cylinders from one printing couple to the next adjacent printing couple.

In multi-color presses of the above type accurate registry is absolutely indispensable if performance of the highest grade is to be secured. Machines as heretoforeconstructed have only approximated such performance, notwithstanding the mechanical precision of the gear drive for the transfer cylinders since inaccuracy of only a few thousandths fill of an inch in alignment of the grippers of adjacent transfer cylinders at the moment of transfer is all that is required to destroy an otherwise faultless registration of the sheet. The problem becomes, increasingly difficult as the 2s printing couples and transfer cylinders operating as a unit increase in number since any inaccuracy in transfer is generally cumulative as I regards the registration of the sheet.

In a two-color planographic offset press, for example, it is desirable to space the printing couple's as far apart as possible in order to give adequate drying time for the ink between impressions and to also provide suiiicient space between the printing couples to render the same accessible to the pressmen. However important these considerations may be, they can not be attained by sacrificing accuracy in the registration of the impressions from the succeeding printing couples. This has been a real difficulty. The transfer cylinders of a press of this type are geared to each other and to the several printing couples so that all the parts, operate in unison. It is well known that pressure applied to the gearing at one point, as a result of an opera- 'tion 'on a sheet, is transferred to other parts thereof such as the transfer cylinders and the pressure in many cases has been sufficient to seriously affect the transfer so as to destroy perfect registration of the sheet. Accordingly,

I" an object of the invention is to provide improved rotary sheet transfer means which will assure perfect registry of the successive impression in a multi-color press.

Another object of the invention is to provide rotary sheet transfer members having operation to transfer a sheet from one member to the other and which will effect said transfer in a manner to maintain accurate register of the sheet.

Another object of the invention-resides in the 5 provision of a sheet transfer member having novel means permitting relative movement'between the gripper elements of said member and its driving shaft, whereby said gripper elements may beaccurately aligned with other gripper elements at 10 the moment oftransfer of a sheet to thereby maintain accurate register of the sheet.

A feature of the invention resides in the provision of non-rigid connecting means between each transfer member and its driving shaft where- 15 by each member may have adjustment inde pendently of its driving shaft, such as will produce a circumferential displacement of the gripper elements from their normal position. Advantage is taken of this non-rigid drive by directly con- 20 necting adjacent transfer members during transfer of a sheet, producing displacement of one or both members from their normal position, if necessary, in order to accurately align the gripper elements thereof at the moment of transfer. 25 Thus register of said sheet is maintained and as each transfer may take place through similar mechanism the number of transfers between printing units is immaterial.

Another object of the invention resides in an the provision of transfer means including members each having a non-rigid connection with its driving means and which members will co-act during transfer of the sheet to effect perfect the invention may consist of certain novel features of construction and operation, as will be more fully described and particularly pointed 40 out in the specification, drawings and claims appended hereto.

In the drawings which illustrate an embodiment of the invention and wherein like reference characters are used to designate like parts Figure 1 shows in diagrammatic side elevation the general arrangement of a two color planographic offset press such as may embody the im-' proved sheet transfer means of the invention;

Figure 2 is a plan view of several co-acting transfer members embodying the features of the invention;

Figure 3 is an elevational view taken substantially along line 3-3 of Figure 2 and showing 55 the co-acting gear segments of adjacent transfer members in meshing engagement;

Figure 4 is a. sectional view taken substantially along line 4-4 of Figure 2, showing the manner of journalling the transfer members on their respective drive shaft; and

Figure 5 is an elevational view showing the v invention as applied to a flat bed cylinder press.

Referring to Figures 1 to 4 inclusive, the invention is disclosed as applied to a two-color planographic offset press consisting essentially of a main frame In, preferably made up of two side members and suitable cross members which support the printing couple including a plate or formcylinder II, a blanket cylinder [2, and an impression cylinder [3, all of which cylinders are intergeared so that they will rotate at the same peripheral speed, said gears being identified by numerals [4, I5 and I6, respectively. 1

The printing plate which is attached to the form cylinder by any suitable mechanism is inked by means of inkingmechanism indicated generally by numeral H, which may include the usual ink fountain and,distributing roller, the roller unit, ductor roller for conveying ink from said fountain to said roller unit, and a form roller unit whereby the ink is applied to the printing plate. The cylinder I2 is provided with a resilient surface such as a rubber blanket or the like which receives impressions from the ink plate on the cylinder Ill and transfers said ink impressions to the sheets as they pass between the blanket cylinder l2 and the impression cylinder l3. The sheets to be printed are fed to the impression cylinder (3. In the structure illustrated the sheets are supported by the registering table l8 and transferred from said table to the impression cylinder [3 by stop gripper mechanism carried by shaft 20 to which is fixed gear 2i, the same meshing with gear i6 on the impression cylinder, whereby said stop gripper mechanism has rotation in timed relation to that of said cylinder.

After a sheet has received its impression from the first printing unit it is transferred to the impression cylinder 22 of the succeeding printing unit by means of transfer cylinders 23 driven by gears 30 and which cylinders may embody the improvements of the invention. Upon having received its second impression, which results by reason of the sheet passing between the said impression cylinder 22 and the blanket cylinder 24, the same is then delivered to an endless chain 26, which carries a number of delivery grippers such as 21. It will be observed by reference to Figure 1 that the plate, blanket and impression cylnders of each printing unit are geared together and to the transfer members so that all the cylinders are intergeared for synchronous rotation. The transfer cylinders 23 are uniform in diameter and accordingly the gripper elements on each cylinder will travel at the same peripheral speed. The source of power for rotating said cylinders above described may comprise an electric motor 25 connecting by belt 25 with pulley 21. Said pulley drives the pinion 2B meshing with the gear 30 on the forward transfer cylinder.

While in the prefered form only three .transfer cylinders or members have been shown, it will be readily understood that any desired number of such cylinders or members may be arranged for the purpose of transferring sheets from one printing .unit to another, it being of course understood that each transfer cylinder is provided with gripper elements adapted to engage the sheet and transfer the same when the grippers of the adjacent transfer cylinder are aligned therewith.

In presses of this type it is necessary that the sheet be transferred in a manner to maintain accurate registry for the succeeding ink impressions. An inaccuracy of only a few thousandths of an inch in alignment of the grippers on adjacent transfer cylinders at the moment of transfer is sufficient to destroy an otherwise faultless registration. Such an inaccuracy was unavoidable in machines as heretofore constructed be cause the transfer cylinders were directly connected to the gear driving said cylinder and which gear was included in the chain of gearing connecting the printing units. Thus pressure applied to the gearing at one point, as a result of an operation on the sheet, was transferred to the impression cylinders, for example, to thereby destroy the accurate alignment of the gripper elements at the moment of transfer.

A feature of the invention resides in a nonrigid drive for each transfer cylinder which permits coaction of the cylinders during transfer to eifect perfect alignment of the gripper elements, whereby transfer of the sheet takes place in a manner maintaining accurate register.

Referring more particularly to Figures 2, 3 and 4, a plurality of transfer members are disclosed which may be considered as exemplary of the transfer means in the oifset press shown in Figure 1. The shafts 32, journalled by frame 33, have fixed thereto the driving gears 34 which mesh with each other so that said shafts are driven in unison. Each shaft journals a sleeve 35 to which spiders 35 are suitably fixed at intervals along its length and which spiders have secured thereto, as at 31, the semi-cylindrical member 38. Said member forms the drum of the transfer cylinder. Suitably journalled by the nals a transfer member on its respective driving shaft and thus the transfer member is independent of the shaft and may have rotation with respect to the same. Fixed to each sleeve 35 at the ends is an end member or spider 45 which v has securement to the drum 38 at points 46.

tie rod 41 extends lengthwise of each transfer member and is joined at its respective ends to the end members 45. The drive to each transfer member takes place through an arm 48 suitably fixed to its respective shaft 32 and located exteriorly of and immediately adjacent the end member 45. The outer end of said arm is provided with diametrically opposed portions 49, which portions house springs 50 adapted to engage therebetween the projecting end of a rod 5| extending from end to end of each transfer cylinder and having securement at each end to a member '45. Said rod also connects with the spiders 36 of its respective transfer cylinder as does also the tie rod 41, as will be clear by reference to Figure 4. The arm 48 having connection with the projecting end of rod 5|, through the resilient springs 50, forms a non-rigid connection between the driving shaft 32 and its rement of said gear segment.

The driving shafts of said transfer membersare interconnected by gears 34 and therefore said shafts will rotate in unison. The driving impulse to each transfer member is transmitted by the non-rigid connection described. Accordingly, the transfer members will also be rotated in unison and as the said members are equal in diameter the gripper elements of each will have the same peripheral speed. However, it is possible by reason of said non-rigid connection to produce a circumferential displacement of the gripper elements of a transfer member within limits permitted by said non-rigid connection, and which displacement will take place independently of the gearing connecting the driving shafts 32. Accordingly, it is possible to effect perfect alignment of the gripper elements on adjacent mem bers at the moment of transfer so that said sheet will be transferred in a manner to maintain accurate register of said sheet.

In accordance with the invention this is accomplished by means of gear segments 53, each transfer cylinder carrying a segment and which is secured to the end of a pin 54, projecting from the hub portion 55 integral with the end member 45, the said segment being releasably secured to the pin by nut 56. An opening of suitable size is provided in each gear segment, permitting the gripper shaft 40 of the transfer cylinder to pass through and which also permits possible move- There is secured to the end of the gripper shaft 40 an arm 51 carrying a roller 58 adapted to ride in a cam race formed in the cam member 60 and in this manner the gripper shafts are actuated to open and close at the proper moment for transferring the sheet. The gear segments are positioned on the transfer cylinders so that the pitch line thereof substantially coincides with the periphery of its respective transfer cylinder and it will further be observed that the gear segments are disposed in horizontal-alignment with the gripper elements. During rotation of the transfer cylinders the gear segments on adjacent cylinders have meshing engagement which thereby directly connects the said adjacent transfer cylinders. It is absolutely essential that the gear segments be fixed to the transfer cylinders at a point with respect to the gripper elements thereof so that when the ear segments mesh, proper relative adjustment of the transfer cylinders will result to perfectly align the gripper elements thereof. Even a few thousandths of an inch inaccuracy in alignment of the gripper elements on adjacent transfer cylinders at the moment of transfer is suflicient to destroy the register of the sheet but as a result of the structure of the invention even a relative minor inaccuracy of a few thousandths of an inch can be corrected and the gripper elements perfectly aligned at the moment of trans fer. To insure meshingengagement of the gear segments with a pitch line contact alternate seg-- ments are pivotally secured tothe end members 45 of their transfer cylinder. For example, as shown in Figure 3, the two outer cylinders are pivotally secured in a manner permitting limited oscillating movement with respect to the pin 54; The lower ends of these outer gear segments are yieldingly forced in an outward direction by a coil spring 6| carried by pin 52 secured to the gear segment at one end and having connection at its other end with the end member 45 by means of the boss 63 integral with and projecting from said end member. The tension exerted by said spring may be adjusted by nut 64. When the gear segments are pivotally secured, as in the two outside transfer members, they have a loose connection with the end member at 65. However, with respect to the center transfer member the gear segment thereof-is fixedly secured to pin 54 and is also fixedly secured to the end-member at 65.

By pivotally securing certain gear segments to their respective transfer cylinder and yieldingly forcing the free end thereof outwardly a pitch line contact is assured when adjacent segments mesh during transfer of a sheet. Each transfer cylinder may be described as having a floating relation with respect to its driving means although the driving means will rotate said transfer cylinders in unison. When the gripper elements on adjacentcylinders come together in order to transfer a sheet from one to the other, the gear segments on the respective cylinders will mesh to produce, if necessary, a circumferential displacement of the transfer cylinders in order to accurately align the elements at the moment of transfer. A circumferential displacement is permitted by reason of the floating relation of the cylinders'with respect to the driving means. Actually the displacement of the transfer cylinders in order to accurately align the elements at the moment of transfer may not be more than a few thousandths of an inch but as a. result of the same any inaccuracy in alignment of the gripper elements at the moment of transfer is corrected.

Figure 5 shows the invention as applied to a multicolor flat bed cylinder press. The said press may comprise suitable structure 68 supporting two reciprocating beds 70 and 12. An impression cylinder 13 supported by the driving shaft 14 is adapted to coact with bed 70, while a second impression cylinder 15, supported by shaft I6, is adapted to coact with bed 12. Each cylinder is fixedly secured to its respective shaft and each shaft has suitably fixed thereto, on the gear side of the press, gears TI and 18, respectively. The press shown in Figure 5 is a two revolution, two color type of flat bed cylinder press, an ink impression of one color being applied by cylinder 13 and the bed 10, and a second ink impression of a different color being applied by cylinder 15 and bed 12. For transferring the sheet from. one cylinder to the other a transfer cylinder is interposed therebetween. The driving shaft 8| journals said transfer cylinder so that said cylindermay have rotation relative to its shaft, and arm 48 provides a non-rigid connection between the cylinder and shaft as previously described in connection with the transfer mechanism of Figures 1 to 4 inclusive. Gear 82 is fixed to shaft 8| and is adapted to mesh with gears 11 and 18 so that said impression cylinders have simultaneous rotation with the rotation of the transfer cylinder synchronized to accomplish the transfer of the sheet from one impression cylinder to the other.

The transfer cylinder 80, having floating relation with respect to its driving shaft 8|, carries a gear segment 53 which is pivoted to the cylinder at 54 and is yieldingly forced outwardly at the lower end thereof by the resilient spring 6| in a manner as described with respect to Figures 2, 3 and 4. The impression cylinders 13 and 15 also carry gear segments 53, which, however, are rigidly secured to their respective cylinders at 54 and 65. In operation of the fiat bed press described the sheet is fed from the registering table 84 to the cylinder grippers on the impression cylinder 13 which rotates for a half revolution before said sheet is brought into impression with the reciprocating bed 10 and during the next half revolution or more printing of said sheet takes place. Rotation of the cylinder continues for approximately one-fourth revolution to align the grippers of the cylinders I3 and to transfer the sheet to the cylinder 80 which has rotated so that at the moment of transfer the cylinder grippers thereof are properly positioned. When this takes place the gear segments of the two cylinders have meshing engagement to accurately align the gripper elements thereof. The impression cylinder 13 will rotate for three-fourths of a revolution approximately before another sheet is fed thereto. The transfer cylinder will rotate one and one-half revolutions before locating its cylinder grippers in alignment with the cylinder grippers on the impression cylinder 15. Accordingly, the gear segments of these cylinders will mesh during transfer of the sheet, thereby accurately aligning the gripper elements at the moment of transfer. Rotation of impression cylinder 15 which is in a counter-clockwise direction will eventually bring said sheet into contact with bed 12 to apply an impression to said sheet, whereupon the sheet is eventually taken from said impression cylinder by structure which is not disclosed as the same may be of conventional type old and well known in the printing art.

Theinvention is not to be limited to or by details of construction of the particular embodiment thereof illustrated by the drawings, as various other forms of the device will of course be apparent to those skilled in the art without departing from the spirit of the invention or the scope of the claims.

What is claimed is:

i. In sheet transfer mechanism, members having operation to transfer a sheet from one member to the other, non-rigid driving means for each member, and means on each member having coaction during transfer of the sheet and operative to properly position the members relative to each other, whereby transfer of the sheet] will be efiected in a manner to maintain accurate register of the sheet, the said proper positioning of the members taking place independent- Lv of the driving means therefor.

2. In sheet transfer mechanism, members having operation to transfer a sheet from one member to the other, non-rigid driving means for each member, gripper elements carried by each member for engaging the leading edge of a sheet, and means on each member having coaction during transfer of the sheet and operative toeffect alignment of the gripper elements at the moment of transfer, whereby accurate register of the sheet is maintained, the said aligning'of the gripper elements taking place independently of the driving means therefor.

3. In sheet transfer mechanism, rotary members each having gripper elements for engaging the leading edge of a sheet, driving means for synchronously rotating the members, each driving means having a non-rigid connection with its member whereby the gripper element thereof may be circumferentially displaced from its normal position with respect to its driving means, and means on each member having engagement during transfer of the sheet to directly connect the members, whereby said members are positioned relative to each other to accurately align the gripper elmnents at the moment of transfer.

4. In sheet transfer mechanism, rotary members each ham gripper elements for engaging the leading edge of a sheet, interengaging driving means for synchronously rotating the members, each driving means having a non-rigid connection with its member permitting a circumferentlal displacement of the gripper element thereof from the normal position with respect to its driving means and means on each member adapted to enact during transfer of the sheet, said means having operation to directly connect said members during coaction thereof, whereby said members are positioned relative to each other to accurately align the gripper elements at the moment of transfer.

5. In sheet transfer mechanism, rotary members each having gripper elements for engaging the leading edge of a sheet, driving means for rotating said members in imison, means interposed between each member and the driving means therefor whereby each member has a floating relation with its driving means permitting a circmnferentlal displacement of each gripper element with respect to its driving means, and gear segments on each member having engagement during transfer of the sheet to directly connect the members to accurately align the gripper elements at the moment of transfer.

6. In sheet transfer mechanism, rotary members each having gripper elements for engaging the leading edge of a sheet, driving means for rotating said members in unison, means interposed between each member and the driving means therefor whereby each member has a floating relation with its driving means permitting a circumferential displacement of each gripper element with respect to its driving means, and gear segments on each member constructed and arranged to mesh during transfer of the sheet with a pitch line contact, said gear segments directly connecting the membersto accurately align the gripper elements at the moment of transfer:

'I. In sheet transfer mechanism, rotary cylinders each having gripper elements thereon, driving shafts, means iournalling each cylinder on its driving shaft, a non-rigid connection between each shaft and its respective cylinder, and means carried by each cylinder adapted to coact duringtransferofasheettodirectlyconnectthe cylinders.

8. In sheet transfer mechanism, rotary cylinders each having gripper elements thereon, driving shafts, means Joni-nailing each cylinder on its driving shaft, resilient means interposed in the connection between each shaft and its respective cylinder, whereby each cylinder has a floating relation with its shaft, and means carried by each cylinder adapted to coact during transfer of a. sheet to directly connect the cylinders.

9. In sheet transfer mechanism, rotary cylinders each having gripper elements thereon, driving shafts, means journslling each cylinder on its driving shaft, a non-rigid connection between each shaft and its respective cylinder, and gear segments carried by each cylinder adapted to mesh during transfer of a sheet to directly connect the cylinders.

10. In sheet transfer mechanism, rotary cylinders each having gripper elements, thereon, a driving shaft for each cylinder, a sleeve journaliing each cylinder on its driving shaft, anonrigid connection between each shaft and its respective cylinder, and gear segments carried by each cylinder adapted to mesh' during transfer of a sheet to directly connect the cylinders.

11. In sheet transfer mechanism, members having operation to transfer a sheet from one member to the other, non-rigid driving means for at least one of said members, and means on each member having coaction during transfer of the sheet and operative to properly position the members relative to each other, whereby transfer of the sheet will be effected in a manner to maintain accurate register of the sheet, the said proper positioning of the members taking place independently of the driving means for that cylinder having the non-rigid connection therewith.

12. In sheet transfer mechanism, members having operation to transfer a sheet from one member to the other, non-rigid driving means for at least one of said members, gripper elements carried by each member for engaging the leading edge of a sheet, and means on each member associated with the gripper elements thereof, said means having coactlon during transfer of the sheet to effect alignment of the gripper elements at the moment of transfer, whereby accurate register of the sheet is maintained, the said aligning of the gripper elements taking place independently of the driving means for that cylinder having the non-rigid connection therewith.

13. In sheet transfermechanism, rotary members each having gripper elements for engaging the leading edge of a sheet, driving means for rotating said members in unison, at least one member having a floating relation with its drivng means permitting a circumferential displacement of the gripper elements thereof with respect to its driving means, and gear segments on each member having engagement during transfer of the sheet to directly connect the members to accurately align the gripper elements at the moment of transfer,

14. In sheet transfer mechanism, the combination with spaced impression cylinders having gripper elements thereon, of a rotary transfer cylinder also having gripper elements thereon and 10 located between said impression cylinders, shafts -journalling said cylinders and having a geared relation to rotate the cylinders synchronously, a non-rigid connection between the transfer cylinder and its shaft, and means carried by each cylinder adapted to coact during transfer of a sheet to directly connect the cylinders, whereby the gripper elements thereof are accurately aligned at the moment of transfer.

15. In sheet transfer mechanism, rotary members'each having gripper elements for engaging the leading edge of a sheet, driving means for rotating said members in unison, means interposed between at least one member and its driving means whereby said member'has a floating relation with its driving means permitting a circumferential displacement of the gripp elements thereof, gear segments on each member, the segments on adjacent members having meshing engagement during transfer of the sheet from one member to the other to accurately align the gripper elements thereof at the moment of transfen'and resilient means associated with one gear segment for forcing said segment outwardly to assure a pitch line contact when meshing with the segment on an adjacent member.

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