US2694941A

US2694941A - Adjustable gearing

Info

Publication number: US2694941A
Application number: US253892A
Authority: US
Inventors: William R Spiller
Original assignee: Harris Seybold Co
Current assignee: Harris Corp
Priority date: 1951-10-30
Filing date: 1951-10-30
Publication date: 1954-11-23
Anticipated expiration: 1971-11-23

Description

Nov. 23, 1954 sp 2,694,941

ADJUSTABLE GEARING Filed Oct. 30, 1951 [I HHIHHH 3 Sheets-Sheet 2 'ITFF I HrTaQ/v 6 Nov. 23, 1954 w. R. SPILLER ADJUSTABLE GEARING 3 Sheets-Sheet 3 Filed Oct. 30, 1951 INVENTOR. W/Ll/fl/V E. JIO/ZZER ZZZ Arm/9N5) United States Patent fitice 2,694,941 Patented Nov. 23, 1954 I ass'ignor to Cleveland, Ohio, at corpora- This invention relates to rotary oilsetp'ri more particularly to multicolor olfse't'rnac for controllably vaiyinig the length of printin single'unit machine or in the individual units of a inult iunit machine from plates of fixed length.

in offset printing, 7 to prevent the nomprintin'g areas of the plate from taking the greasy ink. More or less of this moistureistakenefl the plate by the blanket cylinder and thus transmitted to the paper as the latter travels through the line of tangency between the blanket and impression cylinders. With each such absorption of moisture the aper expands or grows. Hence af-te'r a paper sheet passes throu h the first'unit of 'a multiun'it machine the length of the print is longer by a small amount than'the length of the image on the plates of the various units, and it becomes necessary in order to get good register -'throughout the length of the image to lengthen the'pririt in the'next unit by thatemount. In each of the succeeding units a similar growth orexpansion of the pa e'roecurs and must be compensated by a lengthening of the print over that of the preceding unit. This has been accomplished conventionallyformany years by varying the packing on the blanket or plate cylinders or both, which is a hit or miss method re'quiring considerable skill "and one that is time consuming at best.

The presentinvention is directed to the provision-of adjustable mechanical means for producing a gradual illcease or decrease in speed between the blanket cylinder and one of the cooperating c linders, that is the plate or impression cylinder, during the printing portion of the cycle, and for returning the cylinders to their original angular relation during the gap portion of the cycle. 'One method heretofore followed in four color printing machines is to shorten the print in the first unit, "make its length uniform with that of the plate in the second unit-and increase its len'gthsu'ccessively in-each ofthe tWo remaining units.

In some respects the present invention may be considered to be an impovernent upon the invention disclosed in thecopending application of Charles W. Harrold, Serial No. 693,554, :filed August .28, 1946, now Patent No.

2,619,901., dated December 2, 1952.

One of the objects of the invention "therefore is "the provision of mechanism for adjustably increasing or decreasing the length of print in a given unit as compare'dwith the length of image on the platecylinder.

Another object is the provision of means of the character stated in which the operating parts shall travel a substantial distance in effecting the necessary small variations in angular speed between two cooperating cylinders, whereby lubrication problems are simplified.

A further object is the provision of rnean's of the character stated which shall be smooth and quiet in operation and in which adjustments may be effected quickly and accurately.

Other objects and features of novelty will appear as I proceed with the description of that embodiment of the invention Which, for the purposes of the present application, l have illustrated in the accompanying drawings, in which:

Fig. 1 is a fragmental elevational View partly in "section showing two cooperating cylinders, in this case the impression and blanket cylinders, of a rotary -offset printing machine to which the invention is applied, the blanket cylinder being swung into vertical alignment with the impression cylinder to more clearly illustrate the inventl'on.

dampening means must hesruployed Fig. Z' -is a diagrammatic view of the gearing connections for the three cylinders of a printing unit-shown theircorrect relative positions.

Fig. 3 is a detail view on a larger scale showing the print control mechanism, the View being taken substantially on the line-3-3'ofjFig. l'or Fig. 5.

Fig. 4 is a trag'mental top plan 'view'off the impresision cylinder with the print control mechanism also in top plane view. V

Fig. 5 is a fr'a'gmch'tal viewpartly in side elevation'and partly in section on an irregular 'line '55 indicated in Fig. 3, and I Fig. '6 is a diagrammatic view illustrating the cam track in dilferent positions of adjustment. 7

Referring to Fig. 2 'platea'nd 'blanketgears 1i) and 1E respectively are shown in mesh, These gears are fixed with respect to the plate and blanket cylinders, which cylinders ordinarily have bearers the surfaces of which correspond with the pitch lines of the gears, so that the angular-speed of these two cylinders is "the same. Gear 12 which meshes with gear 11 is concentric with th'e pression cylinder 13, but is mounted "to be capable of slight oscillation with respect to that cylinder while tu'rning with it, as will presently appear. To hold the gear in position axially of shaft 15, a plurality of studs 52 with spacers 53 extend through holes 54 in the gear'weba'nd are threaded into tapped holes in the cylinder 13. The heads ofthe studs 52 bear through washers '55 against spacers 5 3 and the washers loosely engage bosses 56 on the gear thereby permitting its oscillation through a small angle V The three cylindersreferred to may constituteall of the cylinders of a single color press, or the cylinders of an individual unit in a muticolo'r press. it is n cessary i to be able to control "print length not only in the case of a multicolor press for reasons above stated, but also in a single color press when it is used for printing two or more diiierent colors in successive passes of a pile'of sheets through the machine. V

The three cooperating cylinders 'of a unit each have shafts which are journaled in the side frame members of the machine, although in the drawings there is illustiated only a fragment of the frame member 14on fthe gear side of the machine and the shaft l'Sfor the impression cylinder 13. On the outer side of frame member 14 this shaft carries a gear 16 which meshes with a gear, not shown, that is driven directly or indirectly by a prime mover, also not shown. I The impression cylinder therefore turns at constant speed. Gear 12 has a'rotative bearing on shaft 13 inwardly of the it the member 14, and the adjustable "control mechanism of this invention is used to revolve it with the cylinder either at the same speed as the cylinder or at varying speeds in a given revolution or cycle. Since the blanket cylinder gear 1-1 meshes with gear 12 and the plate cylinder gear 10 meshes with gear 11, the plate and blanket cyhn'derspartake of the speed variations imposed upon the gear 12.

The blanket cylinder is shown fragmentally in Fig. l at 17. in accordance with conventional practice it is covered with a resilient rubber blanket which ro'lls upon the paper sheets that arebo'rn'e by the impression cylinder. In the gap 18 of the impression cylinder are mounted sheet grippers 32 of conventional form operated in a conventional manner. I

On the inner side of the frame member 14 there is a cam 19 which surrounds shaft 15 and is hired upon the inner surface of the frame. It may be secured to the frame by suitable means such as machine screws '20 threaded into a ring 21 which may servealso to hold "a lubricant retainer 22 surrounding the shaf t. on the perimeter of this cam there r'uns a roller follower 23 carried at one end of a lever '24 which is pivotally mounted intermediate its ends in a boss '25 formed in the web of gear 12. For this purpose a stub shaft 26 may be fitted tightly within a bore in the lever and this shaft may be journa'led in a pair of 'ball bearings '27, the outer races of which fit within a bore 28 in the boss 25. A round washer 2'9 anchored to the inner endfof shaft 26 by a screw '30 bears against the inner race of one'of the bearings to hold the shaft against longitudinal movement outwardly. A cavity 31 formed at the end of the cylinder accommodates the

parts

29 and 30. Lever 24 on the side of its pivot 26 remote from follower 23 carr1es another follower 33 which extends inwardly from the lever. Follower 33 is the outer race of a ball bearing, the inner race of which is mounted on a stud or bolt 64 mounted in the lever. This follower runs wlthin a cam track 34 formed in a block 35 which is carried by the end of the cylinder and projects forwardly therefrom through an opening 36 in the web of gear 12. In the illustrated case the cam track 34 is arcuate.

37 is a short post the rear portion of which 1s of somewhat constricted diameter and is press fitted into a bore 38 in cylinder 13. Block 35 is rotatably mounted on the forward portion of post 37, being held against longitudinal movement by a washer 39 which 1s secured to the outer end of the post by screw 40.

Block 35 has an integral arm a substantially radial direction, by means of which the block 35 may be adjusted angularly about its pivot post 37. Adjusting screw 42 mounted in a post 43 carried by the cylinder bears against arm 41 and screw 44 mounted in a post 45 also carried by the cylinder bears upon the opposite side of the arm. By means of these screws the position of the arm and the consequent angular posttion of block 35 may be changed as required. For locking the arm in adjusted position a lock screw 46 1s threaded into arm 41. It extends through a slot 47 in a flange of the cylinder and has a head 48 which bears against the flange when the screw is tightened. The follower 23 is held against the perimeter of cam 19 by a compression spring 49 surrounding a rod 50 whlch is mounted at one end in an angled plate 51 that ispivotally connected at 57 with the gear 12 near the periphery of the latter. Spring 49 bears at one end against a nut 58 threadably mounted on the rod and held in adjusted position by a lock nut 59. At its other end it bears against a collar 60 having trunnions 61 that are mounted in bifurcations 62 of lever 24. Rod 50 is slidably mounted in a bore extending through collar 60 and is prov1ded with a screwdriver slot at its free end so that it may be turned relative to

nuts

58, 59 for adjustment of spring 49, its connection with plate 51 being such as to permit rotation.

Assuming that the cam track 34 in block 35 is arcuate, as herein illustrated, the median line 65 of the arcuate path of this track or groove passes through the axis of post 37, as indicated in Fig. 6. The distance between axis 66 of lever pivot 26 and axis 67 of post 37 is the same as the radius of the median arcuate path 65. When the center of this radius, indicated at 68 in Fig. 6, coincides with the axis 66 of lever pivot 26 the movements of follower 33 back and forth in cam track 34 have no elfect upon the rotation of gear 12 and it turns at the same constant speed as cylinder 13. When however arm 41 is moved from its full line position of Fig. 6 to cause radius 68 to be shifted to one side or the other of its central position as indicated in Fig. 6, the center of the radius of the arcuate path 65 is shifted to one side of the other of the axis 66 of lever pivot 26, whereupon the follower 33 as it swings back and forth in response to the action I of fixed cam 19 causes gear 12 to travel with speeds varying positively and negatively during each cycle. If it is desired to make the print longer than the plate image, arm 41 is shifted to the left as viewed in Fig. 6 to the position indicated at X for example. Then in the operation of the mechanism when the follower 33 is forced outwardly from the gear center the gear will be caused to rotate slightly counterclockwise with respect to the cylinder. Conversely, adjustment of the cam track clockwise to the position indicated at Y for example will cause the gear 12 to rotate clockwise with respect to the cylinder when the follower 33 is forced outwardly. The magnitude of the displacement between the gear and the cylinder is controlled by the adjusted eccentricity of the cam track, that is the degree to which the center of the radius of its arcuate path is shifted away from the axis 66 of the lever pivot.

The profile of fixed cam 19 is so made that the rate of rotational displacement between the gear and the cylinder is substantially uniform during the printing portion of the cycle. The cam profile also causes the gear to return to its original angular relation with respect to the cylinder while the gripper gap 18 of the impression cylinder passes the blanket cylinder. The gear drives the blanket cylinder. Hence the original angular positions 41 projecting outward in 4 of the impression and blanket cylinders is resumed at the beginning of each printing portion of the cycle.

The angular increase or decrease of travel of the gear 12 with respect to the cylinder 13 in order to compensate for paper growth varies somewhat with the grade of the stock, atmospheric conditions, etc., but is relatively small, that is to say of the order of ,452 inch with average size sheets under average conditions. The travel of the follower 33 in the cam track 34 to effect this displacement however is quite substantial and difficulties of lubrication which might present themselves otherwise are not present.

The form of adjustable cam track shown in the drawing and described above is preferred, because it is possible to so adjust it that the speed of the impression and blanket cylinders remains constant and equal throughout each cycle. However under some circumstances it may be desirable to employ a cam track that is straight or that follows a curve other than an arcuate one, as for example when it is desired to cause a given difference in angular speed of two cylinders to be maintained precisely uniformly throughout the printing portion of the cycle, or to accomplish some other special result.

Having thus described my invention, I claim:

1. In a printing machine of the character described, two coaxial elements, namely a cylinder and a gear, said elements being capable of limited relative oscillation while rotating, power means for driving one of said elements, a fixed cam surrounding the axis of said elements, a lever pivotally mounted on one of said elements, a follower carried by said lever running on said fixed cam, an arcuate cam track spaced from the lever pivot and mounted on the second element, and a second follower carried by said lever running on said cam track, said cam track being adjustable to a position crossing the arc of movement of said second follower, whereby the speed of rotation of one of said elements is varied positively and negatively during each cycle by the oscillation of said lever due to the action of said fixed cam.

2. A printing machine as described in claim 1, wherein said cam track is formed in a block, a pivot carried by said second element upon which said block is mounted, and means for adjusting said block angularly about its pivot.

3. A printing machine having two coaxial elements as defined in claim 1, wherein the radius of curvature of the center line of said arcuate cam track is equal to the distance between the lever pivot and the axis of said second follower.

4. In a printing press, means for controlling the length of print, comprising two coaxial elements, namely a cylinder and a gear, means for driving said cylinder, said gear turning with said cylinder but capable of limited oscillation with respect thereto, a fixed cam surrounding the axis of said driven cylinder, a lever pivo tally mounted on said oscillatable gear, a follower carried by said lever running on said fixed earn, an arcuate cam track mounted on said driven cylinder, and a second follower carried by said lever running on said cam track, said cam track being adjustable to a position crossing the arc of movement of said second follower, whereby the speed of rotation of said oscillatable gear is varied positively and negatively during each cycle by the oscillation of said lever due to the action of said fixed cam.

S. A printing press embodying a length of print control mechanism as defined in claim 4, wherein said cam track is formed in a block and the means for adjusting said cam track embodies a pivot carried by said drlven cylinder upon which said block is mounted, the center of said pivot being on the median line of said arcuate track, and means for adjusting said block angularly about said pivot.

6. A printing press as defined in claim 4, wherein the radius of curvature of the center line of said arcuate cam track is equal to the distance between the lever pivot and the axis of said second follower.

7. A printing press embodying a length of print control mechanism as defined in claim 4, wherein said arcuate cam track is formed in a block, said means for adjusting said cam track embodying a pivot carried by sald driven cylinder upon which said block is mounted, an arm integral with said block, and adjustable stops carried bysaid driven cylinderon. opposite: sides; of said arm for holding the: block-in different angular positions about said-pivot. ,v

8. In a printing press, a length. of printfcontrol. comprising two coaxial elements, namely a cylinder and a gear, means for driving said cylinder, said gear turning with said cylinder but capable of limited oscillation with respect thereto, a. fixed cam surrounding the axis of, said driven cylinder, a lever pivotally mounted intermediate its ends on said oscillatable gear, a follower carried. on one end of said lever running on said fixed. earn, an arcuate cam track mounted. on said driven cylinder, a second follower on the other end of said lever running on said cam track, the median arcuate. path of said. cam track having a radius equal to the distance between the axis of the lever pivot. and. the axis of said second follower, and means for adjustingsaid cam track angularly to cause the radius of said arcuate path to cut the axis of the lever pivot or to be displaced laterally on either side of said pivot axis, whereby said oscillatable gear revolves either at constant speed with said driven cylinder or at speeds varied positively and negatively during each cycle with. either the. increase or the decrease coming first in the cycle..

9. A printing press. embodying a length of print control mechanism as defined in claim 8', wherein said arcuate cam track is formed in. a block and wherein said means for adjusting said cam track comprises a pivot carried by said driven cylinder upon which saidblock is mounted, and means for adjusting said block angularly about said pivot.

10. A printing press embodying a length of print control mechanism as defined in claim 8, wherein said arcuate cam track is formed in a block and wherein the means for adjusting said cam track embodies a pivot carried by said driven cylinder upon which said block is mounted, an arm integral with said block, and adjustable stops carried by said driven cylinder on opposite sides of said arm for holding the block in different angular positions about said pivot.

11. In a printing press, a length of print control com prising two coaxial elements, namely an impression cylinder and a gear turning therewith but capable of limited oscillation with respect thereto, a lever pivotally mounted on said oscillatable gear, a fixed cam surrounding the axis of said impression cylinder, a follower carried by said lever running on said cam, an arcuate cam track mounted on said impression cylinder, a second follower on said lever running on said cam track, the median arcuate path of said cam track having a radius equal to the distance between the axis of the lever pivot and the axis of said second follower, and means for adjusting said cam track angularly to cause the center of the arc of said arcuate path to coincide with the axis of,

the lever pivot or to be displaced laterally on either side of said pivot axis, whereby said oscillatable gear revolves either at constant speed with said impression cylinder or at speeds varying positively and negatively during each cycle with either the increase or decrease in speed coming first in the cycle.

12. A printing press embodying a length of print control mechanism as defined in claim 11, wherein said arcuate cam track is formed in a block and wherein the means for adjusting said cam track comprises a pivot carried by said impression cylinder upon which said block is mounted, and means for adjusting said block angularly about said pivot.

13. A printing press embodying a length of print control mechanism as defined in claim 11, wherein said arcuate cam track is formed in a block and wherein said means for adjusting said cam track comprises a pivot carried by said impression cylinder upon which said block is mounted, an arm integral with said block, and adjustable stops carried by said impression cylinder on opposite sides of said arm for holding the block in different angular positions about said pivot.

14. In a printing press, a length of print control comprising two coaxial elements, namely a driven cylinder and a gear turning therewith but capable of limited oscillation with respect thereto, a fixed cam surrounding the axis of said driven cylinder, a lever pivotally mounted intermediate its ends on the outer side of said oscillatable gear, a follower carried on one end of said lever running on said fixed cam, said oscillatable gear having an opening through its web, a block pivotally mounted the axis of said driven cylinder,

on said driven cylinder projecting into saidopening, a earn track formed insaid block, and a second follower mounted: on, the: other end of 'd lever and projecting inwardly therefrom, into. said cam. track, said cam track being adjustable. to cause the mecfian line thereof to cross the arc of movement: of the. second. follower on either side thereof, whereby said oscillatable. gear revolves at speeds; varying positively and negatively during each cycle with either the increase or decrease in speed coming first in the. cycle.

15. In: a printing press, a. length of print control comprising. two coaxial elements, namely a driven cylinder and a. gear turning therewith and capable of limited oscillation. with respect thereto, a fixedcam surrounding a lever pivotally mounted intermediate its ends on the outer side of said oscillatable gear, a follower carried on one. endof said lever running on said fixed cam, saidoscillatable gear having an opening through. its web, a block pivotally mounted on said driven cylinder and projecting into said opening, an arcuate cam track formed in said block, a second follower mounted on the other end of said lever and projecting inwardly therefrom into said cam track, the median arcuate path of said cam t-rack having a radius equal to the distance between the axis of the lever pivot and the axis of said second follower, and means for adjusting angularly the said cam track to cause the center of said arcuate path to coincide with the axis of the lever pivot or to be displaced laterally on either side of said pivot axis, whereby said oscillatable gear revolves either at; constant speed with said driven cylinder or at speeds varying positively and negatively during each cycle with either the increase or decrease in speed coming first in the cycle.

16. In a printing press, a length of print control comprising two coaxial elements, namely a driven cylinder and a gear turning therewith but capable of limited oscillation with respect thereto, a fixed cam surrounding the axis of said driven cylinder, a lever pivotally mounted on said oscillatable gear, a follower carried by said lever running on said fixed cam, an arcuate cam track mounted on said driven cylinder, the center of the arc of said arcuate track being disposed to one side of a radius of the cylinder passing through the cam track but spaced somewhat from the axis of the lever pivot, and a second follower on said lever running on said cam track, whereby the speed of rotation of said oscillatable gear is varied positively and negatively during each cycle by the oscillation of said lever due to the action of said fixed cam, and whereby the relative movement between said second follower and said cam track is large compared to the difference in angular movement of said cylinder and said gear.

17. In a printing press, a length of print control comprising two coaxial elements, namely a driven cylinder and a gear turning therewith but capable of limited oscillation with respect thereto, a fixed cam surrounding the axis of said driven cylinder, a lever pivotally mounted intermediate its ends on said oscillatable gear near the periphery thereof, a follower carried on one end of said lever running on said fixed cam, a cam track mounted on said driven cylinder near the periphery thereof, and a second follower on the other end of said lever running on said cam track, said cam track being adjustable to cause the median line thereof to cross the arc of movement of the second follower on either side thereof, whereby said cam track in all positions of adjustment lies at an acute angle to any radius of the gear passing through it.

18. In a printing press, a length of print control comprising two coaxial elements, namely a driven cylinder and a gear turning therewith but capable of limited oscillation with respect thereto, a fixed cam surrounding the axis of said coaxial elements, a lever pivotally mounted intermediate its ends on one of said coaxial elements near the periphery thereof, a follower carried on one end of said lever running on said fixed cam, a cam track mounted on the other of said coaxial elements near the periphery thereof, and a second follower on the other end of said lever running on said cam track, said cam track being adjustable to a position crosswise of the arc of movement of said second follower, whereby said cam track in all positions of adjustment on its coaxial element lies at an acute angle to any radius of the element passing through the cam track.

19. In a printing press, a length of print control comprising two coaxial elements, namely a driven cylinder and a gear turning therewith but capable of limited oscillation with respect thereto, a fixed cam surrounding the axis of said driven cylinder, a lever pivotally mounted intermediate its ends on said oscillatable gear near the periphery thereof, a follower carried on one end of said lever running on said fixed cam, an arcuate cam track mounted on said driven cylinder near the periphery thereof, a second follower on the other end of said lever running on said cam track, the median arcuate path of said cam track having a radius equal to the distance between the axis of the lever pivot and the axis of said second follower, and means for adjusting angularly the said cam track to cause the center of said arcuate path to coincide with the axis of the lever pivot or to be displaced laterally on either side of said pivot axis, whereby said cam track in all positions of adjustment lies at an acute angle to any radius of the gear passing through it.

20. In a printing press, means for controlling the length of print comprising two coaxial elements, namely a cylinder and a gear, means for driving said cylinder, said gear turning with said cylinder but capable of limited oscillation with respect thereto, a lever pivotally mounted on said oscillatable gear, means for imparting a pivotal movement of predetermined angularity to said lever during each rotation of the cylinder and gears, a cam track mounted on said driven cylinder and a follower carried by said lever running on said cam track, said'cam track being adjustable to a position crossing the arc of movement of said follower whereby the speed of rotation of 8 said oscillatable gear is varied positively and negatively during each cycle by the oscillation of said lever.

21. In a printing press, means for controlling the length of print comprising two coaxial elements, namely a cylinder and a gear, means for driving said cylinder, said gear turning with said cylinder but capable of limited oscillation with respect thereto, an arcuate cam track mounted on said driven cylinder, and means on said gear moving in an arcuate path to ride on said track during each rotation of the cylinder and gear, said cam track being adjustable to a position crossing the arcuate path of the means riding thereon, whereby the speed of rotation of said gear is varied positively and negatively during each cycle.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 908,267 Jacobson et al Dec. 29, 1908 1,128,351 Motley Feb. 16, 1915 1,721,408 Perdreau July 16, 1929 1,807,889 Belin June 2, 1931 1,858,763 Chase May 17, 1932 2,199,561 Fuller et al. May 7, 1940 2,360,340 Harris Oct. 17, 1949 FOREIGN PATENTS Number Country Date 546,757 Germany Mar. 3, 1932