US3407727A

US3407727A - Supplementary driving gear arrangement for multi-color sheet-fed rotary printing presses

Info

Publication number: US3407727A
Application number: US621293A
Authority: US
Inventors: Fischer Hermann
Original assignee: MAN Maschinenfabrik Augsburg Nuernberg AG
Current assignee: MAN AG
Priority date: 1966-03-23
Filing date: 1967-03-07
Publication date: 1968-10-29
Anticipated expiration: 1985-10-29
Also published as: GB1163205A; DE1296145B

Description

. FISCHER 1 407,727

. 3, SUPPLEMENTARY DRIVIN EAR ARRANGEMENT FOR MULTI-COLOR SHEET-FED ROTARY PRINTING PRESSES v Filed March 7, 1967 INVENTOR Hermann Ham United States Patent 7 Claims. (Cl: 101-177 ABSTRACT OF THE DISCLOSURE A supplementary driving gear is disposed adjacent the intermeshing direct drive gears of the plate, impression and blanket cylinders of multi-color sheet-fed rotary print ing presses with the supplementary gears being provided with a resilient pre-tensioned movement in a direction opposite to the direction of rotation of the cylinders for accommodating the backlash movement in the intermeshing teeth of the direct drive gears therefor, caused by a bead formed on the resilient blanket surface of the blanket cylinders at the point directly in front of the pressure line between the hard surface of the impression and/ or plate cylinders and the soft surface of the blanket cylinders.

This invention relates to multi-color printing on sheetfed multi-color printing presses, and, more particularly to a supplementary gearing arrangement disposed adjacent the direct drive gears in the train of drive between successive stations of the press with this arrangement providing a supplementary gear disposed adjacent the drive gears in the train which supplementary gears are provided with a pre-tensioned resilient circumferential movement in a direction opposite to the direction of rotation of the cylinders to which they are applied for accommodating the backlash between the intermeshing teeth of the various direct drive gears in the train.

This backlash is customarily caused by a bead or swell formed on the'surface of the soft rubber blanket surface of the blanket cylinders at a point immediately preceding the pressure point between the hard surfaces of the impression and/ or plate cylinders and the soft surfaces of the blanket cylinders meshing therewith. This bead formation on the blanket cylinders causes a distortion of the printing on the sheets being fed through the presses in the form of stripes which are commonly referred to in the trade as Princeton stripes. The effect, of course, is to mar the fine quality of the finished image being produced on the sheets being fed through the press caused by a certain amount of distortion at the transfer point between the plate cylinder and the blanket cylinder and between the blanket cylinder and the impression cylinder of a unit of the press and so on with the distortion being caused by this bead formation on the relatively soft surface of the blanket cylinders as opposed to the intermeshing or adjacent hard surface of the impression and/ or plate cylinders.

Thus, the formation of this bead may be caused by minor differences in the diameter of the adjacent impression and plate cyilnders, which, in turn, brings about a difference in development as a result of the positive drive train interconnecting the various cylinders. With the high pressing force necessary for the printing in such presses of the plate and/or impression cylinder which consist of a hard material against the soft rubber blanket of the blanket cylinders, a bead is likely to be formed and thereby cause an uneven running of the entire press through its direct train of driving gears which, in turn, creates the detrimental striping effect on the images being printed.

The head formed is at a point directly in front of the pressure line between the impression and/or plate and the blanket cylinders and has a tendency to attempt to free itself during a revolution and as a result exercises a rearward-turning action against the action of rotation of the two cylinders.

Thus, regardless of the care with which the various printing plates are positioned at the various printing stations to contact the sheets of paper over precisely the same area to provide exact registration. of the several superimposed images or impressions, tooth play between the intermeshing gears caused by the bead formation leads to a change in the flank at the intermesh of these gears and causes a degree of circumferential oscillation of the various cylinders at the point of transfer between the various cylinders which may cause distortion in the form of the so-called Princeton stripes on the resulting printed images.

If it is attempted to correct or compensate for the oscillations caused by such bead formations by arranging one drive gear in the drive train between two adjacent cylinders to have a resilient function or to be disposed in a manner whereby it will have a certain resiliency or give with respect to the corresponding cylinder, the driven cylinder of the two cylinders is prevented from leading the driving cylinder in the direct drive between the two cylinders. However, such an arrangement will not effectively remove the actual bead formation between the two cylinders and will not remove the undesirable formation throughout the entire train of drive in the unit.

Similarly, arranging partial or segmented auxiliary gears adjacent the drive gears which segments are resilient has the effect of removing oscillations in the impression cylinder when it is raised and lowered. However, such an arrangement has no effect upon the bead formation during such time when the two cylinders are pressed together.

According to this invention, however, there is provided in a press an arrangement of supplementary pre-tensioned resilient gears which eliminate the peripheral oscillating of the teeth of the various impression and/or plate and blanket cylinders in the individual units of a multi-unit press. With such an arrangement, the anti-rotational force caused by the bead formation on the soft blanket cylinder surfaces is eliminated, thus eliminating the Princeton striped effect given to the resulting printed images on the sheets of paper passing through the press. This result is obtained by providing adjacent the various intermeshing spur gears in the direct drive train of the various units of the press supplemental adjustable pre-tensioned resilient gears, with the teeth of said supplemental gears cooperating with the adjacent regular spur gears of each cylinder to mesh with the next succeeding spur gears in the chain of drive through a unit of the press. In this manner, both the regular rigid spur gear and the supplemental gear meshes with the spur gear of the next succeeding cylinder and the tooth play or backlash between the intermeshing gears of the two cylinders is prohibited or dampened with the result being that the different cylinders are maintained in register with respect to each other substantially without fluctuations caused by the force of the bead formation on the soft surface of the blanket cylinder. With such a construction, the undesirable Princeton stripe effect is eliminated or minimized with the images imprinted on the sheets passing through the press.

With the foregoing and additional objects in view, this invention will now be described in more detail, and other objects and advantages thereof will be apparent from the following description, the accompanying drawings, and the appended claims.

In the drawings:

FIG. 1 shows a side elevation of an impression cylinder drive gear and having this invention applied thereto;

FIG. 2 is a section along the line II1I of FIG. 1;

FIG. 3 is a simplified diagrammatic top view indicating further aspects of the arrangement of the mechanism of FIG. 1;

FIG. 4 is a simplified diagrammatic enlarged top view indicating another embodiment of the arrangement of mechanism of FIG. 1; and

FIG. 5 is a diagram showing a portion of a printing unit in a multi-unit printing press in side elevation.

Referring to the drawings, in which like reference characters refer to like parts throughout the several views thereof, an arrangement of apparatus embodying and for practising this invention is illustrated as being applied to the direct drive gear train between the cylinders of the printing stations of a sheet-fed printing press, which mechanism is for providing the driving from one cylinder of the press unit through the blanket cylinder thereof to another cylinder of the unit and so on. Since such driving and gearing mechanism of multi-unit printing presses is well known and understood in this art, the drawings are primarily directed to illustrating the application of this invention to such otherwise well known or conventional printing press arrangements, and many of the constructional elements of the printing press and the impression and/ or plate cylinder have been omitted from the drawings for clarity and simplicity.

Thus, FIG. 5 shows a plate cylinder 10, blanket cylinder 11, and an impression cylinder 12 of a printing unit of a multi-unit printing press. Impression cylinder has a spur gear 13 (shown diagrammatically in FIG. 3) disposed thereon and intermeshing with spur gear 14 on cylinder 11 which in turn meshes with spur gear 15 on cylinder 12. In this connection, and as noted above, a bead W may form on the blanket cylinder 11 which, with only the slightest tooth play between the various intermeshing drive gears, exerts a rearward-turning or antirotational action on the drive gear of the cylinder 12 which is driven by the gear on the cylinder 11, with the result being an uneven running between the two cylinders.

In order to prevent this from happening, and as noted above, a supplementary gear 18 is disposed coaxially adjacent the drive gear 13 for the cylinder 10 (FIG. 2). This supplementary gear 18 is rotatable circumferentially with respect to the adjacent drive gear 13 and is supported against that gear by one or more springs 19 (FIGS. 1 and 2), with only one spring arrangement being shown for the purposes of illustration and for clarity. The spring is disposed on a pin 20 which, in turn, is screwed into the head 21 of screw 22 (FIG. 2), which screw 22 has an axis parallel to the axis of the cylinder to which it relates.

The other end of spring 19 rests against disc 23 which is pressed against the end surface of recess 24 in the auxiliary gear 18. This spring arrangement is disposed, as is well understood, with consideration for the direction of rotation of the gears, as is indicated in FIG. 1 by the arrow 25. Further, an adjusting nut 28 is disposed on pin 20. As will be understood, therefore, by adjusting the nut 28, the spring force of spring 19 can be so varied as to cause supplemental gear 18 to rotate circumferentially thus causing the teeth disposed thereon to move against the opposing flanks of the teeth of the next succeeding intermeshing spur gear so as to act against the force caused by the rubber bead and as a result, therefore, the undesirable force caused by the rubber bead is counteracted.

As mentioned above, this invention is not limited to the use of such a supplemental resilient gear on only the plate cylinder. Not only can the supplemental gears be used to remove the bead formation on the blanket cylinder as it relates to the plate cylinder, but also on the blanket cylinder as it relates to the impression cylinder 12 as well.

FIG. 3 shows a simplified diagrammatic top view of the gearing arrangement of

cylinders

10, 11, and 12 in accordance with this invention. That is, plate cylinder 10 has a drive gear 13 disposed thereon with the supplemental resilient gear 18 being disposed adjacent thereto and with both the rigid drive gear and the resilient gear being in intermeshing relationship with the drive gear 14 of blanket cylinder 11. Direct drive gear 14 of blanket cylinder 11 has disposed adjacent thereto a supplemental gear 29 in a manner corresponding to the

gears

13 and 18 of plate cylinder 10. These two related gears of blanket cylinder 11 are in turn both disposed in intermeshing relationship with the direct drive gear 15 of impression cylinder 12, thus providing the counteracting force necessary for eliminating the disadvantages of the bead formation on blanket cylinder 11 at the pressure point between cylinder 11 and cylinder 12.

FIG. 4 shows another embodiment of apparatus for practising this invention with a different arrangement of spur and resilient supplemental gears. In this embodiment, the direct drive gear 13 of the plate cylinder 10 has no supplemental resilient gear disposed adjacent thereto. However, direct drive gear 14 of cylinder 11 has a supplemental gear 30 disposed thereon with both the direct drive gear 14 and the resilient supplemental gear 30 being in intermeshing relationship with the direct drive gear 13 of plate cylinder 10. Further, the direct drive gear 15 of cylinder 12 has a resilient supplemental gear 31 disposed adjacent thereto, with both

gears

15 and 31 being in intermeshing engagement with direct drive gear 14 of cylinder 11.

As will be noted in both of the embodiments of FIGS. 3 and 4, a resilient supplementary gear is always in engagement with a direct drive gear of the next succeeding cylinder while, at the same time, no resilient supplementary gear is in engagement with another resilient gear. Further, two supplementary gears suffice to control the bead formation in the three cylinder arrangement. Obviously, with such an arrangement of supplementary and direct drive gearing in the direct drive of the unit, the objectionable anti-rotational force caused by the bead formations on the blanket cylinders is eliminated by imparting a counteracting force to this undesirable anti-rotational force, and, therefore, eliminating the oscillations between the various intermeshing teeth of the direct drive train. Further, since each supplemental gear can be adjusted individually by operating its own set screw 28, the tooth clearances, which may be different for each set of intermeshing gears in the gear train drive and which may have different distances from cylinder to cylinder are accommodated for, thus eliminating the objectionable oscillation of the spur gear drive at the transfer point from cylinder to cylinder in a unit of the press.

Obviously, the invention is not limited to the field of application described above as relating to a multi-unit sheet-fed rotary printing press, but can also be used in other applications utilizing gear drives having an objectionable oscillation and in which correction is necessary in order to counteract a counter-rotational force caused by such things as a slight difference in the diameters of two adjacent cylinders being driven by the direct drive gear train, or in any use where two cylinders might be r0- tating against each other and in which an undesirable bead formation is formed on one or more surfaces due to the pressing force between the two cylinders.

Thus, there is provided in accordance herewith structures and arrangements in a multi-unit sheet-fed rotary printing press having a direct gear drive from one unit thereof to the next for accommodating individually objectionable oscillation at the intermesh between the individual gears of the drive caused by bead formation on the soft surfaces of the blanket cylinders at the pressure point between the hard surfaces of the plate and/ or impression cylinders, thus eliminating the oscillations by counteracting the anti-rotational forces caused by such bead formations, and, in turn, providing accurate registering of the images to be printed on the sheets. With such an arrangement, each sheet is presented individually at each printing station in precise registry so that the printed image thereon coincides exactly as desired with the previously or subsequently printed area of the sheet to obtain the desired final composite multi-color printed image on the sheet with no so-called Princeton stripes disposed thereon notwithstanding distortions caused by said bead formations which in turn are caused by variations or differences' in the development of rotation of two adjacent rotating cylinders having minor differences in diameter. In addition, different variations causing different amounts of oscillation between the intermesh of the individual gears in any particular printing station or unit can be accommodated for individually without regard to different variations in the inter-mesh of other intermeshing gears in the train so as to provide complete and individual elimination of the different degrees of oscillation at the various transfer points between the various plate and/or impression cylinders and the adjacent blanket cylinders in the drive which brings about smooth running throughout the entire press.

As apparent from the foregoing, the arrangements of apparatus provided in accordance herewith are readily and simply supplied, and are similarly simply applicable, as will be understood, to any similar mechanism having a direct drive arrangement in which the individual gears thereof may have slight deviations in the teeth clearances between them which cause undesirable oscillation along the various units of the drive.

While the arrangements of structures and apparatus herein described constitute the preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise structures and apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. In multi-color sheet-fed rotary printing press apparatus of the character described having a plurality of printing stations for imprinting sequentially a series of images on sheets fed therethrough to form a final composite multi-color image on said sheets, and having at least one plate cylinder, one blanket cylinder and one impression cylinder at each station thereof for imprinting said images on said sheets, with each of said plate, blanket and impression cylinders having a spur gear disposed on the shafts thereof and intermeshing with each other to form a drive gear train from a source of power through said plurality of stations, the combination which comprises a supplemental pre-tensioned resilient gear rotatably disposed selectively axially adjacent the spur gears on the shafts of each of said plate and said blanket cylinders and each of said impression and said blanket cylinders, means connecting each of said supplemental gears to its respective adjacent spur gear for holding said supplemental gears against rotation, resilient means disposed between said connecting means and said supplemental gears for maintaining said supplemental gears resiliently disposed with respect to the adjacent spur gears circumferentially around the shafts of the said cylinders, and adjusting means disposed on said resilient means for selecting the degree of tension of said resilient means against such supplemental gears.

2. Apparatus as described in claim 1 in which said connecting means includes at least one recess disposed in said supplemental gear, a screw threaded into the said adjacent spur gear with the head thereof extending into said recess, and a pin disposed in said recess and extending from the edge of said recess to the head of said screw.

3. Apparatus as described in claim 2 in which said resilient means includes a disc disposed at one end of said recess for holding one end of said pin and said recess, and a spring disposed on said pin and extending from said disc to the head of said screw for imparting a circumferential resilient movement to said supplemental gear with respect to the adjacent spur gear therefor.

4. Apparatus as described in claim 3 in which a nut is disposed on said pin and adjacent said spring, whereby turning said nut adjusts the degree of tension of said spring and the resilient action of said supplemental gear.

5. Apparatus as described in claim 2 in which said resilient means and said adjusting means are disposed in said recess to impart said resilient action against said supplemental gear in a direction opposite to the direction of rotation thereof.

6. Apparatus as described in claim 1 in which said resilient means and said adjusting means include adjustable spring means disposed between said connectig means and said supplemental gear for imparting a pro-selected resilient tension on said supplemental gear with respect to the said adjacent spur gear.

7. Apparatus as described in claim 1 in which said supplemental gears are axially offset from each other and in which one of said supplemental gears is in driving engagement with the said spur gear not having a. supplemental gear disposed adjacent thereto.

References Cited UNITED STATES PATENTS 2,607,238 8/1952 English et al. 74-440 2,845,860 8/1958 Mestre l01-177 3,035,454 5/1962 Luning 74-440 3,174,356 3/1965 Michalec 74-440 2,245,303 6/1941 Shane. 1,506,820 9/ 1924 Erdman et al. 2,743,475 5/1956 MacNerland.

FOREIGN PATENTS 877,646 2/1961 Great Britain.

ROBERT E. PULFREY, Primary Examiner. J. R. FISHER, Assistant Examiner.