US1777883A - Press - Google Patents

Description

Patented Oct. 7, 1930 UNITED STATES PATENT OFFICE nownnn L. EETHERINGTON, or lvnwronnon, CONNECTICUT, ASSIGNOR TO THE BAB- Application filed May 23,

My invention relates to presses, and more particularly to the bearersuassociated. with the printing elements of the press. In a two revolution'fiat bed printing press the impres sion cylinder is'in contact with the bearers on the bed only during-the printing stroke,

and when the cylinderismoved down into position ready for the printing stroke, the

of raising or lowering the cylinder is actually-taking place. In a rotary press, however,

where the impression cylinder and formcylinder are both rotary members, the bearers, which are the memberswhichcome into direct contact and are arrangedat theends of the cylinder,-are round thatflis to' say,

they extend completelyaround the circumference of the cylinder as heretofore constructed. It will be apparent that as theimpression cylinder is moved toward the form n cylinder to bring about the printing relation,

the bearers will be in contact with each other as soon as the impression cylinder moves down into printing position, and on the other hare arranged to be at or "about dead center when the impression cylinder mm the final hand, the bearerswill be in contact at the instant the cylinder begins its lifting movement. It is common in rotary pressesto arrange the cylinders for very closeortight contact during the printing operation. That is to say, it is customary to have thesewcyl- 1 'inders approach from ten to fifteen onethousandths of an inch closer together than what is commonly calledkiss contact, inorder to obtain good impression. The impression cylinder is moved into and out of impression position by suitable cams and levers which printingposition. If the bearers'of the cylinders are in contact throughout the'whole revolution of the cvlinders, as in former ractice, then when the cylinder lifting'device begins to move the impression cylinder into s :ennss MANUFACTURINGICOMPANY, A CORPORATION or con- 1928. Serial no. 280,068. a

printing position thebearers of the twocyle- 1nders may come into contact before the cylinder moving mechanism has reached its extreme position, and this causes the cylinder lifting device to be seriously strained. As a result, theaction of the cylinder raising and lowering device is not exactly the same on eachsucceedlng impression, which w1ll naturally affectthe registry of the press. Also when thecylinderis-bcing lifted the bearers are in tight contact and in some cases the rotation of the cylinderhas a tendency to draw the cylinders toward each other, and this works against the lifting mechanism, so that the latter is again strained in this operation also. The object of thepresentinvention is to relieve the pressure of the bear ers while the impression cylinder is being moved into printing position, and in the full embodiment of my invention torelievethe pressure at the time the lifting mechanism r commences to lift theimpression cylinder out ofthe printing position. In carrying out the nvention in the simplest form, the bearers of at least one of the cylinders of a couplet is I mutilated; This maybe accomplished bycut ting away a portion ofthe bearers of either the plate or impression cylinderporboth.

In the drawingsforming'part of this application, L

coupletsofa rotarypress, consisting of an impression'and form cylinder, in which View the impression cylinder is shown liftedor out of printing printedsheet,

Figure 2 is asimilar viewzwith additional parts, and showing the-impression cylinder its lower orprintingposition, and V Figure 3 is a plan view thereof. I

be applied to any rotary printing press whether it be'of the single or multi-color type,

position, for delivery of the.

It will be understood that myinventionmay 3 whether it beof the single or two-revolution type, and whatever type of cylinder-lifting.

mechanism is used, but in the present case it is only necessary to illustrate the invention as applied .to'one couplet of a two-revolution press, since its applicationto other couplets will be a 'mere duplication. In the. drawing c Q a l in V i i i i i i 1: Figure '1 1s a sectional-.vlew of one of the I have shown in Figure 1 one of the couplets of a rotary printing press in which 1 is the impression cylinder and 9 is the form or plate cylinder, which carries the printing plate or form. The cylinder 1 is mounted, in accordance with common practice, upon the cylinder shaft 3, which is provided with eccentric boxes 1 which carry the cylinder shaft, and these eccentrics are adapted to raise and lower the impression cylinder with its shaft a slight extent, in order to separate the impression and form cylinders during the delivery revolution of the press and to move the cylinders into close or printing contact during the printing stroke. In a single revolution press the separation only occurs when the cylinder is tripped. The mechanism for operating the eccentrics may be any those well known in the art, and a detailed description of such mechanism is unnecessary to an understanding of the present invention. It is sufficient to indicatethat the lever arm 15, projecting from the eccentric is usually operated upon by suitable levers and links to place the impression and form cylinders in the two positions indicated by Figures 1 and 2.

' In Figure 2 I have indicated at 2' the feed table from which the sheets are fed to the impression cylinder 1 and at 5 there is shown one of the stripper fingers which remove the sheets from the cylinder and direct them upon the delivery device, one end of which is shown at 6. As stated above, there are several ways of arriving at the results under the present inventi on, but in the drawing I have shown by way of example, a bearer 8 on the form cylinder 9, of standard size, or, in other words, this bearer extends completelyaround the form cylinder as in present practice. The bearer 7, however, on the impression cylinder 1, extends but partway around this cylinder, or, in other words, the bearer is mutilated so that the portion 12 is of smaller diameter than the portion 7 The actual impression portion of the cylinder 1 is shown at 10 and this is the portion which carries the sheet to be printed into contact with the type or form on the cylinder 9. At 11 I have indicatedone of the grippers which co-operate withthe impression surface of'the member 10, to grip the leading edge of the sheet for the purpose of carrying the sheet around with theiimpression cylinder. Ijhave shown the bearer 7 of this impression cylinder extending through a greater number of degrees than the impression member '10. 7

In the drawings the impression cylinder 1 will revolve in a counterclockwise direction,

and as stated above, the impression cylinder is shown down or in printing position in Figure 2, whereas it is shown in its raised or separated position in Figure 1. The impression cylinder in Figure 2 has been moved toward the form. cylinder 9 by the usual raising and lowering device acting througlrthe eccentrics 4; and when this movement into printing position has been completed, as shown in Figure 2, the eccentrics are on the dead center line passing between the axes of the impression and form cylinders, or about on the dead center line, where these parts are able to withstand great pressure without distortion. The position of the higher portion 'i of the bearer of the impression cylinder is such that it does not come into contact w" "h the bearer 8 of the form cylinder 5) until iust after the cylinder 1 has been lowered to printing position, as shown in Figure 2. While. the cylinder 1is being lowered, the lower or mutilated portion 12 is opposite the bearer 8, and these surfaces do not come into contact and therefore there is no appreciable resistance to the operation of the lowering device; and the latter is therefore not put under distortion stresses while the lowering operation is taking place. Just after the iniipression cylinder is lowered to the position shown in Figure 2, the bearer 7 comes into contact with the bearer 8 just before the impression surface 10 commences to press the sheet into rolling contact with the form or plate on the cylinder 9. The bearer 7 continues in contact with the bearer 8 until the impression portion 10 of the cylinder 1 has passed the cylinder 9, or until the sheet has been completely printed. Then the bearer portion 7 rides off the bearer 8 as the mutilated portion 12 comes opposite the latter and it is while this portion 12 is opposite the bearer 8 that the cylinder lifting device raises the cylinder 1 into the position shown in Figure 1. It is, therefore, apparent that the pressure between the bearers 7 and 8 is released before the eccentric 1 begins to lift the cylinder .1, so that the strain of this pressure is relieved before the cylinder 1 starts to lift.

Having described my invention, what I claim is 1. In a press the combination of a printing couplet comprising co-operating revolvable cylinders, means for automatically raising and lowering one of said cylinders in relation to the other during the normal operation. of the press, to place said cylinders into and out of printing relation periodically, one of said cylinders having an impression surface extending partially around the same and co-operating bearers on said cylinders, the bearers of at least one of said cylinders being mutilated and the higher portion of said mutilated bearers being approximately coextensive with said impression portion of one of said cylinders.

2. In a press the combination of a printing coupletcomprising co-operating revolvable cylinders, means for automatically raising and lowering one of said cylinders in relation tothe other during the normal 'opera tion of the press, to place said cylinders into and out of printing relation periodicall one of said cylinders having an impression surface extending partially around the same, cooperating bearers on said cylinders, the bearers of oneof said cylinders being mutilated and the higher portion of said mutilated bearers extending through an are for agreater degree than the said impression portion of one of said cylinders. v a a 3. In a press the combination of a printi m ing couplet comprising co-operating revolvable cylinders, means for automaticallyrais. ing and lowering one of said cylinders in relation to the other during the normal operation of the press, to place said cylinders into and out of printing relation periodically, said cylinders having co-operating bearers adapt edto contact with each other to limit the approach of said cylinders in relation to each other, the bearers of one of said cylinders being mutilated whereby the higher portion thereof extends only partially around said cylinder, said raising and lowering ineans being adaptedto operate while the lower portions of said mutilated bearers are opposed to the bearers of the opposing cylinder.

Signed at New London, county of New London, and State ofOonnecticut the 2nd day of April, 1928.

HOWARD LQHETHERINGTON.

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