US2515355A

US2515355A - Perfecting offset press

Info

Publication number: US2515355A
Application number: US604955A
Authority: US
Inventors: Howard A Pritchard
Original assignee: Harris Seybold Co
Current assignee: Harris Corp
Priority date: 1945-07-13
Filing date: 1945-07-13
Publication date: 1950-07-18
Anticipated expiration: 1967-07-18

Description

July 18, 1950 H. A. PRITCHARD momma oFFsE'r mass 2 Sheets-She 1 Filed July 13, 1945 IIYVVENTOR. l/awneo A PE/TCHABD 2% 1W B M 7m HT ORNEYJ July 18, 1950 H. A. PRITCHARD PERFECTING OFFSET PRESS 2 Sheets-Sheet 2 Filed July 13, 1945 INVENTOR. 190M420 A PE/TCHAQD BY 7km W15 HTTOR/VE Y5 Patented July 18, 1950 rsarncrmo OFFSET-PRESS Howard A. Prltchard, Hiram, Ohio, assignor to Harrls-Seybold Company, Cleveland, Ohio, a

corporation oi Delaware Application July 13, 1945, Serial No. 604,955

4 Claims.

This invention relates to improvements in perfecting ofiset presses and has to do primarily with the arrangement of the plate and blanket cylinders of the two printing units symmetrically, and such disposition of other parts that relatively large areas of those cylinders are exposed on the outer sides of the units for most convenient access by the operators, the invention providing also that each pair of plate and blanket cylinders shall turn in the same direction relative to the adjacent working space for the convenience of the men working on the press.

One of the objects of the invention is the provision of a press in which the cylinders of the two units are so disposed and so interconnected by the driving means that two operators may be engaged simultaneously in performing identical work upon the two units, thereby facilitating and expediting the preparation of the machine for printing.

Another object is the provision of a perfecting press of the character stated wherein the inkers may be disposed above the plate cylinders, in other words in their most advantageous positions, and yet leave the plate cylinder and blanket cylinder adequately accessible.

Other objects and features of novelty will appear as I proceed with the description of those embodiments of the invention which, for the purposes of the present application, I have illustrated in the accompanying drawings, in which Fig. 1 is a diagrammatic view partially in side elevation and partially in vertical section of an ofiset perfecting printing press embodying my sent the plate, blanket and impression cylinders V which is symmetrical with that of the latter cylinders. Consequently, the base or longest leg of the triangle, the points of which are cut by the axes of the cylinders l3, l4 and I5, faces in the direction of the similar leg of the triangle first mentioned.

In order to space the two printing units apart far enough to provide sufilcient room between them and to reverse the sheets for printing on the opposite sides, I employ two transfer cylinders i6 and IT. The cylinders i2, i5, I6 and II are all provided with conventional sheet grippers and gripper operating means of known character in order that the sheets printed on one side may be accurately transferred and the second printing caused to occupy a position on the sheet corresponding to that of the first printing.

The means which I employ for feeding sheets to the press is so constituted as to deliver sheets to the grippers of cylinder l2 at a point below the axis of that cylinder and on the side thereof which is nearest the blanket cylinder ii. For this purpose I have shown herein diagrammatically a feed table i8 over which sheets are carried by tapes l9 from a pile 20. After the usual front and side registration by means not shown,

the sheets are taken by the grippers on a feed.

cylinder 2i and transferred therefrom to the grippers of a second feed cylinder 22 which delivers them to the grippers of impression cylinder 82.

An operators platform 23 may be disposed above the feed table in convenient relation to the cylinders i0 and ii, and if desired may be hinged at one end upon a cross rod 2 in order that when it is not in use it may be swung up out of the way to expose to view and render accessible the feed table and the sheets moving thereover After the sheets have received an imprint from the second unit they are taken by grippers on a transfer cylinder 25 and transferred to travelin grippers 26 on a chain delivery 21 which carries the sheets upwardly and then over the top of the second unit and down to a delivery pile 28.

The inkers for the first and second units of the press are indicated generally by the reference numerals 30 and 3!. They are disposed above the respective plate cylinders i0 and i3, but substantially upon the inner sides of planes through the axes of cylinders I 0 and ii of the one unit and I 3 and M of the other, these planes being indicated in the drawings by the lines 32 and 33 respectively. This disposition of the inkers enables them to partake of the well-known advantages of inkers arranged over the plate cylinders, while at the same time permitting the dampening mechanisms 34 and 35 to be disposed well above the axes of the plate cylinders. Hence the outer surfaces of the two pairs of cylinders III, II and l3, H are almost fullyexposed and therefore easily reached and worked upon by the operators. Furthermore, by reason of the disposition of the various cylinders and the armay be identical with the corresponding parts of the Fig. 1 construction, although the spacing of the two pairs of plate and blanket cylinders may be somewhat different. In this form however there are no separate transfer cylinders between I the two units.' The units have impression cylinders 36 and 31 respectively of double size compared with the plate and blanket cylinders. Each of these cylinders has two sheet supporting sur- The mode of operation and the advantages of this second form of the invention are substantially the same as in the case of the first described form.

Having thus described my invention, I claim:

1. In a sheet fed perfecting offset press; two printing units each comprising plate and blanket cylinders of the same size in verticalalignment and an impression cylinder of double size, the impression cylinder of each unit being disposed below the axis of the blanket cylinder on the side thereof toward the other unit, the impression cylinders of both units having two sets of sheet grippers, the impression cylinders and their grippers being so disposed that the grippers of the first unit impression cylinder transfer sheets didirectly to the grippers of the second unit impression cylinder.

2. In a sheet fed perfecting offset press, first and second printing units each comprising plate,

. blanket and impression cylinders, each unit being faces and two sets of grippers, the grippers of der may be transferred directly to the grippers ll 9f cylinder 31, and a sheet taken by the grippers 38 may be correspondingly transferred directly to the grippers 40. Therefore the impression cylinders, in addition to performing their usual functions, in this case function also as transfer cylinders. As compared with the first form of the invention therefore, two cylinders with their bearings and driving connections are eliminated and the machine is simplified to that extent.

In this case the axes of the three cylinders of each unit cut the points of a triangle, but the triangle in this case is not an isosceles triangle. However, as in the case of Fig. 1, the longest legs of the two triangles face toward each other.

Feed cylinders 2| and 22 similar to the cylinders 2| and 22 of Fig. 1 may be employed for transferring sheets from a feed board l8 to the impression cylinder 36. The sheets after being imprinted on both sides by the two units of the machine are taken by grippers on a transfer cylinder 25' and transferred to grippers 26 on gripper bars forming parts of a chain delivery 21', all of these parts being similar to the parts 25, 26 and 21 of Fig. 1.

arranged with the plate cylinder above the blanket cylinder and the impression cylinder on the side of the blanket cylinder toward the other unit,

a sheet feed table arranged on the side of the first unit remote from the second printing unit, gripper means for conveying sheets received from the table under the first unit blanket cylinder to the first unit impression cylinder, partly around each impression cylinder, upwardly between the plate cylinders and toward a delivery point, said gripper means placing the sheets upon the first impression cylinder at a point below its axis and removing the sheets from the second impression cylinder at a point above the axis of the latter cylinder.

3. Mechanism as claimed in claim 2 wherein said sheet gripper means includes a'rotary gripper-equipped sheet handling cylinder between the feed table and the first impression cylinder for placing the sheets upon the latter.

4. Mechanism as claimed in claim 2 wherein said sheet gripper means includes two sets of moving sheet grippers between the feed table and the first impression cylinder, one of which is adapted to place the sheets upon the first impression cylinder. I

HOWARD A. PRITCI-IARD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Harris Oct. 1'7, 1944