US2195545A - Sheet-fed printing press - Google Patents

Description

April "2, 1940. s oBB SHEET FED PRINTING mass 3 Sheets-Sheet 1 Filed Nov. 16,- 1957 w a nu,

T l w W April z, 1940. STOBB 2,195,545

SHEET FED PRINTING PRESS Filed Nov. 16, 1937 S Sheets Sheet 2 Z J5- w INVENTOR April 2, 1940. 51-035 2,195,545

' SHEET FED PRINTING PRESS Filed NOV. 16, 1937 3 Sheets-Sheet 3 INVENTOR 472v 570529 ATTORNE Patented Apr. 2, 1940 UNITED STATES "PATENT, OFFICE SHEET-FED PRINTING PRESS Anton Stobb, Elizabeth, N. J. 1 Application November 18, 1932, Serial No. 174,738 3 presses, and aims to provide a press of this char-' acter which is more compact and convenient than those hitherto made.

In ordinary sheet-fed presses, the sheets are carried both to and from the impression cylinder by means of conveyors. This requires placing the piles of sheets to be printed and printed sheets on opposite sides of the machine-an arrangement which requires a large amount of floor space and renders access to the machine diflicult.

A feature of the present invention lies in the provision of a sheet-fed printing press in which a continuously rotating impression cylinder takes the sheets to be printed directly from a pile adjacent the impression cylinder. Preferably, the'pile of unprinted sheets is located within the frame of the press, and the printed sheets 20 are delivered to a shelf at the rear of the press. In this manner, the shelves supporting the fresh and the printed sheets are arranged so that they are close together and operated by a single operating mechanism, and so that the press-man 25 can readily inspect the press from the front.

More specifically, my printing press includes an impression cylinder provided with gripping means which moves with respect to the cylinder so that it is adapted to pick up the top sheet from 80 a stationary pile of sheets.

Other features, objects and advantages of my invention will become apparent from the following detailed description of one form of press in accordance with the invention, reference being 85 had to the accompanying drawings, wherein:

Fig. 1 is a side elevation of one form of printing press in accordance with the invention;

Fig. 2 is a section, through the impression cylinder of the press on 40 the line 2-2 of Fig. '1;

Fig. 3 is a horizontal'section, also on enlarged scale, taken above the pile of sheets shown in Fig. 1;

Fig. 4 is a vertical section taken on the line 45 4-4 of F18. 3;

Fig. 5 is a vertical section taken on 8-8 of Fig. 2, looking toward'the left; Figs. 6 and '7 are views similar to Fig. 5, but showing the partsin successive operating posi- 50 tions; i v

Fig. 8 is a section taken on the line 8-4 of Fig. 2, looking in the direction of the arrows;

and

the line Figs. 9 and 10 are broken away sections taken 55 on the lines 8-8 and lI-ll of Fig. 5.

on enlarged scale, taken The printing press shown for the purpose oi illustrating my invention is a lithographic, offset press. The pressincludes side frames II which support, a plate cylinder l2, a blanket cylinder l3 and an impression cylinder l4. Sup- 5 ported on the top of the side-frames II is a sub-frame l5 in which are mounted the usual means It and I1 for supplying moisture and ink, respectively, to the plate cylinder l2. This subframe is advantageously adapted to slide in suitable grooves IS in the side-frames ll, so that the inking mechanism can be moved out of contact with the plate cylinder, while the moistening mechanism remains in contact with this cylinder.

The pile of sheets to be printed, indicated at 20, is supported within the frame of the press, between side-frames II, with the forward edges of the sheets below the axis of the impression cylinder M. The impression cylinder has end walls Ila and Nb and is mounted through stub shafts 2|, 22 on the side frames H. The stub shaft 22 is driven at constant speed through a gear 23 from'any suitable source of power. As best shown in Figs. 5 to 8, the impression cylinder is provided with .an open sector 24 within which are mounted means for. gripping the top sheet of the pile, this sheet being wrapped around the solidwail IQ of the impression cylinder and carried into contact with the blanket cylinder i3, which prints the impressions on the sheets. The gripper means illustrated comprises a plate 25 mounted in the open sector 24 of the impression cylinder and adapted to swing circumferentially rearwardly with respect to the cylinder during a part of each rotation of the cylinder, so that it can pick up the top sheet from the pile 20 while the impression cylinder is rotating at constant speed.

This may be accomplished by mounting the plate 25 on studs 26, 21 which are carried by the end walls of the cylinder eccentric to the axis of the rotation of the cylinder. Secured to the inner end of the plate 25 is a gear segment 28 which meshes with a gear segment 29 secured to one arm of a bell-crank 30 mounted through a bearing 32 in end wall Ila of the impression cylinder. On the outer arm of the bell-crank there is mounted a cam follower 33 which runs over a stationary cam 34, secured to side-frame II. The plate 25 is of such length that its outer end is, adapted to contact the top sheet of the pile when the parts occupy the positions shown in Fig. 6, and it is preferably as wide as the widest sheet to be printed on the press. The positions of the studs 20, 21 and the length of the plate 25 are such that the plate can be swung mwanefepen sector in thecylinder, and such that the outer end of the gripping plate will project slightly beyond the circumference of the cyl- 34a, from its position in Fig. to its position in Fig. 6. This down movement brings the edge of the gripper into contact with the. top sheet on the pile 20, whereupon suction is applied as hereafter described. The continued swinging of the plate 25, to its position shown in Fig. 7, lifts the edge of the sheet and carries-it forward.

As best shown in Fig. 2, the gripper plate is provided with generally radial passages 35 which communicate with a passage 35 extending widthwise of theplate. Passage 35 is closed at one end by stud 25, and communicates at the other end, through hollow stud 21, with suction pipe 31 by means of a passage 38 in gear 39. The pipe 31 is connected to any suitable source of vacuum, and the gear 39 is rotated in synchronism with impression cylinder so that the passage 38 connects the passages 35 and 31 when the gripper plate contacts the sheets on pile 20, and until the sheets pass the blanket cylinder l3 and reach the delivery mechanism hereafter described, whereupon the vacuum is disconnected from passage 35. Suitable valves 40 are provided in the passages 35 so that some of these passages can be closed when relatively narrow sheets are to be printed.

Mechanical grippers are preferably provided to assist the pneumatic gripper means. These consist of fingers d! secured to rock shaft 52, which is journalled in arms ifisecurecl to the plate 25. In order to swing the fingers 4! into engagement with the paper, there is secured to one end of the rock shaft 42 a gear segment 44 which is adapted to mesh with a gear segment 45 (as best shown in Fig. 8), the gear segment #5 being secured to end wall Nb of the impression cylinder by means of bolts 45. Since the gear segment rotates with the impression cylinder, and since the gear segment 44 is carried by the plate 25, the rearward motion of the plate 25 with respect to the impression cylinder will cause the fingers 4| to swing into engagement with the paper, as indicated in Fig. 7. After a sheet has been carried between the impression cylinder and the blanket cylinder, the cam follower 53 will run onto the flat portion of the stationary cam 34, and this will cause the plate 25 to swing into the positionit occupies in Fig. 5. At the same time, the fingers ll will be swung into the open sector of the impression cylinder, thus releasing the paper.

I I. The position of the slides, and consequently of the stops, may be adjusted by thumbscrews 53 which are threaded into the slides and through brackets 54 secured to the side-frames. At the rear end of the pile there is provided a stop 55 5 which extends along the rear face of the pile, and is held against the paper by means of a bellcrank 51 pivoted on vertical shaft 49. If desired, a similar bell-crank (not shown) may be provided at the bottom of the pile. The position of the stop 55 may be adjusted in any suitable manner, for instance, by means of a handwheel 58 on a shaft 59 which is,provided with a ed to reciprocate between guides 55 fastened to the side-frames. The roller 55 is constantly driven through a sprocket 55. A pair of cam followers 10 are mounted on stub shafts 59 secured to the upper ends of the slides 51, for engagement by cams I I which are mounted through elongated openings 53 for rotation by shaft 12. This shaft is driven at constant speed from a gear 13, which is rotated at the same sp'eedas the impression cylinder. The shape of the cams 1| is such that the roller 55 is dropped onto the top of pile 20 prior to the time the gripper plate 25 reaches its position shown in Fig. 5. The rotation of the diagonal roller 55, in contact with the top sheet of the pile, registers this sheet by urging it against stops, hereafter described, at the end and side of. the pile. The roller also buckles the top sheet to form an air space between this sheet and the next sheet. Just after suction is applied to the top sheet by the gripper means, the cams ll move from their positions shown in Fig. 6 to their positions shown in Fig. '7, thus lifting the roller 55 off the paper, and permitting the gripper means to withdraw the top sheet from the pile. After the top sheet has been withdrawn, the continued rotation of the cams 10 returns. the 'roller 55 to its position in Fig. 5. In order to assist the separation of the top sheet, a blast of air is constantly blown against the rear face of the top of the'pile through a slot 14, the air being supplied through suitable pipe 15.

Secured to the lower ends of the slides 51 is a hold-down plate 15 which extends forwardly, terminating in spaced feet I1 which bear against the top of the .pile of paper, thus keeping the forward end of the top sheet flat while the roller 55 buckles it. The feet 11 and the ends of the tubes 35 of the gripper plate are so spaced and proportioned that the tubes 35 can engage the paper between the feet I1. As best shown in Figs. 00 3 and 10, the plate I5 is provided with a series of holes 18 which are threaded to receive bolts IQ for attaching angle irons 80 at the sides of the pile of paper in order to align the side edges of In order to take the sheets from the impression cylinder, after they have been printed, there is provided a chain conveyor, of usual construction, having gripper fingers 82, also'of usual construction. The conveyor 8|, which is driven by a sprocket 8la, delivers the sheets to pile 83.

The operation of the press will be apparent from the foregoing description, but it may be briefly summarized. While the gripper on the impression. cylinder is moving toward its position I5 shown in Fig. 6, in which it engagesthe top sheet of the pile, the roller which buckles the top sheet cam, the gripper moves to its position shown in Fig. 7, thus lifting the forward edge of the top sheet from the pile,

During the succeeding half-revolution of the impression cylinder, which begins when the rear edge of the open sector passes the pile of sheets as shown in Fig. 6, the cam follower moves on an arcuate portion of the cam, so that the gripper maintains the same position with respect to the cylinder as is shown in Fig. 6, that is to say, it stays at the rear edge of the open sector. During this half-revolution suction is maintained in the gripper, and; the sheet is wrapped around the solid portion of the cylindrical wall by the rotation of the cylinder. It is printed as it passes on the impression cylinder under the blanket cylinder.

Whenthe front edge of the sheet reaches the delivery conveyor, it is seized by the grippers on this conveyor. The grippers on the impression cylinder are released, and gripper plate is swung ahead from the rear edge of the open sector toward the front edge of the open sector, in time to permit the sheet to betaken from the impression cylinder. The parts are then returnedto their positions shown in Fig. 5.

A further feature of my press, which is made practical by the close spacing of the feeding and delivery piles, consists in providing a common operating mechanism for the feed pile shelf and the delivery pile shelf 84 which simultaneously raises the feed shelf and lowers the delivery shelf at the same rate. The shelves are mounted,

for vertical movement by means of rollers 9| in vertical grooves in the side-frames. The grooves in each side-frame are only a short distance apart, and between them is a sprocket chain running over-sprockets 81 which are driven at the rate at which it is desired to elevate the feed shelf and to depress the delivery shelf. The upwardly moving reach of the chain engages a sprocket 89 on the feed shelf, while the downwardly moving reach of the chain engages a sprocket 90 on the delivery shelf, so that the weights of the'two shelves are counterbalanced. In order to adjust the level of one shelf independently of the other, each is provided with-a vertical shaft 92, to which is keyed aworm 93. These worms are in mesh with sprockets 89 and 90. To the upper ends ofthe shafts 92 there are attached bevel gears 94 which mesh with gears connected to handwheels 95. By turning either one of the handwheels in the proper direction, either shelf may be raised or lowered, as desired.

The terms and expressions which have been employed are used as terms of description and not of limitation, and'there is no intention, in the use of such terms and expressions, of excluding any equivalents of the features shown and described, or portions thereof, but it is recognized that various modifications are possible within thescope'of the invention claimed.

What I claim is:

.1., In asheet-fed printing press having an impression cylinder, means to support a pile of sheets directly beneath said cylinder, means to admit air between the top sheet of said pile and the other sheets, a device for buckling a portion of said top sheet, and means carried by said c linder and constructed and arran ed in withdraw the top-sheet from said pile on. each revolution of said cylinder. 2. ,In a printing press having .a rotary impression cylinder, an open sector in the cylinder, pneumatic gripper means mounted in said sec tor for movement relative to the rotation of the.

cylinder, and mechanical gripper means operable by said first-named gripper means.

3. In a printing press having a rotary impression cylinder, an open sector in the cylinder,

pneumatic gripper means mounted in said sec tor'for movement relative to the rotation of the cylinder, gripperfingers carried by said gripper means, and means to actuate said fingers upon movement of said gripper means relative to" the cylinder.

4. In -a printing press, a rotary impression cylinder having an open sector, a suction plate pivotedfor'swinging in said sector about an axis positioned so that the end of the plate protrudes outside the circumference of the cylinder during a portion of :the swinging movement, gripper fingers carried by said suction plate, means to swing said plate rearwardly with respect to the direction of rotation of the cylinder, and means operated by the relative movement of the plate and cylinder for actuating the gripper fingers. 4

5. In a sheet-fed printing press, means to support a stationary pile of sheets, an impression cylinder, means mounted onsaid impression cylinder and comprising pneumaticand mechanical grippers constructed and arranged to withdraw 6. In a sheet-fed printing press, means to support a stationary pile of sheets, an impression cylinder, means to raise a portion of the top sheet of said pile to admit air. beneath it, means comprising pneumatic and mechanical grippers mounted on said impression cylinder and constructed and arranged to withdraw the top sheet directly from said pile, and means to swing said last-named means rearwardly with respect to the rotation of the impression cylinder during a portion of each revolution.

7. In a printing press, a shelf for supporting a pile of sheets, stops adjacent the top of the pile at one end and one side of the sheets, and combing means constructed and arranged to urge the top sheet of the pile into contact with said stops. r

8. In a printing press, a shelf for supporting a pile of sheets, stops adjacent the top of the pile at one end and one side of the sheets, a continuously rotating diagonal roller adapted to contact the top sheet of the pile and register it withsaid stops, and means to intermittently contact said roller with the top sheet of the pile.

9. In a printing press, a shelf for supporting a pile of sheets, means for registering the top sheet on the pile, an impression cylinder mounted adjacent one edge of said top sheet, and sheetwithdrawing means mounted on said impression cylinder and constructed and arranged to engage the top sheet while substantially stationary and thereupon withdraw the top sheet from said pile.

10. A sheet-fed printing press comprising means to support a pile of sheets, printing mechanism including an impression cylinder-supported side of the press, whereby said printing mecha- 7| nism is open for inspection at the first-named side of the press.

11. A sheet-fed printing press comprising means to support a pile of sheets, printing'mechanism including an impression cylinder supported adjacent one edge of the top sheet of said pile, said printing mechanism being adjacent one side of the press, inking mechanism mounted on the top of the press, and delivery means at the opposite side of the press, whereby said printing mechanism is open for inspection at the first-named side of the press.

12'. A sheet-fed printing press comprising a feed and a delivery pile, impression and plate cylinders located above and extending over the feeder end of said feed pile, means attached to the cylinder for withdrawing a top sheet directly from said feed pile, and inking devices arranged on top and around the plate cylinder and extending toward the delivery end of the press.

13. A sheet-fed printing press comprising an impression cylinder, means to support a pile of sheets, means to align the edges of sheets in the pile, means mounted on the impression cylinder and constructed and arranged to withdraw the top sheet from its aligned position in the pile and hold said sheet in register on the impression cylinder, and means to swing said last-named means rearwardly with respect to the rotation of the impression cylinder whereby said last-named means is practically stationary as it engages the top sheet of the pile during each revolution 01' the impression cylinder.

14. In a printing press, a shelf for supportin a pile of sheets, means to register the top sheet on the pile, an impression cylinder mounted ad Jacent one edge of said top sheet, sheet-withdrawing means mounted on said impression cylinder for swinging rearwardly with respect to the rotation of said cylinder, and means constructed and arranged to swing said sheet-withdrawing means rearwardly at a speed such thatthe sheetwithdrawing means is substantially stationary as it engages the top sheet of the pile,'and to thereafter draw the sheet forward at increasing speed as the impression cylinder continues to rotate.

15. In a printing press, a shelf for supporting a pile of sheets, means to register the top sheet on the pile, an impression cylinder mounted adjacent one edge of said top sheet, suction means mounted on said impression cylinder for engaging the top sheet of the pile, means constructed and arranged to swing said suction means rearwardly at a speed such that said suction means .is substantially stationary as it engages the top sheet of the pile. and to thereafter draw the sheet forward, and mechanical grippers for holding the sheet in register on the impression cylinder.

16. In a sheet-fed printing press, the combination of an impression cylinder, means for supporting a pile of sheets with one edge beneath the impression cylinder, and means mounted on the impression cylinder for withdrawing sheets from the top of said pile, said means comprising a suction arm adapted to swing rearwardly with respect to the impression cylinder, and a mechanical gripper carried by said arm and adapted to hold the sheet in register on the impression cylinder.

ANTON STOBB.

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