US2578700A - Sheet controlled interrupter for offset printing presses - Google Patents

Description

1951 c. w. HARRO .D ET AL 2,578,700

SHEET CONTROLLED INTERRUPTER FOR OFFSET PRINTING PRESSES Filed July 12, 1946 6 Sheets-Sheet 1 INVENTOR: CAMP/.55 VIZ/702201.12 BY flew/w? 5. Waooew-w Dec. 18, 1951 c. w. HARROLD ET AL SHEET CONTROLLED INTERRUPTER FOR OFFSET PRINTING PRESSES 6 Sheets-Sheet 2 Filed July 12, 1946 F1610 INVENTORS CHARLES W l/nnemo By 1 27710? 5. Wow/PUFF T'TOIQNEYS Dec. 18, 1951 c. w. HARROLD ET AL 2,578,700

SHEET CONTROLLED INTERRUPTER FOR OFFSET PRINTING PRESSES 6 Sheets-Sheet 5 Filed July 12, 1946 T. 0 R w Wm nW r I n r W5 A 1951 c. w. HARROLD ET AL 2,578,700

SHEET CONTROLLED INTERRUPTER FOR OFFSET PRINTING PRESSES Filed July 12, 1946 6 Sheets-Sheet 4 IN VEN TORS O/muss w/mmeobo ien/0e 5. WOOORUFF 2 2 W Z W, I i HfTOE/VE Y5 Dec. 18, 1951 c. w. HARROLD ETAL SHEET CONTROLLED INTERRUPTER FOR OFFSET PRINTING PRESSES Filed July 12, 1946 6 Sheets-Sheet 5 INVENTORS C/IABL'ES Wl/nezou: y flan/0e 5. WOODEUFF Dec. 18, 1951 c. w. HARROLD ET AL SHEET CONTROLLED INTERRUPTER FOR OFFSET PRINTING PRESSES Filed July 12, 1946 6 Sheets-Sheet 6 INVENTOR5 611142455 Wf/Aw y flew/0e 5. M/ooaeuFF Patented Dec. 18, 1951 SHEET CONTROLLED INTERRUPTEB FOR OFFSET PRINTING PRESSES Charles W. Han-old, University Heights, and

Arthur B. Woodrufl, Brecksville, Ohio, assignors to Harris-Seyboid Company, Cleveland, Ohio, a corporation of Delaware Application July 12, 1946, Serial No. 683,130

16 Claims.

This invention relates to improvements in printing presses, and has to do particularly with impression throwofi mechanism for-rotary ofl'set presses, especially mechanism for throwing the blanket cylinder off from the plate cylinder and from the impression cylinder in two sequential steps, and to means responsive to failure of sheet feed for setting such mechanism into operation.

One of the objects of the invention is the provision of means dependent upon the presence or absence of a sheet in the printing unit itself for controlling the throwoff for that unit, so that if action of the feeder serving the press is interrupted the desired throwofi of the press unit takes place at the desired time regardless of the extent of sheet transfer means employed between the sheet feeder and the impression cylinder.

Another object is the provision of improved inner and outer eccentric mountings for the blanket cylinder.

Another object is the provision of improved means for adjusting the impression pressure or compensating for different stock thicknesses as a part of the throwofi mechanism.

A further object is the provision of throwofl means comprising two toggle mechanisms in series for enabling the throwoii to function properly in spite of adjustments of the anchor pivot of the toggle mechanism directly connected with the eccentric mounting of a cylinder.

Still another object is the provision of sheet detector means acting to latch the throwofl mechanism in printing position except when a sheet fails to be presented properly to the sheet grippers, and serving electrically in such case to withdraw the latch at a given point in the cycle of the unit.

Another object is the provision of means for disabling partially or completely the throwofi mechanism when desired.

Other objects and features of novelty will appear as we proceed with the description of that embodiment of the invention which, for the purposes of the present application, we have illustrated in the accompanying drawings, in which Fig. 1 is a diagrammatic side elevational view of one printing unit of a rotary offset press embodying the invention, and showing the impression on.

Fig. 2 is a continuation of Fig. 1 showing a portion of a sheet feeder, and sheet transfer mechanism interposed between the feeder and the first unit of the press.

Fig. 3 is a view similar to Fig. 1 but showing both parts of the throwofi mechanism operated to provide a narrow gap between the blanket cylinder and each of the other cylinders of the unit.

Fig. 4 is a view similar to Fig. 3 but with the second part of the throwofl mechanism disabled, operating contact between the plate and blanket cylinders being accordingly maintained.

Fig. 5 is a. detail sectional view on a larger scale showing a sheet gripper and accompanying sheet feeler with electrical contacts controlled thereby, the view being taken substantially on the line 5-5 of Fig. 6.

Fig. 6 is a fragmental view at right' angles to Fig. 5.

Fig. 7 is a detail view on a larger scale of the eccentric means for adjusting the position of the anchor pivot for the toggle mechanism which operates the throwofl. of the blanket cylinder from the impression cylinder, the view being taken substantially on the line 1-1 of Fig. 8.

Fig. 8 is a plan view, partly in section along the line 8-8 of Fig. '7.

Fig. 9 is a detail elevational view on a larger scale looking in the direction of arrows 9-8 of Fig. 1.

Fig. 10 is a sectional view through one end of the blanket cylinder mounting, the view being taken substantially on the line I0l0 of Fig. l, and

Fig. 11 is an enlarged view oi a portion of a feeder throwoff shown in Fig. 2.

In the drawings I0 is the impression cylinder of a rotary offset printing unit, which also comprises a blanket cylinder H and a plate cylinder l2. A blanket I3 is wrapped around cylinder II and secured within the gap 14 thereof in the usual manner, and the usual plate l5 surrounds cylinder l2 and is clamped within gap it of that cylinder.

Plate cylinder shaft I1 and impression cylinder shaft it are carried in the main frame I! of the press, these shafts being preferably mounted in fixed journals in the frame. The cylinders are rotated in the directions shown continuously during the operation of the press by gearing of conventional character, not shown.

The impression cylinder I0 is equipped with the usual gripper shaft 20 carrying a series of sheet grippers, a particular one of which is'shown at 2|. These grippers may be secured directly to the gripper shaft as by setscrews 22, or they may be loosely mounted upon the gripper shaft and actuated in a well-known manner by dogs keyed to the shaft. In either event they Y are opened and closed at the proper times by any suitable mechanism, not shown.

Sheets may be conveyed to grippers 2| by any "shaft 45.

suitable means. In the illustrated case this means comprise a conveying cylinder 23 provided with grippers 24 which function to release a. sheet as it is taken by grippers 2 I. The sheets are car ried by the latter grippers and by the impression cylinder |9 into contact with blanket cylinder by which they are printed, and thence to the grippers 25 of a delivery cylinder or any other suitable device for conveying sheets to a delivery or to another unit of the press.

The blanket cylinder H is provided with a shaft 26 rigid with the cylinder, each end of the shaft being supported in a bearing carried by an inner eccentric block 28 having a projecting ear 29 connected to mechanism for movement of the block through a small angle, as will be presently described. Block 28 in turn is carried in an antifriction bearing 3| within an outer eccentric block 32. Finally block 32 is mounted within an antifriction bearing 33 carried in the main frame i9. Eccentric block 32 is provided with an ear 34 to which there is connected mechanism, presently to be described, for turning block 32 through a small angle.

Both ends of shaft 26 are mounted as above described, there being a pair of eccentric blocks 28 and a pair of eccentric blocks 32, each mounted in antifriction bearings. In conformity with common practice these blocks will be referred to hereinafter simply as eccentrics.

A limited rotation of the two eccentrics 28 causes movement of the cylinder toward or away from plate cylinder |2 without substantially altering its position in relation to impression cylinder l0, and a limited rotation of the two eccentrics 32 causes movement of the blanket cylinder toward or away from impression cylinder ||l without substantially altering its relation to plate cylinder i2. The center of shaft 28 is indicated at a, the center of eccentric 28 at b, and the center of eccentric 32 at c.

At each side of the press ear 34 of eccentric 32 carries a pin 35 which is connected by a link 36 of adjustable length to a pin 31 of a lever 38 keyed to a shaft 39 which extends across the press, shaft 39 being sometimes referred to hereinafter as an anchor pivot. Shaft 39 is rotatably mounted near each end in a link 40 which is pivotally supported on a stud 4| in frame l9, see particularly Fig. 3. pin 42 which takes into a hole in one end of a further link 43. The other end of the latter link is mounted on an eccentric bearing 44, keyed to a shaft 45, the latter shaft being rotatably journaled in frame i9 and extending across the press.

At one side of the press, just inside the main frame IS, a worm wheel sector 46 is keyed to This sector meshes with a worm 41 keyed or pinned to a short shaft 48 between bearings 49 fixed to the inner surface of frame l9. Shaft 48 is rotatable in bearings 49 and in a hole in a stud 50 fixed in frame l9, and has secured to its upper end a knob which may be turned by hand.

Through the connections just described it is possible, by turning knob 5|, to adjust the angular position of shaft 45 and thereby move the shaft 39 bodily toward or away from the center of shaft 45, the shaft 39 moving at all times parallel to itself in an arc about the studs 4|. This adjustment of shaft 39 enables the operator to limit the extent of movement of blanket cylinder toward impression cylinder l9 when the lever 38 and link 36 are in posi- Each link 40 carries a tion to bring shaft 39, pin 31 and pin 35 substantially into alignment as shown in Fig. l, in other words when the toggle composed of lever 38 and link 36 is on toggle." In practice the position of the blanket cylinder with respect to the impression cylinder for different impression pressures or for different stock thicknesses is indicated by graduations upon a suitable scale carried by the frame, the pointer for such scale being carried by the shaft or the sector 46.

Each of the levers 38 is provided with a second pin 52 which rotatably receives one end of a link 53, the other end of which surrounds a pin 54 in a lever 55 which is carried on a shaft 56 Journalled in frame I9. There are levers 55 on both ends of shaft 56. These levers are rotatable through a limited angle from a position where abutment 51 of each lever engages a stop screw 58 carried by frame H] as shown in Fig. 1 to a position where shaft 56, pin 54 and pin 52 are in substantial alignment, as in Fig. 3. In practice pin 54 is moved slightly past the position of alignment, whereby the parts tend to remain on toggle."

The lever 55 on one side of the press is provided with two outwardly projecting studs, 58, 60, on opposite sides of shaft 56. These studs are adapted to be engaged selectively by a thrust block 6| having shoulders 62, 63 for engaging the studs 59, 68, and an upward projection 64 for limiting the sidewise movement of block 6|. Block 6| is pivotally mounted on pin 65 in bell crank 66' rotatably supported on stud 61 in frame IS. The other arm of hell crank 66 is connected by link 68 to one end of a cam lever 69 pivoted on stud 69 the other end of which lever carries a follower 10 which follows a cam 7| keyed to shaft 12 of delivery cylinder 25. Lever 69 is urged toward cam H by spring 13.

By means of the mechanism described, cam H causes thrust block 6| to be periodically raised and lowered to engage one or the other of the studs 59, depending upon whether block 6| is moved to the left or right on its pivot 65. The means employed to control the position of block will bedescribed hereinafter. If this block engages pin 66, lever 55 is turned counterclockwise to the position shown in Fig. 1, thereby pulling lever 38 down until shaft 39, pin 31 and pin 35 are substantially in line, that is on toggle. This causes rotation of eccentrics 32 and moves blanket cylinder toward impression cylinder in. If block 6| engages pin 59, lever 55 is swung clockwise until shaft 56, pin 54 and pin 52 are substantially in line, that is on toggle as in Fig. 2, and pin 31 is moved off toggle." This causes eccentrics 32 to rotate clockwise and move the blanket cylinder away from the impression cylinder.

The eccentrics 28 are moved by the following means. On each side of the press a pin '14 is mounted in ear 29 and connected by rod 16 to a pin I6 in a lever 11 similar in function and operation to lever 55. Levers H are keyed to a shaft 18 extending across the press and have movement from a position against stop screws I9 such that shaft I8, pin 16 and pin 14 are substantially on toggle as in Fig. 1 to the position shown in Fig.3.

A lever 11 on one side of the press only has two outwardly projecting studs 80, 8| which are adapted to be engaged by the shoulders 82, 83 of a thrust block 84 pivotally carried on stud 85 mounted in a cam lever 86 which is pivoted on a stud 81 in frame I0. Lever 80 at one end has a follower 88 which is pressed against cam 1| by spring 89 acting on the other end of the lever. As cam 1| rotates it rocks lever 88 andraises thrust block 04 into engagement with one or the other of the studs 80, 8|. when it engages stud '80, lever 11 is turned clockwise to the position of Fig. 1 where pin 10 is on toggle" and eccentric 28 has been turned counterclockwise to move the blanket cylinder toward the plate cylinder I2. when block 84 engages stud 8| lever 11 is turned counterclockwise to the position shown in Fig. 3 where pin 10 is "off toggle and the blanket cylinder has been moved away from the plate cylinder I2.

The two levers 11 and 55 are interconnected by the following means. Lever 11 carries a stud 90 which is connected by rod 9| to a noddle pin 92 inlever 93, see Fig. 4, which is loosely mounted on a pivot stud 94 in frame I0. On this same stud 94 there is also pivotally mounted a bell crank lever 95, the lower arm of which carries a noddle pin 96 in which slides a rod 81 having a head surrounding stud 98 fixed in thrust block Surrounding rod 91 there are two compression springs 99, I00, on opposite sides of noddle pin 00 abutting against collars IOI and I02.

Lever 93 and bell crank 95 are arranged so that movement of the former is transmitted to the latter or is not so transmitted, according to the desire of the press operator. Lever 93 is provided with a hole I03, Fig. 4, and bell crank 95 is provided with a slidable pin I04 which may be inserted into hole I08 when it is desired to lock the two levers together for movement in unisun, which pin may be retracted from engagement with hole I03 when it is desired not to transmit movement of lever 93 to bell crank 95.

By the connections just described it will be seen that when pin I04 is in position in hole I03 a movement of lever 11 to the right to the position shown in Fig. 1 will cause thrust block 6| to be resiliently pulled over against stud 60 of lever 55, and movement of lever 11 to the left to the position shown in Fig. 3 will cause block 6| to be resiliently pushed over against stud 59. If pin I04 is withdrawn from hole I03 as in Fig. 4, movement of lever 11 in either direction will have no effect on block 6|, but due to the action of gravity upon bell crank 95 projection 64 on block 6| will tend to rest against stud 59.

Thrust block 84 is swung to the right or left about its pivot in accordance with the presence or absence of a sheet on impression cylinder I0 by the following mechanism. A control rod 105 extends from a stud I06 in block'84 through a noddle pin I01 in an arm I08 which is pivoted on a stud I09 in frame I9. Rod I05 is provided with two collars H0 and III and a spring II2 to form a resilient connection in one direction between rod I05 and noddle pin I01. A spring rod II3 connected to arm I08 and passing through a hole in stud H4 in frame I9 carries a spring II5 which acts against collar II6 to urge arm I08 toward the right.

Arm I08 is provided with a lug II1 which abuts against an adjustable screw 8 that is received in a threaded hole in a lever I I9 pivotally mounted on pin I20 in a bell crank I2I. limited movement about pin I20, as indicated in Fig. 9. The lever is held in normal operative position, that is with screw H8 in line with abutment II1, by means of a detent device I23 which engages an indentation in hell crank I2I. Lever H9 is also movable to an inoperative position in which screw 8 is out of line with abutment H1, in which position it is held by the detent device I23 engaging another indentation in bell crank IZI.

The other arm of bell crank I2| carries a noddle pin I24 through which extends one end of a rod I25 which is secured against movement in the noddle pin by collars I26. The other end of rod I25 has a head which surrounds a stud I21 in a cam lever I28 having a follower I29 which follows cam 1|. Spring I30 surrounding rod I25 abuts against one of the collars I26 and against a slotted stud |3| for urging follower I29 against the cam.

The action of cam 1|, lever I20, and rod I25 is to move bell crank I2I back and forth about its pivot I09 with each rotation of the cylinders, that is once during each cycle of the press. Owing to the pressure of spring II5, arm I08 tends to follow the movements of hell crank |2I and maintain abutment H1 in contact with screw II8.

Arm I08, however, is arranged to be latched at times in its left hand position, so as not to follow the movement of bell crank I 2| and for this purpose is provided with a hardened plate I32 which is adapted to engage a notch I33 in a latch bar I34 pivoted to the frame at I35 and pressed downwardly by a spring I36. The free end of latch bar I34 is connected by a link I31 to the armature I38 of a solenoid I39 secured to the frame I9 by bolts I40. The coil'I4I of the solenoid is adapted to be energized by electrical power, preferably of low voltage, supplied by lead wires I42, I43, from a suitable source, not shown. One of the leads, I42 as shown, is connected-directly to the coil I4I, while the other lead I43 is connected through switching mechanism now to be described to the incoming lead I44 of coil MI.

The two wires I43; I44, pass through an opening I45 in frame I9 and are connected to two metal brushes I46, I 41 which are held in a bracket I48 secured by screws or the like to the inside surface of frame I9. These brushes bear against the surface of a flat annular ring I50 which is fastened to the end ofcylinder I0 by means not shown. Ring I50 is formed of electrically nonconducting material; Inserted in the ring are two metal contact plates I5I, I52 which are adjacent each other but radially spaced so asto pass beneath and into contact with brushes I46, I41, respectively. These plates |,5|,- I52, are connected to wires I53, I54 which lie in grooves formed in the inner face of ring I50, and, at a point adjacent the gap in the periphery of the cylinder I0 pass through an opening I55 in the end wall of the cylinder into the gap. As shown, particularly in Fig. 5, wire I54 is connected to contact point I56 carried on a stud I51 which is secured on a Lever II 9 has when there is no sheet in the gripper 2|, spring I62 will urge arm I6| of the detector finger outwardly between the bifurcations of the gripper 2| until the contact point I59 engages contact point I56. But when a sheet is presented by grippers 24 and gripped by grippers 2| against 7 pad I 83 the sheet will depress arm I" into the recess in pad I83 and cause contact points I58, I59 to separate.

The position of the metal plates II, I52 is preferably so chosen in relation to the position of the gripper 2| and the location of brushes I48, I41, that the plates I5I, I52 will make contact with the brushes I48, I41 very shortly after the gripper 2| has closed upon the sheet, thereby giving ample time for the mechanism controlled thereby to function properly.

I18 represents the feed board of a pile feeder. Sheets are conveyed down this board by tapes in the well-known manner of such feeders. Suitable means for throwing off the feeder action are employed to take effect in case arsheet fails to strike the front registering means on the feed board at the proper time, or in case a sheet approaching the said registering means is crumpled, folded or askew. Figs. 2 and 11 illustrate one means for this purpose.

Front registering means are illustrated at I89, and HI represents a detector finger approximately in transverse alignment with the said registering means. Preferably there are two such fingers spaced transversely of the feed board. The fingers I1| are integral with forwardly projecting fingers I12, these two parts thus constituting a bell crank lever which is pivoted at I13 upon an arm I14 that is pinned to an oscillating shaft I15 and carries the said registering means I89. Gravity tends to move the bell crank counterclockwise on its pivot I13. A second oscillating shaft I18 carries a depending latch bar I11 and a depending leg I18 which is provided with a rearwardly projecting foot I19 having a V-shaped extremity. I

A fixed stud I88 supports a bell crank lever having arms |8I and I82. Arm I8| carries a pad I83 which is adapted to engage the end of latch bar I11, while arm I82 has an articulated connection with a longitudinally movable rod I84 which is subjected to pressure by a spring I85 tending to move the rod forward but prevented by cam action from doing so during the major part of each cycle of the feeder.

{when a properly fed sheet strikes a finger I" the corresponding finger I12 is lifted to the position of Fig. 11, so that when the leg I18 swings rearwardly its foot I19 moves beneath finger I12 and latch bar I11 moves into position above pad I8 3 thereby preventing spring I85 from forcing the, rod I84 forwardly. Arm I14 will then rise because of the oscillation of shaft I15, and the sheet will be fed forward by suitable pull-out rollers or the like.

if on the other hand a sheet should fail to appreach the front stops at the proper time in the cycle of the feeder, finger I12 through the action of gravity will take a position lower than that illustrated, that is until finger I1| bears against a stop I88. In this lower position the forward extremity of finger I12 will engage the V-notch in foot I19 as the leg I18 swings rearwardly, and thus will hold latch bar I11 in the broken line position, or clear of the pad I83. Accordingly, when the previously mentioned cam means permits, spring I85 will drive the rod I84 forwardly, which will function in any known manner to stop feeder action.

I98 represents a sheet transfer device having sheet grippers I9I, this device being preferably a rotary device of irregular motion adapted to take a sheet from the feed board while the sheet is moving at less than press speed and accelerate it to press speed at the time of its transfer to a second constant speed transfer cylinder 28. previously mentioned, which rotates at press speed and is provided with the grippers 24 which are adapted to deliver the sheet to the grippers 2| of the impression cylinder I8.

In the normal operation of the press, a sheet is presented at each revolution of cylinder 8 to the grippers of that cylinder and the closing of gripper 2| on the sheet causes the sheet to move arm I8| inwardly, thereby separating contact I59 from contact I58 and keeping open the circult to solenoid I38 at the time when plates I5l,

I52 pass under brushes I48, I41.

Under such conditions the armature I38 is free to remain in its downward position allowing latch bar I34 to be pressed down by spring I38 into position for its notch I33 to engage plate I32 of arm I88. Under these conditions, bell crank I2I continues to oscillate back and forth at each revolution of the press under the influence of cam 1| acting upon lever I28 and rod I25 but it has no influence upon arm I88 other than to relieve the pressure of plate I32 against notch I33 each time the screw 8 is brought into contact with lug II1 of arm I88 at the leftward end of its stroke.

If, however, there is an interruption in the presentation of sheets to impression cylinder I8, with the result that no sheet is present when gripper 2| closes on pad I83, arm I8| of the detector finger remains in its outward position and contact points I58, I59 remain closed. Shortly thereafter, the rotation of cylinder I8 brings plates I5I, I52 into contact with brushes I48, I41 thereby completing the electrical circuit to solenoid I39 and causing armature I31 to be quickly lifted to the position shown in Fig. 3. This occurs at the time when the pressure of plate I32 on notch I33 has been relieved by cam 1|, as previously described, and causes the unlatching of arm I88 by latch bar I34. Arm I88 is thus free to be pressed by its spring II 5 toward the right and to follow the movement of bell crank I2I under the control of cam 1| Arm I88 in moving toward the right acts through rod I to pull thrust block 84 to the right over against stud 8|. Thereafter on the next upward movement of block 84 stud 8| is raised by shoulder 83 and lever 11 is thereby swung to the left into the position shown in Fig. 3. The corresponding lever 11 on the opposite side of the press experiences a similar movement since both levers 11 are keyed to shaft 18. This movement breaks the toggle between shaft 18 and eccentrics 28 and causes these eccentrics to be rotated somewhat clockwise thereby moving blanket cylinder I I away from plate cylinder The movement of lever 11 toward the left imparts a downward thrust to rod 9| which acts through lever 93 and bell crank (assuming pin I84 is in its normal position in hole I83) and rod 91 to resiliently push thrust block 8| to the left against pin -59 so that, on the next upward movement of block IiI, pin 59 will be lifted by shoulder 82 and lever 55 will be swung toward the right as in Fig. 3. This movement of lever 55 imparts an upward thrust through rod 53 to pin 52 until pin 54 reaches the on toggle position. The upward thrust on pin 52 turns lever 38, and consequently also shaft 39 thereby breaking the toggles on both sides of the press between shaft 39 and eccentrics 32 and giving these eccentrics a slight clockwise rotation to move ments just described, and a sheet isthen pre-,

sented to grippers 2| the mechanism functions to throw the impression on" in the same sequence, that is, the blanket cylinder II moves toward plate cylinder I2 first and toward impression cylinder I second in the same cycle, these movements occurring during passage of the gaps past the lines of centers of their respective cylinders.

When the inner eccentric is operated to throw the blanket cylinder toward the plate cylinder it exerts a wedging action upon the outer eccentric which tends to resist movement of the latter eccentric. Hence the operation of the outer eccentric to shift the blanket cylinder toward the impression cylinder is opposed by this wedging action. However, because of the antifriction hearings on both'sides of the outer eccentric, it is possible to effect the required movement of the latter in spite of the additional load imposed upon it by this wedging action.

Thus, starting with the parts in off position and with impression cylinder I0 approaching the sheet receiving position, the high spot of cam II travels under follower I29, as in Fig. 1, causing bell crank I2I to move arm I08 to the left into latching position. Gripping of the sheet by gripper 2| opens contact points I58, I59 thereby keeping the circuit to solenoid I39 open during the time plates I5I, I52 contact brushes I46, I41. Latch bar I34 thus is permitted to remain in its lower position to latch up the arm I08 so that as follower I29 rides down cam II arm I08 will not be permitted to follow bell crank I2I toward the ri ht.

'I'he leftward movement of arm I08 puts block 84 over against pin 80 so that as the high point of cam 1| comes under follower 88 block 84 pushes pin 80 up and rocks lever 11 into the on toggle" position thereby moving eccentrics 28 counterclockwise and moving cylinder II toward plate cylinder I2.

The rocking of lever 11 to the right raises rod M and thereby moves block 8| to the right against pin 80 so that when the high point of cam II passes under follower I0 block 8| pushes pin 80 upward and moves lever 55 to the left thereby pulling levers 38 down into the on toggle position and moving eccentrics 32 counterclockwise to move cylinder II toward impression cylinder I0.

When it is the desire of the operator to run the press without sheets and with the blanket and plate cylinders in contact, as for rolling up, the blanket in preparation for printing, he first cuts off the electric power to the solenoid I39, as by opening the line switch I99 (Fig. 1), so that the latch bar will not be raised and lever I08 will remain in the latched up position, then he removes pin I04 from hole I03 in lever 93 and moves, or permits gravity to move, bell crank 95 down so that link GI bears against stud 58. Under these conditions, as shown in Fig. 4, the pressure between plate and blanket cylinders remains on while the pressure between blanket and impression cylinders remains off.

"In case it is the desire of the operator to run sheets through the press without pressure of the blanket cylinder against either of the other two cylinders, as when testing sheet feeding and I handling, he merely swings lever II9 about pin I20 to the position in which screw H8 is out of alignment with lug I I! so that movement of lever II9 will have no influence on lever I08, then he lifts latch bar I34 to allow lever I08 to move to the right under the pressure of spring II5 thus .shifting link 84 over against pin 8|. This puts eccentrics 28 in the off position on the next revolution of cam II. If pin I04 is in its normal position in hole I03 the movement of lever 11 will set link 6| to throw off the eccentrics 32. If pin I04 is not in hole I03, link 6| will be set in the latter position automatically by action of gravity as previously mentioned. Under the conditions just described, pressure between all cylinders will remain off regardless of the presence or absence of a sheet in gripper 2I.

When the operator desires to adjust the blanket cylinder toward or away from the impression cylinder I0 in order to accommodate sheets of different thickness or for changing the amount of printing pressure, he turns knob 5| in the proper direction to move shaft 39 toward the right about its pivot M for setting the blanket cylinder closer to the impression cylinder and toward the left for the reverse effect.

The mechanism illustrated in Figs. 2 and 11 serves to stop the operation of the feeder in the event that a sheet fails to strike the detector finger III at the proper time in the feeder cycle. This action conventionally serves to set in motion means for throwing off the impression of the printing press when the sheet last fed has been printed. This of course calls for delayed action mechanism, and where the sheets before being presented to the first impression cylinder must pass over intermediate transferring elements such as the cylinders I and 23 of the illustrated case. such mechanism must be somewhat complex. In accordance with the present invention, however. the impression throwoff is not directly afiected by the feeder throwoff. but is set in operation at the proper time by the failure of the feeder to present a. sheet to the first printing unit.

Having thus described our invention, we claim:

1. In a machine f the character described, a feed table for supporting sheets fed automatically in timed sequence, front registering means associated with said table, a printing press having an impression cylinder, sheet grippers thereon adapted to take sheets advancing from said feed table, impression throw-off mechanism, sheet detecting means associated with said front registering means, means set in motion by said detecting means for stopping the feed of sheets in the absence of a sheet at said front registering means at the beginning of a press cycle, sheet advancing means-forward of said feed table timed to present to said impression cylinder grippers a sheet which has passed said detecting means and is in transit between said feed table and said impression cylinder, and means associated with the grippers on said impression cylinder, functioning in the absence of a sheet fed to said cylinder, for setting said throw-ofi mechanism in impression off position and holding it in that position until the next sheet is fed.

2. In a machine of the character described, a feed table for supporting sheets fed automatically tion with said impression cylinder, said advancing means being timed to present to said impression cylinder grippers a sheet the rear edge of which has passed said front registering means and is in transit between said feed table and said impression cylinder, impression throw-ofl mechanism, sheet detecting means associated with said front registering means operable to stop the feed of sheets, and means associated with the grippers on said impression cylinder, functioning in the absence of a sheet fed to said cylinder, for setting said throw-oil mechanism into operation.

3. In a machine of the character described, a feed table for supporting sheets fed automatically in timed sequence, front registering means associated with said table, a printing press having an impression cylinder, sheet grippers thereon, sheet advancing means forward of said table comprising a plurality of sheet transfer devices timed to present to said impression cylinder grippers a sheet the rear edge of which has passed said front registering means and is in transit between said feed table and said impression cylinder, impression throwofl mechanism, sheet detecting means associated with said front registering means operable to stop the feed of sheets, and means associated with the grippers on said impression cylinder, functioning in the absence of a sheet fed to said cylinder, for setting said throw-off mechanism into operation.

4. In mechanism of the character described, a

frame, plate, blanket and impression cylinders, a pair of outer eccentrics, roller bearings for said outereccentrics mounted in said frame, a pair of inner eccentrics carried by said outer eccentrics, the shaft for said blanket cylinder being mounted in said inner eccentrics, impression throwofl means functioning to turn one pair of said eccentrics to separate the blanket cylinder from the plate cylinder, and impression throwoff means set in operation by the actuation of said first named throwoif means for separating the blanket cylinder from the impression cylinder in the same cycle of the press.

5. In mechanism of the character described, a frame, plate, blanket andimpression cylinders, a pair of outer eccentrics, roller bearings for said outer eccentrics mounted in said frame, a' pair of inner eccentrics, roller bearings for said inner eccentrics carried by said outer eccentrics, the shaft of said blanket cylinder being mounted in said inner eccentrics, and impression throwoff means functioning to turn said pairs of eccentrics in sequence, said means comprising means for turning the second pair of eccentrics set in motion by the means for turning the first pair.

6. In mechanism of the character described, a frame, plate, blanket and impression cylinders, a pair of outer eccentrics, roller bearings for said outer eccentrics mounted in said frame, a pair of inner eccentrics carried by said outer eccentrics, the shaft for said blanket cylinder being mounted in said inner eccentrics, cam actuated means for turning said inner eccentrics first and said outer eccentrics thereafter in sequence during a press cycle to throw off the blanket cylinder from the plate cylinder first and from the impression cylinder second, and means settable in advance to disable said means for turning said inner eccentrics, whereby the blanket cylinder will remain in conl2 tact with the plate cylinder but will be thrown off from the impression cylinder.

7. In mechanism of the ,character described, a frame, plate, blanket and impression cylinders, a pair of outer eccentrics, roller bearings for said outer eccentrics mounted in said frame, a pair of inner eccentrics carried by said outer eccentrics, the shaft for said blanket cylinder being mounted in said inner eccentrics, impression throwofl means functioning to turn said inner eccentrics to throw said blanket cylinder toward said plate cylinder, and impression throwoif means set in operation during the same cycle by said first named throwofi means for turning said outer eccentrics in their roller bearings to throw said blanket cylinder toward said impression cylinder.

8. In mechanism of the character described, a frame, plate, blanket and impression cylinders, a pair of outer eccentrics mounted in said frame, a pair of inner eccentrics carried by said outer eccentrics, the shaft for said blanket cylinder being mounted in said inner eccentrics, impression throwofi means functioning to turn first said inner and then said outer eccentrics for moving said blanketcylinder relative to said plate and impression cylinders in sequence in the same press cycle, said second throwoff means functioning in response to the action of said first throwoif means, and means interconnecting the eccen-. trics of one of said pairs and operable at a single operating station to adjust the angular position of the latter eccentrics.

9. In throw-off mechanism for a printing press, an adjustable mounting for the shaft of a cylinder, a toggle lever one end of which is connected with said adjustable mounting, an anchor pivot for the opposite end of said lever, an arm pivoted at one end, a movable mounting for said anchor pivot at the opposite end of said arm, means for shifting the intermediate pivot of said toggle lever to on toggle or off toggle" position, a link to one end of which said movable mounting is connected, an eccentric bearing for the opposite end of said link, and means for turning said eccentric bearing to adjust the position of said movable mounting.

10. In throw-off mechanism for a printing press, an adjustable mounting for the shaft of a cylinder, a toggle lever one end of which is connected with said adjustable mounting, an anchor pivot for the opposite end of said lever, an arm pivoted at one end, a movable mounting for said anchor pivot at the opposite end of said arm, means for shifting the intermediate pivot of said lever to on toggle," or "ofi toggle position, a link to one end of which said movable mounting is connected, an eccentric bearing for the opposite end of said link, and non-reversible means for turning said eccentric bearing to adjust the position of said movable mounting.

11. In throw-off mechanism for an offset printing press, a pair of outer eccentrics, a pair of inner eccentrics carried by said outer eccentrics,

a blanket cylinder journaled in said inner eccentrics mechanism for throwing off the blanket cylinder from the plate cylinder, separate mechanism for throwing off the blanket cylinder from the impression cylinder, means adapted to be actuated by the throw-off from said plate cylinder for setting in operation the throw-off from said impression cylinder, said means comprising twin elements one of which is adapted to be driven and the other of which is adapted to drive, and detachable means for connecting said twin elements together, whereby the removal of said asvsnoo detachable means disables said throwoff mechanism.

12. In throw-oi! mechanism m printing presses, a toggle lever arranged when thrown to "toggle on position to move a cylinder to on position and maintain it there, an adjustable anchor pivot for said toggle, a. second toggle operatively connected to said first toggle for moving said first toggle from one position to the other, a fixed anchor pivot for said second toggle, and a swingable thrust block for operating said second toggle in either direction.

13. In throw-off mechanism for printing presses, a toggle lever arranged when thrown to toggle on position to move a cylinder to on position and maintain it there, and adjustable anchor pivot for said toggle, a second toggle operatively connected with said first toggle for shifting the first toggle to "toggle on" position when the second toggle is moved to- "toggle ofi" position and vice versa, a fixed anchor pivot for said second toggle, and a swingable thrust block for operating said second toggle in either direction.

14. In throw-oil mechanism for printing presses, a printing couple comprising a rotating cylinder, sheet grippers thereon, a feeler on said cylinder adapted to be shifted by a sheet when gripped by said grippers, an electric circuit opened by said feeler when shifted, a second cylinder, means for moving said second cylinder to on or off position comprising a toggle lever, a swingable thrust block for causing said toggle to assume either "toggle on or toggle ofl" position, a throw-oil control for swinging said thrust block from one position to the other, a latch adapted to hold said control and said thrust block in position to maintain said toggle in impression on position, magnetic means responsive to cur-- rent in said circuit for disabling said latch, and means for moving said unlatched control to swing said thrust block to position for causing said toggle lever to assume impression off position,

and cam means operable to return said throwofl gaged by roller bearings, and means for turning one of said pairs of eccentrics to press said blanket cylinder against said plate cylinder and tor thereafter while pressure is maintained 14 against said plate cylinder turning the other pair of eccentrics to press said blanket cylinder against said impression cylinder.

16. A printing unit adapted for use in a multi unit press, said unit embodying a plate cylinder, a blanket cylinder and an impression cylinder, said blanket cylinder being disposed between said plate and impression cylinders with its axis to one side of the plane through the axes of the plate and impression cylinders, impression throwoff mechanism effective to move said blanket cylinder out of contact with said plate and im pression cylinders in sequence, means compris ing a. feeler on said impression cylinder functioning in the absence of a sheet fed to said cylinder for setting said throwofi mechanism to move said blanket cylinder out of contact with said plate cylinder and thereafter out of contact with said impression cylinder, said means finictioning also to return said blanket cylinder ta impression on position relative to said plate and impression cylinders in sequence during the cycle following the taking of a correctly fed sheet by said grippers, cam and cam follower means timed to cause said sequentiai action to be completed in a fraction of one revolution of said impression cylinder, and means for placing each sheet on the impression cylinder more than said fraction of revolution ahead of the printing line, and transfer means for taking sheets from said impression cylinder and advancing them to the next unit of the press.

CHARLES W. HARROLD. ARTHUR B. WOODRU'FF.

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

UNITED STATES PATENTS Number Name Date 1,193,045 Niles Aug. 1, 1916 1,327,182 Upham Jan. 6, 1920 1,351,175 Lehr Aug. 31, 1920 1,374,137 Blaine Apr. 5, 1921 2,003,798 Barber June 4, 1935 2,018,282 Robinson Oct. 22, 1935 2,100,852 Jacobson Nov. 30, 1937 2,146,963 Lang Feb. 14, 1939 2,356,058 Hunting Aug. 15, 1944 2,356,315 Gudger Aug. 22, 1944 2,419,403 Horton et al Apr. 22, 1947 FOREIGN PATENTS Number Country Date 224,843 Great Britain Nov. 20, 1924 500,600 Great Britain Feb. 13, 1930

Images