US2564591A - Sheet feed interrupter means for printing presses - Google Patents

Description

R. F. ABERLE Aug. 14, 1951 SHEET FEED INTERRUPTER MEANS FOR PRINTING PRESSES I Original Filed Sept. 20, 1946 5 Sheets-Sheet 1 an" A R. F. ABERLE Aug. 14, 1951 SHEET FEED INTERRUPTER MEANS FOR PRINTING PRESSES 5 Sheets-Sheet 2 Original Filed Sept. 20, 1946 frpayezzfor H0 .EdZerle m, Z M 11 c 7: T a W SHEET FEED INTERRUPTER MEANS FOR PRINTING PRESSES Original Filed Sept. 20, 1946 R. F. ABERLE Aug. 14, 1951 5 Sheets-Sheet 5 familiar .2? aderle R. F. ABERLE Aug. 14, 1951 SHEET FEED INTERRUP'I'ER MEANS FOR PRINTING PRESSES Original Filed Sept. 20, 1946 5 Sheets-Sheet 4 R. F. ABERLE 64, SHEET FEED INTERRUPTER MEANS For: PRINTING PRESSES Aug. 14, 1951 5 Sheets-Sheet 5 Original Filed Sept. 20, 1946 Patented Aug. 14, 1'95 SHEET FEED INTERRUPTER MEANS FOR PRINTING PRESSES Roy F. Aberlc, Portia Southworth Machine Maine, a corporation of Original application nd, Maine, assignor to Company, Portland,

Maine September 20, 1946, Serial No. 698,252. Divided and this application April 9, 1948, Serial No. ber 18, 1947 v 2 Claims.

This invention relates to printing presses and more particularly to sheet-fed, lithographic, ofiset presses of the kind illustrated in my co-pending application Serial No. 698,252, filed September 20, 1946 which has matured to Patent No. 2,542,073, granted February 20, 1951, of which this application is a division. The principal object of the invention is to provide improved control of the feedingmeans for delivering the topmost sheet from a stack of sheets to be printed to the printing couple of that press. Other ob- Jects are to provide means for automatically discontinuing operation of the feeding means in the absence of a sheet between the constituent rolls of the printing couple, and other means for controlling operation of the feeding means independently of the presence or absence of a sheet at the printing couple.

As herein illustrated, pneumatic means in the form of a nozzle is arranged to lift the topmost sheet from the stack for transfer to the printing couple. A sub-atmospheric pressure is maintained in the nozzle by an electric motor-driven pump connected thereto and operation of the motor and hence maintenance of the low pressure in the nozzle is effected in accordance with the presence or absence of sheets to be printed 20,088. In Canada Septembetween the printing couple or independently thereof by a circuit connecting the motor to a source of electric power. The electric circuit includes a holding circuit for maintaining the motor in continuous operation once it has been ini-,

tiated and sheets continue to be fed to the printing couple, a manually operable starting switch to initiate operation of the motor, a manually operable stopping'switch to stop the motor if desired, regardless of the presence or absence of sheets in theprinting couple, a switch automatically operable to stop the motor in the absence of sheets, operation of this latter switch being effected by separation of the printing couple, and a manually operable switch for maintaining the holding circuit intact independently of this last switch which is actuated by separation of the printing couple.

In the drawings: v

Fig. 1 is a diagram showing the main rolls of the press;

Fig. 2 is a vertical sectional view of the press taken from .the opposite point of view from Fig. 1 and looking outward toward one of the side frames, showing especially the mechanism for applying pressure to the ofiset cylinder, many of .-.the mechanisms of the press being omitted;

Fig. 3 is a view similar to Fig. 2,0n a larger to separation of the main and offset cylinders;

Fig. 4 is a fragmentary vertical sectional view taken on the line 44 of Fig. 2 on a larger scale;

Fig. 5 is a fragmentary vertical sectional view on the line 5-4 of Fig. 4;

Fig. 6-is a diagram in the nature of a side elevation of the paper stack and paper stack platform of the feeding apparatus for use with the press;

Fig. 7 is a diagram in the nature of a plan view of a fragment of the feeding apparatus of Fig. 6;

Fig. 8 is a diagram of control circuits for many of the elements of the press;

Fig. 9 is a diagram showing the control of the feeder pump motor.

The improved control for the sheet feeding means is especially adapted to be used in combination with the sheet feeding mechanism shown in my Patents Nos. 2,497,849 and 2,542,073.

Referring to Fig. 1, the main frame of the press includes opposite interconnected side plate sections 25 which are preferably flanged as at 25* at their lateral margins (Fig. 2), the flanges serving to cover and protect various gears, chains. bearings and control mechanisms that are located adjacent to the two side plates 25.

Sheets fed successively by feeding mechanism such as that of said applications enter the machine from the right as shown in Fig. 1, and are gripped by gripper fingers on a gripper bar 33 carried by chains I to a printing couple. The course of chains I80 is indicated in Fig. 1. U r

The sheet is carried by the traveling gripper bar 33 to and partly around a rubber covered offset cylinder 40 which constitutes one component of the printing couple, the offset cylinder having a recess adapted to receive the gripper bar.

As shown in Fig. 1 offset cylinder 40 cooperates with a main cylinder indicated generally at 42 which constitutes the other component of the printing couple. Main cylinder 42 comprises opposite end portions 42 mounted on a shaft I66, a lithographic plate holder segment 43 having hub portions 43 also mounted on the shaft I66, and an interchangeable impression segment 44 detachably secured to the opposite end portions 4!. Depending upon the character of the work being done, impression segments having surfaces of various materials may be used as more fully described hereinafter.

As explained in theabove patents a lithographic plate on segment 43 offsets an image onto segment 33 of the main cylinder, which results in the image being printed from the offset cylinder 33 onto the lower surface of the sheet.

The timing and arrangement of the main and offset cylinders and the feeding mechanism, is such that a sheet to be printed is presented to the nip between the offset and main cylinders at each revolution of the main cylinder, at each second revolution of the offset cylinder.

The driving connections for the main printingor in other words,

couple and for the other parts of the machine are through adjustable tappets 323, to support der to move away from the main cylinder, and

rotation of the control shaft 323 in a clockwise direction lifts the offset cylinder and forces it under pressure against the main cylinder.

A sliding collar 333 (Fig. 4) on shaft 323 car- .ries a horizontal connecting pin 33! which is guided through a slot in an arm 332' which extends from a fixed collar 332 on shaft 328. Con-- necting pin 33l is adapted to be projected to the right in Fig. 4 to a podtion in which it under lies a shoulder 334 on a vertically reciprocable pressure fork or plunger 335.

A cam follower roller 333 (Figs. 2 and 3) on the pressure fork 335 is adapted to be contacted by cam surface 338 of a cam 3l3 mounted on the shaft I83 of the main cylinder. to apply pressure to the pressure fork or plunger 335 at each rotation of the main cylinder.

The connecting pin lll is urged in the left in Fig. 4 by a spring 333 which acts on the slidable I collar 333, tending to' disengage the pin 33! from the pressure fork shoulder 333. thus allowing the I pressure fork or plunger 335 to move idly.

A solenoid 332 (Fig. 3.) has its'movablearmature 343 connected by a flexible cable 3 to the slidable collar 333. Energization of the solenoid 332 by means of a push-button switch 342 (Fig. 8) thus pulls the pin lll to the right in Fi 4,

carrying it into the path of the pressure fork shoulder 334.

During continued printing, the pressure of pressure fork shoulder 333 upon the pin 33l retains the pin under this shoulder against the action of the spring 333'. thus keeping the pressure fork connected to the pressure control eccentric shaft 328 as-long as the pressure fork is sufficiently low in position for, the shoulder 33! to bear against the pin lll.

The shape of the cam 333 on the main cylinder shaft is such that the high part of the cam surface 338 bears against cam follower roller 333. only during the. presentation of the plate segment 3 to the oifset cylinder.

In normal printin pressure between the offset cylinder and the impression segment 43 is secured by latching the pressure fork in a pressure-applying position by detector-controlled latch mechanism.

A latch 353, Fig. 5, is slidably mounted in a block 35l and includes a bevelled portion 352 adapted to slide into a wedge shaped recess 353 in the pressure fork 325. Latch 353 is normally urged to the right or unlatched position in Fig- 5 4 by a spring 355, but upon the detection of feed of a sheet to the press, latch 353 is urged to the left and into the recess 353 by a bell crank 351 which is connected by a flexible connection 358 to the movable armature 353 of a solenoid 383 as shown in Fi 2. I

Solenoid 360 is energized by the interruption of a light beam by a sheet as the sheet is carried toward the offset cylinder by the gripper fingers 32 and gripper bar 33.

In Fig. 2 a source of light such as an electric lamp is indicated-at 313 and a photo-electric cell normally exposed to the light beam is indicated at 3', the beam of light from lamp 313 to cell 31! being adapted to be interrupted by a properly fed sheet carried by the gripper bar 33 passing along the upper run of chain I33.

Referring to the wiring diagram of Fig. 8, solenoid 368 is normally de-energized and is adapted to receive its operating current through a circuit which includes the terminals D and F. of a relay I D and F and sending an impulse through the circuit which includes the solenoid 383.

This energization of relay 333, and consequently of the solenoid 363, takes place during the offsetting portion of the cycle, that is, while the image from the lithographic plate on segment 43 is bey ing transferred to the offset cylinder, and hence while the pressure fork 325- is held in its depressed position of Fig. 5 by the highsurface 338 of the cam 339. The notch 353 is accordingly in position to receive the latch 353.

The block 35l which carries the latch 353 is vertically slidably mounted in a stationary guide bracket 383 (Fig. 4) and a screw 334 which is ro-' V tatable in the bracket 383 is threaded into the block 35L A rod consisting of jointed portions 385, 383 and 38'! (Figs. 4 and 2), fastened to the screw 333 and to a knob 388, enables the screw 384 to be turned to adjust the level of the block 35! and hence the level at which the latch 353 -will' hold the pressure fork during proper presentation of a sheet between the cifset cylinder and impression segment.- Normally the latch-carrying block l5| will be adjusted at such level that the latch 353 will have at least a slight clearance from the bottom surface of notch 353 as'the latch enters the notch during the offsetting portion of the cycle.

when a properly fed sheet passes and interrupts the light beam at a time near the. end of the offsetting portion of the cycle, the solenoid 3" insertsthe latch in the notch 353and holds it there until thelatch is caught and held by the bottom surface of the notch when the cam surface 333 ceases to apply downward pressure tc the pressure fork. When the trailing end of the sheet subsequently passes the lightbeam, the solenoid 383 becomes deenergized.

If a sheet fails to be fed. the solenoid 333 will be energized as a result of interruption of the light beam by the passing empty gripper bar, but

will become de-energized while the cam surface 333 is still applying downward pressure to hold the pressure fork in its lowest position. The latch then is removed from the notch by the spring 355 while the cam surface 338 is still active, .and at the end of the ofisettingportion of the cycle the pressure fork is not latched but is free to rise considerably higher than if it were latched. The

Moreover, when the pressure fork fails to be latched by the latch 350, the shoulder 324 of the pressure fork will move higher than will the con-. necting pin 33I, breaking the normal frictional contact between these parts, whereupon the spring 340, Fig. 4, will pull the pin 33l out from under the shoulder 334. Succeeding strokes of the pressure fork will thereupon be idle and the offset cylinder will remain out of contact with the main cylinder until the solenoid 342 is re-energized by manual operation of the switch 342-- It will be observed that in the normal operation of the press, while sheets are being normally fed, the pressure fork or plunger 335 moves only through so much of its stroke as effects the relatively slight separation and approach of the axes of the offset cylinder and the main cylinder appropriate to the successive presentation of the plate segment and impression segment to the 011- set cylinder..

Interruption of the light beam B from the lamp 319 to the photoelectric cell 31! by the gripper bar 33 as the latter travels along the lower run of the chains I80 can be avoided by disposing the light beam so that it is not crossed by the gripper bar in this lower run of the chains. This may best be accompanied by locating the lamp 310 and cell 3H as indicated in Patent No. 2,542,073 mentioned above, with both the lamp and cell outside of the courses of the chains I 89, but with one of these elements, for instance the lamp, somewhat above the other of these elements in such manner that the beam B crosses the line of travel of the gripper bar only at the upper run of the chains I30.

The control of'various parts of the press, and more especially the latch solenoid 360, by the interruption of the light beam B by the sheet being fed, involves certain further relations of the light beam to the press which may be summarized as follows:

The light beam is in a position such that the sheet being fed interrupts the beam while the lithographic plate segment 430i the main cylinder is active, during the time the latch 359 is neither held in latching position by the pressure fork 325 nor held outv of latching position by the pressure fork 325. As indicated above, during the presentation of the plate segment to the offset cylinder the notch 353 in the pressure fork is located so as to permit free movement of the latch 350 into or out of latching position.

The point of interruption of the light beam by the paper is sufliciently near to the line of printing contact between the main and offset cylin ders to permit relatively short sheets to reach the line of printing contact and be gripped between the main and offset cylinders before the light beam is reestablished after passage of the sheet and the latch solenoid 360 accordingly deenergized.

The point of interruption of the light beam by the paper is however sufliciently spaced from the line of printing contact so that the interrupting effect of an empty gripper bardoes not persist up to the time that the impression segment becomes active, but on the contrary the beam is re-established and the latch solenoid 380 is deenergized in time to let the latch all may. out

of the notch 353 before the impression segment is presented to the offset cylinder;

These conditions are best provided for in the 1 press herein shown by locating the light beam 13 so that it is approximately 4" from the line of printing contact between the main and offset 3 cylinders at the point where the beam is interrupted by the paper. 1

Numerous operations of the machine are controlled by a limit switch indicated at 399 in Fig. 4 which preferably constitutes a single throw gang switch comprising switches 390, 399" and399. which control various circuits as shown by the wiring diagrams of Figs. 8 and 9. The limit switch 390, including its three component switches, is responsive to the application of pressure to the offset cylinder, normally tending to open, but being closed whenever the oifset'cylinder is held up in position to press against the main cylinder. Since, as indicated above, the pressure of the offset cylinder is released when failure of feed is detected, the various operations of the machine which are controlled by the switches 390 399 and 390 are also controlled by the detection of failure of feed. It should be explained here that the employment of three limit switches 390 390 and 390 rather than a smaller number of such switches, is described herein in the interest of simplicity. All three of these limit switches act simultaneously in response to the release and application of pressure at the offset cylinder. The skilled electrician will be able to cause a lesser number of limit switches to exf ercise the same controlling functions by utilizingmore complicated, or apparently more complicated, controlcircuits. V

A vertically movable rod 394 is pivotally connected to an arm 332 constituting a projection from collar 332, and rod 394 and has fastened thereto near its bottom end a bracket 395 adapted to depress a cam follower roller 396 on an operating arm 391 of the limit switch 399. The adjustment of the switch and rod 394 is such that in the pressure applying positions of the offset cylinder the limit switch 390 is closed. A

spring 398 may be provided to assist the upward return of rod 394 and bracket 395 upon release of a the latch 359.

As indicated above, the several switches which comprise the gang limit switch 390 control several of the operations of the press. Switch 390-,- when open as indicated in Fig. 8 as in the event of disconnection of the pressure fork and offset cylinder, breaks the circuit through the latch solenoid 360. This renders the latch 350 incapable of moving'to latching position until the offset cylinder has first been connected. to the pressure fork by means of the pin 33l by manual operation of the push-button switch 342 and the offset cylinder brought again into pressure relation to-the main cylinder. i

Thus it is assured that the pressure fork, while disconnected from the offset cylinder, will be capable of rising during each revolution of cam 339 sufliciently high so that it is possible to project the pin 33l into the path of this shoulder 334 for reconnection of the pressure fork andvoilset cylinder.

press. The foregoing mechanism is constructed as described in my Patent 2,497,849, which may be referred to for a more detailed description. Fig.

-' bracket 85 which is slideably mounted on guide bars 00.

Sheets are lifted singly and in succession from top of stack I2 by reciprocating suction picker nozzles 56 which move downwardly and upward- 1y through gaps between successive sets of the cords I8, picking up the trailing end portion of p ,the top sheet, lifting this trailing end portion above the path of travel of the next set of. cords I8, and holding it there until such set of cords I complete the separation of the sheet from the stack. The suction in the nozzles 56 is then broken and the traveling cords I8 advance the 1 sheet into the press.

Lifting of the sheets is facilitated by intermitface of the stack of Fig. 6 by air blast nozzles I40, such blasts of air fanning out the top several 1 sheets of the stack and accomplishing the first part of the elevation of the trailing edge portion of the top sheet.

Suction is supplied to the nozzle 66 through flexible tubes 83 (Figs. 6 and 9), a suction header conduit conduits 16 and 15, and a mechanically controlled valve 14 which breaks the suction at the proper times, a conduit 13, and a fiexible coupling 13 which leads to the suction side of a motor-driven air pump indicated diagrammatically at I060. Air is supplied under pressure to the nozzles I40 from the pressure side of the pump I060 (Fig, 9).. under the control of a mechanically actuated piston valve I6I.

In accordance with this invention press is provided with means for automatically stopping feed of sheets when a sheet fails to be properly fed. and in the preferred form of such mechanism, indicated in the diagram of Fig. 9, a feed of sheets is automatically stopped as a result of separation of the combined plate and impression cylinder and the offset cylinder. Provision is also preferably made for permitting feed of the sheets tent blasts of air directed against the upper right I notwithstanding the separation of the combined v and offset cylinders.

As indicated in the diagram of Fig. 9, the air pump I060, which provides suction for the picker nozzles 66 and air pressure for the air blast nozzles I40, is driven by an electric motor I06I ree ceiving its current through contacts I066, I065 and I066, I066 of a magnetically closed switch I010. A push button starting switch I012 is adapted to energize the magnetic coil of switch I010 to cause the circuit of the feeder motor to become closed through contacts I066 and I066. Closing of the motor switch contacts I066 and I066 is also accompanied by closing of holding circuit contacts I016 and I016 adapted to establish a holding circuit through the magnetic coil of switch I010 and through a push button stop switch I018, thus to maintain the motor circuit closed after release of the starting switch I012 and permit the motor to be stopped by pressing the stop switch I018. e

The limit switch 300 which opens, as previously explained, when pressure is not applied to the offset roll, is interposed (Fig. 9) in the holding circuit of the motor switch I010. A manually operable switch I018 is also interposed in this holding circuit, in parallel with the limit switch 300.

With the manual switch I019 closed, the holding circuit will be automatically established through the switch I010 upon closing the push button starting switch I012, notwithstanding the limit switch 390 may be open as a result of separation of the main and offset cylinders. With the press and the conveyor of the feeder running, and the feeder pump motor also workin sheets may be fed through the press in order to make certain that all partsxof the press are properly adjusted to accommodate the sheets.

,Closing the switch I142 Fig. 8, will energize the solenoid 342 to effect connection between the pressure fork 325 and the offset cylinder, and thus bring the offset cylinder into pressure relation to the combined cylinder, whereupon printing will begin and the several limit switches including limit switch 390 will close. Thereupon the operator can open manual switch I019, Fig. 9, and further operation of the feeder pump motor will depend upon limit switch 390 remaining closed. At any time thereafter at which a sheet fails to be properly fed, and the offset and combined cylinders separate, limit switch 390 will open and automatically stop the feeder pump motor I06I and feeder air pump I060. This feed of further sheets is thus instantly stopped, although the pickers 66 and conveyors of the feeder continue to be driven in timed relation to the main cylinder and the various conveyors of the press by the driving connections described in said Patent No. 2,497,849.

Many of the elements of the control circuit and their functions have been described above. Re-

ferring to Fig. 8, a suitable alternating current line is shown as adapted to supply current to the electric lamp 310, the photoelectric cell 31I, the photoelectric relay 380 and a photoelectric ampliflcation network indicated diagrammatically at I090, under the control of the manually operated switch I09l.

The photoelectric amplification network I000 is of such character as to transmit amplified current to the relay 380 such as to close the circuit between contacts D and F upon the interruption of the beam of light normally cast by lamp 310 upon the cell 31 I.

The cell 31I, relay 380 and network I030 may for example together constitute the device known as the General Electric Company "Photoelectric Relay C R 7505 K 100 G 2, only those parts of that device that are necessary for an understanding of this invention being shown-herein.

As explained above, the push-button switch 342 is depressed to energize solenoid 342 to pull the pin 33I to the right in Fig. 4, carrying it into the path of the pressure fork shoulder 334, thus effecting an initial connection between the pressure fork and the offset cylinder, a connection which is maintained by pressure of the pressure fork shoulder 334 upon the pin 33I until failure of a sheet to be fed causes the latch 350 to fail to be engaged and held in the recess 353 of the .pressure fork.

The operator can release the push button switch 342 as soon as a properly fed sheet has caused the latch 350 to hold the .pressure fork.

Failure of feed of a sheet causes release of pressure upon the ofiset cylinder and causes limit switches 390 and 390 to open.

The open condition of limit switch 300' (Fig. 8) prevents energization of solenoid 360 and prevents latching of the pressure fork in its lower or pressure-applying position unless theoflset cylinder has been moved into pressure relation to I the main cylinder by means of the connecting pin The open condition of limit switch 390 (Fig, 9) breaks the holding circuit of the feeder pump motor switch (unless the manual switch I019 is closed), and so stops the feed of sheets. Feed of sheets may, however, be carried on in the open condition of limit switch 390 by having the switch I019 closed.

I claim:

1. In a sheet-fed printing press, a pair of cylinders comprising a printing couple, means for feeding sheets to said couple, said feeding means including pneumatic sheet-elevating mechanism for lifting a portion of the top sheet from a stack of sheets to be printed, a pump adapted to energize said pneumatic sheet elevating mechanism. an electric motor for driving said pump, a switch controlling the current supply to said motor, a magnetic holding circuit adapted to retain said switch closed, means for automatically separating said cylinders upon failure of feed, second and third switches interposed in said holding circuit and means for automatically opening said second switch to break said holding circuit upon separation of said cylinders, said third switch being manually operable to maintain the holding circuit intact independently of the position-of said second switch.

2. In a sheet-fed printing press, a pair of cylinders comprising a printing couple, means for feeding sheets to said couple, said feeding means including pneumatic sheet-elevating mechanism for lifting a portion of the top sheet from a stack of sheets to be printed, a pump adapted to energize said pneumatic sheet elevating mechanism, an electric motor for driving said pump, a switch controlling the current supply to said motor, a magnetic holding circuit adapted to retain said switch closed including a manually operable push button starting switch to make the circuit, a manually operable push button stopping switch for breaking the circuit, a first switch automatically operable by separation of the cylinders to break the circuit and a second switch associated with the first switch manually operable in conjunction with said first switch in one position to break the circuit and in another position to maintain the circuit independently of said first switch.

ROY F. ABERLE.

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

UNITED STATES PATENTS Name Date Dexter Oct. 18, 1904 Tauscher Feb. 1, 1921 Kelly Dec. 31, 1929 Johnson Aug. 31, 1937 Number

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