US2756672A

US2756672A - Automatic controls for rotary offset printing machines

Info

Publication number: US2756672A
Application number: US323011A
Authority: US
Inventors: Harvey F George
Original assignee: Davidson Corp
Current assignee: Davidson Corp
Priority date: 1952-11-28
Filing date: 1952-11-28
Publication date: 1956-07-31
Anticipated expiration: 1973-07-31
Also published as: DE1744443U

Description

July 31, 1956 H. F. GEORGE 2,756,672

AUTOMATIC CONTROLS FOR ROTARY OFFSET PRINTING MACHINES Filed Nov. 28, 1952 5 Sheets-Sheet 1 W'i I W HE INVENTOR HARVEY F GEORGE ZMWMMM ATTORNEY H. F. GEORGE July 31, 1956 AUTOMATIC CONTROLS FOR ROTARY OFFSET PRINTING MACHINES Filed Nov. 28, 1952 5 Sheets-Sheet 2 INVEN TOR HARVEY F. GEORGE A TTORNEY H. F. GEORGE July 31, 1956 AUTOMATIC CONTROLS FOR ROTARY OFFSET PRINTING MACHINES Filed NOV. 28, 1952 5 SheetsSheet 3 All July 31, 1956 H. F. GEORGE AUTOMATIC CONTROLS FOR ROTARY OFFSET PRINTING MACHINES 5 Sheets-Sheet 4 Filed Nov.

INVEN TOR HARVEY E GEORGE 9 5? 121%....

ATTORNEY H. F. GEORGE July 31, 1956 AUTOMATIC CONTROLS FOR ROTARY OFFSET PRINTING MACHINES 5 Sheets-Sheet 5 Filed Nov.

mm. 88 Rot 30; mm 1 5553 R QR zokkam .EFC E R g 6 f my H V R M A H A Q 3 D7 QOBQQ QQKQQ QMWK .WHNQQ \Qx QQX a A TTORNEV United States Patent "ice AUTOMATI'C'CONTROLS FOR ROTARY OFFSET PRINTING MACHINES Harvey F. George, Richmond Hill, N. Y., assignor to Davidson Corporation, a corporation of Illinois Application November 28, 1952, Serial No. 32'3,01'1

'20 Claims. (Cl. t 101-144)- This invention relates to printing machines, and more especially, to automatic c'ontro'ls for these machines whereby certain operations preliminary to printing are performed before initiating the feeding of sheets to the printing couple, and the power tothe machine is cut off after the printing of the desired number of sheets, all without the supervision of an operator.-

The present invention is particularly applicable to'offsetmachines of this class wherein it is necessary to initially apply dampening solution to the plate before applying the ink to assist in making the non-printing areas of the plate ink-repellant. The extent of initial dampening requireddepends upon factors known-to those skilled in the art. Such factors include atmospheric conditions and, above allelse, the type of printing plate in use. Certain: types of printing plates require more initial dampening thanothers, for example, paper plates require more than metal plates. Consequently, it is customary to run the machine for a given number of. cycles with the dampening rollers in operative contact with. theplate and the inking rollers suspended out of contact therewith before starting the feeding of sheets to the printing couple.

According to the present invention, it. is possible to set the machine for a certain number of preliminary dampening revolutions, as well as for the number of sheets which it is desired to print. During the preliminary dampening. revolutions, the ink rollers are held out of contact with. the printing plate,- and the sheet feeding mechanism is rendered inoperative. When the preliminary dampening revolutions have been completed, the inking: rollers are automatically lowered into inking contact Withthe plate and the sheet feeding mechanism. is started. The printing of sheets c'ontinue's'unti the; desired' number has been printed, at which time the power to the machine is cut off and the machine is rendered inoperative.

It is evident that the-automatic control: featuresof the present invention relieve the operator of the necessity of attending personally to the preliminary dampening runs and permit him: to leave the machine entirely and directhis attention to: other matters. Moreover it is not necessary for him to return to the machine foranypurpose until the printing: run has been entirely completed. These features offermany time saving advantages which willbe especially appreciatedin systems work where it is desirable to' perform a great many short run printing operations inthe least possible time and with a minimum of supervision.

The various novel features and operating arts comprising the present invention will be more fully set fer'th" in the accompanying drawingsand the detailed description which follows:

Referring to the drawings:

Fig. 1 is a left side elevation of the printing; machine, including the sheet feeding means, equipped with-the present invention.

2,756,672 Patented July 31,1956

. 2 regulating" the machine for a given number lininary dampening revolutions.

Fig. 2B'isl a top' plan viewo'f Fig. 2A.

of pre- Fig. 2C is an enlargedside view of certain of the part's' shown in Fig. 2A.

Fig. 2D isaview' approximately along the line 213 413 of Fig' 2B, looking" in the direction ofthe arrows.

Fig.- 3A is a'sideelevation of themeeha'nism for con trolling the operation-of the inking rollers.

Fig. 3B is" an enlarged side elevation of certain ofthe mechanism sh'own inFig; 1.

Fig. 3C is: a view taken-along the-line" 3C-'3Cj of Fig. 3B, looking-in: the direction of the arrows.

Fig. 4A is aright sideelevation of a portionof the feeding mechanism,illustrating the mannerin Whichthe present invention controls the feeding-of sheets.

Figs. 4B and 4C are perspective and front views; respectively, of Fig'i' l-A.

Fig; 5 is a diagram of the control circuit for the present invention.

The present invention is shown and describedin con-' permits the printingtcy-l-inder 1 to be moved into and: out

of tangential. printingv relation; with ing' cylinder 2. p

The machine is capable; of. doing both directv and. olfset printing. When: used: for direct printing, the large cylinderv 2 carries type which prints directly: onto sheets passing between the cylinders, the. smaller cylinderj-in such case, acting as anrimpres'sion' cylinder. against which the paper is printed When used in oifsetlprinting; however, the small cylinder acts as a blanket, receiving; the ink: impressions from. a printing plate attached to a plate segment ofi-the large cylinder and printing directly respect to the printonto a sheet against a platen segment of the large cylin d'er. In: the present invention, we; are concerned: with: the

machine in its capacity as. an offset printing machine.

The sheets- B to be printed are stacked on a vertically movable table 3. The sheets are lifted'up one by one by a pivotal suction: head 4 of afeeder C and deposited upon a conveyor D? which discharges them onto: a small feed table 5 -(seeFi'g 33-) against stop fingers ('not shown) and between an" upper'pressure roller 6 and a plurality of lower feedroll'ers-7.v The table 5- is provided with; suitable spaced openings through which the lower rollers==project to engage. the'unders'ides'z of the sheets. 1

The upper pressure-roller. 6 is movabletoward and-into feeding relationxwiththe lower rollers for advancing the sheet to the printing; couplev and then' away from the lower rollers to permitia new sheet to be introduced'zbetween them; As best. shown in. Fig. 3B* ,,th'is movementis imparted to the pressure roller 6 by means'of. a camw8 on the shaft 2aoperating through a-pivotal lever 9, an angle bar 10 rotatablysupported by end' stub'shafts 10a in" the side frames A, the lever 9- being connected at its: lower end to the angle ban-andan arm 11, yieldablyattached to the angle bar, which carries the pressure roller. At the proper. time lIT- the machinecycle, the cam-controlledipressure roller 6 engages the upper surface of the. sheet for feeding, and: more orless simultaneously the; stop fingers are lowered; out of the path of travel ofthe sheet. In this manner the. leading zedge. of the sheet is fed smoothly to pump (not shown). .be interrupted at the proper time in the machine cycle individually to the conveyor D. Two distinct motions are imparted to'the suction head, the one a vertical up and down movement to permit it to pick up the sheet from the pile, and the other a pivotal movement to permit it to translate the sheet to the conveyor D and then return to pick up the next sheet. The suction head is pivotally and eccentrically supported between a pair of pivotal arms 13 on the supporting frame E of the feeder, and up and down movement of the head is achieved by means of a reciprocating pivotal lever 14 (see Fig. 4A) having a cam surface 14a formed onits upper edge, a lever 15 pivotally mounted at 15a and carrying a roller 15b which engages the cam surface 14a, and a vertical rod 16 pivotally connecting the free end of the lever 15 with the arm 13. During each cycle of the lever 14 the suction head is raised and lowered. A tensionspring 17 assists the return down movement of the rod 16 and keeps the roller 15b in contact with the cam surface.

The upper end of the suction headis attached to a flexible tube 18, and, as best shown in Fig. 4C, the lower end of the flexible tube18 is connected to a housing 19. Atube 20,*in turn, connects the housing 19 to a suction It is evident that the suction must to release the sheet to the conveyor D. Accordingly, the housing 19 is provided with a pivotal lid 21 which is normally maintained closed by its own weight when suction is desired, however, when the suction is to be cut off, thelid is raised bya small .lever22 operated by the lever 14 and connected to the lower end thereof by a link 23. The relation between the present invention and the sheet feeding mechanism .will be discussed in detail below.

When the machine is used in offset printing, the printing plate is first dampened and then inked. As best shown in Fig. 1, the dampening fluid is applied to the plate by a dampening unit, generally designated by the reference character I, and the ink by the inking unit K. The inking unit comprises a plurality'of rollers interposed between the ink fountain and the plate. Certain of the rollers serve to break-up and distribute the ink, ultimately supplying it to a roller 25 (see Fig. 3A) which in turn supplies the ink to a pair'of form rollers 26.

Referring especially to Fig. 3A, each of the form rollers 26 is mounted between a pair of links 27, and twosuch links are pivotally mounted at each end of the shaft 28 which supports the roller 25. The links are pivotally adjustable by set screws 29 bearing againstcarns 30 to control the position of the form rollers 26 relative to the plate or surface to be inked. The earns 30 are positioned at either end of a shaft 31, which shaft is adapted to be turned by a handle to move the form rollers 26 out of contact with the surface that they would otherwise ink. Moreover, each form roller 26 is provided with a lift-olf roller (not shown), which is cam-controlled to lift the form rollers away from the platen surface during each cycle of the machine, since, of course, the platen surface is not to be inked.

A further standard feature of the machine is the automatic cylinder throwout, that is, the means for separating the printing couple in the absence of a sheet to prevent the will drop into the s.ot if no sheet is encountered, but will be supported by the sheet if one is present. If no sheet is encountered and the feeler drops into the slot, it will upon its movement in the direction of the moving sheet engage and actuate an arm 36, mounted on the shaft 37, in a counterclockwise direction to the position indicated by the broken lines in Fig. 3B. The shaft 37 carries a pin 38 thereon, and the pin is connected to a latch arm 40 by means of a tension spring 39. When the shaft 37 is actuated by the feeler 35, tension is put on the spring 39 to urge the latch arm 40 downwardly. The latch arm 40 is loosely mounted on the shaft 37 and is permitted only a limited downward pivotal movement thereon.

The feeler 35 must be driven in synchronism with the press, and with such timing with respect thereto that the feeler will be reciprocated forwardly in the direction of sheet movement while a sheet, if properly fed, is present over the slot in the table 5. To this end the pivotal member 34 supporting the feeler is actuated by the cam 8, and it has been found most convenient to connect it to the lever 9 by a link 42.

The instant when the feeler detects the absence of a sheet is not the proper time for a separation of the cylinders, since at this instant the cylinders may still be printing the preceding sheet. Separation at the time of detection is prevented by the pressure of the shoulder 43 of a disk 44 against the latch arm 40. The disk 44 is mounted at the end of the stub shaft 1b, and the pressure results from the tension of a heavy spring 45 acting on the disk 44. The spring 45 is anchored to a pin 41 in the frame A of the machine.

Just before the proper instant for a throwout movement, a cam 46 on the shaft 202 acts against a cam roller 47, thereby pivoting a lever 48 in a counterclockwise direction. The lower end of the lever 48 engages the latch disk 44 and relieves the pressure of the latch shoulder 43 on the arm 40. Thus, if the throwout shaft 37 had been actuated as the result of the absence of a sheet, the spring 39 will now be free to draw the latch arm 40 downwardly out of its shoulder engaging position. Of course, if a sheet is present, the arm 40 will remain in raised latch engaging position, even though the pressure of the latch has been momentarily relieved. A light tension spring 5t acts on the lever 48 to maintain the lower free end thereof in contact with the disk 44 and to prevent chattering. Upon the further rotation of the cam 46, the lever 48 will be restored to its clockwise position by a spring urged lever 57, one of the elements of the present invention, the function of which will be described below, thus permitting the heavier spring 45 to rotate the eccentric shaft lb in a counterclockwise direction to efiect the separation of the lower cylinder 1 away from the upper cylinder 2. The timed return stroke of the feeler 35 in a direction opposite to that of feeding permits a spring (not shown) to rotate the shaft 37 in a clockwise direction, thus releasing the tension of the spring 39 from the latch arm 40. In fact, the pin 38 bears directly against the latch arm 40, urging the restoration of the arm to latch engaging position, but the restoration can not take place until the disk 44 and the shoulder 43 thereof is reset. When, however, the lever 48 is again operated by the cam 46, the disk 44 is rotated in a clockwise direction to a position where the arm can reengage the shoulder 43 of the disk. The printing couple is thus restored to normal printing relationship. If, however, a subsequent sheet is missing, the arm 40 will not be permitted to reengage the shoulder 43, and the printing couple will remain separated. r

The machine as thus far described is the standard commercial Model 221 with feeder attachment sold by the Davidson Corporation, of Brooklyn, New York, and, consequently forms no part of the present invention, except as otherwise stated and in the manner in which the above described parts cooperate with the present invention. For a more complete understanding of the machine, although it: is not deemed necessary for an under'standingrof the present invention, reference may be had toithe aforementioned-patent.

Turning now to the present invention, as previously explained in the offset process; it is.-desirable and necessary to first apply'dampingsolution totheprinting plate in order that" the non-printingareas" willwrepel' the ink. Normally the ink rollers 26: are. lifted away from the printing cylinder 2*for this purpose forv a certainwnumber of machine cycles. This is accomplished by manually rotatingthe; shaft-'31; Thecamsilll'thereon bear against the screws 29 and: swing the ink rollers 26 away from the cylinder 25 The: machine-can then be? run for a certain number of dampening revolutions,- which are either counted or approximated by theoperator, before dropping'the ink rollers into operative contact with the printing plate. The sheet feed-ingcan then be initiated by the operator. In the, present invention these operations are performed automatically. In addition, when the ink rollers'are lowered the feeding; of sheets is initiated, the desired number printed, and finally', the machine shut off, all automatically.

According to the present invention, the closing of an operating switch 51 (see Fig. energizes'a solenoid 52 (see Figs. 1, 2A and 3A). The solenoid 52 is adapted to perform two functions: theone, to lock the'ink rollers-26 out of operative contact with the cylinder 2, and-the'other, toengage a clutch mechanism 53 of a counting device.

The operation of the solenoid 52 (see Fig. 3A) causes a horizontally disposedpawl 54 to engage the upper latch end of a vertically disposedperiodically reciprocating arm 55; The arm 55 is attached to the shaft 31, and when the arm is thus engaged by the pawl 54, the cams 30 on the shaft 31 are in position to -maintain the ink rollers 26 suspended away from the-periphery of the cylinder 2. When the'solenoid 52' is not-energized, the armature 52a thereof is in the lowermost position, and the operative end of. the pawl 54' v is in raised non-engaging position in relation to the arm 55. The pawl 54'is provided with an angle bracket 54ahaving a hole therein through whichthe armature 52a passes. The armature isprovided with collar nuts 52c which restupon the bracket when the solenoid is not energized. A- small tension spring 52b isiconn'ected between the bracket 54a and a collar 52d on the movable armature. When thearmature lSfilIl' the lowermost position, the tensionexerted by the spring 52b is-negligible; however, when the solenoid 52 isenerg'ized, the armature and the collar-nuts 52d thereon are raised and the; tension of the spring increased; so that the pawl 54' will engage the'lat'chend of the-arm-SS during the next reciprocating movement of the latter. Thus, the energization causes the'ink rollers 26' to" be locked out upon the next following reciprocation" of the arms55.

As'best shown in Fig; l, the reciprocation Of'the arm'SS is accomplished through a linkage arrangement consisting: of a horizontal-link 56; and a vertical lever 57. The link 5.6 is pivotally, c'onnected'atone end to the lower end of'the arm 55 andat the other end to the lever 57. The lower end of thelever 57 carries a roller'57a which is positioned closely to the roller 47 of the lever i8, so that each time the lever 48' isa'ctuat'ed from the, cam 46, the arm 55- willbe actuated. When notbeing actuated the arm 55' is maintained in a clockwise position'by a heavy tension spring 59, ho'wever,as we1have' already seen,

when the solenoid SZis energized; the pawl 5'4-'-is'" adapted to engage the upper end of the" arm 55 as soon as' the latter is again actuated from'the cam 46.

It is evident that once the ink rollers 26 are locked in inoperative position by the energization of the solenoid 52, they remain so locked until the'solenoid is deenergized, in which latter case the-pawl 54'is operated to the raised or non-engaging position and-the ink rollerslowered into their-usual operative contact with the cylinder 2: The

- release of the pawl" 54* occurs; if the solenoid'52ris not energized,. during the actuation of the arm 55- due: to the factv that the friction of the-arm- 55,- againsti the pawl 54'caused by the spring- 59 prevents premature release:

As best shown in Figs; 2A to 2D, theoperationof the solenoid 52 a'lso'causestheengagement of a pinclutch 53 of a control device. The control ,deviceis supported on-a small-platform-60 mounted-to-one of the side frames A; The control device isprovidedwith adial or scale 61 and an adjustable pointer 62 which maybe set for the desired number of preliminary dampening revolutions, after which the feeding of sheetsis-automatically initiated. The'function ofthe control device isto count-the number of preliminary dampening revolutions-and, when thepi'eset number is reached, to'open'a switch which starts the feedingof sheets and, also, deenergizes the-solenoid--.52-to bring the ink rollers into operation.

The closing of the pinclutch 53 by the solenoidz52 is effected by a vertical yoke 63' (see:Fig.- 20) attached to a rock shaft 64, which rock shaft is connected to; the armature 52a of the solenoid bymeans'ofaa horizontal link 65. The pins 53a of the'drivingand:driven:c1utch members, 53b and 530, respectively, are oppositely disposed and arranged in circular fashion atspacedt variable intervals to afford a minimum of slippage up'onengagement. The driven member 530 is keyed toa" driven shaft 66 and normally urged todisengaged position on the shaft by an internal compression spring 67 within the driven member. Thedriving member 53b isl'oca-ted ona shaft 68" which is' driven by reducing gears! from the shaft 2a, so that each complete revolution. of the shaft- 2a produces only a small increment of rotation of the shaft 63. A windspring 69 returns the shaft 66. to a fixed start positionwhen the clutch is disengaged. I

The dial 61' and-pointer 62 are mounted-on the outside of, a casing 70, and a micro-switch 71--is mounted'within the casing (see Fig. 2B). The end of the shaft 66 is provided with a pawl 73, rotatable with the shaft, and the pointer-62- is provided with ap'awl-72, oppositelyr disposed inrelation to 1 the pawl 73 and adapted to act as a fixed stop for the latter for purposesof setting. Thus, for example, withthe clutch-53' disengaged,-.the'pointer 62 can be set'relativeto the dial-6 1- forv a-.given number ofpreliminary dampening revolutions;- and, as the pawl 72 is rotated by theisetting of the. pointer the pawl; 73, urged by the spring 69 will i follow, rotating the A shaft- 66 through a-.corresponding arc and-thereby se-ttingathe pawl 73: relative to the contact; arm- 71a of the switch 71. Thereafter, when the clutch 53* has been engaged; the number; of preliminary dampening revolutions will be counted in terms-of rotation of theshaft 66 and the pawl 73, so that when the desired numberof preliminaryrevolu-tions has been reached, the pawl 7-3 will have been driven, against the opposing forceof' the spring- 69; into engagement withithe contact arm- 71w to open. the switch 71;- Once opened,' the switch 71- remains openuntil manually closed by; the push-button 'i'l'b' thereof. When the switch 71 is opened in the manner described, the circuit to the solenoid 52' is broken and the solenoidis deenergized, permitting the ink rollers to Y be lowered into inking contact with the plate. As-we shall also see, the openingof the switch x 71 also initiates thefeeding. of sheets ,to the printing-couple.

When the operating switch51 is CIOSCdyiHTaddl-tiOH to energizing the solenoid 52, it energizes a solenoid- (see Figs. 4A and 43, especially) which renders the sheet feeding mechanisminoperative by maintaining the lid 21 in raised position, andthereby destroying the suction to the sheet lifting head 4. When the pre-setnumber of. preliminary dampening revolutions has been reached and the switch 71opened, in the manner above described, the solenoid 80' isdeenergized, releasing. the lid 21 to establish feeding suction" to thesheetlifting head 4. Thereafter; the sheets are'fed one 'byrone' in" the usualrman'ner;

As previously stated, the present automatic controls '7 function to shut off the power and to render the machine and the feeding mechanism inoperative when the desired number of sheets has been printed. Accordingly, before closing the operating switch 51 to begin the automatic operation, a counting mechanism 83 (see Figs. 1 and 3B) is pre-set by means of the handle 83a thereof. Any suitable predet'ermining counting mechanism can be employed, but the one shown and described is of the type known and sold under the trademark Veeder-Root, manufactured by Veeder-Root Inc., Hartford, Connecticut. The predetermining counting mechanism has two dials; the one is set to the absolute number of sheets which are to be printed, and the other which registers the number of sheets actually printed, is pre-set to zero before each run. When the desired number of sheets has been printed, the counting mechanism closes a switch 85 (see Fig. 5) associated therewith, thereby cutting the power to the press and feed

motors

86, 87, respectively (see Fig. 5) and energizing the

solenoid

52 and 80 to render the machine inoperative.

The counting mechanism 83 is attached to the machine frame A (see Fig. l), and each sheet that is printed is registered thereon by means of the pivotal actuation of a horizontal angle bar 88 acting on the counting arm 89 (see Fig. 3C) of the counter. The bar is normally supported in raised position by a cam 90 on the shaft 2a, but once during each revolution, a depression in the cam permits a tension spring 88a to lower the bar 88 to the position indicated by the broken lines in Fig. 3B, thereby registering a printing revolution n the counter.

Of course, when a sheet is not fed to the printing couple during any cycle, that cycle should not be registered in the counting mechanism. During such cycles the angle bar 88 is adapted to be held out of operation by a vertical member 99 attached at its lower end to the latch arm 40. It will be remembered that if the feeler 35 fails to detect a sheet of paper, the latch arm 40 is adapted to be pivoted in a counterclockwise direction, but that normally when a sheet is detected it remains in the usual latch engaging position. The movement of the arm 40 is, therefore, utilized to determine whether or not the angle bar 88 will be actuated. When the arm 40 ispositioned in the latch engaging position, the upper end of the member 99 is aligned with a notch 88b formed in the horizontal portion of the angle bar, but when the arm 40 is pivoted as the result of a missing sheet, the member 99 is shifted to the position indicated by the broken lines in Fig. 3B (and by the solid lines in Fig. 1) to engage the horizontal portion of the angle bar and thereby prevent the descending counting stroke of the bar.

When the desired number of sheets has been printed and the power cut-off switch 85 of the counting mechanism has been closed, the press and feed

motors

86, 87 are stopped and the

solenoids

52 and 80 are again energized, the former to etfect the raising of the ink rollers and the latter to stop the sheet feeding. Since the operation of the solenoid 52 does not actually raise the ink rollers, but merely maintains them in raised position, the machine is so designed that in the event the cut-off switch operates while the ink rollers are in contact with the printing plate, the inertia of the system will continue the cylinder 2 to rotate until after the ink rollers will have been raised in the manner above described by the cam 46.

The operation of the present invention can best be understood, and at the same time summarized, by reference to the circuit diagram of Fig. 5. The operator will first make the various required settings, i. e., adjusting the pointer 62 (Fig. 2A) for the required number of preliminary dampening revolutions and the two necessary settings on the counting mechanism 83, the one accordirig to the number of sheets which are to be printed, and the other, the actualsheet counter, to zero. In lieu of numbered markings, the dial or scale 61 may be marked according to thedifferent types of plates which may be used. After assuring that there are enough blank sheets stacked in the sheet feeder, that the push button 71b has been operated to close the switch 7 1, and that the

main switches

100 and 101 of the press and feed

motors

86 and 87, respectively, are closed to ready them for subsequent operation, the machine is conditioned for automatic operation by the closing of the operating switch 51. The A. C. voltage supply is thereby imposed across the primary of a step-down transformer T, energizing the solenoids 52 and in the secondary of the transformer. As already described, the energization of the solenoid 52 holds the ink rollers suspended out of operation, and the energization of the solenoid 80 renders the sheet feeder C inoperative.

The operator may now close the push-button controlled start switch 102, the last manual operation required of him. The closing of the switch 102 completes a circuit to the pull-in coil 103 of an electrically-operated, mechanically-latched, electrically-released type multiple switch unit, generally designated by the reference character M. The pull-in coil 103 raises an armature 104 in position to be locked at the upper end thereof by a spring urged latch 108. The switch 102, of course, need only be closed long enough to permit the coil 103 to perform its function. The armature 104 is provided with three

contact arms

105, 106 and 107. In the normal lower inoperative position, thearm 105 closes contacts 105a and 105b, and the arms 106and 107 are open in relation to their respective contacts, whereas when the armature is locked in the raised operative position, the arm 106 closes the contacts 106a, 106b, the arm 107 closes contacts 107a, 107b, and the arm 105 opens contacts 105a, 105k. The switch 71 is in parallel with the contacts 105a, 105b, so that the

solenoids

52, 80 will be energized when the operating switch 51 is closed, without regard to whether the push button 71b has been first operated, however, the push button 71b must be operated before the start switch 102 is closed so that the

solenoids

52, 80 will continue to be energized by the flow of current through the switch 71 even after the start switch has been operated and the contacts 105a, 1051) thereby opened.

The closing of the contacts 106a, 106b as the result of operating the start button conditions the release coil 109 of the multiple switch unit M for subsequent operation, and the closing of the contacts 107a, 107b closes a circuit in the primary of the transformer T to the press and feed

motors

86, 87. The printing cylinders and the sheet feeding mechanism thus begin to operate, however, the actual feeding of sheets is prevented while the solenoid 80 is energized.

The printing cylinders 1, 2, continue to rotate with the inking rollers suspended out of operation and the dampening rollers in operative position for the number of preliminary revolutions for which the pointer 62 has been set, and at the completion thereof, the switch 71 is opened by the pawl 73 and the

solenoids

52, 80 deenergized. The deenergization of the solenoid 52 effects the release of the pawl 54 to unlock the ink rollers and, also, eifects the disengagement of the pin clutch 53 to permit the pawl 73 to be spring returned to the setting of the stop pawl 72. The deenergization of the solenoid 80 releases the lid 21 and establishes suction to the feeding attachment C, thereby initiating the feeding of sheets.

The printing of sheets continues in the usual way until the desired number pre-set on the counting mechanism has been reached, at which time the switch associated with the counter is closed, energizing the release coil 109 to release the latch 108 and permit the armature 104 to return to the lower position. The opening of the contacts 107a and 10712 stops the

motors

86, 87; the opening of the contacts 106a and 10Gb breaks the circuit to the release coil 109; and the closing of the contacts a and 105b again energizes the

solenoids

52 and 80, the former again locking up the ink rollers and the latter s eamers;

preventing any further feeding of sheets. The machine is thus rendered completely inoperative at the endfiofthe printing operation.

A=push button controlled stop switch 110 is'in parallel with the switch 85 so that the operator can-manually stop'the machine at any time before the desired number of sheets has been printed. This .switch, like the start switch 102, need only; be pressed momentarily to give the release coil time enough to perform-its function.

The invention has been shown and described in preferred form and by way of example, and obviously many changes and variations may be made therein which are still comprised within its spirit. It is to be understood, therefore, that the invention is-not-to be limited to any particular form or embodiment except insofar as such limitations are specified in the claims.

The invention-having been described, the following claims are made:

1. In a printing machine, the combination of a pair of printing cylinders, a printing plate carriedby one of the cylinders, driving means for rotating the cylinders, inking and dampening rollers for said printing plate, said inking-rollers being movable into and out of contact with said printing plate, and an automatic control unit for the printing machine comprising a control device for setting the machine for a selected number of preliminary dampening revolutions, means for locking the inking rollers out of contact with the printing plate duringthe preliminary dampening revolutions, a movable member, means for moving said member a fixed proportionate distance for each revolution of the cylinders, and means responsiveto a predetermined movementof said--movable member to release the inking rollers for contact with the printing plate.

2. A combination according to claiml including sheet feeding means, means for rendering the sheet feeding means inoperative during the preliminary dampening revolutions, an-d'means controlled by' the automatic control unit for initiating the feeding of sheets atthe completion of the preliminary dampening revolutions;

3. A combination according to-clairn 2 including a predetermining counter settable to the number of sheets to be printed, and means controlled by said counter for rendering the printing machine inoperative.

4. A combination according to claim 3 including cylinder separating means operable when a sheet is not fed during a machine cycle, and means controlled by the cylinder separating means for preventing the sheet counting means from operating.

5. A combination according to claim 3 characterized in that, after the desired number of sheets have been printed, the counter operates an electrical switch which breaks the current to the machine drive means, renders the locking means for the ink rollers operative and renders the sheet feeding means inoperative.

6. In a printing machine, the combination of a pair of printing cylinders, a printing plate carried by one of the cylinders, driving means for rotating the cylinders, inking and dampening rollers for said printing plate, said inking rollers being movable into and out of contact with said printing plate, a suction sheet feeder having a suction head, means whereby the suction to the suction head can be interrupted and restored, driving. means for operating the sheet feeder, and automatic controls for the printing machine comprising a control device for setting the machine for a selected number of preliminary dampening revolutions, means for locking the inking rollers out of contact with the printing plate during the preliminary dampening revolutions, means for interrupting the suction to the suction head of the sheet feeder during the preliminary dampening revolutions, a member movable a fixed proportionate distance for each revolution of the machine, and means responsive to a predetermined movement of said movable member to re- 10 leasei-the ink rollers for contactwith the printing plate and to: restorethe. suction to the suction headof the sheet-feeder whereby sheetswill be printed at the conclusion -of the preliminary dampening revolutions.

7. A combination according to claim 6 including a control'counting device adapted to be preset to thenumber of sheets to be-printed, and means controlled by the control counting device for interrupting the suction to the feeder and for stopping the driving means for the cylinders and-the sheet feeder when the desired number of sheets has been printed.

8, In an offset printingmachine, the combination of a pair of rotary printing cylinders, one of'said cylinders carryinga printing'plate; drive means for said cylinders, inking and dampening rollers, said inking rollers being movable into'and out of inking contact withthe printing plate, locking means including an electric solenoid for maintaining saidinking-rollers out of-cohtact-with the printing plate, and an automatic control'for regulating the number of machine cycles during which the inking rollers are locked'out of contact with theprinting plate, said unit comprising a rotatable shaft, an electricalswitch operable at acertain position of saidshaft tocontrol'the electric solenoid and thereby release the inking rollers for contact with the printing plate, means for setting said'shaft' relative to the switch for the selected number of machine cycles and power transmitting means from the cylinder drive means for rotating the pro-set shaft a fixed amount for each cycle of the machine, such that the electricalswitch will be operated at the completionof the selected'numberof machine cyclesfor which the ink rollers are locked-out of operation.

9. A combination according to claim" 8 characterized in-that the shaft is rotatable again'st'light spring pressureand that the power transmitting means to the shaft is automatically'disengaged and theshaft returned to the pre-set position after the selected number of machine cycles-for which the ink rollers-are locked out of operation.

10. A combination according to claim 8 including a pin clutch connection-between the rotatable shaft and the power transmitting: means, said clutchbeing automatically disengaged at the completion of the preliminary cycles during which the ink rollers are locked out of operation, and said clutch being disengageable to make possible the setting of the shaft.

11. In a printing machine, the combination of a pair of printing cylinders, one of said cylinders carrying a printing plate, a drive motor for the cylinders, inking and dampening rollers, said inking rollers being movable into and out of inking contact with the printing plate, locking means for maintaining said inking rollers out of contact with the printing plate, and automatic electrical controls for the printing machine comprising a solenoid for operating the ink roller locking means, an operating switch for initially energizing the solenoid, a power driven member settable to the number of preliminary dampening revolutions desired and incrementally adjusted during each machine cycle, a start switch to complete a circuit to the drive motor, and a switch operable by said power driven member at the completion of the preliminary dampening revolutions to break the circuit to the solenoid, thereby releasing the ink rollers to make operative contact with the printing plate.

12. A combination according to claim 11 including a counter settable to the number of sheets to be printed, a switch automatically operable by said counter when the desired number of sheets has been printed, and an electrical circuit completed by said switch to break the circuit to the drive motor and to energize the solenoid.

13. A combination according to claim 12 including a manually operable stop switch to enable the operator to stop the drive motor and to effect the lock-up of the ink rollers.

14. In a printing machine, the combination of a pair of printing cylinders, one of the cylinders carrying a printing plate, drive means for the cylinders, inking and dampening rollers, said inking rollers being movable into and out of inking contact with the printing plate, lock- .ing means for maintaining said inking rollers out of contact with the printing plate, a suction sheet feeder, drive means for the sheet feeder, and automatic electrical controls for the printing machine including an operating switch, a pair of solenoids operable by the closing of the operating switch, one solenoid to effect the lock-up of the ink rollers, and the other to break the suction to the sheet feeder, a start switch to start the drive means for the cylinders and the feeder, a power driven member settable to the desired number of preliminary dampening revolutions and being incrementally adjusted during each revolution of the machine, and a switch operable by said power driven member to break the circuit to the solenoids when the preliminary dampening revolutions have been completed, thereby initiating the feeding of sheets to the printing couple and permitting the ink rollers to apply ink to the printing plate.

15. A combination according to claim 14 including a counter settable to the number of sheets to be printed, and a switch automatically operable by said counter when the sheets have been printed, said switch controlling electrical circuits to elfect the shutting-off of the driving means for the cylinders and the sheet feeder and to reenergize the solenoids to lock-up the ink rollers and break the suction to the sheet feeder.

16. In a printing machine, the combination of a printing plate, inking and dampening means to apply ink and dampening solution to the printing plate, means for moving said printing plate relative to said inking and dampening means, means to render the inking means inoperative, a control member, means to set said member to provide a predetermined number of preliminary dampening operations, means for moving said control member in increments one for each movement of the printing plate past the aforesaid inking and dampening means,

and means controlled by the cumulative movement of said control member for automatically rendering the inking means operative after the preliminary dampening operations.

17. A combination as set forth in claim 16 including sheet feeding means, means to render said sheet feeding means inoperative during the preliminary dampening operations, and means controlled by the cumulative move ment of the control member for rendering the sheet feeding means operative after the preliminary dampening operations.

' 18. A printing machine comprising power driving means, a rotatable driven printing cylinder adapted to carry a printing plate, inking and dampening rollers adapted to make contact with the printing plate, means for locking the inking rollers out of operative contact with the printing plate to permit preliminary dampening of the printing plate, a control member, means for driving said control member to provide incremental movement for each revolution of the printing cylinder, means for setting said control member in a pre-selected starting position, and means controlled by the cumulative movement of said control member corresponding to a plurality of revolutions of the printing cylinder for automatically releasing the locking means after the preliminary dampening operations.

19. A combination as set forth in claim 18 characterized in that the control member is capable of being preset for a specified number of preliminary dampening operations.

20. A combination as set forth in claim 18 including means for preventing the feeding of sheets during the preliminary dampening operations, and means controlled by the cumulative movement of said control member corresponding to a plurality of revolutions of the printing cylinder for initiating the feeding of sheets at the conclusion of the preliminary dampening operations.

References Cited in the file of this patent UNITED STATES PATENTS 715,916 White Dec. 16, 1902 1,774,762 Roesen Sept. 2, 1930 2,220,255 Marchev Nov. 5, 1940 2,301,214 Knowlton Nov. 10, 1942 2,397,053 Schneider Mar. 19, 1946