US2629300A - Sheet counting and tab inserting device - Google Patents

Description

Feb. 24, 1953 SMITH 2,629,300

SHEET COUNTING AND TAB INSERTING DEVICE Filed Feb. 16, 1945 3 Sheets-Sheet l Feb. 24, 1953 R. B. SMITH SHEET COUNTING AND TAB INSERTING DEVICE 3 Sheets-Sheet 2 Filed Feb. 16, 1949 Feb. 24, 1953 Filed Feb. 16. 1949 R. B. SMITH 2,629,300

SHEET COUNTING AND TAB INSERTING DEVICE 5 Sheets-Sheet 3 M, INVENTOR.

Patented Feb. 24, 1953 aczasoq SHEET COUNTING AND TAB INSERTING DEVICE.

Robertv B. Smith, Dayton, Ohio, assignor to The Reynolds & Reynolds Company, Dayton, Ohio,

a corpo a on, .31 Ohi pli n e u y 6 .9 9. Ser a o- 6 712,

6- C aims. 9 3) Th s. nvention reltes to aut m tic. ab. i serter and m re part cular y to mechanism fo use in combination with printing: presses and the ike or nse t ng; t bs at giv n p nts n the stack of paper issuing from: the printing press.

A. large n mb au in r in ev ce ha e been designed and used from time to. time with varying degrees of success. These. ab. inserters have o een. t o Prac ical. n they a e fa to pr per y ompensate for malfuncti s or o her pe iar ties o he prin ing. press. or have oth rw been unsa i iaetory'. Th p lem of. providing a. means. for; inserting tabs at predetermined intervals in a stacle ofsheets be;- ing printed is somewhat complicated bythe use of offset presses wh ch the press continues to o rat e en. thou h. sheets are r e t d at th guide for registration and by the further fact that. a number of printed sheets. are. in. the. grips. per bars andw-il1;be added to, the stack of prints ed sheets after the press. stops. printing any addie tional sheets. Some tab inser-ters. have used de-.- vices for counting; the. sheets actually delivered 011130 h stack; but. counters of this type are 1111'! satisfactory in that. they takev up. valuable space or; interfere with the. proper operation of the press. Some. of the. prior art tab inserters have been operated in response to. a. predetermined number of revolutions; of the. impression cylinder shaft or some other movable. part. of the press, but these are impractical unless they take into consideration various facts such as. the fact that the impression cylinder makesseveral revolutionsbefore the first printed sheet is delivered to the 1ayboy..

It is. an object ofthis. invention to. provide a tab, inserter mechanism which includes a counter capable of taking into consideration various factors such as the fact that the impression cylinder makes. a predetermined number ofrevolutions before the first sheet is delivered onto the layboy and the fact that there will be times when the impression cylinder will operate when sheets are being rejected at the guide for registration.

It is. another object of this invention to provide an automatic tab inserter which is simple and inexpensive and yet. reliable in operation.

Another object of this invention is to provide automatic tab inserting means. which does not interfere with the mechanism used in printing or stacking the sheets of paper or the like.

Another object of this invention is to provide a mechanism which may be installed on existing printing presses without the. need for making any change. in the printing press.

Another object of this invention is to D fQvide a simple arrangement for straightening the paper strip from which the tabs are cut as it unwinds from the roll.

Another object is to provide a tab inserting arrangement in which the outer end of a roll of paper i projected nt t s ac f aper d s h l t ere until e e sheets of aper We ht thetab down before itis severed from the roll.

Another object of this invention is to provide an arrangement whereby the same mechanism may be used for inserting tabs at various. predetermined intervals.

It is another object of this invention to provide a tab inserter which may be set to insert the tabs at various predetermined intervals depending upon the number of sheets of paper to be packaged or grouped together,

Qther objects and advantages reside in the construction of parts, the combination thereof and the mode of operation, as will become more apparent from the following description.

In the drawings:

Figure 1 is a perspective view showing the tab inserter attached to the side frame member of a printing press;

Figure 2 is a fragmentary elevational View showing the relationship of two of the control switches to the impression cylinder shaft and the blanket cylinder shaft;

Figure 3 is a side elevational view of the tab inserting mechanism with parts broken away;

Figure 4 is a plan view of the tab inserting mechanism;

Figure 5 is a fragmentary end elevational view of the tab inserting mechanism;

Figure 6 is a diagrammatic view showing the control circuit; and

Figure 7 is a fragmentary elevational view showing one of the switch operating mechanisms.

The tab inserting mechanism disclosed herein is especially adapted for use on standard offset presses of the type in which an impression cylinder continuously rotates and sheets of paper are normally fed continuously through the press but may be rejected for some reason or the other at the conventional guide for registration, in which case the pressure between the blanket and plate cylinders automatically cuts off and no sheets are printed until the guide for registration again begins to accept sheets which are fed in proper registration. The mechanism is also well suited for use in presses wherein the press automatically stops in the event of malfunction of the printing mechanism.

3 In offset presses the pressure between the blanket and plate cylinders cuts off when for any reason sheets are rejected and when this occurs, the journal for the blanket cylinder moves relative to the main frame of the printing press. Advantage is taken of this movement for controlling the operation of the sheet counter, as will be explained hereinafter.

The tab inserting mechanism is of the type in which the tabs are out from a strip of paper fed from a roll and in which an electronic control is provided for operating the mechanism which feeds the strip of paper and cuts the strip into tabs;

Referring now to Figure 1 of the drawings, reference numeral ill designates generally the tab inserting mechanism which is adapted to e secured to the side frame I2 of a printing press by means of an adjustable bracket arrangement 14. The bracket 14 is held in place by means of bolts l6 which pass through slots H3 in an angle bracket 28 which is directly secured to the frame l2. The lower end of the bracket I4 is provided with bolts 22 which fit within the slot 24 provided in the member 25 which supports the tab inserting mechanism. By virtue of the above described arrangement, it is possible to vertically adjust the tab inserting mechanism relative to the printing press frame and it is also possible to horizontally adjust the relationship of the tab inserter mechanism to the stack of sheets fed onto the lay-boy 30 by the printing press.

The tab insert ng mechanism comprises a main frame 32 on which there is rotatably supported a spool or roll of paper 34 which is freely rotatable about the stationary pivot pin 36 carried by the'support 32. A strip of paper 38 is fed from the roll 34 past the guide roller 40 which is arranged as best shown in Figure 3. As the paper leaves the guide roller 40, it passes between a pair of rollers 42 and 44 which help to take the bend out of the paper leaving the roll 34. As indicated in Figure 1 of the drawings, the paper 38 leaving the roll 34 is fed between the rollers 42 and 44 in such a manner as to reverse the natural curvature of the paper which would otherwise cause trouble as the end of the strip of paper is fed onto the stack of sheets.

The mechanism for feeding the paper from the roll consists of a rotary solenoid 50 which serves to oscillate the shaft 52 to which the arm 54 is secured. Rotary solenoids of this type are now well-known and need no further description other than to state that energization of the solenoid im arts rotary movement to the solenoid shaft 52. The upper end of the arm 54 is connected to a link 56 which in turn is pivotally connected to a paper feeding slide mechanism 58. Paper feeding slide mechanisms of this type are now well-known and need no further description other than to explain that as the solenoid B is energized and the arm 54 moves in the direction indicated by the arrow in Figure 3 of the drawings, the paper feeding slide mechanism 58 will grip the strip of paper and cause a predetermined length of paper to be fed between the conventional paper guide 56 which guides the paper toward the cutoff knife 52. The knife 62 is located at the very end of the projecting portion of the paper guide Ell so as to be close to the stack of papers on the lay-boy.

4 The pivoted arm 54 is biased into the position in which it is shown in Figure 3 by means of a spring 64. A dash-pot 66 is provided for retarding the rate of movement of the paper feeding mechanism so as to avoid backlash of the paper on the roll.

The arm 54 is adapted to move into engage ment with a control switch 68 which, as will be explained more fully hereinafter, serves to place a resistance 5! (see Figure 6) in circuit with the solenoid 50 after the solenoid has completed its forward or paper feeding stroke. The purpose of inserting a resistance in series with the solenoid after it has fed the paper is to eliminate needless flow of current through the solenoid after it has completed its work and before it is deenergized. Upon deenergization of the solenoid 50, the spring 64 serves to return the paper strip feed mechanism to the position in which it is shown in Figure 3 of the drawings.

The paper cutoff mechanism comprises the cutoff knife 62 which is mounted on a stationary pivot pin 10 carried by the main frame 32, as best shown in Figure 5. A rotary type of solenoid 12 is provided for oscillating the crank arm 14 which in turn is connected to the cutoff knife 62 by means of a link 16. A torsion spring 18 carried by the pivot pin 10 and a coil spring 19 are arranged to urge the cutoff knife 62 and the operating mechanism therefor into the position in which it is shown in Figure 5 of the drawings.

Upon energization of the solenoid 12, the free end of the cutoff knife 62 will be pulled down by the link 16 until the lower end of the link 16 strikes the switch which serves to insert a resistance 8| in series with the solenoid 12, so as to prevent unnecessary flow of current through the solenoid 12 after the cutting operation has been completed but before the circuit to the sole noid has been broken. Upon deenergization of the solenoid 72, the springs 18 and 19 will return the cutoff knife or blade 62 to the position in which it is shown in Figure 5 preparatory to re operation of the tab inserting mechanism.

The tab inserting mechanism just described may be controlled by means of either a mechanical or an electronic counter so long as the counter is capable of taking into consideration all of the factors affecting the delivery of printed sheets onto the lay-boy. Thus, it is essential that the counter be capable of operating the tab inserting mechanism in response to the actual delivery of a predetermined number of sheets onto the lay-boy. Consequently, it is desirable that the counting mechanism include means for counting the number of revolutions of the impression cylinder shaft, making proper compensation for operation of the impression cylinder shaft at such times when the press is operating but the sheets are rejected at the guide for regis-' tration. In a standard offset press the impression cylinder shaft operates continuously, as explained hereinabove, but there will be times when the sheets to be printed will be rejected at the guide for registration, in which cases rotation of the impression cylinder shaft is not truly indicative of the number of sheets being fed through the press.

For purposes of illustration we have shown an electronic counter system in whichan impulse is set up once for each revolution of the impression cylinder shaft and in which these impulses are fed into an electricalaccumulator which may be set to accumulate a predetermined number of impulses before the tab inserting mechanism is energized. The means i or setting up the impulses includes a switch H (seeliligures 2 and 6) which is operatedbya'cam :I It onthe-end of the impression cylinder shaft 143. Suitable delay means, which will be described khereinatter, is provided for compensating for the fact that the impression cylinder shaft willmakea predetermined number of revolutions at the beginning of the printing operation "before the first printed sheet is deliyered onto the lay-boy. The number of reyolu tions of the impression cylinder shaft required before a printed sheet is delivered onto the layboy varies in diiferent types of printing presses and for that reason the counting mechanism disclosed herein includes means .for adjusting the amount of delay so as to make the device :applicable to difierent types of :printing presses.

.Asuitable count selector arrangement has also been provided so :as to select the frequency at which the tabs are inserted. For purposes of illustrating the invention, there is shown a'count selector which may be set torinsert a tab after each .25 sheets or after various multiples of 25., whereas the device could be designed so as to insert sheets at'some other scheduled frequencies. The counting mechanism also includes a reset arrangement which makes it possible to reset the counter to zero after a given counting operation.

Referring now to Figure 6 of the drawings wherein .I have shown :a preferred embodiment of the circuit for use in the counting mechanism,

reference numeral I00 designates conventional 115 volt .A. C. power lines which supply electrical energy to the mechanism. master control switch :I02 is provided in the main power lines for turning on and off the apparatus. A pilot light I04, which is directly connected across the power lines 100; serves the purpose of giving an indication as to whether ornot the switch I02 has been closed. .A pair oi rectifiers I06 have been provided for rectifying the alternating current and for supplying direct current "to the direct current power lines designated by the reference characters I08 and I09. The power lines I08 and I09 have been shown in heavy lines for the purpose of distinguishing the main power lines from the other lines involved.

The counting mechanism includes a first cam operated switch 0 which is arranged adjacent the impression cylinder shaft H3 so as to be closed once for every revolution of the impression cylinder shaft. Reference numeral I I-2 designates a switch which is adapted to be closed in response to eccentricmovement of the blanket cylinder journal II5 (see Figure 2'). Thus, if

for any reason the printing press fails to print the switch I I4 for a given number of revolutions of the impression cylinder shaft so as to automatically compensate for sheets removed from j the stack being counted. Reference numeral H6 designates a switch which under certain circumstances can be used for manually energizing the tab inserter so as to insert a tab at a desired point in the stack. A unit count light H8 has been provided in the circuit in such a place that it will iflash once for each revolution of the impression cylinder shaft. The purpose of -this light "is to assist the press operator in determining how long to hold the noncount switch open so as to compensate for sheets removed by him from a :given stack.

The electronic counter comprises a series of rotatable wafer switches which "are designed to interpret the impulses which result irom the opening and closing of the switches II 0., 1 I2, I I4 and I Hi. Three of these wafer switches, which have been designated generally by the reference numerals I20, I22 and I24, are adapted to be operated by means of a rotary solenoid of the type :shown in Figure 7 and which will be described more fully hereinafter. These three switches make one complete revolution for each 10 fim'pulses transmitted to the solenoids which operate the respective switches. A fourth switch I26, which may be referred to as a delay counter switch, is designed so as to require 12 impulses for each revolution of the switch.

In :Figure 7 of the drawings there is shown somewhat diagrammatically the arrangement of the switch actuating mechanism used for actuating the switches I20, I22, I24 and I26. Since the operating mechanism for all four of these switches is basically the same, only the operator for the one switch I20 will be described. Reference numeral I21 designates a conventional rotary solenoid which is used for operating the oscillatable ratchet disc I2I a which in turnoperates a complementary rotatable ratchet disc I 2 I b so as to step the switch operating shaft d around one revolution for each ten electrical impulses received by the solenoid 'I2I. In other words, the arrangement of the switch contacts and the ratchet elements I2Ia and I2Ib is such that the rotatable contact wafers carried by the shaft I20d normally make one revolution for each ten revolutions of the impression cylinder shaft =I I3.

Upon deenergization of the solenoid I2I, the coil spring I2I c returns the ratchet element I:2la to its zero position whereby it is ready to reengage the ratchet element 12 I b to step it around another step. Since more power is required for actually rotating the wafer switches than is required to overcome the action of the spring I2-Ic, provision is made for reducing the flow of current through the solenoid I2I upon the completion of its switch operating stroke. This latter means comprises "a switch I20e which is adapted to be opened by means of a cam projection IZiI-d formed on the ratchet element 121a. Opening of the switch 120a places the resistance 207 in series with the solenoid I21 so as to reduce the flow of current through the solenoid I21 to an amount which is merely adequate to prevent the spring I2ic from returning the solenoid to its "zero position.

The various stationary contacts which are arranged to be engaged by the contact wafers have been designated by arrows, it being understood that each arrow designates a stationary contact which is adapted to make contact with any portion of the rotatable contact wafer having any part movable into contact with the arrow. In order to eliminate unnecessary Jprolixity, the construction of the wafer switches will not be described in greater detail as they are of standard construction and are now well-known to all those skilled in the art. The shape of the various wafers and the arrangement or the stationary contacts are those shown inthe drawings.

Each of the wafer switches I22, I22, I24 and I26 is adapted to be electrically operated in the same general manner. The switch operating solenoids I23, I25 and I2? are similarly provided with resistance inserting switches I226, I24e and I266 respectively which serve to insert resistances in series with the respective solenoids.

Suitable spark suppression condensers I20g,' I22g, l2 lg, I26g and I289 have been arranged as shown in circuit with a high resistance I50. Spark suppression means of this type are wellknown and need no further description.

The switch I20 may be conveniently referred to as the first cascade switch. The arrangement of the circuit and the design of this switch is such that essentially it will accumulate five impulses before transferring one impulse to the second cascade switch I22. Cascade switch I22 in turn accumulates five impulses before transmitting an impulse to the third cascade switch I24. Reference numeral I26 designates the delay counter Which operates to delay the transfer of impulses and consequently the insertion of the sheets during the time when the press first starts up and the time when it delivers its first sheet to the lay-boy, as will be explained more fully hereinafter. The normally stationary contact I28 may be manually shifted from one contact to another so as to be in engagement with any one of the numbered stationary terminals provided on the delay counter switch I26. The numbers adjacent the contacts represent the delay which each would provide. Thus, when the contact I23 is arranged to engage the stationary contact No. '7, as shown, there will be a delay of '7 between the time that the cam switch I I first starts operating and the time that the firs tab is inserted.

Another function of the delay counter switch I 25 is to delay the energization of the cutoff solenoid a predetermined number of impulses after the energization of the tab inserting operation. It will be noted that contact No. 11 of the delay counter switch I25 is connected to enertact the No. 7 contactor of the switch I26, it is obvious that there will be four sheets delivered to the lay-boy between the time a tab has been inserted and the time that the tabis cut on. However, if the contactor I28 were arranged to engage contact No. 5, there would be six sheets delivered to the lay-boy between the insertion of a tab and the cutting of the tab.

Reference numeral I generally designates a manually operable count selector switch of the wafer type which sets up the necessary circuits to adjust the tab inserting mechanism to insert a tab at the desired count intervals. The setting of the count selector, as shown, is such that a tab will be inserted for every sheets delivered to the lay-boy. By moving the count selector switch in the direction indicated by the arrow, it can be set to insert tabs at any one of the following intervals: 50, 100, 125, 250, 500, or 1,000. A manual reset switch'of the'waier type,

generally designated by the reference numeral I 42, has been provided for clearing the circuits and resetting them to the zero position at the beginning of a given printing job.

A brief description of the manner in which the system operates will now be given. When the printing press goes into operation, the impression cylinder shaft starts to rotate and serves to close the switch III] once for each revolution of the impression cylinder shaft. Closing of the switch IIO automatically connects the unit count lamp III} across the output of the rectifiers I05. Closing of the switch I I0 also connects the stationary contact I52 of the delay counter switch I 26 di rectl to the negative side of the power circuit, so that when the solenoid I2! is energized so as to move the contact wafer I26a one step, the wafer I2Iia will be connected to the negative side of the line and will remain thus connected during the eleven succeeding impulses received by the solenoid I2'I. Closing of the cam switch III) also connects the nonprint switch I I2 to the negative side of the circuit. Just as soon as the sheets to be printed reach the guide for registration, the blanket cylinder will move toward the plate cylinder in accordance with standard practice in ofiset printing presses, and as the blanket cylinder thus moves, the nonprint switch II2 will be moved into the closed position so as to connect the solenoid iii of the first cascade switch I20 into the circuit. The noncount switch H4 normally remains closed at all times except when the press operator manually opens the same so as to prevent impulses from reaching the solenoid I2I even though the cam switch H0 and the nonprint switch II2 indicate that sheets are being printed.

Assuming that the switches I I2 and I I4 remain closed, the solenoid I2I will be energized every time the cam switch III? is closed in response to rotation of the impression cylinder shaft I I3. In referring to Figure 6 of the drawings, the reason for this is very apparent, since the one terminal of the solenoid I2I is always connected to the positive side of the power line I08 by means of the conductor I50 and the other terminal of the solenoid I2! is connected to the negative side of the circuit through the switch I20e, the conductor I62 and switches I I4, I I2 and I It. By tracing the various other circuits shown in Figure 6, one would find that when the first impulse is set up by the closing of the cam switch III] (again assuming that switches H2 and H t are closed), the solenoids I2I, I23, I25 and I2! will be energized and that upon reopening of the switch I I0, the solenoids I23 and I25 will remain energized but solenoids I2! and I 2? become deenergized. The second impulse coming from the switch IIO causes the circuits to the solenoids I2I, I25 and I2! to be closed and the circuit to the solenoid I23 to be opened. Reopening the switch IIO leaves all of the solenoids, With the exception of the solenoid I25, deenergized. Upon the third closing of the switch II 0, the solenoids I2I and I25 are energized. The solenoid I25 then remains energized until the sixth time that the switch I I0 closes. When the switch I I0 opens after the sixth impulse, the solenoid I23 remains energized until the seventh impulse, at which time the solenoid I23 becomes deenergized. After the eleventh impulse, the delay counter switch quits operating until the twenty-fourth impulse (assuming that the count selector is set to insert a tab at 25 sheet intervals). Twenty-five impulses after the first tab was inserted, the tab feeding solenoid 50 will be energized and four impulses thereafter (assuming that. the contact I28 is arranged to engage contact No. 7* of switch 126:) thetabcutofl mechanism will come into operation. Since the arrangement of the contacts and the contact actuating mechanism is clearly disclosed in Figure 6, and since anyone skilled in the art could con.- structa counter from the description given here.- inabove when taken in the light ofthe disclosure in the drawings, it is not necessary to go. into greater detail in describing or tracing the large multitude of circuit arrangements which result from the operation of the device.

. While the solenoids used for operating the wafer switches and the tab inserting mechanism are extensively known in. the industry as rotary solenoids and have thus been referred to herein, they-rotate through only a fraction of a complete revolution and then arereturned to the starting position by some means-such as the springslshown herein. Thus, the paper feeding. solenoid '0 tFigures 3 and 5) rotates through 90 and the cutoif solenoid 12 rotates through only-455 before being returned to starting position. The shafts of the rotary solenoids move axially a small amount when the solenoids are energized and it is this movement which causes the ratchets l2la and 12!?) shown in Figure 7 to engage one another. Since rotary solenoids of this type are now very well-known and are used extensively in the art and since the internal structure of the solenoids is not set forth in any of the claims, it is not believed necessary to further describe the solenoids.

While I have shown a tab inserting mechanism wherein the tabs are inserted at intervals which are multiples of 25, it is obvious that the mechanism could be adopted for counting in dozens or multiples of a dozen or in quantities such that a tab would be inserted every so many inches or feet. Likewise, the tab inserting mechanism could be used in paper mills where four or five rolls are sheeted at one time. In this latter case, by using the 125 count setting, it would be possible to sheet four rolls and have 4x125 or 500 sheets or one ream between the tabs. In a paper mill installation, the counter could be operated in" response to operation of the cutting bar or some other suitable part of the mill.

Although the preferred embodiment of the device has been described, it will be understood that within the purview of this invention various changes may be made in the form, details, proportion and arrangement of parts, the combination thereof and mode of operation, which generally stated consist in a device capable of carrying out the objects set forth, as disclosed and defined in the appended claims.

Having thus described my invention, I claim:

1. In combination with an offset printing press having an impression cylinder and a blanket cylinder; means for inserting tabs at predetermined intervals in the stack of printed sheets leaving the printing press comprising, means for supporting a roll of flexible strip material, counting means operated in response to rotation of said impression cylinder, tab feeding means for feeding the end of said flexible strip material onto the top of the stack of printed sheets, and means operated by said counting means in response to delivery of a predetermined number of printed sheets after each operation of said tab feeding means for severing the end portion of said flexible strip material, said counting means including a first switch means operative in response to rotation of said impression cylinder and a second switch means operative in response to sidewise 10 movement of said blanket cylinderfor modifying the operation of said counting means so as to compensate for failure of the printing press to print sheets while the impression cylinder is still operating.

2. In a printing press, means including a rotatingimpression cylinder for printing and stackingsheet material, sheet counting means including means operated by said impression cylinder' for counting the number of sheets passing over said impression cylinder, means operated by said counting-means for inserting tabs at predetermined intervals in said stack of sheet maserial, and manually operable means for momentaril'y rendering said counting means inoperable, said counting means including means for delaying the insertion of a tabat the beginning of the printing operation so as to compensate for the delay between the time the'flrst sheet passes over the impression cylinder and the time that the sheet is delivered to the stack.

3; In a machine of the character described, continuously operable means for feeding, printing and: stacking sheet material, means for supporting a roll of flexible strip material, counting means operable by said sheet feeding means for counting the number of sheets fed onto said stack, first means operated by said sheet counting means at given count intervals for projecting the end of said flexible strip material onto the stack of said sheet material and second means operated by said counting means for severing marker tabs from the end of said flexible strip material, a signal light, means for momentarily energizing said signal light once for each sheet passing through said sheet feeding means, and manually operable means for rendering said counting means inoperable during a predetermined number of flashes of said light whereby said predetermined number of sheets may be removed from the stack without altering the number of sheets delivered to said stack between adjacent marker tabs.

4. In combination with a printing press having a continuously rotatable impression cylinder and a blanket cylinder which moves sideways when sheets are rejected at the guide for registration, means responsive to rotation of said impression cylinder for setting up electrical impulses, an electrical accumulator for accumulating impulses set up in response to rotation of said impression cylinder, and tab inserting means operated in response to the accumulation of a predetermined number of electrical impulses by said accumulator, said electrical accumulator comprising means for delaying the accumulation of impulses for a predetermined number of impulses at the beginning of the printing operation so as to allow the first sheet to be printed to pass through the press before the accumulation of impulses begins.

5. In combination with a printing press having a continuously rotatable impression cylinder and a blanket cylinder which moves sideways when sheets are rejected at the guide for registration, means responsive to rotation of said impression cylinder for setting up electrical impulses, an electrical accumulator for counting impulses set up in response to rotation of said impression cylinder, tab inserting means operated at predetermined counts in response to the accumulation of a predetermined number of electrical impulses by said accumulator, said electrical accumulator comprising means for delaying the accumulation of impulses for a predeter-mined number of impulses at the beginning of the counting operation, and means operated in response to sideways movement of said blanket cylinder in response to rejection of sheets at the guide for registration for rendering said electrical accumulator ineffective for accumulating impulses set up in response to rotation of said impression cylinder for a predetermined number of impulses corresponding to the number of sheets rejected at the guide for registration.

6. A tab inserter for use in inserting tabs in the stack of sheets delivered onto a lay-boy by a printing press comprising in combination, a main frame having a first portion adapted to be located at the side of the printing press and a second portion adapted to extend toward the sheets being fed onto the stack, means on one side of said first portion for supporting a roll of paper ribbon, a rotary solenoid located on the opposite side of said first portion, means for guiding paper from said roll along said second portion, means operated by said rotary solenoid for feeding paper .from said roll through said guide means, a cutoff knife mounted adjacent the end of said secend portion for cutting said paper ribbon into short tabs, a second solenoid for operating said cutoff knife, and means for counting the number of sheets delivered onto the lay-boy, said counting means including means for operating said first solenoid at a given count interval and for energizing said second named solenoid a predetermined count interval after the operation of said first named solenoid.

ROBERT B. SMITH.

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

UNITED STATES PATENTS Number Name 'Date 1,118,009 Huckins Nov. 24, 1914 1,119,861 Niles Dec. 8, 1914 1,770,973 Coy July 22, 1930 2,122,710 Bidwell July 5, 1938 2,346,869 Poole Apr. 18, 1944 2,382,998 Kleinschmidt Aug. 21, 1945

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