US2170488A - Method and device of feeding sheets to printing and other sheet working machines - Google Patents

Description

Aug. 22, 1939. G. SPIESS 2,170,488

METHOD AND DEVICE OF- FEEDING SHEETS TO PRINTING AND OTHER SHEET WORKING- MACHINES. 7

Filed Nov. -1s, 195s Patented Aug. 22, 1939 UNITED STATES PATENT OFFICE METHOD AND DEVICE OF FEEDING SHEETS TO PRINTING AND OTHER SHEET WORK- ING MACHINES Georg Spiess, Leipzig, Germany Application November 18, 1936, Serial No. 111,479 In Germany November 19, 1935 5 Claims.

.This invention relates to improvements in and relating to the registering of sheets during the feeding thereof to printing or other sheet working machines.

In printingpresses of all kinds the highest printing capacity combined with the smallest circumferential speed-and the smallest diameter of the cylinders is attainable if the sheets pass the machine in direct succession, that is to say without any intermediate space. In practice this is quite impossible on account of the arrangement of the sheet grippers in the cylinder, which necessitate a certain space or free channel angle. An interval in the succession of the sheets is, moreover, necessary in that in rhythmically working printing machines the sheets must be taken-off from a state of rest, it being thereby necessary to bring the sheets, fed from the pile to the machine, to a standstill and further to speed them up to the circumferential'speed of the cylinder. With the stopping of the sheet is associated its registration at the forward or front guides. The stopping of the sheet from its feeding speed combined with the front registration and the further acceleration requires a considerable period of time in relation to the total duration of a working cycle, which may be still further increased by a necessary side registration of the sheet following on the front reg-- -istration.

This loss of time takes place in the printing machine in the so-called free channel angle which is measured off from the cylinder during this loss of time and illustrates the extent to which cylinder circumference and diameter and the circumferential speed dependent thereon are of necessity increased with respect to the smallest value of these sizes possible if the sheets followed in uninterrupted succession.

With individual conveying or feeding of the sheets to a printing machine or similar sheet working machines, that is to say when the sheets follow one another in spaced relation, the feeding, front registration and side registration-require a peripheral segment or sector of the printing cylinder, namely the so-called free channel angle, which also remains uncovered in the case of the largest size of sheet capable of being worked. The above-mentioned operations, in or- 0 der that the diameter of the cylinder, which is their operation. If sheets of smaller size are worked on the machine then a correspondingly greater period of time is available for effecting the feeding, front and side registration, namely the period, within one revolution of the printing cylinder, which corresponds to the circumferential segment of the printing cylinder not covered by the sheet.

With underlapped conveying the feeding, front and side registration are independent of the channel angle as all of the operations can be effected whilst the previously fed and registered sheet is still being drawn off through the ma- 'chine. There is thus available, in any case, whether the sheet is large or small, a suflicient time period for the carrying out of the aforesaid operations as the front guides. return, immediately after freeing the previously registered sheet, into their working position and thus the conditions for the feeding and registering of the following sheet are again produced. However, disadvantages and difiiculties'are associated with the side registration of the sheet beneath a covering sheet. The same may be said for the lateral registration of the sheet during its feeding and acceleration by intermediate grippers which pass it to the cylinder. If, however, in order to overcome .the difficulties and disadvantages. of the above-mentioned type' of registration it is preferred to use the usual side registration by means of side registering devices which grip the sheet above and below, which registration can operate at the earliest when the rear edge of the sheet being drawn-offfrom the machine has passed the line of engagement of the side registering device, then the side registration of the sheet is again limited to a very small time period if it is not desired correspondingly to increase the free channel angle necessary therefor and .with it the diameter of the printing cylinder. 0n the use of this usual lateral sheet registration there results, in spite of the underlapped feeding, the same circumstance as with the individual feeding of the sheets, namely that with the smaller size a larger time period is available for the sheet registration and therefore the sheet registration with the smaller sizes can be carried out more smoothly and more slowly.

This possibility has hitherto not been used with automatic sheet feeding; moreover with smaller sizes the step of the feeding, front and side registration is confined within the small period of time within a working cycle, which is determined by the diameter of the printing cylinder and the largest workablesize. The control of the front guides and the feeding device is in conformity with the working of the largest size coupled with the smallest sheet distance, without any adjustability of the control being provided so that the larger time periods or sheet distances available with the smaller size are made usable for a better and more smooth stopping and registration of the sheet.

The object this invention is to overcome the above disadvantages by the better use of the time available for the stopping and registration of the sheet in all cases in which sheets of smaller size than the largest size, for which the machines and feeder are constructed, are to be worked. 1

According to the invention, the control of the front guides and the sheet separating device as well as, if desired, the side registering device are made to conform by adjustment of the corresponding controlling means to the particular size of sheet to be worked and also with smaller sizes the feeding of the sheets to the front guides and the side registration is effected as quickly as pos sible following the drawing-off of the previous sheet. For this purpose there is only necessary an adjustment of the control of the front guides which can be arranged either on the machine or on the feeding device by means of an adjustable cam, and a corresponding adjustment in the drive of the sheet feeder, for example by an adjusting clutch so that the feeding operation can be initially displaced somewhat in point of time. If also more time is to be obtained for the side registration then also an adjustable control cam disc is also provided for the drive of the side registering device so that by the adjustment of the cam disc the side registration can be displaced initially in point of time.

If the larger sheet distances present on working with the smaller size and the time thereby made available is not to be taken advantage of for the improvement of the sheet registration, but the stopping and registration ofthe sheets is to be allowed to take place for example in the same short period of time as when working with the largest size of sheets, the initial displacement in point of time of the registering operation attainable by the adjustment of the control of the front guides, the side registering device and the feeder makes possible a larger printing capacity of the machine by increasing its working speed without an increase of the conveying speed of the sheets, above that provided for the conveying of the largest size of sheet, being necessary.

If the capacity of the machine with the smaller I I all parts of the printing machine and of the feeder not necessary for the understanding thereof being omitted.

Referring to the drawing:

I denotes the frame of the printing machine, 2 the frame of the feeder, 3 the upper'feed table with the front guides 4 formed as cover guides, which are secured. to a reciprocating shaft 5 carried above the feed table. The usual feed tapes for moving the sheets down the table 3 are indiis driven from the control shaft 2I cated at 3. On the reciprocating shaft 5 is arranged further an arm 6, the free end of which .is connected by a link bar I with one end of a crank lever 9 which is swingably mounted at 8. A two-part cam disc I la arranged on the shaft I I of a cylinder I2 of the printing machine acts against a bearing roller II] of the crank lever 9. One part I4 of the said cam disc is rotatably and. adjustably arranged on the shaft II and is arranged fixable in relation to the fixed part I3 of the disc IIa. by means ofa curved slot I5 and a clamping screw IS.

The shaft II of the cylinder I2 is driven from the main drive shaft 21, by means of a gear train 28, 29, 30, 3|, the last gear 3| being geared directly to the cylinder I2. The shaft I8 is driven from the main drive shaft 21 by the gear train 28, 29, 30, 3|, 32, 33 and a pair of bevel gears I1, the second of which is on the shaft i8. The shaft I8 drives the feeding device through a pair of bevel gears 34, one of which is on the shaft I8 and the other of which is on the control shaft 2| of the feeder. The main shaft I9 of the feeder thereof through a gear 35 carried by the latter and a gear 36 on the former.

In the shaft IB is arranged an adjusting coupling or clutch 20, which enables the operating period of' the feeder to be suitably adjusted in relation to the operating period of the printing machine.

By adjustment of the two-part cam disc or eccentric I3, I4 the point of time of the return of the front guides 4 into the receiving position can be varied as desired within a working cycle. Thus, on working with smaller sheets the time of return of the front guides can be initially dis placed. with respect to the adjustment for working with sheets of the largest size. In conformity thei ewith the sheet feed may be correspondingly initially displaced by the adjustment of the clutch or coupling 20.

At 26 is shown a side registering device, that is to say a sheet registering device of known construction and therefore not more fully described, which is'actuated from a cam disc 22, arranged on the control shaft 2I of the feeder, by means of a lever system 23, 24, 25. The cam disc 22 is formed in the same way as the cam disc or eccentric I3, I4 for controlling the front guides as a two-part adjustable cam disc, so that by its adjustment the operation of the lateral registration of the sheets can be controlled as desired within a working cycle.

The operation of the apparatus for various sized sheets is as follows:

Let us assume that in the drawing the apparatus has been adjusted for the largest sheet size, which covers the entire cylinder circumference to the utmost permissible point, leaving the smallest possible free channel angle. A short --time of space results, since the cylinder possesses a certain rotation speed, during which the new sheet must be prepared engaged by the cylinder. This period of time is determined by size of the cylinder section which has not been covered by the sheet, that is, by the additional period which the cylinder needs to run for a complete turn. This interval of time lasts from the moment that the rear edge of the sheet passes the front guides 4 until the cylinder grippers take the new sheet from the front guides 4.

Since only after the passing of the trailing edge of the sheet can the front guides 4 again swing inwardly, the straightening of this sheet on.'the guides l as well as the lateral arrangement must take place in the short space of time which elapses, until the cylinder grippers come into the position necessary for the taking of the sheets.

In .the past, nothing used to be changed on this arrangement of sheet feeding, straightening and intake, when a'shorter sheet size was used. That is, everything transpired at the same speed as if the larger sheet size were used. This, however, is not the case in my device, since the trailing edge of the sheet of smaller size passes the front guide 4 sooner than would the trailing edge of a larger sheet. This affords the possibility of bringing guides l to the straightening position, correspondingly sooner to let the new sheet advance sooner and to make the lateral adjustment sooner. That is the purpose of the invention, which, in order to accomplish this, regulates the return movement of guides l by means of the two-part cam discs ll, I4; and also, by means of coupling 20, times the process of the separating of sheets and the feeding action, and also, when necessary, times the process of the lateral adjustment, within one cycle of the operation by adjustment of the two-part cam 22.

I claim: 7

1. A method of feeding sheets to printing and other sheet working machines by means of mechanical sheet feeders, comprising simultaneously varying the working cycles of the front guides and the sheet feeding device in accordance with the size of sheet used.

2. In a sheet feeding device of the class described, including a mechanical sheet feeder, front guides for said sheets, side registering means for said sheets; a single means for driving both said front guides and said feeder, and separate means associated with said drive means for simultaneously varying the working cycle of said side registering means and also said feeder in accordance with the size of sheet used.

3. The structure of claim 2, and means associated with said drive means for varying the working cycle of said side registering means.

4. The structure of claim 2, said means for varying the cycle of said front guides comprising an adjustable cam disc, and said means for varying the cycle of said feeder comprising an adjustable clutch.

5. The structure of claim 2, means associated with said drive means for varying the working cycle of said side registering means, said last named means comprising an adjustable cam disc, said means for varying the cycle of said feeder comprising an adjustable clutch.

' GEORG SPIESS.

Images