US1952032A - Printing press - Google Patents

Description

March 20, 1934.

P. RAPPEPORT PRINTING PRESS Filed Nov. 9. 1932 3 Sheets-Sht 2 J'n uenfor:

March 20, 1934. P. RAPPEPORT 1,952,032

PRINTING PRESS Filed Nov. 9. 1932 3 Sheets-Sheet 3 -Fig. 'Z

Jnvenfor: I

Paul Rappeparl flttomey.

Patented Mar. 20, 1934 PRINTING PRESS Paul Rapneport, Vienna, Austria, assignor to firm Schnellpressenfabrik Koenig & Bauer Aktiengesellschaft Modling, Modling, Austria Application November 9, 1932. Serial No. 641,902 In Austria July 15, 1930 22 Claims.

There is known a hand printing press, the socalled Kiirpresse, in which the sheet to be printed is not taken by grippers on a cylinder but a printing form lying on a relatively thin metal base or bed, together with the printing sheet lying on it (and about to receive the impression) and together with a cover bearing the make-ready, are all moved frictionally by and between two channeled hard rollers there being no toothed bed and the upper press cylinder. The characteristic feature of this well known press is that the printing form together with the base, thesheet of paper and the cover are transported exclusively by the friction which is' produced by the pressure exerted from above and below by said hard rollers on the bed and the parts carried thereby. This kind of drive of the printing form has an advantage over all other printing presses in which the printing form carrier is driven either by hand or by a motor, in a positive manner, by a rack and pinions or the like and works together with an impression cylinder which is likewise driven in a positive manner.

In high speed stop cylinder presses the printingform-carrier, that is to say: the carriage or the bed-is driven by means of racks and pinions from the main drive. The impression cylinder of such machines is. driven from the bed by racks and pinions. The impression cylinder and the bed therefore have a compulsorily synchronous movement. As is well known, in these machines the printing form must be situated at a very exactly fixed height, and furthermore, the impression cylinder must have a very exactly fixed diameter, in-order that the impression form may have exactly the same speed as the circumference of the impression cylinder. If the diameter of the impression cylinder is only a little bit larger or smaller than as prescribed, the impression cylinder will receive a somewhat different circumferential speed from that which corresponds to the speed at which the printing form is compulsorily driven a by the bed. In such case the printing form does 5 not travel uniformly with the impression cylinder,

but it shifts somewhat in proportion to the latter. This shifting then leads to the wellknown smutting. The reason. for thisn ras already stated, that the printing form on the one hand is frictionally driven by the impression cylinder and on the other hand is positively driven by the bed. The printing form therefore receives a-double drive. The advantage of the above mentioned hand printing press is that the printing gearing (e. g., racks and pinions) connecting the form of the same does not receive a'double drive,-

but only one single drive. This drive consists only of the natural frictional drive caused by the pressing of the upper press cylinder upon the printing form which is rolled through between the upper and a lower press cylinder. A further compulsory drive of the printing form does not occur in'this press (Kiirpresse).

In presses of the kind mentioned above the sheet which is to be printed is fed between the cover bearing the make-ready and the surface of the printing form. Such feeding is however only possible at relatively low printing speeds, for the sheet must remain on the printing form not only while it is being printed, but also while the bed is travelling back again. It is therefore necessary when changing the sheet to stop the printing form for a short while or at least to slow down the speed so that the sheet may be replaced by another one without difficulty and without danger for the minding staff.

It is an object of the present invention to combine the above mentioned advantages of the Kiirpresse with the higher speed and the easier feeding attainable in the well known stop cylinder presses and thus to create a machine which is very much simplified as compared to any of the hitherto known types of stop cylinder presses.

To attain the same, I do not drive the type-bed, as is customary with stop cylinder presses, but the printing cylinder equipped with sheet holding s5 grippers and with covering is driven independently of the bed and directly from the main drive of the machine, the cylinder being arranged freely revolvable on its shaft and coupled only during the printing process with the gearwheels fastened on this shaft and meshing with thetype bed'racks.

The connection of the oscillatory printing cylinder shaft with the type bed through the two gears fastened to the shaft which gears engage racks on the type bed serves the purpose of moving the printing form only so long as is necessary to allow the impression cylinder and the counter pressure roller to take hold of the printing form, whereby the impression cylinder and the counter pressure roller now in turn take over the further movement of the printing form at exactly the same speed as that of the circumference of the impression cylinder. In order that the drive of the bed through the racks may be interrupted during this period of travel-the printing period proper the distance between successive teeth on both of the racks and the toothed wheels meshing with them on the cylinder shaft is made somewhat greater than 7.

otherwise necessitated by the pitch line of the gears, so that the teeth are spaced apart slightly, thus allowing sufiicient play between the teeth for the purpose stated.

It will be understood that the forward stroke of the bed, that is the printing stroke, consists of three sections: (1) A short distance, during which the two press cylinders have not yet seized the printing form; (2) The printing stroke proper, during which the two press cylinders propel the printing form, and (3) a short distance, after the two press cylinders have again released the printing form. The two type bed racks serve for the movement of the bed and the parts carried thereby only for the two outer sections of the three just mentioned and for the whole backward movement of the printing form, while the impression cylinder stands still. In order that the printing form, during the middle section of the three stroke sections ofits forward movement i. e., during the printing stroke proper, may not be positively driven by the two, racks, but exclusively bythe friction which is produced by the pressure from the two pressure cylinders, the racks have been arranged in a special manner as'above indicated.

The drawings show, by way of diagram, the construction of an example of the invention, viz:

Fig. 1, a vertical cnoss section through such a printing press,

Fig. 2, a side view of Fig. 1, from the right, the side frame being removed,

Fig. 3, a speed diagram of the printing cylinder,

Fig. 4, a special interlocking device for the coupling mechanism,

Fig. 5, an auxiliary coupling between the gripper movement cam and the printing cylinder,

Fig. 6, a modified construction of the stop pawl, including a brake for the impression cylinder,

Fig. 7, a plan view of the type bed, and Fig. 8, a cross-section (in front view) of the type bed. i

Between the two press cylinders 1 and 17, the top one of which (1) is equipped with sheet holding grippers and covering for the make-ready, if

travel of the such be desired, the printing form lying on a relatively thin base 16 is rolled through. Before being seized by cylinders 1 and 17, base -16lies on bars 23, 24 of the-chase-like type-bed, to the longitudinal sides of which are attached the two toothed racks 14, 15.

Thebase 16 rests loosely on the bars 23, 24. The two toothed racks 14, 15, are, by way of an example, firmly connected with the bars 23, 24. Inthe bars 23, 24 there are' seated pins 60, 65 which take along with them blocks 61, 66 slidably mounted in base 16, these blocks 61, 66 sliding in slots 62, 67 of the base 16. In the running' directionof blocks 61, 66 springs 63, 64 and 68, 69 are arranged on opposite sides of the blocks 61, 66 which springs tend to hold the blocks 61, 66 in their middle position. The base 16 with the printing form can therefore shift somewhat relatively to the two racks 14, 15, to obviate possible shifting of the form on the bed.

- On both lateral surfaces of base 16 there are indentations in which rest springs 73, 74 which press against the bars 23, 24. Consequently the base 16 can also shift somewhat in the cross direction relatively to the two racks 14, 15.

The driving of the two press cylinders 1 and 17 and of the printing form of the type bed respectively is eifected by way of the printing cyla stop 19.

inder shaft 2 to which are fastened the gear wheels 3 and 4 meshing with the type bed racks 14, 15 and on which the printing cylinder 1 is arranged, to turn loosely between the two gear wheels 3 and 4.

During the printing stroke of the type bed and consequently also of the printing form the impressiori cylinder 1 is coupled with one or with both gear wheels 3, 4, owing to the clutch pawls or detents 5, 6 which are mounted in the gear wheels 3, 4 and which are each under the pressure of, a spring such as 5a (Fig. 4), tending to cause them to engage corresponding indentations in the ends of the cylinder. When the printing stroke is finished and when so the cylinder has returned to its'original position (Fig. 2), cylinder shaft 2 and along with it also the two gear wheels 3, 4 fastened to it begin to turn backwards. To prevent the cylinder from taking part in this reverse movement, a pivoted pawl 20 is mounted on a fixed support, which pawl when the printing cylinder is at a standstill falls into place behind In order that the pawls may come out of the indentations in the ends of the cylinder when the gear wheels 3, 4 turn backwards, bevelled edges 33, 34 are provided in the direction of this backward movement on both the pawls 5, 6 and at the rear of each indentation whereby the pawls are forced outward against the pressure of their springs.

The catching in of the pawl 20 and of the clutch members 5, 6 takes place without causing any wear of any part; for both devices enter into operation while the gears 3, 4 are changing their direction, i. e. while they are at a standstill. 110

In order that the toothed racks 14, 15 may not affect the transport of the type form and that they may in no way act upon the type form during the printing period as long as the same is under the influence of rollers 1 and 17, the distance chosen between the gear wheels 3, 4 and the toothed racks 14, 15 is a little larger than requiredby the pitch line of the gears.

For driving the impression cylinder shaft 2 atoothed wheel 7 is fastened to it; which meshes with a toothed segment 8 oscillating about a stationary pivot 18. The toothed segment 8 receives an oscillating movement from a motor through 4 worm 13, worm wheel 12, crank shaft 11, crank 10 and sliding block 9, the latter of which slides in a radial slot of the segment. For the printing stroke the crank must pass through an are larger than 180 and during this period the block 9 slides in the upper part of the slot, whereas for the return stroke the movement of the crank is smaller than 180 and during this stroke of the segment the block slides in the ,lower part of the slot; the consequence is that the cylinder. shaft 2" and the parts driven by it will during the printing period advantageously be moved slower but with greater force than during the return movement for which the speed is greater, i. e. the unavoidable return-time is shorter and the energy which is transmitted at the teeth of the segment, is smaller accordingly. I

The spring-pressed pawls are preferably locked in place after being fixed into the indentation ofthe printing cylinder, thus avoiding accidental release of the impression cylinder after it has been clutched to the driving gears.

Towards ,the end of the printing. stroke, especially when operating at high speeds, the printing cylinder, in consequence of its relatively high moment of inertia, tends to'run ahead of its driving gears 3 and 4, which may cause the printprinting cylinder 1 is at a standstill the sliding pawl 5 (Fig. 4), which is situated in one of the two gears that also drive the type-bed and which are attached to the impression cylinder shaft, enters into the respective indentation of impression cylinder 1, thus initiating the drive of the cylinder in the direction of the arrow of said figure. At the same time the toothed wheels 3 and 4 move the type-bed from its end position at the rear towards the impression cylinder. The printing begins. Up to point B of the diagram the speed of the printing cylinder shaft is steadily accelerated, and therefore also that of the impression cylinder driven through clutch member 5. The forward fiat face 31 of the pawl 5 now contacts with corresponding flat face 32 of the indentation in the impression cylinder. At point B the accelerated movement of the driving mechanism and with it also that of the impression cylinder shaft changes into a progressively retarded motion and finally the shaft comes to rest at point C, which corresponds to the front return point of the bed. As the impression cylinder possesses a great inertia, it tends to maintain the speed which it has attained at point B except as diminished by the friction. If it should be left to itself, the speed of the impression cylinder would not follow the course of the curve BC, but that of the dotted line BD; i. e. the cylinder 1 would tend to advance in speed the coupling mechanism which is guided inthe gear wheel 3. As a result thereof the oblique face 33 of the clutch member 5 would ride against the corresponding oblique face 34 of the impression cylinder and, in its further course, would slide along the same, whereby it would lift the clutch pawl 5 out of itssocket and so the impression cylinder would be freed from the driving gears.

In order to avoid this a bolt 35 is provided at the opposite side of the coupling mechanism 5 which bolt is operated by a stop 36 fixed on the frame of the machine or elsewhere, said stop coacting with a lug 37 on the bolt. The bolt 35 is forced in one direction after every full forward revolution of the cylinder and in the contrary direction after every full backward revolution of the gear 3, shortly before the cylinder is brought to a standstill. The stop 36 thus effects in a safe way the unlocking as well as the locking of the pawl by the bolt.

As on the one hand the position of rest of the impression cylinder relative to the fixed stop 36 both after the forward rotation as well as after the backward revolution is always the same, and as on the other hand the-stop 36 and also the lug 3'7 have a certain thickness, it is necessary that the resiliently supported lug 37 be displaceable relatively to the bolt 35 by the com bined thickness of stop 36 and the catch 37, less the travelof the bolt necessary for releasing (or looking) detent 5 in place. The lug 37 is connected with the slider 38 which is movably connected to the bolt 35 for movement axially thereof; the free travel of the slider 38, i. e., without taking along the bolt, is the same as stated above. The spring 39 presses the slider in each time to an end-position, which makes it possible for the unlocking to start smoothly by gradually compressing spring 39 so as to increase graduallythe pressure tending to retract bolt 35; on the other hand it also serves to keep the slider quiet during the oscillation of the gear wheel 3. The bolt 35, which needs in this arrangement only a short travelover the top of pawl 5, is biased toward locking position by a spring 40, which tends to push the bolt to the left in Fig. 4.

In case the coupling mechanism fails, i. e., if

the front corner 31 of the pawl 5'does not catch behind the edge 32 of the cylinder indentation,

that is, if the edge 32 should be missed, a second or auxiliary clutch may be provided as by shaping the shoulder 41 (Fig. 5) of the indentation 43, (which corresponds to the locked position of the printing cylinder gripper 42) in the printing cylinder gripper cam 44, so as to form a substantially radial face at the rear of said indentation. This cam may, for example, be situated in one of the two oscillatory gears of the drive of the type-bed. As the gripper governing roll 45 falls into the indentation 43 at about the same time as the coupling mechanisms 5 catch in, and as the gripper cam 44 now changes its direction of revolution and begins to run synchronously with the printing cylinder 1, the printing cylinder would be carried along even if the coupling mechanisms 5 should fail to act, because the radial face at 41 would prevent overriding of the governing roll 45, thus compulsorily taking along the printing cylinder. In order to avoid release of the grippers 42 due to the pressure of the shoulder 41 on the roll 45, the gripper shaft 46 is arranged a little more distant from the cylinder shaft than the gripper roll 45. The grippers being locked, the roller arm 47 will have passed the dead point when it reaches the position shown in Fig. 5, so that the grippers are steadily pressed against the coacting parts during the time that roll 45 rests against the radial face of shoulder 41.

The rebound or chattering of the cylinder which occurs at the beginning of the standstillperiod immediately after the falling down of the stopping pawl, will be prevented by specially constructed locking pawls. This tendency of the cylinder to oscillate several times on its axis before it comes to rest will show itself in some quickly succeeding shocks against the stopping pawl, by which a rattling noise occurs, which is.

not only disturbing but also brings a certain restlessness into the machine. In order to avoid this, the stopping pawl 20 (Fig. 6) which prevents the printing cylinder from participating in the reverse movement of its shaft 2 and the gear wheel 3, bears an extension 49 reaching over the stop tooth 48, which is supplied on the side facing the. printing cylinder with a brake-block 50, which, influenced by the spring 51, presses itself fast against the printing cylinder as soon as the stop tooth 48 has fallen into the gap beyond the stop 19. In this way the chattering of the cylinder is prevented. In order to prevent the stop.

- tooth 48 from sliding on the casing of the impression cylinder during the operation of the cylinder a roller 52 is provided on the stopping pawl 20 or on its extension 49 which drops into a low place at 53 on the impression cylinder while the cylinder is at rest, whereas during the revolution of the cylinder it rolls on thesurface of its casing, so that the stop tooth will be lifted from it and thereby prevented from wearing.

Having thus described the invention what .stroke of the bed.

direction during the printing operation only, means for moving said bed to and from printing position, and means for holding the impression cylinder against rotation during the return 2. In a printing press,an impression cylinder,

sheet gripping means thereon, an opposed pressure cylinder, a reciprocating bed frictionally driven by said cylinders during the printing por-' tion only of its printing stroke, an oscillatory shaft on which the impression cylinder is free to-rotate, means for driving said shaft in both directions directly from the main drive of the ma chine, means for carrying the bed to and from printing position, means for coupling the impression cylinder to the shaft during the printing operation only, and means for holding the impression cylinder against rotation during the return stroke of the bed.

3. A device as in claim 2, including a gripper spindle on the impression cylinder for'operating said sheet gripping means, a rockarm-on the gripper spindle, means acting on said arm to rock the spindle, and means for coupling the impression cylinder to its shaft through saidrockarm in one direction of rotation of said shaft.

4. A device as inclaim 2, including a gripper spindle onthe impression cylinder for operating said gripping means, a rockarm on the gripper spindle, means for coupling the impression cylinder to its shaft through said rockarm in one direction of rotation of said shaft, a cam fixed to the impression cylinder shaft for rocking said spindle, said cam' having a low place permitting the grippers to become operative, said low place being shaped to engage the end of said rockarm and prevent movement of the impression cylinder about its shaft in one direction while per mitting such movement in the other direction.

5. In a printing press, an impression cylinder, sheet gripping means thereon, an opposed pressure cylinder, a reciprocatory bed driven by said cylinders during the printing portion of its forward stroke, an oscillatory shaft on which the impression cylinder is loosely journalled, gears secured to said shaft at the ends of the impression cylinder, means to couple the impression cylinder tothe shaft at each forward rotation of said gears and to release it at each backward rotation thereof, means for reversely driving said gears said means being connected directly to the main .drive of the machine, means for driving said bed when free from said cylinders including a base for a type form, a pair of racks on said base meshing with said gears respectively for driving said bed,-and means whereby the drive for said bed is disabled while the bed is engaged by said cylinders.

6. A device as in claim 5, said coupling means including detents adapted to clutch the impression cylinder to the gears approximately at'the time of reversal of the gears and to release said cylinder during reverse rotation of-the gears.

7. A device as in claim 5, said coupling means including detents on the gears adapted to clutchthe impression cylinder to the gears approximate- 1y at the time of reversal of the gears and torelease said cylinder during reverse rotation-of the gears, means for positively holding said detents in clutching position during rotation of the impression cylinder, and means for freeing ,the detents at the end of a complete rotation of the same.

8. A device as in claim 5, said coupling means including detents on the gears adapted to clutch the impression cylinder --to the gears approxi-' mately at the time of reversal of the gears and to release said cylinder during reverse rotation of the gears, a bolt for each detent, resilient means for moving the bolt into locking engagement with the detent when the same is operatively engaged with said cylinder, an actuating lug on said bolt, and fixed means for engagement with the lug approximately at the position reached by said lug when the gears are reversed for positively actuating the bolt.

9. A device as in claim 5, said coupling means including detents on the gears adapted to clutch the impression cylinder to the gears approximately at the time of reversal of the gears and to release said cylinder during reverse rotation of the gears, a bolt for each detent, resilient means for moving the bolt into locking engagement wi h the detent when the same is operatively engaged with said cylinder, an actuating lug slidable axially of said bolt, resilient means for moving the lug toward the front end of the bolt, a fixed stop for said lug located approximately at the position reached by said lug when the gears are reversed, said lug being independently movable over a distance equal to the combined thickness of the lug and-the stop.

10. A device as in claim 5, said coupling means including detents on the gears adapted to clutch the impression cylinder to the gears approximately at the time of reversal of the gears and to release said cylinder during reverse rotation of the gears, a belt for each detent, a slider for operating the bolt said slider being movable axially of the bolt, resilient means for moving the bolt toward locking position, resilient means for moving the slider in the same direction, a mg on the slider, and a fixed stop for the lug, whereby the slider may be moved independently of the bolt before it withdraws the bolt.

11. A device as in claim 5, said coupling means including detents adapted to clutch the impression cylinder to the gears approximately at the time of reversal of the gears and to release said cylinder during reverse rotation of the gears, a bolt for each detent, means for unlocking the bolts and unclutching said cylinder at the endof a rotation thereof, and means for cushioning the shock that occurs at the unlocking of the coupling mechanism.

12. A device as in claim 5, the bed being driven during-the primary and final parts of the forward stroke and during the entire return stroke by said gears and racks but being driven during the printing period solelyby the frictional engagement of the pressure cylinder and the impression cylinder.

13. A device as in claim 5, the bed being driven during the primary and final parts of the forward stroke and during the entire return stroke by said gears and racks and during the printing period solely by. thefrictional engagement of .the pressure cylinder and the impression cylinder, the distance between the gears and the corre'-- spending racks being greater than thatrequired by their pitch lines to provide play between the" shaft on which the impression cylinder is free to rotate, means for driving said shaft in both directions directly from the main drive of the machine, means for carrying the bed to and from printing position, means for coupling said cylinshaft driving means comprising a gear on the.

shaft, an oscillatory segment driving said gear whereby each stroke of the segment corresponds to a full rotation of the impression cylinder shaft, and means to drive said segment.

15. A device as in claim 14, the segment driving means comprising a rotating crank and a block-on the crank slidable in a radial slot in the segment so related to the impression cylinder shaft that the press is driven more slowly but with greater force during the printing stroke but faster and with less force during the return or idle stroke.

16. In a bed and cylinder printing press, an impression cylinder, sheet gripping meansthereon, a pressure cylinder, a bed driven during the printing portion of its forward stroke solely by the frictional engagement of the pressure cylinder and the impression cylinder, means for moving the bed to and from printing position, means independent of' the bed for rotating the impression cylinder during the printing operation only, and means for holding the impression cylinder against rotation during the return stroke of the bed.

1'7. In a printing press, an impression cylinder, sheet gripping means thereon, an opposed pressure cylinder, a reciprocating bed frictionally driven by said cylinders during the printing portion only of its printing stroke, an oscillatory shaft on which the impression cylinder is free to rotate, means for driving said shaft in both directions directly from the main drive of the machine, means for carrying the bed to and from printing position, means for coupling the impression cylinder to the shaft during the printing operation only, and means to stop the impression cylinder after each full revolution.

18. A device as in claim 17, the stopping means including a lug on the impression cylinder and a pawl on a fixed support said pawl being constructed and arranged to engage behind said stop and prevent backward rotation of the impression cylinder.

19. A device as in claim 1'7, the stopping means including a lug on the impression cylinder, a pawl on a fixed support said pawl being constructed and arranged to engage behind said stop and prevent backward rotation of the impression cylinder, and a brake movable with the pawl for engaging th impression cylinder.

20. A device as in claim 1'7, the stopping means including a lug on the impression cylinder, a pawl on a fixed support said pawl being constructed and arranged to engage behind said stop and prevent backward rotation of the impression cylinder, abrake movable with the pawl for engaging the impression cylinder, resilient means for actuating the pawl and the brake, and a roller acting on the surface of the impression cylinder to hold the pawl and the brake out of operative position, said impression cylinder having a low place to receive the roller when the impression cylinder is to be arrested.

21. In a bed and cylinder printing press, an

impression cylinder, sheet gripping means thereon, a pressure cylinder, a bed driven during the printing portion of its forward stroke solely by the frictional engagement of the pressure cyl1nder and the impression cylinder, and means for moving the bed to and from printing position including racks each resiliently connected to the bed.

22. A device as in claim 21, in combination with means independent of the bed for rotating the impression cylinder during the printing operation only, and means for holding the impression cylinder against rotation during the return stroke of the bed.

PAUL RAPPEPORT.

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