US2569034A - Hydraulic impression gear for printing presses - Google Patents

Description

Sept. 25, 1951 F. AUER HYDRAULIC IMPRESSION GEAR FOR PRINTING PRESSES 3 Sheeis-Sheet l Filed May 20, 1948 F. AUER Sept. 25, 1951 HYDRAULIC IMPRESSION GEAR FOR1 PRINTING PRESSES 3 Sheets-Shea?l 2 Filed May 20, 1948 Sept. 25, 1951 F, AUER 2,569,034

HYDRAULIC IMPRESSION GEAR FOR PRINTING PRESSES Filed May 20, 1948 3 Sheets-Sheet 5 Patented Sept. 25, 1951 HYDRAULIC IMPRESSIDN GEAR FOR PRINTING PRESSES- Frederick Auer, Teaneck, N. J., assignor to Champlain Company, Inc., Bloomfield, N. J., a corporation of New York Application May 20, 1948, Serial No. 28,107

(Cl. lOl- 247) 12 Claims.

This invention relates to printing presses, and more particularly to an hydraulic mechanism for controlling the printing pressure in the press, and also for raising and lowering the impression roller.

The invention is shown applied to rotogravure printing presses, especially of the multiple unit or multi-color type.- The web being printed is passed between a printing cylinder or drum which vis usually beneath the weband runs in a bath or fountain ofink, and an impression roller which is usually above the -web and squeezes the web against the printing cylinder or drum. (In the following specification the term drum is preferred for the printing cylinder, in order to distinguish from the hydraulic cylinders hereinafter referred to.)

It is not new to employ hydraulic cylinders and pistons to raise and lower the impression roller.

-The printing pressure has been controlled by positively arresting downward movement of the impression roller bearings by suitable adjusting means, usually stop screws beneath the bearings. With this arrangement the pressure depends upon the flattening of the bottom part of the periphery of the yieldable impression roller, which is usually made of rubber or equivalent material. Such an adjustment has proved neither convenient nor satisfactory, and has been particularly troublesome when dealing with a web such as glassine or cellophane which should be printed under a very light pressure, for in such case the adjustment of the stop screws is most critical and difficult. Paper may be printed at a pressure of, say, 100 to 400 lbs. per linear inch, and paper board at a pressure of, say, 250 to 450 lbs. per linear inch, but a glossy web, such as cellophane (regenerated cellulose) or glassine is best printed at a very light pressure of, say, to 60 lbs. per linear inch. With positive stop screws it is diicult to adjust the pressure toa value less than 100 lbs. per linear inch. Moreover, there is no convenient way to indicate the pressure being applied to the web, and the adjustmentis a painstaking and wasteful matter of trial and error.

The primary object of the present invention is to overcome the foregoing difficulty, and to provide a printing pressure ranging all the way down to zeropressure or so-called kiss contact, and all the way up to a desired maximum pressure. For thisfpurposera counterbalance pressure is applied beneath the pistons to counteract or more than counteract the dead weight of the impression roller and its bearingsand associated mechanism. The pressure'which is applied tov g the top of the pistons is so adjusted that the differential or net force applied to the impression roller provides the desired printing pressure per linear inch. It is evident that with this arrangement the printing pressuremay be reduced toA a very low value, and that even such low value, say 10 lbs. per linear inch, may be accurately regulated and maintained.

Moreover, in accordance with a further feature and object of the invention, a pressure gauge is connected toy thetop of the cylinder, and it is so arranged that it may be set at zero even though under some pressure, the zero setting being used for a kiss contact at the impression roller. The scale on the pressure gauge then may be used by the operator as a guide in quickly adjusting the printing pressure to a change in the nature of the web being printed,` and also as a guide during any'subsequent trial and error changes of a minor degree for obtaining optimum printing results.

In accordance with further features andvobjects of the invention, the bottom Yand top of the cylinder are supplied with pressure fluid from a common source capableof supplying a pressure somewhat greater than thatvneeded as a maximum forthe top of the cylinder, and a suitable iixed adjustable means is provided to regulate the counterbalance pressure supplied to thebottom of the cylinder, andanother suitable fixed adjustable means is employed to regulate the pressure supplied to the top Vof* the cylinder, yindependently of the pressure supplied to the botto of the cylinder.

As so far described, the downward movement of the roller from an elevated position wouldv be rather slow, and a further object of the invention is to provide a rapid movement of the roller from lits raised position downward to theprinting drum. This is done by releasing allpress'ure at the bottom of the cylinder during downward movement, and applying the counterbalance pressure at or near the end Vof the downward movement, and preferably in response to contact between the roller andy drum.

A further object is to. provide rapid upward movement of theroller, and for-this purposethe pressure is released from the top of thepiston, and the pressure applied to the bottom of the piston may be supplied directly from the source without passing through the pressure. adjusting means previously referred to.

StillA another object is to conserve hydraulic power and to `further speed up the movement. of theimpression roller. For this purpose two pressure sources may be used, one a low pressure source, and the other a high pressure source, the former being used for raising or lowering the roller, and the latter being used after the roller is in contact with the drum. Such sources may be provided in the form of a combination high and low pressure double pump and valve. Such double pumps have a large volume low pressure impeller, and a low volume high pressure impeller, together with a built-in valve which cuts off the low pressure supply and continues the high pressure supply when a back'pressure is built up exceeding the low pressure.

A further object of the invention is to provide for remote control of the raising and lowering of the impression roller, and for this purpose a main four-way valve is connected to the top and bottom of the cylinder, and is preferably of the solenoid type so that at any desired point, preferablyrincluding points at each side of the printing ,unit itself, a pair of pushbuttons may be prolvided, one for raising and the other for lowering the roller.

Still another object is to apply the invention I pressure of the unit, typically a pressure reducing valve leading to the top of the cylinder, is preferably provided individually for each of the units, because slight differences in printing pressure may prove desirable for the different colors being printed.

I, To accomplish the foregoing general objects, Iand other ,more specific objects which will hereinafter appear, my invention resides in the printjing press elements and hydraulic gear elements land their relation one to another as are hereinafter more particularly describedin the specificartion. The specification is accompanied by drawings in which Y Fig. lisa pipe diagram showing one preferred rform of my invention;

l Figs. 2 and 3 are schematic sections through a known commercially available form of combination high and low pressure double pump and valve V,which may be employed as a part of the invention;

Fig. 4 is a side elevation of a multi-color rotogravure printing press embodying features of the f invention;

Fig. 5 illustrates the remote pushbuttoncontrol for the hydraulic mechanism; Y

Fig. 6 is a schematic wiring diagram for the 'remote control wiring; and

Figs. 7, 8 and 9 are pipe diagrams explanatory ofthe operation of the invention during lowering of the roller, during printing, and during raising I of the roller, respectively.

Referring to the drawing, and more particularly Ato Fig. 4, the invention is shown applied to a multi-color rotogravure printing press comprising a wind-off mechanism l2 supporting a web roll I4 and feeding the paper to printing units I6, I 8, 20 and 22 from which the web is wound iup on a ree] 24. Referring to the printing unit "I6 as typical, the printing cylinder or drumis. shown at 26, and the web is fed around guide '4 rollers 28, 30 and 32 toan impression roller 34. The web is then fed to a dryer 36 by means of guide rollers 38, 40, 42 and 44, and then goes to the next unit. To avoid changing the length or position of the web, the guide rollers 32 and 38 are preferably raised, and lowered in unison with the impression roller 34. The impression roller 34 is raised and lowered by hydraulic mechanism schematically indicated at 46. It will be understood that in the particular printing units here shown, any reference to the hydraulic Vcylinder 46 raising or lowering the impression roller is to be understood as meaning the raising or lowering of the combination of rollers 32, 34 and 38.

The printing unit has a pushbutton panel 48 (Fig. 4) more clearly shown in Fig. 5, the said panel having two buttons 50 and 52 appropriately marked to indicate raising or lowering of the impression roller. All of the printing units i6, I8, 20 and 22 are preferably alike insofar as the present invention is concerned, and it will be understood that each has a pushbutton panel as described. In fact, one may be provided on each side of the press. However, in the particular arrangement here shown, the pushbutton panel is av remote control for al1 of the printing units, and pressure on the up button or down button will raise or lower all of the impression rollers which are in use. (It is possible to permanently 'cut out any desired number of the printing units 'suitable valve mechanism 60 is provided to apply pressure fluid from a source 62 to either the top or bottom of the cylinder in order to lower or raise the roller. An additional valve means 64 is provided to supply pressure fluid to the bottom of the cylinder through piping independent of :the valve means 60, thereby counteracting the dead weight of the impression roller and associated mechanism, such as the hydraulic pistons, rods, bearings and movable guide rollers, etc.

There is also a xed adjustable means, in this Vcase a pressure reducing valve 56, to adjust the pressure supplied to the top of the cylinders 46 in order to obtain a desired net differential force or printing pressure.

From another viewpoint it may be said that the main valve means releases the pressure at the bottom of the cylinder during lowering of the impression roller in order to obtain rapid lowering of the roller, while the additional means 64, which is a counterbalance or sequence valve, applies pressure to the bottom of the cylinder at or near the end of the downward movement of the roller.

The source 62 is in reality two sources, one at low pressure, and the other at high pressure.

Itis preferably a combination high and low pressure pump or double pump with a built-in valve to cut off the large volume low pressure Vsupply when back pressure builds up against the same. The pump inlet from the tank is shown at 14.

The main valve 60 previously referred to is preferably a solenoid operated four-way valve.

.pressure to high pressure. .suppliednot'only to `main valve 60 through pipe llophane is frictionally restrained yet .acampar Its .inlet from pump 62 is the pipe 68,-'its ALexi- :haust or 4drain y.outlet is .shown by pipe I0/leading baclr-to a tank 12. During lowering of the impression roller, uid is led by valve |30 to pipes 16, Island 'and so to the topof thefcylinder. Fluid is exhausted from the bottom of the cylinder :through pipes 82, 84, :86.andn88 to valve y|30 and thence through pipe '10 `to tank 12. During raising of the roller, pressure fluid guidedloy valve `|50 to pipes '88, 28, 84 and 82 to the bottom ofthe cylinder., while the top of the cylinder is released through pipes 80, 90, check valve 92, pipe 94, pipes T8 andfl to valve 60 and thence through drain pipe T to tankllZ.'

When the impression roller has been lowered into-contactwith the printing drum, back pressure builds up, and pump 62 changes from low vThe high pressure is 68, .and so to the top of the cylinder, but also through a pipe et to a now control valve 98 and a check valve 00 and thence through pipe |02, counterbalance and sequence valve 54, pipes 86, 84 and 82, to the bottom of the cylinder. The

vlpressure thus applied to the bottom of the cylin- ,der is limited to a desired amount, and this is preferably done by means of a pressure relief valve |84 which permits some of the fluid passed by the flow control valve 98 to bleed back to thetank through pipes |06, 88, four-way valve -60,drai-n pipe '|0 and thence to tank 12.

pressure, the coun-terbalance and sequence valve |54 is shifted in such a direction as to connect pipe |02 with pipe 85, the pipe 88 being disconnected from pipe 86 and thereby terminatingren lease or free drainage from the bottom of the cylinder to the tank l2.

The pressure relief valve |04 is sokadjusted relative to the flow permitted by the flow control valve 98 as to providea desired upward or counterbalance pressure at the bottom of the cylinder. The pressure gauge ||0 may be added temporarily during servicing of the apparatus to determine the pressure supplied to the bottom of the cylinder. The pressure gauge ||2 reads the high pressure from the pump 62,.and thistoo is adjusted to keep. it atsome value reasonably close-.to the maximum pressure needed at the top of the cylinder. The actual pressure supplied to the top of the cylinder is adjusted by the pressure reducing valve 00 previously referred to, and any7 overflow or drainage from the pressure reducing valve is led. byV means ofpipes ||4 and H to the tank 12. The pressure gauge H8 is left permanently with the apparatus, and may be lused as a measure of the printing pressure. To do this the gauge is set at zero when the impression roller just touches` the printing drum,

practical. matter, may be determinedby placing a strip of cellophane between the roller and drum and regulating the pressure until the celcan be pulled through the rollers. Y'

Multiple printing units are controlled from .6. the samepump andg'v'alve arrangement sc zfar described; this being represented'in Fig.. 1 by the rcylinders '46" connected tothe main pipes and 84 previously referred to by .means of presi sure reducing valve 68", check valve '92. and pipes 82T, '30.'. 90, .94. 'Ihezuse'of individual pressure reducing valves 'B6 .andv etc. makes it possible to independently adjust the printing: pressure at the different printing'units, as-indicated by the vindividual gauges'HS, 4| l0', etc.

The particular pumpv '62 here shown is manufactured by Vickers, Inc., of Detroit,`Michig-an, and is their 'unit No.` VCH1109-ED3DB.AV 'The operating principle ofthe double pump and com- .bination valve unit is kshown in Figs.` 2 and 3 of the drawing; There is a small volumehigh pres; 4sure pump |20 and a large Volume low pressure pump |22. These have `a common inlet |24. The high pressure pump |20 is continuously connected to an outlet |26. The low pressure pump |22 is, connected to the same outlet |28 Vthrough acheck valve |28. The pump further comprises a pressure actuated unloading valve schematically vindicated at |30, ran overload relief vvalve schematically indicated at |32, and acontrol chamber schematically indicated at |34. In Fig. v2 the pumpis operating at low pressure, and the-large output of pump |22; say` 14 gals. per minute; is joined with the small output, say 1 gal. per mine ute, from the pump |24, the combined flow being delivered at the 'outlet |26. The unloading valve |30 -may `be externally yadjusted to open if the back pressure in control chamber .|34 rises to a pre-'determined value.' When'the pressure in the control chamber |34 is less than'the arilji'istm'ent, the rvoil flow is combined in outletl26`; the'check valve |28 being opened andthe overload relief valve |32 being inoperative. Some low pressure iluid ilovvs through pipe |08.

As the back pressure rises until thepressur'e in controlchamber |34 exceeds the adjustment of the unloading valve |30, the unloading valve opens and permitsall of the oildelivered by the large pump |22 toflow freely back to the tank or reservoirv without any .resistance AandV without consuming power. TheY condition is illustrated in Fig.'3 of the drawing. -In effect,` there is a connection within the pump back lto vits inlet. The

ycheckvalve 1| 28 closes and the small volume pump |20 continues to supply fluid under high pressures to the outlet |26. The high pressure may itself'becontrolled by theV overload relief'valve No low pressure fluid-flows through pipe Thelfour-Way valve 60 might be mechanically operated, but it is convenientytoprovide remote control, and this inturn is most conveniently done by electrical means.- The'valve is: accord'- ingly-a'solenoid operatedvalve, and in the particular case here shown,A it is f manufactured by Vickers, Inc., of Detroit, Michigan; it '"being their solenoid operatedfour-way' valve -Noi Gli-2632- `I\TA-220ACSC. It' isbelieved unnecessary toex'- plain the Ainternal construction' of .a four-Way valve; andmanytypes arev knownand available on the market. In liig. lvit'willbe' understood that .the valvel itselfjis contained' in the' central poi'- vtion, theen'd portions |40 and |42 representing the solenoids which shift the valve towardthe right or the' left. The electrical control of such a valve is quite simple, -it being shownv at Fig. 6,

:in-which the circuit to solenoid |48 may be closed by means. of v'a remote pushbutton 50, while the v-circuitto the-solenoid 42 may be closed by means vcfa companion pushbutton 52.y There isa com'- solenoid operated valve at additional remote control points, it is merely necessary to extend wires as shown at |48, running, for example, along the press from printing unit to printing unit, and to connect additional up and down pushbutton panels at desired points, as indicated at |44 and |46 inFig. 6.

The flow control valve 98 may be of any conventional type. That here shown is a Vickers, Inc., FX-l90-D ilow control valve.V 'I'he check valves 92 and |00 may be conventional, one commercially available type being made by Watson- Stillman, and another commercially available type being made by Vickers, Inc., the latter being their No. Cd805 check valve. Check valve 82 is faced to permit downward iiow, and the check valve is faced to permit upward flow, as viewed in the drawing.

'I'he pressure relief valve |04 may be conventional, that here shown being a Vickers CRf-l'l-B relief valve.

'I'he pressure reducing valve 66 may be conventional, the particular one here shown being a Vickers X-106-DK.

A shut-off valve |52 may be provided beneath the pressure reducing valve 66. This may be closed when it is desired to cut a printing unit out of operation, and also on occasion during servicing and adjusting operations. Release can still take place through check valve 92, hence the roller can be urged upward, but not downward.

The counterbalance and sequence valve 64 is `in this case made by Vickers, Inc., it being their series RC-106-Z-4 valve. Other known valves may be used, the important thing being that the valve be able to connect pipe 86 to either the pipe 88 or the pipe |02, and that it be responsive to a change in pressure. In the present case the application of low pressure through the pipe |08 holds the valve in that direction which connects pipe 86 to pipe 88. However, when the valve action of the pump itself bypasses the low pressure supply so that no further low pressure fluid is delivered to pipe 08, and instead the low pressure iluid is released directly back to the tank 12 or to the pump inlet, the valve 64 shifts in such a manner as to connect the pipe 86 to the pipe |02 instead of to the pipe 88, whereupon the bottom of the hydraulic cylinder, instead of draining into the tank, is supplied with pressure iluid, the precise pressure of which has been determined by the adjustment of the pressure relief valve |04. A The three main stages of operation ofthe apparatus shown will be clear from inspection and comparison of Figs. 7, 8 and 9l of the drawing. In these figures the active pipes have been shown in heavier lines in order to simplify the drawings and the explanation. Referring to Fig. 7, it Will be seen that the piston 56 is being forced downgwardly by low pressure iluid supplied from pump 62 through valve 60, pipes "I6 and 18, pressure -reducing valve 66, and pipe v8|), to the top of the cylinder 46. The bottom of the cylinder drains freely through pipes 82, 84, 86 and 88, valve 60,

Atacts the printing drum, the situation becomes that illustrated in Fig. 8. Back pressure builds up and the low pressure pump is cut out 'of operation. The high pressure pump supplies high 'mon power supply, as shown. To control the' pressure iluid through valve 60, pipes 16 and 18, pressure reducing valve 66 and pipe 80 to the top of the cylinder. At the same time the cut-oii' of low pressure through pipe |08 to the counterbalance and sequence valve 64 causes that valve to shift and to connect pipe 86 with pipe |02. At this time, therefore, some of the high pressure uid iiows through pipe 96, ilow control valve 98, check valve |00, and thence upward through pipe |02, valve 64, pipes 86, 84 and 82, to theA bottom of the cylinder. This opposes and counteracts or more than counteracts the dead Weight of the impression roller and its associated mechanism. The amount of counterbalance pressure is determined and limited by the pressure relief valve |04, which permits some of the fluid to ow back through the pipe |06 and pipe 88 to valve 60 and drain pipe 10. The pressure provided through the pressure reducing valve 66 is so adjusted, relative to the counterbalance pressure, as to result in a net downward force which gives the desired printing pressure, ranging anywhere from zero or kiss contact upward to, say, 500 lbs. per linear inch.

The conditions which prevail when the impression roller is being raised are shown in Fig. 9, in which it will be seen that the top end of the cylinder is released through pipes and 80, check valve 92, pipes 94, 18, and 16, to the fourway valve 60, and thence to the drain pipe 10. At the same time low pressure iluid, ordinarily the combined output of the low pressure and high pressure pumps, is supplied from valve 60 through pipe 88, valve 64, pipe 86, pipe 84, and pipe 82 to the bottom of the cylinder. The resumption of low pressure supply is, of course, applied through pipe |08 to the valve 64, thus shifting it to a. position which connects the pipes 86 and 88.

In setting up the apparatus, a theoretical procedure would be to iirst cut oif pressure to the top of the cylinder and to the bottom, permitting the impression roller to come down of its own weight, and to then open up the adjustment o1' the pressure relief valve |04 until the impression roller begins to creep upwardly. A piece of ce1- lophane may then be placed between the roller and the drum, and the supply of pressure to the top of the cylinder may be resumed, the pressure reducing valve 66 then being adjusted until the cellophane is frictionally restrained yet can be pulled between the rollers. At this time the printing pressure gauge ||8 is preferably set to zero. The desired printing pressure is then obtained by opening up the pressure reducing valve 60 further to increase the pressure at the top of the cylinder.

In practice this procedure is modified to specify an actual pressure for the bottom of the cylinder, as learned by experience for a particular type of press. This figure is supplied to the serviceman as a part of his instructions, and is usually somewhat more than is needed to just counterbalance the dead weight of the impression roller and its associated mechanism. In the particular case here illustrated, the pressure is lbs. per square inch, as determined by a pressure gauge ||8 (Fig. 1) temporarily connected to the piping. The top pressure is then applied until the roller and drum just hold a piece of cellophane, as above described, whereupon the printing pressure gauge ||8 is set to zero. The pressure reducing valve 66 is then opened up to obtain a desired printing pressure.

In theory the bottom pressure may be made "that type.

excessive. are tte top ere feerereem th @ese-^' Itis believed1thlv`ee.I lstrletlep 'arid AOpere-Y bien ef 'mrimpevedfhydreulidev emifeeem @felling the impreSSieeeHer' 'elf tingfpreee as well as theadnl parent :fromtlie'ffre` Themain advantag Y Y.

sure may' be djiiste'd with gra-duet control an the'way from 'zero'orkiss 'conta Y 'ward oV y desired maximum pressrel j "Ihis `1s pl t 1 c`ul ly iiportantv when printirig `webs' which require *a T,

Otheradvaptaeesare ,that the impreeeien teller may ,be lowered vrapidly and ,raised rapidly en@ this movement may be Qbtained withY 19W p1; Si sure fluid, and conseqpent eeonemy- .The arrangement prei/idee fer .remeteeolltlel of the impression roller, and for control at any station alongV the press.- It also affords simultaneous operation of all of the impression rollers. This is some times` important, because in an emergencyit maybe desiredto quickly relieve the pressure of all oftheimpression rollers. Although" all of. the units are operated simultaneously, thisA does'not mean `that all of theV units must'be kept inv operatiomand any one or more of the printing unitsmay be cut out ofoperay and described my' invention in'a preferred form', l

vchanges may lbe Inad'e'v inthe structure shown without departing from the spirit'of the invention asl sought tol be vdefined in 'the followingl claims. In the claims, for c'onvenience', reference is 'made lto supplying pressure ltofthe'top'of the cylinder ,-e

or the bottom of the cylinder, VandV it will be lun'- derstood that topof the'cylinder means thatend which moves the impression roller against Athe 'printing drum, and bottoni of thejcylinder means that end which separates Vthe impression'roller "from the printing drum. "Also the vimpression roller is said to be moved bythe pistons, butthis is not intended toeiclude an obvious reversal of parts in which the .'pistons might be stationary "and the cylinder movable andconnected to the impression roller. 4The printing `crsylinder is referred to as a drum, and the impression @vlinder iereferredieese rellen in Order te help distinguish fremvtheterm eylinder 'eS ap- 'plied to the hydrauliccylinder.""Referenceto raising or lowering theirnpressionroller is intended to' include reisijrrgand lowering gri-,ige

'rollers .associated with it wpepthelpresszis ,ef

lelem 1 to bination, a printing press having a printing drufn, anhyd'ailic-"cylindr and `piston;` andfan i'rnprssion roller" raised and lowered? by said piston, fasource' of' pressure 'ui'df a valve nichanisni' betweens aidl` so'ur'ce' and" said* hy= dra'u'lic "cylindertdraise or lower the'- impression roller; yIn'far's" responsive' tO'the bili-loting lip' Of hackv pressure infthe "supply'to theto'p` ofthe cylinder: ito"vaiitomatioally'connect -the 'source'v to sure supplied t"the"b p l lorder "tciinteract i dead weight o'f "the impression iollerad a' oc 'ted mechanism `carry; .ig ne sa e, 'and a edadjnstaplemee' adjust: the pressure suppliedto the topv eyundetd otteiant 'rind anywhere fr'omv ze'rok deelnemende@ Y. nature of 4deert/eb bei 3.111 eerebeelie, 1151 printing drum, ehrdrelie ,ieder ,end pisiien; and ian impression rollrrai's'dfand ylo e'edby ser@ pieten; e seur'eeef @essere den; operated ,teur-Wer. ,Valve betweefa s" ,said hydraulic cylinder te fese'wee pression-rollen. ineens rele eil/ete the bllldg upor backpressurein the ,eupnlf 'te fthe tef'e the wunder to automatieallrfeeeneeli 'the .Sllree te thebettem ef thehydreulieeylpder wheeiti roller contactstheprinting d angled adjustable pressure felefvel-ve et-ediuet the @1111??? balance pressure supplied-:te theileetterl. ef the `cylinder inforder lto counteract the cad weight of theimpression roller and' assoc teg lllhn; 'nism :carryingthefsamaiand a-g v ed adjustable pressure reducing '-val-ve between-the four-Way --Valve' and the top of the hydraulic cylinderf to 'adjust'the-fpressuresupplied'to lthe top' o f (the `cylinder to .,obtainfa netprinting pressure ranging anywhere fromfzero orfkiss contact upwardfvto a desired maximum' pressure depending pppn; the natureof theewebbeingprinted; 'P41` In` combinatidngfa printing press havingua printing drm; an' hydraulic".cylinderand piston, `and'Y an impression roller" raised `'and `lf'nweredloy "said ipisto'n; `al""sou1ne`4 of 'highf pressure' i flu-idr?- a -source of" low pressure :fluidi 'a Avalve gto; .ichange fro'rthe lw `to'thelhighipressure'"Esourcerlwhen increased resistance is-'e'ricount'eed vali/eimerhapressure' 'reapply 'ount "rbeliarjcef pressure te I the jrs f'bttomf the riverain" csf-Linder iwhnitnefrouer contacts the printing drum,l means to adjust the counterbalance pressure vsupplied to the bottom of the cylinder to counteract the dead weight of the impression roller and associated mechanism carrying the same, and means'to adjust the pressure supplied to the top of the cylinder to obtain a net printing pressure depending upon the nature of the web being printed.

5. In combination, a printing press having a printing drum, an hydraulic cylinder and piston, and an impression roller raised and lowered by said piston, a combination high and low pressure double pump and valve including means to deliver high instead of low pressure when the back pressure on the pump builds up, a four-Way valve between said pump and said hydraulic cylinder to raise or lower the impression roller, means responsive to a change of pump action from low to high pressure to apply a counterbalance pressure to the bottom of the hydraulic cylinder when the roller contacts the printing drum, means to adjust the counterbalance pressure supplied to the bottom of the cylinder-to counteract the dead weight of the impression roller and associated mechanism carrying the same, and means to adjust the pressure supplied to the top of the cylinder to obtain a net printing pressure ranging anywhere from zero or kiss contact upward to a desired maximum pressure depending upon the nature of the web being printed.

6. In combination, a rotogravure printing press having a printing drum, an hydraulic cylinder and piston, and an impression roller raised and lowered by said piston, a combination high and low pressure double pump and valve including means to deliver high instead of low pressure when the back pressure on the pump builds up, a solenoid operated four-way valve between said pump and said hydraulic cylinder to raise or lower the impression roller, a counterbalance sequence valve responsive to a change of pump action from high to low pressure to apply a counterbalance pressure to the bottom of the hydraulic cylinder when the roller contacts the printing drum, a fixed adjustable pressure relief valve to am'ust the counterbalance pressure supplied to the bottom of the cylinder to counteract the dead weight of the impression 'roller and associated mechanism carrying the same, and a fixed adjustable pressure reducing valve between the four-way valve and the top of the hydraulic cylinder to adjust the pressure supplied to the top of the cylinder to obtain a net printing pressure ranging anywhere from zero or kiss contact upward to a desired maximum pressure depending upon the nature of the web being printed.

7. The combination with a printing press having a printing drum, an impression roller, an hydraulic cylinder and piston for raising or lowering the impression roller, and a source of pressure fluid, of valve means to supply pressure fluid to the bottom of the cylinder, valve means to supply pressure fluid to the top of the cylinder, xed adjustable means to adjust the pressure Vsupplied to the top of the cylinder to obtain a desired net differential force or printing pressure depending upon the nature of the web being printed, additional means to release the pressure K..,..12v 8. The combination with 'a vprintingv press having; a printing drum, an impression roller. an hydraulic cylinder and piston for raising or low# ering the impression roller,.an d a source of pressure fluid, of Valve means to supply pressurefluid to the bottom of the cylinder, valve means to sup--` ply pressure nuid tothe top of the cylinder, xed adjustable means to Yadjust the pressure supplied to the top of the cylinder to obtain a desired net differential force or printing pressure depending upon the nature of the web being printed, two sources of pressure iluid, one at low pressure and theY other at high pressure, means to connect the low pressure source to thetop of the cylinder during lowering of the roller, and means responsive to the building up of back pressure in the supply to the top of the cylinder to automatically connect the high pressure source to the top of the cylinder at or near the end of the downward movement of the roller.

9. The combination with a printingpress having a printing drum, an impression roller, an hydraulic cylinder and piston for raising or lowering the impression roller, and a source of pressure fluid, of valve means to supply pressure fluid to the bottom of the cylinder, valve means to supply pressure uid to the top of the cylinder, lixed adjustable means to adjust the pressure supplied to the top of thecylinder to obtain a desired net diilerential force or printing pressure depending upon the nature of the web being printed, two sources of pressure fluid. one at low pressure, the other at high pressure, means to connect the low pressure source to the top of the cylinder during lowering of the roller, means to release the pressure at the bottom of the cylinder during lowering of the roller, means responsive to the building up of back pressure in the supply to the top of the cylinder to automatically connect the high pressure source to the top of the cylinder at or near the end of the downward movement of the roller, and means responsive to the change to the high pressure source to automatically apply pressure to the bottom of the cylinder at or near the'end of the downward movement of the roller. I

10. The combination with a rotogravure printing press having a printingfdrum, an impression roller, an hydraulic cylinder and piston for raising or lowering the impression roller, and a source of pressure iiuid, a valve means to supply pressure fluid to the bottom of the cylinder in order to counteract the dead weight of the impression roller and associated mechanism carrying the same, fixed adjustable `means to adjust the counterbalance pressure supplied to the bottom of the cylinder, valve means to supply pressure iiuid to the top of the cylinder, xed adjustable means to adjust the pressure supplied to the top of the cylinder to obtain a printing pressure ranging anywhere from zero'or kiss contact upward to a desired maximum pressure depending upon the nature of the web being printed, means to release the pressure at the bottom of the cylinder during lowering of the roller for rapid lowering of the roller, and additional means responsive to the building up of back pressure in the supply to the top of the cylinder to automatically apply the aforesaid counterbalance pressure to the bottom of the cylinder when the roller contacts the printing drum. l

1l. The combination with a rotogravure printing press having a printing drum, an impression roller, an hydraulic cylinder and piston for raising or lowering the impression roller, and a source of pressure fluid, of valve means to supply pressure fluid to the bottom of the cylinder in order to counteract the dead weight of the impression roller; and associated mechanism carrying the same, fixed adjustable means to adjust the counterbalance pressure supplied to the bottom of the cylinder, valve means to supply pressure fluid to the top of the cylinder, xed adjustable means to adjust the pressure supplied to the top of 121.11l cylinder to obtain a printing pressure ranging anywhere from zero or kiss contact upwardto a desired maximum pressure depending upon the nature of the web being printed, two sourcesof pressure fluid, one at low pressure, and

the other at high pressure, means to connect the A,

low Vpressure source to the top of the cylinder during lowering of the roller, and means responsive to the building up of back pressure in the supply to the top of the cylinder to automatically connect the high pressure source to the top of the cylinder when the roller contacts the printing drum.

12. The combination with a rotogravure printing press having a printing drum, an impression roller, an hydraulic cylinder and piston for raising or lowering the impression roller, and a source of pressure fluid, of valve means to supply pressure fluid to the bottom of the cylinder in order to counteract the dead weight of the impression roller and associated mechanism carrying the same, xed adjustable means to adjust the counterbalance pressure supplied to the bottom of theA cylinder, valve means to supply pressure uidto the top of the cylinder, iixed adjustable means to adjust the pressure supplied to the top of the cylinder to obtain a printing pressure 14 ranging anywhere from zero or kiss contact upward to a desired maximum pressure depending upon the nature of the web being printed, two sources of pressure fluid, one at low pressure, the other at high pressure, means to connect the low pressure source to the top of the cylinder during lowering of the roller, means to release the pressure at the bottom of the cylinder duringlowering of the roller, means responsive to thevbuilding up of back pressure in the supply tothe top of the cylinder to automatically connect vthe high pressure source to the top of the cylinderlwhen the roller contacts the printing drum at the end of the downward movement of the r'roller, and means responsive to the change to the high pressure source to automatically apply the aforesaid counterbalance pressure to the bottom of the cylinder when the roller contacts thevprinting drum at the end of the downward movement of the roller. 1

' FREDERICK AUER..

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

UNITED STATES PATENTS Number Name Date 1,771,750 Ellis July 29, 1930 2,111,134 Allin Mar. 15, 1938 2,194,078 Simonds Mar. 19 1940 2,205,720 Goebel et al June 25, 1940 2,206,620 Schwartz July 2, 1940 2,216,565 Eckhard Oct. "1, 1940 2,267,380 Tyler Dec. 23, 1941 2,281,900 Weiking May 5, 1942

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