Adjusting Arrangement For Ink Fountain In Printing Press

Abstract

An arrangement for adjusting the blade in an ink fountain which includes a set of rotatable keys, each of the keys carrying a frictionally engaged radial stop cooperating with a fixed stop to limit the angle of the adjusting movement of the key. A tool fitting is provided at the outer end of each key for manually rotating the key, with the stops in engagement, to adjust minimum blade clearance. A frictionally engaged pointer coupled to the key, is settable in accordance with the position of the radial stop to provide constant visual indication of the key adjustment. Each key has an electric friction type clutch for coupling the key to a rotatable shaft to provide running adjustment of running film thickness. The friction connection between the radial stop and the key is set to permit manual overpowering of the connection, and hence a change in the phasing of the radial stop, by a tool fitting on the outer end of the key in order to take up for blade wear and reestablish minimum clearance.

Description

It is an object of the present invention to provide an adjusting arrangement for an ink fountain in a printing press which permits quick and easy adjustment of the blade originally, for minimum clearance, and which limits the adjusting movement of the key to substantially a single turn to define maximum as well as minimum clearance. It is another object of the invention to provide an adjusting arrangement for an ink fountain in which the stop on a key is coupled to the key by a friction connection which provides a reaction torque which is sufficiently high to maintain the stop in a constant phase relation with respect to the key during all normal adjustment of the key but which is sufficiently low as to permit manual overpowering, when required, to take up for wear on the blade and to reestablish the minimum clearance condition.

It is another object of the invention to provide an adjusting arrangement for an ink fountain having a plurality of keys and in which the adjusted condition of each key is constantly displayed by a pointer upon an individual calibrated scale and in which there is provision for adjusting the pointer to reference position upon the making of any change in phase between the key and the stop which it carries.

It is yet another object of the present invention to provide, in system as characterized above, individual electric clutches for coupling each of the keys to a common reversible drive shaft for remote control of the film thickness at each key position.

Other objects and advantages of the invention will become apparent upon reading the attached description and upon reference to the drawings, in which:

FIG. 1 shows a side elevation of an ink fountain constructed in accordance with the present invention and with the "near" side plate removed to reveal the internal construction.

FIG. 2 is a fragmentary elevation looking along the line 2--2 in FIG. 1 in showing typical keys and their associated pointers and calibrated scales.

FIG. 3 is a fragmentary elevation looking along the line 3--3 in FIG. 1 showing the clutch profiles and with the keys in reference position.

FIG. 3a is an exploded sectional view of a threaded collet used in the present invention.

FIG. 4 is a diagram similar to FIG. 1 and showing the original adjustment for minimum blade clearance.

FIG. 5 is a diagram similar to FIG. 4 but showing the backing off of a key by engagement of its associated clutch to adjust running clearance.

FIG. 6 shows overpowering to reestablish minimum blade clearance accompanied by resetting of pointer to reference position.

While the invention has been described in connection with a preferred embodiment, it will be understood that we do not intend it to be limited to the particular embodiment shown but intend, on the contrary, to cover the various alternative and equivalent constructions included within the scope and spirit of the appended claims.

Turning now to the drawings there is shown an ink fountain 10 having a frame 11 mounting a blade 12. The blade has a cantilevered edge 13 which extends longitudinally along a fountain roller 15. The blade is engaged along the edge by the adjusting means to be described to provide a desired running clearance between the blade and the roller, thereby to convert a body of ink 16 into a film of predetermined thickness 17 as the roller 15 is rotated. It will be understood that conventional means (not shown) are provided for journaling the roller 15 in the frame and for rotating it slowly in the direction shown. The illustrated fountain is of the "undershot" type, but it will be apparent as the discussion proceeds that the invention is equally applicable to fountains of the "overshot" type in which the film is formed on the upper surface, rather than on the under surface, of the roller.

Spaced along the edge of the blade at equal intervals are a series of key assemblies which are substantially identical to one another. Each assembly includes a key 20 having a shank 21 which carries a thread 22 which is screwed into a tapped hole provided in frame 11. At its forward end the key has a blade engaging tip 23, while at its outer presented end the key has a tool fitting 24 to which a wrench W (FIG. 4) may be fitted for manual adjusting purposes.

In accordance with the present invention each key is provided adjacent its outer end with a radial stop which cooperates with a fixed stop mounted on the frame to limit the range of adjusting movement of the key, with a friction connection or coupling, being interposed between the radial stop and the key so that the key may be turned in the advancing direction, with the stops in engagement, to establish a condition of minimum clearance between the blade and the roller at the key position, following which the key may be rotated backwardly through an angle which is limited by the stops to establish a desired running clearance for production of an ink film of predetermined thickness. More specifically in accordance with the invention, the key carries a threaded collet near its presented outer end which mounts the radial stop and which is adjustable to provide a predetermined high level of frictional reaction torque capable of being manually overcome by a wrench or similar tool engaging the outer end of the key for takeup of blade wear from time to time and reestablishment of the desired reference condition of minimum blade clearance.

Thus turning to the drawing, a collet 30 is provided which is telescoped over the shank of the key 20 and which has an inner portion 31 and outer member 32. The inner member 31 is in the form of a hollow cylinder or bushing of conical shape having a taper-threaded portion 33 which is longitudinally slotted as indicated at 44 and which has a hub 35 mounting a radially extending stop 36. The outer member 32 of the collet has a tapered internal thread 37 which mates with the thread 33 as well as a hexagonal head 38 which is engagable by a collet wrench CW (FIG. 4). It will be apparent that when the outer collet member 32 of the collet is turned, for example, by means of the wrench CW, so that the threads 33, 37 are increasingly engaged, the slotted inner member 31 will be clamped in snug frictional engagement upon the shank of the key thereby to clamp the radial stop 36 in a desired phase position.

Arranged in the path of movement of the radial stop 36 is a fixed stop 40 which is anchored in a registering opening in a longitudinally extending mounting plate 41 which is in turn secured to a longitudinally extending bracket plate 42 which forms a part of the fountain frame. The threads in the collet and on the shank of the key are of the same hand so that the collet is tightened by rotating the outer member or collar 32 with the stops bottomed in the "minimum clearance" direction.

In accordance with one of the aspects of the present invention means are provided for giving constant indication of the blade clearance which exists at the key position. For this purpose we provide a pointer member 50 having a pointer 51 and a body 52 in the form of a loop, or clip, of spring metal which is seated in an annular groove 53 formed in the outer, or visible, end of the collet and which is inwardly sprung to provide a friction connection with the collet. Such friction connection, as will appear, enables readjustment of the pointer to a reference condition whenever there is a change in the reference position of the radial stop 36 with respect to the key upon which it is mounted. In order to provide calibrated scales for each of the pointers, a panel 60 is secured to the frame of the fountain having clearance openings 61 which register with the keys. Surrounding each of the clearance openings is a calibrated scale 62.

Prior to considering a typical stop-adjusting procedures, reference may be made to the means for remotely adjusting each key within the range of adjustment provided by the stops. Referring to FIG. 4 an electric clutch 70 is provided which is of annular shape and which includes an input element 71, and output element 72 and a stationary armature 73. The input element is in the form of an annular ring 74 of magnetic material mounted upon a spring spider 75 which is secured at its inner end to an input sleeve 76. Arranged closely adjacent to the input element is an annular output element 77 formed of magnetic material and having an annular insert or liner 78 imbedded in its face to provide predetermined frictional characteristics. The output element includes a hub 79 which is coupled to the shank 21 by means of a key or gib 80.

In order to establish a magnetic field between the input and output elements 71,72 the armature 73 has an annular coil 81 which is energized via a pair of leads 82. To maintain the armature stationary and thus to avoid necessity for any electrical slip rings, the armature is provided with an arm 83 which extends upwardly into register with a groove 84 formed in the bracket plate 42. Clutches of this type are commercially available under the trade mark "Electroid".

To rotate the sleeve 76 which is connected to the input drive shaft 90 in one direction or the other, a drive shaft 90 is provided which may be manually driven in opposite directions, or power driven, by suitable driving means (not shown) but which may include a pulley 91 connected to the end of the shaft. Arranged at intervals along the shaft 90 are worm gears 92, one in each key position. Each worm gear 92 is in constant running engagement with a gear 93 formed at the inner end of the sleeve 76 which is connected to the clutch input element 71.

For the sake of compactness the clutches 70 may be arranged in interfitting or staggered relation (FIG. 3) in two rows, with the sleeves 76 in two different lengths. When it is desired to rotate one of the keys 20 in one direction or the other under remote control to adjust the blade at the particular key position, the clutch 70 corresponding to the key position is electrically energized from a control console (not shown). The resulting field of magnetic flux causes the input and output elements of the clutch to be drawn together into frictional engagement so that the output element rotates the key 20 in one direction or the other depending upon the direction of rotation of the shaft 90. During the adjustment the armature 73 of the clutch is held stationary by its associated arm 83. After the key has been rotated through a desired angle the clutch is disengaged, whereupon the spring 75 draws the input element 71 away from the output element, depositing the key in a position to produce a film of desired thickness. Each clutch 70 is adjusted so that the torque which may be exerted at the clutch face is less than the reaction torque of the collet 30. Thus in the event that the clutch is electrically energized for too long a time, bringing the stops 36,40 into bottoming engagement, the stops will prevent any further rotation of the key with the result that there is idle slippage at the clutch faces. Consequently there is no possibility that a key will be advanced unduly to force the engaged blade into jamming or scraping engagement with the surface of the fountain roller.

The procedure employed for establishing an original adjustment of minimum blade clearance will be understood upon reference to FIG. 4. In making the clearance adjustment it will be understood that the clutch 70 is disengaged and that the key is initially in a backed off condition. The wrench W, fitted to the fitting 24 at the outer end of the key, is provided for rotating the key manually while a wrench CW fitted to the hexagonal head 38 of the collet serves to loosen or tighten the collet with respect to the shank of the key. The outer collar of the collet is preferably backed off so that the collet only has light frictional engagement with respect to the key.

Under such conditions the wrench W on the key is manually rotated to advance the key so that it presses the blade in the direction of the roller. To determine when the blade is in a reference position of minimum clearance, a shim S having a thickness of, say, 0.0002 inches is inserted between the blade and the roller with roller stationary. When a slight drag is felt upon the shim as it is moved back and forth between the blade and the roller it will be understood that the blade is in desired reference position and the wrench W is turned no further. In order to insure that the stop 36 on the collet is in a corresponding reference position, and to hold it in reference position, the collet wrench CW is rotated in the same direction as the wrench W thereby pressing the radial stop 36 in bottoming engagement with the fixed stop 40. Since the fixed stop blocks rotation of the inner member 31 of the collet, any continued rotation of the wrench CW serves to rotate the outer collar 32 in a direction to produce increased engagement of the threads 33,37, thus crowding the slotted inner member 31 of the collet into snug engagement with the shank of the key. The outer collar 32 of the collet is tightened to the point where approximately 30 in.- lbs. of torque are required to rotate the key with respect to the collet with the collet held in its stationary bottomed position. This is about double the maximum rated torque of the clutches 70, and is achieved, in a practical case, by tightening the collar 32, by wrench CW, to a torque level of 45 to 60 in.- lbs.

After the collet has been tightened the pointer 51 is moved to its reference, or zero, position on the scale 62. The process is repeated at each of the key positions so that the entire edge 13 of the blade 12 is at the same reference (minimum) spacing with respect to the surface of the roller.

In order to adjust a given key to provide a desired running film thickness, the clutch 70 is engaged, shown in FIG. 5, so that the key is rotationally coupled to the adjusting drive shaft 90. The drive shaft 90 is (by means not shown) rotated in a direction to produce retracting movement of the key 20. After the key has been thus backed off to produce a desired film thickness, the clutch is disengaged and this process is repeated for each of the keys in series. Since the amount of torque which may be transmitted through each of the clutches 70 (say, 15 in.-lbs.) is limited to a value which is substantially less than the reaction torque for which the collets have been adjusted (say, 30 in.-lbs.), any excess rotation of the clutch input element resulting in a bottoming of the stops 36, 40 in one direction or the other does not affect the reference phase adjustment of the stop 36. After bottoming occurs at the stop idle slippage will simply take place within the clutch thereby preventing the blade from moving either into jamming engagement with the surface of the roller or to a position which is so separated from the roller as to risk leakage of ink. However, the keys 20 may be adjusted frequently within the "single turn" range of adjustment provided by the stops as necessary to change the amount of ink fed at each key, or column, position along the length of the blade. Alternatively the keys may be adjusted by hand by a wrench W within the range of adjustment and with only light torque being applied.

After the fountain has been in use for a period of time, the edge 13 of the blade may be subject to wear because of the inherently abrasive characteristics of the ink. Where this occurs it is a simple matter to reestablish the reference condition of minimum blade clearance. Referring to FIG. 6 a wrench W if fitted to the outer end of the key and rotated to bring the stops 36,40 into bottoming engagement. A shim S is then inserted between the blade and roller at the key position, following which the wrench W is rotated an incremental amount resulting in slippage of the shank of the key with respect to the collet as the key is rotated in the advancing direction. When drag is felt upon the shim, the blade adjustment is complete and the wrench may be removed. The pointer 51, which is frictionally mounted upon the collet, is then restored to its reference zero position on the calibrated scale 62. This process is repeated at each key position. It will be apparent that minimum clearance may be reestablished quickly by incremental overpowering movement of the keys without going to the trouble of loosening up the entire system. When loosening of the collets becomes necessary, this can be done by rotating the wrench in the opposite direction, accompanied by bottoming of the stops 36,40 in the opposite direction.

The term "tool fitting" used herein in referring to the presented portion 24 of each key is not intended to be limited to any particular shape but includes any convenient termination which permits sufficient purchase for application of overpowering torque. The term "collet" as used herein refers to a sleeve engaging the shank of the key which includes means for applying inward squeezing pressure for development of friction at the engaged surfaces.

Claims

What we claim is:

1. In an ink fountain the combination comprising a frame mounting a rotatable fountain roller, a fountain blade on the frame having its edge cooperating with the roller a plurality of keys spaced evenly along the blade for adjusting the thickness of a film of ink deposited on the roller, each key having a shank threaded into the frame with a blade-engaging tip at its inner end and a presented outer end, a collet adjacent the outer end, the collet including a longitudinally slotted inner collar snugly telescoped on the shank, a radial stop on the inner collar, a fixed stop on the frame in the path of movement of the radial stop, the collet further including an outer collar threaded over the inner collar to establish a predetermined level of frictional reaction torque so that the key may be turned in the advancing direction with the stops in engagement to establish a condition of minimum clearance between the blade and the roller following which the key may be rotated over substantially a single revolution in the retract direction to establish a running clearance for the production of an ink film of predetermined thickness, the presented outer end of the key having a tool fitting for attachment of a tool for forcible rotation of the key in the advancing direction beyond the point of bottoming of the stops for periodic takeup for wear occurring at the edge of the blade.

2. In an ink fountain the combination comprising a frame mounting a rotatable fountain roller, a fountain blade on the frame extending along the roller and having its edge cooperating therewith, a plurality of keys spaced evenly along the blade for adjusting the thickness of a film of ink deposited on the roller, each key having a shank threaded into the frame with a blade-engaging tip at its inner end and having an outer presented end, a fixed stop on the frame, a cooperating radial stop on the shank of the key to define, upon bottoming, a condition of minimum clearance between the blade and the roller, an electric clutch surrounding the shank having an output element keyed to the shank and having an input element with means for rotating the input element, a first frictional coupling interposed between the radial stop and the shank and a frictional drive coupling interposed between input and output elements of the clutch, means for setting the friction in the first frictional coupling so that the reactive torque substantially exceeds the reaction torque of the frictional drive coupling so that when the radial stop bottoms on the fixed stop slippage takes place at the frictional drive coupling thereby preserving the phase condition between the radial stop and the key.

3. The combination as claimed in claim 2 in which a tool fitting is provided on the presented outer end of the key for forcibly turning the key in the advancing direction with the stops in engagement for overpowering the first friction connection for periodically reestablishing the condition of minimum clearance between the blade and the roller.

4. The combination as claimed in claim 3 including a longitudinally extending panel having apertures registering with the presented ends of the keys, the presented ends of the keys having pointers frictionally secured thereon for indicating the position of the radial stop, the panel having calibrated scales surrounding the apertures for cooperation with the respective pointers.

5. In an ink fountain the combination comprising a frame mounting a rotatable fountain roller, a fountain blade on the frame having its edge cooperating with the roller, a plurality of keys spaced evenly along the blade for adjusting the thickness of ink film deposited on the roller, each key having a shank threaded into the frame with a blade-engaging tip at its inner end and a presented outer end, an electric clutch of annular shape telescoped over the shank and having an output element secured to the shank and an input element including a sleeve extending along the shank and terminating in a drive gear, a reversible drive shaft for cooperating with the gears of all of the keys for simultaneous driving of the gears so that when one of the clutches is energized the corresponding key is adjustably rotated, a collet telescoped over the shank of each key at its outer end and in frictional engagement with it, a radial stop on the collet, a fixed stop on the frame in the path of the radial stop for defining the range of rotational adjusting movement of the key, and a tool fitting at the outer end of the key for enabling forcible turning of the key in the advancing direction with the stops in engagement to overcome the reaction torque of the collet thereby to establish a limit condition of minimum clearance between the blade and the roller.