US3913479A

US3913479A - Ink fountain having a continuous metering bar with zonal adjustment

Info

Publication number: US3913479A
Application number: US551630A
Authority: US
Inventors: Bert Cappel; Siegfried Schuhmann; Klaus Wolf
Original assignee: Roland Offsetmaschinenfabrik Faber and Schleicher AG
Current assignee: Roland Offsetmaschinenfabrik Faber and Schleicher AG
Priority date: 1973-06-20
Filing date: 1975-02-21
Publication date: 1975-10-21
Anticipated expiration: 1992-10-21

Abstract

An ink fountain having a metering bar in the form of a continuous strip of tough resilient material, the bar being recessed in a slot formed in the frame with only its presented edge exposed and abutting the fountain roller. The metering bar is adjusted by a series of adjusting mechanisms with respective grippers uniformly spaced along the rear edge of the strip to define zones of adjustment, with the rear edge of the strip being deeply relieved between the adjacent grippers to form intermediate regions of reduced cross section so as to provide localied flexibility to permit relative independent zonal movement of the adjusting mechanisms for localized metering of the ink film. In the disclosed embodiment each gripper has a plunger which is reciprocated through a narrow range by a motor driven cam and cam follower, each plunger having provision for length adjustment and each plunger having a return spring to maintain the cam follower seated on the cam.

Description

United States Patent Cappel et al.

INK FOUNTAIN HAVING A CONTINUOUS METERING BAR WITH ZONAL ADJUSTMENT Assignee:

Filed:

Appl. No; 551,630

Inventors: Bert Cappel, Offenbach-Bieber;

Siegfried Schuhmann, Offenbach; Klaus Wolf, Neu-lsenburg, all of Germany Roland Offsetmaschinentabrik Faber & Schleicher AG, Germany Feb. 21, 1975 Related US. Application Data Oct. 21, 1975 Primary Examiner-14 Reed Fisher Attorney, Agenl, 0r FirmWolfe, Hubbard, Leydig, Voit & Osann, Ltd

[57] ABSTRACT An ink fountain having a metering bar in the form of a continuous strip of tough resilient material, the bar being recessed in a slot formed in the frame with only its presented edge exposed and abutting the fountain roller. The metering bar is adjusted by a series of ad justing mechanisms with respective grippers uniformly spaced along the rear edge of the strip to define zones of adjustment, with the rear edge of the strip being deeply relieved between the adjacent grippers to forrr intermediate regions of reduced cross section so as It provide localied flexibility to permit relative indepen dent zonal movement of the adjusting mechanisms fox localized metering of the ink film. In the disclosed em bodiment each gripper has a plunger which is recipro cated through a narrow range by a motor driven can and cam follower, each plunger having provision foi length adjustment and each plunger having a returr spring to maintain the cam follower seated on the cam.

10 Claims, 3 Drawing Figures US. Patent Oct. 21, 1975 3,913,479

INK FOUNTAIN HAVING A CONTINUOUS METERING BAR WITH ZONAL ADJUSTMENT This application is a continuation-in-part of our US. application, Ser. No. 371,594, filed On June 20, 1973.

It is an object of the present invention to provide an ink fountain which employs an ink metering bar in the form of a continuous strip of tough flexible material in abutting relation to the fountain roller, the strip being provided with a series of grippers with relief between adjacent grippers to define adjustable sections separate by intermediate regions of localized flexibility, and with each of the adjustable sections having an adjusting mechanism to provide an ink film which is continuous along the fountain roller but which enables accurate and independent metering of film thickness in closely spaced zones of adjustment.

It is a further object to provide an ink fountain which permits column by column adjustment of ink flow by means of independently adjustable sections but which avoids the leakage problems generally associated with sectional adjustment.

It is a related object to provide an ink fountain having a metering strip for metering a film of ink which is continuous along the length of the fountain roller but which is subject to a wide variation in adjustment between adjacent zonal sections thereby to permit wide variations in the rate at which ink is furnished to adjacent column positions on the printed sheet.

lt is another object of the present invention to provide a sectioned metering bar having a presented edge of which only the presented edge portion is in contact with the ink and which avoids slideability between the sections so that each of the sections of the bar may be adjusted reliably using relatively low adjusting forces in spite of accumulation of dried or gummy ink.

It is yet another object of the invention to provide a metering type ink fountain which may be inexpensively constructed, which includes a plurality of adjusting mechanisms having individual adjusting motors of low power capability, and which is capable of operating for long periods substantially free of maintenance problems.

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

FIG. 1 is a vertical section taken through an ink fountain embodying the present invention.

FIG. 2 is a fragmentary plan view of the metering bar used in the structure of FIG. I and looking along the line 2-2 therein.

FIG. 3 is a fragmentary perspective showing a typical adjusting linkage used in the device of FIG. 1.

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

Turning now to FIG. I there is shown an ink fountain having a frame 70 which includes an upper trough portion 71 and a lower, or base, portion 72. The portions are hinged together for relative movement about a hinge axis 73. The two portions, together, define a horizontal slot 74. Fitted snugly in the slot is a metering bar having a presented edge, or tip, 76 which abuts against the surface 77 of a fountain roller 78, the plane of the metering bar preferably falling close to the axis 79 of the roller.

The trough portion 71 includes a body of ink indicated at 1. When the fountain roller is rotated in the direction shown, so that the surface 77 passes downwardly through the body of ink, a film of ink is established on the fountain roller which depends upon the clearance between the metering bar and the roller surface.

In accordance with the present invention the metering bar 75 is in the form of a continuous strip of tough resilient material having parallel side walls snugly fitted in the horizontal slot and with a plurality of adjusting mechanisms, including respective grippers uniformly spaced along the rear edge of the strip to establish adjustable sections defining a series of zones of adjustment, the rear edge of the strip being deeply relieved between adjacent grippers to form intermediate regions of reduced cross section with the resulting flexibility permitting independent relative movement of the adjusting mechanisms and localized control of the ink film in the respective zones.

Turning to FIGS. 2 and 3, the metering bar 75 consists of spaced adjustable sections 80, preferably corresponding to column positions, with relief between the sections in the form of notches 81 defining narrow bridges of resilient material as indicated at 82 between the adjustable sections. The metering bar is of generally rectangular cross section presenting a flat upper face 85 and a flat lower face 86 parallel thereto which engage the upper and lower walls of the slot 74 in the frame structure. To provide additional insurance against leakage of ink along the metering bar, the walls of the frame members are longitudinally relieved to form opposed grooves which are occupied by strips of resilient sealing material indicated at 87, 88.

The notches 81 are relatively narrow compared to the adjustable sections 80 and are quite deep, penetrating into the strip a distance which is the major portion of the width of the strip. The roots of the notches are of smoothly arcuate profile so that the bridges 82 of reduced cross section produce a gradual transition from one adjustable section to the next so that the sections may be differentially adjusted with avoidance of any sharply defined shear plane, or region of concentrated stress, between them.

For the purpose of moving each of the sections 80 toward and away from the fountain roller to adjust the film thickness, a connecting linkage 90 is provided having a gripper 91 of C" cross section having lips regis tering with longitudinal grooves formed on the upper and lower surfaces of the strip. Each gripper is permanently secured to a plunger 92 which is screwed into a bushing 93. Screwed into the opposite end of the bushing, with a differential or opposite thread, is a plunger portion 94 connected to a clevis 95. The clevis has a pin 96 which mounts an anti-friction bearing 97, the surface of the bearing serving as a cam follower surface 98.

For positioning the cam follower surface, a cam 100 is provided having a slightly eccentric surface, the cam being mounted upon a drive shaft 101 connected to a gear box 102 driven by a remotely controlled, reversible, electric drive motor 103. For maintaining the cam follower surface solidly bottomed, at all times, against the surface of the cam 100, a strong return, or biasing, spring is provided which is preferably in the form of a stack of cupped spring (Bellville) washers S interposed between the bushing 93 and the frame.

It will be apparent, then, that when the high of the cam is crowded against the cam follower surface 98, the linkage 90 is translated outwardly, advancing the associated section 80 of the metering bar toward the fountain roller to reduce the film thickness. When the cam is rotated by the motor to its low position, the spring washers 105 are free to expand causing the section of the metering bar to be retracted from the fountain roller to increase the film thickness. This process is repeated for each column position for metering of the ink in accordance with the amount required in each column position. For the purpose of establishing a reference condition for all of a plurality of linkages 90, the plungers 94 may be screwed in and out of the bushings which they engage and with the adjusted position being preserved by a set screw or the like in each bushing.

It will also be apparent that while it is preferred to employ individual adjusting motors 103 to effect zonal adjustment of the ink film, the invention is not limited thereto and the cams 100 may be provided, if desired, with manual adjusting means and with scales calibrated in terms of film thickness to achieve reproducible settings.

The invention is not limited to use of any particular tough resilient material for the metering bar 75. Many different plastics and synthetic rubbers are selectively available having a durometer rating between 70(A) and 90(D) and which combine the features of toughness, flexibility, and dimensional stability in the presence of the various inks and solvents which may be used in a practical press and having characteristics which remain instant in spite of the passage of time. The plastic material which is sold by the Bayer organi' zation under the trademark VOLKOLLAN is, however, preferred.

Only a very narrow tip portion of the strip is exposed, namely, that portion immediately adjacent the presented edge 76 so that there is little or no accumulation ofdried or gummy ink. Since the sections are resiliently joined, the cementing of adjacent sections, which tends to occur when separate relatively slideable sections are employed, cannot occur. Because of the positive push-pull operation of the gripper 90, combined with the high degree of mechanical advantage of the cam, precise and consistent setting is assured using only low power motors. The power requirement is further reduced by the fact that the metering strip is of limited width dimension, and deeply notched, so that only a limited area is in contact within the slot 74 to produce a snug fit and effective seal against leakage while nevertheless reducing the frictional forces which must be overcome when making an adjustment.

lt will be apparent that the above described embodiment amply carries out the objects of the invention providing a structure which enables zonal metering of ink with smooth transition of ink thickness between zones, which may be adjusted with a high degree of precision and reproducibility, which is capable of operating over long periods of time without maintenance or readjustment and which is inherently economical for use on new presses as well as use, for replacement purposes, on presses which are already in the field. The term gripper as used herein is a general term covering any means providing localized connection between a section of the strip and its associated adjusting means.

What is claimed is:

1. In an ink fountain the combination comprising a frame defining a horizontal slot having parallel walls, a fountain roller rotatable in the frame adjacent the slot, a metering bar mounted in the slot and having a presented edge arranged in abutting relation with the surface of the roller, the frame being shaped to support a body of ink adjacent the metering bar so that a film of ink is formed on the roller by the bar as the roller is rotated, the metering bar being in the form of a continuous strip of tough resilient material having parallel side walls snugly fitted in the horizontal slot with only the presented edge portion extending therefrom, a plurality of adjusting mechanisms including respective grippers uniformly spaced along the rear edge of the strip to establish adjustable sections defining a series of zones of adjustment, the rear edge of the strip being deeply notched between adjacent grippers to form intermediate regions of reduced cross section so as to provide 10- calized flexibility to permit independent relative movement of the adjusting mechanisms and localized metering of the ink film in the respective zones.

2. The combination as claimed in claim 1 in which each adjusting mechanism includes a plunger and cam follower, a rotatable cam for operating on the cam follower, and a spring interposed between the frame and the plunger for maintaining the cam follower bottomed on the cam.

3. The combination as claimed in claim 1 in which each gripper has a plunger which extends rearwardly at right angles to the strip and in which each plunger has means including a cam and cam follower for adjusting the position of the gripper and the corresponding section of the strip with respect to the frame and fountain roller.

4. The combination as claimed in claim 1 in which the strip has flat parallel sides and in which each of the grippers is of "C" cross section for gripping a corresponding portion of the rear edge of the strip.

5. The combination as claimed in claim 1 in which each mechanism includes a plunger secured to the gripper, means including a motor driven cam and cam follower at the end of the plunger for positioning the gripper and the corresponding portion of the strip with respect to the fountain roller, and means for adjusting the effective length of the plunger to establish a reference condition.

6. The combination as claimed in claim I in which the regions of reduced cross section are of arcuate profile to provide smooth transition between adjacent adjustable sections and are sufficiently flexible as to enable a large disparity in the adjustment of the adjacent sections free of concentration of stress.

7. The combination as claimed in claim 1 in which the notches have substantially parallel sides with smoothly arcuate roots and are of a dimension, longitudinally of the strip, which is only a minor fraction of the dimension of the adjustable sections.

8. The combination as claimed in claim 7 in which each notch extends inwardly of the strip a distance which is the major portion of the width of the strip.

9. The combination as claimed in claim 3 in which individual motors are provided for individual zonal adjustment of the adjustable sections.

10. The combination as claimed in claim 1 in which the walls of the slot are longitudinally relieved to form opposed grooves and in which the grooves thus formed are occupied by resilient sealing material, thereby to preclude leakage of ink between the metering strip and the walls of the slot.

i 4 i l

Claims

1. In an ink fountain the combination comprising a frame defining a horizontal slot having parallel walls, a fountain roller rotatable in the frame adjacent the slot, a metering bar mounted in the slot and having a presented edge arranged in abutting relation with the surface of the roller, the frame being shaped to support a body of ink adjacent the metering bar so that a film of ink is formed on the roller by the bar as the roller is rotated, the metering bar being in the form of a continuous strip of tough resilient material having parallel side walls snugly fitted in the horizontal slot with only the presented edge portion extending therefrom, a plurality of adjusting mechanisms including respective grippers uniformly spaced along the rear edge of the strip to establish adjustable sections defining a series of zones of adjustment, the rear edge of the strip being deeply notched between adjacent grippers to form intermediate regions of reduced cross section so as to provide localized flexibility to permit independent relative movement of the adjusting mechanisms and localized metering of the ink film in the respective zones.

4. The combination as claimed in claim 1 in which the strip has flat parallel sides and in which each of the grippers is of ''''C'''' cross section for gripping a corresponding portion of the rear edge of the strip.

6. The combination as claimed in claim 1 in which the regions of reduced cross section are of arcuate profile to provide smooth transition between adjacent adjustable sections and are sufficiently flexible as to enable a large disparity in the adjustment of the adjacent sections free of concentration of stress.