US3497208A - Gripper actuator and control for sheetfed rotary printing presses - Google Patents

Description

GRIPPER ACTUATOR AND CONTROL FOR SHEET-FED ROTARY PRINTING PRESSES Filed March 4, 1968 Feb. 24, 1970 RElNARTZ ET AL 3,497,208

F/Gl. 38 37 FIG. 2. 20

25 4' INVENTORS Robekb Reinmrbz Henmann FisnheR OsKcm monqenlnndek United States Patent 3,497,208 GRIPPER ACTUATOR AND CONTROL FOR SHEET- FED ROTARY PRINTING PRESSES Robert Reinartz, Hermann Fischer, and Oskar Morgenlander, Augsburg, Germany, assignors to Maschinenfabrik Augsburg-Nurnberg AG, Augsburg, Germany, a corporation of Germany Filed Mar. 4, 1968, Ser. No. 710,106 Claims priority, application Germany, Mar. 4, 1967,

Int. Cl. B65h 29/06 US. Cl. 271-82 10 Claims ABSTRACT OF THE DISCLOSURE Actuating and control devices are provided for opening and closing the sheet grippers on the various rolls or cylinders or sheet-fed rotary printing presses and operated from only one side of the press, instead of having duplicate apparatus on both sides, yet in a manner which avoids non-uniform operation of the grippers frequently occurring from twisting moments in the gripper shaft if it extends entirely across the press but is rotated from only one end of the shaft. For this purpose, a plurality of separate gripper shafts, each short enough to avoid such twisting moments, are mounted across the press, instead of having a single shaft all the way across the press; and an intermediate or control shaft, also short enough to avoid such twisting moments, extends only partly across the press and parallel to the gripper shafts, which are linked to the control shaft so that rotation of the control shaft from only one end thereof will cause rotation of all the separate gripper shafts to open and close the grippers.

This invention relates to the actuation and control of sheet grippers on the various cylinders or rolls of sheetfed rotary printing presses for the uniform opening and closing thereof in timed relation with rotation of the include one or more rotating impression cylinders, each of which may be preceded and/or followed by one or more feeding or intermediate rolls or cylinders. In order to feed a sheet of paper or other material to be printed through the train of rotating cylinders, the various cylinders have a plurality of sheet grippers axially spaced and aligned at the surface thereof to grip and hold the leading edge of the sheet and to position the sheet in proper axial and circumferential location on the cylinder for the sheet to receive the printing impression in correct position and register.

Also, as will be understood, such sheet grippers are conventionally finger-like devices extending radially from a rotatable gripper shaft mounted along and carried by the cylinder in such manner that rotating the gripper shaft a few degrees in one direction will raise the gripper finger to receive or release a sheet, while rotating the gripper shaft in the opposite direction lowers the gripper finger to grip the edge of the sheet against a stationary member of the mechanism beneath the sheet. Since the thickness of the particular paper or other material being printed may vary substantially from one press run to another, means are conventionally provided for adjusting the extent of opening and closing movement of the gripper finger to accommodate sheets of various thicknesses.

Moreover, some arrangement is required for actuating opening and closing movements of the grip er fingers in timed relation with rotation of theprinting press cylinder on which they are mounted to receive, grip, and release each successive sheet at the proper moment, and, since the gripper mechanism is on and carried by the rotating cylinder, such means are conventionally located at the ends of the cylinders accessible from the side of the press.

Particularly with modern large and high speed printing presses, it is important that the plurality of axially aligned grippers spaced along the rotating cylinder operate with extreme uniformity regarding timing, extent of opening, and gripping pressure, in order correctly to receive each successive sheet and position and hold it properly on the cylinder. Nevertheless, the entire mass of the gripper mechanism and shafts and brackets, etc., must be carried by the rotating cylinder and is eccentrically located therein, so that such mass is desired to be kept as small as practicable.

Especially with large printing presses, it may be found that a rotatable gripper shaft of a practical diameter and weight, which extends clear along the press cylinder and clear across the press, may develop or permit enough twisting within the shaft so that uniform gripping is not obtained by the various grippers spaced along the entire length of the cylinder if the gripper shaft is rotated by operating mechanism at only one end thereof. Attempting to compensate for such twisting by adjusting the angular position of the individual grippers on the gripper shaft is extremely time-consuming and to an extent which may not be considered economically practical, even if accurate uniformity could actually be achieved by such manual adjustment,

Similarly, if it is attempted to eliminate the foregoing disadvantage by providing two separate gripper shafts, each extending over only half the length of the cylinder (so that each is short enough to avoid the twisting difficulty), Separate operating mechanisms must be provided for each of the gripper shafts (e.g., at opposite sides of the printing press). In addition to the undesired additional expense required for providing such duplicate operating mechanisms, tremendous difficulty may be experienced in attempting to adjust the separate operating mechanisms in complete synchronization so that all of the grippers on both separate shafts operate together and with complete uniformity of movement and pressure regarding both the timing and extent of opening as may be required with each different press run.

According to this invention, by contrast, a plurality of gripper shafts is provided and mounted in the printing press cylinder in axial alignment with each other, each gripper shaft extending for only a portion of the entire length of the cylinder and being short enough so that any twisting distortion is sufficiently small to be negligible; and additionally providing. a control shaft system extending parallel to the gripper shafts, but only part way along the entire length of the cylinder and being short enough to avoid twisting distortions. The operating mechanism at only one end of the cylinder is connected at one end of the control shaft is transmitted individually to the separate gripper shafts by linkages between each gripper shaft and the control shaft. As a further feature of this invention, means for adjusting both the extent of opening of the grippers and the angular timing thereof are incorporated in the operating mechanism effective upon the control shaft and at only one side of the printing press.

With the foregoing and additional objects in view, this invention will now be described in more detail, and other objects and advantages thereof will be apparent from the following description, the accompanying drawing, and the appended claims.

In the drawing:

FIG. 1 is a partial plan view of apparatus embodying and for practicing this invention as mounted in a printing press cylinder, the outer shell of which has been removed for clarity; and

FIG. 2 is a plan view of the arrangement of FIG. 1 from one end of the cylinder and in a direction indicated by the arrow A in FIG. 1.

Referring to the drawings, in which like reference characters refer to like parts throughout the several views thereof, an impression cylinder of a sheet-fed rotary printing press is indicated generally at 10, as mounted on a shaft 11 for rotation in the printing press and as having an outer shell 12 providing a circumferential surface over which a sheet of paper or other material to be printed is to be carried. A plurality of sheet grippers 1-5 are shown as axially aligned and spaced along cylinder for receiving and gripping the leading edge of the sheet to draw it around the cylinders to overlie outer shell 12 when the cylinder is rotated in the direction indicated by the arrow in FIG. 2.

As will be apparent, FIG. 1 shows only a portion of the entire length of cylinder 10 and shaft 11, but, in the illustrative embodiment here depicted, the longitudinal center line of the printing press and the mid-point of the axis of cylinder 10 are indicated by the line .B in FIG. 1. As will be understood, the opposite ends of shaft 11 are conventionally mounted in the main frame of the printing press (not shown) for rotation of cylinder 10 as operatively connected to the main printing press drive means, all in known and well understood manner.

Grippers 15 (only three of which are shown but more would be used axially spaced along cylinder 10) are affixed to and carried by a gripper shaft. In the illustrated embodiment, two such gripper shafts and 21 are shown, each extending substantially half way along the length of cylinder 10. Gripper shaft 20, for example, is mounted for rotation with the end nearest the side of the press being rotatably supported in bearing 22 mounted on a bracket 23 carried by shaft 11, while the other end of gripper shaft 20 nearest the center of the press is rotatably mounted in bearing 24 mounted on a bracket 25, also carried by shaft 11. Bearing 24 is really a double arrangement which also supports the innermost end of the other gripper shaft 21, the opposite end of which is supported similarly to the outside end of shaft 20 as by an arrangement (not shown) like bearing 22 and bracket 23. The lengths of gripper shafts 20 and 21, and, of course, the spacing between brackets 23 and 25, are deliberately selected, for the desired diameters and characteristics of gripper shafts 20 and 21, to be short enough to avoid twisting of the gripper shafts under conditions of actual operation and for whatever desired gripping pressure or twisting moments of force may be imparted to shafts 20 and 21 by the various grippers 15 spaced therealong.

Also supported rotatably in brackets 23 and 25 is control shaft 30, extending substantially parallel to gripper shaft 20 from beyond the right-hand end of cylinder 10 to a point just sufficiently to the left ofthe end of gripper shaft 21 in FIG. 1 to permit the linkage coupling therebetween described below. The length of control shaft 30, as with gripper shafts 20 and 21, is also selected to be short enough to avoid twisting deformations in use When control shaft 30 is rotated by operating mechanism (described below) at only the extreme right-hand end thereof. Near that end of control shaft 30 which is carried by bracket 25 at the center of the printing press are afiixed two double- arm levers 31 and 32, one arm of each of which is connected to, respectively, levers 35 and 36 radially extending from, respectively, gripper shafts 20 and 21, such connecting being by means of rigid links 37 and 38 (part of each of which is broken away for clarity in FIG. 1) extending, respectively, between lever arms 31 and 35 and between lever arms 32 and 36. The other arms of levers 31 and 32 on control shaft 30* are engaged, in known manner, by compression springs 40 and 41, respectively, so as to urge levers 31 and 32 in a direction (toward the right in FIG. 2) to rotate control rod 30 counterclockwise in FIG. 2, and, thus, minimize play in the linkages and act to bias the return of the cam and cam follower operating mechanism described below for rotating control shaft 30.

As will be apparent from the foregoing, the arrangement just described provides for as large a plurality as may be desired of grippers 15 spaced along cylinder 10 and carried by two rotatable gripper shafts 20 and 21, each of which extends only over about half the length of cylinder 10, and, thus, can be free of any twisting deformations under pressure. Similarly, control shaft 30 is short enough to be free of such twisting deformations because it extends over only a little more than half the length of cylinder 10 and just sufficiently to be connected by the linkage indicated with the ring-hand end of gripper shaft 21. Similarly, the connection of one arm of levers 31 and 32 radially extending from control shaft 30 with, respectively, lever arms 35 and 36 radially extending from gripper shafts 20 and 21 by means of links 37 and 38 provides for rotating gripper shafts 20 and 21 uniformly and together upon rotation of control shaft 30.

In this manner, once the angular positions of grippers 15, lever arms 35 and 36, and levers 31 and 32 have been uniformly established and fixed with respect to gripper shafts 20' and 21 and control shaft 30, no further adjustment need be made and uniform operation of the whole plurality of grippers 15 along gripper shafts 20 and 21 will be assured, upon rotation of control shaft 30, because none of the shafts is long enough to develop or permit twisting deformations which might, on a longer shaft rotated from only one end thereof, produce nonuniform gripping or pressure by grippers 15.

In the illustrated embodiment, the operating mechanism for rotating control shaft 30 (and, upon rotation thereof, producing rotation of gripper shafts 20 and 21 in one direction or the other to accomplish opening and closing of grippers 15) may now be described. At that end of control shaft 30 which extends beyond the end of cylinder 10 (the right-hand end in FIG. 1) there is keyed a collar having a radially extending arm 46. Next to collar 45 there is mounted on control shaft 30, but rotatable with respect thereto, a two-arm actuating lever 48, having one radially extending arm 49 adjacent arm 46 of collar 45 and in abutting engagement therewith through adjustment screw 50. The other radially extending arm of actuating lever 48 carries roller forming a cam follower for engaging a stationary cam 56 mounted on a stationary portion of the main printing press frame (not shown) and, preferably, in a manner such that the angular positioning of cam 56 can be adjusted within certain limits (e.g., as by providing slots 57 through which cam 56 is fixed into the desired stationary position thereof by set screws, all in known manner).

As will be apparent from the foregoing, the arrangement just described provides for the rotation or angular movement of control shaft 30 one way or the other as cylinder rotates during operation of the printing press. That is, as cylinder 10 rotates with respect to stationary cam 56, roller 55 will follow the cam surface and, upon reaching the eccentric elevation thereof, will be moved radially outwardly with respect to cylinder 10, thus rotating actuating lever 48 in a manner so that arm 49 thereof, through adjusting screw 50, will bear upon arm 46 of collar 45 and rotate control lever 30 in a direction and to an extent effecting a similar rotation of gripper shafts 20 and 21 (through the lever linkages 31-38 described above), eflFecting closing of grippers into gripping position. When roller 55 leaves the extended surface of cam 56, grippers 15 will be opened as rotation of control shaft 30 in the opposite direction (under the urging of spring mechanism 40 and 41) rotates gripper shafts and 21 to open grippers 15.

Furthermore, by adjusting adjustment screw 50 to different positions, the circumferential distance between radially extending arms 46 and 49 on collar 45 and actuating lever 48 is altered and adjusted to define the extent of opening of grippers 15 produced by the operating mechanism to accommodate different thicknesses of sheets to be printed, while the provision of slots 57 (or equivalent means) for adjusting the angular positioning of stationary cam 56 provides for controlling the particular angular positions of rotating cylinder 10 at which grippers 15 will open and close.

As will be apparent from the foregoing, means and arrangements are provided in accordance herewith for mounting a plurality of sheet grippers along the rotating impression or other cylinders of a sheet-fed rotary printing press on a plurality of rotatable gripper shafts, in a manner so that each is free of twisting deformations although rotation is accomplished at only one end of each gripper shaft, and implementing the foregoing by utilizing a separate control shaft mounted parallel to the gripper shaft, but itself being short enough to avoid such twisting deformations and extending only part way along the cylinder length, but far enough to permit a lever linkage interconnection with each of the gripper shafts. Similarly, operating means for actuating the control shaft and, through the lever linkages, 'each of the separate gripper shafts, is provided at the outer and accessible end of the control shaft in a manner which includes readily accessible adjustments for both the extent of opening of the various grippers and the angular position of the cylinder at which they all open and close.

In this manner, virtually complete uniformity of timing, extent of gripper opening, and gripper pressure on the sheets to be printed is assured all along the whole length of the printing press cylinder, despite the frequent need for adjusting the gripper opening to accommodate different thicknesses of sheets in different press runs. All the foregoing is readily accomplished in accordance herewith utilizing relatively inexpensive apparatus which can be produced economically, and which substantially reduces the labor time which must be spent in adjusting the grippers for each press run and/or correcting maladjustments thereof, particularly since such adjustments need be made only at one side of the printing press in the single operating mechanism there provided for operation of all the grippers on a particular printing press cylinder.

While the arrangements and forms of apparatus described herein form preferred embodiments of this invention, it is not limited to these precise arrangements and forms of apparatus, and changes may be made therein without departing from the scope of this invention.

What is claimed is:

1. In apparatus of the character described for actuating and controlling uniformly the timing and extent of opening and closing of a plurality of sheet grippers axially spaced and aligned along a rotating cylinder of a sheet-fed rotary printing press for uniformly gripping and holding the leading edge of sheet material to be printed on said printing press during passage of said sheet material over said rotating cylinder, the combination which comprises a plurality of sheet grippers axially spaced and aligned substantially throughout the entire axial extent of said rotating cylinder for receiving and gripping and releasing said leading edge of said sheet material upon sequential opening and closing of said sheet grippers during rotation of said rotating cylinder, a plurality of gripper shafts coaxially aligned along said cylinder for carrying said sheet grippers and for effecting opening and closing thereof upon rotation of said gripper shafts in one direction or the other, each of said coaxially aligned gripper shafts extending over a portion on y of the entire axial extent of said rotating cylinder whereby the length of each separate said gripper shaft is less than that producing twisting distortions effecting non-uniform operation of said grippers upon rotation of each said gripper shaft at only one end thereof, bearing means for rotatably mounting each of said separate gripper shafts coaxially along said cylinder, a control shaft extending parallel to said gripper shafts and from one end of said cylinder only partially along the full axial extent thereof to a point adjacent the innermost end of the one of said plurality of gripper shafts furthest actually axially removed from said end of said cylinder, the length of said control shaft being less than that producing twisting distortions upon rotation of said control shaft from only one end thereof, means for mounting said control shaft for rotation in said cylinder and parallel to said gripper shafts, lever linkage means for interconnecting at least one end of each of said separate gripper shafts with said control shaft for rotation of all said gripper shafts uniformly upon rotation of said control shaft, and operating means at said end of said cylinder effecting intermittent rotation of said control shaft in either direction upon rotation of said cylinder and in timed relation therewith for opening and closing said sheet grippers at predetermined angular positions of said rotating cylinder during operation of said printing press for periodic receiving and gripping and releasing of a sheet to be printed.

2. Apparatus as recited in claim 1 in which said operating means at said end of said cylinder also includes means for adjusting the radial extent of opening and closing of said sheet grippers for accommodating various thicknesses of said sheet material to be gripped thereby.

3. Apparatus as recited in claim 1 in which said operating means at said end of said cylinder also includes means for adjusting the angular positions of said rotating cylinder at which said sheet grippers receive, grip, and release said sheet material.

4. Apparatus as recited in claim 1 in which said lever linkages interconnecting said plurality of gripper shafts with said control shaft include lever arms radially extending from each of said shafts and rigid links interconnecting respectively said radially extending arms of said gripper shafts with those on said control shaft for direct and uniform rotation of all said gripper shafts upon rotation of said control shaft.

5. Apparatus as recited in claim 1 which also includes biasing means effective upon said control shaft for urging said control shaft in a direction of rotation opposite to the direction effected by said operating means at said end of said cylinder.

6. Apparatus as recited in claim 1 which includes two coaxial gripper shafts each extending substantially half way along said rotating cylinder, bracket means for ro tatably mounting said two gripper shafts at the opposite ends thereof coaxially along said cylinder, two of which bracket means also include said means for mounting said control shaft parallel to said gripper shafts in said cylinder.

7. Apparatus as recited in claim 6 in which said cylinder is a hollow shell carried by a central shaft and in which said bracket means for carrying said plurality of gripper shafts and said control shaft are mounted on said central shaft of said cylinder.

8. Apparatus as recited in claim 1 in which said operating means at said end of said cylinder effecting rotation of said control shaft and opening and closing of said sheet grippers includes a cam surface, means for mounting said cam surface on said printing press as stationary with respect to said rotating cylinder, a cam follower operatively connected with said control shaft for rotation thereof in either direction as said cam follower follows said cam surface for defining the angular positions of said rotating cylinder at which said sheet grippers receive, grip, and release said sheet material during rotation of said cylinder.

9. Apparatus as recited in claim 8 in which said opera tive connection of said cam follower to said control shaft includes adjusting means for adjusting and defining the radial extent of opening and closing of said sheet grippers as said control shaft is rotated by the interaction of said cam surface and said cam follower.

References Cited UNITED STATES PATENTS 2,892,630 6/1959 Schunemann 27182 GERALD M. FORLENZA, Primary Examiner ROBERT J. SPAR, Assistant Examiner US. Cl. X.R. 198-2l0

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