US 1978715 A
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Description (OCR text may contain errors)
Oct. 30, 1934. 0. c. F. MEISEL 1,978,715
ROTARY WEB mass Filed Feb. -16. 195s 2 Sheets-Sheet 1 Oct. 30, 1934. o, c, F, MEISEL 1,978,715
ROTARY WEB PRESS Filed Feb. 16, 1933 2 Sheets-Sheet 2 Patented 0.1.30, 1934 UNITED STATES PATENT orrica 3 Claims.
This invention relates to rotary presses and the object" is to provide a'web press which will print on the web an immediate succession of impressions of less length than the circumference of the plate cylinder or cylinders. The web thus may be completely imprinted without waste and be cut into sheets of correspondingly short length, folded or otherwise disposed of as may be desired. I obtain this result by the use of a suitable looping mechanism which is readily adjustable to provide for the printing of different sized sheets.
My invention wlllbe well understood by reference to the following description of the illustrative embodiment thereof shown by way of example in the accompanying drawings, wherein:--
Fig. 1 is a diagram of the press;
Fig. 2 is a broken fragmentary view of the mechanism for operating the looper rolls; and
Fig. 3 is-a diagram corresponding to part of Fig. 1 and showing a modification.
Referring to Fig. 1 of the drawings, I have there shown a. rotary press embodying a plurality of printing couples comprising the plate cylinders 5 and impression cylinders 7. The web w drawn from a suitable supply is fed thereto by feed rolls 9 over fixed roll 11, movable looper roll 13 carried on the reciprocating frame 15, andflxed roll 17, leads thence through the printing couples, and leaves the latter over fixed roll 19, movable looper roll 21 carried by frame 15 in fixed relation to looper roll 13, fixed roll 23, and feed rolls 25 which operate in synchronism with'feed rolls 9.
The feed rolls 9 and 25 may be suitably driven,
as, for instance, by means of change gears to left in Fig. 1, roll 21 will draw through the couples slack released by the movement of. the roll 13 so as to permit the web to pass through the couples during the printing operation at the same surface speed as the form. After printing is finished and while the web is no longer gripped between the form cylinder and the impression cylinder, movement of the looper rolls to the left may be retarded. They may then be moved back to the right so that roll 13 draws back the web through the forms and also takes up the web which is meanwhile being supplied by the rolls 9 while roll 21 gives up slack to permit the retraction of the web through the forms and to permit the continued operation of the feed rolls 25, delivering the web from the press at a constant speed. At the end of this retrograde movement the looping rolls may move to the left once again, gradually accelerating the paper extending between them to the speed of the plate cylinder so that when the latter again starts to print, blank paper immediately behind the part previously printed is presented to the form.
Looping mechanism operating generally in the manner above described is disclosed in the patent to Annand 834,602, Oct. 30, 1906, and does not need extensive description. The arrangement there shown, however, requires the use of separate cams for operating the loopers for each sheet length printed and provides for advancing the sheet at a uniform speed by the joint action of the feed rolls and the looper rolls during such fraction of the revolution as is equal to a fraction whose numerator is the sheet length and whose denominator is the cylinder circumference. In contrast therewith I provide a single cam in connection with which an exceedingly simple adjustmizeent provides for handling a wide range of sheet s s.
I will first describe in a general way the mechanism shown without reference to its theory of operation. Herein the looper frame 15 (see Fig. 2) carries a rack 27 with which meshes a sector 29 operated by a pitman 31 which is oscillated by groove cam 33 which makes one revolution for each revolution of the press. The pitman 31 has an adjustable crank connection with the sector 29, the latter being here shown with a slot 35 along which the end of the pitman may be slidably adjusted to be clamped by the clamp screw 37.
In accordance with my invention 1 provide for a uniform advance of the web by the looper rolls during a fixed fraction of the revolution of the plate cylinders while the construction is such as to permit the handling of sheets of any length equal to or less than the product of this fraction and the cylinder circumference without changing the machine other than by a simple and readily made adjustment and the necessary change in speed of the feed rolls 9 and 25 to permit them to feed in and out the desired length of sheet.
By way of example and to illustrate one practical construction we may take as this fixed fraction of the circumference of the cylinder, the arrangements then permitting printing a sheet of this or any shorter length. I preferably provide an excess feeding movement to insure that no change of paper speed will occur while the web is gripped by the plate cylinder and for that reason may utilize 260 of the revolution for feeding the paper at the surface speed of the plate cylinders. This provides for 4 at either end which may be considered excess feed. The remaining 100 of a revolution may then be utilized to stop the sheet, to retract it and again to reverse its motion, and conveniently, as in the example herein chosen for illustration, 60 of the revolution may be utilized for retracting movement corresponding to a movement of the rolls 13 and 21 to the right in Fig. 1 and 40 to the reversals of movement suitably arranged to prevent shock.
Thus referring to the cam shown in Fig. 2 (the possibility of cutting such a cam will be shown by the analysis to follow later), the arc ab cd may be a smooth spiral corresponding to an advance of the looper rolls to the left at uniform speed. a-b, 4 in extent, represents an idle movement or overfeed before the plate cylinder begins to act. The are bc is 252 long and during this time printing takes place. Overfeed of 4 is provided at cd. I here show are de as 10 in extent. This period is utilized in reversing the rolls and may, if desired, provide for a retarded movement to the left and/ or preferably includes a substantial period of dwell at the extreme of movement to permit absorption of inertia. The are e---), 60 in length, provides for retracting the paper. Arc f--a, 30 in length, provides for reversal with the rolls moving to the right again preferably with a substantial dwell and, if desired, with subsequent acceleration to the left. Since the movement of the rolls to the left is slower than the movement to the right, are de may conveniently as here be shorter than are fa and the period of dwell may be shorter. It should be understood that on account of the small scale of the drawing it represents only in a very general way the cam contour.
The arrangement may be best understood by considering first the length of paper moved independently of speed. For convenience in the discussion we may denote the circumference of the plate cylinder as C and the length of paper or sheet length delivered by the rolls 9 and 25 as S. During the 260/360 of a revolution, therefore, the feed rolls deliver a length of paper equal to 260/360 S and, if it is desired to move this through the couples at the same linear speed as the surface speed of the plate cylinder, the length of paper passing through the couples must be 260/360 C. and the movement of looper roll 21 to the left must then draw through the couples a length of paper equal to 260/360 (CS). Similarly in any retarding movement previous to retraction of the web and while arc de of the cam is acting, the looper may draw paper equal in length to P at any suitable variable speed, and similarly if acceleration is provided in the arc fa the rolls may draw forward a length Q. The total excess movement due to the operation of the looper roll is therefore 260/360 (CS) +P+Q. The linear movement of the roll on the frame 15 due to the fact that it operates on the bight of a loop isone-half 01' this.
Now, referring to Fig. 2, if the throw of cam 33 is t and the pitch radius of segment 29 is 10 inches, the effective crank arm a: by means of which pitman 31 must act on the'segment deflning the position of connection 37 along slot 35 is determined by the following proportion:
10 i: Now for any given machine all these terms are constants except the sheet length S and for any value of S, that is, for any given sheet length, will correspond a value of :c, that is, a definite position of point of connection of the pitman to the sector which will provide for a proper advance of the looping rolls.
The description thus far has been primarily of the action of the'web during 260 of the revolution of the plate cylinder or 260 of the revolution of the cam 33 during the feeding action of the latter. The net desired result of the cooperating action of the feed rolls and the looper rolls is to pass through the couples a sheet length S on each revolution. There passes forward through the couples during the advancing feed a length of web equal to 260/360 C. The sheet length S has been usefully utilized to receive an impression. We must draw back 260/360 CS. During the remaining 100 of the circumference, if any deceleration or acceleration is provided while the loopers still move to the right, the length P-i-Q is drawn through. Moreover, during this 100/ 360 of a revolution the feed rolls 9 will deliver 100/360 S. We must draw back, therefore, the sum of these quantities, which is 260/360(CS) +P+Q, and the linear motion of the looper roll frame is one-half of this. This movement, it will be seen, is identical with the feed motion of the looper rolls. The cam connection 37 remains in the same position along the slot 35 and the path of the cam returns on itself.
Thus by way of example, if we assume a plate cylinder of 4 inch diameter or l4.92 inches circumference, a throw of 1.4375 inches along arc abcd of cam 33 (that is, omitting any portion of the throw which may be included in arcs d-e or ,f-a to efiect the retarding and accelerating feeding movements P and Q or alternatively assuming these values to be zero and the arcs d-e and f-a to be circles calling for a dwell of the looper rolls throughout their length) and if we assume a pitch radius of 10 inches for segment 29, then the distance a: of the point of connection 37 from the center of motion of the sector for a 7 inch sheet length may be computed from the simplified formula as 5.025 inches and a table might be compiled for other lengths up to .7 of the cylinder circumference, that is, approximately 10% inches. For a full circumference sheet the segment would be clamped stationary.
As a specific example and assuming the plate cylinder 14.92 as above mentioned and a sheet length of '7 inches, the head of the sheet arrives at the form and for 252/360 of a revolution moves a distance of 10.444 inches while the cam follower travels from b to c. From 0 to d the movement continues as an overfeed of .166 inches independent of the sheet length. The head of the sheet may then continue to advance at a variable speed to a distance of P+.l94 inches, that is, P+10/360 S, depending upon the design of the cam, and while the cam follower travels from d to e. During the following 60 the web is fed forward 1.167 inches (60/360 S) by its feed roll. At the same'time it is drawn backward by the action of the looper rolls 5.72+P+Q inches, which may be considered a negative number. Then between points f and a on the cam the web moves forward again .583 inches, that is,
- Q+30/360 S. Finally between a and b there is a forward movement of .166 inches. The algebraic sum of these quantities is seen to be 7' inches so that at the completion of the cycle the head of the sheet has. moved just 7 inches past the bite of the printing rolls and the blank paper immediately following the impression on that sheet is presented ready to be printed on.
In cases oi very short sheet lengths it is advantageous to use a double loop, as indicated in Fig. 3, in which the paper leading from'flxed roll llfpasses over a movable looper roll 13a, hence to a flxed roll 14, back to looper roll 13b, both looper rolls being carried on the reciprocating frame 15, and hence to fixed roll 17 and similarly at the other side of the press. The motion of the looping roll frame is in this instance y. of the paper feed eflected thereby and the momentum or inertia of the motion is thus diminished. Again in the case of a dimension of a '1 inch sheet, if a double loop is utilized, the lever arm through which the pitinan 31 acts on sector 29 would be 10.052 inches. Further advantage in double looping is that it keeps the point of connection of the pitman to the segment within a range where better leverage is secured and not within shorter lengths where any error is multiplied in the segment.
I am aware that the invention may be embodied in other, specific forms without departing from the spirit or essential attributes thereof, and I therefore desire the present embodiment to be considered in all respects as illustrative and not restrictive; reference being had to the appended claims rather than to the foregoing description to indicate the scope of the invention.
1. In a press in combination with rotary printing means. means for feeding a web to and from the same at speeds less than they surface speed of the plate cylinder, looping mechanism, driving means for effecting during a revolution of the cylinder a uniform motion in one direction and an intermediate retracting motion, and ad- Justableimeans for transmiting said motion in desired ratio to the looping mechanism.
2. In a press in combination with rotary printing means, means for feeding a web -to and from the same at speeds less than the surface speed of the plate-cylinder, looping rolls, a rack carrying the rolls, a" sector meshing with the rack,
a cam rotating in synchronism with the plate cylinder having a spiral arc and an intermediate node and a crank arm connection of adjustably variable length between the cam andjthe sector. 3. In a press in combination with rotary print ing means, means for feeding a web to and from the same at speeds less than the surface speed of the plate cylinder, a reciprocable frame having having pairs of rolls thereon, cooperating fixed rolls to permit the web to be trained in a plu- V rality of loops, and means for moving the frame comprising a cam'and a lever transmission of adjustable length. I
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