US2276269A - Sheet delivery mechanism - Google Patents

Description

March 17, 1942, E. F. DUDLEY ,2

SHEET DELI-IVER! MECHANISM Filed Sept. 9, 1940 s Sheets-Sheet 1 INVENTCR.

March 17, 1942. E. F. DUDLEY 927g28g SHEET DELIVERY MECHANISM 7 Filed Sept. 9, 1940 3 Sheets-Sheet 2 INVENTOR III Edward [17% fi fi I f I I v I v I March 17, 1942 E. F. DUDLEY SHEET DELIVERY MECHANISM Filed Sept. 9, 1940 3 Sheets-Sheet 3 Patented Mar. 17, 1942 I. OFFICE SHEET DELIVERY MECHANISM Application September 9, 1940, Serial No. 355,976

14 Claims. (Cl. 101-276) The present invention, while intended for cylinder printing presses of any class, finds its particular usefulness in machines of the vertical type, for instance where the impression cylinder reciprocates in a vertical path, or where the impression cylinder and the type bed both reciprocate vertically and in opposite directions, such as is the case in the well-known Miehle vertical press. The invention has for its principal aim the provision of improved sheet delivery mechanism whereby it shall be possible to considerably increase the hourly production of such presses.

The particular type of delivery mechanism to which my invention applies is that whereby the printed sheets are conveyed from the impression cylinder to a sheet receiving table by means of reciprocating grippers.

Heretofore, when presses equipped with such delivery mechanism were operated at speeds up to 3600 impressions per hour, the printed sheets could be successfully delivered. However, when attempts were made to increase the production of such presses to reach an output of 5000 sheets per hour and over, considerable difiiculties were encountered.

The means for imparting reciprocatory movement to the grippers consisted in the past of mechanism which would produce a regular crank motion; this was quite satisfactory for presses operating up to the lower speed limits stated delivery stroke. It is quite important, I have found, that near the end of their return stroke, the velocity of the grippers again should be very low so that vibration of'the grippers shall be avoided at the moment when they engage a sheet for removal from the cylinder and reverse their direction of travel in order to deliver the sheet. One of the primary objects of my invention therefore is to produce an improved method of delivering sheets and novel means whereby the delivery gripper motion indicated above can be accomplished in a positive and simple manner;

Another object of my invention resides in the provision of means which shall be contributory to the successful delivery of sheets at high rates of i press speed;

above. It became evident, however, that in order to smoothly and satisfactorily deliver sheets at higher speeds, radical changes must be made in the mechanism for actuating the reciprocating delivery grippers.

Primarily, in order to remove a printed sheet from the impression cylinder so that it shall be clear of any operating parts which move within the zone of travel of a sheet while it is being removed from the impression cylinder, it was found that the velocity of the grippers must be accelerated considerably above the maximum velocity which a crank motion could produce. After the tail end of the sheet has cleared the impression cylinder, the delivery grippers should be subjected to a gradual, uniform deceleration so that near the end of their delivery stroke the grippers shall assume a greatly reduced velocity, thereby avoiding any buckling of the sheet that is being delivered, and permitting the sheet to be released and dropped onto the delivery table when its velocity is practically nil.

During their return stroke toward the impression cylinder, the motion of the delivery grippers should be similar to that assumed during their A further object of my invention is to provide actuating mechanism whereby the path of travel of the sheet engaging grippers shall be positively controlled by cam means;

Further objects of my invention will be apparent from the following description and accompanying drawings, in which:

Figure 1 represents diagrammatically and in side elevation, a printing press of the vertical type, illustrating the preferred means whereby motion is imparted to the delivery grippers of the press;

Figure 2 is a similar view of the press but showing the operating parts in different positions;

Figure 3 depicts a comparative speed graph to illustrate the improved gripper motion as compared with that produced heretofore by means of a crank mechanism;

Figure 4 is a diagrammatic illustration of a preferred means whereby the path of travel of the delivery grippers is changed;

Figure 5 shows th same means but with the parts in diiierent positions;

Figure 6 shows the relative position of the delivery grippers and the impression cylinder just before the end of the upward stroke of the cylinder; and

Figure 7 illustrates the impression cylinder in its position at the end of its upward stroke and the delivery gripeprs having engaged the leading edge of the sheet on the cylinder.

In the preferred embodiment of my invention, see Figures 1 and 2, the printing press in connection with which this invention is applied, includes a base frame In and an upper frame member H which accommodates a type bed l2 having bearers to cooperate with bearers l3 of the impression cylinder M as is well-known in the construc. tion of bed and cylinder printing presses.

The sheets to be printed are fed onto a registering table I5 and, after being registered by conventional registering mechanism, not shown, they are engaged b grippers [6 of the impression cylinder M and are subsequently printed during the upward stroke of said cylinder at the end of which stroke the latter assumes the position shown in Figure 1.

In printing presses of the type referred to, the registering table I5 is arranged to move up and down with the impression cylinder l4 and in addition to this movement, it is also given a tilting motion. When the cylinder is in its uppermost position, as shown in Figure 1, the front edge of the table is raised above the cylinder grippers l6, so that the table tilts backward to receive a sheet 60 from the feeder, not shown. As soon as the cylinder I4 commences its downward stroke, the table it, with its sheet thereon, will also begin to move downward and at the same time start to tilt forwardly and downwardly in order to eventually effect the final front registration of the sheet against the guide portions of the cylinder grippers 6, a position shown in Figure 2.

It will be understood that with the press running at high speeds, such as I have indicated herein, there is very little time available for removing the sheet from the impression cylinder and clear it before the front edge of the registering table l5 approaches the cylinder. The problem which presented itself, therefore, was to provide a means whereby a sheet is removed from the impression cylinder at the highest possible velocity. This problem I have solved with the means now to be described.

The delivery grippers ll, which are carried at the outer ends of arms 18, arranged at each side of the frame member II and pivoted at l9 therein, are actuated by a cam 2ll through the intermediary of rocking lever 2|, link 22 and arm 23 in order to reciprocate between the impression cylinder I4 and the delivery pile table 24 and convey printed sheets from the cylinder onto said table.

The cam which actuates the delivery gripper arms i8 and whereby the desired motion of the grippers I6 is obtained, embodies the characteristics of roll-curves, that is to say, the motion produced thereby is smooth and completely void of any shocks. type, with which cooperate two cam rollers 26 and 21 carried by the lever 2 l, the roller 26 riding over the inner cam face 28 and the roller 21 riding over the outer cam face 29 of the cam ridge.

In order to clearly illustrate the motion that is to be imparted to the delivery grippers during their complete cycle of operation, I have represented in Figure 3 what may be termed a comparative speed graph. There are two curves, A and B, the former indicating that speed graph which represents the motion produced by a crank drive such as was heretofore used for driving the delivery gripper on the same type of press in connection with which my present invention is illustrated.

The curve 13, however, depicts the improved delivery gripper motion whereby it is now possible to increase the practical operating speed of such presses from the heretofore attained maximum speed limit of 3600 impressions per hour to the present practical speed of 5000 impressions per hour and over.

When one observes the curve A, which represents the motion produced by a crank mechanism,

it will be seen that neither at the end of the de- Preferably said cam is of the ridge livery stroke, nor at the time when the delivery grippers approach the impression cylinder, will there be a gradual slowing down and dwell of the grippers. Therefore, at either extreme of their reciprocatory movement, the grippers are not imparted the smooth motion that is essential when increased delivery speeds, such as I have indicated herein, are to be attained.

' In order to make possible a slow approach of the delivery grippers to take a printed sheet from the impression cylinder, and again to retard the grippers at the delivery end, so that a sheet may be deposited onto the pile table smoothly and with a minimum velocity, it is necessary to gain time at other periods in the cycle of operation of the grippers. This I accomplish by a cam motion depicted by the speed graph curve B. According to this improved motion, the acceleration of the grippers, beginning at their delivery end, shall be constant and their velocity shall have reached its maximum at about whereupon the deceleration begins and shall be constant until approximately From then on the deceleration is such that the delivery grippers approach the impression cylinder grippers at a very low velocity.

It is apparent, therefore, that the maximum velocity of the delivery grippers reached according to the curve B is considerably in excess of the maximum velocity attained by means of a crank drive which the curve A represents. Accordingly, the time gained thereby can be utilized to make possible the degree of deceleration required for the smooth delivery of sheets at the increased press speeds indicated herein. The preferred speed graph curve B indicates that the rate of acceleration and of deceleration imparted to the delivery grippers during their delivery stroke, namely from the impression cylinder to the delivery table, is similar to that given to said grippers during their return stroke, namely in the direction from said table to said cylinder. The velocity ratios could, however, be changed, without departing from the essence of my invention.

In Figures 1 and 2 I have indicated in broken lines the approximate paths over which the delivery grippers ll are caused to travel during their reciprocatory motion. The reference character I denotes the path of travel of said grippers during their sheet delivery stroke, whereas the reference II indicates the approximate course which the grippers assume during their stroke toward the impression cylinder I4.

Path I shows that as soon as the delivery grippers I! have engaged a sheet in order to remove it from the cylinder I4, they raise with the sheet, thereby partly stripping it from the cylinder, and then proceed rearwardly over a practically horizontal path, so that the sheet to be delivered shall reach the delivery table 24 perfectly flat and as near as possible to the top plane of the table or of sheets previously deposited onto said table. After having released the sheet, the grippers l'l move beyond the rear edge of the table 24 and pass between a series of delivery sheet stop fingers 25 which arrest any further forward movement of the released sheet.

It has been found that quite frequently, particularly in cases where rather thin, i. e. light weight stock was handled at high speeds, the delivery grippers, when returning to the impression cylinder over the same path as during their travel when delivering the sheets, would occasionally strike a sheet that has just been delivered, thereby damaging it and causing interruptions and delay in the printing production.

I therefore conceived means whereby the grippers shall be raised after having released a sheet and be maintained in such raised position during their return stroke, thereby avoiding any interference of the grippers with the sheet while it is settling or floating down onto the delivery table.

According to path II, the delivery grippers, after having passed between and beyond the stop fingers 25, are raised into a plane considerably above that of path I, and they will maintain such raised position until the delivery table 24 is cleared. Then the grippers are caused to dip in order to engage and remove the next sheet from the cylinder 14.

A preferred mechanism for accomplishing this gripper motion is illustrated in Figures 4 and 5. It includes a rock arm 30 arranged to pivot about a stud 3| in order to be raised and lowered into different operative positions. The'arm 30 is actuated by means of a rotary timing cam 32 which has a contour designed to impart to said arm and therewith to the grippers I! the desired motion. A roller 33 cooperates with said cam, which roller is carried by the lower end of a connecting rod 34, the upper end of which is pivoted to the end 35 of said arm. The mounting 40 of the delivery grippers H has a rearwardly extending arm Al to the outer end of which is pivoted a connecting rod 42 whereby the grippers I! may be rocked about the stud 43 provided in the outer end of the arm l8. Said rod extends downwardly through a bracket 44, which is secured to the delivery gripper arm [8, and at its lower end the rod is connected to the arm 45 of the bell crank lever 46 which is pivoted at 4'! to the gripper arm I8. A cam roller 48 is provided on said bell crank lever to ride over the cam surface 49 on the rock arm 30. A compression spring 50 which surrounds the rod 42 and bears against the bracket 44 and against an adjustable collar secured to said rod, urges the roller 48 downwardly in order to maintain rolling engagement with the cam surface i9. It will be understood, therefore, that when the high portion 55 of the cam 32 presents itself to the roller 33, the arm 3|] and therewith the cam surface 49 will be up, causing the rod 42 to be pulled down and thereby swing the grippers l1 upwardly as shown in Figure 4. When, however, the roller 33 rides over the low portion 56 of the timing cam, the parts will assume the positions which they maintain during the sheet delivery stroke of the gripper arms is and grippers l1, see Figure 5.

The means for opening and closing the delivery grippers may be of any suitable kind and are not illustrated here because they do not form part of this invention.

In Figure 6 I have illustrated the relative position of the delivery grippers l1 and the impression cylinder grippers l6 during that period immediately prior to the impression cylinder reaching the limit of its upward stroke; while in Figure 7 I have shown said cylinder in its uppermost position with its grippers I6 open and the delivery grippers having just engaged the leading edge of the sheet 60.

For the purpose of facilitating the delivery of stock such as thin and flimsy sheets which are difiicult to control while settling or floating down onto the delivery table, I provide a series of air blast nozzles of any suitable design and which,

as shown in Figures 1 and 2, are carried by a blower tube H arranged above the table 24. These nozzles are adjustable within given limits so that the blast of air ejected therefrom may be directed to impinge onto a sheet at different angles.

It will be understood that while I have described and illustrated one specific embodiment of my invention, I intend to cover any such constructional modifications and different modes of application as will come within the meaning and scope of the appended claims.

I claim:

1. In a bed and cylinder press of the vertical class, a rotary impression cylinder and a type bed cooperating therewith, a delivery pile table, reciprocating sheet delivery means for removing sheets from said cylinder and conveying them across the operating path of said impression cylinder and type bed and depositing them onto said table, mechanism for actuating said delivery means to assume a maximum delivery speed which shall be in excess of the maximum surface speed of said cylinder, and means for causing the delivery means to travel in different planes during their delivery and return strokes.

2. In sheet delivery mechanism for printing. presses of the stop cylinder class, the combination of reciprocating delivery means, a sheet receiving table, and cam means for actuating said delivery means to convey a sheet from said cylin; der and deposit it onto said table, said cam means having such characteristics that the delivery means approach said cylinder at a reduced rate of speed, momentarily stop to receive a sheet from said cylinder, remove the sheet therefrom at uniformly increased acceleration, then assume a uniform deceleration to deposit the sheet onto said table when the velocity of said delivery means is substantially nil.

3. In sheet delivery mechanism for printing presses of the stop cylinder class, the combination of reciprocating delivery grippers, a sheet receiving table, and cammeans for actuating said delivery grippers to convey a sheet from said cylinder and deposit it onto said table, said cam means having such characteristics that the delivery grippers approach said cylinder at a reduced rate of speed, momentarily stop to receive a sheet from said cylinder, remove the sheet therefrom at uniformly increased acceleration, then assume a uniform deceleration to deposit the sheet onto said table when the velocity of said delivery grippers is substantially nil, said delivery grippers, during their travel toward said impression cylinder moving in a path above the path in which they travel toward said receiving table.

4. In sheet delivery mechanism for printing presses of the stop cylinder class, the combination of reciprocating delivery grippers, a sheet receiving table, means for moving said grippers into sheet engaging and sheet delivering positions, means for opening the grippers to release a sheet, and means for raising said grippers after having released a sheet for delivery onto said table and for maintaining them raised substanstantially during their entire return movement toward the sheet engaging position for the purpose of clearing the sheet just released by the grippers.

5. In a printing press of the stop cylinder class, the combination of a vertically reciprocating impression cylinder, a sheet delivery table, delivery grippers, and mechanism including cam means for actuating said grippers to engage a sheet while the impression cylinder is in its upvertically reciprocating impression cylinder, a

sheet delivery table, delivery grippers, and mechanism including cam means for actuating said grippers to engage a sheet while the impression cylinder is in its uppermost position and at rest and convey the sheet across the path of reciprocation of said cylinder to said delivery table, said cam means having such characteristics that the delivery means approach said cylinder at a reduced-rate of speed, momentarily stop to receive a sheet from said cylinder, remove the sheet therefrom at uniformly increased acceleration, then assume a uniform deceleration to deposit the sheet onto said table when the velocity of said delivery means is substantially nil.

7. In a printing press of the stop cylinder class, the combination of a vertically reciprocating impression cylinder, a sheet delivery table, delivery grippers, and mechanism including cam means for actuating said grippers to engage a sheet while the impression cylinder is in its uppermost position and at rest and to convey the sheet from said cylinder to said delivery table, means for releasing the sheet, and means for raising said delivery grippers after having released a sheet and for maintaining them in such raised position substantially during their entire return stroke toward the impression cylinder for the purpose of clearing the sheet just released.

8. In a printing press of the stop cylinder class, the combination of a vertically reciprocating impression cylinder, a sheet delivery table, delivery grippers, and mechanism including cam means for actuating said grippers to engage a sheet while the impression cylinder is in its uppermost position and at rest and convey the sheet to said delivery table, and means for raising said delivery grippers after having delivered a sheet and maintain them in such raised position during their return stroke toward the impression cylinder, said cam means having such characteristics that the delivery means approach said cylinder at a reducedrate of speed, momentarily stop to receive a sheet from said cylinder, remove the sheet therefrom at uniformly increased acceleration, then assume a uniform deceleration to deposit the sheet onto said table when the velocity of said delivery means is substantially nil.

9. In a printing press of the stop cylinder class, the combination of a printing couple, including a vertically reciprocating impression cylinder, a sheet delivery table, delivery grippers, and mechanism including cam means for actuating said grippers to engage a sheet While the impression cylinder is in its uppermost position and at rest and convey the sheet from and across the path of reciprocation of said cylinder to said delivery table, means for releasing the sheet, and means for raising said delivery grippers after having delivered a sheet and for maintaining them in such raised position substantially during their entire return stroke toward the impression cylinder for the purpose of clearing the sheet just released by the grippers.

10. In a printing press of the stop cylinder class, the combination of a vertically reciprocating impression cylinder, a sheet delivery table, delivery grippers, and mechanism including cam means for actuating said grippers to engage a sheet while the impression cylinder is in its uppermost position and at rest and convey the sheet to said delivery table, a series of adjustable air blast nozzles for controlling a sheet while it is being delivered onto said table, said cam means having such characteristics that the delivery means approach said cylinder at a reduced rate of speed, momentarily stop to receive a sheet from said cylinder, remove the sheet therefrom at uniformly increased acceleration, then assume a uniform deceleration to deposit the sheet onto said table when the velocity of said delivery means is substantially nil.

11. In a printing press of the stop cylinder class, the combination of a printing couple, including a vertically reciprocating impression cylinder, a sheet delivery table, delivery grippers, and mechanism including cam means for actuating said grippers to engage a sheet while the impression cylinder is in its uppermost position and at rest and convey the sheet across the path of reciprocation of said cylinder to said delivery table, a series of adjustable air blast nozzles for controlling a sheet while it is being delivered onto said table, said cam means having such characteristics that the delivery means approach said cylinder at a reduced rate of speed, momentarily stop to receive a sheet from said cylinder, remove the sheet therefrom at uniformly increased acceleration, then assume a uniform deceleration to deposit the sheet onto said table when the velocity of said delivery means is substantially nil.

12. The method of delivering sheets on printing presses having reciprocating sheet engaging members for conveying sheets from an impression cylinder to a sheet receiving table, including the steps of causing said members to slowly approach and grasp the front edge of a sheet while on the impression cylinder, raising said members and therewith stripping the sheet from said cylinder, moving the entire sheet at a highly accelerated velocity away from the cylinder and until the sheet has cleared the cylinder, decelerating said members, releasing the sheet while its velocity is a minimum, raising said members and returning them at an accelerating velocity towards said cylinder, and finally lowering said members and moving them at a greatly decelerated velocity to engage the next sheet to be delivered.

13. The method of delivering sheets on printing presses having reciprocating sheet engaging members for conveying sheets from an impression cylinder to a sheet receiving table, including the steps of causing said members to slowly approach and grasp the front edge of a sheet while on the impression cylinder, raising said members and therewith the front edge of the sheet above said cylinder, moving the entire sheet at a highly ccelerated velocity away from and across the operating path of said cylinder and in a substantially horizontal path, decelerating said members, releasing the sheet while its velocity is a minimum, raising said members above their sheet delivering path, again ac- 10 sheet just delivered.

livery member to assume a maximum delivery speed which shall be in excess of the maximum surface speed of said cylinder during its printing stroke, and means for causing said member to travel during its delivery stroke in a substantially horizontal path in close proximity to the level at which sheets are to be deposited, and during its return stroke in a path located substantially above said level for the purpose of clearing the EDWARD F. DUDLEY.

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