US2412132A - Printing press - Google Patents

Description

Dec. 3, 1946.. E. F. DEL L PRINTING fRESS 4 Sheets-She t 1 Filed Dec. 5, 1942 a [dwa/ Dec. 3; 1946. E. F. DELL 2,

PRINTING PRESS FiledDec. 5, 1942 4 Sheets-'-Sheet 2 x v I kf i ffiezz/ aj ia ra [lea Patented Dec. 3, 1946 PRINTING PRESS Edward F. Dell, Chicago, 111., assignor to Davidson Manufacturing Corporation, a corporation of Illinois Application December 5, 1942, SerlalNo. 467,924

claims. 1

A printing press is now being manufactured by the Davidson Mfg. .Corporation covered by various patents and patent applications which is suitable f,or both offset lithographic printing and direct printing. This press delivers both types of printing with its printed side up for the sake' of visibility, but prints the under face of the sheet when printing lithographically and the top face of'the sheet in direct printing. This makes possible great simplification of the two-purpose press but the result is that the sheet has to be turned over in the case of lithographic printing and is not turned over in the case of direct printing. To accomplish the optional turn-over simply, the

sheets are discharged at different places for the two types of printing. The press was initially equipped with a collection box which could be positioned at either point of discharge. This press proved to be very satisfactory in spite of" the fact that occasional attention was necessary in order to remove the printed sheets from the collection box before it got too full.

The feeding mechanism of the press includes a pile elevator so that a large pile of sheets can be printed. A similar pile-moving mechanism for lowering the pile at the discharge end of the press was recognized as desirable but its-provision was complicated by the necessity for delivering the sheets at two different positions in order to turn the lithographed sheets over in a simple manner. Furthermore, this optional turnover complicated the timing situation with respect to the joggers which would be provided in connection with pile mechanism since the sheet would naturally take longer to get to the logger when turned over than when not turned over. The side Joggers should be moved apart when a sheet is delivered between them.

According to the present invention, these difficulties have been completely overcome and a very simple mechanism has been provided for carrying the sheets to the pilestacking mechanism from either of the two positions of release from the press and for correcting the timing of the Joggers to fit the circumstances. The receiving of the sheets from either position is accomplished by a very simple form of extensible and tiltable conveyor. In extending the conveyor, it is not necessary to make any adjustment since the belts are, in efiect, automatically paid out as the extension requires.

Additional advantages. and objects of the invention will be apparent from the following description and from the drawings in which Fig. l is a fragmentary side elevation showing the embodiment of the invention chosen for illustration arranged for direct printing;

Fig. 2 shows a plan view of theconveyor of Fig.1;

Fig. 3 is a sectional view through the conveyor table taken approximately on the line 3-3 of Fig. 1;

Fig. 4 is a similar view taken approximately on the line 4-4 of Fig. 1;

Fig. 5 is a fragmentary view corresponding to Fig. 1 but showing the invention arranged for offset printing;

Fig. 6 is a transverse vertical sectional view taken approximately on the line 6-6 of Fig. 1;

Fig. 7 is a fragmentary sectional view taken approximately on the line 1--'| of Fig. 6;

Fig. 8 is a fragmentary sectional view taken approximately on the line 8'-8 of Fig. 6; and

Fig. 9 is a sectional view taken approximately on the line 9-9 of Fig. 6.

A preferred form of the invention hasbeen chosen for illustration and description, in compliance with section 4888 of the Revised Statutes but persons skilled in the art will readily perceive other means for accomplishing the same results, and the claims are therefore to be construed as broadly as possible, consistent with the prior art.

The invention is illustrated in conjunction with a press A having a large cylinder i2 and a smaller cylinder l3. For lithographic printing, the large cylinder may be provided with av plate or platen on different portions thereof while the small cylinder is provided with a blanket so that the blanket receives the image from the plate and transfers it to the under side of the paper which is fed between the blanket and the platen. A'pair of chains 14 are provided with a gripper mechanism it which carries'the sheets into the printing bite, strips them from the printing rolls l2 and I3, and carries them around guide wheels I! to turn them over so they will be delivered with their printed sides up.

For direct printing, it is mostdesirable to have the direct printing plate on the cylinder I! so that the same inking unit may be used as for offset printing. The result is that the upper face 'of the sheet is printed and it is, therefore, de-

sirable to deliver the sheet without turning it over. To this end, a release cam I8 is provided as shown in Fig. 1 which releases the leading end of the sheet just before the gripperv l8 passes around the guide wheels i1. Traction wheels I! may be provided to cooperate with wheels I! to.

3 insure the continued forward movement of the sheet.

For offset printing, where the under face of the sheet is printed, the cam I6 is shifted to an inoperative position and the gripper |6 passes tion, as seen in Fig. 5. 'It will be observed that in the Fig. '1 position, the conveyor is much shorter than in its Fig. position. y In Fig. 1, it need merely reach approximately to the guide wheels l'l whereas in Fig. 5, it must reach in under the guide wheels l1 so as to receive the sheet as it is dropped after being. turned by passing around the guide wheels According to thepresent invention, the conveyor is .not only pivotally mounted to be raised and lowered between the two positions, but it is also extensible so as to be shortened or elongated as required. It is desirable for the end of the conveyor table B which is remote from the press to have a flxed'position for cooperating with the stacking mechanism C. In fact, it is only when such a stacking mechanism is, used that the conveyor table B is essential because if a mere collecting pan is used, that may be placed in the two positions ror releasingthe sheets. As a matter of fact, a, small jogging mechanism may likewise be placed in these two positions, and in each instance be connected to be driven by the'press. The stacking mechanism C, however, is that which is known as a pile Jogger since it is provided with a platform 23 which' may be raised at the beginning of an operation 'and which is .gradually lowered as successive sheets are placed on it so that the top of the the tension of driving belt 63.

Extensible conveyor The conveyor table B is mounted at its delivery end on shaft 3| which is journalled in therrame 26 and carries roller 32 by which the conveyor belts or tapes 33 are driven. The main frame of the conveyor table is made up of plates or side frames 34-and suitable braces 36 extending between them and securing them to each other in properly spaced relationship. The side frames 34 are pivoted to the shaft 3| at the delivery end of the conveyor while their other ends are supported adiustably at the desired height by pivoted bars 31 which, asseen best in Fig. 1, are pivoted at their lower ends to brace". The side bars are held at the desired position on bars-31 by means of thumb screws 36 threaded in brackets 33 on side frames 34. when the screws 33 are loosened, the bars 31 slide freely through the including bars 42 which slides in the-side frames 34 to elongate or shorten the conveyor. Consid- 'ering only the rollers 32 and 4|, it would be apparent that as they are moved toward one another from the extended position of the conveyor to the shorter position of the conveyor there would be a considerable excess of length of the conveyor belts 33 to dispose of. Of course, there are automatic belt tightening devices, but for the most part, these are notsuitable for taking up large lengths of belting such as would have to be taken up for such a shortening of the conveyor.

Furthermore, such tightening devices or automatic tensioning devices would put a tension on the belts which would tend to draw the rollers 32 and 4| toward one another but for the additional features of this invention.

. According to this invention, the 'retum run of the conveyor belts 33 does not run directly from roller 32 to roller 4| but instead runs around idler rollers 43 and 44 so that it doubles back upon itself intermediate the rollers 32 and 4|. The roller 43 is rotatably carried by the side plates 34 while the roller 44 is rotatably carried by the ex tension bars 42. Specifically, the roller 44 may be rotatably mounted in bearing blocks 46 each of which is rigidly carried by one of the bars 42. The roller 4| may be carried by the bars 42 in the same manner. The bearings are preferably ball-bearings.

Since the rollers 4| and 44 are both mounted on the extension bars 42 and since each 01 them has two runs of the belt extending away therefrom, the runs from one extending in a direction opposite to the direction in which they extend from the other, it follows that the tension on -the belt exerts the same force on the extension bars 42 in opposite directions and hence the tension on the belt will have no tendency to move these extension bars and this tension will, therefore,

not move the roller 4| toward the roller 32. Fur-' thermore, as the roller 4| is moved, say six inches in shortening the conveyor, the roller 44 will likewise move six inches in the same direction, and

' v twelve inches of each belt which is thus freed at roller 4| will be consumed or taken up at roller 41 and hence they may fit into open sided slots in the side plates 34. It is not necessary to lock this extension in place since the tension of the belt has no tendency to move it. However, to prevent its shifting due to vibration and the like, a thumb screw 43 is preferably provided.

Movement of the extension. frame or bars 42 in a collapsing direction is restricted by engagement of the lugs 43 which carry roller 4| with the end surfaces of side frames 34. The extending movement is limited by engagement of braces 41 adjacent roller 44 with a stop member 6|. The stop 7 i the space between them when the sheet epproaches longitudinally of the conveyor table. Likewise, as seen best in Fig. 4. the upper portion 66 of the uide plates '63 are flared outwardly and upwardly along 'a substantial portion of the length of the guide plate so as to properly guide between the guide plates the tail end of a sheettwo of the belts 33, the construction is such as to permit their easy movement'to different belts for wider or narrower sheets. Merely by loosening thumb screws 63' and 45', the guides may be shifted apart slightly, lifted off together with bar- 45 from the side plates .34, spacedapproximately to the new spacing and again dropped down beside the belts at that position. There will usually be at least four belts as seen in Fig. 2.

The conveyor belts 33 are driven by roller 32 as previously mentioned, the roller 32 preferably being knurled or fluted and being driven through gears by a ulley 61 which in-turn is driven by a belt 58, the belt 58 being driven from a pulley 69 on the press, this pulley being driven by the press drive. A belt guide 50 is provided for each belt, these beltguides preferably being laterally adjustable on bar 52 carried by links 55. The tension on the belts may be increased by pushing the links 55 and bar 52 downwardly and tightening the securing screws 60.

Joggers I I In order to keep the-pile even, the sheets are jogged into registration thereon by side joggers 24 and end jogger H. The side Joggers 24 are operated by bars 62 which are reciprocated simultaneously in opposite directions by a slotted cam block 63 -Each of the loggers 2a is secured in an adjustable position on one of the barsand slides on the other so that the Joggers are moved toward one another with one stroke of the cam block 63 and away from one another with the return stroke. The cam block 631s operated by a link 66 which is pivoted in lever 66. The lever 66 is rocked by rod 67 which is pivoted at its further end to lever 66 which in turn is rocked in timed relationship with the press as clearly seen in Fig. 5. It may be noted incidentally that this same lever may also operate the feeding mechanism so that both the feeder and the Joggers will be operated inproper timed relationship with the press.

It is important for the logger to be operated in timed relationship to the press so that the.

Joggers will be relatively widely separated when the sheet passes between them so that they will not obstruct movement of the sheet.

The timing of the jogger must be different for the two positions of the apparatus shown in Fig. 1 and Fig. 5. The sheet travels at the same speed in both figures but has considerably further togo in Fig. 5 than in Fig. 1. This variation in timing is accomplished by shifting the position of rod 61 on the lever 66. Thus in Fig. ll, it is seen that the rod 61 is linked to the lever 66 above the shaft 1| on which it is mounted, while in Fig. 5, the rod 61 is linked to the lever 66 below the shaft 1|. Conveniently the cone nection between the rod 61 and lever 66 may be a swivelledblock 12 which is open at its top so that the bar 61' may simply be set into either one of the swivelled blocks 12. The bar 61 is .end jogger 6 I.

. It jogs when the side Joggers a a fraction of the time required for a cycle of the Lever 66 is keyed to shaft 1| which bears near its center a pair of arms 14 for operating the This jogger is mounted on slide rods 15 which slide in slides 16 being urged in a jogging direction by springs 11. In the opposite direction, the rods 15 are actuated by studs 18 on the arms 14 which engage, plates 19 on rods 15. -At least one of the plates 19 is preferably adjustable so that both rods will be actuated at once. V Inasmuch as Jogger 6|, it is lower than the top of the pile and hence there is no necessity for its being timed to operate at the same time as the J'oggers 24.

24 open. The jogger 6| may jog the sheets against any suitable fixed plate (not shown) adiustably positioned to bear against the other ends of the sheets.

Pile lowering mechanism tained there by spring detent 88 engaging a, gauge plate 89. Theposition of the control plate 86 determines the amount that the ratchet wheel 81 is rotated during the stroke of pawl 84 and hence during each cycle of the press. The setting desired Will depend upon the thickness of the sheets.

The ratchet wheel 81 drives a worm 9| which in turn drives a worm wheel 92 keyed to shaft- 93., The shaft 93 has sprockets 94 keyed thereto. A chain -96 runs over the sprockets and raises andlowers the pile platform 23 which is carried by suitable carriages 97 indicated by Fig. 6. The other end of the chain 96 may desirably be counterwelghted' although the weights may well be only heavy enough to ensure that the chains are properly straightened out as they hang down from the sprockets.

To raise the platform 23 at the beginning of a press run or to properly position the pile at any time, the worm may also be turned by the crank 91, operating through gears 98. Suitable means a should be provided for releasing the pawl 84 from the ratchet 81 while the crank 91 is being From the foregoing, it is seen that a press and pile Jogger combination has been provided in which either side of the sheet can be printed and the sheets in either event stacked with their printed faces up on the pile mechanism. Al-

the sheet must pass over this relation with the press lation with the press to open the sheet is delivered, and a pile jogger mechanism from a shiftable end though the sheet has to be turned over in one instance and not in the other and hence may be released from the press proper at". either .of two positions, a conveyor is provided, the receiving end of which can be shifted between the two positions. Although for sary for the conveyor to be elongated and shortened as well as pivoted, a conveyor is provided which is capable of such elongation and shortening without the necessity of any belt adjustments and by a simple telescopic action. Fur-- thermore, a very simple means is provided for changing the timing of the joggers so that with either type of printing, in spite of the fact that the,travel of the sheet takes longerin one instance than in another, the joggers will be widely separated at the between them.

time that the sheet is delivered I clainras my invention: v

l. A printing press including a pair of printing cylinders adapted to print either face of the adapted to turn the sheet it atone position incase the under face is printed and to release it at another position without turning it over when the upper face is printed, a pile jogger mechanism, means for driving the pile jogger mechanism in timed to open the pile jogger as a sheet is delivered, and a conveyor for'delivering the sheets from either of said positions to the pile jogger mechanism pivotable about a point spaced along the conveyor from its receiving end including at least working 'run of which runs forwardly from a shiftable end roller at the receiving end of a portion of the conveyor and the return run of which extends rearwardly to a roller at a fixed position, forwardly around a second shiftable roller and rearwardly to said end roller, the shiftable rollers being joint] shiftable, the movement of the end roller extending the length of the conveyor and the equal movement of the shiftable roller paying out the amount of belt required for said extension whereby the tension on the tape is maintained constant in spite of the changes in the length of the conveyor whereby the .con-

veyor. may readily be adapted to receive sheets at either position.

2. A printing press including a pair of printing cylinders adapted to print either face of the sheet, delivery means adapted to turn the sheet over and release it at one position in case the under face is printed and to release tion without turning it over when the upper face is printed, a pile jogger mechanism, means for driving the pile jogger mechanism in timed repile jogger as a conveyor for delivering the sheets from either of said positions to the including at least one endworking run of which runs forwardly roller at the receiving end of a portion of the conveyor and the return run less belt, the

-. of which extends rearwardly to aroller at a fixed position, forwardly around a second shiftable roller and rearwardly to said end roller, the shiftable rollers being jointly shiftable, the movement of the end roller. extending the length of the conveyor, and the equal movement of the shiftable roller paying out the amount of belt required this purpose, it is neces-' 3. A printin pr ss including a pair of printing 7 cylinders adapted to print either face of the sheet, delivery means adapted to turn the sheet over and release it at one position in case the under face.

is printed and to release it at another position without turning it over when the upper face is printed, a pile jogger mechanism, a conveyor for 1 delivering the sheets from either of said positions tothe pile jogger mechanism, means for driving the pile jogger mechanism in timed relation with the press to open the pile jogger as a sheet is delivered, said conveyor including an extendable portion adapted to pivot about a point of discharge thereof whereby it may be pivoted, and extended or collapsed to properly position its receiving end for sheets released at either position.

4. A printing press including a pair of printing cylinders adapted to print either face of the sheet, delivery means over and release it at one position in case the under face is printed and to release it at another position without turning it over when the upper livering the sheets from one endless belt, the r face. is printed, a pile jogger mechanism, means for driving the pile jogger mechanism in timed relation with the press to open the pile jogger as a sheet is delivered, and a conveyor for deeither of said positionsto the pile jogger mechanism pivotable about a point spaced along the conveyor from its receiving end including at least one endless belt, the working run of which runs forwardly from a shiftable end roller at the receiving end of a portion of the conveyor and the returnrun of which extends rearwardly to a roller at 'afixed position, forwardly around a second shiftable roller and rearwardly to said end roller, and a frame on which said shiftable rollers are both mounted, said frame being shiftably mounted for changing the length of the conveyor by moving both the it at another posi-r thereof whereby it may be and a conveyor change of'length of the on the tape uniform in spite of the conveyor and whereby the tension has no tendency to move the frame.

5. A printing'press including a pair of printing cylinders adapted to print either face of the sheet, delivery means adaptedto turn the sheet over and release it at one position in case the under face is printed and to release it at another position without turning it over when the upper face is printed, a pile jogger mechanism, for delivering the sheets from either of said positions to the pile jogger mechanism, said conveyor including an extendable portion adapted to pivot about pivoted, extended or I collapsed to properly position its receiving end for sheets released at either position, said pile jogger including side jogger means, and driving means for jogging the side jogger means inwardly and'outwardly against the sides of sheets deposited therebetween, said driving means being for said extension whereby the tension on the tape is driven in timed relationship with the press to hold open the side jogger means as a sheet is deposited therebetween, and means for easily adjusting the driving means to change the timed relationship between the side'joggers and the press to make the timing correct for the two different release positions of the sheet to the conveyor.

6. The combination of a press adapted to print either face of a sheet, pile jogger means including side Joggers and delivery means adapted to turn the printed sheet over and deliver it to the pile adapted to turn the sheet end roller and the shiftable roller a point of discharge 9 jogging means or optionally delivering itto the pile jogging means without turning it over, the delivery taking longer in one instance than the other, and means to drive the jogging means in timed relationship with the press and to vary the timed relationship so that with a sheet printed on either face and deliveredto the jogging means with its printed face up, the side Joggers of the jogging means will open to receive the sheet.

7. The combination of a press adapted to print either face of a sheet, pile jogger means and delivery means adapted to turn the printed sheet over and deliver it to the pile jogging means or optionally delivering it to the pile Jogging means without turning it over, the delivery taking longer in one instance than-the other, and means to drive the jogging means in timed relationship with the press and to vary the timed relationship so that with a sheet printed on either face and delivered to the jogging means with its printed face up, the side Joggers oi the jogging means will open to receive the sheet, said driving means including a lever pivoted intermediate itslength, open-sided pivoted blocks mounted on the lever with one on each side of the pivotal axis of the lever, and a rod reciprocated in timed relationship with the press and adapted to be dropped into the open side of either of said blocks and to oscillate the lever by coaction with said block.

8. The combination of a press adapted to print either face of a sheet, pile Jogger means and delivery means adapted to turn the printed sheet over and deliver it to the pile jogging means or optionally delivering it to the pile jogging means without turning it over, the delivery taking longer in one instance than the other, and means to drive the jogging means in timed relationship 10 of said blocks and to-oscillate the lever by coaction with said block; said rod having two spaced lugs positioned thereon, one of which engages one block'when the rod is therein and the other of which engages the other block when the rod is therein,'whereby the lever is driven in the same angular direction by said block in either position, the lever being biased in the opposite direction.

l0. Sheet handling apparatus including a machine for performing an operation on the sheets including a rotary element of generally cylindrical contour, 'means running around the rotary element and adapted to move the sheet, means for causing release of the sheet at the top of the rotary element with movement generally tangentially and forwardly therefrom, and means alternatively effective for causing release of the sheet after it has passed around the rotary element,

an extensible conveyor including a main frame V pivotable about a point spaced forwardly from said element, a shiftable frame shiftable forwardly and rearwardly with respect to the main frame,

a first conveyor roller carried by the main frame,

a shiftable end roller carried by the shiftable frame, a stationary looper roller carried by the frame positioned longitudinally between the end roller and the first conveyor roller, and a shiftable looper roller carried by the shiftable frame longitudinally between thefirst conveyor roller and the stationary looper roller, and a conveyor belt having its upper run extending forwardly from I the shiftable end roller to the first conveyor with the press and to vary the timed relationship so that with a sheet printed on either face and deliveredto the logging means with its printed face up, the side Joggers of the-jogging means will open to receive the sheet, said driving means including a lever pivoted intermediate its length, open-sided pivoted blocks mounted on the lever with one on each side of the pivotal axis of the lever, and a rod reciprocated in timed relationship with the press and adapted to be dropped into the open side of either of said blocks and to oscillate the lever by coaction with said block;

said rod having two spaced lugs adjustably posi-' tioned thereon, one of which engages one block when the rod is therein, and the other of which engages the other block when the rod is therein,

whereby the leveris driven in the same angular direction by said block in either position, the

lever being biased in the oDDOsite direction.

*9. The combination 01' a press adapted to print either face of a sheet, pile jogger means and delivery means adapted to turn the printed sheet over and deliver it to the pile jogging means or optionally delivering it to the pile jogging means without turning it over, the delivery taking longer in one instance than the other, and means to drive the jogging means in timed relationship with the press and to vary the timed relationship so that with a sheet printed on either face and delivered to the jogging means roller and its lower run extending rearwardly to and forwardly from the stationary looper roller around the shiftable looper and rearwardly to the shiftable end roller whereby the conveyor may be elongated and pivoted to receive sheets at either position of release without changing the tension on the belt and without the necessity of overcoming any force exerted on'the rollers-by the belt.

11. An extensible conveyorincluding a main frame; means pivotally mounting the frame adjacent to one end thereof, adjustable me' ans v 5\moun ting the other end of the frame so that the height of the second mentioned end can be regulated, a shiftable frame shiftable generally longitudinally in the main frame, a first co'nveyor roller carried by the main frame, a shiftable end roller carried by the shiftable frame, a stationary looper roller carried by the main frame toward the and roller from said first conveyor roller, and a shiftable looper roller carried by the shiftable frame toward the first conveyor roller from the stationary looper roller, and a conveyor belt having its upper run extending forwardly from the shiftable end roller to the first conveyor roller and its lower run extending rearwardly to and forwardly from the stationary looper roller around the shiftable looper roller.

12. Sheet handling apparatus including a machine for performing an operation on the sheets including a rotary element of generally cylindrical contour, means running around the rotary with its printed face up, the side joggers of the jogging means will open to receive the sheet, said driving means including a lever pivoted intermediate its length, open-sided pivoted blocks mounted on the lever with one on each side of the pivotal axis of the lever, and a rod reciprocated in timed relationship with the press and adapted to be dropped into the open side of either element and adapted to move the sheet, means for causing release of the sheet at the top of the rotary element with movement generally tangentially and forwardly therefrom, and means alternatively effective for causing release of the sheet after it has passed around the rotary element, an extensible conveyor including a main frame pivotable about a point spaced forwardly from .said element, a shiftable frame shiftable forwardly and rearwardly with respect to the main frame, a first conveyor roller carried by the main frame, a

and from it, again 1 11 I J shiftable end roller carried by the shiftable frame, a stationary looper roller carried by the frame positioned longitudinally between the end roller and the first conveyor roller, and a shiftable looper rollercarried bythe shiftable frame Ion-: conveyor roller and .thestationary looper roller, and a conveyor belt gitudinally between the first also upwardly to guide a sheet which approaches it endwise on the tape or from above.

13. An extensible conveyor including a pa-ir of frames one constituting, a main frame, means pivotally mounting the main frame adjacent to one endthereof, adjustable means mounting the other end of the frame so that the height of the second mentioned end can be regulated, each frame including a pair of generally parallel rollers longitudinally spaced thereon, said frames being associated with one another for relative longitudinal movement, with the span between the roll ers on one frame overlapping the span between the .rollers on the other frame, a belt having its between the most,

upper run passing over and remote of said rollers and having the return run extending in a first direction froni a'flrst of saltremote rollers to the otherjrollerijon the same frame therewith around this I I opposite direction to the fourt ller, around it in the first direction, the other of the remote rollers whereby the frames may be shifted to elongate the conveyor without changing the tension of the belt.

14. An extensible conveyor frames, each frame including a pair of generincluding a pair of 12 ally parallel rollers longitudinally spaced-thereon, said frames being associated with one another for relative longitudinal movement, with the span between the rollers on one frame overlapping the span between the rollers on the other frame, a belt having its upper run passing over, and between the most remote of said rollers and having the return run extending in a first direction from a first of said remote rollers to the other roller on the same frame therewith around this roller and in the opposite direction to the fourth roller, around it and from it, again in the first direction,

to the other of the remote rollers whereby the frames may be shifted to elongate the conveyor without changing the tension of the belt, and means pivotally mounting the conveyor about the axis of one of said remote rolls. t I 15. A printing press including a pair of print ing cylinders adapted to print either face of the sheet, delivery means adapted to turn the sheet over and release it at one position in case the under face is printed and to release it at another position without turning it over when the upper face is printed, a depositing surface spaced different distances from the first and second Positions, and a conveyor delivering the sheets from either of said positions to thedepositing surface pivotable about a point spaced along the conveyor from its receiving end including at least one endless belt, the working run of which runs forwardly from a shiftable end roller at the receiving end of a portion of the conveyor and the return run of which extends rearwardly to a roller at a fixed position, forwardly around a second shiftable roller and rearwardly to said end roller,

.tl'ieshi'ftable rollers being jointly shiftable. the movement of the end roller extending the length of the conveyor, 'and the equal movement of the shiftable roller paying out the amount of belt required for said extension whereby the tension on the tape is maintained constant in spite of the changes in the lengthof the conveyor whereby the conveyor may readily be adapted to receive sheets at either position.

EDWARD F. DELL.

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