US1988970A

US1988970A - Lithographing press

Info

Publication number: US1988970A
Application number: US529111A
Authority: US
Inventors: Hotchkiss William Roy
Original assignee: Individual
Current assignee: Individual
Priority date: 1931-04-10
Filing date: 1931-04-10
Publication date: 1935-01-22
Anticipated expiration: 1952-01-22

Description

w. R. HOTCHKISS 1,988,970

LI THOGRAPHI NG PRES S Jan. 22, 1935.

Filed April 10, 1931 6 Sheets-Sheet l Jan. 22, 1935. w. R. HOTCHKISS 41,988,970

LITHOGRAPHING PRES 5 Filed April 10, 1931 6 Sheets-Sheet 2 #711 "WWW I: I i I J7 g n center Jan. 22,1935. w R HQTHK|S$ v 1,988,970

I I LITHOGRAPHING PRESS I Filed April 10. 1931 6 Sheets-Sheet 3 22, 1935- w. R. HOTCHKISS LITHOGRAPHING PRESS Filed April 10, 1931 6 Sheets-Sheet 4 Williwmflqyflolohkiss Jan. 22, 1935. w R o c ss I 1,988,970

LITHOGRAPHING PRES S Filed April 10, 1931 6 Sheets-Sheet 5 I I /l v #7 gay-11 snow Roz 9h'zzmmea wmzss 1935- w. R. HOTCHKISS 7 1,988,970

LITHOGRAPHING PRES S Filed April 10, 1931 6 Sheets-Sheet 6 gwwnloz William Roy .bbhiI/ZWJSS LHP Patented Jan. 22 1935 UNITED STATES PATENT OFFICE LITHOGRAPHING PRESS William Roy Hotchkiss, St. Paul, Minn.

Application April 10, 1931, Serial No. 529,111

Claims.

, means for the sheets from the stack to the grippers which includes the automatic registering of each sheet as the sheet travels into lithographing position, and this structure includes clutch means causing the feeding mechanism to be inoperative from the stack, while the sheet conveying means continues to operate as long as the machine is operating so as to carry the sheets through the press. The conveyor means is designed to operate to register the sheets against the register gauge so as to bring each sheet intoproper registry before it is gripped by the gripping fingers of the impression cylinder and when the sheet reaches the position of proper registry, fingers aredesigned to hold the same until the sheet has been firmly gripped by the gripping fingers, the holding fingers being designed to release automatically only after the gripping fingers began to draw the sheet around the impression cylinder. This insures the maintaining of registry of the sheets to be lithographed by preventing any slipping of the sheet from the moment it reaches registry until it is lithographed.

The press includes a structure having a novel form of means for automatically stopping the press and simultaneously throwing out of contact the lithographing elements in the absence of a sheet to be lithographed in the press. If, for any reason in the operation of the press, a sheet fails to be carried to the impression cylinder, the tripping mechanism of the press automatically releases the ofiset blanket cylinder which is simultaneously caused to move out of contact with the impression plate and the lithographing cylinder. The structure for accomplishing this result is of a different character than has been used heretofore, having a simple and positive action. The tripping mechanism also operates an electric switch which stops the press.

The press is designed to provide a particular mounting for the plate, offset blanket and im-' pression cylinders. The plate cylinder which is and inking unit is supported in a bearing to permit vertical adjustment, and the impression cylinder is positioned below in vertical alinement with the plate cylinder, being mounted in avertically adjustable bearing. The blanket cylinder is interposed between the plate and impression cylinder and is held by horizontally adjustable and slidable bearings, together with locking means for holding it into and out of operative position with the other cylinders. This provides a means of mounting the operating cylindersof the lithographing press so that the operation is very simple and permits the operator to set the press more easily. After the press is set, accurate registry is maintained throughout the operation of the job even though the blanket cylinder of the press is repression cylinder, or for any other reason that it is found necessary to stop the machine in the operation thereof. It is quite apparent that in some'ofiset presses in lithographing it is diflicult to maintain accurate registry even in the operation of the machine. I believe that my simple effective structure has .overcome this in the mounting and arrangement of the operating cylinders.

leased any time a sheet fails to vpass to the im- The press is provided with a peculiar type of gripping fingers for the impression cylinder which operate to virtually rotate a half a turn in releasing and gripping a sheet to be carried over the impression cylinder. This structure permits the sheets to be more easilydischarged from the impression cylinder so that they can be carried away from the same. The impression cylinder is provided with lifting pins which co-operate with the releasing of the gripping fingers.

A further feature of my press resides in the unitary arrangement of the moisture and inking unit which is provided with means for elevating the same out of operating position without disturbing the remainder of the press. Thus this unit may be lifted'at any time out of contact and operation with the plate cylindera In this manner the moisture and inking unit may continue to operate elevated out of registry with the plate cylinder, thus maintaining the uniform distribution of the ink and moisture in the same so as not to change the character by stopping of this unit even though it is desirable to have the ink and moisture unit out of operation with the plate cylinder.

These features together with other details, objects and advantages which provide a lithographing press of a character for more efficiency and easier operation be more fully and clearating handle for elevating the inking and moisture unit. 7

Figure 5 is a diagrammatic side view of a portion of my press.

Figure 6 is a diagrammatic detail of the inking and moisture unit as amociated with the plate cylinder.

Figure 7 is a diagrammatic side view of a detail of the sheet holding means.

Figure 8 is a sectional detail of the impression cylinder and the sheet holding means.

Figure 9 is a diagrammatic detail of the press tripping levers. I

Figure 10 is a similar view to Figure 9, showing the parts in a different position.

Figure 11 is a diagrammatic detail of the blanket cylinder locking means and bearing.

Figure 12 is a section of the impression cylinder.

Figure 13 is an end view of the impression cylinder, showing the cam and gear means for operating the gripping fingers of the same.

Figure 14 is an end view of the opposite end of the impression cylinder to Figure 13, showing the cam means for operating the ejector pin lever.

Figure 15 is a plan view of the sheet conveyor means.-

Figure 16 is a sectional detail, showing the clutch for releasing the sheet feeding rolls at the stack table.

Figure 17 is a detail of the electric switch operating means to stop the operation of the. machine. My lithographing press A is provided with a feeding table 10 of a desirable nature which may be provided with side members 11 between which sheets may be stacked on the table 10. The sheets are adapted to be fed from the table 10 by the feeding roller 12 which is operated intermittently by the rack 13. The rack 13 is operated .by the lever 14 and the cam 15. This operates the feeding roll 12 to feed one sheet at a time to the sheet conveying table 16 which extends at an upward incline from the roll 12 and which is provided with sheet feeding rolls 17 positioned adjacent the feeding roll 12.

' The cam 15 is carried by the shaft 18 which is adapted to be operated by the clutch 19 to rotate the shaft when the clutch 19 is in operative position. When the clutch 19 is disengaged as illustrated in Figure 16, the shaft 18 remains stationary while the auxiliary shaft 20 mounted on the shaft 18 continues to operate. The shaft 20 is driven by suitable chain means 21 which extends to the line of power'ofthe machine. The clutch 19 is normally held in operative position by the coil'spring 22 and by means of the hand lever 23 which projects on one side of the machine A, the clutch 19 may be disengaged by throwing the pin 24 out into the position illustrated inFigure 16 which holds the clutch 19 open and stops the operation of the feeding roll 12 at the stack of sheets on the table 10. This is important in this machine because it permits the feeding of sheets from the stack or pile to be stopped while the remainder of the press A continues to operate as will be hereinafter more fully defined.

,The sheet conveying table 16 extends at an upward incline from the sheet feeding roll 12 and from the feeder rolls 1'7 which are positioned at the lower end of the conveyor table 16. The table 16 is provided with belt conveyors 25 which run along the surface of the table 16 on an angle inclined toward the adjustable grooved side guide 26 mounted upon the table 16. Positioned to cooperate with the conveyor belts 25, I provide a series of arms 2'? which are adjustably carried on the center supporting bar 28 and which have ball sheet contactors 29 in their outer ends positioned directly above the belts 25 so as to bear against the sheets carried by the conveyor belts 25 and hold the same against the conveyor belts by the weight of the balls 29. This guides the sheets along the belts 25 and holds the same in frictional contact therewith so that owing to the angular travel of the belts 25 from one end of the table to the other and in a direction toward the grooved side guide 26, the sheets carried by the belts 25 will be brought into registry or gauged relation with the bar 26 to automatically adjust the sheets in their travel from the table 10 along the conveyor table 16 to cause the same to be carried up against the grooved side guide 26.

As the sheets are carried by the conveyors 25 into the press A they are carried up against the notch 30 in the fingers which are rotatably carried upon the shaft 32. When the sheets to be lithographed are carried by the conveyor belts 25 along the table 16 they are brought up against the rotatable fingers 31 when the fingers 31 are in the dotted position illustrated in Figure 8. These fingers stop the sheet momentarily gauging it for forward position while the grooved side guide 26 gauges the sheet for side position and as the sheets reach this position against the fingers 31, a pair of. sheet holding fingers 33 which are carried by the pivoted link 34 depending from the supporting arm 35 come into contact with the sheet to firmly hold the same in place. The arm 35 is operated by the

levers

36 and 37 which connect with the operating lever 38 and which are operated by the cam 39 as illustrated in Figure '7. The cam 39 is -micrometrically adjusted upon the shaft 123 so that the operator may more accurately and easily set the operation of the fingers 33. This is accomplished by the micrometer-yoke 124 which operates the cam 39 to set the same by means of the ach'ustment of the micrometer screws 125.

The shaft 32 which carries the rotatable fingers 31 is operated by the levers 40-'and 41 and which in turn are operated by the cam 42. A spring 43 holds the operating levers for the fingers 33 while the spring 44 holds the operating levers for the fingers 31 in normal position. The earns 39 and 42 operate these fingers automatically in the operation of the machine.

The fingers 33 have an arcuated engag g surface 45 which engages against the sheet held on the table 16 in registry with the fingers 31 and the pivoted link 34 which supports the fingers 33 permits the fingers 33 to arcuate slightly as soon as the sheet which they are engaging begins to be moved oif of the table 16 after thefingers 31 have been turned out of operative position. These fingers 33 perform an important function in holding the sheets to be lithographed against movement after the sheets have been properly registered on the table 16 so that it is impossible for the sheet to getout of registry.

/istered upon the tabIe and held positively in position by the finger. s\33, the gripping fingers 46 carried by the impfiession cylinder 47 are brought into operation to engage the edge of .the sheet projecting beyond the inner edge 48 of the table 16 and at a period just aft r the fingers 31 have been rotated into the positiondllustrated in full lines in Figure 8. When the fingers 46 engage the sheet to carry the same arouhd the impression cylinder 47 in its operating rotation. the fingers 33 do not disengage until the sheet has been pulled forward slightly by the fingers 46 causing the fingers 33'to move arcuately just momentarily and then the fingers 33 are released and the sheet such as B is carried into position to be lithographed as the cylinder 47 rotates in the operation of the press A.

In the course of rotation of the impression cylinder 47, the sheet B is released from the grip of the fingers 46 when these fingers are caused to rotate away from gripping position as illustrated in Figure 12. These fingers 46 are operated by the cam 49 located at one end of the cylinder 47 so as to operate the'segmental gear 50 which operates the gear member 51 mounted upon the shaft 52 which supports the fingers 46. This operating means causes the fingers 46 to rotate freely and quickly away from the surface of the impression roll 47 thereby quickly freeing the sheet and carrying the fingers 46 to a position within a recess 53 formed-in the cyl-. inder 47. The fingers 46 remain in this position until just prior to engaging with the sheet from the edge 48 to grip the same onto the cylinder 47. By this construction, I provide a'positive release for the sheets B to discharge the same onto the sheet receiving fingers 54, between which the fingers 46 rotate in their releasing operation. The sheets are further released from the cylinder 47 by means of the ejecting pins 55 carried in the cylinder 47 and operated by the lever 56 which rotates with the shaft 5'7. The shaft 57 is operated by the lever 58 which engages the cam 59 to operate the ejecting pins 55 into the position illustrated in Figure 12. The cam 59 is located on the opposite end of the cylinder 47 to the cam 49.

This provides a positive release for the sheets I B even though the cylinder 47 rotates rapidly and causes the fingers 46 to move away from the line of travel with the discharge of the sheet B.

The impression cylinder 47 is mounted in the sides of the frame of the machine A and adapted to be held vertically adjustable by the bearing boxes 60 which are readily adjusted by the screw members 61. Directly in line with this cylinder 47 I provide the plate cylinder 62 which is supported in the vertically adjustable bearing boxes 63 by the operating screw members 64. Thus the impression cylinder 47 "and the plate cylinder,62 may be adjusted vertically in the press A when it is desired to properly set them into operative position.

Interposed between the

cylinders

47 and 62 and horizontally slidably mounted to permit antomatic releasing, I provide the blanket cylinder 65 supported in the bearing boxes 66 carried in the sides of the frame of the machine A. This blanket cylinder is positioned in relation to the

cylinders

47 and 62 so that it may be moved into operative position to contact with the plate carried on the cylinder 62 and to lithograph onto the sheet carried by the cylinder 47 the impression desired. The bearing boxes 66 contact with by the shaft 73.

the rods 6'7 upon which coil springs 68 are mounted, while the outer end of the rods 67 slide freely through the openings 69 in the frame of the machine A. Thus the springs 68 tend to urge the bearing boxes 66 to carry the blanket cylinder 65 away from the

cylinders

47 and 62.

I provide a locking means C to hold the cylinder 65 in operative position with the

cylinders

47 and 62 which includes the links '70 pivotally connected at '71 to the bearing boxes 66 which are adapted to be operated by the levers '72 carried Suitable bearings 74 are provided on the frame for supporting the shaft 73 and by means of a hand lever 75 the locking means C may be operated when it is desired to move the cylinder 65 into and out of operative position. When the links and thelevers 72 are positioned in line as illustrated in full lines in Figures 5 and 11, the cylinder 65 is locked in operative position to engage with the

cylinders

47 and 62.

I provide an automatic releasing means D to disengage or throw the cylinder 65 out of operative position when it is desired which includes a trip lever '76 pivotally mounted at 77. The lever 76 is formed with a notch end 78 which is adapted to be engaged by the lever 79 depending from the shaft 73. The compression spring means 80 engages the lever 79 tending to normally urge the same downward. When the looking mechanism C is moved by the hand operated handle into operation to set the cylinder 65 in operative position, the free end of the lever 79 will engage in the notch '78 as illustrated in Figure 10, which will slightly elevate the outer free end 81 of the lever 76. This free end 81 of the lever 76projects toward the front of the machine A, as illustrated inFigure l and provides a suitable means to permit the operator of the machine A to raise the same as illustrated in the dotted out ine in Figure 10, sufficiently to release the free end of the lever-79 from the notch 78 when it is desired, whereupon the springs automatically operate the shaft 73 to release the locking mechanism C. I

The tripping mechanism D is provided with a tripping plate 82 whichis pivotally mounted at 83 on the block 84 which, is mounted upon the shaft 77. The free end 82 of the tripping plate 82 is free to raise up when a sheet to be lithographed travels along the table 16 and under the free end 82'. However, should a sheet fail to be carried along the table 16 in a manner to raise 82, then the reciprocating lever 85 which is reciprocated back and forth by the cam 86 in the machine A will'engage against the free end 82' and push the trip plate 82 back in a manner to rotate the shaft 77 sufficiently to raise the tripping lever 76 so that the lever 79 will disengage from the notch '78, automatically tripping the locking mechanism C and releasing the cylinder 65'.

The machine A is automatically stopped by the operation of the electric switch 87 which is connected to the tripping mechanism through the shaft 73 in a manner so that the switch 87 will turn off the current to the motor 88. Thus when the tripping mechanismD is operated and the locking mechanism C is released, the motor for operating the machine A is simultaneously stopped, thereby immediately stopping theloperation of the machine A. This tripping 'r'neans such as D and'the operation of the blanket cylinder 65, I believe is a new structure in the construction of lithographing presses which is adaptand hold elevated the free end 82' of thetrip ed to operate in a simple and effective manner to release the blanket cylinder out of operating position and to simultaneously stop the operation of the machine A. There are no complicated parts or detail members which will be apt to get out of order or which will change the operation or registry of the machine A. The tripping mechanism is positive in operation and automatically stops the mechanism without effecting the setting or adjustment of the parts.

0 The machine A is provided with a moistening and inking unit E which is mounted on the frame of. the same directly above the plate cylinder 62 and has a series of ink distributing rollers 89 which are adapted to carry the ink from the ink fountain to the plate cylinder 62. The ink fountain 90' together with the ink distributing rolls 89 and the moisture rolls 90 are carried in the sides 91 of the unit E. This entire unit is pivotally mounted at 92 in the frame of the machine A and is adapted to be operated by means of the link rods 93 which are connected to the links 94 and adapted to be operated by the shaft 95 when the lever 96 rotates the shaft 95 in a manner to raise the unit E on one end thereof sufficiently to raise the ink distributing and moisture rolls away from the plate cylinder 62. This structure is illustrated in- Figures 3, 5 and 6. The lever 96 operates in conjunction with the quadrant 9'7 so that the spring pin 98 carried by the free end of the lever 96 is adapted to engage in openings such as 99. formed in the quadrant to lock the unit E either in operating or inoperative position.

In the operation of the machine A it is only necessary for the operator to engage the free end of the lever 96, disengage the pin 98 from one- 0f the openings 99, and press down on the lever 96, and this will raise the link rods 93. thereby raising the unit E as illustrated in Figure 6, away from the plate cylinder 62. The rollers of the unit E may continue to operate ,with the-operation of the machine even though they are elevated, and' thus they maintain the proper distribution of the ink and moisture on the rolls in the unit E so that they maybe instantly brought into operative relation with the cylinder 62. The unit E moves but slightly. This slight movement is sufficient to space the unit from the cylinder 62, but is not sufficient to disengage the unit from the driving gears, so that the unit E continues to operate when in the position illustrated in Figure 6. I have found this feature very desirable in the operation of my lithographing press A. j

Certain rollers of the unit E are adapted to be oscillated by the cam 100, as illustrated in Figure 2. which raises the link 101 up and down to oscillate the shaft 102, and the shaft 102 in turn oscillates the levers 103 and 104. The shaft 103 is provided with a roller 105 on the end which engages between flanges 106 to oscillate the shaft 107. The lever 104 is provided with a roller 108 which operates between the flanges 109 to oscillate the shaft- 110 and by means of the link inking and moisture units, insofar as I know,

the method of operating the rollers of the unit E to oscillate the same as just described, I believe has never been ,done, and particularly in conjunction with the pivoted unit E which may be elevated away from the plate cylinder and may continue to operate so that the ink and moisture carried by the unit E is evenly carried through the unit being constantly worked to keep the same in readiness for immediate operation as soon as the lever 96 is operated to release the unit E into operative posit-ion with the plate cylinder 62.

The lithographing press A is provided with a micrometrically adjustable gauge F which is positioned above the .table 16 and is provided with a gauge bar 117 pivotally supported at 118 and adapted to be adjusted by the

set screws

119 and 120. The

screws

119 and 120 may be adjusted to micrometrically set the arcuated edge 121 in relation to the table 16 so that only one sheet at a time may pass beneath the edge 121 into registry to be engaged by the gripping fingers 46. The tripping plate 82 is positioned in the table 16 beyond this gauge F so that should any sheets pile up at the gauge bar 11'? thereby preventing the sheets from passing beyond the gauge, the machine will be automatically tripped to stop the same.

The lithographing machine A has been designed and operated to carry out the principles set forth so as to provide a machine of this character which may be easily operated and maintained in lithographing sheets in a practical manner.- thoroughly tried and tested in actual operation and have been found to provide advantages over structures used heretofore in lithographing presses. My lithographing press A will operate to maintain registry I believe more accurately and provides a simple structure with fewer parts which may be readily and easily adjusted. In the operation should it be desired to stop the feeding of sheets off of the table 10, it is only necessary for the operator to disengage the clutch 19 permitting the remainder of he machine to continue to operate so as to carry any sheets which are already in the press on through the same. This permits the sheets to be cleared out of the machine.

During the operation of the machine A, either the absence of a sheet in the press to be carried to the impression cylinder or the lifting of the tripping lever '76 by the operator will cause the blanket cylinder 65 to be automatically released out of operating position, thereby preventing overinking of the blanket or getting ink on the impression roll. The absence of the sheet in the machine to be lithographed may stop the entire machine simultaneously with the releasing of the lock C or the operating parts of the electric switch 8'7 which controls the operation of the machine A may be set so as not to be operated by the releasing of the cylinder 65, permitting the machine to continue to operate after the cylinder 65 has been released out of operating position. Further, the operator may elevate the inking and moisture unit E at any time yet permitting theparts of the unit to continue to operate the rolls of the same without contacting with the plate cylinder 62, keeping the ink and moisture in this unit ready for instant operation. These features are of primary importance in the operation of my lithographing machine A.

In accordance with the patent statutes, I have described the principles of operation of my litho- All of the features set forth have been graphing press and while I have illustrated a 1 from the spirit of the invention and within the scope of the following claims.

I claim:

l. A lithographing press including, a plate cylinder, an impression cylinder, means for adjusting said cylinders vertically, a blanket cylinder associated with said plate and impression cylinders and en ageable therewith, means for looking said blanket cylinder in operative position with said plate and impression cylinders, means for releasing said blanket cylinder, and springmeans for automatically moving the same simultaneously an equal distance out of engagement with said plate and impression cylinders.

2. A lithographing press including, a plate cylinder, an impression cylinder for receiving sheets to be lithographed vertically aligned with said plate cylinder, a blanket cylinder, said plate and impression cylinders being adjustable vertically, means for horizontally sliding said blanket cylinder into operative position with said plate and impression cylinders, means for locking said blanket cylinder into operative position, spring means for moving said blanket cylinder out of operative position, and tripping means for releasing said locking means for said blanket cylinder operated by the absence of a sheet to be lithographed in said press.

3. A lithographing press including, a plate cylinder, an'impression cylinder, a blanket cylinder interposed in a manner to be slid into and out of operation with said plate and impression cylinders simultaneously while said plate and impression cylinders remain operatively fixed, means supporting said blanket cylinder slidable substantially normally to a plane through the axes of the plate and impression cylinders, means for adjusting said plate andimpression cylinders to register with the blanket cylinder when said blanket cylinder is in operative position, means for locking said blanket cylinder in operative position, and spring 'means for pushing said blanket cylinder out of operating position when said locking means is released:

4. A lithographing press comprising, a frame. a plate cylinder, an impression cylinder, an inking and moisture unit associated with saidplate cylinder, inking and moisture rollers in said unit, means for lifting said unit out of operative contact with said plate cylinder, and means for rotatably engaging each of said rollers to rotate said rollers when in or out of contact with said plate cylinder.

5. An offset lithographing press including, a frame, a plate cylinder, an impression cylinder, an ink feeding and moisture unit associated with said plate cylinder, means for pivoting said unit to said frame, and means for elevating said unit out of contact with said plate cylinder and means for operatively connecting the parts of said unit in or out of contacting position.

6. The combination, a printing press, a frame, a-plate cylinder, an impression cylinder, sheet gripping fingers carried by said impression cylinder, vertically adjustable bearings supported in said frame, means for adjusting said hearings in said frame to adjust the position of said plate and impression cylinders in relation to each other, a blanket cylinder, slidable bearings positioned ,in said frame for supporting said blanket cylinders and locking means for forcing and holding said blanket cylinder operatively contacting with said plate and impression cylinders.

7. A lithographing press including, a rotary stop for retarding each sheet in its passage to the press, fingers for engaging the sheet simultaneously with the engagement with said rotary stop adapted to hold the sheet stationary in proper registered position within said press, means for operating said rotatable stop out of operative position, an impression cylinder, means for gripping the sheet to draw the same over said impression cylinder, said sheet engaging fingers having an oscillatory movement to move with the sheet slightly before disengaging therefrom as the same is drawn on to the impression cylinder.

8. A lithographing press including, an impression cylinder, gripping fingers carried by said cylinder, means for rotating said gripping fingers into andout of operating position, a recess into which said fingers are adapted to be embedded when out of operating position formed in said inder, an impression cylinder, an offset blanket cylinder, means for slidably supporting said blanket cylinder to be operated into and out of simultaneous engagement with said plate and impression cylinders, a member continuously moving with the press, and trip means pivotal. into position to be engaged by said member in the absence of a sheet in said press to be lithographed on to automatically trip said offset blanket cylinder out of operative position.

10. A lithographing press comprising, a plate cylinder, an impression cylinder, a-blanket cylinder interposed between the mounting points of said plate and impression cylinders and .having its bearings slidably supported oifset from the bearings of said plate and impression cylinders, spring means for urging the bearings of said blanket cylinder to move the same away from said plate and impression cylinders simultanei ously, locking means for holding said blanket cylinder operatively against said plate and impression cylinders, sheet feeding means] in said press, trip means interposed in the path of travel of the sheet in said sheet feeding means, means I engageable with said trip means in the absence 1 11. A lithographing press including, oifset .lithographing means, means for driving said lithographing press, means rendered inoperative by the presence of a sheet being fed to the press for releasing the oifset mechanism of. said press out of contact with the remainder of said lithographing means, and means for simultaneously stopping said driving meansfor said press.

12. A lithographing press including, a plate cylinder, a blanket cylinder, an impression cylinder, said blanket cylinder being slidably positioned to be operated" into and out of contact with said plate and impression cylinders, m ans for locking said blanket cylinder to contact with said plate and impression cylinders, electrical means for operating said press, an electric switch for controlling said electrical operating means, a sheet controlled tripping means including means for simultaneously tripping said blanket cylinder out of operating position and to stop said electrical operating means in the absence of a sheet in said press to be lithographed. 13. A lithographing press including, an ofiset cylinder having blanket, plate and impression cylinders, means for holding said oiiset cylinder locked into operative position with said plate and impression cylinders, spring means for pushing said offset cylinder at an equal angle away from said plate and impression cylinders simultaneously when said lock is released, and hand operated tripping means for releasing said lock to automatically release said oilset cylinder out of contact with said plate andimpression' cylinders. 14. A lithographing press including, plate and impression cylinders, means for vertically adjusting and supporting said cylinders in axial alignment, an offset blanket cylinder horizon tally slidably supported to one side of the axial alignment of said plate and impression cylinders, means for locking said blanket cylinder in contact with said plate and impression cylinders, spring means for urging said blanket cylinder simultaneously out of operative position with said cylinders, hand operated lever means for setting said locking means in operative position, a sheet feeding conveyor and table, a sheet trip positioned within said table for tripping said locking means, and a reciprocating lever engageable to operate said trip in the absence of a, sheet to be lithographed to release said blanket cylinder out of operative pwition by said spring means.

15. A lithographing press including, a lithographing means for sheets, means for feeding and registering sheets in said press, a trip to release said lithographing means out of operative position adapted to be operated by the sheets fed into said press by said sheet feeding means, a

reciprocating lever for operating said trip, said trip being pivotally mounted to be held elevated out of tripping position with said reciprocating lever when a sheet is disposed on said sheet feeding means.

offset cylinder in operative position, and means for moving said offset cylinder out of operating position automatically by the absence of a sheet at the moment of registration in said press including a continuously moving member anda trip engageable with said member in the absence of a sheet.

17. A lithographing press including, an offset blanket cylinder, means for slidably mounting said blanket cylinder, means for locking said 011'- set cylinder into operative position, spring means for moving said blanket cylinder out of operative position,'a plate cylinder, an impression cylinder, means for adjusting said plate and impression cylinders to contact with said blanket cylinder when the latter is locked in operative position, means for automatically releasing said blanket cylinder simultaneous out or engagement with said plate and impression cylinders by the absence of a sheet in registered position in said press, and means for independently operating said releasing means of said sheet operating means by hand by the operator of said press.

18. A lithographing press including, plate, im-

pression and offset cylinders, means for locking said offset cylinder into engagement with said plate and impression cylinders, spring means for throwing said oflset cylinder out of operative position when said locking means is released, said locking means including a trigger member, means for holding said triggerunder spring tension, a reciprocating lever, means on said holding means engageable by said reciprocating'lever .to release said trigger, said last named means rendered ordinarily inoperative by the presence of a sheet of paper between this means and said reciproeating lever.

19. A lithographing press including, plate, impression and blanket cylinders, means for releasing said blanket cylinder from engagement with said plate and impression cylinders including, a trigger operable to release said blanket cylinder, means for holding said trigger under spring tension, a reciprocating lever, and means on said holding means for engagement by said reciprocablelever when a sheet is not fed to the press to trip said trigger and. to release said blanket cylinder.

20. A lithographing press including, cylinders, means for removing one cylinder from operative position, and for holding said cylinder in operating position, means comprising a pair of pivoted toggle levers pivotal into longitudinal alignment to hold said cylinder in operative position and pivotal into relative angularity to release said cylinder.

' ,WILLIAM ROY HOTCHKISS.