US2067199A - Blockout mechanism for duplicating machines - Google Patents

Description

Jan. 12, 1937. MARCHEV 2,067,199

BLOCKOUT MECHANISM FOR DUPLICATING MACHINES Filed Jan. 10, 1936 8 Sheets-Sheet l 8 Sheets-Sheet 2 Jan. 12, 1937. A. MARCHEV BLOCKOUT MECHANISM FOR DUPLICATING MACHINES Filed Jan. 10, 1936 a XE Jan. 12, 1937. A. MARCHEV BLOCKOUT MECHANISM FOR DUPLIGATING MACHINES Filed Jan. 10, 1936 8 Sheets-Sheet 3 Jan. 12, 1937. A. MARCHEV BLOCKOUT MECHANISM FOR DUPLICATING MACHINES Filed Jan. 10, 1936 8 Sheets-Sheet 4 Jan. 12, 1937. A. MARCi-IEV' BLOCKOUT MECHANISM FOR DUPLICATING MACHINES Filed Jan. 10, 1936 8 Sheets-Sheet 5 Jan. 12, 1937. MARCHEV 2,067,199

BLOCKOUT MECHANISM FOR DUPLICATING MACHINES Filed Jan. 10, 1936 8 Sheets-Sheet .6

jmvgefy Jan. 12, 1937. A. MARCHEV 2,067,199

BLOCKOUT MECHANISM FOR DUPLICATING MACHINES Filed Jan. 10, 1936 8 Sheets-Sheet 7 Patented Jan. 12; I

UNITED STATES PATENT "O-F-FIICE BLOCKOUT MECHANISM FOR DUPLI- CATING MACHINES Alfred Marchev, La Grange, Ill., assignor to Ditto, Incorporated, Chicago, 111., a corporation of West Virginia Application Januarylo, 1936, Serial No. 58,523

is Claims. (o1. 191 -132) This invention relates to duplicating machines master sheet receiving position with the old and'is particularly adapted, to be embodied in a master sheet still in place and apply a block-out duplicating machine wherein copy sheets are sheet or a new master sheet, or leave the old brought into contact with a master sheet, a suitmaster sheet undisturbed as he may desire.

5, able solvent for the ink or carbon on the master Other features and advantages of the invention sheet being employed so that the data on the will become apparent as the following description master sheet will be transferred to the copy sheet. progresses, reference being had to the accom- The master sheets have the data to be duplipanying drawings whereincated formed thereon in reverse so that, when a Fig. 1 is a plan view of a duplicating machine portion of the carbon or ink is dissolved off by which embodies the invention; 10 the volatile fluid and transferred to the surface Fig. 2 is a vertical sectional view taken subof the copy'sheet, it will appear in correct readstantially on the line 2-2 of Fig. 1;

able form. Fig. 3 is a sectional view taken substantially According to one type of machine to which on the line 3-3 of Fig. 1;

this invention is applicable, a volatile solvent Fig. 4 is afragmentary sectional view taken on 15 such as alcohol is employed, and this solvent is the line 22 of Fig. 1 showing'a changed posiapplied to the surfaceof the copy sheets as they tion of the mechanism from that illustrated in approach the master sheet so that the master Fig. 2; A sheet and copy sheet may be placed in intimate Fig. 5 is a fragmentary sectional view taken contact before the solvent has had time to on the line 2--2 of Fig. 1 showing the mechanism 20 evaporate. v in a further position; i

Certain forms of the invention are embodied Fig.. 6 is a fragmentary sectional view taken in a machine of the type shown and described in on the line 2-2 of Fig. 1 showing the mechanism' the application of John W. Hernlund, Serial No. in a further position;

44,911, filed October 14, 1935, for Duplicating Fig. 7 isa fragmentary sectional-view taken on machines. This machine comprises a rotary the line 2-2 of Fig.1 showing a further position drum having means for clamping master sheets of the mechanism;

thereto and for discharging them therefrom. Fig. 8 is a'fragmentary plan view of a portion The copy sheets may be advanced to the drum in of the mechanism;

any suitable manner, and a platen roller is adapt- Fig. 9 is a fragmentary sectional view similar 30 ed to press the copy sheets against the master to Figni showing a modified form of the invensheet during the duplicating operation. Moistention; 1 ing means and copy sheet advancing means com- Fig. 10 is a fragmentary sectional viewlike prises combined moistening and feeding rollers Fig. 9 showing the modified parts in a difierent adjacent the drum and operated in timed relaoperative position; 1 i

tion' thereto for advancing the copy sheet to the Fig. 11 is a fragmentary sectional view like platen roller and drum and at the same time ap- Fig. 9 showing the 'modified parts in a; third plying the necessary solvent to one surface of the position; j copy sheet to dissolve ink from the master sheet Fig. 12 is a fragmentary plan view ofthe n'io'di- 40 upon the drum. fied form of the invention; and l 40 The improved machine herein disclosed com- Fig. 13 is afragmentary plan view of a part] of prises means whereby the master'sheet may be the mechanism shown in Fig. 12, certainparts attached to and removed from the drum, and being in section to illustrate the structure ,more means whereby block-out sheets for preventing clearly; a r

transfer of a certain portion of the copy on the Fig. l4'is afragmentary sectional view show- 45 master sheet may be superimposed and held upon ing a further modification. I 1 V 3, the master sheet at the will of the operator. Referring now in detail to the drawings,

Means are also provided whereby the operator which a preferred embodiment of the'invention is may control a master sheet laying tray so as to shown, reference characters I! and'l5fdesignate;

bring it into registry with master sheet gripping a pair of side frames adapted to rest upon any .50 means on thedrum at a stationary position of the. suitable support, these sideframes l4 and lSTbe-Q vgripping means. ing provided with rubberlfeet lt and L1,,The

Means are also provided whereby the operator side frames are suitably ls 'ecure d together by may, by a simple movement of a control. lever, brackets, not shown. A'duplicatingdrun lll is release amaster sheetor stop the drum-in the supported from the side frames by afsh'aft' 19,65

A moistening receptacle 22 is provided with a moistening felt or wick 23 adapted to supply moisture to a combined feeding and moistening roller 24. A second roller 25 cooperates with the roller 24 in feeding copy sheets to the drum l8. For

pressing the copy sheets against a master sheet on the drum, a platen roller 26 is carried by the side frames of the machine in a manner more fully described. in the-application hereinbefore identified.

The details of the'moistening mechanism and copy sheet feeding mechanism form no part of the present invention and hence will only be described generally in order to enable one to understand the applicationof the present invention to a machine of this type.

The platen roller 26 is not independently driven, but is rotated by its contact with the drum I18 or with sheets interposed between it and the drum I8. A gear 21 is secured to one end of the drum l8 and drives an idler gear 28 which in turn drives a gear 29 fixed to the moistening roller 24. The moistening roller 24 is thus driven in timed relation to the drum, and its cooperating roller 25 is driven by contact with the roller 24 or a sheet of paper interposed between the rollers.

The drum I8 is adapted to be intermittently driven, as disclosed in the prior application, from a suitable source of power not shown. The mechanism whereby the rotation of the drum I8 is accomplished comprises a driven shaft 30, a, pinion 3| thereon, and a gear 32 journalled upon "the shaft 19. As is more fully described in the prior application, the gear 32 has connected therewith, by suitable yielding connections 33, a ratchet wheel 34 which is adapted to be connected at intervals to a pawl 35 carried by the drum l8.

The pawl 35 is pivoted by a pin 36 to the drum -and is backedup by a cushioning member 31 which is mounted upon a bracket 38, as will be readily understood. ,A stop block 39 is also carried on the drum. The block 39 is pivoted on the pin 36 and held between the member 31 and a pin 39. The stop block 39 is directly behind the pawl 35, as shown in Fig. 3. The pawl 35 has a tooth 48 which is adapted to engage with an abutment 4| yieldingly-supported upon a trip arm 42. The pawl 35 and the associated parts 36, 31, 38. 39, and 39' are all secured to the drum by means of a plate 43 which is adjustably secured to one end of the drum by means of a pair of bolts 44 and 45 working. inelongated slots in the plate 43. it being understood. of course. that the plate 43 is apertured. to receive the shaft l9 and turns about this shaft as an; axis in adjusting the plate 43 relative to the drum. The purpose of the adjustable mounti'ngofi plate 43 on the drum I8 is for setting the drum and its master sheet gripping mechanism with respect to. the stop member 39 to obtain proper margins upon the copy sheets. This mechanism. and? its; purpose are more clearly explained in. the prior application andwill not be further referredlto.

The pawl 35 isyiel'dingly pressed toward engagement with the ratchet wheel 34 by a spring 46 secured tothe pawl 3.5:by a pin 41 and secured to the plate 43 by a pin. 48. In the stationary position of the. drum, the pawl is lifted out of engagement. with. the ratchet wheel 34 by the portion 48' engagingtthe stop 41 on thetrip lever 42. as hereinb'ef'ore described. This trip lever 42 is pivoted upon a; stub shaft 49 mounted. on the .55 on the latch The trip lever 42 has a projection 53 which is provided with a pin 54 adapted to engage a finger lever 58 so that, when the trip lever 42 is lifted out of engagement with the portion 48 of the pawl 35, the pin 54 pressing upon the finger 55 will lift the latch lever 58 inorder to prevent its striking the plate 43 in the subsequent rotation of the drum. A spring 56 is connected to the trip lever 42 by a pin 51 and is connectedto the side frame [4 by a pin 58. A spring 59 is interposed between a shoulder 68 on the trip lever 42 and the latch lever 50 so as to urge the latch lever in a direction to bring the finger 55 against the pin 54. The trip lever 42 is actuated by a cross bar 6! which is supported at one end by an arm 62 pivoted at 63 to the side frame 15. At its other end, the cross bar 6| is connected to the trip lever 42 by a lever arm 64 which is secured by a pin 65 to a hub 66 for the trip lever 42. A stop pin 61 is mounted on the side frame 14 to limit the upward movement of the lever arm 64.

As shown and more fully described in the prior application hereinbefore mentioned, the hub 66 has a depending arm 68 which is connected by a pin 69 to a link 18, the pin 69 riding in a slot 1| of the bar 10. The link 10 links the trip lever 42 and its associated mechanism with a second set of trip and latch levers for controlling the positioning of the drum for replacement of master sheets. The link 18 is pivoted to an arm 12, which is bifurcated to receive the link 10, and has a pin 13 for securing the link 18 thereto. The arm 12 is fixed upon a shaft 14 which is journalled in the side frames l4 and I5. Adjacent the arm 12 the shaft 14 has pivoted thereon a. trip lever 15 and a latching lever 16 which are substantially duplicates of the trip lever 42 and latch lever 58. The latch lever 16 is connected to the trip lever 15 by being pivoted on the same axis,

and a limited amount of movement of the latch bracket 82 on the side fram'e I5 is adapted to engage a pin-83 upon the trip lever 15 to limit the inward movement of the latch lever and trip lever.

The trip lever 15 is connected to the shaft 14 upon which it is pivoted by means of a coiled spring 84 which at one end is connected to a pin 85 on a' projection 86 which is formed on a hub 81 for arm'12 which is fixed to the shaft 14. The other end of the coiled spring 84 is secured to a pin 88 which is mounted upon the projection 80. The direction of winding the coiled spring 84 causes it to urge the trip lever 15 toward positionto engage the stop portion 48 of the pawl 35. Thus the trip lever 15 and its latch lever 16 are used to stop the drum ceiving position as more clearly explained in the prior application. hereinbefore mentioned.

The mechanism for operating trip lever 15 and latch lever 18 in. master sheet re- 16 comprises a bifurcated arm energies the machine from the mechanism just described.

The bifurcated arm 96 extends from a hub 9| that is also provided with a cam projection 92, the purposeof which will be more fully explained hereinafter. The bifurcated arm Qt is connected by a link st to a bifurcated projection 9% upon a hub d of a hand lever t6. The hand reverts is pivoted by means of the hub 95 to rotate about the shaft it. The hub Q5 carries a pair of rollers @l and 9% which rollers are adapted to operate a pair of spreading cams 99 and Ill. These cams t9 and its are pivoted upon stub shafts lol and W2 suitably mounted on the side frame it. A spring 193 coiled around the hub of the spreading cam 99 with one end fixed to a pin it on the spreading cam and the other end fixed to the frame it operates to urge the spreading cam til against the roller 9?. A similar spring I35 on the hub of the spreading cam ltd and secured to the spreading cam by a pin 1%, operates to urge this cam towards its roller 98.

The hand lever 96 maybe placed in any one or the positions shown in Figs. 4, 5, and 6. When in the position shown in Fig. 6, the hand lever 96, through the medium of the link 33, positions the bifurcated arm 98 as shown in Fig. 6, and this so positions the shaft it to release the spring 86 and to move the trip lever l5 and the latch lever 16 out of the path ofthe pawl portion til and the plate 33. This is normal operating position for making copies on the machine.

Now, however, when the handle at is moved into the position shown in Fig. 2 and Fig. 4, the spring 85 pulls the trip lever l5 and its corresponding latch lever it into position to engage the pawl portion as the drum rotates. When the portion d of the pawl 35 engages the stop portion of the trip lever l5, the drum is stopped in the position shown in Fig. 4 and held against rotation by the levers i5 and it. It will be noted from an inspection of Fig. i thatroller 97 engages in a depression ill in the cam dd while roller 98 engages a depression 38 in the cam arm Hi0.

Cam arms 99 and Edit are adapted to cooperate with a gripper control lever ids which is keyed on a gripper shaft its that is mounted in the drum it. Suitable gripper fingers ii i, more fully described in the prior application, are secured upon the gripper shaft HQ and areadapted to grip a master sheet M2 against a. surface Ht formed in the periphery of the drum. The arm iiltl carries a roller Ht which is adapted to ride upon the cams 9t and ltd when they are spread out into the path of this roller. A spring it, connected to the free end of the arm 9G9 and attached to the drum, acts to hold the arm its in position to close the grippers ii i except whentray 28, the rollers iii and til being located in the depressions it]? andibd of the spreading cams es and we do not engage the roller ti l .so as to open the ,gripmrs ill. .l-Iowever, if the hand lever 98 is moved frorn the position shown in Fig.

4 to the position shown in Fig. 5, therollers 9i and Q8 are moved out or their respective seats .at it? and idil in the spreading cams and spread these cams so that the cam ltd is lifted against the roller ti t causing counter-clockwise movement or the arm its, as shown in Fig. 5, and a resultant opening of the gripper i i I. If the hand lever is then returned to the position shown in Fig. 4, the grippers iii will again be closed due to the pull of the spring H5 upon the arm I09. Thus it is possible to bring the drum it to a stop without opening the grippers ii in a position to align the gripping mechanism with the master sheet tray 28 and, as pointed out, the grippers iii may then be opened and closed without releasing the drum for further rotation since the gripper opening movement is accomplished by movement in a direction which tends to hold the levers l5 and it in their drum stopping position.

In the normal operation of the machine, it is not necessary to stop the drum in alignment with the master sheet tray without releasing the used master sheet, so the operator, when he desires to replace the used master sheet, moves the hand lever 95 into the position shown in Fig. 7. This causes the roller 91 to move out the spreading cam 99 and, when the roller H5 rides over the spreading cam 99, it opens the grippers iii in the manner indicated in Fig. 7 and releases the old master sheet. The drum, however, continues to rotate until it is stopped by the levers l5 and it engaging with the pawl portion 40 and the notch in the plate t3, respectively. At this time, that is at the time the drum comes to rest, the roller ti t is riding upon the surface of the spreading cam Hit and the grippers H l are held in open position to receive a fresh master sheet. 7

It is often desirable to insert a sheet over a portion of the master sheet for the purpose of preventing the transfer of the data on that portion of the master sheetato a copy sheet. Since there is no adherence between a block-out sheet and master sheet used in'this type of machine, it is necessary to secure the block-out sheet by some means. The present invention provides mechanism whereby a block-out sheet may be superimposed upon a master sheet H2 without disturbing the position of the master sheet.

The master sheet tray 2b is pivotally mounted rodiit. A spring Mil, secured at one end to the master tray 2 by a pin H8 and secured at its other end to a bar M9 on the side frame E5 of the machine, tends to tip the master tray 20 toward the drum it. The master tray has a plate 2d secured to the under surface thereof and provided with a plurality of spring fingers 62. These fingers 62E are adapted to engage the master sheet 6 H2 in the manner illustrated in Fig. 5 when the tray 28 is permitted to move toward the drum suiiiciently topermit such engagement.

In the normal operation of the machine, however, the cam 92 mounted on the shaft i i is held in the position shown in Fig. 6 so as to engage against a stop 622 provided on a bar 123 which depends from one side of the master tray 29. At one end of the master tray 29, a supporting dish lid extends toward the drum i8, and the drum 58 has a notch are adjacent the grippers iii and in line with the disk 52d. Since the cam is connected to the shaft it, it is evident that,

. when the handle /er @G is moved-into the position shownin Fig. 7"to discharge a used master sheet, the master tray is will be pernntted to move toward the=drum because the-cam 92 is moved away from the stop member i22 which normally holds the master tray 2% in raised position. The disk 26 then rides upon surface of the drum close to the end thereof until the drum reaches with respect to the frame of the machine by a tie stop position with the master sheet grippers III aligned with, the tray 20. At this point, the disk I24 drops into the recess I25 as will be readily understood.

Now in the operation of the machine to place a block-out sheet upon the master sheet II2, the operator, instead of moving the-handle 96 all the way over to the position shown in Fig. 7,

moves it only to the position shown in Fig. 4 so that the grippers III are not opened by engagement of the spreading cam 99 with the roller II4. However, even this movement, of the lever 96 causes the cam 92 to move away from the stop I22 and pennits the tray 20 to tip toward the drum. The disk I24 stops the tray 20 before the fingers I2I can engage the master sheet II2. This action of the disk I24 prevents the fingers I2I from smearing the master sheet. When the drum arrives in stop position, the disk I24 is aligned with the recess I25 in the drum, and this permits the fingers I2I 'to engage the master sheet H2 and to hold it in place. The operator can then move the hand lever v96 to the position shown in Fig; 5 thereby opening the grippers III as shown in Fig. 5, and a block-out sheet I26 can be inserted without disturbing the position of the master sheet H2. The hand lever 96 can then be moved back to gripper closing or normal operating position.

As described in the application hereinbefore mentioned, the movement of the hand lever 96 back to normal operating position results in releasing the levers I5 and 16 thereby permitting the pawl 35 to engage the ratchet wheel 34 which causes the drum to rotate around until it is stopped by the trip lever 42. In this position, the drum is ready for normal operation of feeding copy sheets.

In Figs. 9 to 13 inclusive, a slightly different mechanism is shown for controlling the application of a block-out sheet. In this form of the invention, the hand lever 96 has pivoted thereon a bar I30 which bar has an elongated slot I3I that is engaged by a pin I32 mounted in the side frame I5. The master sheet tray 20 has apin' I 33 projecting from the side edge thereof over the bar I30 and adapted to ride on the top surface of this bar. The top surfaceof the bar I30 acts as a cam and is provided with a depressed portion I34, the purpose of which will presently appear. In the normal running position of the machine, the hand lever 96 is in the position shown in Fig. 11 so that the pin I33 on the tray 20 rides upon the high portion of the bar I30 and holds the tray 20 in raised position away from thedrum I8. I

Now when itlis desired to apply a block-out sheet over the master sheet held on the drum, the hand lever 96 is moved into the position shown in Fig. 9 where it sets the stop mechanism hereinbefore described to stop the drum with the gripper III aligned with the master sheet tray 20. The operator usually sets this handle 96 while the drum is stationary in copy sheet receiving position. He then taps the control bar 6| which releases the drum and permits it to rotate until it is stopped by the levers 15 and I6. It will be noted from Fig. 9 that the pin I 33 and the bar I30 hold the tray 20 raised away from the drum during the advance of the drum to this position. The operator then pulls the hand lever 96 over into the position shown in Fig. 10 which moves the bar I30 to the left as shown in Fig. 10 from the position shown in Fig. 9 and brings the lower portion I34 of the top surface sheet I26 is positioned beneath thegrippers III.

The grippers can then be'closed and the master sheet tray 20 raised by moving the hand lever 96 back to its normal operating position. This also allows the drum to rotate to its own position and the desired number of copies can be run oil by operating the front control bar 6| In many instances the operator may desire to make a few copies from a master sheet and then release it and save the master for future use. If the tray 20 were permitted to drop when the hand lever 96 is moved to release the master, the tray would smear the back end of a long master sheet.

To avoid this danger, a mechanism is. provided to lock the master tray .20 in raised position so that operation of the hand lever 96 will not effect movement of thetray to bring the fingers I2I against the drum. The tray may be locked by utilizing a pin I35 mounted in the side frame I and an aperture I36 in the side tion I31 which passes through a member I38- screw threaded into the side frame I5 and is provided with a knurled head I39. The member I38 has an enlarged opening I40 housing a spring I4I which urges the pin I35 toward the tray 20. The reduced portion I31 of the pin I35 has-a cross pin I 42 therein which cross pin may be aligned with a slot I43 in the member I38 0r aligned with a notch I44 in the outer end of the member I38. When the pin I42 is in the slot I43, the spring I4I presses the pin I35 toward the aperture I36 in the tray 20. 'When the pin I35 is withdrawn and turned a quarter .tum to align its cross pin I42 with the notch I44, the

the tray 20 is controlled by the bar I30.

In Fig. 14, a slightly modified form of mechanism is shown for controlling the actuation of the tray 20. In this form of the mechanism, a portion I45 of the side wall of the tray 20 is extended downwardly and is adapted to engage a pin I46 fixed upon a projection I41 that is integral with the bifurcated arm 90.

, While certain embodiments of the invention have been shown and described, it is to be understood that it is capable of many modifications. Changes, therefore, in the construction and arrangement may be made without departing from the spirit and scope of the invention as disclosed in the appended claims in which it is the intention to claim all novelty inherent in the invention as broadly as possible in view of the prior art. Having thus described the invention, what I claim as new and desire to secure by Letters Patent is:

1. In a duplicating machine, a rotatable drum, gripping means on said drum for securing the master sheet thereto, means for supplying copy clamp a master sheet on said a pressure roller for pressing copy sheets against the drum,

roller for pressing copy sheets against the drum,

means to open said gripping means while the drum is stationary, and master sheet holding means operable by said first named means to hold the master sheet in said gripping means against movement when said gripping means is open whereby a'second sheet may be inserted into said gripping'ineans over the master sheet. 4. In a duplicating machine, a rotatable drum,

gripping means on said drum for securing the master sheet thereto, means for supplying copy out sheet over said master sheet comprising holding means operable to hold the master sheet,

in posit-ion upon the opening of'said gripping means, said holding means comprising a member having a plurality of spring fingers for pressing the master sheet against the drum.

5. A duplicating machine comprising a frame,

a drum rotatable therein, gripping means to clamp a master sheet on saiddrum, a pressure roller for pressing copy sheets against the drum, means to open said gripping means while the drum is stationary, and means operable to hold a master sheet in said gripping means when said gripping means is open whereby a block-out sheet may be inserted in said gripping means without displacement of the master sheet,-said master sheet holding means comprising a plate mounted on said frame for movement toward-and away from saiddrum, and having means thereon for pressing the master sheet against the drum.

6. In a duplicating machine, a rotatable drum, gripping means on said drum for securing the master sheet thereto, means for supplying copy sheets to said drum, a pressure roller for pressing copy sheets against the master sheet on said drum, moistening means for supplying-a volatile solvent for the data on the master sheet and mechanism for supplying and attaching a blockout sheet over said master sheet comprising holding means operable to hold the master sheet in position upon the opening of said gripping means, and a hand lever for controlling said holding means.

7. A duplicating machine comprising a frame, a drum rotatable therein, gripping means to clamp a master sheet on said drum, a pressure roller for pressing copy sheets against the drum, means to open said gripping means while the drum is stationary, and means operable to hold a master sheet in sa d gripping means when said gripping means is open whereby a block-out sheet may be inserted in said gripping means without displacement or the master sheet, said holding means comprising a master sheet tray pivoted on said frame and having a member thereon for engaging the master sheet adjacent to said grippers.

8. A duplicating machine comprising a frame,

clamp a master sheet on said drum, a pressure roller for pressing copy sheets against the drum, means to open said gripping means while the drum is stationary, and means operable to hold a master sheet in said gripping means when said gripping means is open whereby a block-out sheet may be inserted in said gripping means without displacement of the master sheet, said holding means comprising a master sheet tray pivoted on said frame and having a member thereon for engaging the master sheet adjacent to said grippers, spring means urging said tray toward the drum, and manually controlled mechanism for holding the tray away from said drum.

9; A duplicating machine comprising a frame, a drum rotatable therein, gripping means to clamp a master sheet on said drum, :3, pressure roller for pressing copy sheets against the drum, means to open said gripping means while the drum is stationary, and master sheet holding means operable by said first named means to hold the master sheet in said gripping means against movement when said gripping means is open whereby a second sheet may be inserted into said'gripping means over the master sheet, said holding means comprising a plate, spring fingers plate on the frame. I

10. A duplicating machine comprising a frame, a drum journalled for rotation therein, means to clamp one edge of a master sheet to said drum,

means to press copy sheets against a master a drum rotatable therein, gripping means to on said plate, and means pivotally mounting said while the drum is stationary, and a second clampclamping means is opened.

11. A duplicating machine comprising a frame, a drum journalled for rotation therein, means to clamp one edge of a master sheet tosaid drum, means to press copy sheets against a master sheet on said 'drum, moistening means for supplying a solvent for the ink on saidmaster sheet, a control device for said clamping means whereby the clamping means may be opened and closed while the drum is stationary, a master sheet tray movably mounted in said frame and having its forward edge adjacent to said drum, spring means urging the forward edge of said tray toward the drum, a member on said tray for engaging the drum surface adjacent one end thereof whereby to prevent the forward edge of said tray from pressing against the master sheet on the drum, said drum having a depression adjacent the clamping means to receive said member and permit the forward edge-of the tray to drop down on the master sheet when said clamping means is positioned to receive a sheet from said tray.

12. A duplicating machine comprising a frame, a drum journalled for rotation therein, means to clamp one edge of a master sheet to said drum, means to press copy sheets against a master sheet on said drum, moistening means for supplying a solvent for the ink on said master sheet, a control device for said clamping means whereby the clamping means may be opened and closed while the drum is stationary, a master sheet tray movably mounted in said frame and having its forward edge adjacent to said drum, spring means urging the forward edge of said tray toward the drum, said forward edge having a part for pressing a master sheet against the drum, and means to prevent lowering of the said part onto a master sheet on the drum until the drum is stopped with said clamping means aligned with the master sheet tray.

' 13. A duplicating machine comprising a frame, a drum journalled for rotation therein, means to clamp one edge of a master sheet to said drum, means to press copy sheets against a master sheet on said drum, moistening means for supplying a solvent for the ink on said master sheet, a control device for said clamping means whereby the clamping means may be opened and closed while the drum is stationary, a master sheet tray movably mounted in said frame and having its for-' ward edge adjacent to said drum, spring means urging the forward edge of said tray toward the drum, said forward edge having a part for pressing a master sheet against the drum, and means to prevent lowering of the said part onto a master sheet on the drum until the drum is stopped with said clamping means aligned with the master sheet tray, said last named means comprising a projection on the tray adapted to ride upon the surface of said drum.

14. A duplicating machine comprising a frame,

a drum journalled for rotation therein, means to clamp one edge of a master sheet to said drum, means to press copy sheets against a master sheet on said drum, moistening means for supplying a solvent for the ink on said master sheet, a control device for said clamping means whereby the clamping means may be opened and closed while the drum is stationary, a master sheet tray movably mounted in said frame and having its forward edge adjacent to said drum, spring means urging the forward edge of said tray toward the, drum, said forward edge having a part for pressing a master sheet against the drum, and means to prevent lowering of the said part onto a master sheet on the drum until the drum is stopped with said clamping means aligned with the master sheet tray, said last named means comprising a cam member movably mounted on the frame, and means on said tray adapted to ride on said cam member.

15. A duplicating machine comprising a frame, a .drum journalled for rotation therein, means to clamp one edge of a master sheet to said drum,

means topress copy sheets against a master sheet on said drum, moistening means for supplying a solvent for the ink on said master sheet, a comtrol device for said clamping means whereby the clamping means may be opened and closed while the drum is stationary, and a second clamping means controlled by said device to hold the master sheet on the drum when said first named.

clamping means is opened, said second clamping means comprising a member mounted on said frame and spring'pressed toward said drum, and

means linked to said control device to hold said device for said clamping means whereby the clamping means may be opened and closed while the drum is stationary, and a second clamping means controlled by said device to hold the master sheet on the drum when said first named clamping means is opened, said second clamping means comprising a member mounted on said frame and spring pressed toward said drum, a cam bar movably mounted on the frame, and connected to said control device, said member hav-' ing a pin riding on said bar and holding the member away from-said drum in one position of the bar and releasing the member for movement toward the drum in a second position of said bar.

17. A duplicating machine comprising a frame, a drum rotatably journalled therein, gripping means to clamp a master sheet on said drum, means to press copy sheets against a master sheet on said drum, a hand lever on the frame, stop means actuated by movement of said hand lever to one position to stop said drum with the gripping means closed, and means to open said gripon said drum, a hand lever on the frame, stop means actuated by'movement of said hand lever to one position to stop said drum with the gripping means closed, and means to open said gripping means operable by movement of said lever toa second position, said frame having means,

thereon for holding a master sheet against the drum when said grippingmeans is opened after the drum is stopped. v

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