US3910184A

US3910184A - Quick coupling for the drum of a duplicating duplicator

Info

Publication number: US3910184A
Application number: US469095A
Authority: US
Inventors: Edward M Springer
Original assignee: Heyer Inc
Current assignee: Heyer Inc
Priority date: 1971-10-06
Filing date: 1974-05-13
Publication date: 1975-10-07
Anticipated expiration: 1992-10-07

Abstract

Duplicating machine having a drum rotatably mounted between a pair of side frames. Drum has a cylindrical wall having perforations communicating with an internal ink reservoir. An open mesh screen is stretched about the drum to provide an external cylindrical auxiliary reservoir immediately beneath an ink-distributing pad. Copy sheets are fed from a stack by adjustable pressure feed wheels and advanced along a path of movement to a first bight between a pair of forwarding rollers, and then to a second bight between an impression roll and the drum. Flexible paper strippers positively guide sheets to and from the drum, and are held out of wearing contact against stencil by raised peripheral rings at ends of drum. A pair of independently pivotal brackets support the ends of the impression roll and are spring-biased to press the impression roll toward the drum. Two transverse springs on each bracket are swingable to adjust the pressure of the impression roll on the drum. Impression roll is releasable without tools by manual endwise movement. A pivotal latch shaft has a pair of catch levers at opposite ends and radial paper sensing means intermediate them. The latch shaft is pivotable to and from a latching position wherein the brackets are engageable with the catch levers to hold the impression roll spaced from the drum and the paper sensing means across the path of movement between the first and second bights in the absence of a copy sheet. A cam, rotatable with the drum once per revolution, moves a rigid pivotal actuating frame and this in turn moves both brackets simultaneously to shift the impression roll away from the drum and to free the brackets and catch levers from frictional engagement with one another. Paper stop means is provided behind the forwarding rollers. Catch levers, controlled by the paper sensing means, hold the impression roll away from the drum in the absense of paper. Movements of parts and paper are synchronized enabling the cam to disengage the brackets from the catch levers as a sheet approaches the paper sensing means, and continued advance of the sheet against the paper sensing means swings the catch levers out of the way to enable the impression roll to press the sheet against a stencil on the drum. A single manually rotatable shaft connects and disconnects the drum. A quick release stencil clamp on the drum has a knife edge for removing the cover sheet from an underlying stencil. A manually releasable anchor enables quick, clean ink pad changes.

Description

'United States Patent [19] Springer [451 Oct. 7, 1975 [54] QUICK COUPLING FOR THE DRUM OF A DUPLICATING DUPLICATOR [75] Inventor: Edward M. Springer, Chicago, Ill.

[73] Assignee: Heyer Inc., Chicago, Ill.

[22] Filed: May 13, 1974 [21] Appl. No.: 469,095

Related US. Application Data [62] Division of Ser. No. 186956, Oct. 6, 1971, Pat. No.

[52] US. Cl 101/116; 101/141 [51] Int. Cl. B41L 13/06 [58] Field of Search 101/116, 118,132, 132.5,

101/141, 150, 153, 212, 216, 375, 127.1, 128.1; 118/DIG. 15; 301/124 R [56] References Cited UNITED STATES PATENTS 2,152,561 3/1939 Nigra 101/116 2,605,701 8/1952 Huebner... 101/216 3,205,814 9/1965 Huck 101/216 3,721,188 3/1973 Jacobsen et al..' 101/375 Primary Examiner.l. Reed Fisher Assistant Examiner-R. E. Suter Attorney, Agent, or Firm-McCaleb, Lucas & Brugman [57] ABSTRACT forwarding rollers, and then to a second bight between an impression roll and the drum. Flexible paper strippers positively guide sheets to and from the drum, and are held out of wearing contact against stencil by raised peripheral rings at ends of drum. A pair of independently pivotal brackets support the ends of the impression roll and are spring-biased to press the impression roll toward the drum. Two transverse springs on each bracket are swingable to adjust the pressure of the impression roll on the drum. Impression roll is releasable without tools by manual endwise movement. A pivotal latch shaft has a pair of catch levers at opposite ends and radial paper sensing means intermediate them. The latch shaft is pivotalble to and from a latching position wherein the brackets are engageable with the catch levers to hold the impression roll spaced from the drum and the paper sensing means across the path of movement between the first and second bights in the absence of a copy sheet. A cam, rotatable with the drum once per revolution, moves a rigid pivotal actuating frame and this in turn moves both brackets simultaneously to shift the impression roll away from the drum and to free the brackets and catch levers from frictional engagement with one another. Paper stop means is provided behind the forwarding rollers. Catch levers, controlled by the paper sensing means, hold the impression roll away from the drum in the absense of paper. Movements of parts and paper are synchronized enabling the cam to disengage the brackets from the catch levers as a sheet approaches the paper sensing means, and continued advance of the sheet against the paper sensing means swings the catch levers out of the way to enable the impression roll to press the sheet against a stencil on the drum. A single manually rotatable shaft connects and disconnects the drum. A quick release stencil clamp on the drum has a knife edge for removing the cover sheet from an underlying stencil. A manually releasable anchor enables quick, clean ink pad changes.

11 Claims, 30 Drawing Figures I92 214 25a 2 264 292 194 19a llll 3 i:1ll.'.3i?

US. Patent 0012. 7,1975 Sheet 1 of 13 3,910,184

llxlllliil'r Sheet 2 of 13 3,910,184

US. Patent O ct. 7,1975

U.S. Patent Oct. 7,1975 Sheet 3 0f 13 3,910,184

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US. Patent Oct. 7,1975 Shet4 of 13 3,910,184

Sheet 5 of 13 3,910,184

Oct. 7,1975

U.S. Patent US. Patent 00:. 7,1975 Sheet 8 of 13 3,910,184

Sheet 9 of 13 U8. Patent OCt. 7,1975

US. Patent Oct. 7,1975 Sheet 10 0f 13 3,910,184

Fig. 19

US. Patent Oct. 7,1975 Sheet 12 of 13 3,910,184

U.S. Patent Oct. 7,1975 Sheet 13 of 13 3,910,184

QUICK COUPLING FOR THE DRUM OF A DUPLICATING DUPLICATOR BACKGROUND OF THE INVENTION This application is a division of mycopending application Ser. No. 186,956, filed Oct. 6, 1971 now U.S. Pat. No. 3,835,772 for Compensating Impression Roller Mount For Stencil Duplicator.

The field of the invention is generally that of ink-type duplicating machines in which ink is transferred from the interior of a drum, through an ink pad and a stencil carried by the drum, onto copy sheets.

In such machines the copy sheets are fed, one at a time, from a stack, through a bight between the drum and an impression roll which presses the sheet against the stencil as it is drawn through the bight. The impression roll must not be pressed against the ink-covered stencil or it will smear the stencil and transfer ink to the backs of succeeding sheets. Mechanism must therefore be provided for preventing contact between the impression roll and the stencil when no sheet is fed to the drum. Providing such mechanism is complicated because the presence of a relatively fragile copysheet must be sensed to trigger the very substantial forces required for moving the impression roll to press the copy sheet against the stencil. A further complication is that modern duplicating machines must produce more than lOO copies per minute, so there is very little time for the impression roll to be moved after sensing the presence or absence of a sheet.

Machines of the type with which the present invention is concerned feed sheets in two separate movements with ,a definite stop or pause between them. There is an initial movement of the sheet from the stack, followed by a final movement across the drum. It is important that this initial movement be stopped at a definite point and at a definite time correlated with the rotation of the drum, to properly register the printing on the sheet. Prior machines have not precisely controlled such stopping and starting of the sheets resulting in a loss of precision in the printed copy.

A problem, sometimes called dotting develops in conventional duplicating machines at high speeds, resulting for all practical purposes in an upper speed limit which will not produce acceptable copy. Conventional duplicating machine drums have a cylindrical peripheral wall with perforations through which the ink flows to a pad, and thence to the stencil. At high speeds, ink flows more readily to the stencil portions over the perforations than to the portions between, giving an uneven or dotted pattern to the printing.

Stencils vary in their ability to transmit ink, so it is necessary to provide some mechanism for adjusting the pressure between the impression roll and drum during printing.

The duplicating machines are relatively complicated, having many parts which must be kept clean and in good operating order by regular maintenance procedures. For this purpose it is important that the drum be easily removable to provide access to parts beneath it.

Stencils commonly have a backing sheet which acts as a cushion during typing, and provides convenient means for handling as when assembling the stencil on a drum. After the stencil so assembled, the backing sheet is removed. Some stencils have a perforated line near the head portion along which the backing sheet may be torn off. Others, such as certain electronic stencils, do not have such a perforated line and the operator has to tear the backing sheet along a ruler or other separate straight edge tool held against the drum. This is not completely satisfactory because the operator must hold the tool by one hand, aligned by eye, and the resulting torn edge is often crooked.

SUMMARY OF THE INVENTION A principal object of the present invention is to provide an ink-type duplicating machine which functions with precision at high speeds and can be manufactured in volume at a reasonable cost.

A specific object is to provide mechanism controlled by a single manually operable knob or shaft for connecting the drum into and releasing it from the machine.

Other objects and advantages will be apparent from the following description taken in connection with the drawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a machine illustrating the present invention, the figure showing side ornamental plates or covers which enclose certain operative parts of the mechanism;

FIG. 2 is a partial plan view of the machine shown in FIG. 1;

FIG. 3 is a partial vertical section taken on line 3--3 of FIG. 2;

FIG. 4 is an enlargement of a portion of FIG. 3;

FIG. 4A is an external fragmentary view of the drum as seen in the direction of arrows 4A4A in FIG. 4;

FIG. 5 is a side elevation of the driving and timing mechanism viewed along line 5-5 of FIG. 2, but with the respective ornamental cover removed;

FIG. 6 is an enlargement of a portion of FIG. 5; FIG. 7 is a perspective view of the printing drum and some associated parts removed from the machine;

FIG. 8 is an enlarged fragmentary cross-sectional view of FIG. 7 taken along the line 8-8;

FIG. 9 is an enlarged fragmentary longitudinal crossectional view taken along line 9-9 of FIG. 2 showing mechanism operated by a single shaft and knob for I connecting and disconnecting the drum in the machine;

FIG. 10 is a sectional elevational view taken gener-' ally along line 10-10 of FIG. 2, with certain parts removed showing the relationship of certain components as a copy sheet is fed forward to begin the printing cycle;

FIGS. 1116 are schematic views similar to FIG. 10 but on a reduced scale showing subsequent operative positions of components as the copy sheet is advanced through the machine;

FIG. 17 is a perspective view of certain parts of the mechanism;

FIG. 18 is an enlarged fragmentary view of FIG. 17 along line 18-18;

FIG. 19 is a fragmentary view of FIG. 5 with the side frame removed to show one of the brackets which supports the impression roll and showing three adjusted positions of the spring biasing means;

FIG. 20 is an enlarged sectional view of FIG. 19 taken along line 20-20;

FIG. 21 is a view similar to FIG. 20 showing the impression roll partially disconnected;

FIG. 22 is a fragmentary view of FIG. 5 showing the mechanism for supporting and moving one of the forwarding rollers, with the bight between the rollers being shown in open condition; I

FIG. 23 is a fragmentary view similar to FIG. 22 but showing the bight between the rollers closed;

FIG. 24 is a plan view partly in section of the mechanism shown in FIGS. 22 and 23;

FIG. 25 is an enlarged view of a portion of FIG. 24;

FIG. 26 is a perspective view showing the drum connected to a removable carrying bailfor transfer to a storage stand;

FIG. 27 is a view of the bailand drum supported on a storage stand remote from the duplicating machine;

FIG. 28 is a fragmentary perspective view .of the drum supported on the storage stand; and

FIG. 29 is a fragmentary view of FIG. 28 showing the details of the shoulder and rib arrangement for supporting the drum.

DESCRIPTION OF THE PREFERRED EMBODIMENT The machine shown in the drawings comprises a housing 30 havinga pair of side plates or frames 32 and 34; a feed table or tray 36 for supporting a stack 63 of copy sheets 64 in position to be advanced into the housing; feed means 38 for advancing sheets from the stack; a pair of relatively

movable forwarding rollers

40 and 42 defining a first, variable bight 358 therebetween; a rotatable drum 44; an impression roll 46 movable relative to the drum and defining with the drum a second, variable bight 360 and guide means including lower and

upper guide plates

362 and 364 and strippers 375 for guiding copy sheets along a path of movement from the tray through the first and second bights. Paper stop means 54 and papersensing means 56 are disposed along the path of movement between the first and second bights.

Referring now in more detail to the above mentioned components and their cooperation in the machine, the

side plates

32 and 34 are held in fixed spaced relationship by a number of rigid cross members bolted or otherwise fastened therebetween. These include

transverse struts

58 and 60, rod 62, and other elements forming part of the housing.

The feed table 36 is shown and described in detail in Springer US. Pat. No. 3,417,988 issued Dec. 24, 1968 on Sheet Guiding Mechanism. Briefly, it supports a stack 63 of copy sheets 64 at the input end in position to be advanced one at a time into the housing. The operation is automatic, the rate of feed being one sheet per each rotational cycle of the drum. At the output end of the machine is a receiving tray 66 to collect the printed sheets.

Feed means 38 conprises a pair of rubberlike feed wheels 68 slidable to different spacings along a shaft 70 for sheets of different widths. The ends of the shaft 70 are rotatably journaled in a pair of arms 72 which are pivoted for up and down swinging movement outside the

respective side plates

32 and 34, about the aligned axes of two separate shafts 74. The arms 72 have upwardly offset sections 76 held by bolts 78 to the ends of a spacer rod 80. An arcuate slot 81 in each side plate provides clearance for the shaft 70 and rod 80 during up and down movements of the feed wheels 68.

As shown in FIG. 5, the end of shaft 70 adjacent the side plate 32 is connected through an overrunning clutch 82 to an outer race 86 having external gear teeth 88. An inner race 84 is fixed to shaft 70, and sprags (not shown) between the inner and outer races drive shaft counterclockwise when the outer race rotates counterclockwise as seen in FIG. 5. The sprags overrun or free wheel when the outer race rotates clockwise.

, The outer race 86 is rotatably driven by a train of gears 90 and 92 carried by the respective arm 72. Gear 90 is rotatable on shaft 94 which is mounted on arm 72 intermediate its ends. Gear 92 is rotatable on shaft 74.-

Both gears 90 and 92 are held in place by snap rings 96. Thus. it will be seen that the train of gears for driving feed wheels 68 swing vertically with pivotal movement of shaft 74, allowing the feed wheels to move down as the stack of sheets on the feed table is used up during operation of the machine.

The upper and

lower forwarding rollers

40 and 42 have a series of

rollers

98 and 102 on shafts and 104 respectively. I

The ends of shaft 100 are rotatably journaled in

side plates

32 and 34. Externally of side plate 32, as shown in FIG. 5, shaft 100 is connected to an inner race 106 of an overrunning clutch 108. The outer race 110 has external gear teeth meshed with both gear 92 and gear sector 112. Sprags (not shown) between the inner and outer races enable the shaft 100 to be rotated by the outer race only in a counterclockwise direction as seen in FIG. 5. Clutch 108 overruns when its outer race rotates clockwise.

At the other end of shaft 100, exteriorly of side plate 34, there is a friction brake generally designated 114 (FIGS. 17 and 18). This comprises a flexible friction strap 116 having a riveted loop 118 anchored to a stub shaft 120 on the exterior of side plate 34. Strap 116 has a bend 122 tensioned about a flat cylindrical groove 124 at the end of shaft 100 by a spring 126 held by pin 128 on side plate 34. This holds the shaft 100 braked against rotation unless the shaft is positively driven by a torque sufficient to override the friction of strap 116 against the brake groove 124.

As best shown in FIGS. 2225, the ends of lower forwarding roller shaft 104 are loosely rotatably journaled in bearings 128 carried by levers 130. The levers 130, together with the shaft 104, comprise a flexible actuated frame for supporting the annular roller elements 102. The loose journal connection represented by the clearance between each bearing 12 8 and shaft extension 129 (FIG. 25) comprises in effect a limitedly swivelable connection enabling the ends of the shaft 104 to move up and down independently of one another, within limits, thereby enabling the ends of the lower forwarding roller assembly 42 to press uniformly against the upper forwarding roller assembly 40.

Each lever 130 has an integral boss 131 at its midsection pivoted for rocking movement about a reduced end portion 133 of an actuating shaft 132. Each end portion of shaft 132 is rotatably journaled in a bushing 134 in one of the

side plates

32 and 34. The shaft 132 comprises part of a rigid actuating frame including actuating levers 136 which are held by screws 138 to T- handle 139 fast to the reduced diameter extension 133. A washer 141 is provided between

members

131 and 139.

Each lever 136 has an inwardly extending transverse pin engageable edgewise with the end portion of the corresponding lever 130 opposite the end portion carrying the shaft 104.

A tension spring 142 is connected between pin 140 and an anchor pin 44 on side plate 32. This biases the rigid actuating frame (shaft 132 and levers 136) coun terclockwise as viewed in FIGS. 22 and 23.

Two springs 146, both external of

side plates

32 and 34, are connected between an anchor opening 148 in each lever 130 and an anchor pin 150 on

side plate

32 or 34. Springs 146 exert a torque on the flexible actuating frame (shaft 104 and levers 130) urging the movable lower forwarding roller assembly 42 upward against the fixed upper forwarding roller assembly 40. Both the actuating and actuated frames referred to are thus biased counterclockwise (FIGS. 22 and 23) about the same shaft, namely shaft 132.

At the end of shaft 132 exteriorly of side plate 32 (FIG. 24) lever 136 has an opposite extension arm 152 with a follower roller 154 engageable with a cam for automatic operation to be described.

There is a lost motion relationship between

levers

130 and 136 on both sides of the housing. This effectively enables the lower forwarding roller assembly 42 to be moved downward as a unit, but allows the ends of roller assembly 42 to seek their own positions when moved upwardly for the best, uniform engagement with roller assembly 40. This lost motion arrangement is best shown in FIG. 23. There, shaft 132 and lever 136 are rotated counterclockwise sufficiently to disengage pin 140 from the lower edge 156 of actuated arm 130. This, of course, would be true on both sides of the ma chine. Because the shaft 104 and levers 130 comprise a limitedly flexible frame, each spring 146 moves each corresponding lever 130 in a direction to close the first bight 358, between the

rollers

40 and 42, on each side of the machine as shown in FIGS. 3 and 23. When the integral actuator arm 152 and lever 136 are rocked clockwise about the axis of shaft 132, both pins 140 will engage the under edges 156 of arms 130, rotating the latter clockwise (FIGS. 22 and 23) about shaft 132 and opening the bight between

rollers

40 and 42. This opened bight is shown in FIG. 22.

Returning now to the description of the synchronized drive mechanism for the feed wheels 68 and forwarding

rollers

40 and 42, the drum 44 is driven by a motor 158. As shown in FIGS. 7, 8 and 9, the drum, in turn, then drives the feed wheels and forwarding rollers.

The drum 44 comprises a pair of circular ends or heads 160 and a partially cylindrical peripheral wall 162 having apertures 164. An open mesh screen 166 covers the wall portion 162 and, as will be described, provides an auxiliary, cylindrical ink reservoir immediately beneath an ink pad 168 for instant access of ink thereto. Such auxiliary ink reservoir receives ink through the apertures 164 from a main ink reservoir 170 within the drum.

The apertured cylindrical wall section 162 shown in FIGS. 7 and 8 is the printing portion of the drum which supports the ink pad 168 and a stencil 547. Between the leading edge 172 and the trailing edge 174 (FIG. of the cylindrical printing segment 162, there is a recess 176 defined by an ink retaining wall 178 having a threaded cap 180 through which ink is put in the main reservoir 170. The recess 176 also contains ink pad clamp means 182 and stencil clamp means 184 both of which will be described in detail.

Each drum end or head 160 has a generally rectangular reinforcing plate 186 (FIGS. 7, 8 and 9) affixed thereto as by soldering or brazing. Plates 186 are parallel and each has an outer eccentric lug 188 and a pair of circumferentially spaced lugs 190 disposed closer to the rotational axis of the drum. As will be described, there is a lug 188 at each end of the drum. These provide convenient temporary anchor points for a carrying bail, to move the drum back and forth between the machine and a separate storage stand. The two pairs of lugs 190 at opposite ends of the drum 44 provide means for transmitting torque between the drum 44 and supporting

members

218 and 236, and they enable initial, positive alignment of the drum 44 and supporting

members

218 and 236 along their common rotational axis before they are connected together, and thereby make it possible to rapidly connect and disconnect the drum within the machine. To avoid inadvertent reversal of the drum within the machine, the opposite pairs of lugs 190 may be located at different radial distances from the center.

Referring to FIG. 9, an axial sleeve or tube 192 is soldered or brazed between the ends of the drum. Within the sleeve is an axially shiftable shaft 194 and an internally threaded bushing 196 which is fixed in position by soldering or brazing to the interior surface of sleeve or tube 192. The shaft has an inner extension 198 of sufficiently reduced diameter to clear the threaded bore of bushing 196. A guide washer 200 is supported on the extension 198 and is slidable within the bore of sleeve 192. A coil spring 202 is compressed between an internal snap ring 204 in a groove at one end of the sleeve 192, and an external snap ring 206 in a groove on shaft 194. The spring biases the shaft 194 to the right (FIG. 9), toward a position wholly contained between the ends of the sleeve 192. In this position the washer 200 engages the bushing 196 and serves as a stop for the shaft 194.

The mechanism for supporting the drum 44 between the

side plates

32 and 34 will now be described.

A supporting and driving tube 208 is rotatably journaled within a sleeve bearing, 210 in side wall 34. A drive pulley 212 is fastened to the supporting tube 208 in any suitable manner as for example by the set screw 214. A flanged hub 216 is fastened to the end of supporting tube 208 interiorly of the side plate 34, by solder or a press fit. A disc-like supporting member 218 is fastened to the hub 216. An alignment and driving member 220 is fastened as by rivets 222 to the inside surface of supporting member 218. As best shown in FIG. 7, the member 220 is T-shaped, having radially outwardly facing ledges or shoulders 226 for supporting the lugs to axially align the drum sleeve 192 with the supporting tube 208. Lugs 190 are spaced sufficiently to straddle the rib or stem portion 224 of the T-shaped member 220 and thereby provide an effective rotatable driving connection between the supporting disc member 218 and the drum.

A second supporting and driving tube 228 (comprising a substantial counterpart of supporting tube 208) is rotatably journaled within a sleeve bearing 230 fixed within side plate 32. A center shaft 232 is rotatable with supporting tube 228 and has an end bore 233 positioned to receive the outer end portion 264 of shaft 194 when extended as shown in FIG. 9.

A flanged hub 234 (similar to 216) is fastened to the inner end of center shaft 232 and is rotatable with that shaft and with supporting tube 228 in normal operation. A disc-like supporting member 236, which may be identical with member 218, is connected to the flanged hub 234 and rotatable therewith. A T-shaped locking member 220 and lugs 190, as described above for the other end of the drum, provide a releasable, rotatable driving connection between the supporting disc member 236 and the drum. A cam 238 is fastened to and rotatable with the sleeve 228. Cam 238 moves the impression roll 46 relative to the drum by mechanism which will be described.

By a worm and pinion means not forming part of the present invention, and therefore not shown, the

tube

228 and 232 are rotatably adjustable to vary the cam 238 relative to the drum. This raises or lowers the printing on the copy sheets in response to rotation of adjusting discs 239 on wheel 241 (FIG. 1).

Externally of the side plate 32 a drive bushing 240 is fastened to the supporting tube 228 by a set screw 242. Fastened to the drive bushing 240 and rotatable therewith is a drive gear 244 and

cams

246 and 248. As will be described, cam 246 moves the paper stop means 54, and cam 248 (fastened to 246 by spacer rivets 250) moves forwarding roller 42.

As shown in FIG. 3, the power source for the machine is the motor 158. This is connected through a suitable speed reducing power transmission (not shown) to drive pulley 212 shown in FIG. 9. Optionally, for a more simplified, less automatic version of the ma chine, one of the

tubes

208 and 228 may be turned by a hand operable crank not shown.

Thus, rotation of tube 208 by the drive pulley 212 (or the optional crank) rotates supporting drive disc member 218. This rotates the drum and the other supporting drive disc member 236 through the two sets of T- shaped locking members 220 and lugs 190. Dics 236 drives tube 228 and the parts rotatable therewith including drive gear 244 and

cams

246 and 248.

Having described the parts for supporting the drum, the means operated by a single handle for quickly con necting and disconnecting the drum between the sideframes will now be described.

Refer again to FIG. 9. A shaft 252 having a reduced diameter outer extension 254 is rotatable, and axially slidable, within supporting tube 208. A knob or handle 256 is held by a set screw 258. A snap ring 260 in an internal groove in tube 208 retains the shaft 252.

At its extreme inner end, shaft 252 has an externally threaded reduced diameter extension 262, adapted to be screwed into bushing 196 as shown in solid lines in FIG. 9.

To disconnect the drum, the knob 256 need only be rotated sufficiently to disconnect threaded extension 262 from threaded bushing 196. Then, by drawing the handle 256 outwardly from the tube 208 until the outer shoulder of shaft 252 engages the snap ring 260, the threaded inner end portion 262 will be moved to the broken line position shown in FIG. 9, disconnecting the right end of the drum at hub 216. As the shaft end 262 moves away from the extension 198 of shaft 194, the latter will shift automatically to the right (FIG. 9) until its outer end 264 is recessed within the end of the drum as shown in broken lines. This releases the left end of the drum at hub 234. Then, with the drum rotated so the locking members 220 are upward, the drum can be lifted straight upward, free of the machine.

Conversely, the drum 44 (or another drum with different colored ink) may be assembled quickly by lowering the drum into position for engagement of the lugs 190 with the locking members 220, followed by pressing the shaft 252 inward and turning handle 256 to engage locking means here comprising the screw threads in members 196 and 262.

When the shaft 194 is completely retracted by the spring 202 into the drum, the reduced diameter inner end 198 is positioned slightly to the right of the threaded bushing 196. This is shown in broken lines in FIG. 9. This permits initial inward movement of the shaft 252 to engage the end 198 of shaft 194 and shift the opposite end 264 into bore 233 in shaft 232 before the threads in members 262 and 196 are engaged. The assembly can then be moved to the solid line locked position shown in FIG. 9 by only one or two subsequent turns of the knob 256.

By the foregoing, the drive from motor 158 to the drive gear 244 has been described. The driving connections from gear 244 to the sector 112 will now be described to complete the driving train for the machine.

Drive gear 244 rotates crank gear 266 about pin 268 fastened to side plate 32. Crank pin 270 is connected by lever 272 to the midpoint of lever 274 which rocks back and forth about pin 276 fastened to side plate 32. Lever 274 is held to pin 276 by snap ring 278. At the free end of lever 274 a pin 280 is engaged with an arcuate slot 282 in sector 112. The sector is rockable about a pin 284 fastened to side plate 32 and a snap ring 286 holds it in place.

The sector has an arcuate line of gear teeth 288 meshed with gear teeth 290 on the outer race of overrunning clutch 108 which has previously been described.

Cyclic rotation of feed wheels 68 and forwarding rol ler 40 may now be summarized as follows. Rotation of crank gear 266 causes crank lever 272 to rock lever 274 back and forth. This alternately rocks gear sector teeth 288 clockwise, and counterclockwise, about shaft 284. Because of the overrunning

clutches

82 and 108, previously described, counterclockwise movement (FIG. 5) of sector 112 rotatably drives the feed wheels 68 in a counterclockwise direction to feed the top sheet 64 from the stack on the feed table 36; at this time, the clutch 108 is overrunning and therefore not driving the forwarding rollers. Next, when sector 112 rocks in a clockwise direction, overrunning clutch 108 drives the upper forwarding roller in a counterclockwise direction to further advance the sheet toward the drum. These separate advancing movements of the sheet by the feed wheels and forwarding rollers are synchronized with operation of the other parts of the mechanism as will be described.

As shown in FIGS. 17 and 19, the impression roll 46 is carried by a shaft 292 having its opposite ends respectively journaled in

brackets

294, 294 which are independently pivotable about stub shafts 296 extending inwardly from

side plates

32 and 34. The detailed construction of the mounting enabling the ends of the shaft 292 to be rotatably journaled in the brackets 294, yet sufficiently pivotal to enable the brackets to move up and down independently, is best shown in FIGS. 17, 19, 20 and 21 and will be described subsequently.

Each bracket 294 has an elongated body portion 320 and an out-turned flanged portion 322. The body portion has a pivot opening 324 engaging pivot shaft 296, and a catch pin 326 on the outer side of the bracket at the end remote from pivot shaft 296. Each bracket has interrupted elongated slot means consisting of a pair of horizontal, aligned

slots

328 and 330, the latter having three

detent notches

332, 334 and 336 in the upper edge.

An adjustment member 338 is manually movable lengthwise along each bracket to vary the pressure of the impression roll against the drum. Each adjustment member includes an elongated body portion 340 and an inturned grip portion 342 and each has a pair of

pins

344 and 346 engageable respectively within the

slots

328 and 330. The pins have enlarged heads 348 to keep them within the slots.

A tension spring 350 is connected between pin 344 and an anchor pin 352 on the

adjacent side plate

32 or 34. Similarly a tension spring 354 is connected between pin 346 and an anchor pin 356 on each side plate. As shown in FIGS. 17 and 19, the lines of action of

springs

350 and 354 extend substantially parallel to the vertical planes of movement of the brackets 294. Further, the lines of action of these springs are transverse to the lines of adjustment movement of the adjustment members 338.

In the embodiment disclosed, the adjustment members 338 are movable to three different torque positions to select three degrees of pressure of the impression roll against the drum. When pins 346 are in notches 336, the lines of action of the

springs

350 and 354 will be at a maximum distance from the pivot pin 296, and the combined upward pull of the springs to exert torque to the brackets and press the impression roll toward the drum will be at the maximum. When pins 346 are in middle notches 334, as shown in solid lines in FIG. 19, the lines of action of the springs will be somewhat closer to the pivot shaft 296, and the torque on the brackets and the upward pressure of the impression roll against the drum will be at an interme diate value. When pins 346 are in notches 332, the line of action of spring 354 will be on the opposite side of pivot shaft 296 (see FIG. 19) so that only springs 350 will exert any effective torque and upward pressure on the impression roll. Thus, each adjustment member 338 is movable between a maximum torque position where pin 346 is seated in notch 336, and a minimum torque position where pin 346 is seated in notch 332.

An important feature of the machine is the mechanism enabling the impression roll 46 to be connected quickly and easily into the machine, or to be disconneeted therefrom. This is best shown in FIGS. 17, 19, 20 and 21.

The impression roll comprises a resilient cylindrical cover 351 concentrically mounted on shaft 292. The ends of shaft 292 have reduced

diameter extensions

353 and 355. A snap ring retainer or stop 357 is provided in a groove at the end of each extension.

Sleeve bearing members

359 and 361, which may be identical, and each having an external flange 363, are slidably mounted on

extensions

353 and 355, respectively. A coil spring 365 on extension 353 is seated between a shoulder 367 and the flange of bearing member 359, biasing the latter in an outward direction. At the other end of shaft 292, a rotatable washer 369 is interposed .7 between shoulder 371 and the flange of bearing member 361.

In operating position, the impression roll 46 is assem bled with

bearings

359 and 361 seated within openings '373 in the brackets 294 as shown in FIG. 20.

drawing bearing 361 from opening 373, as shown in FIG. 21. So released, the impression roll may simply be pivoted about its remaining engaged end and swung out of the machine. The snap ring retainers 357 function as stops to limit outward movement or loss of the bearing members when the impression roll is removed from the machine.

As described, it is important that the brackets 294 be free to pivot independently, to the extent that opposite ends of the impression roll will be pressed uniformly against the drum. The ends of the shaft 292 must, of course, rotate within the

bearings

359 and 361 and the bearings must allow for limited pivotal movement of the ends of the shaft relative to the brackets. This is provided simply and practically in the present invention by making the clearances between the bearings and the shaft, and between the bearings and the brackets large enough to allow such combined rotational and pivotal movement.

As shown in FIG. 3, guide mechanism is provided for guiding copy sheets 64 successively along a path of movement from the stack 63 on the feed table 36 to the first bight 358 (between the forwarding rollers) and then to the second bight 360 (between the impression roll and the drum). This guide mechanism includes lower and upper supporting and guide

plates

362 and 364. The guide plates extend between the

side plates

32 and 34 and have transverse flanges fastened thereto by

bolts

366 and 368.

The lower supporting and guide plate 362 includes a vertical wall 370 with studs 372 for engaging the feed table 36, an upwardly inclined wall 374, and a lower horizontal wall 376 extending along and below the path of movement of the sheets. The upper supporting and guide plate 364 includes a downwardly inclined wall 378 and an upper horizontal wall 380 extending along and above the path of movement of the sheets.

Horizontal wall portions

376 and 380 have

openings

382 and 384 for the individual

follower roller elements

102 and 98 respectively.

The paper stop means generally designated 54 comprises a transversely extending plate having an up wardly inclined portion 386 terminating in vertical fingers 388 which extend through openings in the lower horizontal guide wall 376 when in their fully raised position (FIG. 10). The stop plate is fastened as by screws 390 to rock shaft 392 which is pivoted between the

side plates

32 and 34.

As best shown in FIG. 5, a paper stop actuating lever 394 is connected to rock shaft 392 externally of the side plate 32. The upper end of lever 394 has a follower roller 396 engageable with cam 246 already described in connection with FIG. 9. The lower end of lever 394 is connected by a spring 398 to an anchor pin 400 on side plate 32 and biases the lever 394 in a clockwise direction to keep follower 396 engaged with the cam 246.

Another important part of the invention is springtype paper stripper means functioning as an extension of the upper supporting and guide plate 364. This feature is best shown in FIGS. 2 and 3.

As shown in FIG. 2, the axial length of the drum 44 exceeds that of the impression roll 46. A pair of transversely spaced, flexible strips 375 of material such as spring steel are fastened by bolts 377 to the top of the inclined wall 378. The strips 375 extend in an outward direction over the end of the upper horizontal guide wall 380, tangent to the bottom of the drum as shown in FIG. 3, to anchor pins 379 on the side frames. Thus. the stripper strips 375 will positively guide a sheet to the drum and then positively strip it from the bottom of the drum it passes beyond the second bight by reason of the fact that the strips 375 extend continuously from the end of horizontal guide wall 380 to a position well beyond the second bight 360.

Each axial end portion of the drum has a peripheral ring 381 providing a slightly raised circumferential sur face engaging the strips 375 and keeping them out of wearing engagement with a stencil on the drum.

An important feature of the strips 375 is that because they are mounted on top of and substantially upstream of the edge of horizontal guide wall 380, they continuously engage the edges of a copy sheet to, through, and beyond the second guides This guiides the sheet to the drum, and positively strips it from the drum after printing.

Mechanism will now be described for moving the impression roll 46 toward and away from the drum and for holding the impression roll out of contact with the drum when the machine operates without paper passing through it.

A rigid actuating frame, generally U-shaped and designated 399 (FIG. 17) is interposed between the single cam 238, (previously described in connection with FIG. 9) and the two independently movable brackets 294. The rigid actuating frame consists of a countershaft 401 pivotally journaled in

side plates

32 and 34, and a pair of actuating arms 402 which extend toward the brackets 294. Each arm 402 has a lower roller 404 engageable with the top edge 406 of a corresponding bracket. One of the arms 402 has a follower roller 408 engageable with cam 238 previously described in connection with FIG. 9. A tension spring 410 (FIGS. 3 and 17) hold the rollers 404 engaged with bracket edges 406. This promotes quiet operation.

Because the actuating frame 399 is rigid, downward movement of either arm 402 is accompanied by identical movement of the other arm. Thus, in spite of the fact that both brackets 294 are independently movable to promote uniform upward pressure of the impression roll against the drum, both ends of the impression roll will be moved simultaneously downwardly from the drum when the high portion H of cam 238 engages follower roller 408. The part of the mechanism which holds the impression roll 46 out of contact with the drum in the absence of a copy sheet will now be described. A latch shaft 412 is pivotally journaled between the

side plates

32 and 34. A pair of identical catch levers 414 are mounted at the ends of the latch shaft. Paper sensing means 56 comprise radial fingers 416 carried by latch shaft 412 intermediate its ends.

The paper stop fingers 388 and the paper sensing fingers 416 are both along the path of movement of the copy sheets between the first and second bights as shown in FIG. 3.

The latch shaft 412 is pivotable between a latching position and an unlatching position. In the latching position shown in FIGS. 10 and 17, the catch levers are swung to a substantially vertical position with their notches 420 engaging bracket catch pins 326 to hold the brackets 294 in position to keep impression roll 46 out of contact with the drum. In the unlatching position, shown for example in FIGS. 14, and 16, the

catch levers 414 are swung free and enable the spring urged brackets to move the impression roll upward and press a copy sheet against a stencil on the drum.

Ornamental covers 422 and 424 (FIG. 1) are provided to cover the mechanism above described which is on the external surfaces of the

side plates

32 and 34. A hand wheel 241 is connected with supporting tube 228 (by means not shown) and adjusting wheel 239.

may be rotated in one direction of the other and (by means not shown) may rotate shaft 232 relative to supporting tube 228 to advance or retard the cam 238 relative to the supporting disc 236. This is no part of the present invention so will not be described in detail, but, briefly, this adjustment raises or lowers the location of printing on the copy sheet, as previously described.

An important part of the invention, facilitating the uniform distribution of ink over the copy sheet at high speeds is the open mesh screen 166 (FIG. 8) which is stretched permanently about the apertured, cylindrical peripheral wall portion 162 and comprises an integral part of the drum. This communicates via apertures 164 with the main interior ink reservoir 170 inside the drum. As the drum rotates ink is distributed over the inside of the wall 162 and passes through the apertures 164 into the interstices of the open mesh screen 166 which constitutes in effect a continuous cylindrical auxiliary reservoir externally of the wall 162.

The ink pad 168 will preferably have a flannel side fitted with the nap extending into the screen 166 and with an exterior fine weave surface of material such as nylon or silk. Thus, by capillary action of the nap fibers extending into the auxiliary reservoir, namely the screen 166, ink would be transferred rapidly and uniformly to the outer surface of the pad 168. This greatly inhibits dotting which occurs at high speeds with conventional drums having the ink pad directly on the apertured peripheral wall 162. This dotting effect results where ink cannot flow to the pad areas between apertures 164 as readily as it flows through the areas directly over the apertures.

The ink pad 168 may be assembled quickly and easily on the screen 166 utilizing the improvements of the present invention as follows.

Refer now to FIGS. 4 and 4A. The drum has an eye 430 fastened as by rivets 434 to each of the heads within the recess 176. Only one eye 430 is shown, this being on the head illustrated in FIG. 4 and at the top of FIG. 4A. These are near the leading end 172 of the cylindrical printing area 162. At the other end of the recess 176, adjacent the trailing end 174 of the cylindrical printing area 162 an angle member 436 is fastened, by a pair of bolts or rivets 428 attached to the floor plate 178. The base plate 440 of angle member 436 is supported above the floor plate 178 by washers 439 which are seated on the floor plate 178 and which encircle the bolts or rivets 438. A second angle member 442 is movable in the clearance between base plate 440 and floor plate 178. This movable second angle member 442 has a base plate 444 which is slidably retained in the above-mentioned clearance between

plates

440 and 178. Grooves 443 in the base plate 444 engage the washers 439 and guide the base plate for right and left movement as seen in FIG. 4A. A leaf spring 446 is riveted to the center of movable base plate 444 and has an upwardly inclined portion 448 extending through

central openings

452 and 453 in

upstanding webs

441 and 445, respectively. A small up-

Claims

1. In a duplicating machine, means for connecting and disconnecting a rotatable drum in a housing including: a pair of supporting members at the ends of said drum journaled in said housing for rotation with said drum about a common axis; first and second shafts aligned along said axis, and carried respectively by one of said supporting members and by said drum; said first shaft being manually movable between an extended position connected with said drum, and a retracted position disconnected from said drum; said second shaft being movable between an extended position connected with the other of said supporting members, and a retracted position disconnected from said other supporting member; means for moving said second shaft to its said extended position in response to movement of said first shaft to its said extended position, and biasing means, within said drum, effective to move said second shaft to its said retracted position in response to movement of said first shaft to its said retracted position; whereby movement of said first shaft in one direction connects said drum to both supporting members, and movement of said first shaft in the opposite direction disconnects said drum from both supporting members.

2. In a duplicating machine, the combination of claim 1 in which biasing means within said drum includes a spring urging said second shaft toward its said retracted position, and said shafts are engageable for overriding said spring while moving said second shaft to its said extended position.

3. In a duplicating machine, the combination of claim 2 including a lockable connection between said first shaft and said drum effective when locked to hold said shafts in their said extended positions.

4. In a duplicating machine, the combination of claim 1 in which: each of said rotatable supporting members has a pair of circumferentially spaced radially outwardly facing shoulders and a rib between said shoulders extending radially outwardly therefrom; and each end of said drum has a pair of lugs circumferentially and radially spaced thereon to straddle said rib and engage said shoulders on an adjacent supporting member when said drum and supporting members are in axial alignment, to facilitate aligning said drum with said supporting members before connecting said drum by said first and second shafts.

5. In a duplicating machine, the combination of claim 4 in which: a third lug is provided on each end of said drum radially outwardly of said pair of lugs; and said third lugs at the opposite ends of said drum provide connections for a bail to transfer said drum between said housing and a separate storage stand when said first and second shafts are in their said retracted positions.

6. In a duplicating machine, means for connecting and disconnecting a rotatable drum in a housing including: a pair of supporting members at the ends of said drum journaled in said housing for rotation with said drum about a common axis; first and second shafts aligned along said axis, and carried respectively by one of said supporting members and by said drum; said first shaft being manually movable between an extended position connected with said drum, and a retracted position disconnected from said drum; said second shaft being movable between an extended position connected with the other of said supporting members, and a retracted position disconnected from said other supporting member; means for moving said second shaft to its said extended position in response to movement of said first shaft to its said extended position, and biasing means within said drum effective to move said second shaft to its said retracted position in response to movement of said first shaft to its said retracted position whereby movement of said first shaft in one direction and in the opposite direction respectively connects said drum to and disconnects said drum from both supporting members; each of said supporting members having a pair of circumferentially spaced radially outwardly facing shoulders and a rib between said shoulders extending radially outwardly therefrom; each end of said drum having a pair of lugs circumferentially and radially spaced thereon to straddle said rib and engage said shoulders on an adjacent supporting member when said drum and supporting members are in axial alignment, to facilitate aligning said drum with said supporting members before connecting said drum by said first and second shafts; and a storage stand for supporting said drum separate from said housing having a pair of vertical support arms extending upwardly from a base each arm having a pair of stationary upwardly facing horizonal shoulders and a rib between said shoulders which are substantial counterparts of those on a corresponding one of said rotatable supporting members.

7. In a duplicating machine, means for quickly connecting and disconnecting a rotatable drum between a pair of side frames including: a pair of supporting members at the ends of said drum journaled in said side frames for rotation with said drum about a common axis of rotation; said supporting members having bores aligned along said axis of rotation; an axial sleeve in said drum; a screw-threaded bushing within said sleeve; a first shaft, within the bore of one of said supporting members, axially shiftable between an extended position engaged within an end of said sleeve, and a retracted position disengaged from said sleeve; a second shaft, within said sleeve, axially shiftable between an extended position having an end portion engaged within the bore in the other of said supporting members, and a retracted position disengaged from the bore in said other supporting member; and spring means within said drum urging said second shaft toward its said retracted position; said first shaft having a manually operable handle at its outer end portion exteriorly of said one supporting member, and a screw-threaded extension at its inner end portion; said first shaft, when moved to its said extended position, being engageable with said second shaft to shift said second shaft to its said extended position, and being rotatable to engage the threads of said extension and bushing to hold said shafts in their respective extended positions, thereby simultaneously connecting both ends of said drum with said supporting members; said first shaft, when moved to its said retracted position, being disengageable from said second shaft enabling said spring means to shift said second shaft to its said retracted position, thereby simultaneously disconnecting both ends of said drum from said sUpporting members.

8. In a duplicating machine, means for quickly connecting and disconnecting a rotatable drum within a housing including: a pair of supporting members at the ends of said drum journaled in said housing for rotation with said drum about a common axis of rotation; said drum having axial openings at opposite ends thereof; a first shaft, having an external handle, journaled in one of said supporting members for axial movement through one of said axial openings to and from a position engaged with said drum; a second shaft, journaled within said drum for axial movement through the opposite of said axial openings to and from a position engaged with said other supporting member; means for moving said second shaft through said opposite axial opening in response to movement of said first shaft through said one axial opening, to thereby connect both ends of said drum simultaneously with said supporting members by means of said shafts; and biasing means within said drum for moving said second shaft automatically to a position wholly recessed within said drum in response to withdrawal of said first shaft from said one axial opening, to thereby disconnect both ends of said drum simultaneously from said supporting members.

9. In a duplicating machine having a printing drum rotatably supported between a pair of spaced side frames, apparatus for connecting and disconnecting said drum comprising: axially aligned supporting members rotatably journaled in said side frames; an open sleeve extending between ends of said drum along the rotational axis thereof; a first, manually actuated shaft supported by one of said supporting members for axial movement therein; a second, automatically actuated shaft supported by said sleeve for axial movement therein; the other of said supporting members having connecting means engageable with said second shaft when extended from said sleeve; said second shaft being movable through one end of said sleeve to engage said connecting means in response to movement of said first shaft into the other end of said sleeve to thereby connect both ends of said drum to said supporting members; locking means for locking said shafts in connected position in response to rotation of said first shaft relative to said sleeve; a stop within said sleeve; and spring biasing means automatically urging said second shaft toward said stop to a position wholly between the ends of said sleeve in response to withdrawal of said first shaft from said sleeve; whereby both ends of said drum can be connected or disconnected simultaneously in a single operation by manually moving said first shaft into or out of said sleeve at one end of the drum.

10. In a duplicating machine, the combination of claim 9 in which: each of said supporting members includes a mounting disc, said discs being parallel, coaxial and spaced apart to enable fitting of said drum endwise therebetween; and a rotatable driving connection is provided between each said disc and an adjacent end of said drum including a radial rib and a pair of circumferentially spaced eccentric lugs, enabling said drum to be assembled between said discs, and to be disassembled therefrom, by moving said drum transverse to the axis of rotation of the drum to respectively seat, and unseat, each rib between a corresponding pair of said lugs; whereby said drum is centered relative to the discs by said first and second shafts, and whereby rotational torque is transmitted from one disc to the other through the drum via the rotatable driving connections.

11. In a duplicating machine, the combination of claim 9 in which: said sleeve and said first shaft have a screw-threaded connection therebetween; and said shafts are engageable before said screw-threaded connection is engageable on inward movement of said first shaft; whereby in connecting said drum between said sideframes said second shafT may be extended from said drum in two successive increments, namely, a straight axial movement of said first shaft prior to engagement of said screw-threaded connection to thereby preliminarily extend said second shaft from said sleeve, followed by rotation of said first shaft to finally extend and lock said second shaft in extended position.