US1832828A - Screen printing machine - Google Patents

Description

Nqv. 17, 1931. E. BORREGARD 1,832,828`

SCREEN PRINTING MACHINE l M B.Y Ml I l N E. BORREGARD 1,832,828

SCREEN PRINTING. MACHINE Novf 17,' 19:'{17v 'F1-led July 13. 1927 4 snts-sneez 2 mvENToR,

- NOV- 17, 1931- E. BQRREGARDy SCREEN PRINTING' MACH'lNE Filed July 13, 1927 4 Sheets-Sheet 3 mm mm Inail. lvnnllnlnllla.

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INVENTOR,

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E. B'ORREGARD SCREEN PRINTING MACHINE Filed July 13. 1927'A 4 :Sheets-Sheet A 4 INVENTOR/ Patented Nov. 17,1931' *y UNITED STATES PA-TENT" OFI-ica ERNST B ORBEGARD, OF GREAT NECK, N EW YORK, ASSIGNOB` T0 LEO, H. FULLmGINO., OF LONG ISLAND GITY, NEW YORK, A CORPORATION OF NEW 'YORK SCREEN PRINTING rMACHINE appiication mea July 1a, 1927. serial ivo'.- 208,429.

meable by a coating of shellac', or 'similar may 10 terial.

The machine includes asprincipal featurs, means for feeding, registering-and securing the successive sheets .position for lprintraising and lowering the stencil whiclnis usually called a scre'en; means for maintaining a suitable amount of color upon the screen` and, A for automatically wiping the color over the upper face of the screen to produce a proper color imprint. through the screen upon the card, and means for prop- `erly disc operation. 'v The `machine also includes other novel or limproved combinations or arrangements of arts as suiiciently explained-in the following detail description of the accompanying' drawings,wh ich show one representative embodiment of the invention. After considering this example, 'skilled persons .will understand that many variations may be made, and I contemplate the-employment of any structures that are properly within the scope of the appendedv claims.

Fig. lis a side elevation of aeomplete machine embodying my invention.

Fig. 2 is a plan view.

Fig. 3 is a section at 3-3,Fig. on an en'-l larged scale,

.crative positi@Jun-and.-.-'.3v A o Fig. 7 is a section, enlarged,'at 7-7, Fig. 2.

` The screen proper consists of a sheet of silk of suitable dimensions the marginsof. 50 which are secured to the edges of a frame so -The frames heretofore employed ing or stencilling; means for supporting,

arging the card after the stencilling Fig. 4 is a section at Fig. 1,onan eri- Fig. 6 shows the same parts iii-another (ip-,

that the screen fabric overlies one main face of the frame and the inner lcontour of the frame forms a reservoir for the li uid color. ve been simple rectangular frames of'wood or other suitable material (not illustrated); the frame illustrated embodies improvements set forth in my co-pendingv a pli'ca'tion, Serial No. 272,917 filed April 281. 1928, now U. S. Patent .#1742,889, dated January 7th, 1980.

g Tlie silk screen is first coated all over with ermeates the screen a .watersize l.which fabric. After this dries the desi is placed upon the inner face of the size screen by applying shellac coating thereto the areas corresponding. to the design being left free andI all other areas being filled in with. the shellac coating, After the shellac dries the water sizing on the design spaces or areas is washed out, leaving the natural fabric in permeable condition, and producing in eect a screen-stencil for .application to the cardboard or other base. (Desirabl strips of adhesive paper are then placed a out the inner contour of the frame, with portions overlapping the -margins of the screen, to prevent t e liquid colora from leaking out between the and this paper stripping may then be shellacked.

. The cardboard sheet9 is then placed on a table, the screen is superposed upon it with screen and under faces of the frame members, I

suitable simple precautions for proper registration, and a substantial quantity of the liquid color, which is practically a paint, is poured upon the screen, being confined by the inner edges of the frame. A simple handupper face'of the screen from one end to the other of the ,frame'thus insuring aJ-properpermeation of the stencil design by the color,

'ope-rated wiper is then brushed across'the f or practically wiping the color -through the'. stencil spaces and applying it properlyto the card. -v The frame is then lifted.' .the card reipgved, another card positioned on the table, the screen replaced and so on. In'a multicolorprocess, to which the methodis espe-v cially well adapted, the successive cards are placed in racks for drying and a number of vstencils are prepared on similar screens, each from the front ends of the side members.

corresponding to one color of the complete design, and the cards are successively operated upon with the successive stencils, to produce various highly-decorative poster or other designs.

While the described hand process produces multi-color pictures or designs of high quality, it is relatively slow and expensive on account of the time required for placing and removing the sheets, and manipulating the stencil and wiper, and my invention therefore provides a substantially automatic machine, for carrying out by machine operations the described printing or stencilling process.

The machine is built upon or about a main frame see Figs. l to 5, which includes legs 20, rectangular side members 21 with suitable cross connection, and brackets 22 extending .1' feed table 23 is supported by the brackets 22 and a printing table 24 is located at the top of the main frame.

Card-feed conveyors in the form of chains 25 run from one end of the machine to the other, the upper stretches of the chains being located in slots 25a in the tables, so that their upper faces are flush with the upper table surfaces. At one end each chain passes around a sprocket 26 on a shaft 27 rotatably mounted in bearing-blocks 28, which are adjustably mounted in brackets 22 by means of slots 29 therein and bolts 30 to hold' the bearing-blocks in adjusted position. At their other ends the chains pass about sprock- 'ets 31 on 'a shaft 32 mounted in fixed bearings 33.

Each chain carries spaced pushing and gripping devices 34, these devices on the respective chains being aligned in the lateral directions of the machine. As shown in Figs. 5 and 6. each of-the devices includes a block .35 which may be one of the chain blocks, provided with a shoulder 36 to engage the card edge. r1`he next adjacent chain block 37 is formed or provided With an arm 38 having near its end a tooth or prong 39 adapted to engage or perforate the card. As the devices 34 pass about the sprocket 26 the relative angular deflection of the blocks 35 and 37 causes the arms and prongs 39 to be in elevated position and when blocks 35 come to a position almost vertically above the sprocket axis, shoulders 36 engage the card edge and begin to advance the card over the table, and immediately thereafter the chains straighten out` blocks 37 coming into line with blocks 35 and the free ends of' arms 38 are thus moved downward, pressing the points of prongs 39 upon the card. The prongs do not at this time however necessarily puncture the card, but complete puneturing thereof to cause positive engagement of the card with the feed devices is provided at a point in the further travel of the card, as later explained.

At the front end of the machine (at the right, Figs. l and 2) curved guards 45 are providedy to protect the operatorI from the card feeding devices as they rise above the level of the table in the last part of their travel around the 'sprockets 26. The guards are provided Wi-th openings at 46 to permit thfet card feed devices to pass onward to the le The operator places the cards C to be iniprinted successively on the feed table 23, the lateral position of the card being determined by an adjustable gauge 47. The feed devices 34 on the two .chains then approach simultaneously and just as they emerge from the openings of the guards they engage anu feed the card in the manner above explained.

In each feed movement of the chains the card is carried from the initial position on the feed table to a proper position on the printing table to receive a stencil impression. ln this travel the surface of the card is brushed to clean and properly condition it by a cylindrical brush 50 carried by shaft 51V mounted in bearings 52 which are vertically adjustable in brackets 53 located near the rear end of the feed table., The brush isl constantly rotated by pulleys and a belt 50a from a main shaft 136 (later referred to), revolving in the direction indicated by the arrow, so that dust, lint etc. are brushed back away from the printing table. Thebrush is desirably enclosed in a cover or housing 54. Just rearward of the brush, rolls 55 are mounted above the conveyor chains in brackets 56 secured to the brush-housing frame, see Fig. 3. As the card feed devices 34- pass under rolls 55 the rolls press down the upper members 38 of the feed devices and force the studs or teeth 39 through the card so that the card is then firmly locked in the feed devices. The chains are then simultaneously brought to rest with the card positioned upon the printing table, and accurately registered both in longitudinal and lateral directions by the positive connection of the card to the feed devices and also by positive locking and registering means for the conveyor chains, as later described. After the steneilling .or printing operation the chains'are again advanced and the stencilled card is ejected on to any convenient receiving device such as a carryoif belt or the table 58,v Fig. 1. As the feed devices 34 reach 'a position directly above shaft 32 and begin to travel around the sprockets 31, the angular deflection of the chain links supporting said device causes the upper members or jaws to open to release the card, and the speed. of the chains is such that the card is thrown well onto the table 58 and clear of the chains. At the same time that a card is ejected another one is fed from the feed. table-'to the printing table.

To support and move the screen frame see Figs. 2,'3 and 4 in proper relation to the card feed movements, -a rectangular screen-supportingv frame 60 corresponding to the plan outline of theistencilirame, is connected to on a longitudinal shaft 63.. T e screw studs 5a of the printin frame are pasted up through correspon ing `a ertures 1n frame brackets Gil/which have bearings 62 mounted 60, and nuts 64 are app ied tosecure thescreen frame in position.` The'side members 65 of frame 60, and angle strlps. 66 havmg vertical flanges 67, form in eiect upward extensions of the inner contour of thescreen frame and provide a reservoir to hold any desired`a1nount of liquid'color, with walls deep enough to avoid splashing of the color. The screen frame is raised, by slight oscillationof frame 60 about shaft 63, during movement of each card to printing position, and

after the card has been positioned the printing frame is lowered to bring the screen close to but not in actual Contact with the upper face of the card. Means fonautomatically moving the frame 60 is described hereafter.

'Automatically' actuated scraping or color distributing means is'provided to properly force or brush the color through the permeable portions ofthe screen representing the pattern, and thiso means is also devised to force the screen downward the slight distance required to make Contact with the upper face of thecard as the rubbing or scraping blade passes over the upper face of the screen, 1m-

i' mersed in the colorthereon. For this pur-l pose carriage guides are secured above frame'60 at either side thereof. Ascrapercarriage 772 extending across the machine is vmounted to reciprocate in straight. guide channels 73 in the inner faces of the members 70. `A driving chain 7 4 has its ends connected to forward and rear portions ofthe carriage as at 75. These connections maybe inthe formV of'brackets 76 to which the chains are connect/edand which in turn are connected to a vertical plate 77 of the carriage by means of slots 78 therein'and studs or screws 79 on the brackets passing through the slots, A spring tensioned between the brackets "may serve to take up slack in chain ,74. T he inwardstretch ofo the chain, in line with the brackets 76, passes around idler pulleys 8() mounted on vertical stud shafts 81. Lateral stretches of the chainpass about a'pulley 82 and a'sprocket 83 carried by short shafts 84 and molfnted 'for .rotationin brackets 86 to complete the chain circuit, which includes the outer longitudinal stretch 87. Sprocket 583' is the driver for chain 74:, and for this pui'- posais-connected to a bevel gear 88 which i' so engages. another bevel gear 89 revolnbly mounted on shaft 63. Gear 89 is .driven by' connections alater described, Aand since it is mounted on the pivot'axis of frame 60 the chain 74 may'be drivenlto and ro-for the reciprocation of the scraper carriage without any interferencev with the driving' connecnuts 907e engaging the screws.

tions being caused by the tilting. movement lof the frame.A v

A transverse shaft 90 is mounted for oscily lation in the end members of the scra r carriage. A scraper body 90a is detacha l conv`nected to' short sleeves 90b which are ree to rotate upon shaft 90. The sleeves 90b have lugs 90o projecting at opposite sides of the shaft. Other sleeves 90d are rigidly se ured on the shaft and these sleeves have opp itelyprojecting lugs90c', and set screws 90f pass ing the scraper block and Scrapers, as for erz-l ample when anew screen is placed in the machine for use with another color. The scraper stri s 91 desirably consist of substantially st i but'ilexible material such as rubber composition or canvaswith rubber vulcanized thereon, "and they arev detachabl secured to angular vfaces ofthe block 90a y plates 92 i and thumb nuts 93.

vTwo scraper blades are provided because itis desirable to scrapethe color across thescreen with a dragging rather than a vertical or pushing action; that is, the active.scraper blade should be inclined rearwardly downward as shown in Fig. 3, in which the carriageis moving to the right and the' activel (lower) scraper 91 is in contact with the screen and is therefore inclined in the manner'just stated, which gives a smoother and more positive oo n- 'tact with the screen and more eiective wiping action of the` color upon and through t screen design, than`ifthe blade were held vertical or inclined in a direction opposite to .that shown. This also provides for maintaining the proper distribution of the color in the reservolr provided kby the screen frame and' the supporting frame 60. Thus if a single scraperwere used it would tend to push ahead ofv ita great partof the color in the reservoirand upon return movement the color would remain behind the blade instead 'of being in front of it .o r more uniformily distributed over thescreen. By the present arrangement however whenl the lower blade of Fig. 3 reaches the end of its'travel near the right hand `end of the frame, it is raised and the other scraper lowered Vand at the same time the color which was previously trapped aheadof the first named blade isor'eleased and is vthen in position to be pushed ahead of theI blade which is about` to make' a'return movement (to the left as viewed in Fig. 3) For the purpose of'properly oscillating shaft 90 to make one of the wiper blades operative for each direction of carriage travel, an arm 100 is secured to shaft 90 near each end thereof, and these arms are provided with outwardlyprojecting cam rolls 101 to cooperate with guide-channel and cam devices provided on the inner faces of the guide structures 70. Thus on the inner face of each guide structure is an upper channel 102 and a lower channel 103 separated by a central flange or rail ,104. At the forward end this rail is bevelled or tapered to form a descending cam face 105 and at its rear end is bevelled to form an ascending cam face 106. At the forward end of the lower channel 103 is a rising or upwardly directed cam member 107 leading to a horizontal rail member or flange 108 elevated slightly above the level of the lower point of cam 105. At the rear end of theupper channel 102 is a descending or downwardly inclined cam member 109. ln the position/shown in Fig. 3 in which the scraper carriage has started to move forward, the cam rolls 101 on arms 100 are located in the lower channels 103, thus positioning the rock shaft l90 as shown, to hold the rearward scraper blade 91 in contact with the screen to properly wipe the color over and through the screen for the production of a proper imprint upon the card as the carriage moves forward. ,Before the carriage reaches its foremost position rolls 101 ride up' on the cam faces 107 and in the final travel of'the carriage are located on the horizontal flanges 108.` The shaft 90 is thus oscil'lated to partly raise the rearward scraper Jand lower the for- .0f scraper-pressure.

ward scraper 91 and thus relieve the screen Shaft 90 has a fairly tight fitin its bearings and moreover there -is no force tending to accidentallytilt the faces 107 and 105, and then ride up on the cam faces 105 and enter the upper channels 102, and the forward scraper blade 91 is thereupon positioned for proper a'ction in the rearward movement of the carriage. As the carriage approaches its rearward position the rolls 101 strike the downwardly inclined cam faces 109 to partly raise the forward scraper blade and partly lower the rear scraper blade, and then in the forward movement of the carriage the rolls encounter the downwardly inclined cam faces 10G which further tilt the scrapers to the position shown in Fig. 3, where the rear scraper is in action during the forward travel of the carriage.

The carriage driving mechanism is so arinranged that after a card is positioned on the i while the screen is raised, the printed card ejected and a fresh one positionedon the printing table; the screen is then lowered and the scraper moves in the other direction to properly apply the color, and so on.

esirably shock absorbing means is provided to yieldably check the carriage at either end of its stroke, consisting of plungers 110 mounted in guides 111 at either end of the carriage with springs 112 compressed between the heads of the plungers. Lugs 113 are provided at opposite ends of the frame in position to be engaged by the plunger-s whereupon the springs are compressed and the carriage is yieldingly checked.

While not necessary in ,all cases, it is desirable to provide additional means for properly and positively holding the cards in printing position, and prevent the screen from raising the card as the former rises. Suction means is desirably employed for this purpose and comprises apertures or channels 113 located in any desired positions in the upper face of the printing table to eX- haust air from under the lower face of the card and thus hold it flat and smooth upon the table by atmospheric pressure acting upon the upper face of the card. The various apertures or channels 113 are connected by ducts formed on or in the table and these are connected to pipes114, and all the pipes are connected to one conduit 115 leading to an exhaust pump 116.

As a simple means of releasing the card from the vacuum pull or suction ei'l'ect after the printing operation, a cylindrical fitting 117 is interposed in the air conduit 115, the

vupper end of this fitting being formed as an annular valve seat 118 to Vcooperate with a valve 119. This valve is connected to a rocker 120 pivoted on a liXed frame member, one arm of the rocker being connected to a spring 121 which urges the valve to open position. The rocker arm to which the valve is connected has a toe 122 to cooperate with a latch member 123 pivoted at 124 to the tilting frame,`and urged to the left as viewed in Fig. 1 by a spring 125. The latch has a notch 126 terminating in upper and lower horizontal faces 127 and 128, to cooperate with the toe 122, and a lower bevelled face 129. Whenever the screen-supporting frame is moved downward, just after a card is positioned on the printing table, the bevelled face 129 of latch 123 slides over the end of the toe 122, and thereafter the latch springs back to vertical position and its upper shoulder 127 depresses the toe 122 andf'closes the valve 119, thus -closing the suction pipe line, and air is therefore exhausted from the under face of the card tohold it in proper flat condition for printing. After printing, in the upward movement of the screen supporting frame,

-the lower shoulder 128vof latch 123 engages toe 122 and opens the valve, thus destroying the suctlon in the air conduit and freeing the -45 jecting from the frame. The link card, which is then moved away by the conve or chains. V

he drivin means or connections may vary greatly, ut in the preferred example shown they comprise the following:

A motor 130 located in any convenient position near the machine has its shaft 131 connected byv avv belt 132 to exhauster 116, which ma be continuously driven, when the suction e ect is controlled by Such means as above described. The motor sha-ft is also connected by suitable reduction gearing 133, sprockets and a chain 134 to a sleeve 135 revolubly mounted on a transverse shaft 136 which is the main driving shaft of the machine proper. The sleevel is releasably con-vv nected to shaft 136 by a. clutch 137 having a suitable shifter 138, anda shifting linkage 139, connected' to a lever 140, convenient to the operator. On one end of the drive shaft is ahand wheel '141 for turning the machine over by hand in making adjustments, etc.

Near the other end of shaft 136 is a sprocket 141 connected by a chain 142 to a sprocket 143 on a shaft 144. The chain is adjusted by an idler 145. On one end of shaft 144 is a cam body 146 having in one face a cam groove 147 in which islocated -a`cam roll 148 carried b the lower endvof a plunger 149 mounted or reciprocation in guides 150.

rlhe cani plunger maybe arranged to positively elevate the screen frame, butin a' referred arrangement as shown the frame 1s actually moved upward by spring plungers 151, Fig. 1, mounted in cylinders 152 se- A cured to one of the framexside members 21,

these plungers, being urged upward by springs 153 within the cylinders.` The upper ends of the spring plungers 4engage lugs 154 connected to the screen-supporting frame. The upper end of the cam-actuated plunger 149 'is connected to the screen supporting frame by a swinging link 155, adapted to enter a slot 156 formed ina lug 157. pro- 158 which engages in half-roundV notches 159 in the upper face ofthe lug at. either side' of the. slot; When the link is in active i position as shown, after a card has been positioned on the table for printing, the c am slot in cam body 146 acts. on roller 148 and the plunger to pull the latter down, and s o pull downthe screen frame to active position;

and afterl the scraper carriage has been traversed over the screen to apply the color the manner above described thecampermits the' plunger andframel to rise under the impulse of the spring plungersr 151,

co whereafter the printed card is carried away Aand a new one positioned, and so on.

" In order to permit' the screen frame to be raisedhigher than'it normally rises in the operation of the machine, for example in t6 order to remove the screen and replace it slot.

l For driving the'card conveyor chainsin .properly timed relation to other partsv of the mechanism, shaft 144 is provided with'a gear 160 engaging a gear 161 onanother transverse shaft 162. `This shaft is arranged to drive the conveyor chain driving shaft 32 by any suitable means such as a Geneva mechanismv and multiplying gearing, for

the purpose of securing the proper conveyor chain travel alternating with rests for the performance of other operations particularly the movement of the screen frame and the traverse of the scraper carriage. Specifically, in the vpresent example shaft 162 has lthereon the usual Geneva stud or driving roll 163'ca`rried by an arm 164, and a stopdisk to cooperate with a four-part Geneva Y Wheel 165 on another transverse shaft `166. This Geneva wheel is arranged to rotate freely on its'shaft and is held in-an axially' .fixed position although the shaft is mounted for axial movement lfor a purpose later referred to. Connected to revolve with the Geneva wheel is a large gear 167, engaging a pinion 168 on conveyor chain drive shaft' 32. The gear ratio is such that in each` quarter turn of the Geneva wheel, produced by one revolution of each of shafts 144 and 162, the conveyor drive shaft 32 is rotated a lsuiiicient number of turnsV to advance the -conveyor chains a proper distance for one card-feeding operation.

Since the parts leading up to the conveyor drive shaft, and -the conveyor system proper including the chains andV sprockets, have considerable inertia, it is desirable to provide means for checking their advance at the end of the feed movement. For this purpose a brake drum 170 is secured on conveyor drive shaft 32, cooperating with brake' shoes 171 urged to braking position by a spring 173, and retracted by a'zcam 174 connected to a lever 17 5, which is provided with va cam roll' 176 running on the periphery of a cam 177- fixed on ,shaft 162.A The notch 178 in cam 177 is dimensioned and positioned so that at 'the end of the proper feed travel of the conveyor chains, roll 1 76 drops into thecam notch ordepression and the brake isapplied by its spring 173 to bringv the .conveyor system to rest with the Idesired promptness, and shortly. thereafter, and before the next propulsion -of, the conveyor chains, the caml roll is moved tothe circular .periphery of the cam,. and the brake is released, ready foi the next conveyor action.

For the reciprocation of the scraper carlos las'

riage, shaft 162 has near the end opposite to the Geneva mechanism, a segment gear 180 cooperating with a pinion 181 having a stopsector 182 to cooper-ate with the smooth semicircular periphery of gear 180. The face of pinion 181 is broad enough to remain insoperative contact with gear 180 at all times although the pinion is shifted axially in the shifting movement of shaft 166 referred to shortly below. Also operatively fixed on shaft 166 are bevel gears 183 and 184, spaced aproper distance foralternate 'engagement with a bevel pinion 185 on a horizontal shaft 186 which is also provided with a sprocket 187 connected by a chain 188 to a sprocket 189 secured to the hub of bevel gear 89 mentioned earlier above, which gear is revolubly mounted on the longitudinal shaft 63 and has a driving connection also above explained to the carriage driving chain 74. Near the `center of shaft 166 cams 200 are secured in spaced relation at either side of cam fingers 201 carried by a fixed yoke 202. The driving mechanismincluding gear. 120, pinion 181, and bevel gears 183 and 184, are so proportioned that at each revolution of shaft 162, corresponding to one feed movement of the conveyor chains, the scraper carriage drive chain is driven in one direction or the other to provide for the full travel ofthe carriage in the Acorresponding direction while the toothed part of gear 180 rotates pinion 181, and then.

the pinion and the driving mechanism leading from it to the scraper carriage is held stationary during the next half rotation of gear 180, while its semi-circular peripheral portion is engaged with the stop sector of pinion 181. Cams 200 are so proportioned and arranged that near the end of a rotative movement of pinion 181 and its shaft, or at the beginning of the next rotary movement, the shaft is shifted longitudinally, first one way and then the other, to bring gears 183 and 184 alternately in engagement with opposite sides of bevel pinion 185. .Thus the scraper carriage driving system from pinion 181 to the scraper carriage is alternately driven in opposite directions to provide the-desired full travel of the scraper carriage in one directionand then after the positioning of a fresh ,card and of the screen frame in relation thereto, for traverse of the scraper carriage in the other direction, and so on.

It is desirable in some cases to provide additional means for insuring accurate registration of the card feed mechanism by the accurate positioning of the chains to which the card is positively secured in the manner above described. This is especially desirable because these machines are usually employed in a multi-color process where the same card has to be successively positioned in the same or different similar machines, the number of these positionings corresponding to the number of colors in the design, and very accurate registration at each operation is therefore essential. For this purpose a stop disk 210 is notch 211 is provided in the periphery ofthe disk. A plunger 212 is provided to cooperate with the notch, this plunger having a tapered end and being reciprocably mounted in a socket 213 secured to the frame. The lower end of the plunger is connected to a bell crank fulcrumed on shaft' 166, and one arm of the bellcrank is provided with a cam roll 215 cooperating with acam 216 on shaft 162. The cam is dimensioned and positioned on its shaft so that just as the conveyor drive shaft 32 is being brought to rest by cessation of the driving impulse, and the application of its brake 171, at the end of a card feed action, the rise of cam 216 operates the bell crank 214 and forces the tapered end of plunger 212 into the stop socket, and the cooperating tapered formation of the socket and plunger therefore roduces an extremely accurate angular positioning of the stop disk, the drive shaft and the conveyor chains, thus accurately positioning or registering the card for printing, regardless of any play or backlash in the gearing leading to the'conveyor drive shaft 32.

Byfthe described arran ement ofthe screen supporting frame and ot er parts carried by it, and especially the pivotal connection of this frame to shaft 63 located at one side of the machine, when latch 155 is disconnected in the manner above described, the supporting frame may be swung to completely 0upright position and will then be located vertically at one side of the machine, 4leaving the printing table entirely free and clear so that it can be easily and conveniently cleaned. In ordinary operation the total vertical movement (or swinging movement of the frange about its axis 63) is only about 2, this slight motion being made possible by the employment of automatic card feeding means; and the total speed of the machine, or the total output, is correspondingly increased. Y

I claim:

1. In a screen printing machine comprising a feed table, a printing table aligned therewith, means for feeding successive cards from the feed table to the printing table and away from the printing table, a screen-supporting frame movably mounted above the printing table, and means, for moving the frame vertically, the combination therewith of a wiper carriage mounted for reciprocation above the screen, two iexible wipers thereon located in dierent oblique vertical planes, means for reciprocating the wiper carriage, cam means carried by said wiper carriage and a guide extending along said printing table co-acting with said cam means for moving said wiper carriage to therebyA Dfi ICO

move said Wipers alternately to and from active position whereby one wiper is in wiping contact with the screen surface while the carriage moves in one direction the other wiper is in active position while the carriage moves in the othervdirection.

(2. A screen printing machine comprising a printing table, a feed table, a printing table aligned therewith, means for feeding successive cards from the feed table to the printing table and away from the printing table, a screen-supporting frame movably mounted abovel the printing table, means for moving the frame vertically, and means for cleaning the successive cards during their movement toward the printing table.

3. In a screen printing machine, a printing table, a screen supporting frame pivotally mounted at one side of the table, means yieldably supporting the other side of the frame, means for moving the frame vertically, said means comprising a cam and a vertical plunger, and means carried by said plunger for quickly releasing the connection between said plunger and the frame. v

4. In a screen printing machine, a printing table, a screen supportlng frame pivotally mounted at one side ofthe table, a Wiper'carriage reciprocating in guides on the frame, a.

drive chain for the carriage supported to move in a substantially horizontal rectilinear path, means for driving the chain alternately in opposite directions, and a ielding connection between the chain and t e carnage.

5. In a screen printing machine, a printing table, a screen supporting frame, a Wiper car-vv .riage, a Wiper shaft mounted for oscillation in the carriage, means for oscillating the shaft, wipers mounted on the shaft, Vand means for adjusting their in relation to the shaft.

6. In` a screen printing machine, a printat a side of said printing table transverse screen' supporting frame vrelative to said printing table, and means independent. of

means.

7. In a screen printing machine, a-printing table, a screen supporting frame, a wiper carriage, wiper means rotatably supported a certain direction cards to said screen supspecification this angular position' ,to said certain direction for supporting said i by said wiper carriage, means forfeeding in Y screen supporting frame and said wiper carriage relative to said printing table, and means independent of said card feeding means for holding the fed card in position on said printing table during the period of operation of said wiper means.

8. A screen printing machine comprising a printing table, a screen-supporting frame above the table, means for moving the frame vertically in relation to the table, a feed table, means for feeding successive cards from the feed table to the printing table and away from the printing table, a brake for checking the movement of said card feeding means, and means for applying vthe brake substantially at the end of each conveyor movement.

9. In a screen printing machine having a printing table, a screen supporting frame, means foroperating the frame, a card conveyor for 'advancing cards successively to printing position on the table, and move- `ment limiting means for the conveyor comprising a member revolving in accordance operating with a notch in said member, and means for retracting the plunger. f

In testimony whereof I have signed this 1st da-y of July, 1927. ERNST BORREGARD.

las;

porting frame in -pre-determinedpositon I over said printing table, means, secured'at a side of said printing table transverse to said a"-oertain direction for' jointly supporting Said

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