US2588878A - Screen printing apparatus - Google Patents

Description

March 1l, 1952 w. M. REEMELIN ETAL SCREEN PRINTING APPARATUS 5 Sheets-Sheet l Filed Sept. 16, 1946 AT TO R NEY5 5 Sheets-Sheet 2 W. M. REEMELIN ET AL SCREEN PRINTING APPARATUS Wl l www fw; ATTORNEYS March 11, 1952 Filed sept. 16, 194e March 11, 1952 wl M, REEMELlN ET A L 2,588,878

SCREEN PRINTING APPARATUS Filed sept. 1s, 1946 SASheetS-Sheet 3 L #79.175,I f

/r\\ //l\ INVENTORI WALLACE M. REEMELIN BY ROGER W. OLMSTED AT TOR NEY March l1, 1952 w.Y MREEMELIN ETAL SCREEN PRINTING APPARATUS Filed sept. 16, 194e 5-Sheets-Sheet 4 www INVENTORS. WALLACE M. REEMELIN ATTORNEYS March 11, 1952 w. M. REEMELIN ETAL SCREEN PRINTING 'APPARATUS "5 'sheets-sheet 5 Filed' sept. 16,- 194e )37am M W7 ATTORNNS Pafentecl Mar. 11, 1952 SCREEN PRINTING APPARATUS Wallace M. Reemelin, Berkeley, and Roger W. Olmsted, San Francisco, Calif., assgnors to Foster and Kleiser Company, San Francisco,

Calif.

Application September 1.6, 1946, Serial No. 697,294

2 Claims.

This invention relates to screen printing apparatus of the type used for printing by the silk screen process, and has for one of its objects the provision of apparatus for eieeting a more rapid printing than heretofore, particularly where relatively large sheets are printed, such as each of,`

the'sheets used on large bill boards to make up u the large poster.

lAnother object of the invention is the provision of screen printing apparatus that facilitates the positioning and removal of the sheets that.l

have been imprinted as well as the printing, and with the minimum amount of labor:

A still further object of the invention is the provision of screen printing apparatus that is arranged and adapted to enable one workman,

to position and remove the relatively long sheets from the elongated rectangular printing base of the apparatus from one of the longitudinally extending sides of such base while a single workman at one of the ends of the apparatus actuates the squeegee in one direction or the other in direction longitudinally of the base and printing frame, the latter generally corresponding in shape with the printing base.

In screen printing apparatus, the screen' cr `printing frame and printing base therebelow are usually oblong in plan view and are positioned horizontally. The frame, heretofore, has generally been hinged along one of its longitudinally extending edges to the base, andtherefore the paper or material to be printed must be positioned and removed from some one or more of the three remaining sides when the printing frame is swung open. Inserting or removing the paper from the one longitudinally extending side that,

is opposite the printing frame hinges is awkward" where long sheets of paper are being printed inasmuch as two operators must insert theelongated sheets, one being at either end of the latter, and the operator that positions the sheets must work from the same side of the apparatus to adjust the sheets so they will register correctly with the screen or previously printed color. If the sheets are inserted and removed from opposite ends of the frame, it is obvious that the time for removal is longer than were the sheets removed from one side, and also much greater space is required.

Also, heretofore it has beentcustomary in larger screen printing apparatus to require two operators to operate the squeegee, the latter being L drawn from end to end of the screen frame. One operator is at each side of the frame. The squeegee is removed from the `frame aftereach printing to enable the frame to swing open,

With the present invention, one man at one side of the apparatus positions and removes the paper, and the paper is removed from the side of the frame opposite the operator. Also, only one man at one end of the apparatus is required to operate the squeegee and the squeegee remains in position on the printing frame after each operation. In addition to these advantages, the printing frame and printing base are moved relative to each other to and from closed position by means of fluid pressure, which merely requires the opening and closing of a valve, whereas in prior apparatus, the operators have been required to manually swing the frame away from the printingwbase. When it is considered that the printing frame must be of rugged construction and on large apparatus is about four feet wide and twelve feet long for printing 34 by 84 inch sheets,

'it is manifest that the manual swinging of the frame takes time and effort even though each such frame is usually counterbalanced.

Other objects and advantages will appear in the description and in the drawings.

In the drawings:

Fig. l is a side elevational view showing the apparatus with the printing frame and printing base together and the squeegee about midway between the ends of the printing frame.. A portion of the frame is broken away adjacent one end to show structure otherwise concealed.

Fig. 2 is a plan view of the printing base only, with the supporting posts and braces indicated in dash lines.

- Fig. 3 is a side elevational view of the base of Fig. 2, one of the telescoping posts being broken vaway and indicated in section.

Fig. fl is an enlarged fragmentary sectional view takenalong the line 4-4 of Fig. 2.

Fig. 5 is aschematic View of the fluid pressure `system connected iwith the extensible telescopic j supports for the printing base.

.. v1i'ig."6 is an enlarged part elevational and part sectional view of one of several identical elevating ,means for automatically elevating the squeegee in .Section- Fig. 9 is an enlarged sectional View taken along line 9-9 of Fig. 8.

Fig. 10 is an enlarged sectional view along line Ill-Iii of Fig. 8. i Fig. 1l is an enlarged, part sectional and part elevational view through one of the collapsibie pneumatically actuated supports for the base frame.

Fig. 12 is an enlarged, fragmentary sectional view of part of the squeegee and printing frame.

Fig. i3 is an enlarged View as seen from line I3-I3 of Fig. 12.

Fig. 14 is a diagrammatic, simplied plan view of the printing apparatus and a portion of the conveyor belt.

In detail, a rigid, horizontal printing frame I is supported on legs 2 elevated a substantial distance above the floor 3. This frame is usually oblong in plan View, and in the present invention a platform 4 is at one end of the frame and at about the same elevel. Stairs or a ladder 5 may be provided for the squeegee operator' I5 toY climb to and descend from the platform. Usually the platform has an extension 1 along oneV side of the f frame for said operator to walk from one end of the frame Vto the other, and a railing 8 may also be provided for safety reasons.

In Fig. 14 a diagrammatic plan view' of the arrangementY is shown, and in said View it will he seen that thestack or supply 9` of paperv to be printed is at the end of the printing frame op,-

pcsite platform 4, while a take-ofiv roller IU? is along one longitudinally extendingl edge off the" A conveyor I'I extends away from. the

frame. tafe-oii' roller for carrying the printed sheets through or under a drier that Vdoes not form a part of this invention and that is not shown. The operator that positions the sheet to be printed and that removes it after the printing operation, stands at about position I2. It is to be understood that the take-ofi' roller I0 and conveyor II are all at about the level' of the printing frame, as will later be described more in detail.`

The printing base, or what would, in conventional' screen printing constitute the stationary table, is indicated at I3, and is below the printing frame.

ThisY base i3 is supported at its four corners on telescopically extensible and collapsible tubular legs, generally designated I4, whichl legs are extended by pneumatic pressure to different levels as will later be explained. In Fig. l the full line position of the printing lbase indicates its uppermost position, while the dash line position Iii` indicates the intermediate working; position being somewhere around 35 or 40 inches from theV floor. There is a third or lowermost position (Fig. 3) in Y which the legs are fully collapsed to their limit,

and in which the. printing base is about half way' between position, I5 and the floor` When in this latter position there is adequate space between the printing base and the printing frame to facilitate work by an operator on the lower side of the screen or stencil attached thereto, or any" other work that requires, more Working space than is permitted by the space between position I5 in Fig. 1 and the full line position of the printing frame.

The legs I4 each comprises an outer cylinderA Secured to the upper end of said cylinder said head being centrally apertured for reciprocation ofy intermediate cylinder therethrough, the latter having a piston or cup-washer 21 secured to its lower end and reciprocable in outer cylinder 2t. The head 25` mayl function as a stop for the plunger' 21.

The head 25 is also formed with a passageway 28 connecting with air pressure line 29 at one end and communicating with the inner lower end portion of intermediate cylinder 2 I when the latter is iin extended position, thus enabling air pressure entering; said portion to extend the inner cylinder Inner cylinder 22 is provided with a head at its' uppery end on which. the printing base I3 is supported,A while the lower end is provided with a piston or cup-washer 30 that is reciprocable in intermediate cylinder 2|. The said cylinder 22 is also reciprocable through a head 3| that is in the upper end of the intermediate cylinder 2 I.

As seen in Fig. 5', air lines 24' communicate between the iower ends of each of the outer cylinders` 20 and a common air line 35 that in turn connects with a source 36 of air under pressure. A manualor foot operated valve 31 in said air line 35 connects the outer cylinders with said source 36 when in the position indicated in Fig. 5 or when the valve is' rotated a quarter turn the outer cylinders may exhaust to the atmosphere for collapsing under the weight of' theprinting base to the position shown in Fig. 3.

Air lines 29 `communicate with the space betweentllel pistons 21', 3D and a common air line 38 that in turn.v connects with said source 35. A foot or' manually actuatable valve 33 in line 31 is similar tovalve 31 and when in the position indicated in Fig. 5v admits air under pressure to below piston 30 for maintaining they cylinder 22 expanded as seen in Fig. Il. A quarter turn of thevalve 39. will open the interior of cylinder 2| to" the atmosphere permitting the inner cylinder 22r to descend to collapsed position within the intermediate cylinder 2l.

In actual practice, when the apparatus is ready for printing, the valve 31 is open, thus elevating the printing base to position I5 (Fig. 1) and the valve remains open'. The operator then positions a sheet-of paper in proper position on the printing base and opens the valve 39, whereupon the base is elevated, bringing the sheet against the screen' or stencil carried by the latter. The squeegee is then moved across the screen to force the paint. through the latter and onto the sheet that' is on the printing base, after which the valve 39 is moved a quarter turn so as to close the line leading to the source of air 36, and open to exhaust the lines 29 leading from the valve tothe lower ends of the intermediate cylinders,

.whereupon the printing frame carrying the printed sheet will be lowered to position I5 (Fig. 1)'. vThe operator then merely lifts the sheet 4i! (Fig. 7a) onto the rapidly rotating take-01T roller III that in turn deposits the printed sheet on conveyor I-I for carrying below infra-red drying lamps 4 I. The conveyor II and roller Iii may be driven by any suitable source of power connected with a belt or chain 42 that in turn extends over a pulley VI3 supporting one end of conveyor Il, while a suitable belt 44 may connect the pulley shaft 45 with roller Ill'.

The printing base I3' has upstanding members 46 projecting from its upper side along two adjacent edges of the base for positioning each 5h98@ t0 he Printed, in @he .Same position on said base in or to insure proper register. These members must be retractable or movable downwardly when the base is moved against the printing screen to permit the printing step. Fig.- 4 shows the yieldable support for each member 46.

Each member (which is preferably rectangular in horizontal cross-sectional contour (Fig. 2) extends through a correspondingly shaped opening in said base. A shoulder 41 (Fig. 4) on each member limits the upward movement thereof, and expansion springs 48 connect the lower ends of said members (below the upper surface of base I3) with said base. Thus, as soon as the upwardly projecting ends of the members 46 engage the printing frame, the springs 48 will expand to permit said ends to come flush with the lower side of the frame whereby the sheet on said base will be tight against the printing screen or stencil therebelow. 'Ihe springs will cause the members 46 to automatically return to the' position shown in Fig. 4 when the printing base is lowered.

In order to prevent objectionable shock, expanded coil springs 49 are carried by the printing frame and depend therefrom (Fig. 1). These springs are engaged by brackets 50 (Fig. 4) carried by base I3 just before the printing base reaches the uppermost end of its movement, thus cushioning the blow that would otherwise result from engagement between the printing frame and base when the latter is moved to printing position. An upward projection `I on each bracket 50 (Fig. 4) is adapted to enter the lower end of each spring 49 when said base frame is in elevated printing position. Other similar springs 52 carried by the intermediate cylinders 2| function for the same purpose.

The printing frame, generally designated I, comprises marginal frame members 54 (Figs. 8, lo) that may be angle iron strips arrangedwith one of their sides 55 vertical and their other sides 56 horizontal and extending outwardly relative to the center of the frame. These strips are arranged to provide an oblong or rectangular frame (Fig. 7).

The screen 58 is secured at its marginal portion against the underside of the sides 56 of angle strips 5e by strips 59 that in lturn are secured to the inwardly extending` sides 6I) (Fig. of an outer frame formed of angle strips 6I. The other sides 62 of angle strips 6I extend vertically across the outer sides of angle Strips 54 and project above the level of the upper edges of the sides 55 of the latter. `An outer frame 63 en closes strips 6I and carries the later.

0 The lower sides 60 of angle strips 6I terminate below the lower sides 56 of angle strips 54 along lines spaced outwardly of the inner sides of the latter strips, thus permitting the printing lbase to pass into the space defined by the free inner edges of lower sides 66 of strips 64 and into close engagement with screen 58.

The lower sides 56 of angle strips-54 may be apertured at spaced points for passing elements 55 on strips 59 therethrough. These elements are each formed with a horizontal through opening for a wedge 66 (Fig. 12) that functions to tighten strip 59 against screen 58. Upon knocking out the wedges the screen is readily removed for replacement.

The upper edges of angle strips 6I (Figs. 8, 10) that extend along the longitudinally extending sides of the screen frame, form tracks for flanged wheels 'I6 of the squeegee.

The squeegee itself is generallyl designated 69A y and comprises a cross member 'II that extends between wheels 'IIJ and over screen 58. This cross member carries the flexible blade 'I2 (Fig. 9) that engages the screen 58 and that functions to scrape the painting medium over the screen from end to end of the latter during each printing operation. The blade or scraper portion of 4the squeegee is vertically adjustable toward and away from the screen by means of a screw 'I3 -that threadedly extends through a nut 'I4 secured to a transversely extending metal strap 'I5 that is centrally between the ends of said cross member, 1I. The lower end of screw 'I3 is rotatably secured to a vertically sliding blade holder T6 (Fig. 9) that receives the upper edge of the ilexible blade '12. A spring 'I8 reacts between the holder 'I6 and a washer 'I9 against nut 14 to yieldably hold the holderl6 in expanded position, while a predetermined pressure on the squeege will cause the latter to move upwardly compressing the spring 18. By turning the screw 'I3 the blade holder may be moved in one direction or the other axially of said crew until the desired position for best work is obtained.

A relatively long handle 'I9 is secured to the squeegee and projects slantingly upwardly therefrom in the direction of the platform 4. and over the latter so that the operator 6 on said platform can move the squeegee from one end of the printing screen to the other upon walking back and forth on the platform.

The handle 79 is generally of U-shape with the free ends connected to the ends of the squeegee as best indicated in Fig. 8, while the closed end of the U is adapted to be grasped by the hands of the operator as seen in Fig. 1.

At the same points where the free ends of the U-shaDed handle i9 connect with the squeegee are laterally projecting arms 8i (Fig. l2) that extend laterally from the squeegee in the same direction as arrn '19. Each of these arms carries a roller 82 at its outer end, and each such roller is adapted to -engagethe upper edge of the side of the angle strips 54 that extend parallel with the angle strips supporting the squeegee (Fig. 13). A brace 63 extends upwardly from the outer end of each arm 3 to the side members of arm 'i9 to brace the wheels 532.

The provision of said wheels enables the operator to elevate the squeegee, if he so desires, by pivoting the squeegee on the wheels upon moving the handle 'i9 downwardly.

At the opposite ends of the screen frame are portions 85, 86 that are outwardly bey-ond the printing portion of the screen. The painting medium on the screen is deposited on one or the other of these end portions according to the position of the squeegee. These portions may be imperforate or may be blocked off by extensions at the ends of the printingr base or in any other suitable manner. The important thing is that the paint is held on said portions against going through the screen. or frame when the printing base is moved away from the screen frame or vice versa. Such portions are employed in practically all conventional screen printing apparatus.

The present invention provides means for automatically elevating the sdueegee over the paint after the latter has been drawn across the screen in one direction and for then causing the sdueegee to re-engage the paint upon reversing the directional movement of the squeegee for drawing the paint back across the screen.

The above means comprises a pair of oppo-sedly positioned vertical plates @il (Figs. 1, (i, 7) posispaced, vertical, parallel links M.

tioned adjacent the vertical sides 6-2 of the angle strips 6I: on which wheels lil of the squeeg'ee are supported. There one pair at each of the corresponding ends of the angle strips 6|-, and each of said plates extends through the upper flange 9| (Fig. 6)' of the side frame members E3'. The plates 90' are horizontally elongated, and the end of each plate nearest a central point intermediate the ends and frame members 63 is connected to said frame' members' by a pair of horizontally Said links 9A are pivotally connected at their upper ends to said end. of each plate 98 by pivots 95, while the lower ends' of said links are' connected with frame members 63` by pivots 95. A spring 9)? yieldably holds each plate 90 in elevated position against one end 98 of the slot in flange 9| said end being most remote from said links, or adjacent the outer ends of the frame members 63. The upper edge of each plate is parallel with and above the level upper edge of the side 62 of each angle strip di on which the wheels 'it' are supported. The adjacent ends of the pair of plates at opposite ends of each of said angie strips extend slantngly upwardly as at 93 to said upper edge' of each plate, and. the tracks' formed by said sides 62 of said angle strips' extend slantingly upwardly at points 99 adjacent the outer ends of said plates so that the wheels l' of the Squeegee in moving from thev screen over' said portions t5 or 36 at the :s:

ends of the screen, will move upwardly onto the upper edges |05) of plates 9d' and then onto the elevated ends lill of sides Thus the blade of the squeegee. will pass upwardly over the supply of pair'it` it has drawn over the screen' as soon as the paint is deposited on either of said positions 85, or 86.

The plates Si! are' held against the ends 9% oi the slots in ilanges 9! against downward movement when the wheels 10 run upwardly onto said y plates over inclined edges 93. However, upon movement of the squeegee, as soon as the wheels 'l0 run downwardly over the edges 93 of sides 62 onto the ends of plates 9e that are remote from links 94, the plates 9!! will swing downwardly to position the' squeegee blade alongside the paint that is on either portion 85, or 86 as the case may be, for drawing said paint across the screen 58 upon continuing the movement in said reverse movement. The operator may, of course, tilt the squeegee carriage at any time about rollers 82 for elevating and lowering the squeegee blade,

'and the sdueeg'ee can be rolled on said rollers in said tilted position as well.

In operation in printing a conventional job on sheets that are, say 34 X 84 inches in size, the operator at position I2 (Fig. 14) may position the printing base in the dash line position I5 shown in Fig.k 1. The stencil is placed on the printing base, being properly positioned by the projections 46 that are along the sides adjacent the feed device 9 and the take-oil roller ID. The operator then actuates valve 39 for elevating the printing base to a position against the underside of the screen 5B. The operator 6 then draws the paint over the upper side of the screen by means of the squeegee 69, thereby causing the stencil to stick to the frame. A sheet of any kind may be between the printing base and the stencil to keep the base clean during the operation of adhering the stencil to the screen.

In some 'instances parts of the stencil may have to be adhered by hand, or removed, after the. rst operation above described, and in such instances the operator l2 may lower the printing base to fully depressed position (Fig. 3)'v and do the necessary workV on the stencil. Once the stencil is ready for doing the necessary job the printing base isagain elevated` to position l5 (Fig. 1) by actuation ofv valve 3T, and. a sheet is dra-wn Vfrom the feed stack at 9 onto said base and positioned? bythe projections 46'. The valve 39' isthen actuated andi the' printing' base quickly carries the sheet to the screen, whereupon the operator E movesV the squeegee' across the screen, effecting a printing on the sheet on the printing base. The printingv base is then lowered to position I`51 and operator i2 quickly lifts4 it onto take-off' roller I that quickly deposits the same on conveyor llt that in turn carries the sheet to below the drying' lamps 4t..

Another sheet isf placed on the printing base and the'- operation is repeated.

The operator 6 quickly manipulates the squeegee by himself. andthe operator' I2l handles the feeding and removal' of they sheets by himself. There is no swinging of a heavy printing frame and. s'qiie'egee, nor' is more than one man necessary for feeding' and'` removing sheets from the machine.

It is to be'. understood that the invention as described in' detail is' merely illustrative of the preferred' form of theinvention and` is not necessarily restrictive thereof'.

We claim:

1. Screen printingV apparatus comprising a horizontal printing' frame? supporting a screen through which the printing medium is to be forced from above, a fiat, substantially rectangular horizontal printing base; below said frame for supporting' the material to' receive the' said medium for making the desired imprint, axially extensible vertically disposed telescopic posts supporting saidba'se at' points adjacent' its four corners-1 for vertical reciprocabl'e movement to and from said frame, means for admitting uid undery pressure into said posts for extending the same" for causing said movement to saidframe and for exhaustingsaid iiuid for permitting collapse of said posts and movement of said base away from said frame, foot controlled' valve means below said frame for controlling the flow of said iiuid intol and out ofsaid posts, and power means along one edge of said base for carrying sai'd material away from said base when said p'osts are' collapsed and saidy base is spaced below said frame, the laterally projected area of the spacebe'tween said base and said frame along the edge of said base opposite said one edge thereof being unobstructed for manual manipulation of said material on said base by an operator positioned adjacent said one edge when said posts are collapsed. V

2. In screen printing apparatus that includes a rectangular, horizontal printing frame carrying a stencil screen, tracks along two opposite sides of said frame, a squeegee having wheels rotatable on said tracks for supporting said squeegee for movement over' the screen longitudinallyV of said tracks, horizontal end members respectively eX- tending between the corresponding ends of said twoI opposite sides and adjacent the ends of said tracks for supporting the painting medium to be drawn by said squeegee across said frame when said squeegee is moved from one end of said tracks to the other, a pair ofcorrespondingly shaped elements respectively positioned adjacent corresponding endsl oi said tracks and projecting above the latter for engaging the wheels ofv the -squeegee and elevating the latter upon said wheels going over said elements said elements being adjacent said end members whereby said squeegee will be elevated to pass over said medium after the latter is drawn onto said end members, means yieldably supporting said elements in elevated position, stop means for holding said elements elevated against downward movement for so elevating said squeegee when the latter is moved 01T said screen in direction away from the latter and onto said elements, said elements being movable downwardly away from said stop means and against the yieldable resistance of said means under the weight of said squeegee upon reverse movement of said squeegee in direction toward said screen whereby said squeegee will engage said medium on said reverse movement for drawing the same over said screen.

WALLACE M. REEMELIN. ROGER W. OLMSTED.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,556,998 Katcher Oct. 13, 1925 1,843,116 Aldcroftt Feb. 2, 1932 1,922,341 Aldcroftt A1115;w 15, 1933 1,922,710 Owens Aug. 15, 1933 2,014,373 Brickell Sept. 17, 1935 2,039,909 Kem et al. May 5, 1936 2,061,679 Simonton Nov. 24, 1936 2,321,134 Fleisher et al. June 8, 1943

Images