US2646749A - Stencil printing apparatus - Google Patents

Description

u y 28, 1953 I J. B. THOMAS ET AL 2,646,749

} STENCIL PRINTING APPARATUS Original Filed Feb. 5, 194'? 2 Sheets-Sheet l INVENTORS 0 JOHN BTHOMA$ COURTNEY E. MOOQH OUSE AiTOIQNEY y 8, 1953 J. B. THOMAS ET AL STENCIL PRINTING APPARATUS Original Filed Feb. 5, 1947 2 Sheets-Sheet 2 IN IENTORS B. THOMAS COURTNEY E. M002 HOUSE BY JOHN A TTO/ZA/EY Patented July 28, i953 j UNITED STATES PATENT emu- John B. Thomas, Watertown, Conn., and Courtney E. Moorhouse, West Englewood, N. J assignors to Roto-Matic Screen Printer, 'Ltd., New York, N. Y., a corporation ofllew .York

" Original application February 5,1947, Serial No.

726,504. "Dividedand this application March -3, 1949,Serial N0. 79,412 i I v,

-Ihisinvention relates to an apparatus for printing sheets such as textile fabricwebs, plastic films and paper with the aid of a stencil- For simplicity, suchapparatus will be referredv to hereinafter simply as a "silk screen printing machine, it being understood that said term. is merely a trade designation for a stencil printing machineand does not indicate that the stencil necessarily is of silk.

It is an object of our-invention. to provide a silk screen .printing machine which will print uniformly, clearly and accurately even when run by an unskilled operator. 1

:It isa more specific: object ofour invention, to provide a silk screen printing machine in which the printing table may be adjusted to provide a desirable printing surface of any ,verti-calprofile, even skew, if suchasurfaceisrequired.

:Other 7. objects of ourinvention will in part be filedv February 5, 1947, forStencilPrihtingApparatus, of which the presentapplication'is a division, and in ourco-pending application-Serial? No. 79,413, filed March 3, 1949, for Stencil Printing Apparatus.

,In the accompanying drawings ingwhich is shown one .of the various possible embodiments of..our invention,

Fig. 1 is a.top plan viewof a silk screenprinting machine constructed in accordance with our invention; Y A

Fig. 2 is a front View of said machine;

Fig. 3 is an enlarged sectional view taken substantially along the line 3--3 of Fig. 2;

Fig. 4 is an enlarged sectional view taken substantially along the line 4-4 of Fig. 2;

Fig. 5 is a left-hand side view of theprintin table with portions partly broken away .to show the construction of the table t p; and

7 Fig. 6 is an enlarged sectional v ew taken substantially along the line 6-6 of Fig. 1. v I

Referring now in detail to the drawings, to de notes a silk screen printing machine embodying our invention and comprising a printing table I! to either side of which a supply or take-up reel be employed.

1 claim; (01. 101-407) M, lliis disposed. The printing. table l2 includes a front frame 18 anda rearsframe ZIJinterconnected by'tie rods 22. Saidtable is adapted to. be secured to. a firm support, such as afioor, and is set bymeans of levelling screws 24 so that the top of the. tableis approximately horizontal.

. Thetextile webrto be. printed is adhesively se-x cured to ablanket 26- of. fiexiblematerial capableof being rolled and rerolledmany times without breaking, andyet heavy "enough to maintain its own shape when. printing pressure is. applied thereto. A material. which hasbeen foundsatisfactory for thisv purpose is heavy commercial linoleum. ,Theblanketsare relatively long, for example, seventy-five yards, .one. end of the blanket being secured by a pressuresensitive adhesive tape to one .of the. reels and theother end in like mannerlto the other of the reels. The blanket vpassesacross the tabletop, beingsupportedlthere in a manner. later. described. As the blanket is led. from one to theother of the reels its position in a front-:to-back sense isheld CO1): stant so that successive prints will be in front-toback registration. To this end,.we provide. narrow guide and spacer belts. 28, 30 atthev front. and back of the blanket'adj acent lateral edges thereof. Conveniently, said belts are secured to the undersurface of the blanket; the attachment being' ef-' fected in any suitable manner, forinstance by means of .an,adhesive,.or by mechanical fastening means suchas rivets, or by sewing. Said belts may be made of they same material as .the blanket, i. e., linoleum,,.or any other flexible and relatively strong substance such as rubber alternatively can As theblanket passes from one of the reels to thetable and from the table to theother of the reels the belts engage. two front-to-back registeringfmeans whose construction is best seen in Fig. Each. said means includes a double flanged guide sheave 32 mounted to rotate about ahorizontal axis extending in a front-to-back direction underneath the blanket, Said sheave snugly receives, between its flanges the front guide and spacer'belt 28.;The sheaves arelocated in proximate relationship to the printing table one toeither side thereof ,as seen in Fig. 2. For this purpose saidsheaves' either may be journaled in bearings supportedfrom the. table or from the reel carrying cradles; the-latter type of support being illustrated herein. I I

gjItis; convenient to.'associated saidsheaves with idling rollers which carry the weight of the belt as it approaches and leaves the table. Accordinsly, each sheave 32 is secured to a shaft 34 which also has mounted thereon an idler roller 36. Said idler roller is of reduced diameter at its rear 38 to accommodate the rear guide and spacer belt 30. The idler roller shaft 34 is journaled at its ends in self-align m fl-anged car-- tridge bearings 40 which are secured to a cradle frame 42 for the supply and take-up reels.

Means also is included for holding the blanket down against each idler roller and guide sheave. Such means comprises a pair of keeper wheels '43 rotatably supported on shaft 44, vertically .adjustably bolted to angle brackets l fastened to the cradle frame. Theiront :keeper wheel captively holds the front guide and spaced belt rigid backing member or body '4?! whose tip 41.8v

is either rigid or resilient depending upontthe particular manner in which the .machine is used. Thescraper blade 46 illustrated hereinis -entirely vrigid, being composed, by-way of example, from a .thermosetting plastic. The lower portion of the blade is slightly tapered and the tip 48 thereof rounded as :best seen in Fig. '6. The ends of said blade are .journaled in a pair 'of sblade hangers it! which are supported on a .draw bar 52. The ends "of .the draw bar are mounted :on carriages 54 which ride between rails 56 :extending in a front-.to-backuirection on opposite sides of. the table.

The draw bar can be moved back and forthacross. the stencil :screenfSreither by power, as described :in detail in our co-pending application, Serial No. 726,504, 'or :by hand with the aid of a socket :58 mounted on the. draw .bar and adapted toreceive a handle 8B.

The stencil screen IS constitutes :a apieceof fabric which has per-vious and impervious areas defining a design. The screen has an oblong 4.

shape, being elongated in a .front-to-back direction. The edges of the screen are secured in :a suitable manner, as :by gluing, clamping or stapling, to a stencil screen :frame 52 :of any-selfform-maintaining material, such for example as .3;

wood. When the scraper. is. functioning, the stencil screen rests on a textile web fi l carried by the blanket :26. and it is desired to shift the blanket in order to bring a fresh portion of the web beneath the screen, the screen is elevated, :as :descr-ibedin detail in .our 'co-pending application, :Serial No.

726,504. The blanket is shifted either bythe' hand wheels 66 or by a power drive .as explained fully in our said.co-pendingapplication.

The opposite ends of the blanket 26 are detachably secured, as with pressure sensitive ad-- hesive tape, to reels 68, 18, one of which may serve as the supply reel and the. other-as the take-up reel depending upon the direction of blanket travel.

Pursuant to the present invention, as the blanket passes over the printing tabl-e it rests upon a substantially flat resilient support such as is afforded by a .thi'ck felt pad 172 which inturn is supported on a metal plate =14. said plate can be vertically adjusted at many points When the scraperis idle 4 throughout its area so as to provide the proper type of support for securin a clear and even print over the entire area of the screen. This adjustment is effected by a plurality of tapped socketsilfiheld to the umdersiclelof the plate 14 by flathead'ibo'lts 118 received in countersunk holes in the plate. Each socket fixedly engages, e. g., :by welding, a depending threaded rod which freely passes through an opening in the horizontal -flange of a channel iron 82 running from the front to the back frame of the printing table. Several such channel irons are provided, the same-being spaced-from side-to-side of the printing table and each having many threaded rods 88 passingtherethrough. The rods are vertically adjusted with respect to the channel irons by nuts .84.; that is to say, by turning one of the nuts 84 the associated socket 76 will be raised or lowered and the elevation of the plate at that point correspondingly changed. Lock nuts 86 may bexthreaded on rods -801-underneath the channelirons.

Similarly adjustable types of Supports can-be afforded iior the guide belts 28,;30. .Eachlfl supports-comprise ea -wooden strip .88,. running from side-'to-side of the. machine directly-beneath one of the-belts. The strips aresupported from the :channel irons :82 collars .zefl secu-red to bolts whose heads are received innountereunk holes ,in-the strips and whose .shanksliare connected to the channel irons in the :same manner as therodss8fl.

It will thus be seen that wehave provided .a machine which achieves the several :obiects, of

our-inventionand is well adapted to. meet the.

conditions of practical use.

As various possible embodiments might be made of the above invention, and as various changes might :be. :made in themembodiments above .set forth, :it iszto be understoodthatall matter herein described, or shown in the accompanying drawings, is to .be interpreted as illustrativezandmot in alimiting sense.

Having thus described our invention, we .claim as .newand desire to secure by .LettersPatent:

In combination sin-a ssilkaiscreen printing machine, sa flexible elongated blanket adapted to support a textile 'web,said b'lariket having -:dnwnwardly projecting elements adjacentlits "lateral edges, :a printin table across which the blanket is-adapted to move .and :on wl1ich rests during printing, said *taibledncluding 4a flexible metal plate -.which extends :between -:sa:ld elements .and iscoveredw ith :a resilient .material, means to independently vary the level of different portion .of saidplateadjacent and fintermediate the edges thereof, members at the back and front of said plate for supporting said elements, and means to independently .vary :the

leve1 of different pertions aof said members.

JOHN B. THOMAS. CQURTNEY :E. :MOQRHQUSE.

References Cited in the fileof this patent UNJITED :SZT'AEZES De Save "Dec. -3'1, 194D

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