US2547817A - Squeegee operating and control mechanism - Google Patents

Description

April 3, 1951 s. L. FRANK SQUEEGEE OPERATING AND CONTROL MECHANISM Filed Sept. 25, 1948 2 Sheets-Sheet 1 llllllllllllllllIHHHIIHIIHIHIIIIIF H HTI IHIIIIHIIHIIHIIHHIIIIllllllllllll ll INVENTOR.

STANLEY L. FRANK BY 13mg, fi tbv H/S ATTORNEYS Patented Apr. 3, 1951 UNITED STATES PATENT OFFICE SQUEEG-EE OPERATING AND CONTROL MECHANISM Stanley L. Frank, Oakland, Calif. Application September 25, 1948, 'Serial No. 51,283

10 Claims. 1

My invention relates to screen printing appara- 'tus and more particularly to squeegee operating and control "mechanism for such apparatus.

Among the objects of my invention are:

1) To -provide a novel and improved squeegee operating and control mechanism for screen printing apparatus;

(2) To provide a novel and improved squeegee operating and control mechanism for screen printing apparatus, .in which the squeegee shall automatically reverse at the termination of each stroke;

. (3) To provide a novel and improved squeegee operating and control mechanism for screen printing apparatus which will assure substantially uniform continuous pressure of the squeegee against the screen throughout the effective stroke of the squeegee;

(4 To provideia novel and improved squeegee operating and control mechanism for screen operating and control mechanism for screen printing apparatus, in which the squeegee terminates its stroke in a reversal of position, ready .for the start of its return stroke.

Additional objects of my invention will be brought out in the following description of a preferred embodiment of the same, taken .in conjunction with the accompanying drawings Whereiri- I Figural :is an .elevational .view in .section, taken longitudinally through the screen printing apparatus with my novel and improved squeegee operating and control mechanism installed;

Figure 2 is a fragmentary plan view of the .apparatus of'Figure 1;

Figure 3 .is an elevational View in section, transverselynf the apparatus of Figure 1 and taken in the plane 3-3 of Figure 1;

Figure 4is a three-dimensional view-of .oneend of the squeegee operating and control mechanism of the present invention;

Figure 5 is a view .in section through the squee and control mechanism of Figure ne end thereof in elevation.

Referring ,to the drawings for details of the preferred. embodiment of the present invention, the same is shown installed in conventional screen printing apparatus involving a platen 1 supported one frame 3 to which is .hingedly secured arectangular frame 5 "on. which is stretched a silk screen -'I enaloling the screento be raised and lowered with respect to the surface 01' the platen. 4

Ink or paint 9 "employed in printing is placed on the upper surface of the screen and spread over the surface thereof by means of a squeegee H which is run over the surface of the screen in the process of printing.

A sheet l'3 of blank paper, placed 'upon "the platen beneath the silk screen, will receive such paint as penetrates through the pores of the screen during such movement of the squeegee. By placing a stencil 15 intermediate the screen and such paper, the stenciled information will be reproduced on the paper. The paint in the meantime causes the stencil to efiective'ly adhere to the undersurface of the screen, whereby, upon lifting the screen following a stroke of the squee- 'gee,the paper with its printed information thereon may be freely removed from the platen and a fresh sheet of paper substituted.

The present invention resides specifically in the mechanism for operating and controlling the squeegee, which, in the present invention, is adapted to function on both its forward and return strokes, and is designed to push the ink or paint ahead of it, as I have found this to produce .more uniform results, in that the tendency for a squeegee to ride over the ink supply is thereby minimized.

.Such operatingand control mechanism involves mean'smounted on and extending along eachlongitudinal side of the screen frame for movably supporting .a squeegee carrier assembly. Such supporting means includes a track 11 and associated rack [9 running along the longitudinal side of the screen .frame, and a guide rail 2| running along the inner side of the upper edge of .a side wall 2.3, to fixedly support such guide rail .in parallel relationship .to the track and associated-rack.

The squeegee carrier assembly involves a pair of carriers 25, one for veach end of the squeegee .H which is adapted to span the width of the printin screen. Each such end carrier includes a pair of assemblies, one, 2!, which slidably engages the track for-slidable movement therealong, while the other assembly 129 is resistively supported by the track-engaging assembly and slid- :ably engages the guide rail .2]

With respect to details of construction, the track-engaging (assembly involves a block 3| having a longitudinal groove .in its undersurface permitting the block to straddle the rack and rest upon the track; The corresponding blocks of each carrier are interconnected by an angle iron ve sal of position of the squeegee.

cross-piece 35 spanning the screen frame. Pivotally secured to the corner of each of the aforementioned blocks, on the inner surface thereof serton in a perforation provided in a squeegeev mount for the purpose. Upon raising the squeegee mounts about their pivot axes, it will be apparent that the squeegee will be lifted from its operative position on the screen.

The resistively supported assembly 29 comprising the upper portion of a carrier, comprises a strip 45 having end brackets 41 and 49 adapted to slidably engage the guide rail and thus support the strip for slidable movement adiacent the inner edge of the guide rail. This strip is formed with a longitudinal slot 5! exten ing practically the full length thereof to receive a bolt or machine screw 53 extending downwardly through the slot and threadedly engag ng the bearing block below, such bolt limiting the permissible movement of the strip with respect to the bearing block. l v

The slotted strip carries alon its upper surface adjacent its inner edge. a lift-and-reversing cam 55. This cam is in the form of a flat segment standing on edge, the cam surface being formed by the upper edge of the segment sloping upwardly toward a peak from each end.

Such cam surface is adapted to be en aged by a cam follower or roller 51 which in the operating position of the squeegee, will occupy a position at one end of the cam.

As thus far described, if the upper or cam assembly 29 were held against movement a ong the guide rail, and pressure were brought to bear against the bearing block to produce relative movement between the track engaging assembly and the cam assembly, the squee ee mount at each end of the squeegee will be l fted about its pivot axis as the cam follower on the squeegee mount is forced to ride up the adjacent cam surface toward the peak of the cam: and as the squeegee mounts are thus lifted, the squeegee itself will be tilted upward to a vertical plane and raised above the screen .to the position depicted in Figure 5.

Cont nued relative movement between the two assemblies will cause the ,cam follower to descend on the other s o e of the cam to gradually drop the squeegee back into contact with the screen and reverse its pos tion.

Such revers ng action of the squeegee is only desired however, at the termination of each stroke, and accordingly to secure such acton at the pro er time, I provide a stop pin 59 on, the guide rail at a point approaching the end of each stroke, so that as the cam assemblv strikes or abuts such a stop pin, to halt further movement th eof in the dir ction in whi h it as tra el n 'sufficient additional movem nt of the bear ng block will be ermitted to effect the desired re- It is noted that the cam is not s mmetrical in the embodiment of the invention illustrated. and

this is attributable tothe fact that in the reversed pos tion of the squeegee, it will not necessarily pensate for this condition.

The reciprocating movement of the squeegee is imparted thereto by a rod Bl hingedly secured to the angle iron cross member 35 at the mid-point thereof, such rod constituting either a piston rod or a lever in a power application system.

The squeegee of the present invention is so mounted as to push the ink or paint ahead of it, as distinguished from the conventional method of dragging the ink along with it. A more positive and effective spreading of the coloring material over the screen is thereby assured.

Means are provided for equalizing the movement of the aforementioned end carriers 25 with respect to each other, to assure that one end of the squeegee shall not travel ahead of the other during any portion of its stroke, or, in other words, to maintain the squeegee at all times normal to its direction of movement.

Such means includes an equalizer shaft 63 journalled at each end in one of the bearing blocks. Each such bearing block is formed to provide a chamber for housing a pinion 65 mounted on such equalizer shaft adjacent the associated journalled end and in engagement with the rack. With such equalizer means installed and functioning, one end carrier assembly cannot move ahead of the other during any portion of the stroke of the squeegee, and consequently the squeegee itself will necessaril remain normal to its direction of movement at all times.

During the operating or functioning portion of the squeegee stroke, the squeegee is maintained in proper pressure contact with the screen by providing at each end of the squeegee, suitable means for positively holding the squeegee in the desired pressure contact with the surface of such screen.

Such means includes a pressure rail 61 affixed against the inner edge of the track, and extending substantially, though not quite, the whole distance between stop pins. Affixed to each end of the squeegee bar for cooperation with such rail, is a pressure roller 68 adapted to engage this rail and slide under it at the start of each stroke, the rail being cammed at each end to facilitate such engagement. In this manner, the squeegee will be positively held in its down or operating position at a desired pressure, until such roller rides from under such rail at the other end thereof, which is time to occur just prior to contact of the upper or cam assembly with a stop pin.

As the squeegee is thus depressed into pressure engagement with the screen, the angular rotation of the squeegee about its mounting pins is in a direction tending to reverse the squeegee. To avoid probable reversals of the squeegee under such circumstances, I have found it desirable that the squeegee be temporarily locked in the position it assumes at the end of each stroke so as not to be disturbed when the pressure rollers subsequently engage the pressure rails on the succeeding stroke.

With this in mind, the mounting bracket 41 of the cam assembly is formed with a notch 69 facing the associated squeegee mount 31, which mount is formed with an overhang H adapted to enter the notch at the termination of the return stroke, whereby the mount becomes locked against movement on its pivot axis. During what may arbitrarily be considered the forward stroke, it is contemplated that such locking engagement will over the 'c'am in the DI'DOESSOfIeVBI'SiIIgTthG squee- -it being noted that by this time the squeegee jpressure roller will have moved :out or engagement with the ?pressure 'rail and so will not inter- :dere with such :reversal of thesqueegee.

Following reversal of the squeegee at the .far end of the forward stroke, :a similarulockin of the squeegee :occurs in preparation for the return :stroke. .At this point it is accomplished by pro- ;viding a shoulder 13 :on the squeegee mount, which is adapted to slide linfunder the bracket-49 no "thereby :lock the mount against movement labout its pivot axis. V

:Fhom the above description of myrinvention in its preferred :form, it will be apparent that the same rfulifills .all the objects recited therefor and while I have :diSjClOSEd my invention in its pre- {Ierred :form and in considerable detail, the same is subject to alteration and modification without departing from the underlying principles thereof. 1, accordingly, do not desire to be limited in my protection to such details, except as may be necessitated by the appended claims.

.I claim:

1. Squeegee operating and control .mechanism ior screen printing apparatus of the type involving a platen and a removable screen thereon, comprising track means mounted on said table and extending along each longitudinal side of :such screen for movably supporting a squeegee carrier assembly; a squeegee carrier assembly zmovably supported thereon, said carrier assem ablytinvolving a carrier for each end-of such squee- ;gee and a cross-bar interconnectin the same; each of said end carriers including an assembly :sildably engaging said track means, and lift-andireversing cam means mounted on said track means engaging assembly; each of said track means engaging assemblies havinga cam follower Weir "lower associated therewith, :to eengage .and aside ill) engageable with said lift-and-reversing cam 7 :means; meansfor reciprocally moving said squeeegee carrier assembly on said track means; [and means for .causing relative movement between said .cam means and said track means engaging assemblies as the end carriers approach the termination of reach stroke.

'2. Squeegee operating and control mechanism for screen printing apparatus of the type involving a platen and a removable screen thereon, comprising track means extending along each longitudinal side of such screen for movably supporting ia squeegee carrier assembly; a squeegee icarrier assembly movably supported thereon, said carrier assembly involving-a carrier for each end of such squeegeeand a cross-bar interconnecting thesame; each of said end carriers including an assembly slidably engaging said track means and lift-and-reversing cam means resistively associ- :ated with said track means engaging assembly; 1a. squeegee end-supporting bracket secured :in each of said track means engaging assemblies and having a cam follower engageable :with said 'lift and-reversing cam means; means for reciprocally moving said squeege'ecarrier assembly on :said track means; means for causing relative movement betweensaid cam means and said track ameans'engaging assembliesas the .end' carriers approach the termination of each stroke; and

:means for holdin a squeegee in desired pressure engagement with such screen during those portions of its strokes intermediate .suc'h period .of relative movement between said cam means and ,said track means engaging assemblies.

.3; Squeegee operating and control mechanism or screen printing apparatus of the type involving :a "platen and ca removable screen thereon, comprising :track means mounted on said platen "and extending :along each longitudinal side .of such screen for imovably supporting a .squeegee carrier assembly; :a squeegee carrier assembly movablysupported thereon, a carrier for each end of suchsqueegee and a cross-bar interconnecting the same; each of said "end carriers including an assembly .slidably engaging said track means-and lift-and-reversing cam means resistively mounted on said track means engaging assembly; a squeegee end-supporting bracket secured in each of said track mean engaging assemblies and having a cam follower engageable with said lift-andreversing cam means; .means for reciprocalh "moving said squeegee carrier assembly on said track means; and means 'for causing relative vtmovement between said cammeans and said track means engaging assemblies as the end carriers 'approach'the termination of each stroke. Y

4. Squeegee operating and control mechanism "for screen printing apparatus of the type involvin a platen and a removable screen thereon,

comprising track means extending along each longitudinal side of such screen for movably supporting a squeegee carrier assembly; a squeegee carrier assembly movably supported thereon and including a carrier for each end of such squeegee,

each of said end carriers including an assembly slida'bly 'en'gagingrsaid track means, and lift-andment of both said end carriers with respect to each other; and means for causing relative movement between said cam means and said track means engaging assemblies as the end carriers approach the termination of each stroke.

5. Squeegee operating and control mechanism for screen printing apparatus of the type involving a platen and a removable screen thereon, comprising track means extending along each longitudinal side of such screen for movably supporting a squeegee carrier assembly; a squeegee carrier assembly movab y supported thereon said carrier assembly involving a carrier for each end of such squeegee and a cross-bar interconnecting the same; each of said end carriers including an assembly slidably engaging said track means, and lift-and-reversing cam means resistively mounted on said track means engaging assembly; a squeegee end-supportin bracket secured in each of said track means engaging assemblies and having a cam follower engageable with said lift-andreversin cam means; means for reciprocally moving said squeegee carrier assembly on said track means; means for equalizing the movement of both said end carriers with respect to each other; and "means for causing relative movement between said cam means and said track means engaging assemblies as the end carriers approach 'thetermination of each stroke.

SJSqueegee operating and control mechanism for screen printing apparatus of the type involving a platen-and a removable screen thereon,

comprising means extending along each longi- 'tudinal side of said screen for movably supporting a sq eegee carrier assembly. said means including a track along each of said longitudinal sides, a squeegee carrier assembly 'movably mounted on said tracks, said carrier assembly involving a carrier for each end of such squeegee; each such end carrier including a pair of assemblies, one slidably engaging such track and the other resistively supported by said track engaging assembly, a lift-and-reversing cam in said resistively supported assembly, a squeegee end-supporting bracket pivotally secured in each of said track engaging assemblies and having a cam follower engageable with said lift-andreversing cam, and a cross-bar interconnecting said track engaging assemblies; means for reciprocally moving said squeegee carrier assembly on said tracks; and means disposed in advance of the termination of each stroke of said squeege carrier assembly for restraining further movement of said resistively supported assemblies as said assemblies approach the termination of each stroke, whereby continued movement of said track engaging assemblies to the end of each stroke will cause said lift-and-reversing cams to lift and reverse a squeegee affixed to said squeegee end-supporting brackets.

'7. Squeegee operating and control mechanism for screen printing apparatus of the type involving a platen and a removable screen thereon, comprising means extending along each longitudinal side of said screen for movably supporting a squeegee carrier assembly, said means including a track along each of said longitudinal sides and a guide rail fixedly supported in parallel relationship to said track, a squeegee carrier assembly movably mounted on said tracks, said carrier assembly involving a carrier for each end of such squeegee; each such end carrier including a pair of assemblies, one slidably engaging such track and the other resistively supported by said track engaging assembly and slidably engaging said guid rail, a life-and-reversing cam in said resistively supported assembly, a squeegee endsupporting bracket pivotally secured in each of said track engaging assemblies and having a cam follower engageable with said lift-and-reversin cam, and a cross-bar inter-connecting said track engaging assemblies; means for reciprocally moving said squeegee carrier assembly on said tracks; means for equalizing the movement of said end carriers with respect to each other; and means disposed in advance of the termination of each stroke of said squeegee carrier assembly for restraining further movement of said resistively supported assemblies as said assemblies approach the termination of each stroke, whereby continued movement of said track engaging assemblies to the end of each stroke will cause said lift-and-reversing cams to lift and reverse a squeegee affixed to said squeegee end-supporting brackets. I

8. Squeegee operating and control mechanism for screen printing apparatus of the type .in-

volving a platen and a removable screen thereon, comprising means extending along each longitudinal side of said screen for movably supporting a squeegee carrier assembly, said means including a track and a rack along each of said longitudinal sides and a guide rail fixedly supported in parallel relationship to said track, a squeegee carrier assembly movably mounted on said tracks, said carrier assembly involving a carrier for each end of such squeegee; each such end carrier including a pair of assemblies, one slidably engaging such track and the other resistively supported by said track engaging assembly and slidably engaging said guide rail, a 'lift-and-reversing cam in said resistively supp'orte'd' assembly, a squeegee end-supporting bracket pivotally secured in each of said track engaging assemblies and having a cam follower engageable with said lift-and-reversing cam; means for reciprocally moving said squeegee carrier assembly on said tracks; means for equalizing the movement of said end carriers with respect to each other, said means including an equalizer shaft terminating at its ends in said track en'- gaging assemblies, and pinions carried by said shaft in meshing engagement with said racks; and means disposed in advance of the termination of each stroke of said squeegee carrier assembly for restraining further movement of said resistively supported assemblies as said assemblie approach the termination of each stroke, whereby continued movement of said track engaging assemblies to the end of each stroke will cause said lift-and-reversing cams to lift and reverse a squeegee ainxed to said squeegee endsupporting brackets.

9. Squeegee operating and control mechanism for screen printing apparatus of the type involving a platen and a removable screen thereon, comprising means extending along each longitudinal side of said screen for movably supporting a squeegee carrier assembly, said means including a track and a rack along each of said longitudinal sides, a squeegee carrier assembly movably mounted on said tracks, said carrier assembly involving a carrier for each end of such squeegee; each such end carrier including a pair of assemblies, one'slidably engaging such track and the other resistively supported by said track engaging assembly, a lift-and-reversing cam in said resistively supported assembly, a squeegee end-supporting bracket pivotally secured in each of said track engaging assemblies and having a cam follower engageable with said lift-and-reversing cam, and a cross-bar interconnecting said track engaging assemblies; means for reciprocally moving said squeegee carrier assembly on said'tracks, said means including an actuating rod secured at one end to said cross-bar; means for equalizing the movement of said end carriers with respect to each other, said means including an equalizer shaft terminating at its ends in said track engaging assemblies, and pinions carried by said shaft in meshing engagement with said racks; and means disposed in advance of the termination of each stroke of said squeegee carrier assembly for restraining further movement of said resistively supported assemblies as said assemblies approach the termination of each stroke, whereby continued movement of said track engaging assemblies to the end of each stroke will cause said lift-and-reversing cams to lift and reverse a squeegee aifixed to said squeegee end-supporting brackets.

l0. Squeegee operating and control mechanism for screen printing apparatus of the type involving a platen and a removable screen thereon, comprising means extending along each longitudinal side of said screen for movably supporting a squeegee carrier assembly, said means including a track and a rack along each of said longitudinal sides and a guide rail fixedly supported in parallel relationship to said track; a squeegee carrier assembly movably mounted on said tracks, said carrier assembly involving a carrier for each end of such squeegee; each such end carrier including a pair of assemblies, one slidably engaging such track and the other resistively supported by said track engaging assembly and slidably engaging said guide'rail. a

lift-and-reversing cam in said resistively supported assembly, a squeegee end-supportingbracket pivotally secured in each of said track engaging assemblies and having a cam follower en- 10 whereby continued movement of said track engaging assemblies to the end of each stroke will cause said lift-and-reversing cams to lift and reverse a squeegee afiixed to said squeegee endgageable with said lift-and-reversing cam, and 5 supporting brackets.

a cross-bar interconnecting said track engaging assemblies; means for reciprocally moving said squeegee carrier assembly on said track's, said means including an actuating rod secured at STANLEY L. FRANK.

REFERENCES CITED The following references are of record in the one end to said cross-bar; means for equalizi g l0 file of thi patent:

the movement of said end carriers with respect to each other, said means including an equalizer shaft terminating at its ends in said track engaging assemblies, and pinions carried by said shaft in meshing engagement with said racks; 15

and means disposed in advance of the termination of each stroke of said squeegee carrier assembly for restraining further movement of said resistively supported assemblies as said assemblies approach the termination on each stroke, 20

UNITED STATES PATENTS Number Name Date 913,274 Erler Feb. 23, 1909 1,589,546 Nichols June 22, 1926 2,207,818 Perry et a1. July 16, 1940 FOREIGN PATENTS Number Country Date 345,961 Germany Dec. 21, 1921

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