US2458773A - Screen printing machine - Google Patents

Description

Jan. 11, 1949. R. F. FOARD SCREEN PRINTING MACHINE 6 Sheets-Sheet. 1

Filed Feb. 18, 1946 g ZIvWq/HM EOBEET F FbAED Jan. 11, 1949. R. F. FOARD SCREEN PRINTING MACHINE 6 Sheets-Sheet 2 Filed Feb. 18, 1946 %FF5AED FIG 4 Jan. 11, 1949. R. F. FOARD SCREEN PRINTING MACHINE 6 Sheets-Sheet 3 Filed Feb. 18, 1946 Flam f glzwcmicw Easier FFZA/QQ Jan. 11, 1949. FOARD 2,458,773

SCREEN PRINTING MACHINE 6 Sheets-Sheet 4 Filed Feb. 18, 1946 awuwm EOBEET' FFOAED Jan. 11, 1949. R. F. FOARD SCREEN immune momma 6 Sheets-Sheet 5 Filed Feb. 18, 1946 Jan. 11, 1949. oA p 2,458,773

SCREEN PRINTING JMCHINE Filed Feb. 18, 1946 e Sheets-Sheet s Patenterl Jan. 11, 1949 2,458,773 SCREEN PRINTING MACHINE Robert F. Foard, Los Angeles, Calif. Application February 18, 1946, Serial No. 648,426

18 Claims.

My invention relates to screen printing machines, and among the objects of my invention are:

First to provide a screen printing machine which is an improvement of my screen printing apparatus described in Patent Number 2,206,176, issued July 2, 1940, in that many of the operations performed manually by my. previous machine are accomplished automatically,

Second, to provide a screen printing machine which is particularly adapted for multiple color screen printing, and which is so arranged that various sets of screen printing frames may be interchanged without disturbing the registry between the frames of each set; thus, by providing several sets of screen printing frames each set with correspondingly different designs, one set may be quickly removed and another substituted and printing continued with the new design,

Third, to provide a screen printing machine wherein a series of screen printing frames are automatically moved in sequence between a retracted, stacked position and an extended, printing position; this being accomplished in such a manner that each frame in its printing position is in registry with the designs on the preceeding or succeeding frames, and furthermore is moved relative to the material to be printed in such a manner that any relative sliding movement that might result in smearing the design freshly printed on the material is avoided.

Fourth, to provide a screen printing machine wherein the screen frames when not employed in a printing operation are stacked in an elevator, the elevator being movable to bring the frames in sequence into alinement with an ejecting and retracting mechanism, and wherein means are provided to prevent operation of the ejecting and retracting mechanism or the elevator unless the screen frames are in their desired position.

Fifth, to provide a screen printing machine which may be employed to print individual pieces, sometimes called blanks (such as towels) which are held in place by retainer frames such as shown in my aforementioned patent, or to print on uncut or bolt material by employment of the devices such as depicted in my patent entitled: Means and method of printing on cloth, Patent Number 2,369,290, issued February 13, 1945 or with other means for holding the cloth or other material in place or feeding the material into printing position.

Sixth, to provide a screen printing machine which is relatively simple in its operation so that it may be operated by a workman with little experience and no great technical knowledge.

Seventh, to provide a screen printing machine wherein the squeegee operation may be carried out manually.

With the above and other objects in view as may appear hereinafter, reference is directed to the accompanying drawings, in which:

Figure 1 is a fragmentary top view of my screen printing machine, the printing frame ejecting means being omitted.

Figure 2 is a fragmentary side view thereof including the ejecting means, portions of the elevator housing being broken away to facilitate the illustration, and the various parts shown in the position ready for ejection of a screen printing frame.

Figure 3 is a sectional view in plan of the elevator and its housing taken substantially through 33 of Figure 2.

Figure 4 is a sectional view thereof taken through 4-4 of Figure 3.

Figure 5 is a rear elevational view of the elevator housing with its back cover partially broken away.

Figure 6 is an enlarged fragmentary partial elevational, partial sectional view of my screen printing machine taken through 6-6 of Figure 2 showing particularly the registering or master frame with a screen printin frame therein and retained in its registering position.

Figure 7 is a further enlarged sectional view of one of the printing frame registering rams employed to urge the screen printing frame laterally into its registering position.

Figure 8 is a fragmentary end elevational view of the master frame and its elevating unit taken from 8-8 of Figure '7.

Figure 9 is a partial sectional, partial elevational view of the ejecting means taken substantially along the line 9-9 of Figure 2, showing the ejecting means in the course of its retracting movement as it is about to release from the screen printing frame, or just after engaging the frame depending on the direction of movement.

Figure 10 is an enlarged sectional view thereof taken through llll0 of Figure 9 indicating by dotted lines the fully retracted position of the ejecting means.

Figure 11 is a partial elevational, partial sectional view thereof taken through Il-ll of Figure 9, but showing the ejecting means just before engaging or just after disengagin the screen printing frame, depending on its direction of movement.

Figure 12 is a wiring diagram illustrating the interlocking and interdependent arrangements of the various actuating mechanisms whereby they are caused to operate in proper sequence and are prevented from operating unless related elements of the machine are in proper position.

An elevator housing I is provided which is in the form of a rectangular box with corner posts 2 which serve as vertical rails for guiding therein an elevator cage 3. The elevator cage 3 is likewise rectangular in form and is provided withvertical corner posts 4 which confront the posts 2. Roller guide units each including rollers bearing in two directions against the corresponding post to retain the elevator in position.

The elevator cage is provided at each corner with keeper bars 6 having a series of vertically disposed notches, one for each screen printing frame carried by the elevator. The notches of the keeper bars 6 engage rollers 1 carried by latch bars 8 supported horizontally on opposite sides of the housing I in guides 9. The latch bars 8 are arranged in opposed pairs connected by links III to the extremities of a rocker arm II. Each rocker arm is joumaled relative to the housing I and its shaft also carries a lever I2.

The two levers thus provided are connected by rods I3 to lever arms extending from a rocker shaft I4 positioned under the elevator cage 3, and journaled between bearings on uprights of the housing I. The rocker shaft is connected by another lever arm to a piston rod I5 extending upwardly from an actuating cylinder I6 operated by air or fluid. The keeper rollers are yieldably urged against their respective latch bars 8 by a spring I1 or springs suitably connected with the mechani cal train between the actuating cylinders and the latch bars, for example, the spring may be disposed around the piston rod I5.

The elevator cage 3 is raised by an elevating cylinder I8 from which extends an elevator stem l9 which engages the under side of the elevator cage. The elevating cylinder is employed to lift the elevator until the latch rollers 1 engage a lower or selected set of notches provided in the keeper bars .6. The cage is then lowered in stages, by means (described hereinafter) which control the actuating cylinder is for the latch rollers 1. The raising cylinder may be provided with a suitable throttle control, not shown, to control the rate of descent of the cage. Also, if desired, counterbalance weights, not shown, may be so connected to the cage as to partially support its weight.

The elevator cage 3 is open at its forward and rearward ends, and its side walls are provided with a series of tracks having suitable stops 2I at their rear extremities. The tracks 20 slope downwardly from the front to the rear end of the cage. The tracks may be formed of angle members and may include rollers, if desired. The series of tracks support in stacked relation several screen :printing frame units 22.

Each screen printing frame unit 22 includes a rectangular outer frame 23 formed of angle iron in which is set an inner frame 24. The inner frame is preferably formed of wood reinforced at its corners. Each inner frame 24 is adiustably .secured in place by quoins 26. Each inner frame 24 is covered across its under side with a printing screen 24a containing a design registerable with designs contained on the other screens. As will be brought out hereinafter, the inner frames are so adjusted by the quoins relative to the outer frames that their respective printing screens 24a are located in proper registry with each other, when the outer frames are placed in predetermined positions over the material to be printed. The inner screen is restrained against upward displacement by suitable overhanging lugs 23a.

Extending forwardly of the housing I is a master frame 21 which is adapted to receive in se-- quence the printing frame units 22. The master frame is essentially U-shaped with its open end directed toward the housing I. Extending in offset relation from the open end of the master frame are pivot arms 28 which extend on either side of the housing I and are journaled thereto. Compensator springs 29 partially support the weight of the master frame.

The two sides of the master frame which are formed of angle members constitute tracks and guides 30 which receive the printing frame units and the master frame is so pivoted that the tracks 30 may be brought into alinement with one of the tracks 20 depending upon which set of keeper notches support the latch rollers 1. The extended end of the master frame is provided with a stop 3| to limit election and a suitable guard 32 to prevent upward movement of the printing frame units and retain them in a position suitable for printing.

Centered on the outer end of the master frame 21 is a bracket 33 to which is hinged a depending elevating rod 34. The elevating rod is guided between centering rollers 35 and is caused to raise and lower by means of an actuating cylinder 38. The elevating rod 34 is equipped with a stop 36 which is engaged by a latch 31 for holding the master frame in its proper alinement with the tracks of the elevator cage as shown by solid lines in Figure 2. As will be brought out hereinafter the master frame during its upward movement raises above this normal position as indicated by the dotted lines A in Figure 2, and is drawn downwardly to its printing position indicated by dotted lines B in Figure 2.

The master frame 21, by reason of its pivotal connections with the housing I through arms 23 and its connection with the elevating rod 34 guided by the rollers 35 always occupies the same position when depressed.

A suitable printing table C is positioned under the master frame. The printing table is provided with suitable means, not shown, for holding the material to be printed in fixed relation to the master frame 21. Such means may take the form of clamping frames such as shown in my previous Patent 2,206,176, particularly if the screen printing is to be performed on cloth. Or, such means may be arranged to advance cloth in bolt form by stages across the table, as shown in my Patent 2,369,290. It is suflicient for the purposes of this case that the material to be printed whether cloth or paper or other material is retained in a fixed position while a plurality of colors are applied thereto by a succession of printing frame units delivered to the master frame 21. Stops 21a as shown in Fig. 8 may be provided on the table C to engage the extended corners of the master frame 21 so that the master frame is level or parallel to the material to be printed and the printing screen is in the correct printing position.

By reason of the fixed relation between the master frame and the material being printed, it follows that if printing frame units are disposed in a fixed, predetermined position in the master frame, they may be adjusted by the quoins 26 until each of their printing screens register with each other on the work. Such registry is accomplished by insuring that each printing frame unit bears against the stop 3| and against the side wall of one of the tracks 30. This is accomplished by means of force applied by the printing frame ejector, to be described hereinafter, holding each frame against the stop 3|; and by means of ram units 39 mounted along one of the tracks for urging the frames against the side wall of the opposite track.

Each ram unit 39 comprises an actuating cylinder extending laterally from one of the tracks and a ram stem 46 adapted to move into the master frame to engage the corresponding side of the screen printing frame unit and cause the frame unit to assume the position shown in Figure 6.

The several printing frame units are ejected from and retracted unto the elevator cage 2 by an ejector unit 4|. The ejector unit includes an operating cylinder 42, the ends of which are fitted with snubber cylinders 46 and 44 having bores of smaller diameter. A piston 45 reciprocates in the cylinder 42 and is provided with a piston rod 46 which extends through a packing gland 41 provided in the forward snubber cylinder 46. Pistons 46 and 49 extend forwardly and rearwardly respectively from the piston 45 and are adapted to enter the respectively snubber cylinders 43 and 44 as the piston 45 approaches the extremities of its movement, thereby to snub or cushion its movement.

The ejector unit is controlled by a four-way control valve 56 designed to supply air or other fluid or liquid to either end of the cylinder 42 through supply lines 5|. Bypass lines 52 extend from the extremities of the supply lines 5| to the extremities of the snubber cylinders 43 and 44 and are provided with throttle valves 63 so that the snubbing action ma be regulated.

The elector unit 4| is mounted for slight pivotal movement on forward supports 54 and is yieldably supported at its rearward end through springs 54a on a rear post 54b. The mounting is such that the piston rod 46 alines with the particular printing frame unit 22 which may be in alinement with master frame 21. The forward end of the piston rod 46 is provided with a head structure 55 which terminates in a jaw or yoke 56 adapted to fit under and over a corresponding grip bar 51 secured to the rear side of the alined screen printing unit 22 by spring mountings 56. A grip bar 51 is provided on each frame 22.

In order to retract the printing frame units 22, a latch lever 59 is carried by the head structure 55. The latch lever includes a latch roller 66 which is adapted to drop over the grip bar 51 as shown in Figures 9 and 10, the latch lever being urged in this direction by-a spring 61. The latch lever 59 is provided with a trip roller 62 positioned to engage a cam tip 63 at the extremity of a bracket 64 extending forwardly under the piston rod 46.

The proportions of the various co-acting parts are such that as the printing frame unit 22 reaches its rearward position, the latch lever 59 is raised from its latching position shown in Figure 10 to the elevated position shown in,'Figure 11 thereby releasing and clearing the corresponding frame unit. In order to insure proper engagement between the jaw 56 and grip bar 51 and to guide the latch roller 66 over the grip bar 51 suitable cam elements 65 are.provided on the rear sides of the grip bars 51.

The various operating elements of my screen printing machine are electrically controlled to operate in proper sequence and certain of the operating elements are protected from operating at the wrong time or when related parts are in the wrong positions by safety devices. Reference is now directed to Figure 12 which illustrates by electrical diagram the interrelation of the various operating elements.

The ejector unit 4| and elevator latch release cylinder |6 are controlled by a relay 66, having several pairs of contacts. A normally open pair of contacts 61 controls an ejecting solenoid 66 associated with the control valve 56 to cause the piston rod 46 to elect a printing frame unit; and a normally closed pair of contacts 69 controls a retracting solenoid 16 operating in opposition to the solenoid 66 to cause the piston rod 46 to retract.

The head structure vlded on one side with a cam 1| which is adapted to engage and close, as the piston rod 46 moves to its retracted position, an ejector switch 12 which completes a circuit through the coil of the relay 66 to close contacts 61 and open contacts 69. v The switch 12 is mounted on the bracket 64. In Figure 12 the cam 1| is shown just before it closes switch 12. Upon energizing the relay 66, a pair of holding contacts 16 are closed which maintains the relay coil in circuit.

In order to prevent premature operation of the ejector unit, certain safety switches are arranged in series therewith; Mounted on the elevator cage 3 at the rear end thereof is a series of elevation registry cams 14. These engage in succession an elevation registry switch 15 whenever the notches of the latch bars are resting on latch rollers 1 and a printing frame unit is in registry with the master frame 21, and the ejector unit. In addition, each printing frame unit when in its retracted position engages and closes a frame retraction safety switch. 16, there being one switch for each frame. The switch 15 and the switches 16 are in series with each other and with the ejector switch 12, as well as the coil of the relay 66. These switches 15 and 16, or at least the switches 16, are, of course, bypassed by the holding contacts 13 so that the relay will not be deenergized when a. frame is being ejected.

The elevator cage 6 drops stage-by-stage from its upper position under control of the latch release cylinder l6. The cylinder is controlled by a two-way valve 11 operated by a solenoid 16. When the solenoid 16 is de-energized thepiston rod I5 is extended and the latch rollers 1 support the elevator cage; when the solenoid is energized the rod I5 is retracted, releasing the elevator cage. The solenoid 16 is. energized by an elevator latch switch 19 supported with the switch 12 on the bracket 64. The switch 19 is so positioned that it is engaged by the cam 1| after the ejector head structure 55 has cleared the elevator cage 3 and is free of the printing frame units 22 and grip bars 51, but before the switch 12 is closed. Due to the snubbing action of the cylinder 44 and plunger 49 the movement of the piston rod 46 is sufficiently slow, that the elevator cage 3 has dropped sufficiently to open safety switch 15; however, switch 19 is again opened before the elevator cage has settled to the next set of notches. As an added safety measure, the switch 15 as well as the frame retraction safety switches 16 are disposed in series with the elevator latch switch 19 through solenoid 16. Furthermore, a relay 86 is provided which is energized by a switch 6| mechanically but not electrically connected with the switch 19 so as to be closed when switch 19 is closed. The relay 66 is provided with a pair of normally closed contacts 62 which are opened when solenoid 66 is energized. The contacts 62 are in series with switch 12 so that relay 66 cannot be energized when relay 66 is energized. In addition, the relay 66 is provided with a holding circuit including contacts 66 and a contact 64 incorporated in the switch 15 which contact is closed, except when the cam roller of switch 15 is on cam 55'of the ejector unit is pro- 14. Thus irrespective of the timing of the rearward movement of the ejector and the downward I movement of the elevator there is no danger of accidental outward travel of the ejector before the printing screen units are in their proper positions.

Still further, it is desired to close the circuit to the solenoid I8 only during retraction of the ejector piston rod; consequently, the relay 66 is provided with a pair of normally closed contacts 85 in series with the switch 19. Thus, when the relay 66 is energized, the solenoid I8 cannot be energized.

The elevator cage 3 is raised by operation of a two-way valve 9I controlled by a solenoid 92. The valve 9| supplies fluid to the elevator cylinder I8. After the uppermost printing frame 22 has been retracted, that is the frame shown in alinement with the master frame 21 and ejector piston head 55 in Figure 2, and the elevator latch release switch I9 is closed, the elevator cage settles onto a limit switch 93 which closes the coil of a multiple contact relay 94. This closes a pair of holding contacts 95 to maintain the coil of the relay in circuit, and in addition closes contacts 96 in series with the solenoid 92, and completes a circuit therethrough to actuate the elevator cylinder I8.

The relay 94 is provided with a. pair of normally closed contacts 91 which are opened when the relay is energized. These contacts are in series with the ejector switch 12 so that during upward travel of the elevator cage, the relay 66 is de-energized. 7

When the elevator cage has been raised until the lowermost notches in the keeper bars 6 are above the latch rollers I, the cage engages a limit switch 99 which is normally closed and in series with the holding circuit for the relay 94. Upon tie-energizing the relay 94, the elevator cage settles until limited by the lowermost set of latch notches and the lowermost screen printing frame unit 22 is in position for ejection. When this position is reached, the circuit through the why 66 is cleared and ejector unit ejects the lowermost frame unit. I

Inasmuch as it is often desirable to print with less than the maximum number of colors of which the screen printing machine is capable, the upper limit switch 99 may be arranged to be moved downwardly to selected lower positions as indicated by dotted lines in Figure 12 so that; for example three, two or a single color may be printed in place of the four.

Each frame unit 22 is ejected until its forward end engages the stop 3I. A switch I is associated with the stop 3I and is closed when engaged by a frame unit 22. The switch I00 energizes a solenoid IOI which retracts the. latch 31. The latch 31 on retracting closes a switch I02, which controlsa solenoid I 03. The solenoid when energized, actuates a master frame depressing valve I04. The valve I04 is a two-way valve so connected with the master frame that the control cylinder 38 is caused to draw the master frame downwardly when the solenoid I03 is en ergized.

The stop 36 is provided with a cam lug which engages a cam switch I05 to hold the switch open when the master frame is in the region of its normal position. The switch I05 closes when the stop 36 is drawn downwardly. The switch I05 controls a circuit to a solenoid I06 which in turn controls a two-way valve I01, The valve I01 controls the ram units 39. The ram units 39 immediately thrust outwardly the slight distance required for engagement of the frame unit with the opposite tract of the master frame, during which time the ejector unit holds the frame unit in engagement with the stop 3|. This movement takes place before the master frame and printing frame reach printing position. (The dotted line position B, in Figure 2.)

The master frame 2'! with its screen printing frame unit 22 in predetermined relation therein remains depressed in screen printing position on the work placed thereunder while squeegees, not shown, are employed to work dye or ink through the screen. The squeegee operation may be performed manually.

It should be noted that the slight lateral or vertical movement of the head structure required to accommodate the ejector unit to the movements of the master frame is within the flexibility or play made possible by the pivotal mounting on support 54 and the springs 54a of the ejector cylinder so that the ejector unit maintains the required pressure on the printing frame 22 durin the squeegee operation. This pressure may be limited by the sprin mountings 58 assocated with each printing frame unit.

After completion of the squeegee operation, if manually performed, a manually operated switch H0 is closed. If the squeegee operation is performed automatically the switch IIO may be automatically closed, In either case the switch IIO closes a circuit through a master frame raising relay I I I, and through a pair of holding contacts II2 for maintaining the relay energized after opening of switch H0. The relay III is provided with a pair of normally closed contacts H3 in series with the solenoid I03 of the frame depressing valve I04 so that this solenoid is de-energized. A pair of normally open contacts II4 are closed by energization of relay III and complete a circuit through a solenoid II5 which controls a frame elevating valve II 6 so connected as to raise the rod 34 and consequently raise the master frame and printing frame clear of the work.

The master frame 21 is preferably raised above its normal position as determined by the stop 36 and latch 31; that is, to the position A shown in Figure 2. On raising to the position A, a switch I I1 positioned above the latch 31 is opened by the top'36. The switch I I! is in series with the coil of the ejector relay 66 so that on opening of switch II! the relay 66 is de-energized causing the ejector unit to retract the printing screen 22. The switch III is also in series with the coil of master frame raising relay III so that this relay is also de-energized. This causes the registering ram units 39 to release the printing frame and to open both depressing and raising valves I04 and I I6 so that the master frame can settle until limited by the stop 36 engaging the latch 31. This movement is aided by the weight of the master frame and the printing frame unit therein, the printing frame being retained therein by the ram units 39 until the switch I05 is opened.

In order to render the switch I00 inoperative when the printing frame unit 22 is intended to withdraw from the master frame, the relay III is provided with a pair of contacts I20 which energizes a delay open relay I'2I, having contacts I22 in series with switch I00. The relay I2I holds contacts I22 open after de-energization of relay II I for a'period sufficient to insure clearance of switch I00.

At times it is desirable to restrain the ejector unit; for example while arranging material to be printed if this operation is not completed in the frames to be ejected, but without causing the master frame to be depressed. This may be accomplished by preventing operation of the switch I00, why a switch H9 in series therewith may be opened. Such switch may be under the control of an automatic work feeding means or manually controlled or both.

The interchangeability of different sets of frame units is an important feature of my invention, for such change may be made without disturbing the-registry between frame units of a given set; that is, the set may be later reinserted without impairing registry. The printing screens are rather delicate and need frequent care and repair.

Should one screen become damaged, it is merely necessary to remove the set, replace by another and continue printing with a similar or different design as desired, while the first set is being repaired. Such interchanging of frame sets requires only a few minutes.

Operation of my screen printing machine by means of the mechanisms and circuits hereinbefore described is essentially as follows:

The screen printing frame units are fed in sequence to and retracted from the master frame by the combined but alternate action of the ejector unit and the downward stage-by-stage movement of the elevator.

Each printing frame unit as it is extended into the master frame is oriented therein against the extremity and one side thereof sothat it may be depended upon to always assume the same position in the master frame. Each printing frame moves into the master frame while the master frame is elevated clear of' the material to be printed. After being oriented each printing frame is depressed into printing relation with the work material and held there until a squeegeeing operation, either manually or automatically performed, is completed.

After the squeegee printing operation, the printing screen is raised by the master frame about the fulcrum axis of the arms 28 which lifts the printing screen directly away from the freshly printed surface, the outer end is lifted higher than the inner end to effect a clean stripping action even though the material should tend to stick and rise slightly with the printing screen. The extra upward movement of the master frame from its normal position to the maximum position indicated by A in Figure 2 insures the correct stripping action without necessitating the master frame and screen printing frame tracks to be tilted at an excessive angle.

In this regard, it should be noted that enough dye or ink is carried within the screen printing frames to make a number of prints before new dye or ink must be added so that the printing frame while in a stacked position in the elevator cage and also while in the master frame are not carried at an excessive slope.

While my screen printing machine is particularly intended for the use of printing members which arev in fact screens however, it is equally applicable to the use of printing stencils, therefore the term screen as used herein shall be deemed to include stencil.

Various changes and alternate arrangements 10 may be made within the scope of the appended claims, in which it is my intention to claim all novelty inherent in the invention as broadly as the prior art permits.

I claim:

1. In a screen printing machine having combination with a work area adapted to receive material to be printed upon, the machine including a master frame extending over said work area, electrically controlled means at one end of the machine for raising and lowering said master frame, said master frame having a U-shape and when it is lowered' it is adapted to occupy a predetermined relationship with respect to material on said work area, an elevator type magazine means adapted to carry a plurality of screen printing frames, automatic means for feeding said screen printing frames in sequence into said master frame and for returning each printing frame to its respective place in the magazine means, and means for positioning each screen printing frame in a predetermined relation with said master frame.

2. In a screen printing machine, the combination with a work area adapted to receive material to be printed, of: a master frame extending over said work area and having rails upon which to guide frame units; remote controlled means for raisingand lowering said master frame, said master frame, when lowered adapted to occupy a predetermined relation with material on said work area; a plurality of screen printing frame units, each including an outer frame and an inner frame, the inner frame being covered with design bearing screen printing material, and means for adjusting the position of said inner frame relative to said outer frame; means adapted to carry said screen printing frame units; means for feeding said frame units in sequence to the rails of said master frame; and means for positioning each frame unit in a predetermined relation with said master frame, whereby upon adjustment of the inner frames of said frameunits the designs on the screen material may be brought in registry with each other and with work material on said work area.

3. A multiple screen printing machine comprising a plurality of screen printing frames, each frame having a printing screen bearing designs adapted to be brought into registry over a common area; a work holding device presenting a common area for printing purposes, an elevator means in a housing adapted to carry said printing frames in stacked relationship, a master frame pivoted to the elevator housing and positioned to receive printing frames from said elevator means, means for shifting said elevator means to bring selected printing frames into allnement with said master frame for delivery thereto, and self-operating means for effecting ejection of said printing frames as predeterminately selected from said elevator to said master frame and for effecting retraction of said printing frames back into said elevator and into their respective places.

4. A construction as set forth in claim 3 wherein: said master frame occupies an inclined position when receiving said printing frame; and wherein remote control means are provided to pivot said master frame to a horizontal printing position.

' 5. A multiple screen printing machine, comprising: a plurality of screen printing frames each having a printing screen bearing designs adapted to be brought into registry over a comto carry said printing frames in stacked relation;

a master frame over the printing area and positioned to receive printing frames from said elevator; means for shifting said elevator to bring selected printing frames into alinement with said master frame for delivery thereto; and means for effecting movement of said printing frames as selected between said elevator and said master frame; means for fixing each printing frame in said master frame so as to occupy a predetermined position common to the positions occupied by all the other printing frames in said elevator.

6. A multiple screen printing machine, comprising: a set of screen printing frame units each including an outer frame and an inner frame, a printing screen covering the inner frame, and means for adjusting and securing the inner frame relative to said outer frame, whereby when the outer frames of said set are moved in sequence into a common printing position the designs carried by the set of printing screens are caused to register; an elevator adapted to carry said printing frame units in stacked relation; a master frame positioned adjacent to'the elevator and adapted to receive printing frame units from said elevator; means for shifting said elevator to bring selected printing frame units into alinement with said master frame for delivery thereto; and means for ejecting said printing frame units as selected from said elevator to their proper place in said master frame and retract said printing frame units back to said elevator.

7. A multiple screen' printing machine, comprising: frame means providing a work piece support and an elevator support, a set of screen printing frame units in the elevator support and each including an outer frame and an inner frame, a printing screen covering the inner frame, and means for adjusting and securing the inner frame relative to said outer frame, whereby when the outer frames of said set are moved in sequence into a common printing position the designs carried thereby are in registry over a fixed area of the work piece support; an elevator in the elevator support adapted to carry said printing frame units in stacked relation; a master frame pivoted to one of the supports and positioned to receive printing frame units from said elevator; means for shifting said elevator to bring selected printing frame units into alinement with said master frame for delivery thereto; and means for ejecting said printing frame units as selected from said elevator to said master frame and retract said printing frame units back to said elevator; said set of printing frame units when stacked occupying an inclined position, and said master frame having an inclined position substantially coplanular with the unit to be fed thereto; and means for moving said master frame into a horizontal position to carry the printing frame unit therein into a printing position.

8. A multiple screen printing machine, comprising: a set of screen printing frame units each including an outer frame and an inner frame, a printing screen covering the inner frame, and means for adjusting and securing the inner frame relative to said outer frame, whereby when the outer frames of said set are moved in sequence into a common printing position the designs carried thereby are in registry; an elevator adapted to carry said printing frame units in 12 stacked relation; a master frame positioned to receive printing frame units from said elevator; means for shifting said elevator to bring selected printing frame units into alinement with said master frame for delivery thereto; and means for ejecting said printing frame units as selected from said elevator to said master frame and retract said printing frame units back to their respective positions in said elevator; and automatic ram means carriedby said master frame and cooperating with said ejector means to urge each frame unit into a common predetermined relation with said master frame.

9. A multiple screen printing machine, comprising: a set of screen printing frame units each including an outframe and an inner frame, a printing screen covering the inner frame, and

means for adjusting and securing the inner frame relative to said outer frame, whereby when the outer frames of said set are moved in sequence into a common printing position the designs carried thereby are in registry; an elevator in a housing adapted to carry said printing frame units in stacked relationship; a master frame pivoted to the housing and having a rail along each side thereof and positioned to receive printing frame units from said elevator; means for shifting said elevator to bring selected printing frame units into alinement with the rails of said master frame for delivery thereto; and means for ejecting said printing frame units as selected from said elevator to said master frame rails and retract said printing frame units back to said elevator; ram means carried by said master frame and cooperating at right angles with said ejector means to urge each frame unit into a common predetermined relation with said master frame; said set of printing frame units when stacked occupying an inclined position, and said master frame having an inclined position substantially coplanular with the unit to be fed thereto.

10. In a multi-color screen printing machine adapted to place sequentially a series of printing screens in registry over material to be printed and retract the screens therefrom, the combination of: a master frame extending over said material; a housing adjacent the master frame and having a set of screen printing frame units each including an outer frame and an inner frame, a printing screen covering the inner frame and means for adjusting and securing the inner frame relative to said outer frame, whereby when the outer frames of said set are sequentially placed in a common position the designs carried thereby are in registry; ejection means for feeding said frame units in selected sequence into said master frame; ram means carried .by said master frame for urging each frame unit therein into a predetermined relation therewith common to the other frame units of said set.

11. In a multi-color screen printing machine adapted to place a series of printing screens in registry over material to be printed and retract the screens therefrom, the combination of: a master frame having side rails extending over said material; a housing adjacent the master frame having a set of screen printing frames; a carrier for said set of screen printing frames, said carrier having vertically spaced pairs of rails disposing said printing frames in an inclined, stacked relation; protracting and retracting claw-like means for moving said printing frames in sequence between said carrier and said master frame along their rails, said master frame having an inclined, printing frame receiving position;

ceiving position shifting means carried at least in part by said master frame for urgingeach printing frame therein into a predetermined relation therewith common to the other printing frames of said set; and protracting and retracting means for moving said master frame from said inclined position to a substantially horizontal position wherein the screen printing frame therein is in printing relation with said material. a

12. In a multi-color screen printing machine adapted to place a series of printing screens in relative registry over material to be printed and retract the screens therefrom, the combination of a master frame extending over said material; a set of screen printing frame units each including an outer frame and an inner frame, a printing screen covering the inner frame, and means for adjusting and securing the inner frame relative to said outer frame, whereby when the outer frames of said set are sequentially placed in a common printing position the designs carried thereby are in registry; a carrier for said set of screen printing frame units, said carrier disposing said units in an inclined, stacked relation; means for moving said frame units in sequence between said carrier and said master frame, said master frame having an inclined, frame unit receiving position; remote controlled ram means carried by said master frame for urging each printing frame unit therein into a predetermined lateral position and thus be in a common position with the other frame units of said set when selected and positioned in the master frame; and means for moving said master frame from said inclined position to a substantially horizontal position wherein the screen printing frame unit therein is in printing relation with said material.

13. In a multi-color screen printing machine adapted to place a series of printing screens in relative registry over material to be printed and retract the screens therefrom, the combination of: a set of screen printing frames each carrying a printing screen; an elevator adapted to receive said printing frames in stacked inclined relation; a master frame; means pivotally mounting said master frame with said housing and extending at one side of said elevator to receive printing frames therefrom; means for moving said elevator in said housing to bring a selected printing frame into substantial alinement with said master frame; releasable clamping means for transferring said printing frames when alined between said elevator and said master frame; protracting and retracting means for moving said master frame between an inclined printing frame reand a horizontal position whereby the printing frame is in printing position, the pivotal axis of said master frame being disposed at one side and materially spaced from the printing frame therein whereby on raising said master frame, the printing frame screen is stripped from said material in a substantially normal direction.

14. In a screen printing machine wherein a series of printing screens are placed in sequence over material to be printed, the combination of a pivotable master frame disposed over said material; a set of screen printing frames each having a printing screen; means having a latching head for feeding and retracting said printing frames in sequence to and from said master frame; means for registering each printing frame unit into predetermined relation with said master frame; means for pivoting said master frame, said master frame having an inclined printing frame receiving position and a horizontal position placing the printing frame in printing relation to said material, the pivotal axis of said master frame being remotely displaced laterally from the material to be printed whereby in its inclined position the master frame disposes the printing frame unit well above and clear of the material, and upon movement from its printing position, printing screen strips sharply from the material beginning at its end remote from the pivotal axis of the master frame.

15. In a screen printing machine wherein a series of printing screens are placed in sequence over material to be printed the combination of: an elevator; a set of screen printing frames stacked therein in an inclined position; means for lowering said elevator in stages; means automatically operable when said elevator reaches a predetermined lower level to raise said elevator to a predetermined upper level; a pivotally mounted master frame; means for pivoting said master frame between an inclined printing frame receiving position and a horizontal position placing a printing frame therein in printing relation to said material; means for ejecting and retracting printing frames between said elevator and said master frame; and means for rendering said ejecting and retracting means inoperative to eject unless all of said printing frame units are retracted in said elevator and one of said frame units in position for ejection into said master frame.

16. In a screen printing machine wherein a series of printing screens are placed in sequence over material to be printed, the combination of: a master frame; a set of screen printing frames; a carrier therefor; means for controlling said carrier to move said screen "printing frame units in succession into position for ejection into said master frame; means for ejecting the selected printing frame unit into the master frame and holding said printing frame unit therein in a predetermined extended position; and thrust means carried by said master frame for engaging the printing frame unit therein along an axis transverse to the thrust axis of said ejector and hold the frame unit in a predetermined laterally displaced position, whereby each frame unit occupies a predetermined registry in two directions relative to the material to be printed.

17. In a screen printing machine wherein a series of printing screens are placed in sequence over material to be printed, the combination of an elevator; a set of screen printing frames stacked therein; means for moving said elevator in one direction in stages from' an initial position; automatic means for effecting return movement to its initial position; means for ejecting and retracting printing frames in sequence from and to said elevator between each stage of movement of said elevator; and means for effecting printing engagement between each ejected printing frame and material to be printed; and means for rendering said ejecting and retracting means inoperative to eject unless all of said printing frame units are retracted in said elevator and one of said frame units in position for ejection into said master frame.

18. In a device for screen printing and the like,

an elevator housing and a working surface adjacent thereto, an elevator in the housing having a plurality of parallel inclined rails spaced vertically along each side wall thereof, a shiftable printing frame on each pair of horizontally opposed rails, a master frame having side rails adapted to receive and register each printing frame with a fixed area on said surface, means pivoting the elevator housing end of the master frame and allowing the major portion of it to overhang said surface, means for automatically shifting the-elevator vertically in its housing so that any pair of horizontally opposed rails thereof can be brought into alinement with the rails on said master frame, latching means supported by the housing, keeper means arranged vertically along a side of the elevator adapted to engage the latching means at a plurality of stops along the keeper means, anyone of the stops alining a pair of rails in the elevator with the rails on the master frame, protracting and retracting means for placing any alined printing frame onto the master frame in working position and also re- 16 moving the printing frame therefrom and onto its respective pair of rails in the elevator, the correct positioning of any printing frame upon the master frame causing it to fall onto the work piece upon said surface and be ready for a printing operation.

ROBERT F. FOARD.

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

UNITED STATES PATENTS Number Name Date 15 2,206,176 Foard July 2, 1940 2,321,134 Fleisher et a]. June 8, 1943 2,338,170 Elliott Jan. 4, 1944

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