US2578779A - Feeding mechanism for printing machines - Google Patents

Description

Dec. 18, 1951 J. A. BLACK 2,573,779

FEEDING MECHANISM FOR PRINTING MACHINES Filed May 2, 1947 a 7 Sheets-Sheet 1 Dec. 18, 1951 J, BLACK FEEDING MECHANISM FOR PRINTING MACHINES 7 Sheets-Sheet 2 Filed May 2, 1947 Ja me; A. .Blacli Dec. 18, 1951 J. A. BLACK FEEDING MECHANISM FOR PRINTING MACHINES 7 Sheets-Sheet 5 Filed May 2, 1947 JUAN/14M Jllmes A.Blacls:

Dec. 18, 1951 J. A. BLACK FEEDING MECHANISM FOR PRINTING MACHINES 7 Sheets-Sheet 4 Filed May 2, 19

Jamey Dec. 18, 195 J. ,A. BLACK FEEDING MECHANISM FOR PRINTING MACHINES 7 Sheets-Sheet 5 Filed May 2, 1947 James Black Dec. 18, 1951 J, BLACK 2,578,779

FEEDING MECHANISM FOR PRINTING MACHINES Filed May 2, 1947 '7 Sheets-Sheet 6 J6me; JLBZach" Dec. 18, 1951 .J. A. BLACK 2,578,779

FEEDING MECHANISM FOR PRINTING MACHINES Filed May 2, 1947 V '7 Sheets-Sheet 7 lacli' m W j W Patented Dec. 18, 1951 UNITED FEEDING MECHANISM FOR PRINTING MACHINES James A. Black, Grand Rapids, Mich. I Application May 2, 1947,- Serial N 0. 745,411

Claims.

The present invention relates to printing machines and more particularly to machines of the silk screen stencil type by means of which pigment paints, varnishes, shellacs, adhesives and other viscous or glutinous coating materials may be forced through a silk screen stencil onto paper, cardboard, sheet metal, sheet wood, etc., for the purpose of making posters, signs, decalcomanias and the like.

The primary objects of the invention are to provide a machine of the class above indicated which is automatic in operation, having co-ordinated mechanisms whereby the stock to be coated is introduced into the machine, processed thereby, and ejected therefrom in automatic, quick succession thus to enable the processing of great quantities of stock in relatively short periods of time and with a minimum of human effort; to provide such a machine having novel feeding and ejecting mechanism whereby a unit of stock to be processed is fed into the machine in the same operation in which a processed unit of stock is ejected from the machine; to provide such a machine having novel and eflicient means for performing the silk screen operation on successive units of the work or stock being processed; to provide such a machine which is readily adjustable to accommodate stock of different sizes and different thicknesses such as relatively thin paper sheets or relatively thick plywood panels; to provide such a machine having conveniently operated means whereby frames carrying different silk screen stencils may be quickly interchanged; to provide such a machine which is so constructed that it may readily be cleaned or repaired; to provide such a machine whose moving parts may be actuated by means of fluid pres-' sure; and in general to provide such a machine which is efiicient in operation, attractive in appearance, and reasonably economical in manufacture. 1

The above objects are attained by, and the invention finds 'one embodiment in, the structure particularly described hereinafter and illustrated by the accompanying drawings, wherein:

Figure 1 is a perspective view showing the machine as viewed from above, from the left hand side, and from the rear or receiving end thereof;

Figure 2 is a topplan view of the machine illustrating display cards in three positions or stations thereon;

Figure 3 is a side elevation of the machine as viewed from the left hand side of Figure 1;

, Figure 4 is a fragmentary, central vertical sectionalview thereof taken on line 4-4 of Figure 2;

Figure 5 is an end elevation of the machine as viewed from the rear or receiving end thereof, and showing the processing mechanism of the machine in a lowered operative position in full lines and in an upwardly swung inoperative position in dotted lines; 7

Figure 6 is a horizontal sectional view taken on line 6-6 of Figure 5 and showing certain of the control mechanisms for the machine in top plan;

Figure 7 is a diagrammatic perspective view of certain parts of the machine which control the automatic feeding and ejecting means, the re-, mainder of the machine being omitted from this view for purposes of illustration;

Figure 8 is a diagrammatic perspective view of certain other parts of the machine which control the processing means, the remainder of the machine being omitted from this view for purposes of illustration; u 1 c Figure 9- is a fragmentary vertical sectional view of the machine taken on lines 997 of Figures 2 and 4;

Figure 10 is an enlarged fragmentary vertical sectional view of parts thereof, taken on line ill-40 of Figure 9; V,

Figure 11 is a fragmentary vertical sectional view of other parts thereof taken on lines I l+l IV of Figures 9 and 12, Figure 11 being on the same enlarged scale as Figure 12;

Figure 12 is an enlarged fragmentary vertical sectional view of parts of the machine taken on line I2-I2 of Figure 3;

Figure 13 is an enlarged fragmentary top plan view of parts of the processing mechanism of the machine;'

Figure 14 is a fragmentary vertical sectional view of the same, on a reduced scale, taken on line 14-44 of Figure 13 and showing certain parts of the processing mechanism in an upwardly tilted inoperative position; 4

Figure 15 is a view similar to Figure 14 an showing said parts of the processing mechanism in a lowered and operative position; and

Figure 16 is a sectional view taken on line l6-l6 of Figure 13.

Referring now in detail to these drawings wherein like parts of the structure are desig nated by the same numerals in the several views,

the various parts and mechanisms of the ma chine therein shown are mounted upon a frame generally designated 20 fabricated of angle iron lengths secured together as by welding to forma stationary structure or'frame of open box-like or rectangular parallelepiped shape the greatest dimension of which extends from side to side of the machine (see Figures 1, 3 and 5). A cradle 2| of generally square, channel iron construction, is vertically adjustably mounted on the frame 29 in a horizontal position approximately midway between the top and bottom of the frame, the lower longitudinally disposed channel iron members 22 of the cradle being secured as by welding to the tops of four vertically disposed jackscrews 23 which are mounted for vertical sliding movement in bearing brackets 25 secured to the cross.- bars 24 and located at the four corners of the square cradle 2|. Internally screw-threaded gears 26 (see Figures 5 and 6) are disposed between the upper and lower flanges of the brackets 25 and engage the jackscrews 23 respectively, and the external surfaces of the gears 26 are provided with sprockets which support a chain 28 passing around the four gears 26 and around a sprocket 29 on the lower end of a vertical shaft 30 journalled in the apex of a rearwardly convergent angle bracket 3| on the frame 20 supported by a diagonal brace 32 se cured to the outer end of the angle bracket 3| and to the lower part of the frame. A handwheel 33 is mounted on the upper end of the shaft 30, and it will be seen that turning of the handwheel will cause the chain 28 to revolve the gears 26- thus effecting raising or lowering movement of the jackscrews 23 and the cradle 2| carried thereby. Idler rolls |9 turnably mounted on the frame 20 maintain tension on the chain 28.

' The upper transversely disposed channel irons 34 of the cradle. 2| have secured to their outer ends vertically extending corner brackets. 35 of Ishaped cross-section, and each pair of corner brackets 35 at the opposite sides of the machine carries a horizontal outer section 33 of a flat work-supporting table generally designated 3?. Bolts 33 pass upwardly through the channel irons 34 and through the corner brackets 35, and are threaded in the outer table sections 36v to secure these parts in assembly. Between the outer table sections 36 are threev spaced channel bars 39 extending lengthwise of the machine and supported by the transversely disposed channel irons 3 4 of the cradle. Bolts I3 (see Figure 12) secure the channel bars 39 to the cradle 2|. The upper portions of the. channel bars 3&1 are flush with and form a part of the fiat. worksupporting table 31 and have longitudinally extending channels 43 in their upper faces, the function of which will hereinafter be described. The channelbars 33 also have laterally extending longitudinal flanges 4| thereon which are stepped below the upper surfaces .of these bars 39. The outer flanges 4| of the outermost channel bars 39 support the inneredges of the outer table sections 36, while the inner flanges 4| of the outermost channel bars 39 support the outer edges of the inner table sections 42. The flanges 4|; on opposite sides of the center channel bar 39 support the inner edges of the inner table sections 42, and thus a unitary, flat, horizontal, vertically adjustable work-supporting table. 37 having three longitudinal channels 43 therein is provided.

A stencil carrier 43 of, generally rectangular, flat metal bar construction is swingably mounted on the opposite end portions of a shaft 44 rotatably journalled in spaced bearings 45 at the upper left hand side of the machines frame 23. The stencil carrier 43 is provided with clamps 46 at the left hand side of the machine and trated in Figure 2.

4 with clamps 41 at the right hand side of the machine, which clamps 4B and 41 are adapted to detachably secure a stencil frame 48 to the carrier 43, and the stencil frame 48 which is preferably constructed of wood has a silk screen stencil 49 stretched across the underside thereof and secured thereto in any known manner as by an adhesive. It will be seen that the silk screen stencil 49 and its wooden frame 48 may readily be removed from the carrier 43 by loosening the clamps 46 and 41, and a new stencil substituted therefor according to the requirements of the work. This interchanging of stencils is facilitated by swinging the stencil carrier upwardly to its dotted line position shown in Figure 5, and after a stencil and its frame are securely clamped in position the carrier is lowered to its horizontal position shown in full lines in Figure 5 where it is maintained during operation of the machine by means of a conventional latch mechanism indicated at 53 and not shown in detail. The stencil carrier 43 is coun terbalanced to facilitate its raising and lowering movements by means of coiled tension springs 5|. attached to. the right hand corner uprights 52 of. the frame 23 and to. the lower ends of legs 53. secured to and depending from the carrier 43.

When the carrier 43 is. in its, lowered operative. position, the silk screen stencil 49 is parallel to and spaced above that. portion of the work-supporting table 3'1. which supports the work during the processing thereof, and the space between the stencil 49. and the table. 31 may be varied by turning; the handwheel 33 so that the stencil is spaced the correct distance above the upper sur face of the stock to be processed, no matter what the thickness of the stock may be. When the stencil is in itsv lowered operative. position with a unit of stock in position thereunder for processing, a print. stroke (from right to left) of a squeegee 54 across thev stencil forces coating material through the stencil and onto the stock. The details of construction and operation of the squeegee are. hereinafter fully described, butthe description immediately following pertains. tov the feeding mechanism whereby units of stock are. introduced into the machine in position for processing and ejected from the machine after processing.

.Itwill be. seen that the Work-supporting table 37, which includes the full lengths of the channel bars 33, has three distinct stations, as best illus- The station indicated by a fresh sheet of stock designated 30| is where the work is placed on the machine either manuallyor by automatic means not shown. The station indicated by a unit of stock designated 332 is where the work is processed. The station in dicated by a printed unit of stock designated 333 is where the work is removed from the machine either manually or by automatic means not shown. The mechanism by means of which the stock is advanced from station 3M to station 332 and thence after processing to station 333 comprises a set of three rails 55 longitudinally reciprooally mounted in the channels 46 of the channel bars 39. The length of the rails 55 is ap-' proximately two-thirds of the length ofthe channel bars 39, said rails having only two stations for units of the stock. It will be seen that the rails 55 are free to be reciprocated through a distance of approximately one-half their length.

Each rail 55 has a plurality of longitudinally spacedapertures 56 in its upper surface and an aeriform fluid chamber 51 therein extending the length of :the rail and communicating withithe apertures 55 (see Figures 4, 1-1 and 12). Each chamber 51 is formed by a length of square metal tubing 58 closed at its ends and having apertures 59 in registry with the apertures 55 in the rail. The tubing 58 is secured to the undersideof the rail by means of cross-pieces 60' thereunder which are fastened to the rail by means of machine screws Depending from each rail 55 slightly forwardly of the middle thereof is a hollow arm 62 with a horizontal sleeve 53 at its lower end, and the three sleeves 63 are connected by means of a pipe 64 having a flexible tube 65 coupled to oneend thereof. The other end of the tube 65 connected to one port 650i" an exhaust value B -I, and a flexible tube 68 connects the other end of the valve 51 with an'exhaust pump 69 connected to a suitable source of power such as an electric circuit (not shown). When the operating arm 15 of the valve 67 is in a rearward position opposite to its position shown in Figure I, the exhaust pump exhausts air from the tube 58, valve 61, tube 55, pipe 54, hollow arms 52 and chambers 51, thuscreating a suction at the apertures 5B of the rails 55, which suction maintains the work (stock units 31H, 302 or 353, in an adjacent pair thereof) in position on the rails thus permitting movement of the work with the rails to and away from processing position on the Work-supporting table.

The rails 55 are reciprocated in the channels 40 of the work-supporting table 31 by means of a fluid pressure operated cylinder II mounted on metal straps I2 depending from the forward ends of the channel bars 39 and having a rearwardly extending piston rod I3 connected to an arm 14 depending from the sleeve 53 of the middle rail 55. As best seen in Figure 8, fluid pressure is supplied to the cylinder II from a compressor l5 operated by a suitable source of power such as an electric current (not shown), through a tube 16, a valve Tl, andthrough one or the other of two tubes I8, 15 leading from the discharge ports 85, 8| of the valve H to the front and rear ends respectively of the cylinder II. When the operatingarm 82 of the valve 11 is in its right hand turned position shown in Figure 8, pressure is admitted through the tube I8 to the front end of the cylinder "II thus moving the rails 55 in a rearwardly direction, and when the operating arm 82 of the valve ll is in its op-, posite or left hand turned position pressure is admitted through the tube 19 to the rear end of the cylinder II thus moving the rails 55 in a forwardly direction.

The work-supporting table 3? is provided with suction apertures 83 and 88 in its upper surface similar to the apertures 56 in the rails. The apertures 33 are located in the work-processing area designated station 302 of the work-supporting table, and the apertures 55 are located in the work-feeding area designated 35! of the work-supporting table. Aeriform fluid chambers 85 (see Figures '7, 9, and in the outer and inner table sections 35 and 42 respectively, communicate with the apertures 83 and 84 and are formed by means of recesses in the undersides .of the table sections which are sealed by plates 85 secured to the bottoms of the table sections as by machine screws 81. Each plate 85 has an aperture 88 to which is coupled a depending pipe 89, and the lower ends of the three pipes all are connected by a horizontal pipe 90 which is closed at its right hand end and which has a tube 9| connecting its left hand end to the other port 92 of the exhaust valve" 51. It will be seen that when the operating arm I0 of the valve 5! is moved from its rearapertured rails 55 to the apertured work-supporting table 31.

Forward turning movement of the operatingarm 10 (see Figure '7) of the exhaust valve 61 is effected when the rails 55 reach their forwardmost position, by contact of the sleeve 63 on the left hand rail 55 with a striker arm 93 on the forward end of a slide bar 94 slidably mounted on pins 95 secured to the cradle 2! of the machine. Rearward turning movement of the exhaust valves arm II! is similarly effected by contact of said sleeve 53 with a striker arm 96 on the rearward end of the slide bar 94 when the rails 55 reach their rearwardmost position.

The squeegee 55 is mounted on the stencil carrier 43 for reciprocating movements across the silk screen stencil 49 from side to side of the machine, and these movements of the squeegee are co-ordinated with the movements of the rails 55 which feed the stock to and remove it from processing position beneath the stencil. The mountings for the squeegee 54, which is an elongated, fiat, relatively stifi bar of rubber, are best shown in Figures 13-16 inclusive. The squeegee is clamped between two metal bars designated 5'5 and 93. Arms 99 on the bar 9'! extend over the top of and downwardly behind the bar 98, so that the bar 91 is suspendedon the bar 53 with the rubber squeegee 54 therebetween (see Figure 16). Handscrews 99 are vertically threaded in arms I55 of the bar 98 which arms overhang the bar 51, and it will be seen that downward turning movement of the handscrews 99, whose lower ends bear against the top of the bar 9?, forces the bar 9'? into clamping relation with the bar 53 and with the squeegee therebetween. Vertical adjustment of the squeegee may be effected by slightly loosening the handscrews 59 and moving the squeegee upward or downward to the desired position by means of adjustment screws lIlI threaded in the bar 95 and bearing against the upper edge of the squeegee. This adjustment is best effected when the squeegee is resting against the silk screen stencil. The squeegee assembly thus formed is mounted on carriage arms I52 at opposite ends thereof by means of brackets I03 having arms I04 secured by machine screws I55 to opposite ends of the bar 98 and having arms I06 laterally adjustably and removably secured to the carriages I52 by means of knobs III! the lower ends I58 of which are threaded in the carriage arms I02. 7

The right hand ends of the carriage arms I52 are swingably journalled on a shaft IE9 extending across the stencil carrier 43 and having rollers Ill] turnably mounted on pintles III in the opposite ends of the shaft I09. The squeegee carriage comprises the shaft I59, rollers I I5, and similar rollers H2 mounted on pintles H5, the pintles III and H3 being connected by carriage plates H4. The rollers Ill] and H2 travel on lower tracks H5 which constitute the side rails of the stencil carrier 43. The free left hand ends of the carriage arms I02 are provided with rollers I16 which are adapted to travel on upper carrier 43 and which rollers squeegee carriage at its left hand end when the assume quee ee assembly is in its lowered. position hown in Fi ures. 13 and 15.. The squeegee a sembly is sprin pressed past the center ofits turnin movement to. its raised or free stroke position shown. in Figure 14, or ast center to its. lowered or print stroke position shown in Figure 15.. by. means of coiled pressure springs. II9 interposed between the carriage arms. I02 and the upper ends. of posts. I26 which are rigidly mounted on the inner ends. of the pintles. Us, The squeegee assembly is guided during these. turning movements hy pins, I.2.-I extending from lugs I22 on the carriage arms I52. through the coiled springs H and through eyes L23 in cylindrical blocks. I24 which are turnably seated in concave recesses. I25. in the upper ends of the. posts I211.

The. squeegee is. reciprocated across the screen stencil, from side to side of the machin.e,. by means of chains I26 which have their opposite ends connected to opposite ends of the carriage plates H5. and which pass under and over sprockets I2] mounted on the extreme outer ends of the shaft 44 at the left hand side of the ma.- chine, and which pass under and over sprockets I26 mounted on the extreme outer ends of a. shaft I29 journalled in bearings I36. on the opposite or right hand. end of the stencil carrier 43. Driving mechanism. for the sprockets I21: and the chains I26 carried thereby, is hereinafter more fully described.

During the operation of the machine a quantity of the coating material to be applied to the stock is stored in the stencil frame at the left hand end thereof (see Figure 14). A splatter shield I31 is secured to. the frame by the clamps 4.6. for preventing splashing of the material out of the frame. A spreader I32: is secured to the squeegee carriage for movement. therewith by means of wing screws. I33 passing through open.- ings in flanges I34. of the spreader and threaded inward projections I35 at the lower ends.

of the posts I20. The horizontal portion I36 of the spreader I32 is spaced slightly above the silk screen stencil 49, and is provided with a multiplicity of apertures I31 therein. The spreader I32 dips into the quantity of coating material whenever it reaches the left hand side of the stencil frame. During the squeegees travel from left to right across. the stencil, the squeegee assembly is turned upwardly out. of contact with the stencil as shown in Figure 14, and during this travel the spreader I32 spreads a quantity of the coating material over the stencil. This is the squeegees. free stroke. When the squeegee reaches the extreme right hand side of the stencil carrier, the rollers I I6. on the squeegee carriage arms Hi2 strike cam plates I38 mounted on the right hand side of the stencil carrier, and the squeegee is turned downwardly into contact with the stencil as shown in Figure 15. The squeegee is then reciprocated from. right to left (by means hereinafter more fully described) and makes its print stroke, forcing coating material through the. stencil onto the. unitof stock (302) therebeneath and pushing excess material ahead of it to clean the stencil. When the squeegee reaches the extreme left hand side of the stencil carrier, itis again turned upwardly out of contact with the stencil .by means: of'cam blocks I39 mounted on the upper tracks H1.

The mechanism for reciprocating the squeegee 54 and for co-ordinatingthis reciprocation with the stock feeding mechanism includes a bevel gear I40 secured on the horizontal shaft. 44 and meshing with a. bevel gear [4t secured on the. upper end of a. vertical shaft. t4! journalled in the. upper and lowerleft; hand. corners, of the frame go, A pinion I43: secured on the shaft I42 near the shafts. lower end meshes; with a. toothed sector I44. mounted at; [45 on. the. base of. the frame. 20. for turning. movement about a vertical axis. A fluid pressure cylinder: I 46.- turnably mounted. a yoke I.4.1 secured to the.

base of the frame. 2e has. a. piston rod I548; pivotally connected at. 45 to the. sector 14.4; and it will. be. seen that. reciprocation of the. piston. within the cylinder M6. eifects. reciprocation of. the squeegee 54 through the. gear train above described. This piston is. reciprocated by fluid; pressure. from the. compressor. I5 through a tube I; leading. from, the. compressor to the right hand end of a pressure. valve, I-.5t having an operating arm I52 which when in. its: forwardinmoved position. shown. in Figure. 8. admits. fluid; pressure througha. tube I53 to. the rearward end of cylinder I46. and when inits rearwardly moved: position admits fluid pressure through the tube I514. to the forward end of cylinder I145... operating arm I52 of the pressure valve I5,I is moved rearwardly from its. position. shown in Figure 8.1052 contact. of the. sleeve.- 6;3. on the. right hand rail 55. with a striker arm. t55 on. the. rearward end of a. switch bar L56. (see. Figure. 8i). slidably mounted on the frame 2.5. of the machine. The operating. arm 52 is. similarly: moved in a forwardly direction by contactof the sleeve- 63 on the right hand rail 5.5. with a strikerarm.- I'5.'I on the forwardv end of the switch bar I5.B. These movements. of the pressure. valves. openating arm IEZ'areeffectedonly when the feeding rails. 55. reach their most extreme rearward; and forward positions. and the squeegee-3s move:- ment is therefore from, left to. right when the.

= rails 55. reach their rearwardmostv position, and:

from right to left. when the .rails. reach their" forwardmost position.

The forward and rearward movements. of the; rails. 55 are initiated by the arrival. of' the sixties.-

I gee at its extreme limits. of movement. to the:

right and to the left, respectively. the squeegee reaches. the end of its movement to; the right-a depending stop I58 on the sector MA. strikes an arm I59: of; a .bell; crank lever I6l1 pivotally mounted at, I'6;I on the. base of; the. frame 20, thus moving to theleftalink I62: connects the other arm I163 of the. bell crank. lever I66 to the operating .arm 82 of the. pres. sure valve. 17;. This movement. of th arm 82 of valve 'I'I admits fluid pressure through tube,- IH to the rearward end of the pressure cylinder 1| thus moving the rails. 55. forwardly. This action is reversed when the squeegee reaches the. end of its movement to the left, whereupon the right hand end I64 of the sector I144 contacts the arm I63 of the bell crank lever IEBB- thus moving the link I62 and the arm 82- of valve 1;! to the right and admitting. fluid pressure through the tube I8 to the forward end of the pressure,

- cylinder I I and thus starting rearward movement of the rails 55.

The apertures arm the rearward portion of. the work-supporting table 31', which portion of the table is indicated asstation 391;, serve merely to hold fresh stock in correctly plaoedi positionon the table until the rails 55 carry said stock forwardly, at which time the suction through said apertures 84 is. relieved. Adjustable stops I65, I and I61 may if desired be provided to.

.5 facilitate the correct. positioning.- of stock on'the 'more any of the apertures 83 and 84 which be- ,cause of the size of the stock being run would not be covered by the stock, may be plugged by means of threaded plugs IE8 inserted in said apertures as illustrated inFigure 10, in order ;to prevent undesired intake of air through these apertures 83 and 84 during operation of the machine.

Operation With the various parts of the machine in their positions shown in Figures 2, 5, 6, '7, 8 and 14 of the drawings, the rails 55 are just completing their rearward movement and suction is on the work-supporting table to maintain in position the units of stock at stations 35H and 302 while the rails 55 pass freely thereunder, there being no suction on the rails during this phase ,of'the operation. A fresh unit of stock at station 30! has just been placed on the machine against the stops I55, I65 and IIi'I, and the unit of I stock at station 302 has just been screened by a print stroke of the squeegee 54 from right toleft. The squeegee has just been turned by the cam blocks I39 from its position shown in Figure 15 to its position shown in Figure 14. The previously printed unit of stock at station 303 is ready to be moved oif the machine. From this point on a complete cycle of the machines operation, divided into two phases, is as follows: a

. Phase I. Sleeve 63 on the left hand rail 55 strikes the striker arm 96 on the sliding bar 94, thus moving the bar 94 and the operating arm ID of the exhaust valve 61 rearwardly, and the suction created by the exhaust pump 69 is thus switched from the tube 9| and the worksupporting table 3'! to the tube 65 and the rails '55. At the same time, sleeve 63 on the right handrail 55 strikes the striker arm I55 on the switch bar I56, moving this switch bar and the operating arm I52 of the pressure valve II rearwardly. This movement of the arm I52 switches fluid pressure from the compressor I5 through the tube I55, to the tube I54 leading to the front end of cylinder I46 whose piston rod I48 is thus moved rearwardly. Sector I44 is moved by the piston rod I48 in a counterclockwise direction (about a quarter turn), and this movement of the sector I44 turns pinion I43, shaft I42 and bevel gear MI in a clockwise direction. Bevel gear I4il, shaft 44, sprockets I21 and chains I26 are thus actuated to move the squeegee 54 across the stencil from left to right for its free or non-print stroke. Upon completion of the counter-clockwise movement of the sector I44, the depending stop I58 on the sector strikes arm I59 of the bell crank lever I50, thus moving arm I 53 of said lever, link I52, and operating arm 82 of the pressure valve TI to the left. Fluid pressure from the compressor I5 through tube It is thus switched through tube is to the rearward end of cylinder II, and the piston rod I3 and rails 55 are thus moved forwardly, carrying the printed unit of stock at the processing station 3112 to the removal station 353, and at the same time carrying the fresh unit of stock at station 3! to the processing station 802.

Phase II.' When the rails 55 reach the limit of their forward .movement, sleeve 63 on the left hand rail strikes the striker arm 93 on bar 94,

thus moving bar 94 and the operating arm I0 of the exhaust valve 61 forwardly, and the suction created by the'exhaust pump 69 is thus switched from tube'65 and the rails 55 to tube 9| and the work-supporting table 31, releasing units of stock from the rails and maintaining the unit of stock now at the processing station 302 firmly in position on the work-supporting table. At the same time, sleeve 63 on the right hand rail 55 strikes the striker arm I51 on the switch bar I55 thus moving this switch bar I56 and the operating arm I52 of the pressure valve I5I forwardly, Fluid pressure from the compressor I5 through tube I50 is thus switched to tube I 53 and the rear end of cylinder I45, and the piston rod I48 is moved forwardly. Sector I44 is moved by the pistonrod I48 in a clockwise direction (about a quarter turn) thus actuating the squeegee mechanism to move the squeegee across the stencil-from right to left, and the squeegee now makes its ,print stroke forcing coating material through the stencil and onto the unit of stock now at the processing station 302. When the sector I44 completes its clockwise movement, the sector's right hand end1I64 strikes the left hand end of link I62, moving link I62 and the; operatingarm 82 of the pressure valve 11 to the right thus switching fluid pressure from the compressor I5 through tube 16, to tube I8 and the forward end of cylinder II. Rails 55 are thus again moved rearwardly and the cycle of operation is completed as the rails 55 approach their rearwardmost position.

The mechanism for effecting the movements of the rails 55 andof the-squeegee 54 has been herein shownanddescribed as being operated by compressed air from the compressor 15, but it will be understood that liquid'under pressure, or any equivalent mechanical means may be substituted for efi'ecting said movements. It will also be understood that the one specific embodiment of the invention herein shown and described contains numerous details, of construction which might be altered or omitted without departing from thespirit of-the invention as the same is defined by the claims. which follow.

I claim: p

1. In a machine of theclass described: a worksupporting table having a fiat upper surface with a work-processing positionthereon and a channel therein; a rail reciprocally disposed in the channel and having a flat upper surface flush with thatof the work-supporting table, said rail having a pair of Work-engaging stations thereon; means for reciprocating the rail relative to said processing position; mean-s associated with each of said stations for engaging a Work unit whereby movement of therail in one direction carries one station and the work unitthereon away from processing position on the, work-supporting table and carries the other station and the work unit thereon into processing position on the work- 'supporting table; said table and said rail to- 'gether forming a flat unbroken surface for supporting flat work throughout its entirety during the processing of said work.

2. In a machine ofthe class described: aworksupporting table having a flat upper surface with a work-processing position thereon and a channel therein; a rail reciprocally disposed in the channel and having a flat upper surface flush with that of the work-supporting table, said rail having a pair of workeengaging stations thereon; means for reciprocating the rail relative to saidyprocessing position; means associated with awavro each of said stations for engaging a work unit whereby movement of the rail in one direction carries one station and the work unit thereon away from processing position on the work-supporting table and carries the other station and the work unit thereon into processing position on the work-supporting table; means for disengaging both work units from the rail upon completion of said movement; and means associated with the table for engaging the work unit in processing position while the rail moves freely thereunder in its opposite direction; said table and said rail together forming a flat unbroken surface for supporting flat work throughout its entirety during the processing of said work.

3. In a machine of the class described: a work-supporting table having a flat upper surface with a work-processing position thereon and a channel therein; a rail reciprocally disposed in the channel and having a flat upper surface flush with that of the work-supporting table, said rail having a pair of work-engaging stations thereon; means for reciprocating the rail relative to said processing position; means associated with each of said stations for engaging a work unit whereby movement of the rail in one direction carries one station and the work unit thereon away from processing position on the work-supporting table and carries the other station and the work unit thereon into processing position on the work-supporting table; means for disengaging both work units from the rail upon completion of said movement; means associated with the table for engaging the work unit in processing position while the rail moves freely thereunder in its opposite direction; said table and said rail together forming a flat unbroken surface for supporting flat work throughout its entirety during the processing of said work and means for disengaging both work units from the table during movement of the rail in its first-mentioned direction.

4. In a machine of the class described: a worksupoorting member having a work-processing surface provided with a plurality of apertures and L an aeri orm fluid chamber therein communicating with said apertures; means for feeding work to said work-processing surface; and means for exhausting the aeriform fluid from said chamber to maintain by suction the work in supported position on the apertured work-processing surface during the processing thereof, the apertured work-processing surface being substantially coextensive with the work whereby the entire work is so maintained in supported position during processing. a

5. In a machine of the class described: a worksupporting table having an apertured flat upper work-processing surface and an aeriform fluid chamber communicating with said apertured surface; means for feeding flat work to said workprocessing surface; and means for exhausting the aeriform fluid from said chamber to maintain by suction the work in supported position on the apertured work-processing surface during the processing thereof, the apertured workprocessing surface being substantially co-extensive with the work whereby the entire work is so maintained in supported position during processing.

6. In a machine of the class described: a worksupporting table having an apertured flat upper surface, an aeriform fluid chamber communicating with said apertured surface, and a channel therein; a rail reciprocally disposed in the channel and having a flat upper surface flush with that of the work-supporting table; means for reciprocating the rail; means associated with the rail for engaging the work whereby the work may be moved to and away from processing position on the work-supporting table; and means for exhausting the aeriform fluid from said chamber to maintain by suction the work in position on the apertured work-supporting surface during the processing thereof.

7. In a machine of the class described: a work supporting table having an apertured flat upper surface, an aeriform fluid chamber communicating with said apertured surface, and a channel therein; a rail reciprocally disposed in the channel and having a flat upper surface flush with that of the work-supporting table; means for reciprocating the rail; means associated with the rail for engaging'the Work whereby the Work may be moved to and away from processing position on the work-supporting table; means for exhausting the aeriform fluid from said chamber to maintain by suction the work in position on the apertured work-supporting surface during the processing thereof; and means for admitting aeriform fluid to said chamber to release the work from the work-shpporting table during movement of the work away from processing position on said work-supporting table.

8. In a machine of the class described: a worksupporting table having an apertured flat upper surface, an aeriform fluid chamber communicating with said apertured surface, and a channel therein; a rail reciprocally disposedin the channel and having an apertured flat upper surface flush with that of the work-supporting table and an aeriform fluid chamber communicating with the apertured surface of said rail; means for reciprocating the rail; means for exhausting the aeriform fluid from the rails chamber to engage by suction the work with the rails apertured surface and permit movement of the work with the rail to and away from processing position on the work-supporting table; and means for exhausting the aeriform fluid from the tables chamber to maintain by suction the work in position on the apertured work-supporting surface during the processing thereof.

9. In a. machine of the class described: a worksupporting table having an apertured flat upper surface, an aeriform fluid chamber communicating with said apertured surface, and a channel therein; a rail reciprocally disposed in the channel and having an apertured .flat upper surface flush with that of the work-supporting table and an aeriform fluid chamber communicating with the apertured surface of said rail; means for reciprocating the rail; means for exhausting the aeriform fluid from the rails chamber to engage by suction the work with the rails apertured surface and permit movement of the work with the rail to and away from processing position on the work-supporting table; means for exhausting the aeriform fluid from the tables chamber to maintain by suction the work in position on the apertured work-supporting surface during the processing thereof; and means for admitting aeriform fluid to the tables chamber to release the work fromv the Work-supporting table during movement of the work away from processing position on said work-supporting table.

10. In a machine of the class described: a work-supporting table having an apertured fiat upper surface, an aeriform fluid chamber communicating with said apertured surface, and a channel therein; a rail reciprocally disposed in the channel and having an apertured flat upper surface flush with that of the work-supporting table, an aeriform fluid chamber communicating with the apertured surface of said rail, and a pair of work-engaging stations on said apertured surface of said rail; means for reciprocating the rail; means for exhausting the aeriform fluid from the rails chamber to engage by suction a work unit with each of said stations whereby movement of the rail in one direction carries one station and the work unit thereon away from processing position on the work-supporting table and the other station and the work unit thereon into processing position on the work-supporting table; means for admitting aeriform fluid to the tables chamber to release the Work from the work-supporting table during said movement of the rail in said one direction; means for exhausting the aeriform fluid from the tables chamber to maintain by suction the work in position on the apertured work-supporting surface during the processing thereof; and means for admitting aeriform fluid to the rails chamber to release both work units from said rail during the processing of the work unit in position therefor while the rail moves freely thereunder in its opposite direction.

JAMES A. BLACK.

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

UNITED STATES PATENTS Number Name Date 1,235,499 Peters July 31, 1917 1,343,648 Smith June 15, 1920 1,832,828 Borregard Nov. 17, 1931 1,901,473 Respass Mar. 14, 1933 1,922,710 Owens Aug. 15, 1933 2,019,721 Nejedly Nov. 5, 1935 2,039,909 Kem May 5, 1936 2,183,293 Leach Dec. 12, 1939 2,229,346 Shurley Jan. 21, 1941 2,253,534 Rundell Aug. 26, 1941 2,339,268 Huffman Jan. 18, 1944 2,352,983 Trump July 4, 1944 2,421,210 Louft May 27, 1947 2,425,210 Stokes Aug. 5, 1947 FOREIGN PATENTS Number Country Date 535,360 Germany Oct. 9, 1931

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