US2555096A

US2555096A - Silk screen printing machine

Info

Publication number: US2555096A
Application number: US711510A
Authority: US
Inventors: George W Reinke
Original assignee: ROTO SCREEN Co
Current assignee: ROTO SCREEN Co; ROTO-SCREEN Co
Priority date: 1946-11-22
Filing date: 1946-11-22
Publication date: 1951-05-29
Anticipated expiration: 1968-05-29

Description

May 29, 1951 G. w. REINKE sILx scREEN PRINTING MACHINE 13 Sheets-Sheet 1 Filed Nov. 22, 1946 |||||||||I l||||l I1 11.. .A -.-Il

| l l l May 29, 1951 G, w, RElNKE 2,555,096

SILK SCREEN PRINTINGMACHINE Filed Nov. 22, 194e 1s sheets-sheet 2 @www Ms.

May 29, 1951 G. w. REINK SILK SCREEN PRINTING MACHINE Filed NOV. 22, 1946 15 Sheets-Sheet 5 INVENTOR.

13 y@ WM E @Mayi G. w. REINKE SILK SCREEN PRINTING MACHINE May 29, 1951 15 Sheets-Sheet 4 Filed NOV. 22, 1946 May 29, 1951 G. w. REINKE SILK scREEN PRINTING MACHINE 13 Sheets-Sheet 5 Filed Nov. 22, 1946 INVENTOR. 660739@ WcL'IZ@ May 29, 1951 G. w. 'REINKE 2,555,096

SILK scREEN PRINTING MACHINE Filed Nov. 22, 1946 15 Sheets-Sheet 6 1N TOR. 6607396' WRE/Z/rc May 29, 1951 G. w. REINKE y SILK scREEN PRINTING MACHINE 13 Sheets-Sheet 7 INVENTOR. f GcmkgcVl/Reme IIIIIIII Filed Nov. 22, 1946 IIIIIIIIIIIIIII rial- I I I I I I IIIIII I I I l I I I I l I I I Ma 29, 1951 G. w. REINKE 2,555,096

SILK SCREEN PRINTING MACHINE Filed Nov. 22, 194e 155 sheets-sheet s mi |||||||.l

May 29, 1951 G. REINKE SILK SCREEN PRINTING MACHINE 13 Sheets-Sheet 9 Filed Nov. 22, 1946 May 29, 1951 G. w. REINKE SILK SCREEN PRINTING MACHINE 15 sheets-shee't 1o Filed Nov. 22, 1946 LILI.

INVENToR. GCOTgcJ/IRCZ'lZ/c May 29, 1951 G. w. REINKE 2,555,096

SILK SCREEN PRINTING MACHINE Filed Nov. 22, 1946 l 13 Sheets-Sheet 1l "f 29, 1951 G. w. REINKE 2,555,096

SILK SCREEN PRINTING MACHINE Filed NOV. 22, 1946 13 Sheets-Sheet l2 May 29, 1951 Filed Nov. 22, 1946 9 IF might 7@ z G. W. REINKE SILK SCREEN PRINTING MACHINE 115 Sheets-Sheet 13 1N VEN TOR.

Patented May 29, 1951 SILK SCREEN PRINTING MACHINE George W. Reinke, Park Ridge, Ill., assignor to Roto-Screen Company, Chicago, Ill., a corporation of Illinois Application November 22, 1946, Serial No. 711,510

(Cl. lOl-424) 11 Claims. l

This invention relates in general to printing machines and particularly to a silk screen printing machine having novel features to produce a ne quality of reproduction.

There have been a number of attempts in the past to produce a satisfactory silk screen printing machine, but numerous difficulties have arisen. For example, properly registering the paper for feeding to the screen has presented a serious problem with the result that earlier machines have been unable to perform as fine a quality of work' as that which could be 0btained by the hand printing process. Therefore, when fine quality work was necessary, such as that comparable to a lithographie process, the hand printing was resorted to.

These earlier machines presented other difficulties such as the proper coordination of the various parts, and the screen itself was so located that it could not be easily reached for cleaning both sides thereof.

All of the various disadvantages presented by earlier screen printing machines have been overcome in the invention disclosed herein, and numerous other advantages have resulted therefrom. It is, therefore, one of the principal objects of the present invention to provide a silk screen printing machine which will produce a fine quality of work comparable to that of a lithographic process in full four color process reproduction and which will reproduce up to approximately 133 lines half-tone.

Another object is to provide a machine of the character herein described with novel sheet feeding registering means whereby full four color reproduction may be obtained comparable to that of a lithographic process.

A further object is to provide a novel drive mechanism for a silk screen printing machine for properly coordinating the various steps in the printing process and which will permit proper and accurate registering of the paper.

. Still another object is to provide a novel inking fountain arrangement whereby proper ink distribution is obtained in properly timed relation with movement of the screen.

A still further object is to provide novel operating and adjusting mechanism for the squeegee bar whereby multi-color printing may take place and the amount of ink forced through the screen thereby may be controlled.

Another and more specific object of the invention is to provide a novel mounting and actuating means for the screen to facilitate cleaning both sides thereof. The manner of' mounting and the adjustability of the screen also being such that the screen fra-me may be moved for proper registration instead of the register pins, thus permitting paper to be fed to the same point at all times.

Other objects and advantages of the invention will become apparent upon reading the following description taken in connection with the accompanying drawings in which:

Fig. 1 is a side elevational view of the machine;

Fig. 2 is a rear end elevational View;

Fig. 3 is an enlarged sectional View taken substantially along the plane of line 3--3 of Figs. 1 and 4;

Fig. 4 is an enlarged vertical longitudinal sectional View through a part of the machine taken substantially along the plane of line 4 4 of Fig. 3 and showing the screen in its uppermost position;

Fig. 5 is a sectional view similar to Fig. 4, but showing the screen in its lowermost position;

Fig. 6 is a view similar to Figs. 4 and 5 but showing the parts in a still different position;

Fig. 7 is a side elevational view partly in section of the inking fountain and the ink feed bar;

Fig. 8 is a fragmentary front elevational view of that part of the device shown in Fig. 7;

Fig. 9 is a transverse sectional view taken substantialy along the plane of line 9 9 of Fig. 5;

Fig. 10 is a front end elevational view partly in section and taken substantially along the plane of line D-i of Fig. 11;

Fig. l1 is an enlarged fragmentary side elevational view with certain parts removed to show details and taken substantially along the plane of line Il-ll of Fig. 3;

Fig. l2 is a fragmentary longitudinal sectional View taken substantially along the plane of line 42-12 of Fig. 10;

Fig. 13 is a detailed end elevational View of the drive mechanism taken substantially along the plane of line 'I3- i3 of Fig. l;

Fig. 14 is a plan view of the drive mechanism shown in Fig. 13;

Fig. 15 is a vertical sectional view of the drive mechanism taken substantially along the plane of line l5--l5 0f Fig. 13;

Fig. 16 is a fragmentary plan View of the printing drum and sheet gripper assembly;

Fig. 17 is a plan View of the screen and screen frame with parts broken away to show details;

Fig. 18 is fragmentary transverse sectional view taken substantially along the plane of line iS-IS of Fig. 17 and including in addition the rack guide;

Fig. 19 is a fragmentary side elevational view of the scilneen frame shown in Fig. 17;

Fig. 20 is a fragmentary sectional view of the screen frame taken substantially along the plane of line Ml-2Q of Fig. 17; and

Fig. 21 is a fragmentary sectional View taken substantially along the plane of line 2i-2I of Fig. 20.

The silk screen printing machine disclosed herein comprises in general a main frame on which the various operating mechanism is adapted to be mounted. The silk screen through which the printing is done is located angularly for ease in cleaning and is mounted for reciprocation in suitable guides. Although the angle at which the screen is mounted may vary withinY wideY limits, the preferred angle which has obtained satisfactory results in actual practice is approxi'- mately 35 with respect to the horizontal. A squeegee for forcing the ink through. the screen is suitably mounted adjacent one side thereof and mechanism is provided for withdrawing the squeegee from the screen during its non-printing stroke and for pressing the. squeegee against the screen during the printing stroke thereof. An adjustment is provided for the squeegee whereby the amount of ink. forced through the screen may be properly controlled'.

Novel drive mechanism is mounted a-t one end of. the mainY supporting frame for properly driving and coordinating the various steps of the printing process. As stated above, one. of the great objections and disadvantagesv of earlier printing machines of this character has been the inability to. properly register the paper so as to obtain a ne quality of work comparable to that of a lithographie process. The drive mechanism of the present invention is such as to permiteJ proper register of the paper against grippers which carry the paper around a cylinder and against the screen, such grippers being gradually retarded in their rotary movement toward a sheet to be fed. thereto and being stopped in their rotary movement momentarily at the time of gripping the paper to enable the paper to thus 'be placed thereagainst and provide a proper register therefor.

The various advantages of the present invention and the specific mechanism which has been designed to attain the objects enumerated, will become evident upon a more detailed description of the machine. To facilitate an understanding of the construction and operationof the machine, the description thereof has been .divided into separate headings as follows:

. The drive mechanism The screen reciprocating mechanism The inking fountain The squeegee operating and adjusting mechanism . The sheet feeding and delivery mechanism The operation of the machine The machine may be embodied in. and. supportedV by a suitable main frame which, in the illustrated. form of the invention, may include a pair of spaced supporting frame members l located at the bottom of the machine and the upwardly extending

supportingV members

2 and 3 at the front and: rear ends of the machine respectively. The feed table 4 is located at the front of the machine for the purpose of feeding sheets of paper to the printing mechanism, and may be supported by spaced upwardly and angularly extending members 5 secured at the lower ends to the supporting members I. Vertically extending spaced angle members .V adjacent the rear of the machine are adapted to support a part of the drive mechanism and may have additional angularly disposed supporting members 'I at the upper part of the machine to thereby provide a sturdy construction. Horizontally disposed spaced apart angle members 8 are located near the upper part of the machine to which various actuating means may be mounted, and angularly disposed guide members 9 are 'positioned at each side of. the frame to. support the screen frame for reciprocation.

The driving mechanism For the sake of clarity, the end of the machine where thev feeding of the paper takes place for the printing operation will be referred to as the front' end of the machine, and the rear end thereof will be that end where the printed sheet is` delivered. The motive power which actuates thedriving mechanism is preferably located at the rear end of the machine and comprises a suitableA support Hl on which. an electric motor ll may be mounted. The motor Il is provided with a suitable shaft I2 to which is secured. a pulley I3 adapted to drive a pulley It mounted on the shaft I5 (see Fig. 2) by means such as the belt` i6.

The shaft t5 is suitably mounted at each end thereof in the bearings Il' and I8, this latter bearing being mounted. on. the upwardly extending supporting member I9 which is in turn secured to the. transversely extending angle member 2U forming a part of the main frame.

Any desirable means may be provided for connecting. the main drive shaft l5 to the driving mechanism so that the connection therebetween may be released to stop further operation of the machine. This may be done by a suitable clutch mechanism including a manually operated lever arm 2l secured to a shaft 22 which has a small arm 23 also secured thereto so that actuation. of the arm 2i will rotate the shaft and induce a rotary motion of. the, arm 23. This. latter arm is provided with a link 24 pivotally secured at its other end to an upwardly extending arm 25 by means of. the. pivot, pin 2B. The arm 25. is bifurcated at its upper end to provide a yoke 2l and is pivotally mounted to the supporting member I3 i-n such a way that actuation of the` arm 2| will move the yoke 22'!v toward the right or toward the leftas viewed in Fig. 2 for actuating the clutch mechanism.

The upper end of the arm 25 is suitably connected to a clutch mechanism 28 tov thereby releasably connect the shaft l5 to the shaft 29. This latter shaft is connected to a speed reducer 3D of any' suitable and well known construction whereby the shaft 3| thereof will rotate at a reduced speed.

The shaft 3l has mounted thereon the large gear 32 adapted to be in mesh with a smaller gear 33 on the shaft 35:1 which also has secured thereto the small operating pinion 35 adapted to actuate thedrive mechanism for reciprocatingV the screen frame and properly coordinating the gripper fingers of the sheet delivery mechanism.

Figs. 13, 14 and 15 illustrate the preferred form of driving mechanism and the operation thereof will be made more clear by reference to these figures where the mechanism is shown apart from the other details of the machine as in Fig. 2. rlhe end of the shaft 34 is adapted to be mounted in a roller bearing 36 as shown in Fig.. 15. They drive mechanism includes avertically reciprocating frame comprising the upper and lower bars 3l' and t3. A rack frame 39 is adapted to be so mounted on these bars 3'! and 33 so as to permit not only a vertical reciprocation of the rack frame, but also a reciprocating movement from side to side on these bars. The construction is such that the bars are stationary during side to side reciprocation of the rack frame 39 thereon, but will be carried with the rack frame during vertical reciprocation thereof.

Upper and lower supporting

bars

49 and 4| may be welded or otherwise secured to the rack frame 39 and are adapted to support the bearings for the rack frame to be mounted on the

transverse bars

31 and 39. The mounting means of the upper bar 4D includes a pair of spaced members 42 secured to one end thereof and adapted to support spaced apart roller bearings 43 and 44, one on each edge of the bar 31. The other end of the supporting bar 40 also has secured thereto a pair of similar members 45 having roller bearings 45 and 41 located therebetween also in contact with the upper and lower edges of the bar 41. The lower supporting bar 4| is similarly constructed by being provided at one end thereof with the supporting members 48 having the

roller bearings

49 and 59 secured thereto and at its other end the members 5l with the

roller bearings

52 and 53 thereon.

The bar 31 at the upper part of the frame is adapted to be received betweenthe

upper rollers

43 and 46 and the lower rollers 44 and 41. Likewise, the lower bar 38 of the frame is received between the

upper rollers

49 and 52 and the

lower rollers

50 and 53. It will thus be evident from this construction that when the rack frame 39 is caused to reciprocate vertically, it will carry with it the upper and

lower bars

31 and 38. It will also be clear that the rollers mentioned above provide a bearing surface to permit the rack '1 frame 39 to be moved from side to side on the

bars

31 and 38.

The rack frame 39 has mounted at one side thereof a rack 54 which is adapted to be in mesh at all times with the pinion 35 mounted on the shaft 34. The rack 54 is composed of spaced vertically extending

rack members

55 and 56 at 'each side thereof and with horizontally extending

rack portions

51 and 59 at the upper and lower ends thereof respectively. The upper and lower rack portions join with the

side rack portions

55 and 55 to thus provide a continuous rack of substantially a rectangular shape with rounded corners which will be in mesh at all times with the pinion 35. Since the shaft 34 and pinion 35 mounted thereon are secured to a stationary part of the main frame, a rotation of the pinion 35 will cause a movement of the rack frame 39 in both a horizontal and vertical direction. As the frame moves in a horizontal plane, it will remain stationary with respect to any vertical movement, and during the vertical reciprocation thereof no movement will occur in a horizontal plane except' during the period of movement when the pinion 35 is in mesh with the rounded corners of the rack.

This movement of the rack frame 39 and the

bars

31 and 39 on which it is mounted may be more easily understood by viewing Fig. 14. Here it will be noted that the two horizontally eX- tending

bars

31 and 38 are connected at their ends by means of a vertically extending flange 59 at each end thereof. Each flange 59 is provided with a roller 59 extending in one direction and other rollers 5l positioned at right angles thereto. A guide bar 52 extends vertically adjacent each of the ila-nges 59 and has a centrally located elongated groove therein adapted to receive the rollers 6I. The rollers 65 are adapted to bear against that portion of each guide 62 located adjacent the central groove therein.

The manner in which the drive mechanism just described actuates the various parts of the ma"- chine to coordinate the various steps of the printf"- ing operation will become more apparent upon a descriptionof each of the mechanisms separately. For the present it Will be suicient to understand that operation of the motor l I, when the clutch 29 is engaged, will rotate the shaft 34 and the pinion 35 in mesh with the teeth on the rack 54. In the position of the rack shown in Figs. 2 and 13, if the pinion 35 is rotating in a clockwise direction, the rack and its frame 39 will be moving toward the left and the

horizontal bars

31 and 38 Will remain stationary until the rounded corners of the rack are reached at which time the entire frame will begin to move upwardly. This upward movement continues until the bottom of the rack portion 55 is reached at which time the frame and its connected parts will reach its uppermost position. There will then be a dwell or pause in the vertical movement of the frame while it is moving back toward the right and until the pinion 35 reaches the rack portion 55, at which time the frame will be moved downwardly. This action occurs during operation of the machine continuously and will act to reciprocate the screen frame, will properly apply the ink to the screen and will actuate the grippers at the proper moment while they remain stationary during the above referred to dwell. During this dwell, the grippers will be opened by mechanism to be described hereinafter at which time the paper may be moved thereagainst in proper register and then moved against the screen for the printing step.

The screen reciprocating mechanism In describing the screen and its connection with the rack frame 39 whereby the screen is caused to reciprocate on the main frame, reference will be particularly made to Figs. l, 3, 4, 5, 6, '1 and 8. A rack 63 is positioned vertically at each side of the moving frame and is secured as by welding or other suitable means to the upper and lower horizontally extending cross bars 31 and 38. Thus, as the

bars

31 and 38 are reciprocated in a vertical plane by movement of the rack frame 39, the vertically extending racks 93 will also be caused to reciprocate vertically. A gear 54 is mounted at each side of the main frame and is adapted to rotate freely on the shaft 55. These gears 64 have a rotary reciprocating motion which is transmitted thereto by being in mesh with the racks 53. As these racks reciprocate vertically,

va rotary reciprocation of the gears 64 Will oca reciprocation of the screen and screen frarne in an angular direction, as more clearly seen in Figs. 4, 5 and 6. A counter-balancing spring 59 is suitably secured to each of the gears `54 at one end thereof and to a stationary part of the main frame at the other end thereof to aid in the operation of the various reciprocating parts whereby less power is necessary to operate the machine.

The novel construction of the screen frame whereby the screen may be adjustably mounted therein may be more clearly understood by reference to Figs. 1'7 through 21 inclusive. Here it will be seen that the screen frame at each side thereof is provided with a side member l@ to which the upper rack 68 is secured along one edge thereof and a lower rack 'il is secured adjacent the bottom edge thereof. The screen frame is adapted lto ride in guide members consisting of spaced guide bars 'I2 and 'I3 secured to the inner side of the angularly extending side frame members 9. The two guide bars 'l2 and 'I3 being mounted in spaced relation will thus provide an elongated groove lll. The frame itself has a pair of rollers l5 mounted on the underside of the rack 68 and a second pair of rollers 'i6 suitably mounted adjacent the lower rack which extend within the space 'ifi to provide support for the screen frame during reciprocation thereof. The rollers l5 at each side of the screen frame are adapted to ride on the guide bars '|2, maintaining perfect sidewise alignment, and the rollers 'I'G are mounted at substantially right angles with respect thereto and ride on the guide bars 13.

The screen itself is mounted on an angle iron frame 'il on which may be mounted iloating wooden frame members extending along the four sides of the screen. The lower angle member 'I8 is adapted to rest on a second angle member la which has secured thereto a pair of clamping members 80. Each clamping member is provided with a screw threaded clamp 8| so that as the screen frame is inserted at the lower end thereof between the angle member 'I9 and the clamping members 89, the members 8| may be utilized to clamp the screen in place.

A novel feature of this machine is the provision of a iine adjustment for the screen within the screen frame whereby the position of the screen therein may be adjusted for purposes of proper registry. When the screen is thus adjusted, it will permit a sheet of paper to be fed into the machine at the same point each time. It never becomes necessary to change the position of any gauge pins or other registering devices against which the edge of a sheet of paper being fed into the machine is to be placed. The adjustable feature of the screen and its frame is more clearly illustrated in Figs. 17, and 21 where it will be noted that the upper horizontal edge of the screen frame is provided with an inner angle member 82 and an outer angle member 83. rlhese angle members are so positioned relative to each other that one leg of each member is in contact with each other and the other legs thereof extend upwardly in substantial parallelism. rlhe upwardly extending leg of the angle member 83 is provided with a T-slot 84 adapted to receive the threaded end of an adjusting nut 85. The threaded end thereof is received by a threaded opening in a block 86 secured to the angle member 82. The

other leg of the angle member 83 has a slot 8l therein adapted to receive a clamping nut 88l which extends through the opening 8l and is secured to the angle member 82. Thus it will be evident that by screwing the adjusting member 85 in one direction or the other, a corresponding move- -ment of the angle bar 82 will be effected. As may screen is in proper registry, the clamps 8| and 88 may be tightened and the screen will be ready for the printing operation.

When the rack frame 39 is caused to recprocate vertically carrying with it the racks B3, the two gears 64 in mesh therewith will have a rotary reciprocating movement. Likewise, the screen and screen frame within which it is mounted, having suitable racks 68 also in mesh with the gears 64, will be caused to reciprocate in an angular direction through the guide bars 'l2 and 13. A novel inking fountain and means for distributing the ink over the screen in preparation for the printing operation is located at the lower end of the screen frame and will now be described.

The inking fountain The lower end of the screen frame is provided with a forwardly and upwardly extending ink retaining member 89 as may be seen in Figs. 4, '7 and 8, whereby a fountain is provided extending the width of the screen at the lower end thereof within which a quantity of ink 90 may be provided at all times and may be moving with the screen during the reciprocation thereof.

The ink is caused to be distributed over a portion of the screen at the lower side thereof by means of a movable framework consisting of an upper transversely extending rod 9| having a roller 92 at each side thereof adapted to be rolled against the upper guide bars l2 as the screen moves upwardly. A lower transversely extending rod 93 is connected with the rod 9| by means of the connecting bars Sil at each end thereof. Each of the racks 68 has an extension 95 at the upper end thereof adapted to have secured thereto a carrying member 96 which may take any suitable form and, in the illustrated embodiment of the invention, may comprise merely a block of metal. A stop member 91 is adapted to be welded or otherwise suitably secured to the side frame members 8 and 9 at the juncture thereof and against which the rollers 92 will bear to support the rods 9| and 93 after the screen frame has moved downwardly a suflicient distance.

ln the operation of the ink distributor, when the screen frame moves upwardly, the lower rod 93 will be immersed in the ink 90 as shown in Fig. 4. The frame consisting of the rods 9| and 93 will be carried upwardly by the carrier members 96 for the full distance of the screen movement, but on the downward movement thereof, the rollers 92 will come against the stop members 9? and withdraw the lower rod 93 from the ink 98 as the screen continues to move downwardly, at which time the relative position of these parts will be like that shown in Fig. '7. As the rod is withdrawn from the ink, it will carry with it a quantity of the ink and distribute it over the lower part of the frame. On the next upward movement of the screen, the ink thus distributed will be carried with the screen, but as it moves downwardly again the ink will be picked up by the squeegee and forced through the open interstices of the screen and transferred to a sheet of paper on the opposite side thereof for printing. The printing operation and the construction of the squeegee will now be described.

The squeeyee operating and adjusting mechanism Reference will now be made more particularly to Figs. 3, 4, 5, 6 and 9 where the flexible squeegee is indicated by the numeral 98. The squeegee is suitably mounted on a bar 99 extending transversely of the screen and screen frame and may be of any suitable length. That is to say, if the printing impression is to take place throughout the entire width of the screen, then the squeegee and its mounting bar 9d may extend the full width thereof. On the other hand, if the subject matter to be printed is to consume a relatively small or narrow area on the screen, then the squeegee and its supporting bar may be of a width just sufficient to cover the printing area. This type of construction is also advantageous for simultaneous multi-color printing whereby the inking fountain may be provided with partitions with a different colored ink in each section thereof and a plurality of squeegees may be mounted so that each will print with a different colored ink.

One or more of the squeegee bars 99 may be clamped in place on a mounting member which extends throughout the width of the screen. Any suitable clamping or mounting means can be utilized for securing the squeegee in place, and the illustrated form includes a clamping member IOI having a block |02 adapted to be placed against the bar or mounting means |00 and a second smaller block |03 adapted to bear against the squeegee bar 99. Suitable bolts may then be inserted through the member IDI and the blocks |02 and |03 to thereby clamp the squeegee bar 09 in place. This construction is clearly illustrated in Figs. 4, and 6.

It is necessary that the squeegee 98 be held forcibly against the screen during the printing operation to transfer the ink therethrough to the paper on the opposite side thereof. It is equally necessary that the squeegee be removed from the screen during the non-printing reciprocating movement thereof. To accomplish this result I have provided novel mechanism for pressing the squeegee against the screen during the downward movement thereof and for elevating the squeegee away from the screen during the upward movement thereof. This mechanism comprises a plate |04 at each side of the screen frame to which the supporting member |00 is secured. Each plate |04 is mounted on an extension |05 of a bar |00 which extends downwardly at each side of the machine and is mounted for a rotary. movement on the transversely extending shaft |01 suitably mounted in bearings |08. The bearf ings |08 are located on a transversely extending stationary angle member |00 of the main frame to which the counter-balancing spring 09 may also be secured as shown. The upper ends of the extensions |05 are secured together by means of the transversely extending bar H0.

An adjusting bar I|| is also located at each side of the machine and is mounted for pivotal movement on the bars |00 by suitable pivot pins II2. The upper end of each adjusting bar I II is bifurcated as indicated at |I3 and is adapted to be received within the sides of a U-shaped bracket II4 mounted on the connecting bar I|0. An adjusting screw I I5 threadedly engages each of the brackets I|4 whereby it may extend between the sides thereof, each screw I I5 being provided with an annular groove IIB adjacent its inner end to receive the bifurcated end ||3 of the bar III. This construction admits of a suitable adjustment to be made with respect to the pressure of the squeegee 98 against the screen during the printing operation. This adjustment may become necessary because of different circumstances such, yfor example, as where the viscosity of the ink may vary thus requiring more or less pressure to force it through the interstices of the screen.

The actuating means for raising and lowering the squeegee is secured directly to each of the adjusting bars III and moves the squeegee the same distance upon each operation thereof. Thus the force with which the squeegee bears against the screen will depend upon the initial location of the adjusting bars |I| with respect thereto. If the adjusting screws II5 are moved outwardljr from the brackets H4, the bars III will be elevated so that when the actuating mechanism moves the squeegee against the screen, it will bear against it with a lesser force. Likewise, if a greater force is desired, then the adjusting screws II5 may be moved inwardly whereby the adjusting bars I I I will be closer to the screen.

Additional clamping means in the form of a member I at each side of the machine and secured to the cross bar I I is provided which has an elongated clamping bolt ||8 threadedly secured thereto. The outer end of this bolt is adapted to bear against the clamping means |0I for the squeegee supporting bar whereby the entire structure is securely held in place.

The actuating means for moving the squeegee toward and away from the printing screen con--l sists of a slide member |I9 at each side of the machine having an elongated recess |20 therein adapted to receive the shaft 65. One end of the slide II9 is secured to the adjusting bar III as at |2| whereby a reciprocating movement of the slide member II9 will carry with it the bar III and the squeegee connected thereto through the means described above. The sliding movement of the slide member takes place about the shaft 65.

A shaft or rod |22 extends transversely of the machine and is secured at each end thereof to a slide member II9. Two other transversely extending rods |23 and |24 are also mounted on the slide members II9 at the opposite end thereof. The rod |22 has a cam follower |25 rotatably mounted at each end thereof and similar cam followers |20 are located at each end of the rod |23.

while the cam followers |21 are mounted at each end of the rod |24. An actuating cam |28 is secured to the shaft 05 at each end thereof by any suitable means such as the clamping member |29 whereby the cam will be rotated continuously in the same direction with the shaft 65. The means by which this shaft rotates will be explained hereinafter.

Between the ends of the shaft and the various rods above mentioned, a limiting bracket is located which is provided with spaced side members |30 adapted to embrace the shaft 65 and which has at one end thereof a spacer member |3I and at its other end a slotted bracket |32. The rod |22 is adapted to be received by the slot in the member |32 and limits the reciprocating movement of the slide member I I9.

The shaft 65 is mounted in suitable bearings |33 and |34 secured to the supporting side frame members 8 of the main frame. One end of the shaft 65 has a bevel gear |35 secured thereto and is adapted to be in mesh with another bevel gear |30 mounted on the shaft |37 which extends along one sideof the machine from the front to the rear thereof. At the rear end of the machine, the shaft |31 is mounted for rotation in a bearing |38 and has a toothed wheel |39 secured thereto adjacent the rear end. A chain drive |40 is in engagement with the toothed Wheel |39 and also engages a small toothed wheel |4| on the y; shaft 3|. The chain then passes over an idler 1 I wheel |42 and as the shaft 3| is the driving shaft emanating from the speed reducer, it Will thus' drive the shaft |31 by means of the chain |49. Obviously, rotation of the shaft |31 and the bevel gear |36 thereon in mesh with the bevel gear |35 will rotate the shaft 65 to which is secured the cams |28. In the position of the cam |28 as shown in Fig. 4, the edge thereof Vis bearing downwardly against the rollers of the slide member I9. When this occurs, the slide member and the parts connected thereto, including the adjusting bars the bars ||J6 and the squeegee 9B will also be moved downwardly so that the squeegee will exert a pressure against the printing screen. This driving means is so synchronized with respect to the reciprocating movement of the screen and screen frame as to actuate the squeegee 98 toward and against the screen as the screen moves downwardly. When the screen reaches its lowermost position, or before such time if so desired, the cam |28 will be rotated to its position shown in Fig. 5 where the edge thereof bears against the rollers i2? and elevates the slide members ||9 together with the Squeegee connected thereto. As the cam continues to rotate, the edge thereof will also contact the rollers |26 to maintain the squeegee in its elevated position during the upward movement of the screen.

` As explained above, during the upward stroke of the screen, the lower cross member 93 of the inking frame will be immersed in the ink 90, so that as the screen moves downwardly to its lowermost position, the inking frame will distribute a quantity of ink across the bottom portion of the screen. The ink will thus remain in this position until the screen again reaches its uppermost position, at which time the cam |28 is operated to press the squeegee against the screen and the ink which has been distributed thereon, so that such ink will be forced through the screen and onto a sheet of paper at the opposite side thereof for the printing operation as the screen moves downwardly.

The sheet feeding and delivery mechanism The sheet of paper to be printed may either be fed by hand to the machine or any suitable form of automatic sheet feeding means may be used. In the illustrated form of the invention, no automatic sheet feeding. means have been disclosed, but the manner in which the sheet is gripped and rolled against the screen for printing will be the sameeven though the sheets are fed by hand. The sheets may be manually placed on the feeding table 4 and fed to a drum |44 located beneath the screen and which has a gear at each side thereof mountedv for rotation on the transversely extending shaft |46. These various parts may be more clearly understood by viewing Figs. 3, 4, 5, 10, 12 and 16.

These gears |45 are adapted to be in mesh with the racks on the underside of the screen frame so that as the screen reciprocates, the drum will also have a rotary reciprocating movement. The drum is provided with an lopening |41 extending substantially throughout the length thereof against one edge of which suitable gripper fingers may be actuated to grasp the edge of a sheet of paper being fed thereto and roll it against the screen. A number of strengthening webs or spacers |48 may also be disposed in spaced relation throughout the length of the drum if so desired.

. The gripper finger assembly comprises a supporting bar |49 extending substantially the length of the drum and mounted along one edge of the opening |47. A plurality of gripper fingers |55 are adapted to be reciprocated in such a way that when they are in closed position, they will bear against an edge of the supporting bar |49 and when in open position they will be adapted to receive the edge of a sheet of paper. Each gripper |50 has an inwardly extending tail piece |5| slidably mounted within a blocl; on the supporting bar |49. The tail piece |5| has a projection |53 thereon against which a rotary recipro- :ating actuator |54 is adapted to bear for actuating the gripper linger |5 and moving it to its open position to receive a sheet of paper. The actuator |54 is suitably secured on the rock shaft |55 whereupon a rocking of the shaft in one direction will urge the gripper outwardly away from the drum and a movement in the opposite direction will permit the coiled tension spring |56 secured thereto to draw the gripper inwardly by reason of the connection of the other end of the spring toa rod |57 extending lengthwise of the drum. Any suitable number of gripper assemblies may be located in spaced relation on the supporting bar |49 and along the shaft I 55 so that a sufficient number may grasp the edge of a sheet and roll the sheet against the underside of the screen in its downwardly movement.

Suitable mechanism is provided for rocking the shaft |55 each time the drum |44 reaches the end of its rotary reciprocating movement in both directions. Fig. 4 shows one of the grippers in its closed position for gripping the edge of a sheet of paper for printing and Fig. 12 shows the gripper in its open position with the shaft |55 rotated a suflcient amount for the actuating member |54 to move the gripper |59 outwardly. It is just as necessary to open the grippers at or before the end of their rotary reciprocating movement in the opposite direction so that the printed sheet may be delivered from the machine. The actuating mechanism for rocking the shaft |55 may be more clearly understood by reference to Figs. 10 and 11 where it will be noted that the rock shaft |55 is mounted for rotation with the drum |44 and extends beyond the drum whereby a cross member |58 may be keyed thereto. This cross member |58 rotatably supports the cam followers |59 and |59 at each end thereof. A suitably mounted cam |61 is so located that when the rotation of the drum is in a counterclockwise direction and the grippers thereof are in the position shown in Figs. 4 and 12, the cam |6| will be in a position relative to the cam roller |59 as shown in Fig. l1. At this moment, suitable mechanism to be described hereinafter, will elevate the cam |6| against the cam follower |59 which will thus impart a rocking movement of the shaft |55 in a clockwise direction. By reference to Figs. 4 and 12, it will be obvious that such a rocking of the shaft |55 will cause the gripper fingers |50 tobe moved to open position in readiness for receiving the edge of a sheet of paper. l

A second cam |62 is mounted on an vupwardly extending support |63 secured to the horizontal stationary support |64 at the opposite side of the drum |44, whereby, when the drum is vrotated in a clockwise direction, the cam roller will come against the undercurved side of the cam |62 and again rotate the rock shaft |55 in a clockwise direction to open the gripper fingers |50 'and permit the printed sheet being heid thereby to lbe delivered from the machine.

The shaft las supporting the drum V44 is' suit- 13 ably mounted iny bearings |55 also located on and secured to the horizontally extending stationary frame member |84.

When paper is fed to the machine along the table 4, it is necessary that adjustable side guide members be provided to compensate for differentv widths of paper even though the machine has been designed to permit a feeding of the paper to the same point at all times. One form which the side guide or stop member may take is illustrated in Fig. 3 where the stop member |58 is shown as being secured to a slidably mounted bar I9? mounted for a sliding movement within the guide members |63 and |59. The outer end of the bar may be provided with a plurality of spaced apart openings |10 adapted to receive a pin |1'I extending between the sides of the guide |89. in this way, the pin |1| may be removed and the bar |91 together with the stop member |59 thereon may be moved in either direction to a location suitable for the size of the sheet of paper being fed, and the pin then replaced in a suitable opening |19 which will hold the side stop in its proper position. It will be evident that any other suitable form of side stop as well as securing or clamping means therefor may be used if so desired.

As the paper is being fed to the grippers |50 it is desirable that a plurality of guide fingers be provided for guiding the edge of the sheet downwardly and to prevent the edge from curling upwardly. To this end a transversely extending supporting bar |12 spaced upwardly from the table 4 is provided which has a plurality of guide fingers |19 curved downwardly and extending toward the drum. The fingers |13 terminate short of the position of the gripper lingers |50 in sheet receiving position so that no interference with the operation of the grippers will result.

A plurality of movable gauge or register pins are also provided to enable the operator of the machine to initially position the paper properly for feeding to the grippers. As the operator feeds the sheet toward the drum, the forward edge thereof will iirst come against a plurality of these pins for a preliminary positioning of the sheet. When the gripper fingers open and are in readiness to receive the sheet, then the pins move upwardly. The cylinder gripper fingers then slightly bump against the sheet assuring registration on the cylinder itself. To the attainment of this end, a transversely extending pin supporting bar |14. is provided having a plurality of spaced apart gauge pins extending downwardly therefrom and positioned closely adjacent the drum |44. Each end of the bar |14 is rounded so that it may be rotatably mounted within a supporting member |15 located at each side of the machine. The bar |14 is caused to rock by means of an extension |11 secured to one end thereof, which extension is adapted to be received between the legs of a U-shaped bracket |18 (see Fig. 10). Suitable securing means are provided to fasten the end of the member |11 within this bracket and, as will be presently pointed out, a vertical reciprocation of the bracket |18 will carry the end of the member |11 with it and thus cause a rocking movement of the bar |14 to raise and lower the gauge pins |15.

14 screw |83 may be adjusted upwardly or downwardly to adjust the downward movement of the bar 180 and its connected parts since it bears against the upper end of the bracket |8| in its lowermost position.

Referring again to Fig. 1l, it will be clear that the lower end of the reciprocating bar is pivotally connected to a link |84 having a slot |85 in its outer end adapted to receive a suitable pin |86 for purposes of guiding the movement of the link. The cam l6| above referred to as actuating the rock shaft |55, is mounted on the link |84 and is movable therewith. It will thus be clear that an upward movement of the reciprocating bar |80 will perform two functions, one of which is to carry with it the bracket |11 for rocking the bar |14 in a clockwise direction for operating the gauge pins |15, and the other of which is to elevate the cam |6| to rock the shaft |55 also in a clockwise direction to open the gripper ngers |50.

When the lower part of the cam |89 is reached, the various parts will drop downwardly by gravity which will actuate the gauge pins |15 and the gripper fingers |50 in the opposite direction. The drive means for rotating the shaft |31 have been described above and the cam |89 is so positioned thereon as to actuate these various parts in timed relation so as to grasp the sheet and roll it against the underside of the screen in properly timed relation with the reciprocation thereof.

A delivery mechanism for delivering the printed sheet from the machine is also provided. It will be understood that any suitable form of mechanism may be utilized for this purpose, the means disclosed herein being merely for purposes of illustration. The delivery means disclosed may be more readily understood by reference to Figs. l2 and 16 where a gripper device generally indicated at |92 is mounted on a chain driving means |93 located at each side of the machine and immediately below the drum |44. The chain |93 is driven by means of a toothed wheel |94 mounted at each end of a transversely extending shaft |95 at the forward end of the machine and another toothed wheel |96 at each side of the machine located rearwardly thereof. The shaft |95 is mounted for rotation in suitable bearings |91 1ocated at the forward end of the main supporting frame and the toothed wheels |96 are mounted for rotation on a transversely extending shaft |98 which has a bevel gear |99 mounted at one end thereof.

The chains |93 and the gripper devices |92 are caused to move continuously in a counter-clockwise direction as indicated in Fig. l2 by means of a bevel gear 200 in mesh with the bevel gear |99, which gear 200 is mounted on a rearwardly extending shaft 20| `iournaled in bearings 202 and 203 mounted at the front and rear ends of the frame respectively.

Referring momentarily .to Fig. 2 it will be ap-