US 2975705 A
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March 21, 1961 lLMA SILK SCREEN PROCESS PRESS Filed Feb. 12, 1958 4 Sheets-Sheet 1 INVENTOR. L 0 0/5 6/ LM A N BY 52 EK/EL WOLF HIS ATTORNEY March 21, 1961 G|LMAN SILK SCREEN PROCESS PRESS 4 Sheets-Sheet 2 Filed Feb. 12, 1958 INVENTOR. L 00/5 G/LMA/V BY ZE/(/L M/OLF H/S A TTORNEY March 21, 1961 GlLMAN SILK SCREEN PROCESS PRESS 4 Sheets-Sheet 3 Filed Feb. 12, 1958 March 21, 1961 G|LMAN 2,975,705
SILK SCREEN PROCESS PRESS Filed Feb. 12, 1958 4 Shets-Sheet 4 f ii E a I i:
I! \J k H R H I H U R 1 i: Q1 1'' W I N t- INVENTOR. LOU/S G/LMAN BY ZEK/EL WOLF HIS ATTORNEY SILK SCREEN PROCESS PRESS Louis Gilman, Newtonville, Mass. (80 Hampshire St., Boston 20, Mass.)
Filed Feb. 12, 1958, Ser. No. 714,728
7 Claims. c1.101--1zs) The present invention relates to an improved press particularly designed for silk screen process reproduction.
In silk processing it is extremely important to apply the squeegee against the silk screen with uniform pressure over the entire stroke. It is also important to coat the screen evenly with paint before the squeegee makes its run.
The present invention sults' in a simplified and inexpensive press.
The present invention further provides a silk screen process press designed to permit close registration in which the squeegee contacts the screen while moving in one direction only, while an even coat of paint on the screen is assured by the spreading action of a filler bar which moves across the screen when the squeegee is returned to its initial printing position.
The present invention also provides a structure in which the squeegee pressure remains constant during the entire printing stroke. This feature is obtained by forming the frame in which the squeegee is journalled for reciprocal' movement with an angular section at initial printing end of the stroke. This angular section carries the squeegee away from the screen when the screen is placed and locked in the printing position. Upon the actuation of the printing stroke, the squeegee is brought gradually into contact with the screen just prior to the printing stroke so that a substantial pressure may be built up between the squeegee and screen before the printing stroke commences, which pressure is maintained during the entire stroke.
Further, the present invention provides an operating mechanism including cam controlled cycling means which cooperate with the angular section of the frame to pro vide a rigid, interlock of the screen, frame and printed material before the printing stroke commences but inv such a manner as to permit a gradual increase of pressure designedto obtain these re- 2,975,705. Pat ented Mar. 21, 1961 therethrough (not shown) at the other side of which may be connected means (also not shown) for providing air suction through the holesso that any paper positioned on the table top will be rigidly secured in place. On the top surface 10 of the inverted U-shaped supporting beam 3 is a gear box 11 having a driving shaft 12 and two preferably coaxial driven shafts f3 and 14 which are operably responsive to rotation of shaft 12 with shafts 13 and 14 rotating uniformly with respect to one another and in the same direction. The driving shaft 12 is operatively connected to a drive mechanism (not shown) such as a constant speed motor through a suitablearrangement of the squeegee upon the screen just prior to the printing stroke.
' These and other objects and advantages of the present invention will be more clearly understood when considered in connection with the accompanying drawings in which Figure 1 is a side plan view of the invention with the screen in an open position;
Figure 2 is a side plan view of the invention with the screen in a closed position, and the squeegee in position before its printing stroke; V
Figure 3 is a side plan view of the invention with the squeegee in an intermediate printing positionjand Figure 4 is an end plan view of the invention taken from the left of Figure 2. j a
In this arrangement there is provided a suitable supporting frame which may comprise a series of structural angle members welded or otherwise suitably secured to- I gether to form a supporting base for a table top 1. This such as a belt and pulley arrangement including a pulley as indicated at 15.
There is mounted on driven shaft 13 a cam 17 designed to engage the rollerltl which in turn is pivotally supported to the lever arm 19 intermediate its ends. -The lever arm 19 forms part of a lever linkage system Which-is operatively engaged to the channel frame 20 for the purpose of raising and lowering this channel frame 20 to and from a printing position, the channel frame also carrying with it the silk screen, squeegee, and filler bar. The channel frame 20 'is mounted on a pair of parallel supporting arms 21' toward'its rear end 9. These supporting arms 21 extend normally from opposite sides of the channel frame 2d, and are rigidly secured by welding or other suitable means at their lower ends to a shaft 22 which extends parallel to the plane of the frame 20. As the arms 21, shaft 22 and frame 28 are all rigidly connected, rotation of the shaft 22 will cause a pivoting movement of the frame toward and away from the table top 1. The ends of the shaft 22 are suitably journalled in journal blocks 23, in turn secured to the base of the press preferably on a level with the top 1. Also, rigidly secured at one end to the shaft 22 is a lever arm 24 which also forms a portion of the aforementioned lever linkage system. An intermediate lever 25 is pivotally interconnected at one end 26 to the other end of lever 24 and at the other end 27 to the other end of lever 19. These levers 19 25 and 24 are so proportioned that when the frame 20 is in down position as illustrated in Figure 2, the levers l9 and 25 will be longitudinally aligned with the lever 24 substantially normal to the aligned levers 19 and 25. In this position, the channel frame 2i) is substantially locked in position, for in order for it to pivot to an open position it would have to work through the lever 24 against a theoretical infinite resistance of the levers 19 and 25, unless these'levers 19 and 25 are pivoted to a non aligned position at the end 27. These levers 19, 25 and 24 are normally tensioned to this locked position by the weight of the frame 20. The levers however are cyclically moved from this position by the rotation of the cam 17 which, as indicated, engages the roller 18, thus providing a reciprocal pivotal movement of the frame 2i Operating synchronously with the lever linkage system and frame 20 is the squeegee operating mechanism and filler bar arrangement generally indicated at 30. This mechanism which Will be more fully described hereinafter reciprocates between the ends of the frame as through the operation of the mechanism generally indicated at 31. This mechanism 31 includes an elongated lever arm 32, pivotally secured at its lower end 33 to the member 34, in turn secured to the end-of beam 3. The upper end of the lever arm 32 is pivotally interengaged with the lever arm 35 at 36. The lever arm 35 in turn pivotally engages and operates the squeegee and filler bar mechanism through a pivotal connection 37. Intermediate the ends of the lever arm 32 is pivotally connected the end of an operating lever 38, which also pivotally engages at its other end the operating lever 39. The lever 39 is pivotally mounted at its other end on beam 3 in a suitable journal indicated at 40. Intermediate the ends of the lever arm 39 is a roller 41. The roller 41 engages the cam 42 (Figure 2) with the cam in turn pivotally mounted on the shaft 14. The roller 41 is normally maintained in contact with the cam 42 through the tension of spring 43 whiclris suitably connected at one end to the lever 32 and at the other end to the frame preferably at the forward end, as indicated at 45.
Referring now to the channel frame 20, it will be observed that it is formed preferably U-shape with parallel side members 50 and 51 and an end member 53. Side members 50 and 51 (see Figure 4) provide inwardly facing channels within which the carriage 56 may reciprocally move. Particular attention is directed toward end portion 90 of the channel frame. It will be noted that this end portion 90 is formed slightly angularly to the plane of the rear portion of the channel frame. This provides means, as will be more fully referred to hereafter, of moving the carriage angularly away from the screen and table top as it is moved forwardly toward the end 7 of the press. This carriage 56 comprises a pair of transversely extending axles 57 having wheels or bearings 58 mounted at each end thereof and adapted to slide back and forth within the channels. A pair of side members 59 on either side of the frame interconnect the forward and rear axles 57. Also forming a portion of each side member is a downwardly extending angle member 60 which is rigidly interconnected with the side member 59. A shaft 61 extends between the opposite downwardly extending members 60 and has pivotally mounted on it a support 62 to which a pair of parallel extensions 63 are rigidly secured. An adjusting screw 64 extends upwardly through each extension 63 and threads into the carriage in such a manner as to permit the pivotal movement of the extension 63 toward and away from the plane of the side members 59 by the expedient of adjusting the screws 64. At the forward end of the extension 63 there is provided a downwardly turned end 66 which carries with it the squeegee 67. This squeegee 67 comprises preferably a supporting block, as indicated at 69, with a resilient wiping member 70 extending longitudinally of and fitting within the block 69.
The lever 35, as indicated, is pivotally interconnected at end 37 to the carriage mechanism. The short lever arm 71 is pivotally interconnected at 37 at its upper end and at its lower end to the shaft 61. Extending angularly forward from and rigidly connected to the lever 71 intermediate its ends 37 and 61 is an operating arm 72. The forward end of this operating arm 72 pivotally supports an operating rod 73 at '74. The lower end of the operating rod 73 loosely engages the loop 75 in turn rigidly connected to the filler bar 76. This filler bar 76 is slidably mounted, as for example by a sleeve 78 attached to the tiller bar 76, on parallel rods 77 which are secured at their upper ends to the sides 59 by suitable means.
The lower edges of the squeegee 67 is adapted to engage the upper surface of a silk screen secured to the bottom of the screen frame 80 during the printing stroke. This screen frame 80 is preferably rectangular in shape and is formed of four side members enclosing an open center under which the screen is secured. One end, 81, is pivotally secured by the hinge member 82 to the table top parallel to and just in front of the shaft 22. The other end of the frame 80 is loosely interengaged with the forward end of the channel frame 20. This engagement is effected by a hook 84 secured at its lower end to the upper surface of the frame and a hook 85 secured at its upper end to extension 86 in turn secured to the forward side of the channel frame. The hooks 84 and 85 are loosely interengaged by a ring 87. Thus, as the frame 20 is raised, it will carry' with it frame 80 as illustrated in Figure 1, while still permitting the pivoting of the two members on separate axes.
As previously indicated the end portion 90 is formed slightly angularly to the plane of the rear portion of the channel frame. Thus, as the carriage 56 moves to a forward position as the frame 20 is moving downward to its locked position as illustrated in Figure 2, the squeegee 67 at the foremost position will be raised away from the table top 1 and will consequently be out of pressure contact with the screen mounted on the frame 80. As the printing stroke progresses the carriage 56 moves rearwardly toward end 9, carrying with it the squeegee 67 which is spring loaded relative to the carriage by spring 64. Thus, as the carriage is brought down into parallel alignment with the table top as the carriage moves toward the rear portion of the frame, the squeegee 67 will contact the screen and table top with substantial pressure determined by the adjustment of the screws coaxial with the springs 64. This substantial pressure will be uniformly maintained during the entire printing stroke. It will be noted, however, that the pressure was not built up until after the levers 19 and 25 were positioned in their locking positions (see particularly Figure 2).
When the squeegee has completely traversed the printing area of the screen, the earns 17 and 42, which are synchronized, cause the raising of the frame 20 and the screen which is attached to it in the manner as illustrated in Figure 1. While these members are raised the squeegee and filter bar are returned to the initial printing position. During this return action, however, the squeegee 67 is spaced from the screen while the filter bar is in contact with it (see Figure 1). This is due to a forward motion of the lever arm 35 which is translated into a downward pressure on the filler bar 76. At the end of the cycle when the squeegee has reached its initial printing position, the cam has returned the frame 20 and screen to the position as indicated in Figure 2.
Having now described my invention, I claim:
' 1. In a screen process press having a screen, a table top, means mounting said screen for pivotal movement against said top, a squeegee and means mounting said squeegee for movement into positive pressure contact across said screen, the combination comprising channels at least substantially as long as said screen within which said means mounting said squeegee is mounted, means for pivoting said channels into fixed parallel relation above said screen, end channel portions continuous with said channels extending angularly away from said screen when said channels are in said fixed position with said channel portions adapted to receive said squeegee mounting means at the beginning of said movement of said squeegee, and means for rigidly securing said channels and channel portions in said position before the movement of said squeegee whereby said squeegee will be guided by said channel portions and channels into a gradual positive pressure contact with said screen during its movement and after said channel portions are secured in said position.
2. In a screen process press having a screen, a table top, means mounting said screen for pivotal movement against said top, a squeegee and guide means for guiding said squeegee for movement in positive pressure contact across said screen, the combination comprising means for securing said guide means and screen in fixed relation, and means for moving said squeegee across said screen, said guide means including channels having portions parallel to said screen and end portions diverging therefrom with said squeegee guided by said portions whereby means are provided for gradually building up the pressure contact between said squeegee and screen after said mounting means and screen are secured in fixed relation.
3.In a screen process press having a screen, a table top, means mounting said screen for pivotal movement against said top, a squeegee and guiding means for guiding said squeegee for movement into positive pressure contact across said screen, the combination comprising means for securing said guiding means and screen in fixed relation, means for moving said squeegee across said screen, said guiding means comprising a frame having an angular section adapted to guide said squeegee with one portion adapted to be secured parallel to said screen for maintaining uniform positive pressure between said squeegee and screen along said portion and a second port-ion diverging om said screen adapted to provide an initial gradual increase in pressure contact between said screen and squeegee.
4. A device as set forth in claim 3 wherein said means for securing said guiding means comprises a lever linkage system adapted also to pivot said guiding means to and from parallel alignment with said top, said system having a pair of longitudinally aligned levers providing an infinite resistance against pivotal movement of said securing means when said securing means is parallel with said top.
5. A device as set forth in claim 3 wherein said means for securing said guiding means comprises a lever linkage system having a pair of interengaged levers fixed at one end and pivotally engaging at the other an extension of said guiding means, said levers adapted to be longitudinally aligned when said guiding means are parallel to the top thereby presenting an infinite resistance to movement of said guiding means, and a cam engaging said levers for movement thereof to and from said aligned position,
6. A device as set forth in claim 5 providing a second cam and means for operating said cams in synchronism, said second cam operatively engaging said means for moving said squeegee.
7. A silk screen process press comprising a frame, a horizontally disposed work receiving surface secured to said frame, a silk screen, a rectangular frame mounting said screen, means for pivoting said screen about one edge into facing relation with said surface, an elongated squeegee guide means having opposed parallel elongated channel portions at least substantially as long as said screen and having continuous angular end portions, means pivotally mounting said elongated channel portions at,
one end for pivotal movement to and from a parallel position with respect to said facing relation position of said screen, with said end portions. gradually diverging therefrom, an elongated squeegee, means mounting said squeegee between said parallel portions for slideable movement therealong, means for sliding said last mentioned means from said end portion along said channel portions whereby said squeegee may be guided by said end channel portions into a gradual positive pressure contact with said screen, and means for rigidly securing said channel portions and screen in fixed relation before actuation of said last mentioned means.
References Cited in the file of this patent UNITED STATES PATENTS 1,843,116 Aldcroftt et a1. Feb. 2, 1932 2,229,346 Shurley Jan. 21, 1941 2,321,134 Fleisher et a1. June 8, 1943 2,581,775 Wade Jan. 8, 1952 2,588,878 Reemelin Mar. 11, 1952 2,704,510 Walsh Mar. 22, 1955 2,894,451 Landesman July 14, 1959