US2796831A - Printing screen registering device - Google Patents

Description

June 25, 1957 P. L. HEESTAND 2,796,831

PRINTING SCREEN REGISTERING DEVICE Filed 001:. 12, 1954 2 Sheets-Sheet 1 iiiiiiii m 1mm CF V 1/ r; 3 1 L A I-\ llli i 1 l5 5 J {4 {7 47 I INVENTOR PGII/ZL HGGStG/II/J BY fi ATTORNEYS June 25, 1957 P. L. HEESTAND PRINTING SCREEN REGISTERING DEVICE 2 Sheets-Sheet 2 Filed Oct. 12. 1954 INVENTOR- Pau/l L.Heesia md 0E ATTORNEYS 'I ite are This invention relates to apparatus for use in the method of printing known as the silk screen process, and more particularly to a device for registering a printing screen on a table or bed plate for repeatedly printing a pattern in exactly the same registered position on successive sheets of paper or the like.

In the silk screen printing process a stencil is used comprising a pattern on a screen which is stretched across a rectangular frame. In the usual hand-operated apparatus, the screen is mounted on hinges attached to the top of the printing table. A sheet of paper to be imprinted is placed upon the table top and the hinged screen is swung down upon it with the screen in contact with the paper. link is then placed on top of the screen and forced through the screen by a squeegee. The screen is then lifted about its hinges, the sheet of paper removed and the operation is repeated on successive sheets. Each sheet may be printed in several colors, each color requiring a separate screen stencil and a separate printing operation.

One of the problems which must-be solved in screen printing is to obtain exact registration so that each sheet will be printed in exactly the same areas. Exact registration is especially important where a plurality of impressions are to be made upon each sheet, as in printing a plurality of colors. The stencil pattern must be in exact registry not only in its position lengthwise of the printing table and transversely of it, but it must be oriented correctly, that is, it must be twisted at the correct angle with respect to the sides of the table. Screen printing frames vary considerably in size. For the foregoing reasons, it is necessary to make adjustments every time a printing frame is changed so as to have the screen registered correctly with respect to the position of the sheets for the next run. In practice, this requires frequent shifting of clamps and spacers. Often the position of the hinges must be changed. These adjustments are awkward to make and are timeconsuming with conventional equipment.

One of the objects of this invention is to provide improved apparatus for screen process printing. Another object is to provide improved means for handling a wide variety of sizes of screen printing frames. Another object is to provide apparatus in which a screen may be quickly clamped onto a hinged mount or holder and the frame then moved universally on the table, while the screen remains parallel to and adjacent the printing surface of the table, to a desired register position and clamped firmly in this position for the printing operation. Other objects will become apparent from the following description and drawings in which:

Figure 1 is a view in perspective showing a preferred embodiment of my invention viewed from the front meunted on the top of a printing table or bed plate and holding a screen printing frame in registered position.

Figure 2 is a view in perspective of the same embodiment removed from the table and viewed from the rear.

Figure 3 is a fragmentary view in section taken along line 33 of Figure 1, portions of the bed plate and screen printing frame being indicated in broken lines.

2,796,831 Patented June 25, 1957 Figure 4-is-afragmentary view in section taken along line 4-4 of Figure 1.

Figure S- is a fragmentary view in section taken along line 5-5 of Figure 1.

Figure 6 isa view in section taken along line 6-6 of Figure 5.

Referring now to the drawing, in which like characters indicate similar parts, there is shown a screen printing frame registering device according to my invention, generally designated 10, comprising a clampable cross bar 11, ahinged mounting bar designated 12, and adjustable links 13-13 connecting bar 11 and bar 12. Figure 1 shows the device mounted on a printing table or bed plate 14 which preferably has metal edge-reinforcing strips 15-15, one on eachside. At each end cross bar 11 has a short portion bent at right angles to embrace the edges of table 14 as shown in Figure 5. By means of a clamp designated 17, comprising a turnbolt 17a threaded in one downturned end of bar 11 and a swiveled pad 17b bearing against one of the strips 15, bar 11 may be clamped in a desired position along the length of the table top or bed plate. Strips 15 thus coactwith clamp 17 and the bent end portions of bar 11 in the clamping action. Threadedly mounted in bar 11, as at 18a in Figure 3, area pair of turnbolt clamps 18-48. As indicated in Figure 3, the shankor pin portions 18b of these turnbolts extend freely throughelongated slots 13aof links 13. When clamps 18 are slightly unscrewed, links 13 are free to slide and rotate with respect to the'portions 18b of turnbolts 18. When clamps 18-are screwed down tightly against washers 18c, links 13 are held securely in position with respect to bar 11.

At'the front end of each link 13, as best shown in Figure 3, there isan aperture 19a through which a pin 19 extends. Each pin 19 is threadedly secured in a hinge leaf 20 as indicated at 1%. The heads of pins 19 do not bind links 13 against hinge leaves 20, links 13 and leaves 7 20 being free to swing relative to each other about pins 19 when clamps 18 are released. Hinge leaves 2tl20 are hingedly mounted upon bar 12 by hinge pins 2121 which have a common axis. It will be observed that the separate hinge leaves 20-20 may be joined by a bar or the like if desired without changing the essential character or oper ation ofthe device, but the illustrated arrangement minimizes interference with the novel screen clamping means 22 described below.

As will be seen from the foregoing description and drawing, bar 11 may be clamped in selected position on the top of printing table or bed plate 14 by means of clamp 17. With clamps 18 loosened, so that links 13 are free to slide and rotate with respect to pins 18b, screen mounting bar 12 may be moved universally parallel to the plane of the top or printing surface of the bed plate 14 to a desired position in registry for the printing operation. In this position mounting bar 12 may be pivotally moved about hinge axis 2121 so as to raise and lower the screen frame. As best seen in Figures 3 and 4, hinged mounting bar 12 has a flat surface 12a which is vertically disposed when the bar is in the downward or printing position illustrated in Figures 3 and 4. On the back of bar 12 are a plurality of bosses 1211 with apertures extendingthrough the bar 12 from front to back as best seen at in Figure 4. The plurality of apertured bosses 12b provide means for attachment suitable screen clamping means such as is illustrated and generally designated '22. In the illustrated embodiment, only one such clamp 22 is shown utilizing only the two central apertured bosses 12b. However, a longer clamp may-be used extending the full length of mount 12 and utilizing the bosses 12b at each end, or two clamps of the same size as illustrated at 22 may be used, each using a pair of clamps adjacent one end of bar 12.-

As best shown in Figure 4, clamp 22 comprises a jaw 22a fixedly secured as by welding to theends of two threaded bolts 22b whichextend through apertures 12c. A nut 220 on the threaded outer end ofeach bolt 22b provide means for drawing jaw 22a toward surface 12a of bar 12. Strips 22d are provided along thelower inner edge of jaw 22a. A screen frame 23 maybe clamped between the surface 12a of mounting bar 12 and jaw 22a of clamp 22. Jaw 22a is a comparatively thin plate and it constitutes a stiff spring jaw. Also, as clearly shown in Figures 3 and 4, the lower portion of jaw 22a when relaxed is inclined slightly inwardly toward clamping surface 12a. In Figure 3 a fragmentary part of a screen frame is indicated in broken lines as being lightly engaged by strips 22d, with plate 22a in relaxed position. Although other forms of movable clamping jaws may of course be used, this combination of spring jaw 22a with its strips 22d coacting with fixed jaw surface 12a has been found very effective for a quick clamping of screen frames. It will be observed that mounting bar 12 and screen frame clamp 22 combine to form a screen frame mount 12-22 which is hingedly mounted to the remainder of the device by hinge means 20-20 and 21-21.

In operation, a screen printing frame is clamped to mounting bar 12 by clamp 22 in the manner described. With clamp 17 released and clamps 18 tightened bar 11 is then moved along the surface of the bed plate 14 to bring the screen frame 23 into approximate position for printing. Clamp 17 is then clamped and clamp members 18-18 loosened. Frame 23 is then moved into exact registry position, the slotted links 13 and pins 19 permitting universal movement of the frame 23 in a plane parallel to the top of bed plate 14. Turnbolts 18 are then tightened. This firmly fixes hinge leaves 20-20 with respect to the bed plate 14 and registers the frame 23 and mount 12-22 in the desired position. By means or marks not shown each successive sheet to be imprinted is registered on bed plate 14. Mount 12-22, carrying frame 23, is rotated abouthinge pins 21-21 for the printing operation, always returning to the exact registered position when lowered.

It will be apparent to those skilled in the art that I have provided an improved printing screen registering device which is of simple and rugged construction, which is well adapted for quick and accurate adjustment to any desired registry position of the screen, and which can quickly accommodate different screen frames which vary widely in size.

Although only one embodiment of my invention has been described, various other embodiments within the spirit of the invention as defined by the appended claims will be apparent to those skilled in the art.- As examples, and without limitation, other suitable adjustable linkage may be used between bed plate 14 and hinge means 20-20. Bar 11 may be eliminated and turnbolts 18 threadedly mounted in suitable sockets fixed in bed plate 14, the slotted links in this case being somewhat longer to provide for adequate adjustment of the device lengthwise of bed plate 14. As another example, other frame clamping means may be substituted for the illustrated clamping means 22. p

I claim as my invention:

1. In combination with a'pfri'nting table having a printing surface and parallel longitudinal edges, a movable cross bar clampable to said table, spaced upstanding pins mounted on said cross bar, an adjustable link for each of said pins connected respectively thereto for sliding thereon and rotating thereabout parallel to said printing surface, register clamping means for clamping each of said links in selected fixed position on said cross bar, a screen frame mount having means for clamping a screen frame thereto, hinge means attached to said mount having hinge leaves mounted on a hinge axis parallel to said printing surface, and spaced pivots perpendicular to said printing surface one for each of said adjustable links each pivotally connecting one end of its adjustable link with one of said hinge leaves, whereby a screen frame may be clamped to said screen frame mount, moved universally parallel to the printing surface, and said mount clamped in a selected position on said table free for rotation about said hinge axis.

2. In combination with a printing table having a printing surface and parallel longitudinal edges, a hinged printing screen holding and registering device comprising a movable cross bar on said table extending across said longitudinal edges, position clamping means for clamping said cross bar in selected position on said table, spaced upstanding pins mounted on said cross bar, a slotted link for each of said pins each having a longitudinal slot slidably surrounding its respective pin for sliding thereon and rotating thereabout parallel to said printing surface, register clamping means for clamping each of said links in selected fixed position on said cross bar, vertical pivots one for each of said adjustable links and each mounted adjacent an end of a different one of said adjustable links, hinge leaves one for each of said vertical pivots and mounted respectively thereon for free movement thereabout, a screenframe mounting bar hingedly mounted on said hinge leaves by aligned hinge pins having a hinge axis parallel to said printing surface, said mounting bar having a surface opposite said hinge leaves for engaging the outer surface of one side of a screen frame to be clamped, and a frame clamp having a jaw for engaging the inner surface of said side of a screen frame to be clamped, rods fixed to said jaw extending through said frame mounting bar and frame clamping means for drawing said rods through said mounting bar to clamp said screen frame to said mounting bar, whereby a screen printing frame may be clamped to said screen frame mounting bar, said position clamping means and said register-clamping means loosened, said screen frame moved to 'selected' position along the surface of said printing table and oriented at a selected angle relative to said longitudinal edges, said position and register clamping means tightened, and said screen printing frame raised and lowered from and to the selected register position.

3. A hinged printing screen registering device for registering a printing screen in selected position on a bed plate and maintaining it securely in said position during hinged printing operations, comprising a screen mount, screen frame clamping means for detachably clamping a screen frame to said mount, a pair of laterally spaced hinges on said mount for swinging said screen frame about a hinge axis parallel to said bed plate, each said hinge having a leaf with a pivot perpendicular to said bed plate, a link for each said pivot pivotally' attached at one end to said respective pivot, and a pair of laterally spaced means slidably and swingably engaging said respective links supported by said bed plate for immovably securing said links independently in predetermined positions, whereby a screen frame may be clamped to said screen frame mount, moved universally parallel to said bed plate, and said mount clamped in a selected position on said table free for rotation about said hinge axis.

References Cited in the file of this patent UNITED STATES PATENTS 1,533,700 Dibble et al Apr. 14, 1925 FOREIGN PATENTS 7 495,071 Germany Apr. 2, 1930 647,097 Great Britain Dec. 6, 1950 1,064,791 France Dec. 30, 1953

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