US2881700A

US2881700A - Silk screen printing machine

Info

Publication number: US2881700A
Application number: US644255A
Authority: US
Inventors: Joseph E Podgor
Original assignee: Individual
Current assignee: Individual
Priority date: 1957-03-06
Filing date: 1957-03-06
Publication date: 1959-04-14
Anticipated expiration: 1976-04-14

Description

April 14, 1959 J. E. PODGOR SILK SCREEN PRINTING MACHINE Filed March 6, 1957 2 Sheets-Sheet 1 INVENTOR. JnsEPH E. P01351112 April 14, 1959 J. E. PODGOR SILK SCREEN PRINTING MACHINE 2 Sheets-Sheet 2 Filed March 6, 1957 INVENTOR.

United States Patent SILK SCREEN PRINTING MACHINE Joseph E. Podgor, Philadelphia, Pa. Application March 6, 1957, Serial No. 644,255

2 Claims. (Cl. 101-126) My invention relates to a silk screen process printing machine, and, more particularly relates to a ballast system for the squeegee and printing frame wherein the printing of large quantities of sheets may be greatly accelerated.

The silk screen printing process utilizes a sheet of fabric screen which is stretched tightly upon a frame and has a stencilled portion through which paint may pass to form the design. Paint in a semi-liquid State is placed upon the stencilled screen at one end thereof and is drawn therefrom in a wave by a squeegee scraper. The paint thus drawn from the stencil fills the open pores of the pervious design portion of the stencil and adheres to the sheet to be imprinted.

The class of work turned out by apparatus of this description competes productionwise with other printing processes. However, since silk screen printing machines are hand operated, it is necessary for the squeegee assembly, as well as the printing frame, to be easily manipulated so that the operator may turn out a large quantity of work without undue strain in setting up the work sheets in sequence. While prior silk screen machines utilize balanced ballast systems, each of these were either expensive in manufacture or appeared clumsy with overhanging pulley systems.

It is, therefore, an object of my invention to provide a silk screen printing machine wherein the printing frame and squeegee assembly are uniformly balanced in all positions of the stroke or lifting operations.

Another object of my invention is to provide a silk screen printing machine that easily permits adjustment for any size printing frame.

Another object of my invention is to provide a carriage for the squeegee assembly wherein the suspension enables balanced manipulation during the stroke and lifting operations.

Another object of my invention is to provide a silk screen process printing machine wherein a minimum of pulley encumbrances are presented.

Another object of my invention is to provide a silk screen process printing machine wherein means are afforded to lift the squeegee assembly and printing frame simultaneously at the end of the stroke in each direction.

Another object of my invention is to provide a silk screen process printing machine wherein accurate registration of the printed matter is available for stroke in either direction.

Other objects of my invention are to provide an improved device of the character described, that is easily and economically produced, which is sturdy in construction, and Which is highly efiicient in operation.

With the above and related objects in view, my invention consists in the details of construction and combination of parts, as will be more fully understood from the following description, when read in conjunction with the accompanying drawing, in which:

Fig. 1 is a rear perspective view of a silk screen process printing machine embodying my invention.

Fig. 2 is a side view of the silk screen printing machine showing the frame in lifted position at the end of the stroke of the squeegee assembly.

Fig. 3 is a fragmentary view showing the hinged brackets for the printing frame.

Fig. 4 is an enlarged view showing the details of the carriage suspension.

Fig. 5 is a sectional view taken along lines 5-5 of Fig. 4.

Fig. 6 is a sectional view taken along lines 6-6 of Fig. 3.

Referring now in greater detail to the drawing in which similar reference characters refer to similar parts, I show a silk screen process printing machine comprising a table, generally designated as A, a printing frame mounting, generally designated as B, and squeegee assembly and suspension, generally designated as C, and a ballast balancing system, generally designated as D.

The printing table A is of conventional design having a surface top 10 supported upon four legs 12. It is upon the surface top 10 which the printing material 14 is placed directly below the frame assembly B.

The frame assembly B, comprises a stencilled screen 16, which is stretched tautly within a wooden frame border 18, the latter being hinged at its rearward portion to a pair of brackets B1 supported upon a longitudinally extending angle bar 20 at the back of the surface top 10. Each bracket B1 comprises a slotted member 22 and a clamp 23 pivotally connected to each other about a horizontal axis by a hinge 24. The member 22 is adjustably secured through its elongated slot to the angle bar 20 at one of a plurality of tapped holes 25 therein by passing the threaded end of a knurled stud 26 through the slot for threaded engagement with one of the tapped holes. This enables forward or rearward adjustment of the brackets B1 upon the table top. The slot member 22 is also pivotally connected about a vertical axis to the hinge 24 by a swivel bolt 27. Each clamp 23 comprises a plate 28 having a pair of apertured bosses 29 therein and a block 30, the block having a threaded stud 32 extending from one face thereof. The clamp 23 is secured to the rear of the painting frame 18 by passing the stud 32 through one of the holes 29 in the plate 28 and tightening a knurled knob 34 upon the threaded end of the stud 32. Thus, the printing frame 18 may be embraced by the clamp 23, and laterally positioned between the plate 28 and the block 30. It is thus to 'be noted that the printing frame assembly B has infinite degrees of freedom whereby any size printing frame 18 may be secured upon the table A and suitable adjustment being made in the bracket B1 to accommodate adjustment in any one of three planes.

A traverse rail 38, circular in cross section, is longitudinally supported immediately above the block 20 by a pair of supports 40 at its end points. Immediate inboard of supports 40, are a pair of arms 42, rotatably and slid ably supported upon the track 38 by a bearing 43, one end of each arm having a chain and snap fastener 44 which mounts on an eyelet secured upon each side of the printing frame 18. The other end of each arm 42 overhangs the back of the table A and each is connected to the pulley ballast system D, which will be described in greater detail hereinafter. It is also to be observed that each arm 42 at its rearward portion thereof has an inwardly extending member 46 mounted thereon, these arms detachably engaging the squeegee assembly C at the end of its stroke in either direction whereby lifting the squeegee will simultaneously raise the printing frame assembly B to the hinge brackets B1.

The arms 42 are each rectangular tubes having a plurality of spaced holes 45 longitudinally extending along the bottom surface thereof. The bearings 43 are mounted th ou h any pair oi the holes 45 hereby the length of the arms 42 may be adjusted to compensate for different width printing frames. As set forth above, the bearings 43 are also slidably mounted upon the track 38 in order to permit adjustment for different lengths of printing frames. Suitable rubber grommets 47 are slidably mounted upon the track 38 inboard of the arms 42. The grommets 47 'frictionally engage the track 38 and restrict further movement of the arms 44 toward each other after the latter have been positioned for a particular length printing frame.

The squeegee assembly C comprises a lever arm as,

which is slidably and hingedly supported upon the traverse rail 38 by a carriage suspension C1. A squeegee blade or scraper 50 is mounted upon the bottom of the lever arm 48'and adjustably secured thereto. The car i e S p ns on 01 omp ses a p i p s 2 and 54,. each end of which has a set of roller bars 56 con sisting of three rollers mounted. 120 apart from each other about the traverse rail 38. Thus the rollers 56 securely embrace the traverse rail 38 and enable the lever arm 48 to longitudinally slide along the table surface and permit pivotal raising of the lever arm in a plane at right angles to the table surface at any time. Therearward end of the lever arm 48 overhangs the back of the table A and has a ballast weight 58 adjustably mounted thereon to secure balancing of the squeegee assembly about its fulcrum. In the middle of its stroke, the squeegee assembly C is independent of the frame assembly B. However, at each end of its stroke, the squeegee assembly C permits engagement immediately above the inwardly turned member 46, whereby raising the forward end of the lever arm 48 will depress the rear of the arms 42 and cause the printing frame B to raise upwardly.

The pulley ballast system D is mounted solely to the printing frame assembly B through the arms 42 and do not co-act with the squeegee assembly C except at the end of its stroke when the lever arm 48 is raised. However, uniform balancing in any position is provided since the effective moment of the squeegee assembly is zero. The pulley ballast system D comprises a coil spring 60 which has a cord 62 mounted at each end thereof and extending through a pulley 64. secured to the back of the table. The cord 62 passes through each pulley 64 and extends downwardly through a pulley 66 secured upon the lower rear end of the table. The free end of each cord 62 then passes upwardly and is mounted upon an adjusting block 68 through a pair of holes therein. An adjusting cord 70 is also looped at one end through the upper hole of the adjusting block 68, the upper end ofthe cord 70 being secured to the rear of the arm 42. Looping the cord 7 0 through the block 68 permits minute adjustment of the pulley system D by convenientlydraw! ing tension on the coil spring 60 to, suit the balance of the printing frame assembly at any time.

As is, apparent from the foregoing description, balancing the tension of the coil. spring properly will permit the printing frame assembly B to be set in any vertical hinged position without falling or raising due to its functional adjustment of the pulley system B. As the squeegee is drawing longitudinally across the table and the scraper 50 hearing downward On the screen 16, the printing frame will remain fiat upon the printed sheet. At the end of the stroke, raising the lever arm 48 will cause lifting of the frame from the table top because of the engagement of the lever arm with the inwardly turned rods 46. Thus it is seen that simultaneous lifting of the frame may be accomplished when the squeegee is at the end of its stroke. By raising the lever arm about the wave of surplus ink and then lowering the lever arm on the opposite side thereof, the squeegee assembly is now in position to stroke in the opposite direction across the stencil 16 after the new work sheet has been placed in its proper position el the f ame 1.8-

Although my invention has been described in considerable detail, such description is intended as being illustrative rather than limiting, since the invention may be variously embodied, and the scope of the invention is to be determined as claimed.

I claim as my invention:

1. A silk screen process printing machine comprising a table, a printing frame assembly having a screen thereon, and a ballast system, said frame assembly being hingedly secured upon the back of said table by a pair of hinge brackets, a pair of arms pivotally and slidably secured to a traverse rail on the back of said table, the forward end of each of said arms being detachably connected to said printing frame assembly and the rear end of each of said arms overhanging the rear of said table, said ballast system comprising a coil spring having a cord attached to each end thereof and mounted to the back of said table through a series of pulleys, the outboard end of each of said cords being secured to the overhanging end of one of said arms, a squeegee assembly slidably and, hingedly mounted upon said rail and an inwardly turned member secured to the rear end of each of said arms, each of said members being engaged by said squeegee assembly at each end respectively of the stroke thereof, whereby raising said squeegee assembly will raise said printing frame.

2. The silk screen printing frame of claim 1 wherein said rail comprises a rod circular in cross section, said squeegee assembly having two sets of bearings therein embracing said rail, each set of bearings comprising three roller bearings mounted apart from each other upon said track.

References Cited in the file of this patent UNITED STATES PATENTS allm