US3017823A

US3017823A - Screen stencilling machine

Info

Publication number: US3017823A
Application number: US802916A
Authority: US
Inventors: Farwell Harry Russell
Original assignee: Individual
Current assignee: Individual
Priority date: 1959-03-30
Filing date: 1959-03-30
Publication date: 1962-01-23
Anticipated expiration: 1979-01-23
Also published as: DE1808730U

Description

Jan. 23, I962 Filed March 30, 1959 H. R. FARWELL 3,017,823 SCREEN STENCILLING MACHINE 4 Sheets-Sheet 1 I INVENTOR zwwellfavwe ll Hang BY filed 01,3026

ATTORNEY Jan. 23, 1962 H. R. FARWELL 3,017,823

SCREEN STENCILLING MACHINE Filed March so, 1959 4 Sheets-Sheet 2 BY fiuwwmf ATTORNEY Jan, 23,1962- H. R. FARWELL.

SCREEN STENCILLING MACHINE Filed March 30, 1959 4 Sheets-Sheet 3 ATTORNEY Jan. 23, 1962 H. R. FARWELL 3,017,823

SCREEN STENCILLING MACHINE Filed March so, 1959 4 Sheets-Sheef 4 INVENTOR Hat-g Rad-yell Farulell United States Patent 3,017,823 SCREEN STENCIILLING MAQHINE Harry Russell Farwell, Grand Rapids, Mich, assignor to James A. Black, Grand Rapids, Mich. Filed Mar. 30, 1959, Ser. No. 802,916 11 Claims. (1. 101-123) The present invention relates to screen stencilling machines.

The primary objects of the invention are to provide an improved screen stencilling machine of the same general type as the machines disclosed in co-pending applications Serial No. 748,188 and Serial No. 748,360, both filed on July 14, 1958 by the assignee of this application, James A. Black; to provide such a machine which, with the appli cation thereto of appropriate jigs, fixtures or conveyor mechanisms, is adaptable for the semi-automatic silk screening onto a wide variety of articles including flat stock and irregularly shaped stock, and which may even be adapted for the continuous repetition of an impression on tape, ribbon or the like; to provide such a machine in which the movements of the various moving parts are automatically timed and co-ordinated; to provide a novel silk screen mounting frame for such a machine; and in general to provide such a screen stencilling machine which is eflicient in operation, reasonably economical in manufacture, and attractive in appearance.

A11 illustrative embodiment of the invention is shown in the accompanying drawings, wherein:

FIGURE 1 is a top plan view of the machine with a portion of a stock-centering fixture mounted on the machine broken away to better reveal the stencil and stencil frame of the machine;

FIGURE 2 is a vertical sectional view of the machine taken on lines 2-2 of FIGURES l and 3;

FIGURE 3 is a vertical sectional view thereof taken on line 3-3 of FIGURE 2;

FIGURE 4 is a vertical sectional view of parts of the machine taken on line 4-4 of FIGURE 3, and having an electric circuit superimposed thereon diagrammatically;

FIGURE 5 is a vertical sectional view of the machine similar to FIGURE 2 but showing certain movable parts thereof in different positions; and

FIGURE 6 is a fragmentary vertical sectional view similar to FIGURES 2 and 5 and showing the movable parts thereof in still other positions.

Referring now in detail to these drawings, the machine comprises an upwardly opening box 10 mounted on a base 11 having supporting feet 12 and the box 10 comprises a bottom 13, parallel vertical side walls 14, 15 and parallel vertical end walls 16, 17. A cover or top It; is secured to the top of the box 10 by means of screws 19 passing through

flanges

20, 21 extending outwardly from the upper ends of the end walls 16, 17 of the box and into the top 18. The top 18 provides a work-supporting upper surface, and it has a rectangular opening 22 therethrough which is in registry with the open upper end of the box 10 and which opening is adapted to receive the screen stencil and its frame.

The rectangular stencil frame 23 comprises four straight strips of upwardly opening channel stock mitered to fit at the corners and secured together as by welding. The frame thus presents a continuous upwardly opening channel 24. The stencil 25, which may be of silk or fine mesh wire, is stretched taut over the top of the stencil frame 23 and is secured to the frame by means of cording 26 which is pressed into the channel 24 with the marginal edges of the stencil 25 clamped in the channel. The stencil is thus readily applied to the frame and can be quickly removed therefrom whenever 3,617,823 Patented Jan. 23, 1962 it is desired to replace it with a different stencil. The stencil 25 and its frame 23 are removably mounted in the opening 22 in the top 18 by means of a central locating screw 27 threaded in the top 18 at one end of the opening 22, and a pair of bullet catches 28 in the top at the other end of said opening. The screw 27 and bullet catches 28 enter apertures in the outer flanges of the stencil frame 23. When so mounted, the stencil frame 23 rests on the upper edges of the box 10.

A rock shaft 29 has its opposite ends journalled in the lower middle regions of the side walls 14, 15 of the box It). A pair of rocker arms 30, 31 are fixedly mounted on the rock shaft 29 and extend upwardly therefrom adjacent the opposite side walls of the box. The rocker arms have longitudinally extending

slots

32, 33 at their upper ends. A pair of tracks 34, 35 are pivotally connected at 36, 37 to the opposite side walls 14, 15 respectively of the box 10, between the rocker arms and said side walls. The squeegee assembly extends transversely across the box 10 beneath the screen stencil 25 and comprises a shaft 38, a squeegee holder 39 fixedly mounted on the shaft 38, a rubber squeegee blade 40 seated in a slot in the holder 39, and a pair of

elongated slides

41, 42 fixedly mounted at the opposite ends of the shaft 38 and slidably disposed on the tracks 34, 35 respectively.

A camshaft 43 has its opposite ends journalled in the opposite side walls 14', 15 of the box 10 beneath the pivoted tracks 34, 35 and above and to the right of the rock shaft 29 as seen in FIGURES 2, 5 and 6. The camshaft 43 carries a pair of identical elevator cams 44, 45 and also a pair of identical rocker earns '46, 47, all fixedly mounted on the camshaft 43 and rotatable therewith. A pair of elevator cam followers 48, 49 is rotatably mounted on the lower ends of arms 50, 51 dependingly secured to the tracks 34, 35 respectively, and these elevator cam followers bear against the upper surfaces of the elevator cams 44, 45. A pair of rocker cam followers 52, 53 is rotatably mounted on the rocker arms 30, 31 and bear against the outer surfaces of the rocker cams 46, 47.

A paint tray 54 is removably mounted within the box 10 and beneath the squeegee assembly and is a reservoir for the coating material used in the screening process. The tray 54 has a pair of depending brackets 55 which are secured between

nuts

56, 57 secured on bolts 58 extending through the end wall 17 of the box 10. The other end of the paint tray rests on studs 59 secured by nuts 60, 61 to the opposite end walls 16 of the box 10. A pair of

bearing brackets

62, 63 is secured as by welding to the opposite side walls of the tray 54. A paint distributor 64 has a shaft 65 extending transversely of the paint tray and journalled at its opposite ends in the

bearing brackets

62, 63 for rocking movement. This distributor 64 has oppositely extending

longitudinal arms

66, 67 and a transverse distributing arm 68 mounted at the extremity of the longitudinal arm 66 seen at the left in FIGURES 2, 5 and 6.

Springs 69, 70 are each connected at one end to one of the rocker arms 30, 31 and at the other end to eyelet screws 71, 72 secured to the end wall 17 of the box 10 by means of nuts 73. These springs normally urge the rocker arms 30, 31 toward the right as viewed in FIG- URES 2, 5 and 6.

Driving means, best seen in FIGURES 3 and 4, are provided for driving the camshaft 43 and thus actuating the various moving parts of the machine. These means comprise an electric motor 74 mounted on the base 11, the shaft 75 of which motor carries a worm 76 meshing with a worm gear 77 on a shaft 78 extending through an enclosing gear box 79 also mounted on the machhies base 11 as here shown. Exteriorly of the gear b0x 79, the shaft 78 carries a gear 80 which meshes with a gear 81 on the camshaft 43 exteriorly of the box 10. A cam 82 on the camshaft 43, automatically operates a microswitch 83, the function of which is described hereinafter.

A locating fixture generally designated 84 is shown in FIGURES 1, 2 and 3 and is secured to the top 18 by means of machine screws 85 passing through slots 86 in the top 18 (see FIGURES 1 and 2). This fixture is universally adjustable so as to receive practically any type of jig constructed so as to properly locate the particular type of stock being printed, and in proper registry with the screen stencil. Such a jig, designated 87 is provided for locating the cylindrical objects 88 shown in the drawings. A plate 89 is here shown secured to the underside of the jig 87 for supporting the marginal edges of the objects 88 while they are being printed. Almost any type of jig, fixture or conveyor may be secured to the upper work-supporting surface of the machine, depending upon the character of the stock to be run. Hence the fixture shown in FIGURES 1, 2 and 3 is not described in detail herein.

Operation Stock to be printed, such as the cylindrical objects 88 shown in the drawings, is placed one object at a time in the jig 87 for screening of any kind of design or legend thereon such as company name and insignia, instructions, and trade marks like that shown in FIGURE 1. An electric switch 90 shown diagrammatically in FIGURE 4, which may be either manually or pedally operated, is then momentarily closed thus closing a circuit from a suitable source of electricity indicated by wires 91, 92, through

wires

91, 92, 93 and 94 to the electric motor 74, thus energizing the motor to drive camshaft 43 clockwise and start the print stroke of the machine. When the high point 95 of cam 82 reaches the microswitch 83, this switch is closed thus automatioaliy maintaining a closed circuit through the motor, through the microswitch 83 and through

wires

91, 94, 96, 97 and 92, and this circuit remains closed until the print stroke of the machineto the left as seen in FIGURES 2, and 6is completed. During this print stroke, elevator earns 44, 45 maintain tracks 34, 35 in elevated positions thus pressing the squeegee blade 40 into contact with the screen stencil and forcing coating material upwardly through the stencil and onto the stock. The rocker cams 46, 47 move the rocker arms 30, 31 and the squeegee assembly to the left during this print stroke, and in this movement the squeegee assembly depresses the longitudinal arm 66 of the rocking paint distributor 64 so that the transverse distributing arm 68 thereof is immersed in the coating material in the paint tray 54, as seen in FIGURE 5.

Upon the completion of the print stroke, cam 82 opens the microswitch 83 and the electric circuit through the motor 74, thus de-energizing the motor. Springs 69, 70 then take over and return the rocker arms 30, 31 and the squeegee assembly to their starting positions, effecting the non-print stroke of the machine with a quick snap-action. During this movement, elevator cams 44, 45 lower tracks 34, as seen in FIGURE 5 thus lowering the squeegee blade out of contact with the screen stencil 25, and the squeegee assembly is returned to its starting position by rocker arms 30, 31, the assembly at this time moving along the upper side edges of the paint tray 54 on

bronze bearings

98, 99 secured on the squeegees shaft 38 (see FIGURE 3). Tracks 34 and 35 are slowly raised to their starting positions by elevator cams 44, during this returning movement. Also during this returning, non-print stroke of the machine, the squeegee assembly strikes the longitudinal arm 67 of the paint distributor 64, thus quickly flipping the distributor to its starting position and splashing coating material across the underside of the screen stencil 25 in preparation for the next print stroke of the machine.

Having thus described the construction and operation of one preferred embodiment of my invention, I desire to secure by Letters Patent that embodiment and all such modifications thereof as fall within the spirit of the invention and the scope of the following claims.

I claim:

1. In a screen stencilling machine: upwardly extending substantially parallel side walls; a top mounted at the upper ends of the side walls and having a stock-supporting upper surface and an opening therethrough in registry with the opening between said side walls; a screen stencil mounted in the opening in said top; a pair of tracks pivotally mounted on said side walls respectively near corresponding ends thereof; and a squeegee assembly extending transversely between said side walls and having elements at its opposite ends reciprocable longitudinally on said tracks to effect print and non-print strokes of the squeegee beneath said stencil, said tracks being swingable about their pivotal mountings on the side Walls to elevated positions wherein the squeegee forces coating material upwardly through the stencil and onto stock placed on the stock-supporting upper surface of the top during the squee-gees print strokes, and said tracks being swingable to lowered positions wherein the squeegee is lowered out of contact with the stencil during the squeegees non-print strokes.

2. A screen stencilling machine according to claim 1 characterized by having a camshaft extending transversely between the side walls beneath said pivoted tracks, a pair of identical elevator cams on said camshaft, and a pair of elevator cam followers on said tracks bearing against said elevator cams whereby rotation of the camshaft raises and lowers said tracks in unison.

3. In a screen stencilling machine: upwardly extending substantially parallel side walls; a top mounted at the upper ends of the side walls and having a stock-supporting upper surface and an opening therethrough in registry with the opening between said side walls; a screen stencil mounted in the opening in said top; a rock shaft having its opposite ends journalled in the lower middle regions of said side walls; a pair of rocker arms mounted on the rock shaft and extending upwardly therefrom adjacent the side walls respectively; a squeegee assembly extending transversely between the upper ends of the rocker arms and reciprocable therewith beneath the stencil to effect print strokes and returning non-print strokes; and means for elevating the squeegee into contact with I the stencil to force coating material upwardly through the stencil and onto stock placed on the stock-supporting upper surface of the top, said means also operating to lower the squeegee out of contact with the stencil during said returning non-print strokes.

4. A screen stencil machine according to claim 3 characterized by having a camshaft extending transversely between the side walls, a pair of identical rocker cams on said camshaft, and a pair of rocker cam followers on said rocker arms bearing against said rocker cams whereby rotation of the camshaft moves the rocker arms in unison in the print stroke direction.

5. A screen stencil machine according to claim 4 including spring means for moving the rocker arms in unison through their returning non-print strokes.

6. In a screen stencilling machine: an upwardly opening box; a top mounted on the box and having a stocksupporting upper surface and an opening therethrough in registry with the open upper end of the box; a screen stencil mounted in the opening in said top; a squeegee mounted in the box for reciprocating movements beneath the stencil to effect print strokes wherein coating material is forced upwardly through the stencil and onto stock placed on the stock-supporting surface of the top, and returning non-print strokes; a tray disposed in the box beneath the squeegee for containing the coating material; and a distributor mounted in the tray for rocking movement and having oppositely extending longitudinal arms and a transverse distributing arm at the extremity of one longitudinal arm, the squeegee being adapted to contact said longitudinal arms alternately during its reciprocating movements to rock the distributor so that during the print stroke the distributing arm is lowered into the coating material in the tray, and during the non-print stroke the distributing arm is flipped upwardly to splash coating material onto the underside of the stencil.

7. A screen stencilling machine according to claim 6 in which spring means are provided for rapidly moving the squeegee through its non-print stroke to that the distributing arm is flipped quickly upwardly.

8. In a screen stencilling machine: an upwardly opening box having a bottom, end walls, and substantially parallel side walls; a top mounted on the box and having a stock-supporting upper surface and an opening therethrough in registry with the open upper end of the box; a screen stencil mounted in the opening in said top; a rock shaft having its opposite ends journalled in the lower middle regions of said side walls; a pair of rocker arms mounted on the rock shaft and extending upwardly therefrom adjacent the opposite side walls of the box, said rocker arms having longitudinally extending slots at their upper ends; a pair of tracks pivotally mounted on said opposite side walls near one end of the 'box; and a squeegee assembly extending transversely in the box beneath the stencil and having slides at its opposite ends movable longitudinally on said tracks, said squeegee assembly having also pins extending into the slots in said rocker arms whereby reciprocation of the rocker arms reciprocates the squeegee beneath the stencil to effect print and non-print strokes, said tracks being swingable about their pivotal mountings on the side walls to elevated positions wherein the squeegee forces coating material upwardly through the stencil and onto stock placed on the stock-supporting upper surface of the top during the squeegees print stroke, and said tracks being swingable to lowered positions wherein the squeegee is lowered out of contact with the stencil during the squeegees nonprint strokes.

9. A screen stencilling machine according to claim 8 characterized by having a camshaft extending transversely between the side walls of the box beneath said pivoted tracks, a pair of identical elevator cams and another pair of identical rocker cams all mounted on said camshaft, a pair of elevator cam followers on said tracks bearing against said elevator cams and a pair of rocker cam followers on said rocker arms bearing against said rocker cams, whereby rotation of the camshaft raises the tracks so that the squeegee is elevated into contact with the stencil and then moves the rocker arms and the squeegee in the print stroke direction and whereby the squeegee is lowered out of contact with the stencil at the end of the print stroke.

10. A screen stencilling machine according to claim 9 including spring means for rapidly returning the rocker arm and squeegee through their non-print strokes.

11. A screen stencilling machine according to claim 10 in which revolving movement of the camshaft is efiected by an electric motor included in a circuit which also includes a switch for starting the motor and means for automatically stopping the motor upon the completion of the print stroke.

References Cited in the file of this patent UNITED STATES PATENTS 758,798 Tripp May 3, 1904 1,490,400 Owens Apr. 15, 1924 1,508,116 Nantus Sept. 9, 1924 1,556,998 Katcher Oct. 13, 1925 1,861,610 Respess June 7, 1932 2,039,909 Kern et al. May 5, 1936 2,545,277 Hannah et al Mar. 13, 1951 2,606,492 Black Aug. 12, 1952 2,613,596 Meissner Oct. 14, 1952