Information
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Patent Grant
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4080893
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Patent Number
4,080,893
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Date Filed
Thursday, October 7, 197648 years ago
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Date Issued
Tuesday, March 28, 197846 years ago
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Inventors
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Original Assignees
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Examiners
Agents
- Price, Heneveld, Huizenga & Cooper
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CPC
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US Classifications
Field of Search
US
- 101 119
- 101 120
- 101 123
- 101 124
- 101 126
- 118 213
- 118 407
- 118 406
- 118 413
- 118 411
- 118 412
- 118 415
- 401 270
- 401 274
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International Classifications
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Abstract
A squeegee assembly for stencilling apparatus employing cooperative front and rear panels astraddle the squeegee, the panels being shiftable between (1) an extended condition away from the squeezee and in which such cooperatively form an open bottom chamber for the stencilling fluid about the squeegee, and also the rear panel serves as a flow coater and the front panel serves as a fluid barrier, and (2) a retracted position at the squeegee to close the fluid chamber about the squeegee. BACKGROUND OF THE INVENTIONThis invention relates to stencilling apparatus, and more particularly to a stencilling assembly with control of the stencil fluid.In recent years, several developments have been made in squeegee assemblies of stencilling apparatus to obtain better control of the stencil fluid characteristics during continued stencilling. Many of such developments have been directed to features for controlling the viscosity of the fluid by limiting exposure of the fluid to minimize solvent evaporation, by controllably adding solvent to the fluid for viscosity stabilization, by operating the squeegee while submerged under a pool of fluid, by flow coating directly behind the squeegee during the stencilling stroke, and others. Typical ones of these developments are set forth in U.S. Pat. No. 3,252,411, application Ser. No. 519,539, filed 10/31/74, now U.S. Pat. No. 3,980,017 issued Sept. 14, 1976, application Ser. No. 518,768, filed 10/29/74, now U.S. Pat. No. 3,973,491 issued Aug. 10, 1976, and application Ser. No. 688,610, filed 5/21/76.However, even with some of these improved devices, during the stencilling operation the relative movement occurring between the squeegee and the stencil screen (usually by moving the stencil screen past the squeegee), causes the stencil fluid to steadily accumulate on one end of the stencil where the squeegee stops at the end of the stencilling stroke. The accumulated fluid, usually ink, becomes viscous, thereby becoming not only useless but also presenting a cleaning problem. And, at high printing speeds, the ink is sometimes actually pushed or splashed against the end of the stencil frame to create further difficulties.SUMMARY OF THE INVENTIONThis invention was conceived and developed to achieve control of the stencilling fluid and its stencilling characteristics during repeat stencil strokes, even of the fluid pushed ahead of the squeegee. The fluid is retained within a confined chamber formed by cooperative front and rear panels straddling the squeegee and shiftable between extended and retracted conditions. The special front panel, in addition to its cooperative action with the rear panel in forming the chamber, forms a barrier to the excess fluid ahead of the squeegee when extended. It also retrieves this fluid when shifting to its retracted condition at the end of the stencilling stroke. The rear panel, in addition to its cooperative action with the front panel, spreads fluid during stencilling for the succeding stencilling stroke. The two panels, retracted to the squeegee, cooperate with the squeegee to form a closed bottom fluid chamber about the squeegee, enabling the squeegee to be of suspended submerged type with flow passage means thereabove in the squeegee support.The front and rear panels advance with the squeegee, that is, relative to the stencil, but spaced from the squeegee, during the stencilling stroke, and return with the squeegee in a fluid retaining relationship therewith on the return stroke. This relative movement may be and usually is achieved by shifting the stencil while retaining the squeegee and panels generally stationary.These and other special advantages, features, and objects of the invention will be apparent from the following detailed description.
Claims
- 1. A squeegee assembly for use with a stencil frame mounting a stencil screen, comprising:
- support means for supporting the squeegee assembly in a stencil frame;
- a squeegee retainer suspended from and spaced below said support means and configurated to retain a resilient squeegee element for cooperative relationship with the stencil screen;
- a pair of spaced, end members at opposite ends of said squeegee retainer to retain stencilling fluid;
- a pair of front and rear closure panels astraddle of said squeegee retainer, means operatively coupled with both of said front and rear closure panels for shifting said front and rear closure panels simultaneously between a cooperative retracted condition at said squeegee and squeegee retainer, forming a closed chamber for stencil fluid around said squeegee, and an extended condition with both said front and rear closure panels spaced from said squeegee retainer to form an open bottom chamber; said means for shifting including camming means comprising cam surfaces and cam surface followers connected to one of said front and rear panels, and second cam surfaces and cam surface followers connected to the other of said front and rear panels.
- 2. A squeegee assembly for use with a stencil frame mounting a stencil screen, comprising:
- support means for supporting the squeegee assembly in a stencil frame;
- a squeegee retainer suspended from and spaced below said support means and configurated to retain a resilient squeegee element for cooperative relationship with the stencil screen;
- a pair of spaced, end members at opposite ends of said squeegee retainer to retain stencilling fluid;
- a pair of front and rear closure panels astraddle of said squeegee retainer, means operatively coupled with both of said front and rear closure panels for shifting said front and rear closure panels simultaneously between a cooperative retracted condition at said squeegee and squeegee retainer, forming a closed chamber for stencil fluid around said squeegee, and an extended condition with both said front and rear closure panels spaced from said squeegee retainer to form an open bottom chamber; said front panel in its extended condition forming a fluid retaining splash panel, and said rear panel forming a flow coater.
- 3. A squeegee assembly comprising:
- a stencilling-fluid chamber having spaced, generally vertical front and rear panels, and cooperative end panels;
- a squeegee retainer and squeegee between said front and rear panels and between said end panels;
- means for simultaneously shifting said front and rear panels between an extended position both spaced from said squeegee retainer and squeegee to form an open bottom chamber for stencilling, and a retracted position at said squeegee retainer and squeegee to form a closed bottom fluid retaining chamber; said front and rear panels having portions extending vertically above portions of said squeegee retainer to cause said chamber to have portions in front of, to the rear of, and above said squeegee retainer portions.
- 4. A squeegee assembly comprising:
- a stencilling-fluid chamber having spaced, generally vertical front and rear panels, and cooperative end panels;
- a squeegee retainer and squeegee between said front and rear panels and between said end panels;
- means for simultaneously shifting said front and rear panels between an extended position both spaced from said squeegee retainer and squeegee to form an open bottom chamber for stencilling, and a retracted position at said squeegee retainer and squeegee to form a closed bottom fluid retaining chamber; said rear panel and said panel and said panel shifting means being operatively interconnected to elevate said front panel slightly when said panels are extended, to cause said front panel to clear the fluid flow coated during the previous stencilling stroke.
- 5. The apparatus in claim 4 wherein said panel shifting means includes cam tracks and followers to so elevate said front panel.
US Referenced Citations (3)