US3273536A

US3273536A - Trailing-blade coater including fluid seal

Info

Publication number: US3273536A
Application number: US119431A
Authority: US
Inventors: Merrill F Galer; Morrison N Stiles
Original assignee: Time Inc
Current assignee: TI Gotham Inc
Priority date: 1961-06-26
Filing date: 1961-06-26
Publication date: 1966-09-20
Anticipated expiration: 1983-09-20

Description

Sept. 20, 1966 F. GALER ETAL 3,273,536

TRAILING-BLADE COATER INCLUDING FLUID SEAL Filed June 26, 1961 5 Sheets-Sheet 1 INVENTORS MERRILL F. GALER N MORRISON N.ST|LES QMLA/ZM 4%,, Quid THEIR ATTORNEYS Sept. 20, 1966 M, F. GALER ETAL TRAILING-BLADE GOATER INCLUDING FLUID SEAL Filed June 26, 1961 5 Sheets-Sheet 2 INVENTORS MERRILL F. GALER MORRISON N.STILE.S

THEiR ATTORNEYS p 20, 1966 M. F. GALER ETAL 3,273,536

TRAILING-BLADE COATER INCLUDING FLUID SEAL Filed June 26, 1961 5 Sheets-Sheet 5 if Max angle 0 pressure I so -M|n.unge pressure 35-102 Blade Sponge Rubber INVENTORS. MERRILL E GALER THEIR ATTORNEYS MORRISON N. STILES United States Patent 3,273,536 TRAILING-BLADE COATER INCLUDING FLUID SEAL Merrill F. Galer, Monroe, and Morrison N. Stiles, Westport, Conn., assignors to Time Incorporated, New York, N.Y., a corporation of New York Filed June 26, 1961, Ser. No. 119,431 4 Claims. (Cl. 118-413) This is a continuation-in-part of the copending, but now abandoned application, Serial No. 720,587, filed March 11, 1958.

This invention relates to a spreading or coating apparatus embodying a novel blade-clamping and controlling apparatus in which the blade is resiliently clamped and acted on by an adjustable pressure-exerting means which not only makes it possible for the blade to align itself with the surface to be coated, but affords a control over the Weight or thickness of the coating applied by the blade not heretofore available in conventional coating apparatus. The invention also relates to a novel blade-clamping apparatus in which provision is made for supplying a sealing fluid to the end walls of the blade support so that a suitable seal can be obtained without impeding the freedom of movement of the blade.

In conventional coating apparatus, the coating blade is usually firmly clamped against a blade support in position such that the coating edge of the blade projects beyond the blade support. In this conventional type of coating apparatus, the only control over the weight or thickness of the coating material applied to the surface to be coated (aside from the choice of Web, coating material and speed) is obtained by positioning the blade support so as to regulate the pressure engagement between the blade and the surface to be coated. This conventional coating apparatus does not give adequate control over the blade, and moreover, due to the rigid manner in which the blade is clamped causes the irregularities in the blade such as defects in the edge, ripples, or localized strength discrepancies to show up as defects in the coating The problems encountered in the use of conventional blade-clamping apparatus in which the blade is rigidly clamped against a blade support can be illustrated by reference to FIGURE 1A of the drawings. Such rigidly clamped blades are characterized by pressure flaws inherent in the blade itself and in its support. For example, the uniformity of pressure exerted by the blade edge E against the cylinder C is influenced by:

(1) the parallel relationship of the line A of the clamp I with the blade edge;

(2) the parallel relationship of the line B of the blade support P with the blade edge;

(3) the evenness of strength in the entire bladefrom edge to back and side to side-(indicated by K); and

(4) the edge characteristics of the blade at or adjacent to the line E, particularly its freedom from ripples and minute cavities.

The blade-clamping apparatus of the present invention provides a resilient clamping means for a blade capable of limited movement on a blade support. The blade support carries an adjustable pressure-exerting means which acts against the blade and urges the coating edge thereof against the backup cylinder or the surface to be coated, thereby causing the blade to come into the desired pressure engagement with the surface to be coated. In addition, the clamped edge of the blade is permitted the necessary freedom of movement to permit the blade to arch slightly, the arched blade having the advantage of minimizing the effect of any irregularities of the blade and the blade edge. By virtue of this adjustment of the blade, the bladeclamping apparatus of the present invention provides not 3,273,536 Patented Sept. 20, 1966 only an excellent means for controlling the weight or thickness of the film of coating material applied by the blade, but it accomplishes this result in a way which makes it possible for the blade to align itself properly with the surface to be coated and also in a way which minimizes the effect of imperfections in the blade.

An ancillary feature of the present. invention is that it provides means for supplying a sealing fluid to the end walls of the blade support so that a suitable seal can be obtained without impeding the above-described adjustment of the blade. Since the preferred embodiment of the present invention the coating material is supplied to the surface to be coated across the upper surface of the blade and between end Walls or dams, it is important that the end walls do not interfere with the necessary movement and deflection which must be imparted to the blade. Accordingly, the present invention provides an elastic seal in the form of a fluid which is effective while at the same time affording the necessary freedom of movement to the blade.

For a complete understanding of the present invention, reference can be made to the detailed description which follows and to the accompanying drawings, in which:

FIGURE 1 is a perspective view of a coating apparatus constructed in accordance with the invention;

FIGURE 1A is a diagrammatic illustration of a conventional blade-clamping apparatus;

FIGURE 2 is a view taken along FIGURE 1;

FIGURE 3 is a view taken along FIGURE 2;

FIGURE 4 is an enlarged portion of FIGURE 3;

FIGURE 5 is a schematic view which illustrates the principle of the present invention;

FIGURE 6 is a cross-sectional elevation of an alternative embodiment of the invention in which the section is taken through an end wall of the apparatus;

FIGURE 6A is an enlarged fragmentary view of a portion of FIGURE 6; and

FIGURE 7 is a perspective view similar to FIGURE 2, but of the alternative embodiment shown in FIGURE 6.

Referring now to FIGURE 1 of the drawings, a blade support, indicated generally by the numeral 10, is provided with end walls or dams 11 and 12 spaced apart from each other and attached to the opposite ends of a base 13.

Blocks

14 and 15 are mounted on the inner sides of the end walls 11 and 12, respectively. The arcuately

curved front edges

16 and 17 of the end walls 11 and 12, respectively, are contoured in complementary fashion to the closely spaced curved surface of the cylinder to confine the coating material between the end walls as it is supplied to a web in contact with the cylinder. However, a more effective seal is provided between the end walls and the cylinder by

felt pads

18 and 19 attached to arcuate edges of the

blocks

14 and 15.

A coating blade 20 is carried by the blade support between the end Walls 11 and 12, and the ends of the blade are accommodated between the base 13 and the lower edges of the

blocks

14 and 15. Thus, the upper surface of the blade and the inner surfaces of the end walls cooperate to form a reservoir for the feed by pressure or by gravity of the coating material to the coating edge of the blade and thence onto the web to be coated.

A blade clamp or pressure strip 25 is secured rigidly to the base 13 by screws 26, and the clamp carries a resilient strip 27 (e.g., of foam rubber) inset in the forward bottom edge of the clamp which engages the rear edge 21 of the blade. In addition, the base 13 carries a plurality of spaced-apart pins 22, the lower ends 23 of which are threaded into the base. These pins pass through corresponding but over-sized holes in the rear edge of the blade, and the upstanding ends of the pins are re the line 2-2 of the line 33 of 3 ceived in over-sized holes 24 of the clamp 25. The resilient clamp and the over-sized holes of the blade permit limited freedom of movement to the blade when the tube 29 is not inflated.

When the blade support is mounted in its operative position in proximity to the web backup cylinder, the coating edge 28 of the blade 20 is pressed against the web by an inflatable neoprene tube 29 partially recessed in the base 13 of the blade support. The coating edge of the blade overhangs the tube 29 slightly. The inflatable tube serves as an adjustable means of controlling the pressure of the blade against the web and the backup cylinder. As illustrated in FIGURE 5 of the drawings, before air pressure is introduced into the inflatable tube, the blade is substantially straight and in light pressure engagement with the cylinder. As the air pressure is increased in the inflatable tube, the coating edge of the blade is held between the cylinder and the tube, and the blade begins to deflect -or arch. Because of the resiliency of the operative portion of the clamp and the limited freedom of movement afforded to the blade by the pins in the over-sized holes, tl1e clamped edge of the blade is capable of accommodating itself to this deflection or arching of the blade. In a typical example, an increase in the air pressure of the tube from 0 lb. to 30 lb. pressure will lift the coating edge a of the blade approximately .050 in., the high point 17 of the blade about .132 in. and will change the angle x of the blade about 6, or in other words, change the angle which the blade makes with a line tangential to the cylinder from about 60 to about 54 as shown in FIGURE 5.

Delicate control over the weight or thickness of the coating material can be exercised by regulating the pressure supplied to the inflatable tube. Moreover, as the blade arches as the result of the inflation of the tube, imperfections in the blade (ripple, for example) are corrected and the blade tends to self-align itself with the backup cylinder. Moreover, in operation the inflatable tube serves as a relatively soft backup cushion for the cylinder which improves the uniformity of the coated film.

Another important feature of the coating apparatus of the present invention is the elastic seal provided at the front ends of the blade 20. This seal is effective to form an enclosed reservoir which is defined by the two

end blocks

14 and 15 of the walls 11 and 12, respectively, of the blade and the web to be coated. Essentially, this seal is provided by supplying a sealing fluid under pressure to the front edges of the end walls, specifically to the space or slot 30 between the upper surface of the blade and the lower edges of the

blocks

14 and 15, the pressure causing the fluid to flow toward the cylinder. The sealing fluid can be air, grease or other suitable fluid which will afford the blade the necessary freedom of movement.

In the embodiment shown in FIGURES 3 and 4 of the drawings, the sealing fluid is supplied through a passage 31 in communication with a sealing fluid supply under pressure to a arcuate recess 32 in the upper surface of the base 13 near the coating edge of the blade. The rear half of the recess 32 is filled by a plug 33 to insure that the sealing fluid will be directed toward the coating edge of the blade. A hole 34 in the blade above the recess 32 affords the sealing fluid access to the slot 30.

It is apparent that the passage which supplies the sealing fluid to the slot or space 30 can be formed in the end walls 11 and 12, or the

blocks

14 and 15, in which case it will not be necessary to provide the holes 34 in the blade.

By way of illustration, in the embodiment shown in FIGURES 6 and 7 of the drawings, each of the end walls 11 and 12 is provided with a passage 36 therethrough which establishes communication between a source of the sealing fluid under pressure and the slot or space 30 between the bottom edge of the

respective block

14 or 15,

as the case may be, and the upper surface of the blade.

The invention has been shown in preferred form and by way of example only, and obviously, many variations and modification may be made therein without departing from the spirit of the invention. The invention, therefore, is not to be limited to any specified form or embodiment, except insofar as such limitations are set forth in the claims.

We claim:

1. A coating apparatus which cooperates with a rotatable cylinder serving as a back-up surface for a web to be coated comprising a coating blade, a coating blade support holding the coating blade in position to engage the web, a pair of end walls carried by the blade support adjacent the rotatable cylinder to confine the coating material therebetween, means defining a slot in the base of each end wall to receive the side edge of the blade therein, the height of the slot being greater than the thickness of the blade, the coating blade protruding forwardly of the end walls in the direction of movement of the cylinder and the web against the cylinder and defining a space forward of each end wall between the blade and the surface to be coated, the forward end of each said slot communicating with one of said spaces, and passage means establishing communication between a source of fluid under pressure for supplying the fluid to said space to provide a fluid seal for said space.

2. A coating apparatus as set forth in claim 1 including an inflatable tube accommodated by the blade support and acting against the blade along the length of the blade to load the coating edge of the blade against the web to be coated, the height of the said slots permitting the coating blade to deflect as the loading pressure increases.

3. A coating apparatus as set forth in claim 1 including resilient means along the length of the blade and engaging the blade remote from the coating edge, the resilient means permitting deflection of the coating blade between the coating edge and the edge opposite the coating edge.

4. A coating apparatus as set forth in claim 1 includ ing a plurality of pins mounted in the blade support and spaced along a surface of the blade support, and means defining oversized holes in the blade along the edge opposite the coating edge to receive the pins and afford the blades limited movement relative to the blade support.

References Cited by the Examiner UNITED STATES PATENTS 1,566,358 12/1925 White 118 1,883,167 10/1932 Vickery 15256.51 1,912,605 6/1933 Vickery 15--256.51 2,077,816 4/1937 Vickery I- 118 2,081,320 5/1937 Burgess 188 2,176,418 10/1939 Daley 118-262 2,328,183 8/1943 Barrett 118413 2,329,277 9/1943 Lodding 118 2,431,900 12/ 1947 Worthington 101210 2,487,409 11/1949 Baker 15-256.51 2,579,181 12/1951 Faeber 101151 2,732,773 1/ 1956 Smith 15256.51 2,890,473 6/1959 Scott 118-261 X 2,914,788 12/1959 Smith et al 118 2,948,012 8/1960 Scott 15-256.51 3,026,942 3/ 1962 Faeber 118407 X 3,032,007 5/1962 McCaulitf 118259 X 3,070,066 12/1962 Faeber 118413 MORRIS KAPLAN, Primary Examiner.

JOSEPH B. SPENCER, RICHARD D. NEVIUS,

Examiners.

J. A. HAUG, Assistant Examiner.