US2511717A - Coating process and apparatus - Google Patents

Description

E. S. KlLLlAN June 13, 1950 COATING PROCESS AND APPARATUS Filed July 50, 194'? A OEA/E YS Patented June 13, 1950 UNITED STATE S PATENT GFFICE COATING PROCESS lAND APPARATUS Edward S. Killian, Akron, Ohio, assignor to Frank B. Killian & Company, Akron, Ohio, a partnership Application July 30,

Claims.

1947, srial =No.`764,717

` implementing that method.

It has hereinto been customary in making balloons, finger cots, gloves, nipples and similar articles of rubber, to immerse a form in liquid latex and then to lift the form from the latex and cause the film adhering to the form to dryand solidify. It has been found that circulation of the liquid latex is important to the production of satisfactory latex lm's, especially if the dipping operation is carried out over an extended period and involves repeated dipping of forms into the liquid latex, in accordance with present commercial manufacturing operations. The forms inhibit rather than promote such circulation of liquid latex and, as a result, films formed on the forms often contain air bubbles and other weakening defects which may render the resulting articles worthless, or at least materially reduce their value and usefulness. Furthermore, the temperature of the liquid latex, which is rather critical within a certain range of temperatures, so far as the character of the articles produced is concerned, is difiicult to control in conventional practice due to the repeated immersion of forms which ordinarily have a temperature substantially higher than the maximum desirable latex temperature.

By virtue of the present invention, which is predicated upon my discovery that it is not necessary to completely immerse a form to produce satisfactory latex lms and rubber articles, thef difliculties aforementioned may for the rst time be overcome. In addition, the present invention enables much more rapid production of thin rubber articles than has ever heretofore been possible.

Brieiiy stated, the method of my invention includes the steps of moving sideways a substantially horizontally disposed revolving form, and flowing a dipping bath lengthwise of the form from' its supported end to its free end and in contact with the lower part of the form.

In carrying out this method to produce a rubber prophylactic, I have disposed a suitable form at a small angle to a dipping bath of liquid latex so that the lower part of the free end of the form is immersed in the liquid, and so that the lower part of the body of the form is in contact with the liquid to the extent necessary to produce an article of the length desired. The opposite end of the form is supported and .the form is simul- 1 taneously rotated and moved sideways while the form is in contact with the bath. The liquid latex is caused to flow substantially horizontally in a direction substantially at right angles to the sideways movementof the form and along the form from the supported portion to the free end thereof. Under these circumstances the form has the effect of dampening any wave motion in the bath,

' and the tendency for uneven deposition of, or

bubble inclusions in, latex upon the form is substantially overcome because the resistance to liquid latex flow by the form is substantially at a minimum. The manner in which the form is disposed with respect to the bath and the manner inl which the bath is circulated with respect to the form are responsible for the success of the method of my invention in producing thin rubber result from movingthe forms in the same directionlas the ow of the portion of the bath in contact with the forms, provided that the relative movement of the bath and forms is not too great. Similarly, the forms 'may be moved at an angle 'between these two extremes, that is, between purely sideways movement and axial movement. In the practice of this method, I have found it desirable to expose the upper portions of the forms in contact with liquid latex to drying circumstances. In this manner, by regulating the rate of rotation of the forms I have been able to produce exceptionally strong and durable rubber articles due, I believe','to the fact that instead of a` single lm such as is obtained in conventional dipping practice, my articles are formed of a plurality of individual films securely bonded together.

As the form is rotated so that said lower portion gradually becomes the upper portion and contacts the atmosphere under drying conditions, the film of latex adhering to said lower portion of form is dried or partially dried, and as the form rotates furtherthat film is immersed in the latex and dried or partially dried prior to the deposition of still another film.

By adjusting the length of the period of contact of'thev form'withr the dipping bath through regulation of the rate of travel and rotation of uniformity of films deposited on the forms. Also, the forms may be passed through the successive l stages described in that patent to "thoroughly process and finish the films.

The novel apparatus of thiszinventiom` by means of which I have successfully carried out the foregoing method, will be better understood by those skilled in the art upon referring to the drawings accompanyingr and forming a part of this specication in which:

Figure l isa'sidefview partlyain section of one f form of apparatus [of-this invention with certain :parts removed;

`@Figure -2 is a plan view of` the apparatus of Fig. 1;

`Figure 3 is an end elevational-view of the form rotating means-of `the apparatus of Figs. l and 2; ,-and,

Figure 4 is aplan-viewin section'of one of the forms illustrated' inFigsqland 2.

Infgeneral, the apparatus of this-invention inlcludes a receptacle R, ra liquidlatex bath B in :the receptacle, means M for circulating the bath,

`dipping forms'Rand means S for moving the forms sideways Aand simultaneously rotating the forms.

The illustrated-receptacleR Ais an open top metal 4tank having a bottom wall I0, side walls -I I,an end wall'I 2and another end wall I 3 which .defines a substantially circular chamber I4 having an open top and side portion. The receptacle R is provided #with a false bottomV I5 comprising a -metal plate secured to vthe side walls Il beltween the ends of--thefreceptacle by braces I6. The 7false bottom mI5 divides the receptacle into substantially equal upper andlower sections and 4defines with-the endiwall I2fa passage'for liquid between the-upper and lower sections. In the portion-of the false bottom-withinfchamber I4 and adjacentto wall I2,an aperture I'I is pro- .vided to permit liquid-to flow between the upper -and lower sections. l

'The-'end I2A of theireceptacleincludes a flange sail extending away from 'the Yreceptacleand up- .,wardly -at ran angle dof about vfive degrees. syntheticrrubber strip-2| vissecured r along the iupper part of wall IZ'and---within the receptacle -todene with wall I2 alcontinuous curved surface. The: upper edge ofY strip I2 isdisposed above 'the normal level of-latex in the-receptacle and -serves as a'resilientlbumper or 'bearing vedge for fthe forms Al when they move too far I'downwardly 4into thebath B.

Means M vcomprises atpaddle wheel vhaving a tshaft'z which is engaged for 4rotation with suitable'means (not shown), such as an electric rmotor. y'll'ie vshaft 25 'is disposed substantially vertically and the paddle wheel isdisposed within the chamber'and below the false bottom I5. The paddle wheeliis a conventional type and includes -a center sectionl 26, a plurality of arms 21 extending outwardly therefrom, and buckets or blades 28` vsecured to the outer ends of said arms.

`The forms F ai'e elongated, hollow, cylindrical i- 30 bottom I5.

open ends. The forms are disposed to roll on a rubber track 30 secured to the upper surface of flange 25 in such a manner that the lower sides of the form will dip into the liquid latex L. The

forms are disposed with their longitudinal axes substantially parallel to the upper surface of flange 25 and, therefore, at an angle approximat- "ing5 degrees to the surface of the liquid latex L. rIhe forms are maintained in this -position with respect to the track 25 by means S, the open end #portion of each form being gripped between the track 30 and means S.

"Means'S includes a revolving belt 35 to roll 1 :formsfF von'the track 25, a second revolving belt i361tofwhich'the forms are attached, a plurality of springs 31 bearing against the belt, a plate 38 retainingwthe-springs in position relative to the form, driving pulleys 39 around which the belt -is disposed, and mechanism such as electric\ motors (not shown) for driving the pulleys and V.belts V35 I-and-3(. The forms are secured tothe belt r3i5f-insu zhY manner Yas to v be rotatable relative :to vsaid belt.

.-As-willrbe apparent from the drawings, aplu- .25 rality of forms F may .befarranged with their longitudinal axes substantially parallel and with -za'djoining -forms'spaced close together. The belt r-3Ii-may be arranged 'tocarry'the forms through a plurality of stations along a closed path iniIO-cluding receptacle -R, as disclosed in-aforemenvtini'ied -United States Patent No. 2,128,827. The ftrack"30-may extend-beyond the ends of the receptacleto support. the'forms lin their course of `travel-between `and-,through the various stations,

.,l35..and theportions-,of the track adjacentto the lreceptacle aredisposed tocarry the forms upward @and over the-side wal-ls of -the receptacle.

V"In -the operationof the illustrated apparatus, withthe paddle disposed in position in the chamfrom the wheelvandoperatively engagingpaddle driving means, liquid latex lL is introduced into -receptacle'R until the receptacle'is substantially filled. A;plurality \of forms F are disposed as 545i1lustrated -upon track 30 in engagement with the `unsecured upper-endstrip 2| and rotatably attached to be1t36. 'The forms engaging the strip 2I'are gripped between track 30 and belt'35. In this-position the-forms? engaging strip ZI vare dis- 50..posedlwith their lower portions in contact with A455 of the formseF iri contactwith the liquid latex.

The `forms are-rotated by vmeans S andy the'paddle ywheel-is rotated, causing-circulation of the liquid .latex in a substantially horizontal direction toward-endV I2 of the receptacle but beneath false The liquid latex flows upwardly 4thi'ou'ghfthe. opening lbetween 'the end I2 andthe falsefbottom I5 -and inccontact Yfirst with the mid-section of'the-rotatingforms F, and thence along the forms,"finally/flowing in contact with .the submerged closed end portion of 'tl'ieforms Completing its circulationcyc1e, Vthe liquid latex flows into chamber I4, -downwardly 'through 'the vopenings'fl'l` and into vcontact with thebuokets 28 of'lth'e paddle wheel. A'The vform is simuly "taneously 1moved"horizontally and rotated rela- Mtive to vtlie-surface-ofthe liquid Vlatex by means rS. When the desired film has been 'developed upon'the forms, the 'forms are lifted from contactwwith the liquid `latex and moved lalong the glass elements; having closed, rounded ends,and75-pathrof beltl36vto yanother station for further processing. As one form is removed from the bath, another is introduced, making the operation a continuous one. In known manner, the forms may be cured or partly cured on the forms at various stations along the path of belt 3S, and the forms may be cleaned and washed and dried in preparation for a subsequent dipping operation in a repetition of the cycle.

Although I have specifically described only one form of this invention, I contemplate other forms which, as a matter of routine, Will occur to those skilled in the art. For instance, instead of the strip 2| being disposed as shown and normally out of contact with the forms F, said strip might be disposed to constantly bear against and support forms F as they pass along the receptacle in contact with the dipping bath. I consider such other iorms as Within the spirit of this invention and within the scope oi the appended claims. l

Having thus described the .present invention so that those skilled in the art may be able to understand and practice the same, I state that what I desire to secure by Letters Patent is defined in what is claimed.

What is claimed is:

1. The method of making a dipped article which comprises the steps of moving sideways a substantially horizontally disposed revolving form supported at one end, and moving a lm forming liquid lengthwise of the lform toward its free end while maintaining the form in substantially horizontal position.

2. The method of making -a thin rubber article which comprises the steps of moving sideways a substantially horizontally disposed revolving form supported at one end, and moving liquid latex lengthwise of the form toward its free end while maintaining the form in substantially horizontal position.

3. The method of making a thin rubber article which comprises the steps of moving sideways a substantially horizontally disposed revolving form supported at one end, moving liquid latex lengthwise of the form toward its free end while maintaining the form in substantially horizontal position and subjecting latex lm deposited on said form to drying conditions.

4. Apparatus for making deposited articles comprising a receptacle for film forming liquid, an elongated form disposed substantially horizontally with its under portion partially immersed in said liquid, means for moving said form substantially horizontally across the receptacle while so disposed, means for rotating said form while so moving, and mechanical means in the liquid for moving said liquid length- Wise of said form toward its free end while the form is being so moved and rotated.

5. Apparatus for making thin rubber articles comprising a receptacle for liquid latex, a cylindrical form supported near one end and maintained at a slight angle to the surface of said liquid latex with its runder portion and free end partially immersed in said liquid latex, means for moving said form substantially sidewise lacross the receptacle while so positioned, means for rotating said form while so moving, and mechanical means in the latex for moving said latex lengthwise of said form towards its free ntddwhile the form is being so moved and ro- 6. Apparatus lfor making thin rubber articles comprising a receptacle for liquid latex, a cylindrical form supported near one end and maintained at a slight angle to the surface of said liquid latex with its under portion and free end partially immersed in said liquid latex, means for moving said form substantially sidewise across the receptacle while so positioned, means for rotating said form while so moving, and mechanical means including a paddle wheel in the latex for moving said latex lengthwise of said form toward its free end while the form is being so moved and rotated.

7. The method of making a thin rubber arf' ticle which comprises the steps of moving sideways a substantially horizontally disposed revolving form supported at one end, contacting the form with a liquid latex dipping bath, holding a part of the free end of the form above the surface of said bath throughout the period that the form and bath are in contact, and moving the bath lengthwise of the form and toward its free end.

8. Apparatus for making thin rubber articles comprising a receptacle for liquid latex, a cylindrical form supported near one end and maintained at a slight angle to the surface of said liquid latex with a part of its free end above said surface and another part of said end immersed in the liquid latex, means for moving said form substantially sidewise across the receptacle while so positioned, means for rotating said form while so moving, and mechanical means in the latex for moving said latex lengthwise of said form toward its free end while the form is being so moved and rotated.

9. The method of making a dipped article which comprises the steps of moving sidewise a form supported at one end and comprising an elongated cylindrical portion and a semispherical free end portion, contacting only the lower part of said semi-spherical end and the under side of the said cylindrical portion of the form for the length of the desired article with a nlm-forming liquid, and rotating said form while maintaining said limited contact with the liquid.

10. The method of making a dipped article which comprises the steps of moving sidewise a form supported at one end and comprising an elongated cylindrical portion and a semi-spherical free end portion, contacting only the lower part of said semi-spherical end and the under side of the said cylindrical portion of the form for the length of the desired article with a nlmforming liquid, rotating Isaid form while maintaining said limited contact with the liquid, and flowing the liquid along the forms from their supported ends to their free ends while they are being moved sidewise and rotated as specied.

EDWARD S. KILLIAN.

REFERENCES CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS Number Name Date 2,299,269 Gammeter Oct. 20, 1942 2,353,256 Maywald July 11, 1944

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