US2926628A - Roll type glue spreaders, surface coaters, and the like - Google Patents

Description

March 1, 1960 R, s, BLACK Erm.-

ROLL TYPE GLUE SPREADERS, SURFACE COATERS. AND THE LIKE Filed Sept. 7, 1956 InvenTors: 'abe VT 5. Back 8f LTcxmfz 5.C roU roll.

United States latent O 11 claims., (cl. 11s-244) This invention relates to that general type of glue spreader, or surface coater, disclosed in Letters Patent of the United States No. 2,326,429, issued AugustlO, 1943 on the application of lohn E. Black and Robert S. Black, but as will hereinafter appear, certain features of novelty herein disclosed are not limited in their application to devices of the general type of that earlier patent and are yof more general application. However, for purposes of illustration of `the present improvements we will hereinafter make reference to that earlier patent. In` so doing, however, we do not intend to limit the protection to be lafforded by the present application and the Letters Patent `to be issued thereon, except as we may do so in the claims to follow.

Generally speaking the presently disclosed device infcludes two main rolls" which are journalled one above 4the other in a common vertical plane and with their respective axes extending horizontally, `together with means to apply to the surfaces of such rolls the desired adhesive in liquid form. When both surfaces of a sheet areV tobe coated such adhesive is applied by maintaining both of the rolls coated with the adhesive; when only one surface of the sheet is to be coated only one of the rolls is maintained coated with the adhesive, generally the upper The sheet is passed horizontally between the two rolls, for which purpose such rolls are setto a clearance between them proper to pass the thicknessof the sheet then being coated. Usually a resilient device is provided in the roll supporting assembly to permit one of lthe rolls to shift slightly away from the other under resilient force,

to take care of slight inequalities in sheet thickness `and for other purposes; but the roll supporting assembly also includes means to enable the operator to accurately predetermine and maintain the normal separation between the rolls at that value which will properly receive and `treat the thickness or" sheets being treated. Such general 'types of device are disclosed in that earlier patent,g'and are also disclosed in the devices herein disclosed. f

' In order to provide on the main roll or rolls a film of adhesive to be applied to the sheet surface or surfaces suitable means are provided'to `produce this function. r

One such means comprises a doctor roll for eachrmain roll, suitably journalledwith its axis parallel to that` of its main roll, and in substantial horizontal alignment therewith. Each such doctor roll thus provides in conjunction 'with its main roll a V-shaped trough or crotch, and suit- V able end plates `are provided in contact with theends of the pair of rolls at the location of such trough or crotch to enclose the ends thereof, and thus provide a pocket within which the adhesive is retained and from which itis fed to the surface of the main roll. By adjusting such The thickness of such film of adhesive (usualiCe and acting to shift the axis of the doctor roll towards' of away from the axis of the main roll. Such devices are also shown in the aforesaid Letters PatentrNo. 2,326,429,

and means to effect such adjustments are also disclosed in the present application.

In order to `better `control the thickness of the film of adhesive which is applied to the surface ofthe sheet being coated, and to ensure a more uniform thickness of such film over the entire surface being coated., it has been found desirable to provide the surfaces of the main rolls with rather fine encircling grooves, eithercircular and self-contained, or of spiral form. These grooves, when provided, arev of s mall dimensions both as to pitchbetween successive grooves, and as to their depth. Such grooves may be of the order of 22 per inch axially of the roll, and depth of the order of 0.025 inch. Sometimes fsuch grooves are of V-shape with one side wall of the V extending radially of the roll, or normal to its axis', and the other side wall of such V of suticient angle to the plane normal to the rolls axis to provide the desired cross-section of the groove. Sometimes such grooves are formed Vso that neither wall of the groove lies normal to the rolls axis but both of the walls of the groove lie within planes or surfaces (conical in form) which are Vat acute angles to the axis of the roll. In such case an undercut form of groove is produced. Both forms of such grooved main rolls are shownV in Letters Patent of the United States No. 2,343,363, issued March 7, 1944 on the application of John E. Black and Robert S. Black.

In order to permit slight deformations of the surface of the main roll as it exertspressure against the surface of the sheet being coated the peripheral surface of the main roll is generally formed of yieldable andresilient material such as rubber, neop-rene or like materials. Rolls of such type are also shown in the aforesaid Letters Patent of the United States, and said Letters Patent also shows such surfaced rolls as provided with grooves of both of the forms previously referred to herein. It is here noted, however, that the surfacing of rubber, neo prene, or other yieldable material as disclosed in that earlier patent is homogeneous through its entire thickness from its outer perimeter to the supporting tube or hub on which such surface of yieldable material is mounted. Thus the hardness and characteristics of such surface coating are substantially uniform for the entire radial dimension of such surfacing. It is here noted, also, that such surface coating is subjected to wear during usage, thus changing its overall diameter and the 'contour-sof the grooves. `To meet this condition it is desirable to use, for such surface coating, a yieldable material of considerable toughness combined with that degree of resiliency needed -to meet the operating conditions. Those operating conditions include both the need of allowing for slight inequalities in the thicknesses `of the sheets at different locationsas such sheets ride between the two main rolls, as well as permitting the grooves lto deform under surface pressure exerted radially against the main rolls by the Asheet being treated so as to -expel the desired amount of adhesive onto each uni-t area ofthe surface being coated.

Thus, in that earlier patent it was disclosed that yieldable `material of the general hardness of the order of 210 toV '60 on th scale of the Shore durometer was considered satisfactoryl l Now, evidently the deformation of the surface of the surfacing is formed, the radial dimension ofthatsurfacing, the lform and size of the grooves, their spacing,anc l sheet thickness at different areas thereof will necessarily produce corresponding variations in the deformation of the main rolls surface since the parts are under opposing pressure conditions. These deformations of lthe main roll-s surface are of two kinds; First, they include deformations ofthe ridges between the' successive grooves of the roll surface, and Second, they include bodily shift of the ridges radially inwards towards the axis of rotavtion. (The latter deformations can be produced only at 'the expense of the former deformations, since the de- "forming pressure is exerted radially inward from the elemental areas of roll rsurface which are in cont-act with Lthe surface of the sheet being treated, and these elemental areas which first receive the pressure Vfrom the sheet beingtreated are the outeredges of the ridges between the grooves. When the entire thickness radially ofthe yieldable surfacing is homogeneous, as disclosed in that earlier patent, is it evident that by .far the greater portion of the yield produced by the pressure of lthe sheet being treated will be taken up by the ridges between the grooves, since the body .of such ridgestper unit radial dimension) is fmuch smaller than the body of thesup- .porting non-ridged section .of the surfacing of lthe yield- .able material. in other words, the pressure exerted per .square inch section of the ridges is much vgreater than .thepressure exerted per square linch section of that portion of material radially inwards from the ridges. Thus, for. a given pressure exerted against the perimeter of the .so-formedroll, most of the deformation will occur with- .in the radial dimensions of vthe ridges between ,the grooves, and only a very small deformation radially will `occur inthat 'body o-f yieldable material located-radially .inwards from the ridges themselves.

LVariations `'in the amounts of deformations of the .ridges will necessarily result in variations of amount .of adhesiveexpelled over corresponding areas of thev main rolls, :and with corresponding `variations in the thickness .of .the l-m of adhesivefplanted on the various elemental areas of the sheet surface being coated. Thus, it now becomes evident that variations in the sheet thickness vmust necessarily result in variations in the thicknessof y.the film planted'on the surface of the sheet at corre ...sponding locations. Thus a serious disadvantage in .the .uniformity of .treatment of the sheets surface occurs, and the uniformity of application of the adhesive 4to .all areas of the sheets `surface is destroyed. .Since itis ya desirable Quality of the coating Vmachine to ensure .substantial uniformity of application of thetadhesive to-'all lareas of .the sheetssurface it is .desirable to makempro 7^#visionto .meet and counteractthe underlying .structural 'features ofthe main rolls which features have hereto ffore .produced this objectionable condition. It Yis Y the ,prime Vobject of the present .invention :to provide inathe vmain rolls :further kstructural features which willfensure y'attainment of this desirable result.

'-'We :have provided andshall disclose ,herein .a main roll constructionin tsuchgroll .type glue .spreaders and @surfacecoaters Awherein `we provide Ya1rather .thin :surface .of tough, somewhat hard .resilient 4yieldable material, fcapableof resisting the wearnecessarily attendant :on .the -nperationjiofgsuch devices, .and provided lwith .ag-groomed :dged surface .capable of ensuring ,the expulsion 'of tithe desired l.amount of adhesiveby .deformationxofisuch .zridges, .together with .a supporting ybase of rather fsoft, preferably'spongy material of yicldable material .of Ielaslfilature, Ksuch v.soft .base being such *as to Y yield :sufstcientlyzto take care of .mostof .the inequalities .in thick- .guess .of fthesheet .being treated, :with .a yminimum varia :fion-:in `the ideformationsof .the.;ridges at the v4surface .of lthezrroll. ilhus we .have comhinedgthe .function :of exfgilsn fa :desired tamount .of adhesive hy slight Aradial .fde'formati'on fof .the rolls surface ridges, .togethervwith provision rto .take fcare 'of the inequalities. yin :sheet thickfbyf=votying mums -of yield of .the soft-ibase.

so .embodying .the features :of the Vpresent invention, the {uppermne-.hlf Lof such .tgure being in vertical section, ,and intermediatesections -o'f the roll beingleft .out `to The functional operation of the foregoing combination maybe likened to an elastic unit formed of arather stiff spring and a softer spring in series so that the defoirning force is exerted through both sections. Such an arrangement when subjected to a deforming force will produce a slight deformation of the `stiff spring section, and a much greater deformation of the softer spring section, so that slight variations of deforming force will act principally to produce changes vin the deformation of the softer section, and comparatively insignificant changes in the deformation of the stiff section. By way of illustration only, and not as a matter of limitation we have successfully used main rolls 'having surface sections of tough, resilient long wearing material, of a hardness of substantially 65 point durometer on the Shore A scale, such material conveniently being rubber or neoprene, together with a base section, preferablyV very spongy and of a softness of substantially 12-15 point durometergon the Shore A, scale. With such a combination, and using a surface section of substantially inch radial dimension, and a base section of substantially l inch radial dimension all of the desirable qualities hereinbefore explained have been attained, and the objectionable qualities eliminated. The base section may conveniently be vformed of sponge` rubber, neoprene, or other resilient material. Taking account of the greater radial dimension of the soft .base `and its greater softness specification, and themuch smaller radialV dimension vof the hard outer section and vits much greater hardness of lesser softness, itis evident that by far the greater amount of the deformation changes produced by slight inequalitles in the thickness of the sheet being coated will .be taken up by the Vbase section, Vand substantially without change inthe deformations of the ridges between the grooves of the contacting surface. vThus a substantially .uniform l'rate of delivery of the adhesive to the surface being treated will'be ensured, ensuring substantially equal amounts of vadhesive to all equal areas of the treated surface, notwithstanding inequalities in the .thickness of the Sheet being treated, or other like irregularities.

Other objects and uses of the invention will appear `from la detailed description of the same, which consists .in the features of construction and combinations of parts hereinafter described and claimed.

In the drawing:

Figure .1 shows, schematically, a surface. coater em .bodying the .features of the present invention, and in "cluding two main rolls in vertical alignment, together with corresponding doctor rolls located 4in substantial horizontalalignment with their main rolls, together with .spring vyieldablemeans urging the upper main roll .down-y Wardly, `and :horizontally :adjustable doctor rolls which may be :adjusted with respect to their companion main irolls .to'providexthe desired small clearances betweenthe main and doctor rolls, .and also .including means to adjust the elevationofsthe lower main roll to provide for accom vrmodation ofsheetsfof various thicknesses, but with slight .vertical adjustability lof .the `upper main roll corresponds .ing to 'sheets of '.dcviationfrom intended thicknesses, etc.; .figur-e2 .shows .a longitudinal view of a main roll l the grooves :zare not undercut .but are `provided with vplanar fsurfacesion one -side of each ridge, such planar surfaces lbeingnormal tothe axis of .rotation of the rroll. .In ,Figure l .the upper :and lower .main rolls .are .shown at 11 and 12, respectively, and the companion doctor rolls are shown at 13 and 14, respectively. The upper main roll is shown schematically as provided with the upwardly extending vertical stem 15 carrying one of the journals for such roll, shown at 16. The other journal and stem are not Ishown inFigure l as they` have been cut away in such figure. A spring 17 urges the stem 15 downwardly to produce a pressure of the upper mainroll against the sheet 18 being coated, such sheet travelling towards the left as shown in Figure 1. The journal 19 is shown for one end of the lower main roll, being connected to a stem 20. The journal for the near endof such roll is not shown in Figure 1 as it too has been cut away in such figure, and this is also true of the correspondingdownwardly extending stem. By adjusting the stems for .the lower rollfs journals the elevation of such lower roll may be adjusted to meet requirements of various specified thicknesses of sheet stock being fed between the wo rolls. To effect such adjustments such lower stem 201 is shown as being threaded to receive an adjusting screw element. The two doctor rolls are shown as provided with the journals 21 and 22, respectively, each such journal being provided with a corresponding horizontally extending stern 23 or 24 Vas the case may be, it being understood that the near journals and stems have been cut away in Figure` l. These stems 23 and 24 are shown as being threaded to receive adjusting elements whereby the doctor rolls may be adjusted towards and away from their companion main rolls to adjust the clearances 25 and 26 between such doctor rolls and their companion main rolls. Pockets or crotches are thus provided between the doctor and main rolls, the ends whereof are closed by plates (not shown) so that adhesive or other liquid material to be applied to the surfaces of the sheet 18 may be carried by the main rolls to the sheet areas being treated, the amount or thickness of the film of such adhesive which will be planted on the surface of the sheet being thus adjustable by the setting of the doctor rolls. Such arrangements are disclosed in the aforesaid Letters Patent No. 2,326,429, and here shown for purposes of illustration only, and as showing the relationship of various features of the present invention to the functions and operations which are produced by the complete machine.

Reference is now had to Figure 2 which shows the detailed construction of one of the main rolls.` It comprises the two end blocks 27 and 28 which are provided with the outwardly extending shaft extensions 29 and 30, respectively. These shaft extensions are provided with suitable journal receiving sections 31 and 32, which receive journals such as those shown at 16 and 19 in Figure l. Blocks 33 and 34 are secured to the blocks 27 and 28, preferably by seating such blocks onto the inner end portions of the blocks 27 and 28, respectively, and welding the parts together as indicated in Figure 2. The blocks 33 and 34 are conveniently shouldered as shown at 35 and 36 to receive the ends of a tube 37 which constitutes the unyieldable element on which the yieldable elements of the roll are mounted. Con veniently the proximate portions of the tube ends and the blocks 33 and 34 are kerfed as shown at 38 and 39 to enable the tube ends to be welded to said blocks, thus providing a strong rigid support for the yieldable ele ments of the roll.

The yieldable section of the roll is tubular in form, comprising the inner rather thin tubular sheet 40, of metal or rather hard rubber or the like, on which is directly mounted the cylindrical inner soft resilient yieldable section 41. Onto this soft inner section 41 there is mounted the outer harder cylindrical section 42 also of yieldable, resilient material, such as rubber, neoprene, or other like material. The roll illustrated in Figure 2 has an outside diameter of substantially A11% inches. The thickness of the outer section 42 then has a value of substantially t inch, and the thickness Yof the inner section a value f substantially l inch. These two sections may be cemented or otherwise secured together, or the outer sectionmay be slightly expanded in diameter and then slipped onto the innei` section, and then allowed to contract into firm engagement with such inner' section.` In operation the two sections are in sufficiently firn engagement, the one with the other that they must rotate at all times exactly as a unit'. Preferablythe outer perimeters of the blocks 33 and 34 are carried outwardly as flanges 43 and 44, respective.-l ly to overlie and protect the ends of the yieldable `sections; but it is noted` that `such flanges are of slightly smaller external or outside diameters than the outer surfaces of the section 42 so that such anges'43 and 44 do not come in contact with 13 or 14 or shall not come into direct engagement with the surface of the sheet being coated in case such sheet should inadvertently over run the end or ends of the roll.

Reference to Figures 3 and 4 will show two alternative forms of grooving and ridging the outer surface of the yieldable section 42. Duc to the fact that the grooves shown in Figures 3 and 4 have a depth of only the order of 0.025 inch they cannot be conveniently shown in the section of Figure 2, but they are indicated by the annular lining of the lower, unsectioned one-half of Figure 2. In the form shown in Figure 3 the grooves 45 are shown as being undercut at their left-hand faces 46 by forming such faces at an acute angle to a plane normal to the axis of roll rotation; and the right-hand faces 47 are then formed at a greater acute angle to such plane normal to the axis of rotation, the outer encircling annularqsurface 48 lying within the perimeter of the roll. The surfaces 48 are those which cornerinto direct contact with the sheet surfaces being treated. Upon exerting directly inward radial pressure against such outer surfaces 48 the ridges which they terminatewill be laterally deformed as shown by the dotted lines in Figure 3, thus expelling some of the adhesive contained in the groove since the volume of such groove will thereby be reduced. In the modified form of ygroove shown in Figure 4 the left-hand faces 46a of the ridges are formed in planes normal to the axis of rotation instead of at acute angles as in the former showing. However, generally speaking both forms of groove and ridge are subject to the same laws of operation and analysis.

Now the hardness (or lack of softness) of .the outer section 42 as compared to the lsection 41 is such that when a deforming force has been exerted on the outer surfaces 48 to deform the ridges at any extent, inward pressure is also being developed against the soft yinner section 41. Thus such section will also yield inwardly, so that a less deformation of the ridges will occur than would be the case with an inner section of material substantially of the same hardness (or lack of softness) as the outer section 42. Accordingly, less adhesive will be expelled from the adjacent grooves than would be the case with a harder inner section. The hardnesses of the two sections can be made such in relation to each other that when a certain pressure or force has been developed against the outer ridge surfaces `48 with corresponding expulsion of desired amount of adhesive, further force developed against such ridges will cause inward deformation of the inner section as fast as the outer surface 48 is forced inward, so that a limit is then reached as to the amount of adhesive which may be expelled from the groove. Thus, excessive pressures developed against the surfaces 48 will not thereafter change Ithe amount of adhesive which will be expelled. This function is directly related to the fact that the outer section 42 is formed of much harder yieldable and resilient material than the inner section 41.

We claim:

l. In a roll type surface coater, the combination of a pair of main rolls, means to journal said rolls for rotation on parallelA .axes and with the proximate surface portions of the rolls separated from Veach other a distanceto accommodate the thickness oa sheet of stock to be surface coated, means to rotate `said rolls in opposite directions, at least one of .such main rolls comprising a stiff cylindrical base, a tubular section Aof soft, yieldable, resilient material of substantially uniform radial thickness of the order of one inch mountedon said cylindrical base, and a tubular' section of tough, resilient material of substantially .uniform radial thickness of the orderof inch mounted on said soft yieldable resilient .material section, together with means to supply a controlled thickness lm of coating material to the surface of said. main roll the radial dimension of said tubularsection of tough resilient material being not over substantially one-half the radial dimension of said .tubular section of soft, yieldable resilient material.

2. Means :as defined in claim 1, wherein, said soft, yieldable, resilient material section is composed of rubberlike material.

-3. Means Xas defined in claim l, wherein said soit, yieldable, resilient material section is of spongy formation.

V4. `Means as dened in claim 3, wherein said soft, yieldable, resilient spongy material section is composed of rubb er-like material.

5. Means as defined in claim l, wherein lsaid tough,

.resilient material'seotion is composed of rubber-Elternaterial.

6. Means as defined lin claim `l, wherein said soft, yieldable, resilient material section has -a hardness of sub.-

stantially 12.-. 15 point durometer on `the .Shore A .scale of hardness. y

7. Meansas dened in claim 1, wherein said'rtough, resilient :material section has a hardness of substantially '6 5 point durometer on the Shore A scale of hardness.. 8. yMeans as defined Ain claim 7, wherein said soft, Vy:ieldab.le, resilient material section has a hardness .ofsubstantially 12- 15 point durorneter on the Shore A scale ofrhardness.

9. :In .a `roll type surface coater, the. combination of a pair of main rolls, means to journal said rolls lfor rotation on parallel axes and with -the proximate surface portions of the rolls separated from each other a distance to accommodate the thickness of a sheet of stock to. be surface coated, means to rotate said rolls in opposite directions, at least one of such main rolls comprising la stiff cylindrical base, a tubular section of soft, yieldable, resilient mate-rial of substantially uniform radial thickness mounted on said cylindrical base, and a tubular section ojf tough, resilient material of substantially uniormradial thickness mounted on VVsaid soft yieldable resilient material section, together with means to supply a controlled :thickness iilrn of coating material to the surafce of said main roll, and a series of circular Vgrooves in the surface of said tough, resilient tubular section, .with circular ridges between said grooves, the outer edge portions of such ridges comprising sheet stock surface engaging areas of said tough, resilient tubular section the radial dimension of said tubular section of tough, resilient material including the circular ridges thereof being not over substantially one-half the radial `dimension of said tubular section of soft, yieldable resilient material.`

l0. .Means as defined in claim 9, wherein the opposite faces .of each .ridge are Aformed at different angles with respect `to the axis of rotation of said main roll.

All. vMeans as delined in claim 10, wherein the ldepths of said grooves radially are substantially one fifteenth of theradial thickness of `said tough, resilient tubular section.

'References Cited in the le of this patent UNITED STATES PATENTS l ,"Black et al. Mar. 7, 1944

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