Патент USA US2405235код для вставки
Aug. , 19%. ' _ B. M. RANDALL 1 UNDERLAY FOR FLOOR COVERINGS ' Filed Dec. ' 5, 22 ‘ l? 19,42 l6 < ' l((((ll((((((((l(l((((((((((((((M m 22 ' .' " . ' Iv@m?@r, Basra-‘MM mg. Bab“ l 2,405,235 Patented Aug. 6, 1946 UNITED STATES PATENT OFFICE Boardman M. Randall, Portsmouth, N. H., assign or to TekWood, 1110., Lakeport, N. H., a corpo ration of New Hampshire Application December '5, 1942, Serial No. 468,009’ 7 Claims. (Cl. 154-453) 1 This invention relates to an improved composite board which has particular utility as an underlay for linoleums and the like resilient or compres sible floor coverings although it is suitable also for various other structural purposes as, for in 2 having surfaces protecting the plywood core- from detrimental attack by moisture. It is a further object of the present invention to provide an underlay which has stiffness and resiliency capable of permanently bridging de stance, packing crates, walls and the like. pressions and cracks in a sub-floor and which is Any use of a stiff underlay for ?oor coverings of the nature of linoleum usually presupposes a ous barrier sheets which constitute also a means protected against warping by moisture impervi permitting differential expansion and contraction sub-?oor having irregularities of surface, joints. etc., which would be impressed in the linoleum ll) without danger of breaking the cement bond be tween the ?oor covering and the underlay or other floor covering and thereby be made visi Another object is to combine these mentioned ble at the surface of the covering if the latter qualities of stiffness and resiliency in an underlay with or without a felt backing were laid directly ‘whose over-all thickness dimension is commer on the sub-?oor. Thus, any effective underlay must have sti?ness and resiliency capable of per 15 cially acceptable. manently bridging depressions and cracks in the .A further object of the invention is the provi sion of a plywood underlay as above described sub-?oor, and provision also must be made to having a protective surface thereof which func prevent warping of the underlay and to permit tions asthe usual lining felt to which. the ?oor relative lateral shifting of the underlay and the floor covering to take care of differential expan 20 covering is adhesively af?xed, thereby eliminating the necessity for a special lining felt. sions and contractions which otherwise would A feature of the invention resides in utilizing break the bond between the linoleum and the a moisture impervious substance. which continues underlay. inde?nitely rather tacky, and a water insoluble I am aware that it has been proposed hereto fore to use plywood as an underlay for ?oor cov-_ 25 substance which sets to relative hardness and provides a strong and permanent bond. in the erings; and also laminated ?bre board structures. midst of the underlay as well as constituting Actual experience has shown, however, that the with the tacky substance a de?nite barrier prior plywood underlays have been open to attack against passage of moisture. by moisture with consequent warping and fre It is, moreover, an object of the invention to quent breaking of the cement bond between the generally improve composite board structures linoleum and the underlay and also of the bond and particularly such structures used as under between the plies of the underlay. This produces lays for ?oor coverings. , bulging or cracking of the ?oor covering which, The mentioned objects and results may be at aside from its unsightly appearance, causes un tained by employing a stiff sheet of wood as a even wear at the affected regions. The prior core for the underlay, which preferably will be laminated ?bre board structures have not been satisfactory because they are compressible and gradually become molded to the contour of the plywood, and applying to each face of the wood core a paper sheet impregnated with a moisture impervious substance that, for at least one paper ?oor very soon become visible at the surface of ~10 sheet has the further characteristic that it com tinues inde?nitely rather tacky. the ?oor covering. Between each sheet barrier and the wood core The plywood underlay heretofore proposed has a thin ?lm of water insoluble adhesive constitutes been a plywood board of the order of half an a bond between the wood core and the barrier inch or thereabouts in thickness and comprised sheet and, in conjunction with the barrier sheets, of ?ve or more plies, presumably in an attempt effectively insulates the wood core against mois to minimize the action of moisture thereon. A ture. Preferably the Water insoluble ?lm is one thick underlay is objectionable as it raises the having strong aflinity for both the wood and the surface of the covering to such an extent, fre impregnated paper ?bres but which does not quently, as to interfere with the proper operation greatly penetrate beyond the surface of the im of doors and is otherwise objectionable. Hence, pregnated paper. Thus, when the water insol-_ an object of the present invention is the provision uble ?lm sets to hardness the ?bres‘ in the midst of a thin plywood underlay that is rigid to resist of the paper sheet continue capable of slip rela deformation under the weight of a person and sub -floor, and irregularities and cracks in the sub resilient to spring back to its origina1 ?at condi tion when relieved of 'an unusual pressure and tive to each other, thereby to permit differential expansion and contractionas between the‘ floor 3 2,405,235 covering and the underlay without danger of breaking the bond between these two. The paper barrier sheets preferably are rela tively thin. They may be, for example, of felt ed ?bre variety, as paper felt, felted under con siderable pressure so that the barrier sheets on two faces, of the wood core do not detrimentally 4 eral stresses at the regions of attachment. Thisi permissible shearing of the paper barrier relieves‘ the cement bond between the ?oor covering and‘: the underlay of the stresses which otherwise‘ might break the bond. Any suitable paper may‘ be employed for the barrier sheets 22, but I have found a paper felt to have desirable character~ istios of strength and ability to absorb substan— add to the over-all thickness of the underlay. Yet the impregnated felted ?bre structure of tial amounts of the asphalt or other moisture im each sheet and the water insoluble bonding ?lm '10 pervious agent. The paper sheets 22 may be rela effectively resist the passage of moisture and tively thin, for example, 16 thousandths of an permit relative lateral shifting of mid-?bres for‘ inch in thickness, thus adding only slightly to the purpose above explained. the overall thickness of the underlay. Yet these In the accompanying drawing, sheets, treated as above, e?ectively combine with Fig. 1 is a vertical sectional view through a 15 the urea resin glue to insulate the wood core floor having my improved underlay thereon and having a linoleum floor covering laid upon the against absorption of moisture from the water soluble cement, usually of lignin variety, em and , , ' ‘ ployed for attaching the floor covering to the Fig. 2 is a perspective view of a fragment of a underlay, and from atmosphere. Also sheets of‘ corner portion of a sheet of the improved under 20 this mentioned thinness can effectively perform lay on an enlarged scale, with corner portions the function of providing ?exibility between the underlay; of the barrier sheets pulled away from the core. linoleum and the underlay which accommodates Referring to the drawing, Fig. 1 shows a rough di?erential expansion and contraction as be under ?ooring Ii! on the usualjoists l2, and a tween the ?oor covering and the underlay. top ?ooring .Monthe under floor. As illustrat The term “sub-?oor” is employed herein in the ed, worn depressions l5 and cracks IT between broad sense of meaning any rough and irregular the ?oor boards are exaggerated somewhat to floor or other support upon which the composite board structure may be spread. emphasize the bridging ,characteristics of the improved underlay l6, which is shown laid over In use, my improved underlay will be arranged the irregular surface of the top ?oor 14. A ?oor 30 as illustrated in Fig. 1, and may if desired be covering [8 is laid upon the underlay. cemented to the sub-?oor, although preferably it - Referring to Fig. 2, the underlay comprises a will be attached by nails or drive screws not stiff and resilient wood core 20 preferably com-' shown. The underlay is applied to the ?oor pref~ posed of three plies of wood veneer which in a erably with the parallel grains of more than one practical embodiment of the invention each may 35 ply crossing the cracks of the ?oor. The underlay have thickness approximating 1/20 of an inch. as is seen in Fig. 1 bridges any depressions and They may bethicker or thinner as desired and cracks in the sub-?oor but due to its characteris are combined with crossed grains. The num tic resiliency it may be temporarily depressed into ber of plies may be varied to suit speci?c pur such a depressionbut it will spring back as soon poses. The veneers preferably although not nec as the depressing force is removed. The barrier essarily are from deciduous woods, as beech, sheet 22 on the underside of the underlay com birch, for instance, which have close grain and bined with the Water insoluble ?lm of glue 3!] are strong and permit the‘ use of a thinner core between it and the wood core effectively insulates than one made from weaker wood of a more the core againstfmoisture which may come up open grain. The barrier sheets 22 on opposite 45 through the floor cracks or otherwise ?nd its way faces of the plywood preferably are felted paper between the ?oor and the underlay, The upper sheets impregnated rather generously with a impregnated barrier sheet 22 coacting with its suitable 'water impervious substance such, for associated ?lm of water insoluble glue 3!! similarly example, as asphalt. The asphalt or other sub-' effectively insulates the core at the upper side stance preferably will be of a consistency and against moisture from the linoleum cement and from atmosphere. . type which can readily penetrate the felted paper sheet as a liquid and which will continue inde? The underlay ordinarily will be'supplied com_ nitely to have a rather tacky character and feel. mercially in rectangular sections of size to‘ be In the drawing, Fig. 2, the water impervious conveniently transported and handled, such as 4: substance is indicated at 26 by the irregular dots foot square sections or larger or smaller. dispersed among the promiscuous lines 28 which The plies of the core preferably are bonded represent the feltecl?bre of the paper. one to another by a water insoluble adhesive or According to the invention, said barrier sheets glue as, for instance, a urea resin, which exists of paper 22 are strongly bonded to the plywood as a water impenetrable ?lm between each pair core by a water insoluble ?lm of glue, indicated of plies. in Fig. 2 by the stippling 3B. This glue 30 may While the barrier sheets are above described be of any suitable kind but I have found that urea as identical, this need not be the case as the resin glue has a satisfactorily strong amnity for ' under barrier sheet need not be a paper felt but both the woodgandr the impregnated paper and can be harder, as a kraft or other harder sheet that it does not greatly penetrate either the sur 65 and can be rendered water impermeable by a face of the wood or go deeply into the structure harder asphalt having a higher melting point, as of the paper under the combining pressure and its main function is to prevent the wood core the heat required for setting the resin. In the from being subject to moisture that may be pres case of the paper barrier sheets I consider this ent in the air in contact with the lower surface important in that it leaves the matted ?bres in 70 of the underlay, as when the underlay overlies a the midst of the paper sheet restrained against cellar, for instance. 7 > lateral relative movement only by the asphalt which is not set-to hardness andthus the paper can to a needed extent shear laterally at'this The underlay is made by combining. the various woodveneer plies and the asphalt-impregnated ‘facing sheets with‘ liquid bonding ?lms of the mid region as differential expansion imposes lat 75 thermo-setting resin'in a ?at plate press under 2,405,235 5 6 suitable pressure, as two hundred pounds per square inch and, where the wood plies are bal~ anced, as by having an odd multiple of plies, at a temperature suf?cient to set the resin adhesive or to convert it to its infusible form. The tem perature may be two hundred ?fty degrees Fahr paper and strongly adhering to both the wood and the surface ?bres of the barrier sheet. 3. A composite board comprising a core sheet of a plurality of plies of wood veneer combined on each side of the core with a barrier sheet of thin felted paper impregnated with asphalt and a water insoluble thermosetting resin ?lm having af?nity for both the wood and the asphalt-im effect the conversion. At this temperature the pregnated paper and strongly adhering to both asphalt in the facing paper sheets is liquid which prevents the liquid resin from penetrating the 10 the wood surface and the surface ?bres of the barrier sheet. paper sheets to any deleterious extent. 4. A composite board comprising a core sheet When the plies are unbalanced, that is, there enheit, or thereabout, maintained long enough to of a plurality of plies of wood veneer combined on each side of the core with a barrier sheet of pressing, in a hot room at say around one hundred 15 relatively thin felted paper impregnated with asphalt and a ?lm of urea resin glue strongly ad twenty degrees Fahrenheit for a sufficient time hering to both the wood surface and the surface as six to twelve hours to set the adhesive, a suit able catalyst being used with the adhesive to ob ?bres of the barrier sheet. 5. A composite board comprising a sheet ele tain setting or polymerization of the resin with in this temperature and time to produce a ?at 20 ment of wood combined with a facing barrier sheet of felted paper thinner than the wood sheet composite board. and impregnated with asphalt, and a ?lm of urea I claim: is an even multiple of plies, it may sometimes be preferable to place the composite board, after 1. An underlay for resilient ?oor coverings resin glue strongly adhering to both the wood sur comprising a thin wood core composed of three face and the surface ?bres of the barrier sheet. 6. A composite board comprising a sheet ele plies of thin wood veneer combined with a water 25 insoluble glue and with crossed grains forming ment of wood faced on at least one side with a a composite board balanced to resist warping in sheet of ?brous material thinner than the wood sheet and permeated by a moisture impervious any direction and rigid to resist deformation due substance having the characteristics of asphalt to normal pressures thereupon and resilient to spring back upon removal of abnormal pressures 30 including the character that it continues tacky at the exposed surface of the facing sheet. thereupon, a lining felt bonded to a face of said 7. An underlay for ?oor coverings comprising core by a wtaer impermeable adhesive and said a wood core, a felted ?brous facing sheet on the felt being permeated with a water insoluble sub core, a thermosetting adhesive bonding the wood stance su?‘iciently plastic to permit displacement of the ?bres of the felt parallel to the face there 35 core and facing sheet together, and a moisture of, and a water impermeablepaper sheet af?xed to the opposite face of said core. 2. A composite board having a stiff and resil ient core of wood combined on each side of the core with a barrier sheet of paper impregnated with asphalt, and a Water insoluble ?lm of a thermosetting resin adhesive having affinity for both the wood and the asphalt-impregnated impervious substance impregnated within the facing sheet, said adhesive having a setting tem perature of the order of two hundred and ?fty degrees Fahrenheit, and said moisture impervious substance having the character that it is in liquid state at the said setting temperature of the ad hesive. BOARDMAN M. RANDALL.