US2017548A - Building construction - Google Patents

Description

0t 15, 1935- M. c. RosENBLATT' 2,017,548 BUILDING' CONSTRUCTION I Filed Jan. 14, 1950 2 *Sheets-Sheet l Fig] frr

INVENTOR ATTORNEY Oct. 15, 1935. 1 M. c. ROSENBLA'TT y2,017,548

BUILDING CONSTRUCTION y Filed Jan. 14, 1930 2 Sheets-Sheet 2 @www O0000000000000000000001 3,5# 57/2) OOOOOOOOOOO-OO J0 O C l O C f6 L4 u 60 www VN TOR ATTORNEY tion of the present type of ce Patented Oct. 15, 1935 UNITED STATES APA'I'IEINT 'OFFICE BUILDING CONSTRUCTION Maurice C. Rosenblatt, Philadelphia, Pa'. Application .Imam 14, 1930, serial 10.420.668 v L 1 claim; '(01.20-4) Thisinvention relates to. building constructim. at least, as follows. The superficial acoustic AThe invention pertains more particularly to ceiling constructions of buildings and to a modificaconstruction so as. to present numerous advan ages as 'will be .y pointed out but which particularly obviates all present forms of, acoustical treatment or applications.

It will be clear, there are many features of the presentinvention available or applicable td present types of acoustical .treatments or applications, for which purpose it may be necessary to enlarge somewhatv upon the acoustic problem generally. This should not be understood to minimize oralter. the.

importance of the invention in the art of building constructions generally. 1

In the art of ceiling constructions according to universal previous practice the ceiling proper has been a heavy, 'rigid and expensivenelement suspended below in spaced relation tothe supporting slab of the building. Owing to the lpresence of e many factors which will be obvious to those skilled in the art, it is customaryto provide afvery. appreciable space between the ceiling andthe slab,

which may vary between six and eighteen inches more or less. In the conventional ceiling construction, according to previous practice, a number of vertical hangers are suspended from the slab with their lower ends connected to a series of transverse girders in substantially grid-iron relation, to which a layer of expanded metal or other lath is amxed, which latter is the support for the three or more distinct coats of` plaster which are subsequently applied toV nish the ceiling. Owing to the weight 'of the plaster and lath, the

hangers .and girder elementsmust be of heavy 4construction which -forms a large factor in the cost of the ceiling. Moreover, there is no way of ltrui`ng up the ceiling other than by applying more plaster to bring a desired point upto the level.

It will be necessary to .allude topres-ent types A of acoustic treatmentsin order to fully appreciate the advantages incident to the present invention.

Acousticv treatments, in the forms' presented here- 'tofore alwayshave been, at best, merely supers the description proceeds, that the ceiling over the conventional construction treatment is very expensive. As they cover and conceal a structural surface which has already previously been finished or at least substantially completed at appreciable cost, there is a further 5 factor of high expense in this duplication of nish. Such supercial treatments being of an .appreciable thickness materially reduce the ceiling height and the volume of the room to be treated.

They add appreciable weight to structures which 10 are already heavy. They are not adapted for .making alterations, and the like, behind or in the treatments. The present treatments are so read-` ily eiected by age and by varying conditionssuch assettlement, shrinkage, humidity, as to be'sublsf stantially temporary or at least impermanent. Of possibly greatest importance is their relative inefliciency from a sound absorbing view-point.

, This latter is despite the fact that -the'supercial 'acoustic treatments require costly sound absorb- 2o.;- I. ing means, and require expensive -skilled labor to apply, but which,` owing to the very nature of the treatment cannot provide enough sound absorbing material to be ,of very high absorbing value. For instance, in that type-of treatment 25 in which a layer of sound absorbing material, such as felt, or the like is pasted or otherwise supported upon the surface, there is a denite limit to the thickness of the vfelt that may be so applied, as.:

owing tov its structural weakness and to the fact- 30,'

that the stress is transverse of the material;j it tends to pull itself apart. Moreover, cements can only support a certain limited weight beyond which it is impractical and expensive to go. In

other words, attempts to increase the `eiiiciency of 35;

the modern supercial acoustic treatment requires the expenditure of greater and greater sums for the result. In vthe average supercial treatment then, relatively thin layers of 4absorbing 'material are used, which use militates against high sound absorbing efliciency.

The instant invention presents a'construction `so radically diilerent from, previous practicesV in acoustics as to be. revolutionary, as it presents a ceiling construction having all of the necessary 45,'

attributes of any vceiling construction, with an integral, built in, sound absorbing structure;

which obviates all of the disadvantages of pre-- vious acoustic practices without added cost for corporating as an inherentpart thereof a sound 55, I

absorbing structure; to provide an acoustic treatment of unprecedentedly high sound absorbing value; to provide a process for acoustic treatments generally which improves the value of sound absorbing treatment; to provide a ceiling construction for buildings which incorporates an acoustic treatment of unprecedentedly high sound absorbing value Without any increase in the cost of the ceiling construction; to provide a building construction includingrmeans for im- -proving the 'installation of a sound absorbing medium; to provide in acoustic treatments an improved outer exposed surface; to provide in building constructions a new ceiling finish; to

l5 provide a decorated porous membrane for acoustic treatments without artificial or mechanical perforations in the surface; to provide an improved hanger for ceilings; to provide improvements in membranes of acoustic treatments such that the natural porosity of the membrane can be utilized despite the applications of a decoratingcoat thereto; to provide a ceiling construction incorporating an acoustic treatment securing 100% absorption ofthe incident sound energy; to provide an acoustic treatment in which the sound absorbing element is of far greater area than the' exposed concealing element associated therewith; to provide standard building construction elements as the support for an acoustically` absorbent ceiling construction; to provide an acoustic treatment of such high sound absorbing efficiency that but a minimum of area of treatment is necessary to treat a given compartment'of the building; to

" provide a ceiling construction, incorporating sound absorbing structures, which is lighter in weight than the standard building construction; to provide an acoustic treatment in which the sound absorbing element may be of waste material and of the cheapest sort without adverse' effect either in appearance or efliciency; to provide a ceiling construction incorporating an acoustic treatment of such simplicity that it may be installed by relatively unskilled labor andv at low cost; to provide a ceiling construction which can be levelled up bythe operators without the customary wastage of plaster to secure the result; to provide a ceiling construction incorporating an acoustic treatment with which soundj damping means may be associated at low cost but with high eiciency; to provide an acoustic treatment which may be made fire-proof at little cost; to provide a membrane f or an acoustic treatment in which the lines ofthe supporting,

strips may be obliterated without decreasing the sound admitting and absorbing eiciency; to provide a ceiling construction incorporating an acousticI treatment which can be made sound proof as well as sound absorbing, and which comprises a heat and cold insulator; to provide a ceiling construction providing for damping the vibration of pipes and Ventilating ducts without interfering with the celing construction; to provide an improved hanger for ceilings to -preclude the transmission of vibrations between the ceiling and the slab; and many other objects and advantages as will become more apparent as the ing the association of sound proofing elements in the ceiling,

Fig. 3 represents a further modified form of ceiling installation in vertical section in which acoustic materials of reproof construction may 5 4be used, s

Fig. 4 represents a fragmentary plan, partially in section of the supporting framework of the ceilingin an illustrative form,

Fig. 5 represents a plan and Fig. 6 represents 10 a section through a modification of the ceilingof this invention disclosing the combination of l portions of a standard ceiling including a plaster or similar decorated ornamental surface, with a restricted but highly ecient area of lsound ad- 15 mitting and absorbing exposed surface,

Fig. 7 represents a fragmentary elevation of the device for'maintaining tension on a stretched portion of the ceiling, i

Fig. 8 represents an elevation of a vibration 20 damping hanger such as may be used with this invention,

Fig. 9 represents a fragmentary vertical section on a highly magnified scale of the exposed surface of the ceiling according to one portion of 25 the invention, and

Figs. 10 and 1,1 represent fragmentary' plans of the membrane disclosing the lm forming layer of paint applied thereto and the pore openings formed by air pressure after blowing or sucking 30 the paint film from the membrane. 1

It will be understood that the ceiling of this invention is applicable to many different types of building construction and is not restricted to those providing a concrete slab as the ceiling 35 support, as this supporting oor may obviously be formed in any desired manner. Referring to Fig. 1,y the slab I2 may terminate at or be intersected by a wall I3. A plurality of generally ver- -tically'extending hangers I4 are connected to the 40 slab to hang therebeneath in any number, order or size desired. The hangers III may be of anydesired sort as tc. shape, weight, length or material according to the requirements o f the particular installation. Thel hangers may be pcr- 45 manently attached to the under side of the slabf or may be attachedK as removable elements engaging permanent inserts, mounted on the slab. At any rate there are anumberof these hangers upon which the ceiling is supported. The hang- 50 ers are illustrated for conveniencel as of angle iron, but the forms they may assume include channel iron, rods, straps and the like, fabricated in shops or on the job as may be indicated. They may comprise the isolating or vibration 55. damping hanger disclosed in Fig. 8. The feature of this hanger is that the strain on the hanger is transmitted through a wrapping of felt or other damping element. In an illustrative form as observed in Fig. 8, there is provided an outer 60 cylinder I 5, which is hollow and is supported from the slab in any desired manner. The cylinder is provided with'a vertical slot or slots I6, and at the lower open end has one or more bayonet join. slots I'I.` Mounted within the outer cylinder is a 65 smaller rod or tube I8, carrying a rigid crosspin 20 slidably disposed in the slots I6, and carrying in slidable relation toward its lower end a plug 2I, having radial pins 22, arranged to engage in the bayonet joint slots I1. The inner rod or tube has clearance from the outer cylinder and is embraced by a wrapping or tube of felt or other damping element 23, the upper end of which impinges upon a washerv 24, and the lower end envgagedby the plug 2|.' It will be clear that ac; 75-- braced between the washer 24 and plug 2| will be determined the effective lengthof the hanger.

With the proper amount of damping material the eil'ective length of the assembled hanger will be as desired and the tensile strain on the smaller rod or tubewill be transmitted through the felt or damping material to the outer suspended cylinder. A hanger as disclosed serves quite well `for general hanger purposes but is particularly available and desirable to preclude the transmission of vibrations between the ceiling and the slab. 'Obviously it is contemplated that where conditions warrant aV hanger of the .characteristics of that shown in Fig. 8 may be used with the instant invention.

Regardless of the 'hanger used, there will be transverse supports, such as wires, rods, straps or channels, or the. like. 25,-'extending horizontally and connecting with desired hangers to brace the unit, and form supports for the later suspended absorbing'material. 'I here will be as many transverse rods and spaced such distances as are necessary under the circumstances of a particular installation. It may be -found best. for instance under certain conditions, to stagger the series of hangers so that the attachmentof thetransverse rods may be lmade to alternate pairs of hangers. /In any case the transverse rods will be connected to the hangers somewhere between the top andbottom of each hanger, and

preferably at or just below the approximate centers of the hangers. Obviously the location of the transverse hangers will depend in certain measure upon the amount of sound absorbing or damping material to be installed and the thickness of the entire ceiling. O The lower terminals of the hangers will be connected to longitudinally extending strips or bars, such as channel bars 26, extending preferably perpendicularly to the 'transverse supports, and in vertical spaced relation thereto. The hanger and rod assembly will thus form a rigid and inflexible unit braced both ways, although the longitudinal and lateral bracings will ot be in the same plane substantially, but in vertically spaced planes, in the preferred form. Obviously the lowermost series of rods may be supplemented by additional rodsto form .of the ceiling structure.

a grid of extra rigidity, if this should be desirable.

It will be understood that this will be the framework which is erected to `receive the remainder It will be notedfurther, that if the hangers are of the type shown in Fig. 48, or of an equivalent construction, of

which many will occur to vthose skilled in the art, :the lower faces of the channel bars or the like 26 may be levelled up into. exactly the level desired, by making adjustments of certain hangers. Such adjustments will also be made to cause the ceiling to adhere to predetermined heights so that these heights may be secured without the deviations formerly inevitable with ceiling constructions. l

The transverse supports 25 are arranged to be disposed in the waste space of the ceiling, that lmanner (not shown).

easily and without strain. It is usually unnecessary even to attach the material ,to the bars, as it merely rests upon them and -is not subject to displacing stresses. form at least, the material be pliable and susceptible to bending so that a great area of it may be inserted in the ceiling by forming it inv loops or the like, as shown. It may take many forms, such as reinforced felts, fire-proof felts. quilts, ground cork, mineral wool, and the like. In the various felts that are available it is of interest to note that owing to the manner of forming the felts, the fibers of the felt lie in substantial planes parallel with the faces of the finished felt, and although slightly admixed. are-of such construction that lateral stresses against the grain may cause the felt to separate into strata,

.but the tensile strength of the felt is much greater. It is of importance to note that according to this invention the only stress on the felt (when felt is used), comes from the weight of the loop suspended between the two transverse bars, and this strain is almost entirely tensile.

. looped strip. of sound absorbing material may be attached to the end transverse rod in any desired Itis to be noted that the looped material is to be as thick as desired, and may be lcomprised of several different layers. Its thickness-is only limited by the distance that i the ceiling construction is suspended below the slab or floor above. It is to be observed that by providing the looped material as disclosed, a quantity of material may be introduced which in area is far greater than its reiie'cted area. To` secure the introduction of more material in' the given ceiling area it is but necessary, obviously, to increase the number or length of the loops. It is quite easy to secure an area of sound absorb- Obviously, in the preferredent material that is twice the area ofthe eiective ceiling area, or an even higher ratio may be attained, according to conditions. For this purpose it is contemplated that wires or the like. (not shown) may be inserted into the rigid ceiling framework between the transverse bars vas auxiliary loop supports. In any case it is preferable that therev .be a number of loops so'gthat the leffective sound absorbing area of the 'material is appreciably increased so that the unit eiliciency of the material (the reected unit) is multiplied several times. This is of far reaching importance as it enables the absorbing material to attain an unprecedented sound absorbing'efflciency. For instance, a felt of one inch thickness may in its flat condition absorb as high as 50% of incident sound, butwhen installed as disclosed herein will easily absorb 80% of the incident sound, per unit of reflected area and without diillculty; byproviding suiiicient area of absorbing material the treatment may be so -increased in efciency as to secure 100% absorption of incident sound, which is a complete absorption as compared with the absorption standard, which is known to be the open window. The

sorbing area with a minimum of cost or trouble, but obviously the same eiect may be secured in other ways, as, instead of looping the sound absorbing material over the transverse bars, as

shown, the material may be hung from the transverse bars or from other supporting elements, in the 4form of a profusion of vertical strips for instance, (not shown) It is pointed out that whereas with the present superficial imposition constituting the acoustic treatment, the sound absorbing elements used in such superficial applications must have good surface texture, 4uniformity of thickness, homogeneity of structure, and the like, which requirements contribute materially to the high cost of the treatment, the sound absorbing elements available for the instant construction can be relatively crude, unreflned and therefore relatively inexpensive. Indeed the materials used may even include inexpensive waste material.

The problem of sound proofing designed to .preclude the transmission of Vibrations from one compartment of a building to another, or into the structure itself, according to previous practice, was a separate consideration and had to be accomplished separately from the acoustical application. In the instant invention sound proofing may lie-'combined with lsound absorbing very simply/and economically, as shown in Fig.

2, in which with the identical assembly already described, and with the loops of acoustic or sound absorbing material 21 hung upon the transverse supports 25, layers 3| of damping material, such as a layer or combination of layers of artificial fiber board, are laid upon the high parts vof the loop and upon which they permanently rest. A refracting layer of `materialof different density from layer 3|, as layer 32 may be laid upon the fiber board 3| and if desired still another layer of damping material of any desired sort as 33 may be superimposed on the refracting layer 32. These sound damping stratications need not be fastened in position but simply laid upon thepeaks of the loops or other suitable supports. While it is desirable that the damping layer 3| be of a relatively stiff material, damping layers 32 and 33 may be relatively soft and pliable if desired. v

It will be understood that the lower portion of the ceiling may comprise any desired exposed decorated or undecorated surface so long asa portion at least, of sound waves incident upon the exposed surface may pass into the ceiling proper to impinge against the surface of the sound absorbing material. In its broadest aspect therefore, it may. suffice to note that the ceiling is. finished with a more or less porous surface element' It will be obvious to those skilled in the art that the exposed surface 34 may assume many forms, and be of many materials, but in the preferred form is preferably comprised of a stretched and taut porous membrane 35. to which an exposed finish element. 36 is pasted. In order to mount the finish members in position there are provided a number of furring strips 31 (Fig. 1) vwhich may be supported in the plane of the bottom reenforcing bars 26, or, may be attached to the under surface of said bars as shown in Figs. l, 2, 3, and 4. 'The furring strips may be attached in any desired manner whatever to the channel bars 26 and in the. form disclosed in Fig. 1 are permanently secured in4 a fixed position. A membrane 3,5 may be lattached to one furring strip extending transversely across the ceiling in a substantially horizontal plane and passing around the end of the adjacent furring strip and may be afxed there;- to in any desired manner. A complemental furring strip 38 may be attached to the furring strip 31 about the corner of which the next expanse 5 may be pulled. In Fig. 1, furring strip 31 is disclosed as supporting a lug 40, the outer end of which carries a spring 4| arranged to be engaged in any desired way with the end of the membrane 35 as at 42. vThe purpose of this spring is to 10 maintain the tension of the stretched membrane, e as will be clear. In Fig. 2 a slightly modified form of attaching device is disclosed in that a plate 43 having serrations or teeth 44 is mounted on the side of the furring strip with the end of membrane hooked upon the teethof the plate. In Fig. 'Z a further modification is disclosed in which the tension on the stretched membrane is maintained by l spring pressure by providing the furring strips 45 with bolts or pins 46 engaging in longitudinal slots 2 0 41 in the channel bar 26 so that the furring strips may have a limited movement. Tension on the membrane is secured by providing some such device as a bowed spring element 48, arranged to seat upon and urge the respective furring strips 25 45 apart. It will be understood that the rst furring strip is located by a wall so that tension of' the spring in one direction is absorbed by such wall, but wherein Vsucceeding furring strips are urged away from said wall to maintain the ten- 30 sion on the membrane. It will be apparent that with a device as disclosed in Fig. 7 it will be 'possible to finish the last panel by compressing the spring 48, while the furring strip is spaced from the wall as by blocks (not shown) after the mem- 35- brane is attached thereto, then by removing the blacks holding said furring strips, to permit the furring strip to move and impart tension to the membrane in such last panel. Y

The invention contemplates important features Q V applicable generally to the art of acoustics, and -one of these features is the method by which a decorative nish is applied to the finishing members substantially without impairment of the` natural porosity of the member. One of the fac- 45 tors militating against the use and success or eiciency of fabric membranes in the past, has been the'- fact that although in their natural highly porous condition they have been very efficient, yet the," application of a decorative nishmsuch as paint, has created a film which is not only reflective of incident sound, but which, through closing the pores of the material, has rendered it of low acoustic value. The ceiling element 35 is preferably open mesh fabric such as burlap, aber` 55; deen cloth, and the like, or it may be asbestos cloth or perforated reenforced asbestos paper, or a wire" mesh, or similar material including aA rigid apertured sheet such as sheet iron and the like. It is probable that burlap will, in many cases, be 60, the preferred material and this preferably is bleached before application. The burlap or other ceiling element receives and carries the rst coat of paint. This may be applied in any desired manner as by brush or by sprayfand the paint Q5.

pingen upon strands of the fabric win be deposited on said strands, but that the particles4 passing through the pores will be blown completely through the membrane and possibly deposited upon the loops of absorbent material suspended above the membrane. The spray gun may be so used that the pressure applying the paint is sufiiciently great as to prevent the formation of the film, if desired. In either of these cases, however, the important effect is achieved of depositing color or pigment upon the porous material without clogging up or covering over the pores.

Immediately after the paint is applied and while it is still wet enough to be so treated, the surplus material, if any, is blown out of the mesh so as to maintain its original porous condition. This may be accomplished in a number of ways as by a simple motor driven blower or by Vacuum equipment. The ceiling Y element 35 may be treated with dry pigment to create the desired color before its installation in the ceiling, or it may previously or subsequently be stained or dyed. V In Fig. 9, the ceiling element 35 is disclosed on a highly magnified scale and with the paint 50 attaching to the meshes of the fabric in isolated discontinuous points or area so that the porosity of the element 35 is substantially maintained. This method of procedure in the finishing of an acoustic membrane so as to secure hiding power without the formation of a lm, is important.

The nish element 36, which, preferably comprises a fabric of possibly finer mesh than the ceiling element 35, and may be of any of the materials available for the ceiling element, is pasted or cemented to the ceiling element 35, preferably after the ceiling element is stretched in position and directly following the pasting operation and while the paste is still moist enough to work, surplus paste or cement is blown or sucked out of the meshes in the same manner as previously described. The finish element 36 may be applied in a continuous layer, with joints abutted together or blinded, or it may be applied to form any desired design or relief. The second coat of paint, or the like, is applied to the nish element and the surplus moist material is withdrawn asbefore to maintain the porosity of the finished material. In this manner therefore, the painting of the treatment does not detract from its sound absorbing eect, and it lmay therefore be repainted and cleaned repeatedly at will in the Same manner, without detrimental effect. It is of interest to note that although there may be two coats of paint applied, yet owing to the fact that they are applied to superimposed layers, the layers of paint are slightly separated and owing to the staggered effect available with fabrics of different mesh, the hiding power of the two coats o of paint is substantially utilized. i

In many cases it may be desirable to provide decorated plaster panels, or the like, in the ceiling which with present superficial acoustic treat- 5 ments would be impossible. Owing to the extraordinarily high sound absorbing emciency of the sound absorbing material arranged as disclosed in the invention, as an incident of the fact that sound waves travel and may impinge upon the 10 absorbing material in lan infinite number of angles, it is possible to provide an effective acoustic area of ceiling, which, according to all previous standards would be inadequate for acoustic purposes, but which lead to or open upon areas 15 of absorbing material of such great Vabsorbing power, as to render the unit absorption for the ceiling still of unprecedentedly high eiciency. For instance, in the disclosure of Figs. 5 and.y 6, the ceiling is provided with moldings, beams and 2g vthe like 5|, 52, 53, and 54 connected-by an expanse oi plastered ceiling, as 55, which may be built up and supported upon reinforced hangers 56 supporting metal lath 51 and the plaster layers and the moldings. In an area defined by 25 molding52, 53 and 54 there may be acoustic panels, respectively, v58, 60 and 6l, comprising stretched membranes or other porous exposed material so as to impart a finish Vto the acoustic panels but to provide passage ways for the sound 30 ,y

waves leading to the many loops of absorbent material suspended within the ceiling above the ceiling finish as disclosed in Fig. 6. With the panel effect disclosed in Figs. 5 and 6, the avail. able acoustic area of the ceiling may form as low 35 as 30% of the entire area, but by providing enough of the sound absorbent material over the entire area approximately, and by maintaining the porosity of the finish in the acoustic panels, such a high degree of absorption may be had as 40 to give a unit absorption for each panel of approximately y Obviously the invention disclosed herein will be subject to many modifications, a's will be clear to those skilled in the art, and it is desired that 45 all such shall be construed as within the scope of the `invention as recited in the appended claim. j

I claim as my invention:

In a ceiling construction. a supportingslab, an 50 'area yof ceiling material including a restricted

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