US2357115A

US2357115A - Sound-absorbing unit

Info

Publication number: US2357115A
Application number: US434034A
Authority: US
Inventors: Rd William A Jack; Jr Andrew Menzak
Original assignee: Individual
Current assignee: Individual
Priority date: 1942-03-10
Filing date: 1942-03-10
Publication date: 1944-08-29
Anticipated expiration: 1961-08-29

Description

Aug. 29, 1944. w K, 3 ETAL 2,357,115

SOUND-ABSORBING UNIT Filed March 10, 1942 25m 24 S 1 2a Z4 a A/voxe w 4/5 2AA TroRNEY Patented Aug. 29, 1944 UNITED STATES PATENT OFFICE SOUND -ABSORBING UNIT William A. Jack, 3rd, North Plainfield, and Andrew Menzak, Jr., Manville, N. J.

Application March 10, 1942, Serial No. 434,034

Claims.

The present invention relates to acoustical constructions, and, more particularly, to improved, self-contained. sound-absorbing units.

Heretofore, a type of sound-absorbing units has been employed in acoustical treatments, the units comprising pads of fibrous material such as mineral wool, wood fibre, hair felt, or the like. The pads are employed either directly as the wall treatment or as elements of a treatment including a foraminous pan or sheet forming a facing and supporting member for the pad.

The instant invention is concerned with a unit of the general type referred to above and has for its principal object the provision of such unit, which may be lighter in weight and thinner than the units heretofore employed while retaining at least the sound-absorbing efficiency of the prior constructions.

Another object of the invention is the provision of a self-contained unit of the type referred to, involvin both a porous sound-absorbing means, such as a fibrous felt, and a vibratile diaphragm.

A further object of the invention is the provision of such unit adapted for use, per se, as a wall facing material, or as a component of a system including sound-pervious facing and supporting elements such as the perforated pans illustrated in patent to Norris No. 1,726,500, issued August 27, 1929.

Our invention will be more fully understood and further objects and advantages thereof will become apparent when reference is made to the more detailed description. thereof which is to follow and to the accompanying drawing, in which:

Fig. 1 is a sectional view through a ceiling or wall, illustrating units of the inventionapplied thereto Fig. 2 is a perspective view with parts broken away for clearness of illustration, depicting a sound-absorbing unit in accordance with the invention; and

Fig. 3 is a sectional view taken on the line 3-3 of Fig. 2.

Referring now to the drawing, and more particularly to Figs. 2 and 3, a unit in accordance ,with the invention comprises a pad III of a soundabsorbing material. Preferably, the pad is a felted body of mineral wool fibres, hair felt, wood fibre, or the like. However, in some instances a loose, fibrous, or granular material, or a porous block such as a ceramic block, may'be employed. Pad l0 acts to absorb sound through sound decadence in the numerous interstices and openings provided therein by the fibrous or granular structure, and is particularly effective with respect to sounds of the higher frequencies, say,

to be exposed to the sound to be absorbed is a vibratile diaphragm l2, preferably comprising a heavy paper, kraft paper, or the like. It has been determined that a kraft paper weighing 0,021 pound per square foot is suitable for this purpose, but it will be understood that the particular weight is not critical although a relativcly heavy paper i preferred. To increase the weight of the diaphragm, it suitably carries a coating and impregnating material, for example, asphalt, as indicated at it. Here, again, the weight of the asphalt to be employed may vary wide y, but, for example, may be,'say, three times or more the weight of the paper. Diaphragm i2 is preferably adhesively secured to the rear face of the pad III, the asphalt coating l4 suitably acting as th adhesive for this purpose. Alternatively, the diaphragm may rest loosely on the rear face of the pad. The diaphragm is particularly effective to absorb sounds of the lower frequencies, say, those below 500 cycles per second.

Surrounding the pad l0 and the diaphragm i2 is a wrapper 16 of thin, flexible sheet'material which may be substantially impervious to air.

Preferably, the wrapper is folded as indicated in Fig. 2, and the overlapping portions, including the lapping edge l8 and tabs 20, are secured to the paper therebelow by a suitable adhesive as indicated at. per l6 may be a lightweight kraft paper, asbestos paper, or a foil or film may be used if desired. A kraft paper weighing, say, 0.011 pound per square foot has been found to be satisfactory. Where kraft paper or similar inflammable materials are employed, they may be rendered noninflammable by any conventional treatment for this purpose.

The units of the instant invention are employed in any desired manner in an acoustical treatment, for example, as illustrated in Fig. 1. In this figure, the units are shown as supported from furring strips 24 carried by the permanent ceiling or wall 26. The attachment between the units and furring strips may be made in any desired manner and, as illustrated, comprises an adhesive 28.

In lieu of the furring strip supporting means shown, the units, may be employed in pans of the type disclosed, for example, in the Norris Patent No. 1,726,500, previously referred to, the pans,

The paper constituting wrapin turn, being supported from the permanent wall by suitable T-bars or the like.

The inclusion of the diaphragm H with the sound-absorbing pad ID in a single wrapper [6 provides a self-contained, individual unit having superior sound-absorbing characteristics to thicker and heavier units as heretofore employed in which a sound-absorbing body or pad alone is used. The unit of the invention is particularly applicable where relatively lightweight and inexpensive treatments are desired, but where high sound-absorbing efiiciency must be maintained. The wrapper, in addition to maintaining the diaphragm and pad in proper relationship, serves to prevent the sifting out of loose or granular material from the pad, and also prevents breathlng through the pad.

Having thus described our invention in rather full detail, it will be understood that these details need not be strictly adhered to, but that various changes and modifications will suggest themselves to one skilled in the art, all falling within the scope of the invention as defined by the subjoined claims.

What we claim is: r

1. A sound absorbing unit comprising a porous, fibrous, self-sustaining body of sound absorbing material, a relatively flexible, fibrous sheet of a character to be vibrated to have a substantial sound-absorbing function when subjected to sound having a frequency of the order of 500 cycles per second and lower, overlying a rear face of said body, an imperforate wrapper inclosing said body and sheet, said wrapper including a light weight relatively flexible panel, overlying the front face of said body and adapted to transmit sounds of both high and low frequency.

2. A sound absorbing unit comprising a porous, fibrous body of sound absorbing material, a relatively flexible, fibrous sheet including a weighting material, said weighted sheet being of a character to be vibrated to have a substantial soundabsorbing function when subjected to sound having frequencies of the order of 500 cycles per second and lower, overlying a rear face of said body, an impcrforate wrapper inclosing said body and sheet, said wrapper comprising a light weight relatively flexible section overlying the front face of said body and adapted to transmit sounds of both high and low frequency.

3. A sound absorbing unit comprising a porous, fibrous, self-sustaining body of sound absorbing material, a relatively flexible, fibrous, asphalt coated sheet of a character to be vibrated to have a substantial sound-absorbing function when subjected to sound having frequencies of the order of 500 cycles per second and lower, overlying the rear face of said body, a light weight relatively flexible, imperforate wrapper inclosing said body and sheet, the portion of said wrapper overlying the front face of said body, being adapted to transmit sounds of both high and low frequency.

4. A sound absorbing construction comprising a plurality of units, each of which include a porous self-sustaining, fibrous body of sound absorbing material, a relatively flexible, fibrous sheet of a character to be vibrated to have a substantial sound-absorbing function when subjected to sound having frequencies Of the order of 500 cycles per second and lower overlying a rear face of said body, and an imperforate wrapper inclosing said body and sheet, said wrapper including a light weight relatively flexible panel, overlying the front face of the body and adapted to transmit sounds of both high and low frequencies, said units lying in substantially edgewise contiguous relationship and forming the interior surface of the construction, and means supporting said units in fixed spaced relationship to a wall surface.

5. A sound absorbing construction comprising a plurality of units, each of said units including a porous self-sustaining, fibrous body of sound absorbing material, a relatively flexible, weighted, fibrous sheet of a character to be vibrated to have a substantial sound-absorbing function when subjected to sound having frequencies of the order of 500 cycles per second and lower overlying a rear face of said body, an imperiorate wrapper comprising a light weight relatively flexible paper inclosing said body and sheet, said wrapper having a panel overlying the front face of said body adapted to transmit sounds of both high and low frequencies, said units lying in edgewise adjacent relationship and forming the interior surface of said construction, and means supporting said units in fixed spaced relationship to a wall.

WILLIAM A. JACK, 3m). ANDREW MENZAK, JR.