US1586596A - Phonograph - Google Patents

Description

June 1 1926.

- R. Y; BARROWS PHONOGRAPH Filed July 14 1921 -2 Sheets-Sheet 2 Patented June 1, 1926.

UNITED, STATES v I 1,586,596 PATENTVOFFICE.

'noBeRr Y. minnows, or nu rnnaronnnnw JERSEY, ASSIGNOR ronoBERr'Y.

BABROWS, INC., A CORPORATION or NEW YORK. I

PHONO GRAIH.

Application filed July 14,

The invention relates to phonographs or talking machines. An object of the inven tion is the provision of an apparatus which will give an improved tone or quality of reproduction, which will occupy less space and be less expensive'to manufacture than other types of high grade apparatus in common use. Other features ofthe invention comprise novel combinations of parts and improved details of construction, all as will be more fully described in the following specification and particularly pointed out in the appended claims.

As a result of study and experin'ientation I have discovered that the amplifying horn as usually constructed and used tapers too sharply to permit a proper expansion of the sound vibrations or impulses, and produces an increase of power by reflection in the same manner as does a megaphone. In the preferred form of the invention the sound vibrations generated in the sound box by the movement of the diaphragm therein are delivered to a large area of the free air of theroom by means of a thin membrane or diaphragm which is fixed across a shallow recess or thin air chamber, the interior of which is in communication with that of the sound box.

Although the large membrane '01- diaphragm referred to offers but slight reslstance to the sound vibrations, it is apparently sufficient to cause them to be distributed over the whole interior of theair chamber, whereupon they are imparted to the free air of the room over alargearea.

It will thus be noted that I obviate the effects resulting from the use of a horn or amplifier having a considerable taper by means of a construction in which no horn or similartapered body is used, the present construction operating in accordance with a quite different principle. Further and more specific objects and advantages w1ll more clearly appear from the detailed description given below.

In order that the invention may be more clearly understood attention is hereby dirooted to the accompanying drawings forming part of this application and'illustrating, by way of example, certain embodi mentsof the invention.

In the draw ngs: 7

Fig. 1 represents a View partly front elevationend partly vertical section of a.

1921. Serialin. 484,540.

tform of construction embodying the invenion; p

Fig. 2 is a vertical section taken on line- 22 of Fig.1;

Fig. 3 is a horizontal section taken on line 33 of Fig. 1';

Fig. 4 is a detailvertic al sectionttaken through the cover and the connection ofthe tone arm with the amplifyingrecess;-' I

Fig. 5 is a vertical section taken on line 55 of Fig. 4; and v I Fig. 6 is a vertical section througha -modified form of construction.

Referring first to Figs. 1 to 5 of the drawings, a casing 1 is illustrated, preferably supported on legs 2. A motor 3 of any desired construction is indicated as carried by a frame 4:, preferably at one end of the casing. The record support is provided, in the construction illust-ated, by the turn table O on which the record indicated at 6 may be placed, the turn table being mounted on the vertical spindle 7 for rotation by the motor in the usual manner.

The cover 8 is preferably hinged to the rear upper edge of easing lby suitable hinges, such as the hinge indicated at 9, in Fig. 4: The cover is adapted to close down over casing 1 when the turn table 5 has been removed from position on spindle 7 and the sound box and tone arm suitably secured to the cover, as will be described. lVhen the cover is in its open position, as shown in the drawings, it

may be held in such'position by means .of a

brace 10 adapted to extend diagonally from a side of the casing to a side of the cover. and be secured in such positionby means of thumb nut 10. 7

Cover 8 is provided with an air chamber,

or recess 11, which preferably takes tllGTOlhL of a thin rectangularenclosure. The front of this enclosure 1s covered by a diaphragm 12 while the back and sides of the recess or air chamber are closed by the heavy wooden portions of the cover construction, with the exception of an opening at one point by which connection is made with the sound between the soundbox' and the air chamber 11. 1 Y

The large diaphragm- 12 may be a'thin membrane of paper, cloth, or other suitable material. It should be light in weight, and more or less air tight, and should be preferably fared in place to lie flat but not too tightly stretched, since in that case it will offer too much resistance. I have found that the linen which is treated to make the same air tight for the purpose of forming window shades is very well adapted for this purpose.

I have illustrated diaphragm 12 as secured to a frame 16 which may be secured to, or formed integral with the cover 8, the sides of this frame preferably being parallel to the outside flanges 17 of the cover member, which are adapted to seat against the upper edges of easing 1. The diaphragm or membrane 1.2 may be secured in position on the frame 16 by uitjable means such as a thin strip 18 positioned thereon and secured to the frame 16 along the edge of the membrane 12 by suitable screws 19, or the like.

I have found it desirable that the air space within chamber 11 should be comparatively thin in order that the force of the vibrations transmitted from the diaphragm of the sound box to the diaphragm 12 should be conserved. By way of example I may state that I have found a distance of one-half inch between the back of the air chamber and the diaphragm 12 to. be sufficient and to give good results when the diaphragm 12 has a surface area of 200 square inches or less.

It is desirable that the back of the air chamber 11 as well as the sides thereof, formed by frame l6, should be of comparatively hard and non-resilient material, in order that the membrane 12 should receive the full force of the vibrations. The cover 8 and frame 16 may suitably be formed of wood.

l i hen a disc record is reproduced, as is indicated in the drawings, the tone arm, or connecting arm 15, must, of course, be so connected with the cover as to enable the stylus to travel across the record and also to be lifted therefrou. I have illustrated :a form of tone arm connection which is suitable for the purpose and which constitutes one of the features of the invention.

As shown, a hollow bracket 20 is secured to cover member 8 to extend forwardly therefrrnn when the cover is in rest position, the rear end of this hollow bracket communicating with the lower end of air chamber 11 below the membrane 12. The bracket or fixed conduit member .30 is provided at its forward end with upwardly extending tuliiular portion 21, the upper edge of which is rounded, as shown. at e o e a m or iaiov ble onduit membe s p ovided at its end distant from the sound boxwith a downwardly turned e eien 3 1, 11... .11

with a bearing surface 2d adapted to rest on the rounded upper edge 22 of tubular portion 21. The bearing surface 24 is preferably formed as a segment of a sphere, the center of which may be located in the lower portion of bracket 9.0.

The upwardly extending tubular portion 21 of bracket is preferably provided with achase or groove 25 extending peripherally about its outer surface. The downward ez tension 23 of tone arm c ntinues below the bearing surface 2 1, as atubular flange 26 surrounding the upper partof the tubular portion 21 of bracket 20, the inside diameter of flange 26 being greater than the outside diameter of tubular portion 21.. A pair of lugs er iend inwardly from the sleeve portion 26 into "the chase 25 at diametrically opposite, points so as to prevent side rocking of the tone arm when a record is being reproduced, these two lugs preferably taking the form of screws 27 which are adj ustably mounted in sleeve portion 26 of the tone arm to engage against the upper horizontal surface of chase 25, as is shown in Fig. 5.

lVith this arrangement the tone arm may, of course, swing about bracket 20 in a horizontal plane while the record is being played. The tone :arin may also be swung upwardly to change the needle or for any other purpose, in which case the tone arm swings about a horizontal axis extending through the center of curvature of bearing surface 24;, the screws .27 not binding when the tone arm is lifted since the center about which the surface 2 1 is formed is below the bearing formed by the engagement of surfaces Q l and 22. The tone arm and sound box will, of course, be held against rocking from side to side. by the engagement of screws 27 with the upper edge of chase .25. A step may, of course, be provided in chase 25, if desired, to. engage one of the screws 27 and thus limit the range of horizontal swinging movement by the tone arm. The joint so formed will be substantially air tight.

When the cover is to be closed the tone a rm SliOlllCl' be secured in a fared position to the cover. lhis may readily be accomplished by the .pi ovisioi- -ogt a spring clip 28 secured to the cover, and having a depression therein or hole therethrough. Sound box 1?) is provided with a lug 29 which adapted to engage in this hole or depression when the tone arm is swung into the position shown in dotted lines in Fig. 3, lug 29 wiping past the edge of the spring member :38 and seating itself in the hole or depression therein, referred to. hen a record is to be changed the arm 15 may be swung into the latchedposition described or the lug?!) may besimply positioned on top of slip Casi 1 is preferably provided with a turn table has been thus removed from its operative position ample room will be pro vided forthe tone arm and sound box within the cover when the latter is closed.

The invention may, of course, take a number of forms, as will be readily understood. In Fig. 6 I have illustrated a casing 1 in which the air chamber 11 is formed at the under side of the horizontal member 30 of the casing. In this case the motor 3 is carried beneath supporting member 30 with the turn table 5 above the same,the sound box 13 being carried by a tone arm or connecting arm 15 the opposite end of which is provided with a suitable pivoting connection (which may be similar to that described above) with the bracket 20 mounted on top of member 30. In this case, of course, member 30 is provided with an opening 31 therethrough, by which connection is made from the interior of the tone arm to the thin horizontal air chamber 11 The bottom of the air chamber is covered by a membrane 12 The casing 1 maybe closed by a suitable cover 32 which may be closed while the device is being operated.

It will, of course, be obvious that the'device may take various other forms. The large diaphragm 12 may be suitably decorated and mounted in a framein the same manner as a picture, the frame being secured to a wall separating a room from a closet in which the phonograph mechanism may be placed so that scratching and other undesirable noises may be rendered less audible to the listener in the room. I 7

It should be understood that the invention is not limited strictly to the details of construction as described, but is as broad as is indicated by the accompanying claims.

Vhat I claim is 1. In a phonograph, the combination of a member having a substantially rectangular sound amplifying chamber, a resilient diaphragm covering said chamber and forming one side thereof, a sound box, and a tone arm providing a direct pneumatic connection between the diaphragm of said sound box and said resilient diaphragm, said chamber and tone arm forming a substantially air-tight enclosure, the walls of said chamber other than said resilient diaphragm'being substantia'lly non-resilient, and said resilient diaphragm being many times larger than the diaphragm of said sound box.

2. In a phonograph, the combination of a member having a substantially rectangular sound-amplifying chamber, one of the side Walls ofwhich' is formed of resilient material and the remaining walls of which are formed of comparatively non-resilient mate rial, the distance between said'side walls being slight in comparison with the surface dimensions of said resilient side, a sound box, and a tone arm connecting said sound box and chamber, said sound box, tonearm and chamber forming a substantially air tight enclosure.

In aphonograph, the combination of a casing providing a rotatable record support, a cover hinged to said casing, having shallow rectangular recess formed therein, a diaphragm covering one side of said recess, a sound box, and a tone arm connecting said sound box and recess, said sound box, tone arm and recess forming a substantially airtight enclosure. g I

4. In a phonograph, the combination of a casing providing a rotatable record support, a cover hinged to said casing, having a shal low rectangular recess formed therein, a flexible diaphragm covering said recess, a sound box, a hollow bracket secured to said cover with its interior communicating with said recess, and a sound conduit carrying said sound box and communicating therewith and movably connected to said bracket,

said sound box, conduit, hollow bracket. and

recess forming a substantially air tight enclosure. a

5. In a phonograph, the combination of a casing providing a rotatable record support, a cover hinged to said casing, having a shallow recess substantially rectangular in outline formed therein, a flexible diaphragm covering the opening of said recess, a sound box having a stylus adapted to track a record carried by said record support, and means movably connected with said cover to afford a sound passage extending from said sound box and to the portion of said reeess which is lowermostwhen said cover is open.

Signed at New York, in the county of New York and State of New York, this Sthday of July, A. D. 1921. I

ROBERT 1*.BARROWS.

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