US1969256A - Acoustic instrument - Google Patents

Description

1934- G. F. CLARK ET AL 1,969,256

ACOUSTIC INSTRUMENT Filed June 11, 1931 Fig.1.

I v g 9 Fig. 2. 3o

NVENTOR George Fr e dericK LarK, Arthur Stanley Badf'ord,

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Cf 3 m TH ll? ATTORNEY.

Patented Aug. 7, 1934 entree STATES PATENT oFFioEf ACOUSTIC INSTRUMENT George Frederick Clark, West Drayton, and Arthur Stanley Radford, Southall, England Application June 11, 1931, Serial No. 543,592 In Great Britain June 13, 1930 3 Claims. (Cl. 179-115.5)

Our present invention relates to acoustic intem, as of a dynamic loudspeaker. The coil ends struments of the moving conductor type, as for 11 and 13, preferably in the usual form of flexible example electro-dynamic loudspeakers. leads connected to the terminals of the coil 1 may,

It is an object of the present invention to proif desired, be molded in the skirt 7 and brought 7 vide a robust construction of moving coil for out'at or near the upper edge thereof. In accord- 60 these instruments, particularly for those which nee W h a y Practice, it is desirable t are large in size and adapted to handle considerbring the eads 011 Of t moving Structure at able amounts of power. point thereof sufliciently distant from the pole According to the present invention, an acoustic p s in Order to p v ta between th 10 instrument of the moving c d t type 001m leads and the pole pieces. This has heretofore 65 prises in combination with an acoustic diabeen accomplished y Cement-111g Otherwise Sephragrn, or with a skirt carrying an acoustic curing the leads along the Skirt d adiaphragm, a moving conductor embedded in a phmgmmaterial which does not soften on heating. Pref Although We have illustrated the Skirt and the 5 erably, the acoustic diaphragm, or the skirt carryleads 11 and 13 as being Within the Gone (1191- 7 ing the acoustic diaphragm, is secured to the mov- Phmgm 9, it is usually desirable to reverse the p ing conductor by th same material as that in sitions, placing the skirt 7 and the leads 11 and which the moving conductor is embedded, and 13 Outside of the end of the Conethe acoustic diaphragm may comprise a fabric Referring to 2, a coil 1, Wound on a form layer embedded in t same materiaL 3 and molded under heat and pressure into the 75 Th invention is illustrated by way of example mass of material 5 which does not soften on subi th accompanying drawing in which sequent heating, is mounted in any known or suit- Fig. 1 Shows a moving conductor according to able manner for vibration between the poles'15, 17 the invention, mounted for co-operation with a of pet'magnet e The 0011. has suitable magnet system, and secured to a skirt to it by the same material 5 as that 1n which the 80 carrying an acoustic diaphragm, while moving conductor 1 is embedded, an acoustic dia- Fig. 2 shows a modification of the arrangement phlegm part of which is Shown at Prefer Shown in ably, the diaphragm 9 consists of the material 5 Referring to Fig. 1, an acoustic current coil 1, molded upon a fabric layer for example of insulated aluminum wire, wound As above Set forth, We Y dlsclesed method on form 3, is molded under heat and pressure of and means for constructing a moving coil and into a mass of material 5 which, after being thus diaphragm for an electro'dynemic loudspeaker, molded, does not soften on further heating, the having the characteristics of rigidity and for 3 acting as the male portion of the mold rability under stringent conditions of moisture, 35 Molded to the coil 1 by means of the material 5 is heat c1191 mechameal SJPTeSSeS- our improved- 9'0 a skirt '7 which carries a suitable acoustic diacenstructlon makes posslble the use of a large phragm, part of which is shown at 9' This skirt diameter moving coil, of relatively small mass, for '7 may comprise a fabric embedded in the same high D l e e p e s that require greater than material which is used in the moving coil at 5, and usual ngldlty of the 0011 form to maintain its 40 said same material may be used for securing the circular shape especially when soft wire is used dia hra m to the skirt. the

, R liaterial 5 may be for example, a resin Because of the unitary and rigid nature of the moving coil and its form, there is no tendency for ig; the individual conductors to vibrate relative to the .5 not such as Bakelite. This material has the remammg movmg structure Furthermore 1O a cause of the improved construction of the skirt Wf PTQPeYtY of heme permanent after and its unitary relationship with the coil form, it is cured, that is, baked under heat and pressure.

and the physical continuity ofconstruction from soften under heat and the coil structure to the diaphragm, large forces 1t 15 lmpervlolls t0 Ordmery Solventsare effectively transmitted from the coil to the The ends 11, 13 of the coil 1 are for connection diaphragm, articularly at the higher audio frea Suitable Source Of acoustic q y. not quencies, without substantial attenuation. Al-

shown. The coil 1 is mounted in any known though we are not prepared to state definitely the or suitable manner for vibration in the air gap reason'for attenuation in devices with which we 55 19 between the poles 15, 1'7 of a pot magnet syshave been familiar, it is believed that lack of prop- H0 er physical continuity between the moving coil and the diaphragm is a contributing factor.

Having now particularly described and ascertained the nature of our said invention, and in what manner the same is to be performed, we declare that what we claim as new is:

1. In an acoustic instrument of. the moving conductor type, a solenoidal conductor and a skirt element, both said conductor and skirt element beingembedded in a material which does not soften on heating. 1

2. In an acoustic device, coil structure constituted by a coil form, a solenoidal conductor about said form, and a skirt element concentric:therewith for attaching the coil-structure to a ,dia-

phragm, the conductor, form, and skirt element GEORGE FREDERICK CLARK. v ARTHUR STANLEY RADFORD.

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