US1897294A

US1897294A - Loud speaker and like apparatus

Info

Publication number: US1897294A
Application number: US553958A
Authority: US
Inventors: Bernard Marcel
Original assignee: Societe Francaise Radio Electrique
Current assignee: Societe Francaise Radio Electrique
Priority date: 1930-08-14
Filing date: 1931-07-30
Publication date: 1933-02-14
Anticipated expiration: 1950-02-14

Description

Feb. 14, 1933. M, BERNARD 1,897,294

LOUD SPEAKER AND LIKE APPARATUS Filed July 30, 1931 i z E a 6 F 2 a 9 r MARCEL BERNARD- INVENTOR 2 MWLLMQ ATTOR N EYS Patented Feb. 14, 1933 i 1,897,2Q4

outrun s'rarss P'rs'r MARGEL BERNARD, F PARIS, FRANCE, ASSIGN'OB I0 SOCIETE FRANCAISE RADIO- ELECTBIQUE, OF PARIS, FRANCE, A CORPORATIGII 0F FRANCE LOUD SPEAKER AND LIKE APPARATUS Application filed July 30, 1931, Serial No. 553,958, and in France August 14, 1930.

The present invention relates to improve said cone 0 and coil 6 is suspended in a simiments in loud speakers and like apparatus and lar manner from the main structure or framehas for its objectto prov'deasound-reproducwork of the apparatus (not shown). The

ing and sound-receiving device having a unirigid elements together with their suspensions 5 form response to applied vibratory energy are designed more favorably to respond to 5 over as wide a range of acoustic frequencies difierent frequency bands of vibrations which as possible. as far as possible, succeed one another with lVit-h this object in view it is proposed in out any interruption of continuity in the freaccordance with the present invention to emquency scale.

ploy as the vibratory element a plurality of In the embodiment illustrated in Figure 2 o conical surfaces elastically connected together a single circular air-gap is provided between and driven by means of one or more coils imconcentric pole-pieces N, Q, A movable coil mersed in one or more circular air gaps of a B is immersed in this air-gap and is supported magnetic circuit and traversed by alternating in the usual manner upon a hollow tubular current-s corresponding to the sound vibramember 4 and this in turn is rigidly secured 65 tions to be reproduced or picked up. to a truncated conical membrane 01- A An essential characteristic of the invention 0nd truncated conical membrane 0 concentric resides in the fact that the coaxial conical surwi h the first,is connected by a flexible suspenfaces which form the vibratory system of the sion means S at 7 on an intermediate circle apparatus are interconnected by elastic con- 0 the Cone 0 and at its outer periphery pro- 70 necting means which in the case of least one vided with a flexible suspension means S of the conical surfaces is attached to said surwhich is preferably clamped between or seface on a circle which is intermediate the incured to a pair of ring members 9 and 10 ner and outer peripheries thereof, which thus form a suspension or support for The invention will be better understood by said cone. These ring members may be se- 75 reference to the accompanying drawing which ured together and spaced from another ring represents, by way of example only, two parmember 11 by several tie rods or

bolts

8, 8, ticular methods of carrying out the invenwhile a hollow magnet 6 may in turn be fas- V, tion. tened to ring member 11 of the frame thus Fig. 1 is a diagrammatical section of a loud formed. The same conditions relating to the 80 speaker embodying the first form of the infrequency response favored by each diavention. phragm referred to in the description of Fig- Fig. 2 is a side section of such a loud speaker ure 1 are also applicable in the present case. embodying the second form. Flgure 3 shows, by way of example only, a V

Fi 31 a l i f th suspensien suspension devicePwhich may advantageousher to which the diaphragms and moving lybeemployed in connection with the particucoils of the loud speakers may be attached. lar embodiment illustrated in Figure 2. In

In the views, the same reference indicia rethis 05186 the moving Coil B Which in ig- 2 is fer to the same or corresponding parts. shown supported on the hollow tubular mem- In the embodiment shown in Figure 1 a. ber 4i is attached by the same to the central magnetic circuit having concentric poles N Q circular part a. The suspension of the coil B is provided with two annular air-gaps 1 1 and consequently that of the cone 0 which is which are likewise concentric. In the said rigidly attached thereto is of course effected air-gaps are disposed cylindrical coils b and at S on the circle 7, as already indicated, on

7J2 which are rigidly secured to truncated conithe surface of the truncated cone 0 intermecal membranes c and 0 respectively. The diate the ends thereof and also at the small rigid assembly comprising the cone c and its ends of the two truncated cones by the tabs X associated coil 5 is suspended in suitable man- (Figure 3). An annulus 7) (also shown on ner by means of a flexible connection from the Figure 8) supports the small end of the truncone c and the rigid assembly comprising the cated cone C and is held by the tabs 0. As

will be obvious upon inspection of Fig. 2, magnet 6 represents the magnetic circuit, the central pole piece N having an energizing field coil 5. The suspension member P may be bolted or otherwise secured in spaced manner to the pole end Q of magnet 6, if desired, by bolts or screws such as 1, 3, the presence of the latter affording adjustment of the inner ends of both cones by adjustment of the suspension member P.

By suitably proportioning and otherwise providing adjustment of the suspension members X connecting the two cones or diaphragms it will be seen that the large cone 0 can be made to respond only to the low frequencies and to remain substantially unaffected by high frequencies of small amplitude. Such an arrangement results in the production of a loud speaker or electro-dynamic microphone having two ranges of response and as compared with known apparatus having but one conicalmembra-ne or diaphragm as at present in common use: constitutes an important inprovement.

It is to be understood that the invention is capable of numerous modifications other than those described and illustrated by way of example. p

Having now fully described my invention, I claim:

1. An acoustic apparatus comprising a support, a moving coil, means for producing an electro-dynamic action upon said coil, a plurality of truncated conical membranes located within the said support, said membraneshaving different dimensions, one of said membranes being partly coextensive with and spaced within the other and associated with the said coil, elastic suspension means upon each of said membranes connected to another element of said apparatus and elastic suspension means connecting one of said membranes to the other.

2. An acoustic apparatus comprising a support, a moving coil, means for producing an electro-dynamic action upon said coil, a plurality of truncated conical membranes located within the said support, said membranes having different dimensions and facing in the same direction, one of said membranes being partly coextensive with andspaced within the other and associated with the said coil, elastic suspension means upon each of said membranes connect-edto another element of said apparatus and elastic suspension means connecting one of said membranes to another.

3. An acoustic apparatus comprising a support, a moving coil, means for producing an electro-dynamic action upon said coil, a plurality of truncated conical membranes located within the said support, said. membranes having different dimensions, one of said membranes being partly coextensive with and spaced within the other and associated with the said coil and an elastic connection between the edge of a smaller to a circle on the surface or" the truncated cone of a larger membrane and intermediate the ends thereof, elastic suspension means on each of said membranes connected to another element of said apparatus.

4. An acoustic apparatus comprising a support, a moving coil, means for producing an electro-dynamic action upon said coil, a plurality of truncated conical membranes located within the said support, said membranes having different dimensions and being partlycoextensive and spaced apart, one of said membranes being associated with the said coil. elastic suspension means connecting one of said membranes to another, elastic suspension means connecting the large end of the largest membrane to the support, and elastic suspension means connecting the small ends of the truncated conical membranes to the support, said small ends of said latter members terminating in practically the same plane.

5. An acoustic apparatus including the combination, with a support, a movable coil, means for producing an electro-dynamic action of said coil, of a plurality of truncated conical membranes disposed in spaced relation and having different dimensions, one of said membranes being partly coextensive with another and associated with the said movable coil, elastic suspension means connecting the larger periphery of said one or small membrane to a larger membrane, elastic suspension means connecting the larger periphery of said larger membrane with the support, and a suspension member cut from a sheet of elastic material interconnecting said support and the smaller ends of the membranes.