GB506421A - Improvements in electro-dynamic loud-speakers - Google Patents

Abstract

506,421. Loud - speakers ; electromagnets. GIALLULY, M. S. DE, MACE, J., PAZ, A., CERF, (nÚe SCHLADT), E., SCEMAMA, L., ROBERT, P., GORY, M., and VILLARON, R. Aug. 26, 1937, No. 23416. Void. Convention date, Sept. 10, 1936. [Class 40 (iv)] [Also in Group XXXV] In a moving-coil loud-speaker comprising an electromagnet for producing the magnetic field and/or speech-coil transformer, the cores of the electromagnet and of the transformer are structurally combined so as to form an uninterrupted magnetic circuit. As shown, the core of the electromagnet comprises E-shaped laminations 25 forming the core 28 of the transformer. The primary and secondary windings 29, 30 of the transformer are mounted on the core 28 and the magnetic circuit of the loud-speaker is completed by a cylindrical polepiece 22 and a pole-plate 10. The core of the transformer which may be formed of U-shaped laminations may be closed by a laminated member which does not form a part of the core of the electromagnet, but is magnetically connected thereto. The housing 1 for the diaphragm 5 is connected to poleplate 10 by screws 12 and the cores are enclosed by a cylindrical casing 36 and a disc 35, the terminals of the loud-speaker being mounted on the casing or on the disc. The core of the transformer may be closed by a, member attached to, and magnetically insulated from, the core of the electromagnet or the transformer may be mounted on the housing 1. The core of the electromagnet may be U- shaped and a transformer with a laminated core may be associated with a permanent magnet.