US 2013792 A
Description (OCR text may contain errors)
Sept. 10, 1935. sc A E 2,013,792
S EAMLE S S DIAPHRAGM Filed Jan. 9, 1934 IN VENT OR Efi/CH SCH/15 65 A TTORNEY byfibrousmaterlal.
Patented Sept. 10, 1935 UNITED STATES PATENT OFFICE SEAHLESS DIAPHRAGM Erich Schlfer, Berlin, Germany, aaaignor to Telefunken Gesellaehaft fur Drahtloae Telegraphic, Berlin. Germany, a corporation of Germany Application January 9, 1934, Serial No. 705,838 In Germany February 8, 1983 3 Claims. (Cl. 181-82) This invention relates to diaphragms for acoustic apparatus and the like. The object of the invention is to provide a seamless diaphragm made, from fibrous material, preferably cast 5 carton-for acoustic WW.
Diaphragms of fibrous material are fund mentally known in the prior art. However, while these diaphragms are quite serviceable in practice, they nevertheless suffer from the drawback 10 that they lack sumcient rigidity for high or heavyduty requirements in acoustical work. According to the invention thesedrawbacks are obviated by placing reinforcement ribs or fins or stiffening skeletons of refined and alloyed light metal (alu- 15 minum or beryllium alloys) or other hard and light substances in the mold during the process here disclosed being applied to a cone diaphragm. The fins or ribs or reinforcement members being of plain or profiled form, are made of alloyed light metal and are indicated at I. They are embedded into the diaphragm consisting of 5 fibrous material 2.
What I claim is: i. The method of manufacturing a diaphragm Y which consists in molding a diaphragm of fibrous material around a reinforcingframe of rigid 6 material.
2. A diaphragm comprising a rigid reinforcing frame and a fibrous mass molded around said frame and formed into the desired diaphragm m 3. seamless diaphragm comprising a reinforcing skeleton of a light metal alloy and a molded fibrous material surrounding said'skeleton sothatsaidskeletonisimbeddedinsaidfibrousmaterial, aaid fibrous material being formed into so