Patent search ap:("BELL TELEPHONE LABOR INC") AND inv:"KING JOHN H" Page 2

11.

发明授权
Phonograph reproducer 失效

公开(公告)号：US1918972A

公开(公告)日：1933-07-18

申请号：US50182430

申请日：1930-12-12

Applicant: BELL TELEPHONE LABOR INC

Inventor： KING JOHN H

IPC: H04R1/16 , H04R9/12

CPC classification number: H04R1/16 , H04R9/12

Patent Agency Ranking