Magnetically operated sign
作者： Maurice K Taylor
DOI:
关键词:
摘要:
lens.org 参考文章(7)
Skrobisch Alfred, Electrically controlled magnetic movement ,(1955)
John E Johnson, Vacant-seat detector for theaters. ,(1916)
James Priestnall Naylor, Apparatus for displaying advertisements, signaling, and the like. ,(1911)
Knight Milton A, Taylor John A, Electrical indicating device ,(1950)
John R Knight, Electromagnetic display device ,(1958)
Ludwig J Bloechl, Changeable indicators for display devices ,(1959)
Walter H Campbell, Electrical drop signal device ,(1944)