Gear's illustrated catalogue of wood and iron working machinery (1872)
A.S. Gear, Gear, A. S · Boston : Printed at A.S. Gear's printing office, 62 Sudbury Street · leaf 398
ction with Patent No. 5, groups the strings in three different divisions. Bylengthening the bridge in the shape of a ring to the middle of the sounding-board, the problem was solved of bringinglarger surfaces of the board into vibratory action. Only a thorough knowledge and careful calculation of… … £-S OILLER X.A H shows the cupola iron frame, with patent ring bridge, as used in upright pianos. The compression screws pressthe sounding-board against the metal frame ; the latter rests, without any intermediate bushing, directly upon the board,and descends at certain points between the braces of…
