United States. Patent Office · Washington, D.C., Govt. Print. Off. · leaf 618
intain the unwinding of said spring at auniform speed, a friction disk mounted uponsaid shaft, and a friction lever controlled bya thumb screw adapted to be brought intoengagement with said friction disk to adjust the speed of unwinding of said spring, sub-stantially as described. In testimony…
Phonograph · Patents
Internet Archive · Smithsonian Libraries · Public Domain Mark 1.0. Free to use for anything.
![An illustration from [Graphophone patents], 1878, leaf 618](https://img.insideoutlibrary.com/img/1024/ia-graphophonepaten02unit-618-263.webp)
