(EN) 232,064. Hofmann, J. May 26, 1924. Recording m u s i c .- In electrical apparatus for recording the touch employed in playing the pianoforte, a rocking frame extends under some or all of the keys and rotates to various extents a contact drum which meets a gradually increasing spring resistance and is eventually stopped and returned thereby. Preferably one frame 4 extends under the treble, and another under the bass, key 5, the frames being pivoted as at 2 and each carrying an arm 6 which by a band 7 or toothed segment rotates a pulley 8 and the contact drum 12. In the path of a pin 14 on the drum are a number of spring-controlled arms a<1> - -- a<11>, which as thev successively come into action cause a gradually increasing resistance to the movement of the drum. In order to prevent, after a heavy blow, too rapid return of the drum under the spring action, the pin 14 is connected to the piston of a dash-pot 16, which has a tapered slot in its cylinder so that its effective braking-action is greater the greater the pistonstroke, thus ensuring closure of the electric contacts for a sufficient length of time to enable the recording elements to function. Each frame operates four recording devices, the contacts on the drum being arranged in various combinations.
