GB324971A - Improvements in bow control device for stringed musical instruments - Google Patents

Abstract

324,971. Dehn, F. B., (Mills Novelty Co.). Nov. 6, 1928. Keyboard stringed instruments; bows.- Stringed musical instruments of the viol class with electrically operated fingering devices are provided with expression-controlling electromagnets in circuits including resistances controlled by pedals or other means to vary the energization of the magnets and so the pressure of the bows on the strings. Resistances in the circuit of a bow-driving electric motor are also controlled to vary the speed of the motor and so of the bows. Each bow 37, Fig. 1, is arranged on a shaft 36 continuously rotated by a motor 11 common to all four bows. Energization of a magnet 7 depresses a sleeve 44 surrounding the shaft 36 and so presses the bow 37 on to the string 38, a spring 39 raising the shaft 36 in its guide 45 when the magnet 7 is de-energized. In a keyboard instrument, Fig. 4, each key 8 closes the circuits of the magnets 6 controlling the finger - ing devices and of one of the bow-magnets 7. The motor 11 is continuously in circuit during playing of the instrument and is prevented from attaining too low a speed by a governor 13. Tapped resistances 15, 16 are arranged respectively in the circuits of the motor 11 and magnets 7 and are controlled by soft and loud foot-pedals 31, 25. The pedal 31 normally short-circuits a section of the resistance 15 and, when the pedal 31 is depressed, this resistance is thrown into the motor circuit. The pedal 25, when depressed, short circuits successive sections of both resistances 15, 16 to increase the pressure and speed of the bow. The pedals 25, 31 are depressed against the action of springs 55, Fig. 2, and carry contacts 26, 27, 58 passing over fixed resistance contacts 17, 18, 32. Each of the pedal contacts comprises a spring-pressed plunger in a tube 60 with a cap 61 for the electric connection. The pivotal movements of the pedals are limited by stops 56, 57.