Patent GB-190710543-A (GB)
Title: Improvements in Piano Violins and like Stringed Musical Instruments.
Inventor: LAKEF HAROLD WILLIAMSON
Filed: 1907-05-06
Granted: 1908-05-06
Abstract: 10,543. Lake, H. W., [Popper & Co.]. May 6. Instruments with sonorous strings ; pianofortes ; automatic instruments.-The strings of an instrument resembling an upright piano are brought into contact with a bowing-device by displacing the bridges on which the strings are mounted. The instrument may be provided with a keyboard for manual operation, or it may be operated mechanically, electrically, or pneumatically, in which case the keyboard may be retained, or dispensed with. In the instrument illustrated in Figs. 1 and 3 in sectional elevation and plan respectively, two sets of similarly tuned strings 2 are arranged vertically over the curved faces of a sound-box 1. The tuning-pins for both sets of strings can be operated from the front of the instrument. An endless belt 7 passes over a driving-roller 8 and an adjustable tensioning-roller 9 and over two series of guide-rollers 22. The curvature of the faces of the sound-box increases towards the bass end, so that the belt presses more heavily on the bass than on the treble strings. The roller 9 is positioned by means of a knee lever 16, the end 17 of which is hinged to fold up when not required ; the minimum tension of the belt is regulated by means of a screw-stop 21. The belt is arranged in an oblique position to obtain the best effect ; it is composed of lengths of horsehair, with knots at the back of the belt, arranged on two or more relatively displaced groups so as to present a continuous surface. A block 27 of resin is pressed against the belt and is rotated, so as to wear uniformly, by means of a rod 32 operated from the driving-shaft 13 and acting eccentrically upon the block of resin. The movable bridges 48, Fig. 9, are notched for the reception of the strings, and slotted for the passage of the connexions 44 by which they are operated in pairs ; they are mounted upon stationary notched members 34 with their knife-edge bearings parallel to the strings. Each member 31 has two arms, of which one is secured to the sound-box while the other is connected by a soundpost 50 to the opposite wall of the sound-box. The bridges are connected directly to the arms 41 of the keys 40. A set of pedals 51 is provided for the bass notes, the pedals being connected to the corresponding keys ; the pedal frame can be folded up into a vertical position. Padded rails 61, 68, connected with a draw-stop 62, may be applied to the strings for the production of harmonic tones, or one rail only may be provided. The strings in their inoperative position may rest upon a damper rail, and this rail may be padded at intervals corresponding to the spacing of the strings, so that the damping effect may be eliminated by shifting the rail. A vibrato effect may be produced by means of a padded rail which can be suitably oscillated to act upon the sounding strings in either the active or the inactive portion of their length. The movable bridges may be arranged midway of the length of the strings, and in this case both halves of each string may be sounded by means of separate bowing-devices. Motion is transmitted to the driving-shaft 13 through a belt 12 and shaft 10 from a double clutch gear 81 connected to sleeves 77, 78 and bow-drill mechanism operated from a single treadle 11, the belt being driven constantly in the same direction.