Patent GB-190425101-A (GB)
Title: Improvements in Automatically Operated Musical Instruments
Inventor: SMITH IRVING BELL
Filed: 1904-11-18
Granted: 1905-01-19
Abstract: 25,101. Smith, I. B. Nov. 18. Automatic instuments.-An apparatus for mechanically playing keyboard instruments from tune-sheet records is described as applied to an electrically actuated pianoforte, but parts of it are applicable also to pneumatically-actuated instruments. The apparatus is ot the kind in which the closing, through perforations in the tunesheet, of the circuits of electromagnets c, Fig. 17, causes shoes b, connected to the keys e and to the armatures of electromagnets, to be moved into contact with a revolving drum and carried forward by friction. The drum and electromagnets are placed in the lower part of the case of the pianoforte, and the tunesheet rollers and circuit - closing devices are carried by a frame which is hinged so that it can be swung beneath the keyboard when not in use. This part of the apparatus is shown in plan in Fig. 8 and in side elevation in Fig. 11. The frame consists of steel plates 28, 29, united by a curved cast - iron back-plate 30 and by tie-rods 31, 32. A shaft 35 journals in lugs 33, 34 attached to the plate 30, and also in lugs 36, 37 formed in one piece with a base casting 38, secured to the underside of the keyboard A of the piano. To lock tbe frame in either of its positions, bolts 43, 50 are pressed into holes 44 or 45 in the frame by springs 42, 49, which act against lugs 41, 46 fixed to the base 38 and against pins on projections 40, 47 attached to the bolts. The bolts are withdrawn by means of a rod 39, formed in one piece with the bolt 43 and connected to the bolt 50 by a lever 51 passing through slots in the bar and bolt. The delivery roll (not shown) for the music sheet is provided on the inner face of the end flanges with a thick soft washer of felt at cne end and with a thin washer of felt or rubber at the other, and is mounted so as to be capable of a slight longitudinal movement to facilitate rewinding of the sheet. For this purpose, a frame 56 pivoted at 57 has at one end 59 a yieldingly-mounted socket bearing 61, and at the other a slotted socket bearing 62 provided with a driving-pulley 63, each to receive one end-pin of the delivery roll. From the delivery roll, the music sheet passes between a roller (not shown) having guide-flanges 185 and a rubber roller 186, mounted on pivoted arms 187, and thence over a metal contact roll 120 to the take-up roll 65. This roll is of sheet steel, bent to form an open butt tube, closed at the ends by cupshaped pieces 66 of reduced diameter, so that the edges of the tune-sheet do not touch the roll in winding. Within the roll 65 is pivoted a hook 67, Fig. 18, to receive a ring 68 on the end of the tunesheet, and a spring 73 tends to press the hook outwards through a hole 69 in the roll. A depressed tapering tongue 70 allows the hook and ring to be pulled below the surface of the roll by the tension of the tune-sheet, during winding. The hook is so shaped that the ring will slip off without aid when the sheet is completely unwound. At the ends of the roll are journal pins having conical holes to receive two pointed bearings carried respectively by the plate 29 and a bridging-strap 77. A wormwheel 78, attached to one end of the roll 65, gears with a worm 79 on a hollow shaft 80. At one end, the shaft has a plug of steel 81 forming a cone for a ball bearing, the cup of which is formed in the bent end 90 of an arm 91, pivoted at 92. A shaft 83 sliding in the shaft 80 has a pin 94 projecting through a slot'93 in the latter shaft, and carries a friction-wheel 84. Recessed in this wheel is a steel cup forming the ball race of a ball bearing, the cone of which is carried in one arm of a U-shaped steel strap 87, attached to a bar 88 pivoted at 89. The end of the bar 88 passes through a slot 102 in the plate 28, and is connected by a link 99 with a lever 96, provided with a pointer moving over a scale 154 and with a handle 98. A spring within the shaft 80 tends to press the shaft 83 outwards. The edge of the disc 84 forms a spherical surface concentric with the ball race in the disc, and bears against the surface of a pulley 101, driven from the motor and preferably recessed to receive a facing of leather or other suitable material. By moving the handle 98, the disc 84 is moved over the surface of the pulley 101 to vary the rate of winding of the music sheet. In order to rewind the sheet on the delivery roll, the arm 90 is rocked so that the worm 79 is disengaged from the wheel 78 and comes into mesh with a wheel 109, geared by a belt and pulleys with the delivery roll. This movement is effected by means of a handle 108, fixed to a lever 105, which carries a hook 107 adapted to engage and lift a pin 104 carried by a projection from the arm 91. On reversing the lever 105 to the position shown in Fig. 11, the spring end of the hook depresses a shoulder piece on the arm 91, and, as soon as the worm 79 meshes with the wheel 78, a dog 114 moves against a stop pin 115 and acts as a latch to prevent accidental disengagement of the worm and wheel. On the lever 105 are formed teeth 116, gearing with teeth on a sector 117. A shaft is rigidly attached to the sector 117 and to arms 119 carrying the metal contact-roll 120, so that, when the lever 105 is rocked to rewind the sheet, the roll 120 is moved out of contact with the brushes 121. Adjustment for wear of the brushes can be made by removing the lever 105 and replacing it so that the teeth 116 mesh with the sector one or two teeth in advance of their former position. By the side of the lever 96 is an insulated bar 122. A slight side movement of the lever completes a circuit through a battery, the casing of the machine, bar 122, and the electromagnet 123, Figs. 11 and 17. The pulley 101, which forms the armature of the electromagnet, is then raised out of contact with the friction disc 84, and the winding ceases. The casing 125 of the electromagnet 123 is cast in one piece with the base casting 38, and the core 126 consists of a steel sleeve, grooved internally to form races for ball bearings of the hollow spindle 129 of the pulley 101. A ball 132, seated in the cup-shaped ends of a screw 133 and spring plug 131, forms a thrust block bearing for the spindle. To prevent the pulley 101 from dropping out when the disc 84 is removed from it, by the swinging back of the roll-holder uoder the keyboard, the spindle may be grooved to receive the end of a screw, which does not touch it when in use. The selector or contact fingers 121 are mounted in transverse holes in a round wooden bar 136, and consist each of a number of phosphor-bronze fingers arranged in a line parallel to the length of the sheet, and provided at their upper ends with metal sleeves 137 in which are binding-screws 151. The brush-stick is partly enclosed by two curved strips of metal 138, the ends of which are attached to plugs 139, one at each end of the bar, which extend in reduced diameter through the side-plates 28, 29. A curved projecting strip 141, attached to one of the plates 138, terminates above the curved shield 148, protecting the brush-stick, in a handle 142 and a pointer moving over a scale 152. The stick 136 and brushes may be adjusted during playing by turning a milled head 145, on the shaft of which is a toothed wheel 144 gearing with a rack 143 on the plug 139. The wires connected to the contact-fingers are formed into two cables 149, 150, wound around the shaft 35 in opposite directions and passing to the action magnets c, Fig. 17. On the front edge of the shield 148 is a scale (not shown) which co-operates with zig-zag lines on the music sheet to indicate the movements to be imparted by the performer to the handle 98 and to a handle 157, which controls the loudness of the notes and is provided with a pointer 158 over a scale 155. The handle is attached to a bent lever 160, having at its end a roller taking under a lever 162. At the end of this lever is a stud 164, which rests on three or more levers 23, 24, 25, Figs. 8<a> and 2, controlling the loudness of different parts of the scale. The levers 23, 24, 25 are pivoted at 26 under the keyboard and connected by links 23<a>, 24<a>, 25<a> to arms 10, 14, 17, fixed respectively on a shaft 8, sleeve 12, and shaft 15. The shafts and sleeve are mounted in brackets 4, 5, 6, 7 inside the casing of the piano, and carry arms 9, 13, 16 supporting a rail against which the hammer shanks 22 rest. The rail is composed of two portions 18, 19, fitting over reduced portions of the arms 9, 13, 16, and lap jointed at the middle arm 13. The depression of one of the keys 27, which is resisted by a spring, serves to lengthen the stroke of the hammers towards the middle or either end of the scale, and the movement of the handle 157 forwards lengthens the stroke of all the hammers at once. At the side of the rollholder, Fig. 8, is a lever, provided with a handle 174 and connected by a link 177 to the upper end of the armature 167 of an electromagnet 165. The armature 167 is pivoted at its lower end and carries a bridge-piece 169, which, when the handle 174 is pushed backwards, connects contact-strips 170, 171 and closes the circuit of the motor. It will be seen from Fig. 17 that the current through the contact-fingers 121 passes through the series winding of the field magnets of the motor, thus increasing the torque with the load on the motor. When the end of the piece to be played is reached, a special perforation in the sheet allows an additional contact-finger 166 to touch the roll, thereby completing a circuit through the electromagnet 165, which attracts its armature 167 and opens all the circuits.