Patent GB-191404336-A (GB)
Title: Improvements in and relating to Automatic Musical Instruments.
Inventor: COLLEN ROBERT HENRY
Filed: 1914-02-19
Granted: 1915-02-19
Abstract: 4336. Collen, R. H. Feb. 19. P l a y e r - p i a n o s ; actions; blowing and exhausting air; winding - mechanism. - A pneumatic action of the piston-and-cylinder type, occupying but little space and adapted therefore to be fitted in a readily removable manner in the casings of upright pianos, is operated directly from the tracker ducts, no intermediate valves being employed. The pistons are fitted with ball relief valves to secure a quick return movement when the tracker duct is closed. The pumping. regulating, and expression-controlling devices are also of the piston-and-cylinder type. In the form of action shown in Figs. 3, 3<a>, and 3<b>, the cylinder n above the long hollow piston o is in permanent connexion with the exhaust trunk g, while at its lower end it is connected through a side pipe s and passages x, y, z with a duct of the tracker-bar, suction being also admitted at this end by a side pipe t and bleed-hole v. When the tracker duct is opened, the piston o rises and actuates the piano wippens through a stirrup 8, to which the piston is connected by pins projecting through slots 7 in the cylinder. The rise of the piston connects a passage 3 through a port 1 to the suction pipe t, and the suction lifts a hall 5 so as to close the passage. When the tracker duct is closed again, the first slight fall of pressure in the lower end of the cylinder, due to suction through the bleed-hole v, unseats the ball 5, and the space below the piston is then instantly exhausted through the passage 3, 'causing a quick return of the piston. The valve 5 may be omitted in instruments in which it is permissible for the piston to return immediately, without waiting for the end of the note slot to pass the tracker duct. In a modified arrangement, the pneumatic actions are arranged below the wippens. The action may also be modified to act by pressure instead of suction. The pumping-arrangements, shown in Fig. 8, comprise cylinders 60 with pistons 66 operated by flexible connexions 68 from sectors 69 on swing- ing arms 70, operated by links 75 and bellcrank levers from the treadles, which are of the usual folding construction. The pumping- cylinders communicate through valves 67 with a reservoir cylinder 51, having a piston working against an adjustably tensioned spring to regulate the degree of exhaust. The pumping- arrangements as a whole are mounted on a removable metal frame. The regulating and expression-control box j, Fig. 5, is mounted on the same batten f, Fig. 3. as the pneumatic actions. The bass and treble sections of the exhaust trunk g are controlled by adjustably tensioned piston regulating-valves 22, while expression effects are obtained by supplementary valve ports 28 controlled by pneumatic actions of the type shown in Fig. 3, these actions being controlled by valves operated by finger-levers, or automatically from the tune-sheet. The connexion between the tracker ducts and the pneumatics is through face-to-face junction boards. A multicylinder engine is preferably employed as the winding-motor.