Patent GB-191307320-A (GB)
Title: Improvements in and relating to Automatic Musical Instruments.
Inventor: LAST JAMES
Filed: 1913-03-27
Granted: 1914-06-29
Abstract: 7320. Last, J. March 27. Actions; tracker-bars; expression, controlling; tune-sheets.-Four sets of tracker-ducts are provided which are termed pilot, preparation, playing, and cut-off ducts respectively. The preparation ducts are arranged in parallel rows, and each row is associated with a membranepack comprising eighty-eight pairs of membranes, one for each note of the instrument, and other membranes and membrane-pairs controlled by the preparation ducts and adapted to select any one of the eighty-eight pairs of membranes bv a two-coordinate system of selection. The pilot-ducts are arranged in an inclined row, each pilot-duct being in alinement with the corresponding row of preparation-ducts. In playing a note, the opening of a pilot duct renders the corresponding row of preparation ducts operative. A combination of preparation ducts is then opened to operate valves for exhausting a pair of membranes to permit a valve, controlled by the playing-aperture, to admit air to operate a valve controlling the striking- pneumatic. Subsequently, a cut-off duct restores the parts to their normal positions. A playing-duct may control the sounding of any note in the whole compass. Two sets of playing-ducts may be provided for loud and soft notes respectively. Non- return valves or other pneumatic, mechanical, or electrical equivalents may be substituted for the membrane - pack. Fig. 3 is a view of the tracker-bar and tunesheet. The tracker-bar is provided with four sets of ducts a, b, c, d. The preparation ducts a are arranged in ten parallel rows, each row containing ten ducts. A cut-off duct b and pilot duct c are provided for each row of preparation ducts. Two playing- ducts d are provided for each row of preparation ducts, one for notes of normal loudness, the other for accented notes. Figs. 4 and 5 are views in cross-section and plan respectively of the portion of the primary tray corresponding to one row of preparation ducts a, single cut-off and pilot ducts b, c, and a pair of playing-ducts d. The ten ducts a control the valves 1-10, the duct b controls the valve 19, the duct c controls the valve 20, and the ducts d control the valves 18, 18<a>. Air-tight fabric may be used to cover channels such as 27. The primary tray controls membrane-boards, one of which is provided for each row of preparationducts a. Fig. 6 is a fragmentary view in crosssection of a number of membrane-boards, and Figs. 7 and 8 are diagrammatic elevations in different planes of the left and right hand ends of a membrane-board. Each membrane-board comprises two channelled plates 34 with a perforated distance-piece 35 between them, having a membrane 38 on each side of it. Eighty-eight chambers 39, corresponding to the eighty-eight notes of a piano, are thus formed and are arranged in eight groups 36 of ten each and one group 37 of eight, as shown in Figs. 7 and 8. All the chambers 39 in a group are connected together. The chambers 39 are normally at atmospheric pressure, so that the membranes 38 are pressed against the plates 34, and the longitudinal ducts 40-49 are normally disconnected from the transverse channels 51. The channels 51 connect with the diaphragmchambers 54 of the high and low tension secondary valves 77, 76 controlling the striking pneumatics 82, Fig. 9. The ducts 40 .. 43 and 45 .. 48 are connected by central ducts 50 with the outer surfaces of a membrane-pair in each of the groups 36, 37. The ducts 44, 49 are connected by central ducts 50 with the outer surfaces of a membrane-pair in each of the groups 36. Groups of single membranes 60-64 co-operate with two preparation ducts to select a particular group 36 or 37, and groups of membrane-pairs 55-59 also co-operate with two preparation ducts to select a particular channel 40-49. To play a note, a playing-aperture such as A<2>, two pilot apertures such as A<3>, A<5>, four preparation apertures such as 2, 5, 8, 10, and a cut-off aperture such as A<4> are provided in the tune-sheet. The pilot-aperture A' admits air to operate the valve 20, so admitting air to a channel 27 above the channels 28 and holding the non-return valves 29 upon the seats. The connexion between the channels 28, under the valves 1...10 and 19, and the exhaust-chest 21 is thus cut off, so that on the admission of air by the tune-sheet apertures 2, 5, 8, 10 to the corresponding channels 28, the valves 2, 5, 8, 10 are lifted. The corresponding pipes 22, which are connected with the pipes 2, 5, 8, 10 in Figs. 7 and 8, are therefore connected through the non-return valves 23 with the exhaust-chest 21. The groups 60, 63 are exhausted through the pipes 5, 2 to establish a connexion from the channel 30, through the pipe 32 and channel 71; past the membranes 73, 75, and through the channel w to the group 36 containing the membrane-pair z. The channel 30 is connected to exhaust through the non-return valve 31, and also by a channel controlled by the cut-off valve 19, so that all the chambers 39 in this membrane group 36 are exhausted. The chambers 39 in the membrane - groups 57, 55 are exhausted through the pipes 8, 10, so that, when the playing-aperture A<2> admits air to its tracker-duct A<1>, the valve 18, which is similar to the valves 19, 20, admits air to the pipe y and duct 70, past the membrane-pairs 67, 65, through the duct 41, past the membrane-pair z, through the duct 52, non-return valve 53, and transverse channel 51, to operate the high-tension valve 77 and sound an accented note. The same note of normal loudness would be sounded by an aperture admitting air to the tracker-duct A, so raising the valve 18<a> and admitting air through a duplicate set of pipes and channels formed in the other plate 34 of the membrane-board 33. If the same note is to be repeated, it is merely necessary to provide another aperture A<2>, but otherwise the pilot aperture A<5> admits air to operate the valve 20 again and admit air to the channel 27 so that the exhaustion of the channel 28 under the cut-off valve 19 ceases. The cut-off aperture A<4> then admits air to operate the valve 19, which admits air to the channel 30, through the non-return valves 31, pipes 22, and channels 2, 5, 8, 10 to recharge the membrane groups 63, 60, 57, 55. The rows of preparation ducts may be subdivided into two or more sections each containing a smaller number of ducts, a primary combination from each section being combined to obtain the required number of secondary combinations. The Provisional Specification describes a tune-sheet having three preparation apertures for each note. The striking-pneumatics may be operated by three or more tensions of wind controlled by three or more valves.