Patent GB-393672-A (GB)
Title: Improvements in automatic musical instruments
Filed: 1931-12-16
Abstract: 393,672. Automatic musical instruments. ILES, G. B., Gap House, Broadstairs, Kent. Dec. 16, 1931, No. 34902. [Class 88 (i).] In automatic musical instruments, of two preferably adjacent tracker - bar note-holes uncovered by perforations in the tune-sheet, the second acts to control the loudness of the note played by the first, and will itself only play a note if also required. Thus notes are played simultaneously at different pressures, no matter where they are located in the compass of the instrument. In the tune-sheet, Fig. 2, perforations 2, 2a sound notes which are accented (or softened) by the perforations 3, 3a, perforations 1 yielding normal notes. For each note-hole b, Fig. 1, in the tracker-bar a there are chambers i, d, j, d<1> and e, chambers i, d and j, d<1> being respectively separated by membranes h, h<1> coacting with tubes f, g which are connected with the chamber e and extend into .the chambers d, d<1>. The tracker-tube m is divided, branch m<2> being connected to the chamber i corresponding to the next note-hole on the bass side. Branch m<1> is connected through the chambers d, d<1> and a tube n to the valve selecting the degree of vacuum to be applied to the striking- pneumatic valve of the next note on the treble side. Chamber e is connected by a tube o to the striking-pneumatic valve pertaining to the particular note-hole b. All the tubes and chambers in Fig. 1 normally contain vacuum except the chambers j which are connected together by a groove y and contain atmosphere. A single tune-sheet aperture 1 performs three functions, the sounding of its note by a pulse passing by m<1>, d, f, e, o to the striking-pneumatic valve being alone effective; since the pulses passing along m<2>and n merely actuate the membrane h and the selector valve of notes, respectively on the bass and treble sides, for which there are no corresponding tune-sheet perforations. With two perforations 2, 3, however, perforation 2 sounds its note similarly to the perforation 1 ; but perforation 3 automatically becomes an expression perforation operating, through its tube n, the selector valve of perforation 2, and being prevented from sounding its own note by the closure of its tube f by the pulse through m<2> from perforation 2. If it is desired that perforation 3 should also play a note, the membranes h<1> are removed from tubes g by a valve which controls the groove y and is operated from a special hole in the tracker-bar. The pulse from perforation 3 then reaches its own striking-pneumatic valve by m<1>, d, d<1>, g, e, o, irrespective of the fact that membrane h is closed by perforation 2. Figs. 3 and 4 (not shown) illustrate alternative forms of single-acting selector valves controlling the high tension and having a flap valve in the low tension supply, chosen according .as to whether it is desired to soften or to accent by means of the control perforations 3. In Fig. S (not shown) the selector valve is double-acting, lying between the low and high tension supplies. In Figs. 5 and 6 (not shown) the branch m<2> is replaced by a duct connecting the chamber e with the chamber i of the next note on the bass side. In this construction an exposed notehole can only cancel the playing power of another note-hole when it is permitted to sound its own note, i.e. a control perforation 3 having had its playing powers cancelled by noteperforation 2 cannot in turn cancel the noteplaying powers of the next hole on its bass side. A note may be accented or softened to any intermediate extent by proportionately setting back the control perforation 3 relative to the perforation 2, so that the full effect of the change over of the vacuum is not produced ; by this means only a single common windway, with one degree of tension, is necessary, Fig. 7 (not shown). In this construction when the chest is made very compact, small leaks from the high tension to the vacuum chambers of the striking-pneumatic valves may be provided, to prevent soft notes from failing to sound ; or a spring-loaded reserve bellows may be attached to each chamber. Figs. 9 and 10 (not shown) illustrate additional valves for use with the " chimney " valve shown in Fig. 1 of Specification 364,035, which valve then acts as a combined selector and striking-pneumatic valve. Fig. 11 shows the lay-out of an electro-pneumatic action. Each duct from a note-hole in the tracker-bar operates by a diaphragm a set of three contacts A, B, C of which contacts A, B are normally open and C closed. On exposure of a note-hole, say of note 2, contacts A<2>, B2 are closed and C<2> opened, and the striking. pneumatic valve S<2> is electrically 'or electropneumatically operated to sound a note provided contact C<3> has not been opened by exposure of the note-hole of note 3. If, however, the note-hole of note 3 has also. been exposed, note 2 is prevented from sounding, but by the closing of contact B<2> the selector valve P of note 3 is operated, thereby changing over the 'vacuum of the note (3) then sounded. Fig. 12 (not shown) shows a modified lay-out for use with " chimney " valves.