US2473897A - Electrical musical instrument - Google Patents

Description

June 21, 1949. L, MgLLER' 2,473,897

ELECTRICAL MUS ICAL INS TRUMENT Filed April 4, 1947 v ZShets-Sheet I e E3 Er W d E v i Q 3 f 4:0 H C T g d g g (D k 9 C9 W A b g (I):

June 21, 1949. I

Filed April 4, 1947 s. L. MILLER ELECTRI CAL MUS ICAL INSTRUMENT 2 Sheets-Sheet 2 Patented June 21, 1949 UNITED STATES PATENT OFFICE Application April 4, 1947, Serial No. 739,381 In Great Britain April 26, 1946 4. Claims. 1

This invention relates to electrical musical instruments of the organ type, in which the notes are produced in response to the action of light on a photo-electric cell, the light being caused to pass from an electric lamp or lamps to the cell through a pair of screens, one of which is stationary and the other is rotated.

In such an organ the lamp circuits are under the control of the keys of the key boardor boards and the various stops used in the organ. Depression of any key causes the corresponding lamp or lamps to be lit, and the light received therefrom after passing through the screens excites the associated photo-electric cell which controls an electronic amplifier and loud speaker for giving the required note.

The invention has for its object to provide an improved arrangement of screens and cells.

The invention comprises an organ unit having four pairs of rotary and stationary light controlling screens arranged in quadrilateral dispositlon.

Also the invention comprises the combination with screens as specified in the preceding paragraph, of photo-electric cells so disposed that each can receive light through the adjacent parts of two pairs of screens.

In the accompanying. drawings, Figure 1 is a diagrammatic plan view of an electric organ unit embodying the invention. Figure 2 is a front elevation illustrating diagrammatically one of the fixed screens.

Figure 3 is a fragmentary view illustrating to a larger scale than Figures 1 and 2 portions of an associated pair of (fixed and rotary) screens.

Referring to the drawings, the unit comprises four rotary transparent screens a arranged with their rotation axes at right angles as shown in Figure 1. Within the assembly is arranged a gear box I) from which extend at right angles to each other the spindles connected to the screens a. The gearing in the box receives motion from an electric motor or any other convenient source (not shown), and the gearing is such that the spindles c are driven at appropriate and different speeds.

In front of each rotary screen a is mounted an opaque fixed screen d, and the screens are mounted in any convenient housing e. On the housing and in front of each pair of screens are mounted banks of lamps f and behind the rotary screens are mounted four photo-electric cells g 50 arranged as shown that each can receive light through adjacent parts of two pairs of screens.

Each rotary screen a has formed on its con- 2 centric rings of opaque wave patterns corresponding to a particular note and its octaves. Supposing for example that one of the discs has a wave pattern corresponding to the note middle-C, it will also have on its other rings corresponding to the octaves of this note, the number of rings corresponding to the number of octaves to be provided in the organ. In addition other rings are included. The pitch of these also corresponds to the different octaves, but their patterns differ and correspond with notes of different character. In Figure 3 is shown a portion of a screen a, with a portion of one of the wave pattern rmgs h.

In each fixed screen d are formed rings of slots These rings coincide with the wave pattern rings on the associated rotary screen. The number of slots in each ring corresponds with the number of associated lamps required to be lit simultaneously under the control of the organ stops or other controls when a key is depressed. The lamps f in front of each fixed screen are also arranged in rings: corresponding to the rings of slots, and the number and spacing of the lamps in each ring corresponds with the number and spacing of the slots in the associated ring of slots. A portion of a fixed screen (1 and one slot 2' are shown in Figure 3. A lamp 1 is also represented by the dotted circle around the slot.

The slots and Wave patterns may be such as will have the same effect on the light emitted from the lamps as the well-known pin-hole device used in some forms of photographic cameras, the light being thereby focussed on to the cells. Alternatively an additional fixed screen may be arranged between the lamps and the fixed screens at, the additional screen being suitably perforated to produce the desired pinhole effect. Or any usual arrangement of lenses may be mounted between the lamps and the fixed screens for focussing the light on the cells.

Instead of using in each pair of screens an opaque fixed screen with slots, and a transparent screen with opaque wave-patterns, the reverse arrangement may be used. In this case the opaque wave-patterns are formed on a transparent fixed screen, and the slots are formed in an opaque rotary screen.

The effect of relative rotation of the fixed and rotary screens is to cause the light transmitted to the associated cell or cells to fluctuate in a manner corresponding to the desired notes to be sounded. The cells are connected to a current amplifying system and loud speaker in the usual manner.

As shown in Figure 1, each unit comprises four pairs of screens at right angles to each other, four cells arranged so that each can receive light through the adjacent parts of two pairs of screens, and banks of lamps situated in front of each pair of screens. Three such units are employed to form an organ. Each pair of screens corresponds to a particular note and its octaves, and the twelve screens of the three units provide the required usual series of twelve notes in the octave, namely, 0., C sharp, D., D sharp A., A sharp and B.

The complete organ consists of two component organs, namely a great and a swell, and the arrangement above described of the photo-electric cell 9 enables each unit to serve both organs. Thus, starting with the lower screens and lamps in Figure 1, the right-hand half forms part of the great organ. Proceeding now around the figure in the anti-clockwise direction, the succeeding halves of the different screens and lamps form parts of the great, swell, swell, great, great, swell and swell respectively, the last being the left-hand half of the lower screens and lamps.

The mode of operating the lamps under the control of the key stops, pedals, or other usual controls, and the mode of utilising the excitations of the photo-electric cells for actuating the amplifier and loud speaker form no part of the present invention. But the following brief description may serve to elucidate further the purpose of the units above described. With the rotary screens in motion, the depressing of the keys on the key board causes the corresponding lamps to light. The number of lamps thereby brought into action opposite any ring of slots depends on the particular stops or other controls in use. The eiiect of the light from a number of associated lamps on the same wave pattern is to cause a corresponding excitation of the associated cell, the minimum excitation being obtained when a single lamp is brought into action. By the use of appropriate stops, a number of different wavepattern rings corresponding to the same note may be illuminated simultaneously for obtaining a note of the required composite character, the range of dilferent character available being dependent on the number of different wave-patterns of the same note provided on the one screen.

Octaves of a given note are obtained by illuminating the corresponding rings of wave-patterns.

By this invention great simplicity and compactness with the desired tonal control are obtainable in a very convenient manner.

Havin thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. In an electrical musical instrument of the type specified, the combination of an assembly of four pairs of rotary and stationary light controlling screens arranged at right angles to each other in the form of a quadrilateral figure with the screens of each pair situated one behind the other, and with one of the pairs of said screens at each side of said figure, a plurality of light sources arranged outside the screen assembly in association with each pair of said screens, and lightresponsive members arranged within said screen assembly so that each such member is exposible through adjacent parts of two pairs of said screens to light emanating from the corresponding light sources.

2. In an electrical musical instrument according to claim 1, means located within the screen assembly for rotating the rotary screens.

3. In an electrical musical instrument according to claim 1, a gear box located within the screen assembly for transmitting motion to the rotary screens at different relative speeds.

4. In an electrical musical instrument according to claim 1, banks of lamps constituting the light sources at the outer side of each pair of screens, each bank of lamps being arranged in circular formation and concentrically with the other banks at the outer side of the same pair of screens.

STANLEY LEONARD MILLER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,819,820 Kent Aug. 18, 1931 1,848,222 Potter Mar. 8, 1932 2,014,741 Lesti Sept, 17, 1935

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