US3408448A - Magnetic keying for electronic organs - Google Patents

Description

Oct. 29, 1968 T. A. LAZZARO MAGNETIC KEYING FOR ELECTRONIC ORGANS Filed May 24, 1965 2 Sheets-Sheet 1 dpiaz zer'o Oct. 29, 1968 T, A. LAZZARO 3,408,448

MAGNETIC KEYING FOR ELECTRONIC ORGANS Filed May 1965 4 2 Sheets-Sheet 2 i6} I 'I 7111 a a I 111115111 1. Q I i w w T I PINMNM I @5 53 United States Patent 01' hoe 3,408,448 Patented Oct. 29, 1968 3 408 448 MAGNETIC KEYING FOR ELECTRONIC ORGANS Thomas A. Lazzaro, Amherst, N.Y., assignor to The glgrlitzer Company, Chicago, 111., a corporation of Filed May 24, 1965, Ser. No. 457,963 7 Claims. (Cl. 841.01)

ABSTRACT OF THE DISCLOSURE Magnetically operable pedal switches for an electronic organ wherein each pedal carries at its inner end a flat magnet polarized in the direction of the pedal. An encapsulated dry reed switch is spaced from the end of each pedal in alignment therewith, and magnetic symmetry holds the switch contacts open. Upon movement of the pedal, the magnetic circuit becomes asymmetric, and the overlapping ends of the reed switches are magnetically attracted into contact.

This invention relates to the electronic musical art, and more particularly to improved switching therein.

Heretofore, in electronic musical instruments, such as electronic organs, it has been conventional practice to provide switches in the form of one or more whisker-like contacts which are flexed upon depression of a key or pedal into contact with corresponding fixed collectors or stop rods. Such switches have been prone to deformation of the whisker-like wire contacts, particularly in the pedal switches wherein a person might inadvertently stand on a pedal and push it past its intended limit position. Furthermore, such prior art switch contacts have been open to the atmosphere, and this has tended to cause corrosion of the switch contacts, particularly upon the arcing or sparking thereof as contact is made and broken. Furthermore, and particularly in the case of pedal switches, there has been a tendency for dust to settle on the switches and to render switching action unreliable.

Accordingly, it is an object of this invention to provide a switch mechanism for an electronic musical instrument, particularly for the pedals of an electronic organ, overcoming the prior art difficulties noted above.

It is more particularly an object of this invention to provide key or pedal switches in an electronic musical instrument which are sealed from the atmosphere, and thereby substantially immune from corrosion and completely free from dust.

Yet another object of the present invention is to provide a switch mechanism for an electronic musical instrument which is impositively operated from the keys or pedals, thereby completely avoiding the possibility of bending contacts through over travel.

More specifically, it is an object of this invention to provide magnetically operated key switches in an electronic musical instrument.

Other and further objects and advantages of the present invention will be apparent from the following description when taken in connection with the accompanying drawings wherein:

FIG. 1 is a perspective view of an electronic organ embodying the principles of the present invention;

FIG. 2 is a fragmentary perspective view of the pedal board and associated switches, with the switch mounting board turned down from its normal position to show the switches.

FIG. 3 is a fragmentary top view of the pedal board;

FIG. 4 is a vertical sectional view through the pedal board as taken substantially along the line 44 in FIG. 3;

FIG. 5 is a fragmentary sectional view through the pedal board as taken along the line 55 in FIG. 3;

FIG. 6 is a fragmentary horizontal sectional view on an enlarged scale taken substantially along the line 66 in FIG. 5 and FIG. 7 is a vertical sectional view taken substantially along the line 7-7 in FIG. 6.

Referring now in greater particularity to the drawings, and first to FIG. 1, there will be seen an electronic organ 20 constructed in accordance with the principles of the present invention. The organ includes the usual case or housing 22 having a music rack 24 on the top thereof, and also having upper and lower manuals or keyboards 26 and 28, respectively. Various stop tablets 30 are provided for setting up different combinations of stops and for controlling various functions of the organ. There is also a swell pedal 32, and loudspeakers are provided behind grills 34. Suitable amplifiers, filters, etc. are all contained within the organ. Finally, and of primary importance in the present invention, there is a pedal board or clavier 36 of the type having a plurality of pedals 38 hinged to a support 40 at the rear thereof, and normally disposed substantially below the organists bench. The number of pedals 38 may vary, and for illustrative purposes the organ has been shown with two full octaves, with the upper and lower pedal being for the same note, i.e. a total of twenty-five pedals. It is also fairly conventional practice in electronic organs to provide but one octave plus one of pedals, i.e. thirteen. Obviously, the principles of the invention as hereinafter set forth apply equally well regardless of the number of pedals.

As may be seen in the remaining figures of the drawing, and first with particular reference to FIGS. 2 and 3, there is a facing board 42 (seen also in FIG. 1) secured to the support 40 by means such as boards 44 interspersed among the pedals and recessed there-below. The facing board is detachably secured to the organ case by means of right angle brackets 45 having forward projections 46 of a hook-like nature extending into slots in part of the organ case 48 and cooperating with suitable latch structure therein (not shown). The facing board 42 is provided with suitable horizontal recesses 50 through which pedal extensions 52 of reduced height extend. As may be seen in FIG. 3, vertical guide pins or studs 53 are disposed between the pedal extensions 52 and extend from top to bottom of the openings 50 to position the pedals laterally.

A plurality of blocks 54 is secured to the backside of the facing board 42 by means such as screws 56 relatively near the top and bottom thereof generally in substantial alignment with the supporting boards 44. A back or switch mounting board 58 is detachably secured to the blocks 54 by means of screws 60 passing through washers 62 and vertically elongated slots or large clearance holes 64 in the switch mounting board 58, the screws being threaded into the blocks 54 centrally thereof. At the left end (FIG. 3) the switch mounting board 58 is additionally secured by means of a sheet metal Z-shaped bracket 66 welded to the bracket 45 and having a sheet metal nut 68 thereon receiving a machine screw 70 pass ing through a washer 72 and one of the vertically elongated slots 64.

A plurality of switch assemblies or units 74 is spaced across the switch mounting board 58, each unit being in alignment with the extension or projecting end 52 of a corresponding pedal 38. Each switch assembly or unit, see particularly FIGS. 6 and 7, includes a dry reed switch 76 of the type comprising a glass tube or vial 78 and having a pair of contacts 80 extending thereinto in overlapping relation from the opposite ends of the tube in which the contacts or reeds 80 are sealed. The contacts are normally open, and are magnetically susceptible. Such switches are known in the art, and suitable switches include General Electric dry reed switch part number 2DR15 and Gordos dry reed switch part number MR900.

Each of the dry reed switches 76 is mounted by means of two wire forks 82. Each such fork comprises a shank 84 consisting of a doubled-over wire, generally in U form but with the legs contacting, plus an integral gripping end 86 wherein the wire ends are respectively formed into substantially semi-circular shape, with outwardly flaring tips 88. The shank 84 is driven into the switch mounting board 58 with the clip or outer end portion 86 in a horizontal plane. Rubber grommets 90 are received in the clip portions, and the dry reed switch 76 is mounted in the grommets in vertical position.

Each of the recesses 50 in the facing board 42 is provided with a downstop in the form of a rubber and felt pad 91 (FIGS. 2 and 5), and with the pedal 38 in lowered position the top of pedal extension 52 will be aligned with the approximate bottom of the corresponding reed switch 76. There is a rubber and felt upstop 93 at the top of each recess 50. With the pedals in normally raised position to which they are spring urged the tops of the pedals will be substantially aligned with the upper end of the respective reed switches 76.

On the end of each pedal extension 52 there is provided a flat, plate-like permanent magnet 92, held to the corresponding pedal extension by a non-magnetic screw 94. The magnets are polarized in their short dimension, having one pole on the left face and the other pole at the right face as viewed in FIG. 5.

When the pedals are in their normal raised positions, each magnet is opposite the overlapping reed tips and induces like poles therein. The tips thus repel one another and the switches remain open. However, when any pedal is lowered to its lowermost position with the corresponding magnet disposed "below the overlapping ends of the reeds 80, the magnetic circuit loses its symmetry and the reeds are magnetically moved into engagement, thereby completing a circuit through the switch. The switches are individually wired through cables 96 with plugs 98 or other suitable separable connectors.

The pedal board or clavier 36 is well adapted to unit or component construction. The dry reed switches 76 are all pre-assembled with the switch mounting board 58, and the pedals are all piovtally mounted on the base or support 40 and interfitted with the facing board 42. All that remains is to screw the switch mounting board onto the blocks 54 and bracket 66. Vertical adjustment of the switch mounting board relative to the remaining structure to insure operation of the switches at the proper time is readily effected by means of the screw-in slot mounting. Once the entire assembly has been put together, it simply is hooked onto the remainder of the organ casing, and the plugs 98 are inserted in appropriate corresponding receptacles.

Specific switches have been noted as being satisfactory for present invention. Further by way of illustration, it is desired that these switches should pull in at between thirty-four and sixty-four ampere turns and drop out between fifteen and thirty-five ampere turns, although other limits may be used. In actual practice, the magnets are one inch high and .750 inch wide, and .177 inch thick. Specific magnets that have been found satisfactory are made by Indiana Steel Products and identified as Indox 1, standard latch magnet, part number'FC41A700A, or stackpole Carbon Company as Ceramagnet A Code 61-578-1.

Since there is no physical connection between the pedals and the switch contacts it is apparent that no damage can be done to the contacts no matter how hard or with what violence the pedals might be depressed. Furthermore, since the switch contacts are sealed from the atmosphere, preferably in an inert gas, corrosion problems are substantially non-existent, and problems of dust settling on the contacts to cause erratic operation are completely eliminated.

Although specific reference has been made throughout to pedals, it will be apparent that the invention is also applicable to switching with the keys of the manuals. For generic purposes the word key will be used in the claims to cover either finger operated keys or digitals, or foot operated keys or pedals.

The specific example of the invention as herein shown and described is for illustrative purposes. Various changes in structure such as may occur to those skilled in the art will be understood as forming a part of the present invention insofar as they fall within the spirit and scope of the appended claims.

The invention is claimed as follows:

1. A key switch arrangement for electronic musical instruments comprising a plurality of elongated keys having inner ends and mounted for movement transversely of their longitudinal dimensions between a first rest position and a second operated position, a plurality of magnets respectively carried by said keys on said inner ends for respective movement therewith transversely of said keys, and a bank of switches disposed adjacent one another respectively adjacent said magnets, said switches being respectively disposed beyond said inner key ends and respectively being aligned with said keys longitudinally thereof in at least one of said positions, each of said switches having a pair of mutually engageable contacts at least one of which is magnetically movable, said contacts with said keys in rest position and said magnets respectively in a given relation to said switches being in a predetermined condition of engagement and non-engagement, selective movement of said keys selectively moving said magnets relative to said respective switches and reversing said predetermined condition of engagement and non-engagement.

2. A key switch arrangement as set forth in claim 1 wherein each of said magnets comprises a plate-like permanent magnet having a thickness and permanently magnetized in the direction of said thickess, said switches being spaced from said magnets in the direction of said thickness.

3. A key switch arrangement as set forth in claim 1 wherein each of said switches comprises a sealed, dry reed switch having two opposed, magnetically susceptible reed contacts with overlapping ends, each magnet being aligned with said overlapping ends with the respective key in rest position and magnetic symmetry holding said switches open.

4. A key switch arrangement as set forth in claim 1 wherein each switch comprises an encapsulated dry reed switch and is mounted by a pair of forks mounted on said base and a pair of grommets respectively received in said forks and gripping said switch.

5. A pedal key switch arrangement in an electronic organ of the type having a case and a pedal board with a pivot base space from said case, a plurality of pedals pivoted from said pivot base and having vertically movable ends disposed within said case, a plurality of magnets respectively on the ends of said pedals, each of said magnets being in the form of a fiat plate having a thickness disposed longitudinally of the respective pedal, said magnets being polarized in the direction of said thickness, and a like plurality of switches disposed adjacent one another and respectively spaced from the ends of said pedals and adjacent said magnets, each of said switches being normally open and magnetically closable, there being upstop rest and downstop operated positions for each of said pedals, the respective magnet effecting closing of a corresponding switch upon depression of a pedal from its upstop to its downstop position.

6. A switch arrangement as set forth in claim 5 wherein each of said switches is elongated and at least the movable switch contact is elongated in the same direction,

the direction of elongation being the direction of move- References Cited 9 UNITED STATES PATENTS 7. A switch arrangement as set forth in claim 6 wherein each switch comprises a pair of reed switch contacts 3,129,302 4/1954 Postel elongated in the stated direction and having overlapping 5 3,249,715 5/1966 Wanna" 335 206 ends, each magnet being aligned with the corresponding 3,255,326 6/1966 Schwartz et a1 200-865 overlapping ends with the respective pedal in upstop rest O G PATENTS positron, magnetic symmetry holding said switch contacts 390,213 4/1933 Great Britain.

open, each magnet moving from alignment upon movement of the respective pedal to downstop operated posi- 10 ARTHUR GAUSS Primary Examiner tion and magnetic asymmetry causing said contact ends magnetically to pull into engagement. B. P. DAVIS, Assistant Exammer.

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