Dyle, Charles A. (Chicago, IL)
Edwards, John W. (Lake Zurich, IL)

05/461662

10/14/1975

04/17/1974

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Hammond Corporation (Chicago, IL)

84/423R

200/5A, 984/345, 200/250, 84/DIG.007, 84/425, 341/22, 200/1R

G10H1/34; G10C3/12

84/1.01,1.17,439,440,DIG.7,DIG.22,423,425,427,433 200/1R,1A,5R,5A,159R,159B,250,DIG.1 340/365R,365A

3591749	PRINTED CIRCUIT KEYBOARD	July 1971	Comstock
3600528	MULTIPLE SWITCH CONSTRUCTION	August 1971	Leposavic
3624583	PLAYING DEVICES FOR ELECTRONIC MUSICAL INSTRUMENTS	November 1971	Nakada
3668337	MATRIX SWITCH WITH IMPROVED FLEXIBLE INSULATIVE SPACER ARRANGEMENT	June 1972	Sinclair
3668698	CAPACITIVE TRANSDUCER	June 1972	Demirdjioghlou et al.
3699294	KEYBOARD, DIGITAL CODING, SWITCH FOR DIGITAL LOGIC, AND LOW POWER DETECTOR SWITCHES	October 1972	Suddeth
3715443	WIRING SYSTEM BETWEEN SOUND SOURCE CIRCUITS AND KEYER CIRCUITS IN AN ELECTRONIC MUSICAL INSTRUMENT	February 1973	Ishimura
3732389	TOUCH ENTRY SWITCH ARRAY	May 1973	Kaelin et al.
3743797	STROKE CODED KEYBOARD SWITCH ASSEMBLY	July 1973	Hoffman
3757024	MUSICAL INSTRUMENT	September 1973	Stinson, Jr. et al.

Hartary, Joseph W.

Witkowski, Stanley J.

Bergstedt, Lowell C.

This is a continuation, of application Ser. No. 272,681 filed July 17, 1972, and now abandoned.

1. A miniature keyboard for an electronic musical instrument comprising:

2. Apparatus as claimed in claim 1, wherein said circuit board further comprises a plurality of mutually spaced conductive keying signal busses printed on the other side of said board with each of said busses being associate with a unique note of the musical scale, a first one of said contact fingers in each of said pairs being conductively connected through said board to an associated one of said keying signal busses such that a keying signal on said bus will be communicated to each of at least two contact pairs associated with octavely spaced musical tones, and a second one of said contact fingers in each of said pairs being adapted to be connected to keying circuitry for said associated tone.

BACKGROUND OF THE INVENTION

In U.S. Pat. No. 3,358,070 to Alan C. Young dated Dec. 12, 1967, and U.S. Pat. No. 3,358,091 to Charles Dyle dated Dec. 12, 1967, there is shown an arpeggio device upon which the present invention is intended to improve. A keyboard is formed of uniform, aligned, small rounded keys spanning all notes of three octaves, such that a thumb or finger may be run over the keyboard smoothly, and all the keys will be consecutively depressed and released. Each set of octavely related keys is connected to a separate bus which is connected in series to the like octavely related notes of the principal lower keyboard of the instrument and each key is connected individually to a keyer for the tone generators. Thus, as a note or chord is sounded on the principal lower keyboard and a finger is run along the arpeggio keyboard, only those notes the same or octavely related to the notes played on the principal keyboard will be sounded, securing perfect consonance of the arpeggio with the note or chord.

The arpeggio keyboard described in the above patents incorporates as separate elements individual keys, switch contacts, biasing springs, etc., for each individual note of the arpeggio, amounting, in all, to about 300 parts with the attendant complexity of assembly.

SUMMARY OF THE INVENTION

The simplified arpeggio keyboard of the present invention effects a vast reduction in the number of basic parts to simplify assembly greatly and reduce the cost substantially.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view of a printed circuit board with terminal pins attached;

FIG. 2 is a plan view of the spacer;

FIG. 3 is a plan view of the contact strip;

FIG. 4 is a plan view of the pressure pad; and

FIG. 5 is a plan view of the cover strip, all of which, sandwiched together, form the keyboard of the present invention;

FIG. 6 is a transverse section through the assembled keyboard taken along the line 6--6 of FIGS. 1-5; and

FIG. 7 is a perspective view of the keyboard mounted in the front strip of an electronic organ, the front strip being in the front strip of an electronic organ, the front strip being broken away in part to show the method of mounting.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In a preferred embodiment the keyboard 10 consists of five laminations; a printed circuit board 12, a spacer 14, a contact strip 16, a pressure pad 18, and a cover 20.

The circuit board 12 consists of an epoxy-glass substrate 22 with both sides thereof having circuit elements printed thereon; an outer, switch side 24 and an inner, bus side 26. The circuits of both sides are shown in Fig. 1, their interrelation being best understood from sucn superposed presentation. The circuitry on the switch side 24 is shown in relatively thick, scaled lines and the circuitry on the bus side 26 in thin lines, not necessarily to scale. It will be appreciated that the actual busses may be of any suitable width. The switch side has printed 49 switches 28 thereon, thus providing four chromatic octaves and a top C, consisting of spaced pairs of conductive strips extending transversely across the board 12. As illustrated, the left strip 30 of each of these switches includes a bus connection 32 and the right strip 34 extends to a note pin receptacle 36 adjacent the lower edge 38 of the board.

The reverse or bus side 26 has 12 parallel busses 40 printed thereon, one for each of the tones of the chromatic scale, extending longitudinally of the board in space relation and sloping at the right hand end toward the lower edge 38 of the board where they terminate in bus pin receptacles 42.

The note pin receptacles 36 and bus pin receptacles 42 are perforations arranged in a line along the lower edge 38 of the board 12 surrounded by conductive material, the plating of the bus pin receptacles extending from the bus side through the perforations to the outer or switch side 24 of the board for convenience of pin connection as will be later described.

In the configuration illustrated, the uppermost bus is assigned to the note C, the lowermost to C♯, the next above to D, and so on up to the C bus. The left-most switch is assigned to the note C, and from that C, the switches are successively assigned to the next adjacent semitone through four octaves of the chromatic scale to C"". At each point of crossing of the left hand elements 30 of the C, C', C", C'", C"" switches and the C bus, the board is perforated as at 32 with the plating extended through the perforations to connect those switch elements to the C bus. Similarly, the left element of each of the C♯ switches is connected to the C♯ bus as at 32a, the D switches to the D bus as at 32b, etc.

The invention contemplates a grouping of terminal pins for convenience of assembly. In the illustrated embodiment, the terminal pins 46 are molded in a line in five blocks, four blocks 48 carrying 15 terminal pins and one block 50 carrying four pins. The pins 46 extend through the block a short distance above 52 for soldered connection to the circuit board and a greater distance below 54 for plug-in circuit connection. The blocks are placed against the bus side of the circuit board with the short ends 52 of the pins extending up through the pin receptacles 36 slightly above the switch side where they are soldered to the conductive surrounds.

The particular grouping of the pins on the blocks and on the board is highly specific to a particular engineered embodiment. Needless to say, the division of pins between blocks and the number of blocks is wholly arbitrary and can vary widely. In the specific embodiment, however, the right hand pin of the block 50 of four is connected to the C switch terminal, the other pins being engaged in dummy receptacles 58 where they play a purely supportive function. The remaining 60 bus and switch terminal receptacles are divided among the blocks 48 of 15 pins. The right hand switch elements 34 of the groups of fifteen progressively converge toward their center at their ends as at 60 to enable a separation 62 between the pin mounting blocks 48 and 50 for keyboard mounting purposes as will be later described.

The spacer 14 is a rectangular strip of paper board or the equivalent, .008 inches thick having a window 64 therein proportioned to expose all the switches 28. The width of the spacer is such that it aligns with the edge of the board remote from the pins 46 and falls just short of the pins on its other edge. The length is such as to expose only the switches. Thus, with the left hand end of the spacer 14 aligned with the left hand end of the board 12, the right hand end of the spacer ovelies the area of the buses 40. The spacer 14 has a pressure sensitive adhesive on each side thereof to stick the spacer to the circuit board 12 and the contact strip 16 to the other side of the spacer.

The contact stip 16 is a sheet of Mylar having a series of transversely extending rectangular conductive contacts 68 plated on the bottom surface thereof. The contacts are arranged such that each overlies one of the switches 28. The contact strip is, of course, mounted to the assembly with the contact strips down so as to confront the switches 28.

The circuit board 12, spacer 14 and the contact strip 16 have index holes 70 formed therein such that the three components may be assembled on appropriately located pins to establish an exact relation between the parts.

A pressure pad 18 conforming essentially to the window 64 of the spacer 14 is placed on top of the contact strip 16 and in registry with the window 64. The pressure pad is a flexible vinyl from 1/16th of an inch thick any may have a pressure sensitive adhesive on its bottom surface for adherence to the Mylar contact stip.

The cover 20 is a strip of Teflon, 31/2 mils. thick and dimensioned like the circuit board 12. The Teflon has a pressure sensitive adhesive on one side thereof by means of which it is secured to the pressure pad, the exposed areas of the contact strip 16, and the exposed areas of the circuit board 12. Teflon is the material of choice in this application by virtue of the ease with which a finger may slide over it. In a characteristic application of this keyboard, the busses will be each connected to like busses serially connected to the key switches of the left hand or lower keyboard of an electronic organ such that depressing any C key, for instance, of the lower keyboard has the effect of energizing or grounding the C bus 40 of the arpeggio keyboard. Thus, the bus side 30 of each of the arpeggio C switches 28 is energized. The note sides 34 of each of the switches 28 are connected individually to keyers controlling the output of individual tone generators to the output system of the organ. Thus, as a finger is run along the Teflon cover 20, all of the switches 28 will be closed by the progressive depression of the contacts of the contact strip in to bridging relation with the two switch elements of each of the successive switches. Since, however, only the C switches will be energized, only the C keyers will be operated and successive C's sounded. Likewise, if the chord CEG is played anywhere on the lower keyboard, the C, E, and G busses willl be energized and all of the C, E, and G note switches conditioned for keyer operation.

This functional incorporation of the arpeggio keyboard an electronic organ and its mode of operation is all fully set forth in the above mentioned U.S. Pat. No. 3,358,070 to Young, and as the invention here resides in the keyboard itself and not in its circuitry or mode of note sounding, illustration is believed irrelevant and unnecessary.

The keyboard of the present invention can be mounted in a variety of ways as shown in the above mentioned U.S. Pat. No. 3,358,070. A specific means of mounting has been devised, however, (Fig. 7) which provides good accessibility of the keyboard to a player's hands involved with the principal keyboards and lends itself well to the wanted design characteristics of the organ. The front strip 74 of the organ is that vertical panel between the upper, right hand keyboard and the lower, left hand keyboard. In the specific embodiment it is a metal channel with the base 76 exposed and decoratively finished and the flanges 78 thereof inwardly turned. A slot 80 is formed in the base 76 proportioned to accommodate generously the bulge in the Teflon cover 20 occasioned by the pressure pad 18. Clips 82 having a central portion 84 adapted to embrace the backside and the longitudinal edges of the keyboard engage the keyboard in the spaces 62 between the pin blocks 48 and 50. The ends of the clips are backwardly bent as at 86 to approach closely and parallel the flanges 78 of the front strip 74 and have struck-out points 88 which engage the flanges 78.

From the foregoing description it will be appreciated that a keyboard has been devised here which offers enormous advantage in terms of cost of components and cost of assembly over that shown in the above mentioned patents to Young and Dyle.

Some dimensions are of interest in that the keyboard should be short to minimize the sweep of the finger necessary to operate it and yet it should be possible to sound a single note without closing adjacent switches. The spacing of the elements 30 and 34 of each switch 28 is .031 inches and the switch elements are .031 inches wide, so the width of each switch is .093 inches. The spacing of the switches center-to-center is .172 inches. The contact members of the contact strip are also .093 inches wide, and, of course, equally spaced with the switches. The circuitry is, conventioanlly, gold on nickel on copper. The overall length of the keyboard proper as represented by the pressure pad 18 is about 9 inches.

The dimensions given herein are, of course, illustrative and not critical, but in order to obtain a clean arpeggio effect, it is desirable that one note of the arpeggio release before the next note is sounded. Arpeggios and chords conventioanlly used seldom incorporate semitone intervals. The spacing of the switches, taken together with the recited thicknesses and materials which go to make up the combined keyboard sandwich, result in an assembly sufficiently locally responsive such that the pressure of a tip of a finger will make positive closure of the switch directly under the fingertip with a slight effort, but at the same time not close adjacent switches. In other words, the pressure of a finger might close two adjacent switches if it were centered over the space between, but if it were centered directly over one switch, the adjacent switches would not be closed. It the area of pressure contact were broadened, of course, as with the ball of the thumb, as many as five or six adjacent switches would be closed which might be desired in some arpeggio effects.

It must again be emphasized that the above described embodiment of this invention is a highly specific commercial model, and many variations may be readily imagined without departing from the basic concept thereof. It is, therefore, desired that this invention be regarded as being limited only as set forth in the following claims.