US3068334A - Keyboard for electrical instrument - Google Patents

Description

Dec. 11, 1962 'r. B. GIBBS ETAL 3,068,334

KEYBOARD FOR ELECTRICAL INSTRUMENT Filed July 24, 1959 4 Sheets-Sheet 1 T. B. GIBBS ETAL KEYBOARD FOR ELECTRICAL INSTRUMENT Dec. 11, 1962 4 Sheets-Sheet 2 Filed July 24, 1959 Dec. 11, 1962 T. B. GIBBS ETAL KEYBOARD FOR ELECTRICAL INSTRUMENT 4 Sheets-Sheet 3 Filed July 24, 1959 Dec. 11, 1962 'r. B. GIBBS ETAL 3,063,334

KEYBOARD FOR ELECTRICAL INSTRUMENT Filed July 24, 1959 4 Sheets-Shet 4 United States Patent i 3,068,334 KEYBOARD FOR ELECTRICAL INSTRUMENT Thomas B. Gibbs and Joseph G. Polasik, Delavan, Wis.,

assignors to Gibbs Manufacturing & Research Corporation, a corporation of Wisconsin Filed July 24, 1959, Ser. No. 829,285 1 Claim. (Cl. 200-166) This invention relates to an electrical musical instrument and more particularly to a keyboard and switching arrangement for such an instrument.

In an electrical musical instrument, as an electric organ, manually operable keys actuate switches which complete circuits that generate or select the desired tones. Particularly in an organ, provision is made for the production of a plurality of tones of differing quality for each note or frequency and corresponding with the different voices or stops with which the organ is provided. The mechanical layout of key switching systems for such instruments is necessarily rather complex and in many cases difiicult and expensive to assemble and service.

A principal object of this invention is the provision of a new and improved key switch, stop selector and key mounting mechanism.

One feature of the invention is a switching arrange: ment including a first switch member, a second switch member movable into contact with the first completed circuit and means movable relative to both the switch members between blocking and non-blocking positions with respect to the second switch member. Another feature is that one of the switch members comprises an elongated bus having a plurality of selectively actuable switch members mounted in spaced relation along the length thereof and individually movable into contact therewith to complete electrical circuits and an elongated rod is provided adjacent the bus rotatable between blocking and non-blocking positions with respect to the actuable switch members. A further feature is that the bus is mounted between end members of a frame and the blocking rod is of an electrical insulating material, journalled in the end members for rotatable movement between blocking and non-blocking positions with respect to the selectively actuable switch members.

Still another feature is that the individually operable switch members forming the second switch means are mounted on a carrier removably secured to the base on which the elongated bus is mounted. This permits removal of the entire movable switch assembly and its associated circuitry and calling for ease in repair or replacement.

Yet a further feature of the invention is that the switch means include a plurality of elongated bus elements, a plurality of selectively actuable switch members mounted in spaced relation along the length of the bus elements, each member including a plurality of switch elements one associated with each of the buses, elongated rods adjacent each of the buses rotatable between blocking and nonblocking position with respect to the switch elements and means for selectively rotating the rods.

And another feature is that the rod rotating mechanism includes a stop tablet, a pivotal mounting for the stop tablet, an adjustable motion limiting stop surface and an over-centered spring urging the tablet toward a limiting position. A further feature is the provision of such a mechanism in a musical instrument having upper and lower manuals with all of the stop tablets mounted above the upper manual, crank and linkage means connecting a portion of the operating members with the stop determining mechanism of the upper manual and crank and flexible motion transmitting means connecting an- 3,068,334 Patented Dec. 11, 1962 other portion of the operating members with the stop determing mechanism of the lower manual.

Still another feature is the provision of an elongated key element having a knife edge pivot supporting it at a point intermediate its end surfaces. And a further feature is the provision of adjustable spring means urging each key toward one of two limiting positions, and comprising an adjustable backer for each of the springs.

Further features and advantages of the invention will readily be apparent from the following specification and from the drawings, in which:

FIGURE 1 is a fragmentary plan view of an instrument keyboard, switch mechanism and stop selectors embodying the invention;

FIGURE 2 is a vertical sectional view thereof;

FIGURE 3 is a view similar to FIGURE 2 illustrating certain modifications;

FIGURE 4 is an enlarged and partially exploded perspective view of the key switch and stop mechanism;

FIGURE 5 is an enlarged section illustrating a single switch member in elevation; and

FIGURE 6 is a fragmentary section taken along line 6-6 of FIGURE 2 illustrating the key backing springs.

The mechanism disclosed herein is designed for use in an electronic organ of the type disclosed and claimed in copending Ziehlke application Serial No. 753,771, now abandoned, filed August 5, 1958, and assigned to the assignee of this invention, and insofar as details of the key switching and stop mechanism are affected by the tone generating system of the instrument will be so described. The novel features of the present invention may find use in electronic organs, pianos and like instruments utilizing other tone generating systems.

Turning now to the drawings and more particularly to FIGURES 1-3, a portion of an organ keyboard, stop selector and the associated switching mechanism are shown. The keyboard has an upper manual 15 and lower manual 16 each including a plurality of keys arranged in the usual manner. A base or supporting structure 17 and 18 is provided for the upper and lower manuals, respectively, and the key-s and associated switching mechanisms are mounted thereon. Stop selector mechanism 19 is mounted on a portion 20 of the instrument cabinet carried between side members 21 of the upper manual support. A cover 22 may be swung back or removed to provide access to the interior of the instrument. Side portions 21 of the upper manual support have hook portions 21a pivotally supported on bearings 23 carried by the side walls 24 of the cabinet, and may be swung up exposing the lower manual.

The tone generating mechanism of the instrument is not illustrated in the drawings but is preferably of the type illustrated in the Ziehlke application. This preferred tone generating system includes a mask plate having light transmissive portions corresponding with a function of desired musical tones. A scanning disc rotates past the mask openings and the light passed by the scanning disc is converted to an electrical signal by a photocell. The speed of the scanning disc determines the frequency of the signal and the mask patterns the tone character. The desired mask areas are illuminated by individual light bulbs and the switches illustrated in the present application are connected in the bulb circuits, preferably between the bulbs and a reference potential as ground. Further details of the tone generators may be found in the Ziehlke application.

The switch mechanisms for each of the manuals each have a plurality of fixed bus connectors 26 supported by a framework including frame end members 27 and intermediate members 27a. The bus frame members are in turned carried by a plate 28 secured to the keyboard base members 17 and 18. The movable switch means include a plurality of individually actuable switch members 29 mounted on a carrier 39 secured to base members 17 and 18. As best seen in FIGURES 4 and 5 each of the switch members 29 includes a plurality of switch elements or wires 31 mounted in a support 32 of insulating material, carried in a vertical slot in plate 30. A spacer 33, also of insulating material, is mounted on the wire switch elements 31 holding them in alignment and serving as an actuating member for the switch. The wires or switch elements 31 extend through spacer 33 and project between bus wires 26, each switch element being below the bus wire with which it is associated. The lower portion of spacer 33 is provided with a collar 34 which rests on the upper surface of bus frame support plate 28 while the lower end of the spacer member extends through a slot 28a formed therein. The inner end 35 of a key 35 is positioned under spacer 33 and when the key is depressed, spacer 33 is lifted moving switch elements 31 upwardly and into contact with certain of the bus elements 26, as will appear.

A control rod 33, of insulating material, is associated with each of the bus wires 26 and is rotatably mounted in the frame members 27 and 27a. A series of notches or cut-out portions 39 are provided along the length of the rods 38, aligned with the elements 31 of the movable switch means 29. When the rod 38 is in a position with the notch 39 facing downwardly, the lowest surface of the rod aligned with switch element 31 is above the bottom of the associated bus 26, and switch element 31 may contact the bus when member 33 is lifted by a key. Rotation of rod 38 through 99 moves notch 39 to the side and blocks the associated switch element 31 from contacting bus 26. The upper surface in each of the rods 38 extends above the top of the associated bus 26 preventing the end of the next wire 31 above the bus from accidentally contacting it if the wire switch element should be bent.

The individual switch elements 31 ordinarily will be connected to individual circuits, and these circuits will be connected to appropriate bus wires 26, or not, when a particular playing key is depressed, depending upon the positions of the blocking rods 38.

The stop selector mechanism includes a plurality of stop tablets or tabs 42 pivotally mounted on brackets 43 on the inner surface of cabinet portion 29 and which project outwardly above upper manual 15. The bracket 43 to which tablet 42 is hinged has an arm 44 extending downwardly therefrom with a vertical slot 45 formed in the end thereof. A pin 46 attached to a downwardly extending member 48 secured to the rearward extension 43' of the tab 42 extends through slot 45 and is provided at its ends with cushions 47 and 47a. Cushion 47a on the inner end of pin 46 is adjustable, limiting the position of tablet 42 when it is depressed. The lower portion of the extension 48 has connected therewith an overcentered spring arrangement 49 which is returned to a fixed bracket 50. Spring 49 urges tablet 42 toward either of its limiting positions determined by cushion stops 47 and 47a. An arm 51 secured to rearward extension 43 extends inwardly over the top of the switch mechanism and is connected through link 52 and crank 53 with one of the rotatable rods 38. With the tablet in its raised or brokenline position (FIGURE 3) arm 51 is depressed and insulating rod 38 rotated fully in a clockwise direction to the inoperative or off position for that particular stop or voice of the instrument. When tablet 42 is depressed, arm 51 raises to the solid position of FIGURE 3 rotating rod 33 in a counterclockwise direction and positioning slots 39 to open downwardly permitting switch elements 31 to contact the associated bus 62. The eifective length of link 52 may be adjusted by nuts 52a establishing the off position of rod 38 with the tablet raised. Cushion 4% may be adjusted along the length of pin 46 to establish the position of the rod in the on position with tablet 42 depressed. The mechanism of FIGURES 3 and 4 is duplicated for each of the stops in the upper manual 15.

The tablets 42 for the lower manual are mounted with the tablets for the upper manual along the top of cabinet portion 20 and the mechanical stops and over-centered spring arrangement are identical. However, as best seen in FIGURE 2, the mechanical connection between the tablet and the rotating insulating rod is somewhat different. Arm 55 extends downwardly from tab extension 43' and is connected with the center wire 56 of a flexible drive cable 57. The outer cable sheath 58 is clamped at its ends 59 while wire 56 is connected with a crank 60 mounted at the end of the insulating rod. The operation is the same as the upper manual, i.e. with the tablet in the raised position the insulating rod is turned in clockwise direction to the oif position while when the tablet is depressed the insulating rod turns in a counterclockwise direction to the operative position. A separate tablet 42 and connector cable 57 are provided for each of the stops or voices in the lower manual.

Each of the individual switch elements 31 in both manuals have insulated conductors 64 connected with the fixed ends, which project rearwardly through mounting blocks 32. These conductors are in turn gathered into the cable 6%. The cable 65 can lead to any position where it is convenient to connect the individual wires to the circuits it is desired to switch by means of the mechanism just described. The sole connection between the movable switch assembly 29 and the remainder of the mechanism is in the mounting of support plates 30 on the manual base plates 17 and 18. Removal of screws 66 permits the entire movable switch assembly to be lifted out along with cabled conductors 65. It will be noted that the lower ends of switch actuating members 33 are received in slot-like openings 28a of the bus framework support 23 and may readily he slipped out during removal. Thus, if repair or replacement of all or any portion of the switch assembly is necessary mechanism 29 may easily be removed from the instrument and the work performed in a more convenient location. Also removal of switch assembly 29 exposes all of the bus con ductors 26v and their associated blocking element 38 for repair, replacement or adjustment.

Referring again particularly to FIGURES 2 and 3, the mounting arrangement for the keys is shown. In FIG- URE 2 a key 70 has secured to its undersurface a channel member 71 provided with an extension 72, the end portion of which provides the switch actuating element 35. An indented bearing surface 73 is formed in extension 72 and rests on a knife edge pivot 74 extending upwardly from base plate 17 or 13. A stop member 75 is carried by the undersurface of the key, adjacent the outer end thereof and moves between a pair of cushion pads 76. A third cushion 77 is carried by a support 78 between the depending sidewalls 70a of the key and limits sideways movement of the key.

An adjustable key pressure spring arrangement is provided adjacent and inwardly of the pivot point of the key. As shown in the drawings, a bar 80 is mounted on upright studs 81 at either end of the keyboard with the individual springs 82 extending between the bar and the upper surface of extension portion 72 of each key. The springs are preferably retained in position between the bar and the key by seating around raised collars 72a and 80a formed in the two members. The key pressure may be adjusted by raising or lowering bar 80 through the manipulation of nuts 81a threaded on studs 81.

A modified key mounting arrangement is shown in FIGURE 3 where the key extension 72 is provided with an upstanding mounting plate 85 which mates in face-toface relation with an upstanding resilient support 86 secured to the base member. A spring clip 87 secures the mounting plate 85 with support 86 and the plate support 86 may be keyed together by suitable means, as an extension on one of the parts which projects into an opening on the other part preventing relative sliding movement between them.

While we have shown and described certain embodiments of our invention, it is to be understood that it is capable of many modifications. Changes therefore, in the construction and arrangement may be made without departing from the spirit and scope of the invention as disclosed in the appended claim.

We claim:

An electrical switching arrangement comprising: first switch contact means comprising a group of parallel bus elements in spaced relation, each of said bus elements adapted to form a portion of an individual circuit, a plurality of side-by-side gangs of second switch contact means, each of said gangs comprising a plurality of parallel switch blades fixed at one of their ends with their free ends positioned individually adjacent but out of contact with individual ones of said bus elements, a plurality of gang actuating means adapted individually for flexing all of the blades in a particular gang simultaneously to tend to move the free ends of all of the blades in the particular gang individually against individual ones of said bus elements, a plurality of rodlike members extending generally parallel to said bus elements, said rod members extending through said gangs and positioned individually adjacent an individual blade-free end in each of said gangs to intercept said blades to prevent said free ends from contacting said bus elements when said free ends 6 are flexed by said actuating means, each of said rod elements having a plurality of longitudinally spaced axially aligned recessed blade clearance portions which are aligned with the blades of the different switch groups with which said element is associated to provide clearance to permit said last designated blades to move into engagement with their bus element, and means for moving said rod elements individually to shift said clearance portions into and out of alignment with their respective blades.

References Cited in the file of this patent UNITED STATES PATENTS 1,269,617 Ledwinka June 18, 1918 1,361,006 Brown Dec. 7, 1920 1,462,251 Slough July :17, 1923 1,775,260 Verlinden Sept. 9, 1930 1,851,459 Smith Mar. 29, 1932 2,069,518 Chittick et a1 Feb. 2, 1937 2,261,999 Hess Nov. 11, 1941 2,285,890 Blosser June 9, 1942 2,401,113 Schroeder May 28, 1946 2,567,870 Bozak et al Sept. 11, 1951 2,614,195 Kitto Oct. 14, 1952 2,700,914 Barnett Feb. 1, 1955 2,844,065 Corwin July 22, 1958 2,846,916 Osborne et a1. Aug. 12, 1958 2,960,580 Aquillon Nov. 15, 1960 FOREIGN PATENTS 634,123 France Nov. 8, 1927

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