US2246371A - Piano keyboard for accordions - Google Patents

Description

June 17, 1941. c UNDEBERG 2,246,371

PIANO KEYBOARD FOR ACCORDIONS Filed April 11, 1940 Z 7 Z2 Z6 INVENTOR.

A ORNEY5.

Patented June 17, 1941.

PIANO KEYBOARD FOR ACCORDIONS Carl Lindeberg, De Kalb, 111., assignor to The Rudolph Wurlitzer Company, Cincinnati, Ohio,

a corporation Application April 11, 1949, Serial No. 329,097

6 Claims.

This invention relates to a piano keyboard for accordions, particularly the construction of the keys and their connection with the valve actuating key fingers, as well as the key bed and mounting therefor.

The conventional structure of key action for accordions involves the use of an aluminum wire which is first driven into the key and then bent down so the valve fastened to its operating end will properly seat. However, in this construction, whenever the key level was changed, such as the height of the front end of the key, the aluminum wire had to be bent. This is a most tedious process, requiring highly skilled mechanics who could bend the aluminum wire properly, and wherein it is bent a little too much, the front key level is thrown out of alignment.

The object of this invention is to provide an action which permits a more positive and permanent air tight seating of the valve, as well as a quick, easy and inexpensive way of regulating the height of the keys and leveling all of the keys without in any Way afiecting the key finger and valve. This is accomplished by providing a rigid extension of the key finger, which is adjustable with respect to the key through a lever action controlled by a spring and regulating screw. By merely turning the regulating screw, the height of the front end of the key may be changed, whereas the key finger and valve remain in the same position at all times.

A further feature of the invention resides in the arrangement of the key finger extension where it is adjustably joined with the key so that it acts in conjunction with the guide rail to guide the key movement in place of the usual guide pins. It may be mentioned that the front guide pins of the conventional construction would at times be bent out of their proper position as the player may roughly play glissando passages. This would result in the guide pins becoming loose, and in some instances actually falling out of place, wherein the key fingers and their extensions, which form a rocker arm as herein provided, are made of steel, the key may be more perfectly and permanently guided in its action and maintained in proper alignment. Furthermore, such an arrangement is substantially less expensive to produce and maintain than the conventional use of front guide pins.

Another feature of the invention resides in the arrangement of the key fingers so that they may be individually removable, as more specifically set forth and described in the following specification.

Still another feature of the invention resides in the arrangement of the spring for normally maintaining the valve in closed position and the key in lowered position, particularly constructed and arranged to render the action more quiet and to entirely eliminate vibration of the action.

The full nature of the invention will be understood from the accompanying drawing and the following description and claims:

Fig. 1 is a cross sectional view through a portion of the treble box of the accordion and key bed showing a key with its key finger in normal adjusted position. Fig. 2 is a plan view of one end of the treble box and valve board with the key bed extending therefrom showing the position and arrangement of one of the keys in respect to its key finger. Fig. 3 is the same as Fig. 1 showing the key adjusted with respect to its key finger in lowered position. Fig. 4 is the same as Fig. 3 showing it in raised position. Fig. 5 is a top plan view of the key. Fig. 6 is a side elevation of the key with the rear end shown in section. Fig. 7 is a bottom plan view of the key. Fig. 8 is a section taken on the line 8-8 of Fig. 5. Fig. 9 is a side elevation of the key finger with its rocker arm extension.

In the drawing there is shown the treble box if) of an accordion having a valve board ll provided with a series of natural valve ports l2 and sharp valve ports i3 adapted to be controlled by the usual valve l4. Secured to the treble box and extending at an angle therefrom in the usual manner there is provided a pair of key bed supporting arms !5 at each end thereof between which a key bed guide rail It extends. Said key bed is provided with the usual felt stop strip ll.

For operating the valves there is provided a key finger l8 having one end secured to the valve l4 and the other end pivotally mounted upon a pivot rod 18. Adjacent to and inwardly of its pivotal mounting, said key finger is formed with a key finger extension 2!) which may be integral therewith or welded thereto as a separate piece, and which forms with said key finger a rocker arm. Said key finger is preferably formed of a thin sheet metal stamping having substantial width to provide rigidity in its operation while permitting it to be bent to conform to the relative positions of the operating key and valve.

The key 25 is herein illustrated as of the usual wood block construction having an overlying finish indicated at 22, such as ivory or Celluloid. However, such key may be made to advantage of metal or similar material, as may be desirable.

Toward the rear end of the key it is vertically slotted longitudinally and centrally thereof, as indicated at 23, to receive the key finger extension 23 therein. Said key finger extension and key are pivotally connected by a pivot pin 24 extending through an opening 25 formed in the key. Thus, the key may be adjusted as to its alignment with the rigid metal key finger extension 20 about said pivotal connection. For this purpose there is sufficient space provided between the key and extension to allow for the necessary relative movement.

The key is provided on its underside with a recess 26 to receive a stiff compression spring 21, said compression spring being mountable in a recess 28 of the finger key extension 20. Thus, the forward end of the key is forced upwardly or away from the extension by the tension of said spring about the pivot 24, as shown in Fig. 4.

On the other side of the pivotal mounting, the key is provided with an internally threaded sleeve 29 extending vertically therein to receive a threaded regulating screw 30. The finger key extension 26 is provided with a recess 3| for clearing the sleeve 29. The end of the regulating screw is positioned to engage said extension at the bottom edge of its recess.

By screwing downwardly on the regulating screw, the rear end of the key is forced away from the extension so as to drop the front end thereof downwardly; compressing the spring 21, as shown in Fig. 3. As the screw is released, the spring 21 will force the forward end of the key upwardly, as shown in Fig. 4. The balance adjustment of the key through the medium of the regulating screw 30 is shown in Fig. 1.

In lieu of theusual front guide pins for maintaining the keys in alignment upon the key bed, the finger key extension 20 is provided at its forward end with a downwardly turned portion 32 extending into a slot 33 provided in the rear edge of the key bed guide rail 16. Said guide rail is provided with a plurality of rearwardly extending parallel slots, one for each key. Thus, the finger key extensions 20 are maintained in proper alignment and operating position through engagement with the slots in the key bed guide rail which in turn maintain the keys in their proper operating position in the same manner as the conventional guide pins.

The key finger is normally maintained in valve closing, position by the spring 34' having one end anchored to the guide rail It at 35 and the other end anchored to an overhanging portion of the keyfinger at 36. The rear end of the key finger proper, extending beyond its junction with the extension 20 is provided with a bayonet slot 3! which interlocks with the pivot rod l9. Said pivot rod extends through the pivot rail 38 of the treble box. The pivot rail is provided with a plurality of slots 39 for receiving and spacing the finger keys to maintain them in operating alignment. By this arrangement, the individual keys and their associated finger keys may be conveniently removed from the key bed by disconnecting the spring 34 and lifting the finger upwardly about one-eighth of an inch. This permits it to become disengaged from the pivot rod by a forward movement due to the bayonet slot arrangement. Thus, the individual keys may be conveniently and quickly installed or removed.

The invention claimed is:

1 In a piano action for accordions, the combination with a valve board and a key bed, of a key finger having a valve on one end thereof, said key finger having a rigid portion extending over said key bed, a key, and adjusting means connecting thefinger and the key whereby the latter may be adjusted relative to the former.

2. In a piano action for accordions, the combination with a valve board and a key bed, of a key finger having a valve on one end thereof, and a pivotal connection with the accordion at the other end, an extension rigidly formed therewith and extending at an angle thereto substantially in alignment with said key bed, a key pivoted intermediate its ends on said extension and overlying said key bed, and a regulating screw for adjusting the relative position between said key and extension.

3. In a piano action for accordions, the combination with a valve board and a key bed, of a key finger having a valve'on one end thereof, said key finger having a portion extending over said key bed, a key having a bifurcated portion thereof embracing said key finger extension, a pivot pin for pivotally connecting the bifurcated portion of the key and extension, and a regulating screw extending through the bifurcated portion of the key into engagement with the extended portion of the key finger for adjusting their relative position.

4. In a piano action for accordions, the combination with a valve board and a key bed, of a key finger having a valve on one end thereof, said key finger having a portion thereof extending at an angle to the valve portion and in the plane of said key bed, a key lying over said key bed having the rear end thereof bifurcated to embrace the extended portion of the key finger, means for pivotally securing said key to said portion, a spring interposed between said key and key finger portion for normally forcing them from' each other about said pivotal connection, and a regulating screw on the other side of said pivotal connection from said spring for adjustably compressing said spring for adjusting the relative position of said key and key finger.

5. In a piano action for accordions, the combination with a valve board and a key bed extending at an angle thereto, of a pivot rail between said valve board and key bed provided with a plurality of slots, a rocker arm pivotally mounted to said pivot rail within one of said slots and guided thereby, said rocker arm comprising a key finger having a valve carrying portion overlying the valve board and a key carrying portion extending in alignment with said key bed, means for adjustably securing a piano key to said key carrying portion of the rocker arm, the pivotal portion of said rocker arm lying within the guide slots of said pivot rail-being provided with a bayonet slot, and a pivot rod extending through said guide rail for pivotally mounting said rocker arm through its engagement with said bayonet slot.

6. In a piano action for accordions, the combination with a valve board and a key bed, of a guide rail, said guide rail being provided along its inner edge with a plurality of vertical parallel slots, one for each key, a key finger pivotalIy mounted between said valve board and key bed, a valve on one end of said key finger adapted for closing engagement with said valve board, a key supporting extension on said key finger extending over said key bed, a key, means for adjustably mounting said key on said extended portion, and a guiding portion on the end of said extended portion extending into and slidably movable within one of said slots in said guide rail for guiding the action of said key.

CARL LINDEBERG.

Images