US2277077A - Piano action - Google Patents

Description

Patented Mar. 24, 1942 PIANO ACTION Charles H. Dasenbrook, Rockford, Ill., assignor to Thayer Action Company, Rockford, 111., a corporation of Illinois Application March 9, 1940, Serial No. 323,080

11 Claims.

This invention relates to an action especially adapted for use in pianos having vertically disposed strings and more particularly to actions of the direct blow type in which the key acts directly on the wippen.

The primary object is toprovide an action of the above character having a novel construction and arrangement of the action parts by which a substantial reduction in over-all height is obtained as compared to the actions now in use.

Another object is to improve the speed of repetition in upright grand piano actions.

A more detailed object is to carry out the foregoing object through the use of action parts of more or less standardized construction.

Other objects and advantages of the invention will become apparent from the following detailed description taken in connection with the accompanying drawings, in which- Figure 1 is a fragmentary vertical cross-secticnal view through a piano key and action unit embodying the present invention, the parts being in normal released position.

Fig. 2 is a similar View with the parts in actuated and checked positions.

Fig. 3 is a fragmentary elevational view of the action frame illustrating a modified mounting of the damper rail.

While the invention is susceptible of various modifications and alternative constructions, I have shown in the drawings and will herein describe in detail the preferred embodiment. It is to be understood, however, that I do not intend to limit the invention by such disclosure but aim to cover all modifications and alternative constructions falling within the spirit and scope of the invention as expressed in the appended claims.

Referring now to Figs. 1 and 2 of the drawings, 3 indicates one of the piano keys receiving an upright guide pin 4 and fulcrumed in the usual way on a balance rail 5 supported by the key bed 6 which may include a member 6 or socalled key frame. The rear edge of the bed may be supported by a ledge 8 projecting forwardly from the vertical plate E8 on which the strings I!) are mounted. In released position, the rear end of the key rests on a pad 'o on the bed mem ber 6 The key may be undercut at its rear end and carries the usual screw 1.

The main operating parts of the action are mounted on a rigid frame including metal brack ets I! having feet 9 resting on the bed 6 immediately behind the keys and fastened to the bed by screws it. The brackets curve upwardly and rcarwardly and have a central portion l2 against the underside of which the top of the rail [3 is adapted to seat accurately being clamped thereto by screws l2 entered through wings 12 on the upstanding capstan portion [2. The rail is thus disposed with its transverse dimension generally horizontal instead of vertical as is the general practice. Hammers H are carried on the upper ends of shanks l5 having butts 22 at their lower ends pivotally mounted at l4 on bars l5 screwed to an undercut portion l3 at the rear edge of the rail. The

posed horizontally beneath the rail hammers ll are thus adapted to be projected against the strings H] by swinging of the shanks rearwardly. In released position shown in Fig. 1, each hammer shank rests against a cushion on a rail 20 mounted on the upper ends of arms 2| on the brackets I I.

A spring 22 anchored in a ledge 22 on the rail l3 and acting on butt 22 urges the hammer away from the string. Adjacent the shank IS, the butt 22 is covered with a pad 23 providing a curved knuckle surface 24 which faces forwardly and upwardly and is engaged eccentrically of the pivot I4 by the free end 25 of a jack 2,6. The latter projects generally horizontally but preferably downward slightly from a pivot 21 on a post 28 which is rigid with a whip 29 in the form of a substantially right angular bellcrank. This is supported near its center by a pivot 30 on a block 3| projecting from the forward edge of the rail 13. The post 28 projects rearwardly and horizontally from the upstanding arm 3| of the bellcrank which has a second arm 32 projecting horizontally and forwardly so as to overliethenear ends of the keys. The rounded head of capstan screw 1 bears directly on a pad 33 fastened to the underside of the arm 32 at the free end thereof.

A spring 34 acting in compression between the free end of the whip arm 3 I and a heel 35 on the jack maintains the free end 25 against a pad 36 on the butt in the released position of the parts. The heel 35 coacts with a regulating button 31 adjustably supported by an auxiliary rail 3'l mounted on fingers 38 screw-threaded into the main rail.

In the present instance, back checking of the hammer is effected by coaction between a leather covered block 39 and a convexly curved surface 40 on a catcher in the form of a heel 4| integral with the hammer head 42 and disposed on the side of the shank I6 opposite the hammer proper. The block 39 is fast on the end of an upright wire 43 anchored in the end of the whip arm 3F. The usual bridle wire 44 is also anchored in this end and supports one end of the bridle tape 45 the other end of which is attached at the junction of the shank l6 and butt 22.

The usual string damper 46 is carried by an upright rod 41 anchored in the free end of a lever 48 which, in the present instance, is disl3 and is pivoted intermediate its ends on a post 49 upstanding from a rail 56. In the form shown in Fig. 1, this rail is screwed to the rear edge of the key bed. A spring 50 urges the damper toward active position (Fig. l) and the damper is released in response to key actuation by a spoon 5| projecting horizontally from a depending arm 52. When the key is struck (Fig. 2), movement of the damper wire 41 is limited by a cushioned rail 53 which is supported by upwardly and rearwardly inclined arms 54 on the brackets H.

The dimensions indicated on Fig. 1 as a, b, c, and d are approximately 4%, g g, 1 and 1% inches respectively. The key lever ratio is about 1.54.

Starting with the parts in the released position shown in Fig. 1, depression of a key 3 rocks the whip arm 3W rearwardly and the key motion is imparted to the knuckle 24 through the jack, the hammer being thereby thrown toward the string. In the movement of the parts following engagement of the heel 35 and the regulating button 31, the free whip end 25 is raised progressively and rides up the knuckle surface, becoming ineffectual about the time that the hammer strikes the string. In the final portion of these movements, the spoon 5| depresses the rear end of the lever 48 releasing the damper as shown in Fig. 2. During the advance of the whip to actuate the jack, the back check follows the hammer rearwardly and becomes positioned as shown in Fig. 2 in the fully advanced position of the parts. It is thus positioned to catch the heel 4| as the hammer rebounds.

As the key pressure is released, the back check and hammer move forwardly under the action of the springs and the weights of the parts including the bellcrank arm 32 which is made relatively thick as shown in order to assist in the recovery. This permits the jack end to move downwardly against the pad 35 and thus engage the butt surface in proper position for the next blow.

It will be observed that except for the shape of the whip and the changed position of the butt surface 24 relative to the hammer shank, all of the main parts of the improved action, including the hammers, the jacks, and the rail l2, are of the sizes and shapes which have become more or less standard with action manufacturers. The connections between these parts are located in the same relative positions and the parts function in the same way as those of standard actions, thereby insuring reliability of operation, sensitivity of touch, and rapidity of recovery in response to key action. At the same time, a substantial reduction in the over-all height of the action has been obtained. This is due in part to location of the jack in a substantial horizontal position thereby eliminating a substantial portion of the height attributable to the upright jacks heretofore generally used. A further reduction in height is attained by inclining the main rail and the jack downwardly and rearwardly, the knuckle surface being shaped and positioned relative to the hammer to permit proper functioning of the jack in this position. As a result, the hammer pivot I4 is actually disposed below the front of the key and the )distance between the striking line and the key bed is about five and one-half inches which compares to seven and one-half inches for the most compact direct blow action heretofore used commercially.

This reduction in over-all height greatly facilitates styling of the piano case without in any way detracting from the performance of the action. The so-called touch is as light as that of ordinary actions and the recovery of the jack on release of the key is even more rapid. This is due to the fact that the jack, being disposed generally horizontally, may be increased in length as desired and the hammer may be made of substantially greater length than the hammers commonly used in so-called compressed actions while still retaining the desired increased vertical compactness. With a longer hammer, the arc of travel of the knuckle 24 in recovering relative to the jack is correspondingly decreased thereby contributing to the increased speed of repetition of the improved action.

The changed positions of the jack and rail have, of course, necessitated the use of a bellcrank type whip and relation of the back check, the catcher, and the damper actuating lever. In their changed positions, however, these parts do not add to the height of the action and their functioning is equally effectual.

By mounting the damper lever rail 55 directly on the keybed as shown in Figs. 1 and 2, the action proper constitutes a unit separate from the damping mechanism easily removable to render this mechanism accessible for adjustment relative to the strings. In some instances, however, it may be desirable to make the damping mechanism a part of the action proper and removable therewith from the piano case. To this end, the key bed may be shortened as shown in Fig. 3 and the rail 56 fastened as by screws 59 to arms 58 formed integral with the feet of the brackets I I and projecting rearwardly and downwardly from the rear edge of the bed.

I claim as my invention:

1. An action for a piano of the vertical string type having, in combination, a horizontal key bed, a key fulcrumed thereon and having a capstan projecting upwardly from its rear end, a generally horizontal main rail supported above said bed and extending transversely of said key, said rail being inclined downwardly and rearwardly relative to the bed, a hammer swingable in a vertical plane and having a shank with a butt at its lower end pivotally supported on and adjacent the rear edge of said rail, said butt having a knuckle adjacent said shank facing upwardly and forwardly, a whip in the form of a bellcrank pivotally supported intermediate its ends from the forward edge of said rail and having upstanding and horizontal arms, the horizontal arm overlying and bearing downwardly against said capstan, a jack fulcrumed on said upstanding arm and extending horizontally and rearwardly along the top of said rail with its free end engaging said knuckle, a catcher on the upper end of said shank and on the side of the latter opposite hammer, and a back check engageable with said catcher and supported from the upper end of said upstanding whip arm.

2. An action for a piano of the vertical string type having, in combination, a key mounted to swing about a horizontal axis and having a capstan on its rear end, a generally horizontal main rail mounted behind and extending transversely of said key with its rear edge disposed below and behind its forward edge, a hammer swingable in a vertical plane and having a shank with a butt at its lower end pivotally supported on and adjacent said rear rail edge, said butt having an upwardly and forwardly facing knuckle, a bellcrank pivoted intermediate its ends on and adjacent the forward edge of said rail and having upstanding and horizontal arms, the latter overlying and bearing downwardly against said capstan, and a jack fulcrumed on the upper end of said upstanding arm and extending horizontally and rearwardly along the top of said rail with its free end engaging said knuckle.

3. An action for a piano of the vertical string type having, in combination, a horizontal key bed, a key fulcrumed thereon and having a capstan on its rear end, a main rail supported above said bed behind said key, a hammer swingable in a vertical plane and having a shank with a butt at its lower end pivotally supported by said rail behind the latter, said butt having an upwardly and forwardly facing knuckle, a bellcrank pivoted intermediate its ends on said rail and having arms one projecting upwardly and the other horizontally and forwardly from the bellcrank pivot, the horizontal arm overlying and bearing downwardly against said capstan, and a jack lying generally horizontally and fulcrumed on said upstanding arm with its free end engaging said knuckle.

4. An action for a piano of the vertical string type having, in combination, a key swingable about a horizontal axis, a stationary main rail supported above said bed behind said key with its transverse dimension elongated and disposed generally horizontally, a hammer swingable in a vertical plane and having a shank with a butt at its lower end pivotally supported on and adjacent the rear edge of said rail and providing a knuckle, a bellcrank pivotally supported at the forward edge of said rail and having one arm overlying and actuated from the rear end of said key, said bellcrank also having an upright arm, and a jack fulcrumed on said upright arm and extending generally horizontally with its free end engaging said knuckle.

5. An action for a piano of the vertical string type having, in combination, a key swingable about a horizontal axis, a main rail supported above said bed behind said key, a hammer swingable in a vertical plane and having a shank with a butt at its lower end pivoted on said rail, a whip pivoted intermediate its ends on said rail with one end projecting generally horizontally over said key and having bearing engagement with the rear end of the key, the other end of the whip extending upwardly from the whip pivot, and a jack fulcrumed on said last mentioned arm with its free end projecting rearwardly and engaging said butt to actuate said hammer in response to depression of said key.

6. An action for a piano of the vertical string type having, in combination, a horizontal key bed, brackets supported on and fastened to said bed behind said keys and extending upwardly and rearwardly therefrom to provide a generally horizontal intermediate portion and forward and rear arms upstanding therefrom, a main rail fastened to the underside of said portion, hammers and whips pivotally supported by said rail with jacks interconnecting the two, an auxiliary rail supported by said rear bracket arms and constituting a cushioned rest for the shanks of said hammers, movable string dampers, and a third rail constituting a rest for said dampers and supported by said rear bracket arms.

7. An action for a piano of the vertical string type having, in combination, a hammer swingable in a vertical plane and having a forwardly and upwardly facing butt knuckle at its lower end, a generally L-shaped whip having horizontal and vertical arms respectively projecting forwardly and upwardly, said whip being swingable about a pivot disposed adjacent the intersection of said arms and in front of the hammer pivot, a jack pivotally supported at the free end of said upstanding whip arm and extending rearwardly and generally horizontally, the free end of the jack engaging said knuckle, and a key having its rear end underlying said horizontal whip arm and having bearing engagement therewith.

8. An action for a piano of the vertical string typ having, in combination, a hammer swingable in a vertical plane and having a butt knuckle at its lower end, a whip swingable about a pivot disposed in front of the hammer pivot and having arms respectively projecting forwardly and upwardly from the whip pivot, a jack pivotally supported at the free end of said upstanding whip arm with its free end engaging said knuckle, and a key having its rear end underlying said forwardly projecting arm and arranged to actuate the latter.

9. An action for a piano of the vertical string type having, in combination, a key swingable about a horizontal axis, a main rail disposed behind said key, a hammer swingable in a vertical plane and having a shank with a butt at its lower end pivotedon said rail, a whip pivoted on said rail in front of said hammer and having three arms respectively projecting upwardly, downwardly, and forwardly from the whip pivot, said forwardly projecting arm being actuated by said key, a jack pivoted on said upwardly extending arm and engageable with said knuckle to actuate said hammer, a damper actuating lever extending generally horizontally beneath said rail and pivoted intermediate its ends on a mounting separate from the rail, an arm upstanding from the rear end of said lever and carrying a string damper, and a 'spoon projecting rearwardly from said downwardly projecting whip arm and overlying th forward end of said lever to actuate the latter.

10. An action for a piano of the vertical string type having, in combination, a key swingable about a horizontal axis, a main rail disposed behind said key, a hammer swingable in a vertical plane and having a shank with a butt at its lower end pivoted on said rail, a whip pivoted on said rail in front of said hammer, a whip pivoted on said rail and actuated by said key, a jack pivoted on said rail and engageable at its free end with said knuckle, a lever disposed below said rail and pivoted on a mounting separate from said rail so as to permit of detachment and removal of the rail independently of the lever, means on said whip adapted for bearing engagement with said lever to actuate the latter, and a string damper carried by the rear end of said lever.

11. An action for a piano of the vertical string type having, in combination, a hammer swingable in a vertical plane and having a butt knuckle at its lower end, a jack, a whip swingable about a pivot disposed in front of the hammer pivot a distance approximating the length of said jack, arms on said jack respectively projecting forwardly and upwardly from th whip pivot and substantially alined with the latter, said jack being pivotally supported at the free end of said upstanding whip arm with its free end engaging said knuckle, and a key having its rear end underlying said forwardly projecting arm and arranged to actuate the latter.

CHARLES H. DASENBROOK.

Images