US1617300A - Piano key - Google Patents

Description

Feb. 8, 1927,' 3, GULBRANSEN PIANO KEY Fived Nov. 2, 1922 f 15 ao Patented Feb. 8, 1927.

lTUNITED STATES PATENT I OFFICE.

, CHRISTIAN GULBRANSEN, OF CHICAGO, ILLINOIS, ASSIGNOR TO GULBRANSEN COM- i PANY, A CORPORATION OF ILLINOIS.

PIANO KEY.

Application filed November 2, 1922. Serial No. 598,534.

My invention relites to piano keys, and

v particularly to improvements in keys for player pianos. o

jAy conventional practice-in grand piano playeI Construction is to operate .the piano actionby the player' action through'the medium of the piano keys, i. e., to place the Vstack of pineumatics below the level of they keys and to have the pneumatics operate the io piano actionv through the medium of fingers or rods'which push upwardly on the inner l.,.ends`of the piano 'keys. In this arrangement theplayer pneumatics must yoperate against the inertia and friction of the entire key, including the ivory faced finger ends constituting thekeyboard. It isthe fundamental object of the present invention to avoid the above disadvantages of operating the entire key, preferably byv articulating the key so that only the inner portion thereof will be actuated by the v pneumatics, the whole key, however, operat- 'iing in the usual way when operated by hand. The inner portion is of very small ",inertia and friction so that it imposes a minimum deterrenee to the operation of the player pneumatics. The articulated key also avoids the objectionable appearance of the numerous keys rising andfalling along 30 the keyboard during the operation of the player mechanism.

Othercbjects ofthe invention are concerned vwith the Aimproved form of joint for articulatingithe The joint must be easy working,` inexpensive and exceedingly compact because of the close nesting of the keys. Itis further-inore desirable that the articulated' portion of the .key which strikes the piano action move from substantially -H the same center and strike at substantially the. same radius when act-uated by the player action as when actuated during manual playing at the keyboard.

Referring to the accompanying drawing villustratinga preferred embodiment;

Figure 1 is a fragmentary sectional View through a key-bed, illustrating the use of my improved key; Q

Fig. 2 is a fragmentary elevational view of amodified form of joint; and

Fig. 3 is a plan view of the same.

The keys which are designated 6 in their entireties, are pivotally mounted on the bed 7 upon hinge pins 8. The ivory surf-.iced finger ends 9 play between the front board 11 and the strip 12 running along the edge of the bed 7. The vertical motion of the finger end of each key is guided upon an upright guide pin 10 which engages in a slotted felt-lined hole 10' in the linger end. This is all conventional practice and needs no detail description. It should be remarked, however, that the friction of the guide pin 10 in the hole 10, and the linger end 9 in the keyboard, is sufficient to support the key in its raised position against' the action of gravity.

The inner end of the key plays between the piano action, illustrated at 13, and the player action, illustrated fragmentarily at 14. The piano action 13 is operated by a capstan screw 15 striking the actuating member 16 and actuating the hammer 17 in the usual manner.

The stack of pneum'aticsil'el is supported below the bed 7, the finger extension 18 of each pneumatic 19 being adapted to engage a rod 21 passing upwardly through the guide block 22. The upper end of each rod 21 carries a. felt button 23 adapted to strike the inner end of the key and thrust thesame upwardly, upon the actuation of thelcorrespending pneumatic 19. I i

In the conventional construction the upward thrust of the rod 21 rocks the entire key about the vertical pivot pin 8. ln the present construction T divide the inner end of the key into upper and lower halves 2-1 and 25. The lower portion 25 is a. continuation of the vmain body of the key 6. The upper leaf portion 24 is a section sawed outlof the body of the key or otherwise conformed to complete the inner end of the key. This leaf section 24 has a depending tail piece 26 which overhangs the end of the key portion 25 and receives the impulse of the player pneumatic through button 23. The capstan screw 15 is carried in this leaf portion 24. Pivotal mot-ion of the leaf portion 24 towards and away from the key extension 25 is guided by a pin 20 which extends up through a slotted hole 30 in the inner 'end of the leaf portion. A felt washer 40 between the leaf portion and the key extension prevents noise on the return stroke of the leaf portion back against the key extension. The other end of this leaf portion 24; is hinged or jointed to the body of the key, preferably at a point adjacent to or coincident with the pivot-al axis of the key.

A sheet metal clip 27 embraces the top and both sides ofthe end of the leaf portion 24', being secured thereto by pins 28 extending through-andl riveted over on the sides of the 'clip. From this clip extends-two pivot arms 29, one on each side of the body of the key 6, and these arms have pivotal attachment to the body of the key upon a. pivot pin or pins 31. The pin 8 extends up through .an opening or slot 32.in.the key, which opening is in the nature of, a roundhole in the bottom of th'e key,.and an elongated slot at the top ofthe key. The key rocks on this pin over the convex supporting plate 33 which is mountedon the piano bed 7. This is the center of pivotal motion of the capstan screw 15 when the outer end 9` of the key is depressed. By extending the. two pivot arms 29 down into proximity. to! the intersection of the pivotpin 8 with the supporting plate 33, the leaf portion 24 will move from substantially thesame center of pivotal motion when actuated'4 by the plunger action. In Fig. 1. a single pivotpinl is passed through the pivotarms 29 and'body of the key alongside of the upright pivot pin 8. In Fig. 2 the arms 29 are each pivoted to the side of the key by individual short pivot pins 31, which. are disposed coincident with the axis of the pivot pin, but neither of which pass through the key.

In the operation of the player action 14 the upward motion of the player rod 21 strikes thetail end. 26, of the corresponding key and. raises the leaf portion 24, thereby imparting actuating motion toxthe piano action without having to overcome the inertia and friction of the key proper. The friction at.. the finger endV of the key holds this end up When theleaf portion 24 is raised.

I claim:

1. In a player piano, in combination, a pivot pinv and plate, a key element centrally supported thereby, said keyelement extending with undiminished cross section a short distance past said' pin, the cross sectionbeing then cut clown, a leaf lying on the element beyond said pin, a pivotal connection between leaf and element substantially on the axis of rotation of said element on its support, said leaf projecting beyond the end of said element, a pneumatic action, connections between said action and leaf engaging the projecting end of said leaf, a piano action, and an operating connection between said leaf and piano action.

2. In a player piano, in combination, a pivot pin and plate, a key element centrally supported thereby, said key element extending with undiminished cross section a short distance beyond said pin, the cross section being then cut down, a leaf lying on the element beyond said pin, and a pivotal connection between leaf and element substantially on the axis of rotation of said element on its support.

3. In a player piano, in combination, a piano action, a leaf, an operating connection between said leaf and said piano action, a key supporting said leaf and pivoted beyond the end thereof, an extension on said leaf pivoting it on an axis substantially in the same vertical plane as the key pivot, and a pneumatic action connected directly 'to saidleaf.

4.. In a player piano, in combination, a piano action, a leaf, an operatingl connection between said leaf and said piano action, a key supporting` sai-d leaf and pivoted beyond the end thereof, an extension on said leaf pivoting it on an axissubstantially the same as that of the key pivot, and a pneumatic action connected directly to said leaf.

5. In a player piano, in combination, a piano action, a leaf, an operating connection between said leaf and said piano action, a key supporting said leaf and pivoted beyond the end thereof, an extension on said leaf pivoting it on an axis substantially in the same vertical plane as the key pivot, and a pneumatic action connected directly to sai-d leaf, said extension comprisingr a clip having an arm extending beyond the end of the leaf.

In witness whereof, I lhereunto subscribe my name this 18 day of October, 1922.

CHRISTIAN GULBRANSEN.

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