US3040614A - Drop type piano action - Google Patents

Description

June 26, 1962 H. G. BEHNING DROP TYPE PIANO ACTION 2 Sheets-Sheet 1 Filed Sept. 16, 1960 @en ALM-J ,d+ um f//k Eh en OO MMO @w .u Om w/ OO June 26, 1962 H. G. BEHNING DROP TYPE PIAN@ ACTION 2 Sheets-Sheet 2 Filed Sept. 16, 1960 NYENDTOK/ New vj C3. ehvkgyg ALM/(MJ, pm

QAw-reruoxsY/ United States Patent O Illinois Filed Sept. 16, 1960, Ser. No. 56,403 10 Claims. (Cl. 84-240) This invention relates toa piano laction of the drop type in which part of the .action is disposed below the level of the keys and the actuating motion is transmitted through an upright pull link pivotally joined at opposite ends to the rear end of the key lever and the free end of the whip. The invention is `directed more particularly to the pivotal `and detachable coupling of the pull link land the key lever through the medium of a `grommet composed of resiliently yieldable material such as rm rubber.

The general object is to correlate the construction of the grommet with the rear end of the key in a novel manner such as to substantially red-uce the time required to couple the key levers to the pull links and also facilitate disassembly and reassembly during releveling of the keys in the initial manufacture of the piano or after service use.

'Ilhe invention also resides in the-novel construction of the grommet and the manner of its coaction with the pull link to perform the foregoing new functions.

Other objects and advantages. of the invention will become apparent from the following. detailed description taken in connection with the yaccompanying drawings, in which FIGURE l is `a fragmentary vertical sectional view of a piano action embodying'the novel features of lthe present invention.

FIG.l 2 is a perspective view of the notched rear end of the piano key. Y

FIGS. 3 and 4 are `fragmentary sections taken respectively along the lines 3 3 yand 4-4 of FIG. l.

FIG. 5 is a longitudinal section of the rubber grommet.

(FIGS. 6 and 7 are fragmentary sections of ya 4part of FIG. l illustrating successive steps in coupling the key to the pull link of the action.

FIG. 8 is a fragmentary section taken along the line 8--S of FIG. 7.

FIG. 9 is Ia fragmentary View similar to FIG. 6 illustrating the manner of uncoupling the .key yand the pull link. l

In `a piano action shown in the drawingsl for purposes of illustration, the pull link indicated generally lat 10 is arranged to transmit the actuating cr upward movement of the rear end of a key 11 to .a whip lever 12 liur throwing a hammer 13 against `a piano string 14. The key is,

-apertured -at 15 vintermediate its ends to telescope down over a pin 16 upstanding from a pad 17 on which the key is fulcrumed in the usual way on .a balance rail 18 with the rear end of the key normally resting on ya pad 19 extending along the rear edge of the key bed 20.

The link 10 includes a lower part 21 made of wood and pivotally joined to the forked end of the whip 12. The upper part of the link is Va metal screw 22 having a slotted head 23 and an elongated shank 24 threaded at its lower end and screwed into `a hole in the upper end of the wooden part 21 in Iaxial alinement with the latter.

The key motion is transmitted to theflink through a fork 25 secured tothe key and having laterally spaced legs 26 prjecting from the rear end of the key and straddling the shank of a screw immediately below the head 23. Herein, the fork is a metal plate 32 fastened on top of the key by Ia screw 27 and a lug `28 embedded in the wood of the key. Beyond the key end, the plate is 3,040,614 Patented June 26, 1962 ice notched as indicated-at 29 to form the legs 26 whose opposed edges 30 at their outer ends are substantially parallel .and define between them .a relatively narrow slot. At their inner ends, the edges 30 are arcuate in shape and define a generally Icircular hole 31 somewhat larger than the width of the slot 30.

yIn yaccordance with the present invention, the fork 25 is lpivotally and detacri'ably coupled to the screw 22 of the pull link through the medium of a sleeve-like grommet 33 of resiliently yieldable material telescoped on the screw shank inv abutment with the head 23 and of a special construction `correlated with the notch of the fork 25 so as to enable coupling land uncoupling of the two to be achieved by manipulation of thekey lever 11 as an incident to mounting the latter on or removing the same from the fulcrum pin 16.

Preferably, thegrommet is molded .and composed of "relatively .firm rubber, preferably about 50 asmeasured by a Shore Durometer, and comprises a sleeve 34 several times las long as the thickness oi' the fork 25 and having ia central hole 35 of-about the same diameter as the shank 24 of lthe screw so that the grommet may beslid easily along the shank to bring an end ange 36 on the grommet into abutment with the underside `of the screw head 23. The flange is somewhat larger than the screw head .and restsatly against the Vtop'surface of the fork 25 which is bentupwardly so as to be disposed perpendicular to the pull link 10 in the idle position of the latter when the key lever-is released.

The wall thickness` of the sleeve is about /s of an inch over the upper halt .-portion whose outer suriace 37 is generally cylindrical having a diameter slightly less, by [about 0.005 of aninch, than the hole 31 in the fork 25. Thus, when the grommet is disposed in the hole with the flange 36 .abutting the underside/of the screw head, the rubberV of the grommet wall is compressed slightly thus creating additional resistance to sliding of the grommet along the shank and away from the screw head under the inertia of the action parts when the motion thereof is arrested as the hammer 13 comes against the stri-ng 14. In the present instance, the resistance to the sliding of the grommet away from the screw head is increased by an enlargement formed on the shank of the screw and spaced axially away from. the head 23 a distance preferably only .slightly greater than the thickness of the forkV -be apparent that the ribs produce a further increase in the external diameter below the fork 25 as shown in FIGS. 3 and 4, thus forming in eiiect a groove 39` in which the deiiningV edges of the fork hole are seated thus further increasing the resistance to displacement of the fork along the shank so as to maintain the grommet in abutment with the screw head under the forces which accompany the normalV operation of the piano action. Owing however to the radial yieldability of the grommet wall 34, the fork 215 may be shifted axially away from ythev liange 36 or transversely of the 'shank axis during coupling or uncoupling of the two. This is permitted by compression of the rubber of the sleeve wall thus allowing the sleeve to pass through the narrower slot 30.

The lower or free end portion of the grommet is preferably shaped to facilitate and actually pilot the insertion of the grommet into the yhole 31' of the fork. For this purpose, the ydiameter of the lower half portion is decreased progressively being substantially at the longitudinal center of the sleeve so as to taper the surface 40 i down to a diameter of about 1%4 of an inch at the lower end of the sleeve. It will be observed that this diameter is substantially less than that of the fork hole 31 so that the small end of the grommet may easily be guided into the hole.

With the grommet 33 constructed as above described in relation to the notch of the fork 25 on the key and the size and shape of the screw shank, the coupling of the fork to the pull link and uncoupling therefrom is effected in the following manner. After the action proper has been mounted in a piano case, the keys 11 are mounted on the bed 20 by resting the keys one by one on the pad 19 as shown in FIG. 6 and swinging the pull link to pass the screw shank through the slot 30 of the fork. Next, the key is swung downwardly to enter the pin 16 through the key hole and settle the key on its fulcrum 17 at the same time guiding the tapered lower end of the sleeve 34 into the hole 31 as shown in FIG. 8 and in full in FIG. 7. The assembly is then completed by striking a sharp blow on the free end of the key to raise the key to the position shown in phantom in FIG. 7. During this motion and due to the inertia of the action parts, the fork is slid upwardly along the sleeve thus compressing the rubber as it passes the enlargement 38 and comes into abutment with the flange 36 of the grommet. The edges of the fork thus become disposed in the vgroove 39 and the fork is thus held effectually against axial displacement relative to the screw shank.

With the key and pull link thus coupled together, it will be apparent that the flange 36 constitutes a yieldable cushion between the fork and the screw head for trans- 1 mitting the key motion to the whip 12 while allowing for relative pivotal movement of the key and link by yielding of the rubber of the grommet. The coupling is maintained effectually in all positions of the parts in normal service use because of the compression of the grommet wall within the hole 31 of the fork combined with the enlargement of the sleeve 34 below the fork by the rib 38. The pivotal movement between the link and the key which accompanies the normal striking and release of the key is accommodated by yielding of that part of the rubber which joins the screw shank and the fork.

At the same time, the improved grommet connection described permits convenient uncoupling and separation of the key from its pull link and recoupling of thektwo by simple manipulations of the key in lifting the key off from and replacement of the same on the fulcrum guide ing. The portion of the plate 32. adjacent the hole 31 first comes against the forward edge of the gromrnet flange 36, as shown in FIG. 9, after which the flange acts as a fulcrum as the raising of the key is continued to swing the notch 29 downward and7 by compressing the sleeve 34, cause the latter to pass outwardly through the slot 30 thus freeing the key fork from the grommet. To recouple the key and pull link, the manipulation of the key and pull link as above described is repeated.

It will be apparent from the foregoing that by the novel construction of the coupling grommet and the manner of its correlation with the notch of the key fork 25 a new and simplified mode of assembling piano actions is achieved. That is to say, a partial and easy prel'uninary assembly (FIG. 7) is started a's an incident to placing the key on its fulcrum. Then, the final assembly is effected simply by striking a downward blow on the free end of each key, the vsame as in normal service use of the piano. Removal and replacement of the keys to level the initial manufacture or service use is similarly facilitated. As a consequence, the overall cost of initial manufacture of a piano of the drop action type as well as the later servicing thereof is reduced substantially as compared with that of prior constructions.-

This application discloses subject matter common Yto and generically claimed in copending applications of Phil lip I. Roehrig, Serial No. 787,230, filed January 16, 1959, and Harold R. Anderson, Serial No. 808,477, filed April 23, 1959, no claim being made herein to such common subject matter.

I claim as my invention:

l. In a piano action or" the drop type, the combination of, a manually operable key lever fulcrumed intermediate its ends, a fork rigid with and projecting from the rear end of said key and having a rearwardly opening notch comprising a generally, circular hole at the closed end of the notch communicating with a narrower parallel sided slot at the open end of the notch, an elongated endwise reciprocable link including a metal shank having a head thereon, a sleeve of resiliently yieldable material several times as long as the thickness of said fork snugly telescoped on said shank and projecting through said hole and compressed by the defining edges thereof, and a flange formed on the upper end of said sleeve and abutting against the underside of said head and the top of said fork, said sleeve being dimensioned for insertion endwise down through said hole and also for movement laterally out of the notch through said slot.

2. The combination as defined by claim l in which the width of said slot is large enough to permit shifting of the sleeve laterally out of said notch by compression of the material of the sleeve wall as it passes out through the slot.

3. The combination as defined by claim l including an enlargement on said shank disposed below said notch and within said sleeve and acting to increase the outside diameter of the sleeve and form y'with said flange a shallow groove in which the legs of said fork are seated and restrained against axial displacement relative to the sleeve.

4. The combination as defined by claim l in which the sleeve below said fork is reduced to an outside diameter smaller than said hole.

5. The combination as defined by claim 4 in which the lower end portion of said sleeve below said fork is tapered down to a diameter smaller than said fork hole.

6. In a piano action of the drop type, the combination of, a manually operable key lever fulcrurned intermediate yits ends, an elongated endwise reciprocable link having a head thereon, a sleeve of resiliently yieldable material snugly telescoped on said link and having a flange at the upper end larger than the vrest of the sleeve and abuting against the underside of said head, and a fork rigid with and projecting from the rear end of said key and having a rearwardly opening notch with the legs thereof straddling said sleeve and abutting the underswinging of said key lever about a fulcrum defined by theV edge of` said flange.

7. In a piano action of the drop type, the combination of, a manually operable key lever fulcrurned intermediate its ends, a fork rigid with and projecting from the rear end of said key and having a rearwardly opening notch, an elongated endwise reciprocable link having a head thereon, a sleeve of resiliently yieldable material several times as long as the thickness of said fork snugly telescoped on said link and projecting through said notch and compressed by the defining edges thereof, and a flange formed on the ,upper end of said sleeve and abutting against the underside of said head and the top of said fork, said sleeve being dimensioned for insertion endwise down through the closed end of said notch and also for movement laterally out of the notch by radial compression of the sleeve. f

8. In a piano action of the drop type, the combination of, a manually operable key lever fulcrurned intermediate 1ts ends, a yfork rigid with and projecting from the rear end of said key and having a rearwardly opening notch defined by a `generally circular hole at its inner closed i projecting through said notch hole' and held therein by they notch edges but compressible edgewise for movement out of the notch between said laterally spaced edges, and a flange formed on the upper end of said sleeve and abutting against the top of said fork,'said sleeve below i said fork tapering to a diameter-small enough to 'permit of endwise insertion of the sleeve into said hole.

9. In a piano action ofthe drop type, the combination t of, a manually operable key lever fulcrumed intermediate its ends, a fork rigid with and projecting from the rear end of said key and having a rearwardly opening notch den'ed by a generally circular lhole'at its inner closed end and laterally spaced edges located at the outer end .of the notch andv spaced closerk together than the diameter of said hole, an upright elongated endwise reciprocable link, a sleeve of resiliently yieldable material severaltimes as long as the thickness of said fork telescoped on said link, means onrsaid link holding said sleeve against endwise displacementalong the link, including a rib `formed on and extending around said link within said sleeve and having a diameter larger than f the internal Wall of the sleeve whereby to expand and grip said wall as an incident to insertion of the link through the sleeve, said sleeve projecting through said notch hole and held therein by the notch edges but compressible edgewise for movement out of the notch between said laterally spaced edges, and a flange formed on the up- Vper end of said sleeve and abutting against the top of said `mediate its ends, a fork rigid with and projecting from the rear end of said key and having aV rearwardly opening notch defined by a generally circular hole at its inner closed end and parallel edges located at the outer end of the'notch and spaced closer together than the diameter of said hole, an upright elongated` endwise reciprocable link, a sleeve of resiliently yieldable material several times as long as the thickness of said fork telescoped on said link, means on said link holding said sleeve against endwise displacement along the link, said sleeve projecting through said notch hole, and a ange formed on the upper end of said sleeve, said sleeve below said fork tapering to a diameter smaller than said hole to permit of endwise insertion of the sleeve into said y References Cited in the le of this patent UNITED STATES PATENTS Mason Dec. 3l, 1940 2,324,037 Socin July 13, 1943 2,548,890 Knoblaugh Apr. 17, 1951

Images