US2040304A - Key and key frame for grand pianos - Google Patents

Description

2&40304 May E2, W36. F. L. GEORGE KEY AND KEY FRAME FOR GRAND PIANOS Filed June 7, 1954 w a A? r a MN Patented May 12, 1936 UNITED STATES PATENT OFFICE KEY AND KEY FRAIWE FOR GRAND PIANOS 21 Claims.

My invention relates to a construction of a key frame which is attached to a key bed of a piano and on which is mounted the balance rail and the pin on which the key is fulcrumed. Also, my invention relates to the particular construction forming a fulcrum for the key.

Another feature of my invention relates to an adjustable forward end of the key frame on the key bed and a construction for limiting the stroke of a key during the playing of the piano.

In order to clearly understand the features and objects of my invention, the standard present practice is described briefly as follows in which some of the defects of this practice are set forth:-

In the present practice, the keys are seated on a cloth punching on the balance rail of the key frame which produces an unnatural movement of the key as it rotates up and down under the touch of the performer. The motion so developed is not the natural arc of a circle, as it should be. The key rests upon a flat cloth punching and this contact becomes the location or starting point of the arc of the circle because the key is struck at the top, its front end, and the fulcrum being at the lower side of its center, then, as the piano action, which the key moves upwardly, being placed at the top of its rear end, a rocking movement is produced throughout the key and also its parts. With this construction of the key with its fulcrum on its bottom edge by a flat cloth punching, when the key is struck it transfers its contact across the top of the surface of the punching onto the front edge of the punching and back again.

Another objection to the present construction relates to the tedious operation of adjusting the level of the top of the ivory keys. For instance, the key to be raised or lowered must first be lifted from the balance rail pin and a cloth punching placed over this pin on the balance rail then a paper punching of which there are several thicknesses ranging from that of tissue paper to heavy card-board, is placed on the balance rail on top of the cloth punching on this rail. The number of punchings so placed and their various thicknesses is a matter of skill on the part of the tuner or adjuster and varies in accordance with the distance the key must be raised or lowered. The key is then replaced on the frame and tested as to its height alongside its neighbors and if found to be still too high or too low, the particular key must be removed and the entire aforementioned operation repeated, and frequently this adjusting must be repeated many times on a single key before its exact level is obtained.

Then, when found to be accurately level, the key must be again removed, all of the punchings, both cloth and paper must be removed from the pin, turned bottom side up and reversed so that the cloth punching will be uppermost, for, if the bottom edge of the key rested upon the paper punchings there would be created a rasping or grating action against the wood bottom of the key. Frequently the operator must go through this adjusting operation upon the entire keyboard of eighty-eight keys.

Another ineffective feature of the present key frame construction relates to its front rail upon which the bottom front end of the key strikes when brought to rest after the stroke of the player. It is a common construction to use a front rail guide pin upon which the key moves up and down when in motion. This has a cloth punching fitted upon it similar to but larger than the one on the balance rail pin and the distance from the bottom of the key at the front when at rest, to the top of this punching must approximate three-eighths of an inch when properly regulated. Therefore, when the leveling of the keys on the key rail as above described has been completed, then the stroke of the keys at the front rail bearing must be tested as to their dip or stroke and when found to vary from the necessary three eighths of an inch, must be regulated with different thicknesses of paper and card-board punchings somewhat in the manner above described in leveling the keys on the balance rail. Then, after the key leveling work is completed and the action is made fast to the key frame, it is impossible to remove a key from a key frame to make a further leveling at a later date without removing the entire key action which must be unscrewed and removed from the key frame.

Another defect of the present practice is found in the method of boring and mortising a key in its fittings, bearings and seatings on the balance rail pin. In this present practice, the key is bored downward from the top at the exact place where it is to pass over the balance rail. This hole is bored larger than the pin until within one-eighth of the bottom of the key and for the remaining one-eighth, it is bored to exactly fit the balance rail pin. The large hole that is bored through the key leaves the outer walls of the key so thin that occasionally under a heavy blow by a performer the thin wall of the key at this point collapses, thus the key becomes wrecked. Moreover, the small hole at the bottom of the key which hugs the balance rail pin often enlarges under use and in removing the keys for repairs and leveling. When this hole fitting on the pin is enlarged or spread by pressure against the balance rail pin the key thereafter becomes wobbly and unsteady upon the pin under the touch of the performer and must remain so as there is no way of successfully reducing such an enlargement.

It is the present practice to, on top of the key directly above the large hole so bored, mount a long cap which is fitted with a felt lined slot whose sides are fitted to just hug the top end of the balance rail pin; as the walls of this slot slide along the balance rail pin when the key is being used and owing to the angle of the majority of the keys, friction on one or the other of these walls at the top of the balance rail pin soon wears the felt wall and wears a groove in the side of the wood wall to which the felt is glued. This wood surface rattles against the top of the pin and also allows the keys to lay over sidewise at their tops and thereby throws the entire key board out of alignment.

Among the objects of my invention is the development of the construction overcoming the above mentioned defects and having an improved balance for the key which will allow a simplified procedure for regulating the height of the key, and in addition, the changed construction to regulate the throw or stroke of the key at its front end.

A main object and feature of my invention therefore, is attaching to the key-bed a key frame, which frame has the balance rail secured thereto and extending upwardly from the balance rail there is a balance pin.

The key is formed with a mortise from its under surface upwardly and a hole or perforation axially aligned with the mortise. A regulating screw extends through this hole and has a bearing on the top of the balance rail pin with a punching of leather between the pin and the screw. This construction locates the fulcrum for the key at the center of the key considered between its top and bottom surfaces and therefore the key swings in a true circular are when struck by the fingers of the performer. Moreover, on account of the screw being threaded in the hole of the key from the top, this may be regulated by either turning the screw further in the key or threading it out to obtain the proper level for the key and the adjacent keys.

The balance rail pin is oval in cross section in the portion in the mortise. The sides of the oval section engage cloth pads glued on the side of the mortise which is in the form of a slot. When the key is oscillated the pads bear against the side of the balance rail pin. The key is first fitted to the balance rail pin with the short axis of the oval being transverse to the slot of the mortise but if the cloth pads in the mortise become worn the pin may be slightly rotated to bring the correct contact with the sides of the pad until it has been rotated one quarter turn, bringing its long axis transverse to the slot of the mortise.

A further object and feature of my invention for adjusting the stroke or throw of the key is by forming a key frame with a type of hinge. This key frame is made of wood and has a notched-out section forward of the balance rail forming a hinge. The front rail is attached to the forward end of the key frame. A counter-sunk hole is bored through the front rail and a smaller hole for a screw through the forward end of the key frame. A screw is inserted through these holes and the head of the screw engages the countersink and the screw is threaded into the key bed rail. In order to hold the screw properly seated, a threaded tubular escutcheon is threaded in the counter-sunk bore hole and bears on the head of the screw, but the screw may be adjusted by a screw driver inserted through the tubular escutcheon to regulate the height of the forward end of the key frame above the key board and when this is regulated the key frame pivoting on its hinge, the escutcheon is screwed tight against the head of the screw and maintains this adjustment.

The screw inserted through the hinged portion of the screw frame is thus used to raise and lower the front end of the key frame relative to the key bed rail.

My invention is illustrated in connection with the accompanying drawing, in which:

Fig. 1 is a side elevation of a key, the key frame and balance rail with portions shown in section, the key bed being in section.

Fig. 2 is a side elevation of the key frame showing the balance rail with parts being shown in section and the key bed in section.

Fig. 3 is a plan taken in the direction of the arrow 3 of Fig. 2 showing a portion of the key frame narrowed to illustrate the principle of construction.

Fig. 4 is a horizontal section on the line 4-4 of Fig. l in the direction of the arrows.

In my invention the key bed is indicated by the numeral II and upon this is mounted the key frame [2 which has a center section l3, the rear half l4 and the front half IS. The rear half has a rest rail IE mounted thereon with a cloth pad I? secured at the top of this rest rail. The front end of the key frame is provided with a cut-out notch 20 forming what I term a hinge. The front i rail 2! is secured to the end of the front half I5 of the key frame. This forward end is thus adjustably mounted as to the key bed by providing the front rail with a counter-sunk perforation or hole 22 having the countersunk shoulders 22 and The manner of mounting or fulcruming the key 25 is as follows:

The balance rail 26 has a hole 21 formed therein to which is attached the balance rail pin 28. This pin has a lower cylindrical section 29 fitting tightly in the hole 21, an oval section 30. and a top cylindrical end 3| which is of the same diameter as the lower end 29. The key is provided on its under surface with a mortise 32 and extending from the upper end of this mortise there is a hole 33 in which the upper end 3| of the pin has a snug fit. A regulating screw 34 is threaded in its upper portion 35 threaded in the hole 2"! and has a lower cylindrical portion 36 forming a snug fit in the hole 33 and there is a fulcrum punching of leather 31 between the end of the screw and the top end 3| of the balance rail pin 28. The screw is provided with a screw driver kerf 38.

In the usual construction of my keys, the mortise is about three-ei hths of an inch deep and the leather punching 3'! is located directly in the center of the key considered between its top and. bottom. In order to adjust the key either up or down in regard to the balance rail pin, the screw may extend to a further distance in the hole 33. The oval section 3!! of the balance rail pin should be such a length that under no conditions of adjustment will it engage the upper end or bottom of the mortise 32 but will allow the upper end 3| to extend upwardly in the hole 33 when it is necessary to lower the key in reference to its fulcrurn. The screw 34 is only threaded a portion of its length to facilitate assembly and adjustment of the screw. The tubular escutcheon 4D is threaded in the hole or bore 22. This escutcheon has a screw driver kerf 4|.

This pin 42 has a stop pad 42 at its base and such stop pad thus rests on the front rail 2|. There is a pin 42 and stop pad 42' for each key. Hence each key when depressed contacts its own stop pad 42'.

The manner of adjusting the dip or stroke of the key is as follows:

If it is desired to give a greater stroke, a screw driver may be entered through the tubular escutcheon 4B and engage the kerf in the head of the screw 24, this screw then being threaded further into the key bed rail and drawing the front end M of the key frame downwardly towards the key bed rail 5|. In this action the forward end l5 of the key frame pivots on its hinge portion 20. The screw 24 may be screwed either up or down to increase or decrease the distance between the forward end of the key frame and the key bed rail 5|. The escutcheon 4|! should always be maintained in close contact with the head of the screw. Thus, when the screw is raised in the key bed rail it will elevate the front end of the forward section of the key frame.

The key frame |3 having the rear half l4 and the front half l5 may be made much in the standard manner and for a keyboard of eighty-eight keys I find it satisfactory to make saw cuts 1ongitudinally of the two end transverse members of the key frame, and also to make similar saw cuts in the intermediate transverse portions of this frame. It is only necessary to have two screws similar to 24 with the escutcheon 40 at the ends of a hinged section of the forward portion of the key frame. The cut-out or grooved portion forming the hinge need only be formed in the movable parts of the transverse member of the forward key frame section. Thus, for a key board of eighty-eight keys I usually employ four adjustable hinged forward key frame sections, each having about twenty-one or twenty-two keys mounted thereabove.

The front end of the key bed is provided with a cut-out section 50 in which is inserted a longitudinal rail 5|. A short slot 52 is provided in the key bed and through this extends a screw 53 threaded in the rail 5 I. A coiled spring washer 54 surrounds the shank of the screw and fits underneath the screw head engaging the bottom of the key bed.

The screws 24 in the forward end of the key frame are thus secured into the rail 5| and held therein by the escutcheons. These screws are not touched when the action is removed from the key bed. The key frame with the keys may be removed by removing the screws 53 of which three are used, one at each end and one at about the center of the key board. This allows removal of the rail 5| with the key frame of the keys and does not disturb the adjustment of the outer forward end of the key frame.

In my construction of the key frame |2 which has the hinge feature indicated by the numeral 20 so that the front half of this key frame may be raised and adjusted as to the key bed H, I make use of the general principles of the standard construction of piano key frames. This standard construction employs a front rail similar to 2| which rests on the strips I5 which extend parallel to the keys to the rest rail [6 having the pad I! thereon, as such rest rail usually extends longitudinally of the key board and parallel to the front rail. The balance rail 26 usually rests on the elements l4 and I5 of the key frame and also extends longitudinally of the key board. This standard construction therefore forms a key frame but by my improvement I form the cut-out notch 20 in the strips l4 and I5 of the key frame and which extend parallel to the keys and below such keys, and I form saw-cuts, or the like,'in the forward half l5 of the strips. This construction then forms the key frame, with usually four adjustable, hinged forward sections, and each of these sections may accommodate about twentyone or twenty-two keys, the four sections therefore accommodating the keys of the full key board. Thus, when one of these sections is adjusted either up or down, that is, away from or toward the key bed I I, by the adjusting screws 24, I make the adjustment for a group of keys, about twentyone or twenty-two in number, all at one time. Instead of forming the saw-cut in the forward portion of the key bed strips l4 and IE to form the separate adjustable forward half sections of the key frame I may employ strips such as M and I5 illustrated in Fig. 3 which are comparatively narrow. The front rail 2| extends from one of the forward strips M to the next strip of a movable section, then as the rear half M of each section of the key frame is rigidly secured to the key bed in the usual manner by screws, the front half of each section of the key frame with the front rail 2| may be adjusted as to the key bed by the screw 24.

My invention therefore comprehends a manner of weakening a section of the key frame between the balance rail and the front of the piano whereby the front portion may be regulated as to its height above the key bed and thereby an adjustment made for the correct spacing of the keys when in their inoperative position above the front rail of the key frame and thus regulating the downward stroke of the keys in a group. The adjustment screws 24 connect to the key bed rail 5| which is removable and therefore, after disconnecting the rear portion of the key frame from the key bed of the piano, the whole key frame with the key bed rail 5| may be removed as a unit and likewise replaced as a unit.

Various changes may be made in the details of construction without departing from the scope of the invention as defined by the appended claims.

I claim:

1. In a piano, the combination of a balance rail pin, a key having an elongated mortise in its lower surface and a hole extending from the mortise to the top, the said pin having its upper portion fitted snugly in the lower portion of the hole, and an adjusting means extending through the hole from the top and forming with the upper end of the said pin a fulcrum for oscillation of the key located between the upper and lower surfaces of the key.

2. In a piano, the combination of a balance rail pin, a key having an elongated mortise in its lower surface and a circular hole extending from the mortise to the top of the key said pin passing through the mortise and having a snug fit in the hole, a screw threaded in said hole and having means for rotating the screw at the top, the lower end of the screw forming with the upper end of the said pin a fulcrum for oscillation of the key located between the upper and lower surfaces of the key.

3. In a piano, the combination of a balance rail, a balance rail pin secured therein and having a cylindrical upper end, the key having an elongated mortise in its lower surface and a cylindrical hole extending from the mortise to the top of the key, a screw having an upper threaded portion and a lower cylindrical portion fitted in the said hole, the cylindrical portion of the pin extending into the lower part of the said hole and having a snug fit therein and forming with the lower end of the screw a fulcrum for oscillation of the key located between its upper 1nd lower surfaces.

4. In a piano, the combination of a balance rail having a cylindrical hole, a balance rail pin having a lower cylindrical section inserted in said hole, a section thereabove having a portion elongated in cross section with a lesser and a longer diameter and a cylindrical top, a key having a mortise extending upwardly from its lower surface in the form of a longitudinal slot and pads on opposite sides of the slot and a cylindrical hole extending upwardly from the mortise to the top of the key, the upper end of the pin being inserted in the lower part of the said hole and having a snug fit therein, and means inserted in the hole of the key from the top for forming an adjustable fulcrum for the key on the top of the said pin.

5. In a piano as claimed in claim 4, the means forming the adjustable fulcrum comprising a screw having a screw driver kerf at the top, a threaded section threaded in the said hole, a lower cylindrical section, and a resilient pad between the lower end of the screw and the top of the pin.

6. In a piano, the combination of a key bed, a key frame mounted thereon, a balance rail on the key frame, a balance rail pin secured to the balance rail, a key having a mortise extending upwardly from its lower surface and a hole between the mortise and the top of the key, the upper end of the pin being cylindrical and fitting snugly in the lower portion of the said hole, a screw inserted in the said hole of the key from the top, a resilient pad between the lower end of the screw and the top of the pin, the forward portion of the key frame having a cut out section forming a hinge, a pad supported on the forward end of the key frame, a counter-sink bore at the forward end of the key frame, a screw in the bore having an enlarged head engaging the countersink, means to attach the screw to the key bed, and a tubular escutcheon in the counter-sink bore engaging the top of said latter screw whereby the screw in the key may adjust the fulcrum of the key and the height of the key relative to the key frame without removing the key and the adjustment of the screw at the forward end of the key frame may adjust the stroke of the key.

7. In a piano having a key bed, a key frame having a rear portion attached to the key bed, a balance rail, a key fulcrumed on the balance rail, the forward portion of the key frame having [a stop pad to engage the key when depressed,

combined with means forming a hinged section of the key frame forward of the balance rail, and means to adjust the height of the forward front edge of the key frame relative to the forward front side of the key bed, the forward portion of the key frame being divided into sections extending longitudinally of the piano and each section extending under a number of keys, the forward end of each section being independently adjustable as to the key bed independently of the next adjacent section whereby any one section of the forward portion of the key frame may be adjusted relative to a plurality of keys.

8. In a piano having a key bed, a key frame thereon, a balance rail extending longitudinally of the key frame and having a plurality of keys fulcrumed thereon, the rear portion of the key frame being secured to the key bed, the forward portion of the key frame having a front rail with a stop pad material for the keys combined with the forward portion of the key frame in front of the balance rail having a hinge construction, and means to adjust the height of the forward portion of the key frame and front rail in reference to the key bed whereby the single adjustment adjusts the stroke of a plurality of keys at one time, the means to adjust the forward portion of the key frame including the key frame having a perforation, a screw extending therethrough, means to attach said screw to the key bed and a tubular escutcheon in the front rail engaging the head of the screw.

9. In a piano having a key bed, a key frame mounted thereon and having a balance rail extending longitudinally of the key frame, the portion of the key frame rearwardly of the balance rail being attached to the key bed, a plurality of keys fulcrumed on the balance rail combined with key bed rail 5| secured to the front of the key bed H and extending longitudinally thereof, the portion of the key frame l5 forward of the balance rail being divided into sections, each section having a hinge construction and a front rail 2| extending longitudinally of the section, the front rail having a plurality of stop pads, one for each key, and means to adjust the forward portion of each key frame section as to its height above the key bed and thereby adjust the stroke of a plurality of keys by adjusting the key frame section underneath such keys.

10. In a piano as claimed in claim 9, the means to adjust the sections of the key frame comprising, providing a slot 52 in the key bed, a screw 53 extending through said slot and attaching threaded into the key bed rail, the front rail of each key frame section having a plurality of tubular escutcheons 40 threaded therein, each escutcheon being in alignment with one of the second screws 24 connecting the forward portion of the key frame to the key bed rail and contacting the head thereof.

11. In a piano, the combination of a balance rail, a balance rail pin secured thereto and having a cylindrical upper end, a key having a longitudinal mortise extending from its under side upwardly and a cylindrical hole extending from the mortise to the top of the key, the cylindrical end of the balance rail pin being inserted in the lower portion of the hole and having a snug fit therein, a portion of the balance rail pin in the mortise having a snug fit therein to prevent side rocking of the key, a screw threaded in the upper portion of the said hole from the top of the key and forming with the upper end of the balance rail pin a fulcrum for the key located at about the center of the key between the top and the bottom.

12. In a piano as claimed in claim 11, a resilient punching located in the said hole between the upper end of the balance rail pin and the lower end of the said screw.

13. In a piano having a key bed H, a key frame l2 having a rear [4 and a front portion [5 connected by strips, the back portion of the key frame being secured to the key bed, the forward portion of the strips having a weakened section forming a hinge, there being a perforation 23 through certain of the strips adjacent their forward end, a screw 24 through each perforation, means 5| to attach each screw to the key bed II and a structure having a tubular escutcheon for each screw, the escutcheon 4i] resting on top of the screw whereby the adjustment of the forward portion of strips of the key frame adjusts a forward section of such key frame.

14. In a piano having a key bed, a key frame structure supported thereon, the front portion having a weakened section forming a hinge, the front portion of the key frame having an upper bore counter-sunk at the bottom and thereby forming counter-sink shoulders, a second bore in alignment therewith, a screw extending through the second bore and having a head bearing on the counter-sink shoulders, a cylindrical portion extending through the second bore having a threaded end with means engaging the threaded end and the key bed, a tubular escutcheon in the first bore bearing on the head of the screw, whereby on threading the screw downwardly the head bears on the counter-sink shoulders and moves the front half towards the key bed and on threading the screw outwardly the head engages the escutcheon and raises the front portion of the key frame above the key bed.

15. In a piano having a key bed, a key frame having a rear section secured to the key bed and a front section having weakened portions forming a hinge, a front rail 21 on the key frame and having a counter-sink bore 22 with countersink shoulders 22', the front portion of the key frame having a perforation 23, a screw 24 having a head engaging the counter-sink shoulders, the screw extending through the perforation, means connecting the threaded end of the screw with the key bed, an escutcheon 40 in the counter-sink bore 22 bearing on the head of'the screw whereby when the screw is threaded downwardly the head of the screw engaging the shoulders 22 adjusts the front half of the key frame towards the key bed and when the screw is threaded upwardly, the head engages the escutcheon and forces the front portion of the key frame upwardly away from the key bed.

16. In a piano as claimed in claim 15, the means for connecting the screw and the key bed comprising a key bed rail 5|, the key bed having longitudinal slots 52, screws 53 through the slots engaging the key bed rail 5|, the said screws 53 being removable whereby after disconnecting the rear portion of the key frame from the key bed, the key frame with the key bed rail 5| may be removed from the key bed.

17. In a piano having a key bed with longitudinal slots, 2. key bed rail extending longitudinally at the front of the key bed, a screw through each slot removably connecting the key bed rail to the key bed, a key frame having its rear portion removably attached to the key bed, having a front portion with a hinged connection to the rear portion, and interconnecting means between the front portion of the key frame and the key bed rail toadjust the spacing of the front portion of the key bed frame and the key bed, the key frame and the key bed rail being removable as a unit on disconnecting the said screws and the means attaching the rear portion of the key frame to the key bed.

18. In a piano as claimed in claim 17, the interconnecting means between the front portion of the key frame and the key bed rail comprising the front portion of the key frame having a structure with an upper bore having counter-sunk shoulders, a second bore in alignment therewith, a screw having a head engaging the shoulders and extending through the second bore and threaded into the key bed rail, and an adjustable tubular escutcheon in the first bore bearing on the head of the screw, whereby when the screw is threaded downwardly the head engages the shoulders and draws the front portion of the key frame towards the key bed and when the screw is threaded outwardly the head of the screw engages the escutcheon and thrusts the front portion of the key frame upwardly.

19. In a piano, the combination of a key bed,

a key frame secured to the bed, a balance rail on the key frame, a key fulcrumed on the balance rail, a front rail secured to the front portion of the key frame, said front portion of the key frame having a hinged section forward of the balance rail, and means to regulate the height of the said front portion and front rail relative to the key bed, the means to regulate the height of said front portion and front rail above the key bed comprising the front rail and the forward portion of the key frame having a counter-sink bore 22, a screw 24 having its head engaging the counter-sink and threaded into the key bed, and a tubular escutcheon 40 threaded into the bore and engaging the head of the screw.

20. In a piano, the combination of a key bed having a key bed rail on its front end removably attached to said bed, a key frame secured to the key bed rail, a balance rail on the key frame having a key fulcrumed thereon, a front rail on the forward portion of the key frame, said key frame having a section forming a hinge, and means for adjustably attaching the portion of the key frame forward of said hinge to the key bed rail, the means for attaching the front portion of the key frame and front rail to the said key bed rail comprising the front rail 2| and forward portion of the key frame having a counter-sink bore 22, a screw 24 in said bore having a head engaging the counter-sink and threaded into the said rail, and a tubular escutcheon 40 in the said bore of the front rail engaging the head of the said screw.

21. In a piano as claimed in claim 20, the key bed having a slot 52 formed in the key bed transverse to the key, a screw 53 extending upwardly through the said slot and threaded into the said rail, and a spring washer 54 between the head of said latter screw and the bottom of the key bed.

FRANK L. GEORGE.

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