US3688634A

US3688634A - Keyframe side pin guide for piano and like musical instruments

Info

Publication number: US3688634A
Application number: US143425A
Authority: US
Inventors: Eiji Harada
Original assignee: Individual
Current assignee: Individual
Priority date: 1970-08-28
Filing date: 1971-05-14
Publication date: 1972-09-05
Anticipated expiration: 1989-09-05

Abstract

There is described an improved keyframe side pin guide for pianos and the like musical instruments wherein means are provided for preventing warp curving of the front part or front rail of the keyframe and for holding the same constantly in closely contacting relationship with the key bed on which the keyframe is supported, the means comprising a pin projecting from the keyframe, a pin-receiving member having a verticallyextending slot therein, the pin being inserted in the slot, a guide piece slidable along the slot and resting on the pin, and a resilient member exerting a constant downward pressure on the guide piece, so that the pin is firmly pressed toward the key bed owing to the downward biasing force of the resilient member.

Description

[ 1 Sept. 5, 1972 [$4] I KEYFRAME SIDE PIN GUIDE FOR PIANO AND LIKE MUSICAL INSTRUMENTS [72] Inventor: Eiji llarada, 1522-1 Kobayashi, Shizrioka-ken, l-lamakita-shi, Japan 221 Filed: May 14,1971 21 Appl.No.: 143,425

[30] Foreign Application Priority Data Aug. 28, 1970 Japan ..45/85228 s2 U.S. c1 ...84/432 51 1111.01. ..G1o3/12 [58] FieldofSearch ..84/423, 432

[56] r v References Cited I UNITED STATES PATENTS 480,014 8/1892 Hawes .;..84/432 745,509 12/1903 Muller; ..84/432 3,363,499 1/1968 Matsumoto .;...84/432 Primary ExaminerStephen J. Tomsky Assistant Examiner-Lawrence R. Franklin Attorney-Curt M. Avery et al.

[57] ABSTRACT There is described an improved keyframe side pin guide for pianos and the like musical instruments wherein means are provided for preventing warp curving of the front part or front rail of the keyframe and for holding the same constantly in closely contacting relationship with the key bed on which the keyframe is supported, the means comprising a pin projecting from the keyframe, a pin-receiving member having a vertically-extending slot therein, the pin being inserted in the slot, a guide piece slidable along the slot-and resting on thepin, and a resilient member exerting a constant downward pressure on the guide piece, so that the pin is firmly pressed toward the key bed owing to the downward biasing force of the resilient member.

"9Claims,5DrawingFigures mimtb ir m I 3.688.634

sum 1 or 2 FIG. 7

R/OR ART KEYFRAME SIDE PIN GUIDE FOR PIANO AND LIKE MUSICAL INSTRUMENTS This invention relates topianos and like musical instruments and more particularly to improved keyframe the keyframe causes differences or irregularities in the touches of the individual keys and noises are produced when the keys are depressed by the player if there is a space or gap wider than 0.1 mm between the keyframe and key bed.

In order to prevent warp curving of the keyframe and to maintain the same in closely contacting relationship with the key bed, there has been proposed a keyframe side pin guidecomprising a pin projecting from the keyframe, a pin-receiving member having a vertical slot therein, the pin being inserted in the slot, a guide piece slidable along the slot and resting on the pin, and adjusting screw means threadedly attached to the pinreceiving member, the screw means being permitted of the up and down movement along the slot by being turned, the downward movement of the screw means guiding the guide piece downward along the slot, thereby pressing the pin of the keyframe toward the key bed and preventing upward curving of the front member of the keyframe.

The above prior keyframe side pin guide construction is effective to a certain degree in holding the keyframe firmly. Nevertheless, the prior construction using an adjusting screw has a drawback in that it requires elaborate adjustments from time to time to ensure that the keyframe is in correct position with respect to the key bed, and it is often found difficult to make fine adjustment of the gap between the keyframe and the key bed due to the fact that there is a limit to narrowing the pitch of the adjusting screw for such purposes.

It is therefore the primary object of the invention to provide an improved keyframe side pin guide which will eliminate the difficulties mentioned above.

It is another object of the invention to provide keyframe side pin guide which is capable of constantly maintaining the keyframe infinitesimally close to the key bed without requiring any subsequent adjustment.

It is a further object of the invention to provide a keyframe side pin guide incorporating a resilient means for pressing a guide piece against the side pin of the keyframe.

It is still another object of the invention to provide a combination of a leaf spring and a pressure transmitting member adapted to maintain the keyframe constantly in closely contacting relationship with the key bed.

According to one feature of the invention, there is provided a keyframe side pin guide for a piano or like musical instruments connecting a keyframe to a key block, the guide comprising a pin projecting from the keyframe, a pin-receiving member having a vertical slot therein, the pin being inserted in the slot, a guide piece slidable along the slot and resting on the pin, and resilient means exerting a constant downward pressure on the guide piece, so that the guide pin is pressed to the pin owing to the downward pressure of the resilient means.

The foregoing and other objects and additional advantages as well as features of the invention will be more fully understood from the ensuing description of the accompanying drawings, the latter serving for explanatory purposes only and are not intended to in any extent limit this invention and in which drawings:

FIG. 1 is a perspective view showing one example of the keyframe and key blocks of a grand concert piano;

FIG. 2 is a fragmentary perspective view on enlarged scale of the keyframe side pin guide of the known construction;

FIG. 3 is an elevational front view of the keyframe side pin guide shown in FIG. 2;

FIG. 4 is a view similar to FIG. 2 but showing a keyframe side pin guide embodying the invention; and

FIG. 5 is an elevational front view of the keyframe side pin guide shown in FIG. 4.

Referring to the accompanying drawings, FIG. 1 shows an example of a combination of the keyframe and key blocks each located at the side of the keyframe. The keyframe l is formed by assemblage of afront rail 6, a balance or intermediate rail lb, a back or rear rail la, and a plurality of transverse slats 10 connecting the rails. The keyframe l is freely movable horizontally in the longitudinal direction over a key bed (not shown) under the guidance of back rail guides 2. A keyframe side pin guide 5 is mounted by means of wood screws 8e onto an inner end face of each

key block

3 or 4 for engagement with outwardly extending side pins 7 which are partly embedded fixedly in the bass and treble ends of the front part or front rail 6 of the keyframe.

As shown in FIGS. 2 and 3, it has been the conventional practice to provide a side pin guide body 8 generally of a saddle shape. The guide body is provided with two wing-like side portions 8b joined by an upper cross piece or bridge 80, an adjusting screw 10 in screw thread engagement with a vertical tapped through hole formed in the bridge member, and a guide piece 9 slidably engaged in a vertical cutout slot 8a formed in the guide body 8 at a position below the bridge member 8c and between the inner sides of the flanged portions. The wing portions 8b are respectively provided with a horizontally elongated slot 8d for mounting the guide body 8 onto the

key block

3 or 4.

The adjusting screw 10 is inserted from the upper side of the bridge in such a manner that the lower tip of the screw rests'against the upper surface of the guide piece 9.

The

key blocks

3 and 4 located respectively at the bass and treble ends of the keyframe l are secured to the key bed (not shown). Each side pin guide assembly 5 is mounted on its respective key block by means of wood screws See, the screws being passed through the slots 8d formed in the guide body and screwed into the

key blocks

3 and 4 as shown in FIG. 2. The surface of the key block is recessed for receipt thereinto of the pin guide assembly 5 so that, when the side pin guide is mounted, its outer most part does not project outward beyond the inner end face of the key block. The key block is further forrned'with a groove or cutout 3a above the adjusting screw so that a screwdriver can be inserted from above to turn the adjusting screw.

With the above described prior keyframe side pin guide construction, the side pin may be closely held by the guide piece and the keyframe front rail may also be prevented from curving upward. However, in order to ensure that the keyframe be held constantly in optimum position with respect to the key bed, the adjusting screw must be loosened or tightened from time to time by elaborately inserting a tip of a screwdriver through the narrow gap or space provided by the eutout groove and, therefore, the adjusting operation is sometimes rendered annoying and difficult.

The present invention contemplates to provide a new and improved keyframe side pin guide construction whereby the keyframe front rail may be prevented from beingcurved due to warping by means of a resilient means adapted to depress the guide piece firmly against the side pin, without requiring any additional or subsequent adjustment once the side pin is held in position.

Referring to FIGS. 4 and 5, there is shown a keyframe side pin guide construction according to the present invention. The side pin guide of the invention comprises a pin guide body or pin-receiving member 1 l of generally symmetrical saddle shape and integral structure having wing-shaped side portions 110 on opposite sides of a vertically extending cutout slot 11a. The wing portions 11 are bridged by a crossing or bridging member 11d and formed with horizontally extending elongated slots 11b. These elongated slots 11b are adapted to receive therethrough wood screws 13 for fixedly mounting the guide body or pin-receiving member 11 onto the key block 3. A guide piece 12 is fitted in the cutout slot 1 la so as to be vertically slidable therein.

Formed vertically through 'the bridge or crossing member 11d is a through hole lle for receiving therethrough a lower or larger diameter portion 140 of a pressure transmitting rod member 14. The rod member 14 is provided with a smaller diameter portion 14b at its upper end. The rod member 14 is inserted from above into the vertical through hole lle of the bridge member 1 1d with its lower tip end rested against the upper surface of the guide piece 12. The guide piece 12 is placed on the pin 7 so as to press the pin 7 downward.

Disposed above the guide body 11 a resilient means which, in the example, is shown as an elongated leaf spring member 15 adapted to depress the guide piece 12 firmly against the side pin member 7 by way of the pressure transmitting rod member 14. One end of the leaf spring member 15 is fixedly secured to the key block 3 while the other end is rested against a stepped portion or shoulder 140 of the rod member 14, so that it exerts a downward biasing force on the rod member 14. The smaller diameter portion 14b of the rod member 14 is passed through a hole formed in the leaf spring member 15 adjacent to the free end thereof. As for a resilient means, the leaf spring member 15 is preferred to have such pressure as to be capable of exerting from above a depressing force of 3 to 5 kg/cm on the stepped portion or shoulder 14c of the pressure transmitting rod member 14.

It will be appreciated that, with the side pin guide construction of the invention described above, the side pin 7 embedded in each of the bass and treble ends of the keyframe may be constantly firmly held in position by means of cooperating action of the leaf spring 15 and guide piece 12 receiving a downward pressure therefrom through the pressure transmitting rod member 14. Accordingly, the keyframe front rail 6 is prevented from warp curving and the gap between the front rail 6 and the key bed may at all times be maintained narrower than 0.1 mm once the side pin is fitted into the side pin guide without such subsequent adjustments as heretofore been required in the prior art side pin guide construction.

It will be understood that a side pin guide of the same construction is mounted symmetrically onto each one of the key blocks located respectively at the bass and treble ends of the keyframe, although the foregoing description has been made in conjunction with only one side pin guide construction. a

While a specific embodiment of an improved side pin guide for piano keyframes has been disclosed in the foregoing description, it will be understood that various modifications and changes within the spirit of the invention may occur to those skilled in the art. For example, the pressure transmitting rod member maybe of a construction other than described hereinbefore and illustrated in FIG. 4 and 5 insofar as it is capable of transmitting the downward biasing force of the leaf spring from above to the guide piece urging the side pin of the keyframe in a downward direction. Therefore, it is intended that no limitations be placed on the invention except as defined by the scope of the appended claims.

What is claimed is:

l. A keyframe side pin guide for piano or like musical instruments connecting a keyframe to a key block, said guide comprising a pin projecting from said keyframe, a pin-receiving member having a vertical slot therein, said pin being inserted in said slot, a guide piece slidable along said slot and resting on said pin, and resilient means exerting a constant downward pressure on said guide piece, so that said guide pin is pressed to said pin owing to the downward pressure of said resilient means.

2. The guide as claimed in claim 1 wherein said resilient means is a leaf spring.

3. The guide as claimed in claim 1 wherein said pinreceiving member includes a pair of side portions and a bridge portion coupling said side portions, said portions defining said vertical slot therebetween, said pressure transmitting member being slidable through a through hole formed in said bridge portion.

4. The guide as claimed in claim 1 further comprising a pressure transmitting member interposed between said resilient means and guide piece, said pressure transmitting member transmitting said downward pressure of said resilient means to said guide piece.

5. The guide as claimed in claim 4 wherein said pinreceiving member has a through hole perforated therein, and said pressure transmitting member is inserted in said through hole so as to be slidable therethrough.

6. The guide as claimed in claim 4 wherein said pressure transmitting member has a larger diameter portion, a smaller diameter portion, and a stepped pressure on said guide piece, so that said guide pin is pressed to said pin owing to the downward pressure of said resilient 'means. a

8. The guides as claimed in claim 7' wherein said resilient means is a leaf spring.

9. The guides as claimed in claim 7 further comprising a pressure transmitting member interposed between said resilient means and guide piece, said pressure transmitting member transmitting said downward pressure of said resilient means to said guide piece.

$ 2353? 32 x212 OFFICE r-v, r \1 :2 QER Iii iKCA-LTE QQERFMGTAUBT Patent N 3, 88,63 Dated September 5, 1972 Iw nt fls) EIJI HARADA in the above-identified patem:

It is cert Eied that error 2133;; s

1 e y corrected as shown below;

and that said Letters Patent are n f In the heading to the printed specificat'ioh there should be included:

----Ass:tgn -2e: Nippon Gakki Sei'zo Kabushiki Kaisha Hamamatsu-shi, Japan Signed and sealed izhie 26th day of March 1972 (SEAL) Attest: I

A EDWARD M.FLETCHER JR. C MARSIiALL DANN Attesting Officer Commissionerof Patents 2 7 3 STE-LL35 iAiE T OFFICE @F QCQRLBCTEOX Patent No.- 3 688,63 4 Dated September 5, 1972 IWenT- M EIJ I HARADA It is certified that-error appears 1;. the above-ider ltified patent and that said Letters Patent are hereby corrected as shown. below:

In the heading to the; printed specificatioh there should be included:

-Assignee: Nippon Gakki Seizo Kabushiki Kaisha Hamamatsu-shi, Japan Signed and sealed this 26th day of March 197% (SEAL) Attest: I

EDWARD M.FLETCHER,JR. C. MARSIPXLL DANN Attesting Officer Commissloner of Patents

Claims

1. A keyframe side pin guide for piano or like musical instruments connecting a keyframe to a key block, said guide comprising a pin projecting from said keyframe, a pin-receiving member having a vertical slot therein, said pin being inserted in said slot, a guide piece slidable along said slot and resting on said pin, and resilient means exerting a constant downward pressure on said guide piece, so that said guide pin is pressed to said pin owing to the downward pressure of said resilient means.

3. The guide as claimed in claim 1 wherein said pin-receiving member includes a pair of side portions and a bridge portion coupling said side portions, said portions defining said vertical slot therebetween, said pressure transmitting member being slidable through a through hole formed in said bridge portion.

5. The guide as claimed in claim 4 wherein said pin-receiving member has a through hole perforated therein, and said pressure transmitting member is inserted in said through hole so as to be slidable therethrough.

6. The guide as claimed in claim 4 wherein said pressure transmitting member has a larger diameter portion, a smaller diameter portion, and a stepped shoulder portion at which said larger and smaller diameter portions join, said resilient means being mounted on said stepped shoulder portion.

7. A pair of keyframe side pin guides for piano or like musical instruments connecting a keyframe to a pair of key blocks each disposed at the sides of said keyframe, each of said guides comprising a pin projecting from said keyframe, a pin-receiving member having a vertical slot therein, said pin being inserted in said slot, a guide piece slidable along said slot and resting on said pin, and resilient means exerting a constant downward pressure on said guide piece, so that said guide pin is pressed to said pin owing to the downward pressure of said resilient means.

8. The guides as claimed in claim 7 wherein said resilient means is a leaf spring.