JPH0277093A - Actuator for automatic play piano - Google Patents

Abstract

PURPOSE:To increase the strength and to reduce the thickness by arraying and fixing electromagnetic plungers which correspond to respective keys zigzag in yoke constitution bodies and arranging the yoke constitution bodies in the array direction of the key in the space formed between a shelf plate 1 and the keys. CONSTITUTION:The actuator 30 which is formed flatly is arranged in the space 15 between the shelf plate 1 and keys 2 and between in and behind a stylus 23. This actuator 30 consists of a couple of upper and lower yoke constitution bodies 31A and 31B which extend long in the array direction of the keys 2 and the electromagnetic plungers 32 which are stored and arranged zigzag in the couple of upper and lower yoke constitution bodies 31A and 31B corresponding to the keys 2. Consequently, the strength of the shelf plate 1 is prevented from decreasing and the actuator is made compact.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an actuator for a self-playing piano that is unitized and can be built into a keyboard section.

(Prior art and its problems) In general, an actuator installed in a player piano to drive a key has an excitation coil and an actuator that is slidably inserted through the excitation coil with a small gap in the center thereof. A well-known electromagnetic plunger consisting of a movable iron core and a yoke that houses an excitation coil and forms a magnetic path is used, and is driven by an electrical signal obtained by reproducing information previously recorded on a tape, etc. This allows the key to operate as if it were pressed by hand. FIG. 1 shows a conventional mounting structure for this type of actuator, in which a mounting plate 3 that extends long along the direction in which keys 2 are arranged side by side (direction of arrow A) is installed at a predetermined location on the lower surface of a shelf board 1. arranged vertically. On this mounting plate 3, a plurality of electromagnetic plungers 5 corresponding to each key 2 are arranged in two stages, upper and lower, and movable and adjustable in the direction in which the keys 2 are arranged side by side. A total of four sliding grooves 4 formed in an H''' shape are formed vertically in parallel at predetermined intervals. The upper and lower ends of the yoke 6 are fitted with a set screw 7 and a square nut 8 which is slidably inserted into the sliding groove 4 and screwed onto the set screw 7. The yoke 6 is fixed in position.
An excitation coil 10 and a movable iron core 11 are housed in the internal space 9 of the movable iron core 11 . This movable iron core 11 projects above and below the yoke 6, and the projecting end that projects above is further provided with an insertion hole 12 formed of a square hole or the like drilled in the shelf board 1.
The push-up button 13 provided at the top of the key 2 is located close to and opposite to the lower surface of the rear end of the corresponding key 2. In addition, the upper electromagnetic plunger 5 and the lower electromagnetic plunger 5 are arranged in a staggered manner! ! It is shifted by 2 pitches.

However, in such a conventional actuator, when adjusting the mounting position of the electromagnetic plunger 5, not only does the electromagnetic plunger 5 move poorly and fine adjustment is difficult, but also the square nut 8 gets caught in the sliding groove 4, making it difficult to move. In bad situations, if you apply too much force and force the movement, the movable core 11 may move more than necessary and the movable core 11 may come into contact with the yoke 6 of another electromagnetic plunger 5 located diagonally above, or conversely, the yoke 6 may come into contact with another electromagnetic plunger 5. There was an inconvenience that the movable core 11 of the plunger 5 came into contact with the movable core 11, causing the movable core 11 to bend. In addition, since it is necessary to make the insertion hole 12 in the shelf board 1, the strength of the shelf board 1 may be significantly reduced, and for example, a pedal push-up bar (not shown), etc., which is disposed through the shelf board 1, etc. It may become necessary to change the mounting position of parts. Furthermore, since the mounting plate 3 and the electromagnetic plunger 5 are visible, the appearance of the piano is significantly degraded, and it is necessary to install the electromagnetic plunger 5 one by one to the mounting plate 3, so the installation and adjustment work is difficult. is troublesome and takes a long time, making manufacturing costs high. In addition, when installing the actuator to an existing product, it is necessary to fold down the piano body and drill the insertion hole 12, which requires extensive work and makes it inappropriate to assemble and install the actuator in a general household. Many inconveniences have been resolved.

In addition, it is known that an electromagnet is used instead of an electromagnetic plunger as a key drive actuator, and this is arranged in a space 15 provided between the shelf board 1 and the key 2. Compared to an electromagnetic plunger, a large driving force cannot be obtained, and an attempt to obtain a large driving force results in an increase in size, which not only increases power consumption but also causes problems such as interfering with the operation of the key 2 itself.

(Structure of the invention) This invention was made in view of the above points,
A plurality of electromagnetic plungers, each corresponding to security, are arranged and fixed in a staggered manner inside a yoke structure, and the yoke structure is placed in a space provided between a shelf board and a key along the direction in which the keys are arranged. The present invention provides an actuator for a player piano that solves the above-mentioned conventional disadvantages at once through an extremely simple arrangement, and can be made into a unit and compactly assembled.

(Example) Hereinafter, this invention will be described in detail based on an example shown in the drawings.

FIG. 2 is a sectional side view of a main part of a keyboard section equipped with an actuator according to the present invention, and FIG. 3 is an exploded perspective view of the same actuator. In these figures, a keyboard section 20 consisting of a front 21, a middle 22, a back 23, etc. is disposed on the top surface of the shelf 1, and above it a security guard 2 rotates the middle section. It is arranged to be able to swing freely in the vertical direction as a pivot point.

That is, the key 2 is swingably supported by a balance key pin 24 installed on the radiator 22 and inserted into a substantially fan-shaped through hole 25 formed in the middle part thereof.
By placing a known action mechanism (not shown) on the rear end portion 2A via the capstan 26, the front end portion 2B normally floats above the front reed 21, and the rear end portion 2A moves toward the rear of the reed. 23 with a felt 27 interposed therebetween. An oval key pin 28 on the upper surface of the front holder 21 has an upper end that is always engaged in a recess (not shown) formed on the lower surface of the front end 2B of the key 2, and that restricts and prevents the left and right rotation of the key 2. has been planted.

A flat actuator 3 is provided in a space 15 between the shelf board 1 and the key 2 and between the flow board 22 and the rear reed 23.
0 is placed. This actuator 30! A pair of upper and lower yoke structures 31A and 31B that extend long along the direction in which the two yoke structures 31A and 31B are arranged in parallel.
It is composed of a plurality of electromagnetic plungers 32 stored and arranged in a staggered manner in correspondence with the popular style 2 in A and 31B. The pair of upper and lower yoke components 31A and 31B are made of a magnetic material such as soft iron, so that each electromagnetic plunger 32
The upper surface of the lower yoke structure 31B, which is formed in the shape of a wire, provides a common magnetic path for the structure 31B.
An upper yoke component 31A formed in a plate shape is disposed so as to cover the opening, and is fixed with a set screw 33.

In the yoke structure 31B, a mounting portion 34 integrally formed by bending the upper end of the rear wall backward is fixed to the front end of the upper surface of the rear reed 23 together with the upper yoke structure 31A.
The front end side is fixedly held by a shield case 36 that shields the printed circuit board 35, so that the information on the shelf board 1 is arranged at a predetermined interval. The rear end of the printed circuit board 35 is fixed to the lower surface of the front end of the yoke structure 31B via an insulating paper (not shown). The shield case 36 is formed of a single-walled perforated plate into a substantially ] shape,
On the upper surface of the front end of the upper yoke component 31A,
The lower surfaces are placed and fixed on the upper surfaces of the shelf boards 1, respectively.

A plurality of insertion holes 37 and 38 are bored in the bottom surfaces of the upper yoke structure 31A and the lower yoke structure 31B in a staggered manner, corresponding to each electromagnetic plunger 32, respectively. Each electromagnetic plunger 32 is formed in a cylindrical shape,
A bobbin 39 that integrally has flanges at its upper and lower ends, an excitation coil 40 wound around the outer peripheral surface of the bobbin 39, and a bobbin 3
9, a pair of upper and lower yokes 41 and 42, and a shaft 43 that is fitted and fixed in the inner hole of the lower yoke 42. The flanges are fixed to the lower surface of the upper yoke structure 31A and the inner bottom surface of the lower yoke structure 31B with double-sided tape 44, respectively.

The lead wire 45 of the excitation coil 40 is connected to the upper yoke structure 3.
After passing through a lead wire insertion hole (not shown) drilled in the lead wire 1A and leading out to the outside, the lead wire is led into the shield case 36 and connected to the terminal portion of the printed circuit board 35. The upper yoke 41 is formed into a substantially cylindrical shape and is fitted and fixed to the upper end side opening of the bobbin 39, and the upper end portion is connected to the upper yoke structure 31.
It is fitted into the insertion hole 37 of A. Further, the lower end of the yoke 41 is formed into a truncated conical shape, and the upper surface thereof is formed with a recess 46 for accommodating the raised button 13 screwed onto the upper end of the shaft 43.

On the other hand, the lower yoke 42 is formed into a cylindrical shape, and its upper end is slidably inserted into the inner hole of the bobbin 39 through the insertion hole 38 bored in the lower yoke component 31B. A collar 47 is integrally fixed. And yoke 42
The upper end opening forms a tapered hole 48 that can be fitted into the lower end of the upper yoke 41 . The shaft 4
3 is a rod-shaped body made of a non-magnetic material, the lower end of which is fitted and fixed into the inner hole of the lower yoke 42, and the upper end of which is slidably passed through the inner hole of the upper yoke 41 to form the upper yoke. It protrudes above the structure 31A. Therefore, the lower yoke 42, collar 47, and shaft 43 are integrally coupled to form a movable member that is attracted upward and operates when a signal current is supplied to the excitation coil 40, as will be described later. A guard member 50 such as felt is provided on the upper surface of the collar 47.
The flange 47 is usually placed on a guard member 51 formed in a band shape from felt or the like on the upper surface of the shelf board 1.

A heat vibrator 52 is roughly housed inside the lower yoke structure 31B. This heat vibe 52 is for diffusing the heat of the excitation coil 40 in the direction in which the keys 2 are arranged side by side, and extends in the longitudinal direction of the yoke structure 31B.
A resin material 53 with high thermal conductivity is filled between the heat vibrator 52 and each electromagnetic plunger 32. As the resin material 53, epoxy resin mixed with metal powder, filler, etc. is used.

In FIG. 3, reference numeral 54 indicates a guide bushing that is fitted and fixed into the inner hole of the yoke 41, 55 and 56 indicate wood screws and spacers for fixing the upper and lower pair of yoke components 31A and 31B, and 5
7 is a side cap that closes the side opening of the yoke structure 31B.

In the actuator 30 having such a configuration,
The excitation coil 4 of the electromagnetic plunger 32 corresponding to the key 2 consisting of
When a signal current is supplied to 0, the pair of upper and lower yokes 41.4
As the lower yoke 42 is attracted and raised by the action of the magnetic flux generated in the magnetic gap between the two, the shaft 43 rises together with the lower yoke 42, and the lower surface of the rear end 2A of the key 2 protrudes upward from the button 13.
thrusts up. Therefore, the key 2 is driven as if it were pressed by hand. And excitation coil 4
When the signal current to 0 disappears, the shaft 43 and the lower yoke 42 fall due to their own weight and return to the initial position shown in FIG. 2 due to demagnetization, and the key 2 also returns accordingly.

Thus, since the actuator 30 is disposed between the shelf board 1 and the key 2, there is no need to process the shelf board 1 at all, and a decrease in the strength of the shelf board 1 can be prevented. In addition, since a plurality of electromagnetic plungers 32 corresponding to security 2 are commonly housed in the upper and lower pair of yoke components 31A, 31B and are made into a unit, it can be assembled compactly and is easy to attach and adjust to the keyboard section. Easy to work with.

Furthermore, since the actuator 30 is not visible from the outside of the piano body, deterioration of the appearance of the piano itself can be prevented.

Furthermore, a pair of yoke components 31A.

31B provides a common magnetic path for each electromagnetic plunger 32, so it reduces magnetic resistance, and at the same time radiates heat generated in the electromagnetic plunger 32 from its entire length together with the heat vibe 52. Make temperature distribution uniform. Therefore, the driving force of the electromagnetic plungers 32, which are frequently used, does not decrease due to the influence of heat, and the driving force of each plunger 32 can be kept constant.

FIG. 4 is a side sectional view showing a modified example of the above embodiment, which differs from the above embodiment in that the heat vibrator is removed, and a yoke 42, a shaft 43, etc. are provided between the up button 13 and the yoke 41. The point is that a well-known coil spring 80 is interposed to improve the standing up of the movable member. Since the other configurations are similar to those of the above embodiment, the same reference numerals are given and the explanation thereof will be omitted. In addition, 81 in the figure is the above-mentioned insulating paper. It is obvious that the same effects as in the above embodiment can be obtained also in such a configuration.

FIG. 5 is a partially cutaway side view of a keyboard section showing another embodiment of the present invention, and the same components as those in the above embodiment shown in FIGS. 2 and 3 are designated by the same reference numerals. , and its explanation will be omitted. In this embodiment, the actuator 30 is arranged in a space 60 between the shelf board 1 and the key 2 and between the front part 21 and the second part 22, and the upper end of the shaft 43 of each electromagnetic plunger 32 is connected to the front end of the key 2. 2B.

For this reason, the shaft 43 is inserted from above the key 2 into the insertion passage 61 bored in the front end 2B of the key 2 via the guide vibro 2 so as to be vertically movable, and its upper end is secured by a nut 63 and a rotation stopper 64. It is locked onto the upper surface of the key 2 to prevent it from coming off downward. On the other hand, the lower end of the shaft 43 protruding downward from the key 2 is fitted and fixed into the inner hole of the upper yoke 42 of the pair of yokes 41 and 42 constituting the electromagnetic plunger 32, and It is slidably inserted into the inner hole. In this case, the -pair of yokes 41 and 42 are arranged in a vertical relationship opposite to that of the above embodiment,
A lower end portion of the yoke 41 is fitted and fixed into the insertion hole 38 of the lower yoke component 31B. On the other hand, the yoke 42 is fixed to the lower surface of an armature 65 that is not placed on the upper surface of the yoke component 31A, and is fixed to the insertion hole 37 of the yoke component 31A.
It is inserted into the bobbin 39 to form a magnetic gap with the yoke 41. On the upper surface of the armature 65, a punching 66 formed into an annular shape made of leather, felt, etc. is mounted and fitted onto the shaft 43. The lower end of the shaft 43 corresponding to the key 2 disposed on the keyboard reed center lever 67 passes through the yoke 41 and is inserted into a through hole 68 formed in the keyboard ejector 67. Note that 70 is a guide bush through which the lower end of the shaft 43 is slidably inserted.

In the actuator 30 having such a configuration,
The excitation coil 4 of the electromagnetic plunger 32 corresponding to the key 2 consisting of
When a signal current is supplied to 0, the yoke 42 and the shaft 43
, the armature 65, etc. are attracted downward by the magnetic flux action generated in the magnetic gap between the pair of yokes 41, 42, and the key 2 is moved downward by the descent of the shaft 43.
is driven as if the keys were pressed by hand. Then, when the excitation coil 40 is demagnetized, the key 2 is rotated back to its original initial position due to the load of the action mechanism, and the movable members such as the shaft 43 are pulled up. therefore,
It is clear that even in such a configuration, the key 2 can be driven smoothly and the same effects as in the above embodiment can be obtained.

In this case, since the upper end of the shaft 43 is engaged with the key 2 by a nut 63 or the like, the key 2 and the shaft 43 can be operated integrally, and the key 2 and the actuator 30 can be connected by rotating the nut 630. Since the spacing between the keys 2 and 3 can be adjusted, variations in the driving force of the electromagnetic plunger 32 for each key 2 can be easily adjusted from the top of the key 2 even after the actuator 30 is assembled. Furthermore, since the actuator 30 pulls in the front end 2B of the key 2, the key 2 will not come out of the balance key bin 25 unlike the push-up type embodiment shown in FIGS. 2 and 3.

In the embodiment shown in FIG. 5, a case has been described in which the actuator 30 is arranged on the middle side 67 of the keyboard section, but the present invention is not limited to this, and the embodiment shown in FIGS. Of course, it is also possible to fix the keyboard to the ryukyu 22 or the front of the reed 21 and remove the keyboard release lever 67, similarly to the above.

(Operations and Effects of the Invention) As explained above, in the actuator for a player piano according to the present invention, a long yoke structure is arranged in the space provided between the shelf board and the keys along the direction in which the keys are arranged side by side. However, since multiple electromagnetic plungers for security purposes are housed in a staggered manner inside this yoke structure, it can be made thin and compact, and can be mounted in a large area under a shelf like in the past. There is no need to secure space, and since it is not visible from the outside, it does not spoil the external beauty of the piano. Furthermore, there is no need for any shelf board processing, and not only is strength maintained well, but installation and adjustment work is easy. In addition, since the yoke structure provides a common magnetic path for each electromagnetic plunger, it reduces magnetic resistance and has a large heat dissipation effect, so it can be used in practical applications such as preventing a drop in the driving force of the electromagnetic plunger. The effect is very large.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a main part showing the mounting structure of an actuator in a conventional player piano, FIG. 2 is a side sectional view of a main part showing an embodiment of a keyboard section equipped with an actuator according to the present invention, and FIG. is an exploded perspective view of the same actuator, No. 4
The figure shows another embodiment of the invention. Side sectional view of the panel,
FIG. 6 is a partially cutaway side view of a keyboard section showing still another embodiment of the present invention. 1...Shelf board, 2...Key, 15...Space, 30...Actuator , 31A, 31
B... Yoke structure, 32... Electromagnetic plunger, 39... 弗... Bobbin, 40... Exciting coil, 41, 42・ ・ !・ ・ ・York, 43...
......Shaft, 52...Heat vibe, 60...
・・・・Space. Patent applicant Kiyoshi Kuwai, agent of Nippon Gakki Manufacturing Co., Ltd. - Procedural amendment (voluntary) September 25, 1988 2, Title of invention Actuator for player piano 3, relationship to the amended person's case Patent Applicant Address: 10-1 Nakazawa-cho, Hamamatsu City, Shizuoka Prefecture Name: Nippon Musical Instruments Manufacturing Co., Ltd. Representative: Kawa
Hiroshi Kami 4, Agent 〒153 5, I have submitted a request for examination of the application at the same time as the claims section of the specification subject to amendment. (1) Amend the claims as shown in the attached sheet. (2) The description from page 3, line 16 to the last line of page 5 of the specification is deleted and the following sentence is added. ``A specific example of the structure of such a conventional electromagnetic plunger is disclosed in Japanese Patent Publication No. 48-33689. In this electromagnetic plunger, the upper end of the fixed yoke is convex, and the felt disk 22 is separated from the coil 35 by a large distance.By the way, in general, in pianos, the distance between the shelf board and the keys is extremely small (15 mm in a typical example), and actuators for player pianos can quickly drive keys that are quite heavy. Therefore, an actuator for a player piano must be made thin without reducing the number of windings. However, generally speaking, making the actuator thinner reduces the number of windings, which reduces the key driving ability. Therefore, an object of the present invention is to provide an actuator for a player piano that is strong and thin. It was made by
The gist is an actuator for a player piano that has an electromagnetic plunger that is disposed between a shelf board and the opposite end of the key pressing position with respect to a fulcrum, and is supported by the shelf board via a yoke structure. The electromagnetic plunger includes an excitation coil supported by the yoke structure, a fixed yoke connected to the excitation coil and having a concave portion on the key side and a convex portion on the shelf side, and a fixed yoke that slides on the fixed yoke. a shaft that can freely pass through and protrude toward the key; a movable yoke that is fixed to the shelf side end of the shaft and has a recess that is formed by a surface that is substantially parallel to the protrusion of the fixed yoke; and a raised button fixed to the key-side end of the shaft and retractable into the recess when the movable yoke moves toward the opposite side of the fixed yoke. (3) The description from page 16, last line to page 17, line 15 of the specification is deleted and the following sentence is added. rAs explained above, according to the present invention, the key side of the fixed yoke is made into a recess, so when the movable yoke is separated from the fixed yoke, the push-up button can be stored in the key-side recess of the fixed yoke. can. Therefore, the excitation coil can be made thinner by a distance corresponding to the thickness of the raised button without reducing the number of turns of the excitation coil. Furthermore, in the actuator for a player piano according to the present invention, since the fixed plunger has a convex shape on the shelf side, it is possible to reduce the distance between the fixed plunger and the concave portion of the movable yoke while ensuring sufficient wall thickness. This makes it possible to further reduce the thickness of the actuator.゛sat, 2, . ``2. Actuator for a self-playing piano as claimed in the claims.

Claims (1)

[Claims] A plurality of electromagnetic plungers are provided in spaces provided between the keys and the shelf board to correspond to each key, and a yoke structure for storing and fixing the plurality of electromagnetic plungers, The electromagnetic plungers each have an excitation coil, a movable member, a yoke, etc., and are arranged in a staggered manner, and the yoke structure extends long along the direction in which the keys are arranged side by side, and provides a common magnetic path for each electromagnetic plunger. An actuator for a self-playing piano characterized by forming an actuator.