US576342A - George howlett davis - Google Patents

Description

(No Model.)

G. H. DAVIS. ELEGTRIGALLY OPERATED MUSIGALINSTRUMENT. No. 576,842. Patented Feb. 2, 1897. f; x 70 T i f 1" I WHTNEiiiF:

. ATTORNEY INVENTOR UNITED STATES PATENT OFFICE.

GEORGE HOWLETT, DAVIS, on NEW YORK, N. Y

ELECTRlCALLY-OPERATED M US lCAL INSTRUM ENT.

SPECIFICATION forming part of Letters Patent No. 576,342, dated February 2, 1897.

' Application filed March 25, 1896.

1'0 all whom it may concern Be it known that I, GEORGE HOWLETT DA- vIs, a citizen of the United States, residing at New York, in the county of New York and State of New York,have invented certain new, useful, and valuable Improvements in Electrically- Operated Musical Instruments, of which the following is a full, clear, and exact description.

This invention relates to electrically-operated musical instruments, and has for its object to provide improved means for effecting economy in the electrical energy necessary to actuate the sounding mechanism; and to this end it consists in the features and in the construction, combination, or arrangement of parts hereinafter described, and definitely pointed out in the claims fol owing the desoription.

In the described class of musical instruments, such as electrically-operated pianos, for example, considerable force is required to efiect the initial movement of the arms.- ture,'but' only the slightest force is required to hold the armature against the magnetheads after it has once reached that position, it only being necessary in an electric piano to hold the damper oil? the string during the continuation of the note or energization of the magnet, and this diminution of force is even more permissible when one takes into consideration that after the initial movement the magnet and its armature are in close proximity, and that the attraction between any magnet and its armature varies. inversely as the square of their distance, and for these two reasons the electromagnets need not,after the initial movement has been made, be energ'ized up to within one-tenth of the degree required to make the blow, and it is to effect this great reduction of energization or saturation of the magnets at the proper time and to effect a corresponding saving of the electric current that has led to the present invention.

As the great amount of current required to operate electric pianos has rendered their use objectionable, especially when it is necessary to employ a storage or other form of battery, their use will now become more general, as this invention obviates the great disadvantage referred to. I accomplish these ends by Serial No. 584,762. (No rriodel the means illustrated in the accompanying drawings, forming a part of this sneci fication, and in which- Figure l is a transverse sectional view of one form of my improvements shown in connection with a piano-key. Fig. 2 is a rear view taken through the line X X of, Fig. 1. Fig. 3 is a transverse sectional view of a modifled form of my improvements. Fig. 4 is a similar view of still another form of my improvements, and Fig. 5 is an enlarged detailed view of the knife-switch employed throughout the several views.

Proceeding with a detailed description 0 the several parts I first take up those shown in Fig. 1, similar characters of reference being employed to indicate the same part when it occurs in one or more views.

Secured to the under side of the key-bed of the piano is a supporting rail or block 1, and to this is secured the angle-iron 2, supporting the magnets 3, composed of the spools 4 5, and to which angle-iron is also secured a series of cleats 6, held in position by the screws 7 and pivot-ally supporting the armature 8, terminating in the wooden extension 9. At the extreme end of said extension is a strikerrod 8', which is connected to the key extension 10 of the piano-key 11, the said armature 8 normally resting upon the adj ustmentscrew 12, set in the angle-iron. Arranged above and in line with extension 9 is the knife-switch 14, having blades 15 16, which are secured to either side of an insulatingstrip 17, projecting from the wood rail 18, said blades 15 16 normally pressing together and forming a metallic contact near their lower ends, as clearly shown in Figs. 2 and 5, and through which point the electric current passes. When the said blades 15 16 are separated by the npward movement-of-the extension 9, the current, now having no other path, is forced to pass through the resistance 19, as well as. through the spools 4 5 of the magnets 3, which latters energization remains unbroken throughout the cutting-in of the resistance 19. The effect of the cutting in of said resistance is to diminish the amount of 100 current passing through said magnets 3 the moment it has actuated its armature 8 and causes its extension 9 to separate the said blades 15 16 and cut in the resistance 19, and

because the armature has performed its heaviest work in making its initial movement, sufficient resistance can be thrown in to allow but the slightest amount of current to pass through said magnet and resistance.

\Vhen the circuit is broken,the armature S.

and extension 5) drop down into their normal positions and but a very small spark occurs at the point where the circuit is broken, owing to the greatly-reduced current.

In the modification shown in Fig. 3 I have substituted for the dead resistance 19 (shown in Fig. I) an extra spool or resistance magnet 20, which is supported in a U-shaped angle-iron 21, together with the spools 22 23, forming magnets 24, the cleats (l, armature 8,

extension 9, and knife-switch 14, which latter is practically of the same construction as shown in Fig. 1, except that the said knifeswitch is supported in cleats 23, as shown,

said switch serving to cut in the resistancemagnet 20 whenever the blades 15 '16-are open.

in practically the same way as the dead resistance 19 is cut in in Fig. 1. This latter arran gement (shown in Fig. 3) is an advantage,

as the resistance-magnet assists the magnet 24 in sustaining the armature 8.

In the modification shown in Fig. 4 I show two sets of magnets cooperating with a constantly-revolvin g f riction-drum 24', it having been found that a hard blow can be struck with greater economy of power or current by throwing various forms of shoes against such a drum by electromagnets than to make the blow by the use of electromagnets alone, and when it is desired to do this-I prefer to suspend the reciprocating rod 25 in .f ront of the upper and lower magnets 26 27, the former magnet producing an initial movement, as will be shown by tracing up the circuits, and the latter magnet 27 being cut in through the action of the knife-switch 14, the blades 15 16 of which are separated in this case by a pin 28,.projecting from the upper end of the said reciprocating rod 25, said pin being made of some form of insulating material, the effect of the energization of said magnet 26 bein to draw the said reciprocating rod 25 forward and cause its shoe 29 to come into frictional contact with the revolving drum 24, by which the rod is thrown upward with considerable force, during which movement the resistancemagnet 27 is cut in through the knife-switch 14, acted upon by the pin 28, as before described.

In the drawings 1 nave shown the circuit making and breaking mechanism in a conventional manner, but in practice the circuit will be closed and broken automatically by the usual perforated music-sheet mechanism in a well-known manner.

In order to calculate the actual percentage of saving the use of my improvements effects, let us consider theconstruction shown in Fig. 3, and suppose the resistance of the two-spool magnets to be three ohm's and of the resistance-magnet thirty-seven ohms, and that the electromotive force of the battery is four volts, then, in accordance with well-eetab lished laws, which tell us that the current is equal to the electromotive force, divided by the resistance (or (3:12), have a momentary current of one ampere passing through the two-spool magnet during we find that, we

7 the initial movement of the armature, which,

as heretofore explained, instantly cuts in the resistance-magnet 0t thirty-sevenohms resistance, which, added-to that of the two-spool magnet, makes a total of forty ohms resistance, which, by again. applying the above rule, we find now allows a current of but onetenth ampere to pass, thus electing a positive saving of nine-tenths ampere during the remainder of the time the circuit remains closed, and in fact the two-spool magnet isin circuit for so short a. time (estimated to be not over one one-hundredth part of a second) that the current can be calculated as one-tenth ampere constant, and as the above flguresare taken from magnets "11 actual use operatin a piano-key, the deductions may beaccepte as being accurate.

. I claim-- .7

1. In an electrically-operated musical instrument, the combination with a key, ofan armature connected to said key, an electro magnet for actuating said armature, a source of electrical energy for energizing said magnet, a resistance, and means operated by the armature when the latter is attracted by its magnet for cutting the resistance into the circuit to reduce the current passingthrough the magnet, substantially as described.

2. In an electrically-operated musical in strument, the combination with a key, of an armature connected to said key, an electromagnet arranged in a normally open circuit foractuating said armature, means for closigg the circuit, a resistance, and means opera by-the armature when the latter is attracted 7 described.

4. In an electrically-operated musical instrument, the combination with a key, of a pivoted armature connected at its free end to said key, an electromagnet arranged in a normally open circuit for actuating. said arma ture, means for closing the circuit, a resistance arranged ina circuit in series with themagnet-coils, and connected at its terminals to the normally closed members of a knifeswitch operating to cut out said resistance, and a wedge carried by the armature operating-when the armature is attracted by its magnet to separate the members of the knife-' nected at its terminals to the normally closed members 15, 16 of a knife-switoh 14, said members being included in the magnet-circuit but insulated from each other, and means forclosing'said circuit, all constructed and arranged in the manner described, whereby when the circuit is closed the armature is attracted by its magnet to actuate the key, and the members 15, 16 are separated by the nonconducting extension 9, thus cutting the resistance into circuit and reducing the current passing through the magnet, for the purpose specified.

In testimony whereof I affix my signature in presence of two witnesses.

GEORGE HOWLETT DAVIS.

Images