US1228223A - Electromechanical action for musical instruments. - Google Patents

Description

F. B. LITTLE.

ELECTROMECHANICAL- ACTION FOR MUSICAL INSTRUMENTS. APPLI( IATION FILED FEB- 25, 1916.

1,228,223. Patented May 29, 1917.

Specification of Letters Patent,

Patented May 29, 1917.

Application filed February 25, 1916. Serial No. 80,328.

To all whom it may aoncem:

Be it known that I, FREDERICK B. Lrrnn, citizen of the United States, residing at Chicago, in the county of Cook and State of llinois, have invented a certain new and useful Improvement in Actions for Musical Instruments, of which the following is a full, clear, concise, and ex- I act description, reference accompan g drawings, this specifi dz t tion. 1

My invention relates to musical instruments of the percussion type and has for its object the construction of an improved electro-magnetic action whereby the sound producing elements of the instrument ma be impinged upon by hammers with blows of 'table force and in such manner that the hammers will not dampen the vibrations they set up in the sound producing elements. practising my invention I employ an electro-magnet for each action, the armature of the magnet carrying a hammer and also a switch actuating element for opening the circuit of the magnet when the hammer has been moved a predetermined distance toward the sound producing element it is to strike being bad to the forming a part of whereby the circuit of the magnet is opened erally on line 1 1 of Fig.

before the hammer completes its travel, momentum being relied upon to complete the hammer travel. A spring is employed against the force of which the magnet moves the hammer and against the force of which the hammer is moved by momentum when the circuit of the magnet is opened, the spring serving to restore the hammer after it has struck so that the hammer will not linger to dampen the vibrations set up in the vibrating element it has struck.

I will explain my invention fully by reference to the accompanying drawing showing the preferred embodiment thereof and in which Figure 1 is a view taken gen 2, the circuit arrangement of the magnet being also diagrammatically indicated in this gure; Fig. 2 is a front view of the structure shown in Fig. 1, a cap being shown in section at the upper end of the gure to reveal parts that it would hide; Fig. 3 is a perspective view of the switching and armature mechanism which I prefer to employ; Fig. 4 is an end elevation of the magnet structure shown in Figs. 1 and 2, the hammer being removed while the casing is shown in cross section on Electromechanical I my mventlon resonator 2 as at 4 to and between the lindrica'l casing 7 line 4 4 of Fig. 1; and Fig. 5 is a view taken at right angles to the part shown in Fig. 4. Like parts are indicated by similar characters of reference throughout the different figures.

The sound producing elements to which is adapted may be of any suitable nature, the sound producing element illustrated in the-drawing being in the form bar 1 located in front of a will be well understood by those familiar with. the art. A hammer 3 for striking the bar 1 is pivotally mounted ears 5 projecting from a bracket 6 that is attached to the cyby the screws 8. Nuts 9 are threaded upon the free ends of the hammer stem 10, the hammer ball 3 being secured between the nuts and being adjustable longitudinally of the stemflby reason thereof. The other end of the hammer stem projects from the armature 11, which is preferably circular, that carries the bar 12 by means of which the armature, as well as the hammer, is pivoted at 4. The bracket 6 carries an arm 13 that is insulated there from, a screw; 14 having threaded connection with this arm. A binding nut 15 is provided upon the screw for the purpose of engagin a circuit terminal therebetween and the %ar 13 whereby the screw is brought into electrical connection with such terminal. A terminal contact 16 is carried by the screw 14, this contact being compleof a vibrating mental to a terminal contact 17 carried upon the same. The arm 19, obviously, is insuand thenut engaging lated from the-arm 13 since the latter arm is insulated from the bracket 6. The arm 19, however, may be electrically connected with the bracket and the metallic parts upon the bracket. The magnet winding 21 of each action is included in a circuit traceable from the battery 22, the circuit closing instrument playing key 23, the contact screw 14 and the contact 16 carriedupon one end thereof, the contact 17 and the leaf spring 18 carrying this contact, thence to the winding 21 back to the battery. Whenever the switch 23 is' closed the winding 21 is energized and the armature 11' of the magnet is attracted to move the hammer to-- magnetically ward the sounding bar, the magnet being pulled until the insulating block 24 carried by the bight of the stirrup 25 engages the spring 18 that passes through the stirrup, it being observed that the stirrup moves with the armature as it is clamped between the armature and the bar 12. The engagement of the switch actuator 24 with the switch spring 18 occurs before the hammer 9 strikes the bar 1 and serves to break the circuit of the magnet at this time whereby the hammer completes its movement by momentum, it being thereby prevented from dampening the vibrations it sets up as it is instantly removed from engagement with the bar by the retractile spring- 26. This spring not only serves to retract the armature and the hammer but also serves to dampen the movement of the armature when the armature is magnetically attracted whereby the momentum imparted to the hammer is properly reduced. The magnet winding 21 is set into an iron cup 21 that is provided to make the magnet ironclad. The iron core 27 is attached to the end wall of this cup. The armature at the other end of the cup-shaped casing is opposed to the core and the rim'of the casing, the magnet structure illustrated being highly efficient as there are no wasteful air gaps to be threaded by magnetic flux. The

spool upon which the winding is disposed is preferably made of brass, the core 27 passin through the spool sleeve 28 while the en walls 29 of the spool define the winding space. A piece of felt 30 may be provided to prevent the armature from sticking and to prevent it from making noise when the hammer strikes.

Each switch 23 is individual to one magnet, it being understood that the different magnets are associated with different sounding bars that are arranged to produce the sounds of a musical scale. Taps 31 indicate the conductors that lead from the battery 22' to other switches 23 and taps 32 indicate conductors that lead from the other side of battery 22 to other magnet windings 21, though other circuit arrangement may be employed. The battery itself is included in a conductor that is common to all of the magnets, this conductor also including a switch 33 which may be thrown into one position when all of the magnets are to be excluded from circuit, termediate position when the normal battery 22 is to be included in circuit; and which may have a third position when the which may have an 1nextra battery 34 is to be included in series with the battery 22 to increase the voltage and cause the stronger operation of the hammer, the switch 33 thus constituting a modulating switch as well as a circuit opening and closing switch.

The insulating block 24 is desirably made of cushioning material and also extends outwardly so as to engage the arm acting as a rigid back stop when the armature is retracted, the co tact actuator of which the insulating block 24 forms a part being also employed as a means to limit the extent to which the armature may be retracted. The stirrup that supports the block is preferably resilient as well as the block 24 so that the armature is not violently arrested in its restorin .movement.

While I have herein shown and particularly described the preferred embodiment of my invention I do not wish to be limited to the precise details of construction shown as changes may readily be made without departing from the spirit of my invention, but having thus described my invention I claim as new and desire to secure by Letters Patent the following An electro-mechanical action for percussion musical instruments including an electro-magnet; a hammer carried by the armature of the magnet; a pair of contacts in the magnet circuit, one of these contacts having a spring support to enable it to be moved toward and from the other; a mounting for these contacts that is apart from the magnet armature; a contact actuator car-' ried by the armature and arranged to move said spring su port to exclude the magnet from circuit efore the magnetically attracted armature has completed its range of movement whereby the hammer will continue in movement of momentum; and a spring for restoring the armature and hammer and against the force of which spring the armature is magnetically attracted, the aforesaid mounting constituting a back stop engaged by said contact actuator when the armature 1S restored to limit the restoring movement of the armature efiected by the armature restoring spring.

In witness whereof, I ereunto subscribe I1I1i name this 17th day of February A.

FREDERICK B. LITTLE.

Witnesses:

G. L. Green, -ETTA L. W.

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