US1720542A

US1720542A - Radio reproducing attachment for pianos

Info

Publication number: US1720542A
Application number: US199822A
Authority: US
Inventors: John M Coote; Clarence E Pryor
Original assignee: Individual
Current assignee: Individual
Priority date: 1927-06-18
Filing date: 1927-06-18
Publication date: 1929-07-09
Anticipated expiration: 1946-07-09

Description

July 9, 1929. J. M. cam-E ET A L l1,720,542

' RADIO RPRODUCING ATTACHMENT FOR PIANos Filed June 18, T927 y E 24 E.

. Y v W X bo lNvENToRS,

a Z6 @WIG ZY 24 26a l I9 I T5@ w '1 o A Patented July 9, 1929. i

UNI-TED srrATEsA PATENT OFFICE. y

JOHN M. coo'rE AND CLARENCE E. rRYoR, 'or ELIZABETH, NEW JERSEY.i

RADIO REPRODUCING v.A'JETACHJYI152NT FOR PIANOS.

Application med June 1s,

This invention relates to radio reproducing attachment for piano sounding boards 4 and the like. i

Pursuant to our invention, the electrical radio' reproducing deviceactuated by the radio receiving set is adjustably positioned relatively to the sounding board of a piano, usually at the region of engagement of the are reproduced effectively byfthe sounding board vibrating as a whole.

It is usually convenient inl upright and grand types of pianos to attach our attachment to the rear of the sounding board.

Further features and objects ofthe invenf tion will be more fully understood from the following detail description andthe accompanying drawings, in which Fig. 1 is an elevation of the rear of an upright .form of piano, showing. our radioreproducer attached thereto;

Fig. 2 is a sectional elevation on line 2- 2 of Fig. 1, on a greatly enlarged scale;

Fig. 3' is a sectional elevation on line 3 3 of Fig. l; i

Fig. 4 is a sectional elevation on line 4-4 of Fig. 3, on an enlarged scale; l

Fig. 5 is a detail sectional elevation of certain parts;

Fig. 6 is a detail view of a modification; and Fig. 7 is a detail view showing the assembly of our invention in a grand piano.

Referring to the drawings, the piano 1() may be of any form, and includes a suitable sounding board 11, associated with the usual treble bridge 12 disposed on the inner face of the sounding board, for locating the wires Corresponding to the keys of the piano; the key actuating and damping parts are of the usual or any approved type. Y

In the instance of an upright piano, as il- `1327. serial No. 199,822.,

tending. from the bottomvrail -14 to the top 55 rail 15. f

It Visconvenient to attach our radio reproducer 16 between-two central stanchions13, 13b, to locate the actuated element 17, see Figs. 2 and ,3, of our radio reproducing device 16 60 in substantially horizontal alignment with the intersectionr of the bridge 12 with the sounding board 11 between such'

Vcentral stanchions

13, 13b; f

Usually, the sounding board ofa piano is held to the bridge by a button `18 which is secured by a screw or a dowel pin.. Such button is preferably lof harder wood or other material than the sounding board.

An effective manner of assembly of our invention is had by removing the screw, then' removing the button, then boring a hole 19 at the location through the sounding` boa-rd and into the bridge, and then inserting a dowel p pin. 20 of maple or like material, which pin 75 20 tightly iits 'the bored hole. The pin 20 is glued fast in the bored hole. l The aperture 21 is bored through substantially the center of the pin 20, but not eX- teding entirely through the pin, thus leaving the solid bottomed portion 20. The but? Y e ton 18 is replaced and secured' by glue.

Any suitable `:t'orm of electrically actuated radio reproducing device may be employed, which comprises usually one or more voice coils 22, the windings of which are connected with the terminals of the plug ory of the last audio stage of the radio receiving set, and also usually comprising an armature 23 which is vibrated in correspondence to variatios of the electrical current passing through the windings of the voice coils. Such radio reproducing device usually includes also a permanent magnet and a core controlling the range of movement of the armature and the path of the electro-magnetic H ux created 4jointly by the permanent magnet and the variatlons` of the current passing through the voice coils 22.

We have shown the vibrated member 24 approximately three-thirty seconds of an inch outer diameter. The free end of the member 24 is soldered aspindicated at 24 within the bored opening \2.6. The inner end 26".of the rod 26 is threaded to be screwed into the bore of the plug 27. The

bore of the plug 27 does not extend through the bottom of the plug 27. The leather plug serves to preclude contact at any location. between the rod 26 and the pin 20. Generally speaking, the highest grades of leather give best results and we have obtained optimum results bythe use of oak tanned leather of the back of the hide.

As is indicated in Figs. 2 and 3, our radio reproducing attachment is conveniently secured in position by means of a supporting and adjusting bar 28 extending between the stanchions13" and 13" and adjustably secured thereto by means of the

screws

29, 30

, passing through suitable openings in the bar Our radio reproducing attachment is assembled and adjusted by means of the

screws

29, 30 and the member 24 and rod 26 integrally connected to one another at the set position, as above described, to locate the end 26" in firm engagement under pressure with the leather shielding 27. Such adjustment is made while the movable or actuatable parts of the radio reproducing device arequiescent and also to locate the armature to have free vibration under electro-magnetic actuation. Such relationship of the parts enables the screws 29, l30 to be further adjusted in their tapped'openings in the

braces

13, 13" if desired, or from time to time, loosened or tightened, to thereby correspondingly adust the bar 28 and therewith our radio repro ucing unit 16, including its actuated

members

24, 26, relative to the sounding board 11 and the bridge 12, for

attaining optimum reproduction and also for permitting a range of variation of' the emitted volume of the reproduced sounds.

Preferably, our radio reproducing unit 16 comprises a laminated core 31 which is secured The armature 23 is preferably anchored lat its iixed end 23"L to a rigid support, such as the bar 35, in turn rigidly secured at its ends to the legs 32, 33 of the Ipermanent magnet 34, and the actuated member 24 is secured to the to and extends from one leg32 to the yopposite leg 33 of'a permanent magnet 34.

armature 23 at a location between its fixed end 23 and its free eiid. Such rigid support bar 35 ma advantageously be subject to adjustment y employing the 4screw-threaded member having a thumb-head 36 for exerting a twist on the bar 36 within ranges of high pressure per square inch, thus attaining an adjustment imposing high compression on the bar 35 and maintaining the bar 35 rigid for every adjusted position.

Preferably, when our invention is applied to the rear or other inaccessible part of the piano or like instrument, we provide a rod or arm 37 extending at its free end 38 to the side or other readily accessible portion of the piano and attached at its opposite end tothe thumb-head 36 or equivalent, to enable theA adjusting member 36 to he regulated by pushing and pulling from time to time to any desired set osition. The free end 38 of the rod 37 may e loosely passed through `a, screweye 40 or equivalent.

The clamping and regulating bar 28 may advantageously be standardized and pro-- vided with a plurality of pairs of openings 41 and 42, 41a and 42a, 41" and 42", etc., for varying positions of the

set bolts

43, 44, or equivalent of the lradio reproducing unit, to accommodate ready variable positions of the unit relative to the treble bridge or other location with respect to the sounding board, and for dierent makes and types of pianos.

In Fig. 6, we have shown a modification of screw-threading the free end of the wire 24 and providing reverse-threading at the abutting end of the wire 26, and employing a turn-buckle 50 to adjust the iinal position. The wire 24 is soldered to the turn-buckle 50 at final4 setting as indicated at 51 and similarly at 52 to solder the wire 26 to the turnbuckle 50.

In Fig. 7, ,we show, our invention applied to a grand type of'piano in which the sounding board 11 is in horizontal position." In this instance, the plug 21 is inserted from the bottom similarly'as in an upright type o piano, and an opening 53 is drilled through the bridge of smaller diameter than the opening 19. The wire or rod `26 is passed through the opening 53 and brought into damped securement within' the leather plug 27, similarly as hereinabove set forth.

The thickness of the leather shielding 27 filo intervening between the actuated member 26 and the maple pin or equivalent should be of the magnitude of one-sixteenth of an inch 0r less to thereby provide for .a suiiiciently firm operating connection between the recipi rocally actuated member 26 and the pin, which operating connection. in both directions of reciprocatory action' is enhanced by the leather shielding 27.

Whereas, we have described our invention by reference to specific forms thereof, 1t wlll be understood that many changes and modi-r ications may be made without departing from the spirit of the invention.

We claim:

1. The combination. with a sounding board of a piano or the like, including elements for supporting the sounding board andfurther includin a bridge for said sounding board, said bri ge being provided with a bottomed recess, of an electro-magnetic device comprising coil means, an armature responsive to the variations of the current passing through the windin of said coil means, an element actuated y said armature, means for support-v ing said electro-ma etic device on said supporting elements, t e free end of said actuated element being disposed under pressure within said'bottomed recess, and means for adjusting the degree of pressure between vsa'id actuated element and said bridge.

2. The combination with a sounding board of a piano or the like, including elements for supporting'the sounding board and further includin a bridge 'for said soundingboard, said bri ge being provided with a bottomed recess, of an electro-magnetic device comprising coil means, an armature responsive to the variations of the current 4passing through the winding of said coil means, a core for said coil means, means for adjusting the normal clearance between sald armature'and .said core, an element actuated by said armature, means for supporting said electro-magnetic device on said supporting elements, the free end of said actuated element being disposed under tomed recess, an the means for adjustin degree of pressure between said actuatev element and said bridge.

i 3. The combination with a soundingboard of a piano or the like, includin elements for supporting the sounding boar and further includin a bridge for said sounding board, said bri e being provided with a bottomed recess, oig an electro-magnetic v vdevice comprising coil means, an armature responsive to the variations of the current passing through the winding of said coil means, a core for sald coil means, compressional means for adjusting the normal clearance between said armature and said core, an element actuated b said armature, means for supporting said elsectro-magnetic device on said supporting elements, `the free end of 'said actuated element being disposed under pressure within said bottomed recess, and means for ad'ust- `ing the degree of pressure between sai ac` tuated element and said bridge.

4. The combination with a sounding board of a piano or the like, including elements for supporting the sounding board, of an electromagnetic device comprismg coil means, an armature responsive to the varlations of the current passing through the windlng of said coil means, an element actuated by said armaments, said sounding board belng with la bottomed recess, a lplugv o sounding board. Y

6. The combination with a sounding board ressure within said bot-y tura-means for supporting 'said electro-mag- 1 .rial disposed atthe bottom of said bottomed recess,the free end of said actuated element being in contact under pressure with said disk, and means for adjusting the degree of pressure between said actuated element and said soundin board. y

5. vThe com ination with a sounding board of a piano or the like, including elements for supporting the sounding board, of an electro-magnetic device comprising coil means, an armature responsive to the variations .of the current passing through the winding of said coil means, an element actuated by said armature, means for supporting said electro-magnetic device on said supporting elerovided leather disposed at the bottom of said bottomed recess, the free end of said actuated element being in contact .under pressure with said disk, and'means for adjusting the degree of pressure between `said actuated-element and said of a piano or the like, including elements for supporting the sounding-board, and further including a bridge for said sounding board,

said bridge being provided with ya bottomed recess, of an electro-magnetic devicel com-A prising coil means, an element actuated by said coil means, means for Vsupporting said electra-magnetic device on sald supporting elements, a plug of resilient-dense material loo e disposed at the bottom of said bottomed recess, the freeend of saidactuated element being disposed underpressure against said plug, and meansfor adjusting the degree of pressure between said actuated element and said plug.

7. The combination'with asounding board ofa piano and the like, including a bridge and associated elements for supporting thesounding board, said brid e being rovided with a bottomed recess su stantial y at the location of the passage overv the brid e of the wires corresponding to the'middle tone, o an electro-magnetic device comprising coil means, an armature responsive to the variations of the current passing through the winding 'of said coil means, an element actuated y said armature, means for supporting said electro-magnetic device, the free end of said actuated element being disposed under pressure within said bottomed recess,

and means for adjusting the degree of pres- .sure between said actuated element and said bridge.

8. The combination with a sounding board j of a piano and the like including a bridge and associated elements for supportlng-the sounding board, of an electro-magnetic device com prising eoilv me'anganJ armature responsive of said actuated kelement being disposed uri-"10 to the Variations-dof the current passing der pressure against said sounding board through the winding;v of saidgcoil means, an and said bridge, and means oradjustin the element actuated `by-fsaid armature, means degree of pressure betweehisaid actuate ele- 5 forsupporting said electro-magnetic device nient and said bridge` l to locate said actuatedelement in Contact with In testimony whereof We have signed this l15 said sounding boardy corresponding to the specification this 16th day of June,';1927. looationof the'passing over said `bridge of v I JOHN M CO TE. the wiresv of the middle C tone, the free end CLARENCE PRYOR.