US2484745A - Damper operating mechanism for - Google Patents

Description

Oct. 1l, 1949. P. H. ROWE 2,484,745

DAMPER OPERATING MECHANISM FOR ELECTRIC PERCUSSION INSTRUMENTS Filed April 50, 1947 3 Sheets-Sheet 1 Cet. l1, 1949; P. H. RowE 2,484,745

DAMPER OPERATING MECHANISM FOR ELECTRIC PERCUSSION INSTRUMENTS Filed April 50, 1947 4 5 Sheets-Sheet 2 f 1 l l u nl l u x4 LMM 30 lllw'" /f/ 46/ 45 L MW// Z2 25 29 3a 44 I-g 4 IIL.. IW.

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Ary-ORME Oct. ll, 1949. P. H. RowE l DAMPER OPERATING MECHANISM FOR ELECTRIC PERCUSSION INSTRUMENTS Filed April 30, 1947 3 Sheets-Sheet 3 Irl.

Patented Oct. 11, r`1949 DAIVIPER OPERATING MECHANISM FOR ELECTRIC PERCUSSION INSTRUMENTS Paul H. Rowe, Los Angeles, Calif., assigner to Maas-Rowe Electromusic Corporation, Los Angeles, Calif., a corporation of California Application April 30, 1947, Serial No. 744,87.6

13 Claims.

This invention relates to an electrical percussion instrument of the type in which vmetal bars are struck to produce musical tone by vibration of the rod.

Usually, the bars of varying lengths are suspended side by side` in closely spaced relation. The suspension permits some freedom of motion, whereby they may freely vibrate. Ay striker is associated with each bar andoperated by an electromagnet, or solenoid, and a plunger `of magnetic material. A common arrangement is one in which the strikers lare located belowthe bars, a keyboard being provided for controlling the e1ectromagnet circuits.

A damper, usually of feltfmay be arranged for each bar, to stop the vibrations of the bar except when the striker associated with the bar is operated. It is one kof the objects of this invention to improve, in general, 'the manner in which the dampers are operated. e

It is another object kol." this'inventionto' make it possible to support the damper in 4a 'compact and simple manner on* the* corresponding lstriker'. For this purpose, a special form of supportjfor the damper is utilized, and which' is compact and of such small cross section that it may readily pass between adjacentbars, so'thatthe' damper may rest on the top ofthe bar-and therebyl suspend the plunger carrying the striker.

At times it may bedesirable to permit the bars to vibrate sympathetically when one of the bars is struck. This entails the necessity of raising all of the dampers from the bars. A-It ris anotherobject of this inventionto'provide `a. simple mecha'- nism for raising therdampers, and especially by the aid of electromagnetsthatoperate Ito lift the plungers slightlywithout bringing them into contact with the bars. i f

Preferably, this lifting action is controlled from thekeyboardbythe aid'ofv one or more electromagnets. -f It is-still another object/of vthis invention to provide an arrangementof this character in which` only a small electric lpower is needed to lift all of the dampers. This isaccom` plished by aid of force-multiplyingk devices,` such as levers. It is stillanother-objectfof this invention to make it 4possible still further to reduce the `power for this purpose bya'idofa specic lever arrangement. I 'v This invention possesses many Vothersadvantages, and has other objects'which may be made more easily apparent fromKY a considerationof one embodiment of-the invention. For thisy pur# pose there is shown -aform linfther drawings accompanying and' forming part fr oil the ypresent 2 specification. This form will now be described in detail, illustrating the general principles of the invention; but it is to be understood that this detailed description is not to be taken in a limiting sense, since the scope of this invention is best defined by the appended claims.

Referring to the drawings:

Figure 1 is a side elevation of an electrical musical instrument incorporating the invention;

Fig. 2 is a sectional view, taken along plane 2-2 of Fig. 1;

Fig. 3 is an enlargedfragmentary longitudinal, sectional View of the instrument, the elements being shown in an alternative position;

Figs. 4 and 5 are sectional views, taken along planes 4--4 and 5-5 respectively of Fig. 3;

Fig. 6 is a sectional view, taken along plane 6-6 of Fig. 4;

Fig. 7 is a sectional view, taken along plane 1--1 of Fig. 5; and

Fig. 8 is an enlarged sectional view, taken along plane 8-8 of Fig. 3.

The instrument includes a plurality of horizontally arranged resonant bars l. One of these 'bars is shown in Fig. 4. However, they are of different lengths and may include reduced portions, such as at 2, in order to obtain the desired tone when the bar is struck by a striker in a manner to be hereinafter described.

These bars l are arranged in closely spaced relationship, as shownmost clearly in Fig. 1.

The support for these bars is provided by the aid of a wood frame comprising spaced upper and lower portions 3 and 4 (Fig. 1). The two sections of the frame 3 andr 4 are held apart by the end spacers 5, the bars l extending between these sections. Each of the frame sections, furthermore, has a central, rectangular opening extending substantially the entire length of the bar I from one side of the frame to the other. The bars I, furthermore, are suspended by the air of cords '6 from the top frame 3. These cords are anchored to a series of anchors l in the form of screw eyes threaded into the top of the frame 3. Since the specific manner of suspending the bars forms no part of the present invention, it is sufcient to state that these suspensions occur adjacent the ends of the bars, by the aid of the cords, in a manner described and claimed in a copending application, Ser. No. 744,875, led April 30, 1947, in the name of Paul H. Rowe.

The frame structure 3-4-5 is mounted on a pair of wood cross-pieces 8 by the aid of the interposed felt washers 9. These cross-pieces, in turn, are supported 'on a main base structure 3 including a base plate I and the end pieces II and I2.

This mounting may be accomplished by the aid of a pair of screws I3 that pass through the support 8 and include the rubber mountings I4.

Beneath the frame structure there are provided electromagnetically operated striker devices which are shown most clearly in Figs. 4 and 6. In order to provide a support for these devices, a pair of longitudinally extending wood members or strips i5 and I5 are anchored at their ends in the supports 8, as shown most clearly in Fig. 2.

In turn, as shown most clearly in Fig. 4, these wood members support a hollow metal frame ITI beneath their lower edges. A wood strip I8 .can be provided on one side of the frame toserve asra support for various electrical terminals` not shown.

The frame I'I extends from one end to the other of the instrument. Within the frame are supported the electromagnet coils I9, having axes transverse to the bars I. There are two rows of these coils in staggered relation. These coils provide electromagnetic power for operating the striker devices 2i) (Figs. 4 and 6).

In order that these Strikers may be guided in a vertical direction, the top and bottom of frame I'I have a plurality of apertures 2I respectively coaxial with the axes of the coils I9. In theseapertures are located insulation sleeves 22 which serve as guides for the striker mechanisms. These sleeves extend completely through the frame.

When a specific coil I9 is energized, it will serve to draw in a hollow magnetic core 23 that is `guided in the sleeve 2U. Accordingly, when a corresponding coil I9 is energized, the core 23 is violently pulled upwardly and carries the striker mechanism upwardly to hit the bar I.

Each striker mechanism includes-a rectangular wood strip 24 (Fig. 6) that is anchored at its lower end in the core 23. At its upper end, it carries a felt cover 24 that comes into contact with the bar I when the corresponding electromagnet is en- 'ergized In the unenergized position yindicated in Fig. l, the tops of strips 24 are spaced a considerable distance below the corresponding bar I.

Each of the striker mechanisms is suspended freely within the sleeve 22 by the aid of a damper 25 wliich'engages the upper sde'of the bar I. The damper 25 (Figs. 3, 4, and 6) may be formed Zby a pair of felt members between which is accommodated one leg 26 of a damper supporting rod 2l. This damper supporting rod is made from relatively thin wire, and can readily pass between adjacent bars I. Its lower end 23 extends `horizontally and enters transversely into the striker ZI). Preferably, this end 28 may be knurled to form a tight iit.

The core 23 of each of the mechanisms .forms a plunger for the corresponding solenoid coil I9. In playing the instrument, the core is ultimately centralized within the coil I9. Each energization carries the striker mechanism upwardly, and a single blow is imparted to the bar I, after which I the plunger falls back to central position; and when the coil is deenergized, the striker mechanism falls to the lowered position illustrated in Fig. l. The damper pad 25, while the corresponding coil I9 is energized, is free of bar I, and permits the bar I to have a free vibration until the plunger returns to its lowermost position.

At times it is required that all of the dampers 25 for all of the bars I be released from the :bars

in order to cause the bars to sustain a sympathetic vibration. This is accomplished in the .present instance by the aid of a wood platform 29 (Figs. 1, 3, and 4) Which extends underneath all the cores 23 and lengthwise of the instrument. Preferably, a felt pad 30 is disposed above the platform. This platform 2.9 is shown in the inactive position of Fig. 1. It is, however, shown in raised position in Figs. 3 and 4. The raised position of the plunger is illustrated in Fig. 6. In this position all of the damper pads 25 have been lifted away from the bars I.

The ends of the platform 29, as shown most 'clearly inFig. `3, are :received in slots 3I formed vertically in the :central portion of the supports Id land I2.

The mechanism for optionally raising the plat- 'form "to a sufficient distance to release all of the pads without striking the bars I will now be described.

On one side of the instrument, and supported on thesupporting member I5, are a pair of levers 32 and 33. Corresponding levers 34 and 35 are similarly supported on the supporting member I6.

These levers are Veach mounted for pivotal movement on the supports I5 .and 'I 6, as indicated most clearly in Fig. 4. Thus, passing through and forming a .pivot ,for .the right-hand end of lever 32 there is a wood screw .36. This wood screw passes .throughabushng 31 accommodated between the washers 3B and .39. On the bushing 31 `is .pivoted the lever32.

Each of the levers 32, 33, 34, .andv35 is connected, as by .a link 49, to the platform 29. Accordingly, when levers n32 .and 33 are raised, .the links serve to raise the .platform 29. Since there are four .such links arranged symmetrically, the platform is lifted evenly tocontact all of the cores 23 substantially simultaneously.

The link 40 is hooked .at .its upper end over a screw 4I (Eig. 3) .carried by the lever. As its lowerend,as shownin Fig. .8, it passes through a screw-,eye 42 that -is attached to the platform 29. This screw-eye may be lined with .a felt washer 43. Furthermore, the link 4.0 .has an adjustable stop 44 beneath 4the eye 42. y This stop is held in any adustedposition by the ,aid ofthe set screw 45 which extends `transversely.of the link 40, and 1which `passes into the member 44. A felt pad or washer 46 .is interposed between .the stop 44 and the-eye42.

Accordingly, :by proper adjustmentof the position of all lof the .stops 44, movement of the four levers 32-35 can bemadesuch as to elevate the platform `to the positionof Fig. 3.

Operation of .allof the levers `is accomplished by the aid of solenoids, one for each lever. The solenoidstructure for llever132 will be described, and it 'will be Vunderstood that similar solenoid structures are lemployed rior `the remaining levers.

Thus, as .shownmost clearlyin Figs. 3 and 5, a coil -4'I .is supported in the frame II, and carries a core-48 of the same-:generalfcharacter as vcores 23. InfFig. 5,.-the-core `48..:lsshown in the position that it `assumes zwhen -thecoil 41 is energized.

The hollow core 48 .carries a wood strip 49 (Figs. 5.and 7).. This'wood-strip is connected to the lever 32 by the aid of-a fstiff -Wire 50, which passes through -a :large .clearance aperture 5I in .the supporting -strip 1li. .In lorder *to render the operation :on the flever .-nolseless, felt sleeves 52 and 53 Aaredisposed-On the Wire 50. The upper edge -of-the apertureil .serves vas a limit vfor the vupward movementof thelever 82.

fase-m45 In order that small solenoidcoils 41,.uslng only limited power, may be provided to lift the platform 2.9 and all of the cores 23;, use is madeof an auxiliary spring force associatedr with lever 32 and lever 34. Thus, a tension spring 54 is anchored at its left-hand end toy a screw-eye 55 attached adjacent the free end of thelever 32. Its other end is anchored to a Wire 56 that passes through stationary guides 5l mounted. on the support I5, and that has an adjustable stop 58.

In the position of Fig. 1, in which the platform 29 is in the inactive position, the direction of the force exerted by the spring is such that this force passes quite close to the pivot of the lever 32. Accordingly, in this position the torque tending to turn the lever 32 in a Aclockwise direction, due to the spring tension, is very small and not suiiicient to raise the platform and its associated parts. The weight of these parts is sufficient, when the coils 4l are de-energized, to carry the platform 29 to its l'owermost position.

However, just as soon as the .plungers 48 are elevated slightly, the torque arm of the spring force increases rapidly. Accordingly, the spring tension helps materially to raise 'the platform.

The inventor claims:

1. In an electric percussion instrument: a suspended horizontal resonant bar; a striker below the bar; a damper 'resting on the bar and above it; a connection between the damper and the striker; and electromagnetic means for operating said striker, including a core suspended by the damper.

2. In an electric percussionifnstrument: aphirality of spaced parallel resonant bars; a plurality of strikers respectively for the bars and movable transverse to the axis of the bars; a damper for each bar located 'on the opposite side of the bar from the striker; a connection between each striker and the corresponding damper and passing between adjacent bars; and electromagnetic means for operating each striker including a core for each striker suspended by the respective damper.

3. In an electric percussion instrument: a plurality of horizontally arranged, parallel spaced resonant bars; a plurality of strikers respectively for the bars and disposed to move upwardly against the bars; electromagnets having plungers connected to the strikers; a damper for each bar and disposed above the bars; and a connection between the damper and striker of each bar, and passing between adjacent bars; the damper thereby serving to suspend the associated striker and plunger from the bar.

fl. In an electric percussion instrument: a plurality of spaced parallel resonant bars; a plurality of strikers respectively for the bars and movable transverse to the axis of the bars; a damper for each bar located on the opposite side of the bar from the striker; a connection between each striker and the corresponding damper and passing between adjacent bars; and means for simultaneously moving a plurality of the strikers but not into contact with the bars, for moving the corresponding dampers off the bars.

5. In an electric percussion instrument: a plurality of horizontally arranged, parallel spaced resonant bars; a plurality of strikers respectively for the bars and disposed to move upwardly against the bars; electromagnets having plungers connected to the strikers; a damper for each bar and disposed above the bars; a connection between the damper and striker of each bar,

:and passing between adjacent bars; the. damper vthereby serving to suspend the associatedy striker and plunger from the bar; and means for simultaneously lifting a plurality 'of the plungers to release the dampers, said movement being insufficient to move the strikers into contact with the bars.

6. In an electric percussion instrument: aplurality of horizontally arranged, parallel spaced resonant bars; a plurality of strikers respectively for theV bars and disposed to move upwardly against the bars; electromagnets having plungers connected to the strikers; a damper for each bar and disposed above the bars; a connection between the damper and striker of each bar, and passing between adjacent bars; the damper thereby serving to suspend the associated striker and plunger from the bar; a vertically movable member beneath the plungers; and means for moving said member to lift a plurality of plungers for releasing the dampers, said movement being insuicient to move the strikers into contact with the bars.

7. In an electric percussion instrument: a plurality of horizontally arranged, parallel spaced resonant bars; a plurality of strikers respectively for the bars and disposed to move upwardly against the bars; electromagnets having plungers connected to the strikers; a damper for each bar and disposed above the bars; a connection between the damper and striker of each bar, and passing between adjacent bars.; the damper thereby serving to suspend the associated striker and plunger from the bar; a platform normally spaced below the plungers; and means for moving the platform to engage the lower ends of the plungers and to release the dampers `from the bars.

8. In an electric percussion instrument: va plurality of horizontally arranged. parallel spaced resonant bars; a plurality of strikers respectively for the bars and disposed to move upwardly against the bars; electromagnets having plungers connected to the strikers; a damper for each bar and disposed above the bars; a connection between the damper and striker of each bar, and passing between adjacent bars; the damper thereby serving to suspend the associated striker and plunger from the bar; a common means for engaging the lower ends of the plungers; and means for raising said common means, comprising a lever; a link between the lever and said common means; and an electromagnet having a plunger connected to the lever.

9.' In an electric percussion instrument: a plurality of horizontally arranged, parallel spaced resonant bars; a plurality of strikers respectively for the bars and disposed to move upwardly against the bars; electromagnets having plungers connected to the strikers; a damper for each bar and disposed above the bars; a connection between the damper and striker of each bar, and passing between adjacent bars; the damper thereby serving to suspend the associated striker and plunger from the bar; a common means for engaging the lower ends of the plungers; and means for raising said common means, comprising a lever; a link between the lever and said common means; an electromagnet having a plunger connected to the lever; and a spring connection urging the lever in a lifting direction, the direction of the force of the spring being quite close to the axis of the lever when the lever is in inactive position, whereby the weight imposed on the lever when the electromagnet `7 'operating the lever is deenergized, is suicient to 'cause reengagement of the dampers with the bars.

' 10. In an electric percussion instrument: a plurality of horizontally arranged, parallel spaced resonant bars; a plurality of strikers respectively for the bars and disposed to move upwardly against the bars; electromagnets having plungers 'connected to the strikers; a damper for each bar and disposed above the bars; a connection between the damper and striker of each bar, and passing vbetween adjacent bars; the damper thereby serving to suspend the associated striker and plunger from the bar; a member beneath the plungers and normally out of contact therewith; a plurality of levers connected to the member to raise it and thereby release the dempers; and electromagnets respectively connected to the levers for operating them.

11. In an electric percussion instrument: a plurality of horizontally arranged, parallel spaced resonant bars; a plurality of strikers respectively for the bars and disposed to move upwardly against the bars; eleotromagnets having plungers connected to the strikers; a damper for each bar and disposed above the bars; a connection between the damper and striker of each bar, and passing between adjacent bars; the damper thereby` serving to suspend the associated striker and plunger from the bar; a member beneath the plungers and normally out of contact therewith; a plurality of levers connected to the member to raise it and thereby release the dampers; said levers being angularly movable on spaced parallel axes; electromagnets respectively connected to the levers for operating them; and a spring connection between one lever and a stationary point for assisting the electromagnet, the direction of the spring force being close to the aXis of the respective lever, and increasing as the lever operates; the weight of the member and its as- 8 sociated parts being sufficient when the lever operating electromagnets are deenergized, to return the member to inactive position.

12. In anelectric percussion instrument: a plurality of spaced resonant elements; a plurality of'strikers respectively for each element; a damper for each element; `a connection between the damperand the striker of each element; independently operable means for operating the strikers so as to strike the elements; and means for simultaneously moving the strikers toward the elements but short of contact of the strikers with the elements, and thereby moving the dampers out of contact with their respective elements.

13. In an electric percussion instrument: a plurality oi spaced resonant elements; a plurality of strikers respectively for each element; a damper for each element; electromagnetic means for operating each of said strikers, and including a core to which the respective striker is attached; a damper foreach element carried by the striker for the element, said damper serving to suspend the core; and means for simultaneously moving said cores for releasing the dampers, the movementor the cores being insufficient to cause contact between the strikers and the elements.

PAUL H. ROWE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS

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