US1902614A - Control mechanism for vibra harps - Google Patents

Description

March 21, 1933. w 1,902,614

CONTROL MECHANISM FOR VIBRA HARPS Filed Oct. 1, 1931 2 Sheets-Sheet l JNVENIUR E :22? 0:23 NEJHS'.

March 21, 1933. H A BOWER 1,902,614

CONTROL MECHANISM FOR VIBRA HARPS Filed Oct. 1, 1931 2 Sheets-Sheet 2 a4 a3 3 2a a;

J W 36 ii 1M 37 24 W E IE5- Patented Mar. 21, 1933 UNITED STATES PATENT OFFICE CONTROL MECHANISM FOR VIIBRA HARPS Application filed October 1, 1931.

In vibra-harps a vibratile sound is given to the notes, usually by vibrators which operate in or adjacent the resonators. These vibrators usually rotate and give a tremolo 5 effect to the sound, being reproduced from the resonators. Usually, with this type of instrument there is no means provided for controlling the rate of the tremolo vibration and, therefore, the instrument has decided limitations in its musical quality and the effects which a musician may obtain from such an instrument are quite decidedly limited.

An object and feature of my invention is a constructionby'which the musician playing a resonant harp instrument of the xylophone type having resonators may control a tremolo or vibrato of the sound of each and every note and that he may increase or decrease the rate of the tremolo in accordance with the expression he desires to bring out in the composition being reproduced.

In this connection a feature of my mechanical construction giving this control is that I may obtain an instant variation from a retarded to an accelerated tremolo and that when using vibrators of a vibra-harp type of instrument I may obtain musical effects which are impossible in known resonant harp types of instruments.

Another object and feature of my invention is a construction bywhich I may manually set the controls to have a tremolo or Vibrato of a certain definite period and this will be the fundamental period which may be changed by increasing the rate.

Another object and feature of my construction is a setting device for the control mechanism which may be readily shifted to change the rate of the tremolo or vibrato of the resonators and that the rate so adjusted may be maintained. In this connection I have a plurality of different adjustment features allowing setting for relatively fine graduations in rate of tremolo or a coarser regulation of such rate.

In constructing my invention I preferably make use of an electric motor which, i through a geared drive, is arranged to operate the rotatable vibrators on the'upper like vibrator.

arm on each side of the pivot.

Serial No. 566,296.

exposed mouths of the resonator tubes. Usually, the tubes are arranged in a row, such tubes being vertical and having the vibrating keys positioned thereabove, and a shaft extends longitudinally of each row of resonators, such shaft being rotatable by the motor, and at each resonator there is a disk- The rate of rotation of these vibrators controls the rate of the tremolo or vibrato of the sound emitted by each resonator. My mechanism comprises a manual control devicefor changing the speed of the motor so that the vibrators will be rotated at a lesser or a greater speed as desired by the musician. I

In the specific construction illustrated, I employ a brake system to give a resistance to the rotation of the motor, this preferably being done by a. rotating disk against which brake pads may press. These pads are connected to a yoke and such yoke is slidable, the yoke being normally under a spring pressure to give a considerable resistance or braking effect to the rotation of the motor and, hence, maintaining this at a relatively low speed. I provide a pivoted operating lever, such lever having a long and a short The long arm extends in front of the keys and in a position to be engaged by the body of the musician so that by leaning slightly toward the instrument or away therefrom the lever may be operated. A movement of the long end of the lever toward the instrument through the medium of tension links exerts a pull on the yoke and decreases the pressure of the brake pads on the disk and, hence, allows acceleration of the motor and, therefore, of the rate of rotation of the vibrators. I

In order that I may obtain a manual setting of the instrument, I provide a fixed bracket secured to the instrument frame, and this has a screw threaded therethrough and such screw may operate along a block attached to the long end of the control lever, and, hence, set this lever in a desired position. to allow the motor to operate at a substantially constant speed as adjusted by the musician, which speed may manifestly be operation ofthe vibrators.

V fixed'position, do not'preve nt the musician '16 This screw is provided with a nut lock structure so that it may be locked and thus the desired rate of tremolo cannot be decreased beyond the limit set.

In the construction for giving readily ad'- justable changes to the speed'of the motor and, hence, of the vibrators, which is graduated for a coarse or fine degree of. change, I

provide a bar secured to the frame of the instrument and extending; horizontally therefrom, on which bar I have a rotatablecollar, which collar has a series'of notches on its diiferent faces, the collar'being held on the bar in adjusted positions by a set screw or the like. The collaris provided with a series of serrations difierent distances apart in which operates a nub on the long end'of the control lever. fine adjustment of the position of this con- 'trol lever may be obtained by the engageinent of the nub in any oneof the serrations, and by rotatingthe collar a coarse or fine may be readily made. These serrations, while holdingthe control lever in a from pressing inwardly on the manual control end of such lever to further increase the speed of the motor by decreasing the braking pressure.

lfarious'otherv features of improvement in the art will be apparent from the following description taken in connection with the drawings and the claims.

My invention is illustrated in the accompanying drawings, in which Fig; 1 is a planof' a vibra-harp type of instrument equipped with my invention, certain parts broken away;

Fig. 2 is a vertical transverse section on the line 2-2 of Fig. 1 in the direction of the; arrows, showing the note keys, the resonators, the vibrators, and the muting bar;

Fig. 3'is a vertical transverse section on the line'38 of Figil in the direction of the arrows, showing the electric motor and part of the control and drive mechanism in elevation Fig. 4 is a vertical transverse section showing part of the brakemechanism for the motor in section; V

Fig. 5 is a vertical longitudinal section on the line 55' of Fig. 4 in the direction of the arrows;

Fig. 6 is a plan with parts shown in sec tion of the manually operated adjusting mechanism for the control lever; i

F g. 1s a vertical longitudinal detail section on: the l1ne 77 of Fig. 6 in the direction of the arrows;

Fig; 8 is a vertical transverse section on the line 88'of Fig. 6'in the direction of the arrows;

Fig. 9 is a vertical transverse section on Therefore a coarse or a the line 99 of 6 in the direction of the arrows.

The vibra-harps are usually made with supporting rails 11 onwhich are mounted the sound producing bars 12, these generally being formed of metal. ranged in two. rows and between the rows These bars, are arthere is a damper rail 13 having a feltpad ltwhich is manipulated usually by a pedal, raising the felt. against one end of eachof the bars and'thereby damping their vibration. Below each bar there is a resonator tube 15 and extending along the top of each row of tubes is a rotatable shaft .16 having a disk-like vibrator 17. These vibrators are ofslightly less diameter than the internal diameter of the'tube to allow the free rotation and if a particular note is struck the resonator resounds' to this note giving a prolonged reproduction of suchnote and the rotating vibrator gives a tremolo or vibrato; effect to such note. Usually the shafts 16 are operated by electric motor 18, this motor being illustrated as having a reduction drive 19',;and a belt drive 20, to the pulleys 21"which rotate the shafts In my invention I have an extension 22 fan blades 2l which blow air over the motor 7 to keep the motor .cool'. Connected to a suitable end plate 25 there is a housing 26 which accommodates the disk 23 and part of the fan 24. In this housing there is a partition 27 which supports a rod 28, such rod passing through a perforation 29' in the front end wall 30 of'this housing. A collar 31 is slidabl'y mounted on the rod 28.. This collar has aprojection 32 with a perform tion 33 therethrough, through which perforation" extends a stud 34 secured in place by a cotter pin 85- and to such stud there is secured a yoke 36 on each end of which there is a felt braking pad 87. The connection of this yoke by the medium ofthe stud to the collar allows the yoke to turn slightly on the axis of this stud so'that the two pads illustrated bear with equal pressure on the face of the braking disk 23. A compression spring 88 coiled on the rod 28 and bearing between the front plate '30 and the collar tends to thrust the collar and hence, the yoke inwardly, applying the brake with considerable pressure. p

A slidable sleeve 39 is mounted on the rod 28 outside of the housing. This is limited in its sliding movement by means of a knurled hand operated nut 40 and a lock wing nut 41. The rod 28 may readily be attached or detached through the medium offormed of two wires or rods connected to a lug 46 secured to the collar 31. This bracket 44 has a perforation 47 through which extends a threaded finger 48, there being a jam nut 49 to limit the movement of such finger and the finger is secured to the short end 50 of an operating lever designated generally 51, which lever has a long end 52, the lever having a fulcrum at 53, such fulcrum being on a bracket 54 attached to the frame of the musical instrument, (note Fig. 2). This fulcrum may be adjustable on the bracket. For purposes of convenience, the long end 52' of the lever has an arcuate section 55 and has a bolted connection 56 to an outer section 57, to which outer section is added a wood pressure plate 58, this being in a position to be engaged by the lower part of the abdomen of the musician.

' A tension spring 59 is secured to the end of the short section 50 of the operating lever 51 and attached as indicated at 60 to the end plate 25 of the frame, thus giving an additional tension means to hold the lever with the short end inwardly and the long outer operating end 52 outwardly from the sound bars of the instrument.

In the operation of this part of the instrument, the pressures of the springs normally maintain the more or less certain pressure 011 the braking disk and will thus maintain the motor normally running at a nor 7 mal speed, this speed being fairly low so that the tremolo or vibrato effect on the sounds from the resonators have a comparatively short period. Themusi-cian playing the instrument may then, if he wishes a faster rate of tremolo or vibrato, lean against the outer end 52 of the operating lever, thus pressing this inwardly and exerting a tension on the link 45 and pulling outwardly on the collar 31 and, hence, releasing the pressure that the braking pads 27 bear on the disk 23. This allows the motor toinstantly speed up and drive the vibrator 17 at a higher rate of speed. The amount of leverage of the lever 51 is so adjusted that a comparatively long are of movement is necessary for the end 52 to give a small movement to the short end of the lever and thereby controls the motor through a wide range of speed.

A setting al'ustment for the lever 51. to set the initial brake pressure is provided by the following mechanism: A two-armed bracket or brace 61 is secured to the front rail 11 of the musical instrument. This bracket has a head 62 with a threaded perforation 63 through which extends a threaded tube 64, such tube having a knurled hand wheel 65 secured to its outer end. The inner end of this tube bears against a block 66 which has a pressure exerting nub 67. A pair of channel-shaped guides 68 (note Figs. 6 and 7) are secured to the block 66 and instrument.

The arcuate section 55 of the outer por- 3 tion 52 of the lever 51 has a collar '7 4 secured thereto from which there is an upwardly extending plate 7 5, this-plate havin' a bend as indicated at 76 (note Fig. 8). T is plate I has an elongated recess 77 into which the operating end of the nub 67 bears. There- 7 fore, by this construction, by operating the knurled hand wheel 65 one way or the other, the threaded tube 64 is forced inwardly or outwardly, carrying the head 66 and the nub 67 and through the medium. of the plate and the collar 74 moves the long end of the lever 51 inwardly or outwardly; The threads on the tube 64 are preferably of a coarse pitch to give a quick adjustment. This adjustment'may be arranged to set the initial pressure of the braking pads and thus allow the motor to operate at a substantially definite speed but does not in any manner interfere with the further inward movement of'the lever due to inward pressure on the end 52. This gives the musician an initial setting to produce the lowest rate of tremolo or vibrato which he desires.

'A readily releasable adjuster device 78 employs a rod 79 secured to the frame of the On such rod there is a collar 80, this being adjustable and having a set screw 81 to clamp such in the adjusted positions; This collar has sets of serrations 82 .and 83, these being of different degrees of coarseness.

Any one set may be brought into a position to be engaged by an elongated nub 84 on the portion 55 of the lever 51. A compression spring 85 operating between the instrument and the Washer 86 is under compression to thrust-outwardly on the collar. The collar may, therefore, readily be adjusted to retain the control arm in any one of the serrations but yet will allow movement of such arm in order to hold the nub 84 in a tight fit in the serrations. An abutment nut 88 is threaded on rod 7 9 and forms 'an adjustable limit to the outward movement of collar 80.

A rod 87 has a wedging end accommodated in a deep socket 7 9 in rod 79, and the opposite end is provided with a tension spring 89 connected to the part 55 of the lever 51. It will be seen, therefore, that-by rotating the collar different types of-serrations may be brought into engagement with the nub and that various degreesof removement ofthc body of the musician,.w-ith-' out inter-feringwith the operation ot the damper rail 13 (which is actuated by a foot pedali). ,A'slight movement of the body of the. musician to? or from thetlreys gives a wide variation tothe tremolo orvibrato effects.

' Various chances ma. be-made in the features: of the Vi-nvention 'without departing from the spirit or scope thereof as definedv in the appended claims.

"I claim:

1. A musci-al instrument having a porous sion means to produce musical tones of different pitches, a tubl'ar resonator to respond to each different tone, a vibrator for each resonatorgxa driving means'to operate said vibrators, a setting means to initially set the driving means to; operate the vibrators at. a certain: predetermined.period of vibration, and a. control means operable by the body of the player, of. the instrument to increase the rate ofdrive to decrease the period; of vibration.

2; A musical instrument as claimed. in claim 1 havlng in. addit on an" ad usting means to regulate the control: means for -.changing' and. retainingthe driving means to operatethe vibrators at predetermined: periods of vibration, said adjusting means having a slip connection to allow operation of said control. means;

V A musical instrumentthaving a row of sound-bars to produce musical tones by per-v cussion, a tubular resonator: to respond to each tone,-.a vibrator for each. resonator, said vibrators bemg connected together to oper- I 7 claim 6, themeans to control the motor comate in unison, amotor 'to dri've'saidvibrators, a pivotally mounted control lever having, one end positioned to be en-gaged. by the player of' the instrument and the other end having, an operative connection tothe motor to vary the" speed thereof whereby on operation of said: lever the player of the instrument may change the speed: ot the motor..

.4; A musical instrument as claimed in claim 8,. a bracket. connected to the instrumentv and having an adjusting screw therein, means interengaging between said screw and the lever to position said leveri-n an initial position to give a relatively slow rate of vibration of the vibrators, said lever being movableto increase the speed of the motor and hence the. rateaof vibration. of the vibrators. I V 1 5. A musical instrument having a rowof percussion sound bars to-produce tones of different pitches, a tubular resonator posi-i connection to the motor to vary the speed thereof, a setting device. comprising a bracket mounted on the instrument and having ascrew threaded rod with an. interconnection between said rod andthe lever to adjust the lever to an initial position to give a rela tively slow speed to the motor and hence to the vibrators, said lever being operable to increase the speed of the; motor and. hence of the vibrators, an ad usting means comprising a rod secured to the lnstrumenthaving a collar with serrations adjustably mounted thereon, and means on the lever to engage said serrations to adjust the posi- 131011 of the lever independent ot the 1n1t1al setting of vthe lever, said serrations permitting movement of thelever to change the speed of the motor and hence of the vibrators. w

V 6. A musical instrument having a series of sound bars arranged in a horizontal supporting frame, a resonator beneath each'bar,

a: vibrator on each resonator, a motor drive to all of the vibrators to operate same in unison, a control lever pivoted adjacent one end of the sound bar supporting frame and having an operating. end extending substantially parallel to saidv frame spaced therefrom and adapted tobe engaged bythe body of the player when playing on the sound bars, and means actuated by said lever to control the speed of the motor and hence of the vibrators. V

7. A musical instrument as claimed in prising a brake disk actuated by the motor, a brake pad, and aconnection fromthe levor to adjust the brake pad in relation to the brake disk.

8. A musical instrument as claimed in claim '6, the sound bar, supporting frame 1 being adapted to engage said lever to adjust the lever tov an initial position to determine the lowest vibration of the vibrators, the lever being operable by the movement of the body of a player to release the lever from the end of the screw-to accelerate the vibrators.

9. A musical instrument as claimed in claim 6, a releasable adjuster for the control lever comprising a rod secured to the frame and extending outwardly therefrom, a collar on said rod having a series of notches, the control lever having a nub to engage in any one of the notches, said nub and control lever being readily disengaged from said notches.

10. A musical instrument having a horizontal frame with a row of percussion bars extending therealong, a resonator beneath each bar, each resonator having a rotatable vibrator, a motor having a drive to the vibrators to rotate all of the vibrators at the same speed, said motor having a brake disk and abrake pad to engage therewith, spring means to normally urge the brake pad into engagement with the brake disk, a control lever mounted on a vertical pivot, the control end of the lever extending substantially parallel to one side of the frame and spaced therefrom, the opposite end of the lever having a link mechanism to connect to the brake pad to release the pressure of the brake pad and the brake disk when said lever is pressed inwardly by the body of the instrument player actuating such instrument and thereby varying the speed of the motor and of the vibrators.

11. A musical instrument as claimed in claim 10, a setting adjustment device comprising a bracket secured to the frame extending outwardly, said bracket having a screw operating therein, the bracket forming guides for the movement of the screw, the screw having a pointed end, and means on the. control lever to engage such end whereby the initial adjustment of the screw may regulate the pressure of the brake pad on the brake disk.

12. A musical instrument as claimed in claim 10, a releasable adjuster comprising a rod extending outwardly from the frame and having a movable collar thereon, a spring normally urging said collar in one direction, a clamp screw to retain the collar stationary, said collar having a series of transverse notches, the control lever having a nub to engage therein, and spring means to urge the nub into engagement with the notches, said nub being readily released from the notches by a horizontal movement of the control lever.

13. A musical instrument as claimed in claim 10, a setting adjustment device comprising a. bracket secured to the frame extending outwardly, said bracket having a screw operating therein, the bracket forming guides for the movement of the screw, the screw having a pointed end, and means on the control lever to engage such end whereby the initial adjustment of the screw may regulate the pressure of the brake pad on the brake disk,'a releasable adjuster comprising i a rod extending outwardly from the frame and having a movable collar thereon, a spring normally urging said collar in one direction, a clamp screw to retain the collar stationary, said collar having a series of transverse notches, the control lever having a nub to engage therein, and spring means to urge the nub into engagement with the notches, said nub being readily released from the notches by a horizontal movement of the control lever.

In testimony whereof I have signed my name to this specification.

HARRY A. BOWER.

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