US2025875A

US2025875A - Stringed musical instrument

Info

Publication number: US2025875A
Application number: US708571A
Authority: US
Inventors: Lloyd A Loar
Original assignee: ACOUSTI LECTRIC Co
Current assignee: ACOUSTI LECTRIC Co; ACOUSTI-LECTRIC Co
Priority date: 1934-01-27
Filing date: 1934-01-27
Publication date: 1935-12-31
Anticipated expiration: 1952-12-31

Description

Dec. 31, 1935. AJLQAR 2,025,875

STRINGED MUSICAL INSTRUMENT Filed Jan. 27, 1934 2 Sheets-Sheet 1 K5" 7- 5 Z djlyVVENTOR A TTORNEYS Dec. 31, 1935. LOAR 7 2,025,875

STRINGED MUSICAL INSTRUMENT Filed Jan. 27, 1934 2 Sheets-Sheet 2 INVENTOR.

007d 4 Low" ATTORNEYS an improved stringed Patented Dec. 31, 1935 UNITED STATES PATENT OFF-ICE 2,025,875 s'mmcnn MUSICAL INSTRUMENT Lloyd A. Loan; Kalamazoo, Mich., "assignoi, by

memo assignments,

to Acousti-Lectric Company, Kalamazoo, Mich., a, corporation of Michigan 23 Claims.

My invention relates to musical instruments and more particularly to stringed instruments of the lute and viol type. A

The main object of my invention is to provide instrument having an electrical pick-up associated therewith and means for adjusting the string bridge so that the instrument can be used either as a generator or a musical instrument or both.

Another object is to provide an improved bridge construction in an instrument of this character so that the vibration of the string bridge acts to vibrate both the belly sounding board and the back sounding board of the sound box sitrlrliultaneously-and oppositely relative to each er. I

A further object is to provide means for supporting the string bridge clear of the sounding boards.

Objects relating to details and economies of my invention will appear from the description to follow. The invention is defined and pointed out in the claims.

A structure which is a'preferred embodiment of my invention is illustrated in the accompanying drawings, in which:

Fig. 1 is a top plan view of aguitar embodying the features of my invention and an amplifier and loud speaker associated therewith, the latter being shown diagrammatically.

Fig. 2 is an enlarged fragmentary longitudinal section on a line corresponding to line 22 of Figs. 1, 3 and 4.

Fig. 3 is an enlarged transverse section on a line corresponding to line 3-3 of Figs. 1, 2 and 4.

Fig. 4 is an enlarged fragmentary view partially in section and partially in plan, the section-being taken on a line corresponding to line 4 4 of Fig. 6.

Fig. 5 is an enlarged fragmentary top plan view of the parts with the armature or bridge support removed.

Fig. 6 is a fragmentary sectional view taken on a line corresponding to line 66 of Figs. 4 and 5.

In the embodiment of my invention illustrated by the drawings, numeral I indicates a guitar comprising a sound box 2, a tailpiece 3, a finger piece 4, and strings 5 connected between the tailpiece and the finger piece in the usual manner A hand or finger rest is indicated at 6. The amplifier 1 and loud speaker 8 areof suitable construction, these parts being similar to or equivalent to a radio receiver.

The sound box 2 comprises a belly sounding board 9 and a back sounding board l0, these parts being held in assembled spaced relation by means of the side wall II. I preferably arrange the parts so that the lower edge l2 of the side wall extends over or below the back sounding t board to provide a guard rim toprevent the clothing of the operator from coming in contact with the back sounding board. This projecting edge or flange I2 is backed up by the reinforcing member l3 mounted on the inner side thereof and in 1 contact with the back sounding board.

In one side of the side wall II, I provide a substantially rectangular drawer opening l4 for the drawer I 5 which has a front panel l6 fittingly filling such opening. To support the drawer I 5, I mount shelves or ledges l7, I! on opposite inner' sides of the side wall and with their upper surfaces on a level with the lower edge of the drawer opening. The upper surface of each shelf or ledge I1 is covered with a layer I8 of felt or other similar vibration absorbent material. An intermediate block or post I9 and an end block 20 are mounted on the drawer l5 at one side of its longitudinal center to carry the string bridge supportll of magnetic material having a free end 22 overhanging thelopposite side of the longitudinal center of the drawer.

The stator 23 of an electrical pick-up, in this case magnetic, is fixed to the drawer IS in operative relation to the free end 22 of the string bridge support, the latter constituting the armature of the pick-up. The stator 23 of the pick-up is connected to the amplifier I by means of insulated conductors 43 in the conduit 24 which passes through an opening 25 provided therefor in the base 26 of the instrument. The stator 23 consists of a permanent magnet 44 of horseshoe shape fixed to the drawer l5 and having

upright pole pieces

45 and 46 providing the core of a winding 41 mounted on the horseshoe magnet. The upper end of the pole pieces 45 and .48 are spaced from the free end 22 of the string bridge support to provide air gaps 48 and 49 variable in accordance with the vibration of the strings of the instrument. The permanent magnet provides a magnetic fiux in a path passing through the pole piece 45, air gap 48, armature 22, air gap 49, pole piece 46, and permanent magnet 44. Thus, string vibrations are transmitted through the string bridge 50 t 28 to the armature 22, vibration of the armature the conductors .13. In this way string vibrations are averted into sound.

The stator 23 and armature of the pick-up are arranged to form an electrical generator the operation of which is responsive to the vibration of the strings 5 of the instrument. The generated impulses are amplified by the amplifier i so that the loud speaker 8 produces a tone corresponding to that of the strings. The string vibrations are imparted to the armature of the pick-up through the string bridge 28. Thus, the string vibrations are transformed into a sound which is a' true reproduction of the note set up by the vibration of the strings.

The belly sounding board 9 is provided with a transverse slot 2? for the passage of the string bridge 28 which is mounted on the support 2 i the bridge having a relatively large aperture 29 dividing the lower half of the bridge and provided with an upper edge 30 arranged in parallel relation with the top of the bridge. A layer of felt 3! or other similar material is disposed between the string bridge and the support. With the parts thus arranged, the drawer l5 can be readily 'removed from the sound box by elevating the string bridge clear of its support.

On the back sounding board l0, I mount a back bridge 32 which extends upwardly through and clear of the transverse slot, 33 provided therefor in the belly sounding board. On this back bridge 32 as a fulcrum, I mount a treble bridge lever 35 and a bass bridge lever 35 in side-by-side relation and extending at one end under the upper edge 30 of the aperture in'the string bridge 28. I connect the opposite ends of the levers to the belly sounding board 9 by means of adjusting bolts or tension members 36, 36. By adjusting the tension mem bers 36, the string bridge 28 can be lifted from the support 2| to any desired degree. As the tension members 36, 3e are tightened, they press the levers 3 3 and 35 down on the back bridge 32 and lift the string bridge 28' from its position on the pick-up armature. By tightening the tension members sufiiciently, all of the string pressure on the string bridge can be transferred to the back sounding board it through the back bridge 32 and to the belly sounding board 9 through the tension member's. When this is done, the sounding boards amplify the string'vibration and the pick-up device will receive none of it directly. With the parts adjusted in this manner, the instrument is playableas a conventional musical instrument. By changing the lever arms, the ratio of vibration imparted to the sounding boards relative to each other can be changed. As the bolts 36, 36 are loosened, the string pressure is removed from the sounding boards and returned to the string bridge support or pick-up armature. With this adjustment, the sounding boards are practically inoperative .and all of the string vibration directly controls the vibration of i the pick-up armature. This construction permits many special adjustments to meet special occasions.

With the usual sound-board amplification, and

a usual type pick-up on the sound board, unless the speaker is near the player, the tone from the speaker will be behind or lag behind that from the sound board. In the case of a listener, he will hear the tone from the source'nearento him first. If this difference of distances from the two sources is suificient the total effect will be one of confusion, especially in rapid playing. The only way to avoid this with the usual type of instrumentfand pick-up is-always to have the instruaoaaers ment and loud speaker close together. In many casesthis is not desirable.

With the usual type of pick-up used with no sound board or resonance structure, to mechanically amplify the tone the instrument is always 5 dependent on the amplifier-speaker combination and an electric outlet to operate the amplifier for audibility.

My invention permits the instrument to be quickly adjusted to meet either situation,

Forspecial occasions, where tone from both mechanical and electrical amplification is desirable, the tension members 3M and 362 are adjusted to provide string pressure on both the pickup armature and sound boards 9 and it. This condition could arise from broadcasting where the microphone is dispensed with and output of pick-up is introduced directly into the broadcasting amplifier from the pick-up. This arrangement avoids losses or distortion from the 20 microphone and also permits. broadcasting even where there is extraneous noise. For such broadcasting the player may wish to hear his playing clearly enough to guide his interpretation and do so without the use'of amonitor speaker oper- 25 ated from the broadcasting station amplifier.

My invention also ofiers mechanical means change-the timbre of the instrument tone throug the pick-up and independently of whatever such possibilities'are offered by the pick-up cdnstruc- 30 tion. Thus, adjusting bolt 36! and lever it alone can put more or less treble string presure on the pick-up armature, adjusting bolt 352 and lever 35 alone can put more or less bass string pressure on the pick-up armature. A corre- 35 sponding variance in timbre of tone will result. This variety of adjustments has the same efiect on the tone as that-mechanically amplified by sound boards 9 and it.

My invention makes possible (1). the use of i0 mechanical amplification only, for string vibration; use of electrical amplification only; or use of both at the same time, (2) the-use of mechanical amplification from two sound boards, forming the top and back of the instrument body, and with or without electrical amplification, (3) mechanical control of timbre of tone from pick-up amplifier-speaker device used with a stringed instrument, from a sound-board type instrument. and from an instrument using both sound board 60 n and electrical amplification for tone production from string vibration, and (4) transferring string pressure from armature bar of pick-up device to two sound boards so that all string pressure available is substantially borne by each board and in 55 a direction to press them outwardly from the instrument body. a

I have illustrated and described my improvements in an embodiment which. I have found very practical. I have not attempted to illustrate or describe other embodiments or adaptations, as it is believed this disclosure will enable those skilled in the art to embody or adapt my improvements as may be desired. A

Having, thus described my invention, what I claim as new and desire to secure by Letters Patent is:'

1. A stringed musical instrument comprising a belly sounding board having a transverse string bridge slot and a transverse back bridge slot, a back sounding board, and a side wall co'acting with said belly and back sounding boards to pro vide a sound box, a transverse drawer mounted on said side wall at opposite sides of said sound box and underlying said string bridge slot, spaced 7 at the ends of the support, a

posts on said drawer, a string bridge support mounted on said posts, an electrical pick-up operatively associated with said support within the sound box and comprising a stator fixed to said drawer and an armature constituted by a free end of said string bridge support, a string bridge mounted on said support to project through and clear of said string bridge slot and having an aperture dividing the lower half of the bridge and provided with allel with the top of the bridge, the bridge and one post being disposed medially of the support, and the stator and the other post being disposed back bridge mounted on said back sounding board and projecting through and clear of said back bridge slot, a pair of treble and bass bridge levers. mounted on said back bridge in side-by-side relation and extending at one end under the upper edge of the aperture in said string bridge, and adjustable bolts connecting the opposite ends of the bridge levers to the belly sounding board for lifting said string bridge relative to its support and at the same time establishing an operative connection between the string bridge and both sounding boards so that the latter are vibrated simultaneously and oppositely relative to each other by the vibration of said string bridge;

2. A stringed musical instrument comprising a belly sounding board having a transverse string bridge slot and a transverse back bridge slot, a back sounding board, and a side wall coacting with said belly and back sounding boards to provide a sound box, a transverse drawer mounted on said side wall atopposlte sides of said sound spaced posts on said drawer, a string bridge support mounted on said posts, an electrical pickup operatively associated with said support within the sound box and comprising a stator fixed to said drawer and an armature constituted by a free end of said bridge support, .a string bridge mounted on said support to project through and clear of said string bridge slot and having an aperture provided with an upper edge parallel with the top of the bridge, the bridge and one post being disposed medially oi the support, and the stator and the other post being disposed at the ends of the support, a back bridge mounted on said back sounding .bo'ard and projecting through and clear of said back bridge slot, bridge levers mounted on said back bridge in side-byside relation and extending at one end under the upper edge of the aperture in said string bridge,

and adjustable means connecting the opposite ends of the bridge levers to the belly sounding board for lifting saitLstring bridge relative to its support and at the sametime establishing an operative connection between the string bridge and both sounding boards so that the latter are vibrated "simultaneously by the vibration of said string bridge.

3. A stringed musical instrument comprising a belly sounding board having a transverse string bridge slot and a transverse back bridge slot, a back sounding board, and a side wall coacting with said belly and back sounding boards to provide a sound box, a transverse support member mounted on said side wall at opposite sides of said sound box, spaced posts on said support member, a string bridge support mounted on said posts, a string bridge mounted on said support to project through said string bridge slot and having anaperture provided with an upper edge parallel with the the bridge andone post being disposed medially of the support, the other post an upper edge parbeing disposed at one end of the support, an electrical pick-up comprising a stator mounted on said support member and an armature consisting of the free end of said support, a back bridge mounted on said back sounding board and projecting through said back bridge slot, a plurality of bridge levers mounted on said back bridge in side-= by-side relation and extending at one end under the upper edge of the aperture in said string bridge, and adjustable tension means connecting the opposite ends of the bridge levers to the belly sounding board for lifting said string bridge rel- 1 ative to its support and at the same time establishing an operative connection between the string bridge and both sounding boards so that the latter are vibrated simultaneously and oppositely relative to each other by the vibration or" said string bridge.

4. A stringed musical instrument comprising a belly sounding board having a transverse slot, a 20 back sounding board, and a side wall coacting with said belly and back sounding boards to provide a sound box, a cross support member mounted on said side wall at opposite sides of said sound box, a string bridge support mounted on said sup- 25 projecting through said slot, a plu 30 meeting the opposite ends of the bridge levers to 35 the belly sounding board, and an electrical pickup comprising a stator and an armature, the string bridge support being formed of magnetic material to constitute said armature-the stator being mounted on said support member under the 40 free end of said armature.

5. A stringed musical instrument comprising a belly sounding board, a back sounding board, and a side wall coacting with said belly and back sounding boards to provide a sound box, a support 45 member mounted on said side wall within said sound box, a string bridge support" mounted at spaced points on said support member, a string bridge mounted on said support, a back bridge mounted on said back sounding board, a plurality 50 of string bridge supporting levers mounted on said back bridge in side-by-side relation, and adjustable means connecting the bridge levers to the belly sounding board for lifting said string bridge relative to its support and at the same time es- 55 tablishing an operative connection between the string bridge and both sounding boards so that the latterare vibrated simultaneously and oppositely relative to each other by the vibration of said string bridge, the string bridge being disso posed medially of said support, the latter having a free end composed of magnetic material, and

an electrical pick-up stator mounted on said support member for coaction with said armature.

6. A stringed musical instrument comprising a 05 belly sounding board, a back sounding board, and a side wall coasting with said belly and back sounding boards to provide a sound box, a string bridge support'in said sound box, a back bridge mounted on said back sounding board, a string 70 bridge supporting lever mounted on said back bridge, adjustable means connecting the bridge leversto the belly sounding board for lifting said string bridge relative to its support and at the same time establishing an operative connection 75 I between the string bridge and both sounding boards so that the latter are vibrated simultaneously by the vibration of said string bridge, means supported by said side wall and acting to support said string bridge support at spaced points, one end of the support comprising the armature of a generator, and a stator fixed to said means for coaction with said armature.

'7. A string musical instrument comprising a belly sounding board having a transverse string bridge slot, a back sounding board, and a side wall coacting with said belly and back sounding boards to provide a. sound box, the side wall having a drawer opening in one side thereof, a. pair of drawer shelves mounted on opposite sides of said side wall on a level with the lower edge of said drawer opening, a drawer disposed on said shelves and having a front panel filling the drawer opening, a pair of spaced blocks mounted on said drawer on one side of its longitudinal center, a string bridge support mounted on said blocks and having a free end overhanging one side of the longitudinal center of said drawer and constituting a pick-up armature, an electrical pick-up comprising said armature and a stator fixed to said drawerpa string bridge disposed on said support and projecting through said slot clear of the belly sounding board, and adjustable lever means associated with said belly and back sounding boards for lifting said string bridge from its support and forming an operative connection between the string bridge and sounding boards.

8. A stringed musical instrument comprising a belly sounding board, having a transverse string bridge slot, a back sounding board, and a sidewall coacting with said belly and back sounding boards to provide a sound'box, the side wall having a drawer opening in one side thereof, a pair of drawer shelves mounted on opposite sides of said side wall on a level with the lower edge of said drawer opening, a drawer disposed on said shelves and having a front panel filling the drawer opening, a pair of spaced blocks mounted on said drawer on one side of its longitudinal center, a string bridge support mounted on said blocks and having a free end overhanging one side of the longitudinal center of said drawer and constituting a pick-up armature, an electrical pick-up comprising said armature and a stator fixed to said drawer, and a string bridge disposed on said support and projecting through said slot clear of the belly sounding board.

9. A stringed musical instrument comprising a belly sounding board having a transverse string bridge slot, a back sounding board, and a side wall coasting with said belly and back sounding boards to provide a sound box, a pair of shelves mounted on opposite sides of said side wall on a level, a beam disposed on said shelves, a pair of spaced blocks mounted on said beam on one. side of its longitudinal center, a string bridge support mounted on said blocks and having a free end overhanging one side of-the longitudinal center of said beam and constituting a pick-up armature, an electrical pick-up comprising said armature and a stator fixed to said beam, a string I bridge disposed on said support and projecting through said slot clear of the belly soun i g board, and adjustable lever means w ciated wi 11 said belly and back sounding boards for lifting said string biidge from its support and forming an operative connection between the string bridge and sounding boards. I

10. A stringed musical instrument comprising a belly sounding board having a transverse strin bridge slot, a side wall coacting with said belly, a pair of shelves mounted on opposite sides of said side wall on a level, a beam disposed on said shelves, a, pair of spaced blocks mounted on said beam on one side of its longitudinal center,- a string bridge support mounted on said blocks and having a free end overhanging one side of the longitudinal center of said beam and constituting a pick-up armature, an electrical pick-up comprising said armature and a stator fixed to said beam, a string bridge disposed on said support and projecting through said slot clear of the belly sounding board, and adjustable means associated with said belly sounding board for lifting said string bridge from its support and to an operative 15 connection between the string bridge and sounding board. 11. A stringed musical instrument comprising a belly sounding board having a transverse string bridge slot, a back sounding board, and a side wall coasting with said belly and back sounding boards to provide a sound box, a string bridge support mounted on said sidewall and having a free end constituting a pick-up armature, anelectrical pick-up comprising said armature and a stator, a string bridge disposed on said support and projecting through said slot clear of the belly sounding board,-and adjustable lever means associated with said belly and back sounding boards for lifting said string bridge from its support and. form-- ing an operative connection between the string bridge and sounding boards.

12. A stringed musical instrument comprising a belly sounding board, a back sounding board, and a side wall coacting with said belly and back sounding boards to provide a sound box, a support Jmember mounted at its ends on said side wall within the sound box, a string bridge support mounted at spaced points on said support member, said support having a free end constituting an I armature, an electrical pick-up comprising said armature and a stator mounted on said support member, a string bridge disposed on said support clear of the belly sounding board, and adjustable means associated with said belly and' back sounding boards for lifting said string bridge from its support and forming an operative connection between the string bridge and sounding boards.

13. A stringed musical instrument comprising a sounding board, a side wall, a support member mounted at its ends on said side wall within the sound box, a string bridge support mounted at spaced points on said support member, said support having a. free end constituting an armature,

a string bridge disposed on said support clear of the sounding board, and adjustable means for lifting said string bridge from its support and forming an operative connection between the string bridge and sounding board.

14. The combination in a stringed musical instrument, of a body comprising front and rear sounding boards; the front sounding board having-spaced bridge openings therein, a rear sounding board bridge mounted on the rear sounding board and disposed through one of said openings es gen ers a side relation, and independently adjustable threaded tension members connecting the ends of said levers opposite the string bridge with the front sounding board.

15. The combination in a stringed musical in strument, of a body comprising front and rear sounding boards, the front sounding board having spaced bridge openings therein, a rear sounding board bridge mounted on the rear sounding board and disposed through one of said openings in said front sounding board, a string bridge disposed through the other opening in said front sounding board, an electrical pick-up device comprising an armature adapted to sustain the thrust of said string bridge, means supporting said armature medially and at one end thereof, and a stator carried by said means for coaction with the free end of said armature, a pair of string bridge supporting levers fulcrumed on said rear sounding board bridge, and independently adjustable members connecting the ends of said levers opposite the string bridge with the front sounding board.

16. The combination in a stringed musical in= strument, of a body comprising front and rear sounding boards, a rear sounding board bridge mounted on the rear sounding board and dis posed through an opening in said front sounding board, a string bridge disposed through an open ing in said front sounding board, an electrical pick-up device comprising an armature operatively associated with said string bridge, means supporting said armature medially and at one end thereof, and a stator carried by said means for coaction with the free end of said armature,- a pair of string bridge supporting levers fulcrumed on said rear sounding board bridge, and independently adjustable threaded members connecting said levers with the front sounding board.

1'7. The combination in a stringed musical instrument, of a body comprising front and rear sounding boards, a rear sounding board bridge mounted on the rear sounding board and disposed through an opening in said front sounding board, a string bridge, a pair of string bridge supporting levers fulcrumed on said rear sounding board bridge, and independently adjustable threaded members connecting said levers with the front sounding board, said threaded members and said string bridge being connected to opposite sides of said levers relative to said rear sounding board bridge.

18. The combination in a stringed musical instrument, or a body comprising front and rear sounding boards, a rear sounding board bridge mounted on the rear sounding board and disposed through an opening in said front sounding board, a string bridge disposed through an opening in said front sounding board, an electrical pick-up device comprising an armature operatively associated with said string bridge, means supporting said armature mediallyiand at one end thereof, and a stator carried by said means for coaction with the free end of said armature, a pair of string bridge supporting levers fulcrumed on said rear sounding board bridge, and independently adjustable means connecting said levers with the front sounding board.

19. The combination'in a stringed musical instrument, of a body comprising front and rear sounding boards, a rear sounding board bridge mounted on the rear sounding board and disposed through an opening in said front sounding board, 5 a string bridge, a pair of string bridge supporting levers fulcrumed on said rear sounding board bridge, and independently adjustable means connecting said levers with the front sounding board, said last named means and said threaded memin hers and said string bridge being connected to opposite sides of said levers relative to said rear sounding board bridge.

20. The combination in a stringed musical instrument, of a body comprising front and rear 15 sounding boards, a rear sounding board bridge mounted on the rear sounding board and disposed through said front sounding board, a string bridge disposed through an opening in said front sounding board, an electrical pick-up device comprising an armature adapted to sustain the thrust of said string bridge, means supporting said armature medially and at one end thereof, and a stator carried by said means for coaction with the free end of said armature, a string bridge 25 supporting lever fulcrumed on said rear sounding board bridge, and a threaded member connecting said lever with the front sounding board.

21. The combination in a stringed musical in strument, of a body comprising front and rear sounding boards, a rear sounding board bridge mounted on the rear sounding board and disposed through said front sounding board, a string bridge, an electrical pick-up device comprisingan armature adapted to sustain the thrust of said string bridge, means supporting said armature medially and at one end thereof, and a stator carried by said means for coaction with the free end of said armature, a string bridge supporting lever fulcrumed on said rear sounding board 40 bridge, and a threaded member connecting said lever with the front sounding board.

22. The combination in a stringed musical instrument, of a body comprising front and rear sounding boards, a rear sounding board bridge 45 mounted onthe rear sounding board and disposed through said front sounding board, a string bridge disposed through an opening in said front sounding board, an electrical pick-up device comprising an armature adapted to sustain the thrust 0 of said string bridge, means supporting said armature medially and at one end thereof, and a stator carried by said means for coaction with i the free end of said armature, a string bridge supporting lever fulcrumed on said rear sound- 55 ing board bridge, and an adjustable member con- 1 necting said lever with the front sounding board.