CA1160081A - Multiple bridge for stringed instruments - Google Patents
Multiple bridge for stringed instrumentsInfo
- Publication number
- CA1160081A CA1160081A CA000384350A CA384350A CA1160081A CA 1160081 A CA1160081 A CA 1160081A CA 000384350 A CA000384350 A CA 000384350A CA 384350 A CA384350 A CA 384350A CA 1160081 A CA1160081 A CA 1160081A
- Authority
- CA
- Canada
- Prior art keywords
- string
- panel
- resonating
- bridge
- resonating panel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10D—STRINGED MUSICAL INSTRUMENTS; WIND MUSICAL INSTRUMENTS; ACCORDIONS OR CONCERTINAS; PERCUSSION MUSICAL INSTRUMENTS; AEOLIAN HARPS; SINGING-FLAME MUSICAL INSTRUMENTS; MUSICAL INSTRUMENTS NOT OTHERWISE PROVIDED FOR
- G10D3/00—Details of, or accessories for, stringed musical instruments, e.g. slide-bars
- G10D3/04—Bridges
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- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Multimedia (AREA)
- Stringed Musical Instruments (AREA)
Abstract
Abstract A string supporting bridge arrangement for a stringed musical instrument comprises multiple bridges. Where the bridge arrangement is installed in a stringed musical instrument having a top and bottom resonating panel, one bridge serves to directly transmit vibrations of the strings to the top resonating panel and one bridge serves to directly transmit vibrations to the bottom resonating panel so that the two panels vibrate in opposite direction to each other.
Description
This inven~on xelates to a st:ring-supporting bridge arrangement for a s-tringed musical instrument. More particularly, this invention relates to a multiple bridge arrangement.
Stringed instruments such as guitar~, banjos, violins and the like have a sound box or resonance body which resonates in response to the vibrations of the strings. Such a resonance body generally comprises a top resonating panel and a bottom resonating panel. A
string-supporting bridge mounted on the top panel connects the strings to the top panel so that the latter resonates in accordance with the vibration of the strings. The quality of the musical sound o~ an instrument depends on the manner in which the vibrations are transferred from the strings to the resonance body.
Various approaches have been taken in order to increase the sound quality of an instrument. In violins sound posts have been installed in close proximity to the string-supporting bridge. The sound posts connect the top and bottom panels, thus causing the bottom panels to vibrate in unison and parallel with the top panel. However, adjacent ~he points of connection between the sound posts and each o~ thepanels vibrational movement of the panels is reduced to almost zero. Representative of devices of this kind are the sound posts described in U.S. Patent
Stringed instruments such as guitar~, banjos, violins and the like have a sound box or resonance body which resonates in response to the vibrations of the strings. Such a resonance body generally comprises a top resonating panel and a bottom resonating panel. A
string-supporting bridge mounted on the top panel connects the strings to the top panel so that the latter resonates in accordance with the vibration of the strings. The quality of the musical sound o~ an instrument depends on the manner in which the vibrations are transferred from the strings to the resonance body.
Various approaches have been taken in order to increase the sound quality of an instrument. In violins sound posts have been installed in close proximity to the string-supporting bridge. The sound posts connect the top and bottom panels, thus causing the bottom panels to vibrate in unison and parallel with the top panel. However, adjacent ~he points of connection between the sound posts and each o~ thepanels vibrational movement of the panels is reduced to almost zero. Representative of devices of this kind are the sound posts described in U.S. Patent
2,141,735 to Borg, U.S. Patent 2,162,595 to Virzi, U.SO
Patent 3,678,794 to Tansky and U.S. Patent 4J206,67B to Guerrero.
It has also been suggested to use a lever arrangement to transfer the vibrations from the s~ring- supporting bridge to the top and bottom pa,nels. In such an arrangement the string_supporting bridge is not mounted on the top panel but rather on a lever. The lever is pivotally movable between an upper member which is connec1:ed to the top panel and a lower member which is c~nnected to the bott~m panel. When the strings are played, the vibrations are transmitted from the bridge to the lever which extends substantially perpendicular to the string supporting bridge. The vibrations are then transferred along the lever to the upper and lower members which in turn cause the top and bottom panels, respectively, to vibrate. With such an arrangement the two panels are caused to vibrate in opposite directions. However, due to the relatively long distance the vibrations have to travel until they reach the top and bottom panels some of the intensity and volume of sound is being 105t. Known lever arrangements of this type are described in Canadian patents 360,682 and 373,008 to Loar.
OO~
In one aspect of the present invention there is provided a bridge arrangement for a stringed musical instrument having a neck, a resonance body including a top resonating panel and a bottom resonating panel, and a plurality of string means extending along the neck and the top panel. The bridge arrangement comprises:
(a) a first bridge means adapted to be in contact with the string means and secured to the top resonating panel, and (b) a second bridge means adapted to be in contact with the string means and secured to the bottom resonating panel. The first bridge means, when mounted on a musical instrument, transfers vibration directly from said striny means to said top resonating panel and said second bridge means, when mounted on a musical instrumenk, transfers vibration directly from said string means to said bottom resonating panel.
In a typical embodLment ofthe invention the second bridge means is adapted to extend through a slot in the top resonating panel without contacting the top resonating panel and through the resonance body ko the bottom resonating panel and to be fixedly secured to the b~ottom resonating panelO
In a preferred embodiment of the invention the first ~ridge means comprises first string oontacina ~eans and at least one post adapted to connect the first string oontacing means with the top resonating panel and the second bridge means comprises second 5trillg o~nta~ing ~e~ and at least one post connected thereto. This post is adapted to extend through the slot in the top resonating panel without contacting the top resonating panel and through the resonance body to the bottom resonating panel and to be fixedly secured to the bottom resonating panel. The length of ~ach o~ the posts is adjustable.
Preferably either the first or the second string contacting means is provided with a plurality of spaced apart openings or l~er recesses facmg, when the bridge neans is ~unted on a musical instrument, the top resonating panel. The other of the two string contacting means is provided with a plurality of spaced apart openings or ~xr recesses located on a portion of the string contacting means remot~ from the top resonating panel. The openings and recesses, respectivelyj are adapted to receive the string means.
In a further aspect o~ th~ present invention there is provided a stringed musical instxument comprising:
(a) a resonance body including a neck, frame means, a top resonating panel and a bottom resonating panel, each panel being mounted on the frame means, (b) string means extending along the neck and the top resonating panel to provide a source of sound vibration, and ~ c) a bridge arrangement including a first bridge means in contact with the string means and secured to the top resonating panel, and a second bridge means in contact with the string means and secured to said bottom r~sonating panel.
_ 5 ~
The ~irst bridge means transfers vibration directly from said string means to said top resonating panel and the second bridge means transfPrs vibration directly from said string means to said bottom resonating panel.
In a typical emxx~Dt of this aspect of ~he invention a plurality of spaced apart reinforcement ribs extend ~enerally in the direction of the string means along the inside of the top resonating panel and along the bottom resonating panel.
In a preferred embodiment of the invention the first bridge means comprises first string contacting means and at least one post which is secured to the top resonating panel and to at least one of the reinforcement ribs on the inside of the top resonating panel. The second bridge means comprises second string contacting means and at least one post connected thereto. The post extends through the slot in the top resonating panel without contacting the top resonating panel and through the resonance body to one of said reinforcement ribs on the inside of the bottom resonating panel and is fixedly secured to the reinforcement rib.
The first bridge means may be located closer to the neck of the instrument than the second bridge means or vice versa. The string contacting means of one of the two bridge means is generally provided either with a plurality of spaced apart openings or a plurality of recesses facing the top resonatLng panel (lower reoesses) and the string contacting means of the other bridge means is generally provided either with a plurality of spaced apart openings or a plurality of recesses located in the portion of the string contacting means which is remote from the top resonating panel (upper recesses). The recesses and openings, respectively, receive the string means. One of the two string contacting means holds the string means down in the direction of the top resonating panel and the other string contacting means holds the string means away from the top resonating panel.
In a preferred embodiment the first bridge means is located closer to the neck of the instrument than the second bridge means. The first string contacting means is provided with a plurality of spaced apart recesses located in the portion facing the top resonance panel and the second string contacting means is provided with a plurality of spaced apart openings. The distances between the recesses and t~e top resonating panel and between the openings and the top resonating panel are adjusted such that the string means has the desired tension and exerts the desired pressure or load on the bridge means and resonating panels. The string means exerts on the first string contacting means and, thus, on the first bridge means a sli~ht upward pressure in the direction away from the top resonating panel and on the second string contacting means and, thus, on the second bridge means a slight down-ward pressure in direction of the top resonating panel.
The stringed musical instr~ent accoxdin~ to the invention opexates in the following way:
(~) When a player picks or plucks a string in an instrument in which the bridge means located closer to the neck of the instrument ~olds the strings down in direction of the top resonating panel ~bridge A) and the bridge means located more remote from the neck of the instrument holds the strings up away from the top resonating panel (bridge B), the increased tension of the strings urges bridge A momentarily outwards and bridge B ;nwards starting off a vibrational movement.
~. ~ ~ 081 Independent of whether bridge A is a first bridge means connected to the top resonating panel and bridge B is a second bridge means connected to the bottom resonating panel or whether bridge A is connected to the bottom and bridge B
is connected to the top resonating panel the mo~E~t of bridges A and B
results in the top resonating panel being urged outwardly in upward direction and the bottom resonating panel being pushed outwardly in ~ward directian. I~his'move~ent is, of o~urse, followed by an inward movement of both resonating panels towards each other, etc.
(b) When a player picks or plucks a string in an instrument in which the bridge means located closer to th~
neck of the instrument holds the strings up away from the top resonating panel ~bridge B) and the bridge means located more remote from the neck of the instrument holds the strings down in direction of the top resonating panel (bridg~ A)l the increased tension of the string urges bridge B inwards and bridge A outwards.
This movement of bridges A and B results in the top resonating panel being pushed inwardly in downward direction and the bottom resonating panel being pushed inwardly in upward direction, independent of whether bridge A is connected to the top resonating panel and bridge B to the bottom resonating panel or vice versa.
The inward movement of the two resonating panels is, of course, followed by an outward movement, etc.
In either arrangement o~ the bridge means picking or plucking a string results in the top and bottom resonating panels vibrating simultaneously in opposite direction to each other. In this tlay thc 'vibration5 arc t^ansfcrrcc' c'ircctly n~t onlv to thc top resonating ~ancl but also to thc bottom resonating panel.
- 8 ~ 8~
In conventional instruments having one string-supporting bridge connected to the top resonating panel vibrations are transmitted directly only to the top resonating panel. Thus, only secondary vibrations reach the bottom resonating panel. As a consequence the bottom resonating panel does not always vibrate in the proper phase relative to the top panel as is desirable to achieve optimal sound quality. Additionally, the amplitude of the vibration of the bottom panel in such conventional instruments is generally smaller than in instruments in which the vibration is directly transferred to the bottom panel. This results in reduced sound volume.
In a preferred embodiment of the invention each of the two bridge means comprise string contacting mean~ connected to at least one post which is secured to the top or bottom panel, respectively.
As longidutinal compression waves travel fast, such posts ensure a) that the vibration of th~ string is transferred rapidly to both panels allowing fast and sharp response and b) tha~ the vibration is transmitted to top and bottom panels substantially simultaneously causing the two panels to start vibrating practically simultaneously and in phase in opposite direction to each other. This ensures optimal sound intensity, sharpness and volume.
In lever arrangements such as the one described in Canadian Patents 360,682 and 373,008 the distances which the vibration has to travel to reach the top and bottom panels are considerably longer than in the multiple bridge arrangement according to the invention.
As transverse compression waves do not travel as fast in wood as long-itudinal compression waves, the lever arrangement does not react as im-mediately to changes in the vibra~ion of the string as the present bridge arrangement. Consequently, the sound of an instrument with such lever arrangement tends to ~e less intense and sharp~han that of a~
instrument with the present bridye arrangement.
The present invention will now be described in more detail with reference to the accompanying drawings which illustrate, by way of example, one preferred embodiment of the invention and in which:
FIGURE 1 is a schematic side elevation of a stringed musical instrument provided with a dual bxidge arrangement a¢cording to a preferred embodiment of the invention;
FIGURE 2 is a longitudinal sectional view of the resonance body of the instrument of Eigure l;
FIGURE 3 is a cxoss-sectional view of the resonance body along the line III-III in Figure l;
FIGURE 4 is a oross-sectional view of the resonance body along line IV-rV in Figure l;
FIGURE 5A ~o C are diagrammatic ~artial longitudinal sectional views of the resonance body of the instrument of Figure 1 showing the movement of the dual ~ridge arrangement and top and bottom resonating panels in response to movement.
of the strings; and Figures 6A to D are diagrammatic partial longitudinal sectional views of resonance bodies illustrating several preferred ways in which the ~wo bridge means of a dual bridge arrangement according to the invention can be positioned relative to each other.
Referring to the drawings Figure 1 shows a stringed musical instrument such as a banjo or the like c~mprising a resonance body 10, a neck 11 and a head 120 Strings 15 - 10~
extend from the head 12 to anchors or to the tailpiece 18 across a dual bridge arrangement consisting of a first bridge 20 and a second bridge 30. The resonance body 10 has a top resonating panel 13 and a bottom resonating panel 14. As shown in Figures 2 to 4 the two resonating panels 13 and 14 may be reinforced by a plurality of reinforcement ribs 40.
Such ribs may be glued or otherwise attached to the respective panel.
In the preferred embodiment shown in Figures 2 to 4 the first bridge 20 consists of a string contacting means or cross-bar 21 and two posts which oonnect cross-bar 21 to ~e top resonating panel 13. The posts may consist of screws or screw-threaded ~olts 22 which each have a head 23. Each bolt passes slidingly through a respective opening 26 in cross-bar - 21 and is screwed to panel 13 at a point where panel 13 is supported by a reinforcement rib 40. Heads 23 are located in corresponding recesses 25 in cross-bar 21. On the side of cross-bar 21 which faces panel 13 a plurality of recesses 28 are located. The number of recesses 28 corresponds to the number of strings 15 of the instrument. The tension of the strings passing through recesses 28 causes cross-bar 21 to bPar against heads 23. The distance b~tween cross-bar 21 and panel 13 may be adjusted by tightening or loosening bolts 22. Optionally, cross-bar 21 may be connected to panel 13 ; with only one post or with three or more posts.
The second bridge 30 consists of a string contacting means or cross-bar 31 and two posts. Each post ex~s through a respective slot or op~ng 17 in panel 13 and clear of the opening to panel 14. The 1].
posts can consist of a screw-threaded bolt 32 which may be screwed into a dowel 34 which, in turn, may be attached to a block 37.
For example, dowel 34 may be glued into a recess in block 37.
Each bolt 32 passes slidingly through a respective opening 36 in cross-bar 31 and is provided with adjustment means such as an adjustment nut 33 Each block 36 is fastened to panel 14 at a point where the panel is supported by a reinforcement rib 40. In cross-bar 31 a plurality of holes 38 are located, the number of holes 38 corresponding to the number of strings 15 of the instrument. The tension of the strings passing ~hrough the holes 38 causes cross-bar 31 to bear against nuts 33. The distance between cross-bar 31 and panel 14 may be adjusted with nuts 33. Cross-bar 31 may, alternatively, be connected to panel 13 with only one post ~r with three or more posts.
Optionally, opening 17 in panel 13 may be lined with material such as felt.
When a player plucks or picks the instrument the strings staxt vibrating and the ~ension of the strings is momentarily increased. The vibration is transmitted to first and second bridge means 20 and 30 and from there ~o the top and bottom resonating panels 13 and 14, respecti~ely.
Figure 5 illustrates the transfer of vibration diagrammatically.
For reasons of illustration the vibrational movement is shown greatly exaggerated. Diagram A shows the string supporting bridge arrangement according to a preferred embodiment of the invention in resting position. Diagram B shows the bridge arrangement immediately after string 15 has been picked or plucked. The tension of the string i 12~
increases and bears on bridges 20 and 30, urging cross-bar 21 upwardly and, simultaneously, cross-bar 31 downwardly.
This, in turn, causes top resonating panel 13 to be lifted upwardly via post 51 and bottom resonating panel 14 to be pushed downwardly via post 52. In the return movement the two resonating panels swing :inwardly as shown in diagram C~thus vibrating between positions B and C. Following release of the tension of the string, panels 13 and 14 return to their resting position (as shown in diagram A).
In this way, the vibration of the string is transmitted simultaneously via cross-bar 21 to post 51 and to panel 13 and ~ia cross-bar 31 to post 52 and to panel 14 causing the two panels to start resonating practically simultaneous~y in opposite directions to each other, thereby increasing the sound, volume and intensity of the instrument.
Figure 6 shows various preferred ways in which the two bridge means 20 and 30' can be arranged relative to each other to form a string supporting bridge arrangement according to the invention. All four diagrams in Figure 6 show the bridge arrangement in resting position. In diagrams A and B bridge 20 is located closer to the neck of the instrument than bridge 30', and in diagram C and B
bridge 30' is located closer to the neck. In diagrams A and C the string conducting means or cross bar 21 of bridge 20 is provided with lower recesses as illustrated in the embodiment shown in Figure 3 and the string contacting means or cross-bar 31' of bridge 30' is provided with upper recesses. In diagrams B and C string contacting . - 13 ~
means 21 is provided with upper recesses and string contacting means 31' with lower recesses. In each case the loading or pressure exerted by the strings on the top and bottom resonating panels 13 and 14 via the two bridges can be adjusted by adjusting the length of the posts 51 and/or 52. In arrangements A and D the strings in resting position exert a slight pressure in upward direction on bridge 20 and in downward direction on bridge 30'. Consequently, when a string is picked or plucked the increased tension of the string causes bridge 20 to be urged upwardly and bridge 30' to be urged downwardly resulting in outward movement of both resonating panels followed by a return movement of the panels in inward direction and so on.
In arrangements B and C, on the other hand, the strings exert a slight pressure in upward direction on bridge 30' and in downward direction on bridge 20 so that, when the instrument is played, the increased tension of the string causes bridge 30' to be urged upwardly and bridge 20 to be urged downwardly resulting in inward movement of both resonating panelsq Thus, in all four arrangements picking or plucking a string causes the two panels to start resonating partically simultaneously in opposite directions to each other.
Patent 3,678,794 to Tansky and U.S. Patent 4J206,67B to Guerrero.
It has also been suggested to use a lever arrangement to transfer the vibrations from the s~ring- supporting bridge to the top and bottom pa,nels. In such an arrangement the string_supporting bridge is not mounted on the top panel but rather on a lever. The lever is pivotally movable between an upper member which is connec1:ed to the top panel and a lower member which is c~nnected to the bott~m panel. When the strings are played, the vibrations are transmitted from the bridge to the lever which extends substantially perpendicular to the string supporting bridge. The vibrations are then transferred along the lever to the upper and lower members which in turn cause the top and bottom panels, respectively, to vibrate. With such an arrangement the two panels are caused to vibrate in opposite directions. However, due to the relatively long distance the vibrations have to travel until they reach the top and bottom panels some of the intensity and volume of sound is being 105t. Known lever arrangements of this type are described in Canadian patents 360,682 and 373,008 to Loar.
OO~
In one aspect of the present invention there is provided a bridge arrangement for a stringed musical instrument having a neck, a resonance body including a top resonating panel and a bottom resonating panel, and a plurality of string means extending along the neck and the top panel. The bridge arrangement comprises:
(a) a first bridge means adapted to be in contact with the string means and secured to the top resonating panel, and (b) a second bridge means adapted to be in contact with the string means and secured to the bottom resonating panel. The first bridge means, when mounted on a musical instrument, transfers vibration directly from said striny means to said top resonating panel and said second bridge means, when mounted on a musical instrumenk, transfers vibration directly from said string means to said bottom resonating panel.
In a typical embodLment ofthe invention the second bridge means is adapted to extend through a slot in the top resonating panel without contacting the top resonating panel and through the resonance body ko the bottom resonating panel and to be fixedly secured to the b~ottom resonating panelO
In a preferred embodiment of the invention the first ~ridge means comprises first string oontacina ~eans and at least one post adapted to connect the first string oontacing means with the top resonating panel and the second bridge means comprises second 5trillg o~nta~ing ~e~ and at least one post connected thereto. This post is adapted to extend through the slot in the top resonating panel without contacting the top resonating panel and through the resonance body to the bottom resonating panel and to be fixedly secured to the bottom resonating panel. The length of ~ach o~ the posts is adjustable.
Preferably either the first or the second string contacting means is provided with a plurality of spaced apart openings or l~er recesses facmg, when the bridge neans is ~unted on a musical instrument, the top resonating panel. The other of the two string contacting means is provided with a plurality of spaced apart openings or ~xr recesses located on a portion of the string contacting means remot~ from the top resonating panel. The openings and recesses, respectivelyj are adapted to receive the string means.
In a further aspect o~ th~ present invention there is provided a stringed musical instxument comprising:
(a) a resonance body including a neck, frame means, a top resonating panel and a bottom resonating panel, each panel being mounted on the frame means, (b) string means extending along the neck and the top resonating panel to provide a source of sound vibration, and ~ c) a bridge arrangement including a first bridge means in contact with the string means and secured to the top resonating panel, and a second bridge means in contact with the string means and secured to said bottom r~sonating panel.
_ 5 ~
The ~irst bridge means transfers vibration directly from said string means to said top resonating panel and the second bridge means transfPrs vibration directly from said string means to said bottom resonating panel.
In a typical emxx~Dt of this aspect of ~he invention a plurality of spaced apart reinforcement ribs extend ~enerally in the direction of the string means along the inside of the top resonating panel and along the bottom resonating panel.
In a preferred embodiment of the invention the first bridge means comprises first string contacting means and at least one post which is secured to the top resonating panel and to at least one of the reinforcement ribs on the inside of the top resonating panel. The second bridge means comprises second string contacting means and at least one post connected thereto. The post extends through the slot in the top resonating panel without contacting the top resonating panel and through the resonance body to one of said reinforcement ribs on the inside of the bottom resonating panel and is fixedly secured to the reinforcement rib.
The first bridge means may be located closer to the neck of the instrument than the second bridge means or vice versa. The string contacting means of one of the two bridge means is generally provided either with a plurality of spaced apart openings or a plurality of recesses facing the top resonatLng panel (lower reoesses) and the string contacting means of the other bridge means is generally provided either with a plurality of spaced apart openings or a plurality of recesses located in the portion of the string contacting means which is remote from the top resonating panel (upper recesses). The recesses and openings, respectively, receive the string means. One of the two string contacting means holds the string means down in the direction of the top resonating panel and the other string contacting means holds the string means away from the top resonating panel.
In a preferred embodiment the first bridge means is located closer to the neck of the instrument than the second bridge means. The first string contacting means is provided with a plurality of spaced apart recesses located in the portion facing the top resonance panel and the second string contacting means is provided with a plurality of spaced apart openings. The distances between the recesses and t~e top resonating panel and between the openings and the top resonating panel are adjusted such that the string means has the desired tension and exerts the desired pressure or load on the bridge means and resonating panels. The string means exerts on the first string contacting means and, thus, on the first bridge means a sli~ht upward pressure in the direction away from the top resonating panel and on the second string contacting means and, thus, on the second bridge means a slight down-ward pressure in direction of the top resonating panel.
The stringed musical instr~ent accoxdin~ to the invention opexates in the following way:
(~) When a player picks or plucks a string in an instrument in which the bridge means located closer to the neck of the instrument ~olds the strings down in direction of the top resonating panel ~bridge A) and the bridge means located more remote from the neck of the instrument holds the strings up away from the top resonating panel (bridge B), the increased tension of the strings urges bridge A momentarily outwards and bridge B ;nwards starting off a vibrational movement.
~. ~ ~ 081 Independent of whether bridge A is a first bridge means connected to the top resonating panel and bridge B is a second bridge means connected to the bottom resonating panel or whether bridge A is connected to the bottom and bridge B
is connected to the top resonating panel the mo~E~t of bridges A and B
results in the top resonating panel being urged outwardly in upward direction and the bottom resonating panel being pushed outwardly in ~ward directian. I~his'move~ent is, of o~urse, followed by an inward movement of both resonating panels towards each other, etc.
(b) When a player picks or plucks a string in an instrument in which the bridge means located closer to th~
neck of the instrument holds the strings up away from the top resonating panel ~bridge B) and the bridge means located more remote from the neck of the instrument holds the strings down in direction of the top resonating panel (bridg~ A)l the increased tension of the string urges bridge B inwards and bridge A outwards.
This movement of bridges A and B results in the top resonating panel being pushed inwardly in downward direction and the bottom resonating panel being pushed inwardly in upward direction, independent of whether bridge A is connected to the top resonating panel and bridge B to the bottom resonating panel or vice versa.
The inward movement of the two resonating panels is, of course, followed by an outward movement, etc.
In either arrangement o~ the bridge means picking or plucking a string results in the top and bottom resonating panels vibrating simultaneously in opposite direction to each other. In this tlay thc 'vibration5 arc t^ansfcrrcc' c'ircctly n~t onlv to thc top resonating ~ancl but also to thc bottom resonating panel.
- 8 ~ 8~
In conventional instruments having one string-supporting bridge connected to the top resonating panel vibrations are transmitted directly only to the top resonating panel. Thus, only secondary vibrations reach the bottom resonating panel. As a consequence the bottom resonating panel does not always vibrate in the proper phase relative to the top panel as is desirable to achieve optimal sound quality. Additionally, the amplitude of the vibration of the bottom panel in such conventional instruments is generally smaller than in instruments in which the vibration is directly transferred to the bottom panel. This results in reduced sound volume.
In a preferred embodiment of the invention each of the two bridge means comprise string contacting mean~ connected to at least one post which is secured to the top or bottom panel, respectively.
As longidutinal compression waves travel fast, such posts ensure a) that the vibration of th~ string is transferred rapidly to both panels allowing fast and sharp response and b) tha~ the vibration is transmitted to top and bottom panels substantially simultaneously causing the two panels to start vibrating practically simultaneously and in phase in opposite direction to each other. This ensures optimal sound intensity, sharpness and volume.
In lever arrangements such as the one described in Canadian Patents 360,682 and 373,008 the distances which the vibration has to travel to reach the top and bottom panels are considerably longer than in the multiple bridge arrangement according to the invention.
As transverse compression waves do not travel as fast in wood as long-itudinal compression waves, the lever arrangement does not react as im-mediately to changes in the vibra~ion of the string as the present bridge arrangement. Consequently, the sound of an instrument with such lever arrangement tends to ~e less intense and sharp~han that of a~
instrument with the present bridye arrangement.
The present invention will now be described in more detail with reference to the accompanying drawings which illustrate, by way of example, one preferred embodiment of the invention and in which:
FIGURE 1 is a schematic side elevation of a stringed musical instrument provided with a dual bxidge arrangement a¢cording to a preferred embodiment of the invention;
FIGURE 2 is a longitudinal sectional view of the resonance body of the instrument of Eigure l;
FIGURE 3 is a cxoss-sectional view of the resonance body along the line III-III in Figure l;
FIGURE 4 is a oross-sectional view of the resonance body along line IV-rV in Figure l;
FIGURE 5A ~o C are diagrammatic ~artial longitudinal sectional views of the resonance body of the instrument of Figure 1 showing the movement of the dual ~ridge arrangement and top and bottom resonating panels in response to movement.
of the strings; and Figures 6A to D are diagrammatic partial longitudinal sectional views of resonance bodies illustrating several preferred ways in which the ~wo bridge means of a dual bridge arrangement according to the invention can be positioned relative to each other.
Referring to the drawings Figure 1 shows a stringed musical instrument such as a banjo or the like c~mprising a resonance body 10, a neck 11 and a head 120 Strings 15 - 10~
extend from the head 12 to anchors or to the tailpiece 18 across a dual bridge arrangement consisting of a first bridge 20 and a second bridge 30. The resonance body 10 has a top resonating panel 13 and a bottom resonating panel 14. As shown in Figures 2 to 4 the two resonating panels 13 and 14 may be reinforced by a plurality of reinforcement ribs 40.
Such ribs may be glued or otherwise attached to the respective panel.
In the preferred embodiment shown in Figures 2 to 4 the first bridge 20 consists of a string contacting means or cross-bar 21 and two posts which oonnect cross-bar 21 to ~e top resonating panel 13. The posts may consist of screws or screw-threaded ~olts 22 which each have a head 23. Each bolt passes slidingly through a respective opening 26 in cross-bar - 21 and is screwed to panel 13 at a point where panel 13 is supported by a reinforcement rib 40. Heads 23 are located in corresponding recesses 25 in cross-bar 21. On the side of cross-bar 21 which faces panel 13 a plurality of recesses 28 are located. The number of recesses 28 corresponds to the number of strings 15 of the instrument. The tension of the strings passing through recesses 28 causes cross-bar 21 to bPar against heads 23. The distance b~tween cross-bar 21 and panel 13 may be adjusted by tightening or loosening bolts 22. Optionally, cross-bar 21 may be connected to panel 13 ; with only one post or with three or more posts.
The second bridge 30 consists of a string contacting means or cross-bar 31 and two posts. Each post ex~s through a respective slot or op~ng 17 in panel 13 and clear of the opening to panel 14. The 1].
posts can consist of a screw-threaded bolt 32 which may be screwed into a dowel 34 which, in turn, may be attached to a block 37.
For example, dowel 34 may be glued into a recess in block 37.
Each bolt 32 passes slidingly through a respective opening 36 in cross-bar 31 and is provided with adjustment means such as an adjustment nut 33 Each block 36 is fastened to panel 14 at a point where the panel is supported by a reinforcement rib 40. In cross-bar 31 a plurality of holes 38 are located, the number of holes 38 corresponding to the number of strings 15 of the instrument. The tension of the strings passing ~hrough the holes 38 causes cross-bar 31 to bear against nuts 33. The distance between cross-bar 31 and panel 14 may be adjusted with nuts 33. Cross-bar 31 may, alternatively, be connected to panel 13 with only one post ~r with three or more posts.
Optionally, opening 17 in panel 13 may be lined with material such as felt.
When a player plucks or picks the instrument the strings staxt vibrating and the ~ension of the strings is momentarily increased. The vibration is transmitted to first and second bridge means 20 and 30 and from there ~o the top and bottom resonating panels 13 and 14, respecti~ely.
Figure 5 illustrates the transfer of vibration diagrammatically.
For reasons of illustration the vibrational movement is shown greatly exaggerated. Diagram A shows the string supporting bridge arrangement according to a preferred embodiment of the invention in resting position. Diagram B shows the bridge arrangement immediately after string 15 has been picked or plucked. The tension of the string i 12~
increases and bears on bridges 20 and 30, urging cross-bar 21 upwardly and, simultaneously, cross-bar 31 downwardly.
This, in turn, causes top resonating panel 13 to be lifted upwardly via post 51 and bottom resonating panel 14 to be pushed downwardly via post 52. In the return movement the two resonating panels swing :inwardly as shown in diagram C~thus vibrating between positions B and C. Following release of the tension of the string, panels 13 and 14 return to their resting position (as shown in diagram A).
In this way, the vibration of the string is transmitted simultaneously via cross-bar 21 to post 51 and to panel 13 and ~ia cross-bar 31 to post 52 and to panel 14 causing the two panels to start resonating practically simultaneous~y in opposite directions to each other, thereby increasing the sound, volume and intensity of the instrument.
Figure 6 shows various preferred ways in which the two bridge means 20 and 30' can be arranged relative to each other to form a string supporting bridge arrangement according to the invention. All four diagrams in Figure 6 show the bridge arrangement in resting position. In diagrams A and B bridge 20 is located closer to the neck of the instrument than bridge 30', and in diagram C and B
bridge 30' is located closer to the neck. In diagrams A and C the string conducting means or cross bar 21 of bridge 20 is provided with lower recesses as illustrated in the embodiment shown in Figure 3 and the string contacting means or cross-bar 31' of bridge 30' is provided with upper recesses. In diagrams B and C string contacting . - 13 ~
means 21 is provided with upper recesses and string contacting means 31' with lower recesses. In each case the loading or pressure exerted by the strings on the top and bottom resonating panels 13 and 14 via the two bridges can be adjusted by adjusting the length of the posts 51 and/or 52. In arrangements A and D the strings in resting position exert a slight pressure in upward direction on bridge 20 and in downward direction on bridge 30'. Consequently, when a string is picked or plucked the increased tension of the string causes bridge 20 to be urged upwardly and bridge 30' to be urged downwardly resulting in outward movement of both resonating panels followed by a return movement of the panels in inward direction and so on.
In arrangements B and C, on the other hand, the strings exert a slight pressure in upward direction on bridge 30' and in downward direction on bridge 20 so that, when the instrument is played, the increased tension of the string causes bridge 30' to be urged upwardly and bridge 20 to be urged downwardly resulting in inward movement of both resonating panelsq Thus, in all four arrangements picking or plucking a string causes the two panels to start resonating partically simultaneously in opposite directions to each other.
Claims (20)
1. A bridge arrangement for a stringed musical instrument having a neck, a resonance body including a top resonating panel and a bottom resonating panel, and a plurality of string means extending along the neck and the top panel, said bridge arrangement comprising:
(a) a first bridge means adapted to be in contact with said string means and secured to the top resonating panel; and (b) a second bridge means adapted to be in contact with said string means and secured to the bottom resonating panel;
said first bridge means, when mounted on a musical instrument, transferring vibration directly from said string means to said top resonating panel and said second bridge means, when mounted on a musical instrument, transferring vibration directly from said string means to said bottom resonating panel.
(a) a first bridge means adapted to be in contact with said string means and secured to the top resonating panel; and (b) a second bridge means adapted to be in contact with said string means and secured to the bottom resonating panel;
said first bridge means, when mounted on a musical instrument, transferring vibration directly from said string means to said top resonating panel and said second bridge means, when mounted on a musical instrument, transferring vibration directly from said string means to said bottom resonating panel.
2. A bridge arrangement as in claim 1 wherein the second bridge means is adapted to extend through a slot in the top resonating panel without contacting said top resonating panel and through the resonance body to the bottom resonating panel and to be fixedly secured to said bottom resonating panel.
3. A bridge arrangement as in claim 2 wherein the first bridge means comprises first string contacting means and at least one post adapted to connect said first string contacting means with the top resonating panel.
4. A bridge arrangement as in claim 2 wherein the second bridge means comprises second string contacting means and at least one post connected thereto, said post being adapted to extend through the slot in the top resonating panel without contacting the top resonating panel and through the resonance body to the bottom resonating panel and to be fixedly secured to said bottom resonating panel.
5. A bridge arrangement as in Claim 1 wherein the first bridge means comprises first string contacting means and at least one post adapted to connect said first string contacting means with the top resonating panel, and wherein said second bridge means comprises second string contacting means and at least one post connected thereto, said post being adapted to extend through a slot in the top resonating panel without contacting the top resonating panel and through the resonance body to the bottom resonating panel and to be fixedly secured to said bottom resonating panel.
6. A bridge arrangement as in claim 3, 4 or 5 wherein the length of each of said posts is adjustable.
7. A bridge arrangement as in Claim 5 wherein one of said first and second string contacting means is provided with a plurality of spaced apart openings or lower recesses adapted to receive the string means, said lower recesses facing, when the bridge means is mounted on a musical instrument, the top resonating panel, and wherein the other of said string contacting means is provided with a plurality of spaced apart openings or upper recesses adapted to receive the string means, said upper recesses being located in a portion of the string contacting means which, when the bridge means is mounted on a musical instrument, is remote from the top resonating panel, and wherein one of said string contacting means, when mounted on a musical instrument, holds the string means down in direction of the top resonating panel and the other of the string contacting means holds the strings away from the top resonating panel.
8. A stringed musical instrument comprising:
(a) a resonance body including a neck, frame means, a top resonating panel and a bottom resonating panel, each panel being mounted on said frame means;
(b) string means extending along said neck and said top resonating panel to provide a source of sound vibration;
and (c) a bridge arrangement including a first bridge means in contact with said string means and secured to the top resonating panel, and a second bridge means in contact with said string means and secured to said bottom resonating panel;
said first bridge means transferring vibration directly from said string means to said top resonating panel and said second bridge means transferring vibration directly from said string means to said bottom resonating panel.
(a) a resonance body including a neck, frame means, a top resonating panel and a bottom resonating panel, each panel being mounted on said frame means;
(b) string means extending along said neck and said top resonating panel to provide a source of sound vibration;
and (c) a bridge arrangement including a first bridge means in contact with said string means and secured to the top resonating panel, and a second bridge means in contact with said string means and secured to said bottom resonating panel;
said first bridge means transferring vibration directly from said string means to said top resonating panel and said second bridge means transferring vibration directly from said string means to said bottom resonating panel.
9. A stringed musical instrument as in claim 8 wherein said second bridge means extends through a slot in the top resonating panel without contacting said top resonating panel and through the resonance body to the bottom resonating panel, said second bridge means being fixedly secured to said bottom resonating panel.
10. A stringed musical instrument as in claim 8 wherein the first bridge means comprises first string contacting means and at least one post connecting said first string contacting means with the top resonating panel.
11. A stringed musical instrument as in claim 8 wherein the second bridge means comprises second string contacting means and at least one post connected thereto, said post extending through the slot in the top resonating panel without contacting the top resonating panel and through the resonance body to the bottom resonating panel and being fixedly secured to said bottom resonating panel.
12. A stringed musical instrument as in claim 10 or 11 wherein the length of each of said posts is adjustable.
13. A stringed musical instrument as in claim 8 wherein a plurality of spaced apart reinforcement ribs extend generally in the direction of the string means along the inside of the top resonating panel and along the bottom resonating panel.
14. A stringed musical instrument as in claim 13 wherein said first bridge means comprises first string con-tacting means and at least one post securing said first string contacting means to the top resonating panel and to at least one of said reinforcement ribs on the inside of the top resonating panel.
15. A stringed musical instrument as in claim 13 wherein the second bridge means comprises second string contacting means and at least one post connected thereto, said post extending through the slot in the top resonating panel without contacting the top resonating panel and through the resonance body to one of said reinforcement ribs on the inside of the bottom resonating panel, and said post being fixedly secured to said reinforcement rib.
16. A stringed musical instrument as in claim 13 wherein the first bridge means comprises first string contacting means and at least one post connecting said first string contacting means with the top resonating panel and with at least one of said reinforcement ribs on the inside of the top resonating panel, and wherein the second bridge means comprises second string contacting means and at least one post connected thereto, said post extending through the slot in the top resonating panel without contacting the top resonating panel and through the resonant body to one of said reinforcement ribs on the inside of the bottom resonating panel, and said post being fixedly secured to said reinforcement ribs.
17. A stringed musical instrument as in claim 16 wherein one of said first and second string contacting means is provided with a plurality of spaced apart openings or lower recesses for receiving the string means, said lower recesses facing the top resonating panel, and wherein the other of said string contacting means is provided with a plurality of spaced apart openings or upper recesses for receiving the string means, said upper recesses being located in a portion of the string contacting means which is remote from the top resonating panel, and wherein one of said string contacting means holds the string means down in direction of the top resonating panel and the other of the string contacting means holds the string means away from the top resonating panel.
18. A stringed musical instrument as in claim 16 wherein said first bridge means is located closer to the neck of the instrument than said second bridge means.
19. A stringed musical instrument as in claim 18 wherein said first string contacting means of said first bridge means is provided with a plurality of spaced apart recesses facing the top resonating panel,said recesses receiving the string means and holding said string means down in direction of the top resonating panel, and wherein said second string contact-ing means of said second bridge means is provided with a plurality of spaced apart openings receiving the string means and holding said string means away from the top resonating panel.
20. A stringed musical instrument as in claim 18 or 19 wherein, when one of the string means is plucked, said string means urges and moves said first bridge means, and thus the top resonating panel, outwardly and simultaneously urges and moves the second bridge means, and thus the bottom re-sonating panel, outwardly in the opposite direction, said outward movement of both resonating panels being followed by an inward movement of both resonating panels, so that the top resonating panel and the bottom resonating panel vibrate in opposite directions to each other.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000384350A CA1160081A (en) | 1981-08-21 | 1981-08-21 | Multiple bridge for stringed instruments |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000384350A CA1160081A (en) | 1981-08-21 | 1981-08-21 | Multiple bridge for stringed instruments |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1160081A true CA1160081A (en) | 1984-01-10 |
Family
ID=4120762
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000384350A Expired CA1160081A (en) | 1981-08-21 | 1981-08-21 | Multiple bridge for stringed instruments |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1160081A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4793233A (en) * | 1987-11-06 | 1988-12-27 | Olthoff Kenneth G | Mechanism for changing bridge support between alternate modes in stringed musical instruments |
| CN108682409A (en) * | 2018-05-14 | 2018-10-19 | 陈凡 | A kind of amplifier on violin |
-
1981
- 1981-08-21 CA CA000384350A patent/CA1160081A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4793233A (en) * | 1987-11-06 | 1988-12-27 | Olthoff Kenneth G | Mechanism for changing bridge support between alternate modes in stringed musical instruments |
| CN108682409A (en) * | 2018-05-14 | 2018-10-19 | 陈凡 | A kind of amplifier on violin |
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