July 1, 1952 R.J.M.C. /ANG/OYS 2,601,801 
TUNING FORK WITH SIMULTANEOUS MULTIPLE FREQUENCIES 

Filed Aug. 6, 1947 


Patented July 1, 1952 2,601,801 

U:NITED STATES PATENT 

2601,801: 
TUNïNG FORK WITHSIMULTANEOUS  
MULTIPLE FREQUENL'YIES: 
lémy;J.osepl-Mrie Cécile LtngloYs, Saint-Cloud, 
Seine-et, Oise,. France, asignor to.. Society 
"Etablissements Herrburger»' P;ariS,. France, .a 
corp orationo£ France 
Appliëti0n:August 6, 1947 SerîalNo: 766536: 
In France April 24, 1945 
Section-I, PublicLaw 690 Augusf 8,1946 
Pktent exlires April 24, 195- 
16 Claims. (CI. 84--457 ) 
The present-invention relates fO  tuning- 
frk  of; complex shRe whose- exeittiòn- by strik- 
iig o  by a- bow  or any other means generates 
simultSneously seVera  fndamental, frequencies. 
The object  of the invention will become ap- 
parent as the following detafled, dscription 
progresses, refërence being' hd fo the accom- 
pnyirrgdrawing, whezein= 
Fig. 1  illustratesa standard tuning«ï0rk; 
Figs. 2-8 illustrate various complex-shaped 10 
tunihg fbrks according to the invention, 
FÆg; 9" is a sectional .ewof a tuning fork ac- 
cording t0 the invention taken  on line- IXIX 
of  Fg: 3, wherein, however; thë tunlng fork 
pro.videdwith dampin means, and _ 1:5 
Ftgs« 10 and 11 are. partial vews«of the tuning 
f6rk shown in Fig. 3 provided with different 
typeS of.dampirgmeaus. 
Let'a sts:ndard-tuning-fork  be considered first 
on ,Fïg. 1  comprising; as well known a pah" of 
tines arranged in spaced parallel alignment. 
Let another tuning-fork 2 (Fig: 2) be also con- 
slderel wih no- rail as- the flrsL fork; in- which 
 tart/oi  the upper leg . is rep]aced by a fork 
 whieh is identieal witl fork- [. of Fig. 1. 
If thë 10wer fine of the fork  is strucl- in a 
vertical direction, le-complexshap.ed tuning 
f6rk (lower fine-,, rail memher . and double tine 
fork ') wfiI vibrate  as if ifs upper tine (rail 
member . and fork ' ) were identical fo: the 0  
said lower fine; the compound fork willvibrate 
as a. standard, tuning fork on ifs  normal pitch. 
On the contrary if.the upper tin-e of theupper 
f6k  is struck in  vertical direction the two 
ttmlng., fores 2aud  constituted by the tUree S 
tines wfll vibrate, generating simultaneously the 
fund'amental corresponding fo the .upper fork 
ad ' the fundamentoE1 corresponding fo the 
iower fork . For in faet the striking action 
on the uPper fine of' fork . wfllnot on!y vibrate 
the smalI' fork but" also  ifs rail portion - and 
conseuenZI the other" tuning fork . 
ur, all it is necessarY for making the-second 
f6rk X vbrate fo adj.ust ifs upper leg - which 
ha leen eut for flxing the af0resaJd fork.. 4 
According to the. same process It will be pos- 
siblC.to, build (ee. Figure 3) another complex- 
shaped _ fork. X, , 6 with three frequencies and 
so on; the final fork will ba fltted with a rail 
te mee.the service requirements. 50 
The shapes shown on Figs. 1, 2 ad  3 are non 
restrictive, it beingquite possiblefo bave shapes 
and désigns which differ widèly, from them, as 
f6r examplè those shown on ]igs: 4 and,' 5 The 
compound, or complex-shaped  tuntng f0rk au 55 

OFFICE. 

2 
erdingto'Figure . comprises  fixed f0rk  hav- 
ing fines ' and " and:a rail part 2  to.which 
is flxed  a fine '" forming a flrst- compound fork 
2i Ifl ifs t  the said fist compod fork 
is  owidèd with a' raff portion " to wch 
flxed in any appropriate manner -tine- " 
forng: a second cempod-fork compring. 
forks  nd   Finally, the :sid second  com- 
poud f0rk is provided with a-rail poion 
o which iS  flxed a tine " formg 
coped' fork; comprising thef0rks , ,   and 
 th . Iatr: eing proçided ith.  rail  cor- 
respendg fo thB  rail  o Fige :. AS ex 
plaed: ïor the compoun fork  in g 2 te 
comund fork accordg  fo îgre= 
sg action on he rs 6r  bates the 
rail part«y ad 'cosuelF th.st compound 
fork 2  and " it- rail portion ' which  makes: th 
second compod fork  to vibrate. e si 
sond  compound- for  vibratthe rail portion 
3'Wch in it trn makes: the.third compound 
fork  3 fo vibrate.  anF one oç these..f0rks 
brates  on- i  ow requencF, it cn be  seen 
thtthe compound fork of Figure 4 wen made 
t« ibrate generates ïo fundamental reuen- 
cies i e. those corrponding fo the 0r 
ad  respectivelF. f a compound fork 
eratg 5 fundmentals is: fo  be-designd 
cn be made by replacing  a part 
o the fork  and by ingt6  the remainin te 
Par anothersmller standard - 0rk. 
eral way a compód f0rk geneing 
mntals compres: 1 
The compound- foraccord fo 
similar o that. shown in e 4 and differs 
oy from the ler in that lI its tines are 
parallel fo each other ad bt at riht ' angles 
over the rail pórtion . 
The damental principle lies in the fact 
that each fork except th flst one is costitud 
bFa  complx f0r supportig on oe of 
a complex or standard" for. 
The various legs of the eemble can 
welded, brazed, or ruade oï one  singl  piéC. 
Th  constituent orks su as 
may be disposed in-diffèrent planes Ch maF 
b of advantage in certain cases (bverall 
sions relative desage of. ïrequencies, etcD. 
these.cases the plne of vibration of:eethe rations 
composite f0r r . hot in coo as: is the 
case in most of the orks sown :çhedrawing: 
Sch compound ïor is sho in. ô«which 
i - cóss-sectioat: vi ofig: 6. .son  in 
Fi: 6 th til pótlo  o. supporting: 
and $ together with the 2"qlë.e.como 


601801 
3 
plane whereas the tines ' and " whlch con- 
stitute the constituent fork  lies in a different 
plane. 
The vibrations of the compound forks accord- 
ing to the Figures . fo 5 do hOt only generate 
the fundamentals of the several forks but also 
the higher partials whlch are neglected as be- 
ing remote from the fundamentals by approxi- 
mately 3 octaves. If the ratio of these requen- 
cies of the upper partials 2, 3,  fo the frequency 
of the fundamental is tobe increased, the fines 
of the forks may be provided either ith notehes 
7, 3,  and I{} (Fig. 6), or with hollowed portions 
Il and 12 (Fig. 7) or with wèights such as I - 
The legs of a complex fork can perfectly be cal- 
ibrated so that the frequencies produced are for 
instance the 1st, .nd, 3rd, 4th, 5th and 6th har- 
monies of a given fundamental. 
The complex fork can thus replace strings in 
certain musical instruments such as the piano, 
harpsichord, harp, zither, etc. 
 It can replace with advantage the rods and 
forks used in certain musical instruments such as 
the dulcitene, typophone, celesta, xylophone, 
glasschord, etc. 
Besides those, forks can be used for all cases 
for which those various instruments instead of 
generating sounds through the channel of a 
sound-board would produce them through any 
amplifying system (for instance: a fork vibrating 
near a polarized coil transmitting induced volt- 
ages fo the terminals of a pick-up in a radio set, 
the final source of sounds being a loud speaker in- 
stead of the sound-board). 
 In this order of ideas the complex fork is quite 
advisable for constituting the vibrating elements 
of certain types of electric chimes vith a loud 
speaker. 
Figs. 9 te 11 show a new device for damping 
the forks described above. According to Fig. 9 
which is a section of Figure 3 along lines IX--IX 
each of the fines 6", 2", 4", ' of for example the 
compound fork of igure 3 is in contact with a 
small strip of felt 18, 18', 18", 1.8'" suspended 
from a common support 2{} by means of strip of 
cloth 9, 19', 9", 9'" which acts as a flexible 
articulation, the said common support being slid- 
able in order to permit the damper fo be put in 
service or to be put out of action. 
According te Fig. l0 which shows two tines cor- 
responding te any one of the partial forks of 
Figures . to 8 a lump of damping material 21 
«felt. wool, etc.) is inserted between the legs 2", 
", of the fork while according te Fig. 11 the 
damper consists of helical cofls 22, 22' ruade of 
wool or any other material wound and fixed upon 
legs 2", 4" of the fork ai appropriately chosen 
points. 
Naturally the invention of the complex fork is 
in no way limited to the embodiments shown and 
described and which were chosen only by way of 
example.. 
What I claim is: 
1. A vibrato:¢ complex fork having a support- 
ing reed and two oppositely 7ibrating tines 
secured fo said reed, in which one of said tines 
comprises a tuning fork, a first rail portion carry- 
ing said tuning fork, a vibratory tine fxed fo said 
first raff portion and a second rail portion fixed 
te said supporting reed. 
. A .vibrato:¢ complex fork having a support- 
ing reed and two opposed vibratable tines secured 
to said reed, in which at least one tuning fork is 
fixed to one.of said fines. 

4 
3. A vibratery complex fork having a support- 
ing reed and two opposed vibratable tines secured 
fo said reed, in which ai least one tuning fork is 
secured te one of said tines, said one tuning fork 
 being located in a plane different from that de- 
termined by the other tine and the supporting 
reed. 
4. A vibratery complex fork having a support- 
ing reed and two opposed vibratable fines secured 
l0 fo said reed, in which at least one tuning fork is 
secured fo one of said tines, said one tuning fork 
being located in the plane determined by the 
other tine and the supporting reed. 
5. A vibratory complex fork having a support- 
15 ing reed and two opposed ibratable tines secured 
te said reed, in which one of said tines carries 
at least one tuning fork having two opposed vi- 
bratable legs, and in which the other tine and 
at least one of said legs are provided with means 
20 for eliminating undesirable harmonics of the 
fundamentals produced by the vibrations. 
6. A vibratery complex fork according fo claire 
5, wherein said harmonic eliminating means in- 
cludes notches on said other tine and said one 
25 leg, said notches being located near the fixed 
ends thereof. 
7. A vibratery complex fork according to claire 
5, wherein said harmonic eliminating means in- 
cludes masses fixed fo the free ends of said other 
0 tine and of said one leg. 
8. A vibratory complex fork having a support- 
ing reed and a first fork including two opposed 
vibratable members secured fo said reed, in which 
one of said members carries at least a second 
5 tuning fork having two opposed /ibratable mem- 
bers and in which the other member of said irst 
fork and at least one of the members of said 
second fork are provided with damping means. 
9. A 7ibratery complex fork according to claire 
4{) 8, in which said damping means includes a strip 
of a damping material freely bearing on its as- 
sociated member. 
10.  vibratory complex fork according to 
claire 8, in which the damping means is formed by 
45 a lump of damping material inserted between the 
said other member of said first fork and said one 
member of said second fork. 
ll. A vibratory complex fork according te 
claire 8, in which the damping means is con- 
5{) stituted by a helical winding of a damping 
terial on its associated member. 
12. A vibratery complex fork having a sup- 
porting reed and two opposed vibratable tines 
secured to said reed in which one of said tines 
55 has a reduced length, and a succession of tunlng 
forks supported on the free end of said one tine, 
each fork in said succession except the last hav- 
ing a tine or reduced length carrying the next 
fork in said succession. 
60 13. A ibratory complex fork comprsing a suc- 
cession of progressively shorter tuning forks hav- 
ing each two opposed vibratable tines, all but the 
shortest of said forks having one tine shorter 
than the other and in which all but the longest 
65 of said tuning forks is carried by the shorter tine 
of the next longer tuning fork. 
14. A vibratery complex fork as defined in 
claire 12, in which each of said forks but the long- 
est extends over the free end of the longer tine 
7O of the next longer ïork. 
15. A vibratory complex ork as defined in 
claire 12, in which at least one tuning fork of said 
succession ii located in a plane different from 
that determined by the other tuning forks and 
75 the supporting reed. 


,601,801 

16. A vibratory complex fork as deflned in 
claire 12, in which all of the tuning forks of said 
succession and the supporting reed are located 
in a saine plane. 
RÉMY JOSEPH MARIE 5 
CECILE LANGLOS. 
REFERENCES CITED 
The following references are of record in the 10 
file of this patent: 

6 
UNITED STATES PATENTS 

Number 
116fl93 
137,643 
1,280,239 
2,433,160 
2,497,143 
2,522,302 

Name Date 
Arkins et al ......... July II, 1871 
Whitney ............ Apr. 8, 1873 
Kitching ............ Oct. I, 1918 
Rusler ............. Dec. 23, 1947 
Shonnard ......... Feb. 14, 1950 
Roth .............. Sept. 12, 1950