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Full text of "US Patent 2601054: Looper mechanism for blind-stitch sewing machine"

June 17, 1952 F. PARRY 2,601,054 
LOOPER ECHANISM FOR BLIND STITCH SEWING MACHINE 
Filed Sept. , 1949  SHEETS--SHEET i 



June 17, 1952 F. PARRY 2,601,054 
LOOPER MECHANISM FOR BLIND STITCH SEWING MACHINE 
Filed Sept. 2, 1949 2 SHEETS--SHEET  



Patented June 17, 1952 

2,601,054 

UNITED STATES PATENT 

1 
This invention relates ,to sewing machines and 
more ,particulariy fo an improved looper mecha- 
nism for a single thread chain-stitch blind-stich 
sewing machine of the type .disclosed in the U. S. 
patent of C. A. Dearooïn, No. 814,642, dated 
March 6, 1906. 
In the machine 'disclosed in the bove men- 
tioned Deaborn patent, the looper is actuated 
by a crank having a crank-pin disposed so that 
its axis is arranged at an inclination fo the lon- 
gitudinal axis of the shaft carrying the crank. 
The manufacture of this inclined crank within 
the required tolerances involves a relatively .cosly 
procedure. Also, when an inc]ined crank is em- 
ployed, if is customary to use a .crank-pin em- 
bracing leeve to impart the necessary ,compound 
motion to the looper. Whfle this looper driving 
actuator is satisfactory in imlrarting the neces- 
sary motions, if requires considerable lubrication 
and more particulariy so during high speed opera- 
tion of the machine. 
If is the primary object of the present inven- 
tion to simplify ,the looper driving mechanism fo 
the extent that a ,looper-actuating .crank rnay be 
used having a crank-pin disposed parallel to the 
longitudinal axis of the shaft ,carrying the crank. 
Another object oÏ the inverion is fo provide 
the looper mechanism of a blind-stitch sewing 
.machine with an anchor link, whereby the rotary 
a'ctuator Ïor the looper may comprise a simple 
cranM 
The foregoing and other objects and advan- 
rages, together with means whereby ,the saine 
may be carried into effect, wfll best ,be understood 
from the ollowing description of a preferred em- 
,bodiment thereof illustrated in the accompany- 
ing drawings, in .wh,ch: 
Fig. 1 is a left side elevational view of a blind- 
stitch sewing machine mbodying my improved 
]ooper naechanism. 
Fig. 2 is a horizontal sectional view taken sub- 
stantially along the line 2--2, Fig. 1. 
Fig. 3 is a vertical sectiona/ view taken sub- 
stantial]y along the line 3--3, Fig. 1. 
Fig. 4 is a verti, cal sectional view taken sub- 
stantially along the line 4--4, Fig. 1. 
Referring fo the drawings, the machine illus- 
trated is one of the well known single thread 
blind-stitch sewing machines and comprises a 
frame including a oed  fo one end of which is 
.pivoted a work-supporting frame ! ! and from the 
other end of which rises a standard 2 terminat- 
ing in a fowardly extending arm ! 3. Journaled 
in. the standard 2 is a rotary main-shaft 4 
carrying ai one end a oelt-driven pulley ! § in the 

2,601,054 
LOOPER MECHANIS1V[ FOR BLIND-STITCH 
SEWING MACHINE 
Frank Parry, Bridgeport, Conn., assignor to The 
Singer iV[anufacturing Company, Elizabeth, 
N. J., a corporation of New Jersey 
Application September 22, 1949, Serial No. 117,160 
5 Claires. (CI. 112176) 

OFFI,CE 

2 
man_ner cleariy shovn in the previously men- 
tioned Deaborn Patent No. 814,642. Journaled 
in the forwardly extending arm ! 3 is a rock-shaft 
6 actuated af one end by means of a rock-arm 
5 I'/ and pitman 18 (Fig. 4) from a crank 19 car- 
ried by the rotary shaft 4. At its other end, 
the rock-short! 6 has clamped upon t a needle- 
carrier 20 in which i.s fasened a curved needle 
2 . As is customary in ,blind-stitch machines, 
10 the curved needle during the normal course of 
sewing enters and emerges from the material on 
the saine side thereof. The material fo oe 
stitched is adapted ,o be advanced .past the needle 
2! by a feed-dog 22 carried on the free .end of a 
15 feed-oar .23, which feed-bar is fulcrumed inter- 
mediate its ends on a pivot-pin 24 (Figs. 1 and 
3) carried in the upper .portion of an oscillatory 
link 2 supported by a short shaft 2 journaled 
in the arm |3 of the machine frame. Ai ifs end 
20 remote from the feed-dog 22, the feed-bar 23 is 
enlarged to embrace an actuating eccentric 
carried by the main-shaft |4. lotation of the 
main-shaft |4will impart substantilly a four- 
motion travel fo the feed-dog 22, which feed-dog 
25 engages the .top of the work and, during its work- 
advancing stroke, is opposed by the work-sup- 
porting frame | |. 
Cooperating with the thread-carrying curved 
needle - | in the formation of single thread chain- 
30 stitches is a looper 28 of ,conventional construc- 
tion. The looper 28 is adjustbly mounted in an 
offset looper-clamp 2S which is secured on one 
end of a looper-carrying shaft 30 journaled for 
oscillation in the spaced bearing lugs '| and 
3 of a looper-frame 33. Af its rear end, the looper- 
 frame 33 is apertured fo receive a needle-bearing 
34 (Fig. 2) mounted on a crank-pin 
axis disposed parallel fo the longitudinal axis of 
the main-shaft |4. The crank-pin 3 is pref- 
40 erbly formed on a mounting ,plate 8 havin a 
centrally disposed locting projection 3 and an 
arcuate slot 38 (Fig. 1) through whi,ch extends a 
clamping s,crew 3S threaded into a disk or coun- 
terweight 40 o,f the needle-actuating crank |. 
4 The purpose of the arouate slot 33 and the clamp- 
ing screw 3S is fo ,permit adjustment of the crank- 
pin 35 about the locating projection 3 to change 
the timing of the looper .-8 with respect to the 
needle 2 |. 
0 It wi]l be understood that in blind-stitch sew- 
ing machines of the type illustrated in the draw- 
ings, the looper after advancing fo enter and 
seize the thread-loop presented by the needle 
carries the seized thread-loop upwardly and 
 backwardly over the material and then down- 



wardly to position the seized needle-thread-loop 
for entrance by the needle just before said needle 
penetrates the work on ifs next stroke. Con- 
trolled up-and-down motions of the looper 
are obtained by pivotally supporting the looper- 
frame 33 at the lower end of a depending link 
which is fulcrumed at its upper end on a shoul- 
dered pivot-stud 42 having an offset shank 
located eccentrically in a bushing 44 secured by 
set screws 45 for turning adjustment in the arm 
3. The lower end of the depending link 4 is 
bifurcated (Fig. 3) to provide two limbs 4 a and 
4 b which are preferably spaced to just engage 
the sides of the looper-frame 33, whereby the 
looper-frame is steadied and any cramping ac- 
tion between the looper-frame and the crank-pin 
35 is minimized. A cap-screw 48 threaded into 
the end of the pivot-stud 42 retains the link 
on the pivot-stud. 
In addition to the up-and-down and the back- 
and-forth motions of the looper 2, the saine is 
oscillated about the longitudinal axis of the 
looper-carrying shaft 3G to properly position and 
spread the thread-loop for entrance by the 
needle. The oscillations of the looper are 
tained by means of an anchor-link cormection 
between the looper-carrying shaft SG and the 
stationary arm . As shown in Figs. 1 and 
the looper-carrying shaft G has clamped on it a 
short rock-arm 4 terminating in a ball 48 em- 
braced by the socketed lower end of an extensible 
anchor-link 49 connected at its upper end by. a 
stud 50 to the machine-afin . As the looper- 
ïrame 3S travels in response to the rotation of 
the crank-pin 5 and the swinging movement of 
the link 4 , the anchor-link 4 causes the looper- 
carry shaft SG to turn in its supporting bearing 
lugs  and . 
From the above description, it will be under- 
stood that the necessary looper motions are de- 
rived from a simple rotary crank which is 
mounted directly on the main-shaft of the 
machine. Not oniy is the crank 3 simple to 
manufacture, but by having the crank 5 fas- 
tened for limited circular adjustment about the 
axis oï the shaft 4, as by the slot SS and the 
screw $9, convenient adjustment in the looper 
timing may be ruade. Facilitating the proper 
timing and positioning of the looper 2S relative 
to the curved needle 2, is the eccentrically 
mounted pivot-stud 42 for the depending link 4  ; 
adjustment of the sleeve 44 in which the pivot- 
stud  is mounted serving to raise or lower the 
looper . Additional adjustment of the looper 
28 can be obtained by turning the offset looper- 
clamp  on the looper-carrying shaft. 9, by 
turning the looper 8 in the looper-clamp , 
and/or by ad]usting the length of the anchor- 
link . It will be understood that the provision 
of the anchor-link 9 hot only simplifies the type 
of rotary actuator $5 employed for actuating the 
looper S, but it also permits the oscillatory 
"motions which are irnparted to the looper 2 to 
be reduced to the minimum required ïor proper 
stitch-formation. In other words, by properly 
iocating the anchor-link 4 with respect to the 
rotary crank S and the link 4 the required min- 
imum oscillation of the looper can be obtained. 
ïn prior machines in which the looper is actu- 
ated by an inclined crank the inclination of the 
crank must be such as to satisïy a plurality of 
critical positions oï the looper relative to the 
needle and, in satisïying certain of these, the 
inclination of the crank is determined, leaving 
the oscillations of the looper about the longitudi- 

2»601,054 " 
4 
nal axii of the looper-shaft excessive. The 
design of my improved mechanism ii iuch that 
the exact amount of oscillation of the looper can 
be obtained without in any way affecting the 
5 design or.dimensions of the rotary actuator 3. 
Having thus described the nature of my inven- 
tion, what I claim herein is: 
1. A looper mechanism for a blind-stitch sew- 
ing machine having a machine-frame and a 
10 thread-carrying needle, comprising a looper com- 
plemental to said needle in the formation of 
chain-stitches, a looper-carrying shaft, a mova- 
ble looper-frame in which said shaft is journaled, 
means supporting said looper-frame, a rotary ac- 
15 tuator operatively connected to said looper- 
frame, and an anchor-link operatively connected 
to said looper-carrying shaft and to said frame 
and arranged to oscfllate said shaft relative to 
said looper-frame when said looper-frame is ac- 
20 tuated. 
2. A looper mechanism for a blind-stitch sew- 
ing machine having a main actuating shaft and 
a thread-carrying needle; comprising a looper 
complemental to said needle in the formation of 
25 chain-stitches, a movable looper-frame, a ruera- 
ber supporting one end portion of said looper- 
frame, a crank-pin carried by said main actuat- 
ing shaft and operatively cormected to said 
looper-ïrame, said crank-pin having its axis dis- 
30 posed parallel to the longitudinal axis of said 
main actuating shaft, a looper-carrying shaft 
]ournaled in sid looper-frame, and an anchor- 
link operatively cormected to said looper-carry- 
ing shaït and arranged to oscillate said looper- 
35 carrying shaft relative to said looper-frame when 
the latter is actuated. 
3. A looper mechanism for a blind-stitch sew- 
ing machine having a frame in which is jour- 
naled a main rotary shaft, and a needle opera- 
0 tively connected to said shaft; comprising a 
looper complemental to said needle in the forma- 
tion of stitches, a movable looper-frame, a link 
pivotally supported on said frame and bifurcated 
at one end fo straddle and pivotally carry one end 
of said looper-frame, a rotary crank-pin carried 
45 by said main shaft and operatively connected to 
said looper-frame, a looper-carrying shaft jour- 
naled in said looper-frame, a rock-afin clamped 
on said looper-carrying shaft, and an anchor- 
link connected at one end to said rock-arm and 
50 at ifs other end connected to said frame. 
4. A looper mechanism for a blind-stitch sew- 
ing machine having a frame in which is journaled 
a main rotary shaït, and a needle operated by 
said rotary shaft; comprising a looper comple- 
55 mental to said needle in the formation of stitches, 
a movable looper-frame, a member pivotally sup- 
porting one end portion of said looper-frame, a 
crank-pin carried by said rotary shaft and oper- 
atively connected fo said looper-frame, said 
60 crank-pin having its axis disposed parallel to the 
longitudinal axis of said main rotary shaft, a 
looper-carrying shaft journaled in said lo0per- 
frame, a rock-arm clamped on said looper-carry- 
65 ing shaft, and an anchor-link connected at one 
end to said rock-afin and at its other end adapted 
to be connected to said frame, said anchor link 
being constructed so that its length can be regu- 
lated to change the timing of the looper with re- 
70 spect to said needle. 
5. A looper mechanism for a blind-stitch sew- 
ing machine having a machine-frame providid 
with a main actuating shaft and a thread-carry- 
ing needle; comprising a plural-motion loopir 
ii complemental fo said needle in the formation of 



chain-stitches, a looper-frame movable in a sin- 
gle plane thereby fo impart certain of the mo- 
tions fo said looper, means for moving said looper- 
frame inc]uding a member supporting one end 
portion of said ]ooper-frame and a rotary actua- 
tor operative]y connected fo the other end of said 
looper-frame, a looper-carrying shaft journaled 
in said looper-frame and movable to impart other 
of the motions to said looper, and means for 
moving said looper-shaft relative to said ]ooper- 
frame including a rock-ara carried by said 
looper-carrying shaft, and an anchor-link con- 

l0 

6 
nected af one end fo said rock-arm and at ifs 
other end fo said machine-ïrame. 
FIANK PAIIY. 
IEFEIENCES CITED 
The following references are of record in the 
file of this patent: 
UNITED STATES PATENTS 
Number Name Date 
814,642 Dearborn ........... Mar. 6, 1906