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Патент USA US3051118

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Aug. 28, 1962
Filed Aug. 24, 1961
W $2,954
3,051,108 p
Patented Aug. 28, 1962
1 .
rotation of the bobbin case with respect to the loop
The'bobbin case 22 is formedwith a stud>25
disposed substantially co-axially of the loop-taker drive
Stanley J. Ketterer, Morris Piains, NJ, assignor to The
Singer Manufacturing Company, Elizabeth, N3., a cor
poration of New Jersey
Filed Aug’. 24, 1961, Ser. No. 133,604
3 Claims.
(Cl. 112-181)
shaft 15 and internally threaded to accommodate a
headed screw 26. Journaled freely on the stud 25 is a
bobbin member 27 which is constrained for limited slid
ing movement axially of the stud‘ by the headed screw
The loop-taker is preferably operated‘ in timed rela
This invention relates to lock stitch sewing machines 10 tion with the needle two revolutions for each needle
of the type in which locking or bobbinijtbread is re
reciprocation and in a timed relationship such that the
plenished automatically during a continuation of the
loop-taker beak 19 will pass adjacent to the needle dur
same interrelated motion of the needle and the loop- >
ing each work penetration thereof for seizure of needle
taker as is required for the formation of lock stitches,
thread loop whenever a loop of thread is presented by
‘and more particularly to a novel means for rendering 15 the needle. Such interrelated motion of the needle
inelfective the locking or bobbin thread tensioning means
and loop-taker is termed stitch forming motion and it
during the thread replenishing operation.
will be understood that the same stitch forming motion
It is an object of this invention to provide a means
of the needle and loop-taker occurs during bobbin
for releasing the under or bobbin thread tensioning
thread replenishment even though no stitches will be
means during introduction and replenishment of a thread
formed during the replenishing period.
on a bobbin in place in a loop-taker so as to provide
Referring to FIG. 4, a gap 39 is formed in the bobbin
for the smooth'?ow of thread thereto with a minimum
case bearing rib 21 providing an ingoing pocket 31 on
of stress thus reducing the possibility of thread break
that side of the gap toward which the loop-taker turns,
against which pocket loops of thread seized by the loop
t is also an object of this invention to provide a 25 taker beak 19 are directed in the normal ‘handling of
novel under or bobbin thread tension releasing means
which is compact, simple, and economical in construc-_
tion and which does not interfere with the operation
of the thread replenishing mechanism.
In the accompanying drawing of a preferred em
FIG. 1 represents a vertical cross-sectional view of a
sewing mechine loop-taker having this invention applied
thread loops by the loop-taker. During the sewing op
eration when a free space exists behind the bobbin,
and bobbin case as illustrated in FIG. 2, the loops
of thread which are carried into the ingoing pocket by
the hook beak are free to slide about the bobbin case,
one limb across the exposed face and one limb‘ through
the free space behind the bobbin case. During sewing,
the portion of the loop which is initially trapped in the
thereto and including a fragment of the work support
ingoing pocket thus gradually slides across the gap 30 in
and the needle and illustrating the relative position of 35 the bobbin case hearing rib and is positioned at the op
parts during introduction and replenishment of bobbin
FIG. 2 represents a vertical cross-sectional view of a
sewing machine loop-taker similar to FIG. '1 but illus
trating the relative position of parts during the subse
quent sewing operation,
FIG. 3 represents a-front elevational view of the loop
taker of FIGS. 1 and 2,
FIG. 4 represents a top plan View of the. bobbin case,
FIG. 5 represents a perspective View of the thread
posite side of the gap 30, which is termed the outgoing
pocket 32, as the thread is drawn from the loop-taker
and set into the work.
Referring to FIGS. 1 and 2, 40 indicates a bobbin.
winding member carried within the cup-shaped loop
taker body and interlocked for rotation with the loop
The bobbin winding member is fast on a rod
41 shiftable axially Within the hollow loop-taker ‘drive
shaft 15.
By means of a control ‘mechanism (not
45 shown) which may be in the form of a cam means as '
described in the above referenced patent application No.
tensioning spring of this invention.
15,955, the rod 41 maybe shifted to position the bobbin
This invention is an improvement of the construction
winding member into engagement with the bobbin mem
disclosed in the copending United States patent applica
ber 27 as illustrated in FIG. 1, in which position thread
tion of Stanley J. Ketterer and William J. Edwards, 50 wili be replenished on the bobbin. After the bobbin
Serial No. 15,955, ?led March 18, 1960. This copend
thread supply has been replenished, the rod 41 shifted
ing application may be referred to for the details of
to the right as viewed in FIG. 2 to shift the bobbin
construction of the loop-taker, particularly with regard
winding member away from the bobbin member thus
to the means for introducing and replenishing a supply
readying the loop-taker for the formation of stitches.’
of under or looking thread to the bobbin and thereafter 55
A leaf spring 42 carried on the loop-taker body por
forming a lock stitch using the replenished bobbin
extends in spaced relation behind the loop-taker
thread supply.
beak 19 and is engaged by a thread gripping arm 43
In the accompanying drawing, the sewing machine
on the bobbin winding member 49 when the bobbin
work support, as indicated at 11, is ?tted with a throat
thread is to be replenished so as to grip on the hook
plate 12 having an aperture 13 through which passes 60 a loop of needle thread seized thereby. The bobbin
an endwise reciprocable thread carrying needle 14. I our
winding member is formed with a rim 44 which, as illus
naled beneath the work support is a hollow loop-taker
trated in FIG. 1, envelops the bobbin member when
drive shaft 15 to which is ?xed a loop-taker indicated
the bobbin winding member is shifted into engagement
generally as 16. The loop-taker is formed with a cup
therewith. The movement to the. left of the bobbin
shaped body portion 17 formed with a gap 18 and at 65 winding member during bobbin thread replenishment
one side of the ‘gap with a needle loop seizing beak
shifts the bobbin member axially along the stud 25 as
19. ‘The cup-shaped body portion of the loop-taker
illustrated in FIG. 1, and a pin 45 on the bobbin Wind
is formed internally with an annular raceway 20 in
ing member engages a notch 46 in the bobbin member
which is journaled by means of a bearing rib 21, a
to provide for a positive drive of the bobbin member.
bobbin case 22. The bobbin case is formed with a notch
When the bobbin winding member is shifted into the
23 which accommodates a rotation restraining ?nger 24
position illustrated in FIG. 1 for replenishment of the
?xed relatively to the Work support, thus to prevent
bobbin thread supply, the free space behind the bobbin
thread tensioning spring anchored on said bobbin case
and having ‘a free extremity biased yieldingly against
~ case is closed, andthe thread, loop carried by'the loop,
taker beak into the ingoing pocket 31 is constrained
therein. An L-shaped thread guided slot is formed in
the bobbin case having a limb 50 extending from~ the
ingoing pocket 31' and a limb 51 extending across the
said bobbin case, means e?ective during said interrelated
motion of said needle and loop-taker as is required
for the formation ‘of lock “stitches for introducing a
thread between the free extremity of said thread tension
face of the bobbin case through which slot the thread
is directed as it is ‘introduced to the bobbin. Secured
spr-ing and said bobbin ease and to said bobbin, bobbin
winding means including ‘a bobbin rotating member shift
to the bobbin caseras by screwslsz is a thread tension
able in adireotion axially of said bobbin into eliective
ing spring 53 having a free extremity 54 disposed in
the limb 51 of the thread accommodating slot. The free 10 driving engagement therewith and effective during con
tinued interrelated motion of said needle and loop-taker
1' extremity of 'the ‘thread tensioning springv is biased
against one wall ‘of the limb 51 of the thread accom~
modating slot as illustrated’ in FIG. 2 so to apply a
as is required for the formation‘of lock stitches for wind
- ing on said bobbin said thread introduced thereto, and
means operated by said bobbin winding ‘means for
frictional resistance to the passage of‘thread to or
from the bobbin to the work. A ?nger 55 is formedon 15 Shifting the free extremity of. Said' threadtensiening
spring away, from said bobbin case during operation of
the free extremity 54 of the thread tensioning spring,
said means for introducing thread to said bobbin and
which ?nger extends, as illustrated in FIGS. 1, 2 and
,3, into the axial. projection of the bobbin member 27
such that upon axial sliding movement vof the bobbin
during operation of said bobbin’ winding means.
along the stud 25 when engaged by the bobbin winding
member 40, the bobbin member will engage the ?nger
2, A mechanism as set forth in claim 1 in which said
means for shifting the, free extremity of said thread ten
sioningspring away from. said bobbin case comprises
55 and shift the thread tensioning spring away from that
' edge of the thread guiding slot toward which it is biased.
a With thisI construction, therefore, during introduction
bobbin atthe opposite side‘ ofsaid bobbin from said.
a ?nger carried by said thread tensioning spring and
disposed in the path of axial sliding movement of said
and replenishment of thread to the bobbin, the bobbin
thread 'tensioning means will be’ rendered ineffective and
the smooth ?ow ‘of thread thereto will be unimpeded,
thus minimizing the possibility of thread breakage. The
tension will be'automatioally reapplied when the parts
. "are shifted into position for sewing.
f 'In FIG. 1, in which the parts are illustrated in a posi
tion for bobbin thread replenishment, the loop-taker
V 3. A loop-taker for a lock stitch sewing machine'com:
prising a rotatable’ cup-shaped loop-talker body formed
with a gap, a loop seizing beak carried ‘by said loop
taker body and projecting into said gap in the, direc
tion of rotation of said loop-taker body, said loop
taker body being formed with an annular internal groove
' de?ning a raceway, a non-rotating bobbin case formed
‘with a cavity, a bearing rib formed on said bobbin case
beak 19 is illustrated in a position in which it has seized
a loop of needle thread T“. The bobbin thread tension
and journaled in the raceway in said loop-taker body,
said bear-ing rib being formed with a gap, one, edgeof
said gap in said bobbin case bearing rib toward which
ing spring5'3, as illustrated in this ?gure, is held in an
ineffective position for introduction and replenishment
vof the bobbin thread free of any e?ect of the tensioning
said loop-taker body, rotates de?ning an ingoing threadv
pocket, at bobbin journaled in said bobbin case for turn:
ing and limited axial sliding movements therein, a thread’
In FIG. 2, the loop seizing beak 19 of the loop-taker
is similarly illustrated in a position seizing a loop of 40 guiding slot formed in said bobbin case open to said
bobbin case cavity and leading fromv said ingoing
needle thread 'I‘11 ‘and the thread which had previously '
pocket,’ a thread tensioning spring means carried by said
been replenished ‘on the bobbin is indicated ‘at Tb, under
bobbin case and yieldingly bearing against one wall of
the in?uence of the bobbin thread tensioning spring 53.
said thread guiding slot, and a ?nger formed on said
j Having thus set- forth ‘the nature of this invention,
what I claim herein is:
- ‘
1. A look stitch sewing machine, having a frame'in
. eluding a work support, an endwlise reciprocatory thread
carrying needle carried by said frame at one side of-said
work support, a loop-taker journaled for turningmove
, ment- in the frame at the opposite side of said work sup
port, means for imparting interrelated motion to said'
thread tensioning spring means and extending ‘into the
path of axial sliding movement of said bobbin for shift
ing said thread tensioning spring means away from‘ said
one wall of said thread guiding slot upon axial shifting
References Cited in the ?le‘ of this patent
needle and said loop-taker as is required for the forma
tion of lock stitches, a bobbin case journaled in said
Stephenson. ___'____.__._._>__. Feb. 4,‘ 1931
taker, a bobbin journaled in said bobbin ease for turn
France ________ _'___'..____' Oct. 5, 1959
ing and
France -__,_______;____,__v,_ Feb, 8, 1960
loop-.taken'meaus carried on said frame for constraining
' said bobbin case from turning movement with said loop- '55
axially sliding >movement therein, a
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