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Патент USA US3046932

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July 31, 1962
‘
L. J.-KUHAR
BOBBIN
CASE
CARRIER
FOR
‘
SEWING
MACHINES
" '
'
'
,
.
Filed May 19, 1958
INVENTOR.
Ludwig
I
Figs.
Kuhar
BY
7
é
ATTORNEY
United States Patent ()??ce
_
$346,922
‘ Patented July 31, 1962
2
I
carrier, there is provided a bobbin thread guiding slot 9.
3,046,922
BOBBIN CASE CARRIER FOR
SEWING MACHINES
The rear face of the flange 7 at the top thereof is milled
away at 10 and has a bore 11 to provide for needle clear- I
ance.
Ludwig J. Kuhar, Clark Township, N.J., assignor to The
Singer Manufacturing Company, Elizabeth, N.J., a cor
poration of New Jersey
Filed May 19, 1958, Ser. No.,736,160
3 Claims. (or. 112-431)
With reference to FIG. 3, there is illustrated a bobbin
case carrier construction in accordance with the prior art
methods and which includes a rotation restraining notch
in the body of the rotary hook for rotation of the hook
relatively to the bobbin case carrier. During operation of
the sewing machine, the bobbin case carrier is restrained
against rotation while the hook is rotated relatively there 20
the thread is drawn during the sewing operation, the inner
30.
In the prior construction, the rotation restraining
notch 8a was formed in three successive milling opera
The present invention relates to a bobbin case carrier of 10 tions. In the ?rst operation, a slot is milled in the face
of the flange 7 by a relatively wide cutter that passes
a sewing machine and more particularly to the formation
straight across the face of the ?ange 7 substantially ra—
of the rotation restraining notch in the bobbin case carrier
dially of the bobbin case carrier, thus producing the side
of a sewing machine.
walls 12 and the bottom 13 of the notch 8a. To avoid the
In a lock stitch sewing machine of the rotary hook
type, the bobbin is mounted in a bobbin case that is in 15 sharp corners of the inner end of the side walls 12 that
‘result from the first milling operation, over which corners
turn inserted in a bobbin case carrier which is mounted
to to seize and cast a loop of needle thread about the bob
bin case carrier. Since the needle thread loop must pass
completely around the bobbin case carrier, the rotation
restraining means must allow for passage of the thread
between the rotation restraining means and the bobbin
ends of the side walls 12 were ?ared or beveled outwardly
by means of relatively narrow cutters in the two subse
quent milling operations. These cutters were passed
through the slot at an angle to the center line of the slot,
thus producing the side walls 14 and 15 and the respec
tive bottoms 16 and 17.
Within the limitations of reasonably economical manu
facturing processes, the cutters in the milling operations
cannot be held to exactly the same depths with the result
that the bottoms 13, 16 and 17 do not coincide, or in
straining means comprises a ?nger mounted in the bed of
other words, do not de?ne a single continuous planar bot
the machine and having a tongue that is seated in a notch
tom for the notch 8a. In FIG. 3, there is illustrated the
in the face of the bobbin case carrier. This invention
relates speci?cally to the formation of this rotation re 30 condition that results when the left hand cutter is set at
a depth slightly less thm the depth of the initial straight
straining notch in the bobbin case carrier and has for an
cutter and the right hand cutter is set at a depth slightly
object to form this notch in such a manner as to facilitate
greater than the depth of the initial cutter. In this case,
manufacture.
the bottom 16 is above the bottom 13 with a resulting edge
Having in mind the above and other objects that will
be evident from an understanding of this disclosure, the 35 18 at the meeting line, and the bottom 17 is below the
bottom 13 and in effect cuts a groove in the bottom 13
invention comprises the devices, combinations and ar
case carrier. In the conventional manner, the rotation re
which produces edges 19.
p
_
rangements of parts as illustrated in, the presently pre
Since during the sewing operation, the limb of the
ferred embodiment of the invention which is hereinafter
needle thread must be swung laterally across the notch 8a
set forth in such detail as to enable those skilled in the
art readily to understand the function, operation, con 40 before the loop is withdrawn, the bottom of the notch 8a
must be smooth and continuous, or in other words, with
struction and advantages of it when read in conjunction
out edges such as at 18 and 19 upon which the thread
with the accompanying drawings in which:
could catch or snag and be thus held back. Thus, after
FIG. 1 is a plan view of a bobbin case carrier for a
milling in the prior construction, the bottom of the notch
rotary hook of a sewing machine, which bobbin case
45 8a had to be hand ?led to remove any edges, such as 1-8
carrier embodies the present invention,
l
and 19, resulting from the milling operations. Because
FIG. 2 is a fragmentary sectional view taken substan
the notch 8a is only less than one eighth of an inch wide
tially on the line 2-2 of FIG. 1,
and because the post 3 is located only three eighths of an
FIG. 3 is a fragmentary plan view similar to FIG. 1
inch from the inner edge of the side wall 1, this ?ling oper
and illustrating the prior art.
The present invention is herein disclosed as applied to 50 ation is very delicate and di?‘icult. At the same time, and
also because of the variations in the resulting edges in
a bobbin case carrier of a conventional type of rotary
the bottom of the notch 8a, this ?ling operation was per;
hook which is illustrated, for example, in the United
formed by hand. It is obvious that ?nishing of the bot
States patent of Kessler, No. 2,085,699, to which refer
tom of the notch 8a was an expensive operation.
ence may be had for an understanding of the function and
In accordance with the present invention there has been
55
. operation of the bobbbin case carrier.
provided a bobbin case carrier in which the rotation re
As illustrated in the drawings, the bobbin case carrier
straining notch 8 is formed in such a manner as to elim
is cup-shaped and comprises a cylindrical side Wall 1
inate the subsequent hand ?ling that is ‘required in the
which, to reduce the mass, has an open back that is
prior art construction. As illustrated in FIGS. 1 and 2,
spanned by a diameter bar 2. The bar 2 supports a cen
trally located stud '3 for mounting and latching the bobbin 60 the notch 8 in the present construction comprises an outer
case within the carrier.
For journaling the bobbin case carrier within the race
portion 20 in the form of a slot having parallel side walls
21 and a planar bottom 22. The outer portion 20, like
the slot formed in the ?rst milling operation in the prior
way of a rotary hook, there is provided a peripheral hear
art construction, is arranged substantially radially of the
ing rib 4 on the outer surface of the side wall 1. The
bearing rib 4 is discontinuous to provide a thread loop de 65 bobbin case carrier. To ?are the inner ends of the slot
outwardly there is an inner portion 23 comprising a de
taining shoulder 5 and a loop con?ning shoulder 6. On
pression milled in the face of the flange 7 to substantially
the needle thread loop cast off side, there is provided on
the same depth as the outer portion 20 and having an
the top of the side wall 1, a laterally extending loop con
inner edge which is de?ned by the coinciding inner edges
trolling ?ange 7 that extends beyond the top center of
of the side wall 1 and ?ange 7 and an outer edge which
the carrier and at the top thereof is provided with a notch
is arcuate with a diameter greater than the width of the
8 for receiving the tongue of a rotation restraining ?nger
outer portion 20 and arranged substantially centrally of
(not shown). On the cast on side of the bobbin case
3,046,922 \
V
3
4
V
the ‘center line of the outer portion 20.‘ The inner por
tion 23 is thus crescent-shaped and intersects the side
walls 21 of the outer, portion 20 to provide arcuate side
a cylindrical side wall and a laterally extending ?ange on
the top of said side Wall and having a rotation restraining
notch formed in the face of said ?ange, said notch com
prising an outer portion having a planar bottom and par~
‘edges 24 which constitute diverging side walls and thus
act to ?are outwardly the inner ends of the side walls 21
allel side walls extending generally radially relatively to
of the outer portion 20. The inner portion 23 includes a
said bobbin case carrier, and an inner portion having side
bottom 25 which, to avoid a sharp edge at its meeting line
Walls diverging inwardly and intersecting and constitut
with the bottom Wall 22 is arranged at a slight angle to the
ing bevels on the inner ends of, the side walls of said outer
plane of the bottom wall 22, the angle being illustrated at
portion and a planar bottom arranged at a slight angle to
A in FIG. 2 and being substantially three degrees. Thus,
the bottom walls 22 and 25 will alwayspintersect along a
the bottom of said outer portion.
7
2. A bobbin case carrier for a sewing machine having
line, such as 26, and will blend smoothly.
In the formation of the slot 8 in accordance with the
a cylindrical side wall and a laterally extending ?ange on
the top-of said side wall and having a rotation'restraining
present invention, the ?rst operation is the same as in the
notch formed in the face of said ?ange, said notch coni
priorvconstruction, i.e., the ?ange 7 is ?rst milled by a 15 prising an outer portion having a planar bottom and par
cutter that passes across the face thereof to provide a slot
allel side walls extendinggenerally radially relatively tgo ,.
and thus form the outer portion 20 of the notch 8. The
slot is then ?ared, as illustrated in FIG. 2, by a circular
end mill 27 having a diameter greater than the diameter
of the slot and advanced endwise onto said ?ange with
said bobbin case carrier, and a crescent-shaped inner por-v
tion having arcuate side walls intersecting and constitut~
ing bevels on the inner ends of the side walls of said outer'
portion and a planar bottom arranged ata slight angle to
. the axis thereof arranged at an angle of three degrees to
a line normal to the bottom wall 22 to form the inner por
the bottom of said outer portion.
'
"
3. A bobbin case carrier for a sewing machine having . a
tion 23 of the notch 8. Thus, the notch 8 has been com
a cylindrical side wall and a laterally extending ?ange on
the top of said side Wall and having a rotation restraining.
necessity of a subsequent hand ?ling operation. Any 25 notch formed in the face of said ?ange, said notch com
variations in the depth‘ of penetration of the end mill 27
prising an outer portion having a planar bottom disposed
from the designed optimum, while it may vary the posi
in a plane substantially normal to the am's of said bobbin
tion of the line 26 radially of the bobbin case carrier or ,
case carrier and parallel side walls extending generally _
may produce an edge along the line 26, it does not pro Y . radially relatively ‘to said bobbin case carrier, and an inner
duce any appreciable edges lengthwise of the notch 8 upon 30 portion having side walls diverging inwardly and intersect~
which the thread could snag as it moves laterally of the
ing and constituting bevels on the inner ends of the side
notch 8.
‘
walls of said outer portion and a planar bottom arranged
Numerous alterations of the structure herein disclosed’
at a slight angle to the bottom of said outer portion and
will suggest themselves to those skilled in the art. How
inclined radially inwardly of the bobbin case carrier to
ever, it is to be understood that the present disclosure 35 ward the opposite face of said ?ange from said notch. .
relates to a preferred embodiment of my invention which
References Cited in the ?le of this patent
isrfor purposes of illustration only and not to be con
, pletely formed in only two operations and without the
strued as a limitation of the invention.‘ All such modi?ca
tions which do not depart from the spirit of the inven
tion are intended to be included within the scope of the 40
appended claims.
Having thus described the nature of the invention, what
I claim herein is:
1. A bobbin case carrier for a sewing machine having
-
UNITED STATES PATENTS
1,179,371
Diehl et a1. ____'_ _____ __ Apr. 11, 1916
2,212,475 '
Karle ________ -Q. _____ __ Aug. 20, 1940
2,299,524
Chason ____________ .__‘__ Oct. 20, 1942
' 2,343,877
Zonis _______________ __ Mar. 14, 1944
2,633,776
Schenk ______________ __ Apr. 7, 19531
2,643,584
Wertepny et a1. _____ __‘__ June 30, 1953 ‘
i
n
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