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Патент USA US2121884

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» v June 28, 1938.
Original Filed July 13, 1935
2 Sheets-Sheet 1
` 'mmm
_zam-f 7% 6%,
`lune 28, 1938.
l 2,121,884
original Filed July 15, 1935
2 sheets-sheet 2
Patented June 28, 1938
Emil Prazak, Elizabeth, N. J.
`Substitute for application Serial No. 680,166,
July 13, 1933. This application December 3,
1935, Serial No. 52,653
2 Claims. (Cl. 112-158)
This invention relates to improvements in sew
ing machines adapted to effect in operation pre
determined pattern stitching; this application be
ing a substitute for applicant’s prior application
5 Serial No. 680,166, filed July 13th, 1933.
The invention has for its principal-object to
provide a novel construction of sewing machine
having improved means for varying the stitch
formation so as to produce pattern effects upon
10 the material sewn, such, for example, as "dotted
swiss” effects and various other design eifects.
To this end the machine comprises a novel ad
justable means for automatically varying the feed
of material sewn upon, in combination with means
in the above described views, to indicate corre
sponding parts.
Referring to the drawings, reference character
I0 indicates thevbase of a sewing machine having
an upstanding pedestal I I from which projects 5
the arm I2, which is spaced above and which over
-hangs base I0. At the free end of arm I2 is the
vertically disposed head I3.
Journaled in arm I2, so as to extend longitudi
n_ally therein, isa drive shaft I4. Pivotally con- l0
nected at I5 with the upper end of head I3 is a
dependent oscillatable needle-bar guide frame
I6, which slidably supports a vertically recipro
cable needle-bar I'I equipped at its` lower end
for automatically varying the needle bar opera
tion of the machine to produce groups of straightV
run or longitudinal stitches formed under normal
or maximum feed conditions, alternated with
groups of substantially laterally extending
with the usual sewing needle I8. Needle-bar I'I l5
is reciprocated by the usual crank transmission I9
which is actuated by drive shaft t4. Fixed on
drive shaft I4 is a sprocket wheel 20 which drives,
through belt 2|, a sprocket wheel 22- of shaft 23
20_ stitches, formed under reduced feed conditions; journaled to extend beneath base IIJ and which 20
the arrangement of feed variation control being actuates the rotary shuttle (not shown) of the
such that the amplitude of reduced feed is sub
machine sewing mechanism.
Supported by head I3 is the usual vertically
ject to quick and easy adjustment within the
range of the amplitude of the normal feed for yieldable presser foot 24 which cooperates with the
25 straight run stitches, thus permitting a consid
feed-dog means 25 by whichy the material sewn 25
erable range of variation of lateral stitch spacing, » is controlled and advanced relative to the sewing
with consequent variation or modification of pro
mechanism. The operative movement of feed
duced pattern or design effects.
dog means 25 comprises a compound of rising
Other objects of this invention, not at this timeV and fallingor vertically reciprocal movement and
30 more particularly enumerated, will be apparent forward and back or horizontally reciprocal move- 30
v in the following detailed description of the in
An illustrative embodiment of the invention is
ment. The
which brings the feed-dog means into and out ofv
operative contact with material sewn,‘is effected
through oscillation of a rock-shaft 26, the os
shown in the accompanying drawings, in which:
Fig. 1 discloses a vertical longitudinal sectional ‘ cillations of which are produced by an eccentric 35
view of the machine equipped with improvements 21 operatively connected thereto by connecting
vaccording to this invention, certain parts being rod 28. Said eccentric 21 is nonadjustable as to
shown inside elevation; Fig. 2 is a horizontal stroke or throw. The horizontally reciprocal
sectional view, taken partially in the plane of the movement, which causes the feed-dog to advance
drive shaft and partially in the plane of the feeder the material sewn‘in the formation of each stitch, 40
means of the machine; Fig. 3 is a fragmentary isI effected through oscillation of a rock-shaft 29,
~ vertical longitudinal section, taken on line 3--3 in
the oscillations of which are produced by an ec
Fig. 2; Fig. 4 is a fragmentary transverse vertical
centric 30, operatively connected thereto by con
ated connecting rod being omitted, »this viewl
necting rod 3l. Said eccentric 30 is adjustable
45 section, taken 'on line 4-4 in Fig. 1, and drawn on - to vary its effective stroke or throw underk certain 45
¿an enlarged scale, the associated eccentric actu
showing the feed control means operative for re
V.duced feed operation; Fig. 5 is a view similar to
50 that of Fig. 4, but showing the feed control means
operative for normal or maximum feed opera
tion; Figs. 6, 7 and 8 respectively show various
illustrativev‘examples of pattern effects attained
by the> improved sewing machine of this invention.
Similar characters of reference are employed
The means whereby eccentric 30 is rendered ad
justable to vary its effective stroke or throw, and
thus alter` the amplitude of material feed move--'
ment ‘of feed-dogmeans 25"comprises a frame l32 50
of which eccentric 30y is a part.
This frame> A32 ~
is provided at its underside with an arm v33 piv
otally secured, byv pivot means 3_4, to the face „
of sprocket wheel 20, so' that the framel and ec
centric 30 may be moved relative to axis of drive 55
' '
shaft I4 by which the frame and eccentric is ro
or race 55.
To the downwardly extending arm
59 of said lever member is adjustably connected
tated through its connection with sprocket wheel
one end of a connecting rod 60, the opposite or
20. At its upper side, frame 32 is provided with a
lug 35 having a slot- 36 concentric to the axis of
outer end of which is pivotally connected with
the needle-bar guide frame I6. The cam' groove
pivot means 34. Fixed on the adjacent face
of said sprocket 20 is a stud 36’ which projects
into said slot 36. Into one side of said lug 35 is
threaded an adjustable stop-screw 31 which en
ters an end of said slot 36. Threaded downward
ly through the end of saidlug 35 is a- set-screw
or race 55 is shaped throughout a »portion of its
length to provide a race-portion concentric to
the axis of said cam wheel, whereby, when such
portion engages roller stud 58, the lever member
51-59 is held stationary, to in turn hold the 10
needle-bar guide frame I6 stationary in perpen
dicular positionwhen straight run or longitudinal
stitches are being formed; the remaining portion
38, which can be tightened down into binding
relation to said stop-screw 31, to thereby secure
the latter against displacement from any selected
operative position to which it has been adjusted.15 The frame 32 and eccentric 38 carried thereby
of said cam groove or race 55 is of waving forma
tion, whereby, when such portion engages roller
stud >58, .lever member 51--59y is oscillated to in
turn swing laterally back and forth the needle
bar guide frame I6 to produce the substantially
are provided with an opening 39 of greater diam
eter than that of the drive-shaft I4, and through
which the latter extends. At one side of frame
lateral stitches. , Cam wheel 5| is further pro
32 is provided a laterally extending _arm 40 hav
20 ing a tubular bore 4| extending longitudinally, vided in its face with a second cam groove or'race 20
6|. Pivotally mounted on the pedestal || is a
therethrough. Arranged in the bore 4| is a corn
pression spring 42, the outer end of which is rocking arm 62 provided with av roller stud 63
backed by a seating screw 43 which -is threaded to engage in said cam groove or race 6|. Said
rocking arm 62 is connected by link 64 with aV
second rocking arm 65 which is fulcrumed by a
into the outerend of bore. 4|. The. innerrend of
spring 42 yieldably thrusts against the> side of
driveshaft. I4. At the oposite side of frame 32
»is an oppositely‘and laterally‘extending arm `44
having an internally screw-threaded _bore 45.
Threaded intobore 45 is 4,the threaded base 46 of
30 a thrust pin 41, the latter .extending through the
to said pedestal | |. Fixed on said rook-shaft 66
is a push-lever 68, the free oscillatable end of
which is opposed to the outer end of said plunger
Said plunger carries at its outer'end a dia .3.0
frame opening 39 and through the side of drive
metrically enlarged end-piece 69, which is out
shaft _|4, 4with .its free end ¿disposed within a
wardly thrust by means of a compression spring
hollow tubularinterior orI bore 48 with which said
drive-,shaft |4- is provided. _Slidable in the in
terior or bore 480i said drive-shaft |4 is a plunger
rock-shaft 66 journaled in a bracket 61 attached . .
i 10 to dispose said plunger 49 in retracted position.
Cam groove or race 6I is shaped to provide an
outer concentric portion and an inner concentric .35
49 having at its inner end a‘conical cam-portion
50. The outer end of said plunger 49 lprojects
exteriorly from the'end of- said drive-shaft I4.
portion, the latter being operatively engaged by
Whenvsaid `plunger is slid or pushed inwardly, its
conical cam-portion 50 is moved against the
thrust pin 41, thereby pushing the same outward
ly, and thus swinging frame 32 and its eccentric 36
about the pivotal connection 34, against the com
pression of spring 42, to carry the eccentric 30
thrust to in turn hold eccentric 30 in maximum .
throw position so as to actuate the feed means
to maximum offset relation to the axis of drive
shaft I4, i. e. to its normal maximum eccentric
stroke or throw, under which conditions the
straight run or longitudinal stitches are produced.
When said plunger 49l is retracted to free thrust
the plunger control means so as to permit plunger
49 to be retracted, to in turn hold eccentric 30
pin 41 from the engagement thereof, spring 42
exerts its thrust upon frame 32 to swing the same
in the opposite direction until stopped by the en
From the above description it will be obvious
that, by the operation of the machine, a. pattern
or design stitching may be'sewn` onto material,
gagement of stop-screw 31 with the ñxred stud
36', thereby disposing the eccentric 30 in mini
mum offset relation to axis of drive-shaft I4, i. e.
for «predetermined minimum eccentric `stroke or
roller stud 63 to swing inwardly the plunger con
trol means so as to hold plunger 49 inwardly
at major amplitude during the production of
straight run or longitudinal stitches;' and the
outer concentric portion of cam race 6I oper.
atively engagesroller stud 63 to swing outwardly
in'minimum or reduced throw position whereby
the feed means is actuated at minor amplitude
during the production of the substantially lateral
which stitching comprises alternated straight
run stitches and groups of laterally disposed 55
stitches, the stitches of the latter groups being
.,throw, under which conditions the substantially ~comparatively closely spaced together by means
of the reduced operative amplitude of the mate
lateral `stitches are produced.
The means for producing lateral oscillations of
60 the verticallyY reciprocated needle-bar I1 and its
needle I8 to produce the substantially lateral
stitches under reduced or minimum material feed
conditions,y whereby the desired» stitched pattern
or design effects are produced on the material
65 sewn, comprises a rotary cam wheel 5I, shaft or
spindle 52 of which-is transversely journaled in
the arm I2. ySaid shaft or spindle 52 is actuated
by a Worm-gear 53 fixed on its inner end portion
and adapted to be driven by a worm 54 fixed on
70 drive-shaft I4. Cam wheel 5| is provided in its
fa/ce with a suitably shaped cam groove or Vrace 55.
Pivotally mounted on a bracket 56 associated with
arm |2~is a lever member, the‘upwardly extend
ing arm 51 o_i’ïwhich is providedv with a roller
75 stud 58 operatively engaged in said ycam groove
rial feed means which automatically occurs when
such-stitching is sewn. In this manner patterns 60
or designs with various dotted effects may be ob
tained. The lateral stitches may be closely
spaced by setting the stopiscrew 31, so as to re
duce the throw of eccentric 30 to an amplitude
which Will feed the material sewn but for a dis
tance approximating the width of the thread em
ployed, inwhich case the lateral stitches will form
a more or less solid dot-like formation of em
broidered appearance, such, for example, as
shown in Figs. 6 and 8. On the other hand, the
stop-screw 31 may be adjusted to stop the frame
32 and dispose the eccentric 30 in any selected
position Within the range of its maximum-mini
mum throw, in which case the lateral stitches
may be disposed to form more or less open zig-zag
patterns, such, for example, as shown in Fig. '7;
The peripheral shape of the lateral stitch pro
duced dots or design patterns, is effected by the
specific character of the waved portion of -camrace 55. For example, said cam race portion may
be shaped to progressively increase and then de-crease the lateral oscillatory movement of the
needle bar 'I1 and _needle I8, thus producing dots
or -design patterns of diamond-like -outline, as
shownin Fig. 6; or said cam race p_ortlon may
be shaped to produce uniform oscillatory move
ment adapted tovproduce dots or 'design patterns
.of more orless rectangular> outline,_ as shown in
-1 Fig. 8.. It will be obvious thatïother outline
, ' shapes may also be produced by suitably varying
.the shape 'of the waved portion of cam race 55.
Having thus described-myinvention, I claim:
1. In a sewing machine having a vertically re
means entered in said slot, spring means urging
said frame in one direction in stopped engage
ment with said stud to thereby position the ec
centric for minimum throw adapted to effect min- '
imum amplitude of Vfeed means movement, means 5
to move said frame in'an opposite direction and - '
hold the same against the tension of said spring
to position vthe eccentric for maximum throw
adapted to effect maximum amplitude of feed
means movement, and adjustable means for vary
ing the stud stopped position of said frame and
eccentric to selectively predetermine the scope of
minimum amplitude of feed means movement,
said latter means comprising an adjustable stop
screw carried by said frame to enter an end of
its slot in opposition to said stud.
2. In a sewing machine having mechanism
defined in claim 1, wherein the means to move
ciprocable and transversely oscillatable needle and l 'said frame to dispose said eccentric in. maximum
throw position comprises a plunger slidable in 20
cooperating feed means, mechanism for actuat
ing said feed means for both maximum and mini.l said drive shaft, a thrust pin carried by said frame '
andengageable by said plunger, oscillatable lever
imum- amplitude of yieeding movement compris
ling, a drive shaft, a frame having a feed operat „.mechanism for actuating said plunger. a rotary
ing eccentric, carrier means rotated by said shaft control cam toeiîect timed movements of said
lever mechanism, and~ drive shaft operated trans' 25
to which said frame is pivoted for lateral move
ment relative to said shaft, the free end of said mission for actuating said cam.EMIL PRAZAK.
frame having a slot, a iixed stud on said carrier
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