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Патент USA US2110650

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March s, 1938.
'
-
F. A.‘LARSONI
_
2,11%50
SHOE SEWING MACHINE
Filed Jan. 18, 1956
5 Sheets-Sheet l
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64 62 9.5:
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March 8, 1938.
F. A. LARSON
2,1 11,650
‘SHOE SEWING MACHINE
' Filed Jan. 18, 1936
5 Sheets-Sheet‘ 2
March 8, 1938.
F, A; LARSON
2,110,650
SHOE SEWING MACHINE
Filed Jan. l8, 1956
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5 Sheets-Sheet 3
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F A. L A R S O N
2,110,650
SHOE SEWING MACHINE
Filed Jan. 18, 1956
5 Sheets-Sheet 4
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March
193.
F, A LARSON
2,110,650
SHOE SEWING MACHINE
Filed Jan. 18, 1936
‘
5 Sheets-Sheet 5
Patented‘ Mar. 8, 1938
‘
2,1
UNITED STATES PATENT QFFIQE
2,110,650
,SHOE SEWING MACHHNE
Frank A. Larson, Saugus, Mass.
Application January 18, 1936, Serial No. 59,723
20 Claims. (Cl. 112-”8)
This invention relates to sewing machines, and die, needle guide, aw], and loop-spreader mo
more particularly to lock stitch, curved hook neetion,
dle machines such as are commonly employed for
securing the outsoles to boots and shoes.
In
Figure 6 is a plan view of the mechanism of
Figure 5,
5 machines of this kind, owing to the fact that the
Figure 7 is a sectional detail on line 7-1 of
several operative instrumentalities require to
have variable quick and slow movements and
dwells between movements, it has heretofore been
Figure 5,
Figure 8 is. a detail elevation of the needle,
needle guide and awl motion, showing the origin
deemed necessary to employ numbers of cams
10 or equivalent devices, and special gearing ar-
rangements, all of which have produced a large
5
of the motion from the main shaft,
Figure 9 is a detail elevation of the loop- 10
spreader motion,
complement of friction and consumption of
power and hence machines so constructedohave
required considerable power to operate them so
15 that they are impracticable or dii?cult for manual operation as well as involving rapid wear of
the parts and causing vibrations in the machine.
Figure 10 is a detail elevation of the shuttle
motion showing its origin from the main shaft
of the machine,
Figure 11 is a detail elevation of the take-up i.
lever motion showing its origin from the main
shaft,
The prime object of the present invention is
to produce amachine of the kind stated wherein
‘20 substantially all of the requisite movements are
imparted to the usual or necessary instrumentalities of such a machine by special and novel arrangements of links and levers from a common
rive shaft. In accordance with my invention,
'25 such system of links and levers are arranged
and adapted to produce all of the varied fast
and slow change movements and dwells of the
operative parts of the machine. By thus substantially eliminating friction producing tranSmission such as cams and special gearing, I
make the machine very much easier to operate
and so that it can be readily operated by manual
power if desired. The invention also compre-
Figure 12 is a detail elevation showing the.
looper motion with its origin from the main
shaft,
20
Figure 13 is a detail elevation showing the
loop~control arm, or loop-hook and the operating
means thereof,
Figure 14 is a detail of the feeding mechanism
showing its origin from the main shaft, and
25
Figure 15 is a detail view looking in the direc
tion of the arrows from the line |5—i5 of Fig‘
me 14.
All of the operative means to be described are
derived from a main shaft l journaled in the 30
base portion of a suitable machine framework
la. Such operative movements will now be sev
erally described:
hends certain special improvements in the oper-
,
35 ative instrumentalities as will be later described.
The foregoing and other objects and advan—
tages of the invention will be better understood
from the following detailed description taken in
connection with the accompanying drawings, and
40 the distinctive features of novelty will be there—
after pointed out in the appended claims,
Referring to the drawings:
Figure l is a side elevation of a machine embodying my invention with parts broken away in
section’
.
I"_'Looper and zoop'hook mono”
Referring particularly to Figures 12 and 13,
the looper and loop-hook motion is derived from
the main shaft l through a crank arm 2 on the
main shaft 5 which oscillates a horizontal shaft
a through a connecting link 4 and upright arm 40
5 which is pinned to shaft 3. Oscillating with
shaft 3 is a small upright arm 6. Pivoted to this
afm is 8' link 7 which operates thmugb three
links 8, 9 and ill to e?fect oscillating motion in a
gear segment H, and to turn angear l2 which is 45
Figure 2 is a side elevation from the opposite
?xed tof tile §hli7ftqof 100p er 1a‘. The aria‘ngo'
side of the machine to Figure 1, showing essen-
went 0? t e "m s ’ 8’ g and a 1.8 .Such t at ?“s
tial portions of the improved link and lever ar_
59 langementsi
_
_
,
_Flgure 3 ‘s c?” partial plan ‘new showmg par’
“Gummy the lmkage arrangement of Figure 2,
Figure 4 is a partial end View 100king in the
direction 0f the arrows 4-4 of Figure 2,
5En
Figure 5 is a detail elevation showing the nee-
~10 UK
me
am shaft “Wis from lt-s position’ shown- I?
Figure 12, towards its oppos1te extreme position
for this motion, shown in dot and dash lines in 50
the same ?gure, during the ?rst part of such
movement the looper remains without motion
or an extremely small amount of motion, this
being during a period of time in which the main
shaft has rotated to a position shown in Figure 55
2,110,660
2
III.--Loop-spreader motion
8 when the needle I4 is down through the work.
Then while the main shaft I moves from its
position shown in Figure 8 to the extreme posi
tion of Figure 12, a direct downward pull on the
5 link it through links 1, 8 and 9 aifords a quick
rotary motion to the looper l3 which casts the
motion is taken from the needle clamp arm
through a link 21% pivoted thereto at one end
thread about the needle barb, according to usual
practice. It will be understood that the de
tates to a. position shown in dot and dash lines
scribed movement results because starting from
the full line position shown in Figure 12, the
downward movement of the link ‘i to straighten
the toggle links 8 and 9 operates through the
link 9 upon the link ll] approximately at right
angles thereto giving it very little movement,
a position shown in dot and dash lines in Figures 10
8 and 9 which in turn draws the toggle links 25,
2E downward, rotating shaft 28 by means of the
universal link 2'! secured to said shaft. Being
fastened to shaft 28 the loop-spreader 29 re
ceives an upward swing shown in dot and dash
lines in Figure 9 at the same time that the shaft
28 receives its rotating motion. It will be noted
that the arrangement of links 24, 25 and 26 is
similar to that of links ‘I, 8, 9 of the looper mo
tion, and affords to the loop~spreader a quick 20
motion after a dwell, similar to that given to
the looper.
it being noted that the arm 5 is then in a posi
tion to impart least movement to the link 1.
After the parts are moved downward past the
straightened position of the links 8 and 9, the
link 9 is then pulling downward relatively close
20 to the turning axis of the link It causing the
link it and hence the looper to receive a rela
tively much increased movement in the last part
of the downward pull of the links ‘I and 9. It is
As best seen in Figure 9, the loop-spreader
and having its other end pivoted to a pair of
toggle links 25, 25. When the main shaft ro
in Figure 8, the needle clamp arm is brought to
to be further noted that the degree of this dif
25 ferential movement is further accentuated by
the relative arrangement of the arms 5 and 6
upon the shaft 3.
From the same connections, movement is taken
to operate the loop-hook H‘: as seen in Figure 13.
30 This loop-hook I5 is fulcrumed on the main
frame in proper relation to the looper l3, as
shown in Figure 2, and is operated by a bell crank
arm it through a link H which is fulcrumed to
the stud l8 which is a connecting stud for links
35 1, 8 and 9. The motion given to this loop-hook
is a uniform motion. While the system of links
and levers for actuating the active instrumental
ities of my invention is of value and importance
for operating elements such as the loop-hook l5
which has a relatively uniform motion, such sys
tem is of particular value for operating those
instrumentalities which require -to have a quick
operative movement with a slow movement or
dwell between operating movements as above
45 described for the looper. For the other operat
ing elements to be now described, I employ link
age including toggle link systems generally simi—
lar to the link system ‘I, 8 and 9 and which obtain
the required movements without the use of fric
tion creating gears and cams.
II.—NeedZe motion
The needle motion as best seen in Figure 8, is
taken directly from the main shaft l by means
55 of an extension of the crank arm 2 carrying stud
l9 to which is pivoted needle lever 20, which op~
erates the oscillating needle holder 2|, an awl
carrier 21a, and the needle guide 22. The link
23 connecting the needle lever 20 affords the
needle guide its proper timing. To adjust the
needle guide position in relation to the needle
barb, an eccentric or like means 22a may be ap
plied to the connecting stud at one end of the
link 23. The needle motion which is given to the
65 needle holder H is transmitted to the awl carrier
by a dowel pin Zlb fastened to the awl carrier
Bid and working loosely in a hole in the needle
holder or clamp 2|. This allows the awl carrier
to move laterally for feeding the work while being
70
turned by the dowel pin 2 lb. As later more fully
explained, provision is made for changing the
rate of such work feeding movement of the awl
carrier while the machine is in operation and
75 the needle holder in movement.
IV.—Shuttle motion
As best seen in Figure 10, pivoted to the stud 25
I53 which, as stated is carried by an extension of
crank arm 2, is a link 30 attaching to a crank
arm 3! pinned to a shaft 32 journalled in the
machine frame. Owing to the link connection
from one crank to the other, the motion given 30
to shaft 32 is an uneven fast and slow’ motion al
ternating during each revolution. From this mo
tion is taken the shuttle motion shown in Figure
10 and to produce such motion with the proper
timing a crank arm 33 is pinned to the shaft 32. 35
On this crank arm 33 a link 34 extending angu
larly thereto is pinned to stud 35 carried by the
crank arm 33, and an oscillating motion is trans
mitted to a shaft 36 fulcrumed in the main frame
by a connecting link 31 from the link 35 to the 40
crank arm 38 ?xed on a shaft 36.
The neces
sary oscillating shuttle motion is taken from the
crank arm 38 by a connecting link 39 through a
gear segment and gear 40, 4| and a bell crank
arm 42 and thence to the shuttle housing 43.
45
V.-Thread tension control
As best seen in Figure 2, a positive thread
tension control arm 64 has an arm 45 extending
obtusely rearward therefrom,’ these two arms
being in one and constituting a bell crank lever
fulcrumed to the machine frame. From the
arm 45 a link 46 extends to a short crank arm
41 pinned to the oscillating shaft 36 which con
stitutes a part of the shuttle motion as described. .
The arm 44 carries at its extremity a small roller
6.8 over which the thread T passes, the motion
which this roller receives being such, that while
the usual thread tension spring may be em
ployed, the thread is kept taut at all times with 60
out being placed under a breaking strain, with
out the aid of the'ordinary tension spring. In
regard to this motion it will be noted that at the
time the toggle arrangement 'l-8-—9 operates on
link IE, moving loop-hook l5 rearward carrying 65
with it the thread T, the arm 44 moves downward
giving to the loop-hook the necessary amount of
thread, and continues to move downward as the
looper l3 casts the thread about the needle barb
thereby giving to the looper its proper length of
thread. At this point the loop spreader 29 takes
the thread to cast it about the shuttle while the
takenup arm ‘M (to be presently described) gives
the necessary amount of thread, and while the
take-up returns to its downward position tak 75
3
2,110,650
ing-up the surplus thread in making the stitch,
the positive-thread tension control arm 44 also
returns to its normal upward position. The ac
tion of the two levers lit and M working in op
posite directions at the crucial moment when the
stitch is being made insures a good tight stitch.
Cooperating with this mechanism an automatic
thread measuring device (to be presently de~
scribed) aids in obtaining a tight and even stitch.
10
15 from link 59 to arm 5! which is pinned to a stud
52 fulcrumed in the machine frame, gives an
oscillating motion to the cam 53 which is also
pinned to the stud 52. A forked lever 5t ful
crumed in an adjustable housing 55 receives a
20 rocking motion which is transmitted as an os
cillating motion to shaft 5t‘ through universal
connecting links M, 53. Pinned to the shaft 53
is a forked link 59 which straddles a pin 5Q pro
jecting from a hollow shaft 6| giving it a re
ciprocating motion which is thus given to an
adjustable pin 62 held in hollow shaft 6! by
suitable clamping means as seen at 653.
Fas
tened to this pin 62, is a yoke 64 which straddles
the awl carrier 2la giving to it the described
30
reciprocating motion for feeding the work, it
being understood that the present machine is of
that type wherein the work .is fed by a lateral
movement of the awl while engaged through the
Work. To obtain an adjustment for aligning
35
the awl with the needle, the yoke 64 is secured
to the pin 62 by a shouldered screw 65 allowing
the pin 62 to be turned. This pin carries a
threaded portion that screws into the hollow shaft
Bl, which has an internally threaded portion for
40 this purpose, and by turning the pin 62 by its
knurled head 65, the awl can be moved laterally
for the necessary adjustment. The feeding cam
53 is so located on stud 52 that the proper dwell
and feeding motion is obtained with the assist
45
ance of the linkage 49, 50 and 5E. The arrange
ment of these links is also similar to that of the
links l, 8, 9 of the lo-oper motion, and affords
a quick feeding motion.
50
The amount of feed
is governed by changing the fulcrum point of
the forked lever 54 by moving the housing 55
which carries this fulcrumed point along the
horizontal shaft Bl carried in the machine frame,
by use of the handle 68, as seen in Figure 1, which
55 is fulcrumed to the frame at 59, and connected
to housing 55 by link “iii. It is thus possible
to change the amount of feed, i. e., the spacing
of the stitches while the machine is in opera
tion by operating the handle 68.
60
VII.-_-Take-up motion
As best seen in Figure 11, the take-up motion
is derived from the stud 35 on the crank arm 33
pinned t6 the shaft 32 which is s' pplied with an
65 uneven and alternating fast and slow motion as
previously described. Pivoted at one end to this
stud 35 a link ll connects to a bell crank ‘it
fulcrumed on the shaft
A connecting link
13 connects the arm l'Za of this bell crank to
the take-up lever ‘it which is fulcrumed to the
machine frame at T5. The lever if: bears at its
extremity a small roller life around which the
thread T passes from the tension roller 4-8 to
75 the shuttle and needle mechanism.
to the bell crank ‘H is a link 89 carrying a cam
roll ill, which cam roll is also connected to, and 10
under the control of, a link I05 to be later further
VI .~Feedz'ng motion
As best seen in Figure ill, the feeding motion
is also controlled by the shaft 35. Pinned to
this shaft is a link 459. A connecting link 5t
25
VIIl.—Presser foot mechanism
As best seen at Figure 2, the presser foot
mechanism derives its movement from the stud
‘it which is the connecting stud for the take-up
bell crank 72 and its connecting link ‘H. The
motion of this bell crank is transferred to an-.
other bell crank ll fulcrumed to the machine
frame at it, by a connecting link 79. Attached
described.
This cam roll operates in a cam
slot in a lever 82 which is fulcrumed to the
machine frame at 33. Attached to this lever
$12 by stud 8d is a block 85 adapted to slide in a
frame or housing 86. This frame 86 is attached
to a presser foot lever 8i” fulcrumed on the ma
chine frame at I38. Two locking pins 39, 90 held
in wedge shaped grooves in the slide block 85
by ?at springs Hi, 92, lock the slide block 35 in
its frame 8E causing the frame and block to
move as one unit.
After the cam lever 82 has
been forced downward by the action of the cam
roll 8| in the cam slot, thus raising the presser
foot 93, the flat faces of the cam lever 82 shown
at M, 95 come to such an angle as to act against
the rollers 96, 91 borne by the ends of locking
pins 89, 98, causing the locking pins to release
the slide block 85, this constituting a self-disconnecting device which then allows the spring
98 to act on the presser foot lever 81 through
lever 99, fulcrumed at 9911 and engaging the
presser foot lever at 9919; thus moving the press
er foot down to operative position. The presser
foot can also be operated manually by handles
it'll, Elli. Handle liil effects the release of lock
ing pins 39, 98 through the toggle links “if, "it
connected thereto by link Hill, which links are
connected at one end to the machine frame and
at their other end to the rocking lever Hi5 whiclr 40
through a link I96 is connected to the cam roll
er 8!. The handle loll which is fastened to the
presser foot lever may be used to lift the presser
foot.
IX.-Automatic thread measuring device‘
45
As best seen in Figures 1 and 2, a mechanism
is employed to automatically measure and take
from the spool the amount of thread to be used
in making each stitch. As the amount of thread, 50
necessary, varies with the thickness of the ma
terial which is being stitched, the device is con
trolled by the presser foot 93 which bears on the
work, continually acting as a caliper. Pinned
to the extremity of shaft Sii-a is an arm I01 with
a projecting pin E88. Fulcrumed in the machine
frame at “it, an arm H0 is held against the pin
E68 by spring Hi fastened to the frame. In
the underside of arm lit; a screw H2, which
may be felt capped, is in position to be contacted 60
by the bell crank arm 72a of hell crank 12 in its
upward travel. A spring H3 is fastened to arm
lie. The thread comes from the spool and is
temporarily gripped between the pin H18 and
underside of arm Hi3; it then passes through a 65
hole in arm it? for controlling purposes and
thence up and under spring H3 where it is per
manently, gently gripped by spring H3 bearing
down on it. Thence it continues to the wax pot,
up over the positive-thread-tension control arm 70
roller 138, thence to the take-up arm roller ‘Ida, ‘
and on to the looper l3. As the bell crank arm
‘52a travels in its upward motion, it strikes
against the screw H2, which may be adjusted
in or out, raising arm ill} from its resting posi 75
4-
2,110,650
tion on pin “it. As thread is being gripped at
this point, it will be noted that as the arm H0
is raised, the thread is immediately released, and
being permanently gripped by spring ! l3 attached
Cl
to arm Me, an amount of thread is drawn from
the spool which is governed only by the amount
of lift that is transmitted to arm HQ.
As the
needle mechanism including an oscillating needle
holder, connected to be operated from such drive
shaft, such connection to the needle holder em
bodying a crank on the prime drive shaft, an
arm extending from the needle holder and a
direct link connection from said crank to said
arm.
5. A look stitch sewing machine as described
bell crank arm ‘E20, moves to its downward posi
tion returning arm lid to its gripping position
in claim 4 having an oscillating needle guide with
ii) on pin I83, the amount of thread drawn from
operates the needle holder arranged to impart
the spool rests in loop form on the forward side
of pin i118, ready to be used for the coming stitch.
As the presser foot is raised or lowered, it will
be noted that shaft 98a is oscillated which in
turn raises or lowers the contacting pin Hi8
thereby governing or determining the amount of
lift which is to be given to arm Hi? and conse
quently controlling the amount of thread neces
sary for the stitch in the thickness of work on
which the presser foot rests. It will be noted
that at the time the arm 54 and arm 14 are work~
ing against each other to draw the stitch tight,
that the action of the thread on arm iill is such
that it is pulling it downward on pin H38 thereby
tending to grip the thread harder, the tighter
the stitch is being drawn.
Certain other features of, or accessories to, a
complete lock stitch sewing machine such as a
heated wax pot for coating the thread, are not
30 herein shown or described since they form no
part of the present invention and have no novel
cooperative relation with the features shown and
claimed herein.
I am aware that the invention may be em
35 bodied in other speci?c forms without depart
ing from the spirit or essential attributes there
of, and I therefore desire the present embodi
ment to be considered in all respects as illus
trative and not restrictive, reference being had
40 to the appended claims rather than to the fore
going description to indicate the scope of the
invention.
Having now- described my invention, what I
claim as new and desire to secure by Letters
45 Patent is:
1. A look stitch sewing machine comprising
awl and needle mechanism, shuttle mechanism,
work feeding mechanism, a prime drive shaft
with connections to all of said mechanisms to
operate the same, and a looper equipped with
rotating means, said rotating means having a
direct link and lever connection to the prime
drive shaft embodying a plurality of cooperative
toggle devices, one working through another and
55 arranged to impart very quick operative move
ments to the looper rotating means with rela
tively long dwells between such movements.
2. A look stitch sewing machine comprising a
prime drive shaft having connections to operate
60 all the operative instrumentalities of the machine,
embracing a looper equipped with rotating means,
said rotating means directly connected from the
prime drive shaft by a crank on such shaft, a
link from such crank, a bell crank connected to
' such link, a second link and a toggle device con—
nected to the second link and to the looper ro
tating means arranged to impart to the looper
quick operative movements with dwells between
such movements.
3. A look stitch sewing machine as described
in claim 1 having a loop hook with a link con
' nection to the toggle device to be operated in
connection therewith.
1i. A look stitch sewing machine'comprising
75 a prime drive shaft, a work feed, and awl and
a link connection to an extension of the link which 10
a differential movement to the needle guide with
respect to that of the needle holder.
6. A look stitch sewing machine comprising
awl and needle mechanism, work holding and 15
work feeding mechanism, a single drive shaft
connected to operate all of said parts and hav
ing a direct link and lever arm connection to the
needle holder to oscillate the same, and a loop
spreader having a linkage connection to the 20
needle holder embodying a toggle link device
arranged to impart quick operating movements
to the loop spreader with intervening dwells.
7. A look stitch sewing machine as described
in claim 6 wherein the loop spreader is mounted
to turn about an axis at an angle to the axis of
the needle holder with a universal joint con
nection thereto from said toggle link device.
8. A look stitch sewing machine comprising awl
and needle mechanism, a work feed, an oscillating 30
shuttle, a single drive shaft for all of said parts,
and a link and lever system directly connected
with both said shaft and said shuttle to turn
the shuttle, arranged to impart quick operative
movements to the shuttle with a dwell between 35
such movements.
9. A look stitch sewing machine as described
in claim 8 wherein the connections from the
prime drive shaft to the shuttle embrace a sec
ond shaft mounted in offset parallel relation to 40
the prime drive shaft with a link and lever arm
connection from one to the other arranged to
impart an irregular alternating fast and slow
movement to the second shaft, and with a link
and lever connection from said second shaft to 45
the shuttle adapted to accentuate such irregular
motion to impart to the shuttle quick operative
movements with a dwell therebetween.
10. A look stitch sewing machine as described
in claim 8 wherein the connections from the 50
prime drive shaft to the shuttle embrace a sec
ond shaft mounted in parallel offset relation
with respect to the prime drive shaft with a
longer crank on the prime drive shaft connecting
through a link with a shorter crank on the sec
55
ond shaft to impart irregular alternating fast
and slow movements to the second shaft, and a
link and lever arm connection from the second
shaft to the shuttle arranged and adapted to in
crease the extent of such irregularity of move
60
ment to impart quick operative movements to the
shuttle with dwells between such movements.
11. In a lock stitch sewing machine a single
prime drive shaft connected to actuate all the
operating instrmnentalities of the machine, a 65
shuttle, and a toggle link system of connections
from said shaft to the shuttle arranged to op
erate the same with quick operating movements
and a dwell between such movements.
12. In a lock stitch sewing machine having awl 70
and needle, shuttle, and work feed mechanisms,
a prime drive shaft for operating all said mech
anisms, connections from said shaft to the shut
tle including a toggle link system and a shaft
36 for imparting quick operative movements to 75
2,110,650
the shuttle with a dwell between such move
ments, and a thread tension control device em
bracing a bell crank lever having a link and
lever arm connection to said shaft 36 to be actu
ated thereby.
13. A look stitch sewing machine comprising a
prime drive shaft, awl and needle mechanism
with the awl borne in an awl carrier, shuttle
mechanism, and work feed mechanism, embrac
10 ing a linkage system including a toggle device
from the prime drive shaft to the awl carrier
arranged to impart quick operative movements
to the awl carrier with dwells between such
movements.
14. A machine as described in claim 13 where
15
in the connections from the prime drive shaft to
the awl carrier include valso a lever mounted to
turn ‘on a fulcrum, said fulcrum having adjust
ment endwise of. said lever for varying the rate
20 of feed at will while the machine is in operation.
15. In a lock stitch sewing machine a prime
drive shaft, a shuttle, a linkage system for turn
ing the shuttle from said prime drive shaft con
structed and arranged to impart quick operative
movements with a dwell between such move
ments to the shuttle, said linkage system em
bracing an oscillating shaft 36, an awl carrier,
and means for reciprocating said awl carrier
from the shaft 36 embracing a’ toggle device
30
adapted to impart quick operative movements to
the awl carrier with dwells between such move
ments and embracing also a lever having a ful
5 V
from said second shaft, said link and lever con
nections arranged and constructed to partake of
the fast and slow movements of said second shaft
to impart quick operating movements to said
take-up device with dwells between such move
ments.
'
, 17. In a lock stitch sewing machine a prime
drive shaft, a thread take-up device, and a link
age system direct from said prime drive shaft
to said take-up device embracing a plurality of 10
cooperative toggle devices arranged in series with
one working through another constructed and
arranged to transmit and transform uniform
movements of the prime drive shaft as quick
operating movements of the take-up device with 15
dwells between such movements.
18. A look stitch sewing machine comprising a
prime drive shaft, feed mechanism, awl and
needle mechanism, and shuttle mechanism con
nected through toggle link connections to be
actuated therefrom with quick operating move
ments and dwells between such movements, and
a presser foot connected to partake of such quick
operating movements with a self-disconnecting
device interposed in such connection arranged to 25
come into operation as the presser foot is lifted
to a pre-determined degree, with spring means
for thereafter depressing the presser foot to
operative position.
19. An apparatus as set forth in claim 18 30
equipped with manual means for lifting the
presser foot and with cooperative manual means
crum adapted for adjustment while the machine
is in operation to vary the rate of feed.
for rendering said disconnecting device operative.
16. A look stitch sewing machine comprising
a prime drive shaft, awl and needle, shuttle, and
work feed mechanisms connected thereto, such
prime drive shaft, shuttle mechanism, awl and 35
needle mechanism, and feed mechanism with
connection to the shuttle including a second
shaft mounted in parallel o?set relation to the
40 prime drive shaft with means for turning it with
an irregular fast and slow movement with re
spect to the prime drive shaft, and a thread
take-up device comprising a bell crank lever
having link and lever connections to operate it
20. A look stitch sewing machine comprising a
connections from the prime drive shaft to each
of the said mechanisms, each of. said connections
embodying a linkage system including a toggle
device adapted to impart quick operating move 40
ment to its operated element with a dwell be
tween such movements.
FRANK A. LARSON.
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