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Патент USA US2106080

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Jan. 18, 1938.
I
L. G. BOWMAN
2,106,080
SEWING MACHINE WORK SUPPORT
Original Filed Sept’. 27', '1955
:s Sheets-Sheet 2
Louis G. Bowman
as" 3%
Jan. 18, 1938. '
L, G, BQWMAN
2,106,080 ‘
SEWING MACHINE WORK SUPPORT I
Original Filed Sept. 27. 1955
a Sheets-Sheet}
2,106,80
Patented Jan. 18, 1938
" NITED STATES
PATENT OFFICE
2,106,080
SEWING MACHINE WOIRK SUPPORT
Louis G. Bowman, St. Louis, Mo., assignor to
Lewis Invisible Stitch Machine Company, St.
Louis, Mo., a corporation of Maine
Original application September 27, 1935, Serial
No. 42,547. Divided and this application May
5, 1936, Serial No. 78,035
16 Claims. (Cl. 112—~260)
This invention relates to new and useful im
provements in sewing machines generally, al
though more particularly to the work support of
a blind stitch sewing machine.
This application constitutes a division of my
co-pending application Serial No. 42,547, ?led
Sept. 27, 1935, for improvements in Sewing ma~
neath the presser foot 20 as shown in Figures 1
and 2.
A lug I26 depends from the work support M
and to this lug a latch dog I2‘I is pivoted as at
I23. The dog I21 includes an eccentric lock sur
face I29 and a release lug extension I39. The‘
lock surface I29 normally rests on the horizontal .
leg I3I of a bell crank lever pivoted at I32 onthe
chines.
The principal object of this invention is to pro- I frame lug I33, the remaining leg I34 of the bell
10 vide a novel depressible work support and yield
able dual spring mounting therefor whereby a
relatively strong resistance to depression of the
support is offered during normal sewing opera
tions and a relatively weaker resistance to de
15 pression of the support is encountered by an op
erator when inserting a fabric in the machine or
when removing the fabric therefrom.
With the above and other objects in view which
will more fully appear, the nature of the inven
zotion will be more clearly understood by following
the description, the appended claims, and the
several views illustrated in the accompanying
drawings.
In the drawings:
Figure l is a front elevation of a sewing ma
25
chine embodying my invention,
Figure 2 is a top plan view thereof,
Figure 3 is a partial right hand elevation of the
machine, and
,
Figure 4 is a detail vertical sectional view illus
trating the dual spring mounting of the work
support.
Like reference numerals designate correspond
ing parts throughout the several ?gures of the
35. drawings.
My invention is disclosed as being applied. to
a blank stitch sewing machine which embodies a
main frame having a base 5, a standard 6, and
a laterally extending arm ‘I which terminates in
40va forwardly extending stitching head 8. A main
shaft 9 is journaled in the laterally extending
arm ‘I and the upper end of the standard. A hor
izontal presser foot 20 is rigidly attached to the
front end of the forwardly extending head 8. An
45-0scillatory needle 24 and a cooperating stitch
forming mechanism are supported on the head
8 and are operatively connected to the main
shaft 9.
-
A work support or table II is pivotally sup
?oported at 42 on a horizontal shaft 43 supported
in and extending laterally from the frame stand
ard 6 in parallelism with the main shaft 9. The
support III includes an upstanding guard ?ange
portion 44 and a slightly depressed portion 45
crank extending downwardly and engaging a
strong cushion spring I35 seated in a frame sock
et I36. The contact between the leg I34 and
the spring I35 is made by an adjustable abutment
screw I3'I.
By reason‘v of the direct contact between the
parts I29, I31, I31, I35 downward movement of
the work support 4| is strongly resisted by the
spring I35 and the tendency of the spring I35
to force the support upwardly is suitably resisted
by an adjustable stop screw I38 threaded through 20 the guard wall 44 and abutting a stop I39 se
cured on the frame standard. By provision of
this equipment a downwardly yieldable work sup
port is provided and yet the spring I35 is much
too strong to permit undesirable downward move
ment thereof.
When it is desired to lower the support M to
insert or remove the work, the operator should
not be subjected to the severe labor and strain
necessary to oppose the relatively stronger spring 30',
I35 and for this reason I have provided arela
tively lighter spring and means whereby the
strong spring may be rendered ineffective and
the weaker spring brought into play simultane
355'
ously with the effort of lowering the support.
It will be observed by reference to Figure 4
that a coil spring I40’ connected to the support
all and the dog I21 serves normally to retain‘ the
dog in the position illustrated in Figure 4. , The
relatively weaker spring above referred to is in 40,
the nature of a coil spring IIII» coiled about the
stud I42 projecting from the frame lug I33 and
having one end thereof anchored as at I43 to
the frame and the other end I 44 engaging un
der the work support. 4| as shown in Figure 4. A
trip lever v I45. is pivoted intermediate its ends as
at I46 to a lug depending from the support 4|.
One end of the lever projects under the release
lug I30 and to- the remaining end a pull chain
I4‘! is secured. By pulling downwardly on the
chain I41 the dog I21 will be tripped to the posi
tion illustrated in. dotted lines in Figure 4, thus
releasing the support 4 I- from the in?uence of the
relatively stronger spring I35 and permitting the
55 .
aswhich extends laterally from said support be-V operator tolower the support by use of the chain.
2
2,106,080
l4‘! resisted only by the relatively weaker spring
sion, means including a relatively weak spring
for retaining the support against depression
I4]. Upon release of the chain the spring I40
will return the dog I31 to the position illustrated
in full lines in Figure 4, the eccentric surface I29
facilitating the return to normal engagement with
the bell crank leg l3l.
The strong spring I35 is essential to the at
ineffective, and means for ?rst rendering said
normally effective/‘means ineffective and for
tainment of even needle penetrations because the
needle travels in a ?xed path and consequently
10 the same depth of the ridge of material must be
4. In a sewing machine, the combination of a
depressible work support, means including a rela
15
20
25
30
always presented to the needle. Thus in the
formation of “anchor” stitches it is necessary
that the ridge forming element rise to the same
high position in relation to the needle, and the
work support which carries the element must be
substantially rigid when heavy seams are en
countered. The resistance to upward movement
of the element must not be solid, however, be
cause if the element could not push the mate
rial up through the opening in the presser foot
something must yield or break. The spring I35
provides the desirable strong yet yieldable re
sistance.
When the operator desires to insert work, a
slight pull on the chain I41 will release the
toggle I45, I21. With the parts in this position
the light spring MI alone is effective to hold the
work support against depression and only a
slight force is necessary to be exerted by the
operator to depress the work support 4| sul?
ciently for inserting the work under the presser
foot, or removing work therefrom. In this man
ner the depression of the work support or table
4| may be said to- be opposed by a primary means
and a secondary means of varying degree, and
that said means may be rendered selectively
dominant.
A stop screw I48 is provided to maintain a
working contact between the cam surface of
40 the latch dog I21 and the nose of the leg l3l of
the bell crank lever.
It will be seen that the lock surface I29 of the
latch dog I21 and the leg I 3| of the bell crank
lever, constitute a means which includes thrust
45 applying and releasing elements which are
changeable in relation from depressive thrust
applying position as shown in Fig. 4 by the full
lines, to depressive thrust releasing position as
shown in Fig. 4 by the dotted lines.
50
It is of course to be understood that the details
of structure and arrangement of parts may be
variously changed and modi?ed without depart
ing from the spirit and scope of my invention.
I claim:
55
1. In a sewing machine, the combination of a
depressible work support, means for imposing
upon the support a primary degree of resistance
to depression, means for imposing upon the sup
port a secondary degree of resistance to depres
60 sion, and means for rendering said primary and
secondary resistance imposing means selectively
dominant.
2. In a sewing machine, the combination of a
depressible work support, normally effective
65 means including a relatively strong spring for
yieldingly retaining the support against depres
sion, means including a relatively weak spring
for retaining the support against depression when
said normally effective means is rendered ineffec
70 tive, and means for rendering said normally effec
tive means ineffective.
3. In a sewing machine, the combination of a
depressible work support, normally effective
means including a relatively strong spring for
75 yieldingly retaining the support against depres
when said normally effective means is rendered
thereafter depressing the support against the
tension of the weaker spring.
tively strong spring for imposing upon the sup 10
port a primary degree of resistance to depres
sion, means including a relatively weak spring
for imposing upon the support a secondary degree
of resistance to depression, and means for render
ing said primary and secondary resistance im
posing means selectively dominant.
15
5. In a sewing machine, the combination of a
frame including a stitching head, a stitch form
ing means including a reciprocable needle mount
ed on the head, a depressible work support mount 20
ed on the frame and disposed below said head,
means for imposing upon the support a primary
degree of resistance to depression, means for im
posing upon the support a secondary degree of
resistance to depression, and means for rendering 25
said primary and secondary resistance imposing
means selectively dominant.
6. In a sewing machine, the combination of a
frame including a stitching head, a stitch forming
means including a reciprocable needle mounted 30
on the head, a depressible work support mounted
on the frame and disposed below said head, nor
mally effective means including a relatively
strong spring for yieldingly retaining the sup
port against depression, means including a rela
35
tively weak spring for retaining the support
against depression when said normally effective
means is rendered ineffective, and , means for
?rst rendering said normally eifective means in
effective and for thereafter depressing the sup
port against the tension of the weaker spring.
7. In a sewing machine, the combination of a
frame including a base, a standard, and an over
hanging arm; a stitching head carried by the
arm; stitch forming means including a recipro 45
cable needle; a depressible Work support pivotally
supported on said standard and extended beneath
said head; normally effective means including a
relatively strong spring for yieldingly retaining
the support against depression; means including 60
a relatively weak spring for retaining the sup
port against depression when said normally effec
tive means is rendered ineffective; and means
for rendering said normally effective means in
effective.
66
8. In a sewing machine, the combination of a
frame including a base, a standard, and an over
hanging arm; a stitching head carried by the
arm; stitch forming means including a recipro
cable needle; a depressible work support pivotally 60
supported on said standard and extended beneath
said head; normally eifective means including a
relatively strong spring for yieldingly retaining
the support against depression; means including
a relatively weak spring for retaining the sup 65
port against depression when said normally ef
fective means is rendered ineifective; and means
for ?rst rendering said normally effective means
ineffective and for thereafter depressing the sup
port against the tension of the weaker spring.
70
9. In a sewing machine, the combination of a
depressible work support, means including thrust
applying and releasing elements changeable in
relation from depressive thrust applying to de
pressive thrust releasing position for resisting or 75
3
2,106,080
permitting depression of the support, light spring
means for resisting depression of the support
when said elements are in thrust releasing posi
tion, and means to move said elements.
10. In a sewing machine, the combination of a
depressible work support, means including thrust
applying and releasing elements changeable in
relation from depressive thrust applying to de
pressive thrust releasing position for resisting or
10 permitting depression of the support, light spring
means for resisting depression of the support
when said elements are in thrust releasing posi
tion, and means for changing the relation of said
elements to negate their resisting function and to
15 depress the support against the tension of said
spring to change their relation.
11. In a sewing machine, a frame, a depressible
support mounted on the frame, a relatively strong
spring, make and break thrust connections in
terposed between the strong spring and the sup
port to normally offer strong yieldable resistance
to depression of said support, means to break the
connections and the strong resistance to depres
sion of the support, and a weak spring effective
25 to resist depression of the support when said con
nections are broken.
12. In a sewing machine, a frame, a depressible
support mounted on the frame, a relatively strong
spring, a thrust lever pivoted to the frame and
30 engaging the strong spring, a thrust link pivotal
ly supported on the support and movable into
and out of engagement with the lever to respec
tively impart depressive thrusts to the lever and
the strong spring or to relieve the support of the
resistance of said strong spring, and a weak spring
effective to resist depression of the support when
the link and lever are disengaged.
13. In a sewing machine, a frame, a depressible
support mounted on the frame, a relatively strong
40 spring, a thrust lever pivoted to the frame and
engaging the strong spring, a thrust link pivotally
supported on the support and movable into and
out of engagement with the lever to respectively
impart depressive thrusts. to the lever and the
45 strong spring or to relieve the support of the
resistance of said strong spring, a weak spring
effective to resist depression of the support when
the link and lever are disengaged, and means
for moving the link out of engagement with the
lever and for depressing the support.
14. In a sewing machine, a frame, a depressible
support mounted on the frame, a relatively strong
spring, a thrust lever pivoted to the frame and
engaging the strong spring, a thrust link pivotally
supported on the support and movable into and
out of engagement with the lever to respectively
impart depressive thrusts to the lever and the
strong spring or to relieve the support of the re 10
sistance of said strong spring, a weak spring ef
fective to resist depression of the support when
the link and lever are disengaged, means for mov
ing the link out of engagement with the lever 15
and for depressing the support, and means to
automatically restore link and lever engagement
when the depressing force on the support is re
leased.
.
15. In a sewing machine, the combination of a 20
depressible work support, means for imposing
upon the support a primary degree of resistance
to depression, means for imposing upon the sup
port a secondary degree of resistance to depres
sion, means for rendering said primary and sec
25
ondary resistance imposing means selectively
dominant, and adjustable means cooperating with
said primary resistance imposing means for ad
justing the extreme upward limit of movement
of the work support.
30
16. In a sewing machine, a frame, a depressible
support mounted on the frame, a relatively strong
spring, a thrust lever pivoted to the frame and
engaging the strong spring, a thrust link pivotally
supported on the support and movable into and 35
out of engagement with the lever to respectively
impart depressive thrusts to the lever and the
strong spring or to relieve the support of the
resistance of said strong spring, a weak spring
effective to resist depression of the support when 40
the link and lever are disengaged, means for mov
ing the link out of engagement with the lever and
for depressing the support, and means for limit
ing freedom of movement of the lever during dis
engagement of said lever and link.
45
LOUIS G. BOWMAN.
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