IMPROVEMENTS IN SEWING-MACHINES
Year: 1884

page_text: COMPLETE SPECIFICATION:
I, JOHN HENRY JOHNSON, of 47 Lincolns-Inn-Fields, in the County of
Middlesex, Gentleman, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN SEWING-MACHINES," and in what manner the same is to be
performed to be particularly described and ascertained in and by the following
statement:
This Invention relates to sewing-machines; and more especially to machines with
rotary hook, and the improvements consist: in the means employed for preventing
the loop of the upper thread from coming in contact with the oiled rim of the case
of the under-thread spool; for facilitating the passage of the said loop around the.
spool-case; for regulating the tension of the under-thread;. for preventing the
driving-strap from being thrown off the pulleys when the machine is turned over.
on its side; for adjusting the length of the stitch; for lubricating the bearing
surface of the spool-case, and for winding thread on the under spool.
The Invention is represented on the annexed two Sheets of Drawings: Figs. 1,
2 and 3 are front views of the spool-case and the rotating disk with a portion of
the cloth-plate, the movable parts being shown in the different Figures in different
positions. Fig. 4 is a side-view corresponding to Fig. 2.. Fig. 5 is a section on
line xx of Fig. 1. Fig. 6 is a back view of the spool-case with section of the
rotating disk on line y y Fig. 4. . Figs. 7.and 8 represent the spool-case and the
under-thread spool in perspective views. Fig. 9 is a sectional view of a machine
showing the rotating disk with spool-case and the arrangement for winding thread
on the under-spool. Fig. 10 is a perspective view of the under-thread spool-case
with rotating disk and contiguous parts. Fig. 11 shows in a like view a modified
arrangement of an under-thread tension. Fig. 12 is a perspective view of the
stitch-regulating device and other parts. Fig. 13 is a back-view and Fig. 14 a
perspective view showing the mode in which the driving-strap is guided, the
machine being in upright position. Fig. 15 is a view representing the machine
turned on its side, and showing the influence which this position has on the
driving-strap.
In Figs. 1 to 7 and 10, A is the case for the under-thread spool B, which is free
to rotate within the case on a pin D, while it is kept in its place by a spring 11,
Fig. 1 having a pin riveted thereto, which projects through a hole into the case.
[Pitice Cd 1

page_text: and between the flanges of the spool. In Figs. 7, 10 and 11 this spring is shown
differently arranged and projecting with a bent portion over the spool. The said
spring may be drawn backward to release the spool by the finger-nail. The case
lies with its flange C in groove of the rotating disk E, the said groove being
formed by a rebate in the disk E and the annular segments 22 and 22' closing the
groove in front, and of which 22¹ is permanently fixed to the disk, while 22 is
pivoted at 23 and secured by a catch at. 24 (the segment itself forming the
springing part (so that 22 can be turned aside when the spool-case is to be
withdrawn or reinserted. The disk E is thus free to rotate in respect to the
case A, which is prevented from turning by the projection 20 bearing against the
fixed stop 21. R is the rotating hook forming a part of the disk E, and having on
its back the small hook 25.. In front of the hook R there is a gap 37, through
which the thread forming the loop passes from the outside of the hook R into the
space between the case A and the disc E. The outer portion 13 of the case is
bevelled on both sides so as to form an edge, serving to guide the part 35 of the
loop behind the case and the part 34 to the front thereof. For the length of the
portion 13, and for a certain distance from the same towards the top of the case,
the flange C. is cut away, and a recess 26 is formed in the said flange as shown
by Fig. 6. At 12 the case has a shoulder on which acts at the proper moment the
arm 14 for the purpose of interrupting the contact between the projection 20 and
the stop 21 (see Fig. 3) and of allowing the part 34 of the loop to pass between 20
and 21 without finding any resistance at this point. The said arm 14' forms part
of a lever 14, Figs. 10 and.12, operated by an eccentric 19 on the shaft G and
a-spring.
The rotating hook R, having caught the loop of the upper thread at the
beginning of the ascending inotion of the needle, as usual, carries it forward in
the direction of the arrow in, Fig. 1, and spreads it out, so that the part 34 will.
slide over the front side of the doubly bevelled portion 13 of the case, and the
part 35 over the rear side thereof and behind the case. After the hook has passed
the lowest point of the case, the take-up (not forming any part of this Invention)
comes into action and during the farther progress of the book, draws up the loop,
so as to keep it sufficiently tight around. the case; but in order to prevent it from
falling of the hook R, the small hook 25 is provided for, with which the loop now
engages as shown by Fig: 2. While the loop is being carried towards the bottom
of the case, its rear part 35 slips into the recess 26, and is there retained until the
hook 25 has arrived near the top of its course and allows the loop to slide off. By
means of this recess the thread of the loop is prevented from coming into contact
with the oily edge of the flange C, which requires constant lubrication. Fig. 2.
shows the position of the rotating hook just after the loop-part 34 has slipped over
the shoulder 12, and passed between this shoulder and the oscillating arm 14',
which until then is raised sufficiently to give passage to the thread. Subsequently
the lever 14 is depressed by the action of the eccentric 19, Fig. 12, and the arm 14'
caused to act against the shoulder 12, so as to move the spool-case into the
position Fig. 3, and to bring the projection 20 out of contact with the stop 21.
The loop-part 34 then slides away over the projection 20, while the loop, which
now encircles the under thread 31, is continually pulled upon by the take-up in
the measure as the hook 25 allows it to shorten. The said hook having finally
arrived near the top of the case, the loop slips off therefrom as well as out of the
recess 26, to be finally drawn up into the seam together with the under-thread 36.
Meanwhile the arm 14 has risen again, and the case has been returned by the
action of the friction between it and the rotating disk into the position of
Figs. 1 and 2, in which it bears against the stop 21.
Another improvement consists in means for adjusting the tension of the under
thread. In the arrangement shown by Figs. 1 and 7 the spool-case A is, for this
purpose, provided with a spring 1 fixed to the case by a screw 2. This spring is
curved in such a manner as that normally only its end which is held by the said
screw, is in contact with the case, while the remaining part is free. The free end

page_text: of the spring has a hole through which passes with some play the pivot 4 of a
disk 3. This disk bears against a flattened portion of the circumference of the
case.
In the middle of the spring there is a longitudinal slit and in the body of
the case a corresponding slit. The slit of the case has its sides bevelled (see Fig. 5)
so as to be wider on the inside than on the outside. In this slit slides a screw 7.
provided with a head that is square, but tapering so as to fit into the slit. The
screw passes through the slit of the spring 1, and on its end, outside of the spring,
there is a nut 6.
The
The thread of the spool B, is passed from the inside of the case A through the
portion 5 of the slit in the body of the case to the outside of the same.
thread is then slipped under the disk 3, and hereafter the end of the thread is
passed through one of the holes f, f¹, f" in a flange of the case, or through all
three holes. Subsequently the spool B is slipped on the pin D inside of the
case. The spool-case may then be put into the rotating disk.
1.
For altering the tension of the thread, which is clamped,between the disk 3 and the
Bat part of the periphery of the case, it is but necessary to-turn over the machine on
its hinges, as shown in Fig. 15, and to push the nut 6 and the screw 7 forward or
backward. By pushing it forward, i.e. towards the disk 3, the pressure of the free
end of the spring 1 on the disk 3 will be increased, and consequently there will be
a greater tension on the thread. By pushing the nut away from the disk, the
tension will be diminished. After the adjustment of the tension the machine is
turned back again on its hinges. This arrangement presents the advantage of
allowing the tension of the under-thread to be regulated without removing either.
the work or the spool-case from the machine. Besides, it is to be observed that
the adjusting operation can be carried out by hand without the use of a screw-
driver or other tool.
Another arrangement of an under-thread tension adjustable by hand and based
on the same principle as the foregoing, is shown by Fig. 5. The thread runs from
the spool-case through the hole as in Fig. 7; and after having passed the said
hole, it is covered with a flat spring 31. On this spring bears a pin 10, screwed
into the lever 9, pivoted at 8 to the work-plate 38; and to the said lever is screwed
with one end an arched spring 1', bearing with its other end upon the outer end of
the lever. Against the spring 1' acts a lever 61, pivoted to the plate 38, and the
arm whereof that is in contact with the spring 1', forms an eccentric bow. It is
evident that according as the lever 6' is turned one way or the other, the tension
of the spring 1' will be increased or diminished, and the pressure of the pin 10
against the flat spring 3' and of the latter against the spring 1' varied in
corresponding manner. In order to prevent the loop of the upper thread, which
has to pass between the pin 10 and the flat spring 3', from being detained at this
point, the arm 14¹ of the oscillating piece or lever 14, hereinbefore described, is
made use of in conjunction with an inclined projection 39 attached to the lever 9.
The lever 14 having such notion imparted to it as that it will be in its upper
position when the loop has to pass between the pin 10 and the spring 31, the
arm 141 in acting against the projection 39, will raise the lever 9' with the pin 10
at the proper moment, and thus cause the pin to allow the loop to pass without any
detention.
In the first-described arrangement the tension in no manner hinders the loop
of the upper thread from sliding around the spool case.
For the purpose of allowing the machine to be turned over on its hinges
without requiring the driving strap L, Figs. 13 to 15, to be thrown off the pulley
29, the strap is passed from the fly-wheel 27 over a guiding-sheave 28 to the
driving-pulley 29 of the machine and thence over another guiding-sheave,
laced by the side of 28, back to the fly-wheel. The said guiding-sheaves
arn freely on a pin screwed into the standard 31, fixed to the table M; and they
re placed with the upper part of their periphery in a line with the centre. of the
inges 40 of the machine. Above the guiding-sheave conducting the part of the
trap which passes from the pulley 29 to the fly-wheel 27, there is a pall 32

page_text: "
pivoted to the top of the standard 31. This pall bears gently on the strap without
hindering its motion in the proper direction; but in case the fly-wheel should be
turned the wrong way, the teeth of the pall 32 catch into the strap and hinder it
from driving the machine. This kind of pall is in itself not new; but it is made
use of in combination with the guiding-sheaves for preventing the strap from
becoming slack to such an extent as to be apt to fall off the pulleys, when the
machine is turned over.. For this purpose the pall is provided with an arm 38 of
such length as that it will take up a sufficient amount of slack of the strap to keep
the latter in the grooves of the pulleys. The arm 38, however, is not intended
to completely stretch the strap, so that when the machine is turned over, the fly-
wheel of the same may be rotated for allowing the machine to be cleaned and
adjusted.
The described arrangement of strap-guiding pulley and of means for taking up
the slack of the strap, are of special importance in respect to the under-thread
tension shown by Figs. 1 and 7, as the spool-case is accessible only after the
machine has been turned over, and as without the said arrangement it would be
necessary for every adjustment to throw off the strap and to replace it.
.
For making a good seam it is necessary to commence sewing close to the edge of
the cloth, and for this purpose the feed-bar must return to the needle after every
stitch, whether the same be long or short. In order to attain this object a piece 44
is attached to the carrier 42 of the feed-bar 43, Fig. 12, by two screws 51, passing
through slits in 44, and which are drawn tight to such an extent only as that,
with some exertion, the piece 44 may be shifted forward and backward on the
carrier 42. The said piece and the carrier are operated by an eccentric 45 on the
end of the shaft Q acting against the arm 46 of.44, while a spring 47 draws this
arm against the eccentric. The said eccentric may be provided with a roller, and
the arm 46 with a lining, to be exchanged when worn out. Under these conditions
the feed-bar will have a motion equal to the whole stroke of the eccentric, and
will therefore cause the cloth to be advanced for the longest stitch. For shortening
the stitches there is a stitch-regulating screw 49, working in the 'part 48 of the
feed-bar carrier 42. This screw has a circular groove 52, engaging, with a slit in
the arm 50 of the piece 44. By turning the said screw one way or the other, the
piece 44 will be shifted forward or backward, and the stitch will become shorter or
longer, because in the measure as the arm 46 is moved away from the eccentric 45,
the part of the revolution of the latter during which a contact between it and the
arm 46 takes place, will be less. If the piece.44 is pushed so far forward that the
flange 46 does not touch the.eccentric at all, no stitches whatever will be made.
But, whichsoever be the length of the stitches, the feed bar will always, at the end
of a stitch, be in its original position-close-to-the-needle:-The-screw-49-may-be-
regulated by hand without interruption of the work, as in turning the screw the
finigers involuntarily follow the oscillations of the machine.
The outer edge of the flange of the spool-case-and the inner surface of the groove
of the rotating disk in contact there with, require to be constantly lubricated. But,
in order prevent the thread from becoming greasy while passing around the spool-
case, a very regular and sparing supply of oil to the rubbing parts must be kept up.
For this purpose I employ a tube or other receptacle with a wick in it, projecting
therefrom, and adapted to be brought in contact with the rotating disk, in which
there is a small hole 18 leading to the groove of the disk. The said wick is kept
impregnated with oil. When the hole in the disk passes in front of the wick, it
strips off a small quantity of the oil and leads it to the groove. A lubricator of
this kind is shown by Fig. 10 and partly by Fig. 12. The wick 58 is contained in
a tube 16, provided on the outside with a screw-thread by which it is screwed into
a sleeve 15 fixed to the oscillating piece 14 and having an inside thread. In the
sleeve there is a slit 17, while the part of the tube 16 registering with the slit, is
provided with holes, so that the oil brought into the slit will pass through the
holes into the wick. The screw-thread on the tube allows the wick to be pressed
more or less against the disk. The sleeve 15 may, however, be fixed to some other

page_text: the tube 10 may be held and made adjustable in other
suitable manner.
The arrangement for winding thread on the spool A is shown in Fig. 9. The
outer face of the pulley 29 is made in the form of a disk 53, having a flat recess
corresponding to the shape of the spool, and another disk, 59, having a like recess,
is provided for, together with a screw 55 adapted to be passed through holes
in the disk 55 and in the spool, and to be screwed into the end of the shaft Q.
Moreover, a wire 50 bent into the form shown in the Drawing, and one part of
which is suitable for carrying the spool 57 with the supply of thread, is fastened
by a clamping screw or otherwise to the frame of the machine. In the part
of the wire 50 not carrying the spool 57, there are some holes through which
the thread is passed for imparting to it the requisite tension while being
wound on the spool A. The hole through which the thread is passed last
should be in a lino with the slit between the disks 53 and 59. This slit is
preferably made somewhat narrower than the distance between the flanges of the
spool. The spool having been placed between the disks. 53 and 59, and the parts
secured together, by the screw 55, thread may be wound on the spool while sewing
is proceeded with. During the winding operation the inner surfaces of the
recesses in the spool lies, prevent the flanges of the spool from bulging
outward.
Having now particularly described and ascertained the nature of this Invention
and in what manner the same is to be performed, as communicated to inc by my
correspondent, I declare that what I clain is:
1. In sewing-machines with stationary under-thread spool-case and a rotating
hook operating to draw the loop of the upper thread around the case, the
employment of a spool-case A having in the top part of its flange C à recess 26
adapted to receive and to retain the rear part of the loop during the passage of
the loop around the case, substantially as and for the purpose described.
2. The combination with the spool-case of a reciprocating arm acting against
an offset or a projection of the case, and operating to push the case in the direction
contrary to the sense of rotation of the hook when the loop is passing the part.
of the case bearing against a stationary piece, substantially as described.
3. In a two-thread sewing-machine the combination with the spool-case of an
under thread tension consisting in a spring adapted to cause a pressure on the.
under-thread, and of a movable piece bearing upon the spring and which may he
adjusted by hand without removing the spool-case from the machine, for the
purpose of augmenting or lessening the pressure with which the spring acts on the
thread, substantially as specified.
4. In a sewing-machine hinged to a table at its rear side, the combination with
the driving-pulley, the pulley on the main shaft of the machine and a driving-
strap, of two guiding-sheaves placed with the upper part.of their periphery about
in a line with the hinges of the machine, for the purpose of keeping the strap in
the grooves of the pulleys. when the machine is turned on its side.
5. The combination with the said pulleys, driving-strap and guiding-sheaves, of
a pall or catch adapted to prevent the strap from running backward, the said pall
having an arm, which, when the machine is turned on its side, bears against one
part of the strap in order to take up the slack in the same.
6. The combination with the feed-bar carrier, of a piece connected thereto
through which the feed-eccentric acts on the carrier and the feed-bar, the said
piece being adjustable in respect to the carrier by a regulating screw, so that after
each feed-motion the feed-bar will return to the same point whether the stitch be
long or short.
7. In combination with the disk of the rotating hook and a spool-case carried
by its flange in a groove of the disk, a lubricating device consisting in an
adjustable holder containing a wick adapted to be impregnated with oil and to be
brought in contact with the outer surface of the rotating disk in which there is a
hole leading to the groove,

page_text: 8. The device for winding thread on the under-thread spool, consisting in two
concave disks between which the spool is screwed against the end of the main]
shaft of the machine, the said disks leaving a slit between their edges for the
passage of the thread, substantially as hereinbefore described. .