IMPROVEMENTS IN ☐ SEWING MACHINES
Year: 1877

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields, in the
County of Middlesex, Gentleman, for the Invention of "IMPROVEMENTS IN
☐ SEWING MACHINES." A communication from abroad by James E. A. Gibbs, of
Steel's Tavern, Virginia, United States of America.
aled the 21st December 1877, and dated the 6th November 187'
f
COMPLETE SPECIFICATION filed by the said John Henry Johnson at the
Office of the Commissioners of Patents on the 6th November 1877.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,.
Gentleman. "IMPROVEMENTS IN SEWING MACHINES." A communication from
abroad by James E. A. Gibbs, of Steel's Tavern, Virginia, United States of
America.
The said Invention relating to sewing machines consists of improvements which
may be classed under the following heads, videlicet :-
:-
I. The under or bobbin thread tension and the holder and carrier for the bobbin
case.
II. The construction, arrangement, and combination of the bobbin case and the
hook.
III. The feed mechanism.
IV. The tension for the upper or needle thread and the combination therewith of
a pull-off adapted to deliver a length of thread which varies with the length of
stitch.
The first part of the said Invention, which relates to the under or bobbin thread
tension, and the holder and carrier for the bobbin case, has for its object obtaining
a tension which can be adjusted and regulated while the machine is in motion. To
this end the bobbin thread is passed between the bobbin case and an external
yielding independent presser, which bears upon or against the bobbin case.
presser may act either directly upon the thread itself or upon an intermediate disc
or discs, and it is adapted to be adjusted at any time so that the tension may be
regulated at will without necessitating the stoppage of the machine,
This

page_text: the accompanying Drawings.
Figure 2 is a plan of the under side of a sewing machine embodying the improve-
ments.
Figure 3 is a longitudinal central section of the tension-producing devices and the
hook.
Figure 9 is a perspective view of the bobbin case, of the form which it is preferred
to employ.
Figure 10 is an end view of the same.
Figure 11 is a transverse vertical central section.corresponding to Figure 10; and
Figure 12 is a perspective view of the case at the side opposite to that shewn in
Figure 10.
The particular device by which the tension is produced is a yielding presser A,
which in this instance acts also as the bobbin case holder. The part A consists
of a disc with a cup or recess on its outer face to receive the correspondingly shaped
face of the bobbin case B, which disc is carried by a shouldered stem or rod a
extending into and supported by a tubular bearing C, in the outer internally screw
threaded end of which is a nut b, between which and the shoulder on the stem a is
confined a spiral spring c. The presser with the holder is thus enabled to yield the
degree of pressure which it exerts on the bobbin case, being determined by com-
pressing the spring c more or less by means of the nut b. In the nut is an axial
hole of sufficient size to permit the play in and through it of the outer end of the
stem`a.
This presser is designed to bear with a yielding pressure against the bobbin
case, which on the other side is supported by any suitable means, in this instance
by a recessed disc d, which is fixed to an arm e projecting from the bearing C, as.
indicated in Figures 3 and 9.
In order to obtain the desired tension on the bobbin thread the thread may be
conducted from the bobbin once, twice, or more times across that face of the bobbin
case which is next to the presser, or the thread may be led entirely round the
bobbin case diametrically, and through suitable thread eyes in the periphery so as
to pass across and between both faces of the bobbin case and discs of the bobbin
holder, in which case the intermediate disc herein-after referred to will not be
needed.
The manner in which it is preferred to carry out the Invention is indicated in
Figures 10, 11, and 12. The bobbin case B is provided with a receptacle for the
bobbin B¹, as shown. On that face of the case which comes next to the presser are
formed four thread eyes f, two at top and two at bottom. The thread passes first
out through the top of the bobbin case, thence through one of the upper eyes f,
thence across the face of the case through the two lower eyes, and again across the
face, thence through the other upper eye. The thread is thus extended twice across
the face of the case. If the presser be formed to fit against this face of the bobbin
case it will be seen that it will bear upon the thread extended across the face,.
thus producing tension, and the degree of pressure it exerts upon that thread will
determine the degree of tension. This pressure being easily regulated by the nut,
and both bobbin case and presser having no rotary movement (although the bobbin
contained by the case is of course free to revolve) it follows that a bobbin thread
tension is obtained which answers all required conditions. In this case it is preferred
that the presser shall not be in direct contact with the bobbin thread, and there is
therefore interposed between the bobbin case and presser a disc g, which fits in a
recess in the bobbin case and over the thread stretched across its face, and is provided
with a central stem h, which not only secures the disc in position, but also serves as
the axis on which the bobbin B¹ may move.
The bobbin case is readily inserted in and withdrawn from its holder. When
inserted in place a depression i in its periphery fits against the arm e, thereby
securing the bobbin case in position, and preventing it from turning.

page_text: The recessed disc d and yielding presser A. constitute the bobbin case holder and
carrier, and are both attached to the bearing C.
In order to give the bobbin case holder and carrier the.capacity of moving to and
from the hook and to any position desired for adjusting the bobbin or bobbin
thread, or for other purposes, the bearing C is fixed to an arm C¹ pivotted to the
frame of the machine in substantially the same manner and by the same means as
is the self-adjusting and holding bobbin holder described in the Specification of
Letters Patent granted to me dated January 13th, 1876, No. 139.
The shoulder of the cam ¹ on the arm secures the bobbin holder and carrier. in
position for sewing when the arm is turned on its pivot, so as to move the parts
away from the hook, and the cam rides over the corresponding incline on the
bearing C², which receives the axis of the arm, and the spring compresses the spring
and gives the bobbin holder and carrier a movement bodily away from the hook.
In other words the devices here act precisely as described in the Specification of
the said former Letters Patent, except that now the parts are constructed to carry
with them the bobbin and bobbin case. This is advantageous, among other reasons,
because by swinging the bobbin holder and carrier round to a sufficient distance,
and by providing at a suitable point in the cloth plate a slide or removable portion
and removing this part the holder and carrier may be brought above the cloth plate
in such position that the bobbin case or bobbin thread may be adjusted readily and
easily.
The second part of the said Invention, which relates to the construction, arrange-
ment, and combination of the bobbin case and the hook has for its object using a
simple hook without disc or periphery, with a view of obtaining simplicity of con-
struction and lightness of running. In order to use such a hook however so as to
carry the loop over the bobbin case, it is necessary that the outer edge of the bobbin
case should be in a line with the path of the hook, and consequently on the same
side of the needle as the hook. On the other hand, in order to avoid the use of
disc or periphery on the hook, it is necessary that the bobbin thread should escape
from the bobbin case out of the path of the book, and on the opposite side of the
needle from that on which the hook operates. Hence it is necessary that a part of
the bobbin case should be on one side of the needle, in order to be in the path of
the hook, and that another portion of the bobbin case should be on the other side
of the needle to be out of the path of the hook. A bobbin case is therefore provided
having a needle passage formed in its periphery intermediate between its sides, and
with the bobbin case there is combined a needle which moves in a path intermediate
between the faces or sides of the case. There is also employed an oscillating hook
which describes somewhat more than a complete revolution alternately in opposite
directions.
The oscillating hook is used in preference to one rotating continuously in one
direction, because a regular movement can be imparted from a plain eccentric,
which is impracticable with the rotary hook, and because it will shed the loop
better, backing out of it with less liability of becoming entangled when there are
loose loops.
Figures 2, 3, 4, 10, 11, 12, and 14, represent these portions of the improvements.
Figure 4 is a section taken along the line 1-2, Figure 2.
Figure 14 is a view of the hook detached, looking towards the point of the
same.
The bobbin case B has already been referred to.
ད་;
It will be seen by reference to Figures 11 and 12 that it has a needle passage or
hole in its periphery intermediate between its sides, and that the needle is
arranged to play up and down in a similar path, so as to enter the passage. The
outer edge of the bobbin case is indicated at . The hook passes to the left of the
needle in Figure 11. The bobbin thread leaves the bobbin case on the right of the
needle beyond the thread guard l. The needle passes down closely along the side of
this guard, which is arranged, as shewn, to serve the double purpose of protecting

page_text: the under thread from interference with the needle, and of throwing out the loop
from the needle.
The hook D is a simple hook without disc carried by a radial arm on a shaft E,
supported in a suitable bearing, as shewn in Figures 2 and 4. The shaft E has on
its inner end a pinion E¹, which engages with a toothed sector F on a rock shaft F³,
extending the length of the machine and having a rocking movement imparted to it
by a crank arm F on its rear end which is connected with the pitman F1 of an
eccentric G, Figures 1, 2, and 5. The sector and pinion are so proportioned that
each movement of the former will cause the latter to make somewhat more than
one revolution. The hook therefore describes somewhat more than one revolution each
time the needle rises or descends, its revolution being alternately in opposite directions.
It takes the loop from the needle, carries it sufficiently far around the bobbin case to
insure that it will be drawn therefrom and its slack taken up by the take-up, and then
reversing its movement backs out of the loop and returns to position to take a fresh loop.
In order to enable the hook to act in this manner, it must be constructed to
The
turn or twist the loop before the latter passes over the bobbin case.
Drawings show such a construction (see Figures 2 and 14). The book consists of a
loop-taking point m and a guard u, with an intermediate inclined or slanting passage
between the two. The loop-taking point slants on the inside from its outer end back
or away from the needle, and the guard slants on the outside from its outer end
towards the needle. When the loop is taken by the loop-taking point it will gradually
be turned as the hook revolves, the inclined edges of the guard and point giving the
loop a twist as it passes over the bobbin case, thus enabling the hook to back
out of or shed the loop at the proper time.
The third part of the said Invention relates chiefly to novel means for regulating
the throw of the feed which in this instance is the ordinary four-motion feed.
This part of the Invention is illustrated more particularly in Figures 2, 4, 5, 6, 7,
and 8; Figures 2 and 4 have already been referred to.
Figure 5 is a section taken along the line 3-4, Figure 2.
Figure 6 is a longitudinal vertical section of the rear part of the machine, the
plane of section passing through the axis of revolution of the driving stud or
shaft on which are mounted several eccentrics for imparting movement to the various
parts of the machine.
Figure 7 is a vertical longitudinal section through the axis of oscillation of the
front part of the feed frame.
Figure 8 is a like section of the rear part of the said frame.
The feed bar carrying a suitable serrated feed surface is shown at o. It is pivotted
at o¹, between arms p projecting from and above the longitudinal rocking bar 1,
bung in fixed bearings, and obtaining a rocking movement from an eccentric H
by a pitman rod H¹, the latter being jointed at its lower end to a radial arm s¹,
projecting from a rock shaft s which is supported in bearings formed in arms 82 pro-
jecting from and below the bar r. At the forward end of the shaft s is another radial
arm which projects under the feed bar, and upholds the latter through the
intervention of the upright rod t, having a ball and socket in connection with
both bar and arm. A spring t¹ is provided which tends to push the feed bar down
and back.
Under the arrangement described, the feed, owing to the action of the rocking
feed frame and the spring, has imparted to it the usual up-and-down and to-and-
fro movement. The extent of the to-and-fro movement, which gives the length
of feed, is determined by the extent the rocking frame is oscillated by the
pitman H¹.
In order to regulate the throw of the pitman there is provided for it, inter-
mediate between its eccentric and its point of connection with the arms s¹, a
pivot v mounted on a slide v² adjustable in a slot v formed in and extending
longitudinally of the pitman, which pivot constitutes the axis of oscillation of
the pitman. The nearer this pivot is brought to the eccentric the greater will

page_text: be the throw of the lower end of the pitman, and consequently the more move-
ment will the rocking frame have. Therefore, by adjusting this pivot up or down,
the length of feed can be regulated at pleasure.
The movement of the pivot may be effected in any convenient manner. In this
instance it is provided for by connecting the pivot slide v² to a handle w, moveable
up and down in guides in the frame, with which handle may be combined, if desired,
a spring pressure pad w¹, for the purpose of holding it in any position to which it.
may be adjusted.
According to the fourth part of the Invention, which relates to the needle thread
tension and pull-off, a compound tension is provided, formed in two parts, of which
the one that first receives the thread exerts less tension than the other, and a pull-
off is combined therewith, which acts on the thread intermediate between the
two parts. The effect of this arrangement is that the pull-off naturally drawing the
thread through that part of the tension offering the least resistance takes the thread
from the spool. The resistance to the delivery to the needle of the thread thus taken
by the pull-off from the one part of the tension is of course confined to the other.
part of the tension. When this supply of thread is taken, then the thread becoming
taut is acted on by both parts of the tension which now offers the needed resistance
to enable the take-up to operate properly to complete the stitch...
It is preferred to provide a pull-off which is adjustable to regulate the amount of
thread delivered for the stitch, and it is also preferred to combine this. pull-off with
the feed mechanism in such a manner that the adjustment of the feed shall cause a
corresponding adjustment of the pull-off for the purpose of varying the delivery of
thread to correspend with variations in the length of stitch::
}
This portion of the improvements is illustrated in Figures 1, 5, and 6. Figure 1
is a perspective view of a machine embodying the improvements; Figures 5 and 6
have already been referred to.
The compound tenson is mounted on a bracket or shelf I on the rear part of the
goose neck of the machine.
:
I would remark at the outset that each part of the tension may be distinct and
independent of the other, and may be of any suitable construction. For the sake of
simplicity and convenience and economy of construction it is preferred however
to make them in one piece, and it is this form of tension which I have shewn in the
Drawing.
The tension consists of a single movable elongated plate w² placed on a like
stationary plate w³, which rests on the shelf. The plates are held in place by pins
x, y, which project from the shelf, and surrounding one pin x is a spiral spring x¹,
which is pressed down on the upper plate by a nut ² which screws on to the screw
threaded upper end of the guide pin x. In the plate, midway between the two pins,
are formed coinciding apertures 2, which register with a like apérturé extending
vertically through the shelf I. Up through the passage thus formed works the pull-
off rod I, which is jointed at its lower end by a pin-and-slot connection to a
horizontal radial arm I², extending from the rocking bar of the feed frame.
The rocking movement of the bar gives an up-and-down movement to the
pull-off rod.
The thread from the spool passes between the plates w², w³, entering the tension
at the end nearest pin y, leaving the tension at the opposite end, and in its passage
through the tension extending across the passage up through which the pull-off rod
:works.
:
..:
It is evident that the pressure of the plates is least at the point farthest removed
from the spring x1, and consequently that the portion of the tension to the right of
the pull-off, Figure 1, will not take so firm a hold on the thread as will the portion
to the left of the pull-off. Consequently when the pull-off rises it will when it meets
the thread stretched across the passage push up the thread, and the yield will come
from the side of the spool, which will deliver up as. much thread as is required by
the rise of the pull-off. When the pull-off. descends there will thus, be slack thread

page_text: between the two parts of the tension, which slack being the amount required for
the stitch will be drawn through the tension and delivered to the needle. After
however the slack has been exhausted and the thread stretched taut in the tension
the weaker portion of the tension supplements the action of the stronger. portion,
and the united pressure of both presents sufficient resistance to the passage of the
thread to enable the take-up, to perform its functions' properly.
The pull-off, as will be seen by examining the Drawing, rises and acts on the
thread, while the feed surface is moving down and back preparatively to taking, a
fresh hold on the goods.
It is obvious that the extent to which the pull-off rises above the normal level of
the stretched thread will determine the amount of thread delivered for the stitch.
It is therefore desirable to make the pull-off adjustable, so that any desired length
of thread may be delivered. The adjustment manifestly may be effected in various
ways. It is preferred however to connect it with the feed frame as above specified,
and to make the throw of that feed frame adjustable in the manner already stated,
so that the act of adjusting the feed will cause a like adjustment of the pull-off,
thus causing the amount of thread pulled off always to correspond to the length
of stitch.
Having now described and particularly ascertained the nature of the said Inven-
tion, and the manner in which the same is or may be used or carried into effect,
I would observe in conclusion that what I consider to be novel and original; and
therefore claim as the Invention is,―
First. The method of obtaining tension on the under or bobbin thread, which
consists in passing the same between the bobbin containing case and an external
independent yielding presser which bears upon or against the bobbin case, whether
the presser acts directly upon the thread itself or upon an intermediate disc or discs,
substantially as herein-before described.
Second. The combination, substantially a as set forth, of the bobbin containing
case and the tension producing presser, adjustable while the machine is in operation
for the purpose of regulating the tension.
Third. The freely revolving bobbin and the bobbin containing case, in combina-
tion with an external independent bobbin case holder, which exerts a yielding
and adjustable pressure upon the bobbin case, both to produce tension on the
bobbin thread, and to permit the free passage of the needle thread over or around
the bobbin case, substantially as herein-before described.
Fourth. The recessed bobbin case and tension washer or disc fitting the said recess
in combination with the external yielding presser, substantially as and for the pur-
poses herein-before described.
Fifth. The combination with the tension producing presser of the bobbin containing
case formed with threading eyes or their equivalent for holding in position across
the face or side of the case the thread to be subjected to the action of the said
tension producing presser.
Sixth. The combination, substantially as set forth, of the following elements,
vizt., the bobbin case holder, the bobbin containing case, the thread guard on said
case, the needle and the hook arranged to work on the one side of the said guard,
and the guide or eye arranged for the passage of the under-thread to the goods on
the other side of the said guard, the combination being and acting substantially as
herein-before described.
Seventh. A self-holding and self-adjusting bobbin case holder and carrier
pivotted to the body of the machine, and adapted to carry the bobbin and
bobbin case towards and away from the hook and needle and to any position
desired, in order to adjust the bobbin or bobbin thread, substantially as herein-
before described.
Eighth. The two part tension and intermediate pull-off in combination with
the feed operating mechanism connected with the pull-off, so that the adjust-
ment of the feed shall cause a corresponding adjustment of the pull-off for

page_text: the purpose of varying the delivery of thread to correspond with variations in
the length of stitch.
In witness whereof, I, the said John Henry Johnson, have to this my Com-
plete Specification set my hand and seal, the Sixth day of November, One
thousand eight hundred and seventy-seven.
J. HENRY JOHNSON. (L.S.)