ROVEMENT Invention of SEWING MACHINES
Year: 1876

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields, in the
" IMPROVEMENTS IN
County of Middlesex, Gentleman, for the Invention of
SEWING MACHINES." A communication from abroad by James E. A. Gibbs, of
Steele's Tavern, Augusta County, in the State of Virginia, United States of
America
Sealed the 30th June 1876, and dated the 13th January 1876.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at the
Office of the Commissioners of Patents on the 13th January 1876.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN SEWING MACHINES." A communication to me from
abroad by James E. A. Gibbs, of Steele's Tavern, Augusta County, in the State of
Virginia, United States of America.
This Invention relates, 1st, to that class of machines known as lock stitch
machines, and particularly to that descripton of such machines in which a rotary
hook is employed to interlock the upper and under threads, and this part of the
Invention relates principally to the structure and operation of the revolving hook.
It also relates to the bobbin holder or moveable device by which the bobbin that
carries the under thread is held against or in its proper relations to the hook:
The improved hook is designed to be rigidly mounted upon a revolving shaft, for
which purpose it is provided with a central stem which can be inserted and fixed in
the end of the shaft. It is a bobbin containing a hook, that is to say, one formed
ns is usual in revolving hook lock stitch sewing machines with a recess on one face
to receive the bobbin. It is characterized by a certain construction and formation
substantially as herein-after described, whereby the loop taken by it from the
needle is carried over the face and rear of the body of the hook.
The position to which the loop is carried by the revolving hook is one diame-
trically or nearly so across the body in front and rear of the latter, which position
or substantiaily which position the loop maintains until released by and upon
completion of the revolution of the hook.
The body of the hook consists of a segment one extremity of which forms the
hook proper, and between this and the heel or opposite end the body of the hook
is cut away or recessed down to or nearly down to the central stem so as to form a
flat edge or surface.

page_text: Upon the rear side of the hook is formed an inclined surface which leads to an
under-cut groove or notch forined in the body of the hook, and extending radially.
or thereabouts from the centre of the stem to the circumference or periphery of the
hook. In this groove the portion of the loop which is on the rear of the hook is
retained until it is released from the hook.
The improved bobbin holder is pivotted and capable of oscillating on said pivot
in a plane parallel or substantially so with the face of the bobbin, it also is capable
of moving bodily in a direction at right angles with its plane of oscillation. The
former movement is for the purpose of bringing it in front of the bobbin as the case
may be. The latter movement is for the purpose of causing it to press towards or
retire from the bobbin. The mechanism which renders the bobbin holders capable
of these two movements is so combined and arranged that when the pivotted
bobbin holder is brought in front of the bobbin it will thereby be caused to press
towards or against the bobbin and vice versa.
According to one mode of carrying out this part of the Invention the holder is
hung on a cylindrical pin or spindle supported and adapted to turn in a bearing
formed on or fixed to the cloth plate. This spindle is capable also of endwise move-
ment in the bearing, which movement is in part controlled by a coiled spring located
in an enlargement of the bearing surrounding the spindle, and held compressed
between the bottom of the chamber or enlargement and a flange on the inner end of
the spindle. On the outer end of the bearing is an incline, and on the contiguous
face of the bobbin holder is a lug, projection, or corresponding incline to work
against the incline first. mentioned. When the bobbin holder is in front of the
bobbin the inclines occupy such relation to one another as to permit the spring to
draw the bobbin holder to the proper position to hold the bobbin in place; when,
on the other hand the bobbin liolder is moved to uncover the bobbin by and during.
this movement.it will be caused to recede from the face of the bobbin by the action.
of the projection or incline secondly mentioned, which passes over the face of the
-first-mentioned_incline, and thus produces an outward endwise movement of the
spindle, compressing the spring, and carrying the bobbin holder outwardly from
the face of the bobbin.
The second part of this Invention has reference to controlling the needle thread
during that period of the operation of the machine when the needle is on its down
stroke, and before the needle eye reaches or enters the goods. On the upper end of
the needle bar above the head there are provided two eyes, which project to the
rear of the bar. Between these eyes is an upright bar-fixed to the head, which bar
has an offset on its rear, in which is formed a vertical slip, which divides this part
into two jaws, the entrance between the jaws of the hook being from below. In
the main part of the bar which constitutes one jaw is a light and very sensitive
spring strip, which bears against the inner face of the opposite jaw. The eyes are
60 placed that a thread stretched between them will be in the plane of the slit.
These two jaws and the spring constitute an intermediate tension or friction pad.
The thread passes from the spool to the pull-off, then to the tension, and from
the tension through the two eyes, and thence to the needle.
The length and height of the upper end of the spring in this friction pad is so
adjusted that at the extreme upward stroke of the needle bar and thread carrier,
the thread is carried just above and beyond the end of the spring, and is, thus
released and entirely free from the action of the spring at the moment that the
stitch is being completed, and does not interfere with the proper tightening up of
the stitch, but instantly re-enters under the spring, when the thread begins to
descend, thus producing a double intermittent action at each successive stitch.
Under this arrangement the friction device itself has no movement, but it is
entirely passive. The thread during the up stroke enters the friction pad, on the
down stroke it by its own movement frees itself from the friction pad, leaving it at
the proper time to enable the needle to throw out a free loop.
In shuttle or other lock stitch machines it is desirable and important for perfect
sewing that the two threads shall interlock as nearly as possible within the body

page_text: of the cloth, that is to say, the needle thread should be drawn down and the under
thread up into the goods, so that there shall be no appearance of loop on either
side of the fabric. In order to effect this in machines heretofore made and used
having an invariable tension, the under thread being drawn up by the action of
the upper thread upon it, and this action being necessarily continued in order to
draw the thread through the tension to form the next stitch after the under
thread is drawn into its proper place in the goods, reliance had to be placed on
the increased friction produced by the drawing up into the goods of the under
thread to arrest any further movement of it into or through the goods; but inas-
much as this friction varies with different fabrics, with the thickness of the thread
and other conditions, there is no certainty of uniformly perfect sewing.
The third part of this Invention has for its object the accomplishing of the
desired result without fail, and independently of the thickness of fabric or thread,
by the employment of a tension device acting on the under thread substantially
in the following manner-The tension device acts directly upon the upper thread,
and through the intermediary of the latter thread upon the under thread. In
carrying out this part of the Invention two thread clamping surfaces or dics are
employed, through which passes a central spindle, the whole being contained in a
case, which also encloses à spring for effecting the clamping action, as las pre-
viously been adopted. According to the present Invention however, the two clamps
or discs are arranged to act alternately, so as to positively clamp and hold the
thread, and to exercise the gentle pressure necessary to permit the requisite amount
of thread to be drawn at the proper time through the tension, by which means
the necessity for employing two distinct sets of devices is obviated.
_
The two clamps or discs are enabled to co-operate by the following means :-
The upper disc rests loosely on the lower one, the spindle passes loosely through
them, and above the upper disc it carries or is formed with an enlargement
chambered to receive a light spring, which is under slight compression, and bears
upon the upper disc. The enlargement or head, when the spindle is down, bears
forcibly upon the upper disc, pressing it so tightly upon the under disc that the
thread between the two discs is clamped rigidly. When however the spindle
rises the head is lifted; the upper disc is thus relieved from clamping pressure, and
is subjected at that time to the action of the spring alone, whose force is such as to
exercise only that slight pressure which is requisite to prevent too free delivery of
the thread. Between the head and upper disc is interposed a sound deadening
washer to prevent noise during the operation of the machine.
The spindle is intermittently operated by an adjustable tappet on the upper end
of the connecting rod, and working in the lower cylindrical open end of the case,
such connecting rod being actuated by an eccentric on the driving shaft. This
eccentric is so placed that the lifting of the tension to release the upper thread takes
place at about the time when the needle has completed its up stroke. It will thus
be seen that the tension clamps the thread firmly, and to all intents and purposes
rigidly, during the greater part of the needle stroke, releasing it momentarily or for
a brief period at a certain point during the ascent of the needle, at which time the
take up draws through the tension the supply of upper thread needed for the next
stitch. The movements of the tension are so timed with relation to those of the
stitch forming devices that during the ascent of the needle, and while the bobbin or
shuttle thread is drawn up by the loop of the upper thread, the tension is so great
that no upper thread can be delivered, and therefore the loop is necessarily carried
up, drawing with it the under thread up into the goods, at which point the tension
is suddenly released, preventing further drawing up of the two threads. By thus
timing the movements of the tension the two threads in the completed stitch meet
within the body of the goods, and their point of interlocking is perfectly concealed,
and the stitching on each side of the goods presents the same appearance.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Henry Johnston in the Great Seal Patent Office on the 6th July
1876.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN SEWING MACHINES." A communication to me
from abroad by James E. A. Gibbs, of Steel's Tavern, Augusta County, in the
State of Virginia, United States of America.
The said Invention relates, first, to that class of machines known as lock-stitch
machines, and particularly to that description of such machines in which a rotary
hook is employed to interlock the upper and under threads, and this part of the
Invention relates principally to the structure and operation of the revolving hook.
It also relates to the bobbin holder or movable device by which the bobbin which
carries the under thread is held against or in its proper relations to the hook.
The improved hook is designed to be rigidly mounted upon a revolving shaft, and
is a bobbin containing a hook, that is to say, one formed, as is usual in revolving
hook lock-stitch sewing machines, with a recess on one face to receive the bobbin.
It is characterized by a certain construction and formation substantially as herein-
after described, whereby the loop taken by it from the needle is carried over the
face and rear of the body of the hook.
The position to which the loop is carried by the revolving hook is one diame-
trically or nearly so across the body in front and rear of the latter, which position,
or substantially which position, the loop maintains until released by and upon
_completion of the revolution of the hook.
.
The improved bobbin holder is pivoted and capable of oscillating on the said
pivot in a plane parallel or substantially so with the face of the bobbin; it also is
capable of moving bodily in a direction at right angles with its plane of oscillation.
The former movement is for the purpose of bringing it in front of the bobbin or
causing it to uncover the bobbin, as the case may be. The latter movement is for
the purpose of causing it to press towards or retire from the bobbin.
mechanism which renders the bobbin holders capable of these two movements is so
combined and arranged that when the pivoted bobbin holder is brought in front of
the bobbin it will thereby be caused to press towards or against the bobbin, and
'vice versa."
The
This Invention relates, secondly, to controlling the needle thread during that
period of the operation of the machine when the needle is on its down stroke, and
before the needle eye reaches or enters the goods.
In the operation of interlacing of the stiches in sewing machines a considerable
amount of slack thread is required, varying in different machines according to the
looping dovices used from inch to 2 inches or more. During the ascent of
the needle this slack is taken up by the needle bar or other take-up device, and is
again released and allowed to become slack during the descent of the needle to
furnish the necessary slack to be manipulated by the looping apparatus, but this
Black is not needed until the eye of the needle is about to enter the goods, and
previous to that time this slack is not only necessary but injurious from its liability
to become entangled with the point of the needle, hence various devices have been
employed to control the slack during that time.
The devices heretofore used for the purpose may be divided into three classes,
videlicet, first, those which hold the thread rigidly by the arrest of motion of the
take-up, by which it does not hegin to descend until the proper time for slack. The
objection to this class is the cuinbrous nature of any mechanism having intermittent
notions and their holding the thread too rigid for proper action. Second. Those
using a slight intermediate tension teclinically known as a "friction pad" to control
this slack. These are found objectionable from the fact that although they control
the thread properly during the first part of the descent of the needle their con-
tinued action, however slight it may be, is injurious after the eye of the needle has

page_text: entered the goods when perfect slackness is required. Third. A class which is an
improvement upon the last, and consists in an automatic or mechanical movement
given to the friction spring or pad which holds the thread so as to seize and release
the threads at the proper times, but this class in turn is found to have the serious
defect that any mechanical device by which so slight a friction as is needed can be
made intermittent is too delicate for durability, and is very liable to disarrangement
from wear and use. This Invention belongs to the latter class in so far that a slight
friction spring is employed having an intermittent action, but this is so obtained as
to remove the aforesaid objections. Under this improved arrangement the friction
device itself has no movement, but it is entirely passive. The thread during the
up stroke enters the friction pad; on the down stroke it by its own movement frees
itself from the friction pad, leaving it at the proper time to enable the needle to
throw out a free loop as above stated.
In shuttle or other lock-stitch machines it is desirable and important for perfect
sewing that the two threads shall interlock as nearly as possible within the body of
the cloth, that is to say, the needle thread should be drawn down and the under
thread up into the goods, so that there shall be no appearance of loop on either side
of the fabric. In order to effect this in "machines heretofore made and used having
an invariable tension, the under thread being drawn up by the action of the upper
thread upon it, and this action being necessarily continued in order to draw the
thread through the tension to form the next stitch after the under thread is drawn
into its proper place in the goods reliance had to be placed on the increased friction
produced by the drawing up into the goods of the under thread to arrest any further
movement of it into or through the goods, but inasmuch as this friction varies with
different fabrics with the thickness of the thread and other conditions there is no
certainty of uniformly perfect sewing.
This Invention has for its object, thirdly, the accomplishing of the desired result
without fail, and independently of the thickness of fabric or thread by the employ-
ment of a tension device acting on the under thread substantially in the following
manner: The tension device acts directly upon the upper thread, and through the
intermediary of the latter thread upon the under thread.
The tension clamps the thread firmly and to all intents and purposes rigidly
during the greater part of the needle stroke, releasing it momentarily or for a brief
period at a certain point during the ascent of the needle, at which time the take-up
draws through the tension the supply of upper thread needed for the next stitch.
The movements of the tension are so timed with relation to those of the stitch
forming devices that during the ascent of the needle, and while the bobbin or
shuttle thread is drawn up by the loop of the upper thread the tension is so great
that no upper thread can be delivered, and therefore the loop is necessarily carried
up, drawing with it the under thread up into the goods, at which point the tension
is suddenly released, preventing further drawing up of the two threads. By thus
timing the movements of the tension the two threads in the completed stitch meet
within the body of the goods, and their point of interlocking is perfectly concealed,
and the stitching on each side of the goods presents the same appearance.
And in order that the said Invention may be fully understood I shall now proceed
more particularly to describe the same, and for that purpose shall refer to the several
Figures on the annexed Sheet of Drawings, the same letters of reference indicating
corresponding parts in all the Figures.
Figure 1 is a perspective view of the hook, looking at it from the front; Figure 2
is a like view of the same from the rear.
Figures 3 to 6 are diagrams indicating the positions assumed by the loop at
various points in the revolution of the hook.
The hook being designed for rigid attachment to a revolving shaft is for conve-
vience sake furnished with a central stem a, which can be inserted and fixed in the
end of the shaft. The outer face of the hook is recessed, as shewn at b, to contain
the bobbin. This recess may be of ordinary or suitable formation, well known to

page_text: .
those skilled in the art
The hook proper is shown at c, and the heel or opposite.
end at d. Between the two extremities c and d the body of the hook is cut away
down to or nearly down to the central stem a, as shewn at c. Upon the rear side
of the hook is formed an inclined surface, which leads to the under cut groove or
notch f, which is formed in the body of the hook, and extends radially or thereabouts
from the centre of the stem to the circumference or periphery of the hook. In this
groove the portion of the loop which is on the rear of the hook is retained until it
is released from the hook.
*
The position occupied by the loop at various points in the revolution of the hook
is indicated in Figures 3 to 6. The direction of movement is indicated by the
arrows. In Figure 3 the hook is just entering the loop; in Figure 4 it has moved
about a quarter revolution further. During this movement the loop has left the
hook proper
c, and the bottom of the loop has travelled along the face c, and
reached the centre of the hook, at which point, as seen in the Figure, the loop has
been carried over the face and rear of the hook, and extends diametrically across the
hook with its rear part in the undercut retaining, groove f. In the next Figure
(Figure 5) the hook 'has moved about a quarter revolution further, which had the
effect of bringing the loop to the position indicated; its rear part still retained and
held in the groove f, while the front part of the loop is about clearing the rounded
heel & of the hook. In the next position (Figure 6) the hook has nearly completed
its revolution, and is about releasing the loop, which by this time has been turned
so as to bring g in front and h in rear. A slight movement further of the hook will
have the effect of releasing the loop..
The improvements in bobbin holders are illustrated in Figures 7 and 8, the former
Figure representing a front view of 50 much of a sewing machine as is requisite to
show the position of the holder in relation to the other parts of the machine. A is
the cloth plate; B, the upright front plate which supports the feed and the revolving
hook shaft. To this plate is pivoted at i the bobbin holder c, which so far as
-concerns that part of it designed to fit against and hold the bobbin may be of the
usual or suitable construction. The holder c is hung on a horizontal pivot, which in
the example shewn in the Drawings is a cylindrical pin or spindle j supported and
adapted to turn in a bearing & formed on or fixed to the plate B. This spindle is
shown inore clearly in Figure 8, which is a vertical section of the spindle bearing.
The spindle is capable also of endwise movement in the bearing, which movement is
in part controlled by a coiled spring located in an enlargement m of the bearing
surrounding the spindle, and held compressed between the bottom of the chamber
or enlargement m and a flange or projection m₁ on the inner end of the spindle.
The spring thus arranged tends to hold the bobbin holder against the end of the
bearing. On the outer 'end of the bearing is an incline n, and on the contiguous
face of the bobbin holder is a lug projection or corresponding incline o to work
against the incline n.
When the bobbin holder is in front of the bobbin the inclines occupy such relation
to one another as to permit the spring to draw the bobbin holder to the proper
position to hold the bobbin in place. When, on the other hand, the bobbin holder
is inoved to uncover the bobbin by and during this movement, it will be caused to
recede from the face of the bobbin by the action of the projection or incline o, which
passes over the face of the incline n, and thus produces an outward endwise move-
ment of the spindle, compressing the spring, and carrying the bobbin holder out-
wardly from the face of the bobbin. In this manner the bobbin holder, whilst
arranged to swing upon a pivot, also is enabled to hold and release the bobbin, as in
ordinary machines.
Figure 9 is a side elevation of a machine embodying the improvements which
form the subject of the second part of this Invention; Figure 10 is a plan of the
said machine.
Figure 11 is a sectional view of the frictional pad on an enlarged scale.
The machine may be any sewing machine of ordinary or suitable construction,

page_text: The one shown in the Drawing is a rotary hook lock-stitch machine. It is not
necessary to describe it in detail, and I here note only the principal parts which
require to be named in order to explain the Invention. A is the cloth plate; B, the
head; C, the goose neck; D, the needle bar; E, the vibrating needle arm; F, the
pull off; and G, the tension proper. The needle thread passes from the spool to
the pull off, thence to the tension, thence to the needle bar and needle; its course
is plainly indicated in the Drawing. On the upper end of the needle bar above the
head there are provided two eyes a, a, which project to the rear of the bar; between
these eyes is an upright bar bfixed to the head, which bar has an offset on its rear
in which is formed a vertical slit c which divides this part into two jaws, tho
entrance between the jaws of the hook being from below; in the main part of the
bar which constitutes one jaw is a light and very sensitive spring strip d, indicated
by dotted lines in Figure 9, and also in full lines in Figure 11, which bears against
the inner face of the opposite jaw. The eyes a are so placed that a thread stretched
between them will be in the plane of the slit c. These two jaws and the spring
constitute the intermediate tension or friction pad herein-before referred to. The
thread passes from the tension G through the two eyes a, a, and thence to the
needle. The result of this arrangement is as follows: Premising that the eyes a, a,
are so placed with relation to the said friction that when the needle bar rises the
thread stretched across between the eyes enters the friction pad as the needle leaves
the cloth, and on the down stroke leaves the friction pad when the needle has
reached or just entered the cloth. On the up stroke of the needle the needle thread
is taut, and consequently that part which extends across between the eyes a, i,
when rising with the eyes will have no difficulty in entering and traversing the
slot c, encountering the merely nominal resistance of the spring d. By the time
the thread has reached the upper end of the slit the needle has completed its up
stroke and the supply of thread for the next stitch has been drawn. When the
needle commences its down stroke the thread between the eyes a, a, commences to
move through the friction pad and continues therein until the needle reaches or
enters the goods, at which time the eyes a have descended sufficiently far to cause
the thread to withdraw itself entirely from the pad. So long therefore as the
thread during the down stroke continues in the pad the thread in the neighbour-
hood of the needle is kept straight without appreciable stretching or tension, but
the moment the needle reaches the goods even this tension ceases and the thread is
remitted to the loose and slack condition requisite for the formation of a proper
loop. The length and height of the upper end of the spring in this friction pad is
so adjusted that at the extreme upward stroke of the needle bar and thread carrier
the thread is carried just above and beyond the end of the spring, and is thus
released and entirely free from the action of the spring at the moment that the
stitch is being completed, and does not interfere with the proper tightening up of
the stitch, but instantly re-enters under the spring when the thread begins to
descend, thus producing a double intermittent action at each successive stitch.
Figure 12 is a side elevation of the machine with the tension device which forms
the subject of the third part of this Invention in vertical central section; and
Figure 13 is a rear view of the machine. A is an enclosing case; B, a moveable
spindle; a, a protecting cap fixed to the head of the spindle;, the spring by
which the clamping action is effected; J, the lower of two thread clamping surfaces
or rings; and, the upper clamping surface. These parts are constructed and
arranged together substantially in the manner described in the Specification to
Letters Patent granted to James Willcox, dated the Fourth July, One thousand
eight hundred and seventy-one, No. 1744, with the exception that the two parts
and I act alternately so as to positively clamp and hold the thread, and to exercise
the gentle pressure necessary to permit the requisite amount of thread to be drawn
at the proper time through the tension, by which means the necessity for employing
two distinct sets of devices is obviated.
The parts and J are enabled to co operate by the following means:-The upper

page_text: 1
disc v rests loosely on the lower one J, the spindle B passes loosely through them
and above the upper disc it carries, or is formed with an enlargement b chambered
to receive a light spring c which is under slight compression, and bears upon the
upper disc. The enlargement or head b when the spindle is down bears forcibly
upon the disc pressing it so tightly upon the under disc J that the thread
between the two discs is clamped rigidly. When however the spindle rises the
head is lifted, the upper disc is thus relieved from clamping pressure and is
subjected at that time to the action of the spring c alone whose force is such as to
'exercise only that slight pressure which is requisite to prevent too free delivery of
the thread. Between the head band the upper dise is interposed a sound deadening
washer a to prevent noise during the operation of the machine.
:
The spindle is intermittently operated by an adjustable tappet I on the upper
end of the connecting rod C and working in the lower cylindrical open end of the
case A as described in the Specification of the said former Letters Patent.
The needle, pull off, take up, feed, and revolving hook, and other devices forming
part of the sewing machine are of ordinary or suitable construction and require no
description here.
The spindle through the intermediary of the connecting rod and tappet is
operated by an eccentric D on the driving shaft, indicated by dotted lines in
Figure 13. This eccentric is so placed that the lifting of the tension to release the
upper thread takes placo just about the time the needle has completed its up stroke.
The needle operating eccentric is lettered E, the connecting rod F, vibrating needle
arm lever G, and the needle bar H. Thus it will be seen that during the up stroke
tho clamping of the upper thread by the tension will cause the loop formed by the
said thread to be drawn up. As this loop has engaged the lower thread the latter
will be drawn up also, and inasmuch as the upper thread is clamped until about
the time when the up stroke of the needle terminates, the consequence will be that
the under thread will inevitably be drawn into the goods or fabric, and that the
-point of junction or interlocking of the two threads will be within the body of the
goods. The tension being released at this point the two threads remain in this
position without further disturbance, and thus the object sought to be attained is
accomplished.
Having now described and particularly ascertained the nature of the said
Invention 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 bo novel and original,
and therefore claim as the Invention secured to me by the herein-before in part
recited Letters Patent is,-
First. A bobbin containing hook rigidly mounted upon a revolving shaft, and
constructed substantially as herein-before described so as to carry the loop over the
face and rear of the body of the hook which encloses the bobbin.
Second. A bobbin containing hook rigidly mounted upon a revolving shaft, and
constructed substantially as herein set forth so that the loop taken from the needle
shall be carried by the hook, while in the act of revolution diametrically across the
body of the hook and held thereon thus diametrically until released by and upon
the completion of the revolution of the hook as herein-before described.
Third. The combination with the rotary hook and bobbin of a self-holding and
adjusting bobbin holder pivotted to the body of the machine, substantially as
herein-before described.
Fourth. A bobbin holder pivotted to the body of the machine and combined with
mechanism, substantially as herein set forth, whereby simultaneously with its
movement upon its pivot it is caused to move bodily towards or away from the face
of the bobbin, substantially as herein-before described.
Fifth. The combination for the purpose of controlling the slack of the needle
thread of a stationary tension or friction pad, and a thread carrier which moves in
unison with the needle and operates to carry the thread into and withdraw it from the
said tension at the times and in the manner substantially as herein-before described.

page_text: Sixth. The needle thread controller or friction pad tension having a double
intermittent action by which the thread is controlled during a part of the
descent of the needle, and is left perfectly free both during the latter part of the
descent of the needle, and at the termination of the extreme upward stroke,
substantially as and for the purposes herein-before described.
Seventh. The friction pad constructed substantially as herein-before described in
coinbination with the needle bar, and the two thread eyes thereon arranged to
move one on each side of the friction pad during the reciprocation of the needle bar
for the purposes herein set forth.
Eighth. In a lock-stitch sewing machine the combination with the mechanism
for delivering and interlocking the two threads of a tension arranged to act on the
under thread through the intermediary of the upper thread at the times and in the
manner herein-before described.
In witness whereof, I, the said John Henry Johnson, have to this my Specifi
cation set my hand and seal, the Thirtieth day of June, One thousand eight
hundred and seventy-six.
J. HENRY JOHNSON. (L.S.)