IMPROVEMENTS IN SEWING MACHINES AND IN NEEDLES THEREFOR
Year: 1882

page_text: LETTERS PATENT to William Robert Lake, of the Firm of Haseltine, Lake,
& Co., Patent Agents, Southampton Buildings, London, for an Invention of
"IMPROVEMENTS IN SEWING MACHINES AND IN NEEDLES THEREFOR."
A communication from abroad by Messieurs E. Thimonnier, fils, and Vernay,
of Doria France
PROVISIONAL SPECIFICATION left by the said William Robert Lake at the
Office of the Commissioners of Patents on the 11th January 1882..
WILLIAM ROBERT LAKE of the Firm of Haseltine Lake & Co., Patent Agents,
Southampton Buildings, London. "IMPROVEMENTS IN SEWING MACHINES AND IN
NEEDLES THEREFOR." [A communication from abroad by Messieurs E. Thimonnier,
fils, and Vernay, of Paris, France.]
According to the present Invention I construct a sewing machine which effects
with one single thread a kind of lock stitch, a result which, as is well known has
heretofore been obtained only by using two threads; I am enabled therefore to
dispense with the use of a shuttle and to obviate the inconvenience resulting from
the use of a second thread. My improved machine produces a stitch which
resembles the hand-made stitch and which does not become unsewn, even when the
thread breaks.
In carrying the said Invention into practice I provide a hollow spool or reel
holder which contains the spool and carries a tension device which regulates the
supply of the thread. It also has a diametrical slot or groove in which the needle
works. The needle slides in the said slot and is connected to a jointed needle-bar
hereinafter described. A rotating hook surrounds the spool-holder and is designed
to cause the thread to pass above the needle so as to lock the stitch. An oscillating
book is arranged under the cloth-plate of the machine as hereinafter described and,
a curved thread tightener with a hook is also pivoted under the said cloth-plate.
I also provide a needle which has an eye near the point and a small hook at a
certain distance above the eye. In one form of needle the eye is replaced by a
double hook; either of these two needles may be used with the same results.

page_text: The spool holder consists of a circular box with rounded edges, formed of two
parts joined by means of two spring bolts which may be released by means of a
small tool that can be introduced through openings which are provided; the spool
which is inside the box may turn freely around its axis and furnishes the thread
as the machine requires it. The thread comes out of the box at a certain point,
passes under the tension device formed by a metallic spring, and thence goes
through an opening and a small conduit, whence it reaches the needle.
The front part of the spool holder forming the cover, has in its centre a vertical
slot or groove in which slides a block forming a head to the needle; the latter is
provided with a notch which adapts itself upon a small spring hook fixed to the
said sliding block. This block has also a small aperture into which fits a pro-
jection of the needle-bar. The said sliding block has also a lateral notch into
which fits a small spring catch placed in a groove in the front part of the spool
holder, and which prevents the motion of the needle when it becomes disconnected
from the needle-bar.
This spool holder is carried by the circular hook which surrounds it completely
and isolates it on all sides in order to allow the passage of the thread loop which is
to form the knot; moreover the connection of the sliding block with the needle
bar prevents it being carried around by the circular motion of the hook and when
the latter abandons it, so as to make a passage for the thread, it is maintained
motionless by a special oscillating piece with three branches jointed to the front of
the machine. The first branch of this piece is set in motion by the needle-bar
when it rises to disconnect itself from the needle. The second branch maintains
the spool holder in position by penetrating into a hole made upon its front face.
The third branch is acted upon by a retracting spring.
!
The circular hook is formed by a disc having a slit or opening where there is a
projecting nose which is to catch hold of the thread from the needle; this disc,
formed of three rings superposed, is placed in a circular depression made on the
front plate of the fore part of the machine, and is kept in position by a second disc
also slit at its lower part, and fixed to that plate by means of screws. Rotary
motion is transmitted to this hook in the following manner that is to say. A lever
in the curved support of the front part of the machine sets in motion, by means of
a connecting-rod, and another rod, a shaft with a crank which has at its extremity
a disc upon the rear part of which is placed a disc composed of two segments
forming between them a certain angle and placed in two planes which intersect
each other. This disc thus arranged is joined to the other disc by means of two arms
serving as joints. The shaft, when turning, causes the last named disc which is
fixed to its extremity, to move which latter communicates its rotary motion to the
segmental disc, the two portions of which situate in two different planes, pass
successively under a roller movable around a fixed axis and communicate alternately
with the rear part of the other disc. The segments have each one or several
projections which successively enter into corresponding holes made in the rear
surface of the circular hook. Thus there exists always at least one of the projections
in contact with this hook whose continuous motion is ensured, whilst the thread
can pass freely in the empty space behind the spool-holder one of the two pro-
jections being always, for that purpose separated from the hook which it was
causing to move the previous moment.
The last named disc is moreover terminated by an edge the two sides of which
constitute a double excentric, one of which effects and regulates the dividing of the
needle-bar and the other the motion of a lever hereinafter described.
The needle-bar of the machine as herein before stated is jointed and its flat
extremity terminates with a small projection designed to fit into a corresponding
notch in the sliding block; a flat spring tends to maintain this connection during
the time the jointed is not raised by the mechanism. This raising is produced by
a pin in one piece with a jointed lever and whose lower part is set in motion, at
the proper moment by a projection on the edge of the disc, which causes it to
oscillate, and compels it to raise the bar. Moreover the extremity going beyond

page_text: the joint of the lever and striking against the fixed plate of the machine, prevents
the other extremity of that lever from remaining in contact with the disc.
In order to ensure the passage around the spool holder of the loop carried by the
nose of the hook I arrange below the spool holder a shifting lever which enters the
loop seized by the hook and which is put in motion by means of the disc; this
rotating disc has on the opposite side of the projection a projecting edge whose
form is such as to cause at the proper time the displacement of the lever. This
articulated lever has three branches; one is acted upon by the projection of the
disc; the second takes the thread of the loop behind the spool-holder and brings it
into a free space which is arranged at its rear part; the third branch is subjected
to the action of a spring which tends to constantly bring back to its original
position the shifting lever.
The oscillating hook is pivotted under the cloth plate of the machine, and
receives a compound motion; it oscillates from right to left to take and leave the
loop which the needle presents to it, at the same time as it retires in a direction
parallel to itself, at the proper time to escape from the needle which has entered
its notch.
The oscillating motion is communicated to this hook by a shaft which carries at
its other extremity a crank whose pin fits in the groove of a disc fixed upon the
main shaft of the machine. The continuous rotary motion being communicated to
the shaft by a treadle or any other means; the disc in rotating, compels the pin to
assume an oscillatory motion determined by the form of the groove; in these
conditions the shaft communicates to the hook corresponding oscillations which
compel it to take up or leave the loop brought by the needle. The motion which
allows the hook to escape from the needle which enters its notch is produced as
follows. It carries a small contact roller provided with a regulator, and which,
during the oscillations of the hook, either strikes or does not strike against an
inclined plane the position of which can also be regulated and which then compels
the hook to swing around its horizontal axis, one of the projections of which
projects into the hook to ease the axis from its shearing strain in the communication
of the oscillatory motion.
The constant contact of the hook against the inclined plane is ensured by means
of a flat spring which at the same time secures the roller and parts connected
therewith.
The thread-tightener designed to give to the thread a constant tension is
arranged below the cloth-plate and has at one of its extremities a hook to seize the
thread; the other extremity of this device is joined to a shaft by means of a spiral
spring, designed to stretch the thread, when the pivotted hook draws back. Upon
the said shaft is fixed a crank having a roller which rests on a part of the disc this
part of the disc is cut in a convenient fashion determined by the different positions
which the thread tightener has to assume.
The presser-foot receives its motion from excentrics fixed on the main shaft. The
regulating of the stitch is operated by any of the means usually employed for that
purpose.
Oscillating levers communicate, through their upper extremity, to the needle bar
and the rod the motion they receive at their lower extremity and which is trans-
mitted to them by means of the cam fixed on the main shaft and having two cam
grooves wherein rollers at the lower end of these levers engage.
I may give to the oscillating hook a slight rotatory motion upon itself in order
to transform the stitch of one kind into one which differs from it only by the
intercrossing of the thread resulting from this tension given by the hook; I may
also place the point of passage of the needle on the very edge of the cloth plate of
the machine. In these conditions the stitch being no longer kept by the sides of
the opening provided in that plate for the passage of the needle-glides on the edge
of the material and forms a whip stitch which cannot become unsewn.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Robert Lake in the Great Seal Patent Office on the 11th July
1882.
"
WILLIAM ROBERT LAKE of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings London. IMPROVEMENTS IN SEWING-MACHINES AND IN
NEEDLES THEREFOR." A communication from abroad by Messieurs E. Thimonnier,
fils, and Vernay, of Paris, France.
According to the present Invention I construct a sewing machine which effects
with a single thread, a kind of lock-stitch, a result which, as is well known, has
heretofore been obtained only by using two threads; I am enabled therefore, to
dispense with the use of a shuttle, and to obviate the inconveniences resulting
from the use of a second thread. My improved machine produces a stitch which
resembles the hand-made stitch and which does not become unsewn, even when
the thread breaks.
Figures 1, 2 and 3, represent the kind of stitches made by the improved machine;
this stitch is the lock back-stitch represented in Figure 1; moreover by means of
a slight rotatory motion of the hook the machine produces the same stitch locked
or knotted as represented in Figure 2. A simple modification of the plate of the
machine allows the ordinary whip stitch to be made as represented in Figure 3.
In carrying the said Invention into practice I provide a hollow spool or reel
holder A which contains the spool a and carries a tension-device which regulates
the supply of the thread and also has a vertical slot or groove in which the
needle works. The needle B slides in the said slot or groove and is connected
to a jointed needle-bar hereinafter described. A rotating hook C surrounds the
spool holder A. and is designed to cause the thread to pass above the needle so
as to form the knot of the stitch. An oscillating hook D is arranged under the
cloth plate of the machine as hereinafter described, and a curved thread tightener E
with a hook is also pivotted under the said cloth plate.
I also provide a needle which is represented in Figure 4 and has an eye near the
point and a small hook at a certain distance above the eye. In one form of needle
represented in Figure 5 the eye is replaced by a double hook; either of these two
needles may be used with the same results..
I will now describe the various positions which the parts of the machine for
operating the thread successively assume during the formation of the stitch
referring to Figures 6, 7, 8, 9, 10, 11, 12, and 13 of the Drawing, which represent
these positions.
In the position represented in Figure 6. the thread, as it comes from the reel or
spool, passes through the tension device and the eye 6 of the needle B, goes through
the material at the place where it has been perforated just previously then descends
through the hole f bored in the plate F' of the machine passes round the hook D
reaches the thread tightener E where it is retained by the hook e and going up
again through the hole f¹, meets the preceding stitch made in the stuff.
In the second position all the parts are in a similar position except the needle B
which has descended passing through the loop formed around the hook D which
has a vertical recess d within which the needle descends; when it has reached the
end of its course, its notch b¹ is opposite the ascending part of the thread of the
loop retained for the time by the hook D and the thread-tightener E.
In the third position the needle and other parts of the mechanism have not been
moved but the hook D has moved back and a little to one side so as to disengage
itself from the needle which has penetrated into its notch; it thus leaves to the

page_text: thread tightener the loop which it retaines; a spiral spring fitted in the interior of
the head of the thread-tightener maintains a certain tension on the thread thus
left, and compels it to penetrate into the notch b' of the needle.
In the fourth position none of the parts have moved except the hook D which has
come forward again and into the new loop which the needle presents to it.
In the fifth position the needle has gone up carrying with it in its hook b¹ the
part of the thread forming the loop which the circular hook C carries around the.
reel or spool-holder A so that one of the sides of this loop remains in front and the
other passes at the back of this spool holder which is so arranged as to allow this
passage of the thread; this result is facilitated either by means of a small shifting
lever which takes one of the two sides of the loop behind the spool, or by any other:
means such as a helical blade for instance arranged on the spool holder. Whilst the
hook C rises in its rotation the thread tightener E acted upon by its mechanism
releases the thread it has stretched.
In the sixth position the beak c has gone beyond the vertical line and the loop
it carried along has passed between the spool-holder and the needle-bar which has
separated at this moment to make a passage for it and which at once reassumes
its connection with the needle; the beak c then releases its loop which escapes
Meanwhile the thread
freely by reason of the inverted position it has assumed.
tightener E which has also gone beyond its culminating point has let go the loop
which it held and then going back has seized, with its book e, the new loop caught
by the hook D which it opens by making use for that purpose of the thread of the
preceding loop released by the beak c of the circular hook C.
In the seventh position the needle B and the hook D have not moved, the
circular hook C has continued its motion towards the lower part at the same time
that the thread tightener E, going back rapidly has carried along with it the new
loop thus tightening the stitch formed.
In the eighth position the thread tightener has continued to tighten the stitch,
which, yielding to the tension thus produced, passes under the material and the.
presser-foot has forced the material forward towards the left hand the length of a
stitch and thus assisted in tightening the knot while placing the material in
position to receive a new stitch.
The formation of the stitch is effected as follows, that is to say; - The needle B
descending perforates the fabric and penetrates the loop held by the hook D, one of
the sides of which loop is held by the hook of the thread-tightener; this hook D
then moves back and a little to one side to disengage itself from the needle which.
has entered its notch, and thus going back, it abandons to the thread-tightener alone
the loop which they were both holding; then it advances again to seize the new
loop brought down by the needle.
The needle then ascends and when it has returned to its upper position the.
circular hook C seizes the thread of the needle and causes the loop which it forms
to pass around the spool-holder and the needle, the thread tightener E yielding up.
the thread in proportion to this movement until the hook C reaches the vertical;
at this moment the hook e of the thread-tightener having itself gone beyond the
vertical releases the thread of the first loop which the hook D had abandoned to it
and comes in its backward motion to seize by its lateral hook e the second loop
laid on the hook D; at this moment the hook C having in its turn gone beyond
the vertical releases the loop it retained the thread of which is drawn under the
plate of the machine by the thread tightener E, which, going backwards, tightens
the stitch and compels it to descend below the fabric at the same time that the
forward motion of the stuff completes the tightening of the knot and places the
fabric at the required place for it to receive another stitch.
It will be seen that in this machine the thread is never left to itself, the thread
tightener E having for its object to maintain in it a certain tension in all the
positions it successively assumes; which prevents it from getting entangled and
ensures the formation of the stitch.
The operations of these parts are effected by means of the improved mechanism
>

page_text: hereinafter described and represented in the accompanying Drawing. The spool
holder A represented in Figures 14, 15, 17, and 18, consists of a circular box with
rounded edges formed of two parts joined by means of two spring bolts R R¹
which may be released by means of a small tool that can be introduced through
the openings R and R¹; the spool a which is inside the box may turn freely around
its axis and furnishes the thread as the machine requires it. The thread comes
out of the box at 8, Figure 14, passes under the tension device S formed by a
metallic spring and thence goes through the opening 8¹ and the small conduit 811
whence it reaches the needle B.
The front part of the spool-holder A. forming the cover has in its centre a vertical
slot or groove in which slides the block F forming a head to the needle; the latter
is provided with a notch which fits upon a small spring hook or spurf Figures 14, 15,
fixed to the said sliding block F. This block has also a small aperture into which
fits the projection m³ of the needle-bar M. The said sliding block F has also a
lateral notch into which fits a small spring catch t placed in a groove T in the
front part of the spool-holder and which prevents the motion of the needle when it
becomes disconnected from the needle-bar M.
This spool holder is carried by the circular hook C which surrounds it completely
and isolates it on all sides in order to allow the passage of the thread loop which
is to form the knot; moreover the connection of the sliding block F with the needle-
bar prevents its being carried around by the circular motion of the book C, and
when the latter abandons it, so as to make a passage for the thread, it is maintained
motionless by an oscillating piece G with three branches jointed to the front of
the machine. The first branch g of this piece, Figures 14 18 and 19. is operated
by the needle bar M when it rises to disconnect itself from the needle. The second
branch maintains the spool-holder in position by penetrating into a hole made
upon its front face; the third branch g¹¹ is acted upon by a retracting spring.
The circular hook shewn in detail in Figures 14 15 and 18 is formed by a
dise C having a slit or opening where there is a projecting beak c to seize the
thread from the needle; this disc formed of three rings superposed, is placed in a
circular depression made in the front of the machine, and is kept in position by a
second disc Q also slit at its lower part, and fixed to the said plate by means of
screws. Rotary motion is transmitted to the hook C in the following manner,
that is to say a lever y in the curved support of the front part of the sewing
machine actuates by means of a connecting-rod K and a rod K¹ Figures 15 16 17
and 19 a crank shaft I which has at its extremity a disc L upon the rear face of
which is arranged a device O composed of two segments p p' forming between
them a certain angle and placed in two planes which intersect each other; this
device thus arranged is joined to the disc L by means of two arms o o¹ serving
as joints. The shaft I when turning, causes the disc L which is fixed to its
extremity, to move, which latter communicates its rotary motion to the segmental
disc O the two portions of which, situated in two different planes, pass successively
under a roller P movable around a fixed axis and coming in contact alternately
with the rear face of the disc L. The segments p p have each one or more.
projections q q¹ which successively engage with corresponding apertures made in
the rear surface of the circular hook C; so that there is always at least one of the
projections qq' in contact with this hook whose continuous motion is ensured
whilst the thread can pass freely in the empty space J behind the spool-holder, one
of the two projections q q¹ being always, for that purpose, separated from the
hook C which it was causing to move the previous moment.
The disc L is moreover terminated by an edge the two sides of which constitute
a double eccentric, one of which eccentrics effects and regulates the dividing
of the needle-bar, and the other the motion of the lever hereinafter described.
The needle bar of the machine as shewn in Figures 14 15 17 and 19 is jointed
and its flat extremity M terminates in a small projection m¹ designed to fit in a
corresponding notch in the sliding block F a flat spring m" tends to maintain this
connection while the jointed piece M is not raised by the mechanism. This raising

page_text: is produced by a pin m in one piece with a lever H jointed at h¹ whose lower part
is actuated, at the proper moment, by a projection on the edge of the disc L
which causes it to oscillate and compels it to raise the piece M. Moreover the
extremity h going beyond the joint h¹ of the lever H and striking against the
fixed plate of the machine prevents the other extremity of that lever from
remaining in contact with the disc L
In order to ensure the passage around the spool holder of the loop carried by
the beak c of the hook CI arrange below the spool holder a shifting lever N
Figures 14 15 16 17 and 19 which enters the loop seized by the hook C and
which is put in motion by means or the disc L for this purpose the rotating disc L
has on the opposite side of the projection la projecting edge whose form is such
as to cause at the proper time 'the displacement of the lever N. This articulated
lever has three branches; the one n is actuated by the projection of the disc L;
the second n¹ takes the thread of the loop behind the spool-holder, and brings it
into this free space J.which is arranged at its rear part; the third branch n¹ is
subjected to the action of a retracting spring which tends constantly to bring back
the shifting lever to its original position.
The oscillating hook D represented in detail in Figures 20 21 and 23 is pivotted
under the cloth-plate of the machine, and receives a compound motion; it oscillates
from right to left to take and leave the loop which the needle presents to it, at the
same time as it retires in a direction parallel to itself at the proper time to
escape from the needle which has entered its notch.
The oscillating motion is communicated to the hook D by the shaft U
Figures 21, 24, 25, and 26 which carries at its other extremity a crank u whose
pin u¹ fits in the groove v of a disc V fixed upon the main shaft 1 of the machine,
continuous rotary motion being communicated to the main shaft by a treadle or
other suitable means; the disc V in rotating compels the pin u¹ to assume an
oscillatory motion determined by the form of the groove v under these conditions
the shaft U communicates to the hook D corresponding oscillations which compel
it to take up or leave the loop brought by the needle B. The motion which
allows the hook D to escape from the needle which enters its notch is produced as
follows, that is to say. It carries a small contact roller W provided with a
regulator, which roller during the oscillations of the hook either comes in contact
with or passes an inclined plane W₁ the position of which can be adjusted and
which then compels the hook D to swing around its horizontal axis d' one of the
projections of which projects into the hook to ease the axis from its shearing
strain in the communication of the oscillatory motion.
The constant contact of the hook D against the inclined plane W¹ is ensured by
means of a flat spring S which at the same time secures the roller W and parts
connected therewith.
The thread tightener E designed to give to the thread a constant tension is
represented in Figures 20 22 24 25 and 26; it has at one of its extremities a
hook e to seize the thread; the other extremity e¹ of this device is connected to
the shaft E by means of a spiral spring designed to stretch the thread, when the
hook D draws back. Upon the shaft e¹ is fixed a crank e having a roller e³
which rests on the part of the disc, V, this part of the disc is cut in a suitable
manner determined by the different positions which the thread tightener E has to
assume.
The presser-foot represented in Figures 25 and 20 receives its motion from the
excentrics 2, 3, fixed on the main shaft 1. The regulation of the stitch may be
effected by any of the means usually employed for that purpose.
The levers Y Z oscillate around their axis X and communicate motion, through
their upper extremities to the needle bar M and the rod K¹ which motion they
receive at their lower extremity and which is transmitted to them by means of the
cam 4 fixed on the main shaft 1 and having two cam-grooves y z, wherein engage
rollers at the lower ends of these levers.

page_text: The other parts of less importance are only indicated on the Drawing, which
allows the operation thereof to be readily understood.
I may give to the oscillating hook D a slight rotatory motion in order to
transform the stitch represented in Figure 1 into that indicated in Figure 2 which
differs from it only by the intercrossing of the thread resulting from this tension
given by the hook D. I may also place the point of passage of the needle on the
very edge of the cloth plate of the machine; under these conditions the stitch
being no longer kept by the sides of the opening provided in that plate for the
passage of the needle, glides on the edge of the material and forms a whip stitch
which cannot become unsewn and which is represented in Figure 3.
Having thus fully described the said Invention as communicated to me by my
foreign correspondents and the manner of performing the same I wish it understood
that claim.
First-The improved sewing-machine hereinbefore described and shewn in the
accompanying Drawing, for producing by means of a single thread the descriptions
of lock-stitch represented in Figures 1, 2, and 3 respectively, which machine
comprises the spool holder, the needle and its needle-bar, the circular hook, the
oscillating hook and the thread tightener all combined and operating substantially
as and for the purposes set forth.
Second-The needle having an eye or a double hook at its lower part, and a
small hook situated at a suitable distance from the said eye, substantially as, and for
the purposes set forth.
Third: The spool holder fixed in the lower portion of the front part of the
machine and supported by means of the circular hook which carries round the said
loop to allow free passage for the said loop, the said spool holder being prevented from
rotating by means of the needle-bar and a jointed spring lever operating whilst the
needle-bar is disconnected, all substantially as set forth.
Fourth-The spool-holder carrying internally the spool which supplies the thread,
and, upon its front face the sliding block forming a head to the needle, the tension-
spring and a spring catch for maintaining the needle motionless while the needle-
bar is disconnected, substantially as set forth.
Fifth-The circular hook capable of turning freely in a groove in the front plate
of the machine and provided with a beak which carries round the loop, the said
circular hook receiving rotary motion, from an oscillating disc or similar device the
projections of which are successively detached from the said hook so as to make
way for the thread, all substantially as set forth.
Sixth-The jointed needle-bar which is adapted to be separated at the required
moment from the head of the needle, under the action of a lever actuated by a cam
operated by the mechanism, all substantially as set forth.
Seventh-The oscillating hook placed below the cloth-plate of the machine to
seize the thread and having a notch to permit the passage of the needle to
penetrate the loop which it holds back, the said hook having a double backward
and forward motion to seize and release the loop of thread, and a lateral motion to
disengage itself from the needle which has penetrated into its notch, all substantially
as set forth.
Eighth-The thread tightener for maintaining the thread constantly tightened
during the passage of the loop above the spool-holder and the needle, and to tighten
the knot formed, and receiving its forward and backward motion from a curved
sliding block dovetailed into a rotating plate, and having upon its axis a spiral spring
which ensures a certain elasticity in its movements, all substantially as set forth.
Ninth The shifting lever for ensuring the passage behind the spool-holder of
the loop seized by the beak of the circular hook, the said lever being set in motion
by means of a cau actuated by the mechanism, substantially as set forth.
Tenth--The rotating disc L forming a double excentric for regulating the shifting
lever N and the separation of the needle-bar by means of levers arranged for that
purpose, the said disc serving also to carry along the bent disc O whose projections

page_text: successively penetrate into and abandon the hook C to leave free passage to the
thread, all substantially as and for the purposes set forth.
Eleventh The oscillating hook D actuated by means of a grooved cam and
having a hook adapted to allow of a small lateral displacement under the action
of an adjustable inclined plane, substantially as, and for the purpose set forth.
Twelfth The thread tightener actuated by means of a grooved cam operated
by the mechanism, substantially as set forth.
Thirteenth-The means above described to permit the transformation of the lock-
stitch represented in Figure 1 into a similar stitch but crossed as represented in
Figure 2, and the transformation of that stitch into a lock-stitch that will not
become unsewn, substantially as set forth.
In witness whereof I the said William Robert Lake have hereunto set my
hand and seal this Eleventh day of July, in the year of our Lord One
thousand eight hundred and eighty two.
W. ROBT. LAKE. (L.S.)