IMPROVEMENTS IN SEWING MACHINES
Year: 1877

page_text: LETTERS PATENT to John Keats, of Wood Green, in the County of Middlesex,
Mechanical Engineer, for the Invention of "IMPROVEMENTS IN SEWING
MACHINES." Partly a communication from abroad by George Greenwood, of
Leeds, but now residing at New York, United States of America.
Sealed the 17th July 1877, and dated the 20th January 1877.
"
PROVISIONAL SPECIFICATION left by the said John Keats at the Office
of the Commissioners of Patents on the 20th January 1877.
JOHN KEATS, of Wood Green, in the County of Middlesex, Mechanical Engineer.
IMPROVEMENTS IN SEWING MACHINES." Partly a communication from abroad by
George Greenwood, of Leeds, but now residing at New York, United States of
America.
The chief object of this Invention is to increase the speed of sewing machines in
which a reciprocating shuttle is employed to produce a lock stitch, and to reduce
the friction on the needle thread in that class of lock-stitch machines in which a
rotary shuttle or its equivalent is employed.
Hitherto in the working of lock-stitch machines, much time has been lost in
carrying back the shuttle to its starting position after it has passed through the
needle loop, and in those cases where a rotary shuttle is used, and no dwell was
needed to give time for the shuttle to pass through the loop, the needle had an
unnecessarily long stroke in order to consume the time requisite for the performance
by the other acting parts of the mechanism of their respective duties, thus causing
great friction on the thread. Now in order to avoid these inconveniences, we adopt
the following arrangement of parts, that is to say, we place our locking thread in an
egg-shaped thread case, and support it between fingers (three or more), which are
pivotted to a stationary frame, and are operated alternately by a rotating cam in
such manner as to free them from contact with the thread case for the purpose to be
presently explained.
Supposing the Invention to be applied to a machine for sewing leather, in which
a piercing hook is used for pulling up a wax thread from below the work supporter,
the fingers which carry the thread case are pendent from the head of the machine,
and they are arranged concentrically around a spindle which carries the cam for
rocking the fingers. On the lower end of this spindle we fit an instrument, which
may be termed the loop carrier, the object of which is to carry the loop which has
•

page_text: been brought up by the hook from below (and which has been opened by the
divider), around the thread case, and thereby to lay the locking thread within that
loop. In this thread case we provide a suitable tension for the thread, and we
avail ourselves of the containing capacity of the case to supply fluid wax thereto for
the purpose of keeping the thread thoroughly saturated.
When applying our Invention to sewing machines, in which a vertical needle is
used, we propose to place the thread case and its supporting and operating
mechanism below the table, providing for the same any suitable fixed bearings in
the framing; in this instance no divider for opening the needle-thread loop will be
required, as the loop carrier during its rotation will seize the loop, open it out, and
carry it round the thread case, thus locking the thread.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Keats in the Great Seal Patent Office on the 19th July
1877.
"f
JOHN KEATS, of Wood Green, in the County of Middlesex, Mechanical Engineer.
IMPROVEMENTS IN SEWING MACHINES." Partly a communication from abroad by
George Greenwood, of Leeds, but now of New York, United States of America.
The chief objects of this Invention are, firstly, to increase the speed of boot and
shoe sewing machines known as the Crispin machines, in which a reciprocating
shuttle is employed to produce a lock stitch; and, secondly, to reduce the friction on
the needle thread in that class of lock-stitch machines in which a rotary shuttle
or its equivalent is employed.
Hitherto in the working of reciprocating shuttle machines, much time has been
lost in carrying back the shuttle to its starting position after it has passed through
the loopof the hook or needle thread, and in those cases where a rotary shuttle is used,
and no dwell was needed to give time for the shuttle to pass through the loop, the needle
had an unnecessary long stroke in order to consume the time requisite for the per-
formance by the other acting parts of the mechanism of their respective duties, thus
causing great friction on the thread. Now in order to improve the working of the
Crispin machine, the following arrangements of parts is adopted, that is to say, the
locking thread is placed in an egg or pear-shaped thread case, and supported between
fingers (three or more) which are pivotted to a fixed bracket piece, and are operated
alternately by a rotating cam in such a manner as to free them from contact with
the thread case for the purpose to be presently explained.
Supposing the Invention to be applied to a machine for sewing leather, in which
a piercing hook is used for pulling up a wax thread from below the work supporter,
the fingers which carry the thread case are pendent from the head of the machine,
and they are arranged concentrically around a spindle which carries the cam for
rocking the fingers. On the lower end of this spindle an instrument is fitted,
termed the loop carrier, the object of which is to carry the loop, which has been
brought up by the hook from below (and which has been opened by the divider),
around the thread case, and thereby to lay the locking thread within that loop.
In Sheet I. of the accompanying Drawings, the Invention is shown applied to what
is known as the "Crispin " sewing machine, the details of which in its most im-
proved form are set forth in the Specification of a Patent granted to me in conjunc
tion with Arthur Greenwood and Alphonso Keats, and bearing date the Eighteenth
day of February One thousand eight hundred and seventy-four.
Fig. 1, Sheet I., shows in side elevation so much of a Crispin machine with my
improvements applied thereto as will serve to explain the nature of the present
Invention, and Fig. 2 is a front elevation of the same.
A, A, is the casting forming the head of the machine. Working in suitable
bearings in the casting is the driving shaft B, which carries the cams for working
the barbed hook C and the loop opener D, as heretofore. In place of the reciproca

page_text: ting shuttle, which is situate above the work, a thread case E is employed for
supplying the locking thread to the loops formed by the vertical reciprocating
hook C. This thread case admits of slight modifications, but the form which I
prefer to employ is that shewn in section, on an enlarged scale, at Fig. 3, Sheet II.
It consists of an egg or pear-shaped case divided horizontally into two parts, and
having a lip or projection at the division or contact edges, which lip enables the
supporting fingers F to, grip the case and hold it securely in position. Of these
fingers there are by preference four which are pivotted to a bracket piece F¹ made
fast to the under side of the casting A. The construction of this bracket piece and
the parts in connection therewith are best shewn at Figures 4, 5, 6, and 7, Sheet II.
Fig. 4 being a section through the centre of the bracket head, or in the line 1, 2, of
Fig. 6; Fig. 5 being an inverted plan view of the same; and Figures 6 and 7, top
views of the bracket piece, showing also the gearing for reciprocating the support-
ing fingers, and for giving rotary motion to the thread carrier.
The head of the bracket piece is cast with radial slots to receive the fingers F, and
to the ribs which form the lower ends of these slots the fingers are pivotted. The
bracket piece F¹ forms a bearing for a central short spindle F2, to which is keyed a
cam F³, into the groove of which (or the under face thereof) the upper ends of the
supporting fingers take. This cam is so shaped (see Figures 4 and 6) as to throw
out the fingers in succession clear of the thread case, and thus provide a free passage
between it and the fingers of the rotating thread carrier G. The stem of this
thread carrier fits into a socket made for it in the centre for the spindle F2, so that it
rotates with the cam F³, and follows up the action of that cam, taking the loop of
the hook or needle thread from the divider D, and laying it around the thread case
that it may receive the locking thread therefrom.
In order to time the rotation of the thread carrier to suit the operations of the
hook, motion is communicated to the spindle F2 in the following manner :-
On the driving shaft B is a spur wheel B¹, which gears into a spur wheel H¹ on a
horizontal shaft H, having its bearings in the head of the machine, and lying parallel
to the driving shaft B. On the front end of this shaft H is a bevil pinion H²,
which gears into a bevel pinion I, keyed to a sleeve which is mounted on a stud axle
on the bracket piece F¹.
The sleeve which carries this bevil pinion carries also 'a segment rack I' and a
spur pinion I2, and in the same planes with this rack and pinion I', I², are the pinion
K and segment rack K¹ respectively, these latter being keyed to the vertical
spindle F. When therefore rotary motion is given to the bevil pinion I, its seg-
ment rack being in gear with the pinion K, as shewn in Fig. 6, a quick rotary
motion will be given to the thread layer G, but on the segment rack K¹ coming
into gear with the pinion I2, as shewn in Fig. 7, a comparatively slow rotary motion
will be imparted to the thread carrier. Supposing now the hook C to descend
through the work and receive on its hook the thread from the looper, it will draw
up that loop to its full height, then dip slightly to slacken the thread, and at this
moment the divider D will be advanced by the action of its cam on the shaft B, as
is well understood, and caused to open and take up the loop. The thread carrier G.
which is formed with a hooked extremity, as shewn at Fig. 1, will then take the
loop from the divider and lay it around the case E. The fingers, as the thread
carrier advances, moving outwards to allow it to pass round, the thread is in-
serted in the thread case C, by preference in the form of a cop, and being led within
an eye, a guide inside the case, it is led out at the bottom of the case, and thence to
the work, where the end is held until the thread is secured in the work.
Any approved system of tension may be applied to the cop thread, but care must
be taken that no obstruction is offered to the free passage of the loop around the
thread case.
To facilitate the removal of the empty case, and the replacing it by a full one, I
propose to joint one of the fingers, as shewn at Figures 4ª, Sheet II., which will
allow of its lower end being bent backwards. The joint of this finger may be
stiffened by a spring slide, the edges of which will clip the grooved sides of the

page_text: finger. The normal position of this slide will be in line with the joint, but when
slidden upwards, the finger may be moved back to the dotted position, thus allowing
ample space for the removal and the replacement of the thread case.
The means employed for feeding the work forward and for pressing it or holding
it down against the drag of the ascending hook, will be by preference similar to
that described in the before-mentioned Specification, and will require no explanation
in this place.
In Sheet III. I have shewn an arrangement for giving a reciprocating motion to
the thread carrier. Fig. 1 being a side elevation, and Fig. 2 a front view of the
head of a Crispin machine with my Invention thus modified applied thereto.
In place of the gearing above described, the pinion on the spindle F2 is made to
gear into a segment rack L, which is connected by a link L' to a rock lever L² that
receives a reciprocating motion from a cam L³ on the driving shaft B. This cam,
which is similar to the cam used for imparting reciprocating motion to the shuttle
in the machine described in the before-mentioned Specification, will through the
segment rack L give the desired reciprocating revolving motions to the thread
carrier, timing those motions to suit the movements of the vertical hook or
needle. In this case the cam, which rocks the supporting fingers F, will operate in
reverse directions, and thus always open a passage between the supporting fingers
and the thread case in the direction in which the thread carrier is moving.
In Sheet IV. I have shewn the Invention as applied to an ordinary lock-stitch
sewing machine, the thread case and thread carrier being situate below the table of
the machine, instead of above, as in the former example. In this instance no
divider for opening the needle thread loop is required, as the loop carrier during its
rotation will seize the loop, open it out, and carry it round the thread case, thus
locking the thread.
Fig. 1 is a side elevation, partly in section, of a feed wheel lock-stitch sewing
machine with my Invention thus modified applied thereto; and Fig. 2 is a plan
view of the mechanism employed for giving a reciprocating motion to the thread
carrier. A is the driving shaft, communicating motion through bevil pinions to a
vertical shaft B, which carries at its lower end a cam C, shewn in plan view at
Fig. 2.
The groove of this cam receives a bowle carried by a rock lever D, which has
its fulcrum at D¹ below the bed of the machine. This rock lever D terminates in a
segment rack D2, which gears into a pinion E mounted loosely on an inclined stem
E made fast to a fixed bracket E2. The upper end of the stem E¹ terminates in a
cup-shaped socket, which is intended to receive the thread case F and hold it loosely
therein. On the boss of the pinion E the thread carrier G is mounted, the same
being so situated with respect to the vertical needle H, and timed with respect to
its movements, that it will seize the loop formed by the vertical needle, and lay it
around the thread case F in order to bring the locking thread within the loop. As the
thread case F is supported not by reciprocating fingers, but by a cup-shaped socket,
the case will have no annular projection similar to that shewn in Sheet I., II., and III.
of the Drawings. Some means will however be required to secure the upper and
lower parts of the case together. For this purpose a bayonet joint, or equivalent
contrivance not presenting any obstacle to the free passage of the loop of the needle
thread around or over the thread case, may be employed, and any approved arrange-
ment for giving tension to the cop thread in the case may be provided. The thread
will in this instance pass out of the top of the case, as shewn in the Drawing,
instead of at the bottom, as before explained.
It will be seen that in this arrangement, as in that last described, a reciprocating
motion is given to the thread carrier, but the device described with reference to
to Sheets I, and II. for driving the thread carrier may be employed if thought
desireable. I is the feeding wheel, and K a rotary presser for holding down the
work on the table L. As the means for operating the parts H, I, and K are well
known, and form no part of this Invention, any description thereof would be
necessary.
Having now set forth the nature of the Invention of "Improvements in Sewing

page_text: Machines," and explained the manner of carrying the same into effect, I wish it to be
understood that under the above in part recited Letters Patent I claim,—
First. The use of a stationary thread case for carrying the locking thread, such
case being supported by reciprocating fingers in such manner as to allow of the
hook or needle thread being laid over or around it.
Second. The combination with an egg or pear-shaped locking thread case of a loop
carrier, operating as and for the purpose above described.
In witness whereof, I, the said John Keats, have hereunto set my hand and
seal, the Second day of July, in the year of our Lord One thousand
eight hundred and seventy-seven.
JOHN KEATS. (L.S.)