IMPROVEMENTS IN SEWING MACHINES
Year: 1873

page_text: LETTERS PATENT to Alfred Johnson, of the British, Foreign, and
Colonial Patent Office, Newhall Street, Birmingham, in the County
of Warwick, for the Invention of "IMPROVEMENTS IN SEWING
MACHINES."
Sealed the 10th March 1874, and dated the 11th September 1873.
PROVISIONAL SPECIFICATION left by the said Alfred Johnson at
the Office of the Commissioners of Patents, with his Petition, on
the 11th September 1873.
I, ALFRED JOHNSON, of the British, Foreign, and Colonial Patent
Office, Newhall Street, Birmingham, in the County of Warwick, do
hereby declare the nature of the said Invention for "IMPROVEMENTS
IN SEWING MACHINES," to be as follows :-
My Invention relates to improvements in that form of sewing
machine in which a single thread is used and a succession of chain
stitches is formed by means of a vibrating hook or looper, the point of
which enters the loop formed by the needle below the fabric which is
being sewn, and having opened it sufficiently retains it until the needle

page_text: re-enters it after having left the work and then re-penetrated it for the
purpose of making a fresh stitch in the new position to which the
work has been advanced by the feeding mechanism.
My improvements consist of a novel method of constructing,
arranging, and guiding the bar which carries the needle; of a novel
method of forming the hook by which the stitches are made, and of
driving the same; and of a novel method of constructing and supporting
the presser, by which the work is kept down upon the plate of the
machine. By these improvements such sewing machines are made
more simple, cheaper, and more certain in their operation than in chain
stitch sewing machines as heretofore made.
In my improved sewing machine I take a framework (preferably of
cast iron), which forms the bed of the machine, and may be screwed
to a table or stand of wood, or other suitable foundation. One end of
the framework (which I call the front end) has suitable projections
formed upon or attached to it to carry and hold by means of screws
the table, over which the work passes in the usual way. The other
end of the framework (which I call the back end) has formed upon it
or attached to it a suitable bearing, in which revolves a shaft or axle,
the other end of which passes through and revolves in a bearing formed
in the projection which carries the table. The end of the shaft which
passes through the bearing in the back end of the machine has fixed
upon it a toothed pinion, which is driven by a larger toothed wheel
turning upon a centre screwed into the upper part of the projection
on the framework adjoining it. Instead of toothed wheels pulleys
connected by an endless band or cord may be used, and the larger
wheel is driven by a handle connected to it, or by a crank and treadle
in the usual way. The wheels may be covered by an ornamental
casing screwed to the framework, which casing may also serve to
support the bearing upon which the larger wheel revolves.
Upon the shaft immediately inside the bearing in the back part of
the framework I form a crank (or excentric) of suitable radius (or
throw) for the purpose of driving the needle bar up and down. The
needle bar consists of a horizontal bar or arm of suitable size (preferably
of malleable cast iron), having formed at its front end a vertical bar a
or arm, the lower end of which carries a vertical straight needle of the
kind ordinarily used in sewing machines, and attached to the bar by.

page_text: means of a bolt or screw. The back end of the needle bar has formed
upon it a vertical bar or arm, the lower part of which is provided with
suitable vertical guiding holes or notches, which fit upon and slide up
and down upon one or more (but preferably two) vertical guide bars,
the lower ends of which are supported by the plate forming the bottom
of the framework of the machine, and the upper ends are supported by
projections formed upon or attached to the upper part of the projection,
already described, at the back end of the framework. The lower part
of the vertical arm at the back of the needle bar is provided with a
horizontal slot arranged at a height between the upper and lower
guides which work upon the needle bar, and of sufficient length and
width to fit over the pin of the crank already described. By this
method of construction and arrangement the needle bar and needle
are caused to rise and fall vertically at each revolution of the shaft.
I prefer to make the slot described open at one end for the greater
convenience of removing and replacing the needle bar, and I arrange
the vertical guide bars and guides a sufficient distance laterally (in front
view) from the centre line of the needle bar and shaft, so that the
latter may escape them in its vertical motion up and down. A spring
may be used if desired to aid the upward movement of the needle bar.
The front end of the shaft has formed upon it or attached to it a disc
carrying a crank pin, which enters a slot or recess formed in the back
of a vibrating hook, the lower end of which is pivotted upon a screw
fixed to the front projection upon the framework. The hook is thus
made to vibrate backward and forward by the revolution of the shaft,
and I make the slot or recess in the hook curved, so that the movement
of the latter in forming the stitch may be exactly at the required
moment.
The point of the hook is formed in the way and of the shape well
understood and practised for forming the stitches in chain stitch sewing.
machines, but I attach to it in front a supplementary hook of elastic
wire, the point of which is pressed closely against the point of the
principal hook, so that both enter the loop of the thread together; but
after touching at its point the supplementary hook separates from the
other hook (in plan) so as to open out the loop of thread upon them
and secure the certain entry between them of the needle point into
such loop when making the next stitch. When the hooks are again
retracted after the needle has entered the loop the elasticity of the

page_text: supplementary hook allows it to separate sufficiently from the principal
one to allow the needle and thread to (pass between their points. The
supplementary hook is attached to the principal one at a point near the
centre, upon which the latter turns. The foot which presses the work
upon the plate of the machine may be made in the usual way, but I
prefer to attach it to a vertical bar, the upper end of which is fixed to
one end of a flat horizontal spring, the other end of which is screwed
or otherwise fixed to the projection already described at the back of the
framework. I sometimes make the vertical bar pass or slide through
a suitable guide attached to or formed upon the lower end of the front
vertical arm of the needle bar.
The apparatus for feeding forward the work may be of any of the
kinds ordinarily used in sewing machines. I prefer however to use a
feeding bar, the upper edge of one end of which (or of a plate attached
to it) carries projecting angular teeth which pass through a suitable
opening in the work plate of the machine. The other end of the
feeding bar has a horizontal slotted or forked end, which forked end
turns upon and slides upon a screw fixed to the projection which carries
the work plate, between which screw and the inner end of the slot a
spring is arranged, which constantly forces the feeding bar laterally
towards the needle.
The shaft between the disc which carries the crank pin, already
described, and the front bearing has two projections or excentrics formed
upon it, one adjoining the bearing and the other adjoining the back of
the disc. One of these projections is so arranged that it lifts the teeth a
upon the needle bar through the opening in the work plate at the
moment when the feed is to take place, and the other is so arranged
that at the same moment it presses against a vertical projection upon the
feed bar, which is thus forced laterally, and so feeds the fabric forward.
As the shaft continues its revolution the projections upon it leave the 3
feed bar, which drops, and is brought to its original position by the
spring in its forked end. In order to regulate the extent of its lateral
travel an adjustable stop is arranged by which the distance to which it
is forced back by the spring is regulated.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Alfred Johnson in the Great Seal Patent Office
on the 11th March 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALFRED
JOHNSON, of the British, Foreign, and Colonial Patent Office, Newhall
Street, Birmingham, in the County of Warwick, send greeting.
$
WHEREAS Her most Excellent Majesty Queen Victoria, by Her.
Letters Patent, bearing date the Eleventh day of September, in the
year of our Lord One thousand eight hundred and seventy-three, in
the thirty-seventh year of Her reign, did, for Herself, Her heirs and
successors, give and grant unto me, the said Alfred Johnson
Her special licence that I, the said Alfred Johnson, my executors,.
administrators, and assigns, or such others as I, the said Alfred
Johnson, my executors, administrators, and assigns, should at any
time agree with, and no others, from time to time and at all times
thereafter during the term therein expressed, should and lawfully might
make, use, exercise, and vend, within the United Kingdom of Great
Britain and Ireland, the Channel Islands, and Isle of Man, an Invention
for "IMPROVEMENTS IN SEWING MACHINES," upon the condition (amongst
others) that I, the said Alfred Johnson, my executors or administrators,
by an instrument in writing under my, or their, or one of their hands
and seals, should particularly describe and ascertain the nature of the
said Invention, and in what manner the same was to be performed,
and cause the same to be filed in the Great Seal Patent Office within
six calendar months next and immediately after the date of the said
Letters Patent.
NOW KNOW YE, that I, the said Alfred Johnson, do hereby
declare the nature of my said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained
in and by the following statement and accompanying Drawing (that
is to say) :-
This Invention relates to improvements in that form of sewing
machine in which one thread only is used, and a succession of stitches is
formed by means of a hook or looper vibrating or partially rotating
backward and forward, the point of which enters the loop formed by the

page_text: needle in the usual way below the fabric which is being sewn, and
having opened such loop sufficiently retains it until the needle again
enters it after having been withdrawn from the work and then re-
penetrated it, for the purpose of making a fresh stitch in such new
position as the work has been advanced to by the action of the feeding
mechanism.
My improvements consist of a novel method of constructing,
arranging, guiding, and actuating the bar or frame which carries the
needle; of a novel method of forming and actuating the hook and its
adjuncts by which the loops formed by the needle, as described, are
formed and the stitches formed; and of a novel method of constructing
and supporting the "pressers" by which the work is kept down upon
the table or work plate of the machine. By my improvements such
sewing machines are made more simple, cheaper, and certain in their
operation than in chain sewing machines as heretofore constructed and
used.
For the
purpose of carrying out my Invention I take a framework of
any suitable material (but preferably of cast iron) which forms the bed
of the machine, and may be screwed, clamped, or otherwise secured to a
table or stand or other suitable foundation. One end of this frame-
work (which I call the front end) has one or more suitable projections
formed upon or attached to it to support and hold by means of screws
the table or work plate, over which the work passes in the usual way.
The other end of the framework (which I call the back end) has formed
upon or attached to it a suitable bearing, in which revolves one end of
a driving shaft or axle, the outer end of which passes through and
revolves in a bearing formed in the projection which carries the table at
the front end of the framework. The end of the shaft which passes
through the bearing at the back end of the machine has keyed or fixed
upon it a toothed pinion, which is driven by a larger toothed wheel
revolving upon a centre screwed into the upper part of the projection
adjoining it at the back end of the framework, as already described.
Instead of toothed wheels pulleys connected by an endless band or cord
may be employed; and the larger toothed wheel is driven by a handle
connected to it or by a crank and treadle in the usual way. Or the
shaft may be driven by a suitable pulley fixed upon any convenient part
of its length, and driven by an endless band or cord. The wheels or
pulleys described may be covered by an ornamental casing screwed to

page_text: the framework, which casing may also serve to support the bearing upon
which the larger wheel or pulley revolves.
Immediately inside the bearing at the back end of the framework I
form upon the shaft a crank or excentric of suitable radius or throw,"
for the purpose of driving the needle bar, herein-after described,
vertically up and down. This needle bar consists of a horizontal bar or
arm of suitable size and material (but preferably of malleable cast iron),
having formed upon or attached to its front end a vertical bar or arm,
the lower end of which carries a vertical straight needle of the kind
ordinarily used in sewing machines, and attached to the arm by means
of a bolt or screw.
The back end of the needle bar has formed upon or
attached to it a vertical bar or arm (which may be made open or hollow
to diminish its weight), the lower part of which is provided with guides,
guiding holes, or notches, which fit and slide up and down upon one or
more (but preferably two) vertical guide bars, the lower ends of which
are supported by the plate forming the bottom of the framework of the
machine, and the upper ends are supported by one or more brackets or
projections formed upon or attached to the upper part of the projection,
already described, at the back end of the framework of the machine.
The lower part of the vertical arm at the back end of the needle bar is
provided with a horizontal transverse slot arranged at a suitable height
and of sufficient length and width to fit over the excentric on the pin of
the crank upon the driving shaft, as already described. By this method
of construction and arrangement the needle bar being in a position
parallel with but vertically above the shaft is made to rise and fall
vertically at each revolution of the latter.
I prefer to make the slot described (within which the crank pin or
excentric works) open at one end for the greater convenience of
removing and replacing the needle bar, and I arrange the vertical guide
bars and guides at a sufficient distance laterally (in front view) from
the centre line of the needle bar and shaft, so that the needle bar may
escape them in its vertical up-and-down movements. A spring may be
used, if desired, to aid the upward movement of the needle bar. The
front end of the shaft has formed upon it or attached to it, after passing
through its bearing) a disc carrying a crank pin, which enters a slot or
recess formed in the back of a vibrating hook or looper, the lower end
of which is pivotted upon a screw fixed to the front of the projection,
already described, at the front end of the framework. The hook or

page_text: looper is thus made by the revolution of the shaft to vibrate backward
and forward upon its lower centre, and I make the slot or recess in the
back of the hook of a curved form, and I adjust the relative position
of the crank pin which drives it, and of the crank or exentric which
drives the needle bar, so that the entrance of the point of the hook or
looper into the loop formed under the work by the needle may be
exactly at the right moment to form the stitch.
The point of the hook or looper is formed in the method and shape
well understood and practised for forming the stitches in chain stitch.
sewing machines, but in order to ensure the unfailing entrance of the
point of the needle into the loop formed by the hook I attach to the
front of the latter a supplementary elastic hook, preferably of steel wire,
the point of which is pressed closely against the side of the point of the
principal hook (in a recess in the side of which its point may lie) so that
both enter the loop of the thread together, but after touching at their
points the supplementary hook separates from the other laterally (in
plan) so as to open out the loop of thread upon them and thus secure
the certain entry of the needle point between them into the loop when
making the next stitch. When the hooks are again retracted (by the
continued revolution of the shaft) after the needle has so entered the
loop the elasticity of the supplementary hook allows it to separate from
the principal one sufficiently for the needle and thread to pass between
their points. I prefer to attach the supplementary hook to the principal
one at a point near the centre on which the latter turns. The foot
which presses the work upon the table or work plate of the machine
may be made in the usual well understood way, but I prefer to attach it
to the lower end of a vertical bar, the upper end of which is fixed to
the front end of a flat horizontal elastic bar or spring, the back end of
which is screwed or otherwise attached to the projection already described
at the back end of the framework of the machine. I sometimes make
the vertical bar to which the presser is attached pass or slide through a
suitable guide formed upon or attached to the vertical bar to which the
needle is fixed.
The apparatus used for. feeding the work forward over the table or
work plate of the machine may be of any of the well understood kinds
ordinarily used in sewing machines, but I prefer to use a feeding bar,
the upper edge of one end of which or of a plate attached to it carries
projecting angular teeth which pass through a suitable opening in the

page_text: work plate of the machine adjacent to the hole through which the
needle works. The other end of the feeding bar has a horizontal slotted
or forked end, which turns on and slides upon a screw fixed to the front
of the projection which carries the work plate. Between the screw and
the inner end of the slot I arrange a spring, the elasticity of which tends
constantly to force the feeding bars in the direction of the needle.
Upon the shaft between the front bearing and the back of the disc
which carries the pin driving the hook or looper I form or fix the pro-
jections or excentrics, one adjoining the bearing and the other adjoining
the back of the disc. One of these projections or excentrics is so
arranged that it lifts the teeth upon the upper edge of the needle bar
through the opening in the table or work plate at the exact moment
when the feed forward of the work is required to take place (that is to
say when the needle is lifted completely out from the work), and the
other projection or excentric is so arranged that at the same moment its
edge presses against a corresponding vertical projection upon the feed
bar which is thus forced forward, and the work is thus fed along, the
spring in the slot of the feed bar being at the same time compressed.
As the shaft continues its revolution the projections or excentrics upon
it leave the feed bar, which drops and is brought again to its original
position by the elasticity of the spring in its forked or slotted end.
In order to regulate the extent of the lateral or backward and forward
movement of the feed bar, and thus the length of the stitches, I arrange
an easily adjustable stop by which the distance through which the feed
bar is forced back by the spring as described is regulated. I prefer to
make the driving shaft in two parts, one of which is screwed or otherwise
fixed into the other in order that it may be more readily fitted and
adjusted in the bearings in which it works. The thread is supplied to
the needle in the usual way from a reel, which may be placed upon a
wire fixed upon the framework of the machine. The crank or excentric
which drives the needle bar may be concealed by a casing either forming
part of the framework of the machine or attached to the latter by screws
or otherwise.
The accompanying Drawing is in illustration of my Invention.
Figure 1 is a plan; Figure 2 a side elevation partly in section: and

page_text: a is the framework of the machine shewn fixed upon a base 6. The
driving shaft e revolves in bearings formed in the projections d, d', upon
the framework a, and carries at its back end the toothed pinion e which
is driven by the wheel turning upon the screw g. The wheel fis
shewn turned by the handle h, and the wheel fand pinion e are enclosed
in the casing i. The bent needle bar k has the needle fixed into the
lower part of its front end by the screw 1, and has formed upon its back
end the guides m, m, m, m, which slide vertically upon the two guide
bars n, n¹, the lower ends of which are fixed to the framework a, and
their upper ends to the projection o. The lower part of the back end
of the needle bar k also has formed upon it the transverse slot p (shewn
in Figure 4, which is a back view of the needle bar) in which works the
pin of a crank formed upon the driving shaft c, the revolution of
which thus causes the needle bar to rise and fall. The front end of the
driving shaft c after passing through the bearing d¹ carries the disc in
which is fixed the crank pin t. The curved hook or looper u turns
upon the centre v, and is made to vibrate by the crank pin t which
enters a curved slot or groove w formed in the back of the hook u, as
shewn in Figure 5, which is a back view of the hook or looper. The
hook or looper u has a supplementary wire on the metal hook u¹
attached to it, the two hooks meeting at their points but then separating,
as and for the purpose already described, and as shewn in Figures 2
and 3, and in Figure 6, which is a plan of the looper and its supple-
mentary hook. The presser foot x is shewn down upon the work plate y
by the spring z.
1°
A is the feeding bar having a slot B turning and sliding upon the
screw C, between which and the end of the slot the spring D is placed.
The bar A is actuated by the projection or excentric cams, shewn in
dotted lines at, E, Figure 4, one of which raises and lowers the feeding
bar, and the other moves it laterally by pressing against the vertical
projection upon it, F. G is an adjustable stop by which the movement
of the feeding bar can be regulated; H is a tension screw for regulating
the tension of the cotton which is supplied from a reel placed upon the
wire K.
Having now described my Invention and the manner in which it is

page_text: guide bars and guides, substantially as described and shewn in the
Drawing.
Also the supplementary elastic hook attached to the curved hook or
looper, substantially as and for the purpose described and shewn in the
Drawing.
Also the method of driving the curved hook or looper with the supple-
mentary elastic hook attached by means of a curved slot in the hook or
looper, in which slot a crank pin works driven by the driving shaft.
Also the combination with the needle bar rising and falling vertically,
as described, and with the curved hook or looper and supplementary
elastic hook of the feeding bar driven by projections or excentrics upon
the driving shaft, and returned to its place by a spring, substantially as
and for the purposes described and shewn in the Drawing.
Also the presser foot attached to an elastic plate or bar, substantially
as described and shewn in the Drawing.
Also the general arrangement of the parts of the sewing machine,
substantially as described and shewn in the Drawing.
In witness whereof, I, the said Alfred Johnson, have hereunto set
my hand and seal, this Tenth day of March, in the year of our
Lord One thousand eight hundred and seventy-four.