IMPROVEMENTS IN SEWING MACHINES
Year: 1872

page_text: LETTERS PATENT to George Tomlinson Bousfield, of Loughborough
Park, Brixton, in the County of Surrey, for the Invention of
“IMPROVEMENTS IN SEWING MACHINES."-A communication from abroad
by James Alford House, residing at Bridge Port, State of Con-
TTd Shat
COMPLETE SPECIFICATION filed by the said George Tomlinson
Bousfield at the Office of the Commissioners of Patents, with his
Petition and Declaration, on the 8th March 1872, pursuant to
the 9th Section of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
TOMLINSON BOUSFIELD, of Loughborough Park, Brixton, in the County
of Surrey, send greeting.
WHEREAS I am in possession of an Invention for "IMPROVEMENTS
IN SEWING MACHINES," and have petitioned Her Most Excellent Majesty
Queen Victoria to grant unto me, my executors, administrators, and

page_text: Figures 13 and 14 are respectively an elevation and plan of a modified.
form of hook and of a contrivance for forming or opening the loop,
which is to be seized and drawn out by the revolving hook.
This machine has no pad or other apparatus for detaining the loop of
needle thread below the cloth after it has been cast off by the hook. It.
has a take-up apparatus, and its hook moves with a velocity differing
during each revolution from that of the main shaft, although it makes.
the same number of complete revolutions per minute. The needle.
moreover is in the best form of the machine, not driven by a crank.
motion, but by contrivances which permit it at times to pause entirely.
or move upward or downward very slowly, somewhat as in shuttle.
machines, and the hook has several peculiarities herein-after described...
In all these points the machine differs from the ordinary Wheeler and
Wilson machine.
:
In the drawings the frame of the machine is represented at a, ; in
it is mounted a horizontal shaft b, b, carrying the needle-driving cam b¹
and the take-up cam c. The needle cam is grooved and acts upon a
roller b² mounted in the lower end of the bent lever b³ pivotted at b*, and
the front end of the lever, by means of a short connecting rod, is attached
to the needle arm or stock 65, which at its lower end carries the needle...
The groove in the needle cam is so shaped as to cause the needle to
pause in its ascent just after the loop has been seized by the hook, and
with the needle i at about the cloth level (by preference below the cloth).
until the hook has expanded the loop, and I find this pause advantageous;
because it prevents the hook from drawing thread through the eye while
it is moving or stationary in the cloth or leather, and in sewing leather,
or heavy starched fabrics such drawing either frays or cuts the thread,
unless the needle is so large that it makes bad work.
,
The machine will sew ordinary woven fabrics well when the needle
has no pause, and I propose at times to construct the machine with the
needle moved by a crank or equivalent motion. I intend at times to.
apply any of the mechanical devices known or used to drive sewing
machine needles so as to permit them to pause or move very slowly up
or down, in place of the rotating cam specially described and shewn in
the Drawings. By examination of the Drawing it will be perceived that
the cam groove is of a wedge shaped section and that the roller lying
therein is a frustrum of a cone. This construction causes the groove.

page_text: and roller to wear more evenly, and enables me by adjusting the roller
to take up any slack arising from wear.
The take-up lever c¹ is arranged (sec Figure 1) between the needle
lever and the bracket arm, which makes part of the frame. It is pivotted
near its centre to the bracket and provided at its forward end with two
hooks or eyes, through which the needle thread passes; its rear end is
pivotted to a connecting rod c (see Figures 1, 7, and 8), which is forked
near its lower end so as to straddle the main shaft, and there carries a
roller which is acted upon by the cam c. When thread is passed
through the eye or eyes in the forward end of the take-up lever and
through the needle eye the drag of the thread keeps the roller in contact
with the cam, the front end of the lever descending by means of the pull
or drag of the needle thread upon it, and the same end ascending to act
as a take-up by reason of the action of the cam upon the roller. This is
the take-up I prefer, but other known take-ups of various kinds may be
substituted for it.
The machine is fitted with a cloth supporting plate or table d and a
presser foot d' provided with an ordinary presser spring and cam, all as
usual; it has also a four-motion rough surface feed, the roughened
surface d³ being mounted upon an ordinary feed bar d³, actuated as usual
by a retactile spring and cams d*, d³, (see Figure 9) mounted upon the
hook shaft, all as usual. The hook shaft e lies by preference in line of
the main shaft and upon it is mounted the hook, which is driven with a
speed changing during each revolution of the main shaft, the hook
moving faster than the main shaft while seizing and expanding the loop,
and slower after the loop is cast off and while it is being taken up, thus
giving time not only for the take-up to act properly but also for the
operations of the needle as herein-after described.
There are many known contrivances for thus imparting to one shaft
by means of another shaft a differential motion or motion varying in
velocity during each revolution from that of the driving shaft, and I
intend to use any of such known contrivances in this machine, but I
prefer one of my own invention, now to be described :-To the end of
the main shaft is secured a disc f; this disc has projecting from it a
pin f¹ (a crank and crank pin would serve the same purpose); this pin
enters a slot f* (see Figure 6) in a disc ƒ³, which I call the differential
disc; this disc is supported by and free to revolve in a journal bearing

page_text: or pillow block f*, which is secured to the bed plate, and I prefer to
make it adjustable transversely to the main shaft, attaching it by means
of screws passing through slots or in any other proper known way which
will permit adjustment in planes perpendicular to the axis of the disc.
This same disc has in it another slot f³, and into this slot enters a pin e³
projecting from a disc e³, which is mounted upon the hook shaft e. It
is obvious that the disc f when revolved will, through the pin f¹, revolve
the differential disc fs, which latter acting by means of its slot f³ upon
the pine will cause the disc and consequently the hook shaft and
hook to revolve, and if the differential disc have its centre or axis in line
'with the axis of the hook and main shaft then these shafts will revolve
with the same angular velocity, but if the differential disc be moved out
of line then the pin f¹ will sometimes act nearer to, sometimes further
away from, the centre of the differential dise, and will thus cause it to
move alternately faster and slower than the main shaft. This same
sidewise adjustment of the differential disc will cause different localities
in the groove f to act during the same revolution upon the pin e², so
that the shaft e will move differentially in relation to the differential
disc f³, and if the slots be as shewn, straight and on the same diameter,
then the variation of the velocity will be intensified, so that when fis
moving faster than then at that vary time e will be moving faster than
fand vice versa.
The further the differential disc is moved out of the
shaft line the greater will be the difference of velocity between the
motions of the main shaft and the hook. Two straight slots in the
differential disc, both cut on the same diameter, serve all necessary
purposes in the present machine, but I intended to use slots either
straight or curved and with various angular relations to each other. The
differential disc enables me to locate both the driving and driven shaft
in the same line, to dispense with all cogs or connecting rods, and to
adjust the variations of velocity while the parts are unaltered in their
construction.
The bobbing of this machine lies within the periphery of the hook as
usual, but this, as reference to Figures 4, 10, 11, and 12 will shew, is
thicker at the centre and much thicker at the periphery than usual, and
lies in a case like a pill box cover with a rounded top, which is provided
with a series of small holes through which the bobbin thread may be
passed so as to attain a proper tension upon the lower thread. The top
may be cut away as from ≈, 5, Figure 11, and the case will then be a

page_text: ring with an inwardly projecting flange. This bobbin is held in place
partly by the hook and partly by a bobbin ring / as usual, but instead
of mounting the latter upon a slide I prefer to mount it upon a hinge, so
that it will swing out as in Figure 5 when it is required to remove or
replace a bobbin, and may be swung rearward so as to confine the
bobbin. A set screw ² serves to limit the rearward movement of the
swinging arm, so that the ring confines the bobbin without bearing upon
it. I prefer to make the ring proper or the acting part thereof of steel
and held in its supporting arm as shewn (see specially Figure 4), and
also to notch it slightly, as shewn at h³ (see Figure 3), so as to take a
small boss upon the bobbin case and prevent it from turning, but both
the boss and the notch are refinements of the construction necessary in
theory but practically unimportant. I also prefer to form the ring so.
that it is furthest from the face of the bobbin on that side thereof where
the cast-off loop slips up under the operation of the take-up, so as to
prevent the loop from being pinched while being drawn up.
.. The hook is as a whole an irregular hollow conical frustrum supported
on a dished base plate k¹, with the bobbin lying in the cavity or hollow
as usual. The seizing part of the hook is shewn at m; just behind it,
sunk into the surface of the cone, is the groove n, which vanishes away :
upon the conical surface and first receives one part of the bight of needle
thread and then guides it to the front of the hook, whence it leads over
the front of the bobbin as usual.
At o the edge face of the hook recedes, permitting that part of the
bight behind the bobbin to lead up in a straight line toward the needle
eye preparatory to drawing up the loop, but the line of recession does
not extend directly to the base plate, which lies behind the bobbin, but
makes a sort of step (sec specially Figure 9) at p before the conical
surface disappears entirely. The cone then ceases to exist through an
angle of some 30° or 40°, more or less, and then reappears at q and
extends out as at r.
In Figure 13 the form of hook is slightly modified; the line of
recession from o extends directly to the base plate at p, and there is a
gap p, q, cut down below the level of the base plate.
The loop is cast off when the two parts forming the bight thereof lead
upward through the gap or space bounded on two sides by the projections
at p and q, and the two projections p and q overlie the bobbin and

page_text: prevent it from being lifted upward. This is the function of these two
projections, and they in conjunction with the passage between them are
a new feature in revolving hooks.
That portion of the hollow conical frustrum which commences at q
gradually increases to its full hight, as at r, and continues nearly at
full height to s, but at the rear of the frustrum is cut away (sce
specially Figure 3), thus forming a hook which points in the opposite
direction to and lies in front of the seizing hook. The hook shaped
projection s is further from the axis of the hook shaft than the seizing
hook, and this peculiarity ensures the passing of the cast-off loop behind
it when pulled up by the take-up apparatus. This hook does not act as
a hook, but on the contrary is formed and located so as to prevent the
cast-off loop from catching while being drawn up; it is in fact a guard.
I found the projection r to be essential, and made hooks with that
projection and with no guard like s, but I discovered that the cast-off
loop then frequently caught upon the projection 1, thus breaking or
fraying the thread, and after many attempts to remedy this defect hit
upon the plan of prolonging the projection 7 until it overlapped the point
of the seizing hook. This construction leaves a narrow throat (sce
specially Figures 3 and 14) between 8 and the seizing hook, and one part
of the loop when cast off lies in this throat and is pressed rearward by
the rear side of the guard 8, so that it cannot catch upon 7. The
Drawings shew an annular groove surrounding the hook; this groove
was cut for the needle point to lie in during the rotation of the hook.
It being my intention usually to draw out the loop while the needle
eyc lies below the cloth, I have in the modifications, Figures 13 and 14,
represented the hook shaft as lowered a little, and am thus enabled to
dispense with this annular groove. This lowering of the hook shaft is a
; convenience in construction, but in actual use I found that the loop
was apt to open above the seizing point or behind the needle, thus
occasionally causing a mis-stitch. I have remedied this defect by the
use of the loop opener or loop former w, which is a piece of metal lying
upon the periphery of the hook and attached to the frame by a spring w³,
so that the loop former always rides on the periphery of the hook. This
former has a hole or notch in it open to the front, and the construction

page_text: is such that the thread behind the needle bears against the rear or
bottom of this slot as the needle rises. This friction of the thread upon
the opener forms the loop in connection with the friction of the cloth
upon the thread, and the opener throws the formed loop forward and in
the path of the seizing hook.
In the operation of the machine the needle thread is led from the
spool y through the eye y¹, thence through the tension apparatus x,
thence through y upward to one of the eyes in the take-up lever,
thence downward through y³, and up again to the other eye in the
take-up lever, thence down again through a long eye or slit in the
piece at of the bracket arm a, and thence through the needle eye, and
the bobbin is wound, put in its case, and the case into the cavity of the
hook by preference with the bottom of the case in front or nearest the
ring. The bobbin thread leads out through the holes in the case, the
needle descends, rises a little, and pauses. While it stands still or
nearly so the hook seizes and expands a loop of needle thread, puts it
around the bobbin, and casts off the loop, this being performed while
the hook is moving with greatest speed. Then the needle rises rapidly,
and the take-up acts, at the same time pulling up the cast-off loop.
The needle arm descends again, pierces the cloth, and rises a little,
and during the time occupied by the needle in rising, descending and
rising again a short distance to spread the loop, so that the hook can
seize it, the hook makes about one-half a revolution, only moving then
at its slowest speed. The differential movement of the hook therefore
affords time for the proper performance of all their duties by the needle
and take-un.
Third. I claim a bobbin ring when mounted upon a
hinged arm,

page_text: gap as specified.
Fourth. I claim a differential disc in combination with two pins
taking into grooves therein, one pin being secured [to a driving and the
other to a driven shaft, and the whole being and acting, substantially as
set forth, to cause one shaft to be moved by another with a differential
velocity.
Fifth. I claim a differential disc mounted in a pillow block capable of
sidewise adjustment, substantially as specified, in combination with two
shafts and a pin on each of them entering slots in the differential disc,
whereby one shaft can be caused to revolve at a differential velocity by
motion derived from another shaft, and the difference of velocity can be
augmented or diminished by adjustment of the disc.
Sixth. In combination with a hook revolving with a differential
velocity upon an axis lying in a horizontal plane, and a needle acting
in a vertical plane, I claim a take-up apparatus, the combination being
substantially such as herein described.
Seventh. In combination with a hook provided with projections to
prevent the lifting up of a bobbin, and revolved by means of apparatus
which gives it a differential motion, substantially such as herein described,
I claim a needle operating with a pause in its motions, substantially as
described, the combination being substantially as set forth.
Eighth. In combination with a needle actuated by mechanism, sub-
stantially such as set forth, which causes it to pause after it has risen
a short distance, I claim a hook rotating in a vertical plane, as described,
by means of mechanism which imparts to it a differential velocity and
a take-up apparatus, substantially such as described.
Ninth. I claim a loop former, substantially such as is described, in
combination with a revolving hook for seizing and expanding loops of
needle thread, the former acting to open the loop seized by the
latter.
Tenth. I claim a revolving hook made with projections to prevent
the lifting of the bobbin, and a guard overlapping the seizing hook,

page_text: meaning hereby to claim a rotating hook for operating upon the needle
thread of a sewing machine constructed in all respects substantially as
herein-before described.
In witness whereof, I, the said George Tomlinson Bousfield, have
hereunto set my hand and seal, this Twenty-third day of 5
January, One the year of our Lord One thousand eight hundred
and seventy-two.