Improvements in Sewing Machines.
Year: 1899

page_text: Date of Application; 2nd Mar., 1899-Accepted, 29th July, 1899
COMPLETE SPECIFICATION.
Improvements in Sewing Machines.
I, ERNEST CHARLES LEA, of 4, Silverdale, Surbiton-Road, Kingston-on-Thames,
in the County of Surrey, Engineer, do hereby declare the nature of this invention
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:-
My invention relates to sewing machines for forming either lock or chain
stitching.
And in order, that my invention may be thoroughly understood I now proceed
to describe the accompanying drawing thereof, reference being had to letters and
figures marked thereon.
Fig. 1, is a vertical section of the machine.
Fig. 2, is an end elevation.
Fig. 3, is an enlarged size of the lever guide and cam viewed from the right
hand of Fig. 1.
Fig. 4, is a back view of the cam.
Fig. 5, is a front view of the shuttle to form a lock stitch.
Fig. 6, shows the back of Fig. 5.
Fig. 7, is a plan of the tension fixed in the inside of the shuttle.
Fig. 8, is an alternate spring m with cam head screw.
Fig. 9, is a spring with a tension, block.
:
Fig. 10, is a plan of the underside of the bedplate of the machine.
Fig. 11, is a side view of the shuttle or looper shutter.
Fig. 12, is a front view of Fig. 11..
.
Fig. 13, is a section on line X X of Fig. 10.
Fig. 14, is a section on line A B. Fig. 6, and section of carrier -k.
Fig. 15, is a plan and an elevation of the chain stitch looper.
In carrying my invention into practice I construct the apparatus with two
horizontal shafts cand.c¹. The shaft c actuates the needle bar through the
The edge of
medium of a roller 1 on the disc 2 engaging a slotted cam 3.
the disc 2 is shaped to form an eccentric cam, or the back of it is similarly
grooved, to actuate the "take-up". 4 which liberates cotton to form a loop for
The shaft e also
the shuttle to pass through and then recovers or takes it up.
actuates and controls the shaft in the following manner..
To an eccentric or crank on the top shaft c I attach a lever a having at
its lower end a pine carrying a cylindrical or spherical roller which engages in
a slot f in a cam on the lower shaft. At a point between the ends of the
lever is a ping which acts as a fulcrum and engages an angularly placed.
guide attached to the inside of the arm i of the machine.
The angular guide h may be on the lever a and the fulcrum pin g attached to
the arm of machine, if desired, the ultimate effect through the angularity of the
guide being, for practical purposes, identical.
I am aware that for many years motion has been transmitted from one shaft
to another through the medium of a' lever attached, by one end to a crank or
eccentric on one shaft and at the other end carrying a pin or roller engaging

page_text: with a slot or slide on a crank on another shaft and having either an inter-
mediate straight guide sliding on a fixed, fulcrum pin or a fulcrum pin sliding
in a fixed vertical straight guide which-I do not claim as any part of my invention.
In neither case (excepting with a lever having a fulcrum pin attached equi-
distant from the centre of motion either end) does the lower or pin end of lever
describe a circle when the top shaft is revolved, but an ellipse or egg-shaped
figure the vertical diameter of which is the same as the throw of the crank on
the driving shaft, while the horizontal diameter of the ellipse may be modified
by altering the position of the fulcrum.
As the figure obtained (excepting as noted above) in either case is not circular
the motion transmitted to the lever shaft is more or less non-synchronous with that
of the upper shaft and the amount of this intermittence can be materially
modified by placing the lower shaft more or less out of approximate centrality
to the figure described by the pin or lower end of lever, but the amount of this
displacement' is limited by the shape of the figure, as it is not practicable to run
the shafts at any but a comparatively low rate of speed unless the pin on -lever
describes a path or figure sufficiently distant at all parts from the centre of the
lower shaft to avoid excessive vibration, but with a straight guide the figure
described by pin on lever does not for this reason allow a sufficient displacement
of the lower shaft necessary to obtain the amount of intermittence of speed that
I require, combined with a high rate of rotation.
Requiring for the most advantageous use of the shuttle and looper herein
described a motion for a portion of the revolution of the lower shaft, c greatly in
excess of that of the upper ordinary shaft, I have invented the angularly
placed guide herein described, which, according to the angle at which it is
fixed, varies the figure described by the lower or pin end of lever a in a remark-
able manner.
As illustrated herein this guide is about at, an angle of 20° to a vertical
line through the centre of the top shaft and the figure described by the pin e
on end of lever is an inclined ellipse as shown by dotted lines in Fig. 3.
Increasing the angle of guide increases the long diameter and decreases the
short diameter of this figure while decreasing the angle has the reverse effect,
in each case the axes of the diameters are altered.
So that according to the angle at which I place the guide I am enabled to get
a motion at the lower end of lever which is in the form of an inclined ellipse
and either long and narrow or short and broad as I may require.
The position between the ends of lever a at which I place the fulcrum
is immaterial excepting in so far as it modifies the figure described by the lower
end of lever a, with a small throw crank or an eccentric on the top shaft a
longer proportion of leverage is required below the fulcrum than is shown.
The lower shaft & being required out of vertical plane with the upper shaft c
comes within the figure or path described by the pin e on lower end of leyer a at
about the point shown in drawing, Fig. 3.
Starting the motion of top shaft from the position shown in Fig. 3, and taking
it through 180° gives a motion in a reverse direction to the lower shaft through
about 280°, the remaining 180° of motion to complete a revolution of top shaft
producing 80° of motion on the lower shaft.
It will of course he understood that these intermissions of speed are not sudden;
but gradual, so that when the pin e on lever à is at the point marked a² Fig. 3,
the lower shaft is at its point of least motion or slowest speed.
By so adjusting the mechanism that the needle is descending into the work
while the lower shaft is going through its period of reduced motion I am enabled
to get over three quarters of a revolution of the lower shaft c¹ whilst the needle j
is on its upward course, thus enabling the shuttled to catch the cotton from needle
and pass itself through the loop whilst the needle is ascending.
The, lower cotton is drawn through its tension, whilst the shuttle d is at its
oint of least motion, and the feed operates at about the same time, and owing

page_text: to the power exerted on the lower shaft c', being then at its greatest, is very
steady and strong.
:
The shaft c actuates the shuttle carrier and the shuttle or looper, also the
feed mechanism. The degree of feed is regulated by a screw. 5 operating through
the crank 6, the rod 7 and the crank S to alter the leverage of the block 9 actuated
by a cam 10 on the shaft by raising or lowering the pivoted lever 12. The
feed teeth are raised and lowered by a cam 11 on the carrier or attached to the
back thereof.
The rocking lever 14 is pivoted to the lugs 15, and the rocking lever 18 is
pivoted to the lever 14 at 16, Figs. 10 and 13. The feed teeth 17 are fastened
to the lever 13 at the point shown in Fig. 13. The spring 18 pulls forward and
downward keeping the lever in contact with the cams 10 and 11.
The
The shuttle Figs: 5, 6, 14, is a short cylinder closed in at one end r excepting
for the centre which has a tube which is slotted at *. On the outside of the
cylinder is a hook to catch the cotton carried by the needle and this hook is
extended backwards and sloped off so as to assist in throwing the hooked cotton
round the shuttle. The other end of shuttle is furnished with a cover having
a pins fitting tightly by friction or spring pressure into the tube. The two
portions are held in one position with regard to each other by the stud or
projection on the pins engaging the slot in the tube. One portion of the
cover projects beyond the open or free edge of the shuttle and is formed or
shaped as y Fig. 15, the portion w being convex and the portion being concave
and merging into the projecting stud 2. The extreme diameter of cover is less
than the internal diameter of shuttle leaving an annular opening for the
cotton to come through whilst the shuttle is constantly revolving. The extreme
edges of the cover is turned inwards over the edge of the spool or cotton-holder u
and prevents cotton getting between the spool and the inside of the cover.
shuttle tension is intermittent and holds the cotton only while the stitch is being
formed. The tension spring and block operates through a slot in the edge.st
of the cover and presses the cotton between itself and the inner edge of the
shuttle as shown at t¹. The tension and means of adjustment are also shown
in Figs. 7, 8, 9. The shuttle or looper carrier or driver k is shown in section
in Fig. 14. It has a shallow cylindrical cavity y' and a raised bevelled rim y
having at sa slot into which loosely fits the stud 2 on the shuttle or the looper.
The projection y of the shuttle cover, or of the back of the looper. fits loosely
into y so that a loop of cotton, owing to the formation of the parts y and y,
will readily pass around the shuttle coming off around the stud 2 in the slot 4.
The shuttle or looper is held in position in the carrier or driver & Fig. 1, by means
of a hinged sunk shutter carrying a small spring which presses lightly
against the pin s. The shutter is locked or secured in position by a spring
hinged flap 7. Pressing the flap down allows the shutter to fall back and
liberates the shuttle or looper.
The shuttle is opened by pressing the end of the pin which pushes off the
cover attached to. it. The spool or cotton holder u fits loosely over the tube r
and fills the body of the shuttle:
The
For chain stitching the looper Fig. 15, is subsitiuted for the shuttle. It is
shaped very similarly to the shuttle, but the shaped projection. y and the stud. s
being precisely as in the shuttle and for the same purpose, but permanently
fastened to the edge of the body leaving no annular opening. There is in
addition to the hook and its sloped continuation a second hook broad at
the base and projecting beyond the edge of the body and over the stud s².
pointed end of the hook projects backwards and sideways away from the point of
the hook 2. The looper in its revolutions engages the hook 2 with the needle
cotton and passes it around itself until it is caught and retained by the hook v
the broad base of which spreads the loop open for the needle to come through for
the succeeding stitch; the looper continuing its revolution and after the needle
=

page_text: point has descended within the loop draws the latter to one side away from the
hook and then drops it.
The point of hook on shuttle is recessed somewhat from the edge of the
body so that it may not pick up the shuttle thread when passing it. The
hook on looper has a small groove at the broad base to allow it to pass the
needle without touching.
In the shuttle cover shown in plan in Fig. 7, the tension block m¹ and its
spring m are in one piece, but in Fig. 8, I describe a tension block m¹ and
spring m fastened at so as to have side play with an eccentric headed screw o to
regulate the pressure of the spring. In Fig. 9, I show a similar design to
Fig. 8, with the exception that I use a pivoted tension-block instead of the
tension block m¹.
The tail of the spring m projects inwards and bears lightly against side of
spool or bobbin, it is attached to the spring m for convenience of fastening both by
the one screw 7.
It is of course apparent that the sizes, proportions, and adjustment of the various
parts may vary considerably within the scope of my invention.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is
1
1. In a sewing machine the combination of the lever a and angular placed
guide and fulcrum pin g and cam engaging a pin
e on the lever a to convey
motion from the crank on the driving shaft e to the lower shaft e the said pin e
operating in a slot f, substantially as herein described and according to the accom-
panying drawing.
2. In a sewing machine the combination of the shuttle carrier k shutter ¹
and flap l
3. In a sewing machine the combination of the looper Fig. 15, the carrier k
shutter and flap 7.
4. In a sewing machine a cylindrical rotating shuttle d having a shaped cover s³
stud s² pin s stud tuber slot hook and tension m m¹ or p.
5. In a sewing machine a cylindrical rotating shuttle with an annular opening t.
6. In a sewing machine the carrier k with a raised edge y2 and the slot st.
7. In a sewing machine the looper Fig. 15, with the hook the hook v the
back and the stud s².
8. The sewing machine substantially as above described in this Specification
and illustrated in the accompanying drawings.
Dated this 2nd day of March 1899.
J. P. BAYLY,
18, Fulham Place, London, W., Agent for the Applicant.