Improvements in Stitch Forming Mechanism for Sewing Machines.
Year: 1890

page_text: Date of Application, 24th Dec., 1890
Complete Specification Left, 18th Sept., 1891-Accepted, 24th Oct., 1891
PROVISIONAL SPECIFICATION.
Improvements in Stitch Forming Mechanism for Sewing Machines.
I, THOMAS WEBB, of Waterloo Road, Stockport, in the County of Chester,
Manufacturer, (a communication to me by Thomas W. Bracher, of New York,
U.S.A., Manufacturer,) do hereby declare the nature of this invention to be as
follows:-
This invention relates to that class of sewing machines in which a loop is carried
by means of a looper over and around the edge of the article to be stitched and is
more particularly intended to be used in the manufacture of hat sweats and similar
articles though it may be advantageously used for other purposes.
The object of the invention is to provide a stitching mechanism wherein two
threads are employed one thread carried by a shuttle and the other thread carried
by a needle and acted upon by a looper in such a way that two loops are formed.
which are locked together by incans of the said shuttle thread.
The invention consists in a stitch forming mechanism composed of a thread
carrying needle and its operating mechanism; a looper and its operating mechanism;
and a thread carrying shuttle and its operating mechanism all arranged and adapted
to form two loops one passing over the edge of and one passing through the article
to be stitched, and to lock said loops together by the shuttle thread.
The machine is constructed with a bed or table; a revolving presser foot; a
revolving feed; a revolving shuttle a needle bar and needle are of usual or
ordinary form.
Upon the bed plate is fastened a looper head or bracket which carries a looper
mounted upon a rocking shaft. The motion to be communicated to this rocking
shaft from the driving gear should be such as to carry the looper through a path
of about a semi-circle, as the looper must pass beyond the line of the needle both
above and below the bed-plate: above to take the thread from the needle, and
below to carry the thread now formed into a loop, to a position where the needle
and needle loop can pass through it.
Various mechanism for connecting the rocking shaft with the driving gear so as
to produce the desired amount of swing may be employed but at present I prefer to
affix to the outer end of the rocking shaft an arm which carries a roller or sliding
block and stud, and which roller or sliding block moves in a slot formed in a pivoted
arm. This arm is preferably pivoted at the top of the looper head (but may be
pivoted at any other convenient position) and is caused to swing or rock upon its
pivot by a connecting rod from the driving gear in passing round a small stud on
the looper arm.
The distance of the centre of the roller or sliding block from the centre of the
rocking shaft should be about half the length of the pivoted arm from the pivot to
the lower end of the slot.
As the pivoted.arın.swings to-and--fro-the-arm is moved and the roller or sliding
block is caused to move along the slot and thus communicates the desired amount
of motion to the looper.
In operation the mechanism works as follows.
The article to be stitched being inserted between the presser foot and feed the
machine is started and the needle with its thread begins to descend:
The looper catches the thread before the needle enters the article and by its.
movement carries the thread under the bed plate in advance of the needle and holds
the thread in the form of a loop in the path of the descending needle. The needle
and its loop pass through the article and through the loop formed by the looper
then offering the needle loop to the point of the revolving shuttle which opens the

page_text: needle loop and carries the thread round the bobbin so that the shuttle thread
passes through the needle loop. The slack is now taken up by the take up
mechanism in the ordinary manner the needle returning to its initial position
followed by the looper.
Instead of the roller and sliding block movement for the rocking-shaft other
means such as links or rack and pinion may be employed to actuate the rocking-
shaft of the looper.
Dated this 22nd do. of Dhan
1
1000
COMPLETE SPECIFICATION.
Improvements in Stitch Forming Mechanism for Sewing Machines.
I, THOMAS WEBB, of Waterloo Road, Stockport, in the County of Chester,
Manufacturer, (a communication to me by Thomas W. Bracher, of New York.
U.S.A., Manufacturer,) 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:-
This invention relates to that class of sewing machine in which a loop is carried
by means of a looper over and around the edge of the article to be stitched and is
more particularly intended to be used in the manufacture of hat sweats and similar
articles though it may be advantageously used for other purposes.
The invention is designed with the object of providing a stitching mechanism
having two threads one thread carried by a shuttle and the other thread carried by
a needle wherein the needle thread is acted upon by a looper in such a way that
two loops are formed which are locked together by means of the said shuttle thread
to produce the stitch which forms the subject matter of my Patent No. 21028 of
even date.
It consists essentially in a stitch forming mechanism composed of a thread
carrying needle and its operating mechanism; a looper and its operating mechanism;
and a thread carrying shuttle and its operating mechanism; all arranged and
adapted to form two loops one passing over the edge of and one passing through
the article or material and to lock said loops together by the shuttle thread.
It will be fully described with reference to the accompanying drawings in which
are also shown the stitch produced which forms the subject matter of iny Patent
No. 21029/90 of even date.
Fig. 1, is a top or back view of over-seam made with my improved stitch
(enlarged to an exaggerated scale).
Fig. 2, is the underside of same.
Fig. 3, side elevation of improved stitching mechanism showing the loop former
above the bed plate.
Fig. 4, side elevation with the loop former below the bed plate.
Fig. 5, end elevation.
The stitch is formed on the edge of the material A by two threads-the loop
thread B and the locking thread C-and may if desired be formed by hand though
it is preferred to use the mechanism shown in the drawings in conjunction with a
shuttle sewing machine of ordinary construction.
The loop thread B is carried by the needle D of the machine and the locking
thread C is carried by the shuttle.
The loop thread B is formed into two distinct loops a and the first loop a is
carried over the edge of the material A by a loop former E to such a distance on
the under-side thereof that the second loop when passed through the material with
the needle necessarily passes through the bight of the first loop.
The locking thread C is then passed through the bight of the second loop bin
the loop thread B formed around the needle eye and when the threads are drawn

page_text: tant they produce a perfect lock stitch the locking thread C being firmly grasped
by the bight of the second loop 6 (as shown in Fig. 2) and the first loop a being
held in position by the second loop and the locking thread C.
The loop former E is carried in a head or bracket affixed to the bed plate or
table G of the machine which in the example shown is provided with a revolving
presser foot a revolving feed I and a revolving shuttle J which carries the locking
thread C the loop thread B being carried by the needle D. Kis the needle bar.
These parts are of ordinary construction and are operated in the usual way.
The head or bracket F of the loop former E is fastened to the bed plate or
table G and carries the loop former mounted on one end of the oscillating shaft e.
The movement of the loop former E should be about half a revolution in a semi-
circular path first in one direction and then in the opposite direction as the loop
former must pass beyond the vertical line of the needle both above and below the
bed plate Gabove to engage with the loop thread B and take it from the needle D
and below to carry the loop a thus formed in the thread below the material A and
to a position where the needle and the second loop 6 formed at the needle eye can
pass through it.
Motion is given to the oscillating shaft e through a crank or arm L affixed to its
outer end affixed to which on a small stud is a roller or sliding block 7. The roller/
engages with a slot m in a swinging arm or lever M pivoted at f to the head or
bracket F. The arm M is connected to and receives motion from the driving gear
of the machine by a connecting rod which moves to and fro and is connected thereto
by the stud N.
The distance of the centre of the roller or sliding block from the centre of the
oscillating shaft e should be about half the length of the pivoted arm M from the
pivot to the lower end of the slot.
As the pivoted arm M is moved to and fro the roller slides up and down in the
slot m and the desired movement is thereby communicated to the oscillating shaft e
and loop former E.
Various mechanism for connecting the oscillating shaft e with the driving gear
so as to produce the desired amount of swing may be employed but at present I
prefer the mechanism shown in the drawings though instead of the sliding roller
and block working in conjunction with the slot in the pivoted arm M links or a
rack and pinion or other similar means may be employed to give the oscillating
movement to the shaft e of the loop former E.
In operation the mechanism works as follows:-
:-
The material A being inserted between the presser foot H and feed mechanism I
the machine is started and the needle with its thread begins to descend. The loop
former E catches the thread B before the needle enters the material and by its
movement carries a loop a of the thread under the bed plate G in advance of the
needle D and holds the loop in the path of the descending needle. The needle and
its loop & pass through the material and through the loop a formed by the looper
then offering the needle loop b to the point of the revolving shuttle which opens the
needle loop and carries the thread round the bobbin so that the shuttle thread C
passes through the needle loop. The slack is now taken up by the take up
mechanism in the ordinary manner the-needle returning to its initial position
followed by the looper.
A neat appearance on the upper side of the seam is produced as the two threads
which pass over the edge lic close together and run in substantially parallel lines,
so that they present very much the appearance of a single thread.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed I wish it to be understood
that I make no claim in this Specification for the stitch produced as that forms the
subject matter of my Patent 21028 of 1890 but I declare that what I claim is :-
1. The combination with a sewing machine of an oscillating loop former placed
on the table of the machine which engages with the thread from the needle and

page_text: carries it in the form of a loop round the edge of the material to the under side
thereof holding it there until the needle and second loop of the thread pass through
it substantially as described.
2. The stitch mechanism for forming two loops in the thread one loop to pass
over the edge of and the other through the material which are locked together by
the shuttle thread constructed and arranged substantially as described and shown.
Dated this 17th day of September 1891.
WM. P. THOMPSON & Co.,
Manchester, Liverpool, and London, Patent Agents.
WM. P. THOMPSON & Co.,
Manchester, Liverpool, and London, Patent Agents.