AN IMPROVED METHOD OF EFFECTING HEM-STITCH BY A SEWING MACHINE AND APPARATUS FOR THAT PURPOSE to be as follows:-
Year: 1884

page_text: I, JOSEPH BUCHANAN ROBERTSON of Lurgan in the county of Armagh, Ireland,
Engineer, do hereby declare the nature of my invention for "AN IMPROVED
METHOD OF EFFECTING HEM-STITCH BY A SEWING MACHINE AND APPARATUS FOR
THAT PURPOSE to be as follows:-
"
The compound stitch used for hemming handkerchiefs and other pieces of fabric
presents a series of holes through the fabric. In order to produce these holes,
various means have been employed. In some cases, threads are drawn out of the
fabric before stitching, but this involves time and trouble. In other cases, the
needle is bulged at its upper part and is made at one part of its cycle of movement
to descend so far that the bulge forces apart some threads of the fabric causing the
appearance of a hole, but the hole thus made is apt to be more or less closed by the
shifting of the threads when the next hole in order is made.
Now, according to my invention, I make the bulge of the needle of approximately
triangular section, so as to present an edge that cuts the thread of the fabric as
the bulge descends, and so makes a hole that is not closed by the formation of the
next hole. As it is of advantage to keep the stroke of the needle uniform, instead
of making the needle descend beyond its normal stroke to cut the hole, I make the
fabric rise while the needle is down. For this purpose, I pass the fabric between
a lower moveable plate and an upper presser foot which effects the feed, and, by
means of a cam suitably timed to the strokes of the needle, I cause the plate and
presser foot to rise together with the fabric held between them, while the needle is
down. When it is not desired to cut the thread of the fabric as above described,
the needle may have a bulge of the ordinary kind, and the fabric may be raised by
the plate and presser foot to have the hole pierced, so that variation of the stroke
of the needle for this purpose is thus avoided.
The cam or lever which causes the rise of the plate and presser foot may be so
arranged that it can, when desired, be thrown out of action, in which case the
stitching is carried on in the usual way.
M
ABEL & IMRAY,
Agents for the Applicant,
28, Southampton Buildings,
.London, W.C.

page_text: "
I, JOSEPH BUCHANAN ROBERTSON of Lurgan' in the County of Armagh, Ireland,
AN IMPROVED
Engineer, do hereby declare the nature of my invention for
METHOD OF EFFECTING HEM-STITCH BY A SEWING MACHINE AND APPARATUS FOR
"
THAT PURPOSE and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement, that is
to say-
The compound stitch used for hemming handkerchiefs and other pieces of fabric
presents a series of holes through the fabric. In order to produce these holes,
various means have been employed. In some cases, threads are drawn out of the
fabric before stitching, but this involves time and trouble. In other cases, the
needle is bulged at its upper part and is made at one part of its cycle of movement
to descend so far that the bulge forces apart some threads of the fabric, causing the
appearance of a hole, but the hole thus made is apt to be more or less closed by the
shifting of the threads when the next hole in order is made.
Now, according to my invention, I make the bulge of the needle of approximately
triangular section, so as to present an edge that cuts the thread of the fabric as the
bulge descends, and so makes a hole that is not closed by the formation of the
next hole. As it is of advantage to keep the stroke of the needle uniform, instead
of making the needle descend beyond its normal stroke to cut the hole, I make the
fabric rise while the needle is down. For this purpose, I pass the fabric between
a lower moveable plate and an upper presser foot which effects the feed, and, by
means of a cam suitably timed to the strokes of the needle, I cause the plate and
presser foot to rise together with the fabric held between them, while the needle is
down. When it is not desired to cut the thread of the fabric as above described,
the needle may have a bulge of the ordinary kind, and the fabric may be raised by
the plate and presser foot to have the hole pierced, so that variation of the stroke
of the needle for this purpose is thus avoided.
The cam or lever which causes the rise of the plate and presser foot may be so
arranged that it can when desired, be thrown out of action, in which case the
stitching is carried on in the usual way.
Fig. 1 of the accompanying drawings is a side view, Fig 2 is an end view and
Fig. 3 is a plan of so much of a hem stitch sewing machine as is necessary to
shew my invention applied thereto. Fig. 4 is a side view of the needle and Fig. 5
is a sectional plan to an enlarged scale on Z. In a bracket A projecting from the
underframe of the machine I mount a rocking spindle on which are fixed two arms.
The one arm B carries a roller which bears against a cam C fixed on the feed
spindle. The other arm D carries at its end a plate E which extends under the
presser foot F. On this plate and between it and the presser foot the fabric is held,
being fed forward step by step by the movement of the presser foot sliding it along
the plate E in the usual way. The needle N, has formed on it a sloping bulge at Z
taking a triangular form so as to present a cutting edge at one side. This cutting
part is so situated that when the needle is down in its lowest position it is just
above the fabric and consequently has no effect in cutting it. But when the
protuberances of the cam C, acting on B, cause the plate E to rise, the fabric is
raised along the needle up to the cutting part at Z, and thus one thread or several
threads of the fabric are cut so as to form the hole presented at each successive
hem stitch. The presser foot F, besides having its usual transverse joint to allow

page_text: for its canting a little longitudinally in its feeding movement, has also a
longitudinal joint pin J to allow for a little transverse canting in obedience to the
up and down movements of the plate E.
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. In effecting hem stitch, forming holes in the fabric by raising it while the
needle is down so as to subject threads of the fabric to the cutting action of an
edge formed on the upper part of the needle.
2. For the purpose of raising the fabric so that threads thereof are cut by the
edge on the needle, the combination with the double jointed presser foot, of the
plate E, and the arms D, B, and cam C whereby the plate is worked, substantially
as herein described.