Improvements in Sewing Machines.
Year: 1891

page_text: Date of Application, 24th July, 1891
Complete Specification Left, 11th Apr., 1892-Accepted, 14th May, 1592
PROVISIONAL SPECIFICATION.
Improvements in Sewing Machines.
I WILLIAM BIRCH of Milton Street Iron Works Lower Broughton Manchester
in the County of Lancaster, Engineer, do hereby declare the nature of this invention
to be as follows:-
This invention relates to improvements applicable to that class of sewing
machines employed by bleachers, calico printers, and others, for the purpose of
sewing together the ends of pieces of woven fabric, and known as
"Birch's rotary
sewing machines," wherein the cloth feed consists of a revolving ring of metal
provided with a series of pins or needle points which enter the cloth and feed it
along as the sewing proceeds.
In machines of this class it has been usual either to form the edge of the feed-
ring into a ratchet wheel and to give an intermittent forward motion to the same
by means of a reciprocating catch or dog working into the ratchet teeth, or the
feed ring was made plain and was propelled by means of a notched clip embracing
the edge thereof.
The first was costly and also objectionable ou account of the difficulty of
regulating the length of the stitch which could not be varied less than one tooth at
a time, and the objection to the second was that both the ring and the notched clip
were liable to wear and in that case the feeding became uncertain.
According to my present improvements I drill holes through about the centre
of the "feed-ring" all round its circumference and at a suitable distance apart
(say about three eighths of an inch) and I provide a corresponding stud wheel, the
studs or pins of which take into the said holes at the inside of the ring.
stud wheel is keyed upon a short shaft which is carried in suitable bearings fixed
to, or cast with, the feed ring carrier.
This
Upon this stud wheel shaft I also key a ratchet wheel which is provided with a
driving ratchet or dog, and also a holding ratchet.
The driving ratchet is jointed to a lever swinging on the said short shaft and
carrying an adjustable bowl which works in a slot at the lower end of a slotted
lever.
This lever rocks on the centre of the feed-ring carrier and at its upper end it is
jointed to a link at the other end of which is a ring embracing an excentric
mounted on the lower cam or tappet shaft of the machine.
As this shaft revolves the excentric causes the lever to rock and by means of
the ratchet and wheel and stud wheel before named to give an intermittent revolving
motion to the feed-ring. The length of stitch is regulated by raising or lowering
the position of the adjustable bowl in the slot of the rocking lever.
As a modification 1 propose sometimes to dispense with the rocking lever by
providing the ratchet lever with a slotted arm projecting horizontally or nearly so,
and by curving and lengthening the excentric rod or link and jointing its lower
end to a pin adjustable in the slot of the ratchet lever arm, so that the excentric
acts direct (through its link or rod) on the ratchet lever, and the length of stitch
is more easily adjustable as the pin is more accessible in this arrangement thau in
that previously described.
Dated this 23rd day of July 1801

page_text: COMPLETE SPECIFICATION.
Improvements in Sewing Machines.
I WILLIAM BIRCH of Milton Street Iron Works Lower Broughton Manchester
in the County of Lancaster, Eugincer, 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 improvements applicable to that class of sewing
machines employed by bleachers, calico printers, and others for the purpose of
sewing together the ends of pieces of woven fabric, wherein the cloth feed consists
of a revolving ring of metal provided with a series of pins or needle points which
enter the cloth and feed it along as the sewing proceeds.
In machines of this class it has been usual either to form the edge of the feed-
ring into a ratchet wheel and to give an intermittent forward motion to the same
by means of a reciprocating catch or dog working into the ratchet teeth, or the
feed-ring was made plain and was propelled by means of a notched clip embracing
the edge thereof.
The first was costly and also objectionable on account of the difficulty of
regulating the length of the stitch, which could not be varied less than one tooth
at a time, and the objection to the second was that both the ring and the notched
clip were liable to wear, and in that case the feeding became uncertain.
My improvements are intended to remedy these defects.
The nature of my invention and the manner in which the same is to be carried
into practical effect will be readily understood on reference to the two sheets of
drawings hereunto annexed and the following explanation thereof.
On Sheet 1 of the drawings Fig. 1 is a front elevation and Fig. 2 a side view of
so much of a sewing machine of the class above referred to as is necessary to
illustrate my invention.
On Sheet 2 of the drawings Figs. 3 and 4 are detached views of parts of the
same hereinafter more particularly referred to.
a is the needle bar, 6 the presser-foot, and c the feed ring provided with pins or
points d.
"
According to my present invention I drill holes e through about the centre of 3
the "feed-ring call round its circumference and at a suitable distance apart (say
about three eighths of an inch) and I provide a corresponding stud wheel the
studs or pins of which take into the said holes at the inside of the ring. This
stud wheel is keyed upon a short shaft g which is carried in suitable bearings
fixed to, or cast with, the feed ring carrier h.
Upon this stud wheel shaft g I also key a ratchet wheel which is provided with
a driving ratchet or dog k, and also a holding ratchet l.
g
The driving ratchet is jointed to a lever m swinging on the said short shaft
and carrying an adjustable bowl or pin n which works in a slot at the lower end of
a slotted lever o.
This lever o rocks on the centre 7 of the feed-ring carrier / and at its upper
end it is jointed to a link p at the other end of which is a ring p' embracing an
excentric q mounted on the lower cam or tappet shaft r of the machine.
4
As this shaft r revolves the excentric y causes the lever o to rock, and by means
of the ratchet k and wheel i and stud wheelf before named, to give an intermittent 4
revolving motion to the feed-ring c. The length of stitch is regulated by raising
or lowering the position of the adjustable bowl or pin n in the slot of the rocking
lever o.
Я
As a modification I propose sometimes to dispense with the rocking lever o by
providing the ratchet lever with a slotted arm projecting horizontally or nearly 5
so (see detached view Fig. 3) and by curving and lengthening the excentric rod or
P, and jointing its lower end to the pin t, adjustable in the slot of the ratchet
link

page_text: lever arm s, so that the excentric q acts direct through its link or rod p on the
ratchet lever m, and the length of stitch is more easily adjustable as the pint is
more accessible in this arrangement than in that previously described.
The holding dog or ratchet prevents the feed wheel from turning backwards
and in order to prevent it from over running in a forward direction I make an
annular recess in the face of the stud wheelf (see also detached section Fig. 4)
which I line with leather or other suitable substance and inside this recess I place
a split ring u of metal which can be expanded or contracted by a screw bolt
passing through lugs at the ends of the ring, which latter is prevented from
revolving by lugs to projecting one on each side of the part of the feed-ring
carrier which supports the stud wheel shaft
g.
The expanding ring u acts as a brake aud prevents the feed ring from over-
running and I would here remark that other forms of brake may be used for the
same purpose if preferred.
Having now particularly described and ascertained the nature of my said inver-
tion and in what manner the same is to be performed I declare that what I
claim is :-
The means substantially as hereinbefore described and illustrated by the drawings
annexed for actuating the feed-ring in sewing machines of the class above
referred to.
GEO. DAVIES & SON,
4, St. Ann's Square, Manchester, Agents for the Applicant.