IMPROVEMENTS IN OVER-EDGE SEWING MACHINES
Year: 1885

page_text: CAROLTIVATION.
I, EDMUND HUNT, of 87 St Vincent Street, Glasgow, in the County of Lanark,
North Britain, Patent Agent, do hereby declare the nature of my said invention
for IMPROVEMENTS IN OVER-EDGE SEWING MACHINES" 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 :-
My said Invention relates to over-edge sewing machines, of the kind described
in Laing's Patent Specification No 3493 of 1874 and in my own Patent
Specification N° 2856 of 1878 and the object of my present Invention is to
improve and simplify the construction of such nachines and to reduce their cost.
In a machine of the kind referred to a helical needle passes completely through
the material that is being sewn and is not fixed to any other part; whilst the yarn
or thread passes repeatedly round what is termed a thread barrel in combination
with which there is mechanism for regulating the tension or the greater or less
tightness of the sewing. My present Invention deals with three important parts
of the machine, namely, the needle with its driving mechanism, the thread barrel,
and the tension mechanism.
The needle is in the form of a conical helix or helicone but is placed with its
smaller and larger convolutions reversed as compared with the arrangement
described in my Specification No.2856 of 1878, and it is driven by a single conical
grooved wheel or pulley on a shaft at right angles to the thread barrel, whilst it is
supported and guided by internal and external antifriction rollers. The thread
barrel is made of such reduced. size as to be a mere tube and is driven by a belt
applied directly to it. The tension mechanism comprises a peculiarly shaped tail
connected to the end of the thread barrel or tube but not turning therewith, the
loops of thread passing between such tail and a frictional shield which is pressed
against it more or less according to the degree of tension desired.
My improvements are shown on two accompanying sheets of explanatory
drawings, figure, 3, on sheet, 1, being a front elevation of the machine, with parts
supposed to be broken away to reduce the length, and figure, 5, on sheet, 2, being
a sectional plan corresponding to figure, 3, whilst the other figures represent
separate details. In these drawings the same reference numerals are used to mark
the same or like parts wherever they are repeated.
The machine shown in figure, 3, is mounted on a table or stand (not shown) in
the lower part of which the first-motion shaft, 10, is carried, this shaft having on
t fast-and-loose pulleys for a driving belt, and also a pulley, 11, a belt from which
D

page_text: drives a pulley, 12, on a transverse horizontal main shaft, 13, carried in suitable
bearings on the framing of the machine. By a pair of bevil wheels, 14, the
shaft,, 13, drives a worm, 15, gearing with a worm wheel, 16, on the feed shaft, 17,
which, as in the earlier machines by means of a lantern or sprocket wheel, 18,
drives an endless feed chain, 19, partly indicated by dotted lines. The feed
chain, 19, carries the edges of- the sacking or other material which is to be sewn
along towards the right hand, over the long front plate, 20, of the machine and
under a long narrow presser plate, 21, which as in the earlier machines is pressed
down by curved arms, 22, 23, held by springs in boxes, 24, 25, fixed to the
framing.
The main shaft, 13, has fast on it a conical pulley, 26, made with a round rim, 27,
to serve also as a hand wheel; and the front conical surface of the pulley has spiral
or helicone grooves (indicated by shade lines in figure, 3,) formed in it to engage
with the convolutions of the helicone needle, 28, shown separately in figure, 4. This
helicone needle, 28, which is by preference square in section is placed with its
axis, horizontal and so that the front parts of its convolutions where they cut the
horizontal plane of its axis are in the line of sewing or parallel to the front
plate, 20, of the machine. The needle is internally supported by three conical
antifriction rollers, 29, arranged as will be best understood from figure, 8, which is
a projection by lines parallel to the axis of the needle; and a similar conical
roller, 30, is applied outside of the needle as a guide in front of it and a little above
. its middle. The three inner rollere, 29, which are also shown in figure, 1, are
carried on spindles fixed in bosses formed in a casting, 31, which fits in a socket
formed for it in a casting, 32, in which is made the front bearing of the main
shaft, 31, and also a long bearing for the thread barrel or tube, 33. The casting, 31,
which may be called the needle carrier is secured in its socket by a pin, 34, and is
withdrawn from its socket when the needle has to be inserted or removed. The
outer guide roller, 30, is carried by a horn formed on the casting, 32. A cover or
cap, 35, of a segmental spherical form and shown separately in figures, 6, and, 7, is
fixed to the outer ends of the spindles carrying the internal antifriction rollers, 29,
to prevent the thread from catching on those rollers and this cover is made with a
conical flange or rim projecting inwards from its edge to guide and support the tail
end of the needle.
The needle, 28, is gripped between one of the internal antifriction rollers, 29, and
the conical pulley, 26, the convolutions of the needle engaging in the grooves of the
pulley; and owing to the arrangement and proportions of the parts the pulley
practically acts on portions of the, needle extending appreciably above and below
the horizontal plane passing through the axes of the pulley and needle.
The thread tube, 36, is held in the long bearing hereinbefore mentioned as formed'
in the casting, 32. A rod or bar, 37, which does not turn, extends through its axis
and has fixed to the left-hand end of it a head, 38, fitted with a grooved pulley, 39.
A cord, 40, having one end fixed to a lug, 41, on the casting, 32, passes round this
pulley, 39, and thence to and round a guide pulley, 42, and down to a weight,
which weight by means of the cord and pulleys applies a pressure tending to move
the thread tube, 36, towards the right hand. The right-hand end of the rod or
bar, 37, has fixed to it a tail, 43, of a form which is best seen in figure, 5, the
cross-sections of it at various parts being circular or nearly 80. The thread
tube, 36, passes through the needle, 28, and through a slot cut for it in the
cap, 35, and, as with the earlier inachines, the first action when a length of sewing
is being done, is to form a succession of loops which passing through the sacking or
other material and round the tube are retained on the latter, and travel along it
towards the right hand until the first of them reaches the end of it. Then as the
sacking or other material continues to be carried towards the right hand by the
feed chain, the loops successively pass off the end of the tube; and the tension of
the thread or greater or less tightness of the sewing depends on the manner in
which the loops pass off from the tube. The tail, 43, has bearing on the inner side
of it from the point backwards, a curved frictional shield, 44; between which and

page_text: the tail each successive loop has to pass; and the tension is regulated by making
the shield bear with more or less pressure towards the left hand. The shield, 44, is
fixed on a slide, 45, fitted to move on a fixed guide bar, 46, and drawn towards the
left hand by a cord, 47, passing round a guide pulley, 48, to a weight which is of
course less than the weight hereinbefore referred to as applied for moving the thread
tube towards the right hand. By the action of the successive loops on the tail, 43,
the thread tube is gradually moved towards the left hand.
The thread tube, 36, is driven by a belt, 49, from a pulley on the first-motion
sbaft, 10, below, this belt being applied directly to the tube in the manner best
seen in figure, 2. Next below the tube there is a roller, 50, having journals which
are in guide slots in a pair of brackets and below the roller, 50, there is a flanged
pulley, 51, having its journals in the same guide slots but borne up by bearings
which are adjustable by screws. The driving belt, 49, passes in contact with the
flanged pulley, 51, the flanges preventing the end-on movement of the thread tube
from moving the belt from its proper position, and the flanged pulley drives the
intermediate roller, 50, which is thus made to support the thread tube against the
driving strain and at the same time to assist in driving it.
The two plies of sacking or material the edges of which are to be sewn together
with the over-edge helical stitches produced by the machine have their right-hand
ends entered under the left-hand end of the presser plate, 21, whilst their edges
are made to project inwards beyond the inner edge of the presser plate sufficiently
for the sewing action. In figure, 3, a portion of the presser plate, 21, is supposed
to be broken off in order to show a guide, 52, along which the inner edges of the
sacking move. This guide, 52, is made of thin sheet steel, the right-hand end of
it projecting through the convolutions of the needle at which part its top and
bottom edges are curled or bended over, as shown in figure, 8, (in which the dotted
line, 53, corresponds to the horizontal plane) in order to support and guide the
edges of the plies and keep them in close contact with each other. The part of
the guide, 52, from near the needle to its left-hand end has only its upper edge
curled or bended over, the edges of the plies being there supported by the inner
edge of the front plate, 20.
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-The combination of the helicone needle having its pointed end on its smallest
convolution, with the parts for holding and driving it, all arranged and operating
substantially as herein before described.
2-The improved arrangement of the thread barrel or tube and of the parts for
driving it, substantially as herein before described.
3-The arrangement of the cord and pulleys by which pressure is applied to
the thread tube tending to move it towards the right-hand substantially as herein-
before described and shown in the accompanying drawings.
4-The combination of parts forming the tension mechanism, and consisting of
the frictional shield, the peculiarly-shaped tail of the thread tube and the
appliances for pressing those parts together all arranged and operating substantially
as herein before described.