IMPROVEMENTS IN LAING'S OVERHEAD SEWING MACHINE
Year: 1876

page_text: LETTERS PATENT to William Martin, the younger, Director, David Russell
Dawson, Secretary, both of Laing's Patent Overhead Hand-stitch Sewing
Machine Company, Limited, and Robert Orchar, Engineer, all of Dundee, in
the County of Forfar, North Britain, for the Invention of "IMPROVEMENTS IN
LAING'S OVERHEAD SEWING MACHINE"
Sealed the 14th July 1876, and dated the 6th May 1876.
PROVISIONAL SPECIFICATION left by the said William Martin, David Russell
Dawson, and Robert Orchar at the Office of the Commissioners of Patents on
the 6th May 1870.
WILLIAM MARTIN, the younger, Director, DAVID RUSSELL DAWSON, Secretary,
both of Laing's Patent Overhead Hand-stitch Sewing Machine Company, Limited,
and ROBERT ORCHAR, Engineer, all of Dundee, in the County of Forfar, North
Britain. "IMPROVEMENTS IN LAING'S OVERHEAD SEWING MACHINE."
This Invention relates to improvements in some of the details of that sowing
inachino for which Letters Patent were granted to James Laing, dated the
Twelfth day of October, One thousand eight hundred and seventy-four, and
numbered 3493.
The first improvement has for its object to avoid or diminish the wear and
tear of the screw by which the thread barrel is moved into and out of the tube or
cylinder which contains it.
This object is effected by substituting for the screw a camb, whose contour is
approximately that of an involute curve, and having a deep step. This camb is
rotated by gearing driven from any convenient part of the machine, and its curved
surface bears preferably upon a square tumbler carried on a stud in a lever con-
nected to the thread barrel. As the camb rotates it by pushing back the lever
draws the thread barrel inwards or backwards until the tip of the curved surface
of the camb passes the tumbler, at which instant the deep step of the camb permits
the lever and thread barrel to be again forced out by the falling of a weight
attached to the lever, and which weight is lifted by the action of the camb in
Price Gdl

page_text: drawing back the lever. Change cambs are provided with surfaces varying in
extent of travel according to the work required to be sewn.
In place of the camb a sliding wedge or inclined surface may be used, which as
it is moved acts upon the lever and draws it back, thereby lifting the weight,
until sliding out of contact with the lever it affords a sudden release thereto, so
that the lever is drawn back by the falling weight and the thread barrel again
forced out.
Under these two preceding arrangements the screw for operating the thread
barrel is dispensed with, but the screw may be retained by attaching the cord by
which the weight is lifted, or spring extended to the tube or cylinder which
contains the thread barrel or to any revolving part of the machine, so that the
weight is lifted or spring extended independently of the action of the screw.
The
screw is thereby relieved of the duty of lifting the weight or extending a spring,
and that wear and tear thereof due to the constant stress and friction caused by
the weight or spring always forcing the screw-thread against the catch which enters
it prevented. With this arrangement of lifting the weight independently of the
screw a trigger is provided by which the weight is allowed to fall at the
instant the thread barrel has completed its stroke, so that it is again rapidly
forced out.
The second improvement consists in carrying the tube or cylinder within which
the thread barrel moves in a solid cylindrical bearing, thereby avoiding the anti-
friction rollers hitherto used.
The third improvement consists in providing a fixed inner guide for the needle
in place of the inner guide roller hitherto used.
The fourth improvement consists in placing the axis of the driving cones for
the variable motion in the same plane as the axis of the cylinder and thread
barrel.
The fifth improvement relates to the presser by which the bags or other articles
being sewn are held down on the table and pitch chain. This consists in carrying
the presser in spring brackets attached to a bar placed at a height above and
parallel to the length of the machine. To this bar the presser and brackets are
attached by moveable joints, so that when it is desired to move the presser out of
contact with the articles being sewn all that is necessary is for the attendant to
move the presser and spring brackets round upon the bar. The springs in the
brackets force the presser down on the cloth with the requisite stress.
The sixth improvement has for its object to provide for a finer adjustment for
the rate of travel of the pitch chain than is obtainable with the change spur wheels
and pinions bitherto employed. This is effected by substituting friction wheels and
pinions for the spur gearing, and by introducing a friction clutch on the shaft that
drives the pitch chain by which the width of the stitches is regulated, as well as
the tension on the spiral needle, that tension being thereby prevented from reaching
an extent which would be dangerous to the needle by virtue of the friction clutch
slipping before that degree of tension is reached.
The seventh improvement relates to dispensing with the reverse cone pullies,
and employing friction plates rotating in opposite directions for driving a friction
roller between thein on a shaft at right angles to the shafts of the friction plates,
and so that by moving the friction roller inwards or outwards from the axis of the
friction plates the requisite variable motion is obtained.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Martin, David Russell Dawson, and Robert Orchar in the
Great Seal Patent Office on the 6th November 1876.
WILLIAM MARTIN, the younger, Director, DAVID RUSSELL DAWSON, Secretary,
both of Laing's Patent Overhead Hand-stitch Sewing Machine Company, Limited,
and ROBERT ORCHAR, Engineer, all of Dundee, in the County of Forfar, North
Britain. "IMPROVEMENTS IN LAING'S OVERHEAD SEWING MACHINE."
Our said Invention relates to improvements in some of the details of that sewing
machine for which Letters Patent were granted to James Laing, dated the Twelfth
day of October, One thousand eight hundred and seventy-four, and numbered 3493.
The first improvement has for its object to avoid the wear and tear of the
screw by which the thread barrel is moved into and out of the tube or cylinder
containing it.
The second improvement consists in carrying the tube or cylinder within which
the thread barrel moves in a solid cylindrical bearing, thereby avoiding the antifric-
tion rollers hitherto used.
The third improvement consists in providing a fixed inner guide for the needle in
place of the inner guide roller hitherto employed.
The fourth improvement consists in placing the axis of the front driving cone
for the variable motion in the same plane as the axis of the cylinder and thread
barrel.
The fifth improvement relates to the presser by which the article being sewn is
held down on the table and pitch chain; and
A sixth improvement has for its object to provide for a finer adjustment in the
rate of travel of the pitch chain than is obtainable by the means employed in the
machine as originally constructed.
And in order that the overhead sewing machine as constructed with these
improvements may be properly understood, we now proceed more particularly to
set forth the system, mode, or inanner in or under which our said improvements
are or may be used or carried into practical effect, reference being had to the
accompanying Sheet of Drawings and to the letters and figures marked thereon,
that is to say :-
On the Sheet of Drawings hereunto appended, Figure 1 is a front elevation.
Figure 2 an elevation of the end marked X, Figure 1, and Figure 3 a plan of the
overhead sewing machine herein-before referred to, with the improvements con-
stituting our said Invention shewn in conjunction therewith. As shewn by these
Figures, the improved machine consists of a rectangular framework A, supporting at
its rearward side a shaft B, which is rotated by a belt passed round the pulley C of
the fast and loose pulleys C, D, situate on one end of the shaft. Another pulley F
is also fixed on the shaft B, and from it motion is communicated by the band E to
a cylindrical spiral hook or needle a round which the band E passes, and which is
similar in construction to the spiral hook or needle of the overhead sewing machine
described in the aforesaid Specification of the said James Laing, it being pointed at
the end which first pierces the cloth or fabric, and at its opposite end formed with a
hooked eye by which the thread used in sewing is held. The band E passes from
the pulley F round two other pulleys G in the direction shewn at Figure 2 of
the Drawings, and it is stented by a roller H carried in a lever 1 centred on the
lower part of the framing A and weighted at I' in the manner shewn. A spur
wheel J is fixed on the shaft B and geared with a corresponding pinion K on the
axis of the drawing cone L, on which a pulley M² is also secured, and by a belt or
band passed round the said pulley M², the thread barrel N of the machine and the
tube M containing it are rotated.
An improvement, forming part of our said Invention, consists in supporting the
said tube i at the end thereof marked M¹ in a solid cylindrical bearing M' male in
the framing of the machine, thereby avoiding the antifriction rollers employed to

page_text: support the corresponding end of the tube M in the machine as shewn and described
in the aforesaid Specification of the said James Laing.
Another improvement consists in dispensing with the inner roller employed to
guide the needle in the machine as described in the aforesaid Specification of the
said James Laing, and providing instead thereof a fixed inner guide O, seen in
detail at Figure 4, which surrounds the thread barrel tube M, and is secured to
the front centre gable or standard M* of the framing A. By this means lateral
motion of the needle is prevented.
At
From the driving cone L rotatory motion is communicated by the belt or band
P to the front driving cone Q, the shaft or spindle whereof carries a clutch box b,
into which a clutch c, sliding on a feather on its shaft, is geared whilst the needle
is sewing and disengaged when it is required to supply thread to the needle.
the back of the clutch a box or chamber, containing a spiral spring e, is formed,
and on the extremity of the spindle of the clutch ca tangent screw d is secured
and geared with a worm wheel e', fixed on a shaft g, lying at right angles to the
axis of the cone Q. On the shaft g a double camb R, the contour of each section of
which is approximately that of an involute curve having a deep step, is also fixed.
The curved surface of the camb bears whilst the needle is sewing upon a pin or tumbler
I carried in a slot made in the lever S, which is centred at its lower end on a bracket
or footstep T, and formed at its upper extremity with a toothed quadrant, which
gears into a horizontal rack formed at U, Figure 3, in a saddle V connected to the
spindle of the thread barrel N, and to a spindle or rod i, which passes through
the bearings of the cone Q and of the tangent screw d, as seen at Figure 3. On
this spindle or rod the thread drag or tension and the knife l, by which the end
of the thread is severed from the cloth or fabric being sewn as in the machine
described in the aforesaid Specification of the said James Laing, are carried. The
saddle V is further connected to a rod or spindle m, at one end of which a disc or
striker n is fixed, and in connexion with the said striker an apparatus consisting of
a lever o, connecting rod or link p, cranks q, r, and lever 8, are provided.
cranks q and are situate respectively at the upper and lower extremities of a
vertical rod u, carried in a bracket attached to the framing A, whilst the lever a is
centred on a separate rod or pin t, also carried in the bracket. One end of the
lever s is connected to the crank by a pin v, which passes downwards through n
slot in it, whilst the opposite end of the said lever 8 is attached to the clutch c, as
seen in plan at Figure 3 of the Drawings. The threader w, by which the bight or
loop of thread is delivered to the needle, as in the machine described in the
aforesaid Specification of the said James Laing, is situate on and projects towards
the needle from the axis of the horizontal lever o.
Weights X are attached to the quadrant lever S as shown.
The
The operation of this apparatus which is employed instead of the screw actuating
the thread barrel N as described in the aforesaid Specification of the said James Laing,
is as follows: Whilst the needle is sewing with a thread previously supplied to it the
clutches b and c are in gear with each other, whereby rotary motion is communicated
to the camb R through the intervention of the tangent screw & and worm wheel el.
This motion of the camb R, which is in the direction of the arrow, Figure 1, forces the
lever S backwards, which lever being geared by the rack formed on the saddle V
with the spindle V of the thread barrel N also draws the said barrel backwards
into its tube M as the thread becomes unwound therefrom, in the manner described
in the aforesaid Specification of the said James Laing. This backward motion
continues until all the thread has been unwound from the barrel N, at which time
the part 3 of the camb is bearing against the pin or tumbler. The part 3 having
passed the pin or tumbler the barrel N is again pushed out to its full extent by the
weights X, drawing forward the lever S, and the clutches b and c are on the said
forward motion thrown out of gear with each other by the striker n acting against
the pin v.
The attendant then removes a new piece of thread from the hook +,
places a loop of it over the part of the threader, and by means of the lever O

page_text: presents the loop to the eye or hook of the needle at the same time engaging the
clutches b and c, which has the effect of again setting in uiotion the camb R, and
the new piece of thread having been wound on the barrel N, as set forth in the
aforesaid Specification of the said James Laing, the sewing is proceeded with. The
engaging and disengaging of the clutches c and 6 may be described as follows:-
The crank g has an inclined slot formed in its boss through which a pin screwed
into the spindle u passes. Thus when the lever O is actuated so as to present. the
thread to the needlo the spindle is forced upwards and the pin is thereby brought
above the level of the striker n. The lever S being now set free, the spring c
acting on the back of the clutch c forces the said clutch into gear with the
clutch b, and the sewing is continued until the barrel N has been moved back
to the extremity of its rearward stroke, from which it is again brought forward by
means of the weights X, as already described.
The cambs R employed vary in extent of travel according to the work requiring
to be sewn; and in place of the camb a sliding wedge or inclined surface may be
used, which as it is moved acts upon the lever S and draws it back, thereby lifting
the weight until sliding out of contact with the lever it affords a sudden release
thereto so that the lever is drawn forwards by the falling of the weights and the
thread barrel N is again forced out.
The driving cone Q for the variable motion is as seen on the Drawings placed
in the same plane as the axis of the tube M of the thread barrel N instead of
being placed in a higher plane, as illustrated on the Drawings annexed to the
aforesaid Specification of the said James Laing, and this arrangement permits of a
bar or rod being placed along the front of the machine to carry the improved
presser 6, by which the fabric being sewn is held down on the table and pitch
feeding chain of the machine. The improvement in the presser consists in carrying
it in brackets 7, at whose interiors coil springs are placed, the said brackets being
attached to the bar 8 laid parallel to tho length of the machine, so that when it is
desired to move the presser out of contact with the fabric being sewn all that is
necessary, is for the attendant to lift the presser. The springs in the brackets 7
force the presser down on the cloth with the requisite stress.
In this machine a finer adjustment of the rate of travel of the pitch chain 9 is
obtained than in the machine described in the aforesaid Specification of the said
James Laing by the addition of friction discs 10 and 11 to the spur gearing 12,
and by introducing a friction clutch 13 on the shaft 14 that drives the pitch chain
by which the width of the stitches is regulated as well as the tension on the spiral
needle, such tension being thereby prevented from attaining an extent which
would be dangerous to the needle by virtue of the friction clutch slipping before
that degree of tension is reached. The clutch consists of the plate or disc 13
secured on the shaft 14 and through which screws 16 are passed, these. bearing
against the loose friction disc 10 so as to force it into contact with the wheel 12
and the said wheel into contact with the fixed friction disc 11.
Another improvement embraced by this Invention, and which is not shewn on
the Drawings, consists in dispensing with the reversed cone pulleys L and Q, and
employing friction plates rotating in opposite directions for driving a friction
roller between them on a shaft at right angles to the shafts of the friction plates,
and so that by moving the friction roller inwards or outwards from the axis of
the friction plates the requisite variable motion is obtained.
Having now described and particularly ascertained the nature of our said
Invention, and the system, mode, or manner in or under which the same is or may
be used or practically carried into effect, we would observe in conclusion that
what we consider to be novel and original and therefore claim as the Invention
secured to us by the herein-before in part recited Letters Patent is―
First. The improved Laing's overhead sewing machino constructed substan-
tially as herein-before described and shewn on tho appended Sheet of Drawings."
Second. The camb R, lever S, with tumbler and other apparatus in connexion
therewith, for effecting the outward and inward movement of the thread barrel

page_text: N and for threading the needle, substantially as herein-before described with
reference to the Sheet of Drawings hereunto annexed.
Third. The sliding wedge arrangement herein-before described for effecting the
outward and inward movement of the thread barrel.
Fourth. The fixed inner guide O for the spiral needle.
Fifth. Placing the axis of motion of the driving cone Q in the same plane as
the axis of motion of the thread barrel N, as and for the purpose herein-before
set forth with reference to the accompanying Drawings.
Sixth. The improved presser 6 arranged and constructed as herein-before
described and shewn on the Drawings hereunto annexed.
Seventh. The friction gearing for driving the pitch feeding chain 9 and the
friction clutch for preventing an undue strain on the needle, substantially as
herein-before described with reference to the apparatus marked 10, 11, 13, and 16,
on the accompanying Drawings.
In witness whereof, I, the said David Russell Dawson, on behalf of myself
and the said William Martin, tho younger, and Robert Orchar, have hereunto
set my hand and seal, this Second day of November, One thousand eight
hundred and seventy-six.
D. R. DAWSON. (LS.)