IMPROVEMENTS IN POWER LOOMS FOR WEAVING
Year: 1877

page_text: LETTERS PATENT to Robert Barff Thomson, of Dundee, in the County of
Forfar, North Britain, Engineer, for the Invention of "IMPROVEMENTS IN
POWER LOOMS FOR WEAVING."
Sealed the 29th June 1877, and dated the 26th April 1877.
PROVISIONAL SPECIFICATION left by the said Robert Barff Thomson at the
Office of the Commissioners of Patents on the 26th April 1877.
ROBERT BARFF THOMSON, of Dundee, in the County of Forfar, North Britain,
Engineer. IMPROVEMENTS IN POWER LOOMS FOR WEAVING."
"
This Invention comprises improvements which are applicable wholly or in part to
various kinds of looms for weaving various materials, and which are of especial
advantage in comparatively large and heavy looms for weaving jute, hemp, or flax
fabrics.
The first part of the Invention relates to the warp beam, and consists in improved
arrangements for applying "drag" or tension to the warps. The beam is continued
of uniform diameter through its end discs, and has fixed on it outside of the end
discs grooved friction pulleys, by which the beam rests on friction blocks of wood
or other suitable material fixed on the gables or side frames. In the case of fabrics
requiring little drag these friction arrangements are sufficient, but when more drag
is required it is applied by means of friction blocks pressed upon the tops of the
beam pulleys by levers linked to lower levers on a rocking shaft, from which shaft,
herein-after termed the drag shaft, a lever extends towards the front of the loom,
where the necessary pressure can be conveniently applied and adjusted.
In some cases part of the drag is applied by a friction pulley and strap at the
front of the loom, on a fore-and-aft shaft geared to the beam by bevil wheels, and
used for taking back the warps when required.
In other cases when an extra tension is required the warps are led tortuously over
a pair of rods on a frame capable of being set angularly, so as to apply more or less
tension.
The beam may be of wood, or it may consist of a tube of cast iron or malleable
iron, and instead of having friction pulleys added outside the end discs, the friction

page_text: may be applied directly to the surface of the tubular beam. The drag shaft may
be used for conveniently centering the shedding treadles or levers on it, instead of
separate brackets being provided for these levers.
By combining the supporting and tensional appliances, as herein-before described,
space is economised and the gables or side frames can be placed nearer to each
other for a given width of fabric, so that the framing is rendered more rigid and
more compact. With the beam continued of uniform diameter through the end
discs and friction pulleys, as herein-before described, one beam may be adjusted for
different widths of loom by shifting the discs and pulleys at one end.
By the second part of the Invention the bearings in the gables for the crank
shaft journals are projected outwards, so as to form recesses on the inner sides to
admit the outer crank cheeks, or parts of them. With this arrangement the cranks
and the lathe swords can be put close to the inner faces of the gables, and the
shuttle box protector tongues can be placed against the centres of the swords, so
that the blow when knocking off acts in a direct plane through the centres of the
cranks, connecting rods, and swords, and thereby avoids the tortional action of
existing arrangements. The bearings for the low shaft are similarly projected
outwards, which, with vertical picking shafts mounted close outside of the gables
admits of the picking wipers being brought sufficiently close on the insides of the
gables.
These improvements also conduce, like those forming the first part of the Invention,
to the shortening of the distance between the gables for a given width of fabric, and
the consequent increased compactness and stiffness.
By the third part of the Invention bell-crank levers are fixed on a rocking shaft
to receive on their vertical arms the knocking-off stroke of the shuttle box protector
tongues, whilst their horizontal arms bear on volute springs, and the pressure of the
protector swell piece is taken off the shuttle just at the time of picking by means
of a trigger centered loosely on the protector rod, and which encountering a cam
guide or projection on the frame as the lathe moves back by means of a finger turns
the protector rod and makes it move back the swell piece, which for that purpose is
linked to the' lever on the rod. With this improvement the picking stroke will
require less force, and there will be less risk of the shuttle going astray.
By the fourth part of the Invention the shuttle is made with the front side lower
than the other, and the cops are compressed into a shape corresponding to that of
the shed, that is, so as to have the inner side deeper than the outer side. This
improvement will adınit of a smaller shed being formed, or of the shuttle carrying
a larger quantity of weft without risk of catching in the shed.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Robert Barff Thomson in the Great Seal Patent Office on the 24th
October 1877.
ROBERT BARFF THOMSON, of Dundee, in the County of Forfar, North Britain,
Engineer. "IMPROVEMENTS IN POWER LOOMS FOR WEAVING."
My said Invention comprises improvements which are applicable wholly or in
part to various kinds of power looms for weaving various materials, and which are
of especial advantage in comparatively large and heavy looms for weaving jute,
hemp, or flax fabrics.
The first part of my Invention relates to the warp beam, and consists partly in
improved arrangements for applying "drag" or tension to the warps, the main
feature of these arrangements being the carrying of the frame upon frictional
bearings.
By the second part of my Invention the bearings in the gables for the crank
shaft journals are projected outwards, so as to form recesses for the crank cheeks or

page_text: parts of them. The bearings for the low shaft are also similarly projected
outwards, which, with vertical picking shafts mounted close outside of the gables
admits of the picking wipers being brought sufficiently close on the insides of the
gables.
By the third part of my Invention bell-crank levers are fixed on a rocking shaft
to receive on their vertical arms the knocking-off stroke of the shuttle box protector
tongues, whilst their horizontal arms bear on volute springs, and the pressure of the
protector swell piece is taken cff the shuttle just at the time of picking by means
of a trigger and fixed cam guide.
By the fourth part of my Invention the shuttle is made with the front side lower
than the other, and the cops are compressed into a corresponding shape, so as to
admit of a smaller shed being formed, or of the shuttle carrying a larger quantity
of weft without risk of catching in the shed.
And in order that my said Invention and the manner of performing the same
may
be properly understood, I hereunto append a Sheet of explanatory Drawings to
be herein-after referred to, and representing my improved arrangements or con-
structions. In these Drawings the same reference numerals are used to mark the
same or like parts wherever they are repeated.
Figure 1 on the accompanying Sheet of Drawings is a vertical section of a loom,
as taken parallel to the gables or side frames, and Figure 2 is a horizontal section
of one gable and parts adjacent to it. The other Figures represent separate parts,
and are herein-after referred to. The warp'beam 6 is continued of uniform diameter
through its end flanges or discs 7 (of which discs one is shown in section in
Figure 2), and it rests on friction blocks 8 of wood or other suitable material fixed
in seats made for them at the back parts 9, and by preference in the planes of the
gables or side frames. In the case of fabrics requiring little drag these friction
arrangements are sufficient, but when more drag is required it is applied by means
of friction blocks 10 pressed on the tops of the beam by levers 11 connected by
links 12 to lower levers 13 on a rocking shaft 14, from which shaft, herein-after
termed the drag shaft, a lever 15 extends towards the front of the loom, where the
necessary pressure can be conveniently applied and adjusted.
In some cases the whole or part of the drag is applied by a friction pulley 16 and
strap 17 at the front of the loom on a fore-and-aft shaft 18 geared to the beam 0 by
bevil wheels 19, 20, and used for taking back the warps when required, for which
last-named purpose it has on it a spur wheel 21 having in gear with it a pinion 22
fixed to a hand wheel 23.
In other cases when an extra tension is required the warps 24 are led tortuously
over a pair of rods 25, 26, fixed to end frames 27 capable of being set angularly, so
as to apply more or less tension. The end frames 27 may be held in any desired
position, as shown in Figure 1, by means of a weighted pawl 28 engaging with a
ratchet-toothed sector 29 fixed on the framing; or they may be fixed by means of
a slot and screw bolt 30, as shown in Figure 4.
The beam 6 may be of wood (Figure 5), or it may consist of a tube of cast iron
or malleable iron. When the beam is of wood, iron friction pulleys 31 are fixed on
it, to rest on the friction blocks 8, and in the case also of the beam 6 consisting of
an iron tube, friction pulleys 31 may be fixed on it instead of its resting directly on
the friction blocks 8. The end discs or flanges 7 of the beam 6 are made each in a
single piece, instead of being in two halves bolted together, as usual.
The eye of
each disc or flange is made large enough to go on over the bevil wheel 20 and
friction pulley 31, and it is fixed in its place on the beam 6 by means of a pair of semi-
circular wedges 32 of wood or iron, and fitting the beam at their inner faces, whilst
being slightly conical externally, to admit of tightening in the disc or flange, the
eye of which is correspondingly coned. The drag shaft 14 may be used for con-
veniently centering the shedding treadles or levers 33 on it, instead of separate
brackets being provided for those levers.
By combining the supporting and tensional appliances as herein-before described,
space is economised, and the gables or side frames can be placed nearer to each other

page_text: for a given width of fabric, so that the framing is rendered more rigid and more
compact. With the beam 6, continued of uniform diameter through the end discs
and friction pulleys, as herein-before described, one beam may be adjusted for
different widths of loom by shifting the discs and pulleys at one end.
In accordance with the second part of my Invention, the bearing 34 (Figure 2),
in each gable or side frame for the journal 35, of the crank shaft 36, is projected
outwards so as to form a recess on the inner side to admit the outer crank cheek or
part of it in each case. With this arrangement the cranks 36, and the lathe swords
37, can be put close to the inner faces of the gables; and the shuttlebox protector
tongues 38 can be placed against the centres of the swords 37, so that the blow when
knocking off acts in a direct plane through the centres of the cranks 36, connecting
rods 39 and swords 37, and thereby avoid the tortional action of existing arrange-
ments. The bearings of the low shaft 40 are similarly projected outwards, which
with the vertical picking shafts 41 mounted close outside of the gables, admits
of the picking wipers 42 being brought sufficiently close on the insides of the
gables.
These improvements also conduce like those forming the first part of
my Invention
to the shortening of the distance between the gables for a given width of fabric, and
the consequent increased compactness and stiffness.
By the third part of my Invention, bell-crank levers 43, 44, are fixed on a rocking
shaft 45, to receive on their vertical arins 43, the knocking-off stroke of the shuttle-
box protector tongues 38, whilst their horizontal arms 44 bear on volute springs 46,
held on seats formed for them on the gable. The pressure of the protector swell
piece 47 is taken off the shuttle just at the time of picking by means of a trigger 48,
centered loosely on the protector rod 49, and which encountering a cam guide or
projection 50 on the gable as the lathe moves back, by means of a finger 51 acting
on the protector lever 38, 52, makes it move back the swell piece which for that
purpose is linked to the lever 52. With this improvement the picking stroke will
require less force, and there will be less risk of the shuttle going astray. When the
lathe moves forward, the trigger 48 does not act, but leaves the swell piece 47 free
to operate in the usual way when the shuttle gets home.
Figure 3 is a transverse vertical section (drawn full size on the accompanying
Drawing) of a shuttle made according to the fourth part of my Invention, that is,
with the front side lower than the back side. The cop for this shuttle is compressed
into a form corresponding to the cavity in the shuttle, as indicated in Figure 3.
Having thus particularly described my said Invention, and the manner of per-
forming the same, I have to state that I do not restrict myself to the precise details
herein described or delineated, but that what I believe to be novel and original, and
claim as the Invention secured to me by the herein-before in part recited Letters
Patent is,―
1. The applying of drag to the warp beam by making the beam rest with or
without pulleys on frictional blocks, combined when required with frictional blocks
pressed on the beam by levers, and if necessary, with other tension appliances,
substantially as herein-before described.
2. The making of the warp beam of uniform diameter through the end discs or
flanges, and when fitted with them through the pulleys, by which it rests on the
friction blocks or bearings, as herein-before described.
3. The making of each end disc or flange of the warp beam in a single piece
with a conical eye, to be fixed in position by conical wedges, as berein-before
described.
4. The centering of the shedding treadles or levers on the rocking shaft of the
warp drag apparatus, as herein-before described.
5. The forming of the bearings in the gables for the crank shaft and low shaft
to project outwards, and the arranging of the crank connecting rod, lathe sword,
protector tongue, and the lever of the knocking-off shaft on each side of the
loom, all in the same vertical plane, substantially as and for the purposes herein-
before described,

page_text: 6. The fixing of bell-crank levers on the knocking-off shaft to receive the
knocking-off stroke, and having their horizontal arms bearing on volute springs, as
herein-before described.
7. The relieving of the protector swell piece at the time of picking the shuttle
by means of a trigger acted on by a cam guide on the gable, as herein-before
described.
8. The shaping of the shuttle and the compressing of the cop in the manner
herein-before described with reference to Figure 3 of the accompanying Drawings.
In witness whereof, I, the said Robert Barff Thomson, have hereunto set
my hand and seal, this Twenty-third day of October, in the year of our Lord
One thousand eight hundred and seventy-seven.
Witness,
EDMUND HUNT,
Patent Agent,
Glasgow.
R. B. THOMSON. (LS.)