IMPROVEMENTS IN LOOMS FOR WEAVING
Year: 1878

page_text: LETTERS PATENT to John Ainsworth, of Preston, in the County of Lancaster,
Cotton Mill Manager, for the Invention of "IMPROVEMENTS IN LOOMS FOR
WEAVING."
Sealed the 1st October 1878, and dated the 8th April 1878.
PROVISIONAL SPECIFICATION left by the said John Ainsworth at the Office
of the Commissioners of Patents on the 8th April 1878.
JOHN AINSWORTH, of Preston, in the County of Lancaster, Cotton Mill Manager.
"IMPROVEMENTS IN LOOMS FOR WEAVING."
This Invention has reference to the apparatus employed for lifting and lowering
the healds in the looms for weaving certain kinds of fancy goods known as the
"Willan and Mills" dobby, and consists in an improved construction of mechanism
of durable character, whereby the up-and-down movement of the knives is effected
in a more reliable manner than heretofore.
In the ordinary construction of the apparatus referred to the two knives move
in an up-and-down direction in vertical guide slots in the two side uprights of the
framing. Above the knives there is a rocking shaft having a pulley at each end.
A leather belt or strap passes over cach of the pulleys, and the depending extremities
of the straps are fastened to the outer ends of the two knives, so that when one of
the knives is being raised the other will be lowered.
The leather belts or straps are apt to stretch or give away, and are therefore un-
reliable, and, moreover, do not impart a steady motion to the knives; and it is
found that the latter alter their position as the straps give way, thereby causing
the "shed" to be irregular, and making bad work.
Now, according to my Invention, I dispenso with the straps, and employ a
separate rocking shaft mounted in suitable bearings to each knife, so that the two
knives may operate independently of each other.

page_text: The rocking shafts are in a position parallel to the knives, and from the two
extremities of the rocking shafts are arms which point inwardly. Attached to the
knives, one to each end, are links, the lower part being provided with a joint, the
upper ends hooking into notches formed in the upper side of the outer portion of
the arms, which project from each extremity of the two rocking shafts.
Motion is communicated to the rocking shafts through the medium of connecting
rods from the ordinary tappet shaft, which rotates a pair of cams or eccentrics so
arranged with regard to each other as that when one of the connecting rods is
moving upwards the other will be moving downwards.
The latter part of the arrangement is old, being the method usually employed for
actuating dobby knives; but, in order to obtain a smoother action by reducing the
vibration on the connecting rods, I place the treadles under the tappet shaft instead
of above it, as usually practised, and construct the cams or eccentrics with a
projecting flange upon the inner side of which the friction bowl of the treadle rests.
The two connecting rods are connected by joints at their upper ends to the two
arins projecting from the two rocking shafts at one side of the dobby, and the arms
are provided with slots, so that the upper extremities of the connecting rods may
be moved nearer or further from the centres of the two rocking shafts respectively for
the purpose of adjusting the amount of lift to be given to the knives.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Ainsworth in the Great Seal Patent Office on the 7th
October 1878.
John Ainsworth, of Preston, in the County of Lancaster, Cotton Mill Manager.
"IMPROVEMENTS IN LOOMS FOR WEAVING,"
This Invention has reference to apparatus employed for lifting and lowering the
hicalds in looms for weaving certain kinds of fancy goods, and more particularly to
the arrangement of mechanism' known as the Willan and Mills dobby, and consists
in an improved construction of incchanism for effecting the up-and-down movement
of the knives.
In apparatus, to which my Invention applies, as ordinarily constructed the two
knives move in an up-and-down direction in vertical guide slots in the two side
aprights of the framing. Above the knives there is a rocking shaft having a pulley
or disc at each end, and a leather belt or strap passes over each of the pulleys,
and the depending extremities of the straps are fastened to the outer ends of
the two knives, so that when one of the knives is being raised the other will
be lowered.
The leather belts or straps are apt to stretch or give way, and are therefore un-
reliable, and, moreover, do not impart a steady motion to the knives; and it is
found that the latter alter their positions as the straps give way, causing the shod
to be irregular, and making bad work.
Now, according to my Invention, I dispense with the straps, and employ a separate
rocking shaft mounted in suitable bearings to each knife, so that the two knives
may operate independently of each other.
In the accompanying Drawings Figs. 1 and 2 are side views, showing so much of
a dobby as is necessary to illustrate the application of any improved mechanism for
raising and lowering the knives.
In Fig. 1, a, a, are arms attached to the extremities of the rocking shafts b. Each
of the rocking shafts is provided with a pair of the arms a attached one at each
extremity; c, c, are guide openings within which the knives & move up and down
in the ordinary manner. Attached to the knives, one to each end, are links e jointed
at f, the upper ends hooking into notches y formed in the upper sides of the arms a.
Motion is communicated to the rocking shafts through connecting rods / from an
ordinary tappet shaft i, which rotates a pair of cams or eccentrics j, so arranged
with regard to each other as that when one of the connecting rods is moving
upwards the other will be moving downwards.
The latter part of the arrangement is old, being the method usually employed for
actuating dobby knives; but in order to obtain a smoother action by reducing the
vibration on the connecting rods, I place the treadles under the tappet shaft instead
of above it as usually practised, and construct the cams or eccentrics with a pro-
jecting flank k, upon the inner side of which the antifriction bowl of the treadle
rests (see Fig. 3).
The two connecting rods are connected by joints at their upper ends to the arms a
at one side of the dobby, and the arms have slots m, so that the upper extremities
of the connecting rods may be moved nearer to or further from the centres of the
two rocking shafts respectively to adjust the amount of lift to be given to the
knives.
In the arrangement shown in Fig. 2, the rocking shafts b are below the knives
instead of above them as in Fig. 1.
The outer ends of the arms a carry segmental portions of toothed wheels, and a
pinion n interposed between the two arms a produces the required reciprocating
motion of the two rocking shafts b, and the up-and-down movement of the
knives d.

page_text: By this arrangement only one connecting rod is necessary; it is (preferably)
actuated by a crank o attached to the outer end of the tappet shaft i. The upper
end of the rod is jointed to one extremity of a lever or arm p fastened at its
other extremity to one of the rocking shafts b.
The lever p may be formed in two portions connected as shewn, the arrangement
of slotted plates 9 providing means for adjusting the length of the lever p, and
consequently for altering the stroke of the arms a.
My Invention may obviously be applied to other modifications of dobby apparatus
in which an up-and-down reciprocal movement is required to be imparted to a pair
of knives.
Having described the nature of my said Invention, and the manner of performing
it, I desire it to bo understood that I do not intend to claim any of the mechanical
parts of the apparatus, herein-before described and shewn, when taken separately
and apart from the combination or application thereof in manner and for the pur-
poses herein described; but what I consider to be novel and original, and claim
as secured to me under the Letters Patent herein-before in part recited is, the con-
structing apparatus, substantially as bereiu-before described with reference to the
accompanying Drawings, for actuating the knives of dobbies as above set forth.
In witness whereof, I, the said John Ainsworth, have hereunto set my hand
and seal, this Fifth day of October, in the year of our Lord One thousand
eight hundred and seventy-eight.