AN IMPROVEMENT CONNECTED WITH DOBBIES OR JACQUARDS OF LOOMS FOR OPERATING THE HEALDS
Year: 1885

page_text: COMPLETE SPECIFICATION.
I, JAMES HOLLINGWORTH, Managing Director of the firm of Hutchinson,
Hollingworth and Company, Limited of Dobcross, Yorkshire Power. Loom Makers
do hereby declare the nature of my invention for "AN IMPROVEMENT CONNECTED
WITH DOBBIES OR JACQUARDS OF LOOMS FOR OPERATING THE HEALDS" and in
what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :—
My invention has reference to that description of dobby employed in the loom
called "Knowles American Loom."
In this loom the healds are raised and lowered by means of jack levers or boll-
crank levers such levers being operated backward and forward by means of certain
toothed discs called vibrating wheels, the said jack levers being attached to the
discs by means of a connecting rod.
In order that my improvements and the object thereof may be better understood
I herein give reference to the accompanying sheets of drawings wherein Fig 1
represents the mechanism and their relative positions as at present employed
for operating the healds. A is the jack or bell-crank lever working upon a
stud B and connected by bar C to the vibrating wheel D which is caused to
oscillate upon its stud first in one direction and then in the other by means of the
rotary top and bottom cylinder gear E and F which in their rotary motion catch
into one of the vibrator wheels and turn it around part of a revolution, or the
length of the slot G which is formed in each wheel.
The position of the parts as shewn in Fig 1 indicates that at the next rotary
movement of the top cylinder gear E it will catch into the teeth of the vibrator
wheel and cause it to oscillate in the direction of the arrow a in doing which the
fulcrum b of the connector bar C will be transferred to the opposite side as shewn
in Fig 2 whereby the healds will have been raised, but on the rotary movement
of the bottom cylinder gear F the teeth thereof will catch into the teeth of the
vibrator wheel and oscillate it in the opposite direction whereby the healds will be
lowered.
When weaving light goods the various operations and movements thus described
are satisfactorily performed, but when heavy goods are being woven great tension
is placed upon the healds and the levers, so much so, that when the vibrator wheel
has been oscillated as shewn in Fig 1, that the tension of the healds is so great as
to pull the jack lever forward in the direction of the arrow H and cause the
vibrating wheel to run back again whereby the shed would not be opened,
consequently the weaving would be stopped.

page_text: After much thought to find the cause of this and to provide a remedy, I have
discovered that the vibrator wheel ran back, because the centres b and c of the
connector bar C where almost in a direct line as shewn by dotted lines, so that
when the healds were pulling at the bottom arm of the jack lever A that the
thrust from centre c to contre b was such as to cause the vibrating wheel to return,
whereby the shed would not be formed.
The same defect, applys when the parts are reversed as shewn in Fig 2.
To prevent the evils complained of I have discovered that if the centre c is
taken further away laterally, from the stud B that instead of the centre c being
horizontally opposite the centre b, that such centre c would be thrown up as seen
in Fig 3, consequently any effort to cause the vibrator wheel to run back would
fail, as the line of thrust is now helping to lock the vibrator wheels and to hold
them permanently fast until oscillated by the top cylinder gear.
It will therefore be seen that by increasing the distance laterally of the centres c
and B that the centre c will be thrown above or below the centre b, so that any
attempt of the vibrator wheel to return would be prevented by the line of thrust
of the connector C.
Although I have referred in this specification to the line of thrust, and to the
overturning. of the vibrator wheel by the tension of the healds upon the lower arm
of the bell-crank lever, as shewn in Figs 1 and 3, it must be understood that the
improvements apply to the opposite movement, where a pull instead of a thrust
would come into operation as would be the case when the parts were in the
position shewn in Figs 2 and 4. Instead of the centre c being moved nearer the
vibrating wheel D as explained, the said centre c may remain where it is, and the
centre B be removed further backward which would effect the same result; in
cither case the centre c is in such relation to centre b as to be so far above, and so
far below as to prevent the vibrator wheel from running back as explained.
As the top cylinder gear E is a barrel extending the full width of the series of
vibrator wheels 1), and as the front end of the connector C has to pass underneath
the barrel E when traversing backward and forward around the vibrator wheel D
the said connector C had to be made very narrow at the bend fas seen in Fig³ 1
and 2 which made it weak and unable to bear the strain put upon it, but by
altering the position of the centres according to my Invention, the bend can be
made broador, therefore stronger, as the upper part of the said bend does not get
so near the underside of the gear F as it did when the centres were stationed as
formerly.
Having now shewn and described my Invention and explained its object, and
the manner of putting the same into practice I here remark that I make no claim
to the exact distance the centre c shall be above or below the centre b to overcome
the evils complained of, but what I believe to be new and therefore claim as my
Invention is
The arrangement of centres bc and B in such manner as to place the centre c so
far above, or so far below the centre b as will prevent the vibrating wheel D
running back,