Improvements in Let-off Motions of Looms for Weaving.
Year: 1892

page_text: Date of Application, 16th Mar., 1892
Complete Specification Left, 14th Dec., 1892-Accepted, 14th Jan., 1893
PROVISIONAL SPECIFICATION.
Improvements in Let-off Motions of Looms for Weaving.
I, THOMAS HARGREAVES BRIGG, of Thornton Road, Bradford, Yorkshire,
Manufacturer, do hereby declare the nature of the said invention to be as
follows:-
This invention relates to certain improvements in or applicable to the let-off
motion of looms for weaving, the improvements being designed to effect a more
even let-off of the warps, in consequence of which a more even piece or fabric will
be produced.
The improvements have special reference to that class of let-off mechanism
wherein each end of the warp-beam is fitted with a surrounding metallic hoop
which is mounted in a curved bracket bolted to the adjacent end of the back of the
loom-frame, resting on diagonally faced supporting shoes which are removably
fitted to a part of the bracket extending below the warp-beam, and being borne on
by a top cap which is fitted loosely in a recess made in the underside of an upper
lever which is caused to exert the desired pressure by the following devices:-The
lever engages with a hook cast on a part of the bracket rising above the level of
the warp-beam, projects from such connection over the warp-beam, and engages at
its overhanging end with a vertically depending link. The lower end of the link
hooks under the nose of a hanging lever pivoted on a stud cast on the projecting
end of the part of the bracket extending below the warp-beam. To the lower end
of the hanging lever of the device at one end of the warp-beam, there is pivoted a
bell-crank lever which is weighted and connected by a rod to a bell-crank lever
pivoted to the lower end of the device at the other end of the warp-beam, the latter
bell-crank lever being formed with a handle-part, which is linked to an upper part
of its hanging lever when the apparatus is in operation, and is unlinked from said
lever when the warp-beam is required to be "pulled back."
To permit of the warp-beam being "pulled back" without releasing the devices
controlling the let-off, I fit each end of the warp-beam with three concentric hoops.
The innermost hoop is tongued and fitted to the beam-end in a usual manner, and
is provided with one or more screw-nuts the heads of which project and act as keys
engaging with slots or keyways formed in the middle hoop, which fits closely
around the innermost hoop and at all times acts therewith. One end of the middle
hoop is formed with a ring of ratchet teeth, which engage with one or more pawls
pivoted within a circumscribing part of the outermost hoop, the other part of which
latter snugly fits around the middle hoop, the arrangement being such that when
the warp is pulling on the warp-beam, all three hoops at each end co-act as one,
the devices controlling the let-off operating on the outermost hoop, the pawl and
ratchet connections of which with the middle hoop permit of the warp-beam
(together with the two inner hoops at each end) being "pulled back without
affecting the exterior hoop, which can thus at all times remain engaged by the said
controlling devices.
In lieu of each said upper lever of the let-off mechanism, I use two independent
upper levers arranged side by side and respectively connected (as hereinafter
described) to the said rising part of the bracket, such levers project therefrom over
the adjacent end of the warp-beam, and, at their overhanging ends, are downwardly
curved and hooked or formed with through eyes and adjustably connected to a
vertically depending link the lower end of which engages in an adjustable manner
with the upper end of an adjustable hanging lever, as further referred to
hereinafter.
To the underface of each said upper lever I, in one modification, apply a loosely

page_text: I
fitting widely extending cap the underface of which is adapted to bear only by its
end parts, which are diagonally faced, on the hooped end of the warp-beam, and to
said upward extension of the bracket I apply an adjustable stop-piece fitted with
lock-nuts, in such a position as that each cap will be caused to butt against its
stop-piece at each "pick," which will materially assist in the production of an even
let off. To secure a sensitive balance and freedom of movement of such caps,
centre each thereof in a hardened conical recess made in the underface on its upper
lever, by means of a hardened steel conical point formed with a shank which is
driven into the top of the cap. Or, I pivotally connect each such cap to its upper
lever. When using such caps, I connect the upper levers to said upper extension
of the bracket, by making V-shaped recesses in the upper face of the lever adapted
to engage with downwardly directed hardened steel knife-edges fitted to the said
upward extension of the bracket.
Or, in lieu of such widely extending caps, I pivotally attach to the underside of
each upper lever, two independent diagonally faced caps adapted to swivel about
their connections and accommodate themselves to the surface of the hooped end of
the warp-beam. I space these caps of each upper lever apart (in a direction at
right angles to the axis of the warp-beam), and arrange the caps of the adjacent
upper levers out of alignment, (in a direction parallel with said axis), and so obtain
an extended bearing area adapted to minimise the effects of any inequalities in the
surface of the hooped end of the warp-beam with which such parts engage. When
using such caps, I connect the upper levers to said upper extension of the bracket
by means of a link adapted with an adjustable hook-like centre and with a
set-nut.
The outer ends of each pair of upper levers are connected to the upper end of
said vertically depending link by screw-threading the latter, adapting it with a
set-nut and passing it through a cross-piece which bears on the end parts or in the
through eyes of said levers, at parts thereof which are formed with knife-edges.
By the aforesaid knife-edged and like adjustments, I attain a very sensitive
co-operation of the co-acting parts of the device, which ensures the rise and fall
of the weighted levers at each "pick," and enables me to use a heavy weight for
light fabrics.
In order to facilitate the adjustment of the let-off devices for weaving light or
heavy fabrics, I form each of said hanging levers with a double nose, forming two
hook-like parts at different distances from the centre upon which the lever is
pivoted, and in order to retain the vertical dependency of the said link connecting
Baid upper levers to said hanging lever, I make the centre upon which said hanging
lever is pivoted adjustable, by casting it excentrically in relation to the length of
a carrying part which can be bolted to said under projecting part of the bracket,
either end inwards of a recess formed therein, so as to adjust the centre of the
hanging lever correspondingly to the alteration of the connection thereto of said
vertically depending link. By the alteration of leverage thus obtained, the same
weights are made to serve, whether light or heavy fabrics are being woven.
When applying the improvements to let-off mechanism wherein the hooped ends
of the warp-beam are encircled by ropes connected to independent weighted levers
pivoted one to each loom-end and fitted with weights which require to be lifted in
order to allow of the warp-beam being "pulled back," I dispense with such ropes,
and in lieu of each thereof I apply one of said curved brackets with its bottom and
top frictional attachments.
At the overhanging ends of said upper levers I pivot a grooved pulley, and also
pivot a like pulley on a stud projecting from said lower projecting part of the
bracket, and I apply the required frictional resistance by means of a chain or other
suitable flexible connection which is passed from the short arm of a handled bell-
crank lever (one of which is pivoted to each said weighted lever) over the upper
pulley, under the lower pulley, and upwards to the underside of said upper levers,
to which or to a descending part of the chain between the top and bottom pulleys
the end of the chain is connected. With such device, the let-off mechanism is put

page_text: in operation by raising the bell-crank levers so as to cause the weighted levers to
raise the weights from off the floor, and is removed by lowering said bell-crank
levers so as to cause said weighted levers to lower the weights on to the floor.
But, as aforesaid, in any let-off' mechanism, the necessity of taking off the weights
5 for enabling the warp-beam to be "pulled back," can be avoided by adapting the
ends of the warp-beam with concentric hoops as herein before firstly described.
Dated this 15th day of March 1892.
DAY, DAVIES & HUNT,
321, High Holborn, London, W.C., Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Let-off Motions of Looms for Weaving.
I, THOMAS HARGREAVES BRIGG, of Thornton Road, Bradford, Yorkshire,
Manufacturer, do hereby declare the nature of the said invention, and in what manner
the same is to be performed, to be particularly described and ascertained in and by
the following statement :—
This invention relates to certain improvements in or applicable to let-off motions
of looms for weaving, the improvements being designed to effect a more even let-off
of the warps, and to cause the production of a more even piece or fabric.
66
The improvements have special reference to that class of let-off mechanism
wherein each end of the warp-beam 12, (fitted with a surrounding metallic hoop 13,)
is mounted in a bracket 14, bolted at 15, to the adjacent end of the back of the
loom-frame 16, the warp-beam end resting on diagonally-faced supporting shoes 17,
(fitting loosely in recesses made in a part of the bracket extending below the
warp beam,) and being borne on by a top-cap" fitting loosely in a recess made in
the underside of an
upper lever," which latter is caused to exert the desired
pressure by the following devices; The lever engages with a hook cast on a part
of the bracket rising above the level of the warp-beam, projects from such
connection over the warp-beam, and engages, (at its overhanging end,) with a
vertically depending link. The lower end of the link hooks under the nose of a
"hanging lever" pivoted on a stud cast on the projecting end of the part of the
bracket extending below the warp-beam. To the lower end of the "hanging lever"
of the let-off device at one end of the warp-beam is pivoted a bell-crank lever 61,
which is weighted and connected by a rod 62, to a bell-crank lever 63, pivoted to
the lower end of the let-off device at the other end of the warp beam, the latter
bell-crank lever being formed with a handle part which is linked as at 64, to an
upper part of its hanging lever " when the apparatus is in operation and is
unlinked from said lever when the warp-beam is required to be "pulled back."
The present improvements relate to those parts of the device aforesaid, through
which the weighted levers 61, 63, are operative in applying the required frictional
resistance to the hooped ends of the warp-beam.
The improved apparatus is illustrated on the accompanying drawings, on which―
Fig. 1, is an end elevation.
Figs. 2 and 3, are plan views respectively of the parts above and below the
line a, b, Fig. 1.
Fig. 4, is a back elevation of Fig. 1.
Fig. 5, is a partial view representing some of the parts illustrated in Fig. 4, in
different positions.
Fig. 6, is an end elevation of a modification.
Fig. 7, is a plan view, partly in section, of Fig. 6.
Fig. 8, is a back elevation of another modification.
Fig. 9, is a plan view of part of the device represented in Fig. 8.
Fig. 10, is an end elevation of the warp-beam; and,-
Fig. 11, is a sectional elevation thereof,

page_text: On the drawings, like reference numerals indicate like parts wherever they are
repeated.
Referring, firstly, to Figs. 1 to 5,-The improved let-off motion illustrated in
these figures, is made with two independent " upper levers" 18, each of which is
fitted on its upper side with a hardened steel recessed bearing piece 19, adapted to
engage with a hardened steel knife-edged bearing piece 20, which is fitted to an over-
hanging part of an upward extension of the bracket 14, and acts as fulcrum to the
lever. Each lever 18, is also fitted on its under side with a hardened steel conically-
recessed bearing piece 21, adapted to rest on and apply the desired pressure to a
hardened steel conical bearing piece 22, fitted in the upper side of a widely
extending "top-cap" 23, the under face of which is arched so as to be adapted to bear
only by its end parts 24, (which are diagonally-faced, ride Fig. 2,) on the hooped
end of the warp-beam. The upward extension of the bracket 14, is provided with
two adjustable screw-stops 25, (provided with lock nuts 26,) in such positions as
that each cap 23, will be caused to butt against its stop 25, at each "pick." The
overhanging ends of the levers 18, are distended (ride Fig. 2,) and are each fitted
in alignment with the longitudinal centre of the lever with a hardened steel
recessed bearing piece 27. Both of such bearing pieces 27, are borne-on by
hardened steel knife-edged bearing pieces 28, fitted to the underside of a cross
piece 29, through a central aperture in which a vertically depending link 30, is
suspended in an adjustable manner, the projecting end of the link being screw-
threaded and fitted with a set-nut 31.
Or, in lieu of such widely extending caps 23, there may be pivotally attached to
the underside of such lever 18, (vide Figs. 6 and 7,) two independent diagonally-
faced caps 32, each of which is adapted to swivel about its pivotal connection 33,
and to accommodate itself to the surface of the hooped end of the warp-beam.
The caps 32, of each lever are spaced apart, and those of the adjacent levers are
arranged out of alignment (vide Fig. 7,) by which means there is obtained an
extended and distributed bearing area well adapted to minimise the effects of any
inequalities in the surface of the hooped end of the warp-beam. When using such
independent caps 32, each lever is fulcrummed in a depending book-like part 34,
extending from a carrier 35, the elevation of which can be adjusted by a set-nut 36,
engaging with a screw-threaded link 37, pivoted at 38, to the bracket 14.
By the aforesaid knife-edged, pivoted and like adjustments of the co-acting parts,
a very sensitive co-operation thereof is attained, which ensures the rise and fall of
the weight-applying levers at each "pick."
In order to facilitate the adjustment of the aforesaid let-off devices for weaving
light or heavy fabrics, each of the said "hanging levers" 39, is formed with a
double nose 40, forming two hook-like parts 41, at different distances from the
centre or stud 42, upon which the lever is pivoted; and with either of which hook-
like parts the lower hooped end of the link 30, may be engaged, vide Figs. 4 and 5,
the former representing the adjustment suitable for weaving heavy goods, and the
latter the adjustment suitable for light goods. In order to retain the vertical
dependency of the link 30, from said levers 18, in each of such adjustments, the
stud 42, is made adjustable in relation to the bracket 14, to an extent corresponding
to the difference of the distances of the hook-like parts 41, of the lever, from its
said centre. This adjustment is effected by casting the stud 42, excentrically in
relation to the length of a carrying part 43, which can be bolted, as at 44, to said
under projecting part of the bracket 14, with either of its ends inwards of a
recess 45, made in such bracket, ride Figs. 4 and 5.
When applying the improved let-off mechanism (in lieu of the usual ropes
encircling the hooped ends of the warp-beam,) to looms fitted with independent
levers 46, (one to each loom end) fitted with weights 47, which require to be lifted
to allow of the warp-beam being pulled back," the over-hanging ends of the
levers 18, are connected with such levers 46, in the following manner, vide Figs. 8
and 9.
At said end of the levers 18, is secured a cross-piece 48, provided with a stud 49,

page_text: on which is mounted a grooved pulley 50; a like pulley 51, is mounted on a fixed
stud 42*, projecting from said under extension of the bracket, and on each lever 46,
is mounted a sleeve 52, to which a handled lever 53, is pivoted. One end of a
wire-rope, chain or other suitable flexible connection 54, is connected to the short
arm of the lever 53, and the connection is passed from thence over the pulley 50,
under the pulley 51, and is continued upwards and connected at its other end to the
underside of the cross-piece 48. When so applied, the let-off mechanism is put in
operation by raising the lever 53, to the position indicated, in which it is retained
by any suitable catch 65, and is released, to allow of the warp beam being "pulled
back" by lowering the lever 53, so as to cause the weights 47, to rest on the floor.
To permit of the warp beam being "pulled back" without releasing the devices
controlling the let-off, (whatever be the means employed for controlling the let-off ;)
I fit each end of the warp-beam (vide Figs. 10 and 11,) with three concentric
hoops 13, 55 and 56. The innermost hoop 13, is tongued and fitted to the beam
end in a usual manner, and is provided with one or more screw-nuts 57, the heads
of which project and act as keys engaging with slots or keyways 58, formed in the
middle hoop 55, which fits closely around the innermost hoop and at all times acts
therewith. One end of the middle hoop is formed with a ring of ratchet teeth 59,
which engages with one or more spring pawls 60, pivoted within a circumscribing
part of the outermost hoop, the other part of which latter snugly fits around the
middle hoop; the arrangement being such that when the warp is pulling on the
warp-beam all three hoops at each end co-act as one, the device controlling
the let-off operating on the outermost hoop the pawl and ratchet connection of
which with the middle hoop, permit of the warp-beam (together with the two inner
hoops at each end) being "pulled back" without affecting the exterior hoop, which
can thus at all times remain engaged by the said controlling devices.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. The application to let-off mechanism (of the class hereinbefore referred to) of
looms for weaving, of the several improvements hereinbefore described with
reference to Figs. 1 to 5, of the accompanying drawings.
2. The application to such mechanism of the improvements hereinbefore
described with reference to Figs. 6 and 7, of the drawings.
3. The modification of such mechanism as hereinbefore described with reference
to Figs. 8 and 9, of the drawings, when applied to looms fitted as described with
reference to such figures.
4. The application to the warp-beams of looms for weaving of the improvements
hereinbefore described with reference to Figs. 10 and 11, of the drawings.
Dated this 12th day of December 1892
DAY, DAVIES & HUNT,
321, High Holborn, London, W.C., Agents for the Applicant.