IMPROVEMENTS IN WEST FORKS FOR POWER LOOMS."
Year: 1852

page_text: LETTERS PATENT to William Stevenson, of Preston, in, the County
of Lancaster, Manager, for the Invention of "IMPROVEMENTS IN
WEST FORKS FOR POWER LOOMS."
PROVISIONAL SPECIFICATION left by the said William Stevenson
at the Office of the Commissioners of Patents, with his Petition,
the 15th October 1852.
r
I, WILLIAM STEVENSON, of Preston, in the County of Lancaster,
Manager, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN WEFT FORKS FOR POWER. LOOMS" to be as follows, that
is to say:
'the
The ordinary weft fork or protector, as commonly used for power
looms, for stopping. the loom action when the weft thread, breaks,.is
subject to very frequent breakage from the chance catching of the
shuttle against it. Now this Invention relates to the so forming
forks that when in danger from fracture from this cause the part of the
fork which is in danger. may give way. To effect this the vertical
portion of the fork is hinged or jointed to the body of the fork, so that

page_text: on coming in contact with the shuttle, in case of stoppage of the latter
in its transit across the loom, may be thrown up upon its hinge and
prevent the fork from breaking. After such action the hinged piece
falls down again to its proper working position, and the joint being
made with a stop on the opposite side of its centre, the motion of the
piece in the other direction is prevented, and the fork's action in
connection with the weft is unimpaired. A similar effect is also
obtainable by constructing. the vertical portion of the, fork of some
clastic material, which yields when struck against the shuttle, but is
stiff enough for the weft action.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Stevenson in the Great Seal Patent Office;
on the 2nd April 1853.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
WILLIAM STEVENSON, of Preston, in the County of Lancaster, Manager,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fifteenth day of October, One
thousand cight hundred and fifty-two, in the sixteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said William Stevenson, Her special licence that I, the said
William Stevenson, my executors, administrators, and assigns, or such
others as I, the said William Stevenson, my executors, administrators,
and assigns, should at any time agree with, and no others, from timé
to time and at all times thereafter during the term therein expressed,
should and lawfully might make, use, exercise, and vend, within the
United Kingdom of Great Britain and Ireland, the Channel Islands,
and Isle of Man, an Invention for "IMPROVEMENTS IN WEFT FORKS
FOR POWER LOOMS," upon the condition (amongst others) that I, the said
William Stevenson, by an instrument in writing under my hand and
seal, should particularly describe and ascertain the nature of the said
Invention, and in what manner the same was to be performed, and

page_text: cause the same to be filed in the Great Seal Patent Office within six
calendar months next and immediately after the date of the said
Letters Patent.
"
:
NOW KNOW YE, that I, the said William Stevenson, do hereby
leclare the nature of my said Invention, and in what manner the same
to be performed, to be particularly described and ascertained in and by
the following statement, reference being had to the Drawing hereunto
attached, and to the letters and figures marked thereon (that is to say):
Whereas the ordinary weft fork or protector, as commonly used for
power looms, for stopping the loom action when the weft thread breaks,
is subject to very frequent breakage from the chance catching of the
shuttle against it. Now my Invention relates to the so forming the
forks that when in danger of fracture from this cause the part of the
fork which is in danger may give way. To effect this the vertical
portion of the fork, or that part whereon the weft thread acts, is hinged
or jointed to the body of the fork, so that on coming in contact with the
shuttle, in case of stoppage of the latter in its transit across the loom,
such picce may be thrown up upon its hinge, and thus prevent the fork
from breaking. After such action the hinged piece falls down again to
its proper working position, and the joint being made with a stop on
the opposite side of its centre, the motion of the piece in the other
direction is prevented, and the fork's action in connexion with the
working of the weft is unimpaired. Figure 1, on my Sheet of Drawings
is a side or longitudinal elevation of one form of my improved weft
fork or protector as in working action; Figure 2, is a plan of the
same corresponding; Figure 3, is a side view of one of the weft prongs
detached; and Figure 4, is a similar view of the back stop or detent
lever which actuates the stop rod of the loom whenever the weft
breaks. The fixed stud or holding stay A, of the fork is cast or
otherwise formed with a wide double eye B, for the reception of the
flat expanded end of the detent lever C, which is retained in position
by a rivet joint pin passing through the lugs B, of the double eye, and
through the lever. The latter is thus well guided laterally, whilst
the expandled portion B, affords room for the reception of the hinged-
prongs D, for the actual weft action. These prongs are, as usual, three

page_text: in number. They are loosely entered into three corresponding slots in
the piece C, and the single joint pin, already referred to, secures then
on their centre of oscillation. The bottom of each of the recesses or
slots in the piece C, is angularly sloped, as at E, in Figure 4, whilst
the inserted end of each of the prongs is correspondingly angled or
inclined to fit it. The result of this arrangement is, that so long as
the fork works in its regular routine of duty its prongs hold the
position assigned to them by the sharp lines in Figures 1, and 2, on
my Sheet of Drawings, and the passing weft thread acts upon their
vertical portions so as to elevate the catch F, of the detent lever clear
of the stop movement at each passage, just as would occur with the
ordinary fork, because the incline upon the prongs acts upon the
inclined bottom of its recess exactly in the same manner as would arise
if the fork were a solid one. But, on the other hand, if an intercepted
shuttle chances to be in the way it simply acts upon the inside edges
of the prongs D, and clevates them on their joint centre to the position
delineated by the dotted lines. Thus the prongs give way, and their
fracture, which is inevitable with the common solid fork, is avoided."
Then so soon as the obstacle is removed the prongs fall to their accus-
tomed position, and their regular action goes on. 'A similar effect is
also obtainable by constructing the vertical or prong portion of the fork
of some clastic material, which yields' when struck against the shuttle,
but is stiff or rigid enough for the weft action.
"
Having now described and particularly ascertained the nature of my
Invention, and the manner in which the same 'is or may be used or
carried into effect, I may observe, in conclusion, that I do not confine
or restrict myself to the precise details or arrangements which I have
had occasion to describe or refer to, as many variations may be made
therefrom without deviating from the principles or main features of my
Invention; but what I consider to be novel and original, and therefore
claim as the Invention secured to me by the herein-before in part recited
Letters Patent, is,―
First, the systems or modes of constructing and arranging the weft
forks or protectors of power looms for the prevention of fracture and
derangement, as herein-before described.
.
E

page_text: Second, the application and use of weft forks or protectors with
hinged or jointed prongs for the purpose herein-before described.
In witness whereof, I, the said William Stevenson, have
hereunto set my hand and scal, this Twenty-ninth day of
March, in the year of our Lord One thousand eight hundred
and fifty-three.
WILLIAM STEVENSON. (L.S.)