IMPROVEMENTS IN SCREW WRENCHES
Year: 1861

page_text: LETTERS PATENT to William Thomas Weston, of 4, Trafalgar Square,
(Patent Office,) in the County of Middlesex, for the Invention of
"IMPROVEMENTS IN SCREW WRENCHES."
Sealed the 16th April 1862, and dated the 17th October 1861.
PROVISIONAL SPECIFICATION left by the said William Thomas Weston
at the Office of the Commissioners of Patents, with his Petition, on the
17th October 1861.
I, WILLIAM THOMAS WESTON, of 4, Trafalgar Square, (Patent Office,) in
the County of Middlesex, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN SCREW WRENCHES," to be as follows:-
The Invention consists in forming on either side of the handle of a screw
wrench containing one fixed jaw or chop thereof a toothed rack, the situation
of which is at that part of the handle of the wrench along which the moveable
jaw or chop is to slide, and in furnishing such moveable jaw with an eccentric
thread or helical worm of a screw formed on a disc or button furnished with a
milled edge, and placed with its pivot perpendicularly with regard to the rack
into which it works, so that by turning such screw or thread by means of its

page_text: milled edge the moveable jaw is caused to move along the rack as may be
desired with respect to the fixed jaw of the wrench.
Although I prefer to form the rack on the inner edge of the handle of the
wrench, I propose to form it on the outer edge or that opposite to the jaw of
the wrench when it is desirable to do so; and I propose to do this whatever
may be the form of the handle, whether straight, as is ordinarily the case, or
curved inwards or outwards to any extent, and of any size, in order to suit
particular purposes; and when the handle is curved the biting surface of the
jaws when closed are not parallel to each other, for it will be obvious that the
space or difference between the parallels of the fixed and moveable jaws of the
wrench, when the same are closed, must be equal to the versed sine of the arc
of the circle described by the moveable jaw along the rack. When the rack
is on the outer edge of the handle the eccentric thread or screw worm must
be situated accordingly, so as to derive and communicate motion to the
moveable jaw from the rack.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Thomas Weston in the Great Seal Patent Office
on the 17th April 1862.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
THOMAS WESTON, of 4, Trafalgar Square, (Patent Office,) in the County of
Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventeenth day of October, in the year of our Lord
One thousand eight hundred and sixty-one, in the twenty-fifth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said William Thomas Weston, Her special licence that I, the said William
Thomas Weston, my executors, administrators, and assigns, or such others
as I, the said William Thomas Weston, my executors, administrators,. and
assigns, should at any time agree with, and no others, from time 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 SCREW WRENCHES," upon the condition
(amongst others) that I, the said William Thomas Weston, my executors or
administrators, by an instrument in writing under my, or their, or one of

page_text: their hands and seals, should particularly describe and ascertain the nature
of the said Invention, and in what manner the same was to be performed,
and 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 Thomas Weston, do hereby
declare the nature of my said Invention, and in what manner the same is
to be performed, to be particularly described and ascertained in and by the
following statement:-
My Invention consists in forming on either side of the handle of a screw
wrench containing one fixed jaw or chop thereof a toothed rack, the situation
of which is at that part of the handle of the wrench along which the moveable
jaw or chop is to slide, and in furnishing such moveable jaw with an excentric
thread or helical worm formed on a disc or button having a milled edge, the
disc being perforated with holes similar to a windlass or capstan, and placed
with its pivot perpendicularly with regard to the rack into which it works, so
that by turning such screw or thread by means of its milled edge, or by the
application of a lever to the holes, the moveable jaw is caused to move along
the rack as may be desired with respect to the fixed jaw of the wrench.
Although I prefer to form the rack on the inner edge of the handle of the
wrench, I propose to form it on the outer edge, or that opposite to the jaw of
the wrench, when it is desirable to do so, and I propose to do this whatever
may be the form of the handle, whether straight, as is ordinarily the case, or
curved inwards or outwards to any extent, and of any size, in order to suit
particular purposes; and when the handle is curved the biting surface of the
jaws when closed are not parallel to each other, for it will be obvious that the
space or difference between the parallels of the fixed and moveable jaws of the
wrench, when the same are closed, must be equal to the versed sine of the arc
of the circle described by the moveable jaw along the rack. When the rack
is on the outer edge of the handle the excentric thread or worm must
be situated accordingly, so as to derive and communicate motion to the
moveable jaw from the rack.
•
In order that my Invention may be more fully understood, I will now
proceed to explain the best means I am acquainted with for carrying the same
into effect, reference being had to the illustrative Sheet of Drawings hereto
annexed, and the numeral figures and letters of reference marked thereon, in
which Fig. 1 represents a perspective view of the wrench, the handle of which
is of a curved form.

page_text: a is the handle, having the fixed jaw b thereon; c is the moveable jaw
containing a slot in which the milled edge, disc, or button d is turned on the
pin e; and f, f, are holes in the disc to receive a lever.
It will be seen that the handle is furnished with a series of crescent-formed
teeth, forming the rack f, upon which the helical worm or excentric thread
on the disc operates in order to close or separate the jaws.
Fig. 2 represents another perspective view of the wrench, in which a modi-
fication of the moveable jaw is shewn, the object of which is to enable the disc
and excentric thread or worm to become speedily disengaged or released from
its gear with the rack, in order that the moveable jaw may be drawn open or
separated from the fixed jaw without the necessity of turning the disc, as is
necessary in the former example. I make that party of the moveable jaw
which forms the under edge of the slot in which the pine is placed in a
separate piece from the sliding and biting portions, and join it thereto by a
hinge or pin, as shewn at h, a groove being cut in g to receive a tongue
extending from the back of the jaw.
The Drawing shews this new arrangement of parts at the time when the
worm is out of gear with the rack, and it will be seen that there is no
impediment whatever to the free sliding of the jaw along the handle inde-
pendently of the rack. When it is desired to bring the parts into gear the
hinged portion is closed, and a spring catch or fastening at i will maintain its
position; or a spring may be so arranged at the back of the hinge as to
constantly tend to close the same. It is obvious that many plans might be
devised of accomplishing this object, but it would be unnecessary to detail
them, as their adoption would not affect the principle of my Invention.
Another application of this Invention may be made by reducing or almost
entirely dispensing with the handle of the wrench; in such case, by furnishing
the moveable jaw with a groove, pulley, or roller working in a slot on a stud
or pin, power may be obtained and applied by my screw wrench rack for
various useful purposes.
Fig. 3 is another view of a wrench, contrived so as to effect the same object
as Fig. 2.
It will be seen that the part g is not detached from the jaw, as in Fig. 2,
but that it is so modified in form as to permit the button and worm to be
taken out of gear from the rack by means of the hinged tongue g', into which
the pin e is inserted. The part 9 has a slot cut through it, in which the
tongue g' may be lowered or raised. The tongue may be retained in position
by any suitable fastening, or a flat spring, shewn in dotted.lines at h, may act

page_text: upon the hinge, and tend to keep the worm and rack in gear. Another
method I adopt is to enlarge the slot running through the sliding portion of
the moveable jaw, as shewn by the dotted lines i, i, Fig. 3. A spring is to be
inserted and fixed to the jaw so as to act upon the handle of the wrench, and
tend to keep them apart, thus maintaining the gearing of the rack and worm
until it is desired to release the same, which may readily be accomplished by
the mere application of pressure to the jaw, whereby it will be pressed against
the handle of the wrench, and the change of its position will remove the
worm from gear with the rack. In some cases I furnish screw wrenches on
those portions thereof along which the jaw travels with a projection on each
side, as shewn at Fig. 1, k, either in the form of a segment of a circle, or of a
wedge of very obtuse angle, or of any other desired form, and I groove out the
interior of the sliding surfaces of the jaw to correspond with the shape of the
projection. The object of this improvement is to afford a firm auxiliary
bearing surface for the jaw when powerful pressure is applied thereto, with
the view of relieving the gearing parts from excessive strain, and also to
strengthen the wrench when a large nut is being turned. The projections may
be continued the entire length of the handles, if desired.
Fig. 4 shews a transverse vertical section of the wrench handle, having a
segmental projection on each side thereof. When the wrench is thus improved
the moveable jaw should not quite touch or bear upon the usual surfaces of the
handle, but upon these segmental projections, so that when excessive force is
applied to the wrench the segments will create, as it were, a tendency in the
grooved sides of the jaw to bulge outwards, and cause a firm self-grip between
the jaw and projections, which is still further increased in proportion to the
force applied to the wrench; thus by this improvement the rack and worm are
greatly relieved from strain. This improvement is alike applicable to all
species of screw cramps, or to all apparatus wherein a moveable jaw is made
to slide along a standard or bar, and to be adjusted at any part thereof, and
sustain pressure. The segmental projections on the sides of the bar and
corresponding grooves in the jaw are very advantageous improvements upon
the present system of rectangular or flush surfaces of these parts.
<:
Having now described and ascertained the nature of my said Invention of
Improvements in Screw Wrenches," and the manner in which the same is
to be performed, I would remark, in conclusion, that I do not restrict myself
to the exact or precise detail or configuration of parts herein expressed and
shewn, as the same may readily be varied or modified without in any way
departing from the main principles of my Invention; but what I claim as my

page_text: .
Invention, and desire to be secured to me by the herein in part recited Letters
Patent, are, the various new and useful improvements in screw wrenches herein
described and shewn.
In witness whereof, I, the said William Thomas Weston, have hereunto
set my hand and seal, this Fourteenth day of April, in the year of our
Lord One thousand eight hundred and sixty-two.
Witness,
ALEX. PRINCE,
Agent for Patents,
4, Trafalgar Square,
Charing Cross.
W. T. WESTON. (L.S.)