AN IMPROVED SCREW WRENCH
Year: 1855

page_text: LETTERS PATENT to John Talbot Pitman, of the American and European
Patent Offices, 67, Gracechurch Street, London, for the Invention of
A sammunication
Sealed the 20th March 1856, and dated the 28th September 1855.
PROVISIONAL SPECIFICATION left by the said John Talbot Pitman at
the Office of the Commissioners of Patents, with his Petition, on the
28th September 1855.
I, JOHN TALBOT PITMAN, of the American & European Patent Offices, 67,
Gracechurch Street, London, do hereby declare the nature of the said Inven-
tion for "AN IMPROVED SCREW WRENCH," a communication made to me by a
certain person residing abroad, to be as follows:-
In constructing the collar of the moveable jaw, and connecting therewith a
spring or lever by suitable arrangements, in a manner such that by pressing
upon the end next the handle the screw attached to it shall be pushed out of
gear, and the jaw can while the pressure continues be moved to the desired
position of adjustment.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Talbot Pitman in the Great Seal Patent Office on the
28th March 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
TALBOT PITMAN, of the American and European Patent Offices, 67, Grace-
church Street, London, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-eighth day of September, in the year of our
Lord One thousand eight hundred and fifty-five, in the nineteenth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said John Talbot Pitman, Her special licence that I, the said John
Talbot Pitman, my executors, administrators, and assigns, or such others as I,
the said John Talbot Pitman, 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 "AN
IMPROVED SCREW WRENCH," a communication, upon the condition (amongst
others) that I, the said John Talbot Pitman, my executors or administrators,
by an instrument in writing under my, or their, or one of 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 John Talbot Pitman, 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, reference being had to the accompanying Drawings; in which,
Figure 1 represents the wrench; Figure 2, a section of the movable jaw and
spring Figure 3, the jaw operated by the lever; Figure 4, the lever. The
same letters indicate the same parts of the wrench in all the Figures.
The Invention consists in the manner of making and attaching the movable
jaw used in the ordinary hand wrench, so that it can be readily and quickly
adjusted to the object.
The construction of the wrench may be described as follows:-The movable
jaw B slides in the usual way on the bar or handle A, and while it has no
lateral play on this handle, there is between them left a space, so that the jaw
is free to move in the other direction, that is, from front to back, and the
reverse. The internal faces of the jaw in this direction may in some cases be

page_text: parallel, and in others not, to the faces of the handle. If it be desirable
that they should not be parallel, the cavity of the jaw will be enlarged
from the end next the stationary jaw, increasing gradually towards the end
next the handle, so that the jaw will have more play at the end last mentioned
on the handle. In order to keep the front internal face of the jaw always in
contact with the front face of the handle when there is no counteraction, a
spring D of a convex form is introduced on the back, so that when its extre-
mities rest against the rear internal face of the jaw, and its centre against the
rear face of the handle, it will produce the effect desired. To the jaw B next
to the handle A' is attached a screw C, playing loose on the shaft F, or it may
be only a series of spiral projections made stationary, either of them fitting
into corresponding indentations in the bar A, the object being to keep the jaw
stationary, by preventing when these are in contact any movement of it on the
bar. On the jaw B at E is a button; when this or the jaw in its neighbour-
hood is pressed by the operator, the spring D acting also the part of a lever,
of which the point of rest on the bar is the fulcrum, allows the jaw to be
forced out of gear. When the jaw is adjusted to the place where it is to
remain, the pressure is removed, the screw again comes into gear, and the
jaw is stationary.
I also use, instead of the spring D, above described, a spring lever F, as
represented in Figures 3 and 4. By pressing upon the handle of the lever,
its other extremity bears sufficiently hard upon the bar to force, as in the
other mode, the screw out of gear. In this arrangement the space between
the jaw and the bar is not so large at the end next the stationary jaw, for
the play will be less, as at that next the handle, and the adjustment may
be effected more easily.
Having now described the nature of the said Invention, what I claim, and
desire to secure by Letters Patent, is, the construction of the movable jaw,
with the collar or eye of an aperture of greater section, as within described,
than the bar on which it slides, and operating it by a spring or lever sub-
stantially as within described.
In witness whereof, I, the said John Talbot Pitman, have hereunto set
my hand and seal, this Twenty-seventh day of March, Anno Domini
One thousand eight hundred and fifty-six.
JOHN TALBOT PITMAN. (L.S.)