AN IMPROVED ADJUSTING SPANNER
Year: 1870

page_text: PROVISIONAL SPECIFICATION left by Robert Francis Drury at the
Office of the Commissioners of Patents, with his Petition, on the
17th February 1870.
I, ROBERT FRANCIS DRURY, of Sheffield, in the County of York, do
hereby declare the nature of the said Invention for "AN IMPROVED
ADJUSTING SPANNER," to be as follows:-
The said Invention relates to improvements in the construction of the
implement commonly known as the "Clyburn spanner," which is a key
or wrench for screwing and unscrewing screw nuts and bolts. The said
spanner consists of a lever or handle provided with two jaws, one forged
or otherwise made solid or in one piece with the lever or handle, while
the other jaw is adjustable to allow the spanner to be fitted to various
sized nuts or bolt heads. The said moveable jaw is fitted to slide in a
groove in the head of the spanner, and has screw threads formed on its
bottom or inner edge, in which screw threads a small worm or screw
roller is fitted to work. The head of the spanner is formed with an
opening through it, whereby the said roller or worm is accessible, so that
it
may be turned by the thumb and finger to adjust the spanner to any
required size.

page_text: My present Invention is designed to reduce the cost of manufacture of
the aforesaid implement, and to render it more simple of construction
and more convenient to use. In the ordinary manner of constructing
the said "Clyburn” spanners the actuating worm or screw roller is fitted
to turn upon a pin or rod which is secured in the head of the spanner,
consequently the said worm or screw roller cannot be removed from the
spanner without first releasing and driving out the pin.
According to my improved method of construction I form solidly on
the said worm or screw roller short journals or studs, which are fitted to
turn in bearings in the central part of the head, to which access may
be conveniently had through the central opening made to permit the
manipulation of the worm. The said bearings only partly enclose the
journals, and if the moveable jaw is withdrawn the worm or screw roller
may be easily released from its bearings, but when the said jaw is in its
place in the head, the worm having the said jaw on one side of its axis
and the bearings on the other side thereof, is securely retained in the
said bearings. This method of supporting the worm is very simple and
inexpensive, and allows the said worm or roller to be easily, inserted
into or removed from the implement and conveniently lubricated, and
diminishes the number of the parts of which the implement is composed.
The inner part of the moveable jaw of the said "Clyburn" spanner fits
the groove in the head and supports the moveable jaw firmly while
allowing it to slide therein, the said inner or guiding part being long
enough to allow the required extension or opening of the jaws.
Hitherto in these implements this guiding or toothed part has been
rectangular in cross section, and therefore the groove in which it slides
has of necessity been rectangular also.
In my improved implement this guiding part and groove are preferably
made circular, or nearly so; I therefore avoid the labor and cost of
forming a square shoulder on the guide, and a square or rectangular
groove through the head of the spanner. The said circular or guiding
part is united to the outer portion of the jaw by an intermediate web,
which requires only a narrow opening in which to slide. I do not
however restrict myself to only making this guiding part and groove
circular in cross section, as my improved solid roller or worm can be
used with the square-shouldered loose jaw as in the old method of
constructing the implement.

page_text: In putting the parts together the roller or worm is first placed in its
bearings. The moveable jaw is then inserted into its groove, then by
turning the roller or worm the jaw is drawn into its place. To remove
these parts it is only necessary to turn the worm or roller until the
moveable jaw is released from its threads, the jaw and roller or worm can
then be taken out.
I prefer that the threads of the roller or worm and jaw should be
square or rectangular, and that the periphery of the said roller or worm
should be milled or roughened. The central opening in the spanner
head is made conformable to the configuration of the roller or worm and
its journals, that is to say, the parts of such openings where the bearings
are formed need only be of sufficient width to allow the journals to pass
when raised out of the bearings.