IMPROVEMENTS IN CORKSCREWS
Year: 1876

page_text: PROVISIONAL SPECIFICATION left by George Arthur Biddell at the Office of
the Commissioners of Patents on the 12th June 1876.
GEORGE ARTHUR BIDDELL, of Ipswich, in the County of Suffolk, Engineer.
"IMPROVEMENTS IN CORKSCREWS."
The Invention has for its object improvements in corkscrews.
the same.
For this purpose I make the screw and worm or threaded parts of corkscrews
stronger and stiffer than usual by forming the threads or worms solid with a taper
or parallel core or central portion of the screw or stem, which central part terminates
in a sharp point projecting beyond the end of the flat thread or worm so as to enter
the cork readily and preserve the direction of motion centrally and truly through
The threads or worms admit of being made thus quite true and of a
regular pitch without difficulty, which regularity will not vary in use by easily
becoming bent or strained, and they are made parallel or nearly parallel on the
outer diameter of the threads or worms, and not smaller in this diameter towards
the point, which is a great defect in the worms or threads of corkscrews as hitherto
made. My object in thus making the screw parts, threads, or worms is to ensuro
a firm unyielding springless hold upon the cork, specially at or near the bottom or
inner end of the same, and thus to have the cork mostly in compression in the act
of being drawn, so as in effect to get the action on the cork nearly as it would be if
it were pushed out from the inside end, and not chiefly in extension, as is the case
in the corkscrews with twisted and taper threads or worms as hitherto made, and Fo
acting greatly on the cork as if it were being pulled out chiefly by the hold being
taken at or near the top of it, a strain which the nature of cork is not calculated to
resist without breaking up or pulling to pieces.
The irregular pitch of the twisted worms of all kinds of corkscrews now generally
in use arising either from want of accuracy in their first formation (owing to the
difficulty of getting them accurately twisted), or from constant straining in use,
or ready accidental bending, and their tendency to stretch out of pitch when hard
pulled, are all obvious causes of their so frequently breaking up and separating the
cork into pieces instead of withdrawing it whole. And the want of a firm hold at
the bottom or inside end of the cork is another source of the same bad effect, all of
which defects are avoided by making the screw solid with flat threads or worms,
and by making the threads or worms deep at and near the point of screw instead of
weak and tapering towards the point as heretofore.
Corkscrews such as above described may readily be cast with their threads
complete (and with handle or cross bar also if desired) of any suitable metal, such

page_text: as gun metal, or other proper mixtures of metals, as well as of tough cast iron, or
malleable cast iron or steel, which can be annealed as much as requisite. This
facility of casting greatly cheapens the cost of production. If desired the screws
can be cut (in the same way as ordinary wood screws), or stamped in wrought iron,
steel, or any suitable material.
The screws can also be adapted to any of the present simple or compound forms
of corkscrews now in use.
My improvements also consist in forming at or near the top of the screw or
threads or worms a gradually increasing swell, cone, or projecting collar on the
shank of the instrument so that the cork is forced on to and upon this projecting
cone after being withdrawn from the bottle by screwing or turning on in the same
direction as before drawing the cork which is thus split open, and is by this means
more quickly and readily removed sideways from the screw and stem than by
unscrewing by turning the cork or screw in the reverse way as usual in taking the
cork off the present instruments hitherto used.
This part of my Invention is not only applicable to my new screw portions above
described but to all kinds of twisted or otherwise formed screws for drawing
corks, and is one of the distinctive practical features of this Invention applicable to
all descriptions of corkscrews now in use.
My improvements further consist in attaching a short sharp narrow cutting knife
with one or more blades (by preference two blades) transversely to the pointed end
of the screw, letting the point project through a boss in the knife, and allowing this
knife free motion round the point, but confining endways of the boss by shoulders
or a pin. By this means when the point and knife are forced into the cork and the
screw turned down into the same the blade or blades of the knife will cut the cork
nearly in pieces longitudinally, the blades of the knife being rather less across from
tip to tip than the diameter of the cork at its smallest part so as to clearly pass
through the neck of the bottle, and when the cork is withdrawn it will be readily
removed from the screw sideways with a very slight force of the hand, or by a
small bursting cone or projection on the stem, as described above.