An Improvement in Screw Drivers.
Year: 1893

page_text: Date of Application, 13th June, 1893
Complete Specification Left, 14th July, 1893-Accepted, 19th Aug., 1893
PROVISIONAL SPECIFICATION.
An Improvement in Screw Drivers.
I, ARNULPH MALLOCK, of No. 3 Victoria Street, in the County of London, do
hereby declare the nature of this invention to be as follows:-
In turning a screw driver, it is difficult to keep its axis in line with that of the
screw to which it is applied, and consequently its chisel end is liable to escape from
the notch of the screw or to act so unequally as to deform the notch. My invention
relates to a construction of screw driver by which these difficulties are overcome.
For this purpose, I make the shank of the screw driver with its end part round and
terminating in a hemisphere, cone or conoid. On this rounded part 1 fit somewhat
loosely a socket which is held in place by a cross pin passed through the stem and
through lateral holes of the socket, which holes are elongated so that the socket,
loosely fitting the end of the shank, can rock upon it, as it were on a spherical
joint, but must turn with it. The face of the socket has a central projecting rib
which acts as the chisel end of an ordinary screw driver when inserted in the notch
of a screw, but, owing to the freedom which the socket has to rock, moderate
deviation of the shank from the axial line of the screw does not tend to make the
chisel rib escape from the notch. I prefer to make the face of the socket with a
slight rounded hollow on each side of the projecting rib so that there is no sharp
angle at the base of the rib.
Dated this 13th day of June 1893.
דמי
ABEL & IMRAY,
Agents for the Applicant.
COMPLETE
SPECIFICATION.
An Improvement in Screw Drivers.
I, ARNULPH MALLOCK, of No. 3 Victoria Street, in the County of London, do
hereby declare the nature of this invention and in what manner the same is to
be performed to be particularly described and ascertained in and by the following
statement:
In turning a screw driver, it is difficult to keep its axis in line with that of
the screw to which it is applied, and consequently its chisel end is liable to escape
from the notch of the screw, or to act so unequally as to deform the notch. My
invention relates to a construction of screw driver by which these difficulties are
overcome. For this purpose, I make the shank of the screw driver with its end
part round and terminating in a bemisphere, cone or conoid.
On this rounded part fit somewhat loosely a socket which is held in place
by a cross pin passed through the stem and through lateral holes of the socket,
which holes are elongated so that the socket, loosely fitting the end of the shank,
can rock upon it, as it were on a spherical joint, but must turn with it. The face
of the socket has a central projecting rib which acts as the chisel end of an ordinary
screw driver when inserted in the notch of a screw, but, owing to the freedom which
the socket has to rock, modcrate deviation of the shank from the axial line of the
screw does not tend to make the chisel rib escape from the notch. I prefer to
make the face of the socket with a slight rounded hollow on each side of the
projecting rib so that there is no sharp angle at the base of the rib.
In the accompanying drawings I shew, by way of examples, several different ways
in which my invention can be carried out.

page_text: Fig. 1 is a section partly in elevation and Fig. 2 is a side view shewing a con-
struction in which the socket S has an internal pivot A bearing in a countersunk
hollow formed in the end of the shank B which is made with pins P projecting at
both sides into slots formed in the socket these slots being closed by filling pieces F
brazed or otherwise fixed in the slots after the end of the shank and its pins have
been introduced into the socket. The closing of the slots may be effected, as shewn
in Fig. 3, by cutting a slit on each side of the slot and bending in the metal between
these slits and the slot as indicated at f. Figs. 4 and 5 shew the shank made with
an end spherical or nearly so, a pin P being passed in through the slots of the
socket and the spherical head. As shewn in Figs. 6 and 7, the socket has
the spherical end of the shank and its lateral pins retained in it by a cap C
screwed in.
In all the figures above referred to, the rib R, which serves as the operating
chisel end of an ordinary screw driver, is shewn with a rounded hollow at each side.
This construction is preferred as there is thus less risk of the rib breaking off the
socket than there would be if there were angles at the springing of the rib from the
socket. Moreover as sometimes there is a burr on the head of a screw where it is
slotted to receive the screw driver, the hollow on each side of the rib allows of the
face of the socket bearing evenly on the whole head of the screw notwithstanding
there may be such burrs.
I have shewn by way of example several constructions by which the screw
driver shank can be provided with a socket free to rock to a certain extent on it,
but obviously the construction and form of the end of the shank and of the
socket which receives it may be varied, provided that while the socket must turn
with the shank, it has freedom to rock on it sufficiently to allow for the ordinary
deviation of the hand from the axial line in turning a screw driver.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
A screw driver having on the end of its shank a socket having a projecting rib to
enter the slot of a screw, this socket being so connected to the end of the shank that
it must turn with it, but is free to rock upon it, substantially as and for the purpose
set forth.
Dated this 10th day of July 1803
ABEL & IMRAY,
Agents for the Applicant.