Improvements in Screws and the like, and in Turnscrews therefor.
Year: 1899

page_text: Date of Application, 13th Feb., 1899
Complete Specification Left, 10th Nov., 1899-Accepted, 20th Jan., 1900
Improvements in Screws and the like, and in Turnscrews therefor.
I, JOHN HENRY BARKER, of GG, Park Parade, Cambridge, Electrical Engineer,
do hereby declare the nature of this invention to be as follows:-
My invention relates to improvements in screws and the like, and in turn-
screws for operating the same, and has for its object more especially to meet a
want in connection with screws used for coupling electric conductors. There has
been hitherto great difficulty in disconnecting a section of electric conductors
where they are joined together in a junction box, owing to a screw when slack-
ened and just clear of its thread, falling into the bottom of the box, or into such
a position that it short circuited the conductors, or into a position where it
could not be readily got at. Also on high tension circuits when the conductors
are live there is some dithculty in touching the metal screws with the hand owing
to the liability of getting a shock through the body.
Such screws can also be used with advantage in any confined space where
they cannot easily be reached with the fingers.
My invention consists in forming the head of the screw with a slit, which is
wider at the bottom than at the top, so that when a screw-driver with a corre-
sponding enlargement on its point is passed in laterally into the slit, it will lift
the screw, and in providing a friction grip for the screw head to prevent it fail-
ing off the screw driver laterally.
In carrying my invention into effect according to one modification, say as
applied to a cheeseheaded screw, I provide an enlargement at the bottom of
the slit, preferably formed by boring a hole through the cheese head at right
angles to the length of the screw, and then forming the slit by means of a saw,
so that the slit passes into the previously bored hole. The hole should be larger
than the width of the slit.
One form of turnscrew, suitable for such a screw, has an enlargement at its
point slightly smaller than the size of the bored hole, and is so formed above
the enlargement that the turnscrew can be passed laterally on to the screw head.
I prefer to provide a sleeve on the turnscrew, adapted to grip the screw head
by friction, as the turnscrew is brought into engagement with the screw head.
This sleeve might either be a rubber ring of suitable shape, or a metal sleeve
pressed down against the screw head by a spring, and in the latter case the part
of the sleeve which bears on the screw head should be curved, so that the lowest
point of the curve is in the centre of the turnscrew blade, and the sleeve should
be provided with a stop, to prevent it coming too far down when the sleeve is
against the stop, that is, in its furthest down position. The enlargement on
the point of the turnscrew is sufficiently below the edge of the curved part of the
sleeve to enable the turnscrew to be entered onto the screw head. As the turn-
screw is pushed properly on to the screw head it presses back the sleeve against
the spring and thereby is gripped against the projection on the point of the
turnscrew.

page_text: A sleeve such as described above may not be necessary where the screws are
in vertical situation and can be lifted out vertically.
Dated this 13th day of February 1899.
MARKS & CLERK,
18, Southampton Buildings, London, W.C.,
13, Temple Street, Birmingham, and
25, Cross Street, Manchester, Agents.
JOHN HENRY BARKER, of 66, Park Parade, Cambridge, Engineer, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement;
My invention relates to improvements in screws and the like, and in turnscrews
or screw-drivers for operating the same, and has for its object to meet a want
in connection with screws used for coupling electric conductors. There has been
hitherto great' difficulty in disconnecting a section of electric conductors where
they are joined together in a junction box owing to a screw, when slackened
and just clear of its thread, falling into the bottom of the box, or into such a
position that it short circuited the conductors, or into a position where it could
not readily be got at. Also on high tension circuits when the conductors are
live, there is some difficulty in touching the metal screws with the hand owing
to the liability of getting a shock through the body.
My invention consists in forming the head of the screw with a suitable slit
which is wider at the bottom than at the top so that, when a screwdriver with
a coresponding enlargement on its point is passed laterally into the slit, it will
lift the screw; and in providing a friction or other suitable grip for the screw
head to prevent it falling off the screw-driver laterally.
Referring now to the accompanying drawings, which illustrate my invention,
Figure 1 is an elevation, and
Figure 2 is a plan of a screw made according to one modification of my
invention.
Figures 3 and 4 show similar views according to another modincation of my
invention.
Figure 5 shows a screw-driver made according to one modification of my
invention.
Figures 6 and 7 are respectively front elevation and cross section of the end
of this screw-driver drawn to a larger scale, and
Figure 8 shows the end of the screw-driver with a screw affixed.
Figure 9 shows a screw-driver made according to another modification of my
invention.
Figures 10 and 11 are respectively front elevation and cross section of the end
of this modified form of screw-driver drawn to a larger scale, and
Figure 12 shows the end of the screw-driver with a screw affixed.
Figures 13, 14 and 15 are respectively front and side elevations and plan of
a screw-driver made according to a third modification.
In the head of the cheese-headed screw shown in Figures 1 and 2, I provide
a slit a and an enlargement b which are preferably formed by boring a hole b
through the cheese-head at right angles to the length of the screw and then
forming the slit a, by means of a saw, so that the slit passes into the previously 5
bored hole, and is in one plane with it. The hole should be larger than the width
of the slit.

page_text: One form of screw-driver suitable for use with such screws is illustrated in
Figures 5, 6, 7 and 8. m is the handle of wood or other insulating material
and d is the blade. n is a sleeve of vulcanite slipped over the fast end of the
blade to allow the screw-driver to be safely held at this place while in contact
with a screw in a high tension electric circuit. The blade d is enlarged at its
end e so as to be an easy fit in the slit and enlargement in the head of the screw.
It is an advantage to have the enlargement e tapered away slightly at the ends
or else to have the slit in the screw head widened a little at the ends to facilitate
the entering of the end of the screw-driver into the slit. Near the end of the
screw-driver blade is a metal sleeve f which is pressed out by a spring g which
butts against the projection h. The sleeve is prevented from being pushed out
too far by a projection on the blade of the screw-driver coming in contact with
the end of a slot in the sleeve f or by any other suitable means.
The end e of the screw-driver is slid laterally into the groove in the screw-head,
the sleeve being pressed back against the action of the spring g. The sleeve
is rounded at its outer end o to facilitate the entering of the end of the blade
into the groove in the screw-head. The screw-driver is shown entered in Figure 8
and ready to turn the screw. In this position the sleeve f is pressed against
the screw-head and the friction so produced prevents the screw from falling offi
the end of the screw-driver when withdrawn from its hole.
Instead of having a metal sliding and spring pressed sleeve I may have a fixed
rubber sleeve of similar shape, the effect of which will be the same.
Figures 3 and 4 show a modified form of screw, and Figures 9, 10, 11 and 12
a modified form of screw-driver suitable for use with it. The screw is the same
as my first modification illustrated in Figures 1 and 2, but has in addition a
semicircular groove on each side of the slit and parallel to the length of the
screw. Instead of the slot in the screw head being of uniform width with an
enlargement at its end it may in this modification be of dovetailed form. The
screw-driver also resembles my first modification, but, instead of the sleeve fi
there is along one side of the blade a wire y one end r of which enters one of the
semicircular grooves in the screw-head while the other end is attached to a
vulcanite or other insulating pins by which the wire can be pulled in against
the action of the spring t. The wire is constrained to move in its own line by
means of a groove in the screw-driver blade and by guide pieces u. When the
screw-driver blade is being entered into the slit in the screw-head, the wire is
drawn back by means of the pin s and, when the blade is in position the pin s
is let go and the free end of the wire enters one or other of the semicircular
grooves and prevents the screw sliding laterally off the end of the screw-
driver.
Figures 13, 14 and 15 show the end of another modified form of my screw-
driver. The end of the blade is here split into two parts and and the
width of the enlarged top is rather more than the width of the slit in the screw-
head so that, when the end of the blade is entered into the slit in the screw-head
the parts wand will be forced together. These parts will therefore press out
against the sides of the slit in the screw-head and the resulting friction will
prevent the screw from sliding laterally off the end of the blade. To facilitate
the entering of the parts w and a into the screw-head slit they are bevelled away
at their ends Y.
The devices herein before described for preventing the screws from sliding
laterally off the end of the screw-driver are not so necessary when the screws
are in vertical situation and can be lifted vertically. In such a case the screw-
driver may be constructed without any of the said devices.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:
1. A screw having in its head a slit such as a with an enlarged groove such

page_text: as b adapted to receive a suitable screw-driver substantially as; and for the pur-
pose herein before described with reference: to Figures 1 and 2.
2. A screw having a head with a slit enlarged or dovetailed at its 'bottom
and a groove such as p at one or both sides of the slit, substantially as and for
the purpose herein before described with reference to Figures 3 and 4.
3. A screw-driver with an enlarged end adapted to operate screws as claimed
in Claims 1 and 2 substantially as hereinbefore described with reference to the
accompanying drawings.
4. A screw-driver with an enlarged end and a friction screw gripping device
substantially as and for the purpose herein before described:
1
1
5. A screw-driver with its blade split in two parts and each part enlarged
externally at its end with the enlargements bevelled away at their extremities,
substantially as and for the purpose described with reference to Figures 13, 14
and 15.
6. A screw-driver with an enlarged end and a sliding wire adapted to hold
a screw, substantially as and for the purpose hereinbefore described with refer-
ence to the accompanying drawings.
7.
The improved screw-drivers and screws. adapted to be operated thereby
as herein before described with reference to the accompanying drawings.
Dated this 9th day of November 1800
MARKS & CLERK,
18, Southampton Buildings, London, W.C.,
13, Temple Street, Birmingham, and
25, Cross Street, Manchester, Agents.
MARKS & CLERK,
18, Southampton Buildings, London, W.C.,
13, Temple Street, Birmingham, and
25, Cross Street, Manchester, Agents.