IMPROVEMENTS IN SCREWS AND SCREWDRIVERS
Year: 1875

page_text: LETTERS PATENT to John Garrett Tongue, of the Firm of Tongue
& Birkbeck, Patent Agents and Engineers, of 34, Southampton
Buildings, Chancery Lane, in the County of Middlesex, for the
Invention of "IMPROVEMENTS IN SCREWS AND SCREWDRIVERS.”—A com.
munication from abroad by Allan Cummings, of the City, County,
Scaled the 6th July 1875, and dated the 22nd April 1875.
PROVISIONAL SPECIFICATION left by the said John Garrett Tongue
at the Office of the Commissioners of Patents, with his Petition,
on the 22nd April 1875.
I, JOHN GARRETT TONGUE, of the Firm of Tongue and Birkbeck,
Patent Agents and Engineers, of 34, Southampton Buildings, Chancery
Lane, in the County of Middlesex, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN SCREWS AND SCREWDRIVERS," a com-
munication to me from abroad by Allan Cummings, of the City, County,
and State of New York, United States of America, to be as follows:-
•
The object of this Invention is to provide a screw of any and all
varieties so constructed that it may be readily inserted and driven home

page_text: or withdrawn when desired with great rapidity and safety, and without
any danger of injuring the slot in the head or the head of the screw
itself by the slipping of the screwdriver. In order to accomplish these
purposes the center of the head is formed of any shape or size of screw
adapted for any purpose, a cavity of suitable shape and depth, into which
cavity a properly shaped screwdriver coinciding in shape with that of
the cavity is inserted for driving or withdrawing the screw. Or both the
cavity and the usual slot now formed in the screw head may be com-
bined, a screwdriver being used, the blade of which has a projecting spur
so formed that it will fit into both the slot and cavity, thus giving great
strength and power. Various forms of cavities in the screw heads and
correspondingly shaped screwdrivers may be made and used. Various
modes and forms may be employed and adapted for carrying out these
improvements, for instance, an ordinary screw may have a round head
and be provided with a cavity in the center of its head, or an ordinary:
wood screw may have cavity in the center of the head combined with
the usual slot, and the cavities may be of various shapes.
The blade of the screwdriver has a projecting spur, or it may be suit-
ably formed for use in scrow heads provided with a cavity only, or
detached points may be employed for use with the screwdrivers, adapting
them to various forms of screws. The slots in the heads may be shaped
half round or of other suitable form, the screwdrivers for use with such
screw heads corresponding in form therewith.
It is a well-known fact that the ordinary screw head provided with a
slot milled across its top and shallow in depth is very susceptible to
injury, caused mainly by the slipping of the screwdriver from the slot
when the screw is being driven home either in wood or metal.
It is in the removing or withdrawing of screws that this Invention
proves its great utility. Screws that have been long imbedded are rusted
in (as is of common occurence), are very difficult to remove with the
ordinary screwdriver, as it unvariably slips from the slot, repeating the
mishap until it is utterly impossible to start the screw from its bed or to
obtain a hold in the damaged slot with the screwdriver. The screw has
then to be removed by cutting it out, to the great damage of the work in
which it was located. This Invention obviates all this trouble, as the
screw having a cavity in its head is readily withdrawn at the first trial.
The cavity is made of such depth and shape as may in practice be

page_text: found best and necessary to fully accomplish the purposes of this Inven-
tion. It may be made tapering from the top to the bottom, or it may be
made of the same size for its entire depth, as preferred, the cavity being
either round, oblong, triangular, or octagonal. It is obvious that any of
these shapes will fully answer the purpose, therefor the Invention is not
confined to the use of any one particular shape. When the slot is
omitted from the head of the screw the angular shaped cavity will be
used; but when the slot and cavity are combined any shaped cavities
may be used; but in all cases it is desirable to use the angular cavity,
as it gives the greatest amount of power. These cavities may be formed
in the screw machine at the time the screw is being made by any of the
well-known mechanical processes, but this being no part of this Invention
the process requires no description here.
The blade of the driver may be similar in form of construction to that
of the ordinary screwdriver. The base of the blade is shaped so as to
fit into the ordinary slot; in the screw head at the center of the base of
the blade there is an angular, oblong, or round projecting spur, which is
made tapering or of same size its entire length, and of sufficient length
to nearly reach the bottom of the cavity in the screw head, while the
blade itself will enter the slot. This form of driver is for use whero the
screw head is provided with both cavity and slot, and by the use of such
form of screw head and screw driver the greatest possible amount of
power and strength is obtained; any desired degree of power may be
applied to this screwdriver and exerted to the utmost without any danger
of its slipping in the slightest or of injuring the screw head.
The form of screwdriver designed for use with screws the heads of
which are provided with a cavity only may be made tapering, and the
lower end angular or oblong, as the case may call for. In order to adapt
the screwdriver to both the ordinary screw and screws of the forms
herein described a series of extra points are employed for use therewith,
thus making them interchangeable.
The top of the screwdriver is provided with a longitudinal slot in
which an ordinary screwdriver will fit. Its base is formed with a com-
bined blade and projecting spur, as previously described. This detached
point when used with an ordinary screwdriver will drive or remove screws
having a cavity and slot.

page_text: In some cases it may be found to be desirable to vary the form of the
slot in the screw heads for the purpose of gaining more power and
strength than is now obtained by the ordinary straight slot.
It is obvious that the detached points may be varied in shape so as
to fit any one and all of the various forms of screws and screwdrivers
herein described.
This Invention may be applied to every and all of the known forms of
screws, both machine and wood, to machine bolts, carriage bolts, stonc
bolts, and to all bolts that are provided with a screw thread, and are
operated and used by means of a lever power applied to their heads.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Garrett Tongue in the Great Scal Patent
Office on the 22nd October 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
GARRETT TONGUE, of the Firm of Tongue and Birkbeck, Patent Agents
and Engineers, of 34, Southampton Buildings, Chancery Lanc, in the
County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-second day of April, in the year
of our Lord One thousand cight hundred and seventy-five, in the
thirty-eighth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said John Garrett Tongue, Her
special license that I, the said John Garrett Tongue, my executors,
administrators, and assigns, or such others as I, the said John Garrett
Tongue, my exccutors, 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 Ircland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN SCREWS AND SCREWDRIVERS," a communication to me
from abroad by Allan Cummings, of the City, County, and State of New
York, United States of America, upon the condition (amongst others)
that I, the said John Garrett Tongue, my executors or administrators,
by an instrument in writing under my, or their, or one of their hands

page_text: Figure 10 is an elevation or plan view of a screwdriver for use in
screw heads provided with a cavity only.
Figures 11 and 12 are plan views of detached points for use with the
screwdrivers, adapting them to the various forms of screws.
Figure 13 is a plan view of a screwdriver, as shown in Figure 9,
strengthened by the use of shoulders.
Similar letters of reference indicate corresponding parts.
It is a well known fact that the ordinary screw head provided with a 1
slot milled across its top and shallow in depth is very susceptible to
injury, caused mainly by the slipping of the screwdriver from the slot
when the screw is being driven home, either in wood or metal.
In very many cases the screws that are damaged in that way are
necessarily cast aside as useless, not being in keeping with the finished 1
work into which they are inserted. This loss of screws annually amounts
to a very large sum. It is to obviate these difficulties, to gain additional
strength and power, and to render it absolutely impossible to damage
the screw head, that the present Invention and improvement has been
devised.
Large quantities of what are known in commerce and trade as "capped
screws" are now made and used in finishing up the interior of cars,
coaches, buildings, and furniture, and in fact wherever a handsomely
finished and ornamental screw head is desired. The heads of such
screws, cither flat or rounded, are covered with a thin metallic plate, 2
which is plated with gold, silver, nickel, or other metal, as may be
preferred. This metallic cap being very thin it requires the utmost
care and nicety to use these screws and to drive them into place with the
ordinary screwdriver without displacing or injuring the cap. By
omitting the usual slot from the heads of screws of this class and using 3
in lieu thereof a cavity and screwdriver of the proper form perfect
safety is insured to the metallic cap. The screw head also presents a
more ornamental appearance, the process of capping is also simpliefied
by reason of the absence of the slot.
Large quantities of screws, screw bolts, stove and other bolts, are mado 3
2

page_text: the blade, as at d, is shaped so as to fit into the ordinary slot in the
screw head. At the centre of the base of the blade there is an angular,
oblong, or round projecting spur f, which is made tapering or of
same size its entire length, and of sufficient length to nearly reach the
bottom of the cavity in the screw head, as in Figure 2, while the blade 5
itself will enter the slot. This form of driver is for use where the screw
head is provided with both cavity and slot, and by the use of such form
of screw head and screwdriver the greatest possible amount of power
and strength is obtained. Any desired degree of power may be applied
to this screwdriver and exerted to the utmost, without any danger of its 1
slipping in the slightest or of injuring the screw head.
In Figure 10 the form of screwdriver is shown designed for use with
screws, the heads of which are provided with a cavity only, and it may
be made tapering, and the lower end angular or oblong, as the case may
require.
In order to adapt the screwdriver to both the ordinary screw and
screws of the forms as herein shown and described, a series of extra
points are designed for use therewith, thus making them interchangeable.
In Figure 11 such a point drawn full size is shown. At the top it is
provided with a longitudinal slot, in which an ordinary screwdriver will 2
fit, and its base is formed with a combined blade and projecting spur, as
previously described and shown in the case of the driver shown in
Figure 9. This detached point when used with an ordinary screwdriver
will drive or remove screws having a cavity and slot.
In Figure 12 a detached point is shown drawn full size. At the top 2
it is provided with both the slot and cavity of same shape and form
as shown in the screw in Figure 2; its base is the same as that of an
ordinary screwdriver. This detached point is for use in the moving of
ordinary screws with a slot only, and is to be attached for that purpose
to the base of the screwdriver formed as shown in Figure 9.
In some cases it may be found to be desirable to vary the form of
the slot in the screw heads for the purpose of gaining more power and
strength than is now obtained by the ordinary straight slot.
Figure 13 shows a portion of a screwdriver (such as shown in Figure 9)
having its projecting spur reinforced by means of the shoulders Is for
the purpose of increasing its strength. When this form of driver is
used the cavity and slot in the head of the screw must be shaped
accordingly.

page_text: It is obvious that the detached points shown in Figures 11 and 12 may
be varied in shape so as to fit any one and all of the various forms of
screws and screwdrivers herein shown and described.
This Invention mry be applied to every and all of the known forms of
screws, both machine and wood, to machine bolts, carriage bolts, stove
bolts, and to all bolts that are provided with a screw thread, and are
operated and used by means of a lever power applied to their heads.
Having thus fully described the nature of this Invention, and the
manner of performing or carrying the same into practice, what I claim
under the above in part recited Letters Patent is,―
First. An improved screw of any form or shape, the head of which is
provided at its centre with an angular, oval, oblong, or round cavity in
combination with or without the ordinary and usual slot arranged,
combined, and operated substantially as and for the purposes as herein
shown and described.
Second. An improved screwdriver, the blade of which at the centre of
its base is provided with an angular, oblong, or round projecting spur,
arranged and operating substantially as and for the purposes hercin
shown and described.
Third. The improved detached points, as shown in Figures 11 and 12,
provided with slots, cavities, and spurs, for the purpose of interchanging
with ordinary slotted screws and ordinary screwdrivers, and with screws
and screwdrivers provided with slots, cavities, and spurs, or vice versa,
substantially as and for the purposes as herein shown and described.
Fourth. An improved screw having formed in its head an ordinary
slot, and provided with an angular, oval, or round cavity extending
below its base, substantially as and for the purposes herein fully described
and set forth.
In witness whereof, I, the said John Garrett Tongue, have here-
unto set my hand and seal, this Twenty-second day of October