IMPROVEMENTS IN SCREWDRIVERS
Year: 1875

page_text: LETTERS PATENT to William Knell, of Park House, Farnborough,
in the County of Hants, for the Invention of "IMPROVEMENTS IN
SCREWDRIVERS."
Sealed the 13th June 1876, and dated the 29th December 1875.
PROVISIONAL SPECIFICATION left by the said William Knell at the'
Office of the Commissioners of Patents, with his Petition, on the
29th December 1875.
I, WILLIAM KNELL, of Park House, Farnborough, in the County of
Hants, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN SCREWDRIVERS," to be as follows:-
This Invention has for its object improvements in screwdrivers.
In constructing screwdrivers according to this Invention I form them
with a flat circular end to rest against the top of the screw heads.
Projecting from this flat end are ribs or projections, or it might be a
single rib or projection to enter cross cuts or recesses in the head of the

page_text: screw. The flat end of the driver may also be formed either with or
without a central pin projecting from it to act in the manner described
in the Provisional Specification lodged by me on the 3rd day of November
1875, No. 3825.
In addition to forming the driver with a flat circular end, I also
combine with it clips to lay hold of the head of the screw, and keep it
up to and against the flat end of the driver. This clip may lay hold of
the outer circumference of the head, or enter notches in it, or may be
formed with claws to bear against the sloping sides with which the head
of a wood screw is ordinarily formed. The clip may be formed of a tube
capable of sliding endwise upon the circular stem of the driver, and
which has longitudinal slits formed in its forward end. The separate
slips so formed at the forward end of the tube are set to spring slightly
outwards, so that they may readily pass over the head of a screw.
When a screw has been placed on to the end of the driver, this clip tube
is moved forward so as to pass the ends of the spring clips over the head
of the screw; the spring-clips are then, by moving forward a collar which
surrounds them, forced inwards and caused to lay hold of the screw
head. The screw is by this means securely held to the end of the driver,
and may easily be screwed into hard wood without its being necessary
to previously bore a hole for it. The tube at its rear end I connect to a
coiled spring, which tends to draw the tube backwards and retain its
forward end in rear of the end of the driver.
When a screw has been nearly screwed home the collar which forces
the clips against the screw head is moved back, and the clips free them-
selves from the screw head and are drawn back in the rear of the end
of the driver by means of the coiled spring above mentioned; the driving
home of the screw can then be completed. I also combine clips to act
in the manner above described with what I call skeleton drivers
adapted for driving screws with two or more cuts across the head. By
the term skeleton drivers I mean drivers not having a flat circular end
to rest against the head of the screw, but only formed to enter the cross
cuts in the head.
The stem of the screw driver may be formed so that it may be held in
and driven by an ordinary centre bit, or the stem of the driver may at
its end have a circular or other knob or handle pivotted to it, so that
when screwing in a screw the driver may by a constant pressure being

page_text: put upon the knob be continuously forced against the screw head. A
portion of the stem of the driver may in this case be made polygonal in
cross section, to enable a firm hold to be obtained of it to allow of its
being turned like an ordinary screw driver.
Provision may also be made for fastening the knob to the stem when-
ever desired, so that the screwdriver may then be turned by the knob or
handle at its end.
The stem of the driver may also be suitably formed to have applied to
it whenever desired a ratchet and lever by which it may be turned, or
other means may be adopted for turning the stem of the driver.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Knell in tlie Great Seal Patent Office on
the 29th June 1876.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
KNELL, of Park House, Farnborough, in the County of Hants, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-ninth day of December, in
the year of our Lord One thousand eight hundred and seventy-five,
in the thirty-ninth year of Her reign, did, for Herself, Her heirs
and successors, give and grant unto me, the said William Knell, Her
special license that I, the said William Knell, my executors, adminis-
trators, and assigns, or such others as I, the said William Knell, my
executors, 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
Ireland, the Channel Islands, and Isle of Man, an Invention for "Iж-
PROVEMENTS IN SCREWDRIVERS," upon the condition (amongst others) that
I, the said William Knell, my executors or administrators, by an instru-
ment in writing under my, or their, or one of their hands and seals,
should particularly describe and ascertain the nature of the said Inven-
tion, and in what manner the same was to be performed, and cause
the same to be filed in the Great Seal Patent Office within six

page_text: calendar monts next and immediately after we are
Patent.
NOW KNOW YE, that I, the said William Knell, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement thereof, that is to say :-
:
-
This Invention has for its object improvements in screwdrivers.
In constructing screwdrivers according to this Invention, I form them
with a flat circular end to rest against the top of the screw heads.
Projecting from this flat end are ribs or projections, or it might be a
single rib or projection, to enter cross cuts or recesses in the head of the
screw. The flat end of the driver may also be formed either with or
without a central pin projecting from it to act in the manner described
in the Provisional Specification lodged by me on the 3rd day of
November 1875, No. 3825.
In addition to forming the driver with a fiat circular end, I also
combine with it clips to lay hold of the head of the screw and keep it
up to and against the flat end of the driver; this clip may lay hold of
the outer circumference of the head or enter notches in it, or may be
formed with claws to bear against the sloping sides with which the head
of a wood screw is ordinarily formed. The clip may be formed of a tube
capable of sliding endwise upon the circular stem of the driver, and
which has longitudinal slits formed in its forward end. The separate
slits so formed at the forward end of the tube are set to spring slightly
outwards, so that they may readily pass over the head of a screw.
When a screw has been placed on to the end of the driver, this clip tube
is moved forward so as to pass the ends of the spring clips over the head
of the screw; the spring clips are then by moving forward a collar which
surrounds them, forced inwards and caused to lay hold of the screw head.
The screw is by this means securely held to the end of the driver, and
may easily be screwed into hard wood without its being necessary to
previously bore a hole for it. The tube at its rear end I connect to a
coiled spring, which tends to draw the tube backwards and retain its
forward end in rear of the end of the driver.
When a screw has been nearly screwed home, the collar which forces
the clips against the screw head is moved back, and the clips free them-
selves from the screw head, and are drawn back in the rear of the end of

page_text: the driver by means of the coiled spring above mentioned, the driving
home of the screw can then be completed. I also combine clips to act
in the manner above described with what I call skeleton drivers adapted
for driving screws with two or more cuts across the head. By the term
skeleton drivers I mean drivers not having a flat circular end to rest
against the head of the screw, but only formed to enter the cross cuts in
the head.
The stem of the screwdriver may be formed so that it may be held in
and driven by an ordinary centre bit, or the stem of the driver may at
its end have a circular or other knob or handle pivotted to it, so that
when screwing in a screw the driver may by a constant pressure being
put upon the knob be continuously forced against the screw head.
portion of the stem of the driver may in this case be made polygonal in
cross section to enable a firm hold to be obtained of it to allow of its
being turned like an ordinary screwdriver.
A
Provision may also be made for fastening the knob to the stem when-
ever desired, so that the screw driver may then be turned by the knob or
handle at its end.
The stem of the driver may also be suitably formed to have applied to
it whenever desired a ratchet and lever, by which it may be turned, or
other means may be adopted for turning the stem of the driver.
Figure 1 of the Drawings annexed shows a side view of part of the
stem of a screwdriver formed as hercin-before described, with a flat
circular end to bear upon the top of a screw head, and with a rib or it
might be ribs or projections upon it, to enter a cross cut or cuts or
recesses in the head of the screw.
Figure 2 shows an end view of the stem of the drivor.
Figures 3 and 4 show side views of a screwdriver with. the stem
formed in the manner above described, and with clips combined with it
to lay hold of the head of a screw and keep the screw head up to and
against the flat end of the driver; the screwdriver shown by these
Figures is adapted to be held in and driven by an ordinary centre bit,
but it may be formed in any other ordinary manner. The clip is
composed of a tube a capable of sliding to and fro upon the stem of the
screwdriver, and carrying four spring clips b, which tend to spring
outwards as shown at Figure 4. These springs lie in longitudinal slots

page_text: in the sliding tube. Upon the exterior of the tube a is a sliding collar e,
by shifting which endwise along the tube a the spring clips can be
forced inwards into the position shown at Figure 3. The stem of the
driver is of smaller diameter at its rear end than at the front, leaving a
shoulder at c; a screw collar d is screwed into the end of the sliding
tube a.
When a screw has been placed on to the end of the driver, the
tube a is pressed forwards until the ends of the spring clips ʊ come
beyond the head of the screw, the collar e is then pressed forwards,
thereby forcing inwards the spring clips and causing them to bear against
the sloping sides of the screw head in the manner shown at Figure 3.
By screwing inwards the screw collar d so as to cause its end to bear
against the shoulder c upon the stem of the driver, the sliding tube a
together with the clips which it carries can be drawn back, and the clips
be thereby held tightly up to and against the sloping sides of the screw
head. By this means the clips can be moved into position for properly
laying hold of and retaining the head of any screw. If desired a coiled
spring may be interposed between the shoulder on the stem and the
screw collar d, so as at all times to press back the sliding tube a. In
this case the spring clips would at once be drawn back away from the
screw head, whenever the sliding collar e is drawn back and the clips

page_text: The side view, Figure 7, shows the screwdriver with the clips 6 holding
the head of a screw up to and against the circular flat end of the stem.
Figure 8 shows a side view of the driver when the sliding collar e
has been drawn back, and the clips b allowed to spring outwards away
from the stem. The stem of the driver is shown to be formed at its end
with a cross bar handle, but other arrangements for turning the driver
may be adopted as before explained.
Having thus described the nature of my Invention, and the manner
of performing the same, I would have it understood that I claim,-
First. The construction of screwdrivers with circular ends to bear
against the heads of screws and with a rib or ribs or projections from
such circular end to enter corresponding recesses in the scrow heads.
Second. The combination of clips with such screwdrivers to hold the
heads of screws up to and against their circular ends.
Third. Mounting clips upon the stem of a screwdriver in such manner
that they can be moved backwards and forwards upon the stem.
Fourth. The construction of screwdrivers, substantially as hercin-
before described and shown in the Drawings annexed.
In witness whereof, I, the said William Knell, have hereunto set
my hand and seal, this Twenty-eighth day of June, in the year
of our Lord One thousand eight hundred and seventy-six.
WILLIAM KNELL. (L.S.)