Improvements in Wood Screws.
Year: 1893

page_text: Date of Application, 21st Mar., 1893
Complete Specification Left, 23rd Nov., 1893-Accepted, 10th Mar., 1894
Improvements in Wood Screws.
I, JAMES FRY, of 39 Front Street, Tynemouth, in the County of Northumberland,
Diver, do hereby declare the nature of this invention to be as follows:-
My invention relates to certain improvements in the construction of wood screws,
especially such as are used where the nature of the wood and character of the
work causes a great risk either of unduly straining or even splitting the wood,
such improvements greatly facilitating the insertion and screwing home of the
screws with less application of force.
"
In wood screws as now made, the neck, between the head and the screwed part
is parallel, the bottom of the thread only, tapering to the point, and a "gimlit'
or "bradawl" bores a hole for the insertion of the screw, only of the diameter of
this part, the threads of the screw completing the operation by cutting into the
solid wood and when the parallel neck enters, as the screw is screwed home, it
has to force its way by enlarging the hole made by the "gimlet," unless the hole
at this part is enlarged by using a larger tool to bore or "rimer out the hole to
receive the parallel neck which involves a great loss of time, and thus the wood,
especially in fine cabinet and similar work is split.
"
According to my invention I form the neck of the screw tapering from under
the head to about the diameter of the bottom of the thread next the neck, and
thence to the point, and in addition I propose to cut, or otherwise form, along
the screw from under the head to about the point a groove (or grooves) with sharp
edges, like a "master-tap," to further facilitate, the screwing home without straining
or splitting the wood. The effect of the tapered neck is to act as a "rimer
gradually enlarging the hole to admit it, without straining the wood to any serious
extent, and the action of the groove (or grooves), by causing the tapered neck to
cut its way, prevents any straining whatever.
Dated this 21st day of March 1893.
T. J. DANSON,
By L. W., per F. B.
COMPLETE SPECIFICATION.
Improvements in Wood Screws.
JAMES FRY 39 Front Street Tynemouth in the County of Northumberland
Diver, 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 :-
My invention relates to certain improvements in the construction of wood screws
especially such as are used where the nature of the wood and character of the
work causes a great risk either of unduly straining or even splitting the wood,
such improvements greatly facilitating the insertion and screwing home of the
screws with less application of force.
In wood screws as now made, the neck, between the head and the screwed part is
parallel the bottom of the thread only tapering to the point, and a "gimlet" or
"bradawl" bores a hole for the insertion of the screw, only of the diameter of this
part, the threads of the screw completing the operation by cutting into the solid
wood and when the parallel neck enters, as the screw is screwed "home," it has
D71

page_text: to force its way by enlarging the hole made by the "gimlet "-unless the hole at
this part is enlarged by using a larger tool to bore
"
" rimer
or
out the hole to
receive the parallel neck, which involves a great loss of time, and thus the wood,
especially in fine cabinet work is split.
:
According to my invention I form the neck of the screw tapering from under
the head to about the diameter of the bottom of the thread next the neck and
preferably thence to the point, and in addition I propose to cut, or otherwise form,
along the screw from under the head towards the point a groove (or grooves)
with sharp edges like a master tap," to further facilitate, the screwing home
without straining or splitting the wood.
66
DESCRIPTION OF DRAWINGS.
On the accompanying sheet of drawings I illustrate my invention by comparison
with wood screws as now ordinarily used and to facilitate such comparison the
screws are shewn to a considerably increased size.
Figs. 1 and 2 shew an ordinary wood screw, in two stages of its insertion viz.
by Fig. 1 when the threaded part has been screwed through on piece of wood and
Fig. 2 when it is screwed "home." In this screw the neck A is of the same
diameter as the top of thread and parallel, the thread B also being parallel,
though in some screws it is tapered. It will be seen that after the thread has
worked through the piece of wood C, which is to be screwed to the main piece D,
it has left in C a female thread which the neck A has to crush out as the thread is
-screwed "home," as in Fig. 2, and this causes a strain on the piece C very likely
to split it.
Figs 3 and 4 shew my improved screw, in the same relative positions, the
neck A tapering from under the head to about the diameter of bottom of thread
which is not shewn tapered.
Figs. 5 and 6 shew my screw with the taper of the neck continued to the point
and the threaded part also tapered. One groove E only is shown running out
so far down the threaded part but two or more may be used without unduly
'weakening the screw.
The effect of the groove, or grooves, is to cut away the threads of the female
screw in C which have been left by the male threads and to facilitate the entry
of the tapered neck without straining or splitting the wood. Even with the
ordinary screw with parallel neck such a groove, (or grooves) cut in it, the
passage of the neck is much easier, as instead of crushing it out the female thread
is cut out, but the tapered neck is much preferable.
Having now particularly described and ascertained the nature of said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1st. The improvement in wood screws consisting in forming the neck tapering,
from under the head to the commencement of the thread, to facilitate the screwing
"home
of the screw without straining or splitting the wood, by gradually
enlarging the hole left by the thread substantially as described and shewn.
"
2nd. In wood screws with such tapered necks, or in ordinary wood screws with
parallel necks, the improvement consisting in forming in the neck a groove, or
grooves, extending from under the head toward the point, to cause the neck to cut
its way through the hole left by the thread and so prevent straining, or splitting
the wood substantially as described and in one form shewn.
Dated this 22nd day of November 1002
T. J. DANSON, F. Inst. P.A.,
Chartered Patent Agent,
Newcastle-upon-Tyne, Agent for Applicant.
T. J. DANSON, F. Inst. P.A.,
Chartered Patent Agent,
Newcastle-upon-Tyne, Agent for Applicant.