Improvements in Screws.
Year: 1893

page_text: Date of Application, 20th Oct., 1893
Complete Specification Left, 7th Feb., 1894-Accepted, 17th Mar.,
1894
PROVISIONAL SPECIFICATION.
Improvements in Screws.
I, ROSA RESTALL, of 101 Marylebone Road, London, W., no occupation, do
hereby declare the nature of this invention to be as follows:-
The object of my invention is to provide a screw which will readily enter wood
without the necessity of first boring a hole therefore; and secondly, to make the
screws in such manner that the wood displaced by the screw is removed.
or,
By this my invention, I form the point of the screw in the form of a boring-bit ;
I may make the point angular and pointed. By thus pointing the screws I am
enabled to insert them in the wood without first making a hole therefore.
The shank or plain portion of the screw is reduced in diameter, and in some
cases I make a spiral or straight groove around it. By thus reducing the diameter
of the shank the displaced wood can readily escape, and moreover, the screw will
more readily enter the wood. In order to keep the clearance open and facilitate
the exit of the displaced wood, I form a small projection at right angles to the
shank.
Doted this 20th dor of October 1893
ROSA RESTALL.
COMPLETE SPECIFICATION.
Improvements in Screws.
I, ROSA RESTALL, of 101 Marylebone Road, London, W., in the County of
Middlesex, no occupation, 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 :-
This my invention has reference to certain new and useful improvements in that
class of screw used for woodwork; but more particularly to screws having a groove
extending along their length intended to permit the escape of the wood displaced
by the screw.
Screws of this class as heretofore manufactured, consist of an ordinary screw
having a spiral or straight groove extending throughout their length and gimlet-
pointed. Now it has been found in practice, that screws thus pointed compress and
force their way into the wood without cutting their way and removing the displaced
material which is merely compressed to accommodate the screw; the groove therein
being practically useless.
Now by this my invention, a screw is produced whereby the aforementioned
objections are overcome, and which screw, moreover, will enter the hardest of woods
without boring a hole therefor: and which will cut out aud remove the displaced
wood or other material.
The head of a screw constructed in accordance with this invention, is rendered
capable of countersinking itself without compressing and possibly splitting the
wood.
I now proceed to describe my said invention, reference being had to the accom-
panying drawings, and to the figures and letters of reference marked thereon; like
letters referring to like parts throughout.
Fig. 1. shews my improved screw having a spiral groove;
Kio 2 shows the screw having a straight groove; and

page_text: Fig. 3 shews another form of the screw having means which render the head
capable of countersinking itself, and the screw to clear its way into the wood.
In Fig. 1., the screw A is formed with a point a, resembling that of the ordinary
and well-known " spoon bit"; and has also a spiral groove which extends
throughout its length and the head c.
Fig. 2., illustrates a screw having a cutting-point the same as that shewn in
Fig. 1., but having a straight groove.
It is well known that when two pieces of wood or the like are to be screwed
together, that the hole in one piece, namely that which receives the shank d,
should be of larger diameter than the outside edge of the thread. Now, in order
to provide for this, 1 either make the shank d (Fig. 3.) of the same diameter as
the bottom e of the thread, or I may form one or more sharp-edged projections fto
the shank d to cut away the sides of the hole as the screw enters. If desired, the
projections may extend the whole length of the shank and form part of the
sharp-edged projection g, as indicated by the broken lines h.
The sharp-edged projection or projections 9 serves to remove the wood around
the head c and enable it to countersink itself.
Although I have described my invention as pertaining to the form of screw
illustrated in the drawings yet it will be understood that the invention is applicable
to some other kinds of screws or articles having screw shanks, such for instance, as
screw-hooks, screw-rings, screw-eyes, screw-attachments and such like articles.
Moreover, although I have illustrated screws having cutting points as shewn,
yet I may provide screws with any kind of point which actually cuts through the
wood and does not force its way therein by compressing it. Such an alternative
form of point is indicated in Fig. 3, and has sharp cutting edges a¹.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is : --
1. In a screw having a spiral or straight groove extending along its length, said
screw formed with a bit-shaped or other cutting point,-not being a "gimlet"
point, and said point adapted to cut away and remove the wood or other material,
substantially as and for the purpose hereinbefore set forth.
2. A screw having its shank or plain portion reduced in diameter, substantially as
and for the purpose herein before set forth.
3. A screw having one or more sharp-edged projections extending from the
shank or plain portion thereof, substantially as and for the purpose herein set
forth.
4. A screw having a sharp-edged projection or projections extending from the
underside of the head thereof, substantially as and for the purpose hereinbefore
set forth.
5. A screw-hook, screw-eye or such like screw-attachment formed with a straight
or spiral groove along the screw-shank, and having a bit-shaped or other cutting-
edged point, substantially as herein before set forth.
Dated this 7th day of February 1894.