Improvements in or relating to Screws, Bolts, or the like.
Year: 1891

page_text: Date of Application, 28th May, 1891
Complete Specification Left, 26th Sept., 1891-Accepted, 31st Oct., 1891
PROVISIONAL SPECIFICATION.
Improvements in or relating to Screws, Bolts, or the like.
I, HENRY DAY, of 4, Beach Road, Weston-super-Mare in the County of
Somerset, do hereby declare the nature of this invention to be as follows:-
This invention has for its object certain improvements in screws and is designed
to enable the head of the screw to make its own countersink in the material and
thus enable the same to lie flush with, or below, the surface.
k
In carrying my invention into effect, I provide or form the under part of the
head of the screw with teeth or serrations somewhat similar to the tool used by
carpenters and joiners for chamfering or countersinking and sometimes known as a
rose bit." When the screw is screwed into the material, the serrations on the
under surface of the head cut away the material to form a countersink which
enables the head to sink into the material and lie flush with, or below, the surface
thereof.
By the use of this screw a considerable amount of time can be saved, as it
requires no more effort than that which is used to drive in any ordinary screw with
a screw driver.
The invention though more especially adapted to screws for wood may probably
be used with good results for the softer kinds of metal. It may also be applied to
bolts or the like.
Deted this 27th den of N 1801
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Patent Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in or relating to Screws, Bolts, or the like.
I, HENRY DAY, of Weston-super-Mare, in the County of Somerset, 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 invention has for its object certain improvements in screws and is designed
to enable the head of the screw to make its own countersink or depression in the
material and thus enable the same to lie flush with, or below, the surface.
cr
In carrying my invention into effect, I provide or form the under part of the
head of the screw with teeth or serrations somewhat similar to the tool used by
carpenters and joiners for chamfering or countersinking and sometimes known as a
rose bit." When the screw is screwed into the material, the serrations on the
under surface of the head cut away the material to form a countersink which
enables the head to sink into the material and lie flush with, or below, the surface
thereof.
Referring to the accompanying drawings—
Figure 1 is an elevation of the screw on a large scale in which a are the cutting
teeth or serrations by which the countersink is formed when the head is rotated.
Figure 2 is an inverted plan, and
Figure 3 is a cross section through the head.
I propose to make the head a trifle smaller than the head of an ordinary screw,
also the slit for the screw driver is a little wider and deeper in order to allow the
refuse matter from the screw borings coming to the surface.

page_text: My invention may be applied to certain other kinds of screw besides that shown,
the type shown on the drawing being merely illustrated by way of example.
By the use of my invention a considerable amount of time can be saved, as it
requires no more effort than that which is used to drive in any ordinary screw with
a screw driver.
The invention though more especially adapted to screws for wood may be used
with good results for the softer kinds of metal. It may also be applied to bolts or
the like.
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
The improvement in screws, bolts or the like which consists in forming the under
part or surface of the head with cutting teeth or serrations whereby the head when
rotated, is caused to form its own countersink or depression in the material, and
enable it to lie below or flush with the surface substantially as described.
Dated this 25th day of September 1891.
WM. P. THOMPSON & Co.,
Of Liverpool, Manchester, Nottingham, and London, Patent Agents.