Improvements in Screw Bolts and Nuts and similar Connecting Devices.
Year: 1891

page_text: Date of Application, 10th Mar., 1891-Accepted, 11th Apr., 1891
COMPLETE SPECIFICATION.
Improvements in Screw Bolts and Nuts and similar Connecting
Devices.
I, CLINTON ALLEN HIGBEE, of 503, Market Street, in the City of Philadelphia,
State of Pennsylvania, United States of America, Salesman, do hereby declare
the nature of my 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 screw-coupling devices of which the screw-bolt and nut
are the most familiar examples but which include as well all threaded coupling
devices made up of two parts having respectively male and female screw-threads
such for instance as pipe couplings, lamp burner unions, axle points and nuts and in
short all fittings or parts adapted and formed to screw into each other by providing
them with male and female threads respectively. In threaded couplings of the
kind described the thread is usually turned in or on a cylindrical or annular part
prepared to receive it and at the end of said part the thread merges gradually in
its face which is usually in a plane at right angles to the centre of the thread; as a
result of this mode of construction the end of the thread is for some distance very
thin and by no means symmetrical to the centre line of the thread. As a result of
this mode of construction the two parts of the screw union can be and frequently
are put together wrongly not only cramping and binding the parts but breaking
and injuring the threads. Besides this the thin end of the thread is so situated as
to be most exposed to injury and having but little strength it is very apt to get
bent or broken.
My invention is intended to overcome the defects noted and consists in terminating
the thread below the face level of the cylinder or annulus on or in which it is
formed and forming the extreme end so that it will have a broad blunt face lying
symmetrically on each side of the centre line of the thread. By this construction
the ends of the threads are made strong, stout, and of substantially the same cross-
section as the thread itself and the two parts of the union are fitted together with
automatic precision so that there is the least possible risk of jamming or breaking
the thread. My invention will be better understood as described in connection
with the drawings in which I have illustrated it as applied to a bolt and nut and
in which,
Figure 1 shows a bolt and nut constructed in accordance with my invention, the
nut being shown both in face view and in dotted lines as applied to the bolt.
Figure 2 is an end view showing the bolt and nut screwed together, the bolt
projecting through the nut.
Figure 3 is a cross-sectional view of the nut.
Figure 4 is a view of a somewhat modified bolt with nut screwed upon it; and
Figures 5 and 6 show modified forms of thread ends.
A is the bolt; a its end; a' its thread; and a the thread-end. a³ (Fig. 1) a
cylindrical extension of the internal diameter of the nut thread between the
thread-end a² and the bolt end a. B is the nut; bits end or face; b¹ its thread ;
and 6 its thread-end; 6" a round extension of the threaded hole of substantially
the outer diameter of the bolt thread extending between the thread-end and the
end 6 of the nut. It will be noticed that the thread-end a' or 'lies below the
face or end a or b of the part in or on which it is formed; in Figure 4 its upper
edge is shown as just flush with said end and in Figure 1 the thread-end begins at
some little distance below the face a; by leaving the smooth extensions a³ or b³ as
shown the nut and bolt or their equivalents are brought together and properly
aligned before the thread-ends engage and thus an additional safeguard against
misadjustment is provided. The exact form of the thread-end is not very important

page_text: so long as it is blunt and substantially symmetrical with respect to the centre line
of the thread; it may be cut off on an oblique plane as in Figures 1, 2, 3 and 4;
or cut off square as in Figure 5; or rounded as in Figure 6.
•
I prefer and strongly recommend that both the male and female parts of my
screw coupling should be formed as I have shown and described; to attain the
full benefit of my invention this is necessary but improved results can also be
secured by using one screw-thread of usual construction with another having my
improvement and as I believe the device to be broadly new with me I desire to
protect by this Patent not only the complete coupling but a coupling having either
part provided with the improved construction of thread end. I desire it to be
clearly understood that my device is exclusively intended and adapted for screw
couplings or unions consisting of two parts each threaded to fit the other, and has
no reference to wood screws which are intended to force their way into yielding
substances.
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 :-
:
First In screw-bolts, nuts and equivalent threaded objects adapted for use in
screw couplings or unions as specified, a screw-thread having its end terminating in
a blunt broad face beneath the end or face of the part in or on which it is formed,
said end being symmetrically disposed or substantially so with respect to the line
of the centre of the thread substantially as shown and described and for the
purpose specified.
Second: In screw-threaded bolts and nuts and equivalent male and female
threaded objects adapted to screw together and form a screw-coupling or union,
threads having their ends terminating beneath the ends or faces of the threaded
parts of the coupling and each end symmetrically disposed or substantially so with
respect to the centre line of the threads all substantially as shown and described
and for the purpose specified.
Third: In screw bolts, nuts, and equivalent threaded objects adapted for use in
screw couplings as specified, a screw-thread having its end terminating in a blunt,
broad face symmetrically disposed with respect to the centre line of the thread,
and a cylindrical extension as a³ formed to fit neatly in the other member of the
coupling, said extension extending between the end of the thread and the face of
the threaded object, all substantially as and for the purpose set forth.
Dated this 10th day of March 1891
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.