Improvements in Screw Bolts and Lock Nuts, applicable also to Wood Screws.
Year: 1892

page_text: Date of Application, 25th Nov., 1892
Complete Specification Left, 24th Aug., 1893-Accepted, 30th Sept., 1893
PROVISIONAL SPECIFICATION.
Improvements in Screw Bolts and Lock Nuts, applicable also to
Wood Screws.
We JOHN MAGINN of Sankey Street Warrington Coach Proprietor and
FELIX MAGINN of 2 Great Clowes Street Broughton Mechanic both in the
County of Lancaster, do hereby declare the nature of this invention to be as
follows:-
Our improvements in screw bolts and lock nuts are intended principally to be
used in cases where it is desired to affix a metal plate onto a metal frame, but they
are also applicable in other cases where a perfectly safe, screw bolt, either with or
without a lock nut is required.
The invention is also applicable to wood screws to be used under similar
circumstances.
In making a screw bolt (say for example) for fixing a half inch plate onto a
metal frame (say) two inches thick we make the shank or body of the bolt of two
different diameters say five eighths of an inch diameter for about an inch and
three quarters from the end, and the remainder about three quarters of an inch
diameter.
We then chase the smaller diameter with an ordinary right hand thread, and we
reduce the upper part of the bolt half an inch from the head into a plain neck
about five eighths of an inch diameter without any screw thread. On the inter-
mediate part (which will be about a quarter of an inch long) we chase a left hand
thread preferably the same number of threads to. the inch as on the smaller
diameter.
We tap corresponding screwed holes in the plate and the frame, the former
left handed to fit the larger short screwed part of the bolt, and the latter right
handed to fit the smaller and longer screwed part of the bolt, and we countersink
the hole in the frame for about a quarter of an inch from the surface to a larger
diameter than the largest screw.
To fix the plate to the frame the bolts must first be all passed through the holes
in the plate and turned to the left hand until the left hand screwed portion has
screwed its way completely through the plate and the plain cylindrical neck will
then turn free in the screwed hole in the plate.
The plate (with the screws thus in place) is then applied to the frame and the
screws being all turned simultaneously to the right will screw their way into the
holes in the frame and draw the plate firmly down thereto, and it will be evident
that these screws cannot by any means work loose by themselves as one cannot rise
without the others.
To withdraw these screws they must all be turned simultaneously to the left and
the plate must at the same time be raised gradually by means of wedges or similar
means. It will of course be understood that it is not absolutely necessary to have
a separate man to each screw but that if one man only is employed he must not
make more than about one half turn at a time upon each screw so that they will all
rise equally together.
When the plate is removed the screws may be left therein ready for replacement
or if it is desired to remove them they must be pressed outwards and turned to the
right hand.
It will be readily understood that wood screws for use under similar circumstances
can be made on precisely the same principle.
When it is desired to use a lock-nut with a screw bolt of the above description
we make the body or shaft of the bolt plain, and we reduce the diameter at the end

page_text: for a certain length (say for example one inch) leaving a shoulder and this part
from the shoulder outwards we chase with a left handed screw thread, and we also
chase a portion of the body of the bolt (from the shoulder towards the head)
with a right handed screw thread preferably having the same number of threads to
the inch.
The locknut which we employ with a bolt of this construction is a double one,
that is to say, two nuts are made, one of which corresponds with and fits on the
small left hand screw, and the other corresponds with and fits on the larger right
hand screw on the body of the bolt. One of these nuts is made with a neck and
the other with a collar and they are pressed, rivetted, or otherwise attached to each
other in such a way that they cannot be separated longitudinally but can turn freely
and independently of each other, thus forming a compound locknut. It will be
obvious that a compound locknut of this description can readily be applied to a
screw bolt formed as last above described, and that upon using two keys or spanners
and turning the two portions of the lock nut simultaneously in opposite directions it
can be screwed on until it becomes "jammed" when the lock nut will be perfectly
secure and can only be loosened by means of two keys or spanners turned
simultaneously in opposite directions.
It will be evident that this principle of reversed screw and compound locknut
will be applicable to what are known as "patent axles" for carriages and for other
analogous purposes where a perfectly secure lock-nut is desirable.
Dated this 24th day of November 1892.
GEO. DAVIES & SON,
4, St. Ann's Square, Manchester, Agents for the Applicants.
COMPLETE SPECIFICATION.
.
Improvements in Screw Bolts and Lock Nuts, applicable also to
Wood Screws.
We JOHN MAGINN of Sankey Street Warrington Coach Proprietor, and
FELIX MAGINN of 2 Great Clowes Street Broughton Mechanic, both in the
County of Lancaster, 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 :-
Our improvements in screw bolts and lock-nuts are intended principally to be
used in cases where it is desired to affix a metal plate onto a metal frame, but they
are also applicable in other cases where a perfectly safe screw bolt either with or
without a lock-nut is required.
The invention is also applicable to wood-screws to be used under similar
circumstances.
The nature of our said invention and the manner in which the same is to be
performed or carried into practical effect will be readily understood on reference to
the sheet of illustrative drawings hereunto annexed and the following explanation
thereof.
Figs. 1 to 12 (inclusive) on the annexed drawing illustrate various methods of
carrying out our invention but we wish it to be understood that other similar plans
possessing the same distinctive features of our invention might be adopted, without
departing from the novel principle hereinafter described.
In making a screw bolt (say for example) for fixing a half inch plate onto a
metal frame (say) an inch and a half or more in thickness we make the shank or
body of the bolt (see Fig. 10) of two different diameters (say) one quarter of an inch
for about one inch and an eighth from the end, and the remainder about three eighths
of an inch diameter. We then chase the smaller diameter a with an ordinary right
hand thread, and we reduce the upper part of the bolt half an inch from the
head into a plain neck about one quarter of an inch in diameter without any screw
thread.

page_text: On the intermediate part c, which is about three eighths of an inch long, we
chase a left hand thread preferably the same number of threads to the inch as on
the smaller diameter a.
We tap corresponding screwed holes into the plate and the frame, the former
left handed to fit the larger short screwed part c of the bolt, and the latter right
handed to fit the smaller and longer screwed part a of the bolt, and we countersink
the hole in the frame for about three eighths of an inch from the surface to a larger
diameter than the larger screw c.
To fix the plate to the frame the bolts must first be all passed through the holes
in the plate and then turned to the left hand until the left hand screwed portion c
has screwed its way completely through the plate and the plain cylindrical neck b
will then turn free in the screwed hole in the plate.
The plate (with the screws thus in place) is then applied to the frame, and the
screws being all turned simultaneously to the right hand will screw their way into
the holes of the frame and draw the plate firmly down thereto, and it will be
evident that these screws cannot by any means work loose by themselves, as one
screw cannot possibly rise without the others.
To withdraw these screws they must be all turned simultaneously to the left,
and the plate must be at the same time raised gradually by means of wedges or a
similar device. It will of course be understood that it is not absolutely necessary
to have a separate man to each screw but that if one man only is employed he
must not make more than about half a turn at a time upon each screw so that
practically they will all rise equally together.
When the plate is removed the screws may be left therein ready for replacement,
or if it is desired to remove them they must be pressed ontwards and turned to the
right hand.
It will be readily understood that wood screws for use under similar circumstances
can be made on precisely the same principle as shown at Fig. 11.
When it is desired to use a lock-nut with a screw bolt of the above description
we make the body or shaft of the bolt as shown at d (Fig. 1) and we reduce the
diameter at the end for a certain length (say for example one inch and a quarter)
as shown at e leaving a shoulder, and this part e from the shoulder outwards we
chase with a right handed screw thread as shown, and we also chase a portion of
the body of the bolt (from the shoulder towards the head) with a left handed
screw thread, preferably having the same number of threads to the inch, or if
preferred the smaller screw may be left handed and the larger screw right
handed.
The lock-nut which we employ with a bolt of this construction is a double one,
that is to say two nuts are made one of which corresponds with and fits on the
small right hand screw e and the other corresponds with and fits on the left hand
screw thread on the body of the bolt. One of these nuts is made with a neck
or collar and secured to the other with two or more pins (as shown in section
at Fig. 12) or they are pressed, rivetted, or otherwise attached to each other in
such a way that they cannot be separated longitudinally but can turn freely and
independently of each other, thus forming a compound lock nut.
It will be obvious that a compound lock nut of this description can be readily
applied to a screw bolt formed as shown at Fig. 1 and above described, and that by
using two keys or spanners and turning the two portions of the lock nut
simultaneously in opposite directions it can be screwed on until it becomes
"jammed" when the lock nut will be perfectly secure and can only be loosened by
means of two keys or spanners turned simultaneously in opposite directions.
In some cases we propose to make the two portions of the lock nut detachable
when off the bolt, one part heing provided with a groove or recess 9 at one side
(sec side and face views Fig. 2) and the other with a T-headed projection h
flattened at both sides (see Fig. 3) so that the two can be slidden together as seen
at Fig. 4 so as to connect them together but still to allow them to be turned
separately.

page_text: Figs. 5 and 6 show a slight variation of Figs. 2 and 3 the edges of the locking
parts being bevilled off. Figs. 7 and 8 show the detached parts of another
modification wherein the groove or recess g extends across the whole face of one
portion and the locking piece h on the other portion is circular.
Fig. 9 shews the two parts united.
It will be seen that in any of these modifications the two portions are readily
separable sideways when off the bolt, but will be held firmly together when in
place on the bolt.
€6
It will also be evident that the above described principle of reversed screws and
compound lock-nut will be applicable to what are known as patent axles" for
carriages and for other analogous purposes whereby a perfectly secure lock nut is
desirable.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
First. A screw bolt or screw of two diameters one chased with a right hand and
the other with a left hand screw thread and having a plain neck between the two
screws and the head, and
Secondly. The combination with a screw or screw bolt chased partly with a
right hand and partly with a left hand screw thread, of a compound lock nut
composed of two parts so connected together that when upon the bolt they
cannot be separated endwise, but are capable of being turned independently of
each other one part being chased internally with a right hand and the other part
with a left hand screw thread to correspond with the screw threads on the bolt,
substantially as hereinbefore described and illustrated by the drawings hereunto
annexed.
Dated this 23rd day of August. 1893.
GEO. DAVIES & SON,
4, St. Ann's Square, Manchester, Agents for the Applicants.