An Improvement in Worm Gear for Training Guns.
Year: 1899

page_text: PROVISIONAL SPECIFICATION.
An Improvement in Worm Gear for Training Guns.
We, VICKERS SONS & MAXIM LIMITED, of River Don Works, Sheffield, in
the County of York, ARTHUR TREVOR DAWSON and GEORGE THOMAS BUCKHAM,
both of Vickers Sons & Maxim Limited, of 28, Victoria Street, Westminster,
in the County of London, do hereby declare the nature of this invention to be
as follows:-
The worm gear for training a gun is usually so arranged that if accident
should happen to it, the gun can no longer be trained. This invention relates
to an arrangement of the worm gear such that, in case of accident, the worm
can be removed, leaving the gun free to be trained by hand or otherwise. For
this purpose, we make the spindle of the worm in two parts the ends of which
meet in the middle of the worm, these ends and the bore of the worm are of
polygonal section or are provided with keys and grooves so that the spindles
can slide in the worm, which must turn with them. The other ends of the
spindles pass through the bosses of bevil wheels provided with keys and grooves
so that the spindles can slide through the wheels but must turn with them.
These ends are also screw threaded and provided with nuts outside the bevil
wheels. Usually one or other of the bevil wheels is worked by a bevil pinion
turned by hand and thus the worm is turned causing the worm wheel with which
it gears to turn, thus training the gun. But should the worm gear be injured
so that it cannot work, then by turning the nuts on the ends of the worm spindles,
these spindles are withdrawn out of the worm, leaving it free so that it can be
withdrawn from engagement with the worm wheel, and then the gun can be
trained by other means. The worm has its ends formed as journals working in
bearings in a frame which is fitted on the base of the mounting so that when the
spindles are withdrawn from the worm, and a catch released, the frame can be
drawn back moving the worm out of gear with the worm wheel.
Dated this 6th day of February 1899
ABEL & IMRAY,
Agents for the Applicants.
An Improvement in Worm Gear for Training Guns..
We, VICKERS SONS & MAXIM LIMITED, of River Don Works, Sheffield, in
the County of York, ARTHUR TREVOR DAWSON and GEORGE THOMAS BUCKHAM,
both of Vickers Sons & Maxim Limited, of 28, Victoria Street, Westminster,

page_text: in the County of London, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement: -
The worm gear for training a gun is usually so arranged that if accident
should happen to it, the gun can no longer be trained. This invention relates
to an arrangement of the worm gear such that, in case of accident, the worm
can be removed, leaving the gun free to be trained by hand or otherwise. For
this purpose we arrange the worm gear as we shall describe referring to the
accompanying drawings.
Fig. 1 is a part plan, Fig. 2 is a section on the line A A. of Fig. 1, Figs. 3
and shew details.
As shewn in Fig. 1 which represents the worm in the middle and the hand
worked spindle in its full length on the right hand side but broken off on the
left hand side, which is to be understood to be symmetrical with the right hand-
side, we make the spindle of the worm in two parts a a the ends of which meet
in the middle of the worm b, these ends and the bore of the worm are provided
with keys and grooves so that the spindles can slide in the worm, which must.
turn with them. The other ends of the spindles a a pass through the bosses of
bevil wheels c provided with keys and grooves so that the spindles can slide
through the wheels but must turn with them. These ends are also screw threaded
and provided with nuts & outside the bevil wheels c. Usually one or other of
the bevil wheels is worked by a bevil pinion e turned by hand and thus the worm
is turned causing the worm wheel with which it gears to turn.
The worm gears with a worm wheel f which is fixed on the vertical central
shaft of the gun mounting or the turret or turntable on which the gun is carried,
so that as either of the part spindles a or both are turned by hand, the gun is
trained. But should the worm gear be injured so that it cannot work, then by
turning the nuts d the spindles à a are withdrawn out of the worm, leaving it
free so that it can be withdrawn from engagement with the worm wheel, and
then the gun can be trained by other means.
In order to prevent the possibility of the shafts a screwing out through the
nuts during the normal working of the worm gear, owing to the nuts sticking
in their bearings, a pin o is driven through holes in the shaft and nut, so
as to secure the two together, such pin being removed when it is desired to
draw the shaft a out of the worm by the rotation of the nut d.
In the case where the spindle g, which is turned by hand, crosses in front of
the nut the spindle is made separable having a coupling of which Fig. 3
is a section so that by removing a screw the spindle can be drawn back
through the pinion e so as to give free access to the nut d.
The worm has its ends formed as journals working in bearings & in a frame 7
which is fitted on the base of the mounting so that when the spindles are with-
drawn from the worm and a catch screw nut released, the frame can be drawn
back moving the worm out of gear with the worm wheel.
The catch screw m of which Fig. 4 is a front view has a segment cut from one
side of its head so that when it is in one position as shewn in the drawing the
full part of its head bearing against the frame prevents it from being with-
drawn, but when the screw is turned half round bringing the cut off part to
the frame, then the frame can be drawn back bringing the worm 6 out of gear
with the worm wheel f and then on again turning the screw m half round, its
head becomes engaged in a notch n in the side of the frame and holds the
frame in its withdrawn position.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed we declare that what
we claim is:-

page_text: on the vertical training axis, a worm gearing with the wheel and mounted in a
horizontally sliding frame a spindle adapted to be worked by hand made in two
parts the ends of which meet in the middle of the worm, means of withdrawing
both spindles in opposite directions from the worm, leaving it free to be with-
drawn out of gear with the worm wheel, substantially as and for the purpose
set forth.
Dated this 20th day of Senterber 1899
ABEL & IMRAY,
Agents for the Applicants.