Improvements in Trunnion Bearings for Ordnance and in Bearings to Carry the Axes or Trunnions of other Heavy.
Year: 1886

page_text: Date of Application, 27th Sept., 1886.
Complete Left, 23rd June, 1887.
Complete Accepted, 26th July, 1887.
Improvements in Trunnion Bearings for Ordnance and in Bearings
to Carry the Axes or Trunnions of other Heavy. Mechanism.
I RALPH THEW BRANKSTON of Elswick Works Newcastle on Tyne Engineer do
hereby declare the nature of this invention to be as follows:-
The improvements relate to means for reducing friction at the bearings of gun
trunnions and at the same time keeping the trunnion solidly supported on the bearing.
Like arrangements are applicable in mounting the axes or trunnions of other heavy
mechanism. In the case of a gun I cause the trunnion to be supported independently
of the bearing relieving the bearing of the greater part of the weight so that it may
move easily to give the requisite elevation whilst the bearing as usual sustains the
shock of the recoil.
To do this I sometimes provide a rocking pillar to bear against the underside of the
gun trunnion and this is pressed up against it by means of a spring bar which is fitted
to receive the small lower end of the rocking pillar. The amount of weight taken on
the rocking pillar is regulated by means of an adjusting screw which is screwed up
until nearly the whole weight of the gun is taken on the rocking pillar the gun
trunnion being still left touching its bearing in the mounting. Nearly the whole of
the friction of the trunnion is then taken at the bearing of the rocking pillar on the
spring bar and is acting at a very small radius, consequently the power required to
move the gun is very much reduced while the trunnion retains the whole of its
bearing to take the blow of recoil.
Sometimes to support the trunnion I provide a small auxiliary trunnion or pin
driven into the trunnion proper this auxiliary trunnion or pin being strong enough
to support the strain due only to the weight of the gun. The auxiliary trunnion is
received into an auxiliary bearing block. Underneath this is fitted a spring adjusted
so that its strength is nearly sufficient to lift the gun off the main trunnion. The

page_text: friction is then acting at the radius of the small trunnion and consequently the power
required to move the gun is very much reduced while the large trunnion is still
available to take the blow of recoil.
In place of providing a bearing for the auxiliary truunion or pin driven into the
trunnion proper, this auxiliary trunnion or pin may be supported on the surface of a
roller. On the roller is an axis working in a bearing in a spring bar and beneath the
spring bar is an adjusting screw by which the spring bar can be adjusted until nearly
the whole weight of the gun is taken on the roller. The gun trunnion being still left
touching its bearing in the mounting, nearly the whole of the friction of the trunnion
is taken on the axis of the roller and is acting through a reduced angle at a small
radius consequently the power required to move the gun is very much reduced while
the trunnion retains the whole of its bearing to take the blow of recoil.
When as in the case of a gun the angular motion required is small in place of
having a small auxiliary trunnion I can provide a bearing surface on the trunnion
which is not cylindrical in-form; it may be a plain-surface thus the lower half of the
trunnion may be cut away leaving a projecting piece to take a bearing on a knife
edge on a spring bar beneath. Adjusting pieces can be fitted beneath the spring bar
and their height adjusted so that when the gun is lowered into its place nearly its
whole weight is taken on the spring bar but the trunnion is still touching its own
bearing. The bulk of the friction is then acting at the radius of the knife edge and
the power required to move the gun is consequently very much reduced while the
large trunnion is still available to take the blow of recoil.
Or the upper part of trunnion itself may be cut in the form of a knife edge to rest
on the spring bar and this can be made adjustable by means of a screw.
These latter arrangements are particularly adapted for alteration of guns and
mountings already made.
Dated this 27th day of September 1886.
CARPMAEL & Co.,
Agents for the Applicant.

page_text: COMPLETE SPECIFICATION.
Improvements in Trunnion Bearings for Ordnance and in Bearings
to Carry the Axes or Trunnions of other Heavy Mechanism.
I, RALPH THEW BRANKSTON, of Elswick Works, Newcastle on Tyne, Engineer 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:
The improvements relate to means for reducing friction at the bearings of gun
trunnions and at the same time keeping the trunnion solidly supported in the bearing.
Like arrangements are applicable in mounting the axes or trunnions of other heavy
mechanism.
In the case of a gun I cause the trunnion to be supported independently of the
bearing relieving the bearing of the greater part of the weight so that it may move
easily to give the requisite elevation whilst the bearing as usual sustains the shock. of
the recoil.
To do this I sometimes provide a rocking pillar to bear against the underside of the
gun trunnion and this is pressed up against it by means of a spring bar which is fitted
to receive the small lower end of the rocking pillar. The amount of weight taken on
the rocking pillar is regulated by means of an adjusting screw which is screwed up
until nearly the whole weight of the gun is taken on the rocking pillar the gun
trunnion being still loft touching its bearing in the mounting. Nearly the whole of
the friction of the trunnion is then taken at the bearing of the rocking pillar on the
spring bar, and is acting at a very small radius, consequently the power required to
move the gun is very much reduced while the trunnion retains the whole of its
bearing to take the blow of recoil.
A trunnion bearing such as is described above is represented by the drawings
Figures 1 and 2.
Figure 1 is a side elevation.
Figure 2 is a section on the line X, Y, in Figure 1-in this figure the gun also is
shown.
A, A, are the trunnions resting in trunnion bearings B, B, forming part of a gun
carriage or mounting. B¹, B', are the compresser cylinders and C, C, the guides on
the slide along which the gun carriage traverses. A recess is made in the trunnion
bearing at D and in this recess the small rocking pillar E is lodged. At the ends of
this pillar cylindrical surfaces are formed; the upper end has the longer radius and
abats beneath the trunnion of the gun; the lower end is received into a corresponding
recess on the face of the spring bar F. This bar, at its forward end, rests upon a
fixed support G and its hinder end upon a screw H, which passes through a lug upon
the gun carriage. By turning this screw the rocking pillar is pressed upwards until
it supports the greater part of the weight of the gun. When this adjustment is made
it will be found that the gun will turn very readily about its trunnions, but never-

page_text: :
theless it is securely held to resist the shock of recoil as by an ordinary trunnion
bearing.
Sometimes to support the trunnion I provide a small auxiliary trunnion or pin
driven into the trunnion proper this auxiliary trunnion or pin being strong enough to
support the strain due only to the weight of the gun. The auxiliary trunnion is
received into an auxiliary bearing block. Underneath this is fitted a spring adjusted
so that its strength is nearly sufficient to lift the gun off the main trunnion. The
friction is then acting at the radius of the small trunnion and consequently the power
required to move the gun is very much reduced while the large trunnion is still
available to take the blow of recoil.
This arrangement is shown by the Figures 3 and 4. Figure 3 being a side
elevation of the bearing and carriage, and Figure 4 a section on the line X, Y, in
Figure 3. In Figure 4 the gun also is represented in place.
A, A, are the main trunnions of the gun and H, H, are the small auxiliary trunnions;
these are received. into bearing blocks I, I, which are lodged in guides provided to
receive them at the ends of the main bearings. K, K, are springs beneath the
auxiliary bearing blocks I, I; these springs are of sufficient strength almost but not
quite to lift the gun by its auxiliary trunnions.
In place of providing a bearing for the auxiliary trunnion or pin driven into the
trunnion proper, this auxiliary trunnion or pin may be supported on the surface of a
roller. On the roller is an axis working in a bearing in a spring bar and beneath the
spring bar is an adjusting screw by which the spring bar can be adjusted until nearly
the whole weight of the gun is taken on the roller. The gun trunnion being still left
touching its bearing in the mounting, nearly the whole of the friction of the trunnion
is taken on the axis of the roller and is acting through a reduced angle at a small
radius consequently the power required to move the gun is very much reduced while
the trunnion retains the whole of its bearing to take the blow of recoil.
Figures 5 and 6 illustrate this arrangement-they show respectively a side view
and section as before. J is the small auxiliary trunnion which in this case bears upon
the periphery of a wheel L, on the sides of this wheel are stud axes L', L', and these
rest in cavities upon the spring bar F which is adjustable by means of a screw H as
in Figures 1 and 2.
This method of mounting it will be observed is applicable where complete rotation
or rotation through a large arc is required; for this however in mounting guns there
is no necessity.
Where as in the case of a gun the angular motion required is small in place of
having a small auxiliary trunnion I can provide a bearing surface on the trunnion
which is not cylindrical in form;-it may be a plain surface, thus the lower half of
the trunnion may be cut away leaving a projecting piece to take a bearing on a knife
edge on a spring bar beneath. Adjusting pieces can be fitted beneath the spring bar
and their height adjusted so that when the gun is lowered into its place nearly its
whole weight is taken on the spring bar but the trunnion is still touching its own
bearing. The bulk of the friction is then acting at the radius of the knife edge and
the power required to move the gun is consequently very much reduced while the
large trunnion is still available to take the blow of recoil.
This arrangement is illustrated by the Figures 7 and 8 being respectively side view
and section as before. M is a bearing surface formed at the extremity of the main
trunnion A by cutting away the lower part down in the axial line. F is a spring bar
in the centre of which there is a projection terminating in a rounded nose or knife
edge. This knife edge should be in the axial line of the trunnions and should there
abut upon the surface M. The spring bar F is supported at its two ends and is
adjustable as before, either by a screw or by introducing filling pieces beneath it.
The adjustment is so made that the spring bars shall take almost the entire weight of
the guns. The arrangement on the two sides is similar.
Or the upper part of trunnion itself may be cut in the form of a knife edge to rest
on the spring bar and this can be made adjustable by means of a screw.

page_text: Figures 9 and 10 are respectively side view and section illustrating this arrange-
ment. O is the knife edge formed upon the trunnion of the gun. F is the supporting
spring bar and H the adjusting screw.
These latter arrangements are particularly adapted for alteration of guns and
mountings already made.
Having now particularly described and ascertained the nature of my said invention
and in what manner the same is to be performed I declare that what I claim is ;-
1. Trunnion bearings for ordnance provided with an auxiliary rocking, rolling, or
knife edge support substantially as described.
2. Providing auxiliary trunnions on the main trunnions and supporting these
trunnions in such manner as to relieve the main trunnion from the weight of the gun,
substantially as described.
3. The application of the said bearings provided as described with auxiliary
supports to carry the axes or trunnions of other heavy mechanism.
Dated this 17th day of June 1887
CARPMAEL & Co.,
Agents for the Applicant.