Improvements in Breech Closing Mechanism for Ordnance.
Year: 1891

page_text: Date of Application, 4th July, 1891
Complete Specification Left, 2nd Apr., 1892-Accepted, 2nd July, 1892
PROVISIONAL SPECIFICATION.
Improvements in Breech Closing Mechanism for Ordnance.
I, AXEL WELIN, of the Scandinavian Sailors Temperance Home, Garford
Street, in the County of Middlesex, Mechanical Engineer & Honorary Manager of
the said Institution, do hereby declare the nature of this invention to be as
follows:-
This invention has for its object improvements in breech closing mechanism for
ordnance.
For the purpose of closing the breech of a gun it is usual to employ a breech
block with screw threads upon it to engage with corresponding screw threads
within the breech and sections of these screw threads are removed both from the
block and the breech so that a partial rotation of the block is sufficient to cause all
the thread to engage or to become disengaged.
In this arrangement however the locking segments cannot occupy more than
one half of the circumference and for the remainder there is no engagement between
the block and the breech; this requires by way of compensation that greater length
should be given to the threaded portion of the block than would otherwise be
required.
In order that the screw segments may be able to engage over more than half of
the circumference I arrange the segments in steps; thus for example one eighth
nearly of the circumference of the block may be occupied by one segment and the
next adjacent eighth by another segment but with this latter segment higher, or
further from the centre of the block, than the first segment. Then may follow a
third segment higher than the second segment. These three segments together
with a space without screw threads complete one half of the circumference, and the
other half is occupied by another similar series of steps and another space.
this arrangement it will be seen that the block is locked to the breech around
nearly three quarters of the circumference and that one eighth of a turn suffices
either in locking or unlocking.
With
In unlocking the lowest step on the block is brought to the position previously
occupied by the middle step but as it is not high enough it does not engage with
the screw threads in the breech which are then opposite to it. In like manner the
middle step on the block comes to the position previously occupied by the highest
step; whilst in turn the highest section goes into the vacant segment where there
are no threads within the breech of the gun. According to another arrangement I
may provide but one series of steps, say three steps occupying three quarters of the
circumference leaving one quarter for the void space; in this case a quarter turn
of the breech block will be required in locking and unlocking.
It is not necessary that the sides of the segments and of the void spaces should
be parallel to the axis of the gun on the contrary I prefer that they should be
spirally arranged for the purpose of equalising the strains all around the breech.
Dated this 4th day of July 1891.

page_text: COMPLETE SPECIFICATION.
Improvements in Breech Closing Mechanism for Ordnance.
I, AXEL WELIN, of the Scandinavian Sailors Temperance Home, Garford
Street, in the County of Middlesex, Mechanical Engineer & Honorary Manager of
the said Institution, 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 improvements in breech closing mechanism.
For the purpose of closing the breech of a gun it is usual to employ a breech
block with screw threads upon it to engage with corresponding screw threads
within the breech and sections of these screw threads are removed both from the
block and the breech so that a partial rotation of the block is sufficient to cause all
the thread to engage or to become disengaged.
In this arrangement however the locking segments cannot occupy more than
one half of the circumference and for the remainder there is no engagement
between the block and the breech; this requires by way of compensation that
greater length should be given to the threaded portion of the block than would
otherwise be required.
In order that the screw segments may be able to engage over more than half of
the circumference I arrange the segments in steps; thus for example one eighth
nearly of the circumference of the block may be occupied by one segment and the
next adjacent cighth by another segment but with this latter segment higher, or
further from the centre of the block, than the first segment. Then may follow a
third segment higher than the second segment. These three segments together
with a space without screw threads complete one half of the circumference, and
the other half is occupied by another similar series of steps and another space. With
this arrangement it will be seen that the block is locked to the breech around
nearly three quarters of the circumference and that one eighth of a turn suffices
either in locking or unlocking.
In unlocking the lowest step on the block is brought to the position previously
occupied by the middle step but as it is not high enough it does not engage with
the screw threads in the breech which are then opposite to it. In like manner the
middle step on the block comes to the position previously occupied by the highest
step whilst in turn the highest section goes into the vacant segment where there
are no threads within the breech of the gun. According to another arrangement I
may provide but one series of steps, say three steps occupying three quarters of
the circumference leaving one quarter for the void space; in this case a quarter
turn of the breech block will be required in locking and unlocking,
It is not necessary that the sides of the segments and of the void spaces should
be parallel to the axis of the gun; on the contrary I prefer that they should be
spirally arranged for the purpose of equalising the strains all around the breech.
In order that my said invention may be fully understood and readily carried into
effect I will proceed to describe the drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
my
Figure, 1 is a side elevation of a breech block in accordance with invention.
Figure 2 is a front elevation of the same.
Figure 3 is also a front elevation and shews a modification.
Figure 4 is a diagram illustrating another modification.
In Figures 1 and 2, a a are two similar segments or groups of screw threads on
the periphery of the block and on opposite sides of it. b and c c are also pairs of
similar segments. d d are spaces where there are no screw threads. Each segment
occupies about one eighth of the circumference of the block.

page_text: The screw threads at a a are of smaller radius or nearer to the centre of the
block than the screw threads at bb; similarly the screw threads at b b are nearer
to the centre than those at c c.
The breech of the gun has corresponding segments of screw threads within it.
When the breech block is turned in the breech of the gun through an arc of
45 degrees the screw threads at a assume the position previously occupied by the
screw threads at b but being on a smaller diameter do not engage with the threads
within the breech of the gun. Similarly the screw threads at 6 pass to the position
previously occupied by the screw threads at c and likewise do not engage.
At the same time the screw threads at c pass to the blank segment in the breech
of the gun. The breech block may then be drawn rearwards out of the gun.
Similarly when the breech block is replaced, a rotation through an arc of 45 degrees
locks it securely.
In Figure 3 the segments a b c and d are similarly arranged but not in pairs; in
this case a quarter rotation is required for locking and unlocking.
The threads upon the segments a band c may be of any pitch desired either
smaller or larger than that shewn by the drawings.
Figure 4 shows the developed cylinder either of the breech block or of the
interior of the gun; in this case it will be seen that the segments a b c d are not
parallel to the axis of the gun but obliquely arranged, in this way the strain upon
the gun and the breech block may be distributed all around the periphery.
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. A breech block closing the breech of a gun and locking in the gun by means
of a divided screw, and having the segments of the said divided screw arranged
around the circumference of the block in steps at different distances from the
centre or axis of the block.
2. A breech block in accordance with the preceding claim and with the segments
of the divided screw obliquely arranged.
Dated this 10th 1
1000