Year: 1887

page_text: Date of Application, 30th Apr., 1887
Complete Left, 30th Jan., 1888
Complete Accepted, 2nd Mar., 1888
I, JOHN ARDEN BIRCH, of 1 Queens Gate Terrace in the County of Middlesex,
Gentleman, do hereby declare the nature of this invention to be as follows:-
According to this invention I construct anchors in such a way that the arms and
flukes can be turned back so as to free the anchors when they cannot be lifted owing
to sticking in the bottom.
•
For this purpose I pivot the arms to the shank but normally prevent then from
turning so that the anchor acts in exactly the same way as an ordinary anchor.
If however the anchor sticks the arms can be released and allowed to turn and free
themselves.
A convenient manner of doing this is to make the lower part of the shank of the
anchor hollow and to have inside it two levers pivotted near its end which are prevented
from separating beyond a certain distance from each other by the sides of the shank
and are prevented from approaching each other by a key introduced between them.
This key is connected to a line led to the surface, by which it can be withdrawn so as
to allow the upper ends of the two levers to approach each other. The lower ends
of the levers enter notches in the axes of the arms, and when their other ends
approach each other they lift out of these notches and thereby leave the arms free
to turn.
The arms of the anchor can also be similarly turned down towards the shank for
convenience in stowing.

page_text: I, JOHN ARDEN BIRCH, of 1 Queens Gate Terrace, in the County of Middlesex,
Gentleman, do hereby declare the nature of this invention and in what manner the same
is to be perormed to be particularly described and ascertained in and by the
following statement:—
According to this invention I construct anchors in such a way that the arms and
flukes can be turned back so as to free the anchors when they cannot be lifted owing
to sticking in the bottom.
For this purpose I pivot the arms to the shank but normally prevent them from
turning so that the anchor acts in exactly the same way as an ordinary anchor.
If however the anchor sticks the arms can be released and allowed to turn and free
themselves.
A convenient manner of doing this is to make the lower part of the shank of the
anchor hollow and to have inside it two levers pivoted near its end which are
prevented from separating beyond a certain distance from each other by the sides
of the shank and are prevented from approaching each other by a key introduced
between them. This key is connected to a line led to the surface, by which it
can be withdrawn so as to allow the upper ends of the two levers to approach each
other. The lower ends of the levers enter notches in the axes of the arms, and when
their other ends approach each other they lift out of these notches and thereby leave
the arms free to turn.
The arms of the anchor can also be similarly turned down towards the shank
for convenience in stowing.
In order that my said invention may be more fully understood and readily carried
into effect I will proceed to describe the drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a side elevation of an anchor constructed according to my invention.
Figure 2 is also a side elevation the cover plate being removed.
In both these figures the arms are in their normal position.
Figure 3 is a side elevation the cover plate being removed, and
Figure 4 is a longitudinal section.
In the two last mentioned figures the arms are turned down.
a is the shank of the anchor, bb are the arms; they are pivotted at b¹ bl. с с аге
two levers pivoted at c¹ c¹ their lower ends are provided with projections which enter
the notches b* 6 of the axes of the arms, as shewn in figure 2. The other ends
of the levers c c are separated by the wedge d as shown in figure 2, and so long
as the wedge remains between them, they hold the arms of the anchor in position,
but when the wedge d is withdrawn as shewn in figure 3 the upper ends of the
levers c c come together leaving the arms 6 b free to assume the position shewn

page_text: in figures 3 and 4. The wedge
is held down by a spring d' and it carries an eye d
to which a line to the surface is attached.
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. An anchor having pivoted arms which are so held that they can be freed
by means of a connection to the surface and allowed to turn substantially as
described.
2. The combination of the arms b, the levers c and the wedge & substantially
as described.