Improvements in Derricks.
Year: 1898

page_text: PROVISIONAL SPECIFICATION,
Improvements in Derricks.
We, WALTER ERNEST HUTCHINSON, Mariner, of 55, Poets Road, Canonbury,
and ARTHUR EDWARD NEWTON, Mariner, of 16, Linthorpe Road, Stamford Hill,
both in the County of Middlesex, do hereby declare the nature of this invention
to be as follows; -
This invention relates to derricks such as are used on board ship for loading
or discharging cargoes, and has for its object to enable them to swing with
greater freedom in one direction of their traverse than in the opposite direction,
advantage being taken of this difference to facilitate the conveyance of the
load.
In a derrick constructed according to this invention and suitable for use on
board ship, the axis of rotation of the jib is capable of being inclined at any
angle in any desired direction, the plane of rotation of the derrick and its load
being thereby inclined also. The consequence of this obliquity. is, that when
rotating the jib through half a revolution the weight of the jib and load tends
to accelerate such rotation when the end of the jib is travelling from the highest
towards the lowest point in the said plane and thus reduce the force required
to turn the derrick when loaded, the opposite conditions obtaining when return-
ing the jib to its initial position with its outward end ascending the plane of
its rotation. In order to regulate the swing of the derrick the jib is connected
to the post or mast by means of an angle bracket provided with a number of
holes for the reception of pins which determine the position of the jib attach-
ment and the distance through which it is free to move and consequently the
angle of swing of the jib.
The swing of the jib is controlled by means of guys secured to it and passing
through guide pulleys and, if required, a compressor also, so as to be able to secure
the guys in any desired position.
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, Agents.

page_text: both in the County of Middlesex, 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 relates to derricks such as are used on board ship for loading
or discharging cargoes, and has for its object to enable them to swing with
greater freedom in one direction of their traverse than in the opposite direction,
advantage being taken of this difference to facilitate the conveyance of the
load.
In a derrick constructed according to this invention and suitable for use on
board ship, the axis of rotation of the jib is capable of being inclined at any
angle in any desired direction, the plane of rotation of the derrick and its load
being thereby inclined also. The consequence of this obliquity is, that when
rotating the jib through half a revolution the weight of the jib and load tends
to accelerate such rotation when the end of the jib is travelling from the highest
towards the lowest point in the said plane and thus reduce the force required
to turn the derrick when loaded, the opposite conditions obtaining when return-
ing the jib to its initial position with its outward end ascending the plane of
its rotation. In order to regulate the swing of the derrick the jib is connected
to the post or mast by means of an angle bracket provided with a number of
holes for the reception of pins which determine the position of the jib attach-
ment and the distance through which it is free to move and consequently the
angle of swing of the jib.
The swing of the jib is controlled by means of guys secured to it and passing
through guide pulleys and, if required, a compressor also, so as to be able to
secure the guys in any desired position.
In the accompanying sheets of drawings:
Fig. 1 is a side elevation of one arrangement of a ship's derrick constructed
according to this invention and specially adapted for loading and unloading
cargo on board ship.
Fig. 2 is a plan and
Fig. 3 a front elevation of the same.
Fig. 4 is a plan of a slightly modified arrangement of derrick.
Figs. 5 and 6 are front elevation and plan respectively of a pair of derricks
working on one mast or post.
Referring to Figs. 1, 2 and 3, the lower end of the leg a is connected to the
mast by means of the swivel pin c in the usual manner while the upper and
outer end of the same is connected by the back or span chain d to a block e
which embraces the bar g of a bracket a secured to the mast b the said block
being capable of being slid into any position thereon and secured in such position
by pins for otherwise.
for
It will be readily seen that by selecting a proper position on the bar
the block e any list of the ship may be neutralized and the jib a be caused to
automatically swing in the desired direction.
In the case of a rolling vessel the action of the jib a may be controlled by
guys secured to its outer end and passing through guide blocks and being
operated by means of a winch or capstan 1.
In the arrangement shown in Fig. 4 the guy rope h instead of being con-
nected to an operating winch is passed through a compressor m by means of
which it is firmly gripped, thereby holding the jib a in any desired position.
Figs. 5 and 6 show an arrangement of a pair of derricks placed side by side,
their back chains being secured to a common bracket o.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that
what we claim is:
1. In a ship's 'derrick, a bracket secured to a mast or post and having a

page_text: graduated bar or limb to which the back chain or span is secured in any desired
position substantially as and for the purpose set forth.
2. The combination of the jib a, guys h, winch or capstan / and bracket n for
securing the back chain & substantially as described with reference to Figs. 1, 2
and
of the drawings.
3. The combination with a derrick jib, of a mast or post bracket for securing.
the back chain in any desired position, guys for controlling the position of the
jib and a compressor for securing the guys, the whole substantially as described.
4. The arrangement and construction of derricks substantially as described
with reference to the drawings.
Dotal this 10th day of V.... 1000
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.