February 19, < 1915.

THE COLLIERY GUARDIAN.

383

Headgear Legs.

Level

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— Section thro' L of Pit —

— Looking Towards Full Side. —

Fig. 1.—The Pit Top Arrangement.

which engages with a cleat on the bottom hoop of the
cage. The sliding bar C on the top platform assumes
its original position by reason of a balance weight
attached to the end of the roller-lever B, before the
main cage drops- back on the keps. As soon as the
main cage comes to rest on the keps, the tub-stops (or
axle-catches) are released automatically, the stops on
all three decks being connected by means of a system
of levers to a vertical bar placed on the outside of the
main cage. This bar has an outward projection near
the upper end. which engages with the sliding bar C
on the top platform just at the moment when the cage
is. settling on the keps, resulting in the axle-catches
being dropped clear of the axles. The action of the
cage settling on the keps also brings a cleat, fixed to
the side of the cage, into contact with the hinged
sliding bar S under the lower platform, and depresses
the lever N which carries the hinged end, which lifts
the notched locking-lever M2, thus releasing the
final lock of the main locking-bar V.

The locking devices all being released, the banksman
pushes down the foot-lever M, which serves to unlock
the push-out valve-lever G, and which can then be
operated. On the bar which locks the push-out valve
is a wedge-shaped block L, which is adjustable, and
is arranged to give a small adjustment in relation to
the lever G2, with which it engages.

When the main cage and the two secondary cages on
one side of the pit are in their correct position, and the
push-out valve P is unlocked, pressure is admitted
to the push-out ram, so that the tubs in the main cage
are pushed out, their place being taken by those which
filled the secondary cage.

The releasing of the tubs in the secondary cage is
effected by an automatic gear, actuated by the pushing-
out carriages (see fig. 1), and which comes into operation
the moment that the push-out rams are put in motion,
but this cannot take place until all the cages are in their
correct positions, and have withdrawn their respective
locking-levers from the main locking-bar. The vertical
rod at the side of the cages, to which the axle-catches
are connected, is raised by a curved lever working
through a cast iron bracket on the structure. On the
spindle which carries the above lever is keyed another
lever, which in turn is connected through a rod and
shaft to a roller lever. This roller lever travels on
a channel path provided for it over one of the pushing-
out rods. As soon as the pushing-out carriage is put
in motion, the above channel path comes in contact with
the roller lever, which in turn actuates the gear Operating
the axle-catches, lowering the latter and thus releasing
the tubs. The whole is so arranged however, that the
axle-catches are entirely clear of the tub axles before the
push-out rods engage the tubs.

On the shaft which carries the roller lever there is

a valve and admitting pressure to the elevating ram on
the side being operated. This holds the secondary cage
up against the stops fitted to the structure, and ensures
the decks being maintained at the correct level during
the pushing - out stroke. The valve operating the
elevating ram is also effectively locked by the latch
until the return of the pushing-out ram to rest. By
this device it is impossible for the secondary cage to
drop back below its proper level, should there be a
slight leakage in the stuffing box of the elevating ram,
or from any other cause.

To the rail girder carrying the pushing-out carriage
is fixed a vertical lever, which is connected by means
of chains and levers to the sliding-bar C on the top
platform (see fig. 3).

When the pushing-out carriage is on its forward
stroke, it trips this vertical lever, causing the sliding-
bar C to be withdrawn from under the projection on
the axle-catch connecting rod of the main cage, and
permitting these catches to resume their normal position,
and so stop the incoming empty tubs just at the moment
when the out-going full tubs have run clear of the axle-
catches. By this means the empty tubs cannot follow
the full tubs off the main cage.

As soon as the catches on the main cage have dropped,
the sliding-bar C is pushed forward again by the
balance-weight F placed on the top platform. The
banksman can now release the push-out valve lever, and
the valve immediately opens to exhaust, by reason of
the balance-weight on the end of the lever G2. The
foot-lever M is also released, and the push-out valve
locked by means of the wedge-block L.

The push-out ram and carriage are drawn back to
rest by means of chains and balance weights, and
during this return stroke the valve of the elevating ram
is unlocked, and finally the catches on the secondary
cage resume their normal position, ready for the next
lot of tubs.

On the signal being given for the main cage to
descend, the banksman pulls the kep hand-lever over to
open position, and holds it there until the cage has
gone past, in the same manner as he would operate an
ordinary kep-lever. By this same operation the sliding
bar S on the lower platform is withdrawn clear of
the cage, so as to allow the latter to pass, and at the
same time the main locking bar is finally locked by the
notched lever M2 dropping on the pin. The kep
hand-lever on being released returns automatically to
the shut position, ready for the next unloading operation.

The movements described above complete a full cycle
of operations at the pit top.

A drawing of the plant at the pit bottom is shown in
fig. 2, and the working of the latter plant is practically
similar to that on top.

Two men are sufficient to handle each terminal of

-Elevation

Fig. 3.—Locking Gear for Pit Top.

•Empty side







IE'

-Eno Elevation -

taining pressure in Hie opposite rams. The main
cage is fitted with a projection, which lifts and trips
the roller-lever B, which in turn actuates the vertical
shaft A of the locking gear. This action takes
place when the main cage reaches the level of the keps,
and results in the withdraw al of the sliding bar C on
the top platform, so as to clear the projection on the
axle-catch connecting-rod, and at the same time pushes
forward the sliding bar S on the lower platform,

another lever fixed, which is connected by means of rods
and links to the latches which lock the raising valve
operating the ram of the secondary cage on the push-out
or full side of the plant.

When the roller lever engages with the path on the
pushing-out rod, the locking latches on that side of the
plant which is being operated, are raised, the wedge
portion causing a sliding bar through which it works to
be drawn over, the movement of this sliding bar opening

the pit top or bottom, whereas before the installation of
this plant, about three men were required at each
terminal, or a saving of one-third of the labour. It also
took 50 to 55 seconds for each wind, and 45 to 50 seconds
to change the six tubs by hand, three men being
engaged at each terminal “ onsetting ” and “ taking-off,”
under normal continuous working conditions.

With this new plant, however, the number of winds
per hour will be increased from 36 to about 55 when