THE COLLIERY GUARDIAN.

January 8, 1915.

96

to such spindle, and two spring-pressed insulated plungers
carried by the cross head. The switch also consists of two
oil cups suitably insulated and arranged one each below the
plungers, these latter being connected by leads or cables to
an electric generator. To the said spindle is connected a
treadle lever, which extends through a slot in the front side
of the cabinet, and outside the cabinet is provided with a
foot plate. By means of a spring the spindle and treadle
lever are held normally raised, and the plungers out of the
oil cups. The construction of switch thus described is well
suited for withstanding continual use in unlocking large
numbers of lamps. Fig. 1 illustrates a front elevation of
the improved apparatus, the door and a portion of the front
lower part of the cabinet being shown removed; fig. 2 illus-
trates a side elevation of the apparatus with a portion of the
side of the cabinet removed. The improved apparatus may
also be used for re-screwing the bottom caps to the lamps,
the winch handle then being rotated in the reverse direction,
and the magnet not necessarily being used. (Four claims.)

3563 (1914). Improvements in or Relating to Cradles for
Hammer brills or Percussion Drills. H. C. Jenkins, of
Meco Works, Moorfields, Sheffield, Yorkshire.—Relates to
carriages for hammer drills and percussion drills for rock and
the like, of the kind in which the machine proper is inserted
and secured in a carriage working in gibs or guides in a
cradle, in which the carriage can be fed backwards and for-
wards by a screw working in a feed nut. According to the
invention, the drill carriage is provided with a loose feed nut,
that is to say, unattached, but provided with one or more



Fig 4.
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lugs or projections adapted to engage one or more seats or
recesses of the carriage, so that, without being attached
thereto, it is held against rotation, and transmits the neces-
sary thrust to the carriage for effecting the feed. The
renewable nut may with advantage be made of gunmetal,
hardened steel, phosphor bronze, or like metal, but any other
suitable metal may be employed. Fig. 1 is a side elevation
of the carriage, with the cradle removed, and showing a
hammer drill in dash-dotted lines in position in the carriage;
fig. 2 is a rear elevation of the carriage; fig. 3 is a front
elevation thereof; and fig. 4 is a vertical cross section through
the carriage and cradle, taken on the line 4—4, fig. 1; fig. 5
is a separate plan view of the renewable nut. The con-
struction may be varied considerably. For instance, the
nut may extend for any desired portion of the length of the
carriage instead of for the full length thereof, and, as before-
mentioned, a single lug or projection may be employed on
the renewable nut. (Three claims.)

5300	(1914). Improvements in and Relating to Extractors
for Cores Produced During Boring Operations. Neder-
landsche Maatschappij tot het Verrichten van Mijnbouw-
kundige Werken, of Heerlen, Holland. — Relates to an
improved gripper for drilled cores, such as are formed during
boring operations. The improved core gripper is to be used
particularly in connection with core drilling, carried out in
accordance wth the rapidly repeated impact system. One
form of carrying the invention into effect is shown by way
of example in the accompanying drawings which illustrate a
boring apparatus equipped with such a core gripper, and in
which fig. 1 is a longitudinal section through the apparatus;
fig. 2 is a similar section through the same, showing, how-
ever, the core gripper in operation; fig. 3 is a side elevation,
as well as a view, of the core gripper, as seen from below;
and fig. 4 is a view of the drill, which is provided with serra-
tions, as seen from below. The mode of operation of the
apparatus is as follows :—During boring, the core gripper
assumes the position shown in fig. 1, the member 3 being
held in a raised position by the bell crank levers 6 and the
piston 12, with the rod 9, through the action of the spring 10,
whereas the water used for flushing purposes, and entering
through the hollow boring rod, may freely flow through the
piston 12. After the core has been sufficiently drilled, the
ball 11 is allowed to drop into its seat formed by the opening
provided in the piston 12, so that the piston 12, with the
rod 9, will be forced downwards against the action of the
spring 10, by the pressure exerted by the water (fig. 2). The
rod 9 at the same time tilts the small levers 6, and the
gripping member 3 will now be forced downwards by the
action of the spring 5 (fig. 2). As the drill 1 is coned on
the inside, the serrations on the gripping arms 4 are firmly
pressed against and into the core (fig. 2), so that when
pulling up the drill, the core will be broken off and carried
up with the drill. (Two claims.)

5301	(1914). Improvements in and Relating to Apparatus
for Cutting Off the Tubes Used for Lining Boreholes.
Nederlandsche Maatschappij tot het Verrichten van Mijn-
bouwkundige Werken, of Heerlen, Holland.—The object is
to provide an improved apparatus for cutting off the tubes
used for lining boreholes of the type in which the holders
for the knives or cutters are adjusted in position by a
hydraulically-operated piston, so constructed as to ensure a
retraction of the knife or cutter holders after the tube has
been cut off, so that the apparatus may then again be easily
pulled up. Fig. 1 is a longitudinal section through the
improved apparatus; fig. 2 is a section on the line A—B in
fig. 1; and fig. 3 is a view of a detail. The mode of opera-
tion of the improved apparatus is as follows :—After the
sleeve containing the cutting apparatus has been lowered to
the correct depth into the lining tube, water under pressure

is supplied to the space above the piston 1 through the
hollow boring rod by means of a force pump, so that the said
piston will be caused to move in a downward direction
against the action of the spring 13. The plug-shaped
member 4 connected to the rod 3 will thus cause the cutter
holders 6 to be forced outwards, so that the cutters 7 come
into contact with the inside wall of the tube. If now a
rotary movement is imparted at the same time to the
apparatus, then the tube will be cut off. At the moment
when the cutting off process is completed, the nut 8 will
come into contact with the part 12, causing the rings 11 and
14 to move downwards, so that the ports 10 are uncovered.
The water, which is under pressure, can now escape through
these ports, so that the pressure obtaining above the piston
will be decreased, whereas the latter will now be forced
upwards by the spring 13. The piston carries with it the
plug-shaped member 4, so that the cutter holders 6 will be
retracted into the position shown in fig. 1, thus permitting
the whole apparatus to be pulled up and extracted from the
borehole. The ports 10, during the pulling up of the boring
rod, remain uncovered the whole time, so that the water may
escape. The rings 11 and 14 are then moved back into their
initial position by hand. (Three claims.)

5302	(1914). Improvements in and relating to Bits for
Hollow Drills, i.e., Core Drills. Nederlandsche Maat-
schappij tot het Verrichten van Mijnbouwkundige Werken,
Heerlen, Holland.—Relates to an improved bit for drills of
the type which is provided with interchangeable cutters, and
the same is to be used in connection with core drilling opera-
tions. Fig. 1 is a longitudinal section through the improved
bit; fig. 2 is an elevation of the same; and fig. 3 is a view
thereof as seen from below. The drill bit 1, the material of
which is iron or steel, is provided with four or more double
dove-tailed grooves 2, in which pieces 3 may be inserted
that are held in position by a ring 4, which latter is provided
with a conical bore, an'd in conjunction with the core spring
5, also serves as core gripping sleeve. The core spring 5
comprises a split ring, the outer surface of which is conical,
and is adapted to fit the inner surface of the part 4. The

No. 5300.

No. 5301.

B

No. 5302.

inner surface of the ring is suitably roughened, so that when
the boring rod is extracted the split ring will move down-
wardly, and at the same time be pressed around the core.
The interchangeable parts 3 may either take the form of
cutting teeth, in which case the crown is used as a steel
crown, or they may be made from soft iron and studded
with diamonds, in which case the crown is used as a diamond
crown. (Two claims.)

s 10014 (1914). An Improved Riddle to Enable Coal or the
like to be Graded and Discharged into Wagons on one Line
of Rails. J. Donaldson, of 19, Waterloo-street, Glasgow,
N.B.; and the British Riddling Company Limited, of 209,
West George-street, Glasgow.—Relates to riddles of the type
described in the earlier patent specification No. 3480, of 1911,
and has for its object to provide an improved construction
of such riddle to enable coal or the like to be separated into
three different grades, instead of two grades, as in the earlier
specification, and at the same time discharged into wagons
all on one line of rails, the improved riddle being thus of
particular service where there is no room for the usual
arrangement of a number of parallel lines of rails on which
the trucks for the different grades of coal are arranged
beneath a riddle extending transversely to the rails. As
described in the earlier specification, there is provided a
gantry beneath which the wagons can pass, the gantry being
preferably fitted with wheels running on tracks on each side
of the line of rails. Above the gantry a riddle is suspended
by links from the gantry, the riddle being of a length and
breadth such that, whilst it extends over one wagon, its ends
extend more or less over the wagons at each end of the one
covered by the riddle, and means are provided to impart an
oscillating motion to the riddle. To enable the coal to be
separated into three grades instead of only two grades, as
possible with this type of riddle as formerly constructed, the
riddle comprises an upper plate so apertured that all but the
largest grade of coal passes through it. This plate is so
inclined, and of such a length, that whilst it extends over the
central wagon, its lower end projects more or less over one
adjacent wagon, and the largest grade of coal therefore falls
from its lower end into this outer wagon. Beneath the
apertured part of this upper plate there is a shoot similarly
inclined, and all the coal which passes through the upper
plate slides down this shoot, and passes from its lower end on
to a second apertured plate. This second plate is inclined
in the opposite direction, and is also of such a length, that
whilst it extends over the central wagon, its lower end

extends over the other adjacent wagon. The part of this
second plate extending over the central wagon is so aper-
tured that only the finest grade of coal passes through it
into the central wagon, and consequently the second grade of
coal falls from its lower end into the adjacent wagon over
which that end projects. Preferably the screen part of this
plate is composed of tensioned wires, so that clogging is
minimised, and if it takes place, the screen is easily cleared
by striking the wires. A hopper fitted with a door con-
trolling the bottom thereof, and such as is described in the
earlier patent specification No. 4443 of 1913, is arranged on
the gantry beneath the second apertured plate, and above
the central wagon. Thus should the proportion of fine coal
in a load be greater than usual, when the central wagon is
filled, the door at the bottom of the hopper is closed, and
the riddling continued until the two longitudinally adjacent
wagons are filled with coal in larger pieces. Also to facilitate
the use of the improved riddle in the treatment of materials
in which there is more relatively of the first grade or second
grade than of the third grade, so that one or other of the
outer wagons would normally become filled before the centre

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one, there is provided a hopper or hoppers, such as that
described for the fine coal. This hopper may be mounted
upon a framing straddling the wagons, and fitted with
wheels, as is the main riddle gantry. Thus it may be placed
in position to receive either the first or second grade of
material, whichever preponderates. Or two such hoppers
may be provided if both first and second grade preponderate
over third, and the framing carrying these two end hoppers
may be a part of the main riddle gantry, this construction
being of particular advantage where the riddle gantry is to
be a permanent structure, not transportable at a pithead, for
example, and the hoppers of large capacity permitting of the
riddling operation being continued with the hopper doors
closed for some considerable time before discharging the
contents of the hoppers into wagons. The improved riddle
is shown in the accompanying drawings, fig. 1 being a plan
on the line a—a, fig. 2; and the latter figure a longitudinal
elevation. (Four claims.)

12848 (1914). Improvements in or Relating to Rotary
Compressors, Pumps, Motors, and the like. W. G. Abbott,
junr., of Wilton, Hillsborough County, New Hampshire,
U.S.A. — Relates particularly to apparatus in which fluid
compression or suction is maintained by relative movement
between a helical passage, and a body of fluid held in posi-
tion eccentrically to the axis of said helical passage by centri-
fugal force. The invention comprises two rotors, one of
which is hollow and encloses the other. The outer rotor
contains a body of liquid, such, for example, as mercury or
water, which revolves with the outer rotor, and consequently
is under pressure due to the action thereon of centrifugal
force, while the inner rotor is made with a helical or spiral
passage surrounding the axis of said rotor and extending
lengthwise thereof. The inner rotor is eccentrically sup-
ported relatively to the body of fluid within the outer rotor,
so that a portion of each convolution of the helical passage is
submerged in the body of fluid. The invention is shown as
embodied in an air compressor or the like, with both rotors
driven in the same direction, but in such manner that the
partially submerged helical passage of the inner rotor
revolves relatively to the body of fluid that is under pressure
from centrifugal force. As a result, each convolution of the

helical passage is occupied and closed in part by a body
of the fluid, which occupies the submerged portion of the
convolution, while the remaining portion of each convolution
is occupied by air or other fluid that is being compressed. As
the helical passage rotates relatively to the fluid, the portions
of the fluid occupying the submerged parts of the convolu-
tions do not rotate with the helical passage, but traverse the
latter, so that these bodies of fluid, which are segmental in
form, act as pistons to propel the air, or other matter being
compressed, along the helical passage from the inlet end to
the discharge end thereof. (Five claims.)

Messrs, the Cremer Lamp and Engineering Company
Limited (Moorfield Works, Whingate, Wortley, Leeds)
inform us that the connection between the firm and Mr.
Chas. Willan has been severed, and that the latter no
longer represents them in London or elsewliere. Very
shortly another gentleman is to be appointed to this
position. •