Improvements in Apparatus connected with Flexible Electrical Conductors, and in Electrical Connections therefor, applicable for use in Mines,
Year: 1892

page_text: Date of Application, 29th Nov., 1892-Accepted, 21st Jan., 1893
COMPLETE SPECIFICATION.
Improvements in Apparatus connected with Flexible Electrical
Conductors, and in Electrical Connections therefor, applicable for
use in Mines,
We, CLAUDE WILLIAM ATKINSON, of 17 Victoria Street, Westminster, in the
County of Middlesex, Civil Engineer and THE ELECTRICAL COAL CUTTING
CONTRACT CORPORATION LIMITED, of the same address, do hereby declare the
nature of our invention, and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement :-
Our invention relates to apparatus for use with flexible electrical conductors,
and in electrical connections applicable for use in mines; and has for its object,
firstly, the picking up or paying out of the flexible electric cable, which is con-
nected to a moving machine for the transmission of electric energy thereto, thus
saving time in arranging the cable by hand, and also maintaining all the slack
cable in a safe position on a support out of the way of destructive influences; and
secondly, to arrange a connecting device, which shall be locked in position, and be
so constructed as to make and break the circuit, without the sparking consequent
thereon doing any damage.
i .
It is found in the use of electrical machinery, where the machine and motor are
moveable, and have to be connected to the main electric cable at certain intervals
of distance by a flexible cable as the work progresses, that considerable time is
lost in laying out, and taking in, this flexible lead, and also the flexible cable runs
very considerable risk of being damaged, especially in mining operations; also
that where connection of the flexible cable has to be made in an explosive atmo-
sphere, great care must be taken, so that the violent sparking that takes place
when the contact is broken is confined within a space not communicating with the
explosive atmosphere, and that it is necessary to arrange the connecting device, so
that sparking in the inflammable atmosphere cannot take place however carelessly
the connection is made. These couditions and advantages are effected by our
invention.
Our invention consists, firstly, in a winding drum carried on carrying wheels, the
said drum being adapted to wind the electric cable upon itself, and driven by the
carrying wheels through friction gearing, a collecting device being provided to
complete the electrical continuity of circuit from the cable on the rotating drum,
to the fixed length of cable attached to the motor of the machine to be driven;
and secondly in an improved and special construction of junction box and contact
breaker, with a lock up fastening, so arranged that the breaking or making of the
contact can be effected in such a way that the production of violent sparking
during the operation is not dangerous or does no damage.
In order that our invention may be the better understood we will now proceed
to describe it in relation to the drawings hereunto annexed, reference being had
to the letters and figures marked thereon. Like letters refer to like parts in the:
various figures.
Figure 1 is a sectional plan of our cable drum device.
Figure 2 is a side elevation of the same.
Figure 3 is a detail of the collecting rings, showing the electrical connections.
Figure 4 is a detail view of the contact pieces.
Figure 5 is a side elevation of our improved junction box and contact breaker.
Figure 6 is a plan of the same.
Figure 7 is an end view of the movable part of the junction box attached to the
contact breaker.

page_text: Figure 8 is a detail view of one of the spring contact devices of one
breaker.
Conta
Figure 9 is an end view of the connecting piece attached to the flexible cable.
Figure 10 is a view of the locking key detached.
To carry out our invention, we arrange a winding drum A, so as to be pivot-
ably mounted on carrying wheels B B. In Figure 1 it will be seen that the
drum A, carries a trunnion C on its right hand side, which forms the axle for the
right hand wheel B, while on the left hand side, the trunnion C of the wheel B is
carried by a box D, and the drum A. is journalled at this end upon the said box D,
by means of the ring or clips E, secured to the drum A, and engaging over the
flange of the box D.
The box D is fixedly attached to a light frame F, which is journalled about the
trunnion C at the other side.
This frame F has an arm G or other attachment for manipulating and propelling
the device, which may conveniently be attached to the moving machine and move
along with it, the means for attachment shown is an eye H.
The right hand wheel B we provide with an internally toothed ring J, and into
this gears a cog wheel K pivotted on a pin L mounted on the frame F; on this
said spindle L another cog wheel M is loosely mounted, and arranged to be driven
by frictional contact by the cog wheel K, the pressure being produced between
the frictional driving surfaces by the spiral spring N. The wheel M in turn
gears with the toothed wheel O, situated on, or forming part of, the drum A.
Within the box D we place a collecting device, which consists of two collecting
rings PP, which are in contact with, and journalled by, three or more contact
pieces Q. These contact pieces Q we make of a series of flexible metal strips R,
which are bent so as to make contact by elastic pressure against the inner faces of
the flanges of the rings PP. These pieces Q are supported by fibre insulating
pins Q, supported in the box D, and kept in place by bolts R screwed into the
box. The cage T into which the fibre pin Q' engages, is made hollow, and contains
a spiral spring R², to keep the strips R out against the flanges of the ring P, as
shown in Figure 4. This arrangement forms a floating contact as described and
claimed in Letters Patent No. 15864 and dated the 3rd day of September 1892.
The rings P P have each a driving pin U, which is arranged excentrically so
that by engagement of the said pins in respective holes in the fibre block V,
attached to the end of the drum A; the rings P P are driven crank fashion by the
barrel A.
The two leads of the flexible cable are lead down through a hole in the drum A,
and are connected to their respective pins U U.
It will thus be seen that the rings and their contacts are insulated from one
another, and from the drum, but revolve with it.
The contact pieces Q are connected together by conductors, as shown in Figure 3,
and a cable is lead therefrom to the outside of the box for attachment to the main
circuit.
The provision of three contact pieces ensures a considerable area of contact
surface between the fixed contact pieces and the moving ring.
The working of the device is as follows:-The flexible cable is connected to the
main at one end, and is wound round the drum at the other, and the leads from
the contact pieces Q are connected to the motor to be driven; as now the motor
and machine travel along in the execution of its work, the drum device is moved
with it, and the carrying wheels operate the drum and wind up the cable upon it.
Should the diameter of the drum, upon which the cable is being wound, be such as
to have too great a peripheral velocity, in comparison with the rate of movement of
the machine forward, this difference is dealt with by the frictional driving gear,
and so soon as a given tension is exerted on the cable, the friction wheels slip one
on another, and the drum loses a certain amount of the motion of the carrying
wheels.
This tension on the cable has also the advantage of keeping it off the ground.

page_text: We will now describe the device situated at the fixed end of the flexible cable,.
which connects it to the main cable, and the contact breaker attached thereto
within a closed junction box.
The ends of the flexible cable a are connected to a connector b, having two
connecting pieces c, with spring tongues c'. These connecting pieces c are contained
within a casting d, and supported therein by bitumen or other insulating compound e,.
which can be poured into the casting d in a molten state, the pieces c being held in
position during the pouring in of the insulating material. On the underside of this
casting d, two lugs fare arranged, having a hole g through them, of such a size, as
to permit the round key to be passed through them to lock this connector b to its
counterpart j. This part j carries the female portion of the connecting pieces,
which are partially contained in a cast casing, and insulated and supported_by
bitumen or other insulating compound, as in the other part of the connector. The
piece has an extension m, which has an insulating sleeve n, and is adapted to slide
in and out of the contact box o, which is closed in to prevent access of any flame or
spark, created inside, to the surrounding atmosphere. The casting has a lug p
arranged on its lower part, adapted to slide upon a rod g supported in the box o;
it also has another lug r, so arranged that when the parts j and b are electrically
connected together, the key h will pass through the lugs ff on the part and the-
lug r on the part j, and thus lock them together. In the upper portion of the lug
a spring pressed bolts is arranged to slide, which when the key his withdrawn, is
forced out of its recess by its spring, and can engage in a recess t on the rod 9. A
pinu is fixed on this rod 9, to prevent the part from being pulled right off the
rod The key is provided with a chisel edge at one end, and has a small
curved-shape recess w in its centre portion. The inner end m¹ of the piece m is
made taper, so as to engage with a spring contact piece .. This spring contact
piece is mounted upon an insulating base y of slate or other equivalent material,
supported in the box o; and consists of two arms a¹¹, mounted pivotably about.
a bolt 2, and pressed together by springs a³ ³.
A binding screw is provided on one of the arms, to make the connection to
the main conductor a', and a pin ¹ is mounted on the insulating base y to act as a
stop to resist the rotation of the arms around their supporting bolt .².
In each of the arms a¹ a semicircular conical recess is formed, so that the two
recesses, abutting against one another, form a conical hole, into which the end m¹
of the male contact piece m can engage, to complete the circuit.
The main object in view in the design of this device, from a manufacturer's
standpoint, is that good electrical contact can be effected without the necessity of
accurate, expensive and careful placing, adjustment, and fitting of various parts,.
that have to co-act one with another, and thus cheapen the cost of construction.
We will now describe the method of using this part of our invention, and will
repeat that the purpose of the device is to prevent connection being broken or
made with the main circuit, except when the contact-breaker is in its opened, or
circuit-broken position, so that no sparking can take place in the surrounding
atmosphere.
The device, as shown in the drawings, is in the position in which the circuit is
closed with the main circuit, to allow the current to pass for working the machine;
to disconnect the connector 6 from the stationary junction box o, the whole
connection and j is slid from left to right along the rod 7, until it is stopped by
the pin u; this breaks the connection at a, between the main circuit and the
flexible lead, by the connector m² becoming disengaged from the spring
contacts. The key h could not be removed from the lugs ff and, in the
closed-circuit position, because the recess W, in its side, engages over the pin q;.
however in the left hand end position of the connectors the key his situated over
the recess t, and can thus be withdrawn from the lugs ff and r, as the recess t is
deep enough to allow the key to move longitudinally, without the sides of the
recess W in the key h fouling the pin q. The key h having thus been withdrawn,.
the spring pressed bolt s is pushed by its spring into the recess t, and the

page_text: connector is locked in its left hand endmost position. The connector & can now
be disengaged from the connector j.
The key is chained to the connector b, so that it is always handy to enable
the connection to be made, as it cannot be made without it. When the connection
is to be made, the connectors b and j are engaged together, the key is passed
through the lugs ff and r. and in its passage the chisel edge passes under the
spring-pressed bolts, and pushes it up out of engagement from the recess of the
rod; the key is pushed along until its recess W is opposite the rod 4, and
allows the whole arrangement to be pushed along into the closed-circuit position,
as shown in Figures 5 and 6.
This particular sequence of operations must be gone through to connect or
disconnect the flexible cable from the junction box, as it is obvious that the key h
cannot be removed to unlock the connectors from one another, to disconnect,
except in the left hand endmost or broken circuit position, and in connecting up
should the key h be inserted into the lug only, the bolts lifted, and the
connector slid along, so that the contact-breaker has its contact made, the
connector could not be engaged on to the connector j, on account of
the projections f¹ on the lugs f, coming in contact with the key h, and thus the
contact pieces c could not touch or make contact with the pieces 1.
C
The junction boxes o are situated at various distances along the road or
heading of the mine, and as the machine with the cable drum comes up to a
junction box, the connector is disconnected, carried along, and connected to the
next junction box further ahead.
It will be noticed that should any considerable tensional strain be exerted on
the flexible cable, the contact-breaker will be operated before the cable is
fractured, and thus the sparking that would result from such fracture is avoided.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1st. A movable cable supporting device consisting of a drum mounted on
carrying wheels, and adapted to be driven by frictional gearing from the said
carrying wheels, and a collecting device, consisting of contacts rubbing on rings,
to maintain the continuity of the electrical circuit between the cable wound upon
the drum, and the other fixed portion of the circuit, substantially as described.
2nd. The arrangement and construction of a movable cable supporting device,
substantially as described and shewn in Figures 1, 2, 3, and 4 of the accompanying
drawings.
3rd. A junction box, consisting of a connecting piece or pieces, attached to a
flexible or branch cable, and adapted to make electrical connection with, and be
locked to, one part of a make and break device, enclosed in a box, and connected
to the main circuit,' so that the connection of the flexible cable can only be:
connected to the junction box, when the make and break device is in the circuit-
broken position, substantially as and for the purposes described.
4th. The arrangement and construction of a junction box and connections,
substantially as described and shewn in Figures 5, 6, 7, 8, 9, and 10 of the accom-,
panying drawings.
Dated this 29th day of November 1892.
• FELL & WILDING,
1, Queen Victoria Street, London, E.C., Agents for the Applicants.