Improvements in Apparatus for Conveying Electric Current from Overhead Conductors to Motors on Tramcars or like Vehicles.
Year: 1896

page_text: Date of Application, 30th Jar., 1896
Complete Specification Left, 24th Oct., 1896-Accepted, 28th Nov., 189€
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Conveying Electric Current from
Overhead Conductors to Motors on Tramcars or like Vehicles.
I PHILIP DAWSON of 39 Victoria Street in the City of Westminster Civil and
Electrical Engineer do hereby declare the nature of this invention to be as
follows:-
6
This invention relates more particularly to the appliances, generally termed
trolleys" for conveying electric current from overhead conductors to motors on
tramcars, or like vehicles, and has for its object to obtain an efficient contact between
the trolley and the overhead conductors with which it works, whilst the parts are
better insulated, and also better protected from injury and rain, or dirt, than is the
case with such appliances as have hitherto been made, and generally to simplify and
improve the apparatus.
This invention has special interest as applied to tramcars having roof seats, where
it is essential that passengers on the upper deck shall be protected from possible
contact with the electric current. It also presents great advantages where local
requirements render it necessary or advisable that the conducting wires be
supported at points not coincident with the line of the rails along which the car
or vehicle runs.
To any suitable part of the roof of the tramcar is bolted, or otherwise secured, a
post, or hollow column, through which passes the electric conductor in connection with
the motor. To the upper end of the said post, or column, is secured a box, or
receptacle, containing a device for maintaining electric contact at the joint which has
to be provided to enable the trolley to move round to follow the line of the overhead
conductor during the travel of the vehicle and to properly convey the current to the
motor. The said receptacle consists of a lower part which is rigidly fixed to the post,
or column, (or in the case of tramcars or other vehicles which do not employ roof seats,
to the roof itself) and a part which is capable of rotating in the said lower part, ball
bearings heing preferably divided between the fixed part and the rotatable part to
reduce friction. In the rotatable part is a recess, or chamber, in which is placed a
metal cylinder enclosed in an outer casing of india-rubber, or other suitable insulating
material. To the upper end of this metal cylinder is connected one end of the
conductor leading to the roller or piece, which makes contact with the overhead
conductor. Inside this cylinder is a metal disc, or piston, provided with a rod which
extends through the lower end of the cylinder and through an opening in the
surrounding casing of insulating material and also through a central opening in a
plate secured to the rotatable part to retain in position the cylinder and its
enclosing insulating casing. The piston rod is connected by screw coupling, or
otherwise, to the portion of the conductor which leads to the motor. Between the
piston and the upper end of the cylinder, or a piece in contact therewith, is placed a
helical spring which forces the contact pieces together to ensure good electrical
contact and to compensate for wear. The rotatable portion of this receptacle, and
also the part which is secured to the column, or post, may be made of cast iron and
may be provided with steel, or other hard metal bearing surfaces, to work in contact
with the antifriction balls. The rotating part is provided with a depending rim, or lip,
which surrounds the upper portion of the stationary part so as to prevent the entrance
of rain and dirt. It is also provided with lugs to which a spring box is pivotted, to

page_text: which spring box is connected the hollow arm of the trolley through which passes the
portion of the conductor carried thereby. The said hollow arm may be made of steel
covered with india-rubber or other suitable insulating material, and the end thereof,
which is connected to the spring box, is made of a square form, or other than
circular form, to enter a socket of corresponding form on the said spring box whereby
the said arm can, with ease and certainty, be placed in proper position and it cannot
inadvertently be placed in a wrong position. To facilitate the insertion of the arm in
the socket one side of the said socket may be made removeable and be secured to the
other part by screws, or bolts, or other suitable fastenings. The spring box contains
a volute, or spiral spring, or volute, or spiral springs, one end of which (or of each
of which) is secured to a spindle mounted in bearings in the sides of the box, the
opposite end of the spring or ends of the springs, bearing against, or being secured to
the interior of the box. One end of the spindle which projects outside the box is
squared to receive a key by which the spring, or springs, can be wound on the spindle,
to regulate the power of the spring, or springs, as required, a ratchet wheel and
detent being provided to retain the position of the parts. This arrangement presents
the additional advantage of allowing the tension of the springs to be readily relaxed
whenever the trolley is not in actual service, thus relieving the parts from unnecessary
strain. The spring box may be made of cast iron, and may be in parts which are
separable, or one side only may be made removeable for the insertion of the spring, or
springs, or for other purpose. To ensure the roller, or pulley, which bears against
the overhead conductor being placed on the hollow arin in the correct position for
bearing against the said overhead conductor the upper end of the said arm is made
square, or of other non-circular form, to receive a correspondingly shaped socket of
insulating material contained in a metal cap to which the upper end of the
conductor of the trolley is connected by a nut screwed onto the end of the said
conductor, or in other convenient way; a square, or equivalently shaped,
washer on the end of the conductor entering a correspondingly shaped recess in
the end of the socket to prevent the conductor being twisted when the nut is
screwed thereon to fix the said socket. Projecting from the upper side of the
socket, is a stud, or projection, on which is fitted, so as to be capable of swivelling
thereon, the socket of a fork carrying the grooved wheel, or pulley, to bear against
the overhead conductor, and, to prevent the socketted fork-piece carrying the said
wheel, or pulley, from becoming detached from the stud, an annular groove can be
made in the stud to receive the end of a screw-pin passed through the side of the
socket.
To facilitate the fixing of the cap onto the end of the hollow arm the said cap
may be made in parts connected together by screws, or bolts, or other fastenings.
Dated this 30th day of January 1896.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.
Improvements in Apparatus for Conveying Electric Current from
Overhead Conductors to Motors on Tramcars or like Vehicles.
I, PHILIP DAWSON, of 39 Victoria Street, in the City of Westminster, Civil and
Electrical Engineer, do hereby declare the nature of this invention and in what
manner the same is to be performed to be particularly and ascertained in and by
the following statement:-
This invention relates more particularly to the appliances, generally termed "trolleys"
for conveying electric current from overhead conductors to motors on tramcars, or
like vehicles, and has for its object to obtain an efficient contact between the trolley

page_text: and the overhead conductors with which it works, whilst the parts are better insulated,
and also better protected from injury and rain, or dirt, than is the case with such
appliances as have bitherto been made, and generally to simplify and improve the
apparatus.
This invention has special interest as applied to tramcars having roof seats, where
it is essential that passengers on the upper deck shall be protected from possible
contact with the electric current. It also presents great advantages where local
requirements render it necessary or advisable that the conducting wires be supported
at points not coincident with the line of the rails along which the car or vehicle runs.
To any suitable part of the roof of the tramcar is bolted, or otherwise secured, a
hollow post or column, through which passes the electric conductor in connection
with the notor. To the upper end of the said post, or column, is secured a box, or
receptacle, containing a device for maintaining electric contact at the joint which has
to be provided to enable the trolley to move round to follow the line of the overhead
conductor during the travel of the vehicle and to properly convey the current to the
motor. The said receptacle consists of a lower part which is fixed to the post, or
column, (or in the case of tramcars or other vehicles which do not employ roof seats,
to the roof itself) and a part which is capable of rotating in the said lower part, ball
bearings being preferably provided between the fixed part and the rotatable part to
reduce friction. In the rotatable part is a recess, or chamber, in which is placed a
metal cylinder enclosed in an outer casing of india-rubber, or other suitable insulating
material. To the upper end of this metal cylinder is connected one end of the
conductor leading to the roller, or piece, which makes contact with the overhead
conductor.
Inside this cylinder is a metal disc, or piston, provided with a rod which extends
through the lower end of the cylinder and through an opening in the surrounding
casing of insulating material, and also through a central opening in a plate secured
to the rotatable part to retain in position the cylinder and its enclosing
insulating casing.
The piston rod is connected by screw coupling, or otherwise, to the portion of the
conductor which leads to the motor. Between the piston and the upper end of the
cylinder, or a piece in contact therewith, is placed a helical spring which forces
the contact surfaces together to ensure good electrical contact, and to compensate
for wear.
The rotatable portion of this receptacle, and also the part which is secured to the
column, or post, may be made of cast iron and inay be provided with steel, or other
hard metal bearing surfaces, to work in contact with the antifriction balls.
The rotating part is provided with a depending rim, or lip, which surrounds the
upper portion of the stationary part so as to prevent the entrance of rain and dirt.
It is also provided with lugs to which a spring box is pivotted, to which spring box
is connected the hollow arm of the trolley through which passes the portion of the
conductor carried thereby. The said hollow arm may be made of steel covered with
india-rubber, or other suitable insulating material, and the end thereof which is
connected to the spring box, is made of a square form, or other than circular form,
to enter a socket of corresponding form on the said spring box whereby the said arm
can, with ease and certainty, be placed in proper position and it cannot inadvertently
be placed in a wrong position.
To facilitate the insertion of the arm in the socket, one side of the said socket may
be wade removeable and be secured to the other part by screws, or bolts, or other
suitable fastenings.
The spring box contains a volute or spiral spring, or volute or spiral springs, one
end of which (or of each of which), is secured to a spindle which passes through the
sides of the box, and is supported in the beforementioned lugs; the opposite end of
the spring (or of each of the springs), bears against, or is secured to the interior of
the box. One end of the spindle which projects outside the box is squared to receive
a key by which the spring, or springs, can be wound on the spindle, to regulate the
power of the spring, or springs, as required, a ratchet wheel and detent or other

page_text: suitable device being provided to retain the position of the parts. This arrangement
presents the additional advantage of allowing the tension of the springs to be readily
relaxed whenever the trolley is not in actual service, thus relieving the parts from
unnecessary strain.
The spring box may be made of cast iron, and may be in parts which are separable,
or one side only may be made removeable for the insertion of the spring, or
springs, or for other purpose.
To ensure the roller, or pulley, which bears against the overhead conductor, being
placed on the hollow arm in the correct position for bearing against the said over-
head condiretor, the upper end of the said arm is made square, or of other non-
circular form, to receive a correspondingly shaped socket of insulating material
contained in a metal cap to which the upper end of the conductor of the trolley
is connected by a nut screwed onto the end of the said conductor, or in other
convenient way; a square, or equivalently shaped, collar on the end of the
conductor entering a correspondingly shaped recess in the end of the socket to
prevent the conductor being twisted when the nut is screwed thereon. Projecting
from the upper side of the socket, is a stud, or projection, on which is fitted, so
as to be capable of swivelling thereon, the socket of a fork carrying the grooved
wheel, or pulley, to bear against the overhead conductor, and to prevent the socketted
fork-piece carrying the said wheel, or pulley, from becoming detached from the stud,
an annular groove can be made in the stud to receive the end of a screw-pin passed
through the side of the socket.
To facilitate the fixing of the cap onto the end of the hollow arm the said cap may
be made in parts connected together by screws, or bolts, or other fastenings.
I will describe the invention with reference to the accompanying drawings in
which :-
Figure 1 is a side elevation of a tramcar provided with one form of the apparatus
constructed according to this invention.
Figure 2 is a vertical section of portion of the trolley-apparatus shewn in
Figure 1.
Figure 3 is a back elevation of Figure 2, shewing a modification of portion of the
apparatus represented in Figure 1.
Figure 4 is an elevation, partly broken away, of the trolley-head shewn in
Figure 1.
Figure 5 is a view of Figure 4-partly in elevation, and partly in section on the
line 5-5 of that figure.
Figure 6 is a view shewing the means employed for making electrical connection
between the cable passing through the arm and the cap fitted on the end of
said arm.
Figure 7 is an elevation shewing a modification of the trolley-head represented in
Figures 1, 4 and 5.
Figures 2 to 7 inclusive are all drawn to the same scale, and Figure 1 is drawn to
a smaller scale.
Like letters of reference indicate like parts throughout the several figures of the
drawings.
In carrying the invention into practice, I bolt or otherwise secure to the roof o
the tramcar A a hollow post or column B, through which passes the electric
conductor C, Figures 2 and 3, in connection with the motor, which later is not
shewn in the drawings.
On the upper end of the column B is provided a disc or cover D which, with the
annular lip secured thereto, constitutes as it were, a box or receptacle for supporting
a device for maintaining electric contact at the joint which has to be providel
enable the trolley to move round to follow the line of the overhead conductor i
(Figures 1 and 4) during the travel of the vehicle, and to properly convey the curren
to the motor. The lip Di surrounds the upper end of the column and is swivelled o
pivotted thereto by the ball bearing B', so that the disc or cover D and all the part
mounted thereon are free to rotate upon the said column. The above mentione

page_text: contact-mintaining device consists of a casing or chamber F formed in part with, or
secured to, the disc or cover D, and containing a metal cylinder f enclosed in an
outer casing of india rubber, or other insulating material. To the upper or closed
end of the cylinder f, is connected one end of the conductor G leading to the
roller H which makes contact with the overhead conductor E. Inside the cylinder f
is a metal disc f provided with a rod C' which extends through the lower end f of
the cylinder, and through openings in the surrounding casings f' and F. The rod C
is connected to the before mentioned conductor C by a screw coupling or otherwise.
Between the disc f³ and the upper end of the cylinder fa movable contact pieceƒ³
is provided, and a spring f between this contact piece and the disc f³, tends to
maintain the said contact piece always in good electrical contact with the upper
end of the cylinder. The disc f3 and contact piece fare connected together by
means of a stem on the former fitting into a socket on the latter (or vice versa)
a pin and groove 10 serving to prevent these parts rotating independently of each
other. If necessary special means may be provided to secure the rod C and cable C
against being twisted when the upper part of the apparatus is turned round, though
ordinarily this is not found necessary.
The disc D with its annular lip D' and chainber F and the column B may be made
of cast iron and may be provided with steel or other hard metal bearing surfaces db
to work in contact with the anti-friction balls B', suitable rings or collars d¹¹ being
also provided for enabling access to be had to, and for adjusting, the said balls.
The chamber F, when made separate from the disc D, as shewn in the drawings
may be screwed into the said disc, and provided with Ings f" to facilitate such
attachment.
As the lip D completely surrounds the upper portion of the column B and the
part at which the disc D is connected to it, dust and rain are prevented from gaining
access to the interior.
The disc D is provided with lugs D' to which a spring box J is pivotted, to which
spring box is connected the hollow arm K of the trolley and through which arm
passes the conductor G. The said hollow arm K may be made of a steel tube /
covered with india rubber or other suitable insulating material 4', and the end thereof,
which is connected to the spring box is made of a square or approximately square
form, or other than circular form, similar to that represented in cross section in
Figure 5, to enter a socket J', of corresponding form, on the spring box J whereby
the said arm K can, with ease and certainty be placed in proper position, and it
cannot inadvertently be placed in a wrong position. To facilitate the insertion of the
arm K into the socket J the side of the latter may be made removable and be
secured to the other part by bolts and nuts j', screws, or other suitable fastenings.
The spring box contains a volute or spiral spring, or two or more such springs, L
(two are represented in Figure 3), the end 7 of which (or of each of which) is secured
to a spindle L' which passes through the sides of the box J and is pivotally supported
in the before described lugs D2; the opposite end of the spring (or of each of the
springs) L bears against, or is secured to, the interior of the box. One end of the
spindle L' may, as shewn in Figure 1, be squared to receive a key by which
the spring, or springs L, can be wound on the spindle L' to regulate the power
of the spring, or springs, according to the weight, or length, of the arm K, or
height of the overhead conductor E (Figures 1 and 4), a ratchet wheel 12 and spring
or equivalently controlled detent 13 being provided to retain the position of the parts;
or, this regulation may be effected by means of a worm and worm wheel such as
is shewn in Figure 3. The two last described arrangements present the additional
advantage of allowing the tension of the spring or springs L to be readily relaxed
whenever the trolley is not in actual service thus relieving the parts from unnecessary
strain.
The spring box J may be made of cast iron, and may be in parts which are
separable, or one side only, for example, the side in Figure 3, may be made
removable for the insertion of the spring or springs L, or for other purpose.
To prevent the arm K from swinging over too far when the roller H is moved off

page_text: or away from the overhead conductor E, a stop J is provided on the spring box J
which is adapted to bear against a stop D3 when the limit of the upward movement of
the said arm is reached.
To ensure the roller H being placed on the hollow arm K in the correct position
for bearing against the overhead conductor E, the upper end of the said arin (like
the lower end before described) is made square, or approximately square, as shewn
in Figure 5, or of other non-circular form, to receive a correspondingly shaped
socket of insulating material contained in a metal cap or socket M, to which the
upper end of the conductor G is connected.
A convenient way of forming this connection is, as shewn in Figure 6, to solder,
or otherwise suitably secure, a nut on the end of the conductor G, and into the
end of this nut screw a stud or screw g' on which is rigidly fixed a square or other
non-circular collar g adapted to fit the interior of the non-circular socket M. The
screw passes through the upper end of the socket M, and, by means of a nut g,
the collar g is caused to make good electrical contact with the said upper end, while,
at the same time, the collar prevents the cable G from being twisted when the
nut is turned. Projecting from the upper side of the cap or socket M, is a stud or
projection M', on which is fitted, so as to be capable of swivelling thereon, the
socket of a fork A' carrying the grooved roller H, and to prevent the socketted fork
piece from becoming detached from the stud, either the socket & may be formed
with an annular groove h² with which engages a screw m² mounted in a lug m³
projecting from the socket M as shewn in Figure 4, or an annular groove may be
formed in the stud M' to receive the end of a screw-pin passed through the side of
the socket. The arms of the fork are preferably extended beyond the pivot of the
roller H and are suitably curved so as not to present any surfaces or edges to catch
against the overhead conductor E when the roller is being brought into contact
with the said conductor.
To ensure the making of proper electrical contact between the roller H and the
fork in which it is mounted, sheet copper or other strips rivetted, or otherwise
secured, to the inside of the fork are arranged to press against the boss of the
said roller.
To facilitate the fixing of the cap or socket M on to the end of the hollow arm the
said cap (like the socket J¹ previously described) may be made with a removable
part which may be connected to the other or fixed part of the socket by bolts and
nuts or other equivalent fastening devices.
In the trolley head shewn in Figure 7 the fork A is formed in part with the stud /*
instead of a socket as in the preceding example, and the socket MI is provided with a
socket m for receiving the said stud, and at the lower end of the stud is fitted an
arm h to which is connected one end of a spring N the other end of which is
connected to a lug m projecting from the socket M. This spring serves to return
the roller H to its initial position when it arrives at a fixed overhead point or "frog"
so as to cause it to travel along the proper wire; the said spring is not usually
provided where the course of the overhead conductor deviates greatly from the centre
of the trolley standard B as in such a case the wear on the overhead conductor E and
roller H would be excessive.
O, Figure 1, is a cord or equivalent by which the roller H may be drawn out of
contact with the overhead conductor E; B' is a door in the standard B by which
access may be land to the conductor Cor coupling C for repairs or other purposes,
and P are guards or "fenders" secured to the under-frame of the car.
Having now particularly described and a-certained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. In apparatus for conveying electric current from an overhead conductor to a
motor on a tramcar or like vehicle running on rails, the combination with an arm
such as K of a spring-containing box such as J, substantially as hereinbefore
described with reference to the accompanying drawings.

page_text: 2. In apparatus for conveying electric current from an overhead conductor to a
motor on a tramcar or like vehicle running on rails, the combination with an arm
such as K, of a spring-containing box such as J, pivotally mounted in a support such
as D D', movable about a vertical axis, substantially as hereinbefore described with
reference to the accompanying drawings.
3. In apparatus for conveying electric current from an overhead conductor to a
motor on a tram-car or like vehicle running on rails, the combination with a support
such as D D, carrying a shaft such as L', and a box such as J, pivotted on said
shaft, of a spring, or two or more springs, connected to, or bearing on, the shaft
and box, and means for adjusting the effective strength of the said springs, sub-
stantially as and for the purpose herein before described with reference to the
accompanying drawings.
4. In apparatus for conveying electric current from an overhead conductor to a
motor on a tram-car or like vehicle running on rails, the combination with the
conductor leading from the roller or device which makes contact with the overhead
conductor, and the conductor leading to the motor, of a contact maintaining device
which admits of one of said conductors being rotated independently of the other,
substantially as hereinbefore described and illustrated in Figure 2 of the accom-
panying drawings.
5. In apparatus for conveying electric current from an overhead conductor to a
motor on a tramcar or like vehicle running on rails, the combination and arrangement
of parts constituting the complete device substantially as hereinbefore described and
illustrated in Figure 2 of the accompanying drawings.
6. The employment in apparatus for conveying electric current from an overhead
conductor to a motor on a tram-car or like vehicle running on rails, of a roller contact
device substantially as hereinbefore described and illustrated in Figures 4, 5 and 6 or
Figure 7 of the accompanying drawings.
Dated this 23rd day of October 1896.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents..