Improvements in the Collectors and Conductors of Electric Railways.
Year: 1896

page_text: Date of Application, 16th Apr., 1896
Complete Specification Left, 18th Jan., 1897-Accepted, 20th Feb., 1897
PROVISIONAL SPECIFICATION.
Improvements in the Collectors and Conductors of Electric
Railways.
I, PERCY WILLIAM THOMAS DAVIES, of 32, Victoria Street, in the City of
Westminster, Electrical Engineer, do hereby declare the nature of this invention
to be as follows:-
My invention relates to electric railways of the kind or class in which energy is
supplied to the car through contact bars or shoes carried upon the car which make
connection with fixed contact-pieces or bars laid in the track. My improvements
have especial reference to those railways wherein the fixed contact pieces or bars
are divided into sections each of which is insulated from the main leads except when
the contact bar or shoe of a car is touching said section whereupon an electro-
magnetic switch operates to put the section into connection with the mains.
According to my invention I provide improved contact bars to be carried by the
car and also improved arrangements of the contact pieces fixed in the track. In
one well known method of operating these railways the contact pieces in the track
take the form of studs secured at proper intervals along said track and the bars
carried by the car are of the same width throughout their length. It is found
necessary in these cases to make the studs either of an elliptical shape or larger
when the line is curved as otherwise the moving contact bars will not touch the
studs at all positions of the car. To avoid the use of wide or larger studs I
construct the moving contact bars with a broadened face for some distance each
side of the centre of their length so as to ensure with round studs of the normal
size that some part of the bar shall always touch the studs.
The
My improved arrangements of the fixed contact pieces refer to the cases wherein
said contact pieces take the form of continuous long bars divided into sections
insulated from each other, each section being energized only when in contact with
the contact shoes carried by a car standing or running on the section.
moving contacts carried by the car preferably have the form of two or more
sets of short shoes, or in some cases wheels, connected to a common terminal in
the car.
When the car leaves one insulated section from which it has been receiving
current some time elapses before the next section is connected-with the main owing
to the fact that the electromagnetic switch requires time to operate and even
though the time is small yet when the speed of the car is high, fifty or sixty miles
per hour for example, a considerable distance will have been passed over before
the car receives current from the new section. To avoid this discontinuity in the
supply of current I arrange that the fixed contact bars of one section shall overlap
the contact bars of the next section extending side by side for some distance and
that the moving contacts shall be wide enough to connect with both bars. By this
arrangement before the car leaves one section the next section is being connected
to the main and by the time the cars enters the next section the connection of said
section will be completed and current will be supplied to the car without any
break. Instead of this arrangement of overlapping fixed contact bars I sometimes
use in place thereof the arrangement which I will now describe. The car is
provided with at least two sets of contacts one set at each end thereof, each track
ection is divided into three parts consisting of a short length at each end separated
rom the middle portion by the short lengths at each end of the two adjacent

page_text: track sections. The order of sections will then be as follows, first the middle and
principal portion of section A, next a short length of the next section B, then a
short length of section A, then the middle part of section B, a short length of
section C, and so on. The short lengths are made of such dimensions that when
one of the car contacts is touching such short length some other of the car
contacts must be touching one of the adjacent lengths. Under these circumstances
as the car is approaching the end of section A it connects with the end lengths of
section B and maintains such connection for some distance by one or other of its
contacts, until it connects with the middle portion of section B. At the same
time however its connection with section A is not broken until it finally leaves the
short end length of said section. The car will therefore always be receiving
current from one or other of the sections since the dimensions of the car and short
lengths of the sections are such that at the maximum speed of the car the electro-
magnetic switch shall have time to operate while the car is moving over the two
short lengths of two adjacent sections. This arrangement of sections is especially
useful at junctions and crossings and I prefer to arrange that the actual crossing
of the rails shall occur at or near the end of the middle portion of a section. For
a short distance, less however than the distance between the first and last sets of
contacts on a car or train, the fixed track contact bar is omitted, its place being
taken by a dummy contact bar which is always insulated, as soon as the junction is
past I place the two adjacent short end lengths so that the two lines of rails can
have their fixed contacts insulated from each other. It is obvious that the greater
the distance between the foremost set of contact shoes on a car and the last set of
such contacts the longer may be the short lengths of the fixed track sections and
the longer may be the dummy bars at a crossing. I sometimes therefore in the
case of trains of cars furnish a contact bar or shoe at each end of the train and
connected to a common terminal on the locomotive and in these cases I find it
possible to dispense with the special arrangements of fixed contact bars at the ends
of the sections herein before described.
When it is only necessary for one of the fixed track sections (of which there are
usually two) to be connected to the car for the purpose of working the electro-
magnetic switch, this section may overlap the end of the preceding section or be
divided into three lengths the other track sections having a middle portion and one
short end length.
My invention may be considerably varied in detail and I especially reserve the
right to make alterations that may be desirable in the relative lengths of the fixed
and moving contact bars.
My invention is applicable to systems wherein trains of cars are used propelled
by electric locomotives at either or both ends as well as to those systems wherein
single cars only are used.
Dated shi
1
W. P. THOMPSON & Co.,
322, High Holborn, London, W.C., Patent Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Collectors and Conductors of Electric
Railways.
1, PERCY WILLIAM THOMAS DAVIES, of 32 Victoria Street, in the City of
Westminster, Electrical Engineer, 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 :-
My invention relates to electric railways of the kind or class in which energy is

page_text: supplied to the car through collecting bars or shoes carried upon the car which
make connection with fixed contact pieces or bars laid in the track. My improve-
ments have especial reference to those railways wherein the fixed contact pieces
or bars are divided into sections each of which is insulated from the main leads
except when the contact bar or shoe of a car is touching said section whereupon
an electromagnetic switch operates to put the section into connection with the
mains.
According to my invention I provide an improved form of collecting bar which
obviates the inconvenience arising froin the alteration of the shape of the fixed
track contacts which has hitherto been required at curved parts of the line.
I further improve the construction of the fixed track contacts in order to ensure
that before the car leaves one section of the line the next section shall be connected
with the 'main.
In order that my invention may be clearly understood I will now proceed to
describe the same by the aid of the accompanying drawings, in which :-
Figure 1 is a plan of an improved form of contact bar.
Figure 2 is a diagram illustrating a portion of a track provided with improved
fixed contacts constructed according to my invention.
Figures 3 to 6 are similar diagrams illustrating a modified construction of fixed
track contacts and shewing a car at different parts of the track.
Like letters of reference denote'similar parts in all the drawings."
Referring now to Figure 1, in one well known method of operating, the fixed
contact pieces in the track take the form of studs secured at proper intervals along
said track, and the current collecting bars or shoes carried by the car are the same
width throughout their length: When the line is curved the contact studs which
are arranged at the same distance from the inner or outer rail as they are upon
straight portions of the line necessarily lie upon the curve and consequently at
some points the collecting bar'carried by the 'ear will miss the studs and the supply
of current be thus cut off: In order to obviate this it has heretofore been the
custom to make the studs larger and wider than those in the straight portions of
the track or of an elliptical shape. It has sometimes happened with these
enlarged studs that when two collecting bars are carried by the car to make contact
with two separate series of fixed 'track contacts, that one of the bars touches one' of
the contacts of each series at the same time thereby shortcircuiting 'the ear
battery. To prevent the possibility of this happening I provide a collecting bar
which is wider at the middle part of its 'length' as shewn at A the normal 'width' of
the bar being that shewn at B and by this means I ensure that with track contact
studs of the ordinary size some part of the bar will always be in contact with the
studs even when the car is rounding a curve.***
My improved fixed track contacts are intended for employment in the cases
where said contacts take the form of long bars divided into sections insulated from
each other. Each section is energized only when a car is standing or running on
the section, the moving contacts carried by the car preferably having the form of
short shoes or in some cases 'wheels adapted to connect with the fixed contact bar
in the track. If we assume that the car carries two sets of such contact 'shoes one
in front and the other in the rear when the front contact shoes leave the one track
section and enter another track section the car will be still receiving current from
the section it is leaving, while the section which it is entering will be connected
with the main through the automatic switch which is energized by current from
the battery carried on the car supplied hy the forward 'contact shoes. Further,
when the rearmost set of contact shoes have left a section 'the car will only be able
to receive current from the section which it has just entered, consequently 'the time
allowed for the working of the electromagnetic switch by the battery current in
order to connect a section is equal to the time taken by the car to travel' the
distance between its foremost and rearmost contacts which is approximately equal
to the length of the car. In the case of cars running at a speed of say sixty miles
an hour or eighty-eight feet per second in which the distance between the forward

page_text: and rearward contacts is thirty feet the time allowed for the electromagnetic switch
to work will be very little longer than one-third of a second which in many
instances is too short, consequently the car will experience a check owing to the
fact that every time it enters a section current is cut off from it for a short time.
To avoid this discontinuity in the supply of current 1 arrange that the fixed
contact bais of one section shall overlap the contact bars of the next section
extending side by side for sume distance as shewn at C D Figure 2 in which
figure E E are the rails and C D the fixed contact bars. The moving collecting
bars carried by the car are made wide enough to connect with both fixed bars at
the places where they overlap. By this arrangement before the foremost contact
carried by the car leaves one section it touches the next section and the current at
once begins to operate the electromagnetic switch so as to connect the next section
to the main. By lengthening the distance through which the sections overlap the
time allowed for the magnetic switch to work can be extended as much as
desired.
Another arrangement for effecting a similar purpose is illustrated in Figures 3
to 6. The car is provided with at least three sets of contacts and the track
sections are made in three parts having a short length at each end separated from
the middle portion by the short lengths at each end of the two adjacent track
sections. This will be readily seen from Figure 3 in which E E are the rails
CD the fixed contacts of one section and. F G the fixed contacts of the next
section in front, H the car running on wheels H. The car as shewn is provided.
with four sets of contacts each set consisting of two contacts adapted to connect
with the fixed track sections. The foremost pair of contacts is marked I I¹, the
second JJ, the third K K and the fourth L L'. H2 is the car battery
one pole of which is connected. to the shoes. I J K L the other pole being
connected. to the contacts. I J K L H³ is the car motor one terminal of
which is connected to the contacts I J K L the other terminal being connected
to a brush H carried by the car and adapted to make contact with with
the rail E which is connected to or may be the return main. Said rail E' is
sometimes one of the rails on which the car runs. The outgoing main is shewn
at M which is connected through an electromagnetic switch of a well known type
as shewn at C to the track section the other said rail C being connected through
a coil C³ to the track section D. The electromagnetic switch. F is connected in a
similar fashion between the track section F and the main M the coil F being
connected between the track sections F and G. The detached portion of the track
section C is shewn at.C and is connected to the middle, or main portion of the
section by the wire C; F is the detached portion of the section. connected to
said section by the wire F; D' G are detached portions of sections D and G
connected to their respective sections through the wires G³ and D2; and N N are
insulating blocks, which separate, the ends of the respective sections. and their
detached portions.
In Figure 3 the car is shewn with all its contacts touching the main parts CD
of the track sections and the motor H³ is receiving current from the mains E¹ M
through the track section C which is connected to main M through the electro-
magnetic switch C.
In Figure 4 the car is shewn as having advanced a short distance so that its
foremost collecting shoes I I¹ are in contact with the detached parts F³ G¹ of the
sections FG. In this position the battery H will be sending current through the
bars F G and bars FG to the coil F which operates the magnetic switch F.
The car motor H³ will still be receiving current from the track section C through
the shoes J K L.
In Figure 5 the car is in a position, where the foremost shoes I 1¹ have just
come into contact with the detached portions C* D' of the track section C D. The
battery H will, however, be sending current through the shoes J J, K K' and
track sections F G and F G to the coil F so that the electroinagnetic switch
will, still be in circuit. The car, motor H' will be receiving current through the

page_text: shoe I which is in contact with the track section C connected by wire C to
track section C and also through shoe H which is still in contact with track
section ().
In Figure 6 the ear is shewn with its foremost shoes II' in contact with the-
track sections FG if now the electromagnetic switch F has had time to operate-
the car motor H3 will be receiving current through the contact shue I, the track
section F and switch F' from the main M. If the switch has not operated the car
battery H' will be supplying current to the coil F through the medium of track
sections F and G in order to operate said switch, while the car motor will be
receiving current through the shoes J K and track section C, wire C and switch C.
This state of affairs will prevail until the car has moved so far that the rearmost
contact shoes L 1' are leaving the detached track sections (D². It will be-
observed, therefore, that the time allowed for the switch F to operate is equal to
the time taken by the car to travel from the position where the foremost shoes I P
leave the main track sections C D to the position in which the rearmost contact
shoes L L' leave the detached track sections CD. It will be readily understood
that the length of the detached sections C D F G must be a little less than the-
distance between the foremost shoes I I¹ and the rearmost L L'. Hence the
switch F is being operated during the whole time that the car is travelling
approximately four times its own length, that is to say, taking a car 30 feet long
running at 60 miles an hour as in the example above mentioned the time allowed
for the switch to operate would be considerably over one second in duration.
The car in the drawings is shewn with four sets of contact shoes and the short.
parts of the track sections are illustrated as being approximately equal in length
to the distance between the foremost and rearmost shoes carried by the car. It is.
obvious, however, that the number of shoes can be varied and the dimensions of
the detached parts of the track sections can also be varied the relative dimensions.
being such that at the maximum speed of the car the electromagnetic switch shall
have time to operate while the car is moving from the position shewn in Figure 3.
to that in which the rearmost contact shoe is entering the middle portion of the
track section in front. The number of contact shoes and the distances apart should
be so arranged that when one of the contacts is touching a detached portion of the
section some other of the shoes must be touching one of the adjacent lengths of the
track section.
In some railways constructed according to the abovementioned system only one
fixed track section is required, the coil marked C F in Figure 3 for example
being excited by the main current. In these cases the arrangement of the detached
portions of the sections will be the same, the car of course having one contact shoe
instead of two in each set.
In other systems more than two sets of contact rails are provided but it is clear
that the same principles of construction may be followed.
My invention may be considerably varied in detail and I reserve the right to
make alterations that may be desirable in the relative lengths of the fixed and
moving contact bars.
My invention is also applicable to systems wherein trains of cars are used
propelled by electric locomotives on either or both ends of the train as well as to
those systems wherein single cars only are used.
Having now particularly described and ascertained 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. For electric cars operated as herein described, a collecting bar or shoe which
is wider at its middle portion than at its ends, for the purpose specified.
2. In an electric traction system of the class described, the provision of fixed
track sections having their ends overlapping and extending side by side for some,
distance so that the collecting bar carried by a car will touch both sections at one
time, substantially as and for the purpose specified.

page_text: 3. In an electric traction system of the class described, the division of the fixed
track sections into three or more parts, one or more parts of one section being
interposed between the parts of the adjacent track sections, for the purpose
specified.
4. An electric traction system constructed and operating substantially as described
with reference to Figures 3 to 6 of the accompanying drawings.
10th 1 of 1907
W. P. THOMPSON & Co.,
Of London, Liverpool, Manchester, and Birmingham,
Patent Agents for the Applicant.