Improvements in Electric Locomotives.
Year: 1892

page_text: Date of Application, 22nd June, 1892-Accepted, 23rd July, 1892
COMPLETE SPECIFICATION.
Improvements in Electric Locomotives.
We, FREDERICK PURDON and HARRY ERNEST WALTERS, both of 2 Great
George Street, Westminster in the County of Middlesex, Civil Engineers, BASIL.
MOTT of 83 Kimberley Road, Clapham in the County of Surrey, Civil Engineer,
and JOHN PATRICK O'DONNELL of 2 Great George Street, Westminster in the
County of Middlesex, Civil Engineer, do hereby declare the nature of this inven-
tion and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement :-
Our invention consists of improvements in electric locomotives suitable for hauling
vehicles upon a track provided with two rails upon which the carrying wheels of
the locomotive run and also one rail of special type placed parallel to the other two
and either midway between them or at some convenient position between them.
We prefer usually to place our third rail midway between the other two rails. The
special track alluded to above is described in detail in the Specification of Letters
Patent granted to the said Frederick Purdon, Harry Ernest Walters, Basil Mott
and John Patrick O'Donnell, No. 13351 dated August 7th 1891.
The objects of our improvements are to enable permanent way to be laid with
curves of smaller radius than those at present in use, for by means of our invention
we enable the locomotive to pass easily round such curves and avoid the destructive
side strain upon the flanges of the ordinary locomotive wheels when engines of the
Another feature of our
usual type are passing round curves of small radius.
invention is that we are enabled to work our electric motors more efficiently as we
avoid the excessive waste which now occurs in the resistance coils used for the
motors. In order to make this point perfectly clear we will briefly describe the
present practice in electric locomotives. In order to obtain the highest efficiency
a motor must be run at a high speed and if the driving axle of the locomotive is
not required to rotate at such a speed it has been usual to reduce the rate of rota-
tion by means of special gearing. Owing to the frequent jars felt in the vehicle
at starting and stopping and owing also to inequalities in the track, the life of such
gearing has been very short, and many different types of teeth have been
brought out and many different materials used to lessen the disastrous results
alluded to.
In our engine we do not employ toothed gearing at all.
Another difficulty has proceeded from the necessity of starting the motor from
rest. When the armature of a motor is at rest if the full electro-motive force of
the supply were to be switched on such a large current would flow through the
coils that they would be at once "burnt out," that is to say, the insulation wouli
be totally destroyed. In order to avoid this result it has been usual, in all cases
whether the motor was coupled by gearing to the driving axle or placed direct
upon the axle itself, to provide special resistance coils which serve the purpose
of diminishing the electro-motive force between the terminals of the motor. It
is however obvious that the safety of the armature coils is obtained at the
expense of great waste of power as the electric energy used in the resistance coils
is dissipated in the form of heat and wasted. Our object has been to eliminate
this source of loss by running our motors always at a high speed whether the vehicle
is at rest or travelling and we provide friction gearing which enables us to allow
the motor either to run idle or to drive the car.
The design of our locomotive is such that while in all cases we obtain a driving
power upon the third or central rail we may or may not also apply a driving
power to the vertical wheels which support the weight of the car itself. In cases
where there are steep gradients upon the railway it is advisable to drive upon the

page_text: horizontal wheels acting upon the central rail and also upon the vertical wheels
which carry the framework of the engine itself.
We shall only describe the form of locomotive in which driving is effected by
means of the action of horizontal wheels upon the central rail. This type of loco-
motive we have shown without flanges upon the vertical or carrying wheels as it
is obvious that side play is prevented by the action of the horizontal driving wheels.
Flanges may however be used in all cases and are recommended in cases where
the vertical wheels are also driven as in this way the engine will keep the track
properly even when the central rail wheels are out of gear altogether.
The ordinary framework of the locomotive carries a frame so constructed as to
support the ends of the vertical driving shafts. The horizontal wheels are arranged
in two or more couples as may be desired. The shafts upon which the horizontal
driving wheels are fixed are carried and supported by the cross framing in which
are placed bearings. The frames of the engine also carry the lower bearings for
these shafts. Between the horizontal driving wheels are placed electric motors
with their armature shafts vertical and supported in suitable bearings at top and
bottom. At the lower end of each armature shaft is placed a suitable wheel and
between each of these wheels and the actual driving wheels friction wheels are so
arranged that the motor wheels may be caused to actuate the horizontal driving
wheel or not as need may be. In order to start or stop the engine gearing is
arranged by means of which the friction wheels placed between the motors and rail
driving wheels may be moved in and out of gear.
In order that our invention may be more clearly understood we will now describe
it with reference to the accompanying drawings in which similar letters refer to
similar parts throughout the different views.
Figure 1 is a longitudinal elevation of the electric locomotive.
Figure 2 is a plan partly in section, the left half showing the guides attached to
the frame and carrying the bearings of the motors and driving wheels, the right
half showing the guides attached to the main framing of the locomotive and
carrying the bearings of the friction wheels and the gearing for actuating the same.
Figure 3 is a vertical sectional elevation on the line A-A Figure 2.
Figure 4 is a vertical sectional elevation on the line B-B Figure 2.
Figure 5 is a plan of Figure 1 from above.
a, a, are the frame plates of the engine, b, b, are the vertical carrying wheels
preferably without flanges, c, c, are the ordinary axle boxes upon which the load
is borne.
The frames a, a are provided with foot plates d in the usual manner, and two
pairs of arched girders e, e, are so arranged as to carry the bearings of the various
shafts. f,, are the ordinary carrying rails and 9 is the central rail upon which
in this case all the driving power is exerted. h, h, are the motor shafts of which
four are shown in the engine illustrated; these shafts are carried at the top in
bearings i, i, provided with collars such as are used with thrust-blocks in order to
carry the load and these bearings are supported upon the arches e, e. The shafts
carry the small wheels k, k, at the bottom and are carried in suitable bearings l
which are rigidly connected to the cross stays j, j. The three vertical shafts m, m, m,
are each carried at the top in a bearing n which is itself borne upon trunnions so
that each shaft m can swing like a pendulum at right angles to the central rail.
A wheel o is fixed to each of the shafts m at the bottom and acts as the driving
wheel upon the central rail. The lower end of each shaft m is carried in a
bearing which is free to slide between the cross bars 7 and a spiral spring r is
adjusted so as to give a certain initial thrust upon the wheel o, this thrust acting
upon each of the six wheels o keeps the locomotive perfectly central upon the
track.
A pair of friction wheels s, s, is provided for each motor wheel h. These are
carried upon pins shown in Figure 3 and are free to slide in guides, each pair is
controlled by a laminated spring t. The method of adjusting the friction wheels
is by means of the hand wheel u, this actuates a horizontal shaft upon which

page_text: are keyed bevel wheels, Figure 1, which drive vertical shafts w, w, and actuate the
bevel wheels a, x, and thus enable the friction wheels s, s, to be drawn tightly
between the wheels s and o or freed from them altogether.
h, h, are the first motion shafts and each carries an armature not shown in the
figures and the field magnets are suitably arranged so as to surround the armatures.
It is thus obvious that one or more of the armature shafts h may be caused to.
rotate and by means of the wheels s power will be transmitted to the driving
wheels o and thence to the central rail
9.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is --
1. In electric locomotives arrangements for operating horizontal driving wheels.
through vertical motors which are themselves put in motion before the engine is
started from rest, substantially as herein described and as illustrated in the
accompanying drawings.
2. In electric locomotives the application of friction gear for driving horizontal
wheels in contact with a special rail, substantially as herein described and as
illustrated in the accompanying drawings.
3. In electric locomotives the provision of springs in connection with the hori-
zontal driving wheels to provide for their adjustment in rounding curves, substan-
tially as herein described and as illustrated in the accompanying drawings.
4. In electric locomotives the provision of springs for normally forcing the
friction wheels into gear with the driving wheels the said friction wheels being
forced out of gear when necessary by bevel wheels and shafting, substantially as
herein described and as illustrated in the accompanying drawings.
5. In electric locomotives the arrangement of the bearings in connection with
shafts upon which the driving wheels are fixed the said bearings being provided
with trunnions so that the shaft may have a pendulum movement at right angles
to the central rail, substantially as herein described and as illustrated in the
accompanying drawings.
6. In electric locomotives the transmission of power from a motor running with
its armature vertical and carried in fixed bearings, by means of a movable friction
wheel operating in the manner substantially as herein described and as illustrated
in the accompanying drawings.
7. In electric locomotives arrangements for supporting the said movable friction
wheels and acting upon them by means of springs and releasing them by means
of shafts and gearing, substantially as herein described and as illustrated in the
accompanying drawings.
8. In electric locomotives the arrangement of sliding bearings and springs by
which the driving wheel is held in adjustable contact with the central rail,.
substantially as herein described and as illustrated in the accompanying drawings.
Dated this 22nd day of June 1892.
JOHN P. O'DONNELL,
2, Great George Street, Westminster, London, S.W.,
Agent for the said Applicants.