Improvements in Apparatus for Controlling or Regulating the Speed of Railway Rolling Stock and Stationary and other Engines.
Year: 1891

page_text: Date of Application, 9th Dec., 1891-Accepted, 27th Feb., 1892
COMPLETE SPECIFICATION.
Improvements in Apparatus for Controlling or Regulating the
Speed of Railway Rolling Stock and Stationary and other
Engines.
I, GEORGE FREDERICK REDFERN, of the firm of G. F. Redfern & Co., The
General Patent Office, No. 4, South Street, Finsbury, in the County of Middlesex,
Patent Agents, do hereby declare the nature of this invention (a communication
to me by Amandus Gustav Robert Kreitling, Gentleman, and Friedrich Eduard
Max Kreitling, Engineer, both of 9, Marheimkeplatz, Berlin, in the Empire of
Germany) 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 mainly to apparatus for controlling or regulating the speed
of railway rolling stock.
The greater number of the accidents which happen on railways are traceable to
the proper speed being exceeded. The attempts which have hitherto been made.
to avoid these evils arising from the proper speed being exceeded have however
been made upon the wrong lines, since they employ not direct means but indirect
ones to obviate the source of the danger by providing the driver of the locomotive
with means for controlling the speed.
These controlling arrangements consist of automatic speed measurers which
indicate correctly the variations of speed upon the journey, and so furnish
opportunity for seeing, after the journey is ended, whether the driver of the
locomotive has at any time exceeded the prescribed speed, which is known to him,
but do not prevent the driver of the locomotive from exceeding the prescribed
speed.
The prescribed rate of travel may however be exceeded from the most varied
causes which are not always the fault of the engine driver. For instance, the
engine driver being suddenly taken ill, or meeting with an accident during the
journey may have an effect upon the proper driving of the train, so that
the prescribed rate of travelling is exceeded. If however the proper speed be
exceeded a dangerous condition of affairs at once arises, and it is a piece of good
fortune if an accident, for which opportunity is thereby afforded, does not actually
happen.
Should the rate of travel be intentionally increased by the engine driver beyond
the prescribed amount, in order to make up for a loss of time, as long as the engine
remains under the control of the driver, an experienced and careful one will usually
be able to avoid the occurrence of an accident.
Should the driver however lose consciousness, as soon as the dangerous condition
to which he has given rise brings an accident near, or if from any other circum-
stance he should lose control of the rate of travelling, any apparatus for recording
the latter becomes utterly useless, and an accident with more or less serious
consequences will occur. These disadvantages, which still exist in the driving of
locomotive engines, it is the object of the above mentioned invention to remove,
and this is attained by causing the speed of travel, as soon as it has reached a
certain point, to set in action a brake apparatus, which remains in action until the.
moving force of the train is so far reduced that the prescribed speed can no longer
be exceeded. The purpose of this invention is fulfilled by means of a force
accumulator, connected with any one of the axles of the wheels, the force reaching
such an amount, when the prescribed speed of travel is overstepped that the brake
apparatus connected with it is set in action.

page_text: Figure 1 is an elevation and
Figure 2 is a transverse section illustrating one way of constructing the new
speed regulator in which a hydraulic press is made to act as the force
accumulator.
The piston of the pump P is connected with one of the axles of the locomotive
so that the pump, by means of its suction and pressure valves contained in a casing,
withdraws fluid from the vessel G, and transfers it to the pressure cylinder O.
The vessel G is situated beneath the bed-plate of the pressure cylinder, secured to
the engine in any suitable manner, and filled with a fluid which freezes with
difficulty or not at all, as for instance glycerine.
The piston K, which is packed and loaded, reaches into the pressure cylinder O,
and is connected by a system of links or of levers x, y with a brake apparatus.
The loading of the piston causes the latter to return, and at the same time takes
off the brake, and is effected, in the construction shewn, by the spiral spring F.
From the side of the pressure cylinder O passes a tube, whose capacity can be
controlled by a screw valve A, Figure 1, or by some equivalent contrivance, and
this tube passes back to the receiver G, so that the fluid driven back from the
pressure cylinder by the pump P can flow back into the receiver G.
If the screw valve A be now so set that the quantity of fluid which is driven by
the pump P into the pressure cylinder at a given rate of travelling, can escape
through the screw valve A without pressure, the apparatus will in this case work
independently, being thus constantly tested as to its readiness for work, but giving
rise to no action of the brake apparatus.
As soon however as the prescribed limit of speed is reached, and the activity of
the pump thus increased, more fluid will be transferred to the cylinder O than can
escape in the same time through the screw valve. As the result of this a hydraulic
pressure will be brought to bear upon the piston K, which at the proper dimensions
in diameter of the latter is strong enough to operate the brake mechanism and so
diminish the speed of the engine.
As the speed of the engine is decreased a diminution of the activity of the pump
at once occurs, and the latter drives no more fluid into the pressure cylinder C than
can escape without pressure through the screw valve A. The pressure upon the
piston K thus ceases, the spring F which loads it then presses it down again, and
the brake mechanism is released.
The whole apparatus is, it need hardly be said, so arranged, or so surrounded by
a casing, that no unauthorised person can obtain access to it to put it out of action
or to interfere with the setting of the screw valve.
When such an apparatus is made use of it is quite impossible that the prescribed
rate of travelling should be exceeded, even if the driver intends to do it.
Since, again, the apparatus comes into action at the moment when the prescribed
rate of travelling is exceeded, it cannot happen that the vis viva of the train
becomes so great in consequence of an increased speed of travelling that the engine
driver ceases to be able to decide the time which will elapse between the application
of the brakes and the stopping of the train and enters terminal stations with too
great a velocity, and so gives rise to accidents. The precise method of carrying
out the hydraulic arrangement can of course be varied at will, for instance, the
pressure cylinder O and piston K with its spring F might be replaced by a
diaphragm acting as a spring, as in the pressure gauge, and closing a receiver.
The diaphragm which acts as a spring would then of course be connected with the
brake mechanism in a suitable manner. It is also possible to replace the fluid by
air or gas..
In order to avoid the possibility of the bursting of the pressure cylinder O under
too great hydraulic pressure it is advantageous to apply a slide valve S in the
pressure cylinder O, this valve being provided with a slot in which the disc shaped
end of the piston K engages. As the piston K. rises it carries the slide S with it..

page_text: and opens a vent as soon as it has set the brake apparatus in action, so that
when the piston sinks down again the fluid can escape rapidly from the pressure
cylinder.
In order to be able to set the screw valve easily at any required point it is
advantageous to furnish it with an index which shews on a scale the position of the
head of the valve and at the same time the width of the valve opening.
The above described speed regulator can also be applied with advantage to
stationary engines of all kinds in which it is desired to ensure that a prescribed
speed shall not be exceeded. It may then be caused to release a brake or as in the
case of prime movers to regulate the inflow of steam, or to effect at one and the
same time the application of a brake and the cutting off the motive force.
The action of the apparatus is the same in all cases.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. A speed regulator for locomotives consisting of the application of an
accumulator of power, to the engine, which is connected with a brake mechanism,
and is so set in action by the driving axles that it sets the brake mechanism in
action only when the prescribed speed is exceeded, and automatically reduces the
rate of travelling, for the purpose of preventing the prescribed rate of travelling
from being under any circumstances exceeded.
2. In a speed regulator such as is claimed in the first claiming clause the
employment as an accumulator of power of a hydraulic or pneumatic press, P, O,
the pressure cylinder O of which is provided with an outlet, the carrying capacity
of which can be so limited by a cut off valve that the pressure in the pressure
cylinder only reaches such a point as to set the brake mechanism in action when
a certain rate of travelling is reached and the pump thereby increased in
activity.
ו.ית
1
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.