IMPROVEMENTS IN MACHINERY FOR PROPELLING AND STOPPING VEHICLES ON TRAMWAYS
Year: 1876

page_text: LETTERS PATENT Henry Percy Holt, of Royal Insurance Buildings, Leeds, in
the County of York, Civil Engineer, for the Invention of "IMPROVEMENTS IN
MACHINERY FOR PROPELLING AND STOPPING VEHICLES ON TRAMWAYS."
Scaled the 28th November 1876, and dated the 7th June 1876.
PROVISIONAL SPECIFICATION left by the said Henry Percy Holt at the
Office of the Commissioners of Patents on the 7th June 1876.
HENRY PERCY HOLT, of Royal Insurance Buildings, Leeds, in the County of
York, Civil Engineer. "IMPROVEMENTS' IN MACHINERY FOR PROPELLING AND
STOPPING VEHICLES ON TRAMWAYS."
The first part of this Invention consists in the use of a small auxiliary engine to
drive the car wheels when ascending inclines, which may be fixed either on the
locomotive or on the car (as may be more convenient), this engine being arranged
to run at a higher piston speed than the locomotive engines. When the auxiliary
engine is fixed on the car it is thrown out of gear by an automatic coupling on
levels when steam is shut off, and thrown into gear when steam is admitted to the
cylinder for mounting gradients.
When the auxiliary engine is fixed on the locomotive a hand clutch coupling
may be used for the above purpose.
The second part refers to an arrangment for mixing the exhaust steam and
products of combustion from the fire with a large volume of heated air, and may be
carried out as follows:-The boiler is surrounded by a jacketed space through
which air is drawn by means of jets of exhaust steam, working into the chimney
flue through one or more sets of louvres in which the air and steam are thoroughly
mixed together, the exhaust steam is taken from a chamber into which the cylinders
exhaust under a back pressure which is maintained by an automatic valve to the
required pressure to induce the current without noise. In some cold climates, in
lieu of the above I exhaust into strong receivers containing water, pumping as
much steam as possible back into the boile, and allow the pressure to accumulate
and blow off when required. The water is renewed at the stoppages when
required.
The third part refers to an arrangment of buffer for regulating the distance
between the engine and the car, and connecting the buffer slide with the ordinary
brake handle shaft by means of chains passing over suitable pulleys, so that when the
Price fid 7

page_text: engine and car come in contract with above a given amount of force (regulated by
an adjustable spring) the brake is applied to the car wheels according to the intensity
of that force.
In some cases in lieu of the above buffer break I use a steam cylinder with
suitable valves, piston, or plunger, fixed on the engine and connected by means
of chains with the ordinary car hand brakes for applying the brakes simultaneous
to both locomotive and car.
The fourth part of this Invention consists in using liquid fuel for increasing the
power of an "accumulative" boiler, that is, a boiler with large water capacity and
small beating surface in order to avoid the nuisance of smoke and dust, or when
the reduction of weight is an object of importance an ordinary boiler may be heated
in the same manner, provided with a self-acting steam valve to shut off a portion
of the supply of fuel when stoam is raised more quickly than required.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Henry Percy Holt in the Great Seal Patent Office on the 7th
December 1876.
HENRY PERCY HOLT, of Royal Insurance Buildings, Leeds, in the County of
York, Civil Engineer. "IMPROVEMENTS IN MACHINERY FOR PROPELLING AND
STOPPING VEHICLES ON TRAMWAYS."
The first part of this Invention consists in using a second or auxiliary engine or
engines to assist the ordinary engines when ascending inclines, which engine may
be fixed either on a separate locomotive or on the car itself (as may be the more con-
venient), this engine being arranged to run at a higher piston speed than the
ordinary engine, hence when the ordinary engines are running slowly in ascending
gradients the auxiliary engine has sufficient piston speed to develope the extra
power required to overcome the increased work together with the decreased piston
speed of the ordinary engines. The auxiliary engine is coupled to the driving
wheels of either the locomotive or the car, so that when not required it can be
thrown out of gear in order to lessen wear and tear and friction when running on
levels. The auxiliary engine may be thrown in or out of gear either by ordinary
friction, or clutch blocks, or wheels, worked by hand or by power pistons or
plungers actuated by the motive pressure. In some cases the throwing into gear
is accomplished by the extra drag on the coupling between the locomotive and the
car when ascending inclines, the same being regulated by adjustable springs.
When the auxiliary engine is fixed on a separate locomotive in some cases the
weight of the locomotive is insufficient to give adhesion for utilizing the whole
driving power, I then employ the arrangements described in a Specification,
No. 1581, filed in accordance with Letters Patent granted to me on the Thirteenth
day of April, 1876, for transmitting power from the auxiliary engine to the wheels of
the car itself in order to provide sufficient adhesion for utilizing this additional
driving power.
I may here mention that the driving chain or band requires to run at a velocity
exceeding that of the tram car and locomotive.
Pressure may be admitted to auxiliary cylinders by means of ordinary regulators.
The second part of this Invention consists in an arrangement for mixing the
exhaust steam and the products of combustion from the fire with a large volume
of heated or dry air, in order that the same may be absorbed and thus rendered
noiseless, invisible, and unobjectionable. This may be carried out as follows:-
The boiler is surrounded by a jackett between which and the boiler a space is
arranged, thro' which air is drawn in by means of jets or annular nozzles of
exhaust steam and blown into the smoke box or chimney flue thro' several
annular nozzles or louvres. This exhaust steam is taken from a receiver into which

page_text: the engine exhaust under back pressure which is maintained nearly constant by
means of a spring escape valve the requisite pressure to induce the current
without noise.
The blast for the fire is obtained by the use of a separate adjustable exhaust
nozzle, or by inducing the products of combustion through some of the annular
induction nozzles or louvres.
In some cold climates in lieu of the above I exhaust part of the steam into strong
steain-tight receivers containing water, pumping as much steam and hot water back
into the boiler as possible, and allow the pressure to accumulate and blow off by
means of valves in suitable places when required, the other part I use to obtain the
chimney draught by passing it under constant back pressure from the exhaust
receiver through annular adjustable nozzles in the smoke box or chimney, as
described in the second part of this Invention.
The third part of this Invention refers to an arrangement of spring sliding buffers
for regulating the distance between the locomotive and the car which can be
adjusted, the buffer sliding part being connected by means of chains passing over
suitable pulleys with the ordinary hand brakes shafts on the car, so that when the
locomotive and car come in contact with a force exceeding the strength to which
the spring is adjusted, the buffer is forced home into the slide and the car brakes
put on automatically with a force due to the retarding power of the locomotive,
also when the locomotive engine overruns the car the spring takes the brakes off
again automatically.
In some cases in lieu of the above-named buffer brake I use a steam cylinder
with ordinary suitable valves, pistons, or plungers, fixed either on the engine or
on the car for applying the locomotive and car brakes either separately or simul-
taneously, but I prefer to fix the cylinder on the engine and connect the same
direct to the locomotive breaks, and couple up to the ordinary car breaks by means
of central chains or rods and thus apply the breaks simultaneously to both the
locomotive and the car.
In some cases I connect any ordinary suitable form of steam engine governor to
admit pressure by means of any ordinary valve or cock to the break cylinder above
named to apply the brakes whenever the speed run exceeds that to which the
governor is adjusted, in which case the power of the cylinder is likewise used to
close the locomotive engine regulator by incans of a chain passing over pulleys con-
nected to the engine break levers.
"
The fourth part of this Invention consists in using liquid fuel for increasing the
power of an
accumulative boiler" (that is, a boiler with large water capacity and
small heating surface) in order to avoid the nuisance of dust, or when the reduction
of weight is important an ordinary boiler may be heated in this manner.
The fuel is blown into the firc-box in the form of spray by means of jets of air
under pressure (obtained from pumps, fans, or blowers, as may be the more con-
venient) passing over the surface of the fuel; this comes in contact with a torch of
any convenient kind, such as coke or asbestos when it is ignited.
The liquid fuel may be contained in a tank, the amount of fuel and air admitted
into the fire-box being regulated by the pressure of the steam in the boiler through
the medium of a loaded diaphragm or piston under the control of an adjustable
spring which is set to the boiler working pressure, any variation of which by this
means closes or opens the air and fuel valves as the case may be.
In order that my Invention may be more clearly understood I will now refer to
the Drawings in which the letters represent the following parts :-