Improvements in and connected with Motor-driven Velocipedes and other Light Vehicles.
Year: 1899

page_text: Date of Application, 30th May, 1899
Complete Specification Left, 28th Feb., 1900-Accepted, 14th Apr., 1900
PROVISIONAL SPECIFICATION.
Improvements in and connected with Motor-driven Velocipedes
and other Light Vehicles.
I, HIRAM STEVENS MAXIM, of 18, Queen's Gate Place, in the County of
Middlesex, Chevalier of the Legion of Honour, Civil and Mechanical Engineer,
do hereby declare the nature of this invention to be as follows:-
This invention relates to motor driven velocipedes and other light vehicles.
Previous attempts to construct motor driven velocipedes have been generally
unsatisfactory. In nearly every case the motor employed has worked on the
Otto principle in which only one stroke in four is a working or impulse stroke,
so that a high piston speed has been requisite and consequently motion-reducing
gearing of more or less complication has had to be interposed between the motor
shaft and the driving wheels.
The object of my invention is to simplify the construction and reduce the
number and weight of the parts employed so that a very light vehicle can be
constructed.
In order to accomplish this object I provide a suitable frame with a front
steering wheel and two rear driving wheels placed on the same axle with only
sufficient space betwen them for a suitable crank and an eccentric or other
device for working the valve gear of the engine. By reason of the rear wheels
being arranged in this close proximity the vehicle may be ridden and steered
like a bicycle, and when travelling round a curve, only one of the rear wheels
will be in contact with the ground. Nevertheless the distance apart of the two
rear wheels will be sufficient to enable the rider to balance himself with facility
when stopping, and to allow the machine to maintain an upright position on
level surfaces when not being ridden.
For driving the vehicle I employ a special form of gas engine connectedl
directly to the crank shaft or axle of the driving wheels. This engine has one
long cylinder (or two short ones arranged coaxially), and is provided with two
pistons mounted on the same rod. Between the two pistons is arranged a cross
head, to which I couple a forked rod connected with the crank. One of the
pistons, which may be somewhat larger than the other, constitutes the working
piston and the other acts as a pump piston which at each working stroke of the
engine, forces air into a reservoir and compresses it therein. This reservoir is
carried by the aforesaid frame of the vehicle and may form the pedestal or main
support for the cylinder with the larger portion of which it communicates through
an appropriate pipe or passage controlled by a suitable admission valve.
The air in its passage through the reservoir and into the cylinder is brought
into contact with a suitable hydrocarbon such as light petroleum, generally
known as naphtha, of a specific gravity of about 72° Beaumé.
This light
petroleum may be placed in a separate chamber or in the reservoir itself. Petro-
leum of the kind mentioned, supplies the air with the requisite amount of
vapour to make it combustible. The engine does not work explosively, but is

page_text: provided with an ignition tube or electric apparatus which ignites the combustible
charge as soon as the admission valve is opened and maintains the flame in
the cylinder until the valve is closed. There is therefore no explosion, and
the pressure in the cylinder is not intended, at any time, to greatly exceed the
pressure in the aforesaid reservoir. An appropriate discharge valve is provided
for the escape of the products of combustion from the working cylinder. An
engine of this kind does work at every outward stroke of the piston and may be
run at any desired speed.
I prefer in some cases that the working cylinder should be made of, or lined
with, refractory material, such as porcelain or some refractory and nonconducting
material, such as a mixture of clay, silica and plumbago, which is very hard
and withstands a high temperature. Or I may employ an inside nickel cylinder
and an outside iron cylinder, with asbestos interposed between them. I also
prefer to cover the head of the cylinder, or parts thereof, and the inner end
of the piston, with a similar substance.
I am thus enabled to maintain a high temperature inside the cylinder, and
prevent radiation of heat therefrom. The engine is in fact a hot air engine, the
air being heated by the burning of the combustible material with which it
is impregnated. By maintaining this high temperature in the cylinder
use a very much weaker mixture of petroleum vapour and air than is necessary
where the cylinder is kept cool by water.
can
In order to obtain the requisite initial pressure of air in the aforesaid reservoir,
an ordinary inflator pump can be employed and when a pressure of from 20
(twenty) to 40 (forty) lbs. to the square inch has been attained therein, the
rider may mount the vehicle and (if the cranks have previously been placed in
the proper position) by merely opening the aforesaid admission valve start the
motor to work, assuming of course that the ignition device has been previously
rendered active. I thus avoid the necessity of using pedals, sprocket wheels,
driving chain and similar gearing, which are required for ordinary motor veloci-
pedes and thereby greatly simplify the construction.
Another advantage of this form of motor vehicle is that the brakes for the
wheels may if desired be dispensed with, because by shutting the passage or
valve between the aforesaid reservoir and the working cylinder the pump will
continue to compress air in the reservoir and so absorb sufficient energy to retard
the speed of th vehicle. To prevent the pressure of the air in the reservoir
rising too high a relief valve may be provided either on the reservoir or on the
pump.
As the density of any mixture of air and hydrocarbon varies very much, both
on account of the specific gravity of the hydrocarbon and of the temperature
of the air, it is necessary to use a hydrocarbon that will give to the air rather
more vapour than is necessary to make it combustible, the strength of the charge
of vapour being afterwards reduced by allowing some of the compressed air to
pass direct to the working cylinder and enter therein with the said air and vapour.
For this purpose I may provide a pipe leading from the pump cylinder and
controlled by a suitable valve which may be operated by hand.
In an engine of this kind it is desirable to employ a considerable volume of
combustible mixture for the working charges and therefore it is advisable to
interpose between the working cylinder and the reservoir some means for pre-
venting the combustible mixture when burning in the cylinder, from "lighting
back and so causing an explosion of the reservoir. In order to guard against
such an accident, I prefer to employ one or more non-return valves and also to
pass the combustible mixture through a chamber or tube which may be either
packed with wire gauze, small pieces of iron, or wires. Or said chamber may
contain some material which will be decomposed in case the flame should light
hack and enter the chamber, the decomposition giving off gases which would
extinguish the flame and thus prevent its reaching the reservoir.
Or I may
provide a fusible plug so arranged that in the event of the device employed for

page_text: preventing the lighting back becoming over heated the said plug will melt and
give relief to the combustible gases.
When the motor-vehicle is working continuously on a long journey, it is not
necessary to use an igniter for firing the charges admitted to the working
cylinder as the interior of the latter will become sufficiently heated to ignite
the combustible mixture and to maintain the combustion while the admission
valve is open.
In order that the pump cylinder shall be cheap and simple to construct and
noiseless in operation, I propose in some cases to use flap valves of india-rubber
similar to those employed in air-pumps for steam engines or in blowers for
church-organs. To overcome the liability of the india-rubber to be attacked by
the oil employed to lubricate the piston, I use a special oil which I have provided
for the purpose, but which however forms no part of the present invention.
Dated this 30th day of May 1899
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.
Improvements in and connected with Motor-driven Velocipedes
and other Light Vehicles.
I, HIRAM STEVENS MAXIM, of 18, Queen's Gate Place, in the County of
Middlesex, Chevalier of the Legion of Honour, Civil and Mechanical 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:-
This invention relates to motor driven velocipedes and other light vehicles.
Previous attempts to construct motor driven velocipedes have been generally
unsatisfactory. In nearly every case the motor employed has worked on the
Otto "principle in which only one stroke in four is a working or impulse stroke,
so that a high piston speed has been requisite and consequently speed-reducing
gearing of more or less complication has had to be interposed between the motor
shaft and the driving wheels.
The object of my invention is to simplify the construction and reduce the
number and weight of the parts employed so that a very light and cheap vehicle
can be constructed.
In order to accomplish this object I provide a suitable frame with a front
steering wheel and with two rear driving wheels mounted on the same axis and
in close proximity to each other, that is to say with only sufficient space between
them to receive a suitable crank and an eccentric or other device for working
the valve gear of the engine. By arranging the rear wheels in this close
proximity to each other, the vehicle may be ridden and steered like a bicycle,
and when travelling along a curve, usually only one of the rear wheels will be
in contact with the ground. Nevertheless the distance apart of the two rear
wheels will be sufficient to enable the rider to balance himself with facility when
stopping, and to allow the machine to maintain itself in an upright position on
a level surface.
For driving the vehicle I employ a gas engine connected directly to the afore-
said crank shaft or axle of the driving wheels. This engine has one long
cylinder (or two short ones arranged co-axially), and is provided with two pistons

page_text: mounted on the same rod. This rod is coupled to the crank by a forked or
bifurcated connecting rod pivotally joined to the piston rod at a point between
the two pistons. One of the pistons is of larger diameter than the other and
constitutes the working piston, the other or smaller one acting as a pump piston
which at each working stroke, forces air into a cylindrical container or reservoir
and compresses it therein. This reservoir is carried by the aforesaid frame of
the vehicle and may form the main support for the engine. The said reservoir
communicates with the working cylinder through an appropriate pipe or passage
controlled by a suitable admission. valve or valves. Preferably the said reservoir
forms part of the backbone of the vehicle when it is constructed like a velocipede.
The air in its passage through the reservoir and to the cylinder is brought into
contact with a suitable hydrocarbon such as light petroleum, generally known
as naphtha, of a specific gravity of about 720 Beaumé. This light petroleum
may be placed in a separate chamber or in the reservoir. The engine is not
intended to work explosively, but is provided with an ignition tube or electric
apparatus which ignites the combustible charge as soon as the inlet valve is
opened and maintains the flame in the cylinder until the valve is closed. There
is therefore no explosion of the charge within the cylinder, and the pressure in
the cylinder is not intended, at any time, to greatly exceed the pressure in the
aforesaid reservoir. An engine of this kind does work at every outward stroke of
the piston and may run at any desired speed.
In order to obtain the requisite initial pressure of air in the aforesaid
reservoir, an ordinary hand pump can be employed and when a pressure of
from 20 (twenty) to 40 (forty) lbs. to the square inch has been attained therein,
the rider may mount the vehicle and (if the crank has previously been placed in
the proper position) by merely opening the aforesaid admission valves, start the
motor to work, assuming of course that the ignition device has been previously
rendered active. I thus avoid the necessity of using pedals, sprocket wheels,
driving chain and similar gearing, which are required for ordinary motor
velocipedes and I thereby simplify the construction.
As the density of any mixture of air and hydrocarbon vapour varies very
much, both on account of the specific gravity of the hydrocarbon and of the
temperature of the air, it is necessary to use a hydrocarbon that will give to the
air rather more vapour than is necessary to make it combustible, the strength
of the charge of vapour being afterwards reduced by allowing some of the com-
pressed air to mingle with it as it passes to the working cylinder. This can be
effected by regulating the aforesaid admission valves as will be hereinafter fully
explained.
In an engine of this kind it is desirable to employ a considerable volume of
combustible mixture or the working charges and to interpose between the work-
ing cylinder and the reservoir some means for preventing the combustible mixture,
when burning in the cylinder, from "lighting back" and so causing an explosion
of the reservoir. In order to guard against such an accident, I prefer to employ
one or more non-return valves and also to pass the combustible mixture through
a chamber or tube which may be packed with refractory or other suitable
material such as iron wires, wire gauze or small pieces of iron or copper. Or
I may provide a fusible plug so arranged that in the event of the device employed
for preventing the lighting back becoming over-heated, the said plug will melt
and give relief to the combustible gases. Or the said chamber or tube may
contain some material which will be decomposed in case the flame should light
back and enter the chamber, the decomposition giving rise to products which
would either heat the chamber sufficiently to melt the aforesaid fusible plug or
extinguish the flame. For this purpose I can employ some combustible
material which on burning will generate the necessary heat to melt the fusible
plug or I can employ a bi-carbonate such as bi-carbonate of soda or of potass
or mixtures of these with or without the addition of other appropriate material
or mixture.
;

page_text: In order that my said invention may be clearly understood and readily
carried into effect I will proceed to describe the same more fully with reference
to the accompanying drawings, in which :-
Figure 1 is a sectional elevation of a motor-vehicle constructed in accordance
with my invention and in the form of a velocipede.
Figure 2 is a plan of the said vehicle with certain parts removed.
Figure 3 is a longitudinal section, drawn to a larger scale, shewing the working
cylinder and the air compressor.
Figure 4 is a vertical section, also drawn to a larger scale, showing the outer
end of the working cylinder, the valve gear, and the device for preventing
"lighting back" of the explosive mixture.
Figure 5 is a vertical section, also drawn to a larger scale, shewing the admission
valves for regulating the working charges passing to the motor.
A is the main member or back-bone of the framing, formed of a cylindrical
container or reservoir divided into compartments A' A2 A3 A4 by parti-
tions a a² a3. The compartment A¹ is open at the front and serves to contain
the vehicle lamp. The compartment A² serves as the compressed air container
and the compartment A³ serves as the container for the oil or other combustible
fluid. The compartment A serves to contain the electrical apparatus required
for supplying the electric current for working the igniter.
B is the front steering wheel carried by a fork B₁ mounted in the head B2
which extends through and is secured in the front part of the aforesaid cylin-
drical container A. The said fork and head are of the well known construction
common to ordinary velocipedes.
CC are the two rear driving wheels which are mounted in close proximity to
each other on the crank-shaft D with the crank D' located between them. The
said shaft D also carries a bevel wheel d that gears with a bevel wheel d¹
carried by the spindle which at its opposite end is provided with another
bevel wheel gearing with a bevel wheel d keyed to a shaft E. Mounted on
a spindle F adjacent to the said shaft E are two levers F 12 provided with
tails that lie in the path of cams E E Figure 4, mounted on the said shaft E.
The opposite ends of these levers respectively engage with the stems of the inlet
and exhaust valves G and H and during the revolution of the said shaft E and
its cam these levers are caused to oscillate and so operate the said valves in a
well understood manner.
The
I is the working cylinder and I the air compressor, these parts being con-
nected together co-axially (ie. with their axes in alignment) and with an inter-
mediate hollow or tubular portion I between them, as represented in Figure 3.
The working cylinder is of greater diameter than the air compressor.
pistons II are both mounted on the same piston rod I, and are made hollow
as shewn in Figure 3. The intermediate hollow or tubular portion I*, which
is detachable, is formed with longitudinal slots I through which project the ends
of a cross-pin 16 carried by the said piston rod. To the ends of the said cross-
pin are joined the members I of the forked connecting rod Is which is coupled
to the pin of the aforesaid crank D'. The end cover I of the said cylinder and
the end cover I10 of the said air compressor are provided with lugs I through
which extend tie rods or tubes 12 having collars I thereon contiguous to the
lugs on the end cover of the air compressor. The ends of said tie rods adjacent
to the end cover are furnished with nuts I by screwing up which, the
parts I I* I can be tightly secured together. I is a cross-head carrying the
bearings of the crank-shaft 1. It is connected with the cylindrical casing A
by a bracket A5, and has lugs [16 through which the prolonged ends of the said
tie-rods I extend. The latter are firmly connected to said cross-head by
sleeves 17 and nuts I¹8 A is another bracket connected with the cylindrical
casing A and supporting the motor at its forward end by the tie-rods I extending
through lugs on the said bracket.
The aforesaid cylinder cover I' is formed wtih a chamber I provided with the

page_text: inlet valve G and the aforesaid exhaust valve H. The casing surrounding the
valve G is connected to a pipe g that communicates at its upper end with a
chamber which is common to the two admission valves (see Figure 5).
These valves are provided with rotary plugs J³ J each of which can be indepen-
dently operated by the rider by means of handles J J. The valve J¹ com-
municates with the interior of the oil compartment A³. The other valve J2
communicates with a pipe K which extends through the said compartment A³,
without however communicating therewith, its forward end opening into the
compressed air compartment A2 and its rear end being connected with the air
compressor. Another pipe K (see Figure 1) cxtends trom the said compressed
air compartment into the aforesaid oil compartment A, the rearward end of
said pipe terminating at a point well below the level of the oil and being
provided with perforations at . When the motor is working the air compressor
forces air through the aforesaid pipe K into the compartment A2; the air being
compressed therein, passes along the pipe K and through the perforations in
the end thereof, into the body of oil contained in the compartment A3 and
by bubbling through the said oil reaches the space above the level of the oil,
in a gasified condition, that is to say strongly impregnated with the vapour of
the oil. By turning the valve into the position represented in Figure 5,
the gasified air can be allowed to pass along the pipe g into the chamber surround-
ing the inlet valve G, ready to enter the chamber 19, when the said valve is
opened by its lever F. On entering the said chamber I¹ the gasified air is
ignited and by its combustion and expansion actuates the piston I².
As already stated the air in its passage through the oil, becomes charged with
the oil vapour to a greater extent than is necessary to make it combustible,
therefore it is necessary to admit with the gasified air a certain proportion of
non-gasified air prior to the admission of the charge to the working cylinder.
By adjusting the position of the aforesaid valve J2 the desired quantity of the
non-gasified air can be allowed to pass from the compressed air compartment A²,
through the pipe K into the chamber between the two valves J1 J2, where it
can mingle with the combustible charge being supplied to the inlet valve through
the pipe g.
The aforesaid valves J and J not only regulate the proportions of
the gasified and non-gasified air admitted to the working cylinder and the volume
thereof, but also serve to start and stop the vehicle. In starting the vehicle
(assuming that the pressure of the compressed air in the compartment A2 is
sufficiently high) said vehicle is if necessary shifted to bring the crank I away
from its dead centre and then, after the rider has mounted the seat A7, he can,
by merely opening the valves JJ allow the gasified and compressed air to
enter the working cylinder and by its pressure alone start the vehicle.
The air compartment is provided with a non-return valve a, to which
I can connect an ordinary inflator pump and supply compressed air to said
reservoir in a similar manner to that now adopted for inflating the pneumatic
tyres of velocipedes. 1 thus obtain by hand an initial pressure of air in the said
compartment. a is a relief valve for permitting the compressed air in the
compartment A2 to escape when it reaches a pressure beyond that which is
required for the motor. When the vehicle is travelling down hill and it is
required to retard its speed the valves J1 J2 are both closed so that the motor
will then merely operate to compress air in the compartment A2; considerable
resistance will be thus offered to the travel of the vehicle and will act as a
brake.
At a suitable position on the pipe g I arrange a chamber g¹ (Figure 4) provided
with gauze or similar partitions 2 having between them particles of iron or
other suitable material for acting to prevent the lighting back of the gasified
air. The lower end of this chamber g is furnished with a non-return valve g
which may be of any ordinary construction. is the fusible plug which in the
event of the gasified air in the lower part of the pipe g becoming ignited, will

page_text: be melted at a temperature of about 300° F. and permit the flame to escape
through the aperture of said plug, thus affording an additional security against
the "lighting back" of the gasified air. When the aforesaid combustible
material or the fire-extinguishing material is employed it is preferably placed
in this chamber gl.
Within the chamber II provide a coil 20 (Figure 4) of copper ribbon or
other suitable material, adjacent to the inlet to the working cylinder, which coil
by becoming heated during the working of the motor acts as a regenerator for
raising the temperature of the gasified air as it passes on its way to the cylinder.
The said chamber I also contains an igniter which in the example illustrated
is an electric igniter worked from an induction coil (Figure 1) located in the
compartment A of the cylindrical container A. are battery cells which are
likewise arranged in the compartment A in circuit with the induction coil.
is a contact breaker situated in the electric circuit of the igniter and the
induction coil, at a point in proximity to a tappet on the crank shaft D so that
as said shaft rotates, the said contact breaker will alternately open and close the
circuit for causing the sparking at the igniter as is well understood. > is a switch
situated within easy reach of the rider for enabling him to throw the induction
coil into and out of action as may be required. For instance when the motor
has been running long enough for the interior of the working cylinder to be
heated to a temperature sufficiently high to ignite the charges admitted to the
cylinder, the induction coil can be switched out of circuit.
I prefer that the working cylinder should be partly made of or lined with
refractory material as set forth in the Specification of my prior Patent No. 9526
of 1896 such material being composed of porcelain or a mixture of clay, silica
and plumbago in about the proportions employed for making crucibles, which
mixture is very hard and withstands a high temperature. The head of the
piston 12 and the face of the cylinder cover 1º, I also prefer to provide with a
similar refractory substance. I am thus enabled to maintain a high temperature
inside the cylinder and prevent or mitigate radiation of heat therefrom. By
maintaining this high temperature in the cylinder I can use a very much weaker
mixture of oil vapour and air than is necessary where the cylinder is kept cool
by a water jacket.
L L' are the valves of the air compressor for respectively admitting air to the
said compressor and permitting it to pass to the pipe K during the working
of the piston of the said air compressor. These valves are of ordinary and well-
known construction and need no further description herein.
A8 is a cover for the end of the aforesaid compartment A' such cover being
made easily detachable so as to permit ready access to the interior of the said
compartment for replenishing the battery cells 2 or for other purposes.
Having now particularly described and ascertained the nature of ny said
invention and in what manner the same is to be performed, I'declare that what
I claim is:
1. A motor-driven velocipede or other light vehicle in which the two driving
wheels are mounted in close proximity to each other on a crank shaft that is
driven directly from the working cylinder substantially as and for the purpose
described.
2. The working cylinder and the air compressor of unequal diameters arranged
co-axially and having both pistons carried on a single piston rod which is
coupled to the crank by a forked or bifurcated connecting rol substantially as
and for the purpose specified.
3. The backbone or main frame of the vehicle constructed to serve as a
reservoir for containing the combustible fluid and the compressed air substantially
as described.
4. The combination with the aforesaid reservoir of a pair of admission valves,
one communicating with the combustible fluid compartment and the other with

page_text: the compressed air compartment of said reservoir substantially as and for the
purpose described.
5. The combination with the aforesaid compressed air compartment of a non-
return valve adapted to be connected with a hand air pump substantially as and
for the purpose specified.
6. A chamber located between the combustible fluid compartment and the
inlet valve of the engine, said chamber being packed with particles of refractory
or other suitable material and furnished with a non-return valve and with or
without a fusible plug substantially as and for the purpose specified.
7. The use with the aforesaid chamber and its fusible plug of a combustible
substance substantially as and for the purpose described.
8. The use between the combustible fluid compartment and the inlet valve of
the engine of a chemical substance which will decompose and generate fire
extinguishing products substantially as and for the purpose specified.
9. The lining or facing of the parts hereinbefore specified, with a mixture of
clay, silica and plumbago substantially as and for the purpose specified.
10. A motor velocipede having its parts, constructed, arranged and adapted
to operate substantially as described with reference to the accompanying drawings
for the purpose specified.
Doted this 28th day of February 1900.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.
Agents for the Applicant.