Improved Means for the Automatic Inflation of Pneumatic Tyres for Velocipedes and other Vehicles.
Year: 1898

page_text: Date of Application, 19th Jan., 1898
Complete Specification Left, 16th June, 1898-Accepted, 27th Aug., 1898
PROVISIONAL SIMCITICATION.
Improved Means for the Automatic Inflation of Pneumatic Tyres for
Velocipedes and other Vehicles.
We, JOSEPH KERSTING, Engineer, and Max HERZ, of the Firm of S. Herz,
both of 1, Dorotheenstrasse, Berlin, in the German Empire, do hereby declare the
nature of this invention to be as follows:-.
In cycling, it often happens that the tyres become slack during riding, thus
causing much inconvenience. This is more. especially the case when the air-
tube is punctured at any part.
Many attempts have already been made to obviate these disadvantages, by
combining the tyre with an arrangement whereby air is automatically compressed
into the air-tube during riding. The arrangements of this kind, which have
become known heretofore, cannot be brought to any practical success, since
they possess various faults which interfere with their action.
In these arrangements, one or more pump-cells or chambers are built into the
air-tube and are either unsupported, or are supported or re-inforced by a full or
solid piece of india-rubber. In the first case the incipient inflation of the air-
tube prevents the complete pressing-together of the pump-cell or chamber, and
the pressure of the air, contained in the air-tube and surrounding the pump-cell,
on the walls thereof prevents the re-expansion of the said cell or chamber and
consequently also the drawing-in of fresh quantities of air. In the second case,
the action of the pump is likewise considerably interfered with by the pressing-in
of its walls on increasing pressure, since the supporting or re-inforcing piece of
solid india-rubber displaces the centre of gravity of the wheel from the axis
thereof and, as long as the pump is in operation, causes an unbearable jarring
or series of shocks, whereby the spokes of the wheel are loosened. Moreover,
the inflation of the quite flat or slack tyre by means of this arrangement is
practically almost impossible by reason of the small delivery of the pump and
the violent shocks.
In order to obviate these disadvantages, according to the present invention,
the pump-cell or chamber is arranged outside the air-tube and it is supported,
in order to obtain complete pressing-together thereof, on a contracted part of
the air-tube, to which, at this particular place, the somewhat-greater resistance,
necessary for this purpose, is imparted.
At the place in question, by arranging transverse walls or partitions in the
interior of the air-tube a second pump-cell or chamber can be provided, which
acts in conjunction with that first mentioned, whereby, when commencing to
inflate a completely flat or slack tyre, the amount of air delivered is considerably
increased.
In carrying our said invention into practice, the air-tube, arranged in
the interior of the protective cover or sheath, is .contracted and its walls are
somewhat stouter along a suitable part of its length so that it there possesses
greater elasticity than at the remaining part of the tube. Under the action of

page_text: the circumferential tension of the air-tube, the contracted part of the tube lies
on the inner side of the protective cover or sheath, so that there is a free space
on the outer side of the wheel within the cover or sheath. In this space is
arranged the pump-cell or chamber which can be made of vulcanised india-
rubber, india-rubber with insertion, or other suitable material. The walls of
this cell or chamber can either be secured to the air-tube and cover or sheath,
so that they are continuously extended again by the elasticity of these parts
after pressing together, or their walls must themselves have sufficient elasticity.
in which case they need not be secured to the cover or sheath.
The pump-cell or chamber is provided with an inlet-valve and a delivery-valve
and to the former the atmospheric air is supplied in any suitable manner, for
example, through a tube passing transversely through the air-tube and opening
at the rim or felloe, whilst the air passes into the interior of the air-tube through
the latter (ie. the delivery-valve).
If, in the rotation of the wheel, the part of the protective cover or sheath
which contains the contracted part of the air-tube and the pump-cell or chamber,
rests on the ground, this part is pressed together under the weight of the rider.
In this manner the cell is pressed flat between the cover and the thickened
walls of the contracted part of the air-tube, and the air contained in this cell
escapes through the delivery valve into the air-tube.
In this, the contracted part of the air-tube presents an effective support for
the pump-cell or chamber. The resistance necessary for this purpose is imparted
to this part of the air-tube partly by the internal pressure and partly by the
elasticity of the material. Since the air, which the cell contains, is forced
through the delivery-valve into the interior of the air-tube, when the pressure
thereof is only a little higher than that of the air already contained in the air-
tube, the pumping action of the cell or chamber is entirely independent of the
pressure which exists in the interior of the air-tube. The constant elasticity
of the material of the contracted part of the air-tube in this arrangement, will
consequently always offer a certain excess of resisting power, so that the resist-
ance of the delivery valve will be overcome and the pump-cell or chamber emptied
as long as the tyre is sufficiently pressed-together for this purpose.
As soon as the part of the tyre containing the air-pump has left the ground,
the pump-cell again extends itself by virtue of its own elasticity or, if its wall is
made thin and is secured to the protective cover or sheath, by the effect of the
elasticity of the latter and it draws in air through the inlet-valve, which air
in the next operation of the pump, is forced into the air-tube.
As soon as the pressure in the air-tube has risen to such a degree that the
pressing-together of the tyre is less than corresponds to the contraction in the
air-tube, complete pressing-together of the pump-cell no longer takes place.
•
After each pressing-together some air under pressure consequently remains
in the cell, which, before a fresh quantity of air can be again drawn in, must
first expand to the atmospheric pressure. On further increase of the pressure,
and the consequent decrease in the pressing-together, the latter is no longer suffi-
cient to bring the air to a higher pressure than that in the air-tube, so that the
delivery-valve.no longer opens and the delivery or pumping action of the pump
ceases. The pump cell remains thus in a charged or distended condition filled
with a certain quantity of air at the pressure of the air-tube, which, on cessation
of the pressure, always re-expands to the atmospheric pressure and in this con-
dition entirely fills the cell, so that further drawing-in does not occur.
In order to obtain a rapid action of the pump, when commencing to ride
with a quite deflated air-tube, it is advantageous to form a second pump-cell in
combination with the pump-cell above mentioned, this being effected by arranging
transverse partitions in the contracted part of the air-tube.
For this purpose one of these transverse partitions is provided with a valve.
And on the other side of the cell or chamber formed by these partitions is
arranged a third partition so as to form a small auxiliary chamber which is in

page_text: communication with the external air through an aperture in the protective cover
or sheath and in the rim or felloe and enables this air to have access to the
inlet-valve of the cell or chamber on the exterior of the air-tube.
Obviously this small auxiliary chamber may be omitted, and the said inlet
valve brought into communication with the external air through a tube as in
the arrangement first mentioned.
The air passes thus into the pump-cell external to the air-tube, and thence
into the pump-cell internal to the air-tube, whence it passes into the air-space
of the tyre.
It is also possible, to arrange the pump-cell on the inner side of the air-tube,
between this and the part of the cover held by the rim or felloe. This will even
offer the advantage that the supply of air to the inlet-valve will be rendered
considerably simpler. It is however somewhat difficult to arrange the pump-cell
or chamber so as to operate efficiently in this position, since the circumferential
tension of the air-tube will always have the tendency to press the pump-cell
together against the rim-side of the cover or sheath so that the drawing-in of
the air is also interfered with by the employment of stouter and more rigid walls
for the pump-cell or chamber. The arrangement first mentioned is thus prefer-
able.
Our improved air-pump, as we have proved by experiment, pumps-in the neces-
sary amount of air very rapidly, renders a hand-pump unnecessary and obviates
the detrimental effect of punctures or other injuries of the air-tube
by continuously replacing the air which has escaped therefrom.
D. YOUNG & Co.,
11 and 12, Southampton Buildings, London, W.C.,
Agents for the Applicants.
Improved Means for the Automatic Inflation of Pneumatic Tyres for
Velocipedes and other Vehicles.
We, JOSEPH KERSTING, Engineer, and MAX HERZ, of the Firm of S. Herz,
both of 1. Dorotheenstrasse, Berlin, in the German Empire, 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:-
In cycling, it often happens that the tyres become slack during riding, thus
causing much inconvenience. This is more especially the case when the air-
tube is punctured at any part.
Many attempts have already been made to obviate these disadvantages, by
combining the tyre with an arrangement whereby air is automatically compressed
into the air-tube during riding. The arrangements of this kind, which have
become known heretofore, cannot be brought to any practical success, since
they possess various faults which interfere with their action.
In these arrangements, one or more pump-cells or chambers are built into the
air-tube and are either unsupported, or are supported or re-inforced by a solid
piece of india-rubber. In the first case the incipient inflation of the air-tube
prevents the complete pressing together of the walls of the pump-cell or chamber,
and the pressure of the air contained in the air-tube and surrounding the pump-
cell, on the walls thereof, prevents the re-expansion of the said cell or chamber
and consequently also the drawing-in of fresh quantities of air. In the second

page_text: case, the action of the pump is likewise considerably interfered with. by the
pressing-in of its walls on increasing pressure, since the supporting or re-inforc-
ing piece of solid india-rubber displaces the centre of gravity of the wheel from
the axis thereof and, as long as the pump is in operation, causes an unbearable
jarring or series of shocks, whereby the spokes of the wheel are loosened.
Moreover, the inflation of the quite flat or slack tyre by means of this arrange-
ment is practically almost impossible by reason of the small delivery of the
pump and the violent shocks.
In order to obviate these disadvantages, according to the present invention,
the pump-cell or chamber is arranged outside the air-tube and is supported,
in order to obtain complete pressing-together of the walls thereof, on a contracted
part of the air-tube, to which, at this particular place, the somewhat-greater
resistance, necessary for this purpose, is imparted.
At the place in question, by arranging transverse walls or partitions in the
interior of the air-tube, a second pump-cell or chamber can be provided, which
acts in conjunction with that first mentioned, whereby, when commencing to
inflate a completely flat or slack tyre, the amount of air delivered is considerably
increased.
In the accompanying drawing,
Figure 1 shows our improved automatic pump in longitudinal section;
Figure 2 is transverse section in its extended condition, and
Figure 3 in its compressed condition.
Figure 4 shows the modification of our improved pump in which a second
cell or chamber is formed in the interior of the air-tube by arranging transverse
walls therein.
The air-tube arranged in the interior of the protective cover or sheath, m,
is contracted at a and its walls are made somewhat stouter along a suitable part
of its length as at e and are made inexpansible by the insertion of fabric, thus
there is a greater elasticity at this place than at the remaining part of the tube.
Under the action of the circumferential tension of the air-tube, the contracted
part thereof lies on the inner side of the protective cover or sheath so that there
is a free space left on the outer side of the wheel within the cover or sheath.
In this space is arranged the pump-cell or chamber p which can be made of
vulcanized india-rubber, india-rubber with insertion, or other suitable material.
The walls of this cell or chamber can either be secured to the air-tube and cover
or sheath, so that they are continually re-extended by the elasticity of these
parts after having been pressed-together, or their walls must themselves have
sufficient elasticity, in which case they need not be secured to the cover or
sheath m.
The pump-cell or chamber is provided with an inlet-valves and a delivery-
valve ; and to the former the atmospheric air is supplied in any suitable
manner, for example, through a tube passing transversely through the air-
tube and opening at the rim or felloe f, whilst the air passes into the interior
of the air-tube through the delivery-valve d.
If, in the rotation of the wheel, the part of the protective cover or sheath
which contains the contracted part of the air-tube and the pump-cell or
chamber prests on the ground, this part is compressed under the weight of the
rider.
.F
In this manner the cell p is pressed flat between the cover and the thickened
walls e of the contracted part of the air-tube, and the air contained in this cell
escapes through the delivery-valve d into the air-tube.
The contracted part of the air-tube meanwhile presents an effective support
for the pump-cell or chamber. The resistance necessary for this purpose is im-
parted to this part of the air-tube partly by the internal pressure and partly by
the elasticity of the material. The air, which the cell contains is forced through
the delivery-valve d into the interior of the air-tube, when the pressure thereof
´ is only a little higher than that of the air already contained in the air-tube 1.

page_text: The constant elasticity of the material of the contracted part of the air-tube
in this arrangement, will consequently always provide a certain excess of resisting
power, so that the resistance of the delivery-valve d will be overcome and the
pump-cell or chamber emptied, as long as the tyre is sufficiently compressed
for this purpose.
As soon as the part of the tyre containing the air-pump has left the ground,
the pump-cell ? again extends itself by virtue of its own elasticity, or, if its
wall is made thin and is secured to the protective cover or sheath m, by
the effect of the elasticity of the latter, and draws in air through the inlet-valve s,
which air, in the next operation of the pump, is forced into the air-tube l.
As soon as the pressure in the air-tube has risen to such a degree that the
compression of the tyre is less than corresponds to the contraction in the air-
tube, complete pressing-together of the walls of the pump-cell no longer takes
place.
After each compression, some air under pressure consequently remains in the
cell, which, before a fresh quantity of air can be again drawn in, must first
expand to the atmospheric pressure. On further increase of the pressure, and
consequent decrease in the compression, the latter is no longer sufficient to bring
the air to a higher pressure than that in the air-tube, so that the delivery-
valve d no longer opens and the delivery or pumping action of the pump ceases.
The pump-cell remains thus in a charged or distended condition filled with a
certain quantity of air at the pressure of the air-tube, which, on cessation of
the pressure, always re-expands to the atmospheric pressure and in this condition
entirely fills the cell, so that further drawing-in does not occur.
In order to obtain a rapid action of the pump, when commencing to ride
with a quite deflated air-tube, it is advantageous to form a second pump-cell q
in combination with the pump-cell 2 above mentioned, this being effected, by
arranging transverse partitions g and j in the contracted part of the air-tube 7
as shown in Figure 4.
For this purpose one of these transverse partitions ; is provided with a valve v.
And on the other side of the cell or chamber q formed by these partitions, is
arranged a third partition h so as to form a small auxiliary chamber which
is in comunication with the external air through apertures in the protective
cover or sheath and in the rim or felloe and enables this air to have access to
the inlet valve s of the cell or chamber p on the exterior of the air-tube.
Obviously this small auxiliary chamber may be omitted, and the valve s
brought into communication with the external air through a tube ras in the
arrangement shown in Figure 1.
The air thus passes into the pump-cell and thence into the pump-cell
whence it enters the air-space of the tyre.
It is also possible, to arrange the pump-cell p on the inner side of the air-tube,
between this and the part of the cover held by the rim or felloe. This arrange-
ment will even offer the advantage that the supply of air to the inlet-valve s
will be rendered considerably simpler. It is however somewhat difficult to arrange
the pump-cell or chamber so as to operate efficiently in this position, since the
circumferential tension of the air-tube will always have the tendency to press
the pump-cell together against the rim-side of the cover or sheath m, so that the
drawing-in of the air will also be interfered with by the employment of stouter
and more rigid walls for the pump-cell or chamber. The arrangement first
mentioned is thus preferable.
Our improved air-pump can also be employed in combination with a simple
air-tight velocipede-tyre made without an inner air-tube. In this case the outer
pump-cell can be simply fastened to the exterior of the tyre so that the pneu-
matic tyre is formed similarly to the inner air-tube in the arrangement shown in
Figures 1 and 2. In this case a second pump-cell can also be advantageously
employed within the pneumatic tyre similar to that shown in Figure 4, only
with the difference already mentioned that the running sheath or outer cover m

page_text: is dispensed with, whilst the walls of the air-tubes are made of such strength
that they can resist the internal air pressure and the stresses produced during
riding.
Finally the two corresponding air-cells can be mounted in the interior of the
air chamber, when employing a simple pneumatic tyre. For this purpose in
the arrangement shown in Figure 4, only the continuations of the inner air-tube
at the two ends of the pump-cell q are dispensed with and the two cells P and q
must be cemented into the air-tube at the place shown in this Figure 4.
Our improved air-pump, as we have proved by experiment, pumps-in the
necessary amount of air very rapidly, renders a hand-pump unnecessary and
obviates the detrimental effect of punctures or other injuries of the air-tube by
continuously replacing the air which has escaped therefrom.
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 combination with a pneumatic tyre, an automatic air-pump consisting of
a pump-cell or chamber which is provided with suction and delivery-valves and
is arranged on the tread side of an air-tube which is strengthened and made
inexpansible at this place in such a manner that it supports the inner wall of the
pump-cell during the compression of the corresponding part of the tyre.
2. In a pneumatic wheel-tyre, the combination of an inner air-tube and a
pump-cell provided with suction and delivery-valves arranged outside the same,
and a second pump-cell separated by transverse walls from and arranged in the
interior of the air-tube at the strengthened and inexpansible part of the said
air-tube which supports the first cell, this second cell being in communication,
through a valve opening towards the interior of the air-tube, with the said air-tube,
and through the delivery valve of the first mentioned pump-cell with the latter.
3. In combination with a single-tube pneumatic tyre, a pump-cell secured
against a contracted part of the said tyre at the outside thereof and provided
with suction and delivery-valves, which cell is supported by the pneumatic tyre
during its compression.
4. In combination with a single-tube pneumatic tyre, an air-pump cemented
into the interior thereof and consisting of an inner and an outer cell, the inner
cell being separated off in a short air-tube in the form of a strengthened and
inexpansible pump-cell by transverse walls of this short air-tube, substantially as
described.
D. YOUNG & Co.,
11 and 12, Southampton Buildings, London, W.C.,
Agents for the Applicants.