Improvements in Valves for Pneumatic Tyres.
Year: 1897

page_text: Date of Application, 4th Aug., 1897
Complete Specification Left, 19th Oct., 1897-Accepted, 11th Dec., 1897
Improvements in Valves for Pneumatic Tyres.
I, JULIUS MOHS, of Brandenburg a/Havel, Kingdom of Prussia, Empire of
Germany, Manufacturer, do hereby declare the nature of this invention to be as
follows:-
This invention relates to improvements in the air-supply valves of pneumatic tyres
for cycles and other vehicles and particularly to the arrangement of the flexible tube
by means of which air passes into the tyre during pumping and which prevents its
escape, and to the elastic mounting of this flexible tube in its casing.
As is well known a longitudinal slit in a rubber tube forins a valve that will allow
air to pass out of the tube but will not allow it to enter therein. Such a lip-valve,
however, as practice has shown, is not suitable for cycles and other purposes in which
high pressure is used because such pressure causes the tube to be pressed flat
resulting in the springing open of the slit to a greater or less extent and consequently
the escape of the air. This drawback is obviated according to this invention by
making the rubber-tube so strong that the compression of the tube by means of
external pressure is no longer possible-i.e., the wall is as thick or thicker than the
width of the passage of the tube.
Experiments I have made however have shown that the mere strengthening of the
tube cannot completely remove the drawback of the gradual escape of the air and
that for the attainment of the purpose in view, at least three or even more of such
slits must be provided on an annular zone of the tube; because only one slit be
provided, the external air-pressure will, as indicated at B in Fig. 4 of the
accompanying drawings, cause the bending-in even to only a small extent of the tube
at the place in question and as a result of this an angularity of the slit-edges and
consequently a loosening of the slit, as the edges of the slit-surfaces are constantly
moving during the vibration of the cycle. The same is true as regards two slits.
The tube acts quite differently, however, when three, four or still more slits are
arranged on an annular zone. The whole tube then behaves like a stone arch the
joints of which can yield slightly that is to say the several parts of the rubber-tube
are obliged, as for example is indicated in Fig. 5, to move radially inwards when
strong external pressure takes place on the tube, as indicated by dotted lines,
without injuring the circular form of the tube at the zone at which the slits are
provided. The angularity of the edges indicated at B in Fig. 4 can consequently
not occur.
The above mentioned fact is taken advantage of in the valve represented in
Figs. 1 to 3 of the accompanying drawings.
Figs. 1 and 2 show the rubber tube in longitudinal section and horizontal section
respectively and to an enlarged scale.
The air enters through a pump-ajutage into the lower closed rubber tube aand widens
it at the zonal part at which the slits 61, b/², b³, b/4 are provided (Figs. 1 and 2);
during this operation the slits open so that the air can pass out of the tube in the
direction of the arrows 61, 62, 63, 64 (Fig. 2). If, however, the pressure within the
tube decreases, the slits, which, moreover, had opened only to quite a minimum
[Price]

page_text: extent, close again momentarily, whereas external pressure acting on the tube a in
the direction of the arrows marked a² in Fig. 2, compresses the tube like an arch,
because as in consequence of the comparatively great wall-thickness, the tube cannot
be pressed flat, it can at the zone having the slits, only assume a smaller diameter,
as indicated in Fig. 5, the several bands of the tube produced by the slits
consequently moving relatively to one another radially like the jaws of a tool-
holder.
Figs. 6 and 7 show tubes in which the wall is not plainly cylindrical but is
bellied thus increasing the strength of the pouch as regards compression, whilst an
easier and more precise opening and closing of the slits is simultaneously obtained.
As will be obvious, the rubber valve may be formed as a pouch, i.e., as shown
in Figs. 1 and 8, closing together at the bottom, or simply as a flexible tube, in
which case, as in Fig. 12, the lower open end is closed with a stopper S, and for
. securing the stopper the tube end is surrounded with a ring S.
The flexible tube or the pouch serving as a valve is secured in its closing device in
such a manner that it is elastically mounted. This elastic mounting is of importance
because it prevents the destruction of the flexible tube that has hitherto been
observed in the rubber-valves of cycles at the end at which it is acted upon by the
coupling formed as an "over-nut" for fastening it; moreover, the helical spring that
effects the elastic mounting and surrounds the flexible tube forms an intermediate
member between the flexible tube and the outer-tube inner wall, which prevents the
outer wall of the flexible tube from bearing against the inner wall of the outer tube;
this is specially important in the case of the above-characterized valves with 4
longitudinal slits, which are to allow the exit of the air-current uniformly and in
the case of which consequently band-like parts of the flexible tube, which are formed
by the slits, are to expand uniformly on the opening of the slits.
The fixing of the flexible tube in its closing-device is represented in vertical medial
section in Fig. 8.
The outer tube x is as usual provided with a lower flange and an external screw-
thread for fastening it to the pneumatic tyre and to the rim of the wheel.
At the top the outer tube is provided with an internal screw-thread for the
reception of the closing-part y, which has an external screw-thread corresponding to
the internal screw-thread in and a further external screw-thread for the attachment
of the air-pump and the closing-cap. Before screwing in the closing part y, the
rubber pouch a is provided with, a perforated ball at its upper end and then inserted
with the helical spring w surrounding the flexible tube. The helical spring bears at
the bottom against the bottom of the outer tube and at the top against the ball. If,
now, the closing-part y is screwed into the outer tube x, it forces back the flexible
tube and the spring, as the spring yields and a squeezing-off of the uppermost part
of the flexible tube can never take place during this screwing-in as the flexible tube
does not present an invulnerable resistance and can rotate under the action of the
screwing-in of y. The elastic mounting of the flexible tube does not injuriously
affect its position and mode of operation in any way, whilst the pressure exerted by
the helical spring w effects a tight-jointing of the flexible tube in relation to the
closing-party.
In addition, there may be placed on the upper end of the outer tube x a leather or
rubber washer v, which, by the screwing in of y, further tight-joints the closing-
device towards the exterior.
The spring w, which surrounds the flexible tube, does not prevent the flexible tube
from being expanded in any way in its slit-zone; but it prevents the outer wall of
the flexible tube from bearing against the inner wall of the outer tube. Under all
circumstances the spring w presents air-ways for the air passing out of the flexible
tube into the pneumatic tyre.
Instead of the perforated ball z there may be employed a perforated body z¹
(Fig. 9) which is lens-shaped in cross section, or a ring 1 (Fig. 10). The ring 211
may, as in Fig. 10, be inserted into the upper end of the flexible tube or pouch, or
it may be put on outside around the said end, in the case of which arrangement. it

page_text: is pushed on so far, as shown by Fig. 11, that the end of the flexible tube is drawn or
turned back.
Whether a ball, a lens-shaped body, or an internal or external ring is employed,
these parts form essentially the abutment for the upper end of the helical spring w
in order to produce pliability during the screwing-in of the closing-part y and the
joint-tightening of the flexible tube in relation to the screwed-in closing-party.
A modification of the externally placed-round ring 211 is represented in Fig. 12,
for the ring, as shown in detail in Figs. 13 and 14, is provided with prolongations 111,
which embrace the flexible tube a and can extend beyond the slit-zone of the flexible
tube.
In the case of the employment of this external ring 21 with its prolongations 2111
there can also be used a helical spring w surrounding this part. The prolongations,
which leave the slits of the flexible tube between them, form an abutment for the
flexible tube; in consequence of their elastic property, permit the opening of the
slits and the expansion of the bands which form the flexible tube in the slit zone;
but they also simultaneously perform the service of a protective wall for the flexible
tube in relation to such external pressure as will exercise an ununiform. compression
of the same.
I, JULIUS MOHS, of Brandenburg a/Havel, Kingdom of Prussia, Empire of
Germany, Manufacturer, 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 improvements in the air-supply valves of pneumatic tyres
for cycles and other vehicles and particularly to the arrangement of the flexible tube
by means of which air passes into the tyre during pumping and which prevents its
escupe, and to the elastic mounting of this flexible tube in its casing.
As is well known, a longitudinal slit in a rubber tube forms a valve that will allow
air to pass out of the tube but will not allow it to enter therein. Such a lip-valve,
however, as practice has shown, is not suitable for cycles and other purposes in which
high pressure is used because such pressure causes the tube to be pressed flat
resulting in the springing open of the slit to a greater or less extent and consequently
the escape of the air. This drawback is obviated according to this invention by
making the rubber-tube so strong that the compression of the tube by means of
external pressure is no longer possible-i.e., the wall is made as thick or thicker than
the width of the passage of the tube.
Experiments that I have made however, have shown that the mere strengthening
of the tube cannot completely remove the drawback of the gradual escape of the air
and that for the attainment of the purpose in view at least three or even more such slits
must be provided in an annular zone of the tube; because if only one slit be provided,
the external air-pressure will, as indicated at B in Fig. 4 of the drawings filed with my
provisional specification, cause the bending-in of the tube, even if to only a small
extent at the place in question and as a result of this an angularity or inclination to
each other of the normally contiguous surfaces of the slit and consequently a

page_text: loosening of the slit, as the edges of the slit-surfaces are constantly moving during
the vibration of the cycle. The same is true as regards two slits.
The tube acts quite differently, however, when three, four, or still more slits are
arranged in an annular zone. The whole tube then behaves like a stone arch the
joints of which can yield slightly-that is to say, the several parts of the rubber-tube
are obliged, as for example is indicated by dotted lines in Fig. 5, to move radially
inwards when strong external pressure takes place on the tube, without injuring the
circular form of the tube at the zone in which the slits are provided. The angularity
of the edges indicated at B in Fig. 4 can consequently not occur.
The above mentioned fact is taken advantage of in the valve represented in
Figs. 1 to 3 of the drawings herein before referred to.
Figs. 1 and 2 show the rubber tube in longitudinal section and horizontal section
respectively and to an enlarged scale.
The air enters through a pump-ajutage into the lower closed rubber tube a and
widens it at the zoual part in which the slits 61, 62, 63, 64 are provided (Figs. 1 & 2);
during this operation the slips open so that the air can pass out of the tube in the
direction of the arrows b¹, 62, 63, 64 (Fig. 2). If, however, the pressure within the
tube decreases, the slits, which, moreover, had opened only to quite a minimum
extent, close again momentarily, whereas external pressure acting on the tube a in
the direction of the arrows marked a² in Fig. 2, compresses the tube like an arch,
because, as in consequence of the comparatively great wall-thickness, the tube cannot
be pressed flat, it can, at the zone having the slits, only assume a smaller diameter,
as indicated in Fig. 5, the several bands of the tube produced by the slits consequently
moving relatively to one another radially like the jaws of a tool-holder.
Figs. 6 and 7 show tubes in which the wall is not plainly cylindrical but is bellied,
whereby the strength of the tube is increased as regards compression, whilst an easier
and more precise opening and closing of the slits is simultaneouly obtained.
As will be obvious, the rubber valve may be formed as a pouch, i.e., as shown in
Figs. 1 and 8, closing together at the bottom, or simply as a flexible tube, in which
case, as in the example shown in Fig. 12, the lower open end is closed with a stopper
of any suitable material such as metal, and for securing the stopper the tube-end may
be surrounded with a wire or a ring S.
The flexible tube or the pouch serving as a valve is secured in its casing in such a
manner that it is elastically mounted. This elastic mounting is of importance because
it prevents the destruction of the flexible tube that has hitherto been observed in the
rubber-valves of cycles at the end at which it is acted upon by the coupling formed as
an inwardly flanged nut for fastening it; moreover, the helical spring that effects the
elastic mounting and surrounds the flexible tube forms an intermediate member
between the flexible tube and internal surface of the outer-tube, which prevents the
external surface of the flexible tube from bearing against the internal surface of the
outer tube; this is specially important in the case of the herein before described valves
with four longitudinal slits, which are to allow the air-current to escape uniformly
and in the case of which consequently the band-like parts of the flexible tube formed
by the slits, are to expand uniformly on the opening of the slits.
The fixing of the flexible tube in its casing is represented in vertical medial section
in Fig. 8..
The outer tube x is, as usual, provided with a lower flange and an external screw-
thread for fastening it to the pneumatic tyre and to the rim of the wheel.
At the top, the outer tube is provided with an internal screw-thead for the
reception of the closing-part y, which has an external screw-thread corresponding to
the internal screw-thread in x and a further external screw-thread for the attachment
of the air-pump and the closing-cap. Before screwing-in the closing part y, the
rubber pouch a is provided with a perforated ball at its upper end and then inserted
with the helical spring w surrounding the flexible tube. The helical spring bears at
the bottom against the lower end of the outer tube and at the top against the ball.
If, now, the closing-party is screwed into the outer tube x, it forces back the flexible
tube and the spring, as the spring yields and the uppermost part of the flexible tube

page_text: can never be squeezed off during this screwing-in as the flexible tube does not present
an insuperable resistance and can rotate under the action of the screwing-in of y.
The elastic mounting of the flexible tube does not injuriously affect its position and
mode of operation in any way, whilst the pressure exerted by the helical spring w
effects a tight-jointing of the flexible tube in relation to the closing-part y.
In addition, there may be placed on the upper end of the outer tube x a leather or
rubber washer v, which, by the screwing-in of y, further tight-joints the casing as
regards the exterior.
The spring w, which surrounds the flexible tube, does not prevent the flexible tube
from being expanded in any way in its slit-zone; but it prevents the outer wall of the
flexible tube from bearing against the inner wall, of the outer tube. The spring w
always presents air-ways for the air passing out of the flexible tube into the pneumatic
tyre.
Instead of the perforated ball z there may be employed a perforated body 21 (Fig. 9)
which is lens-shaped in longitudinal section, or a ring (Fig. 10). The ring z¹
may, as in Fig. 10, be inserted into the upper end of the flexible tube or pouch, or it
may be put on outside around the said end, in the latter case being pushed on so far,
as shown in Fig. 11, that the end of the flexible tube can be drawn or turned back.
Whether a ball, a lens-shaped body, or an internal or external ring is employed,
these parts form essentially the abutment for the upper end of the helical spring w
for producing pliability during the screwing-in of the closing-part y and the joint-
tightening of the flexible tube in relation to the screwed-in closing part y.
A modification of the external ring 11 is represented in Fig. 12, for the ring, as
shown in detail in Figs. 13 and 14, is provided with prolongations z111, which embrace
the flexible tube and may, as shown, extend beyond the zone containing its slits.
In the case of the employment of this external ring 21 with its prolongations 2111,
there can also be used a helical spring w surrounding this part. The prolongations,
which have the slits of the flexible tube between them, form an abutment for the
flexible tube; in consequence of their elasticity, when internal pressure is produced by
pumping air in they permit the opening of the slits and the expansion of the bands
which form the flexible tube in the slit-zone; but they also simultaneously perform
the service of a protective wall for the flexible tube in relation to such external
pressure as would produce an ununiform compression of the same.
In Figs. 8, 9, 10, and 12 the spherical, lenticular, or annular body (z, 2', 2) that
forms a resistance for the upper end of the helical spring w, is shown as a separate
part. It may, however, as is obvious, be rigidly attached to the closing part y, as in
the case of the body z shown in the accompanying Fig. 15, so that the closing part y
with the body z and the tube or pouch may be together inserted or screwed into the
outer tube x against the pressure of the spring w.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what I
claim is
1. A valve consisting of a slit flexible tube or pouch having such a strength of wall
that it cannot be pressed flat by the external pressure to which it is subjected and
having in it three or more slits 61 62 arranged in a zone so that the bands produced in
the flexible tube by, and located between, the said slits are wedge-like in cross section
and can move radially and independently without its being possible for the flexible
tube or pouch to be pressed flat or for the normally contiguous surfaces of a slit to be
inclined to each other.
2. Elastically mounting a valve of the kind mentioned in the preceding claim by
means of a helical spring w that surrounds the flexible valve-tube or valve-pouch a,
in a casing comprising an outer tube x and a closing-part y screwed into the latter.
3. Furnishing a valve of the kind mentioned in claim 1 with a surrounding ring z",
whose elastic prolongation 2111 serve as protective clothing for the valve-wall.
4. A valve of the kind referred to in claim 1, made of an elastic tube having one of
its ends closed by means of a stopper of metal or other suitable material, whether or-

page_text: not the said stopper be held in position by a wire or a ring S surrounding the tube,
substantially as herein before described with reference to and shown in Fig. 12 of the
drawings.
Dated this 19th day of October 1897.
F. WISE HOWORTH
46 Lincolns Inn Fields London W.C., Agent for the Applicant.