An Improved Back Pressure Valve for Pneumatic Tyres, Air Cushions, and the like.
Year: 1897

page_text: An Improved Back Pressure Valve for Pneumatic Tyres, Air
Cushions, and the like.
A communication by the Firm of RATZINGER and WEIDENKAFF, of 2, Trager-
strasse, Munich, in the Empire of Germany, Manufacturers.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of the Agency for Foreign
Patent Solicitors, 6, Lord Street, Liverpool, and 6, Bank Street, Manchester, both
in the County of Lancaster, 118, New Street, Birmingham, in the County of War-
wick, and 322, High Holborn, in the County of Middlesex, Civil Engineer, do
hereby declare the nature of this invention to be as follows:-
This invention has for its object a back pressure valve for pneumatic tyres, air
cushions and the like which affords a convenient and easy inflating and yet pre-
vents any escape of the air when once pumped in.
The improved valve consists essentially of a casing perforated longitudinally
and fastened to the hollow rubber tyre or air tube and wheel rim in the usual
manner by means of a flange, washer disc, and nuts.
The diameter of the passage in the casing is not of an even width throughout
but tapers towards the top where it is rounded to a larger diameter so that it
assumes a nozzle-like form. In the upper wider bore a screw thread is cut in order
to receive therein a screwed holder provided with spring arms, said holder being
divided into two parts longitudinally by means of a milled collar. The thread of
the holder having a left hand pitch above the collar and a right hand one below.
The upper part of this holder has an exterior thread up to the commencement
of the spring arms, on which thread is screwed a cap having an attachment
nozzle for the air pump or the like.
A metal valve cone is loosely suspended in the bore or passage of the valve
casing, the taper of which cone is however somewhat steeper than that of the
bore of the said passage so that on the closing of the valve, the whole surface of
the valve cone cannot bear on the wall of the passage but only on a quite narrow
surface or line. By this means surface washering is avoided which, as is well
known, is never to be obtained thoroughly tight on account of the unevenness, and
a thoroughly tight joint is obtained on a narrow circle of the passage.
The valve cone has a shoulder or collar at the top which rests on the spring
arms which are bent over at their upper ends to hold the valve at its narrow part
or neck but leaving it free to move upwards.
As special advantages of this improved valve there must be mentioned above all
the purely metallic joint without the use of any other washer material and the
use of a very narrow joint line instead of surface joints which are difficult to
render tight.

page_text: The mode of working is as follows:-
Before commencing to pump in air, the screwed holder with the nozzle and the
valve cone are screwed down until the milled collar of the holder rests on the
upper edge of the valve casing and the valve cone hangs free in the bore or passage
so that there is room for play between it and the inner wall of the nozzle like
bored out valve casing.
The air pump is then set in action and the air pumped in takes its course
through the annular space between the valve cone and the inner wall of the valve
casing directly into the pneumatic tyre. If only a slight super pressure exists
in the interior of the tyre the valve cone is raised automatically and it is then
sufficient in order to obtain an entirely certain closing of the valve, to screw the
milled collar a few turns upward, thus liſting the screwed holder, the cone sup-
ported on the spring arms of the same, and the attachment nozzle, by which means
the valve cone is drawn firmly against the inner wall of the valve casing and
there forms a tight joint over a very narrow surface.
In order if necessary to allow air to escape from a too strongly inflated tyre,
it is sufficient to again screw downwards a little the screwed holder in order that
the air may escape between the valve cone and the inner wall of the valve casing.
Dated this 14th day of June 1897.
An Improved Back Pressure Valve for Pneumatic Tyres, Air
Cushions, and the like.
A communication by the Firm of RATZINGER and WEIDENKAFF, of 2, Trager-
strasse, Munich, in the Empire of Germany, Manufacturers.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of the Agency for Foreign
Patent Solicitors, 6, Lord Street, Liverpool, and 6, Bank Street, Manchester, both
in the County of Lancaster, 118, New Street, Birmingham, in the County of War-
wick, and 322, High Holborn, in the County of Middlesex, Civil 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 has for its object a back pressure valve for pneumatic tyres, air
cushions and the like which affords a convenient and easy inflating and yet pre-
vents any escape of the air when once pumped in.
In the accompanying drawings:-
Figure 1 is a longitudinal section of the valve open,
Figure 2 a similar view with the valve closed, and
Figure 3 a plan view of the resilient screwed holder carrying the valve plug.
The improved valve consists essentially of a casing a perforated longitudinally
and fastened to the hollow rubber tyre or air tube f and wheel rim g in the usual
manner by means of a flange b, washer disc c, and nuts d and e.
The diameter of the passage in the casing a is not of an even width throughout
but tapers towards the top where it is rounded to a larger diameter so that it
assumes a nozzle-like form. In the upper wider bore a screw thread is cut in
order to receive therein a screwed holder k provided with spring arms i, said holder
being divided into two parts longitudinally by means of a milled collar; the
thread of the holder having a left hand pitch above the collar and a right hand

page_text: one below. The upper part of this holder has an exterior thread up to the com-
mencement of the spring arms i, on which thread is screwed a cap n having an
attachment nozzle m for the air pump or the like, a left hand thread is provided
in order that when the screwed holder is screwed up, the cap n cannot become
loose.
A metal valve cone o is loosely suspended in the bore or passage h of the valve
casing, the taper of which cone is however somewhat steeper than that of the
bore of the said passage h so that on the closing of the valve the whole surface of
the valve cone o cannot bear on the wall of the passage h but only on a quite
narrow surface or line. By this means surface washering is avoided which, as is
well known, is never to be obtained thoroughly tight on account of the uneven-
ness, and a thoroughly tight joint is obtained on a narrow circle of the passage h.
The valve cone o has a shoulder or collar p at the top which rests on the spring
arms which are bent over at their upper ends and thus form the point of sus-
pension of the valve cone o. This affords a convenient means of releasing the
valve cone by forcing the spring arms apart when taking the valve to pieces.
Beneath the shoulder p there is a short neck against which the bent in ends of
the spring arms i do not press so that they do not prevent a slight lift of the
valve during the back pressure action.
9
As special advantages of this improved valve there must be mentioned above
all the purely metallic joint without the use of any other washer material and the
use of a very narrow joint line instead of surface joints which are difficult to
render tight.
The mode of working is as follows:-
Before commencing to pump in air, the screwed holder with the nozzle m
and the valve cone o are screwed down until the milled collar 7 of the holder rests
on the upper edge of the valve casing a and the valve cone o hangs free in the
bore or passage h (Figure 1) so that there is room for play between it and the
inner wall of the nozzle-like bored out valve casing a.
The air pump is then set in action and the air pumped in takes its course
through the annular space between the valve cone and the inner wall of the valve
casing directly into the pneumatic tyre. If only a slight super pressure exists
in the interior of the tyre the valve cone o is raised automatically and it is then
sufficient in order to obtain an entirely certain closing of the valve, to screw the
milled collar a few turns upward, thus lifting the screwed holder k, the cone o
supported on the spring arms i of the same, and the attachment nozzle m, (see
Figure 2), by which means the valve cone o is drawn firmly against the inner
wall of the valve casing a and there forms a tight joint over a very narrow sur-
face.
In order if necessary to allow air to escape from a too strongly inflated tyre,
it is sufficient to again screw downwards a little the screwed holder k in order
that the air may escape between the valve cone o and the inner wall of the valve
casing a.
Having now particularly described and ascertained the nature of the said in-
vention and in what manner the same is to be performed, as communicated to me
by my foreign correspondents, I declare that what I claim is :-
1. A back pressure valve for pneumatic tyres, air cushions and the like,
characterised by a valve cone (o) of metal or material resembling metal being
suspended on a holder (k) adapted to be screwed up and down in a casing (a)
shaped like a nozzle whereby the valve cone (o) may be caused to descend so far
as to leave an annular space between it and the inner wall of the casing (a), which
space when the tyre is inflated may again be closed by the screwed holder (k)
being again screwed upwards with the object of obtaining a perfectly true metallic
joint, substantially as herein before described.
2. In a back pressure valve of the kind described, forming the valve cone (o)
and the tapered boring of the casing (a) of a different taper, whereby, on the clos-

page_text: ing of the valve, a joint is formed on only an annular line with the object of
obtaining an absolutely certain hermetic closing of the valve which cannot be.
obtained with the conical metallic surface joints at present employed, substan-
tially as herein before described.