PNEUMATIC PRESSURE GAUGE

MANOMETRE PNEUMATIQUE

English Abstract

ABSTRACT
An improved pneumatic pressure gauge used in
inflating a pneumatic tire comprises an adapter means
having a gas passage extending from a gas inlet end to a
gas outlet end, and a gauge casing connected integrally to
the adapter member. The gauge casing includes a gauge
chamber, an opening intercommunicating the gas passage and
the gauge chamber, a control chamber communicated with the
gauge chamber, and a gas release passage opened to
atmosphere and communicated with the control chamber. A
first valve means is disposed to close the communication
between the gas passage and the gauge chamber, and a
second pressure responsive valve means is disposed in the
control chamber to close the communication between the
control chamber and the gas release passage. The valve
means are opened when the pressure in the tire or the gas
passage exceeds the predetermined pressure.

Claims

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THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A pneumatic pressure gauge comprising:
(a) a gauge casing comprising first and second
cylindrical portions threadedly coupled at first ends
thereof;
(b) first support means rigidly connected to a
second end of said first cylindrical portion, said first
support means having a passageway therethrough which is in
communication with a bore of said first cylindrical
portion;
(c) second support means connected to a second end
of said second cylindrical portion, said second support
means having a first passageway therethrough which is in
communication with a bore of said second cylindrical
portion;
(d) a pressure responsive valve means having a first
position whereat said valve means abuts said first support
means whereby said passageway in said first support means
is closed, and a second position whereat said valve means
does not abut said first support means, whereby said
passageway in said first support means is open, said valve
means being displaced from its first position to its
second position in response to a predetermined pressure in
said passageway in said first support means,
(e) a pressure responsive diaphragm means made of
elastic material and having a peripheral portion secured
sealingly to said second support means,
wherein said second support means comprises a
substantially annular base portion, a first tubular
portion rigidly connected to said base portion and having

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a bore, a second tubular portion rigidly connected to said
base portion and having a bore, said first tubular portion
being arranged in said bore of said second tubular
portion, and a second passageway which is in communication
with said bore of said first tubular portion and a space
external to said second cylindrical portion, said
diaphragm means being secured to an end of said second
tubular portion and having a first position whereat said
diaphragm means abuts an end of said first tubular
portion, whereby said end of said first tubular portion is
closed, said first and second tubular portions, said base
portion and said diaphragm means defining an annular
control chamber when said diaphragm means is in its first
position, said control chamber being in communication with
said first passageway of said second support means,
whereby said diaphragm is displaced from its first
position to a second portion in response to said
predetermined pressure in said passageway of said first
support means, control chamber and said bore of said first
tubular portion being in communication when said diaphragm
means is in its second position.
2. The pneumatic pressure gauge as defined in claim 1,
further comprising a clamping means fixedly arranged
relative to said second cylindrical portion, said clamping
means having an annular projection in contact with said
diaphragm means for holding said diaphragm means against
said end of said first tubular portion, the diameter of
said annular projection being greater than the diameter of
said end of said first tubular portion.
3. The pneumatic pressure gauge as defined in claim 1 or
2, further comprising a tubular adaptor means connected to
said gauge casing and having a gas inlet, a gas outlet and
a passageway extending between said gas outlet, said gas
passage being in communication with said passageway of
said first support means.

Description

1302728
BACKGROUND OF THE INVENTION
This invention relates to a pneumatic pressure gauge
used for a pneumatic tire, particularly to a pneumatic
pressure gauge having a pressure responsive means that can
release gas from the tire when the pressure to which the
tire is inflated exceeds a predetermined pressure.
It is a common practice to use a pressure gauge as
guidance in inflating a pneumatic tire. The pressure
gauge is applied to the tire when the pressure to which
the tire is inflated is assumed to be substantially a
required pressure. If the pressure is not right, it
should be adjusted by letting out or adding some gas.
Since pressure gauges available hitherto can merely
measure the pressure present in the tire, it is necessary
to detach and attach the pressure gauge again and again to
let out or add the gas so as to achieve a desired pressure
in the tire, The manipulation of such a pressure gauge is
rather inconvenient.
SUMMARY OF THE INVENTION
The present invention provides a pneumatic pressure
gauge which comprises: a gauge casing constituted of first
and second cylindrical portions threadedly coupled at
first ends thereof; first support means rigidly connected
to a second end of the first cylindrical portion and
having a passageway therethrough which is in communication
with a bore of the first cylindrical portion; second
support means connected to a second end of the second
cylindrical portion, the second support means having a
first passageway therethrough which is in communication
with a bore of the second cylindrical portion; a pressure
responsive valve means having a first position whereat the
valve means abuts the first support means whereby the
passageway in the first support means is closed, and a
second position whereat the valve means does not abut the

~ ~302728
first support means, whereby the passageway in the first
support means is open, the valve means being displaced
from its first position to its second position in response
to a predetermined pressure in the passageway in the first
support means; a pressure responsive diaphragm means made
of elastic material and having a peripheral portion
secured sealingly to the second support means; wherein the
second support means comprises a substantially annular
base portion, a first tubular portion rigidly connected to
the base portion and having a bore, a second tubular
portion rigidly connected to the base portion and having a
bore, the first tubular portion being arranged in the bore
of the second tubular portion, and a second passageway
which is in communication with the bore of the first
tubular portion and a space external to the second
cylindrical portion, the diaphragm means being secured to
and end of the second tubular portion and having a first
position whereat the diaphragm means abuts an end of the
first tubular portion, whereby the end of the first
tubular portion is closed, the first and second tubular
portions, the base portion and the diaphragm means
defining an annular control chamber when the diaphragm
means is in its first position, the control chamber being
in communication with the first passageway of the second
support means, whereby the diaphragm is displaced from its
first position to a second portion in response to the
predetermined pressure in the passageway of the first
support means, control chamber and the bore of the first
tubular portion being in communication when the diaphragm
means is in its second position.
In one aspect of the invention, a clamping means is
fixedly arranged relative to the second cylindrical
portion, the clamping means having an annular projection
in contact with the diaphragm means for holding the
diaphragm means against the end of the first tubular
portion, the diameter of the annular projection being
greater than the diameter of the end of the first tubular
portion.

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The present exemplary preferred embodiment will be
described in detail with reference to the accompanying
drawings, in which:
DETAILED DESCRIPTION OF THE DRAWINGS
Fig. 1 is a sectional view of a pneumatic pressure
gauge constructed according to the present invention; and
Fig. 2 is a perspective view of the pressure gauge of
Fig, 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the drawings, a pneumatic pressure gauge
1 is shown, including an adapter piece 2 which
incorporates parts to be connected to a hose of a
pneumatic pump and an inflating valve of a tire to be
inflated, and has a gas passage 6 extending from one end
to the other. To the adapter piece 2 is connected
integrally a pressure gauge casing 3. The gauge casing 3
is telescopic and is constituted of a first cylindrical
portion 7 which is connected to the adapter piece 2 and a
second portion 8 sleeved threadedly on the first portion
7. The outer periphery of the first cylindrical portion 7
is graduated.
At the top of the second portion 8 of the gauge
casing 3 is attached threadedly a cap 9 to close the
second portion 8. In the interior of the gauge casing 3
is disposed a support body 10 which divides the casing 3
into two regions 11 and 12. The support body 10 has a
first tubular portion 13 with a closed end 14 extending
axially into the region 11, a second tubular portion 15
with an open end extending axially into the region 12, and
a third tubular portion 16 with an open end extending
axially around said second tubular portion 15.
,:

130Z7Z~
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The region 11 defines a gauge chamber which is
communicated with the gas passage 6 of the adapter piece
through an opening 17 of the first portion 7 of the casing
3. Near the opening 17 is a valve seat 18 against which
is seated a valve plug 19 to interrupt the communication
between the gas passage 6 and the gauge chamber 11. The
valve plug 19 is biassed by a compression spring 20 which
in turn is affixed to the closed end 14 of the support
body 10. The valve plug 19 is biassed by a spring force
predetermined to be equivalent to the desired pneumatic
pressure to which a tire is to be inflated. According to
graduated marks of the first portion 7 of the casing 3,
the spring force can be adjusted by turning the second
portion 8 relative to the first portion 7 of the gauge
casing 3 so as to make the gauge 1 suitable for use in
determining and controlling different pneumatic pressures
of tires. The valve plug 19 is responsive to the
predetermined pressure of the gas passage 9 and can be
moved against the spring force to open the opening 17 when
the predetermined pressure is reached.
The support body 10 is provided with a diametral bore
21 opening at the periphery of the second portion 8 of the
casing 3, and an axial bore 22 intersecting the diametral
bore 21 and extending from the closed end 14 to the open
end of the second tubular portion 15 of the support body
10 .
A diaphragm valve member 23 which is made of a
rubber-like material is secured sealingly with its
circumferential portion to the open end of the third
tubular portion 16 of the support body 10, confining a
control chamber 24 between the diaphragm member 23 and the
support body 10. An axial bore 25 is arranged in the
support body 10 to communicate the gauge chamber 11 and
the control chamber 24.
A clamping member 26 which is formed intergrally with
the cap 9 extends axially into the region 12. The

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clamping member 26 has an annular end 27 to depress the
diaphragm member 23 against the open end of the second
tubular portion 15 of the support body 10. The diameter
of the annular end 27 is greater than that of the open end
of the second tubular portion 15 so that the diaphragm
member 23 contracts against or closes resiliently the open
end of the axial bore 22.
In operation, the adapter member 2 is connected to a
hose of a pump and an inflating valve of the tire to be
inflated. When the pressure in the tire and the gas
passage 6 exceeds a predetermined pressure, the valve plug
19 is actuated to an open position, permitting the excess
gas to flow into the gauge chamber 11 from the gas passage
6. The gas in the gauge chamber 11 then flows into the
control chamber 24 through the bore 25. When the pressure
in the control chamber 24 increases to that capable of
thrusting the central portion of the diaphragm member 23
to move away from the open end of the bore 22, the excess
gas escapes through the axial bore 22 and the diametral
bore 21. When the pressure is reduced, the diaphragm
member 23 returns to its normal closed position. Upon
continuous injection of the gas, the diaphragm member 23
vibrates at the open end of the second tubular portion 15
and produces sound to warn the operator to stop the
operation. It can be appreciated that the pressure in the
inflated tire will not exceed the desired predeterminèd
pressure even though the operator is neglectful.
With the invention thus explained, it is apparent
that various modifications and variations can be made
without departing from the scope of the invention. It is
therefore intended that the invention be limited as
indicated in the appended claims.

Representative Drawing