AU719902B3

AU719902B3 - Pressure relief valve

Info

Publication number: AU719902B3
Application number: AU53534/99A
Authority: AU
Inventors: Stephen John Furlonger; Vaughan Grant
Original assignee: STAUN Pty Ltd
Current assignee: STAUN Pty Ltd
Priority date: 1999-10-07
Filing date: 1999-10-07
Publication date: 2000-05-18
Anticipated expiration: 2005-10-07

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A PETTY PATENT Name of Applicants: Actual Inventors: VAUGHAN GRANT and STEPHEN JOHN

FURLONGER

VAUGHAN GRANT and STEPHEN JOHN

FURLONGER

Address for Service: Invention Title: CULLEN CO., Patent Trade Mark Attorneys, 240 Queen Street, Brisbane, QId. 4000, Australia.

PRESSURE RELIEF VALVE Details of Associated Provisional Applications: The following statement is a full description of this invention including the best method of performing it known to us: PRESSURE RELIEF VALVE TECHNICAL FIELD This invention relates to pressure relief valves and has particular relevance to valves suitable for lowering pressures within pneumatic tyres.

BACKGROUND ART It is important for motorists to regularly check that tyre pressures are even and in accordance with the specified pressures for particular driving conditions and circumstances.

Most service stations provide a free air service where motorists are able to check their air pressures and if necessary make adjustments to same.

Whilst increasing tyre pressures is a relatively straight forward matter, reducing pressures to a required level requires the motorist to depress the needle of a two way valve of each tyre to allow air to bleed and then to recheck with a pressure gauge that an appropriate pressure has been reached.

Most four wheel drive and terrain vehicles are designed to be driven in off road situations with lower than normal tyre pressures.

Because the off road usages are generally in remote areas where air pumps and gauge facilities are unlikely to be available, it is necessary for him to manually bleed off air from each tyre and to constantly check with a gauge the status of each tyre during the process.

It is easy for a motorist in these circumstances to inadvertently reduce the pressure to below the required rate. It would be convenient in these circumstances for motorists to have available a pressure relief valve which can be applied to the valve of each tyre of his vehicle and which ensure that the exact lower tyre pressure he requires is achieved accurately without the danger of deflation below an acceptable level.

It is an object of the present invention to provide a pressure relief valve which can be applied to the valve of a pneumatic tyre and which will allow accurate deflation of the tyres to a predetermined level.

Further objects and advantages of the present invention will become apparent on the ensuring description which is given by way of example.

DISCLOSURE OF INVENTION According to the present invention there is provided a pressure relief valve comprising; a substantially elongate valve body having an internal air bleed chamber, an adjacent air bleed passage and a tyre valve engagement means, a cap adjustably attached to an open end of the air bleed chamber, a valve within the air bleed chamber said valve having a valve head which is adapted to engage with a valve seat located between the air bleed chamber and the air bleed passage and an extending valve stem the free end of which extends to and engages with a centralised aperture in the cap, a biasing spring mounted on the valve stem which is compressed between the cap and the valve head and applies a continuous closing bias to the valve head, and a strike pin extending from the tyre valve engagement means the arrangement and construction being such that when the valve body is coupled to a two-way valve of a pneumatic tyre and the strike pin contacts a needle within the two-way valve pressures within the tyre can be reduced in proportion with a predetermined compression applied to the spring, wherein the air bleed chamber and cap can have complimentary external and internal threads and the compression of the spring of the valve is adjusted according to the degree that the cap is advanced on the air bleed chamber thread.

An internally threaded lock washer can be mounted on the bleed chamber thread beneath the cap.

The air bleed passage can be provided by one or more apertures which allow air bleed from a tyre valve into the air bleed chamber.

The valve and valve head can be moulded in plastics.

BRIEF DESCRIPTION OF THE DRAWINGS Aspects of the present invention will now be described by way of example only with reference to the accompanying drawings in which; Figure 1 is a bottom view of a pressure relief valve in accordance with one aspect of the present invention, and Figure 2 is a side view of a pressure relief valve of Figure 1, and Figure 3 is a plan view of the pressure relief valve of Figure 1, and Figures 4 and 4a are full and partial cross sections respectively of the valve of the present invention taken at IV:IV of Figure 3.

With respect to the drawings a pressure relief valve in accordance with the present invention can comprise a substantially elongate valve body generally indicated by arrow 1 having an internal bleed chamber 2 and adjacent air bleed passage 3 and tyre valve engagement means 4.

The valve body is provided with a cap 5 which is adjustably mounted to an open end of the air bleed chamber 2.

A valve generally indicated by arrow 6 is disposed centrally within the air bleed chamber said valve having a valve head 7 which is adapted to engage and seal a valve seat 8 located between the air bleed chamber 2 and the air bleed passage 3 and an extending valve stem 9 the free end 9a of which extends to and is reciprocal within a centralised aperture in the cap A biasing compression spring 11 is mounted on the valve stem 9 and the spring is compressed between the cap 5 and the valve head 7 and applies a constant closing bias to the valve.

At the base of the air bleed chamber 3 there is provided one or more air passages 12 are provided and a centralised strike pin 13 extends outwardly the arrangement and construction being such that when the valve body 1 is coupled to a two way valve 14 and the strike pin 13 contacts the needle 15 of the valve pressures within the tyre (associated with the valve 14) can be reduced in proportion compression applied to the spring.

The air bleed chamber 2 and the cap 5 have complimentary external and internal threads 16 so that the position of the cap and thus the pressure on the spring can be adjusted to predetermined levels.

A locking washer 17 can also be fitted to the thread 16 to secure the cap in its desired position.

As the cap is wound off the thread 16 a predetermined distance pressure on the spring 11 is reduced accordingly. The surfaces of the thread and/or body or cap be marked to assist the user to select pressure ranges for the position and therefore the pressure on the compression spring can be adjusted by the use of a gauge or the like equating the distance S from with specific pressures.

The internal walls of the engagement means 4 can be provided with a standardised internal thread which matches with the standard external thread of a two way valve.

The body 1 of the valve can be moulded or fabricated or machine from metal.

The integrity of the valve seal can be enhanced by the provision of a compressable seal 18 fixed on the stem 9 below the valve head 7.

The present invention allows accurate adjustment of tyre pressures, can be readily preset the user and reduce pressures in tyres can be elevated by the user by simply removing the relieve valves and re-inflating the tyres.

Aspects of the present invention have been described by way of example only and it will be appreciated that modifications and additions thereto may be made without departing from the scope thereof as defined in the appended claims.

Claims

1. A pressure relief valve comprising; a substantially elongate valve body having an internal air bleed chamber, an adjacent air bleed passage and a tyre valve engagement means, a cap adjustably attached to an open end of the air bleed chamber, a valve within the air bleed chamber said valve having a valve head which is adapted to engage with a valve seat located between the air bleed chamber and the air bleed passage and an extending valve stem the free end of which extends to and engages with a centralised aperture in the cap, a biasing spring mounted on the valve stem which is compressed between the cap and the valve head and applies a continuous closing bias to the valve head, and a strike pin extending from the tyre valve engagement means the arrangement and construction being such that when the valve body is coupled to a two-way valve of a pneumatic tyre and the strike pin contacts a needle within the two-way valve pressures within the tyre can be reduced in proportion with a predetermined compression applied to the spring, wherein the air bleed chamber and cap have complimentary external and internal threads and the compression of the spring of the valve is adjusted according to the degree that the cap is advanced on the air bleed chamber thread.

2. A pressure relief valve as claimed in claim 1 having an internally threaded lock washer mounted on the bleed chamber thread beneath the cap.

3. A pressure relief valve as claimed in claim 1 or claim 2 with reference to the drawings. DATED this 21 t day of March 2000 Vaughan GRANT and Stephen John FURLONGER SBy their Patent Attorneys CULLEN CO.