GB2026137A - A cap for a valve or other outlet - Google Patents

Abstract

A cap 1 for a valve or other outlet 4 from pressurized tanks, has a chamber 6 defined between the plug bottom 2 and a ridges, said chamber 6 accommodating a seal 7 which rotates within the cap when the latter is screwed down onto the outlet. The chamber may be permanently lubricated with suitable oils or fats. The cap may be moulded in plastics over a pin which is thereafter withdrawn. <IMAGE>

Description

SPECIFICATION A plug for valve or other outlet from pressurized tank and method of manufacturing the same.

This invention relates to a plug for valve or other outlet from pressurized tanks, particularly plugs made of plastic material.

Plugs for this use were made of metal; in this case such plugs comprise a seal seating, so that the seal is retained within the plug which is provided with a particular chamber, the latter being defined by a narrow annular edge retaining the seal therein. The operation of these metal plugs is unexceptionable, but unfortumately are too expensive. In order to reduce costs, attempts were made to produce several types of plastic plugs, which however or are not provided with a seal, or are provided with a rubber seal that is clamped in different ways in order not to be dislodged.

It is the object of the present invention to provide a plastic plug, capable of retaining a seal therein, but designed so as to rotate within the cap when the latter is screwed down. Thereby the seal is allowed to perform successufully its task without causing any anomalous twist which could prejudicial to the perfect sealing of the assembly or damage the seal itself.

The above mentioned object has been accomplished by providing a plug having a chamber with conical walls tapering in the direction of the open end of the plug, which chamber retains a seal, the portion of which contacting the plug bottom is of a shape corresponding thereto, so as to fit in the chamber and remain therein without being clamped.

The present invention also provides a method of manufacturing the above described plug, according to which the plug molding is carried out by a pull pin enabling to mold the plug in one piece, while having the latter a maximum diameter of the inner chamber which is larger than the diameter of its portion closer to the open end of the plug.

The invention will now be more clearly explained with reference to an exemplary embodiment as shown in the single figure of the accompanying drawings, which is a sectional view showing a plug according to the present invention as fitted on the head of a valve or other outlet from a tank.

A plug according to the present invention has been generally denoted at 1. This plug comprises an upper bottom 2 and side walls 3, in which longitudinal grooves 3a are externally provided for aiding in screwing and unscrewing. Internally of wall 3, a thread 3b is provided, which matches with a thread 4c of a valve body 4, or of any other tank outlet, which has an outer thread 4c.

The particular peculiarity of a plug according to the present invention is to be found in the ridge 5 circumferentially extending internally of the plug above the threaded zone 3b, that is between said zone 3b and the closed bottom 2 of the plug.

Thereby, between said ridge 5 and bottom 2 a chamber 6 is created, which at the top near said closed bottom 2 has a maximum diameter which is less than the diameter of the crest or tip of threads 3b. The side walls 6a of chamber 6 then connected with said ridge 5 following a somewhat conical pattern, the cone apex facing the open end of the plug. This chamber can accomodate a seal 7 of outer shape 7a matching the shape of chamber 6. Thus, at the top it is of frusto-conical shape, as this portion is designed to penetrate into chamber 6, while its lower portion, that is zone 7b for sealing is preferably also of conical external pattern, but facing in opposite direction to the tapering of the portion for insertion in chamber 6. Thus, the seal 7 can contact with a surface 4b of the outlet end 4 of a tank or a valve having a diameter which is very similar to that of thread 4c.

In order to develop a plastic plug 1, as described in the present invention, the use should be provided during the molding operation of a pull pin which penetrates into the plug matrix, so that upon formation of the plug the pin can be removed by elasticity from the plug. The taper of wall 6a for connecting the chamber buttom with the ridge 5 should be designed so that the pin can be removed or drawn out in accordance with the material by which the plug is made.

To accomplish this, the maximum diameter of chamber 6 should not be larger than the thread crest or tip, so that the pull pin would not damage the threads when being removed or drawn out.

During assembly, in order to further improve the seal rotation, said chamber 6will be permanently lubricated with suitable oils or fats that cannot be absorbed by the rubber forming said seal 7.

Obviously, the present invention embraces all of those detail changes that do not alter the basic concept thereof.

1. A plug for valve or other outlet from pressurized tanks having a chamber between the plug bottom and its threaded zone hich is defined by a ridge, said ridge being smoothly connected to said bottom, and said chamber accomodating a seal of rotatable type which is of a shape corresponding to that of the chamber at its zone which fits in the chamber.

2. A plug according to Claim 1, wherein the maximum diameter of the chamber is less than the diameter of the thread crest or tip of the plug thread.

3. A plug according to Claim 1 or 2, wherein said chamber is filled up with suitable oils or fats that cannot be absorbed by the rubber of said seal, so as to further aid in the rotation of said seal.

4. A plug according to any Claims 1-3, having a seal, the outer surface of which beyond the zone which is received in the plug chambers widens out to the diameter of the zone on which the sealing is to be provided as desired.

5. A process for the manufacture of a plug according to Claim 1 or 2, wherein the use of a pull pin is provided, said pull pin being removed or drawn out as soon as the plug is molded.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION A plug for valve or other outlet from pressurized tank and method of manufacturing the same. This invention relates to a plug for valve or other outlet from pressurized tanks, particularly plugs made of plastic material. Plugs for this use were made of metal; in this case such plugs comprise a seal seating, so that the seal is retained within the plug which is provided with a particular chamber, the latter being defined by a narrow annular edge retaining the seal therein. The operation of these metal plugs is unexceptionable, but unfortumately are too expensive. In order to reduce costs, attempts were made to produce several types of plastic plugs, which however or are not provided with a seal, or are provided with a rubber seal that is clamped in different ways in order not to be dislodged. It is the object of the present invention to provide a plastic plug, capable of retaining a seal therein, but designed so as to rotate within the cap when the latter is screwed down. Thereby the seal is allowed to perform successufully its task without causing any anomalous twist which could prejudicial to the perfect sealing of the assembly or damage the seal itself. The above mentioned object has been accomplished by providing a plug having a chamber with conical walls tapering in the direction of the open end of the plug, which chamber retains a seal, the portion of which contacting the plug bottom is of a shape corresponding thereto, so as to fit in the chamber and remain therein without being clamped. The present invention also provides a method of manufacturing the above described plug, according to which the plug molding is carried out by a pull pin enabling to mold the plug in one piece, while having the latter a maximum diameter of the inner chamber which is larger than the diameter of its portion closer to the open end of the plug. The invention will now be more clearly explained with reference to an exemplary embodiment as shown in the single figure of the accompanying drawings, which is a sectional view showing a plug according to the present invention as fitted on the head of a valve or other outlet from a tank. A plug according to the present invention has been generally denoted at 1. This plug comprises an upper bottom 2 and side walls 3, in which longitudinal grooves 3a are externally provided for aiding in screwing and unscrewing. Internally of wall 3, a thread 3b is provided, which matches with a thread 4c of a valve body 4, or of any other tank outlet, which has an outer thread 4c. The particular peculiarity of a plug according to the present invention is to be found in the ridge 5 circumferentially extending internally of the plug above the threaded zone 3b, that is between said zone 3b and the closed bottom 2 of the plug. Thereby, between said ridge 5 and bottom 2 a chamber 6 is created, which at the top near said closed bottom 2 has a maximum diameter which is less than the diameter of the crest or tip of threads 3b. The side walls 6a of chamber 6 then connected with said ridge 5 following a somewhat conical pattern, the cone apex facing the open end of the plug. This chamber can accomodate a seal 7 of outer shape 7a matching the shape of chamber 6. Thus, at the top it is of frusto-conical shape, as this portion is designed to penetrate into chamber 6, while its lower portion, that is zone 7b for sealing is preferably also of conical external pattern, but facing in opposite direction to the tapering of the portion for insertion in chamber 6. Thus, the seal 7 can contact with a surface 4b of the outlet end 4 of a tank or a valve having a diameter which is very similar to that of thread 4c. In order to develop a plastic plug 1, as described in the present invention, the use should be provided during the molding operation of a pull pin which penetrates into the plug matrix, so that upon formation of the plug the pin can be removed by elasticity from the plug. The taper of wall 6a for connecting the chamber buttom with the ridge 5 should be designed so that the pin can be removed or drawn out in accordance with the material by which the plug is made. To accomplish this, the maximum diameter of chamber 6 should not be larger than the thread crest or tip, so that the pull pin would not damage the threads when being removed or drawn out. During assembly, in order to further improve the seal rotation, said chamber 6will be permanently lubricated with suitable oils or fats that cannot be absorbed by the rubber forming said seal 7. Obviously, the present invention embraces all of those detail changes that do not alter the basic concept thereof. CLAIMS

1. A plug for valve or other outlet from pressurized tanks having a chamber between the plug bottom and its threaded zone hich is defined by a ridge, said ridge being smoothly connected to said bottom, and said chamber accomodating a seal of rotatable type which is of a shape corresponding to that of the chamber at its zone which fits in the chamber.

2. A plug according to Claim 1, wherein the maximum diameter of the chamber is less than the diameter of the thread crest or tip of the plug thread.

3. A plug according to Claim 1 or 2, wherein said chamber is filled up with suitable oils or fats that cannot be absorbed by the rubber of said seal, so as to further aid in the rotation of said seal.

4. A plug according to any Claims 1-3, having a seal, the outer surface of which beyond the zone which is received in the plug chambers widens out to the diameter of the zone on which the sealing is to be provided as desired.

5. A process for the manufacture of a plug according to Claim 1 or 2, wherein the use of a pull pin is provided, said pull pin being removed or drawn out as soon as the plug is molded.