GB1567402A - Pressure control apparatus - Google Patents

Description

(54) PRESSURE CONTROL APPARATUS (71) We, ROBERT BOSCH GmbH, a German Company of Postfach 50, 7000 Stuttgart 1, Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to pressure control apparatus for providing a signal when the pressure in either of two gas containers (such as vehicle tyres) falls below a preset minimum and for isolating that container from communication with the other.

According to the invention, there is provided a pressure control apparatus for providing a signal when the pressure in either of two gas containers falls below a preset minimum and for isolating that container from communication with the other, which comprises: a chamber, first and second connections communicating with the chamber for connection to two gas containers, a third connection communicating with the chamber for connection to a source of gas pressure for supplying gas through the chamber to the containers, the third connection including a non-return valve therefor, a gas-pressure sensitive device communicating with the chamber for providing a signal when the gas pressure in the chamber falls below a preset minimum, and wherein a valve member is provided in the chamber and is arranged to close one only of the first and second connections when the pressure in the chamber falls below the said minimum.

In order that the invention may be more fully understood, one embodiment thereof will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a front view of the embodiment of the invention; Figure 2 is a section along the line II-II of Figure 1; Figure 3 is a partial section along the line III-III of Figure 1; Figure 4 shows the apparatus mounted for use on a road vehicle.

Referring to the drawings, the pressure control apparatus has a housing portion 10 which is closed fluid-tight by a cover 11. A central cylindrical space 12 which is closed at its open end by a diaphragm 13, is arranged in the housing 10. A spring 16 in the space 12 between two spring-cups 14, 15, acts on the diaphragm 13. The pre-tension of the spring 16 is adjustable by means of a screw 17, arranged in the housing 10, which acts on the spring cup 14.

Three bores 19, 20, 21 are arranged in the housing 10 radially externally of the cylindrical space 12, the axes of which extend parallel to that of the space 12. A tyre inflating valve 23 (i.e. a non-return valve) is arranged in an extension piece 22 in the bore 19. An extension piece 26 is likewise arranged in the bore 20, to which is attached a pressure hose 27 which leads to a first tyre 28. An extension piece 29 is arranged in the bore 21 from which a pressure hose 30 leads to the second tyre 31.

An annular chamber or space 33, the outer diameter of which is large enough for it to extend up to the bores 19 to 21, is arranged in the cover 11. A raised portion 34 into the centre of which issues a bore 35, is located in the centre of the annular space. The diaphragm 13 is applied to the said bore by the force of the spring 16. The bore 35 issues into a transverse bore 36 into which in its turn issues a bore 37 which is in communication with the bore 21.

The cover 11 has a cylindrical extension 38 provided with a central blind bore 39 in which is located an extension piece 40. A gas-pressure sensitive switch 41 is connected to the said extension piece. An inclined bore 42 extends from the base of the bore 39 into the annular space 33. A throttle member 43 is arranged at the upper end of the bore 20.

The force of the spring 16 is chosen to correspond to the required minimum tyre pressure. This value can be adjusted by means of the screw 17. During pumping up of the tyres through the extension piece 22 and the valve 23, the air pressure entering into the bore 19 and the annular space 33 presses on the diaphragm 13 which, at the required response pressure, is raised from the end of the bore 35. The inflating pressure is then distributed to all the above-mentioned bores which permits the simultaneous pumping up of both tyres to the desired tyre pressure.

If the pressure drops in one of the two tyres, the air pressure in the other tyre is likewise reduced, but only to a predetermined value. When this value is reached, the spring 16 pushes the diaphragm 13 on to the end of the bore 35 and closes the latter. At this instant, communication between the bores 20 and 21, that is to say between the two tyres, is cut off so that the one intact tyre is not deflated any further. The presure switch 41 always responds at about 0.5 bars above the said predetermined pressure. Its purpose is to provide a signal to initiate an exact switching procedure when a critical air pressure is reached, for the purpose of monitoring the air pressure in the tyres.

WHAT WE CLAIM IS: 1. Pressure control apparatus for providing a signal when the pressure in either of two gas containers falls below a preset minimum and for isolating that container from communication with the other, which comprises: a chamber, first and second connections communicating with the chamber for connection to two gas containers, a third connection communicating with the chamber for connection to a source of gas pressure for supplying gas through the chamber to the containers, the third connection including a non-return valve therefor, a gas-pressure sensitive device communicating with the chamber for providing a signal when the gas pressure in the chamber falls below a preset minimum, and wherein a valve member is provided in the chamber and is arranged to close one only of the first and second connec tions when the pressure in the chamber falls below the said minimum.

2. Apparatus according to claim 1 wherein the valve is a diaphragm valve.

3. Apparatus according to claim 2 wherein the diaphragm valve is loaded by an adjustable spring which urges the diaphragm towards the first or the second connection.

4. Pressure control apparatus for provid ing a signal when the pressure in either of two gas containers falls below a preset minimum and for isolating that container from com munication with the other, substantially as herein described in Figures 1 to 4 of the accompanving drawings.

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

Claims (4)

**WARNING** start of CLMS field may overlap end of DESC **. The force of the spring 16 is chosen to correspond to the required minimum tyre pressure. This value can be adjusted by means of the screw 17. During pumping up of the tyres through the extension piece 22 and the valve 23, the air pressure entering into the bore 19 and the annular space 33 presses on the diaphragm 13 which, at the required response pressure, is raised from the end of the bore 35. The inflating pressure is then distributed to all the above-mentioned bores which permits the simultaneous pumping up of both tyres to the desired tyre pressure. If the pressure drops in one of the two tyres, the air pressure in the other tyre is likewise reduced, but only to a predetermined value. When this value is reached, the spring 16 pushes the diaphragm 13 on to the end of the bore 35 and closes the latter. At this instant, communication between the bores 20 and 21, that is to say between the two tyres, is cut off so that the one intact tyre is not deflated any further. The presure switch 41 always responds at about 0.5 bars above the said predetermined pressure. Its purpose is to provide a signal to initiate an exact switching procedure when a critical air pressure is reached, for the purpose of monitoring the air pressure in the tyres. WHAT WE CLAIM IS:

1. Pressure control apparatus for providing a signal when the pressure in either of two gas containers falls below a preset minimum and for isolating that container from communication with the other, which comprises: a chamber, first and second connections communicating with the chamber for connection to two gas containers, a third connection communicating with the chamber for connection to a source of gas pressure for supplying gas through the chamber to the containers, the third connection including a non-return valve therefor, a gas-pressure sensitive device communicating with the chamber for providing a signal when the gas pressure in the chamber falls below a preset minimum, and wherein a valve member is provided in the chamber and is arranged to close one only of the first and second connec tions when the pressure in the chamber falls below the said minimum.

2. Apparatus according to claim 1 wherein the valve is a diaphragm valve.

3. Apparatus according to claim 2 wherein the diaphragm valve is loaded by an adjustable spring which urges the diaphragm towards the first or the second connection.

4. Pressure control apparatus for provid ing a signal when the pressure in either of two gas containers falls below a preset minimum and for isolating that container from com munication with the other, substantially as herein described in Figures 1 to 4 of the accompanving drawings.