WO1996036861A1

WO1996036861A1 - Pressure sensing valve cap that permits the passage of air

Info

Publication number: WO1996036861A1
Application number: PCT/GB1996/001171
Authority: WO
Inventors: John Alexander Hines-Wragg
Original assignee: Hines Wragg John Alexander
Priority date: 1995-05-16
Filing date: 1996-05-16
Publication date: 1996-11-21
Also published as: GB9509840D0; AU5769596A

Abstract

A cap connectable to the valve stem of an inflatable body such as a tire of a vehicle. The cap is in two threadable parts (22, 24) and with another valve (42), so that it is not necessary to remove it. An inside lateral underpressure switch (72, 74) with a membrane (70) and plate (66) activates an inside transmitter (16) with battery (80) for remote alarm.

Description

PRESSURE SENSING VALVE CAP THAT PERMITS THE PASSAGE OF AIR

The present invention relates to pressure sensing devices, and particularly but not exclusively to devices for sensing the pressure inside inflatable bodies.

Inflatable bodies, when inflated are susceptible to deflation through failure of the valve or puncture of the body itself. Such deflation can often be hazardous, for example when the inflatable body is the tyre of a vehicle, the hull of a boat, or a float.

The term "pressure source" relates to any means that is pressurized or pressurizable , such as inflatable bodies, pressurized pipelines, pressurized vessels, pumps and the like .

According to the present invention there is provided a pressure sensing device connectable to a pressure source, and comprising a pressure sensor operable to sense the pressure from the source when the device is connected thereto and to cause a transmitter to transmit information relating to the pressure to remote signal means whereby to cause the said means to produce a signal relating to the pressure sensed.

Preferably the transmitter is operable to transmit electromagnetic waves, such as radiowaves and infrared radiation, across a space. Preferably the transmitter transmits information only when the pressure from the source falls below a predetermined value whereby to cause the signal means to produce a signal notifying the pressure drop.

Preferably the device comprises a housing defining a chamber providing communication between the pressure source and the sensor when the device is connected for use to the source. Preferably the housing comprises a first part sealingly connectable to the pressure source and a second part attachable, desirably sealingly, to the first part. The sensor is preferably located between the first and second parts, and is preferably secured to one of said parts, desirably with electrically non-conductive resin. The chamber is preferably substantially defined between the first part and the sensor. Preferably the first and second parts are releasably attachable to enable access to the sensor.

Preferably the sensor is electrically operable and may comprise part of an electrical circuit comprising a power source located preferably within the housing, and the transmitter. The sensor may comprise a member movable under the influence of pressure from the pressure source between a first condition in which the electrical circuit is broken to a second condition in which the electrical circuit is completed and the transmitter thereby connected to the power source. Preferably the member moves from the first condition to the second condition when the pressure from the pressure source drops below a predetermined value, the transmitter being operable upon completion of the electrical circuit.

Preferably the member comprises a diaphragm mounted across an opening in the first part and which is movable under pressure. The diaphragm may comprise a rigid portion which may be electrically conductive. One or more electrical connectors may be provided on the member to be cooperable with one or more corresponding connector(s) in the circuitry to complete the electrical circuit when the member is in said second condition. The connector(s) may be comprised in the rigid portion, and the said corresponding connector(s) preferably fixed in position .

A timing device may be provided to control the duration and desirably frequency of the transmitter's operation upon the member assuming the second condition. Preferably a second chamber is defined between the first and second parts in which the electric circuitry is located, and which is preferably not in communication - A -

with the said chamber.

Preferably the signal means is locatable to be readily visible by a user of the device, and may give one or both of audio and visual pressure related signals when activated by the transmitter.

The device may comprise an attachment formation to enable attachment of further apparatus to the device. Preferably the attachment formation comprises a valve which remains closed until further apparatus is attached to the attachment formation. Preferably the device is so formed so as not to significantly interfere with the normal operation of any further apparatus attached thereto, with the pressure source. Preferably the device enables pressure to be supplied therethrough to the pressure source, for example to pressurize the source.

The device is preferably connectable to a valve of an inflatable body, such as a tyre. Preferably the device comprises a pressure release formation to release the valve of the inflatable body to provide communication between the pressure inside the body and the chamber. Preferably the device comprises a portion permitting connection of the device to the valve. The release formation may comprise a projection extending from the entrance to the chamber toward the connecting portion to be contactable with a part of the valve to open the valve and release pressure from the pressure source into the chamber as the device is connected to the valve. Preferably the device is so constructed to enable the device to remain on the valve of a rotating wheel without significantly adversely affecting the balance of the wheel .

An embodiment of the present invention will now be described by way of example only, with reference to the accompanying drawings, in which:-

Fig. 1 is a cross-sectional view of a device according to the present invention, attached to a valve of an inflatable body; and

Fig. 2 is a view of the device of Fig. 1 in the direction A-A.

Referring to the drawings, a pressure sensing device 10 is connectable to a pressure source 12 and comprises a pressure sensor shown generally at 14 operable to sense the pressure from the source 12 when the device 10 is connected thereto, and to cause a transmitter 16 to transmit information relating to the pressure to remote signal means 18 operable to produce a signal relating to the pressure sensed.

In more detail, the device 10 comprises a housing 20 having a first part 22 and a second part 24. The first part 22 comprises a cylindrical base 26 and a generally cylindrical portion 28 of smaller diameter extending centrally from one side of the base 26. A threaded recess 30 is provided in the base 26 to extend from the other side of the base 26 to communicate with a central space 32 in the cylindrical portion 28 via an aperture 34. A valve releasing member 36 is located generally centrally in the aperture 34 to extend into the threaded recess 30. Webs 38 mount the releasing member 36 centrally in the aperture 34, whilst providing for communication between the threaded recess 30 and the central space 32.

The threaded recess 30 is operable to threadedly engage a valve stem S (shown in dotted outline) of an inflatable body such as a tyre, as will be described. An annular seal 40 is provided at the internal end of the recess 30 against which the valve stem S of the inflatable body is sealingly locatable.

The end 42 of the cylindrical portion 28 remote from the base 26 comprises a valve 44 similar to a valve V in the valve stem S of the inflatable body. The outside of the end 42 is also threaded with a thread 46 similar to that on the valve stem S, such that apparatus connectable to the valve stem S of the inflatable body is similarly connectable to the device 10.

The second part 24 of the device 10 is generally cylindrical with one open end 50, and the other end 47 thereof closed except for a smaller diameter central aperture 48. A thread 52 is provided around the inside of the open end 50 which is engagable with a cooperable thread 54 on the base 26 to permit threaded attachment of the second part 24 to the first part 22. An annular seal 56 is provided on an outward step 57 of the first part 22 to provide sealed attachment of the first and second parts 22,24. When the parts 22,24 are attached together, the cylindrical portion 28 extends through the central aperture 40 such that the thread 46 is accessible from outside of the device 10. An annular formation 58 is provided around the outside of the cylindrical portion 28 part way along the length thereof to locate a further annular seal 60 sealingly engagable between the annular formation 58 and the end 46 of the second part 24.

The sensor 14 is sealingly bonded over an opening 62 in the cylindrical portion 28 by resin 64 or other suitable adhesive. The sensor 14 generally comprises an electrically conductive plate 66 resiliently connected to a frame 68 (which is bonded to the cylindrical portion 28 of the first part 22) by a resilient membrane 70. Two generally 'L' shaped electrical contacts 72 extend from the plate 66 generally toward two further generally 'L' shaped electrical contacts 74 which comprise part of an electrical circuit. The contacts 72,74 are arranged such that they overlap and thereby are contactable as will be described. The contacts 74 are connected via two electrical wires 76 to a timer 78 which in turn is connected to the transmitter 16. A battery 80 is connected between the transmitter 16 and the timer 78, and provides the electrical power source when the contacts 72,74 are in electrical contact, as will be described.

The transmitter 16 is operable to transmit radio- waves or infrared radiation as shown diagrammatically at W to remote signal means 18, under the control of the timer 78, when the contacts 72,74 are in contact and electrical power is thus supplied thereto. The timer 78 is operable to control both the duration of operation of the transmitter 16 and also the frequency of operation. The signal means 18 is operable to receive the radiowaves transmitted by the transmitter 16 and to produce either an audio signal via a speaker 82 or a visual signal or display via a light emitting component 84, or both. It is to be appreciated that any suitable signal can be generated to alert an observer.

In use, the device 10 is sealingly connected to an inflatable body, for example by threaded connection to a valve stem S of a tyre for a vehicle (not shown). As the device 10 is threadedly connected to the stem S, the valve releasing member 36 urges the valve plunger P of the valve V into an open condition, to put the device 10 into communication with the tyre. Pressurized air from within the tyre moves into a chamber 86 of the device 10 defined generally between the first part 22, the valve 44 and the pressure sensor 14. A second chamber 88 defined between the first and second parts 22,24 and the sensor 14 is not in communication with the said chamber 86 and houses the components of the electrical circuit as described above.

When pressure equilibrium is reached, the pressure within the chamber 86 corresponds to that within the inflatable body (tyre). If that pressure is above a predetermined minimum pressure, then the plate 66 will be urged away from the opening 62 against the resilience of the membrane 70, such that the contacts 72,74 are spaced, and the electrical circuit is broken. In this condition the transmitter is inoperable.

If the pressure within the inflatable body decreases, then the pressure within the chamber 86 decreases accordingly, and if the pressure decreases below the predetermined minimum, then the resilient membrane 70 will relax and cause the plate 66 to move toward the aperture 62, the contacts 72,74 will touch, the circuit will be complete, and electrical power will be supplied to the timer 78 and the transmitter 16, and radiowaves W will be transmitted to the signal means 18. The signal means 18 is located to be visible and/or audible upon activation by the radiowaves W, and is preferably located in the dashboard or another convenient location in the vehicle to which the device 10 is connected. Upon receipt of the radiowaves W, the signal means 18 generates a signal to advise a person in the vehicle that the pressure within the tyre has dropped below a safe level, such that appropriate action should be taken.

It is to be appreciated that the present invention provides a significant safety feature. It enables a driver of a vehicle to slow down or stop before the pressure in a tyre becomes hazardously low. It is also to be appreciated that the safety aspect is applicable in many other instances, for example when the device is used on inflatable boats, floats or any other suitable apparatus. The device could be used to monitor the pressure in pressurized vessels such as gas cylinders, and one application of this may be in the medical field or any other field in which the maintenance of pressure is important.

Various modifications may be made without departing from the spirit or scope of the present invention. The electrical circuitry may comprise a printed circuit board. The device 10 may be adapted to be connectable to a pressure source via intermediary devices or instru¬ ments, such as extension devices, and measuring devices. The device may be formed to be connectable to other pressure sources, such as pressurized pipelines, pumps etc .

Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims

1. A pressure sensing device connectable to a pressure source, and comprising a pressure sensor operable to sense the pressure from the source when the device is connected thereto and to cause a transmitter to transmit information relating to the pressure to remote signal means whereby to cause the said means to produce a signal relating to the pressure sensed.

2. A device as claimed in claim 1, in which the transmitter is operable to transmit electromagnetic waves, such as radiowaves and infrared radiation, across a space.

3. A device as claimed in claim 1 or claim 2, in which the transmitter transmits information only when the pressure from the source falls below a predetermined value whereby to cause the signal means to produce a signal notifying the pressure drop.

4. A device as claimed in any preceding claim, in which the device comprises a housing defining a chamber providing communication between the pressure source and the sensor when the device is connected for use to the source.

5. A device as claimed in claim 4, in which the housing comprises a first part sealingly connectable to the pressure source and a second part attachable to the first part.

6. A device as claimed in claim 5, in which the sensor is located between the first and second parts.

7. A device as claimed in claim 5 or claim 6, in which the sensor is secured to one of said parts.

8. A device as claimed in claim 7, in which the sensor is secured with electrically non-conductive resin.

9. A device as claimed in any of claims 5 to 8, in which the chamber is substantially defined between the first part and the sensor.

10. A device as claimed in any of claims 5 to 9, in which the first and second parts are releasably attachable to enable access to the sensor.

11. A device as claimed in any preceding claim, in which the sensor is electrically operable.

12. A device as claimed in claim 11, in which the sensor comprises part of an electrical circuit comprising a power source and the transmitter.

13. A device as claimed in claim 12, in which the power source is located within the housing.

14. A device as claimed in any of claims 11 to 13, in which the sensor comprises a member movable under the influence of pressure from the pressure source between a first condition in which the electrical circuit is broken to a second condition in which the electrical circuit is completed and the transmitter thereby connected to the power source.

15. A device as claimed in claim 14, in which the member moves from the first condition to the second condition when the pressure from the pressure source drops below a predetermined value, the transmitter being operable upon completion of the electrical circuit.

16. A device as claimed in claim 14 or claim 15, in which the member comprises a diaphragm mounted across an opening in the first part and which is movable under pressure.

17. A device as claimed in claim 16, in which the diaphragm comprises a rigid portion.

18. A device as claimed in claim 17, in which the rigid portion is electrically conductive.

19. A device as claimed in any of claims 14 to 18, in which one or more electrical connectors is provided on the member to be cooperable with one or more corresponding connector(s) in the circuitry to complete the electrical circuit when the member is in said second condition.

20. A device as claimed in claim 19, in which the connector(s) is/are comprised in the rigid portion.

21. A device as claimed in claim 19 or claim 20, in which the said corresponding connector(s) is/are fixed in position.

22. A device as claimed in any of claims 14 to 21, in which a timing device is provided to control the duration and desirably frequency of the transmitter's operation upon the member assuming the second condition.

23. A device as claimed in any of claims 12 to 22, in which a second chamber is defined between the first and second parts in which the electric circuitry is located.

24. A device as claimed in claim 23, in which the second chamber is not in communication with the said chamber.

25. A device as claimed in any preceding claim, in which the signal means is locatable to be readily visible by a user of the device.

26. A device as claimed in any preceding claim, in which the signal means gives one or both of audio and visual pressure related signals when activated by the transmitter.

27. A device as claimed in any preceding claim, in which the device comprises attachment formation to enable attachment of further apparatus to the device.

28. A device as claimed in claim 27, in which the attachment formation comprises a valve which remains closed until further apparatus is attached to the attachment formation.

29. A device as claimed in any preceding claim, in which the device is so formed so as not to significantly interfere with the normal operation of any further apparatus attached thereto, with the pressure source.

30. A device as claimed in any preceding claim, in which the device enables pressure to be supplied therethrough to the pressure source, for example to pressurize the source.

31. A device as claimed in any preceding claim, in which the device is connectable to a valve of an inflatable body, such as a tyre.

32. A device as claimed in claim 31, in which the device comprises a pressure release formation to release the valve of the inflatable body to provide communication between the pressure inside the body and the chamber.

33. A device as claimed in claim 31 or claim 32, in which the device comprises a portion permitting connection of the device to the valve.

34. A device as claimed in claim 32 or claim 33, in which the release formation comprises a projection extending from the entrance to the chamber toward the connecting portion to be contactable with a part of the valve to open the valve and release pressure from the pressure source into the chamber as the device is connected to the valve.

35. A device as claimed in any of claims 31 to 34, in which the device is so constructed to enable the device to remain on the valve of a rotating wheel without significantly adversely affecting the balance of the wheel.

36. A device substantially as hereinbefore described with reference to the accompanying drawings.

37. Any novel subject matter or combination including novel subject matter disclosed, whether or not within the scope of or relating to the same invention as any of the preceding claims.