GB2317650A

GB2317650A - A control device

Info

Publication number: GB2317650A
Application number: GB9620132A
Authority: GB
Inventors: Laurence Marsh
Original assignee: BOLTON SCHOOL
Current assignee: BOLTON SCHOOL
Priority date: 1996-09-27
Filing date: 1996-09-27
Publication date: 1998-04-01
Also published as: GB9620132D0

Abstract

A pneumatic control system is provided which comprises a control device having a fluid inlet 10, a fluid outlet 12 and a slot 14 for insertion of a card 18 therein. The control device is only operable when the correct card 18 is inserted into the slot 14, thereby modifying the fluid flow characteristics between the inlet and outlet in a predetermined manner. Accordingly the pneumatic control system can be used as a locking mechanism in numerous environments, especially where it is inconvenient or unsafe to use electrical switching.

Description

A CONTROL DEVICE This invention relates to a control device for a fluid control system.

Pneumatic control systems are widely used for controlling operation of mechanisms and provide an alternative to electric control systems.

Pneumatic control can be advantageous, especially in the case where it is inconvenient or unsafe to use electrical switching.

There is however, the problem of providing secure or coded operation in a convenient manner.

An object of the present invention is to provide a control device for a fluid control system which can be provided with a secure or coded means of operation in a convenient manner.

According to the present invention there is provided a control device for a fluid flow control system, said device comprising at least one fluid inlet, at least one fluid outlet and a key adapted to be inserted into said control device between the inlet and outlet into predetermined relationship therewith so as to modify the fluid flow characteristics between the inlet and outlet in dependence on correspondence between combinations of fluid flow elements respectively of the key and of the control device.

With this arrangement, the control device will only operate to modify the fluid flow characteristics between the inlet and outlet, when a key having a combination matching that of said control device is inserted. In a particularly convenient manner a fluid control system can be operated in a secure or coded manner.

The arrangement may be such that the key acts to permit fluid flow.

Alternatively, fluid flow may be stopped, or its magnitude may be caused to vary by the key.

Most preferably the control device will be pneumatic although other liquid or gaseous systems may also be used.

In a preferred embodiment the control device may have a key receiving body with two matrix sections which define therebetween a key-receiving aperture.

The fluid flow elements of the key may be through holes or passages which are brought into alignment with corresponding ports of the control device associated with the inlet and outlet.

The key may also have a configuration thereon which is required to match a corresponding cooperable configuration of the device on insertion of the key.

This may comprise one or more receiving portions, such as slits, on the key engageable with one or more projections, such as pins, on the control device.

The key may take any suitable form but preferably is of the nature of a card, i.e. a rectangular or any other suitably shaped rigid or semi-rigid plate. The above mentioned key-receiving aperture may comprise a generally flat slot to receive a card-shaped key.

The said fluid flow elements may be arranged to control fluid flow between a single said inlet and a single said outlet via the key. Alternatively, there may be multiple inlets and/or outlets whereby fluid flow is controlled simultaneously through multiple routes, or selectively through one or more of a large number of possible routes depending on the key selected for insertion and/or the mode of insertion of the key selected from multiple possible modes.

The key may act to implement different kinds of fluid flow control at the same time. Thus, for example, in addition to permitting fluid flow between input and output ports, it may also block fluid escape through supplementary escape ports. This can give enhanced security insofar as it is necessary to block fluid escape for proper operation as well as directing permitted fluid flow.

In a particularly preferred embodiment, a valve is provided which is operated by engagement with the key when this is fully inserted. This gives additional security in that the key has to be capable of correctly engaging the valve as well as having the correct fluid flow elements. The valve may be a spring-biased plunger operated valve or any other suitable device.

This valve may be associated with the said outlet to give a desired control output when both the valve and the outlet are correctly actuated. Thus, there may be a main outlet valve which is operated in response to fluid received from the said outlet and from the first said valve.

The said main outlet valve may be a pilot operated valve whereby fluid from the said outlet controls operation of the main outlet valve to permit fluid flow therethrough from the first said valve.

The said fluid output from the pilot operated valve may be directed to a pneumatic cylinder.

There may be multiple pilot operated valves associated with multiple outlets of the control device.

The above mentioned matrix sections may be connected to each other by means of a hinge arrangement which may be fastened together by a hook and clasp.

Over-centre clamps or any other suitable arrangements may also be used.

In a preferred embodiment a fluid reservoir is connected to the said inlet.

Provision may be made for connection of a gas cylinder to give an emergency supply of pressurised fluid.

The control device of the invention may be used for any suitable purpose.

In one embodiment, a pivot joint (king pin) between a traction unit and trailer of a motor vehicle is security locked by a mechanism which can only be released on use of a card-operated control device as described above.

Thus, and in accordance with a second aspect of the present invention there is provided a lockable pivot joint for a trailed vehicle characterised in that the lock is released by insertion of a key between fluid flow inlet an outlet connection. The inlet and outlet connection and the key may be provided by a control device as described above.

The invention will now be described further, by way of example only, and with reference to the accompanying drawings in which: Fig. 1 illustrates a perspective view of one form of a single function control device according to the invention; Fig.2 illustrates a perspective view of an opened out card-receiving body of a modification of the device of Fig. 1; Fig. 3 illustrates a perspective view of the modified device of Fig. 2; Fig. 4 is a cross-sectional view of a modified version of a receiving matrix section of the control device of Fig. 1; Fig. 5 is a perspective view of an arrangement of tubes and gas containers for use with the embodiments of Figs. 1 - 4; Fig. 6 is a perspective view of an '0' ring seal arrangement as used with the embodiment of Figs. 1 - 4;'and Fig. 7a and 7b are perspective views of a modified version of part of the control device of the embodiments of Figs. 1 - 4.

The control device illustrated in Fig. 1 comprises within a housing (not shown) a card-receiving body, a plunger operated pneumatic valve 2, and a pilot operated pressure valve 4 connected to a pneumatic operating cylinder (not shown).

The card receiving body comprises two rectangularly shaped blocks, or matrix sections 6, 8, which are clamped in face-to-face contact by fixing screws which are passed through the blocks at their corners. The confronting faces of the matrix sections 6, 8 are provided with openings, recesses and grooves yet to be described. One section is an inlet matrix section 6 and has therein a main inlet channel 10 leading to an outlet of the valve 2, and an outlet channel 12 leading to a pilot inlet of the pressure valve 4.

The two matrix sections 6, 8 are provided with rectangular recesses which together define a rectangular slot 14 which terminates at one end with an inner abutment wall 16 and which is open at its opposite end at one side of the assembled card-receiving body. A card 18 is provided which is insertable through the open end of the slot 14 so as to fit snugly within the slot 14 with a forward end of the card 18 against the abutment wall 16 and the rear end of the card 18 projecting freely out of the open end of the slot 14. Near to the abutment wall 16, there are two upstanding pins 20 projecting perpendicularly from the recess face 22, of the inlet matrix section 6.

These pins 20 cooperate with correspondingly positioned slits 23 in the forward end region of the card.

The plunger operated valve 2 is mounted in relation to the blocks so that a spring loaded operating plunger 24 of the valve 2 passes through a passageway 26 which is defined by confronting grooves of the matrix sections 6, 8 and which extends from one side of the card-receiving-body into the card-receiving slot 14 so as to terminate in the centre of the abutment wall 16. The plunger 24 passes through this passageway and has a head which is normally located in front of the abutment wall 16. The forward end of the card 18 bears against this head when it is pushed into the slot 14. The valve 2 is connected to a source of compressed air through an inlet 28, and is normally spring biased to a closed position. The outlet 30 of the valve 2 is also connected to a main inlet 32 of the pilot operated valve 4.

The inlet matrix section 6, has therein two air distribution channels 1 7 connecting with the above mentioned inlet and outlet channels. These channels 17 comprise bores or grooves connected by rubber tubing. The receiving matrix section 8 has an internal air distribution channel 34 this also comprising a bore or groove with rubber tubing exiting at the output port or channel.

The respective distribution channels 17, 34 terminate at two openings 36, 38 within the recesses of the two matrix sections 6, 8. The openings 36 in one recess are equal in number to, and are respectively aligned with the openings 38 in the other recess. The card also has an equal number and distribution of holes 40 therein.

Operation of the control device is achieved by inserting the card 18 fully into the slot 14. The two slits 23 receive the two pins 20 and allow the leading edge of the card 18 to contact the abutment wall 16 of the slot 14, and the spring loaded plunger 24 of the plunger operated valve 2 is fully depressed by the card 18. This causes the valve to open to allow compressed air to flow to the inlet channel and through the connected distribution channel 17 to the respective opening in the recess of the inlet matrix section 6.

From there, the air flows through the aligned holes 40 in the card 18 and the recesses of the matrix sections 6, 8, via the internal distribution channel 34 in the receiving matrix section 8 to the outlet channel in the inlet matrix section 6 and hence to the pilot inlet of the valve 4.

Admission of compressed air to the pilot inlet of the valve 4 causes the valve to open to allow compressed air at its main inlet to flow through the valve to the main operating pneumatic cylinder (not shown). This provides a pneumatic or mechanical output as required.

Operation of the main pneumatic cylinder is therefore controlled by means of the card 18 which, for correct operation is required to have the correct positioning of the slits and the holes 40.

If an incorrectly 'coded' card 18 is used air will not be able to flow to the pilot inlet of the pilot operated pressure value 4. It will be understood that the - pins 20 and corresponding slits 23 can be located at different positions along the card edge (say any two of ten possibilities) and the holes 40 can also be located at a range of different positions. To avoid easy determination of the 'code' by visual inspection, there may be additional dummy holes 40 and/or slits 23 in the card 18 at position where they perform no useful function.

Fig. 2 shows a four way modification of the control device of Fig. 1, and the same reference numerals are used for the same component parts.

The arrangement of Fig. 2 differs from that of Fig. 1 in that the inlet channel of the inlet matrix section 6 is connected by distribution channels 17 to four main openings 36 and one additional large supplementary opening 42 in the recess of such sections. There are also four aligned openings 38 in the recess of the other matrix section 8 which are connected by respective distribution channels 34 to respective outlets. The receiving matrix section 8 also has a large through port aligned with the supplementary opening 42 of the inlet matrix section 6. This could be termed an anti-tamper port and could be used to trigger an alarm system in any attempt at unauthorised usage.

The card 44 used with the control device of Figs. 2 and 3 differs from that of Fig. 1 in that each end region has a respective different arrangement of two slits 23.

The card 44 can be inserted into the card-receiving slot 14 in any of four different dispositions i.e. either end first and either face towards the inlet matrix section 6.

In each disposition a respective one of the holes 40 in the card 44 is aligned between a respective pair of aligned matrix holes 36, 38 thereby allowing compressed air to flow from the switched-on plunger operated valve 2 through a respective one of the outlet channels.

Each outlet is connected to a pilot inlet of a respective pilot operated pressure switch 4 of the kind shown in Fig. 1. Main inlets of these switches are connected via a manifold 46 to the outlet of the plunger-operated valve 4.

The pilot operated valves 4 have outlets connected to respective pneumatic operating cylinders in like manner to Fig. 1.

In this way four different pneumatic cylinders can be controlled selectively with the same card 44, by selection of the disposition of insertion of the card 44.

The above described large opening 42 and port are provided in order to hamper unauthorised operation of the control device by insertion of a structure which simply depresses the plunger 24. For correct operation it is also necessary to have a card 44which blocks air flow from the large opening to the part whilst permitting air flow between the selected pair of aligned matrix openings 36, 38.

If this is not done, the large opening and port will give rise to a pressure reduction in any air reaching the outlets so that there is insufficient pressure to operate any of the pilot operated valves 4.

The single function control device of Fig. 1 can be altered in order to give a greater number of possible combinations, by altering the receiving matrix section 8 of the control device, as shown in Fig. 4.

Instead of having two holes 38 linked by a single distribution channel 34, the altered receiving matrix section 48 has a two-dimensional array of multiple (five by five) holes 38 on the recess face 50 at the ends of channels 52 which extend through the receiving matrix section 48. These channels 52 are then joined together at the back of the section by linking galleries 54 beneath a sealing back plate (not shown).

The holes 38, channels 52 and galleries 54 are formed with a very accurate machining tool, such as a CNC machine. One of the twenty five holes 38 in the matrix section is aligned with the inlet hole 36 on the inlet matrix section 6 and a second one of the twenty five holes is aligned with the outlet hole 36 on the inlet matrix section 6, these holes being two such holes which are linked by galleries 54.

In order to activate the control device it is necessary to have the correct card 18 with the correctly positioned holes 40 corresponding to the position of the above mentioned two selected holes 36, 38 of the five by five array. If an incorrect card 18 is inserted into the control device, even if the card 18 is capable of receiving the above described pins 20, it is unlikely that the card 18 will contain two holes 40 in exactly the right position to permit air flow from the inlet channel to the outlet channel.

As shown in Fig. 5, with all of the above described embodiments the inlet to the plunger operated valve 2 may be connected via a T-piece 56, to a main source of compressed air and to a reservoir 58.

The connection to the main source of compressed air is effective via a nonreturn valve 60.

The reservoir is compressed by the main source and ensures a steady flow of air to the control device in use. The reservoir 58 can be topped up through a gas cylinder connection 62 via a non return valve 64. Carbon Dioxide cylinders or any other gas cylinders may be attached to the gas cylinder connection 62, as appropriate. The use of a gas cylinder 66 permits emergency operation if there is a failure in the main supply, or if the main supply is switched off.

In all the above described embodiments, the port holes 36, 38 positioned on the recess faces 22 are all bounded by O-ring seals 68 as shown in Fig. 6. These O-ring seals 68 are connected to the ends of the tubes or channels 17, 34 and prevent air loss at the junction with the card when the card 18, 44 is inserted into the slot 14.

Instead of fixing screws, the two matrix sections 6, 8 of the control device described in all the above described embodiments may be connected together by two hinges 70 which are positioned at the opposite end of the control device in respect to the open end of the card-receiving slot 14. This is illustrated in Figs. 7a and 7b.

As shown in Fig. 7a a clasp 72 may be provided for holding the hinged sections together. The control device can also have its matrix sections 6,8 held together by over centre clamps 74 as shown in Fig. 7b. These over centre clamps 74 have a bar running perpendicular to the recess face 50 of the control device.

This bar passes through the receiving matrix section 8 and is affixed to the inlet receiving section 6. There is a lever 76 connected to the part of the bar which is not within the matrix sections 6, 8, so that as the lever 76 is rotated the bar is pulled toward the lever 76. In doing so, the bar pulls both matrix sections 6, 8 of the control device together. The reason for using either the clasp 72 or the over centre clamps 74, is to ensure that the matrix sections 6, 8 are as close together as possible, thereby ensuring that the seals between the port holes 36, 38 and holes 40 within the smart card 18, 44 are extremely tight. This system could be used to ensure that the key card is securely locked in position until removal is required.

With the above described embodiments the control device provides a pneumatic system which is controlled by the insertion of a specific 'key' card.

The control device may be used for controlling any suitable mechanism or - system. In one example embodiment, a pivot joint (king pin) between a traction unit and trailer of a motor vehicle is security locked by a mechanism which can only be released on use of a card-operated control device as described above. The "spring brake " system on the trailer unit can be similarly immobilised thus rendering the trailer wheels "locked" and therefore in a state where it is unable to be towed away.

The invention is not limited to the above described embodiments and many variations and modifications are possible.

Claims

1. A control device for a fluid flow control system, said device comprising at least one fluid inlet, at least one fluid outlet and a key adapted to be inserted into said control device between the inlet and outlet into predetermined relationship therewith so as to modify the fluid flow characteristics between the inlet and outlet in dependence on correspondence between combinations of fluid flow elements respectively of the key and of the control device.

2. A control device as claimed in claim 1, such that the key acts to permit fluid flow.

3. A control device as claimed in claim 2, wherein fluid flow may be stopped, or its magnitude may be caused to vary by the key.

4. A control device as claimed in claim 3, wherein the control device is pneumatic.

5. A control device as claimed in claim 4, wherein the control device may have a key receiving body with two matrix sections which define there between a keyreceiving aperture.

6. A control device as claimed in claim 5, wherein the fluid flow elements of the key may be through holes or passages which are brought into alignment with corresponding ports of the control device associated with the inlet and outlet.

7. A control device as claimed in claim 6, wherein the key has a configuration thereon which is required to match a corresponding cooperable configuration of the device on insertion of the key such as one or more receiving portions on the key, engageable with one or more projections on the control device.

8. A control device as claimed in claim 7, wherein the configuration of the key may comprise one or more receiving portions, engageable with one or more projections in the control device.

9. A control device as claimed in claim 8, wherein the key is of the nature of a card and the key receiving aperture comprises a generally flat slot to receive a card-shaped key.

10. A control device as claimed in claim 9, wherein said fluid flow elements may be arranged to control fluid flow between a single said inlet and a single said outlet via the key.

11. A control device as claimed in claim 9, wherein there are multiple inlets and/or outlets whereby fluid flow is controlled simultaneously through multiple routes, or selectively through one or more of a large number of possible routes depending on the key selected for insertion and/or the mode of insertion of the key selected from multiple possible modes.

12. A control device as claimed in any preceding claim, wherein the key may act to implement different kinds of fluid flow control at the same time so that in addition to permitting fluid flow between input and output ports, it also blocks fluid escape through supplementary escape ports, which thereby provides enhanced security insofar as it is necessary to block fluid escape for proper operation as well as directing permitted flow.

1 3. A control device as claimed in claim 12, wherein a spring biased plunger operated valve is provided which is operated by engagement with the key when this is fully inserted, thereby providing additional security in that the key has to be capable of correctly engaging the valve as well as having the correct fluid flow elements.

14. A control device as claimed in claim 13, wherein said spring biased plunger operated valve is associated with the said outlet to give a desired control output when both the valve and the outlet are correctly actuated.

15. A control device as claimed in claim 14, wherein there is provided a main outlet valve which is operated in response to fluid received from the said outlet and the said spring biased plunger operated valve.

16. A control device as claimed in claim 15, wherein the main outlet valve is a pilot operated valve whereby fluid from the said outlet controls operation of the main outlet valve to permit fluid flow therethrough from the said first valve.

1 7. A control device as claimed in claim 16, wherein the said fluid output from the pilot operated valve may be directed to a pneumatic cylinder.

18. A control device as claimed in claim 17, wherein there are multiple operated pilot valves associated with multiple outlets of the control device.

19. A control device as claimed in claim 18, wherein the matrix sections are connected to each other by means of a hinge arrangement which are fastened together by a hook and clasp.

20. A control device as claimed in claim 18, wherein the matrix sections are connected to each other by means of over centre clamps.

21. A control device according to any preceding claim, wherein a fluid reservoir is connected to the said inlet.

22. A control device as claimed in claim 21, wherein a pivot joint between a traction unit and trailer of a motor vehicle is security locked by a mechanism which can only be released on use of said card-operated control device.

23. A control device as claimed in claim 22, wherein there is provided a lockable pivot joint for a trailed vehicle, said lock being released by insertion of a key between fluid flow inlet and outlet connection, said inlet and outlet connection and the key being provided by the control device.

24. A control device substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.