GB2318456A

GB2318456A - Switch

Info

Publication number: GB2318456A
Application number: GB9725829A
Authority: GB
Inventors: David William Jones; Paul Reynolds
Original assignee: Craig and Derricott Ltd
Current assignee: Craig and Derricott Ltd
Priority date: 1997-12-06
Filing date: 1997-12-06
Publication date: 1998-04-22
Anticipated expiration: 2017-12-06
Also published as: GB2318456B; GB9725829D0

Abstract

A switch (10) comprises a body (12), a movable member (13) mounted in the body (12) and being moveable by an operating member (17) to open or close the switch (10), locking means (23, 24) to prevent the movable member (13) being moved back to the closed or opened condition once moved by the operating member (17) to the open or closed condition and a releasing means (35) release the locking means (23,24) comprising an element which is cooperable with the locking means (23,24) to free the movable member (13) thus to permit the movable member (13) to be moved back to the closed or opened condition.

Description

Description of Invention This invention relates to a switch.

It is a requirement in for example a driver's cab of a train or tram, or elsewhere on the train or cab, for isolating switches to be provided so that particularly in the event of a malfunction of an item of equipment, the equipment may be electrically isolated.

For certain such switches, for safety reasons it is a requirement that once switched electrically to isolate the equipment, the equipment remains electrically isolated until, for example, the equipment is inspected by an engineer.

Switches are thus known which may be operated electrically to isolate an item of equipment, and when thus operated, cannot be operated to restore the electrical supply without the intervention of an engineer. Generally these comprise panel mounted switches which are operable from one side of the panel, but having a reset means provided, access to which can only be obtained from an opposite side of the panel, requiring the mounting panel or the like to be at least partially disassembled in order to obtain access to the reset means.

This is obviously inconvenient.

According to one aspect of the invention we provide a switch comprising a body, a movable member mounted in the body and being moveable by an operating member to open or close the switch, locking means to prevent the movable member being moved back to the closed or opened condition once moved by the operating member to the open or closed condition, characterised in that a releasing means is provided to release the locking means, the releasing means comprising a element which is removeably engageable with the locking means to free the movable member thus to permit the movable member to be moved back to the closed or opened condition.

Thus with a switch in accordance with the invention rather than the switch having an integral reset means which has to be made relatively inaccessible e.g. behind a panel in which the switch may be mounted, the releasing means is separate from the remainder of the switch and may be used to release the switch without requiring a mounting panel or the like to be at least partially disassembled.

Thus the operating member may be operable from one side of the panel and the releasing means may too be engageable with the locking means from the same one side of the panel.

Preferably the switch is of the kind in which the movable member is rotatable about an operating axis to change the operating condition of the switch. The removeable element of the releasing means may be engageable with the locking means by a movement in a direction parallel with the operational axis of the movable member and may for example comprise a particular configuration pin.

The operating member may comprise a removable key which may be usable to operate a plurality of switches. The key may be a so-called driver's key where canied by a driver or guard of a train or tram.

The locking means may comprise at least one locking element mounted within the movable member and being spring biased outwardly, the body comprising a recess for the locking element into which a part of the locking element is received when the movable member is moved by the operating member to the open or closed condition to prevent the movable member being further moved.

For example, the movable member may be movable rotationally by the operating member and the locking element may be spring biased radially outwardly, the removable element being engageable with the locking element so as to move the part of the locking element against the spring bias back into the movable member, so as to permit the movable member again to be rotated by the operating member. Of course in practice a plurality of locking elements may be provided, all of which have to be moved by the removable element of a particular configuration, to move parts of them back into the movable member to release the movable member, the number of locking elements provided and their configuration depending on the degree of security required.

The body may comprise an end wall having a first opening adapted to receive the operating member therethrough so that the operating member may operate the movable member, and a second opening adapted to receive the removable element to permit the removable element to engage with the locking means.

The invention is particularly applicable where the switch is adapted to control an operating function of a vehicle such as a train or a tram.

According to a second aspect of the invention we provide a vehicle having a switch according to the first aspect of the invention.

The invention will now be described with reference to the accompanying drawings in which FIGURE 1 is an illustrative perspective view of a switch in accordance with the invention; FIGURE 2 is an exploded part cross-sectional view through the switch of Figure 1; FIGURE 3 is a view of the switch of figure 2 shown assembled, but showing the switch with the moveable member in a locked condition; FIGURE 4 is a view similar to figure 3 but showing a removable releasing means releasing the switch.

Referring to the drawings, a switch 10 which is adapted to be mounted in a panel 11 comprises a body 12 within which there is mounted for rotation about an operating axis A a moveable member 13. The moveable member 13 has one end 14, a special configuration for a purpose hereinafter explained, and at an opposite end, a part P which is adapted to locate in or carry an electrical connection which, as the moveable member 13 is rotated, opens or closes an electrical current.

The end 14 is of a special configuration to correspond with a special configuration 16 provided on an operating member 17 comprising a drivers key.

The key 17 is removable from the body 12 and may be used to operate for example, a plurality of switches within a driver's cab or elsewhere on a vehicle such as a train or tram.

Within a central region 15 of the moveable member 13 there are provided a pair of passages 21 and 22 in each of which there is provided carries a respective locking element 23, 24. The locking elements 23, 24 are spring biased radially outwardly of the operating axis A by springs S held by spring caps 24, but when the switch 10 is in its normal operating condition the locking elements 23, 24 are retained within their respective passages 21, 22 by an inside wall 25 within the body 12 of the switch 10 as shown in Figure 2..

However, when the moveable member 13 is rotated by the key 17 from the position shown in Figure 2 to the position shown in Figure 3, the passages 21 and 22 of the moveable member 13 become aligned with respective recesses 30, 3 1 of the body 12, and thus at least the nose parts of the locking elements 23, 24 are moved by the springs S into the aligned recesses 30, 31, as shown in figure 3.

Thus the key 17 may rotate the moveable member 13 about the operating axis A to open or close the switch 10 from the normal operating condition shown in Figure 2, to the condition shown in Figure 3, when further rotation of the moveable member 13 will be prevented by virtue of the nose parts of the locking elements 23, 24 being received in the recesses 30, 31 of the body 12.

The key 17 may be disengaged with the body 12 when the moveable member 13 is in the condition shown in Figure 3 or may be retained therein as desired.

The switch 10 may thus be used electrically to isolate an item of equipment, but when that equipment is thus electrically isolated by the moveable member 13 being moved to the Figure 3 condition, it is not possible to rotate the moveable member 13 to restore electrical continuity because the moveable member 13 is locked in the Figure 3 condition.

In accordance with the invention, there is provided a releasing means being in this example, a pin-key like element 35. The element 35 may be received within an opening 36 in an end wall 37 of the body 12 in a direction generally parallel with the operating axis A of the moveable member 13. The opening 36 opens internally of the body 12, to a passage 38 which is crossdrilled with the recesses 30, 31 in which the nose parts of the locking elements 23, 24 are located. Within the recesses 30, 3 1 there are provided moveable actuating elements 40, and 41a, 41b respectively. The pin element 35 is of a stepped configuration, and as it is inserted into passageway 38, a smallest diameter end part 45 co-operates with the actuating elements 41 a, in the recess 31 which engages actuating element 41b to move the nose part of the locking element 24 against the force of its resilient biasing spring, back into the passage 22 of the moveable member 13. The next stepped region 46 of the releasing element 35 co-operates with the actuating element 40 in recess 31 to move the nose part of the locking element 23 back into its passage 21 within the central region 15 of the moveable member 13.

The pin releasing element 35 is configured so that the amount of movement of the actuating elements 40 and 41a, 41b is exactly enough to move the locking elements 23, 24 sufficiently to release the moveable member 13 for movement again about the operating axis A. Thus when the releasing pin element 35 is received in the body 12 in the manner described, the locking means is released.

It is envisaged that a suitable releasing element 35 would be carried securely by an engineer or supervisor only so that the electrical supply cannot be restored to equipment by a driver or guard of a train or tram for example, having a key 17 without an engineer or his supelvisor having inspected that equipment and made any necessary repairs. The invention facilitates the restoration of the electrical supply when any necessary repairs have been effected without an engineer having to at least partially dismantle the panel 12 in which the switch 10 is mounted.

Various modifications may be made without departing from the scope of the invention.

For example in the arrangement described with reference to the drawings, the pin releasing element 35 has only two stepped parts 45, 46 corresponding to the two locking elements 23, 24 carried by the moveable member 13. If desired where a greater degree of security is required, more than two locking elements may be provided, or in another arrangement where a lesser degree of security is required, a single locking element only may be provided with the pin or other element for releasing the loading means being suitably correspondingly configured.

Although as described the key 17 which operates the moveable member 13 is removable from the body 12 in another arrangement this may not be so.

In the arrangement described, the releasing element 35 and operating key 17 are both operated at one side of the panel 12 in which the switch 10 is mounted, but the releasing element 35 need not be moveable exactly in a parallel direction to the operating axis A, in another example.

The switch 10 may be used either to provide electrical continuity when it is in its normal operating condition and for the electrical equipment thus supplied to be electrically isolated when the moveable member 13 is moved to the position shown in Figure 3 but in another arrangement, where the switch 10 is to be used to apply a safety measure for example, the normal operating condition of the switch 10 may be that equipment is electrically isolated when the switch 10 is in its normal operating condition, and electrical continuity is provided when the moveable member 13 is moved to the operating condition shown in Figure 3.

Although as described, the moveable member 13 is rotatable about an operating axis A, in another example, the moveable member 13 may be moveable in another sense.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in tennis of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

1. A switch comprising a body, a movable member mounted in the body and being moveable by an operating member to open or close the switch, locking means to prevent the movable member being moved back to the closed or opened condition once moved by the operating member to the open or closed condition , characterised in that a releasing means is provided to release the locking means, the releasing means comprising an element which is cooperable with the locking means to free the movable member thus to permit the movable member to be moved back to the closed or opened condition.

2. A switch according to claim 1 wherein the switch is adapted to be panel mounted, the operating member being operable from one side of the panel and the releasing means being engageable with the locking means from the same one side of the panel.

3. A switch according to claim 1 or claim 2 wherein the movable member is rotatable about an operating axis to change the operating condition of the switch.

4. A switch according to claim3 wherein the removeable element of the releasing means is engageable with the locking means by a movement in a direction parallel with the operational axis of the movable member.

5. A switch according to anyone of the preceding claims wherein the removable element is a pin.

6. A switch according to any one of the preceding claims wherein the operating member comprises a removable key.

7. A switch according to any one of the preceding claims wherein the locking means comprises at least one locking element mounted within the movable member and being spring biased outwardly, the body comprising a recess for the locking element into which at least part of the locking element is received when the movable member is moved by the operating member to the open or closed condition to prevent the movable member being further moved.

8. A switch according to claim 7 wherein the movable member is movable rotationally by the operating member and the locking element is spring biased radially outwardly, the removable element being engageable with the locking element so as to move the part of the locking element against the spring bias back into the movable member, so as to permit the movable member again to be rotated by the operating member.

9. A switch according to any one of the preceding claims wherein the body comprises a end wall having a first opening adapted to receive the operating member therethrough so that the operating member may operate the movable member, and the end wall having a second opening adapted to receive the removable element to permit the removable element to engage with the locking means.

10. A switch according to any one of the preceding claims adapted to control an operating function of a vehicle.

11. A switch according to claim 9 wherein the vehicle is a train or a tram.

12. A switch substantially as hereinbefore described with reference to the accompanying drawings.

13. A vehicle having a switch according to any one of the preceding claims.

14. Any novel feature or novel combination of features described herein and/or shown in the accompanying drawings.