GB2538035A

GB2538035A - Fire-retardant connection system

Info

Publication number: GB2538035A
Application number: GB1419609.1A
Authority: GB
Inventors: Elam John
Original assignee: FIALINE Ltd
Current assignee: FIALINE Ltd
Priority date: 2014-11-04
Filing date: 2014-11-04
Publication date: 2016-11-09
Also published as: GB201419609D0

Abstract

A fire retardant electrical connection system comprising a first type connector 20 and a second type connector (30, figure 7) for connecting together, where the connectors each comprise: an outer sheath 202, an inner connection part 204, and electrical terminals 208. The connectors are arranged for engagement such that when connected they form a heat resistant shield around the terminal. Preferably the connectors are male and female, where the female connectors outer sheath may comprise axial keyways 214 in the form of elongate slots for receiving correspondingly shaped keys (314) of the male connector. The keyways may end in a circumferential groove that has a latch portion in the form of an integrally moulded, resilient pawl 218 for making a latching engagement with the key of the male connector. A method of making the fire-retardant electrical connection between two connectors is included. These electrical connections may be used for cables of life safety systems such as; fire alarms, voice alarms, public address systems, and emergency lighting systems.

Description

Fire-Retardant Connection System The present invention relates to a fire retardant electrical connection system, and to a method of making a 5 fire-retardant electrical connection.

Modular connectivity systems, in which electrical cables can be connected together or to devices, either on or off site, using pre-configured connectors that are designed to 10 fit together, are well known in the prior art.

However, electrical connections for cables of life safety systems, such as fire alarm, voice alarm/public address systems and emergency lighting systems, are typically made in a bespoke manner by a skilled installation engineer. The engineer must strip back any insulation from cables to be connected to each other, or to devices, before making a good electrical and physical connection. He must then apply suitable thermal protection so that the connection can meet rigorous safety standards. All of this can take considerable time, and the quality of the connection will depend upon how well the installation engineer has performed his task.

Embodiments of the present invention aim to provide a modular fire-retardant electrical connection system, and a method of making a fire-retardant electrical connection using such a system.

The present invention is defined im the attached independent claims, to which reference should now be made.

Further, preferred features may be found in the sub-claims appended thereto.

According to one aspect of the present invention, there is 5 provided a fire-retardant electrical connection system comprising at least one connector of a first type and at least one connector of a second type for connecting together, wherein the connectors each comprise an outer sheath, an inner connection part, and one or more 10 electrical terminals, and wherein the connectors arc arranged in use for engagement such that when connected they form a heat-resistant shield around the terminals.

The or each connector of the first type may comprise a male 15 connector, and the or each of connector of the second type may comprise a female connector.

Preferably the connectors are arranged in use for engagement such that the sheath of one connector becomes 20 located within the sheath of the other connector.

Preferably the sheath of Lhe male connector becomes located within the sheath of the female connector. In a preferred arrangement the connectors are arranged in use for slideable engagement. Preferably the sheath of the male connector slides within the sheath of the female connector.

The connectors may comprise a proximal, or cable end and a distal, or open end. The cable end may be arranged in use 30 to be connected to one or more cables or wires, preferably by crimping.

The inner connection parts may comprise the terminals for making an electrical connection.

The inner connection parts of the male and/or female 5 connector are preferably axially spaced from the open end of the outer sheath.

Preferably the connectors, or least the outer sheaths, are manufactured from a material that complies with the 10 requirements of BS 7629-1 for standard and enhanced grade fire retardant cables.

Preferably the connection parts are arranged such that when the male and female connectors are engaged in use an 15 electrical connection is made between at least one, and preferably more than one, terminal of each connector.

in a preferred arrangement the connectors are arranged to become physically locked together. The connectors may be arranged in use to become locked together by engagement of a first latch portion on one of the connectors and a second latch portion on the other of the connectors.

The latch portions may be arranged for releasable engagement with each other. In a preferred arrangement the first latch portion comprises a tooth portion and the second latch portion comprises a pawl portion. Preferably the pawl portion is resiliently biased in a locked configuration. The pawl portion may be arranged in use to become temporarily displaced to a second, unlocked configuration by movement in the Loath in one direction.

In a particularly preferred arrangement the latch is moveable between an unlocked configuration and a locked configuration by relative movement between the connectors, and more preferably by relative rotational movement between the connectors.

The connectors may connect electrically by relative axial movement and/or may lock physically by relative rotational movement.

One of the connectors preferably comprises at least one key and the other of the connectors preferably comprises at least one keyway, such that during engagement of the connectors the or each key engages with a respective keyway for relative axial and/or relative rotational movement of the connectors.

The invention also includes a method of making a fire-retardant electrical connection between connectors, each connector comprising an outer sheath, an inner connection part and at least one electrical terminal, wherein the method comprises engaging the connectors such that when connected they form a heat-resistant shield around the terminals.

Preferably, when the connectors are engaged the sheath of one connector becomes located within the sheath of the other connector.

The method may comprise physically locking together the connectors by engagement of a first latch portion on one of the connectors and a second latch portion on the other of the connectors.

In a preferred arrangement the method comprises connecting 5 the connectors electrically by relative axial movement and locking them physically by relative rotational movement.

The or each connector may comprise a moulding, and more preferably an injection moulding.

The invention also includes a connector for use in a connection system according to any statement herein.

The invention also includes a cable attached to a connector 15 for use in a connection system according to any statement herein.

The invention may include any combination of the features or limitations referred to herein, except such a 20 combination of features as are mutually exclusive, or mutually inconsistent.

A preferred embodiment of the present invention will now be described, by way of example only, with reference to the 25 accompanying diagrammatic drawings, in which: Figure 1 shows in side view, an electrical connection system according to an embodiment of the invention, comprising male and female connectors in a connected 30 configuration; Figure 2 shows the connection system of Figure 1 in a perspective view; Figure 3 shows in perspective view a female connector of 5 the system of Figure 1; Figure 4 is a sectional view of the female connector of Figure 3; Figure 5 is a more detailed sectional view of the female connector; Figure 6 is a rear end view of the female connector; Figure 7 is a perspective view of a male connector of the system of Figures 1 and 2; Figure 8 is a sectional view of the male connector of Figure 7; Figure 9 is a cross section of the connector of Figure 7, taken along line 9-9' of Figure 7; Figure 10 is a front end view of the male connector; Figure 11 is a rear end view of the male connector; Figure 12 is a sectional view of the male and female connectors connected together.; and Figure 13 is a cross sectional view of the connectors in a connected configuration.

Turning to Figures 1 and 2, there is shown generally at 10 a pair of fire-retardant electrical connectors 20 and 30, in a connected configuration. The connectors 20 and 30 are 5 generally cylindrical and formed of fire-retardant materials such as cable compounds that comply with BS 76291 for standard and enhanced grades of cables. The connectors are arranged in use for connecting cables (not shown) to form a physical and electrical connection for use 10 in modular wiring systems that are able to withstand high temperatures associated with the requirements of life safety systems.

Figures 3 to 6 show the female connector 20 in detail. The connector 20 comprises a cylindrical outer sheath 202, an inner connection part 204 and a threaded, cable-end portion 206, for attachment to a cable (not shown). The inner connection parL 204 comprises a hollow cylinder and has three elongate, arcuate electrical terminals 208 embedded therein at radially spaced locations for engagement with corresponding terminals on the male connector 30, as will be described later. The terminals 208 begin within the threaded end portion 206 and extend axially through a bulkhead 210 and stop short of a distal end of the inner connection part 204 where contact portions 208a of the terminals emerge on an inside cylindrical surface of the connection part 204.

On an outer cylindrical surface of the connection part 204, 30 and located closer to the distal end, is an earth terminal 212.

The outer sheath comprises axial keyways 214 in the form of elongate slots for receiving correspondingly shaped keys of a male connector as will be described later. The keyways end in a circumferential groove 216 (Figure 5) that has a latch portion in the form of an integrally moulded, resilient pawl 218 for making a latching engagement with a key of the male connector.

Figures 7 to 11 show the male connector 30 that comprises a 10 cylindrical outer sheath 302, a cylindrical inner connection part 304 and a cable attachment portion 306.

The inner connection part 304 comprises a solid cylinder and has three hollow cylindrical electrical terminals 308 embedded therein at radially spaced locations for engagement with corresponding terminals 208 on the female connector 20, as will be described later. The terminals 308 begin within the cable attachment portion 306 and extend axially through a bulkhead 310 and stop short of a distal end of the inner connection part 304.

On an outer cylindrical surface of the connection part 304 is an earth terminal 312.

The outer sheath comprises keys 314 in the form of generally rectangular projections that are circumferentially spaced around the outside surface of the sheath, for engagement with corresponding keyways of the female connector as will be described later.

Referring to Figures 6 and 10 these show, respectively, the female and male connectors from the proximal, or cable attachment ends. The terminals 208, 308 are accessible for making crimped connections around incoming fire-retardant cables (not shown).

Figures 12 and 13 show the male 20 and female 30 connectors connected together. When forming a union, the outer sheath 302 of the male connector 30 is inserted within the outer sheath 202 of the female connector. The two sheaths are dimensioned so that a close friction fit can be made. The male part 304 then enters the female part 204 and the respective earth terminals 312, 212 make contact first before the terminals 308 and 208 make contact.

The female terminals 208 are resilient and bend slightly 15 when brought into to contact with the terminals 308, thus ensuring that a contact is maintained.

In the example shown in the drawings there is a pair of keys 314 on the outer cylindrical surface of the sheath 302 that correspond in their circumferential positions with a pair of keyways 214 on the inside cylindrical surface of the outer sheath 202 of the female connector. Once the keys have reached the annular slot 216 the male connector can be rotated with respect to the female connector. After rotation one of the keys 314 slideably engages the resilient pawl 218 which temporarily deforms before sliding past the key and returning to its original position, trapping the key, as a tooth, behind the pawl and preventing counter rotation, and hence realignment of the key with the keyway and axial separation of the male and female connectors.

Therefore the engagement of the male and female connectors is first an axial sliding for electrical connection, followed by a rotational locking motion.

The numbers and positions of the keys and their corresponding keyways can be changed, so that compatibility between connections can be made exclusive to a particular system, and thus inappropriate connections can be prevented. Also, cables and connector mouldings can be made in different colours to differentiate the system's use.

The connection system according to the present invention has a number of advantages over the prior art. Firstly, the terminals are axially recessed within the sheaths, so that it is not possible to touch a "live" terminal. This ensures that both the male and female connectors can comply with the so-called standard European "finger test" IP2X, when disengaged.

Secondly, the sheaths provide insulation for the terminals from external ambient high temperatures. Also, the relatively low mass of metal used is an advantage in a fire-retardant system as metal can draw heat from a high-temperature environment.

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 referred to herein, and/or shown in the drawings, whether or not particular emphasis has been placed thereon.

Claims

CLAIMSI. A fire-retardant electrical connection system comprising at least one connector of a first type and at least one connector of a second type for connecting together, wherein the connectors each comprise an outer sheath, an inner connection part and one or more electrical terminals, and wherein connectors are arranged in use for engagement such that when connected they form a heat-resistant shield around the terminal.
2. A system according to Claim 1, wherein the sheath of the one connector is arranged in use to locate within the sheath of the other connector.
3. A system according to Claim 2, wherein the sheath of the one connector slides within the sheath of the other connector.
4. A system according to any of Claims 1 to 3, wherein the connectors comprise a proximal, or cable end and a disLal, or open end.
5. A system according to Claim 4, wherein the cable end may be arranged in use to be connected to one or more cables or wires, preferably by crimping.
6. A system according to any of Claims 1 to 5, wherein the inner connection parts comprise the terminals for making an electrical connection.
7. A system according to Claim 6, wherein the inner connection part of the connector is axially spaced from the open end of the outer sheath.
B. A system according to any of the preceding claims, wherein the connection parts are arranged such that when the connectors are engaged in use an electrical connection is made between at least one terminal of each connection part.
9. A system according to any of the preceding claims, wherein the connectors are arranged in use to become physically locked together.
10. A system according to Claim 9, wherein the connectors are arranged in use to become locked together by engagement of a first latch portion on one of the connectors and a second latch portion on the other of the connectors.
11. A system according to Claim 10, wherein the latch portions are arranged in use for releasable engagement with each other.
12. A system according to Claim 10 or 11, wherein thc first latch portion comprises a tooth portion and the second latch portion comprises a pawl portion.
13. A system according Lo any of Claims 10 to 12, wherein engagement of the latch portions is arranged in use to be brought about by relative movement between the connectors.
14. A system according to Claim 13, wherein said relative movement comprises relative rotational movement between the connectors.
15. A system according to any of the preceding claims, wherein one of the connectors comprises at least one key and the other of the connectors comprises at least one keyway, such that during engagement connectors the or each key engages with a keyway for relative axial and/or relative movement of the connectors.of the respective rotational
16. A connector for use in a connection system according to any of Claims 1-15.
17. A cable attached to a connector according to any of Claims 1-16.
18. A method of making a fire-retardant electrical connection between connectors, each connector comprising an outer sheath, an inner connection part and at least one electrical terminal, wherein the method comprises engaging the connectors such that when connected they form a heat-resistant shield around the terminal.
19. A method according to Claim 18, comprising physically locking together the connectors by engagement of a first latch portion on one of the connectors and a second latch portion on the other of the connectors.
20. A method according to Claim 18 or 19, wherein the method comprises connecting the connectors electrically by relative axial movement and locking them physically by relative rotational movement.