GB2332306A

GB2332306A - Power track system

Info

Publication number: GB2332306A
Application number: GB9721894A
Authority: GB
Inventors: David Charles Peter Harrison
Original assignee: Ackermann Ltd
Current assignee: Ackermann Ltd
Priority date: 1997-10-15
Filing date: 1997-10-15
Publication date: 1999-06-16
Also published as: GB2332306A9; GB9721894D0

Abstract

A power track system has conductors (12, 14, 16, 18 and 34) for providing dual power supplies (for example normal and clean power supplies) and tap-off points at which pinned plugs (for example 26) can be inserted to tap off power. Each tap-off point and plug has one of two possible configurations so that a plug, for tapping into one power supply cannot be inserted into a tap-off point for the other power supply and vice versa. Conveniently, the track of the system has a conductive casing which provides the earth connection for one of the power supplies. Preferably, each type of plug and tap-off has a respective polarizing pin 30 and hole 30A. A plug may have six pins 12A to 22A. Pins 12A to 20A mate with corresponding contacts of a tap-off. Pin 22A connects to a metal casing of the track. An insulating pin 28 operates a shutter (not shown).

Description

1 Title Power Track Syste

Field of the Invention

This invention relates to a power track system.

Background to the Invention

2332306 Power tracks, sometimes known as busways, are frequently used for distributing power in buildings. The powertrack is usually located under the floor, and the floor is provided with points at which power can be tapped off. Power tracks are known which provide dual power supplies and, in this case, it can be important that the power supply tapped into is appropriate for the equipment which is to draw power.

The Invention According to the invention, there is provided a power track system having conductors for providing dual power supplies, and tap-off points at which pinned plugs can be inserted to take off power, wherein means are provided whereby a plug for tapping into one power supply cannot be inserted into a tap-off point intended for take off of power from the other power supply, and vice versa.

The invention is preferably applied, in particular, to a power track system providing normal (standard) and clean power supplies. For this purpose, the track is required to possess six conductors, namely live, neutral and earth conductors for the normal power supply and live, neutral and earth conductors for the clean power supply. In this preferred power track system, the normal earth conductor is conveniently provided by the track casing.

2 According to another feature of the invention, a preferred plug for cooperating with the preferred power track has six pins, one of which, on insertion of the plug into the track, makes electrical contact with the track casing. The other five pins pass in insulated manner through the casing each to engage one of five internal track conductors. Insulation of the lastmentioned five pins from the casing is preferably achieved by means of a sleeve or spacer of insulating material around the base region of each pin. These five pins are preferably split pins for resiliently clasping the respective track conductors, which may be in the form of conductive strips. The first mentioned normal earth pin for engagement with the casing may also be a resilient pin, in use passing through an edge aperture in the top wall of the track casing, for example to bear against the interior of the casing side wall. On the top wall of the track, the pin apertures, which may be split to match the split pins, are preferably located within the confines of this top plate, serving for reinforcement and/or insulation.

It will be apparent that, within the body of the plug, only the pins appropriate to one power supply need be wired up. it is still necessary, however, for complete isolation of one power supply from the other, to ensure that a plug attached to equipment requiring a normal power supply is not insertable into the track at a tap-off point intended for insertion of a plug attached to equipment requiring a clean power supply, and vice versa, and various means are possible to achieve this.

For example, the pins may be arranged in a different formation on a normal supply plug from the formation on a clean supply plug, each to match apertures of corresponding differing formations at different tap- off points.

Preferably however, the five pins are arranged in the same staggered formation on both types of plug, but coded pegs and holes, respectively on the plug and in the track for preference, are provided. The pegs and holes may be coded by 1 3 their cross-sectional shapes, so that the peg (or hole) on a plug for drawing power from the normal power supply does not match the hole (or peg) provided on the track at a clean power supply tap-off point, and vice versa. However, a peg (or hole) on a normal power plug for insertion at a normal power supply tap-off point will match the hole (or peg) on the track, and thus be fully insertable. The same will be true for a clean power supply plug and clean power track tap-off point.

Conveniently, plugs of both types may be provided with lipped wings for clasping longitudinal extending ribs extending along the outside of the side walls of the track.

In addition to the afore-described pins and pegs, the plug preferably has a pin for opening a sliding shutter beneath the top wall of the track and, as an additional safety feature, the earth pins are preferably longer than the other four pins, so that earth connections are fully established before the remaining pins engage the live and neutral internal track conductors.

Description of Embodiment

The invention is further described with reference to the accompanying drawings, in which:- Figure 1 is a perspective view of the track and a plug f or insertion at a tap-of f point in the track; and Figure 2 is an elevational view of a slightly modified track and plug, wherein the track appears in transverse crosssection.

Referring to the drawings, a power track 10 has five internal conductors, generally in the form of conductive strips 12 to 20, and a sixth conductor provided by the power track casing 22. In Figure 1, the internal track conductors are not 4 visible. Conductors 12 and 14 are the live and neutral conductors for a normal power supply, and conductors 16 and 18 are the live and neutral conductors for a clean power supply.

Conductor 20 is the clean power supply earth line; the earth line for the normal power supply is provided by the track casing.

A power tap-off point is indicated at 24, at which a plug 26 can be inserted into the track to draw power. The tap-off point indicated may be specifically for the normal power supply or specifically for the clean power supply, the plug 26 being internally wired accordingly.

However, except for the internal wiring and a coded peg to be described later, the plugs for normal and clean power take off are identically arranged.

Thus, the illustrated plug has five pins 12A to 20A in staggered formation, matching the staggered formation of pin apertures 12B to 20B in the top wall of the track casing 22, and a sixth pin 22A for engaging into the aperture 22B at the edge of the top wall of the track casing.

The plug has a further pin 28, with a tapered end, which operates a sliding shutter (not shown) beneath the top wall of the track at the tapoff point.

Moreover, the plug has a peg 30, shown with L-shaped crosssectional shape in Figure 1, for engagement into a corresponding L-shaped aperture 30A in the top wall of the track. This is where a plug for normal power take-off differs from a plug for clean power take-off, in that a plug and tapoff point intended for normal power take-off utilise a peg 30 and aperture 30A of different cross-setional shape from the cross-sectional shape of the peg 30 and aperture 30A of a plug and tap-off point intended for clean power take-off. This means that a plug connected to equipment requiring a normal 1 power supply cannot be inserted into the track at a tap-of f point intended for clean power take-off, and vice versa. The coded peg 30 is not visible in Figure 2, being hidden by the shutter pin 28, which differs in shape from the shutter pin 28 shown in Figure 1.

Figure 2 clearly shows, however, that in addition to the saf ety feature provided by the shutter and shutter pin, the earth pins 20A (for clean power supply) and 22A (for normal power supply) are both longer than the pins 12A to 18A, so that earth connections are fully established before the last-mentioned pins engage the internal live and neutral track conductors.

The plug 26 has somewhat resilient, lipped wings 32 for engaging with external longitudinal ribs 34 on the outside side walls of the track when the plug is fully inserted, thus preventing accidental pulling out of the plug due to a pull or tug on the plug cable 36.

Additionally, at each power tap-off point, the track may be provided with a shaped, apertured top plate 38, serving for reinforcement and/or insulationg purposes.

It will be appreciated that the coded peg and track aperture system above described is applicable to many kinds of dual power supply track other than that described, with which may cooperate plugs of different construction to the plug illustrated and above described.

Reference numeral 40 denotes a steel strip welded to the casing 22 to lower the electrical resistance of the normal earth path.

6 C808/A

Claims

Claims

A power track system having conductors for providing dual power supplies, and tap-off points at which pinned plugs can be inserted to take off power, wherein means are provided whereby a plug for tapping into one power supply cannot be inserted into a tap-off point intended for take off of power from the other power supply, and vice versa.
2. A power track system according to claim 1, in which the system includes means for providing normal and clean power supplies.
3. A power track system according to claim 2, in which the system includes a track having six conductors, namely live, neutral and earth conductors for the normal power supply and live, neutral and earth conductors for the clean power supply.
4. A system according to claim 3, in which the track includes a conductive casing and at least one tap-off paint includes means for connecting the normal earth pin of a plug inserted therein to the casing, the casing. in use, constituting the normal earth conductor.
5. A power track system according to any of claims 1 to 4, in which the system includes a track having a top wall in which a series of apertures for the -Dins of a plug are located, the apertures being located within the confines of the top wall, the latter serving as reinforcement for the track and/or insulation between the pins and the casing.
6. A plug for cooperating with a power track system according to claim 4, the plug having six pins, one of which, on insertion of the plug into the track, makes electrical contact with the track casing, the other five pins passing -n insulated manner through the casing each to engage a respective 1 7 one of five internal track conductors.
7. A plug according to claim 6, in which insulation of the last-mentioned five pins from the casing is achieved by means of a sleeve or spacer of insulating material around the base region of each pin.
8. A plug according to claim 6 or claim 7, in which said five pins are split pins for resiliently clasping the respective track conductors.
9. A plug according to any of claims 5 to 8, in which said pin for engagement with the casing is a resilient pin, in use passing through an edge aperture in the top wall of the track casing to bear against the interior of the casing side wall.
io. A power track system according to claims 1 to 5 and a plug according to claims 5 to 8.
11. A plug and power track system according to claim 10, in which the plug is one of a pair of such plugs, each adapted for connection to a tap- off point of a respective type, both plugs having five pins arranged in the same staggered formation, but at least one plug having a coded peg for insertion into a corresponding aperture in the respective type of tap- off point, the arrangement being such that said peg enables the plug to be inserted into said tap-off point, but that plug is prevented from being inserted into said other type of tap-off point.
12. A power track system and plugs according to claim 11, in which the other plug includes a different coded peg to enable insertion into the corresponding type of tap-off point, either plug not being insertable into the or each tap-off point at which the aperture f or a coded peg does not match the coded peg of that plug.

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13. A power track system and plugs according to claim 11 or claim 12, in which the pegs and holes are coded by their crosssectional shapes, so that the peg (or hole) on a plug for drawing power from the normal power supply does not match the hole (or peg) provided on the track at a clean power supply tap-off point, and vice versa.
14. A power track system and plugs according to any of claims 11 to 13, in which plugs of both types are provided with lipped wings for clasping longitudinal extending ribs extending along the outside of the side walls of the track.
is. A plug according to any of claims 6 to 9, in which the earth pin is longer than the other four pins, so that earth connections are fully established before the remaining pins engage the live and neutral internal track conductors.
i6. A power track system substantially as described herein with reference to, and as illustrated in, the accompanying drawings.
17. A plug substantially as described herein with reference to, and as illustrated in, the accompanying drawings.

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