GB2544068A

GB2544068A - Improvements for an electrical supply unit

Info

Publication number: GB2544068A
Application number: GB1519489.7A
Authority: GB
Inventors: Capuzza Rossano
Original assignee: Individual
Current assignee: Individual
Priority date: 2015-11-04
Filing date: 2015-11-04
Publication date: 2017-05-10
Anticipated expiration: 2035-11-04
Also published as: GB201519489D0; GB2544068B

Abstract

An electrical supply unit 100 comprising: a sealable container having an interior and being moveable between an open position, in which the interior may be accessed by a user and a closed position, in which the interior may not be accessed by a user; and one or more charging points 13 located in the interior of the container that are operable to provide a first supply of electricity when the container is in the closed position and operable to provide a second supply of electricity (which may be zero) when the container is in the open position, wherein the second supply of electricity is at a lower voltage than the first supply of electricity; and a detection arrangement to detect whether the container is in the open position or in the closed position; and a control means adapted to monitor the current drawn by each of the one or more charging points 13 and, if the detection arrangement indicates that the container is in the closed position and the current drawn by one of the one or more charging points 13 varies in a pre-determined manner, reducing the first supply of electricity at least to the one or more charging points to zero or to a non-zero voltage, lower than the first supply of electricity, wherein the control means is deactivated when the detection arrangement indicates that the container is in the open position. Also disclosed is a container with a plurality of charging compartments containing charging points that are operable to supply electricity when the compartment is closed.

Description

Title: Improvements for an electrical supply unit Description of Invention

This invention relates to a unit for supplying electricity, in particular for use in environments that have regulations which require a supply of electricity that is different from “mains” voltage, such as building sites.

For convenience, many users use portable, battery powered tools on building sites. A wide range of portable tools are available, such as electric drills, electric screwdrivers, electric saws, electric wrenches or electric grinders. Typically, batteries that are used with portable tools do not hold enough charge to provide a day of use; a user either charges the depleted battery or replaces the depleted battery with a charged battery. The user has a choice of taking a plurality of fully charged batteries to work or alternatively, to charge any depleted batteries at work.

If the user takes a plurality of fully charged batteries to a building site, the user has the substantial cost of buying multiple batteries, the ongoing inconvenience of carrying the batteries around the building site and the user may become a target for thieves. Typically, the user will take two or three batteries to work and will charge a depleted battery at work.

Regulations and laws in different countries may require that voltages lower than “mains” voltage are made available to users in certain environments. For example, in the United Kingdom “mains” voltage is rated at 230 V and there is a requirement that power outlets on building sites do not provide an electricity supply at “mains” voltage. Power outlets on building sites in the United Kingdom are required to supply a lower voltage, typically at 110 V. Charging a battery from a 110 V supply is very slow when compared to charging a battery from a “mains” supply. The rate of charging a battery from a 110 V supply is so slow that it is not a practical option for many users.

As charging batteries from a 110 V supply is so slow, any power outlets near a building site that are at “mains” voltage, such as in a contractor’s office, tend to be used for the charging of batteries for power tools. The charging of batteries in a contractor’s office tends to be disruptive for staff working in the contractor’s office as it results in a number of people coming and going throughout the day and it limits the number of power supplies that the staff in the contractor’s office can use. Safety issues may also arise if a large number of users charging their batteries overload a limited number of “mains” voltage supplies. Many building sites prevent users from charging their batteries in the contractor’s office.

If the user is on a building site where, for example, an office block is being built and the user is working above ground level, it is inconvenient for the user to make multiple journeys up and down the office block in order to go to the contractor’s office to charge their batteries.

It is recognised in the art that there is a need for a power supply unit that is able to provide “mains” voltage for charging batteries but prevents users from accessing “mains” voltage for other uses. Typically, these devices use a detection mechanism comprising one or more switches, which detect when the power outlet is accessible to a user. If the power outlet is accessible to the user, the voltage is reduced to a safer voltage. However, the users may circumvent the detection arrangement on these devices so that “mains” voltage may be accessible to the user when it should not be accessible. GB2446013 discloses an electrical supply unit, comprising a sealable container having an interior and being moveable between an open state, in which the interior may be accessed by a user and a closed state, in which the interior may not be accessed by a user. One or more charging points are located in the interior of the container, each charging point being operable to provide a first supply of electricity when the container is in the closed position and operable to provide a second supply of electricity when the container is in the open position. A detection arrangement may be provided to detect whether the container is in the open or closed position. The second supply of electricity may be zero. GB2330959 discloses a battery charging rack having a cabinet with a plurality of closeable bays each arranged to receive one or more rechargeable batteries, and charging means coupleable to one or more batteries in each bay. Each bay has a door which seals against a door frame when closed. Any gas build up during charging is removed via a ventilation passage linked to ducts through an exterior wall of a building, and a ventilation fan may be turned on by a gas sensor and/or when a liquid spill is sensed by a detector. Each door may be hinged along a lower edge so as to form a horizontal platform when open as an aid to battery loading/unloading. Alternatively, each door may be hinged at a vertical side edge and may have a battery receiving tray fixed to it. Each door may also have an interlock switch such that power is only supplied to a battery when the door is closed. A coin release mechanism may be associated with each bay. A battery charging control unit may control charging in response to a payment mechanism.

It is desirable to have an electricity supply unit that is able to supply electricity at “mains” voltage in order to charge batteries at a useful rate and at the same time, effectively protect users from being exposed to “mains” voltages in unsafe environments.

The present invention aims to address at least some of these problems.

The present invention relates to an electrical supply unit, comprising: a sealable container having an interior and being moveable between an open position, in which the interior may be accessed by a user and a closed position, in which the interior may not be accessed by a user; and one or more charging points located in the interior of the container, the one or more charging points being operable to provide a first supply of electricity when the container is in the closed position and operable to provide a second supply of electricity, when the container is in the open position, wherein the second supply of electricity is at a lower voltage than the first supply of electricity; and a detection arrangement to detect whether the container is in the open position or in the closed position; and a control means adapted to monitor the current drawn by each of the one or more charging points and, if the detection arrangement indicates that the container is in the closed position and the current drawn by one of the one or more charging points varies in a predetermined manner, reducing the first supply of electricity at least to the one or more charging points to zero or to a non-zero voltage, lower than the first supply of electricity, wherein the control means is deactivated when the detection arrangement indicates that the container is in the open position.

Preferably, the first supply of electricity is reduced to zero if the detection arrangement indicates that the container is in the closed position and the current drawn by the one or more charging points varies from a predetermined current profile by more than a pre-determined amount.

Preferably, the pre-determined manner of variation is that the current drawn by the one or more charging points is larger than a pre-determined threshold.

Preferably, the pre-determined manner of variation is that the current drawn by the one or more charging points changes more quickly with respect to time than a pre-determined threshold.

Preferably, the pre-determined manner of variation is that the current drawn by the one or more charging points changes between a first current value and a second current value over a fixed amount of time more than a pre-determined threshold.

Preferably, the pre-determined manner of variation is that the current drawn by the one or more charging points is greater than a first current value, wherein the first current value is the current drawn when the charging point initially supplies electricity to an electronic device plugged into the charging point.

Preferably, the current profile comprises the current drawn declining smoothly from an initial value towards a second, lower value.

Preferably, the second supply of electricity is zero.

Preferably, the second supply of electricity is at a non-zero voltage, lower than the first supply of electricity.

Preferably, the container is lockable in the closed position.

Preferably, the first supply of electricity may only be provided when the container is locked in the closed position.

Preferably, the container comprises a closure which is moveable between a first configuration, in which the container is in the open position, and a second configuration, in which the container is in the closed position, and in which first and second contacts are respectively provided on the closure and on a further part of the container, the contacts coming into contact with one another when the closure is in the second configuration but not contacting one another when the closure is in the first configuration.

Preferably, the first and second contacts are used as part of the detection arrangement.

Preferably, the detection arrangement further comprises a light sensor, the detection arrangement configured such that the light sensor indicates when the container is in the open position or the closed position.

Preferably, the container is of sufficient size to accommodate a power tool or battery pack thereof for each of the charging points within the interior of the container when the interior is in the closed position.

The present invention may also relate to an electrical supply unit, comprising: a container having an interior, a plurality of compartments located within the interior of the container, each compartment being moveable between an open position, in which the compartment may be accessed by a user, and a closed position, in which the compartment may not be accessed by a user; and one or more charging points located in each compartment, the one or more charging points being operable to provide a first supply of electricity when the compartment is in the closed position, wherein each compartment has a first contact and the interior has a corresponding second contact, the contacts configured such that when each compartment is in the closed position, the first contact of that compartment is in contact with the corresponding second contact and the first supply of electricity may be provided to the one or more charging points of that compartment, the contacts being further configured such that when each compartment is in the open position, the first contact of that compartment is not in contact with the corresponding second contact and there is no supply of electricity to the one or more charging points located in the compartment.

Preferably, each compartment may be moved between the open position and the closed position without affecting the supply of electricity to any of the other compartments.

Preferably, the movement of each compartment from the closed position to the open position physically separates the first contact and the second contact.

Preferably, the electrical supply unit further comprises a detection arrangement to detect whether one of the plurality of compartments is in the open position or the closed position.

Preferably, the first supply of electricity is reduced to zero or to a non-zero voltage, lower than the first supply of electricity, if the detection arrangement indicates that the container is in the closed position and the current drawn by one of the one or more charging points varies in a pre-determined manner, wherein the control means is deactivated when the detection arrangement indicates that the container is in the open position.

Preferably, the current profile comprises a first value and declines smoothly to a second value.

Preferably, one or more of the plurality of compartments is lockable in the closed position.

Preferably, one or more of the plurality of compartments is configured to be locked and unlocked with an external electronic device that is paired with an individual compartment.

Preferably, the first supply of electricity may only be provided to one of the plurality of compartments when that compartment is locked in the closed position.

Preferably, the one or more compartments are of sufficient size to accommodate a power tool or battery pack thereof for each of the charging points within the interior of the compartment when the compartment is in the closed position.

Preferably, the electrical supply unit is configured such that the first supply of electricity is limited to a non-zero current value, and if the current drawn by the one or more charging points exceeds the non-zero current value, the first supply of electricity is reduced to zero.

Preferably, the electrical supply unit further comprises one or more charging indicators on the exterior of the electrical supply unit, each charging indicator corresponding to a charging point and configured to indicate to a user the charge of an item connected to the corresponding charging point.

Preferably, the one or more charging indicators are flush with, or lower than the level of, the exterior of the electrical supply unit.

Preferably, the plurality of charging points have a common earth.

In order that the present invention may be more readily understood, embodiments thereof will now be described, by way of example, with reference to the accompanying drawings, in which:

Fig. 1 is a schematic view of a unit for supplying electricity to a user according to an embodiment of the present invention; and

Fig. 2 is a schematic view of a unit for supplying electricity to a user according to an embodiment of the present invention; and

Fig. 3 is a schematic view of a unit for supplying electricity to a user according to an embodiment of the present invention.

The embodiment shown in Fig. 1 comprises a first electrical supply unit 100 (only part of which is shown). The electrical supply unit 100 comprises a container 11. The container 11 has a rectangular base 16. The container further comprises an elongate first side 17, a short second side 18, an elongate third side 19, and a short fourth side 20, each of the vertical edges of the first, second, third and fourth sides 17, 18, 19, 20 are each joined to the edges of the adjacent sides, such that a continuous wall is formed around the rectangular base 16. Each of the bottom edges of the first, second, third and fourth sides 17, 18, 19, 20 are joined to one of the edges of the rectangular base 16, with the elongate sides 17, 19 each joined to one of the elongate edges of the base 16 and the short sides 18, 20 each joined to one of the short edges of the base 16.

Diametrically opposite to the base 16 of the container is an opening, through which the user may access the interior of the container 11. The container 11 also comprises a lid 12 that is connected with a hinge to the elongate first side 17 of the container 11. The lid 12 may be opened, such that the electrical supply unit 100 is in an open position, in which the interior of the container 11 is accessible to the user. The lid 12 may be closed, such that the electrical supply unit 100 is in a closed position, in which the interior of the container 11 is not accessible to the user. The lid 12 is of a size such that it covers the opening of the container 11 and is flush with the first, second, third and fourth sides 17, 18, 19, 20 of the container 11 when the lid 12 is closed. Overall it will be understood that the electrical supply unit 10 takes the form of a box with a hinged lid 12.

Attached to the base of the container 11 and in the interior of the container 11 are six sockets 13 (although more or fewer may be provided), into which the user may plug electrical appliances when the electrical supply unit 100 is in the open position. Passing through the exterior of the short fourth side 20 into the interior of the container 11, is an external power supply cable 15. The external power supply cable 15 is connected to a transformer (not shown) within the electrical supply unit 100 and the transformer supplies power to each of the six sockets 13. Connected to the sockets 13, attached to the base 16 of the container 11 and in the interior of the container 11, is a control unit 14. The control unit 14 controls how the transformer alters the supply of electricity to each of the sockets 13.

Fig. 2 depicts the electrical supply unit 100 in the closed position. The electrical supply unit 100 comprises a detection arrangement 16, which is communicatively coupled to the control unit 14. The detection arrangement 16 comprises two metal contacts that complete a circuit when the lid 12 is in the closed position. A first metal contact is on the exterior of the lid 12 of the container 11, adjacent to the edge of the lid 12 opposite to the hinge. A second, corresponding, metal contact is on the exterior of the elongate third side of the container 11. When the lid 12 is in the closed position, the two contacts touch one another and form an electrical connection therebetween. When the lid 12 is in the open position, the metal contacts no longer form a circuit and the detection arrangement 16 indicates to the control unit 14 that the lid 12 is in the open position.

The electrical supply unit 100 preferably further comprises a locking mechanism for locking the lid 12 of the container 11 in the closed position. In the embodiment shown, the locking mechanism comprises a hasp 17 and a loop 18. The hasp 17 is attached to the exterior of the lid 12 and extends over the side of the lid 12 to meet the loop 18, which is attached to the exterior of the elongate third side of the container 11.

Fig. 3 shows another embodiment of the present invention, comprising a second electrical supply unit 200. The second electrical supply unit 200 comprises a container 21. As for the first electrical supply unit 100, the container 21 generally comprises a rectangular base and four upstanding walls. The interior of the container 21 comprises nine compartments 22, which are arranged in the interior of the container 21 in a three by three array. Each of the nine compartments 22 comprises a rectangular base 28, an elongate first side 29, a short second side 30, an elongate third side 31, and an open fourth side. Each of the vertical edges of the first, second and third sides 29, 30, 31 are joined to each other such that a continuous wall is formed around three sides of the rectangular base 28, there being an opening into the compartment 22 through the open fourth side. In the base 28 of each of the nine compartments 22, is a socket 25.

Each of the bottom edges of the first, second and third sides 29, 30, 31 are joined to one of the edges of the rectangular base 28, with the elongate first and third sides 29, 31 each being joined to one of the elongate edges of the base 28 and the short second side 30 being joined to one of the short edges of the base. The compartment 22 further comprises a top 33, each of the top edges of the first, second and third sides 29, 30, 31 being joined to one of the edges of the top 33, with the elongate first and third sides 29, 31 being joined to one of the elongate edges of the top 33 and the short second side 30 being joined to one of the short edges of the top 33. Each component 22 therefore takes the form of a box with one open side.

Each compartment 22 is attached to the container 21 but may move through a limited vertical range. At the bottom of the range, the top 33 of the compartment 22 is level with or below the top of the walls of the container 21. At the top of the range, the socket 25 may be level with or slightly below the level of the top of the walls of the container 21. The compartment 22 is prevented from moving further than the top of the range, in this example by an arrangement of ridges and lips. At the base of the compartment, each elongate third side 31 has a protruding ridge (not shown). When the compartment 22 is at the top of the range, the protruding ridge meets a complementary lip (not shown) that protrudes from the top of the elongate third side 31 of the adjacent compartment 22, or a complementary lip (not shown) that protrudes from the top of the side 35 of the container 21. In this way, the compartment 22 is prevented from moving further than the top of the range. An advantage of limiting the compartment to a certain range is that a first contact 26 (described in more detail below) is not accessible to the user, thereby reducing the risk of electrocution. Other arrangements of lips and ridges are contemplated, or other ways of limiting the motion of the compartment 22.

The compartment 22 is moveable between a closed position (as shown for eight of the compartments 22 shown in Fig. 3), wherein the open fourth side is not accessible to the user and an open position (shown in Fig. 3 for the one raised compartment 22), wherein the open fourth side is accessible to the user. The top 33 of the compartment 22 further comprises a handle 23, such that the user can open and close the compartment 22, such that each compartment 22 can move between the open position and the closed position.

The exterior of the elongate first and third sides 29, 31 of the compartment 22 preferably further comprise a pair of vertical runners 24, 32, 36, 37 on each of the first and second sides 29, 31. The runners 24, 32, 36, 37 are arranged so that the top of the runner is near the top 33 of the compartment 22 and the bottom of the runner is near the base 28 of the compartment 22.

On the elongate first side 29 of the container 22, the two runners 36, 37 comprise a protruding runner 36 closest to the opening of the container 22 and a recessed runner 37 closest to the short second side 30. On the elongate third side 31 of the container 22, the two runners 24, 32 comprise a protruding runner 24 closest to the short second side 30 and a recessed runner 32 closest to the opening of the container 22. The protruding runner 36 on the elongate first side 29 is complementary to the recessed runner 32 on the elongate third side 31 of the container 22. Likewise, the recessed runner 37 on the elongate first side 29 is complementary to the protruding runner 24 on the elongate third side 31 of the container 22. The two sets of complementary runners 36, 32, 37, 24 hold the compartment 22 in place and aid the user when moving the compartments between the open and closed positions.

The walls of the container 21 may also comprise pairs of recessed and protruding runners (not shown) that are complementary to the runners 24, 32, 36, 37 on the individual compartments 22 that lie adjacent the walls.

The user may plug an electrical appliance into the socket 25 when the compartment 22 is in the open position. On the base 34 of the container 21 is a three by three array of nine first contacts 26, each of the first contacts 26 corresponding to a second contact (not shown) on the base 28 of each of the nine compartments 22. The first contact 26 and the second contact form a circuit and allow the socket 25 to be supplied with electricity when the compartment 22 is in the closed position. When the compartment 22 is in the open position, the circuit between the first contact 26 and the second contact is broken and the socket 25 is no longer supplied with electricity.

Passing through the exterior of the side 35 of the container 21, into the interior of the container 21, is an external power supply cable 27. The external power supply cable 27 supplies power to each of the nine sockets 25 when the corresponding compartment 22 is in the closed position.

Use of the electrical supply units 100, 200 will now be discussed.

In use of the first electrical supply unit 100, the user connects the first electrical supply unit 100 to a power supply, for example on a building site, wherein the power supply is typically at 110 V. When the lid 12 is in the closed position, the control unit 14 instructs the transformer to step the supplied voltage up to 240 V. The 240 V supply is routed to each of the six sockets 13. When the lid 12 is in the open position, the detection arrangement 16 communicates to the control unit 14 that the lid 12 is in the open position and the control unit 14 instructs the supply of a lower voltage, which may be 110 V (in which case, the supply voltage may simply be passed directly to the sockets 13), or to stop the supply of voltage to the sockets 13 entirely. In this way, the user is never exposed to voltage at 240 V as the lid 12 is either in the open position and the voltage available at the sockets 13 is less than 240 V or the lid 12 is in the closed position and the sockets 13 are not accessible to the user.

The user may use the electrical supply unit 100 to charge a battery for a portable power tool. In use, the user will open the lid 12, plug a battery charger into one of the six sockets 13. Once the user closes the lid 12, the control unit 14 will instruct the transformer to step the voltage up to 240 V and the batteries will charge at “normal” rate. When the user opens the lid 12 again, the control unit 14 will supply a lower voltage once more.

The user may attach a padlock or the like to the locking mechanism in order to prevent unauthorised users from accessing the interior of the container 11.

When using the second electrical supply unit 200 (shown in Fig. 3), the user connects the electrical supply unit 200 to a power supply, for example on a building site, wherein the power supply is typically at 110 V. The external power supply cable 27 is connected to a transformer (not shown) located within the interior of the container 21. The transformer steps the voltage up to 240 V and the 240 V supply is routed to each of the nine first contacts 26. When one of the compartments 22 is in the open position, the circuit between the first contact 26 and the second corresponding contact on the bottom of the compartment is broken and no power is supplied to the socket 25 of that compartment. When the compartment 22 is in the closed position, and the socket 25 is not accessible to the user, a circuit is formed between the first contact 26 and the second corresponding contact on the bottom of the compartment 22 and 240 V is supplied to the socket 25.

In this way, the user is never exposed to voltage at 240 V as the compartment 22 is either in the open position and the voltage available at the socket 25 is zero, or the compartment 22 is in the closed position and the socket 25 is not accessible to the user. In preferred embodiments, the first and second contacts are arranged so that they only make contact when the compartment 22 is completely in the closed position and no gap exists through which access to the interior of the compartment 22 may be gained. The user may use the second electrical supply unit 200 to charge a battery for a portable power tool. In use, the user will open a compartment 22 and plug a battery charger into the socket 25 of the compartment 22. Once the user closes the compartment 22, the battery will charge at “normal” rate. When the user opens the compartment 22 again, the voltage available at the socket 25 will be zero. An advantage of such an electrical supply unit 200 is that it need not include a control unit, reducing the cost and the complexity of the electrical supply unit 200. However, embodiments incorporating a control unit are contemplated, as described below.

In other embodiments of the present invention, the compartment 22 may comprise a locking mechanism such that the user can put some or all of the compartments 22 in the closed position and lock the compartments 22 shut, either individually or in a block. In some embodiments, all of the compartments 22 may be lockable. In other embodiments, only a sub-set of the compartments 22 may be lockable.

In order to detect if the electrical supply unit 100, 200 is being used improperly, in some embodiments, the control unit 14 may monitor the current drawn by each of the sockets 13, 25 when high (e.g. 240 V) voltage is being supplied through the socket 13, 25. If the control unit 14 detects that the current drawn by any sockets 13, 25 varies in an unexpected manner, the control unit 14 may instruct the transformer to reduce the voltage supply by the socket, e.g. to 110 V or, alternatively, 0 V.

In some embodiments, in order to detect if the electrical supply unit 100, 200 is being used improperly, the control unit 14 may have a current profile stored in a memory and the control unit 14 may compare the current drawn by the sockets 13, 25 to the stored current profile. In some embodiments, the current profile may comprise a profile wherein the current drawn declines smoothly from an initial value towards a second, lower value. This is the expected profile during normal charging of a battery. The control unit 14 may instruct the transformer to reduce the supply of electricity to a socket 13, 25, the supply being reduced to 110 V or, alternatively 0 V, if the current drawn by the socket 13, 25 deviates from the current profile by a pre-determined amount.

In other embodiments of the present invention, when the battery is initially supplied with power, the initial current draw of the socket 13, 25 is recorded in a memory. The current profile may be expected to gently decline from the value stored in the memory when a battery is charging. If the current drawn exceeds the initial current draw that is stored in the memory at any time, this may indicate improper use of the electrical supply unit 100, 200 and the supply of electricity to the socket 13, 25 may be reduced to 110 V or, alternatively 0 V.

If the current drawn is above a certain value, this may indicate that a power tool is plugged into one of the sockets 13, 25 during normal use of the power tool. In some embodiments, the threshold value for current drawn may be in the range 2 A - 3.5 A. However, a different threshold may be employed depending on the circumstances, and indeed it is envisaged that the trend towards fast-charging batteries may require this threshold to be raised. In one embodiment, the threshold is 2 A. In another embodiment, the threshold is 3.5 A.

In some embodiments of the present invention, the electrical supply unit 100, 200 may further comprise detection means for detecting whether there is a plug plugged into the socket 13, 25. The detection means may be connected to the control unit 14. The control unit 14 may detect whether there is an immediate current draw once a plug is plugged into the socket 13, 25. When a battery is plugged into the socket 13, 25, it may start charging immediately and hence draw a current. If a power tool is plugged into the socket 13, 25 there is likely to be a measurable time between the power tool being plugged into the socket 13, 25 and the power tool being used. By detecting if there is a current drawn as soon as a plug is plugged into the socket 13, 25, this may indicate improper use of the electrical supply unit 100, 200 and the supply of electricity to the socket 13, 25 may be reduced to 110 V or, alternatively 0 V.

In other embodiments of the present invention, in order to detect if the electrical supply unit 100, 200 is being used improperly, the control unit 14 may have a value stored in a memory such that the control unit 14 can use the value to determine if the current drawn by one of the sockets 13, 25 is larger than a pre-determined threshold. If the current is larger than a pre-determined threshold, the control unit 14 may instruct the transformer to reduce the supply of electricity to the socket 13, 25 to 110 V or, alternatively 0 V.

In some embodiments, in order to detect if the electrical supply unit 100, 200 is being used improperly, the control unit 14 may monitor how quickly the current being drawn by each of the sockets 13, 25 changes with respect to time. The control unit 14 may compare how quickly the current being drawn by each of the sockets 13, 25 changes with time to a value stored in a memory. If the current varies more quickly with respect to time, than the value stored in the memory, then the control unit 14 may instruct the transformer to reduce the supply of electricity to the socket 13 to 110 V or, alternatively 0 V.

In other embodiments, in order to detect if the electrical supply unit 100, 200 is being used improperly, the control unit 14 may monitor the change in current drawn by each of the sockets 13, 25 over a fixed amount of time. The control unit 14 may compare this change to a pre-determined value stored in the memory and if the current changes more than the pre-determined amount, then the control unit 14 may instruct the transformer to reduce the supply of electricity to the socket 13, 25 to 110 V or, alternatively 0 V.

When charging a battery, a battery charger may be plugged into one of the sockets 13, 25 of the electrical supply unit 100, 200. The current drawn by the socket 13, 25 when the battery is charging is predictable. The current drawn by the socket 13, 25 will start at a first current level and will smoothly decline to a second current level as the battery charges. Even when a battery is fully charged, there may still be a predictable current draw if the battery is trickle charging.

If a user were to plug a power tool into one of the sockets 13, 25 and use the power tool when the electrical supply unit 100, 200 is in the closed position, the current drawn by the socket 13, 25 would not decline smoothly from the first current level to the second current level. Instead, the power tool would draw a relatively large amount of current as the user is using the power tool. In use, a power tool is typically used for short amounts of time, and will draw a relatively large current, for example when the user is drilling a hole. The control unit 14 may monitor how quickly the current changes with respect to time or how the current drawn changes over a fixed amount of time. An advantage of this monitoring by the control unit 14 is that the control unit 14 may detect the relatively large draw of current from a power tool when compared to the current drawn when charging a battery. If a fast charging unit is being used, the current draw may be large, but the control unit will detect that there is a continuous draw of current as opposed to the bursts of current draw that will be detected when a power tool is in use. If the control unit 14 detects a current draw that indicates that the electrical supply unit 100, 200 is not being used for charging batteries, it may indicate to the transformer to reduce the voltage supplied to the socket 13, 25.

An advantage of embodiments that detect if the electrical supply unit 100, 200 is being used improperly, is that if the user tampers with the electrical supply unit 100, 200 (for instance by drilling through the exterior of the electrical supply unit 100, 200) and plugs a power tool into one of the sockets 13, 25 when electrical supply unit 100, 200 is in the closed position, the control unit 14 will compare the current drawn by each of the sockets 13, 25 to a parameter or parameters stored in the memory (as detailed above) and will reduce the supply to 110 V or, alternatively 0 V if tampering is detected. Two or more parameters may be used in combination with other measurements in order to detect whether or not the electrical supply unit 100, 200 is being used improperly. This means that the user cannot access the mains voltage for purposes that are not authorised.

In some embodiments of the present invention, the electrical supply unit 100, 200 may have the locking mechanism connected to the control unit 14. The control unit 14 may only instruct the transformer to step the voltage up to 240 V when the locking mechanism is in the locked position.

In other embodiments of the present invention, no locking mechanism may be present on the lid of the container 11 and the control unit may only receive an input from the detection arrangement 16 that the lid 12 is in the closed position before instructing the transformer to step the voltage up to 240 V.

In some embodiments of the present invention, the detection arrangement 16 may be different from the arrangements described above. The control unit may receive an input from a detection arrangement comprising a light sensor positioned in the interior of the container 11. Once the control unit 14 has received an input from the light sensor that the light level has fallen below a certain level, (indicating that the lid 12 is in the closed position) the control unit 14 may instruct the transformer to step the voltage up to 240 V.

In other embodiments of the present invention, the detection arrangement may comprise one or more push-switches positioned on the interior of the container 11. The push switch may be in contact with the lid 12 or the base of the compartment 22 and switch between “on” and “off”, as the lid moves between the open and closed positions. The push switch may be either an “open to make” or an “open to break” push switch. The push switch may indicate to the control unit 14 whether the lid 12 is in the open or the closed position. Once the control unit 14 has received an input from the push switch indicating that the lid 12 or the compartment 22 is in the closed position, the control unit 14 may instruct the transformer to step the voltage up to 240 V. In some embodiments, the control unit 14 may not be present and the switch may directly break a circuit, for instance between the transformer and the socket 13, 25.

Any of the detection arrangements described above may be used in isolation or in combination with each other in order to achieve and effective detection arrangement for detecting whether the lid 12 or the compartment 22 is in the open or closed position. An advantage of using multiple detection arrangements is that it is more difficult for the user to bypass the detection arrangement and improperly have access to the 240 V supply of electricity.

In some embodiments of the present invention, the spacing of the sockets 13, 25 and the size of the interior of the container 11 or compartment 22 is such that a power tool or the battery pack of a power tool may be accommodated by each of the sockets 13, 25.

In other embodiments of the present invention, the interior of the container 11 or the compartment may contain any number of sockets 13, 25.

In some embodiments of the present invention, the transformer may comprise a monitoring unit for monitoring the voltage of the external electrical supply.

The monitoring unit may have a voltage value stored in a memory, the value being that which needs to be supplied to the sockets 13, 25. The monitoring unit may calculate how the voltage of the external electrical supply needs to be altered in order to change the voltage of the external electrical supply to that stored the memory. The monitoring unit may provide instructions to the transformer to step-up or step-down the external electrical supply based on this calculation. This embodiment has the advantage that the electrical supply unit 100, 200 may be used with varying input voltages and the voltage supplied to the socket 13, 25 will be the same.

Other embodiments of the present invention may comprise means for pairing the locking mechanism with an external electronic device such as a smartphone, a tablet device or a smartwatch. In some embodiments, each socket 13, 25 may be pair-able with an external electronic device. The pairing mechanism may comprise a wireless pairing mechanism and may take advantage of a unique characteristic of the electronic device, such as a MAC address. Once the electronic device has been paired, the locking mechanism may unlock. Alternatively, the pairing mechanism may be communicatively connected to a switch and may switch an individual socket 13, 25 on or off.

Some embodiments of the present invention may comprise a charging indicator on the exterior of the container 11, 21, such as a light or an alarm. The charging indicator may be flush with the exterior of the electrical supply unit 100, 200. The charging indicator may be communicatively coupled to the control unit 14. The control unit 14 may monitor the current being drawn by the socket 13, 25 and may signal to the charging indicator to display a first colour when the current being drawn is above a pre-determined level. Once the current drawn by the socket 13, 25 drops below a pre-determined level, the control unit 14 may signal to the charging indicator to display a second colour or, alternatively, for an alarm to sound. An advantage of such a charging indicator is that the user does not need to move the electrical supply unit 100, 200 into the open position in order to check if a battery has finished charging. By making the charging indicator flush with (or set lower than) the exterior of the electrical supply unit 100, 200, the risk of damage to the charging indicator is reduced.

Other embodiments of the present invention may have a common earth between the sockets 13, 25 and the transformer rather than individual earths for each of the sockets 13, 25 and the transformer. An advantage of a common earth is that it reduces the complexity and cost of the electrical supply unit 100, 200.

When used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms 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

CLAIMS:

1. An electrical supply unit, comprising: a sealable container having an interior and being moveable between an open position, in which the interior may be accessed by a user and a closed position, in which the interior may not be accessed by a user; and one or more charging points located in the interior of the container, the one or more charging points being operable to provide a first supply of electricity when the container is in the closed position and operable to provide a second supply of electricity, when the container is in the open position, wherein the second supply of electricity is at a lower voltage than the first supply of electricity; and a detection arrangement to detect whether the container is in the open position or in the closed position; and a control means adapted to monitor the current drawn by each of the one or more charging points and, if the detection arrangement indicates that the container is in the closed position and the current drawn by one of the one or more charging points varies in a pre-determined manner, reducing the first supply of electricity at least to the one or more charging points to zero or to a non-zero voltage, lower than the first supply of electricity, wherein the control means is deactivated when the detection arrangement indicates that the container is in the open position.

2. An electrical supply unit according to claim 1, wherein the first supply of electricity is reduced to zero if the detection arrangement indicates that the container is in the closed position and the current drawn by the one or more charging points varies from a pre-determined current profile by more than a pre-determined amount.

3. An electrical supply unit according to claim 1, wherein the pre determined manner of variation is that the current drawn by the one or more charging points is larger than a pre-determined threshold.

4. An electrical supply unit according to claim 1, wherein the pre determined manner of variation is that the current drawn by the one or more charging points changes more quickly with respect to time than a predetermined threshold.

5. An electrical supply unit according to claim 1, wherein the pre determined manner of variation is that the current drawn by the one or more charging points changes between a first current value and a second current value over a fixed amount of time more than a pre-determined threshold.

6. An electrical supply unit according to claim 1, wherein the pre determined manner of variation is that the current drawn by the one or more charging points is greater than a first current value, wherein the first current value is the current drawn when the charging point initially supplies electricity to an electronic device plugged into the charging point.

7. An electrical supply unit according to claim 2, wherein the current profile comprises the current drawn declining smoothly from an initial value towards a second, lower value.

8. An electrical supply unit according to any preceding claim, wherein the second supply of electricity is zero.

9. An electrical supply unit according to claims 1-7 wherein the second supply of electricity is at a non-zero voltage, lower than the first supply of electricity.

10. An electrical supply unit according to any preceding claim, wherein the container is lockable in the closed position.

11. An electrical supply unit according to claim 10, wherein the first supply of electricity may only be provided when the container is locked in the closed position.

12. An electrical supply unit according to any preceding claim, wherein the container comprises a closure which is moveable between a first configuration, in which the container is in the open position, and a second configuration, in which the container is in the closed position, and in which first and second contacts are respectively provided on the closure and on a further part of the container, the contacts coming into contact with one another when the closure is in the second configuration but not contacting one another when the closure is in the first configuration.

13. An electrical supply unit according to claim 12, wherein the first and second contacts are used as part of the detection arrangement.

14. An electrical supply unit according to any preceding claim, wherein the detection arrangement further comprises a light sensor, the detection arrangement configured such that the light sensor indicates when the container is in the open position or the closed position.

15. An electrical supply unit according to any preceding claim, wherein the container is of sufficient size to accommodate a power tool or battery pack thereof for each of the charging points within the interior of the container when the interior is in the closed position.

16. An electrical supply unit, comprising: a container having an interior, a plurality of compartments located within the interior of the container, each compartment being moveable between an open position, in which the compartment may be accessed by a user, and a closed position, in which the compartment may not be accessed by a user; and one or more charging points located in each compartment, the one or more charging points being operable to provide a first supply of electricity when the compartment is in the closed position, wherein each compartment has a first contact and the interior has a corresponding second contact, the contacts configured such that when each compartment is in the closed position, the first contact of that compartment is in contact with the corresponding second contact and the first supply of electricity may be provided to the one or more charging points of that compartment, the contacts being further configured such that when each compartment is in the open position, the first contact of that compartment is not in contact with the corresponding second contact and there is no supply of electricity to the one or more charging points located in the compartment.

17. An electrical supply unit according to claim 16, wherein each compartment may be moved between the open position and the closed position without affecting the supply of electricity to any of the other compartments.

18. An electrical supply unit according to claim 17, wherein the movement of each compartment from the closed position to the open position physically separates the first contact and the second contact.

19. An electrical supply unit according to claim 18, further comprising a detection arrangement to detect whether one of the plurality of compartments is in the open position or the closed position.

20. An electrical supply unit according to claim 19, wherein the first supply of electricity is reduced to zero or to a non-zero voltage, lower than the first supply of electricity, if the detection arrangement indicates that the container is in the closed position and the current drawn by one of the one or more charging points varies in a pre-determined manner, wherein the control means is deactivated when the detection arrangement indicates that the container is in the open position.

21. An electrical supply unit according to claim 20, wherein the first supply of electricity is reduced to zero if the detection arrangement indicates that the container is in the closed position and the current drawn by the one or more charging points varies from a pre-determined current profile by more than a pre-determined amount.

22. An electrical supply unit according to claim 20, wherein the predetermined manner of variation is that the current drawn by the one or more charging points is larger than a pre-determined threshold.

23. An electrical supply unit according to claim 20, wherein the predetermined manner of variation is that the current drawn by the one or more charging points changes more quickly with respect to time than a predetermined threshold.

24. An electrical supply unit according to claim 20, wherein the predetermined manner of variation is that the current drawn by the one or more charging points changes between a first current value and a second current value over a fixed amount of time more than a pre-determined threshold.

25 An electrical supply unit according to claim 20, wherein the predetermined manner of variation is that the current drawn by the one or more charging points is greater than a first current value, wherein the first current value is the current drawn when the charging point initially supplies electricity to an electronic device plugged into the charging point.

26. An electrical supply unit according to claim 21, wherein the current profile comprises a first value and declines smoothly to a second value.

27. An electrical supply unit according to claim 16-26, wherein one or more of the plurality of compartments is lockable in the closed position.

28. An electrical supply unit according to claim 27, wherein one or more of the plurality of compartments is configured to be locked and unlocked with an external electronic device that is paired with an individual compartment.

29. An electrical supply unit according to claims 27-28, wherein the first supply of electricity may only be provided to one of the plurality of compartments when that compartment is locked in the closed position.

30. An electrical supply unit according to any claims 16-29, wherein the one or more compartments are of sufficient size to accommodate a power tool or battery pack thereof for each of the charging points within the interior of the compartment when the compartment is in the closed position.

31. An electrical supply unit according to any preceding claim, configured such that the first supply of electricity is limited to a non-zero current value, and if the current drawn by the one or more charging points exceeds the nonzero current value, the first supply of electricity is reduced to zero.

32. An electrical supply unit according to any preceding claim, wherein the electrical supply unit further comprises one or more charging indicators on the exterior of the electrical supply unit, each charging indicator corresponding to a charging point and configured to indicate to a user the charge of an item connected to the corresponding charging point.

33. The electrical supply unit of claim 32, wherein the one or more charging indicators are flush with, or lower than the level of, the exterior of the electrical supply unit.

34. An electrical supply unit according to any preceding claim, wherein the plurality of charging points have a common earth.

35. An electrical supply unit substantially as hereinbefore described with reference to the accompanying drawings.

36. Any novel feature or combination of features disclosed herein.