GB2580543A

GB2580543A - Safety plug

Info

Publication number: GB2580543A
Application number: GB1918917.4A
Authority: GB
Inventors: Stephen Tetlow Luke
Original assignee: Lst Engineering Ltd
Current assignee: Lst Engineering Ltd
Priority date: 2018-12-28
Filing date: 2019-12-19
Publication date: 2020-07-22
Also published as: GB201901213D0; GB201821280D0; GB2580435A; GB201918917D0; WO2020136580A1

Abstract

An electrical plug 1 comprises a body, a live pin 12, a neutral pin 10, a live terminal and a neutral terminal (2, 3, Figure 1), and a child safety mechanism. The child safety mechanism moves the plug from a non-functional state in which the plug cannot be fully inserted into a cooperating socket, to a functional state in which it can be fully inserted into the socket. In the non-functional state, one or more of the pins may be misaligned with the corresponding hole in the socket, and/or a retractable member (30, Figure 23) may extend from the body, blocking the plug from being fully inserted into the socket. A child safety plug comprising biasing means, which biases the plug into the non-functional state when the plug is not inserted into the socket, is also provided. In this plug, the child safety mechanism may act as a switch to close an openable connection (51, Figure 1) between a pin and its respective terminal.

Description

TITLE Safety Plug

FIELD OF INVENTION

The present invention relates to electrical plugs for use with sockets. The invention is particularly useful with conventional mains plugs and sockets but can be utilised with substantially any electrical plug and socket combination.

BACKGROUND

Many electrical apparatus require connection to an electrical supply, either to power the apparatus during normal use or to charge the apparatus when battery power has become depleted. Electrical power is normally obtained from a mains electrical supply or other electrical supply from a power socket. Apparatus can be connected to the electrical supply by means of a plug inserted into the power socket.

At present there is no product or plug design, being a mains plug or other similar plug, wherein the plug itself can be locked or otherwise temporarily put in a non-functioning state stopping someone taking an electrical appliance to an uncovered live socket and plugging it in. There are only addition products that are added to the plug. Providing such a plug would be advantageous as it would provide extra safety to potentially dangerous electrical devices such as hand blender, hair straighteners, power tools etc. This would be mainly to prevent injury to children and even teenagers who may be old enough to find and understand the use of the electrical device but may not fully understand the dangers of its use.

Once a plug is locked the appliance would no longer cause electrical or physical danger as no current could flow beyond the plug, or the plug simply could not be able to be plugged into a live socket and therefore could not be used This would mean no more need to lock away or hide possible dangerous electrical appliances as it would not be possible to use the appliance without first unlocking the attached plug. In most cases this would be only a very low-cost modification but provide ultimate protection from unwanted users. Never again would you have to worry about potentially dangerous electrical items being used unsupervised Child safety mechanisms may take many forms, but the most common is a design that requires a tab to be pressed firmly as the lid is twisted, a multistep process or just a release action that is not normal or obvious. Great strength and dexterity are not always required, but the process is deliberately made to be unintuitive.

There are many safety devices for electrical plugs and socket but all of these require a product to be added to the plug or socket that prevents its use. The present invention provides a plug having a child safety mechanism. According to a first aspect, the plug is can be in a nonfunctioning state in which it cannot be fully inserted into a cooperating socket, the electrical current cannot flow and any attached appliance could not be operated. The plug is moved into a functioning state in which it can be fully inserted into a cooperating socket by operating the 113 child safety mechanism. No extra device is needed to operate the plug. According to a second aspect the plug comprises a biasing means that acts to maintain the plug in a non-functional state if the plug is not fully inserted in a cooperating socket and the child safety mechanism is not being operated. This would mean once a plug is removed from a socket it would become none-functional automatically so there would be no need to remember to activate the locking mechanism.

SUMMARY OF INVENTION

According to a first aspect, the present invention provides an electrical plug for connection to an electrical cable and cooperating socket comprising: a body; a live pin extending from the body; a neutral pin extending from the body; a live terminal for connection to a live wire located within the body, a neutral terminal for connection to a neutral wire located within the body, and a child safety mechanism; wherein the child safety mechanism can be operated to move the plug from a non-functional state in which the plug can't be fully inserted into the cooperating socket to a functional state in which the plug can be fully inserted into the cooperating socket; and in the non-functional state one or more of the pins is misaligned with a cooperative hole in the cooperating socket blocking the plug from being inserted into the socket and in the functional state the one or more of the pins is moved to align with the cooperative hole in the cooperating socket allowing the plug to be inserted into the socket; and/or the plug further comprises a retractable member and in the non-functional state the retractable member is positioned in a first position in which it extends from the body to block the plug being fully inserted into the cooperating socket and in the functional state the retractable member is positioned a second position in or on the body of the plug a second position such that the plug can be fully inserted into the cooperating socket.

The first aspect of the present invention comprises a child safety mechanism that can be operated to move the plug from a non-functional state in which the plug can't be fully inserted into a cooperating socket to a functional state in which the plug can be fully inserted into the cooperating socket. That is, unless the child safety mechanism is operated it is not possible to fully insert the plug into a cooperating socket. In embodiments of the invention it may be possible to partially insert the plug into a cooperating socket when the plug is in the non-functional state but would still remain non-functional. However, it may be advantageous that the plug cannot be inserted into the cooperating socket at all when the plug is in the nonfunctional state. This can be achieved through misalignment of one or more of the pins and/or by the positioning of the retractable member.

According to a second aspect the present invention provides an electrical plug for connection to an electrical cable and cooperating socket comprising: a body; a live pin extending from the body; a neutral pin extending from the body; a live terminal for connection to a live wire located within the body; a neutral terminal for connection to a neutral wire located within the body; a child safety mechanism, and biasing means, wherein the child safety mechanism can be operated to move the plug from a non-functional state to a functional state, and wherein the biasing means biases the plug towards the non-functional state such that when the child safety mechanism is not being operated by a user and the plug is not fully positioned within a cooperating socket the biasing means maintains the plug in, or moves the plug to, the non-functional state.

The second aspect of the present invention provides a safety plug that has a functional state and a non-functional state and that is operated by a child safety mechanism. The plug is biased towards the non-functional state by means of the biasing means. This means that when the child safety mechanism is not being operated and/or the plug is not fully inserted into a cooperating socket the biasing means will operate to move the plug to the non-functional state or keep the plug in the non-functional state. This ensures that the plug is not left in a functional state and able to be operated unless it is either in use or the child safety mechanism is being operated.

The non-functional state of the second aspect of the present invention may be any state in which the plug cannot be operated and/or cannot be fully inserted into a socket. In embodiments of the second aspect of the present invention the non-functional state may comprise the nonfunctional state of the first aspect of the present invention in which it is not possible to fully insert the plug into a cooperating socket. In embodiments of the invention the non-functional state may comprise maintaining openable connection(s) between the live pin and the live terminal and/or the neutral pin and the neutral terminal in an open position, such embodiments are described in more detail below.

In embodiments of the second aspect of the present invention wherein the non-functional state comprises the non-functional state of the first aspect of the present invention the plug will be biased towards the non-functional state such that removing the plug from a cooperating socket without operating the child safety mechanism returns the plug to the non-functional state. The biasing means may comprise one or more biasing members and/or mechanisms within the plug that act to move one or more of the pins such that they are misaligned with a cooperative hole in the cooperating socket and/or act to bias the retractable member towards the first position.

In embodiments of the second aspect of the present invention fully inserting the plug into a cooperating socket may act on the child safety mechanism to maintain the plug in the functional state. That is, a child safety mechanism may have to be moved by a user from a resting position, in which the plug is in a non-functional state, to an operating position, in which the plug is in a functional state, and be held in that position by the user when inserting the plug into a cooperating socket in order to maintain the plug in the functional state. The user may then release the child safety mechanism and an interaction between the plug and the cooperating socket will act against the biasing means to maintain the plug in the functional state. On removal of the plug from the cooperating socket the interaction will be lost and the biasing means will act to move the plug back to the non-functional state. In embodiments the interaction between the plug and the cooperating socket may, for example, comprise a face of the cooperating socket acting on the child safety mechanism to hold the child safety mechanism in position and prevent it moving back to the resting position. In embodiments of the invention the interaction between the plug and the cooperating socket may comprise the positioning of one or more pins within a cooperating hole of the cooperating socket holding said one or more pins in alignment and preventing them from moving to a misaligned position. In embodiments of the invention the interaction between the plug and cooperating socket may comprise the face of the cooperating socket preventing a retractable member moving from a second position to a first position. The skilled person will understand that many such interactions between a plug and a cooperative socket are possible and any suitable interaction may be utilised in embodiments of the present invention.

The child safety mechanism of the present invention may comprise any mechanism that is not easily operated by a young child. This includes but is not limited to mechanisms that require two or more distinct movements and/or mechanisms that require two or more separate manual actuators to be operated. In such mechanisms it may be necessary to carry out two or more of the movements or operate two or more of the actuators in sequence and/or together. It is to be understood that the skilled person will readily understand suitable child safety mechanisms that may form part of a plug according to the present invention.

The child safety mechanism of the first aspect of the present invention may comprise a switch that is required to be depressed to operate the child safety mechanism. The switch may remain depressed after being pressed or may be required to be held in a depressed position by a user.

The child safety mechanism may comprise a hidden release button that is located in a position that is not easy for a child to operate and/or that is hidden under a cover or flap. Any such cover or flap may form part of the body of the plug. The release button could even be part of the plug body that needs to be depressed A child safety mechanism of an embodiment of the present invention may comprise a twist mechanism, such as a dial or lever, that is required to be rotated or twisted in order to be operated. In embodiments of the invention the twist mechanism may be required to be depressed or pulled away from the body in order for it to be rotated or twisted, or in order for any twisting or rotation to act to move the plug from the non-functional state to the functional state. Any twist mechanism may be formed as part of the plug body. Alternatively, a twist mechanism may be mounted on the plug body.

The child safety mechanism may comprise a combination lock. The child safety mechanism may consist of a combination lock or the combination lock may be provided in conjunction with one or more other mechanisms. In embodiments of the invention the child safety mechanism consists of a combination lock and opening the combination lock moves the plug from the non-functional state to the functional state.

The child safety mechanism may comprise a removable magnetic key and a magnetic actuator located within the body. In such embodiments the removable magnetic key may be used to move the magnetic actuator located within the body without there being any need for any physical connection between the key and the actuator. The magnetic actuator is a component that acts to move the plug from the non-functional state to the functional state. The magnetic actuator may act in isolation or may act cooperatively with other components that form the child safety mechanism. In embodiments of the invention it may be necessary that the removable magnetic key remains magnetically adhered to the magnetic actuator, and thereby to the body of the plug, in order for the plug to be in the functional state. In such embodiments, the body may comprise a slot in which the removable magnetic key can be contained when the plug is in the functional state.

The child safety mechanism may be activated using magnetism and not be a removeable key but part of the plugs body. This could be a switch or any other child safety mechanism but the mechanism would act magnetically to put the plug into a functional state.

Plugs according embodiments of the present invention may have only a live pin and a neutral 30 pin In alternative embodiments the plug may further comprise an earth pin extending from the body and cooperatively located with the live pin and the neutral pin to allow the plug to be inserted into a cooperating socket having a cooperating aperture for the earth pin.

In embodiments of the invention comprising an earth pin the plug may further comprise an earth terminal located within the body for connection to an earth wire. The earth terminal may be connected to the earth pin.

Embodiments of the present invention may comprise: a first openable connection either between the live terminal and an inner end of the live pin located within the body or between the neutral terminal and an inner end of the neutral pin located within the body, and an actuation means for closing the first openable connection; wherein in the non-functional state the first openable connections is held in an opened position and operating the child safety mechanism operates the actuation means to close the first openable connection.

That is, in the non-functional state one of the neutral or live pins is disconnected from the respective neutral or live terminal, thereby rendering the plug non-functional. Thus, the child safety mechanism has to be operated to close the first openable connection and thereby connect the neutral or live pin to the neutral or live terminal in order and put the plug into the functional state.

However, as will be readily appreciated, if only one of the live or neutral pins is disconnected if the plug is fully inserted into a cooperating socket without operating the child safety mechanism there remains a possibility that a user may be exposed to an electric shock. Therefore, it may be advantageous that in the non-functional state both the live and the neutral terminals are disconnected. Therefore, in embodiments of the invention the plug comprises: a first openable connection between the live terminal and an inner end of the live pin located within the body; and a second openable connection between the neutral terminal and an inner end of the neutral pin located within the body; wherein when operating the child safety mechanism acts to operate the actuation means to close the first and second openable connections; and in the non-functional state of the electrical plug the first and second openable connections are held in an opened position.

Such embodiments are advantageous in that it is only when the first and second openable connections are closed by the actuation means that the plug will be in the functional state and be able operate. Even if fully inserted into a socket in the non-functional state the plug will not operate and will not pose a risk to a user. Further, as both the neutral and the live pins are disconnected a user cannot get an electric shock. In such embodiments of the invention the first and/or the second openable connections may be biased towards the opened position by biasing means. Suitable biasing means will be apparent to the person skilled in the art and include, but are not limited to, springs and other similar components.

Any embodiment of the present invention may be formed in the manner of any electrical plug, standard or otherwise, that is currently in use and comprises a neutral and a live pin. In advantageous embodiments of the present invention the plug is formed in the manner of a standard mains plug as used in any country or region of the world.

Further features and advantages of the present invention will be apparent from the specific description set out below.

Drawings Figures 1 to Figure 6 are basic electrical schematics of safety plugs according to the present invention; Figures 7 shows an embodiment of a safety plug according to the first aspect of the present invention, Figures 8, 9 and 10 show alternative embodiments of safety plugs according to the first aspect of the present invention; Figures 11, 12 and 13 shows further embodiments of safety plugs according to the present invention; Figures 14, 15, 16 and 17 show further embodiments of safety plugs according to the first aspect of the present invention; Figures 18 and 19 show further embodiments an alternative embodiment of the first aspect of the present invention; and Figures 20, 21, 22 and 23 show further embodiments of the first aspect of the present invention; The present invention comprises a safety plug I. As set out above, and as defined in the claims, a safety plug according to the present invention may comprise one or more openable connections. Figures 1 to 6 show basic electrical schematics of electrical plugs 1 according to the present invention comprising one or more openable connections. These schematics are included to allow the skilled person to understand the openable connections and the formation thereof Other features of the present invention are not shown in Figures Ito 6.

Figure 1 shows a schematic of a basic UK safety plug 1 with a neutral pin 10, an earth pin 11 and a live pin 12, a live terminal 2 and a neutral terminal 3 are also provided. Openable connections 51 are formed between the live terminal 2 and the live pin 12 and between the neutral terminal 3 and the neutral pin 10. Figure 1 shows the design of a UK safety plug but it could be modified to suit any plug, standard or otherwise, comprising a live pin 2 and a neutral pin 3.

Figure 2 shows a schematic of a basic UK safety plug 1 with a neutral pin 10, an earth pin 11, and a live pin 12, a live terminal 2, a neutral terminal 3, and an earth terminal 7 are also provided. Openable connections 51 are formed between the live terminal 2 and the live pin 12, between the neutral terminal 3 and the neutral pin 10, and between the earth terminal 7 and the earth pin 11, respectively. A plug boundary 50 is shown as the dotted line in the Figure.

Figure 3 shows a schematic of a basic UK safety plug 1 with a neutral pin 10, an earth pin 11, and a live pin 12, a live terminal 2 is also provided. An openable connection 51 is formed between the live terminal 2 and the live pin 12. A plug boundary 50 is shown as the dotted line in the Figure.

Figure 4 shows a schematic of a basic UK safety plug 1 with a neutral pin 10, an earth pin 11, and a live pin 12, a neutral terminal 3 is also provided An openable connection 51 is formed between the neutral terminal 3 and the neutral pin 10. A plug boundary 50 is shown as the dotted line in the Figure.

Figure 5 shows a schematic of a basic two pin safety plug 1 with a neutral pin 10 and a live pin 12, a live terminal 2 is also provided. An openable connection 51 is formed between the live terminal 2 and the live pin 12. A plug boundary 50 is shown as the dotted line in the Figure.

Figure 6 shows a schematic of a basic two pin safety plug 1 with a neutral pin 10 and a live pin 12, a neutral terminal 3 is also provided. An openable connection 51 is formed between the neutral terminal 3 and the neutral pin 12. A plug boundary 50 is shown as the dotted line in the Figure In the embodiments of Figures Ito 6, the plug I will be in a non-functional state when one or more of the openable connections 51 are open and will be in a functional state when all of the openable connections Si are closed.

Figure 7 shows an embodiment of the present invention consists of a UK plug 1 with a neutral pin 10, an earth pin 11 and a live pin 12. The electrical circuit of the plug 1 is as shown in Figure 3, described above. There is an openable connection 51 formed between a live terminal 2 and the live pin 12. The plug 1 is shown as a UK standard plug but could be modified to suit any standard plug from any other jurisdiction. A body of the plug 1 comprises a spring-loaded lid part 4 and a locking pin 6 having a connecting switch plate 22 attached. A spring 5 is provided to bias the lid part 4 to an open position. The remainder of the body of the plug is formed as a moulded main body 8. A slot is formed in the earth pin to fit the locking pin 6. When not in use the spring 5 biases the lid part to the open position, the openable connection between the live terminal 2 and the live pin 12 is open and the plug 1 is in a non-functional state. When the plug is to be used a user will squeeze the lid part 4 and the main body 8 together against the action of the spring 5. This pushes the locking pin 6 into the slot of the earth pin 11 and the switch plate 22 closes the openable connection 51 to put the plug in a functional state. The plug 1 can then be inserted into a cooperating socket (not shown) and the cooperating hole for the earth pin 11 will hold the locking pin 6 in position and thereby hold the plug in a functional state. When the plug 1 is removed from the cooperating socket the spring 5 will push the lid part 4 away from the body, open the openable connection 51 and put the plug 1 back in the non-functional state. Unless the locking pin 6 is located within the earth pin 11, the plug cannot be fully inserted into a cooperating socket In an embodiment of the present invention shown in Figures 8 to 10, a removeable magnetic key 14 is used to move a magnetic actuation means 5 from an open position (shown in Figure 8) to a closed position (shown in Figure 10). A magnet 13 is located in the actuation means S. A removeable magnet key 14 is used to move the actuation means 5 between the open and closed positions using magnetic force acting through an outer wall of the plug 1. A groove 9 is formed in a inner wall of the plug 1 from which the live, neutral, and earth pins 10, 11, 12 protrude to allow the removeable magnet key 14 to be appropriately positioned and moved.

As shown in Figure 9, when used the magnetic key 14 is slid into the groove 9 formed in the plug 1 which attracts the magnet in the actuation means 5 within the plug 1. The magnetic key 14 is slid into a position in which it is held in in position by the groove 9 thereby moving the actuation means 5 to a closed position, to complete a circuit within the plug 1 and put the plug in a functional state. In particular, as shown in Figure 9, the magnetic key 14 is positioned in a lower end of the groove 9 and then moved upwards towards the earth pin 12. At an upper end of the groove 9 the magnetic key 14 is held in position by the groove 9. Importantly there is no physical connection between the magnetic key 14 and the magnet 8 within the actuation means 5, rather the magnetic key 14 acts on the magnet 8 through a wall of the plug 1. A spring is provided to bias the actuation means 5 towards the open position in which the plug 1 is in a non-functional state.

Figures 11 to 13 illustrate embodiments of plugs 1 have differing child safety mechanisms. These figures are considered to be illustrative of potential child safety mechanisms only. Each of the plugs 1 has a child safety mechanism that can be operated to close a plurality of openable connections 51. In particular, each of the plugs 1 has the circuit shown in Figure 2, described above. Each of the plugs 1 additionally has a biasing means (not shown) that acts to bias the plug towards a non-functional state. Details of the biasing means have been omitted so that details of the child safety mechanism can be shown more clearly.

The child safety mechanism of the plug 1 of Figure 11 comprises a combination lock 20 that is used to open and close the openable connections 21. The child safety mechanism further comprises an activation switch 16 that can only be moved from an open position (shown in the left-hand image), in which the plug is in a non-functional state, to a closed position (shown in the right-hand image), in which the plug is in a functional state, once a correct combination is entered into the combination lock 20. The combination lock 20 is located on the same side of the plug 1 as the pins 10, 11, 12 to avoid anyone being able to switch off the plug 1 whilst it is plugged in to a cooperating socket. In alternative embodiments the combination lock 20 and/or switch 16 could be an alternative side of the plug.

In the embodiment of Figure 12 the child safety mechanism comprises a safety switch 18 located on plug 1. The safety switch 18 can only be operated if a set process is completed by a user, for example the safety switch 18 may be required to be depressed into the plug 1 before it can be slid.

In the embodiment of Figure 13, the child safety mechanism comprises the safety switch 18 of the embodiment of Figure 12 and an additional hidden release button 19. The hidden release button 19 has to be pressed before the safety switch 18 can be operated. This provides a two-part activation process that is more difficult for a child to operate.

According to embodiments of the first aspect of the present invention one or more pins of a plug 1 may be moved to and from a first position in a functional state of the plug in which they aligned with a cooperating socket to and from a second position in a non-functional state of plug in which they are misaligned with a the cooperating socket. Figures 14 to 21 show such embodiments.

Figure 14 shows an embodiment of a plug 1 according to the first aspect of the present invention in which the neutral pin 10 is a tilting pin that can be locked in a tilted position in which it is misaligned with a cooperating hole of a cooperating socket. The same principle could be applied to the earth and live pins 11, 12 or any combination of the neutral, live, and earth pins 10, 11, 12 in alternative embodiments. In the embodiment of Figure 14 a child safety mechanism 21, which may be any suitable child safety mechanism, is used to rotate a tab 41 from a first rotational position, shown in the left-hand image, to a second rotational position, shown in the right-hand image. When the tab 41 is in the first position, the neutral pin 10 is pivoted to a tilted position and the plug 1 is in a non-functional state. When the tab 41 is in the second position, the neutral pin 10 is in a position in which it is aligned with the other pins 11, 12 and is aligned with a cooperating hole of a cooperating socket. This is achieved by the tab 41 engaging with an inner end of the neutral pin 10 in the first position to act to tilt the pin away from the vertical. The neutral pin 1 0 is biased towards the aligned position such that when the tab 41 is brought out of engagement with the neutral pin 10 it moves to the aligned position.

Figure 15 shows an embodiment of a plug 1 according to the first aspect of the present invention in which both the neutral pin 10 arid the live pin 12 are tilting pins that can be locked in a tilted position in which they are misaligned with a cooperating hole of a cooperating socket. A child safety mechanism (which may be any suitable child safety mechanism) is used to rotate two tabs 41 from a first rotational position, shown in the left hand images, to a second rotational position, shown in the right-hand images. When the tabs 41 are in the first position, the neutral pin 10 and the live pin 12 are pivoted to a tilted position and the plug 1 is in a non-functional state. When the tabs 41 ire in the second position, the neutral pin 10 and the live pin 12 are in a position in which they are aligned with the earth pin 11 and are aligned with cooperating holes of a cooperating socket. This is achieved by the tabs 41 engaging with an inner end of the neutral pin 10 and the live pin 12 in the first position to act to tilt the pins away from the vertical. The neutral pin 10 and the earth pin 12 are biased towards the aligned position such that when the tabs 41 are brought out of engagement with the neutral pin 10 and the earth pin 12 move to the aligned position.

Figure 16 shows a further embodiment of a plug 1 according to the first aspect of the present invention in which the neutral pin 10 can be moved from a first position in which it is misaligned with a cooperating hole of a cooperating socket to a second position in which it is aligned with a cooperating hole of a cooperating socket by means of a child safety mechanism 17. The embodiment of Figure 16 operates in the same manner as the embodiment of Figure 15. The child safety mechanism 17 of the embodiment of Figure 16 comprises a switch 18 and a side activation button 19 in the same manner as the child safety mechanism of Figure 13. In the first position, shown in the left-hand of the large images a tab 41 on the switch 18 acts to tilt the neutral pin 10 to the misaligned position. When the side activation button 19 is pressed the switch 18 can be moved upwards to move the tab 41 out of engagement with the neutral pin 10 to allow it to move back to the aligned position. The neutral pin 10 is biased towards the aligned position and is is pivotally mounted within the plug 1 at an inner end.

In addition, or instead of, tilting the or each pins 10, 11, 12 as shown in the embodiments of Figures 14 to 16, the or each pin 10, 11, 12 may be twisted between a first position in which it is rotationally aligned with a cooperating hole of a cooperating socket and a second position in which it is rotationally misaligned with a cooperating hole of a cooperating socket. This is shown in the embodiment Figure 17 in which the neutral pin 10 is twisted. That is, another method of moving the plug 1 between a functional state and a non-functional state is where one or more of the pins 10, 11 12 were rotational. In a non-functional state one or more of the pins 10, 11, 12 is angled so that it cannot be inserted into a cooperating socket until the child safety mechanism 21 is operated. In the embodiment of Figure 17 the child safety mechanism 21 is a locking disc with meshing gears that turn the pin 10 within a body of the plug 1. This disc may be hidden in a lid or be a lid of the plug 1 so that it is not obviously an operating mechanism. The pin 10 cannot be straightened until the locking disc is rotated to an appropriate position.

In a further alternative embodiment figure 18 shows a three-pin UK plug that consists of a first body part 8 in which the neutral 10 and live pins 12 are mounted and a lid part 4 in which the earth pin 11 is mounted. The lid part 4 is biased away from the first body part 8 by means of a spring 5 mounted between the first body part and the lid part. The plug 1 further comprises a child safety mechanism 24 consisting of a release button 24. In a non-functional state the lid part 4 is held away from the first body part 8 by the action of the spring 5 such that the earth pin 11 is misaligned with the earth hole of a cooperating socket and the plug 1 cannot be fully inserted into the cooperating socket. In order to move the plug 1 from the non-functional state to the functional state the release button 24 must be pressed and the lid part 4 can then be squeezed towards the body part 8 to align the earth pin 11 with the earth hole of the cooperating socket and the plug 1 can then be inserted into the cooperating socket. The lid part 4 cannot be squeezed towards the body part 8 unless and until the release button 24 is pressed. When in the functional state and inserted into a cooperating socket, the cooperating socket acts to hold the earth pin 11 and the lid part 4 in position and maintain the plug in the functional state. When the plug 1 is removed from the cooperating socket the spring 5 will act to move the lid part 4 away from the body part and return the plug to the non-functional state automatically.

The embodiment of Figure 19 is two-pin version of the embodiment of Figure 18. As the plug 1 comprises only a live pin 12 and a neutral pin 10 it is not possible to rely on an earth pin to keep the plug in a non-functional state. Instead it is the live pin 12 that is tiltable between a tilted position in which it is misaligned with the neutral pin 10 and a cooperating hole of a cooperating socket and an un-tilted position in which it is aligned with the neutral pin 10 and a cooperating hole of a cooperating socket. The body of the plug comprises a lid part 4 and a body part 8 that are required to be pressed together to move the plug from a non-functional state to a functional state. As for the embodiment of Figure 18, the plug comprises a release button 24 that must be pressed to allow the lid part 4 to be squeezed towards the body part 8. When the lid part 4 is squeezed towards the body part 8 it pushes against an inner end of the live pin 12 to move it to the aligned position and put the plug in the functional state. The live pin 12 is biased towards the misaligned position by a spring 5 such that removing the plug from a cooperating socket automatically returns the live pin 12 to the misaligned position and returns the plug to the non-functional state.

Figure 20 shows an embodiment of a plug 1 according to a first aspect of the present invention in which a retractable member 25 prevents the plug being fully inserted into a cooperating socket when the plug is in a non-functional state. The plug 1 is a two-pin plug having only a neutral pin 10 and a live pin 12. The retractable member 25 is formed on an upper side of the plug 1 and is connected to a lid part 4 of the plug. In the non-functional state the retractable member protrudes outwards from a pin face of the plug 1 and is biased towards this position by a spring 5 and held in position by a child safety mechanism comprising a locking button 24. In order to move the plug 1 from the non-functional state to the functional state the retractable member 25 must be retracted away from the neutral and live pins 10, 12. This is done by depressing the locking button 24 and then sliding the lid part 4 in a direction away from the neutral and live pins 10, 12. The plug 1 can then be inserted into a cooperating socket. When the plug 1 is removed from a cooperating socket the spring 5 acts to return the retractable member 25 to its protruding position shown in the top images and thereby return the plug 1 to the non-functional state.

Figure 21 is an embodiment of plug according to the first aspect of the present invention in which the live pin 12 can be moved from a misaligned position to an aligned position. When the live pin 12 is in the misaligned position the plug is in the non-functional state. When the live pin 12 is in the aligned position the plug is in the functional state. In the misaligned position the live pin 12 is parallel to, but spaced apart from, the neutral pin 10 by a distance less than the standard spacing between a neutral pin and a live pin. As such, the plug 1 cannot be inserted into a cooperating socket. A body of the plug comprises a lid part 4 and a body part 8 that must be squeezed together to move the live pin 12 away from the neutral pin 10 to put it the standard distance away. The lid part 4 is biased away from the body part 8 by a spring 5. Squeezing the lid part 5 towards the body part 8 acts against the spring 5 to bring the live pin 12 and the neutral pin 10 to the correct spacing to allow the plug 1 to be inserted into a cooperating socket. Whilst in a cooperating socket the socket will act to maintain the spacing of the live and neutral pins 10, 12 and maintain the plug 1 in the functional state. On removal from the cooperating socket the spring 5 will act to move the lid part 4 away from the body part 8 and thereby return the plug 1 to the non-functional state.

Figure 21 is an embodiment of the invention that is a conventional UK three pin plug 1 and has a neutral pin 10, an earth pin 11, and a live pin 12. Th plug 1 has a body part 8 and a lid part 4.

The lid part 4 is biased away from the body part by a spring 5. A retractable member 25 is formed as part of the lid part 4 and extends through an aperture in the body adjacent the earth pin 11. In a non-functional state shown in the upper drawings of Figure 21 the retractable member sits immediately adjacent to the earth pin 11 and thereby prevents the plug 1 being fully inserted into a cooperating socket. The plug 1 further comprises a button 24 that, in the non-functional position, is positioned between the lid part 4 and the body part 8 to prevent the lid part 4 being compressed towards the body part 8. The button 24 is biased towards this position by a spring. Together the lid part 4 and the button 24 form a child safety mechanism. In order to move the plug 1 into a functional state a user must first depress the button 24 and then squeeze the lid part 4 towards the body part 8. This moves the retractable member 25 into a cooperatively shaped and sized slot formed in the earth pin 11. When the retractable member 25 is positioned within the earth pin 11 the plug 1 is in a functional state and can be fully inserted into a cooperating socket. Whilst positioned in a cooperating socket the retractable member 25 will be held in position within the earth pin 11. When the plug 1 is removed from a cooperating socket the spring 5 will move the lid part 4 away from the body part 8, moving the retractable member 25 out of the slot in the earth pin 11, thereby returning the plug 1 to the non-functional state. The button 24 will also be biased outwards and will return to the position between the lid part 4 and the body part 8 thereby preventing the lid part 4 being squeezed towards the body part 8 without depression of the button 24. It is to be understood that in embodiments of the invention a sliding retractable member 24 could additionally or alternatively be provided with the live pin 12 or the neutral pin 10.

In the embodiment of Figure 23 the plug I comprises a retractable pin/shaft 30 that is used to prevent a plug 1 being inserted into a socket when the plug is in a non-functional state. A plug base 31 comprises a pivot pin 30 that is activated using a side lock 32. When the lock 32 is activated, it pivots the pivot pin 30 that is connected via a shaft 33 to turns 90 degree out of the base 31 and protruded from a face of the base 31. The lock 32 can then be lock to secure the pivot pin 30 in the locked position. Whilst the pivot pin 30 is in the locked position the plug 1 cannot be plugged into a cooperating socket. When the lock 32 is unlocked the pin 30 returns within the base 31 and the plug is then in a functional state and can be used with a cooperating socket. The pivot pin 30 can be spring-loaded.

As will be readily appreciated by the person skilled in the art, there are many different designs that fall within the scope of the present invention. Unless otherwise indicated by context the features of any embodiment of the present invention shown in the Figures can be modified and used in combination with the features of any other embodiment. This can be done in any manner apparent to the person skilled in the art. The above description of specific embodiments is not intended to be limiting. Rather, they are illustrative of the concepts of the present invention only. The skilled person will readily appreciate which features of each embodiment can be combined with other embodiments. The scope of the invention is defined in the claims.

Claims

CLAIMS1 An electrical plug for connection to an electrical cable and cooperating socket comprising: a body; a live pin extending from the body; a neutral pin extending from the body; a live terminal for connection to a live wire located within the body; a neutral terminal for connection to a neutral wire located within the body; and a child safety mechanism; wherein the child safety mechanism can be operated to move the plug from a non-functional state in which the plug can't be fully inserted into the cooperating socket to a functional state in which the plug can be fully inserted into the cooperating socket; and in the non-functional state one or more of the pins is misaligned with a cooperative hole in the cooperating socket blocking the plug from being inserted into the socket and in the functional state the one or more of the pins is moved to align with the cooperative hole in the cooperating socket allowing the plug to be inserted into the socket; and/or the plug further comprises a retractable member and in the non-functional state the retractable member is positioned in a first position in which it extends from the body to block the plug being fully inserted into the cooperating socket and in the functional state the retractable member is positioned a second position in or on the body of the plug a second position such that the plug can be fully inserted into the cooperating socket.
2 An electrical plug according to claim 1, further comprising a biasing means, wherein the biasing means biases the plug towards the non-functional state such that when the child safety mechanism is not being operated by a user and the plug is not fully positioned within a cooperating socket the biasing means maintains the plug in, or moves the plug to, the non-functional state
3 An electrical plug for connection to an electrical cable and cooperating socket comprising: a body; a live pin extending from the body; a neutral pin extending from the body, a live terminal for connection to a live wire located within the body; a neutral terminal for connection to a neutral wire located within the body; a child safety mechanism; and biasing means; wherein the child safety mechanism can be operated to move the plug from a non-functional state to a functional state, and wherein the biasing means biases the plug towards the non-functional state such that when the child safety mechanism is not being operated by a user and the plug is not fully positioned within a cooperating socket the biasing means maintains the plug in, Or moves the plug to, the non-functional state.
4 An electrical plug according to any preceding claim, wherein the child safety mechanism comprises a switch that is required to be depressed to operate the child safety mechanism
5. An electrical plug according to any preceding claim, wherein the child safety mechanism comprises a hidden release button
6 An electrical plug according to any preceding claim, wherein the child safety mechanism comprises a twist mechanism that is required to be depressed in order to be twisted.
7. An electrical plug according to any preceding claim, wherein the child safety mechanism comprises a twist mechanism that is formed as part of the plug body.
8 An electrical plug according to any preceding claim, wherein the child safety mechanism is formed such that its operation requires a sequence of mechanical processes to be carried out in the correct order.
9. An electrical plug according to any preceding claim, wherein the child safety mechanism comprises a combination lock.
10 An electrical plug according to claim 9, wherein opening the combination lock moves the plug from the non-functional state to the functional state.
11 An electrical plug according to any preceding claim, wherein the child safety mechanism comprises a removable magnetic key and a magnetic actuator located within the body
12. An electrical plug according to any preceding claim, wherein the child safety mechanism act magnetically to put the plug in a functional state.
13. An electrical plug according to any preceding claim, further comprising an earth pin extending from the body.
14. An electrical plug according to claim 13, further comprising an earth terminal located within the body for connection to an earth wire
15. An electrical plug according to any preceding claim further comprising a lock that allows the plug to be locked in the non-functional state.
16. An electrical plug according to any preceding claim, further comprising: a first openable connection either between the live terminal and an inner end of the live pin located within the body or between the neutral terminal and an inner end of the neutral pin located within the body; and an actuation means for closing the first openable connection; wherein in the non-functional state the first openable connections is held in an opened position and operating the child safety mechanism operates the actuation means to close the first openable connection.
17. An electrical plug according to claim 16, comprising: a first openable connection between the live terminal and an inner end of the live pin located within the body; and a second openable connection between the neutral terminal and an inner end of the neutral pin located within the body; wherein when operated the actuation means acts to close the first and second openable connections; and in the non-functional state of the electrical plug the first and second openable connections are held in an opened position.