Adapters for electrical plugs

Abstract: The present invention provides an adapter (1) for retaining a moulded plug (51) within itself. Preferably, the adapter (1) comprises: an upper (5) and a lower (3) portion; a plurality of pins (15, 17, 19) which extend from the lower portion (3) for connecting the adapter (1) to the mains; means (14, 50) for securing a moulded plug (51) having at least two pins (53, 55) within the adapter (1); means (21, 23, 29) for receiving in electrical contact respective ones of the plug pins (53, 55), each receiving means being electrically connected to a respective one of the mains pins; (15, 17, 19) and means for removably securing the upper portion to the lower portion.

Description: This invention relates to adapters for moulded electrical plugs. These adapters enable moulded plugs having a pin arrangement incompatible with that of the mains socket, such as 2 pin shaver-plugs, to be connected to the mains. A known adapter for connecting a 2 pin shaver plug to a three pin mains socket comprises a lower and an upper portion. These portions are removably secured to each other. Extending out from the lower portion in a standard arrangement are the neutral, earth and live pins. The upper portion has two slots through which the pins of the incompatible moulded plug can be pushed. The internal surfaces of the slots are metallic so that when the pins of the incompatible plug are inserted into the slots, they are electrically connected to the metallic portions of the slots. The metallic portions are in turn electrically connected to the live and neutral pins respectively of the lower portion. When the incompatible plug is required for use, its pins are pushed into the slots of the adapter. The adapter, with the incompatible plug mounted onto it, is then simply pushed into a standard household three pin socket. The incompatible moulded plug is now electrically connected to the mains. However, problems are associated with such adapters. For example, often the moulded plug can become dislodged from the adapter, thus losing the electrical contact. Also, some moulded 2 pin plugs do not have sufficient insulation about their pins, and so care has to be taken when removing the plug from the adapter while connected to the mains. US patent no. 4605273 discloses a twist-lock to parallel blade adapter consisting of a cylindrical lower housing section which carries the twist-lock blade terminals on its lower, exterior surface and parallel blade receptacles on its interior surface. A parallel blade power plug may be inserted in these receptacles and a second housing section is then attached by screws to envelop the power plug and to clamp the plug cable between the two housing sections at a distance from the plug itself. The present invention provides an adapter for a moulded plug which can safely retain the plug. This is achieved by providing an adapter for retaining a moulded plug within itself. According to the present invention there is provided an adapter for the retention of a moulded plug having a plug body, at least two pins and a cable, within itself comprising: an upper and a lower portion; a plurality of pins which extend from the lower portion for connecting the adapter to the mains; means for securing the moulded plug within the adapter; means for receiving in electrical contact respective ones of the plug pins, each receiving means being electrically connected to a respective one of the mains pins; and means for removably securing the upper portion to the lower portion, characterized in that the means for securing the moulded plug within the adapter comprises means integral with at least one of the upper and lower portions which is adapted to abut the plug body at a position remote from the cable, to prevent the plug from being dislodged from its connection with the receiving means by movement in a direction towards the cable. Preferably the lower portion comprises a platform having formed on its periphery an upstanding wall, said platform having a plurality of holes for receiving and supporting the mains pins; and the upper portion comprises a platform having formed on its periphery a depending wall. A first alternative securing means for the moulded plug comprises an appropriately shaped recess formed by the upper and/or lower portions for receiving all or part of the plug body within the adapter. A second alternative securing means comprises a plurality of ribs or cones formed on the lower portion, the upper portion or both, which tightly abut the plug when the upper and lower portions are secured together. A third alternative securing means comprises a series of indentations formed in the upper and/or lower portions of the adapter for receiving the pins. A fourth alternative securing means comprises a sleeve which fits around part or all of the plug body. The sleeve may have a plurality of ribs for co-operation with suitable grooves formed in the upper and/or lower portions. A fifth alternative securing means comprises resilient clips located in the adapter for bearing on the body of the plug when located in the adapter. The above-mentioned securing means may be used alone or in any combination. Preferably, the means for receiving the plug pins comprise metallic spring clips or sleeves of the appropriate size. The clips or sleeves may be mounted on the lower portion or directly onto the mains pins. Where the means for receiving the plug pins are not mounted directly on the mains pins, it will be necessary to provide electrical connections from the pin receiving means to the mains pins. Preferably, the electrical connections comprise electrically conductive strips. Preferably, a fuse arrangement is provided within the lower portion. Advantageously, the fuse is in series with one of the electrical strips. Suitable means for securing the upper portion to the lower portion may comprise at least one standard screw and thread arrangement. Alternatively, the upper portion may be hinged to the lower portion, the two portions being interlocked when in a closed position by means of a cam locking mechanism. In another alternative, the securing means may include means for allowing the upper portion to slide over, and be secured to the lower portion and to be locked in place. A preferred adapter has the standard 3 pin arrangement i.e. a neutral pin, an earth pin and a live pin for connection to the mains, and has three clips mounted within the lower portion for receiving moulded plugs having either 2 pins or 3 pins. Thus the present invention provides an adapter that can retain moulded plugs, such as 2 pin or 3 pin moulded plugs, within the body of the adapter itself. As the moulded plug is retained within the adapter it cannot become free while in use. A specific embodiment of an adapter according to the present invention is now described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a plan view of the lower portion of the adapter; Figure 2 is a sectional view of the adapter showing the lower and upper portions; Figure 3 is a plan view of the lower portion of the adapter with a moulded 2 pin plug located therein; and Figure 4 is a sectional view of the adapter with a moulded 2 pin plug secured therein. Referring now to the drawings, there is shown an adapter 1 comprising a lower portion 3 and an upper portion 5. The lower portion comprises a generally square, planar platform 7 having formed on its periphery an upwardly extending wall 9. On one side of the wall 9 there is formed a recess 11, and on the opposite side there is formed a series of small indentations 13. The lower portion 3 also has a plurality of moulded ribs 14 on the upper surface of the platform 7. Three holes (not shown) are formed within the platform 7. In each hole an electrical pin 15, 17 and 19 is located in such a fashion that one end of each pin is secured just above the platform 7 as shown in Figures 2 and 4, the remainder of the pin extending below the platform. The pins 15, 17 and 19 are respectively the neutral, earth and live pins and are arranged so that the adapter can be plugged into a conventional mains socket. Two electrically conductive clips 21 and 23 are mounted, by means of electrically conductive supports 25 and 27 respectively, on platform 7. A third electrically conductive clip 29 is mounted, by means of an electrically conductive support 31, directly on the earth pin 17. Two further electrically conductive clips 33 and 35 are mounted on platform 7. These sleeves 33 and 35 provide support for a fuse 37, as shown in Figures 1 and 3. The clip 21 is electrically connected to the neutral pin 15 by means of an electrically conductive strip 39. The clip 23 is electrically connected to the first fuse clip 33 by means of a electrically conductive strip 41, and the second fuse clip 35 is electrically connected to the live pin 19 by means of an electrically conductive strip 43. The upper portion 5 also comprises a generally square, planar platform 45. On the periphery of the platform 45 is formed a depending wall 47. On one side of the wall 47 there is formed a recess 49 which in use is aligned with the recess 11 in the lower portion. A plurality of ribs 50 are moulded onto the lower surface of the upper portion 5. The adapter 1 is also provided with suitable securing means (not shown) such as one or more screw and thread arrangements for removably securing the lower portion 3 to the upper portion 5 in a fashion as shown generally in Figures 2 and 4. When required for use, the upper portion 5 is removed from the lower portion 3. A moulded two pin plug 51, such as a shaver plug, is then placed within the lower portion 3, in such a fashion that the first electrical pin 53 of the moulded plug 51 is located within clip 21, and the second electrical pin of the moulded plug 51 is located within clip 23. The moulded plug 51 is then pushed in a direction away from the recess 11, until pins 53 and 55 rest in the small indentations 13. In this arrangement the other end of the plug 51 and the electrical cable 57, joined to the moulded plug 51, protrude from the lower portion 3 through the recess 11. A fuse 37, if necessary, is then mounted between the first and second fuse clips 33 and 35. The upper body 5 is then secured to the lower body 3, in such a fashion that the recess 49 fits over the rear portion of the plug 51 and the cable 57. Securing the upper portion to the lower portion causes the ribs 14 and 50 to press into the plug body 52. The plug 51 is now secure within the adapter 1 as any form of relative movement is prevented by recess 11, indentations 13 and ribs 14 and 50. The adapter, with the 2 pin moulded plug retained within it, is then inserted into a standard household 3 pin plug socket. The above example first describes the insertion of a 2 pin plug into the adapter 1. In this arrangement the earth clip 29 is redundant. However, the provision of this clip makes the adapter 1 suitable also for the insertion of a moulded 3 pin plug having an earth. Of course, other suitable earthing means can be provided to be compatible with that of the moulded plug to be fitted, such as a scraping earth (not shown) commonly used in countries such as Germany.

Claims: An adapter (1) for the retention of a moulded plug (51) having a plug body (52), at least two pins (53,55) and a cable (57), within itself comprising: an upper (5) and a lower (3) portion; a plurality of pins (15, 17, 19) which extend from the lower portion (3) for connecting the adapter (1) to the mains; means (14, 50) for securing the moulded plug (51) within the adapter (1); means (21, 23, 29) for receiving in electrical contact respective ones of the plug pins (53, 55), each receiving means being electrically connected to a respective one of the mains pins (15, 17, 19); and means for removably securing the upper portion (5) to the lower portion (3), characterized in that the means for securing the moulded plug (51) within the adapter (1) comprises means integral with at least one of the upper (5) and lower (3) portions which is adapted to abut the plug body (52) at a position remote from the cable (57), to prevent the plug (51) from being dislodged from its connection with the receiving means (21, 23, 29) by movement in a direction towards the cable (57). The adapter of claim 1, wherein the lower portion comprises a platform (7) having formed on its periphery an upstanding wall (9), said platform (7) having a plurality of holes for receiving and supporting the mains pins (15, 17, 19); and the upper portion (5) comprises a platform (45) having formed on its periphery a depending wall (47). The adapter of claim 1 or claim 2, wherein the securing means comprises an appropriately shaped recess formed by the upper and/or lower portions (3, 5) for receiving all or part of the plug body (52) within the adapter (1). The adapter of claim 1 or claim 2, wherein the securing means comprises a plurality of ribs or cones (14,50) formed on the lower portion (3), the upper portion (5) or both, which tightly abut the plug when the upper and lower portions are secured together. The adapter of claim 1 or claim 2, including a series of indentations (13) formed in the upper and/or lower portions (5,3) of the adapter for receiving the pins. The adapter of claim 1 or claim 2, wherein the securing means comprises a sleeve which fits around part or all of the plug body. The adapter of claim 1 or claim 2, wherein the securing means comprises resilient clips located in the adapter for bearing on the body of the plug when located in the adapter. The adapter of any one of claims 1 to 7, wherein the means (21, 23, 29) for receiving the plug pins comprise metallic spring clips or sleeves of the appropriate size. The adapter of any one of claims 1 to 8, wherein a fuse arrangement (33,35,37) is provided within the lower portion.

Inventors: HOSSACK SIMON, HOSSACK, SIMON
Applicants: HOSSACK SIMON, HOSSACK, SIMON
Application year: 1989
Main classification: H01R31
IPC codes: H01R31