Rotatable plug and power supply device having the rotatable plug

A rotatable plug includes a casing unit having a first casing part and a second casing part with a pair of receiving spaces, a pair of conductive terminals respectively having conductive sections, and a rotatable unit including a pivot shaft, a pair of conductive prongs connected transversely to the pivot shaft, and a pair of conductive protrusions protruding out from the pivot shaft. The rotatable unit is rotatable relative to the casing unit between non-use and use positions, where the conductive prongs are accommodated in and extend out of the receiving spaces, respectively. Each conductive protrusion has at least two points of contact with the conductive section of a respective conductive terminal.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Chinese Patent Application No. 201220083223.5, filed on Mar. 7, 2012.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a rotatable plug, more particularly to a rotatable plug that can be stored conveniently when not in use and a power supply device having the rotatable plug.

2. Description of the Related Art

A plug of a conventional power supply device includes a plug body and two conductive terminals protruding outwardly from the plug body. When the power supply device is not in use, because the conductive terminals protrude from the plug body, they are likely to be hit by an external force that may result in the bending and even breakage thereof. Further, it is difficult to store the conventional power supply device. Therefore, devices with rotatable plugs have been currently developed to resolve the aforesaid issues.

Referring toFIGS. 1,2and3, a conventional power supply device having a rotatable plug includes a housing11, a rotatable plug12and a fixing element13. The housing11includes a housing body111, a holding seat112formed on an end of the housing body111, and a receiving hole113extending through the holding seat112.

The rotatable plug12includes a rotating support body121inserted into the receiving hole113, two conductive prongs122fixed on the rotating support body121, two metal pivot studs123protruding outwardly and respectively from two opposite ends of the rotating support body121, two conductive plates124respectively pivoted to the pivot studs123, and three projections125,126projecting from the rotating support body121opposite to the conductive prongs122. Two conductive wires (not shown) may be respectively inserted through the conductive plates124to connect electrically with a circuit board (not shown).

The fixing element13fixes the rotatable plug12to the holding seat112, and includes a fixing main body131, two stop bosses132disposed on one side of the fixing main body131and extending towards the housing body111, a stepped portion formed in the middle of the fixing main body131and having a first part133and a second part134, and two spaced-apart slots135formed in the fixing main body131. The conductive plates124extend respectively through the slots135.

The housing11(seeFIG. 1) is removed inFIGS. 2 and 3to facilitate description of the rotating mechanism of the rotatable plug12. With reference toFIG. 2, when the conductive prongs122of the rotatable plug12are in a use or extended position, the projection125abuts against the first and second parts133,134of the stepped portion and is positioned thereat. When a force is applied on the conductive prongs122to rotate the same in a direction of an arrow (R1), through the resiliency of the stepped portion, the projection125can slide over the second part134. As such, the conductive prongs122can drive the rotating support body121to rotate relative to the holding seat (seeFIG. 1). As shown inFIG. 3, the projection126is blocked by the stop boss132and is positioned thereat. At this state, the conductive prongs122are disposed in a non-use or folded position. By applying a force again on the conductive prongs122to rotate the same in a direction of an arrow (R2), the conductive prongs122are restored to their use position.

However, the above-mentioned device is not modular so that a new mold must be opened in respond to different sizes of housing11. Moreover, three projections125,126are needed to position the rotatable plug12in the use and non-use positions. Finally, because the rotatable plug12is connected to the fixing element13through insertion of the conductive plates124into the slots135, the conductive plates124are likely to separate from the fixing element13due to frequent use which may cause poor electrical contact.

SUMMARY OF THE INVENTION

Therefore, an object of the present invention is to provide a rotatable plug that can provide a stable and reliable electrical connection.

Another object of the present invention is to provide a power supply device having a rotatable plug that can provide a stable and reliable electrical connection.

According to one aspect of this invention, a rotatable plug comprises a casing unit, a pair of conductive terminals and a rotatable unit.

The casing unit includes a first casing part, and a second casing part connected to the first casing part and formed with a pair of receiving spaces. The conductive terminals are insert molded into the first casing part. Each of the conductive terminals has a conductive section. The rotatable unit includes a pivot shaft, a pair of conductive prongs connected to and extending transversely from the pivot shaft, and a pair of conductive protrusions protruding out from the pivot shaft. The rotatable unit is disposed in the casing unit and is rotatable relative to the casing unit between a non-use and folded position, where the conductive prongs are respectively accommodated in the receiving spaces, and a use or extended position, where the conductive prongs respectively extend out of the receiving spaces. Each of the conductive protrusions is disposed on and has at least two points of contact with the conductive section of a respective one of the conductive terminals when the rotatable unit is in the use position.

Preferably, the conductive section of each of the conductive terminals has a depressed contact surface.

Each of the conductive protrusions has the at least two points of contact with the depressed contact surface.

Preferably, the first casing part includes a pair of first support posts each having a slotted surface. Each of the conductive terminals further has a conductive end protruding from the slotted surface. The pivot shaft includes two outer conductive shaft sections respectively connected to the prongs, and an insulated middle shaft section between the outer conductive shaft sections. The outer conductive shaft sections are respectively in contact with the conductive ends of the conductive terminals when the rotatable unit is in the use and non-use positions.

Preferably, the first casing part includes a pair of second support posts supporting the pivot shaft.

Preferably, the first casing part has a positioning portion formed with a positioning groove. The rotatable unit further includes a first protuberance and a second protuberance protruding from the pivot shaft between the conductive protrusions and perpendicular to each other. The first protuberance is positioned in the positioning groove when in the non-use position, and the second protuberance is positioned in the positioning groove when in the use position.

Preferably, each of the conductive terminals further has a conductive extension disposed externally of the casing unit.

Preferably, the conductive extensions of the conductive terminals have different lengths.

According to another aspect of this invention, a power supply device comprises a housing unit, a circuit unit and a rotatable plug.

The housing unit includes a first housing element having two parallel slots, and a second housing element connected to and cooperating with the first housing element to define a chamber. The circuit unit is disposed in the chamber. The rotatable plug is disposed in the chamber and includes a casing unit, a pair of conductive terminals and a rotatable unit.

The casing unit includes a first casing part, and a second casing part connected to the first casing part and formed with a pair of receiving spaces. The conductive terminals are insert molded into the first casing part and are connected electrically to the circuit unit. Each of the conductive terminals has a conductive section. The rotatable unit includes a pivot shaft, a pair of conductive prongs connected transversely to the pivot shaft, and a pair of conductive protrusions protruding out from the pivot shaft. The rotatable unit is disposed in the casing unit and is rotatable relative to the casing unit between a non-use or folded position, where the conductive prongs are respectively accommodated in the receiving spaces and the slots, and a use or extended position, where the conductive prongs respectively extend out of the receiving spaces and the slots. Each of the conductive protrusions is disposed on and has at least two points of contact with the conductive section of a respective one of the conductive terminals when the rotatable unit is in the use position.

Preferably, each of the receiving spaces includes a cover-receiving section, and a prong-receiving section communicating spatially with said cover-receiving section. Each of the slots has a length greater than or equal to a length of a corresponding receiving space and a width greater than or equal to a width of a corresponding prong-receiving section.

The effect of this invention resides in that because each arcuate conductive protrusion has at least two points of contact with the depressed contact surface of the corresponding conductive section, the rotatable plug of the present invention has a good effect of conduction. Further, the conductive terminals are insert molded into the first casing part so that only the conductive sections and the conductive ends thereof protrude inwardly from the inner surface of the first casing part, the fixing method thereof is stable and the electrical connection process thereof is reliable. Finally, with only the first and second protuberances cooperating alternately with the positioning groove to position the rotatable unit in the non-use and use positions, and with the connection of the first and second casing parts, the present invention can be modular.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The above-mentioned and other technical contents, features, and effects of this invention will be clearly presented from the following detailed description of a preferred embodiment in coordination with the reference drawings.

Referring toFIGS. 4 to 20, a power supply device according to the preferred embodiment of the present invention comprises a housing unit5, a circuit unit, and a rotatable plug200.

The housing unit5includes a first housing element51and a second housing element52connected to and cooperating with the first housing element51to define a chamber53(seeFIG. 18). The first housing element51has a base wall511, a surrounding wall512extending transversely from the base wall511, and two parallel slots513formed in the surrounding wall512.

As shown inFIGS. 18 and 19, the circuit unit6and the rotatable plug200are disposed in the chamber53.

With reference toFIGS. 4 and 5, the rotatable plug200includes a casing unit2, a pair of conductive terminals3and a rotatable unit4. The casing unit2includes a first casing part21and a second casing part22connected to the first casing part21. The first casing part21includes a plate-shaped body211, a pair of first support posts212extending inwardly and respectively from two opposite sides of the plate-shaped body211, a pair of second support posts213disposed between the first support posts212, and a positioning portion214extending inwardly from the plate-shaped body211and disposed between the second support posts213. Specifically, each first support post212is hollow, extends from an inner surface of the plate-shaped body211at the two opposite sides thereof, and has an arcuate slotted surface216distal from the plate-shaped body211. The positioning portion214is formed with a central positioning groove217.

The conductive terminals3are insert molded into the first casing part21and are connected electrically to the circuit unit6. Each of the conductive terminals3has a conductive section31disposed between one of the first support posts212and a corresponding second support post213, a conductive end32protruding from the slotted surface216of a respective first support post212, and a conductive extension33opposite to the conductive end32and extending from an outer surface of the plate-shaped body211. The conductive section31has a depressed contact surface311. The conductive end32is arcuate.

The configuration of each conductive terminal3before being insert molded into the first casing part21is as shown inFIG. 6. The conductive section31of each conductive terminal3is substantially U-shaped, and includes a bight portion having the depressed contact surface311, and two arms extending transversely from two opposite ends of the bight portion. Each conductive terminal3further has a first conductive plate34and a second conductive plate35respectively connected to and extending horizontally from the two opposite arms of the conductive section31, and a third conductive plate36that is substantially J-shaped and that has one end connected to the bight portion and another end having the arcuate conductive end32. The conductive extension33extends from one end of the first conductive plate34that is distal from the conductive section31. To easily distinguish the positive and negative polarities of the conductive terminals3, the two conductive extensions33have different lengths. The conductive extension33has a through hole37. Two conductive wires (not shown) can be soldered to the through holes37in the conductive extensions33of the conductive terminals3to connect electrically with the conductive extensions33.

With reference toFIGS. 4 and 7, the second casing part22includes a casing body221, and a pair of parallel receiving spaces222formed in the casing body221. Each of the receiving spaces222includes a cover-receiving section223, and a prong-receiving section224communicating spatially with the cover-receiving section223.

With reference toFIGS. 8 and 9, the rotatable unit4includes a pivot shaft41, and a pair of parallel conductive prongs42connected transversely to the pivot shaft41. The pivot shaft41includes two outer conductive shaft sections43respectively connected to the prongs42, an insulated middle shaft section411between the outer conductive shaft sections43, and two cover sections412disposed respectively on two opposite ends of the middle shaft section411. Each of the cover sections412covers a junction of the outer conductive shaft sections43and a respective prong42. A first protuberance45and a second protuberance46protrude outwardly from the middle shaft section411, are perpendicular to each other, and are made of insulated materials. A pair of conductive protrusions44respectively protrudes out from the cover sections412of the pivot shaft41.

In actual applications, the rotatable unit4has the prongs42, which are made of metal, insert molded to the pivot shaft41such that the cover sections412of the pivot shaft41cover partially the prongs42. Before the prongs42are insert molded to the pivot shaft41, the configuration thereof is as shown inFIG. 9. Each of the prongs42includes an elongated insert section421, and a connecting section422opposite to the insert section421. The conductive protrusions44protrude outwardly and respectively from the connecting sections422of the prongs42, and are disposed externally of the cover sections412, respectively.

With reference toFIGS. 4,5,8and10, to assemble the rotatable plug of the present invention, the rotatable unit4is first connected to the second casing part22by inserting the cover sections412of the pivot shaft41into the corresponding cover-receiving sections223of the receiving spaces222and the prongs42into the corresponding prong-receiving sections224of the receiving spaces222. At this time, a portion of the insert section421of each prong42extends out of the corresponding prong-receiving section224, and the outer conductive shaft sections43are exposed from lateral sides of the casing body221(only one is visible inFIG. 10). The second casing part22and the rotatable unit4are then integrated with the first casing part21such that the middle shaft section411of the pivot shaft41abuts against the second support posts213and the outer conductive shaft sections43abut against and electrically coupled to the conductive ends32of the conductive terminals3. Finally, because the first casing part21further includes a plurality of welding spots218arranged on a periphery of the inner surface of the plate-shaped body211, the first and second casing parts21,22are integrated together using an ultrasonic welding process.

With reference toFIGS. 10 to 13, the rotatable unit4is disposed in the casing unit2and is rotatable relative to the same between a non-use or folded position and a use or extended position. The second casing part22is removed inFIGS. 11 and 13to facilitate description of the positioning mechanism of the rotatable unit4during the non-use and use positions.

Referring toFIGS. 10 and 11, when the rotatable unit4is in the non-use position, the insert sections421of the prongs42are respectively accommodated in the prong-receiving sections224with the portions thereof protruding from the corresponding prong-receiving sections224, and the first protuberance45is positioned in the positioning groove217(seeFIG. 5). When the insert sections421of the prongs42are rotated in the direction of an arrow (I) to extend out of the prong-receiving sections224, the second protuberance46is positioned in the positioning groove217, as shown inFIGS. 12 to 14. As shown inFIG. 15, the conductive protrusion44is disposed on the conductive section31. Since the conductive section31has the depressed contact surface311and the conductive protrusion44is arcuate, the conductive protrusion44has at least two points of contact with the conductive section31so that it has a large area of contact with the same to thereby enhance the effect of conduction. The conductive section31is not limited to having the depressed contact surface311. As shown inFIG. 16, the conductive section31may have a substantially V-shaped contact surface311′, so that the conductive protrusion44has two points of contact with the conductive section31. As shown inFIG. 12, when the insert sections421of the prongs42are rotated in the direction of an arrow (II), the rotatable unit4is rotated back to the non-use position shown inFIGS. 10 and 11.

As shown inFIG. 17, the outer conductive shaft section43is in constant contact with the conductive end32whether the rotatable unit4is in the non-use or use position. Hence, in the use position, as shown inFIG. 13, the conductive terminals3and the rotatable unit4are electrically coupled to each other through the aforesaid two methods, so that reliability of electrical connection can be enhanced. Further, referring once again toFIGS. 4,8and10, the cover-receiving section223of each receiving space222has a width (W1), the prong-receiving section224of each receiving space222has a width (W2), each cover section412of the pivot shaft41has a thickness (T1), and each prong42has a thickness (T2). In the non-use position, because the width (W2) of the prong-receiving section224is smaller than the width (W1) of the cover-receiving section223, and the thickness (T2) of each prong42is smaller than the thickness (T2) of each cover section412, the insert sections421of the prongs42can be stably received in the prong-receiving sections224of the second casing part22.

Referring back toFIGS. 11,12and13, more particularly, because the conductive sections31have elasticity, when the conductive sections31are in contact with or separated from the conductive protrusions44, the wearing thereof caused by repeated rotation between the non-use and use positions can be reduced. Further, by using the ultrasonic welding method to integrate the first and second casing parts21,22, the separation of the first and second casing parts21,22due to the frequent switching between the non-use and use positions can be prevented.

With reference toFIGS. 18 and 19, in combination withFIG. 4, each of the slots513in the housing unit5has a length slightly longer than or equal to that of the corresponding receiving space222, and a width larger than or equal to that of the corresponding prong-receiving section224. The outer surface of the casing body221of the second casing part22abuts against inner surfaces of the base wall511and the surrounding wall512and is proximate to the two slots513, so that the cover-receiving sections223and the prong-receiving sections224of the receiving spaces222are in spatial communication with the slots513to facilitate rotation of the insert sections421of the prongs42in and out of the housing unit5.

Referring again toFIGS. 18,19and20, the rotatable unit4is similarly rotatable relative to the casing unit2between the non-use or folded position and the use or extended position as described above. The difference resides in that the insert sections421of the prongs42of the rotatable unit4can be rotatably received in the respective slots513of the first housing element51.

In the non-use position, as shown inFIG. 18, the insert sections421of the prongs42are accommodated in the slots513. When the insert sections421are rotated in the direction of the arrow (I), as shown inFIGS. 19 and 20, the insert sections421are moved to extend out of the respective slots513. When the insert sections421are rotated in the direction of the arrow (II), the insert sections421are moved back to the position shown inFIG. 18.

In summary, because each arcuate conductive protrusion44has at least two points of contact with the depressed contact surface311of the corresponding conductive section31, the rotatable plug of the present invention has a good effect of conduction. Further, the conductive terminals3are insert molded into the first casing part21so that only the conductive sections31and the conductive ends32thereof protrude inwardly from the inner surface of the first casing part21, the fixing method thereof is stable and the electrical connection thereof is reliable. Finally, with only the first and second protuberances45,46cooperating alternately with the positioning groove217to position the rotatable unit4in the non-use and use positions, and through the connection of the first and second casing parts21,22, the present invention can be modular. Hence, the objects of the present invention can be realized.