WO2004075360A1

WO2004075360A1 - Contact plug with means for facilitating disengagement from a socket

Info

Publication number: WO2004075360A1
Application number: PCT/DK2004/000093
Authority: WO
Inventors: Tom Christensen
Original assignee: Tom Christensen
Priority date: 2003-02-18
Filing date: 2004-02-10
Publication date: 2004-09-02
Also published as: EP1599922A1

Abstract

A contact plug (1;20;32) mounted on an electric wire (7) and comprising a casing (4;21;33), at least two contact pins (5,6;22,23) projecting from the casing (4;21;33) for detachably engaging a complementarily shaped female connector (2), a dismounting device (13;24;36) having a first (14;26;38) - and a second end part (15;27;37) and mounted in the casing (4;21;33) displaceably between a first position in which the second end part (15;27;37) is at least mainly located in the casing (4;21;33) and a second position in which the second end part (15;27;37) is pushed out of the casing (4;21;33) to the same side as the contact pins (5,6;22,23), an actuator (9;25;34) for displacing the dismounting device (13;24;35) from the first to the second position by means of an application of force on the first end part (14;26;36) of the dismounting device (13;24;35), in said second position at least the greater part of the actuator (9;25;34) is received in a hollowing (8;19;41) in the casing (4;21) and the dismounting device (13;24;35) is extending a distance into the hollowing (8;19;41) in the first position of the dismounting device (13;24;35). The contact plug (1;20;32) is easy to disengage with little strength without pulling the wire (7).

Description

Contact plug with means for facilitating disengagement from a socket

The invention relates to a contact plug of the kind which is adapted to be mounted on e.g. an electric wire and which comprises a casing, at least two contact pins projecting from the casing for detachably engaging complementarily shaped female connectors, a dismounting device having first and second end parts and mounted in the casing displaceably between a first position in which the second end part is at least mainly received in the casing, and a second position in which the second end part is pushed out of the casing on the same side as the contact pins, and an actuator for displacing the dismounting device from the first to the second position by means of application of force on the first end part of the dismounting device.

To meet national and international standards many electric contact plugs today have round and relatively thick contact pins. Therefore, the pins often fit very tightly in especially older installations, which are often designed for insertion of flat or thin contact pins.

In many cases, it can therefore be difficult to pull a contact plug out of e.g. an electric outlet. The electric outlet is worn and gradually looses its hold in the brickwork and the electric connections. Loose electric outlets increase the risk of short circuits and electric shocks.

Persons having rheumatism in the hands or persons with hands of reduced strength for other reasons find it very difficult to get hold of e.g. a contact plug and pull it out of a socket or electric outlet. Contact plugs on especially smaller domestic appliances, such as e.g. a vacuum cleaner or an iron, must be put in and pulled out of a socket or electric outlet often. They are often pulled out by pulling the electric wire with consequent risk of overloading or damaging the contact plug, socket or electric outlet and the connecting cables to these.

A tightly coupled electrical connection between such male and female connections is furthermore difficult to disconnect by means of only one hand.

Attempts have been made to overcome these disadvantages by the contact plug known from the German Patent Publication DE 198 32 648 Al . Said contact plug is arranged with an actuator firmly connected to a dismounting device. The actuator of this known contact plug will project from the casing of the contact plug in all situations. If the wire with contact plug is rolled or wound up till the next connection, the wire risks getting tangled and getting hold of the actuator. If the user is unaware of this, the firm connection between the actuator and the dismounting device risks being broken. Every time the contact plug is to be pulled free of a socket or electric outlet, the firm connection is subjected to a heavy load with consequent risk of breaking.

A contact plug having a T-shaped dismounting device and a pivotally mounted actuator is known from the German Patent Publication DE 195 13 170 Al . The dismounting device has a pressure plate for pushing the contact plug free of a socket in which the contact plug is mounted. The force with which the actuator must be loaded is distributed across the entire pressure plate, and a relatively large force must therefore be used to push free the contact plug. Furthermore, the pressure plate occupies a part of the space between the contact plug and the socket or electric outlet in use, and the contact plug must therefore be shaped with especially long contact pins to make sure that the necessary electrical contact is present. The contact pins are extending through holes in the pressure plate, and impurities deposited between the pressure plate, the contact pins and the casing of the contact plug will prevent the dismounting device from returning to the contact plug when this contact plug is mounted in electrical connection with the socket.

The above disadvantages are attempted overcome by means of the contact plug according to the present invention.

According to a first aspect, the present invention provides a contact plug which can be pulled free of a female connector by means of little strength.

In a second aspect according to the present invention, a contact plug is provided, which can be pulled free of a female connector without damaging the connectors or the electric installation.

The novel and unique feature by means of which this is achieved according to the invention is a hollowing made in the casing on the opposite side of the contact pins for at least partly receiving the actuator in the second position of the dismounting device and having a depth allowing the first end part of the dismounting device to extend into the hollowing in the first position of the dismounting device.

The distance which the dismounting device is extending into the hollowing will advantageously lift the actuator sufficiently free of the hollowing so that the actuator can be operated manually when the contact plug is to be disconnected from the female connector.

The contact plug and the female connector can be disengaged in an especially easy manner if the first part of the dismounting device is extending into the hollowing in the first position by a length corresponding to or longer than the depth of the hollowing. In a first embodiment of the present invention, the hollowing can be a groove extending transversely of the dismounting device.

However, this embodiment is not meant to limit the invention, as the hollowing also can be made lengthwise of the dismounting device.

An actuator made as an arm with a first end pivotally mounted in the groove and a second end located outside the groove in the first position of the dismounting device can advantageously be completely or partly received in the groove in the second position of the dismounting device in a simple manner .

Advantageously, the arm can, at a first end, be pivotally suspended in the hollowing in a plane intersecting a plane through the dismounting device parallel to the longitudinal axis of this dismounting device so that the arm will hit the dismounting device when it is pivoted into the groove and affect this dismounting device with a sufficiently large force to overcome the engagement between the connectors .

The second end of the arm will be free of the groove in the first position of the dismounting device and can be manually affected by means of e.g. a finger so that a co pressive force can be transmitted to the point of application between the arm and the dismounting device by an exchange of force.

The greater the ratio of the distances between the point of application to the second end of the arm and the swivelling axis of the arm, respectively, the smaller the force by which the second end of the arm must be manually affected to obtain a sufficiently large compressive force to disengage the engagement between the contact plug and the female connector. In a second preferred embodiment of the contact plug according to the present invention, the hollowing can be made as a channel extending from the open into the casing, possibly straight through this casing, in a direction preferably transversely of the dismounting device, whereas the actuator is shaped as a slide displaceably mounted in this channel.

The slide can easily be operated by displacing the slide, by a force application in form of a pressure by a finger on the first slide end which is projecting from the channel, to an activation position in which the slide is pushed a distance into the channel and has displaced the dismounting device during this to the second position of this dismounting device.

In a contact plug arranged in this way, an application of force on the slide can simply be transmitted to the dismounting device.

The dismounting device can advantageously extend parallel to the pins and be actuated by actuating the actuator with only one hand. In case the dismounting device is located between the contact pins, these pins will serve to protect the dismounting device from being bent when it is projecting between the contact pins. However, the dismounting device can be located on any plane in the casing where a sufficiently long arm can be obtained to provide the necessary application of force to displace the dismounting device from its first to its second position.

The fit of the dismounting device displaceably mounted in the casing can be such that a friction or clamp force secures the dismounting device in unloaded state. The dismounting device can be removed from the contact plug if the contact plug is to be used as a conventional contact plug. This might e.g. be the case if the contact plug is to be used in a permanent installation instead of a temporary one. The second end part of the dismounting device can optionally have a pressure base received in a recess in the casing in the first position. Advantageously, the pressure base can have an extent not exceeding the distance between the contact pins .

In a preferred embodiment, by means of which it is possible to obtain an especially effective actuation of the dismounting device, the slide can be bevelled in the area of contacting the dismounting device at a not self-locking angle with the longitudinal direction of the dismounting device. This angle can be between 30 and 60° but will preferably be between 40 and 50°.

In addition by letting the first end part of the dismounting device be bevelled at mainly the same angle as the slide, the force is transmitted from the actuator to the dismounting device across a relatively large face of contact, whereby an effective functioning of the dismounting mechanism is ensured and the wear on its working parts is minimal.

The invention will be explained in greater details below, describing only exemplary embodiments with reference to the drawing, in which

Fig. 1 is a perspective view of a first embodiment of a contact plug according to the invention with the dismounting device in a second position and of a fraction of a socket to which the contact plug is to be coupled.

Fig. 2 shows the contact plug in fig. 1 but with the dismounting device in a first position when the contact plug is coupled to the socket.

Fig. 3 is a diagrammatic, partly sectional view taken along the line III-III of fig. 1. Fig. 4 is a diagrammatic, partly sectional view taken along the line IV-IV of fig. 2.

Fig. 5 is a perspective view of a second embodiment of a contact plug according to the invention with the dismounting device in second position and of a fraction of a socket to which the contact plug is to be coupled.

Fig. 6 shows the contact plug in fig. 5 but with the dismounting device in first position in which the contact plug is coupled to the socket.

Fig. 7 is a diagrammatic, partly sectional view taken along the line VII-VII of fig. 5.

Fig. 8 is a diagrammatic, partly sectional view taken along the line VIII-VIII of fig. 6.

Fig. 9 is a diagrammatic, partly sectional view through a third embodiment in a second position, and

Fig. 10 is a diagrammatic view of the embodiment in fig. 9 in first position.

Figs. 1 and 2 show a first embodiment of a contact plug according to the invention, designated generally by the reference numeral 1. The contact plug is guided in the direction of the arrow a in fig. 1 to engage a female connector 2 in a conventional socket generally designated by the reference numeral 3. In fig. 2, the contact plug has been coupled to the socket 3. This is not in itself part of the invention and will therefore not be described in detail.

The contact plug 1 has a casing 4, two contact pins 5,6, an electric wire 7 mounted in the casing 4, a hollowing in form of a groove 8 made in the casing 4 opposite the pins 5,6, and an actuator arm 9 located in the groove 8. The arm 9 is pivotally mounted about a swivelling axis 10 at the first end 11 of the arm, and it has a second end 12 completely received in the groove 8 in fig. 1. In addition, the contact plug 1 has an elongated dismounting device 13 having a first end part 14 and a second end part 15 which has a pressure base 16 which, in fig. 2, is received in a recess 17 in the face of contact 18 of the casing 4, the contact pins are projecting from this face of contact.

As seen best in fig. 3, the dismounting device 13 between the contact pins 5,6 is extending, in the second position in fig. 1, a distance x out from the casing 4. As seen best in fig. 4, this distance x corresponds to the distance by which the first end part 14 of the dismounting device 13 maximally lifts the arm 9 out of the groove 8 in the first position of the dismounting device 13 in fig. 2.

By bringing the contact plug from the state in fig. 4 to the state in fig. 3, the arm 9 is pressed down into the groove 8 by a force F , whereby the force is transmitted to the first end part 14 of the dismounting device 13 by an exchange of force. This exchange of force corresponds to the ratio of the distance from the point of application between the arm 9 and the dismounting device 13 to the second end 12 of the arm 9 to the distance from said point of application to the swivelling axis 10 of the arm.

Figs. 5 and 6 show a second embodiment of a contact plug 20 according to the invention mounted on a contact wire and for coupling with a socket 2. The contact plug 20 consists of a casing 21, two contact pins 22,23, a dismounting device 24, and a slide 25. The dismounting device 24 has a first end 26 with a bevel 27 of about 45° and a second end 28. The dismounting device 24 is located between the contact pins 22,23 and is extending parallel to these pins. The slide has a first free end 29 and a second end 30 received in the channel 31. The contact plug 20 is mounted in the direction of the arrow b in the female connector 3 in the socket 2, which is shown in detail in figs. 7 and 8, the dismounting device 24 being pushed into the casing 21 during this and the free end 29 of the slide 25 being pushed out of the channel 31 in the casing 24.

Fig. 7 shows how the slide 25 and the dismounting device 24 mutually affect each other in the second position of the dismounting device 24. The second end 30 of the slide 25 has a bevel 31 with an angle of about 45° corresponding to the angle of the bevel 27 of the dismounting device 24.

To reach the second position of the dismounting device 24 in fig. 7, the first end 29 of the slide 25 is affected by a force F making the bevel 31 on the second end 30 of the slide 25 slide along the bevel 27 on the first end 26 of the dismounting device 24. Thereby, the dismounting device is displaced a distance out of the casing 21 in direction towards the contact pins 22,23 and is pulling the contact pins 22,23 at least partly free of the female connector 3 during this.

Fig. 8 shows how the slide 25 and the dismounting device 24 mutually affect each other in the first position of the dismounting device 24.

The female connector 3 affects the second end 28 of the dismounting device 24 with a force N in the first position of the dismounting device. During this, the bevel 27 of the first end 26 of the dismounting device 24 is made to slide towards the bevel 31 of the second end 30 of the slide 25, and it pushes the first end of the slide 25 free of the casing 21.

Figs. 9 and 10 show a third embodiment of a contact plug 32 according to the present invention. The contact plug 32 is a modification of the contact plug 1 in figs. 3 and 4. Like parts are similarly referenced.

The contact plug 32 has a casing 33, a hollow swinging arm 34, a dismounting device 35, and two contact pins 5,6. The dismounting device has a first end part 36 and a second end part 37 with a pressure base 16 which is received in a recess 17 in the first position of the dismounting device 35.

A piece of the wire 7 is passed through the hollow swinging arm 34. This arm has a first end 38 for actuating the dismounting device 35 and a second end 39 for manually actuating the actuator with a force to push the dismounting device from its first to its second position. The swinging arm is swingingly mounted about a swivelling axis 40 in a hollowing 41 in the side of the casing 33 opposite the contact pins 5,6. The swinging arm 34 with the piece of wire 7 is received in the hollowing 41 in the first position of the dismounting device 35 in fig. 10. If the wire is pulled by means of a force F' , the swinging arm 34 will tip, whereby the dismounting device is pushed from the first position in fig. 10 to the second position in fig. 9, in which the contact plug is pulled free or easily can be pulled free of the socket 2.

Where the wire 7 is passed through the swinging arm 34, it acts as a useful extension of the arm z between the centre of rotation 40 and the second end 39 of the swinging arm 34. Thereby, the wire 7 can advantageously be used for increasing the exchange, by means of which the manual force application on the actuator is transmitted to the dismounting device.

This embodiment is especially expedient if the female connector is located in a not very accessible place.

To ensure that the contact plug and the female connector are sufficiently disengaged to easily separate them, the piece of the second end part of the dismounting device projecting from the casing has a length of between 0.2 and 1.2, preferably between 0.6 and 1.1, and especially between 0.8 and 1.0 times the length of the contact pins .

Within the scope of the invention, the contact plug 1 of figs. 1 and 2 can alternatively be made with the actuator and dismounting device of figs. 7-8, and the contact plug of figs. 5 and 6 can be made with an actuator in form of a swinging arm which is received in the casing.

Claims

Patent claims

1. A contact plug (1;20;32) of the kind that is adapted to be mounted on e.g. an electric wire (7) and comprises - a casing (4;21;33),

- at least two contact pins (5, 6,-22, 23) projecting from the casing (4; 21; 33) for detachably engaging complementarily shaped female connectors (2), a dismounting device (13; 24; 35) having a first (14; 26; 36) and a second end part (15; 28; 37) and mounted in the casing (4; 21,-33) displaceably between a first position in which the second end part (15; 28,-37) is at least mainly received in the casing (4;21;33), and a second position in which the second end part (15; 28; 37) is pushed out of the casing (4; 21; 33) to the same side as the contact plugs (5, 6; 22, 23), an actuator (9; 25; 34) for displacing the dismounting device (13; 24; 35) from the first to the second position by means of an application of force on the first end part (14;26;36) of the dismounting device (13 ; 24; 35) , a hollowing (8; 31; 41) made in the casing (4; 21; 33) on the opposite side of the contact pins (5, 6,-22, 23) for at least partly receiving the actuator (9; 25,-34) in the second position of the dismounting device (13 ; 24; 35) , and having a depth enabling the first end part (14; 26; 37) of the dismounting device (13; 24; 35) to extend into the hollowing (8; 31,-41) in the first position of the dismounting device (13;24;35).

2. A contact plug (1) according to claim 1, characterized in that the hollowing is made as a groove (8) extending transversely of the dismounting device (13), and that the actuator (9) has an arm with a first end (11) pivotally mounted in the groove (8) and a second end (12) located outside the groove (8) in the first position of the dismounting device (13) .

3. A contact plug (32) according to claim 1, characterized in that the hollowing is made as a groove (41) extending transversely of the dismounting device (35), and that the actuator (34) has an arm with a first end (38) pivotally mounted in the groove (41) and a second end (39) located in the groove (41) in the first position of the dismounting device (35) .

4. A contact plug (20) according to claim 1, characterized in that the hollowing is made as a channel (31) extending into the casing (21) from the open in a direction transverse of the dismounting device (24) , and that the actuator is a slide (25) displaceably mounted in the channel (31) between a free first position in which it is projecting from the channel (31) , and an activation position in which the slide (25) is pushed a distance into the channel (31) and has displaced the dismounting device (24) to the second position of this dismounting device.

5. A contact plug (20) according to claim 4, characterized in that the channel (31) is extending straight through the casing (21) .

6. A contact plug (20) according to claim 4 or 5, characterized in that the slide (25) is bevelled in the area of contacting the dismounting device (24) at a not self-locking angle with the longitudinal direction of the dismounting device (24) .

7. A contact plug (1;20;32) according to any of the claims 1 - 6, characterized in that the dismounting device (13; 24; 35) is extending parallel to the contact pins (5 , 6 ; 22 , 23 ) .

8. A contact plug (1;20;32) according to any of the claims 1 - 7, characterized in that the dismounting device (13;24;35) is displaceably located in the casing (4; 21; 33) with such a fit that the casing (4; 21; 33) affects the dismounting device with a friction force.

9. A contact plug (1;20;32) according to any of the claim 1 - 8, characterized in that the second end part (15; 28; 37) of the dismounting device (13; 24; 35) has a pressure base (16) received in a recess (17) in the casing (4; 21; 33) in the first position of the dismounting device (13;24;35).

10. A contact plug (20) according to any of the claim 6 - 9, characterized in that the first end part (26) of the dismounting device is bevelled at least mainly at the same angle as the slide (25) .

11. A contact plug (1;20;32) according to any of the claims 1 - 10, characterised in that the second end part (15; 28; 37) of the dismounting device (13; 24; 35) is extending out of the casing (4,-21; 33) in the second position of the dismounting device at a length of between 0.2 and 1.2, preferably between 0.6 and 1.1, and especially between 0.8 and 1.0 times the length of the contact pins (5,6;22,23).