A touch-safe socket for electrical articles, such as bulbs having threads, is provided with a movable carriage-carrying poles which are connected to an electrical supply via a wire. The movable carriage has threads which cooperate with threads on the electrical article, and when the electrical article is screwed into the movable carriage, the movement will cause the poles to make contact with poles which are secured to a stationary plate. Further, a movable bridge having poles is arranged inside the socket, which, when the electrical article is screwed in, will be moved into the socket and also make contact with the poles on the stationary plate.

BACKGROUND OF THE INVENTION

FIELD OF INVENTION

The invention relates to a touch-safe socket for electrical articles, such as bulbs, having poles, wherein at least two poles connected to an electrical supply are mounted inside the socket, and wherein the socket is provided with movable means to protect against touch of the poles of the socket, the movable means being affected during the insertion of the electrical article into the socket, and wherein the movable means are formed by a movable carriage which carries the poles, and wherein the movement is provided by the insertion of the bulb into the socket so that the poles make contact with two poles which are secured to a stationary plate, whose poles extend through the stationary plate.

THE PRIOR ART

U.S. Pat. No. 6,491,534 discloses a touch-safe socket, where, When a bulb is screwed into the socket, a spring-biased disc, which has electrical terminals, can move the terminals of the disc down against current-carrying poles at the bottom of the socket and thereby provide voltage to the bulb.

In another embodiment according to the US patent, the movable parts are formed by spring-biased push-buttons configured as switches which are arranged in the threads of the socket, so that the switches, when the bulb is screwed into the threads, will press the push-buttons home and thereby provide electric voltage to the bulb.

An embodiment including both safety systems is also described.

In the known structure, it will be relatively easy for a person to press the disc and/or the push-buttons with the fingers and thereby connect voltage to the fingers, causing electric shock.

Further, DE Offenlegungsschrift No. 1 539 415 discloses a touch-safe socket. A drawback of this known socket is that electrical contact to the poles of the socket may be made by a pull of the threads of the socket.

Accordingly, an object of the invention is to provide a touch-safe socket for electrical articles, such as bulbs, where it is practically impossible to get an electric shock if a person's fingers are moved into the socket.

SUMMARY OF THE INVENTION

The object of the invention is achieved by a touch-safe socket, wherein when being inserted into the socket, the poles of an electrical article touch poles which are arranged on a movable bridge, the poles extending through the bridge so that, when being moved, the poles of the bridge make contact with the poles on the stationary plate.

Hereby, a pull of the threads of the socket cannot result in electrical contact with the free poles of the socket, it being required that also the movable bridge is to be pressed into the socket before electrical contact can be made.

For safe control of the movable bridge it is advantageous if the movable bridge is spring-biased.

It is a further characteristic of the invention, that, when being moved into the socket, the electrical article first moves the movable bridge into the socket, where the poles of the movable bridge make contact with the poles on the stationary plate, following which the movable carriage is moved in a direction out of the socket until the movable carriage makes contact with the poles on the stationary plate.

For safe control of the movable carriage it is advantageous if the movable carriage is provided with threads which cooperate with threads on the electrical article, and the stationary plate is provided inside a housing in which the movable carriage and the movable bridge are incorporated.

For further stabilization of the mechanical, movable parts in the touch-safe socket, it is advantageous if the stationary plate is provided with through bores through which legs on the movable carriage and the movable bridge may be moved.

In order to indicate that an electrical connection is established to the electrical article, it is an advantage if a click sound is generated or light is produced in a light-emitting diode which is mounted externally on the housing, at the moment when an electrical connection is established between the poles of the movable carriage and the poles of the electrical article.

This is particularly advantageous if a defective electrical article, such as a bulb, is introduced into the touch-safe socket, as it may then be found out quickly whether the bulb is dead.

The invention will now be explained more fully with reference to the drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In the figures, the numeral1generally designates a touch-safe socket according to the invention. It consists of a housing2into which, at the bottom thereof, a wire3is introduced, having two insulated conductors4which are connected to poles5on a movable carriage6. As will be seen, the poles5protrude up through a plate part on the carriage6.

The carriage6has a plurality of legs8, two of which are shown (there are preferably four which are disposed equidistantly on a circle), which extend through a stationary plate11secured to the housing2. At its free upper end the movable carriage has threads9.

Further, the housing2also accommodates a movable bridge14having legs15,16which extend through the stationary plate11. The movable bridge14is provided with poles17,18which extend through an upper plate part of the bridge14.

An annular, movable contact spring10is arranged along the edge of the plate part and is movable relative to the threads9, but so that there is constant contact between the threads9and the contact spring10.

The legs15,16are moreover biased by two springs7, which are disposed around the legs15,16between the lower side of the upper plate on the movable bridge14and the upper side of the stationary plate11.

Finally, the figures show a bulb19which may be an ordinary incandescent bulb or an energy-saving bulb having, e.g., the thread sizes E14, E27, E40.

The threads20of the bulb, which also serve as a pole, have another pole which is designated21.

It will now be explained how the touch-safe socket according to the invention operates.

With reference toFIG. 1A, the touch-safe socket is shown before a bulb19is introduced into it.

FIG. 1Bshows a bulb just before it is inserted into the socket.

InFIG. 1C, the threads20of the bulb have been moved into the threads9on the movable carriage6, but without it having moved as yet.

On the other hand, the movable bridge14has moved, which, as will be seen, has been pressed down in the direction of the arrow23, so that the springs7are compressed, thereby making electrical contact between the pole17on the movable bridge14and the pole21on the bulb.

When the bulb19is screwed further in, the movable carriage6will be pulled up in the direction of the arrow22, as the movable bridge cannot be pressed further into the touch-safe socket, which causes the threads9on the movable carriage6to be pulled outwards.

When the bulb has been screwed sufficiently far into the touch-safe socket1, an electrical connection will be established between the poles12,13on the stationary plate11and the poles5on the movable carriage6, following which the bulb receives current and emits light.

Optionally, a mechanical part is arranged in the touch-safe socket, which will emit a click sound when the bulb is connected.

Alternatively, a light-emitting diode, which emits light when current is applied, may also be arranged somewhere on the outer side of the housing2.

Further, it should be noted that the touch-safe socket also provides some protection if the movable bridge is replaced by a fixed bridge which is located as shown inFIG. 1C