IL91013A - Safety electrical socket - Google Patents

Description

The present invention relates to an electrioal socket, particularly to a socket having built-in safety means preventing the insertion of a single pin into the contact opening connected to the live wire.

Sockets of this type are particularly intended to prevent insertion of conducting single pins into the live wire contact by, for example, playing children, without impeding insertion of a plug connected to an electric appliance into said socket.

The most widely used type of such safety sockets is one in which a rotatable disc having openings corresponding to the contact openings is affixed to the outer side of the cover of the socket, urged by a spring into a position in which the openings in said disc do not correspond to the contact openings, thereby preventing the insertion of anything into said contact openings. In order to insert the plug, it must be inserted into the openings of said disc and afterwards rotated against the force of said spring until the openings in the disc coincide with the contact openings and then pushing the plug into the contact openings, thereby connecting the appliance to the current.

This relatively simple arrangement has two drawbacks. First, the cover disc may be rotated also by inserting a single pin into one opening and after this opening is aligned with a contact opening, the single pin will enter the contact, and, particularly if this contact is the live wire, an accident will follow. The second drawback is that the normal insertion of the plug is impeded, as a first step, the plug must be rotated until the openings in the cover disc are aligned with the contact openings.

There is also known another type of safety sockets, also intended to prevent insertion of single pins into the contact openings. In these sockets both contact openings are covered by a sliding plate arranged on the inner side of the cover plate of the socket, slidable on the insertion of the plug in a direction normal to the line connecting the contact openings, said sliding plate is slidable only in case when both contact pins of the plug are introduced simultaneously, and are provided by means locking said sliding plate in the covering position in case one tries to insert a single pin into one of the contact openings. A socket of this type is known, inter alia, from German Patent No. 22 10 513.

The present invention relates to a safety socket of the above type comprising a shield plate arranged between the socket cover plate and a holding plate, parallel to both, with a clearance on both sides of the same, guided for sliding movement in a direction normal to the line connecting the live and the neutral contact openings- and tiltable out of the plane parallel to said socket cover plate and said holding plate, said shield plate covering the live and the neutral contact openings, said shield plate being urged by a single or a plurality of springs towards the position in which it covers the contact openings, and interacting arresting means, provided on said sliding plate and/or said holding plate, locking the sliding plate against said sliding movement in case said sliding plate is tilted out of the plane parallel to the socket plate and the holding plate.

In this arrangement the plate covering the contact openings may slide into a position in which said contact openings are only freed when said plate remains parallel to both the socket cover and the holding plate and becomes locked when titled out from this position by an attempt to insert a single pin, or, for that matter, two pins, but not strictly simultaneously. By inserting two pins (the two prongs of the plug) in parallel and strictly simultaneously, the sliding plate is constrained to remain in the parallel position and therefore remains freely slidable, enabling the prongs to enter the contacts.

The sliding plate may be guided lor. said sliding motion, and held tiltably, with a clearance from both the socket cover and the holding plate, by various means, some of which are known, in general, per se. For example, it may slide along a rod held in the holding plate while being urged into the covering position by a spiral spring surrounding said rod, said clearance being established by rods at the middle line of the sliding plate or by suitable ridges, possibly cooperating with grooves, formed on said sliding plate, said holding plate or possibly also on the socket cover. The sliding plate may be guided also along both edges of the same and the guide rod dispensed with, the spring being held only in two corresponding recesses in the holding plate and the sliding plate.

Adaptation of the sliding plate for the guided sliding movement may be achieved by said sliding plate having its edge at the end facing the contact openings slanted or alternatively, said end facing the contact openings need not be slanted along the whole length thereof but only in its regions facing said contact openings.

Of course, in case there is a third contact for the earthing connection, this remains uncovered all the time and the entire safety arrangement is disposed away from this third opening facing the live wire and neutral contacts. Such embodiments are illustrated, in the plane view, but it is obvious that the invention is also applicable to sockets with only two contact openings without any alterations.

- A particular advantage , of the claimed, invention is that there is only a very small number of component parts.

The invention will be described in more detail on hand of the appended drawings. Owing to the simplicity of the arrangement, the drawings are schematic and restricted to the essential features only. In particular, the arrangements for guiding the sliding plate are not illustrated. As indicated above, these may be a rod held in the holding plate, on which rod the sliding plate slides, or more preferably guide rails on the sides of the same, which guide rails may be preferably integral with the holding plate.

The invention will be described in more detail on hand of the accompanying drawings.

Figure 1 . is an isometric view of the safety arrangement mounted on the socket cover; Figure 2 is a plane view of the arrangement of Figure 1; Figures 2a to 2f are sectional views along the line A-A in Fig. 2; Figures 2al to 2aIII illustrate the arrest of the sliding shield plate by the arresting means; Figure 2g is an isometric sectional view of an additional embodiment; Figure 2h is a cross-sectional view, along the line B-B of Fig. 2g; Figure 1 is an isometric view towards the back side of the socket cover. Reference number (1) denotes this back side, numeral (2) designates the holding plate, in the illustrated embodiment affixed to the socket cover (1) at (3) (holding plate (2) can also be affixed to the over (1) at (6) - not illustrated), (4) is the sliding shield plate, which covers the live wire and the neutral contacts and is slidable in the direction of the arrow. In sockets where the socket cover is attached to the body of the socket by a screw connection in a central, or possibly off-central post, the sliding shield plate (4) may be of a U-shape, the limbs of the U covering the live wire and the neutral contact openings, the space between the two limbs accomodating said central post.

Numeral (6) designates a bar affixed to the socket cover (1) , retaining sliding plate (4); this bar optionally has a recess (7) for accomodating the earthing contact in case such is present.

Holding plate (2) may be integrally moulded with the socket cover (1), if applicable, or alternatively, holding plate (2) may be affixed at (3) to the socket cover by suitable means, such as achesives or screw connections. 9 1 0 1 3 / 2 Bar (6) may also be affixed to the socket cover* but it may also be integrally moulded with the same, if applicable, sliding plate (4) is simply freely inserted at a suitable stage. Said sliding plate is urged towards the position covering the contacts by a spring, indicated in Fig. 2 by (7). In the specific embodiment shown in this Figure, the spring is held within recesses in holding plate (2) and sliding plate ( ) .

Figure 2, being a plane view corresponding to Fig. 1, is not described separately. The line A-A indicates the section shown im more detail in Figs. 2a to 2f .

Figures 2a to 2f illustrate particular embodiments of the locking means.

Fig. 2a illustrates the step formed in the holding plate, designated by (8). It is clear that in case the sliding plate is titled out from the parallel position, the higher end thereof engages this step and plate (4) is prevented from sliding.

For sake of further clarity, Figs. 2aII and 2aIII, illustrate the arrest of the sliding plate (4) by step (8), when plate (4) is tilted. Fig. 2al illusrates the possibility of free sliding of plate (4), when in the plane parallel to both socket cover (1) and holding plate (2). In Figures 2al, II and III, identical parts are designated by same numerals as in Figs. 1 and 2a.

Fig. 2b illustrates an extension of holding plate (2) designated by (9). This forms, together with the upper part of the holding plate, a recess (10), accomodating the sliding plate (4) only in case it remains parallel to the upper and lower parts of holding plate (2).

Fig. 2c illustrates a bar (11), formed on the holding plate (2), co-operating with a step (12) on the sliding plate.

When the sliding . plate, is tilted, bar (11) and step (12) interengage, locking the sliding plate.

Fig. 2d illustrates a groove (13) formed in the holding plate and a bar (14) on the sliding plate. When the sliding plate is tilted groove (13) and bar (14) interengage, locking the sliding plate.

Fig. 2e illustrates a step (15) on the sliding plate and a bar (16) on the inner side of the socket cover. When plate (4) is tilted, step (15) engages bar (16), locking the plate (4).

Fig. 2f illustrates a bar (17) on the sliding plate (4) and a groove (18) in the socket cover. When plate 4 is tilted bar (17) enters groove (18), locking plate 4.

Fig. 2h which is a cross-section along the line B-3 in Fig. 2g which is an isometric cross-section, illustrates the embodiment in which a protrusion (19) . on sliding plate (4) enters the opening in the socket cover (1) for the insertion of the plug, indicated by (20), thereby locking sliding plate (4).

As may be seen in Figs. 2a to 2f and 2h, the parts (21) of the egde of sliding plate (4), facing the contact openings, are slanted, enabling the sliding of plate (4), when, for example, the two prongs of a plug are inserted into said contact openings.

An additional ridge on said' shield plate, preventing the slanted insertion of a thin wire or pin may be provided in all of the above described embodiments.

The preceding detailed description applies in particular to sockets of the type in which the electrical contact elements are fixedly held in the body of the socket and the cover plate is essentially a flat plate having openings for inserting the plug which correspond to the contact elements in the body of the socket. This cover plate is attached to the body of the socket, in the majority of the available sockets, by a central or off-center screw post connection in which case the sliding plate may have an appropriate recess for accomodating the post, it may be U-shaped, as described and illustrated above.

Other types of wall sockets are also available, in which the electrical contact elements are loosely inserted in the body of . the socket and the socket cover, in addition to covering the electrical elements, locks them into position. The safety arrangement, as defined in the appended claims, is equally adaptable to sockets of this type, the socket cover being appropriately modified to accomodate said arrangement.

Claims (11)

CLAIMS:

1. Electrical safety socket preventing the insertion of a single pin into any of the contact openings comprising a shield plate arranged between the socket cover plate and a holding plate, parallel to both with a clearance on both sides of the same guided for sliding movement in a direction normal to the line connecting the live and the neutral contact openings and tiltable out of the plane parallel to said socket cover plate and said holding plate, said shield plate covering the live and the neutral contact openings, said shield plate being urged by a single or a plurality of springs towards the position in which it covers the contact openings and interacting arresting means, provided on said sliding plate and/or on said holding plate, locking the sliding plate against said sliding movement in case said sliding plate is tilted out of the plane parallel to the socket cover plate and the holding plate.

2. The safety socket according to claim 1 wherein said arresting means comprise a step formed on the side of the holding plate facing the sliding plate, engaging the sliding plate when the same is tilted out of the plane parallel to the socket coverplate and the holding plate.

3. The safety socket according to claim 1 wherein said arresting means comprise an extension of the holding plate adjacent to the socket cover plate, forming, together with the holding plate, a recess accomodating the sliding plate only if the same is in the position parallel to the holding plate. .

4. The safety socket according to claim 1 wherein said arresting means comprise a bar formed on the side of the holding plate facing the sliding plate, co-operating wit ' a step formed on the end of the sliding plate, remote from the contact openings.

5. The safety socket according to claim 1 wherein said arresting means comprise a groove formed on the side of the holding plate facing the sliding plate co-operating with a nut formed on the end of the sliding plate remote from the contact openings.

6. The safety socket according to claim 1, wherein said arresting means comprise a bar affixed to the socket cover co-operating with a step formed on the end of the sliding plate remote from the contact openings, on the side facing the socket cover.

7. The safety socket according to claim 1 wherein said arresting means comprise a groove formed in the socket cover, co-operating with a nut formed on the end of the sliding plate remote from the contact openings, on the side facing the socket cover.

8. The safety socket according to claim 1 wherein said arresting means comprise a •protrusion formed on the end of the sliding plate near to the contact openings, entering the openings for the insertion of the plug in the socket cover.

9. A safety socket according to any one of the preceding claims wherein said shield plate is a U-shaped plate, the limbs of the U covering the live and neutral connections.

10. The safety socket according to any one of the preceding claims wherein an additional ridge is provided on said shield plate. -

11. - FOR APrUCAHTS