ELECTRICAL DEVICE FOR SWITCHING ON RESERVE POWER

Abstract: An electrical appliance (1) for switching on reserve power is adapted to be installed in an electric mains (7a, 7b) with primary power supply and comprises a casing (2) having an input (5) and an output (6) which are electrically interconnected by a first line (4) and adapted to be connected to the mains; a switch (3) connected in the first line; and an appliance inlet (10) connected to the first line by a second line (13). This appliance is characterised by an operating cover (9) which is movably mounted in the casing (2) for shifting between a first position in which it covers the inlet (10) and allows the switch (3) to close the first line (4) between the input (5) and the output (6), and a second position in which it uncovers the inlet (10) and causes the switch (3) to open the first line (4) between the input (5) and the output (6), thus enabling current from a reserve power unit to flow, via a cable (12), or the like, and a flexible lead outlet (11), to the inlet (10) and from there to the output (6) via the second line (13), while the connection of the second line (13) to the input (5) is open.

Description: ELECTRICAL DEVICE FOR SWITCHING ON RESERVE POWER The present invention relates to an electrical appliance for switching on reserve power, said appliance being adapted for installation in an electric mains with primary power supply and comprising a casing having an input and an output which are electrically interconnected by a first line and adapted to be connected to the mains; a switch connected in said first line; and an appliance inlet connected to said first line by a second line. More precisely, the invention concerns a mechanically locked inlet, viz. a reserve power inlet, enabling power supply from a reserve power unit to the electric mains of e.g. a building when the primary power supply fails, for instance because a sector fuse has blown, a power trans¬ mission line been damaged, or a switching station dropped out. Present-day electrical appliances for switching on reserve power relies either on at least two mechanically operated switches connected in series or on at least two electrically operated switches connected in series. In both cases, the appliance inlets are not touchproof, and the use of two switches (either mechanical or electrical) connected in series ensures that the inlet pins do not become live when the mains is connected. One object of the present invention is to provide an electrical appliance for switching on reserve power which is of simple and inexpensive design. Another object of the invention is to provide such an electrical appliance, which not only has few movable parts but also is highly reliable in service. Yet another object of the invention is to provide such an electrical device, which is touchproof, and easy to install and operate. According to the invention, these objects are achiev¬ ed by an electrical appliance characterised by an operat¬ ing cover which is movably mounted in said casing for shifting between a first position in which it covers the inlet and allows the switch to close the first line between the input and the output, and a second position in which it uncovers the inlet and causes the switch to open the first line between the input and the output, thus enabling current from a reserve power unit to flow, through a cable, or the like, and a flexible lead outlet, to the inlet and from there to the output via the second line, while the connection of the second line to the input is open. Further distinctive features of the invention are recited in the subclaims. The preferred embodiments of the invention will be described below, reference being had to the accompanying drawings, in which Fig. 1 is a schematic front view of the inventive appliance with the operating cover in the first position, Fig. 2 is a schematic front view of the inventive device with the operating cover in the second position and with the appliance inlet uncovered to receive a flexible lead outlet, Fig. 3 is a section taken along the line A-A in Fig. 2 and showing the flexible lead outlet with the asso¬ ciated cable when connected, Fig. 4 is a schematic front view of an alternative embodiment of the inventive appliance, the operating cover being in the first position, Fig. 5 is a schematic front view of the appliance in Fig. 4, the operating cover being in the second position and the appliance inlet being uncovered to receive the flexible lead outlet, Fig. 6 is a side view of another alternative embodi¬ ment of the inventive appliance, Fig. 7 is a schematic front view of the appliance in Fig. 6, Figs 8 and 9 are schematic front views illustrating yet another alternative embodiment of the inventive appli- ance, the operating cover being in the first and the second position, respectively, and Figs 10 and 11 are schematic front views illustrating an embodiment of the inventive appliance in which the ope¬ rating cover is connected to the switch. In the drawings, like details are identified by like numerals. In Fig. 7, the operating cover is indicated by full lines when in the first position and by broken lines when in the second position. Figs 1-3 illustrate a preferred embodiment of an electrical appliance 1 of the invention for switching on reserve power. This appliance comprises a housing or cas¬ ing 2 made of a suitable impact-resistant, electrically insulating material commonly used for enclosing switches or the like. The casing contains a switch 3 connected in a first line 4 which is enclosed in the casing 2 and con¬ nects an input 5 in the casing of the appliance 1 to the output 6 thereof. The switch 3 can thus close and open the electric connection (electric circuit) between the input 5 and the output 6 of the appliance 1. The appliance 1, with its input 5 and its output 6, is adapted for installation in an electric mains 7a, 7b with primary power supply. The switch 3 is operated by an operating means 8 projecting therefrom (see Fig. 3). In this embodiment, the means 8 is nonrotatably connected to an operating cover 9. The appliance 1 further comprises a reserve power inlet 10 which is also enclosed in the casing 2 at a dis¬ tance from the switch 3, preferably in a compartment of the casing separate from the switch. The inlet 10 com¬ prises a socket adapted to cooperate with the plug of a flexible lead outlet 11 which, via a cable 12 or the like, is connected to a reserve power unit (not shown). The inlet 10 is further connected to the first line 4 by a second line 13 also enclosed in the casing 2. As is apparent from Fig. 2, the second line 13 is connected to the first line 4 at a point between the switch 3 and the output 6, for reasons given below. The operating cover 9 is movably mounted in the cas¬ ing 2. In this embodiment, it is pivotable about an axis 14 coinciding with the axis of rotation of the operating means 8 of the switch 3. The operating cover is pivotable between two positions. In the first position, shown in Fig. 1, the operating cover 9 conceals the inlet 10, thus preventing anyone from accidentally touching or having access to the inlet socket which at all times is live. In this position, the switch 3 is closed, the input 5 is electrically connected to the output 6 by the first line 4 and the switch, and the primary power supply of the elec¬ tric mains 7a, 7b occurs through the appliance 1, as illu¬ strated by the arrows in Fig. 1. If the primary power supply should fail or if for some other reason a reserve power unit is to be connected to the user mains or the internal electric mains 7b, the operating cover 9 is pivoted to the second position shown in Fig. 2. Thus, the switch 3 is brought to its opening state and the appliance inlet 10 is uncovered, thus enabl¬ ing connection of the flexible lead outlet 11 to the inlet 10, i.e. connection of the socket and the plug. Now, cur¬ rent from the reserve power unit can flow through the cable 12, the flexible lead outlet 11, the inlet 10, and the second line 13 to the first line 4 and the output 6, whence it flows to the user outlets along the internal electric mains 7b whereas not to the primary power supply 7a of the mains, since the switch 3 has opened the first line 4 between the switch and the input 5 and, consequent¬ ly, the connection of the second line 13 to the input 5, as illustrated by the arrows in Fig. 2. In the second position, the flexible lead outlet 11 also prevents the operating cover 9 from being pivoted back to the first position, by the operating cover extend- ing beyond the flexible lead outlet on a level therewith, for which reason the switch 3 is mechanically maintained in the opening state, see especially Fig. 3. This means that, if the primary power supply should start operating again or if one should wish to utilise the primary power supply 7a of the mains, the current from the primary power supply is prevented from flowing to the internal electric mains 7b or to the reserve power unit, which might cause damage. Figs 4 and 5 illustrate an alternative embodiment of the inventive appliance. In this embodiment, the operating cover 9 mounted in the casing 2 is not pivotable, but slidable in the longitudinal direction of the casing between said two positions. Furthermore, the operating cover 9 is not connected to the operating means 8 of the switch 3. The operating cover 9 may be slidably fixed to the casing by guide strips (Fig. 6), a nut and groove assembly, or any other optional means. Further, the casing 2 is provided with abutment means (not shown) restricting the movement of the operating cover 9 which thus can only move between said two positions and is prevented from being inadvertently removed from the appliance 1. In the first position, shown in Fig. 4, the operating cover 9 conceals the inlet 10, and the switch 3, in this embodiment a push-button switch, is in its closing state, connecting the input 5 to the output 6. Since the operat¬ ing means 8 of the switch is in its most projecting posi¬ tion when the switch is in the closing state, the operat¬ ing means 8 then extends past the operating cover 9 and mechanically prevents the latter from occupying the second position and uncovering the inlet 10. To move the operating cover 9 to the second position (shown in Fig. 5), the operating means 8 must be depress¬ ed, so that the switch 3 is brought to its opening state. Then, the operating cover 9 can be moved to the second position, thus opening the first line 4 and uncovering the inlet 10 for connection to the flexible lead outlet (not shown), as above. Since the .operating means 8 is concealed by the operating cover 9, it is impossible to unintentionally turn on the switch 3. If the operating cover 9 is to be pivoted back to the first position, the flexible lead outlet must first be removed from the appliance inlet. After the operating cover has been moved to the first position, the switch 3 can be turned on, thus connecting the input 5 to the output 6, as shown in Fig. 4. Figs 6 and 7 illustrate an alternative embodiment of the invention which comprises a toggle switch 3 whose operating means 8 is a toggle which can be moved trans¬ versely of the longitudinal direction of the appliance 1. In Fig. 6, being a side view of the appliance 1, the operating cover 9 is slidable between a pair of parallel guide strips 15 in the casing 2. The toggle 8 here is in its uppermost position, the operating cover 9 is in the first position in which it covers the inlet 10, and the switch 3 is in its closing state in which the input 5 is connected to the output 6, and the operating cover is locked in this position (see Fig. 7). In this embodiment, the operating cover 9 has a recess 16. When the operating cover 9 is to be moved to the se¬ cond position, the toggle 8 must be returned to its lowermost position (shown by broken lines in Fig. 7), so that the switch 3 is brought to its opening state. Owing to its recess 16, the operating cover 9 can then be moved to the second position, thereby opening the first line 4 and uncovering the inlet 10 for connection to the flex- ible lead outlet (not shown), as above. As previously, the operating cover 9 prevents the switch 3 from being inadvertently turned on. The operating cover is returned to the first position as above. Figs 8 and 9 illustrate yet another embodiment of the inventive appliance, which has a rotary switch 3 whose operating means 8 is a disc-shaped knob. The knob 8 may occupy a vertical position, shown in Fig. 8, in which the operating cover 9 is in its first, locked position, covering the inlet 10, and the switch 3 is in its closing state, as above. In this embodiment, the operating cover 9 has a recess 16 and a longitudinal slot 17. In order to move the operating cover 9 to the second position, shown in Fig. 9, the knob 8 must be turned in the recess 16 of the operating cover 9 to what is a hori¬ zontal position in the Figure, the knob 8 being aligned with the slot 17 and the switch 3 being in the opening state. Owing to its slot 17, the operating cover 9 may then be shifted to the second position in which the first line 4 is open and the inlet 10 is uncovered for connec¬ tion to the flexible lead outlet (not shown), as above. The slot 17 of the operating cover prevents the switch 3 from being unintentionally turned on, and the operating cover 9 is returned to the first position, as above. In the embodiment of Figs 10 and 11, the operating cover is connected to the operating means of a switch, such as the toggle 8 of a toggle switch 3, as in the embodiment shown in Figs 1-3. In this embodiment, the toggle 8, unlike the toggle 8 in Figs 6 and 7, can be moved in the longitudinal direction of the appliance 1. For instance, the toggle 8 may project through a recess 16 in the operating cover 9. On condition that the toggle, upon displacement of the operating cover, is moved between two positions in which the switch 3 is in the closing state (Fig. 10) and in the opening state (Fig. 11), respectively, the toggle can be connected to the operating cover in any optional manner. In this embodiment, the switch is thus directly operated by the operating cover 9 being moved between its two positions. Otherwise, the appliance 1 functions as above. In some applications of the invention, a spring means (not shown) is suitably arranged in the casing 2 to bias the operating cover 9 towards the first position so that it strives to cover the appliance inlet 10 as soon as the flexible lead outlet 11 has been removed there¬ from. It goes without saying that the invention is by no means restricted to the embodiments described above and shown in the drawings, but may be modified in many ways within the scope of the appended claims.

Claims: CLAIMS 1. An electrical appliance (1) for switching on reserve power, said appliance being adapted for instal¬ lation in an electric mains (7a, 7b) with primary power supply and comprising a casing (2) having an input (5) and an output (6) which are electrically interconnected by a first line (4) and adapted to be connected to the mains; a switch (3) connected in said first line; and an appliance inlet (10) connected to said first line by a second line (13), c h a r a c t e r i s e d by an ope¬ rating cover (9) which is movably mounted in said casing (2) for shifting between a first position in which it covers the inlet (10) and allows the switch (3) to close the first line (4) between the input (5) and the output (6), and a second position in which it uncovers the inlet (10) and causes the switch (3) to open the first line (4) between the input (5) and the output (6), thus enabling current from a reserve power unit to flow, through a cable (12), or the like, and a flexible lead outlet (11), to the inlet ' (10) and from there to the output (6) via the second line (13), while the connection of the second line (13) to the input (5) is open. 2. Appliance as claimed in claim 1, c h a r a c ¬ t e r i s e d in that the operating cover (9) is pivot- ably mounted and connected to the operating means (8) of the switch (3), such that said cover, when in said first position, brings the switch (3) to closing state and, when in said second position, brings the switch (3) to opening state. 3. Appliance as claimed in claim 1, c h a r a c ¬ t e r i s e d in that the operating cover (9) is slid¬ able in the longitudinal direction of the casing (2), such that when in said second position, it uncovers the inlet (10), but locks the switch (3) in the opening state. 4. Appliance as claimed in claim 3, c h a r a c ¬ t e r i s e d in that the operating cover (9) is dis- placeable from said first position, allowing operation of the switch (3), to said second position, only when the switch (3) is in the opening state. 5. Appliance as claimed in claim 4, c h a r a c ¬ t e r i s e d in that the operating cover (9) when in said second position completely covers the operating means (8) of the switch (3). 6. Appliance as claimed in claim 4, c h a r a c ¬ t e r i s e d in that the operating cover (9) when in said second position blocks the switch-on position of the operating means (8). 7. Appliance as claimed in claim 4, c h a r a c - t e r i s e d in that the operating cover (9) has an elongate slot (17) which, when the operating cover is in said second position, nonrotatably receives the operating means (8) of the switch (3). 8. Appliance as claimed in claim 3, c h a r a c - t e r i s e d in that the operating cover (9) is con¬ nected to the operating means (8) of the switch (3), such that the switch (3), upon displacement of the operating cover (9) from said first to said second position, is brought from closing state to opening state, and vice versa. 9. Appliance as claimed in any one of the preceding claims, c h a r a c t e r i s e d in that the operating cover (9) is biased towards said first position.

Inventors: ANDERSSON BJOERN, OLOFSSON JAN OLOF, ANDERSSON, BJOERN, OLOFSSON, JAN, OLOF
Applicants: STRETH I OESTERSUND AKTIEBOLAG
Application year: 1990
Main classification: H01R13
IPC codes: H01R13