EP0017819A1 - On-load low tension switch with fuse - Google Patents

Abstract

1. A low-voltage load switch having a safety fuse (hereinafter referred to as a fuse switch), the fuse link (6) of which is arranged under spring force between a head contact, which is additionally covered by a lid (5) which can be in the form of a screw cap (3), and a base contact (4), of a fuse mounting, and in the current supply to which is arranged a load switch (1) which is coupled to the lid (5) and which suddenly releases the contacts by way of a mechanism (14) in the form of a toggle lever, and which, without the fuse link (6), is locked in an open position, wherein ventilating channels ensure that the temperature of the connecting terminals does not exceed a given operating temperature, characterised in that a) a movable magazine (7) made of high temperature-resistant material is raised from the base contact (4) of the fuse mounting in the direction of the imaginary line (10) connecting it to the head contact under spring force (spring 9) with the screw cap (3) and the fuse link (6) removed, and that this base contact (4) maintains the fuse link (6) under pressure with respect to the screw cap (3) which, from the point of view of exchanging the fuse, retains the direction of the connection line (10) and thereby produces the contact force on the head contact and the base contact (4) of the fuse link (6), b) that the load switch (1) comprises a contact arrangement (contact members 12, 13) which is such that the imaginary line (11) connecting its contacts is inclined to the line (10) connecting the head contact and the base contact (4) of the fuse mounting, and that the lid (5) laterally prevents grasping of the screw cap (3), c) and that from the contacts of the load switch (1), a ventilating channel (53) leads past the magazine (7).

Description

The invention relates to a low-voltage circuit breaker with fuse, hereinafter referred to as a fuse switch, as described in the preamble of the main claim. The fuse link is arranged between an additional head contact covered by a flap and a foot contact of a fuse base. A power switch coupled to the flap is arranged in the power supply of the fuse base and is locked in the open position when the fuse link is removed.

In such a known fuse switch (DE-AS 23 34 595), the screw cap of the fuse link can be actuated with the flap closed, as a result of which the contacts are exposed to particular loads when the switch is switched slowly. The contact pressure between the fuse link and the foot contact of the device depends on how strongly an operator pulls the fuse link.

• Insbesondere muß Stromdiebstahl sowohl bei eingesetztem als auch bei herausgenommenem Sicherungseinsatz verhindert werden. Andererseits muß sowohl für den Bedienenden als auch für das Gerät besondere Sicherheit erzielt werden.

Fuse switches are intended to increase the safe operation of fuses by laypersons. You would also like to use fuse switches in distributors in the supply to the meter, i.e. in the uncounted current range of a system. For example, one thinks of using instead of a conventional main fuse. Previous meter backup fuses are usually arranged in sealable devices, whereby the fuse links may only be used and replaced by trained and authorized personnel. In order to enable operation by laypersons with counter backups, special requirements must be met:

• In particular, theft of electricity must be prevented both when the fuse link is inserted and when it is removed. On the other hand, special safety must be achieved for both the operator and the device.

In the case of a known fuse switch, the area of use for the fuse link is covered by a flap which closes fully at the edge (DE-AS 11 41 700).

In the case of screw locks, the contact pressure at the connection flaps of the fuse link is created by screwing the screw cap into a threaded part, the so-called threaded eyeglass. The contact pressure therefore depends on the operator. Too little contact pressure leads to increased contact resistance and can damage the contact points after a long period of operation. Since meter backup fuses are only exchanged rarely, usually only after very long operating times, a sufficiently high contact pressure and a correspondingly low contact resistance with a predetermined value must be ensured.

In order to make contact only after locking an insulating cap, lugs and recesses are provided in a known lower fuse part (DE-AS 24 09 238). The insulating cap, with the fuse insert inserted, is first inserted in the axial direction up to a stop and then guided into a latching position by movement perpendicular to the longitudinal axis. This represents an unusual movement sequence for the operators and, due to the tolerances of the latching means, a constant contact pressure is not guaranteed here either.

Fuses which can be switched off are known (DE-OS 26 42 223), in which the contact to the fuse link is made after insertion by a rotary movement in the manner of a toggle switch. Since tolerances must also be compensated for here, the contacts are designed to be resilient, which is why they can only carry weak currents.

In another known fuse switch with flap (DE-OS 26 18 360), a foot contact is inclined when switching and replacing the fuse link. Another known switch fuse works similarly (DE-OS 27 22 279).

The invention is based on the finding that obliquely lifting foot contacts can lead to loosening of the fuse insert if manual switching is frequent without changing the fuse link.

The invention has for its object to develop a compact fuse switch in which the power loss of the fuse link can be derived to the outside, the contact pressure regardless of the operator and of tolerances is achieved and that even when switching under load, contacts cannot scorch during switching or afterwards in long-term operation.

The solution to the described problem lies in a fuse switch with the characterizing features of claim 1. Through the magazine that receives the fuse link, the foot contact is guided on the one hand in the direction of the axis of the fuse link and, on the other hand, the fuse link is shielded against switching gases of the circuit breaker. Because of the spring that acts on the magazine, the contact pressure is independent of the operator and of tolerances. As long as the spring acting on the magazine is harder than a contact pressure spring, which ensures the contact pressure in the load switch, this guiding property is retained.

Due to the contact arrangement in the load switch, according to which the imaginary connecting line of the contacts is inclined to the connecting line of the head and foot contacts of the fuse base, a low device construction is achieved with a large switching path or stroke of the switching contacts. The flap on the side prevents the screw cap from being screwed onto the fuse link before the flap is actuated. This and because the contacts are suddenly released via a mechanism like a toggle lever, ensures reliable switching. The contacts of the circuit breaker can therefore not. scorched.

With a compact construction of the fuse switch, heat dissipation is made possible by the construction described, by passing a ventilation channel past the magazine from the contacts of the load switch. This can be the case with a narrow housing of the fuse switch below the magazine.

In the case of a fuse switch which, unlike the fuse switch according to the invention, cannot be switched under load, the connecting line through the contacts of a switch to the connecting line through the head and foot contact of the fuse link is inclined (DE-OS 24 45 262). Apart from the fact that the switch can only be connected upstream of the fuse link by appropriate external wiring, a flap and a magazine are missing, so that the foot contact itself is designed as a spring. This results in insufficient contact pressure for a load as a load switch. Since the spring action can also only be weak, a lever of the switch is provided with a nose under the fuse insert in order to lift the fuse insert up for replacement. Such a circuit breaker is not protected against being switched on again without an inserted fuse link. It is therefore not secured against theft of electricity. In addition, it could be switched so slowly that the contacts could scorch while sliding off an inclined plane.

The fuse switch according to the invention, however, is designed as a load switch that allows it, even under load. switch and replace the fuse safely.

The head contact of the fuse link can be arranged in a screw cap made of a handle and threaded sleeve in a manner known per se. Advantageously, however, a viewing window is permanently clamped between the handle of the screw cap and the threaded sleeve firmly connected to it. This further increases security against power theft.

According to one embodiment, the threaded sleeve to the viewing window forms a bottle-neck-like extension which, after the fuse link has responded, receives the discarded indicator sheet. Advantageously, the handle of the screw cap forms grip ribs and rib-shaped depressions on its outer edge, which are drawn over rounded edges up to the front side close to the viewing window. As a result, the screw cap can also be screwed in and out more easily if it protrudes only slightly over the housing edge encompassing it.

It is expedient to design the magazine from ceramic material, since ceramic, with high temperature resistance, has better heat dissipation than molding material or plastic.

The height of the handle of the screw cap is expediently matched to the stroke existing between the switch-on position and the switch-off position of the fuse base such that it is always in a gap-like connection to a trough-shaped edge of the housing surrounding it.

If the load switch forms a contact arrangement from two parallel contact zones, the current load is divided.

A particularly space-saving construction is achieved with a large stroke of the switch contacts in that the contacts of the circuit breaker are formed on the one hand by a terminally bent extension of a foot contact of the fuse base designed as a rail and on the other hand by two adjacent swivel arms which are bent towards one another at their free end, whereby the swivel arms at the base the terminal for the power supply are articulated. In their interior, they can each accommodate a compression spring, which is supported on its other side against the housing of the fuse switch.

If the connection terminal for the power supply is of a saddle roof shape and rectangular in plan in side view, thick conductors can be clamped under the saddle and thin conductors transverse to the saddle line. Such a connection terminal can be used universally if its clamping piece is arranged such that it can be implemented.

• In Figur 1 ist der Sicherungsschalter bei längsgeschnittenem Gehäuse dargestellt.
• In Figur 2 ist der Sicherungsschalter nach Figur 1 von rechts gesehen, jedoch bei geschlossenem Gehäuse, dargestellt.
• In Figur 3 ist der Sicherungsschalter nach Figur 1 im ausgeschaltetem Zustand und bei entferntem Sicherungseinsatz wiedergegeben.
• In Figur 4 ist der Sicherungsschalter nach Figur 1 von links gesehen, jedoch bei geschlossenem Gehäuse, wiedergegeben.
• In Figur 5 ist der Sicherungsschalter nach Figur 1, jedoch bei geschlosenem Gehäuse, von oben gesehen dargestellt.
• In Figur 6 ist der Sicherungsschalter nach Figur 3 nach einem Schnitt längs VI-VI wiedergegeben.
• In Figur 7 ist eine Schraubkappe in Seitenansicht darge-, stellt.
• Figur 8 gibt die Schraubkappe nach Figur 7 im Längsschnitt wieder.
• In Figur 9 ist die Aufsicht auf die Schraubkappe nach Figur 7 dargestellt.

The safety switch according to the invention is to be explained in more detail with reference to an exemplary embodiment shown schematically in the drawing:

• In Figure 1, the fuse switch is shown with a longitudinally sectioned housing.
• In Figure 2, the fuse switch of Figure 1 seen from the right, but with the housing closed.
• FIG. 3 shows the fuse switch according to FIG. 1 in the switched-off state and with the fuse insert removed.
• In Figure 4, the fuse switch of Figure 1 is seen from the left, but with the housing closed.
• FIG. 5 shows the safety switch according to FIG. 1, but with the housing closed, viewed from above.
• In Figure 6, the circuit breaker of Figure 3 is shown after a section along VI-VI.
• In Figure 7, a screw cap is shown in side view.
• Figure 8 shows the screw cap of Figure 7 in longitudinal section.
• FIG. 9 shows the top view of the screw cap according to FIG. 7.

The fuse switch according to FIG. 1 contains a load switch 1 and a fuse 2. A fuse link can be arranged between a head contact covered by the screw cap 3 and a foot contact 4 of a fuse base. The head contact in the screw cap is additionally covered by a flap 5. In the open position of the flap 5, according to FIG. 3, it is locked against being switched on again when the fuse insert 6 is removed, since the magazine 7 engages behind a stop 8 according to FIG. 3 with a nose.

By means of the magazine 7 made of high-temperature-resistant material, the contact 4 will be raised in the direction of the imaginary connecting line 10 to the head contact under the action of the spring 9. The foot contact 4 can be firmly connected to the magazine 7.

The load switch 1 has such an arrangement of the contacts or contact pieces 12 and 13 that the imaginary connecting line 11 of its contacts to the connecting line 10 of the head and foot contact of the fuse base is inclined. The flap 5 closes off at the side and prevents access to the screw cap 3. The contacts with the contact pieces 12 and 13 are suddenly released via a mechanism 14 in the manner of a toggle lever, particularly when switched on. In the embodiment, the knee lever essentially formed by two flap legs 15 to be presented arranged one behind the other to the plane of the drawing and two switching legs 16. The flap legs are articulated on the axis 17. The switching legs 16 are each connected in an articulated manner to connecting legs 19, which act on two pivot arms 21 about the fixed axis 20. In the exemplary embodiment, the load switch 1 has a contact arrangement comprising two parallel contact zones, one of which can be seen in the drawing: namely the one with the contact pieces 12 and 13.

The contacts of the circuit breaker are formed, on the one hand, by a terminally bent extension of the foot contact 4, which is designed as a rail, of the securing base, and, on the other hand, by two adjacent pivot arms 21, which are bent towards one another at their free end. The pivot arms 21 are hinged to the base 22 of the terminal 23 for the power supply. In their interior, they each take up a compression spring 24, which is supported on its other side against the housing 25.

The terminal 23 provided for the power supply is of a saddle roof shape in side view according to FIG. 2 and is rectangular in plan. Thick conductors can be clamped under the saddle and thin conductors can be clamped across the saddle, i.e. in the drawing plane according to FIG. By appropriately shaping the housing, the clamping piece of the connecting terminal can be implemented in the connecting plane by 90 °.

The helical spring 26 with extended and fork-shaped ends on the one hand lifts the switching leg 16 and thus holds the flap 5 in the closed rest position. On the other hand, the coil spring 26 causes a contact pressure between the legs of the base 22 of the connection clamp 23 and the swivel arms 21. The base 22 of the connecting terminal and the swivel arms 21 are made of electrically conductive material, while the hinged legs 15 and switching legs 16 are made of insulating material. The contact pressure between the contact pieces 12 and 13 of the contact arrangement of the circuit breaker is ensured in each case by the contact spring 24 designed as a compression spring.

If the flap 5 is opened with the fuse link 10 screwed in, the position in FIG. 3 is reached in the load switch. In contrast, the magazine 7 and the contact spring 4 initially retain their position according to FIG. 1. If one unscrews the screw cap 3 by means of its handle 30 with its threaded sleeve 31 from the threaded eyeglasses 32, the fuse link 10 is lifted up under the action of the spring 9. When the screw cap is removed, the fuse link can be removed from the screw cap. The threaded goggles 32 are connected to the terminal 33 for the current outlet in a stationary manner.

When the fuse link is screwed in, the current is carried from the connecting terminal 23 via the swivel arms 21 to the foot contact 4 through the fuse link to the head contact in the screw cap via the threaded sleeve 31 to the threaded eyeglass 32 and from there to the outgoing terminal 33.

When the flap 5 is open, the load switch is open, as can be seen in principle from FIG. 3. If you remove the fuse link from the magazine 7, it is raised until it engages behind the edge 8 of a flap 5 of the flap 5 and thereby locks the flap 5 against being switched on again until a fuse link is screwed in. When screwing one Fuse insert, the magazine 7 is moved downward from the position according to FIG. 3 into the position according to FIG. 1. The action of the spring 9 ensures sufficient contact pressure with the fuse insert. The magazine 7 of the fuse base can accommodate fitting elements in the usual way to ensure that only fuse links of a certain nominal current can be used.

The housing 25 can be formed from two similar shells 40, as can be seen from FIGS. 2 and 4. The housing shells can be held together by rivets 41. The flap 5 is articulated on the fixed axis 18. The movable axis 43 forms the knee of the toggle lever for the load switch.

When the fuse switch is switched on after a fuse link has been inserted, a molded nose 50 according to FIG. 3 lies against the flank 51 of the flap leg 15 after a short free travel and lifts the axis 43 about the stationary axis 18 and out of the knee position, as a result of which the switch legs 16 raise the axis 52 and pivot the pivot arms 21, so that the contacts are closed under the action of the contact springs 24 of the circuit breaker.

From the contacts of the load switch 1, a ventilation channel 53 leads past the magazine 7. In the exemplary embodiment, it is connected to the outside air via a ventilation slot 54.

The structure described enables a compact, low fuse switch that can be snapped onto device mounting rails like other installation devices.

For this purpose, the housing has lugs 55 and 56, the lug 56 being a sprung sheet metal part, a so-called slide.

The screw cap 3 according to FIG. 7 has a handle 30 and a threaded sleeve 31. The handle 30 of the screw cap forms grip ribs 60 and rib-shaped depressions 61 on its outer edge, which are drawn over rounded edges 62 up to the front side close to the viewing window 63 according to FIG. This allows the screw cap to be gripped and operated easily.

The viewing window 63 according to FIG. 8 can be used to check whether the fuse link has responded and should therefore be replaced.

The lens 63 is clamped between the handle 30 of the screw cap and the threaded sleeve 31 firmly connected thereto. If the threaded sleeve 31 to the viewing window 63 forms a bottle-neck-like attachment according to FIG. 8, the dropped indicator sheet can be reliably received after the fuse link has responded. This ensures a safe display and prevents the indicator leaflet from falling into the fuse switch when it is replaced. The flanks 64 of the bottle neck-like narrowing of the threaded sleeve 31 form the head contact of the fuse.

Claims (9)

1.Low-voltage load switch with fuse, hereinafter referred to as a fuse switch, whose fuse link is arranged between an additional head contact covered by a flap and a foot contact of a fuse base, in whose power supply a load switch coupled to the flap is arranged, which is locked in the open position without a fuse link , characterized, a) that the foot contact (4) is raised in the direction of the imaginary connecting line (10) to the head contact under spring action (spring 9) by means of a magazine (7) made of high-temperature resistant material, b) that the load switch (1) has such a contact arrangement (contact piece 12, 13) that the imaginary connecting line (11) of its contacts to the connecting line (10) of the head and foot contact of the fuse base is inclined and that the flap (5) laterally locks and suddenly releases the contacts via a mechanism (14) in the manner of a toggle lever, c) that a vent channel (53) is guided past the magazine (7) from the contacts of the load switch (1). 2. Safety switch according to claim 1, characterized in that the head contact is arranged in a known manner in a screw cap (3) made of handle (30) and threaded sleeve (31), which, however, between the handle (30) of the screw cap (3) and the threaded sleeve (31) firmly connected thereto clamps a viewing window (63) so that it cannot be removed. 3. Safety switch according to claims 1 and 2, characterized in that the threaded sleeve (31) to the viewing window (63) forms a bottle neck-like approach (Figure 8). 4. Safety switch according to claims and 2, characterized in that the handle (30) of the screw cap (3) forms on its outer edge grip ribs (60) and depressions (61), the rounded edges (62) close to the front side are drawn to the viewing window (63). 5. Safety switch according to claim 1 and one of claims 2 to 4, characterized in that the magazine (7) is formed from ceramic material. 6. Safety switch according to claim 1 and one of claims 2 to 5, characterized in that the handle of the screw cap is matched in its height to the existing between the switch-on and switch-off position of the fuse base so that it forms a trough-shaped edge surrounding it (70). of the housing is always in a column-tight connection. 7. Safety switch according to claim 1 and one of claims 2 to 6, characterized in that the load switch (1) forms a contact arrangement from two parallel contact zones (Figure 6). 8. Safety switch according to claims 1 and 7, characterized in that the contacts of the load switch (1) are formed on the one hand by a terminally bent extension of a foot contact (4) of the securing base, which is designed as a rail, and on the other hand by two adjacent swivel arms (21) which are bent towards one another at their free end, the swivel arms (21) on the base (22) of the connecting terminal (23 ) are articulated for the power supply and each receive in their interior a contact spring (24) which is supported at its free end against the housing (25). 9. Fuse switch according to one of claims 2 to 8, in which at least the terminal provided for the power supply in side view is gable roof and rectangular in plan, characterized in that the clamping piece of the terminal (23) is arranged implementable.

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