NL1009911C2 - Electrical circuit breaker incorporates fuse element and thermal cut-out switch is compact and easy to maintain - Google Patents

Abstract

The circuit breaker (1) has a fuse element (5) which is connected between two terminals (3, 4). The fuse element (5) is retained between its contacts (9, 10) by a spring (16). Contact between the fuse and the input and output conductors (22, 23) is via pairs (9, 10 and 11, 12) of contacts. If the fuse becomes too hot, a bi-metallic element (21) will bend, releasing a catch (20) and allowing a spring (19) to force the fuse carrier and contact strips (18) to spring up, breaking the circuit.

Description

Safety load switch.

The invention relates to a safety load switch, comprising a safety load switch housing, a holder for receiving a safety element, a switch-disconnector with at least two pairs of contacts and two connection terminals for accommodating the safety load switch in a phase path, which holder is provided with first and second holder contacts which can cooperate with protective element contacts, the first of which is connected to the first terminal via the first contact pair of the switch-disconnector and the second of which is connected to the second connection terminal via the second contact-pair of the switch-disconnector, first holding position and a second holding position is slidable in the safety load switch housing and thereby controls the switch-disconnector such that in the first holding position the first and second contact pairs of the switch-disconnector are in the closed position and in the second holding position the first con The pair of contacts of the switch-disconnector is brought into the switched-off state, wherein during the shifting of the holder from the first holder position to the second holder-position, the second contact pair of the switch-disconnector is brought into the switched-off state and wherein the holder is further removed from the second position. safety load switch housing can be moved up to a safety element changeover position.

European patent application EP 0017815 A discloses a safety load switch, wherein a safety element in the form of a cartridge is received in a holder or magazine, which can be pulled upright from the housing of the switch. A switching operation is hereby carried out, the cartridge being separated on one side from the terminal of the switch. In the extended position of the magazine, this is pivotable, whereby after the pivoting movement of the magazine the cartridge on the other side is separated from the other terminal of the switch. The cartridge can then be taken out of the magazine and changed.

This known switch has the drawback that contact or staple contacts are used, so that the switch is less short-circuit proof. In addition, a litz wire connection is used between a movable and a non-movable part, which makes the switch vulnerable and susceptible to malfunction.

British electric patent 777,849 discloses an electrical switch, which is provided with fixed contacts 13 and 14 and movable contacts 17 and 18 which cooperate therewith. The switch is further provided with a holder 16 for receiving a safety cartridge 20. This holder 16 further supports the contacts 17 and 18. The holder is slidable between a first position and a second position, wherein in the first 5 position the contacts 13 and 14 abut the contacts 17 and 18 respectively. In the second position of the holder, said contacts are separated. The holder 16 can finally be brought into a third position, which is completely pulled out of the housing of the switch. In this third position, the safety cartridge 20 can be changed completely safely.

The object of the invention is to provide a safety load switch of the type mentioned in the preamble, wherein the above-mentioned drawbacks are avoided and wherein the safety, reliability and, in particular, the ease of operation are further increased. According to the invention, this object is achieved in that the outwardly directed side of the holder is provided with an operating button which can be folded out in the security element change position.

This achieves the advantage that the safety element is increased when it is changed by the two-sided or double separation of the safety element. After all, immediately upon leaving the first holding position, the safety element is separated on both sides from the terminals of the safety load switch,

Furthermore, the advantage is achieved that only the operating button is pivotable and that the security element is therefore easily accessible for changing it with little space required.

Advantageous embodiments are described in the subclaims.

The invention will be explained in more detail below with reference to the drawings. In the drawings show:

Figure 1 shows a principle embodiment of the safety load switch according to the invention in the switched-on state;

Figure 2 shows a bottom view of the safety load switch according to figure 1; Figure 3 shows the safety load switch according to figure 1 in the second position, the off position;

Figure 4 shows the safety load switch according to figure 1 in the switch position;

M

1 Figure 5 shows the safety load switch shown in Figure 3 with the operating device folded out 1009911 3; and

Figure 6 shows a preferred embodiment of the invention with exploded parts.

The invention will be elucidated on the basis of a safety load switch in the form of a cartridge load switch. A cartridge load switch is a combination of a switch-disconnector, with which the load can be switched and separated, and an overcurrent protection or fuse or cartridge.

Basic principles for a good cartridge load switch are: 1. Safety: it must be possible to change a cartridge in a touch-safe manner, so when changing a cartridge the contacts must be voltage free.

1.1 Changing the lock: a cartridge must not be changed with the switch-disconnector in the on position.

1.2 Switching on the lock: it must not be possible to switch on the switch-disconnector without a cartridge.

15 1.3 Zero interrupt: the switch-disconnector not only interrupts the phase, but also the zero for maximum safety. This is mandatory in the Netherlands.

1.4 Interchangeable terminals: there is no difference between input and output terminals to avoid mistakes.

2. Operational reliability: the cartridge load switch must function correctly and safely under all circumstances.

2.1 Moment-in: the speed of switching is independent of the person operating the switch, to prevent unwanted burning-in of the switch contacts.

2.2 Appropriate Contacts for Separation: There are appropriate contacts for separation, so do not use the contact surfaces of the cartridge.

2.3 Short-circuit proof: the cartridge load switch is short-circuit proof, ie the contacts do not weld.

2.4 Heat resistant: despite the smallest possible dimensions, the heat of the cartridge must be properly dissipated, the cartridge load switch must not overheat.

2.5 Thermal protection: there is an optional thermal protection, which responds when the cartridge threatens to become too hot during overload.

1009911 4 3. Ease of operation: mounting the cartridge load switch, switching the switch-disconnector, changing a (hot) cartridge must be easy to carry out.

3.1 Status indication: the status of both the cartridge (burnt out or not) and the switch-disconnector (5 on or off) must be clearly visible.

3.2 Pattern Deviation Tolerant: The cartridge holder must be able to accommodate tolerances in the dimensions of the cartridges.

3.3 One operating device: all operations can be performed with a single operating device.

The safety load switch according to the invention meets all the above-mentioned basic principles, in particular the exchangeable connection points realized by double or two-sided separation of the melting cartridge.

Figure 1 shows only schematically an embodiment of a safety load switch according to the invention.

The parts of the safety load switch 1 are housed in a safety load switch housing 2. In said housing 2 there are connection terminals 3 and 4, by means of which the safety load switch can be received in a phase path to be protected. The cartridge 5 is received under mechanical tension and clamped between the holder contacts 6 and 7. The safety load switch 20 further comprises a switch-disconnector 8 consisting of the contact pairs 9, 10 and 11, 12 respectively. Via the contact pairs 9, 10 and 11, 12 the cartridge 5 incorporated in a chain between the terminals 3 and 4. The holder contact 6 is fixedly mounted on a holder (not shown), while the holder contact 7 is slidably mounted on the said holder in a direction to and from the holder contact 6. The staple holder shown is again attached to operating button 13. This operating button 13 engages with a locking lug 14 behind the housing edge 15 and since this operating button is connected to the holder (not shown), the holder contacts 6 and 7 and thus the cartridge 5 clamped between them the drawn position. The spring 16 is fixed at one end relative to the holder, while the other end rests on the projection 17, which is connected via the strip 18 to the holder contact 7. Because the holder contact 7 and the strip 18 are slidably supported on the holder (not shown), under the influence of the spring 16 the cartridge 5 will be clamped with a predetermined contact pressure between the holder contacts 6 and 7 to ensure sufficient contact force. In this connection, the pre-tension and characteristic of the spring 16 must be chosen such that at minimum cartridge length the tension force is the minimum required value. Of course, the tension will increase slightly with larger cartridge lengths. In order to avoid unnecessarily high clamping forces, the aim should be a relatively flat spring characteristic, which implies the use of a relatively long tension spring. It is clear that due to the displaceability of the holder contact 7 and the tensioning force of the spring 16, compensation of pattern length tolerances is achieved.

In the position of the cartridge load switch shown in figure 1, the cartridge is received via the pairs of contacts 9, 10 and 11, 12 in the phase path which is connected to the terminals 10 3 and 4.

The contacts 9 and 12 are located at the free ends of the L-shaped strips 22 and 23, respectively, which are connected to the terminals 3 and 4, respectively.

When a separation is to be effected in the phase path, the operating knob 13 in the figure is moved to the right, so that the latch 14 is released from the housing edge 15. Under the influence of the spring 19, the holder is not shown in detail of the cartridge 5 and thus the operating button 13 is pressed in an upward direction, until the latch 20 engages behind the housing edge 15. In this so-called off position, which position is shown in figure 3, the switch-disconnector is in the switched-off state, wherein the contacts 9, 10 and 11, 12 of the associated contact pairs are separated from the switch-disconnector, so that a two-sided separation of the pattern 5 has arisen; in other words, the holder contacts 6 and 7 are both separated from the phase path connected to the terminals. Thus, an optimally safe condition with regard to contact of the cartridge 5 has been achieved. It should also be noted that the detailed version of the support of the spring 19 is not shown, but any expert will be able to find a suitable solution for the proper functioning of the spring 19. In the reverse direction, when the cartridge 5 has to be returned to the phase path included, the control knob 13 is pressed toward the housing, the spring 19 acting as a momentary spring between the holder and the safety load switch housing. 30 The safety load switch can optionally be equipped with a thermal protection. It comprises a passive bimetal element 21. Under high load, i.e. overheating of the cartridge 5, the bimetal element will deform and be biased such that the control knob 13 is pressed to the right and the 100991 * 6 bimetal element 21 has undergone the bending shown in figure 3. and the operating button 13 and the holder with the cartridge 5 are driven out under the influence of the moment-spring and the cartridge is separated on two sides. The phase path connected to terminals 3 and 4 is then interrupted. The cartridge can only be incorporated in the phase path after the temperature has dropped sufficiently and the bimetal element 21 has almost reached the stretched state again. This is important for saving the cartridge and an indication that there is an overload (so no short circuit).

In Fig. 2, in addition to the connection terminals 3 and 4 and the strips 22 and 23, there are also 10 connection terminals 24 and 25, as well as the L-shaped strips 26 and 27 connected thereto. The connection terminals 24 and 25 serve to accommodate the switch. a neutral. The free ends of the strips 26 and 27 are provided with contacts 28, 29 which, depending on the position of the holder of the cartridge 5, are connected or separated from each other via a loop fixed on the holder.

The neutral conductor interruption is thus also controlled here by sliding the holder of the cartridge 5.

When the cartridge 5 is to be changed, after the phase path has been separated (see figure 3), the control knob 13 in figure 3 must be moved to the right, so that the latch 20 is released from the housing edge 15 and the control knob 13 further out of the housing 2 g 20 can be drawn to the position shown in Figure 4. The cartridge 5 is now now visible ad and to change this cartridge 5 the operating button 13 is folded out to the position shown in figure 5. The operating button 13 is provided with means which, when folded out, release the pre-tension of the holder contact 7. This means is schematically shown in figure 5 as cam 30, which presses against the projection 17 of the strip 18 connected to the holder contact 7. The spring 16 is then compressed and the clamping of the cartridge 5 is released, making the cartridge 5 easy to take out.

The safety load switch according to the invention is thus very easy to operate. There are 3 control knob positions: 1. The control knob 13 is fully pressed in and the switch contacts of the switch-disconnector are closed, while the holder remains locked by means of the latch 14 on the control knob within the housing, as does the cartridge 5.

] 2. The push button is extended by a distance of, for example, 10 mm and the 1009911 7 contacts of the switch-disconnector are open. The cartridge 5 is still invisible behind the operating button 13. The safety load switch manifests itself in these two positions as a welding switch with push button operation.

3. In this position, namely the switch position, the holder is extended over the maximum sliding length, whereby the knob can be folded out. During this folding-out or tilting movement, the cartridge is first relieved between the holder contacts and then tilted upwards with its rear side, in order to inspect it further and, if necessary, to change it.

From the said switch position, the operating button can be tilted back, the cartridge 5 being re-tensioned and the holder being pushed through the second position to the first position, which positions are defined by the latches 20 and 14, respectively.

The holder runs along the path from the first to the second position of the operating button 13 against a flat leaf spring, which first buckles in S-shape after the increase of the operating force and, after progressive compression, switches to a buckling mode with only one buckling field, causing the spring force to decrease drastically. The now buffered spring energy in the operator's body parts will accelerate the cassette to ensure a minimum switch-on speed. The "moment-m" function thus achieved is important for safe short-circuit switching; after all, the switching operation is completed independently.

When switching off, the said leaf spring must have sufficient residual tension to expel the holder again over the path from the second to the first position of the operating button 13. This switching-off movement is obtained by pressing the top edge of the button down and to the right such that the locking edge is released and the holder with operating button can be pushed out unobstructed to the position 2, in which the locking 20 engages behind the housing edge 15.

As can be seen from Figures 1-5, the contacts 9, 10 and 11, 12 are sliding contacts, the sliding surfaces of each pair of contacts 9, 10 and 11, 12 respectively extending parallel to the sliding direction of the holder and operating button 13.

Because the sliding movement of the holder and the operating button is used to initiate and control the switching function of the switch-disconnector, a contact configuration of sliding contacts can be applied in a simple and advantageous manner. Preferably double sliding contacts are used, with the following 1009911 8 advantages: low retraction force level with regard to operation self-cleaning insensitive to cartridge length tolerances 5 - short-circuit proof configuration.

Figure 6 shows a preferred embodiment of the safety load switch according to the invention with disassembled parts.

The container 31 is shown at the bottom left, while the housing 32 is at the top right - illustrated.

The carriage 33 is the basic frame of the holder 31 and is provided with laterally slotted receiving cavities 34 and 35 for the copper webs 36 and 37. The copper webs are captively locked laterally, because they are, as it were, visible over a tab are slid, relying on the elastic deflection of these copper webs. The copper strips 36 and 37 are also enclosed in an axial sense. The copper track 38 can move axially relative to the slide 33 and is driven by the tension spring 39 to an end position. This tension spring 39 mounted under bias will move the copper web 38 toward the actuator knob 40 to clamp the cartridge between the cartridge holder contacts 41 and 42. In the end position of the copper web 38, the distance between the cartridge holder contacts 41 and 42 is less than the smallest possible manufacturing size of the cartridge.

The operating button 40 is provided in its inner cavity with "recording forks", not shown, which snap over the axle journals 43 and 44 of the carriage 33. The operating button 40 and the carriage 33 are thus connected together in a captive manner and the operating button can be moved over the axle journals 43 and 44 rotate between the positions schematically shown in Figures 4 and 5. In Figure 5 a cam 30 is schematically shown, which can slide the copper web 38 against the spring pressure of the spring 39 of the operating knob 40, whereby the clamping force on the cartridge is reduced and is dropped in the tilt end position of the control knob 40. The cam 30 can be shaped in such a way that the cartridge is fully exposed in the fully unfolded position of the operating button 40 and can be easily removed for checking. or exchange.

The holder is further provided with a calibration element 45 to define the maximum allowable cartridge size. The calibration element 45, shown separately here, functions as it were as a "gate", the inner opening of which the head of the maximum permitted cartridge can enter, so that the contact can be made with the contact surface 42 of the copper web 38. Thus it is prevented that oversized cartridges 5 can be used. Naturally, the calibration element can also form an integral part of the holder.

The container is considered as a sub-composition, which may or may not be an integral part of the cartridge load separator. If the holder is to be captive, the complete holder can be mounted in the housing 32, 10. The housing 32 consists of two housing halves 46 and 47 provided with conductors 48 to 51 and the bus terminals 52 to 53. The bus terminals 52 to through 55 can be slid over the ends of the phase conductors and the neutral conductors. The lateral locking within the housing halves of the said parts can take place by having them click over a "cam", using the elasticity of the parts concerned or by using an intermediate piece which is herein referred to as a partition.

When joining the two housing halves 46 and 47, the following parts must be included: the divider 56 (if used) 20 - the holder 31 the moment-spring 57 the rail clicker 58, and the bimetal (optional) not shown in Figure 6 .

The housing halves are preferably mutually fastened by means of clicks (not shown).

It should also be noted that far-reaching compactness in construction width is now possible since the cartridge no longer has to be incorporated in the well-known ceramics, rosette (as holder) and that all operations (switching, separating and exchanging) can be carried out by one operating element.

Conclusions ...

100991 ή

Claims (8)

1. Safety load switch, comprising a safety load switch housing, a holder for receiving a safety element, a switch-disconnector with at least one. two pairs of contacts and two terminals for accommodating the safety switch in a phase path, which holder is provided with first and second holder contacts which can cooperate with safety element contacts, the first of which is connected to the first terminal via the first contact pair of the switch-disconnector and the second of which is connected via the second contact pair of the switch-disconnector to: the second connecting terminal, wherein the holder is slidable between a first holding position and a second holding position in the safety load switch housing and thereby controls the switch-disconnector such that in the first holding position the first and second . contact pairs of the switch-disconnector are in the closed state and that in the second holding position the first contact pair of the switch-disconnector is brought into the switched-off state, wherein during the shifting of the holder from the first holding position to the second holding position the second contact pair of the switch-disconnector is brought into the switched-off state and wherein the holder is slidable further than the second position out of the safety load switch housing into a safety element change-over position, characterized in that the outwardly facing side of the holder is provided with a safety element in the safety element. -change position folding control button. 2. Safety load switch according to claim 1, characterized in that the holder contacts are biased towards each other and the control knob is provided with means which release the pre-tension when the control knob is unfolded. Safety load-break switch according to claim 1 or 2, characterized in that the contacts of the switch-disconnector are sliding contacts, the sliding surfaces of each pair of contacts extending parallel to the sliding direction of the holder. 4. Safety switch-disconnector according to claim 3, characterized in that at least one of the contacts of the contact pairs of the switch-disconnector is a sliding contact. j Safety load switch according to one of Claims 1 to 4, characterized in that the holder comprises a slide which can be slidably mounted in the safety load switch housing, that the first holder contact is fixed to the slide and that the second holder contact to and from the first holder contact is slidably mounted on the carriage and is biased by means of a spring in the direction of the first holder contact. Safety load switch according to any one of claims 1 to 5, characterized in that a "moment-in" spring is arranged between holder and safety load switch housing. Safety load switch according to any one of claims 1-6, characterized in that a neutral conductor interruption is controlled by sliding the holder. 8. A safety load switch according to any one of claims 1-7, characterized in that the holder is provided with a lock for releasing the holder releasably in the first holder position in the safety load switch housing and that a bimetal element is provided which exceeding a predetermined temperature releases the lock. TO09911