EP0849764B1 - Fuse-holder for apparatus - Google Patents

Abstract

The electrical fuse holder has a main body that is cylindrical Ä3Ü with a stepped top end that locates against the surface of a mounting panel Ä2Ü. The body is produced in plastic and has a bore to receive an insert Ä4Ü. The fuse Ä5Ü is located in the bore and one end engages a fixed contact Ä7bÜ while the other is engaged by a coil spring contact Ä6Ü that extends into a connecting lead Ä7aÜ. Both the main body and the insert are formed with a series of axial air ventilation channels. An alternative body has a perforated section

Description

The present invention relates to a device fuse holder, consisting of a lower part and an insert carrier, which are made of a thermoplastic.

Colloquially, the lower part is also used as a holder, and the Insert carrier also referred to as a cap. Here, however, is on the terms lower part and insert carrier.

Such device fuse holders are in electrical devices widespread. They wear in one by the bottom and the insert formed space interchangeably a securing element, often a tube fuse. The device fuse holder connects the fuse element in an electrically conductive manner with his external contacts. Depending on the embodiment is a Device fuse holder can be used on circuit boards, or it is designed for installation in housings of electrical devices. Common to all also known embodiments, that the device fuse holder over the fuse element should make its external contacts electrically accessible, whereby the fuse itself is isolated as well as possible from the environment should be. Because of their good insulation properties and the good processability are thermoplastics in the mass production of device fuse holders preferably used.

Device fuse holders are approved in a standardized procedure, inter alia by simulating the thermal load on a fuse element by means of an equivalent resistor in continuous operation. The fuse power loss P _v is measured at 1.5 times the nominal current of the fuse element, but a fuse does not switch off immediately even at higher currents. Thus, over a period of time, much higher power losses than the specified standard power loss P _v can be delivered from a fuse to a holder. Combinations of operating states occur with fuse-fuse holders that are not taken into account in the standard. In this way, even when the device fuse holder and fuse element are compiled in accordance with the standards, thermal overloading of the holder can be caused in continuous operation, for example with a choice of 1.8 W fuse power loss and 4 W maximum thermal load of the device fuse holder. Due to an oversized total thermal load, the thermoplastic body of the device fuse holder can melt or scorch despite being formally correct.

DE-A-942821 shows a holder for a fuse link, which is installed in control panels. The holder is there from a lower part and a cap made of plastic exist and have fireproof porcelain inserts. In the walls, especially in the base area, are ventilation openings provided so that air flows parallel to Form central axis and can cause cooling.

It is an object of the invention to provide a device fuse holder of the above kind to create the simple way sufficient cooling enables without additional sources of danger to accomplish.

• Unterteil und Einsatzträger aus einem thermoplastischen Kunststoff hergestellt sind
• und die Lüftungsschlitze in der Wandung des Unterteils so verlaufen, daß
• der Innenraum des Geräte-Sicherungshalters vollständig geschlossen ist,
• wobei die Lüftungsschlitze (8) parallel oder senkrecht zu einer Mittelachse (9) des Sicherungshalters (1) verlaufen
• und die Wandung derart durchsetzen, daß sich durchgehende Luftströmungen bilden können.

The object is achieved in that

• Lower part and insert carrier are made of a thermoplastic
• and the ventilation slots in the wall of the lower part run so that
• the interior of the device fuse holder is completely closed,
• wherein the ventilation slots (8) run parallel or perpendicular to a central axis (9) of the fuse holder (1)
• and penetrate the wall in such a way that continuous air currents can form.

Due to the arrangement of ventilation slots in the walls of the lower part and, if applicable, also of the wearer entire contact area of the device fuse holder with the Ambient air increased. This can be increased in Power loss generated inside the device fuse holder be delivered.

The functions of the Fuse carrier and that of a closure for the lower part combined in one part. The invention with all of it further developments is of course also for device fuse holders executable where the fuse carrier with the lower part is connected, or the fuse carrier as independent, single part is executed.

Advantageously, the ventilation slots enforce the Device fuse holder parallel or perpendicular to it Central axis and run in the wall such that can form continuous air currents. So chimney-like Ways created to thermally fuse the device to relieve that by the total power loss warmed up air discharged from the device fuse holder and cool air can flow in from the surroundings.

In one development, the ventilation slots only pass through the lower part of the device fuse holder. The interior of the Device fuse holder remains self-contained and thus electrically insulated from the environment.

In accordance with a further inventive idea, such Device fuse holder that regarding the installation position on the part of the lower part within a device equipped with an enlarged surface. That kind of pure surface enlargement in turn requires an increased Power dissipation through the surrounding air by convection.

In an advantageous development, the surface of the Lower part of the device fuse holder by sliding it on and / or locking and / or screwing on a sleeve can be enlarged.

Special advantages when deriving thermal losses is a metallic sleeve described in the above Way placed outside on the plastic body of the lower part becomes. For example, a hole for receiving a device fuse holder according to the invention comparatively be kept small because the lower part itself has a small diameter. Plastic is also used in the Injection molding saved.

The metallic sleeve is placed on or over the lower part and conducts the heat loss coming from the lower part due to the better thermal properties compared to plastics from metal also better. The transition point between Plastic and the metal can, for example, by close contact or by applying thermal grease well designed to be thermally conductive.

A device fuse holder according to the invention is advantageously designed so that it is in a receiving hole Mounting plate of a device can be used. So can, above all in conjunction with the sleeve described above on the inside Part of the lower part, a simple type of attachment to provide. Further advantageous fastening measures are described below.

In an alternative approach according to the invention for the mentioned task becomes a device fuse holder from one thermoplastic made so that the lower part is connected to at least one heat-dissipating element.

According to claim 7, the heat-dissipating element is in one piece connected to the lower part of the device fuse holder. The one-piece connection results in a good heat transfer of the lower part on the heat-dissipating element and minimized at the same time the number of individual parts when using such Device fuse holder.

In a further development, the heat-dissipating element snaps into place for fastening the device fuse holder in a wall of a housing. It therefore fulfills the pure cooling function also the tasks of a holding and fastening means.

Such a device fuse holder is preferably manufactured in such a way that the heat-dissipating element and the electrical Contacts before potting with a thermoplastic are integrally connected, preferably in Form of an endless band made of metallic stamping material consists. The strip material is fed to the injection molding machine and by bending and / or folding into a predetermined shape brought. After casting and hardening of the plastic the metallic parts have different functions from each other Cut. This prevents, for example cooling metal parts as well as the contacts are live when used.

The separation is particularly advantageously carried out in a combined one Working step when spreading the injection molds, in which the lower part of a device fuse holder according to the invention will be produced.

According to claim 12, the device fuse holder is in one Mounting plate from the back to the front can be installed, i.e. in reverse of the normal installation direction. For this purpose, the heat-dissipating element is preferably in Form of a spring part clamped at least on one side educated. The particularly metallic element can be used as bent wire, or as a sheet metal part. So in addition to heat dissipation, it can also be automatic and free of wobbles Attachment can be realized. The heat dissipating must Element not installed on the outside after installation Front board of the device must be visible. A preferred embodiment is based on a sketch of an embodiment described.

The described "back-to-front" assembly hides the essential Advantage in itself that all connections are already in the pre-assembly has also been attached to the device fuse holder could be. So an electrical circuit as a complete Module completed and possibly even already tested Unit installed in a housing of an electrical device become. This allows many workflows to be deployed a device fuse holder according to the invention with simultaneous Streamlined reduction of working hours become.

All of the measures mentioned serve individually and also in combinations as constructive measures to upgrade device fuse holders, around them e.g. at higher ambient temperatures while maintaining the known materials can. Device fuse holders according to the invention also have high for all conceivable switching states of fuses Reliability on. In addition, through the realization of Invention features improvement in manufacturing as well as in the Processing easy to achieve.

Fig. 1

eine Schnittdarstellung einer ersten Ausführungsform eines Geräte-Sicherungshalters mit Lüftungsschlitzen;

Fig. 2

eine alternative Ausführungsform zu Fig. 1 in einer Schnittdarstellung;

Fig. 3

eine Schnittdarstellung einer weiteren alternativen Ausführungsform eines Geräte-Sicherungshalters mit Lüftungsschlitzen;

Fig. 4a, 4b

eine Seitenansicht und eine geschnittene Draufsicht eines Geräte-Sicherungshalters;

Fig. 5a, 5b

eine alternative Ausführungsform zu Fig. 4a, 4b;

Fig. 6

eine weitere Alternative zu 4a, 4b;

Fig. 7

einen Längsschnitt durch eine weitere Ausführungsform eines Geräte-Sicherungshalters und

Fig. 8

eine Schnittdarstellung einer weiteren Ausführungsform eines Geräte-Sicherungshalters.

Exemplary embodiments of the invention are explained in more detail below with reference to the drawing. The pictures show:

Fig. 1

a sectional view of a first embodiment of a device fuse holder with ventilation slots;

Fig. 2

an alternative embodiment to Figure 1 in a sectional view.

Fig. 3

a sectional view of a further alternative embodiment of a device fuse holder with ventilation slots;

4a, 4b

a side view and a sectional plan view of a device fuse holder;

5a, 5b

an alternative embodiment to Fig. 4a, 4b;

Fig. 6

another alternative to 4a, 4b;

Fig. 7

a longitudinal section through a further embodiment of a device fuse holder and

Fig. 8

a sectional view of another embodiment of a device fuse holder.

Fig. 1 shows a device fuse holder 1, for insertion formed in a receiving hole 2a of a front panel 2 is. The device fuse holder 1 is not mandatory in use this form, since not all applications use fuses require that must be accessible from the outside. in the The following are only device fuse holders 1 treated in a receiving hole 2a of a front panel 2nd can be used.

In the case shown in FIG. 1, there is a lower part 3 its upper region 3a from the receiving hole 2a of the front panel 2 out. In this area 3a there is an insert carrier 4 in the usual way, for example by means of a Renk screw lock, attached in the lower part 3. This is a security element 5 of a resilient device 6 in the insert carrier 4 recorded, held and electrically with a side contact 7a contacted. A second electrical external contact, a foot contact 7b is located in the lower area 3b of the lower part 3.

Be through the interior of the device fuse holder 1 through ventilation slots 8 ways for a continuous closed Airflow to remove the total power loss created by warmed air. The ventilation slots 8 are distributed on the circumference of the insert carrier 4 such that they than elongated small openings in the neighborhood more exciting Parts in the upper area of the insert carrier housing 4 run. On the bottom part 3 are the ventilation slots 8 arranged analogously, so that here too a direct Contact with live and live parts even when Insertion of needles or the like is avoided.

The electrical contacts 7a, 7b are made by stamped sheet metal parts educated. In a variant not shown here ventilation slots 8 are formed in the lower part 3 in that the electrical contacts 7a, 7b in their central area have an elongated punch opening, which in the lower part 3 serve as channels for air exchange. This measure can alternatively or in addition to the ventilation slots described 8 are used.

The measures mentioned for producing ventilation slots 8 are with little effort in the previous production process, For example, can be integrated into a plastic injection molding process. The ventilation slots 8 run in this example parallel to a central axis 9 of the entire arrangement, so that at least in sections parallel to the recesses for the electrical contacts 7. That's an integration the ventilation slots 8 in an injection mold Maintaining the previous opening and closing movement easy to do.

2 shows an alternative embodiment of a device fuse holder 1 using ventilation slots 8 For the sake of clarity, this is only Lower part 3 with omission of the complete deployment vehicle 4 and the securing element 5 shown. Their arrangement takes place analogously to FIG. 1.

In this embodiment, the ventilation slots 8 run parallel to the central axis 9 only in the wall of the lower part 3. This leaves the interior of the device fuse holder 1 completely closed. The cooling takes place exclusively over the wall of the lower part.

Fig. 3 also represents only a lower part 3 of another alternative embodiment of a device fuse holder 1 represents, here the ventilation slots 8 perpendicular to the central axis 9 run. The ventilation slots 8 are only in the part of the lower part 3 located inside the device. In the manner shown results from increasing the Number of ventilation slots 8 with an open honeycomb structure very good heat dissipation. To the receiving hole 2a of the front panel 2 this honeycomb structure goes into a reinforced section in the Area 10 of the receiving hole 2a over which the actual Fixing of the device fuse holder 1 is preferably carried out. In a known manner, a thread for a union nut can be used here to be ordered. Other mounting options too are discussed below.

4a is a further embodiment of a device fuse holder 1 shown, for the removal of the internally generated Heat loss on the inside part of the lower part 3 has an enlarged surface 10. The enlargement surface 10 increases heat dissipation by convection. The surface 10 on the Bottom part as a one-piece plastic part with ribs rounded edges formed. This results in an overall Mechanically very stable device fuse holder.

Fig. 4b shows a section through Fig. 4a in the plane A-A It demonstrates that by choosing a wavy surface 10 the total area available for heat dissipation clearly compared to a normal state of a smooth or flat surface is enlarged. Inside the wall of the Lower part 3 is the heat generated by the power loss led to the surface 10 by heat conduction, where they are removed by free or forced convection becomes.

The internal structure of such a device fuse holder 1 up to the outer electrical contacts 7 is identical to the element shown in Fig. 1. Of course the measures shown in Fig. 1 also in the embodiment 4a, 4b integrable.

The embodiment of Fig. 5a uses the same principle of Enlargement of the outer surface 10 on the inside of the device Part of the lower part 3 as in Fig. 4a. The becomes Increasing the convection effect, enlarged surface 10 formed by a metallic sleeve 11. The sleeve 11 is in slotted in the axial direction, so that they are made in a simple manner a stamped and then bent sheet metal piece can be. The sleeve 11 can on the lower part 3rd of the device fuse holder 1 pushed on or clipped on be, the sleeve 11 at the same time in addition to the heat dissipation can also take on the task of consolidation. About the in Fig. 5a shown basic structure can also Sleeve 11 still have knobs or the like, which in corresponding Depressions or an external thread of the lower part 3 intervene to create a releasable and durable, non-slipping To form bond. The advantage of using FIG. 5a The embodiment described is that the lower part 3 seen from its diameter narrow builds, so that in a front panel 2 also only one receiving hole 2a Size for this device fuse holder 1 is to be provided.

A metallic sleeve 11 can also be used for retrofitting existing device fuse holder 1 can be used for fastening, as well as to reinforce such a device fuse holder for safe use at higher temperatures or all occurring operating states of the combination from fuse 5 and fuse holder 1.

Fig. 5b shows a top view of the sleeve 11 of Fig. 5a It shows that in analogy to Fig. 4b a further surface enlargement realized by forming ribs has been. In the present case, this measure has a slotted one Sleeve 11 still has the advantage that the spring stiffness the metallic body is adjustable in terms of production technology. This makes such a sleeve 11 in a wide diameter range of fuse holder lower parts 3 can be used. Furthermore, it is not necessary for a sleeve 11 to be shorter than the rear part of the lower part 3, as in Fig. 5a shown. The sleeve 11 can even the connections 7 protrude if the necessary precautions at connections 7 to isolate the connections have been made, such as it is common. This will remove the heat increased by enlarging the sleeve 11 as a heat sink.

6 shows an alternative embodiment of a device fuse holder 1 according to Figures 4a, 4b and 5a, 5b. Here is a nut 12 in its lower area to a sleeve-shaped Shaft 11a shaped. The mother runs towards the upper end 12 into a collar 13. Such a mother 12 will on an external thread (not shown here) of the lower part 3 screwed so that a front plate 2 between the from the Receiving hole 2a protruding upper part 3a of the lower part 3rd and the collar 13 of the sleeve 11 firmly and wobble-proof becomes. To speed up and simplify the fixing process can the external thread on the area near the upper part 3a be limited to the lower part 3. As a measure for further Improvement of the thermal connection between the lower part 3 and the entire sleeve 11 is between the two parts Thermal paste 14 applied, as shown here in Fig. 6 as an example located.

Fig. 7 pursues another approach to deriving the Waste heat. For this purpose, a heat-dissipating is used at two points Element 15 integrally connected to the lower part 3. The heat dissipating Element 15 protrudes into the wall of the lower part 3 in and is there firmly from the plastic material from which the lower part 3 is constructed, enclosed. This results in also an intimate thermal contact with a good transition the heat from the wall into the heat-dissipating element 15 into it. The heat-dissipating element 15 can be a plastic part be integrated in the lower part 3. Because of the essential However, better thermal conductivity is used as the material for a heat-dissipating element 15 prefers a metal. there the heat-dissipating element 15 is at an oblique angle to the Center axis 9 arranged such that it as a resilient element serves and a barb for fastening such Bottom part in the receiving hole 2a of a mounting plate 2. The lower part 3 thus latches through after insertion the receiving hole 2a of the front panel 2 and thus gives easier and quick assembly a permanent and safe Stop.

In terms of production technology, it offers particular advantages if that heat-dissipating element 15 together with the contacts 7 consists of the same metal and also a manufacturing machine fed as a coherent single piece can be. As a manufacturing machine in the production of modern Device fuse holders 1 are used for plastic injection molding machines, the one in a work preparation step Unit of contacts 7 and one or more heat-dissipating Separate elements 15 from an endless band of stamped parts and by bending into a predetermined initial shape and Can bring starting position. The lower part 3 is then called Plastic injection molded part around these metallic parts cast. In a final step, the individual, previously connected parts automatically when Moving the injection mold apart from each other. To the removal of the separated parts 16 are thus the contacts 7 electrically isolated from each other. They are also further heat-dissipating elements 15 neither voltage nor live, since they are safely separated at contacts 7, as can be seen from Fig. 7. In addition to a quick and problem-free assembly also results in a very compact Manufacture of the lower part 3 of a device fuse holder 1.

In Fig. 8 the basic idea for the construction of the lower part 3 of a device fuse holder 1 of Fig. 7 picked up and educated. For this purpose, as in FIG. 7, the heat-dissipating Elements 15 designed as spring arms. At the top Area 3a of the lower part 1, however, arms 17 are in one piece with connected to the lower part 3. These arms 17 are designed that through the overall structure of the lower part 3 itself Assemble the device fuse holder 1 in the opposite direction offers, so a "back-to-front" assembly, in which the lower part 3 from a rear side 18 of a mounting plate 2 the receiving hole 2a inserted through to the front 19 becomes. Due to the spread arms 17, the lower part 3 in rearward direction not pulled out of the receiving hole 2a become. The special shape of the heat-dissipating Elements 15 is used to after snapping the lower part 3 by a resilient bracing of the heat-dissipating elements 15 to guarantee a secure and wobble-free fit. Each heat-dissipating element 15 is shaped so that Wall thicknesses of front panels 2 in a larger area for a secure permanent attachment is suitable. Hence it follows a particularly simple and quick assembly, with a complete Module including a device fuse holder 1 can already be completely prefabricated and tested, to then only be inserted into a housing of an electrical device to become. In addition, the resilient system of the heat-dissipating Elements 15 on the back 17 of the large area Front plate 2 for a good heat transfer and thus one safe heat dissipation. This is how the entire front panel 2 is used as an additional heat sink for those from the device fuse holder 1 heat to be dissipated.

Claims (11)

1. Fuse holder for apparatus

   comprising a base portion (3) and an insert carrier (4),

   in which ventilation slits (8) are disposed in the wall of the base portion (3) and optionally also of the insert carrier (4),

   characterised in that

   the base portion and insert carrier are made of a thermoplastic plastics material

   and the ventilation slits (8) extend in the wall of the base portion (3) so that

   the interior of the fuse holder (1) is completely closed,

   whereby the ventilation slits (8) extend parallel or perpendicular to the central axis (9) of the fuse holder (1)

   and pass through the wall such that continuous air currents can develop.
2. Fuse holder as claimed in Claim 1, characterised in that the ventilation slits (8) pass through only the base portion (3) of the fuse holder (1).
3. Fuse holder for apparatus comprising a base portion and an insert carrier, which are made of a thermoplastic plastics material, characterised in that the base portion (3) has an increased surface area, with respect to the installation position, on the portion situation within a device.
4. Fuse holder as claimed in Claim 3, characterised in that the surface area (10) of the base portion (3) may be increased by pushing on and/or locating and/or screwing on a sleeve (11).
5. Fuse holder as claimed in one of Claims 3 and 4, characterised in that the sleeve (11) is metallic.
6. Fuse holder for apparatus comprising a base portion and an insert carrier, which are made of a thermoplastic plastics material, characterised in that the base portion (3) is connected to at least one heat dissipating element (15).
7. Fuse holder as claimed in Claim 6, characterised in that the heat dissipating element (15) is integrally connected to the base portion (3).
8. Fuse holder as claimed in Claim 6 and/or Claim 7, characterised in that the heat dissipating element (15) locates in a wall of a housing in order to secure the fuse holder (1).
9. Fuse holder as claimed in one of Claims 6 to 8, characterised in that the heat dissipating element (15) and electrical contact (7) are integrally connected together with a thermoplastic plastics material before the moulding process and are subsequently separated, particularly when moving injection moulds apart.
10. Fuse holder as claimed in one of the preceding claims, characterised in that the fuse holder (1) may be inserted in a receiving hole (2a) in a mounting plate (2) of an apparatus.
11. Fuse holder as claimed in one of the preceding claims, characterised in that the fuse holder (1) may be installed from a rear surface (18) of a mounting plate (2) towards the front surface (19).

Images