EP1389341B1 - Clamping auxiliary element - Google Patents

Abstract

The lifting clamp (1) has a rectangular frame (14) and a rectangular box (15) with an upper section (150) positioned between the upper and lower sections (140,141) of the frame and displaced relative to the latter against a resistance provided by the friction between the box and the frame. A clamp screw (16) fits through an opening (142) in the upper section of the frame for engaging a screw thread (152) in the upper section of the box.

Description

The invention relates to a lift clamp for installation in a housing of an electrical appliance, such as e.g. a circuit breaker comprising a rectangular frame and a rectangular box, the upper portion of which is disposed between the upper portion and the lower portion of the frame, whereby the box is slidably supported in the frame, further comprising a clamping screw passing through one in the upper frame. Section incorporated aperture freely rotatably guided and engages in an incorporated into the upper portion of the box thread, wherein the box is held against a resistance displaceable in the frame.

In such lift clamps, electrical lines can be pinched at two locations, namely between the lower portions of the frame and the box (lower receiving space) and between the upper portion of the frame and the head of the clamping screw (upper receiving space).

When turning the clamping screw in the opening direction, the box is first moved down and thus opened the lower receiving space. Only when the box has reached its lowest position, in which it comes to a housing part to the plant, is moved at progressing opening movement, the clamping screw upwards and thus opened the upper receiving space.

When tightening the clamping screw it must first be rotated so far until the lower box section at the lower frame section comes to rest, only then is the rotational movement of the clamping screw in the closing direction in a clamping application of the screw head to the upper portion of the frame or to an intermediate implemented this upper section and the screw head lying electrical conductor.

If only the upper receiving space is used to open this space or for clamping an electrical conductor in this room, the clamping screw must be rotated very far, whereby the time required to connect electrical lines to the lift clamp is relatively high. Such a terminal with terminal boxes is for example from the EP 0168 596 A known. Also from the EP 0 905 839 A goes out such a lift clamp.

Lift clamps are now also known in which a resistor, against which one of the terminal boxes could be displaced, is provided so as to reduce the time required for connecting electrical lines to the lift clamps. In the DE 195 13 281 A , of the DE 2 107 218 A and the EP 1 028 489 A For example, terminal or lift terminals are known in which the resistance against which a box is slidably held in the frame, each realized by a spring. In the EP 0 280 672 A such resistance is accomplished by friction of the box on parts of the housing.

A disadvantage of this prior art is that the resistance against which the box is slidable in the frame, could be overcome accidentally, and so the lower receiving space could be opened early.

It is an object of the present invention to avoid this disadvantage and to provide a lift clamp of the type mentioned, in which when rotating the clamping screw in the opening direction of the first lying between the upper frame section and the screw head receiving space opened, the lower receiving space but provisionally closed. The lower receiving space should only be made by taking special measures, such as Exercise a greater force on the screw, can be opened so as to avoid accidentally moving the box particularly safe.

According to the invention this is achieved in that the resistor is formed by a fixed in the housing, preferably integrally formed with the housing, Abscherzapfen which is positively connected to the box.

When turning the clamping screw is not a large force, i. no more force than is necessary to turn a screw is exercised, this resistance initially prevents a displacement of the box. The opening movement of the screw is entirely in a lifting of the screw head from the upper frame portion, i. in an opening of the upper receiving space, implemented- This allows already after slight rotation of the clamping screw in the opening direction to insert a terminal lug a busbar system in the upper receiving space and clamp it there by slight rotation of the clamping screw in the closing direction there.

When overcoming the resistance, for example by exerting pressure on the clamping screw, the resistance can be overcome, the box moved down and thus the lower receiving space can be opened. In particular, by the Abscherzapfen any displacement of the box relative to the frame is initially avoided, whereby an unintentional movement of the box is particularly safe avoided. A Displacement of the box and thus an opening of the lower receiving space but can still take place after shearing the shear.

It would also be possible for the resistor to be replaced by a spring located below the box, e.g. Coil spring, is formed, which biases the box in the direction of the frame.

The force of a spring decreases only very slightly in the course of time or with frequent compression, in particular by less than the frictional forces prevailing between two frictionally abutting components with frequent frictional movements. This realization variant of the resistor thus has the advantage of a longer service life than those based on friction of two components variants.

The resistance could also be formed by friction of the tab on parts of the housing. Again, it is advantageous that for the formation of the resistor only existing components are used and thus separate components and associated with their production and assembly technical effort can be avoided.

In a further development of the invention it can be provided that the lift clamp comprises a fixed tab on the case extending away from the lower portion of the box in the space lying below the box and parallel to the plane of an opening adjacent to the lift terminal in the housing, and that on the lobes a parallel to the lower box section extending plate is formed, by means of which the flap is connected to the box. The section of the opening below the lower box section is covered thereby, thus avoiding erroneous insertion of ladders under the lower box section. The plate allows a relatively large-area contact with the box, thus ensuring a secure connection. Lifting clamps with fixed to the box lobes or shutters are for example from the EP 0 559 585 A and the US 5 580 285 A known. A disadvantage of the EP 0559 585 A proves that the tab shown there is integrally formed with the metallic box and thus does not provide an electrically insulating protection. The US 5 580 285 A whereas, in a particular embodiment, shows a removable shutter. However, this shutter is attached only with small hooks on the box, so that the resulting low composite surface ensures no secure connection.

In this context, it may further be provided that on the platelet a mounting plate running both normal to this and normal to the flap is integrally formed, which is firmly connected to a side wall of the box.

In a further embodiment of the invention may be provided in this context that a pin is formed on the mounting plate, which engages in an incorporated into the box side wall opening.

Thus, the box on particularly simple, with little technical effort associated type, namely by merely placing the box on the mounting plate, this will be fixed.

In this context, it can further be provided that in the mounting plate an opening is incorporated, in which engages a specified in the housing shear pin.

By this disposition of the shear bolt, in addition to its main function of providing resistance to displacement of the box, it can fulfill the auxiliary function of holding mounting plates, plates and lobes in the housing. When installing the components of the switch in the housing can thereby mounting plates, plates and

Rag can be used by machine in the lower shell.

• Fig.1 die Draufsicht auf einen mit erfindungsgemäßen Liftklemmen 1 ausgestatteten Leitungsschutzschalter bei abgenommener Oberschale;
• Fig.2 die lediglich mit einer Liftklemme 1 bestückte Unterschale des Leitungsschutzschalters gemäß Fig.1 im Schrägriß, wobei die zweite Liftklemme 1 außerhalb der Unterschale liegend dargestellt ist;
• Fig.3 eine Draufsicht auf eine lediglich mit der rechten Liftklemme 1 bestückte Unterschale des Leitungsschutzschalters gemäß Fig.1, wobei im Bereich der linken Liftklemme ein am Kasten 15 der Liftklemme 1 festlegbarer Lappen 24 vorgesehen ist;
• Fig.4 das in Fig.3 Gezeigte im Schrägriß;
• Fig.5 eine Draufsicht auf eine in einem Gehäuse eingebaute erfindungsgemäße Liftklemme 1, wobei der Widerstand, gegen welchen der Kasten 15 der Klemme 1 verschiebbar ist, durch eine Schrauben-Druckfeder 32 gebildet ist und
• Fig.6 das in Fig.5 Gezeigte, wobei zur Realisierung des Widerstandes anstelle der Schrauben-Druckfeder 32 ein an die Gehäuse-Innenwandung angeformter Abscherbolzen 33 vorgesehen ist.

The invention will be described in more detail with reference to the accompanying drawings, in which particularly preferred embodiments are shown. Showing:

• 1 is a plan view of a circuit breaker equipped with lift terminals 1 according to the invention with the top cover removed;
• FIG. 2 shows the lower shell of the circuit breaker according to FIG. 1 fitted with a lift clamp 1 in oblique view, the second lift clamp 1 being shown lying outside the lower shell; FIG.
• 3 shows a plan view of a lower shell of the circuit breaker according to FIG. 1, which is equipped only with the right lift clamp 1, wherein a tab 24 which can be fixed to the box 15 of the lift clamp 1 is provided in the region of the left lift clamp;
• 4 shows in Fig.3 Shown in the oblique view;
• 5 shows a plan view of a built-in housing according to the invention a lift clamp 1, wherein the resistor against which the box 15 of the terminal 1 is displaceable, is formed by a helical compression spring 32 and
• Fig.6 the shown in Figure 5, wherein for realizing the resistance instead of the helical compression spring 32 an integrally formed on the housing inner wall shear pin 33 is provided.

The circuit breaker shown in Figure 1 comprises two according to the invention, designed as so-called. "Lift terminals" screw terminals 1, by means of which lead wires and the comb-like terminal lugs of busbar systems can be connected to the circuit breaker.

The circuit breaker further comprises an overload trip element 2 and a short-circuit tripping device 3, next to a switching mechanism 4, which can move the movable contact 5 from a closed position in which the movable contact 5 is applied to the fixed contact 8 in the open position shown in Figure 1 ,

The current to be monitored flows through in this circuit breaker, starting from the right screw 1, first the overload trip element 2, passes through a movable Conductor 6 and the switching bridge 7 to the movable contact 5, then via the fixed contact 8 to the short-circuit tripping device 3 and finally to the second terminal. 1

The switching mechanism 4 can be actuated both by the short-circuit tripping device 3 and by the overload tripping element 2. The short-circuit tripping device 3 is formed in a conventional manner by a magnetic coil with a movable armature, which beats anchor at correspondingly high short-circuit currents on the switching bridge 7 of the switching mechanism 4.

The Überlastaüslöseelement 1 consists of a bimetallic strip, which is heated by the current to be monitored. The first end 21 of the bimetallic strip is fixed in the housing of the circuit breaker, the second end 22 is held freely movable. The bending thereof caused by the heating of the bimetal therefore leads to a movement of the second end 22 in the direction of the arrow 23. With sufficient heating, the free end 22 of the bimetallic strip in this movement comes into contact with the bracket 9 acting on the pawl support 36. takes this in the direction of motion and thereby triggers a response of the rear derailleur 4.

The switching bridge 7 is biased by a spring 10 in the direction of the open position of the movable contact 5. The explained minor deflections of the pawl support 36 by the armature of the short-circuit release device 3 and by the overload release element 2 via the bracket 9 are amplified by means of this spring 10 for complete pivoting of the switching bridge 7 in the open position of the movable contact 5.

To turn on the circuit breaker, i. for swiveling the contact carrier 7 back into the closed position of the movable contact 5, an externally accessible, manually operable lever 11 is provided.

The housing of the circuit breaker is in a conventional manner in two parts, consisting of the respectively apparent in the drawing figures lower shell 12 and not shown in the drawings, with respect to its structural design to the lower shell 12 mirror image of the upper shell executed.

The present invention relates to the lift clamps 1 and is not limited to the use of these lift clamps 1 in circuit breakers. In the drawings, only a line protection switch or the lower shell 12 of such was shown, because herein a particularly preferred application of the lift clamp according to the invention. 1 lies. However, it can nevertheless be used in electrical appliances of any type, that is to say, for example, in the case of a residual current circuit breaker, arrester isolating switch, staircase automaton, etc.

The lift clamp 1 according to the invention has, as previously known screw terminals of this type, a frame 14 which, viewed in the position shown in FIG. 1, is rectangular. It usually consists of a one-piece, three times 90 ° angled copper strip. This frame 14 is immovably held in the housing, which can be achieved for example by pinching between projections on the Unterschaleh inner wall. Second main component of a lift clamp 1 is the box 15, which is also frame-like (see also Fig.2). The box 15 is rotated 90 ° relative to the frame 14 and hung in it, i. the upper portion 150 of the box 15 lies between the upper portion 140 and the lower portion 141 of the frame 14. The box 15 is thus slidably guided in the frame 14.

The third main component of the lift clamp is the clamping screw 16. The upper portion 140 of the frame 14 has an opening 142 through which the clamping screw 16 is freely rotatably guided. In the upper portion 150 of the box 15, a thread 152 is incorporated, in which the clamping screw 16 engages. If the clamping screw 16 in the closing direction (ie clockwise when the clamping screw 16 as a right-hand screw) is rotated, the box 15 is lifted, i. moved toward upper frame section 140. This shift is due to the fact that the clamping screw 16 comes to rest with its foot-side end on the lower frame section 141 or with its head 160 on the upper frame section 140. Continued inward turning of the clamping screw 16 into the box thread 152 can thus not lead to displacements of the clamping screw 16 downwards, but only to a lifting of the box 15.

If the clamping screw 16 in the opening direction (ie counterclockwise when the clamping screw 16 as a right-hand screw) is rotated, the box 15 is lowered, i. moved toward the lower frame section 141.

Such a lift clamp 1 has two points at which electrical lines can be clamped. On the one hand, feed lines in the lying between the lower frame portion 141 and the lower box section 151 space 17 and Others are introduced into the lying between the upper frame portion 140 and the screw head 160 space 18 (see Fig.2). When tightening the clamping screw 16, both the lower portions 141 and 151 of the frame 14 and the box 15 against each other and the screw head 16 pressed against the upper frame portion 140 while the introduced into the spaces 17 and 18 lines clamped.

As a rule, 17 lead wires are inserted into the space lying between the lower frame section 141 and lower box section 151 and inserted into the space 18 located between the upper frame section 140 and screw head 16 a terminal lug of a busbar system. In order to keep these two rooms 17, 18 accessible for insertion of these electrical lines, openings 19 and 20 are provided in the housing at the level of these spaces.

In connection with the insertion of a lead wire in the lower space 17 there is, in particular when the clamp is not opened wide enough, i. the lower portion 150 of the box 15 is too close to the lower portion 141 of the frame 14 - the problem that this wire, although passed through the opening 19, but then mistakenly placed not in the space 17, but under the box 15. A proper pinching this wire is then no longer possible.

To prevent such mis-insertion of the lead wire, a tab 24 is fixed to the box 15, which is normal to the lower portion 151 of the box 15 and away from it, i. extends into the lying below the box 15 space. This flap 24 thus extends parallel to the plane of the opening 19 and is disposed immediately adjacent thereto.

Due to its connection with the box 15, the flap 24 is displaced together with the box 15 and thus covers the lying below the box 15 portion of the opening 19. A through this opening 19 inserted therethrough wire can only in between the lower frame portion 151th and lower box portion 141 lying space 17 are used, an above-described erroneous insertion of a wire under the box 15 is reliably avoided.

The tab 24 may be constructed arbitrarily: it could for example be made in one piece with the box 15, for example by being bent from the same conductive sheet metal strip as this box 15. But it can also be a separate from the box 15 and with the box 15 firmly connected-for example, welded or glued-component. It can be made of an insulating material, such as plastic be formed, which brings the additional advantage that the flap 24 can be safely touched even when its terminal is energized, which may for example be the case when the other terminal is already connected to a live conductor.

In the embodiment illustrated in FIGS. 1-4, a plate 25 running parallel to the lower box section 151 is formed on the tabs 24, via which tab the flap 24 is connected to the box 15. The plate 25 may be glued or welded to the lower box section 151, for example.

According to the embodiment of FIGS. 1-4, the connection between the plate 25 and the lower box section 151 is achieved by a mounting plate 26, which is formed on the plate 25 and extends normally both to this plate 25 and to the flap 24. This mounting plate 26 is fixedly connected to a side wall of the box 15, which could be realized again by gluing or welding of these two parts.

A preferred used and therefore also shown in Figures 1 to 4 variant for fixing the mounting plate 26 on the box 15 provides a pin 27, which is integrally formed on the mounting plate 26. In the box side wall, an opening 28 is incorporated, in which this pin 27 engages, whereby a positive fastening of the mounting plate 26 and thus of the tab 24 is achieved on the box 15.

As already explained, the lift clamp 1 in question has two places, namely the spaces 17 and 18, for clamping electrical lines, wherein normally in the lower space 17 lead wires and in the upper space 18, the terminal lug of a busbar system is used.

As a rule, it is so that only one type of line, so either a bus system terminal lug or a wire is connected to one and the same terminal.

When opening the clamp, the clamping screw 16 is not only rotated, but also pressed down with the screwdriver used for this purpose. This leads in lift clamps, which have only the previously discussed design features, that the screw head 16 is always pressed against the upper frame portion 141 and the rotation of the clamping screw 16 only in a downward displacement of the box 15, ie in an opening of the room 17 is implemented. Only when the box 15 all the way down is moved and comes in this position on the underlying housing part 29 to the plant, no further downward sliding of the box 15 can be done more. A still then exercised opening movement of the clamping screw 16 is converted into a post-upward displacement of the clamping screw 16, whereby the screw head 160 is lifted from the upper frame part 140 and the upper space 18 is opened.

When turning the clamping screw 16 in the closing direction of the first space 18 is closed, then the box 15 is raised until its lower portion 151 at the lower portion 141 of the frame 14 comes to rest and only then after further continued rotation of the clamping screw 16 in the closing direction of the Screw head 160 clamped pressed against the upper frame portion 140.

By this operation is conditional that then when a lift terminal 1 only a bus system terminal lug is to be connected, first the clamping screw 16 must be opened in its entirety and after insertion of the terminal lug in the room 18 must be fully closed again.

• So kann beispielsweise der Kasten 15 am Rahmen 14, oder an Teilen des Gehäuses reibend anliegen. Die damit gegebene Haftreibung zwischen dem Kasten 15 und dem Rahmen 14 oder den Gehäuseteilen verhindert zunächst die oben erörterte Verschiebung des Kastens 15 gegen über dem Rahmen 14, womit die Klemmschraube 16 bei Drehen in Öffnungsrichtung aus Kasten 15 und Rahmen 14 heraus- bzw. bei Drehen in Schließrichtung in Kasten 15 und
• Rahmen 14 hinein wandert. Der (Reibungs-)Widerstand wird so dimensioniert, daß er überwunden werden kann, beispielsweise durch Ausüben eines Druckes auf den Schraubenkopf 160. Dies erlaubt es, daß bei Drehung der Klemmschraube 16 -sofern erwünscht- sofort der untere Raum 17 geöffnet werden kann.

According to the invention, to remedy this, a time-consuming assembly process-related circumstance provided that the box 15 of the lift clamp 1 in the frame 14 is not free, but held against a resistance displaceable. This resistance can be realized in different ways:

• Thus, for example, the box 15 rub against the frame 14, or parts of the housing. The resulting static friction between the box 15 and the frame 14 or the housing parts initially prevents the above-discussed displacement of the box 15 relative to the frame 14, whereby the clamping screw 16 when turning in the opening direction of box 15 and frame 14 out or when turning in the closing direction in box 15 and
• Frame 14 moves in. The (friction) resistance is dimensioned so that it can be overcome, for example by exerting a pressure on the screw head 160. This allows that upon rotation of the clamping screw 16 - if desired - immediately the lower space 17 can be opened.

In the exemplary embodiment of the housing shown in FIG. 1, a rib 30, into which a bore 31 is embedded, is located above the screw head 160. This bore 31, which serves for the passage of the screw driver necessary for rotating the clamping screw 16, has a smaller diameter than the head 160 of the clamping screw 16.

When moving upwards the clamping screw 16, which then takes place during rotation in the opening direction, if not at the same time a pressure on the clamping screw 16 is exerted, the screw head 160 comes to rest on the rib 30. If the clamping screw 16 now continues to be rotated in the opening direction, the box 15 is pressed downwards, since the clamping screw 16 can no longer move upwards. The resistance is overcome and the box 15 is moved down.

The resistance can be realized, as shown in FIG. 5, by means of a spring 32, which pretensions the box 15 in the direction of the frame 14. This spring 32 can be formed by a leaf spring or -so as shown in Figure 5 explicitly represented by a helical compression spring which is below the box 15 and at one end to the housing part 29 and the other -unter mediation of the plate 25, if one Such is provided at the lower portion 151 of the box 15 is supported.

There may be several variants of the realization of the resistor at the same time, for example, the box 15 may be mounted on both the frame 14 and the housing rubbing or it may be in addition to the frictional mounting of the box 15 on the frame 14, a spring 32 may be present.

As can be seen from these discussions of the function of the resistor, such or necessary for its realization components can be independent of a flap 24, i. even if such a tab 24 is missing, be provided. If there is a tab 24, the resistance can be realized by friction bearing this tab 24 in the housing 12.

The possibilities of realizing the resistance discussed so far have in common that they constantly exercise this resistance, i. that this resistance is not significantly changed by displacements of the box 15.

In a preferred embodiment of the invention, a shear pin 33 is provided which is secured in the housing. The shear pin 33 is positively connected to the box 15 when it is in the position shown in Figure 1 and Figure 6. This can be achieved, for example, by engaging the shear pin 33 in an aperture machined into the box sidewall, or by placing the shear pin 33 just below the lower box portion 151, as shown in FIG.

Upon rotation of the clamping screw 16 in the opening direction of the shear bolt 33 initially any displacement of the box 15 is prevented, the rotational movement is implemented exclusively in an up-wander the clamping screw 16. Will one sufficiently large, extending in its longitudinal direction compressive force exerted on the clamping screw 16 (for example, by a blow to the clamping screw 16 or further rotation of the clamping screw 16 when the head 160 is already applied to the rib 30), the shear pin 33 is sheared off and the box 15th can now be moved freely.

In this variant of the realization of the resistance of this is only temporarily, namely exercised only before shearing the shear bolt 33.

With intact shear bolt 33 only the space 18 is opened or closed, so that the terminal lug of a busbar system connected with little effort can be connected to the lift clamp 1.

• Bei dieser Ausführungsform ist -wie oben schon näher erläutert- ein Lappen 24 vorgesehen, an welchen ein Plättchen 25 angeformt ist, mit welchem das Montageplättchen 26 einstückig ausgebildet ist. Dieses Montageplättchen 26 ist in einer, ins Gehäuse eingelassenen rechteckigen Führungsnut 34 in zur Verschiebungsrichtung des Kastens 15 paralleler Richtung verschiebbar gelagert. Zur Verbindung des Montageplättchens 26 mit dem Kasten 15 ist ein an das Montageplättchen 26 angeformter. Stift 27 vorgesehen, der in eine in der Kastenseitenwand eingearbeitete Durchbrechung 28 eingreift.
• Der Abscherbolzen 33 ist dabei an den Boden dieser Führungsnut 34 angeformt. Das Montageplättchen 26 weist eine Durchbrechung 35 auf, in welche der Abscherbolzen 33 eingreift (vgl. Fig.2,3). Der Abscherbolzen 33 ist dabei indirekt, nämlich unter Vermittlung des Montageplättchens 26 und des Stiftes 27 mit dem Kasten 15 verbunden.
• Damit hier eine auf die Klemmschraube 16 ausgeübte Druckkraft tatsächlich nur eine Abscherung des Abscherbolzens 33, nicht aber des Stiftes 27 bewirkt, ist die Abscherfestigkeit dieses Stiftes 27 entsprechend höher als jene des Abscherbolzens 33 zu dimensionieren.
• Der Abscherbolzen 33 hat bei dieser Ausführung die Nebenfunktion, daß er das Montageplättchen 26 bzw. mit diesem den Lappen 24 während der Montage des Schalters, d.h. beim Einsetzen der einzelnen Bauteile in die Gehäuse-Unterschale, an der korrekten Position hält. Das Montageplättchen 26 mit angeformten Plättchen 25 und Lappen 24 kann damit maschinell in die Unterschale eingesetzt werden, Rahmen 14 und Kasten 15 der Liftklemmen 1 können dann ohne Schwierigkeit auf das Montageplättchen 26 aufgesetzt werden.

In the preferred embodiment shown in more detail in the drawings Fig.1-4 also such a shear pin 33 is provided, which, however, is only indirectly connected to the box 15:

• In this embodiment, as already explained in more detail above, a tab 24 is provided, on which a small plate 25 is formed, with which the mounting plate 26 is integrally formed. This mounting plate 26 is slidably mounted in a, recessed into the housing rectangular guide groove 34 in the direction of displacement of the box 15 parallel direction. To connect the mounting plate 26 with the box 15 is integrally formed on the mounting plate 26. Pin 27 is provided, which engages in an incorporated in the box side wall opening 28.
• The shear pin 33 is integrally formed on the bottom of this guide groove 34. The mounting plate 26 has an opening 35 in which the shear pin 33 engages (see Fig. 2,3). The shear pin 33 is indirectly, namely connected by the intermediary of the mounting plate 26 and the pin 27 with the box 15.
• In order for a compressive force exerted on the clamping screw 16 to actually effect only a shearing of the shear pin 33, but not of the pin 27, the shearing strength of this pin 27 is correspondingly greater than that of the shear pin 33.
• The shear pin 33 has in this embodiment the secondary function that he holds the mounting plate 26 and with this the flap 24 during assembly of the switch, ie when inserting the individual components in the housing lower shell, at the correct position. The mounting plate 26 with molded plates 25 and tabs 24 can thus be used by machine in the lower shell, frame 14 and box 15 of the lift clamps 1 can then be placed without difficulty on the mounting plate 26.

Claims (5)

1. A lifting clamp (1) for installation in a housing of an electric device such as a circuit-breaker, comprising a rectangular frame (14) and a rectangular box (15) whose upper section (150) is disposed between the upper section (140) and the lower section (141) of the frame (14), by means of which the box (15) is held displaceably in the frame (14), further comprising a clamping screw (16) which is guided in a freely rotatable fashion through a breakthrough (142) incorporated in the upper frame section (140) and engages in a thread (152) integrated in the upper section (150) of the box (15), with the box (15) being held displaceably against a resistance in the frame (14), characterized in that the resistance is formed by a shearing pin (33) which is fastened to the housing, is preferably arranged integrally with the housing and is connected with the box (15) in a positive manner.
2. A lifting clamp (1) according to claim 1, characterized in that the lifting clamp (1) comprises a lug (24) fixed to the box (15), which lug extends away from the lower section (151) of the box (15) to the space situated below the box (15) and parallel to the plane of an opening (19) in the housing situated adjacent to the lifting clamp (1), and that a small plate (25) is shaped on the lugs (24) which extends parallel to the lower box section (151) and by means of which the lug (24) is connected to the box (15).
3. A lifting clamp (1) according to claim 1, characterized in that a mounting plate (26) is shaped on the small plate (25), which mounting plate extends in a normal manner to the same as well as normal to the lug (24) and which is rigidly connected to a side wall of the box (15).
4. A lifting clamp (1) according to claim 3, characterized in that a pin (27) is shaped on the mounting plate (26) which engages in a breakthrough (28) incorporated in the side wall of the box.
5. A lifting clamp (1) according to claim 3 or 4, characterized in that a breakthrough (35) is incorporated in the mounting plate (26), into which the shearing pin (33) engages which is fixed in the housing.

Images