EP4287411A1 - Underplug protection part - Google Patents

Abstract

The invention relates to an under-plug protection part (1) for sliding onto a clamping frame (2) of a screw terminal (3), - the under-plug protection part (1) has the shape of a closed frame, which has two opposing longitudinal elements (L1, L2) and a first and a second transverse element (Q1, Q2), which lie opposite one another and each connect the longitudinal elements to one another, - the first transverse element (Q1) having a through opening (A) for passing through a screw shaft and - wherein on the second transverse element (Q2) a A cover apron (S) serving as under-plug protection is formed.

Description

The present invention relates to an underplug protection part, a screw terminal and an installation device.

Installation devices, d. H. Electrical components used in distributions, which are often mounted on a top-hat rail, are usually connected to electrical lines using spring terminals or screw terminals.

When it comes to screw terminals, a distinction is made between single-chamber and double-chamber terminals, depending on whether the screw terminal has one or two terminal chambers. A stripped end of an electrical cable is inserted into a terminal chamber, also referred to as a conductor receiving space or simply as a chamber, and clamped therein by tightening a screw, which is also referred to as a clamping screw.

Single-chamber terminals, which have a single terminal chamber, are differentiated between pressure piece terminals and elevator terminals. With pressure piece clamps, when the screw rotates, the screw with a pressure piece attached to the screw tip moves along the screw axis relative to a fixed clamping frame; Any existing terminal connection is fixed. Pressure piece clamps are e.g. Am DE8134378U (Siemens AG) February 25, 1982 and EP0735614A2 (Weidmüller Interface GmbH & Co.) October 2, 1996 disclosed. In elevator clamps, when the screw rotates, a clamping frame moves along the axis of the screw, while the screw itself does not experience any movement in the axial direction. Elevator clamps are e.g. Am DE1802558A1 (Woertz, Oskar, Basel, Switzerland) July 31, 1968 disclosed.

Double chamber clamps have both a movable pressure piece and a movable clamp frame, both can be moved relative to a stationary terminal connection by turning the screw. This makes it possible to have an upper chamber between the pressure piece and the terminal connection and a lower chamber between the terminal connection and the underside of the terminal frame. Double chamber terminals are e.g. Am DE1935560U (Georg Schlegel, Electrotechnical Factory) March 31, 1966 and DE3314919A1 (Murr Elektronik GmbH) October 25, 1984 disclosed.

Double-chamber terminals offer more convenience than single-chamber terminals because two cables with different diameters or one cable and a busbar can be connected in a double-chamber terminal. However, double chamber clamps, like elevator clamps, have the following disadvantage: When the screw clamp is closed, the clamp frame moves upwards, i.e. H. towards the screw head. This makes a cavity accessible under the clamping frame. So there is a risk that an installer will not insert one end of the cable into the lower terminal chamber, but into the cavity underneath. This is facilitated by the fact that the installation situation is often poorly lit and cannot be seen directly. The installer may therefore mistakenly believe that he has inserted the end of the cable into the lower terminal chamber, when in fact he has inserted it into the cavity below, a so-called under-plugging, mis-plugging or behind-plugging. When tightening the screw, the incorrectly inserted cable end is therefore not clamped; Nevertheless, it can touch electrically active parts, which even makes it difficult to find the fault using a continuity tester. If a load current is applied, high heating and thus a destructive effect can occur due to the high contact resistance due to a lack of contact pressure.

DE 100 18 352 C1 (Siemens AG) September 27, 2001 describes a double-chamber clamp in which an apron is mounted on the bottom of the clamp frame, which prevents it from being inserted underneath. There are cuts on the side of the apron. Through this Two tabs are formed which are bent below the base of the clamping frame. In this way the apron is firmly held on the clamping frame.

DE 10 2016 122 852 A1 (ABB Schweiz AG) May 30, 2018 discloses an elevator terminal with a terminal cover part that has an apron serving as an underplug protection. Due to the trough-shaped cross section with two short legs at the ends and a connecting web connecting the two short legs, it is possible to slide the terminal cover part with the apron onto the terminal frame after it has already been mounted in a housing half-shell.

The object of the present invention is an improved underplug protection.

This object is achieved according to the invention by an underplug protection part with the features specified in claim 1. The under-plug protection part is suitable for sliding onto a clamping frame of a screw terminal. The under-plug protection part has the shape of a closed frame which has two longitudinal elements lying opposite one another and a first and a second transverse element, which lie opposite one another and each connect the longitudinal elements to one another. The first transverse element has a feed-through opening for passing a screw shaft through. And a cover apron that serves as under-plug protection is molded onto the second cross element.

The invention is based on the finding that an underplug protection part in the form of a closed frame deforms significantly less, e.g. B. when an installer touches the cover skirt with one end of the conductor, as an under-plug protection part which does not have the shape of a closed frame; Therefore, an under-plug protection part in the form of a closed frame can be better guided in the housing of an installation device than a under-plug protection part which does not have the shape of a closed frame. Thus is It is also almost impossible for the under-plug protection part to get caught or wedged.

Compared to an under-plug protection part, which does not have the shape of a closed frame, the under-plug protection part according to the invention with its symmetrical shape has the advantage that forces acting on the frame are transmitted evenly through the frame. The under-plug protection part is therefore better guided and can be better attached to a clamping frame in which a screw, also known as a clamping screw, is guided in a threaded hole. The tight fit, for example when an installer hits the cover skirt with the end of a conductor, is better with a symmetrical frame than with an asymmetrical frame.

In addition, the closed frame shape allows the underplug protection part to be easily pushed onto a clamping frame of a screw terminal. Because the cover apron is molded onto the frame of the under-plug protection part, there is no need to have a holding contour on the clamping frame that is specifically used to fix the cover apron, e.g. B. a nose or a hole can be provided. The underplug protection part according to the invention can therefore be used on several different clamping frames.

Advantageous refinements and further developments of the invention are specified in the dependent claims.

According to a preferred embodiment of the invention, the first transverse element forms a ring which encloses the feed-through opening. In this case, the under-plug protection part must be pushed over a clamping frame before the pressure piece is attached to the clamping frame together with the clamping screw. The advantage of this configuration is that the under-plug protection part is fixed to the clamping frame by a clamping screw guided in the clamping frame; the tight fit is therefore very stable.

According to a preferred embodiment of the invention, the first transverse element forms a semicircular arch which encloses the feed-through opening on three sides. The under-plug protection part can then be pushed onto the clamping frame from the side before mounting the pressure piece on the clamping frame. The advantage of this configuration is that an under-plug protection part with a semicircular arc can be assembled better than an under-plug protection part with a closed ring. A further advantage of this configuration is that only an open-close injection molding tool is required for the production of the underplug protection part, whereas a side slide in the injection molding tool is required for the production of a variant of the underplug protection part, in which the first cross element has a ring surrounding the feed-through opening becomes.

According to a preferred embodiment of the invention, the semicircular arch has a separating joint in the area of an arch apex of the arch, preferably separating the arch into two arch segments of equal length. The advantage of this configuration is that the under-plug protection part can be mounted on a clamping frame on which a pressure piece is already mounted: through the parting joint, the ends of the arch segments separated by the parting joint can be bent apart and guided around the pressure piece.

According to a preferred embodiment of the invention, the cover apron is designed as a plate which lies parallel to the plane spanned by the longitudinal and transverse elements. The advantage here is that the parallel position effectively prevents a terminal chamber from being plugged underneath a screw terminal.

According to a preferred embodiment of the invention, at least one spring element is formed on the second transverse element, which is designed so that an elastic deformation of the spring element, which occurs when the under-plug protection part moves in a direction parallel to the longitudinal elements in the direction from the first transverse element to the second transverse element, leading to a restoring force in an opposite direction. The advantage here is that the spring element exerts an upward force on the clamping frame and thus creates a forced position of the clamping frame: The spring elements under the clamping frame ensure that the upper clamping chamber, also referred to as the upper conductor insertion opening, is completely open and the lower clamping chamber, also referred to as the lower conductor insertion opening, is kept closed except for a small gap, preferably approx. 1.5 mm, sufficient for contact tabs of a busbar. As a result, the lower clamping chamber of a double-chamber clamp is almost closed and the upper clamping chamber is completely open, just as the installer expects at the beginning of the connection as the delivery state of the installation device.

The delivery status of the screw terminal mounted in the installation device is as follows: The upper chamber of the screw terminal is completely open to enable conductor insertion of even the thickest conductor end. The lower chamber of the screw clamp is almost closed: the spring elements, which are preferably designed as little legs, push the clamp frame upwards due to their spring force; The clamping frame remains in a position where the spring legs are completely relaxed and the lower conductor insertion opening has an opening height of 1.5 mm: this opening of 1.5 mm is sufficient for inserting the contact tabs of a busbar. To connect thicker conductors, the installer can use a screwdriver or similar tool to press the clamping frame down against the force of the spring legs while turning the clamping screw.

A further embodiment of the invention is an underplug protection part, manufactured by plastic injection molding. For example, PA66 can be used without fiberglass reinforcement, which gives the underpinning protection part relatively high flexibility.

A further embodiment of the invention is a screw clamp in the manner of an elevator clamp. The screw terminal has a clamping frame with a head bar and a bottom bar, which lie opposite one another. The screw terminal has a screw which is screwably mounted in a threaded hole in the head web; this screw is also known as a clamping screw. The screw terminal also has an underplug protection part, as described above. The under-plug protection part encloses the clamping frame, the through opening of the under-plug protection part is arranged in alignment with the threaded hole and the cover skirt of the under-plug protection part projects beyond the base web in the direction away from the head web.

According to a preferred embodiment of the screw terminal, the head web carries on its outside facing away from the base web a threaded flange which encloses the threaded hole, the first transverse element of the under-plug protection part having an inner corner along the feed-through opening on its side facing the second transverse element, against which the threaded flange rests.

According to a preferred embodiment of the screw terminal, the screw terminal is a double-chamber terminal.

According to a preferred embodiment of the screw terminal, the under-plug protection part sits on the clamping frame in such a way that the two longitudinal elements of the under-plug protection part divide side parts of the clamping frame, which each extend between the head web and the bottom web, into contact surfaces of approximately the same size. The side parts of the clamping frame connect the head bar and the bottom bar of the clamping frame to each other at their ends, thus forming the clamping frame just like the head bar and the bottom bar. When looking frontally at the side parts of the clamping frame, the two longitudinal elements of the base protection part run approximately along a line which bisects the side parts of the clamping frame from the head bar and the bottom bar. Decisive is not that the longitudinal elements of the under-plug protection part run exactly in the vertical center line of the side parts of the clamping frame, but that the side parts of the clamping frame each have a contact surface on their outer edges. It is advantageous that a screw torque, which is caused by turning a screw to move the clamping frame and the pressure piece, can be transferred to the housing of the installation device via the contact surfaces of the clamping frame; otherwise, ie if this screw torque were to be transferred to the housing of the installation device via the longitudinal elements of the under-plug protection part, there is a risk that the resulting increased friction between the under-plug protection part and the housing has a detrimental effect on movement of the screw terminal. Due to the symmetrical positioning of the under-plug protection part on the clamping frame, contact surfaces of approximately the same size are formed on the outside of the side parts of the clamping frame.

A further embodiment of the invention is an installation device with a screw terminal, as described above. The installation device can be divided into two housing halves. Before plugging the two housing halves together, the screw terminal can be inserted into one of the two housing halves. The installation device can be any device that has screw terminals for holding and fixing conductor ends of electrical cables. In particular, the installation device can be an installation switching device such as an Air Circuit Breaker, Arc Fault Detection Device, Arc Fault Circuit Interrupter, Circuit Breaker, Electronically Controlled Protection Device, Miniature Circuit Breaker, Molded Case Circuit Breaker, Residual current operated Circuit-Breaker with Overcurrent protection, Residual Current Device, Residual Current Circuit Breaker or Surge Protection Device.

Fig. 1

eine Schrägansicht eines Untersteckschutzteils;

Fig. 2

eine Schrägansicht des in Fig. 1 dargestellten Untersteckschutzteils, das auf einen Klemmrahmen einer Schraubklemme aufgeschoben ist;

Fig. 3

zwei unterschiedliche Ansichten einer alternativen Variante des Untersteckschutzteils;

Fig. 4

zwei unterschiedliche Ansichten einer weiteren alternativen Variante des Untersteckschutzteils;

Fig. 5

eine Schraubklemme mit dem in Fig. 3 gezeigten Untersteckschutzteil;

Fig. 6

eine Seitenansicht der in Fig. 5 gezeigten Schraubklemme, eingesetzt in eine Gehäuse-Halbschale eines Installationsgerätes;

Fig. 7

eine Schnittansicht der in Fig. 5 gezeigten Schraubklemme, eingesetzt in ein Installationsgerät;

Fig. 8

eine Schrägansicht der in Fig. 5 gezeigten Schraubklemme im offenen Zustand, eingesetzt in ein Installationsgerät;

Fig. 9

eine Schrägansicht der in Fig. 5 gezeigten Schraubklemme im geschlossenen Zustand, eingesetzt in ein Installationsgerät;

Fig. 10

eine Seitenansicht der in Fig. 5 gezeigten Schraubklemme, eingesetzt in eine Gehäuse-Halbschale eines Installationsgerätes mit einer Schieberhandbetätigung;

Fig. 11

eine Schrägansicht der in Fig. 5 gezeigten Schraubklemme im offenen Zustand, eingesetzt in ein Installationsgerät mit einer Schieberhandbetätigung;

Fig. 12

eine Schrägansicht der in Fig. 5 gezeigten Schraubklemme im geschlossenen Zustand, eingesetzt in ein Installationsgerät mit einer Schieberhandbetätigung; und

Fig. 13

eine Seitenansicht eines Untersteckschutzteils.

The invention is explained below using several exemplary embodiments with the aid of the accompanying drawing. It shows each schematically and not to scale

Fig. 1

an oblique view of an underplug protection part;

Fig. 2

an oblique view of the in Fig. 1 shown under-plug protection part, which is pushed onto a clamping frame of a screw terminal;

Fig. 3

two different views of an alternative variant of the under-plug protection part;

Fig. 4

two different views of a further alternative variant of the under-plug protection part;

Fig. 5

a screw terminal with the in Fig. 3 shown underplug protection part;

Fig. 6

a side view of the in Fig. 5 screw terminal shown, inserted into a housing half-shell of an installation device;

Fig. 7

a sectional view of the in Fig. 5 screw terminal shown, inserted into an installation device;

Fig. 8

an oblique view of the in Fig. 5 screw terminal shown in the open state, inserted into an installation device;

Fig. 9

an oblique view of the in Fig. 5 screw terminal shown in the closed state, inserted into an installation device;

Fig. 10

a side view of the in Fig. 5 screw terminal shown, inserted into a housing half-shell of an installation device with a slide manual actuation;

Fig. 11

an oblique view of the in Fig. 5 screw terminal shown in the open state, inserted into an installation device with a slide manual operation;

Fig. 12

an oblique view of the in Fig. 5 screw terminal shown in the closed state, inserted into an installation device with a slide manual operation; and

Fig. 13

a side view of an underplug protection part.

Fig. 1 shows an underplug protection part 1, which is suitable for sliding onto a clamping frame of a screw terminal. To simplify the description, in Fig. 1 a right-handed Cartesian coordinate network is given. To simplify the description, the terms "top" and "bottom" are used in relation to the under-plug protection part 1, as is the under-plug protection part 1 in Fig. 1 is oriented; However, these directional or location information should not be restrictive for the position of the under-plug protection part 1 in an actual application.

The under-plug protection part 1 has the shape of a closed frame lying in the x-y plane, which has two longitudinal elements L1, L2 opposite one another at a clear distance l in the y-direction and a first and a second transverse element Q1, Q2 in the x-direction. According to the orientation of the underplug protection part 1, the first cross element Q1 can also be referred to as an upper cross element and the second cross element Q2 can also be referred to as a lower cross element. The two transverse elements Q1, Q2 lie opposite each other at a clear distance q and connect the longitudinal elements L1, L2 to each other at their ends.

The two longitudinal elements L1, L2 have a rectangular cross section; They have two wider side surfaces, whose surface normals are parallel to the x-axis, and two narrower side surfaces whose surface normals are parallel to the z-axis.

The first transverse element Q1 forms a ring 10 which encloses a circular feed-through opening A for passing through a screw shaft. The second transverse element Q2 has a rectangular cross section, similar to the longitudinal elements L1, L2. A web 14 is formed on a narrow side surface of the second transverse element Q2, which carries a cover apron S in the form of a square plate that serves as an underpinning protection. The plane of the web 14 lies parallel to the xz plane, while the plane of the cover skirt S lies parallel to the xy plane. The cover skirt S projects beyond the second transverse element Q2 in a direction facing away from the first transverse element Q1.

On a downward-pointing edge of the cover apron S, ie on the edge pointing against the y-direction, a nose 15 is formed in the middle, which protrudes from the edge against the y-direction and contributes to its function Fig. 6 is described. The nose can have a rectangular, preferably square, outline when viewed in the z direction.

A spring element F in the form of a foot is formed on each of the two frame corners of the under-plug protection part 1, which are formed by the transitions from the longitudinal elements L1, L2 to the second transverse element Q2. The two spring elements F each have the shape of a 90° arc, with the two arcs pointing towards each other. While the plane of the cover skirt S is offset in the z-direction to the frame plane of the under-plug protection part 1, the spring elements F are offset against the z-direction to the frame plane of the under-plug protection part 1. If the under-plug protection part 1 is moved counter to the y-direction against a fixed surface, the spring elements F are bent, which leads to a spring force in the y-direction.

Fig. 2 shows that in Fig. 1 Under-plug protection part 1 shown is pushed onto a clamping frame 2 of a screw terminal. To simplify the description, in Fig. 2 a right-handed Cartesian coordinate network is given. The clear distances l, q of the longitudinal and transverse elements L1, L2 and Q1, Q2 are dimensioned such that the under-plug protection part 1 only has enough play against the clamping frame 2 so that the under-plug protection part 1 can be pushed manually onto the clamping frame 2 is, but on the other hand, an unwanted and disruptive movement of the under-plug protection part 1 pushed onto the clamping frame 2 is prevented relative to the clamping frame 2.

The clamping frame 2 has the shape of a closed frame lying in the xy plane, which has two opposite side parts 21, 22 in the y direction and a head web 23 and a bottom web 24, each in the x direction. The head web 23 and the bottom web 24 connect the side parts 21, 22 to each other at their ends.

The frame elements forming the clamping frame, ie the two side parts 21, 22, the head web 23 and the bottom web 24, each have a rectangular cross section; These frame elements each have two wider side surfaces, whose surface normals lie parallel to the xy plane, and two narrower side surfaces, whose surface normals lie parallel to the z-axis. In the middle of the head web 23 there is a circular threaded hole 26 for receiving a screw, the axis of which runs in the y-direction. In addition, the head web 23 carries a threaded flange 25 on its outside facing away from the bottom web 24, which encloses the threaded bore 26. The surface of the bottom web 24 facing the head web 23 is designed as a profiled surface 27 in the form of ribs; An end of a line, which usually has a conductor (solid wire or stranded wire) made of a relatively soft metal such as copper or aluminum, can be inserted into the profile 27 of the floor web 24, which is preferably made of a relatively hard metal such as iron or steel Contact pressure of a screw mounted screwably in the threaded hole 26 can be pressed in so that the conductor can be clamped there particularly securely (frictional connection + positive connection).

The under-plug protection part 1 encloses the clamping frame 2 on its entire outer circumference, the passage opening A of the under-plug protection part 1 being arranged in alignment with the threaded hole 26 of the clamping frame 2 and the cover skirt S of the under-plug protection part 1 protruding beyond the base web 24 in a direction facing away from the head web 23. The first transverse element Q1 of the under-plug protection part 1 has an inner corner on its side facing the second transverse element Q2 along the feed-through opening A, against which the threaded flange 25 of the clamping frame 2 rests.

Fig. 3 shows two different views of an alternative variant of the under-plug protection part 1. All elements of the in Fig. 3 shown underplug protection part 1 except the first cross element Q1 are designed the same as that in the Fig. 1 and 2 shown under-plug protection part 1. Different than in Fig. 1 and 2 forms at the in Fig. 3 shown under-plug protection part 1, the first cross element Q1 has a semicircular arch 11, which encloses the feed-through opening A on three sides. The opening of the semicircular arch 11 is arranged on the side of the under-plug protection part 1 opposite the cover apron S.

Fig. 4 shows two different views of another alternative variant of the under-plug protection part 1. All elements of the in Fig. 4 shown underplug protection part 1 except the first cross element Q1 are designed the same as in the Fig. 1 to 3 shown under-plug protection parts 1. As in Fig. 3 points to the in Fig. 4 shown under-plug protection part 1, the first cross element Q1 has a semicircular arc 11, which encloses the feed-through opening A on three sides. However, the semicircular arch 11 has one in the area of an arch apex of the arch 11 Parting line 12. As a result, the arch halves 11a, 11b of the arch 11, which are separated by the parting line 12, can be bent open so that they can be guided over a pressure piece mounted on a screw, see Fig. 5 . This flexibility is achieved by the under-plug protection part 1 made of a plastic, e.g. B. PA66 without fiberglass reinforcement.

In Fig. 3 and 4 The spring elements F and the inner corner 13, which are designed in the same way in all three drawn variants of the under-plug protection part 1, can be seen.

Fig. 5 shows a screw clamp 3 of the elevator clamp type, which has a clamping frame 2, an under-plug protection part 1 pushed onto the clamping frame 2, a screw 30 screwably mounted in the clamping frame, a pressure piece 40 mounted on a screw head of the screw 30 and a gripping protection 42 attached to the pressure piece 40 having. The reach-around protection prevents the fitter from reaching around the installation device, e.g. B. when mounting on the top-hat rail or when moving, the fitter's hand comes into contact with conductive components. The screw terminal 3 is suitable for use in an installation device; there is in Fig. 5 a terminal connection K of the installation device is also shown, which protrudes into the interior of the clamping frame 2. To simplify the description, the terms "top" and "bottom" are used with respect to the screw terminal 3, as is the screw terminal 3 in Fig. 5 is oriented; However, these directional or location information should not be restrictive for the position of the screw terminal in an actual application.

The screw 30 has a screw head with a cross slot for attaching a corresponding screwdriver and a threaded body adjoining the screw head, the screw being inserted from above into a threaded hole in the clamping frame 2, as in Fig. 2 shown is screwed in. By turning the screw 3 further, the pressure piece becomes 40 moves from above and the bottom web 24 from below against the terminal connection K.

A head plate of the pressure piece 40 lies around the screw head of the screw 30, so that an axial movement of the screw generates a corresponding movement of the pressure piece.

The pressure piece 40 can be made of tin-plated steel, the clamping frame 2 can be made of copper-plated steel, the grip protection 42 can be made of plastic, the under-plug protection part 1 can be made of plastic and the screw 30 can be made of steel. These material specifications are only exemplary, but not restrictive. The parts can also be made of other suitable materials.

Fig. 6 is a side view of the in Fig. 5 screw terminal 3 shown, inserted into a second housing half-shell 62 of a housing 60 of an installation device 4. In Fig. 6 the screw shaft 32 of the screw 30, which is provided with a screw thread, can be seen, as well as the pressure piece 40, which has a ring element placed around the screw head 31 of the screw 30, so that an axial movement of the screw head 31 results in a movement of the pressure piece 40 relative to the fixed terminal connection K im Interior of the clamping frame 2 leads. The downwardly projecting nose 15 formed on the cover apron S always remains behind the beveled frame 68 in every position of the cover apron S, see Fig. 12 , and thus provides guidance for the cover apron S.

Fig. 7 is a sectional view of the in Fig. 5 screw terminal 3 shown, inserted into the housing 60 of the installation device 4, which is formed from a first housing half-shell 61 and a second housing half-shell 62. In the Fig. 6 and 7 a state of the screw terminal 3 is shown in which an upper conductor insertion opening 66, which lies between the pressure piece 40 and the terminal connection K, is opened and a lower conductor insertion opening 67, which lies between the terminal connection K and the bottom web 24 of the clamping frame 2, closed is. A cavity located below the base web 24 of the clamping frame 2 is covered by the cover skirt S in such a way that a conductor end is prevented from being inserted underneath.

The downward-pointing nose 15, which is formed centrally on the downward-pointing edge of the cover apron S, ensures that the cover apron S does not thread out of the lower conductor insertion opening 67 in any part tolerance situation. To achieve this effect, the entire lower edge of the cover skirt S could alternatively be extended to the lower edge of the nose 15, which would require more material than if only the centrally arranged nose 15 was formed. But a material-intensive extension of the entire cover apron S is not necessary, since the cover apron S does not have to hermetically seal the lower conductor insertion opening 67, but rather only has to prevent a conductor, which always has a certain minimum thickness, from being inserted into the lower conductor insertion opening 67. The projection of the nose 15 downwards over the lower edge of the cover skirt S is therefore chosen to be approximately as large as the minimum diameter of a conductor end. By designing the guide element and unthreading protection as a nose 15, material is saved.

Fig. 8 and 9 are oblique views of the in Fig. 5 screw terminal 3 shown, inserted into a housing 60 of an installation device 4; thereby showing Fig. 8 the screw terminal 3 in the open state and Fig. 9 the screw terminal 3 in the closed state. Both figures show an access opening 65 arranged in the housing 60, through which the screw head of the screw 30 of the screw terminal 3 is accessible, so that it can be used, for example. B. can be applied with a screwdriver. On a narrow side 64 of the housing 60 composed of two housing half-shells 61, 62, recognizable by a joining line 63, the conductor insertion openings 66, 67 of the screw terminal 3 are accessible through corresponding housing recesses in the housing 60. While in the in Fig. 8 shown open State of the screw terminal 3, the upper conductor insertion opening 66 is completely open and the lower conductor insertion opening 67 is open by approximately 1.5 mm, are in the in Fig. 9 shown closed state of the screw terminal 3, both conductor insertion openings 66, 67 are completely closed. In both states, however, the screw terminal 3 is prevented from being plugged underneath by the cover skirt S.

Fig. 10 is a side view of the in Fig. 5 screw terminal 3 shown, inserted into a first housing half-shell 61 of a housing 60 of an installation device 4, which has a slide manual actuation 50; The slide manual actuation 50 enables the installation device 4 to be released from a top-hat rail or from a busbar assembly without tools.

Fig. 11 and 12 are oblique views of the in Fig. 5 screw terminal 3 shown, inserted into a housing 60 of an installation device 4, which has a slide manual actuation 50. Fig. 11 shows the screw terminal 3 in the open state and Fig. 12 the screw terminal 3 in the closed state. Both figures show an access opening 65 arranged in the housing 60, through which the screw head of the screw 30 of the screw terminal 3 is accessible, so that it can be used, for example. B. can be applied with a screwdriver. On a narrow side 64 of the housing 60 composed of two housing half-shells 61, 62, recognizable by a joining line 63, the conductor insertion openings 66, 67 of the screw terminal 3 are accessible through corresponding housing recesses in the housing 60. While in the in Fig. 11 shown open state of the screw terminal 3, the upper conductor insertion opening 66 is completely open and the lower conductor insertion opening 67 is open with an opening height of approximately 1.5 mm, are in the in Fig. 12 shown closed state of the screw terminal 3, both conductor insertion openings 66, 67 are completely closed. In both states, however, the screw terminal 3 is prevented from being plugged underneath by the cover skirt S.

When the lower conductor insertion opening 67 is completely closed, as in Fig. 11 shown, the distance between the lower edge S1 of the cover skirt S and the upper edge 68K of the cover 68 formed on the housing 60 is smaller than the smallest possible diameter of a conductor end. The downward-pointing nose 15, which is formed centrally on the downward-pointing edge S1 of the cover apron S, ensures that the cover apron S does not thread out of the lower conductor insertion opening 67 in any part tolerance situation; in other words: the nose prevents the cover skirt S from getting in front of the cover 68. To achieve this effect, the entire lower edge of the cover skirt S could alternatively be extended to the lower edge of the nose 15, which would require more material than if only the centrally arranged nose 15 was formed. But a material-intensive extension of the entire cover apron S is not necessary, since the cover apron S does not have to hermetically seal the lower conductor insertion opening 67, but rather only has to prevent a conductor, which always has a certain minimum thickness, from being inserted underneath. The projection of the nose 15 downwards over the lower edge of the cover skirt S is therefore chosen to be approximately as large as the minimum diameter of a conductor end. By designing the guide element and unthreading protection as a nose 15, material is saved.

Fig. 13 shows a side view of an underplug protection part 1, which is pushed onto a clamping frame 2 of a screw terminal. To simplify the description, in Fig. 13 a right-handed Cartesian coordinate network is given. The under-plug protection part 1 has the shape of a closed frame with two longitudinal elements and two transverse elements connecting the longitudinal elements, of which in Fig. 13 a first longitudinal element L1 and the two transverse elements Q1, Q2 are visible. A first transverse element Q1 has a through opening A for passing through a screw shaft. A web 14 running in the z-direction is formed on the second transverse element Q2 and has a plate-shaped cover apron S that serves as under-plug protection extends in the xy plane. The clamping frame 2 has the shape of a closed frame with four frame elements, of which in Fig. 13 a first side part 22, a head bar 23 and a bottom bar 24 are visible.

The cover apron S is positioned on the under-protection part 1 in such a way that the lower edge S1, i.e. H. the side edge of the cover skirt S facing away from the first transverse element Q1, the lower edge 24UK of the floor web 24, d. H. the side of the bottom web 24 facing away from the head web 23, in a direction facing away from the head web 23, i.e. H. counter to the y-direction, by a support length b. The support length b is chosen so that the cover skirt S prevents a clamping chamber of a screw terminal from being inserted under it in all possible positions of the clamping frame 2.

This in Fig. 13 Under-plug protection part 1 shown differs from that in Fig. 1 shown underplug protection part 1 essentially in the following points: a) the web 14 of the in Fig. 13 Under-plug protection part 1 shown is attached to the underside of the second cross element Q2, whereas the web 14 of the in Fig. 1 illustrated underplug protection part 1 is attached to the front of the second cross element Q2; b) the in Fig. 13 Under-plug protection part 1 shown has no spring elements F; and c) the in Fig. 13 Under-plug protection part 1 shown has no nose 15 on the lower edge S1 of the cover apron S.

The under-plug protection part 1 is designed in such a way that its longitudinal elements L1, L2 are located approximately in the middle of the side parts 21, 22 of the clamping frame 2 and is plugged onto the under-plug protection part 1; That is, in a view of the clamping frame 2 against the x direction, the longitudinal elements L1, L2 divide the side parts 21, 22 of the clamping frame 2 into contact surfaces of approximately the same size, namely a front contact surface C1 and a rear contact surface C2. In these contact surfaces C1, C2, the clamping frame 2 supports the screw tightening torque, which is in a relatively high value range, e.g. b. at 3.5 Nm, can be in the housing 60. In the case of an off-center positioning of the under-plug protection part 1 on the clamping frame 2, it could happen that the screw tightening torque is supported via the under-plug protection part 1, which would be very disadvantageous and could lead to problems. Due to the central positioning of the under-plug protection part 1 on the clamping frame 2, the web 14 is necessary in order to attach the cover skirt S to the second cross element Q2 of the under-plug protection part 1.

Claims (12)

Under-plug protection part (1) for sliding onto a clamping frame (2) of a screw terminal (3), - wherein the under-plug protection part (1) has the shape of a closed frame which has two longitudinal elements (L1, L2) lying opposite one another and a first and a second transverse element (Q1, Q2), which lie opposite one another and each connect the longitudinal elements to one another, - wherein the first transverse element (Q1) has a through opening (A) for passing through a screw shaft and - A cover apron (S) serving as under-plug protection is molded onto the second transverse element (Q2). Under-plug protection part (1) according to claim 1, wherein the first cross element (Q1) forms a ring (10) which encloses the feed-through opening (A). Under-plug protection part (1) according to claim 1, wherein the first cross element (Q1) forms a semicircular arch (11) which encloses the through-hole (A) on three sides. Underpinning protection part (1) according to claim 3, wherein the semicircular arch (11) has a parting line (12) in the region of an arch apex of the arch. Under-plug protection part (1) according to one of the preceding claims, wherein the cover skirt (S) is designed as a plate which lies parallel to the plane spanned by the longitudinal and transverse elements (L1, L2; Q1, Q2). Under-plug protection part (1) according to one of the preceding claims, wherein at least one spring element (F) is formed on the second transverse element (Q2), which is designed such that an elastic deformation of the spring element (F), which occurs when the under-plug protection part (1 ) in a direction parallel to the longitudinal elements (L1, L2) in the direction from the first transverse element (Q1) to the second transverse element (Q2) occurs, leading to a restoring force in an opposite direction. Under-plug protection part (1) according to one of the preceding claims, produced by plastic injection molding. Screw clamp (3) in the manner of an elevator clamp, having - a clamping frame (2) with a head bar (23) and a bottom bar (24), which lie opposite each other, - a screw (30) which is screwably mounted in a threaded hole (26) in the head web (23), and - an underplug protection part (1) according to one of the preceding claims,
where - the underplug protection part (1) encloses the clamping frame (2), - the through opening (A) of the under-plug protection part (1) is arranged flush with the threaded hole (26) and - The cover apron (S) of the under-plug protection part (1) projects below the bottom web (24) in a direction facing away from the head web (23) (b). Screw terminal (3) according to claim 8, wherein the head web (23) carries a threaded flange on its outside facing away from the base web (24), which encloses the threaded bore (26), the first cross element (Q1) of the under-plug protection part (1) on its The side facing the second transverse element (Q2) along the through opening (A) has an inner corner on which the threaded flange rests. Screw terminal according to one of claims 8 or 9, wherein the screw terminal (3) is a double-chamber terminal. Screw terminal according to one of claims 8 to 10, wherein the under-plug protection part (1) sits on the clamping frame (2) in such a way that the two longitudinal elements (L1, L2) of the under-plug protection part (1) are side parts (21, 22) of the clamping frame (2), which each extend between the head web (23) and the bottom web (24), are each divided into contact surfaces (C1, C2) of approximately the same size. Installation device (60, 61, 62) with a screw terminal (3) according to one of claims 8 to 11.

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