AU600465B2

AU600465B2 - Protective conductor connection terminal

Info

Publication number: AU600465B2
Application number: AU67910/87A
Authority: AU
Inventors: Zdenek Krec
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 1986-01-23
Filing date: 1987-01-22
Publication date: 1990-08-16
Anticipated expiration: 2007-01-22
Also published as: EP0233458B1; EP0233458A1; DE3770949D1; AU6791087A; ATE64798T1

Abstract

A protective cable terminal (1), particularly in a series terminal housing whose base (2) is used as a strain-relief clamp and has supports in a deep, and in a flat cut-out (3; 4) for supporting on carrier rails (5) of cap-shaped cross-section, and which holds a compression spring (6) which is prestressed by means of sliding zones (7, 8) against cut-outs (3, 4) and is stressed on being placed on a carrier rail, in order to make contact. According to the invention, it is provided that, as a result of its shape with respect to the cut- outs (3, 4) in the base (2), and with respect to supports (11, 12) on the base (2), when the base is placed with the deep cut-out (3) on a carrier rail, the compression spring (6) and a movement of the base (2) stress the rail, which results in engagement of the edge of the rail with the flat cut-out (4), as a result of a force component parallel to the plane of the rail. <IMAGE>

Description

SBR/TGK/151W 4~1~1 0 0 4g6 FORM 10 SPRUSON FERGUSON COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952 COMPLETE SPECIFICATION

(ORIGINAL)

FOR OFFICE USE: 67 9/o 027 Class Int. Class Complete Specification Lodged: Accepted: Published: Priority: Related Art: dTuis d a211iiiiit cot,ljrIF the J mnnd ient s made nr Scctioi .49 and is tA'rreLL. i O Name of Applicant: Address of Applicant: Actual Inventor: Address for Service: SIEMENS AKTIENGESELLSCHAFT Wittelsbacherplatz 2, D-8000 Munchen 2, Federal Republic of Germany ZDENEK KREC Spruson Ferguson, Patent Attorneys, Level 33 St Martins Tower, 31 Market Street, Sydney, New South Wales, 2000, Australia Complete Specification for the invention entitled: "PROTECTIVE CONDUCTOR CONNECTION TERMINAL" The following statement is a full description of this invention, including the best method of performing it known to us SBR/TGK'lS1W

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SFP4 To: The Commissioner of Patents Signature of Declarant(s) 11/81 -2bE- C2 (26 3s3 QWest German Patent Application No. P 3526494.2, .h w.c not yet pu1ihe d on 23rd January, 1936, discloses a protective conductor connection terminal, more particularly in a terminal block housing, the foot of which terminal serves as a tensioning clamp and has a deep recess and a shallow recess, which recesses are to receive opposite edges of an electrically conductive bearing rail, on which the terminal is to be supported, the cross-sectional shape of the rail being like that of the kind of hat which is known as a boater, the foot holding a pressure spring, slide-over zones of which are biased towards the recesses, the spring being tensioned when mounted on a bearing rail in order to make good electrical contact between the terminal and the rail. The pressure spring has a rounded end which stands up on an edge of the rail in the deep recess.

An external additional spring, which is pre-formed on the terminal, is applied, in the deep recess, laterally against one edge of the bearing rail when the rail has been introduced and presses the terminal away from the rail so that the shallow recess can receive in it the other edge of the rail, whereby the terminal is secured on the bearing rail. The pressure spring is formed in the transition to its end at the shallow recess in such a way that there is a slide-over zone of the spring, which slides over the inner edge of the bearing rail so that the pressure spring slides over like a wedge against the rail edge and abrades insulating dirt or oxide layers. In this way good electrical contact between the rail and the terminal is achieved.

West German Patent Specification No. 3126535 discloses an electrical terminal block which is developed as a protective conductor connection terminal, in which a pressure clamp under the force of the terminal screw of an electrical connection terminal presses against an edge of a bearing rail inserted into PAV3 1 Ar -3the recesses of the tensioning clamp. The electrical contact between the rail and the terminal is then to be achieved by means of teeth on a part of the terminal recess which is an abutment for the edge of the rail in the tensioning clamp.

West German Patent Specification No. 3339365 discloses another protective conductor connection terminal in which the terminal screw of an electrical connection terminal for the protective conductor presses against one arm of a rocker lever, another arm of which presses an edge of the rail against the foot of the terminal.

In the case of the known protective conductor connection terminals, where the terminal screw for the purposes of connection of the electrical protective conductor presses the terminal on the bearing rail, the protective conductor connection terminal when mounting the bearing rail does not, in the first instance, find any secure hold, and this is troublesome during installation. In the case of the protective conductor connection terminal of West German Patent Specification No.

DE-C2-3,126,535, a secure hold on the bearing rail is, it is true, achieved irrespective of the terminal screw, although for this purpose an additional spring is used.

In accordance with the present invention there is disclosed electrical apparatus for detachably mounting an electrical terminal unit to a substantially U-shaped electrical conductive rail having opposed first and second outwardly directed longitudinally extending flanges, said apparatus comprising an electrically conductive base of an electrical terminal unit and associated electrically conductive spring means for use in detachably mounting said unit onto said rail; wherein said base has corresponding first and second spaced apart recesses each having an Qelc o4 er open-end facing-the-u up.e, said first recess being deeper than said second recess, said spring means being detachably anchored to said base and having first and second sections located adjacent said first and second recesses respectively; and wherein said apparatus is mountable upon said rail by the engagement of said first flange with said first recess to abut said first section and said first flange to thereby resiliently urge said first section away from said first recess and clamp said first flange -e-ej-within i

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IA 540 7 IA -IN O -4said first recess, and by moving the open end of said second recess into alignment with said second flange to thereby abut said second section against said second flange to resiliently urge said second section away from said rail, and sliding said base to substantially fully engage said second flange and second recess whereby said base and rail are positioned by interengagement of said recesses and flanges and clamped by said first and second sections of said spring means to ensure good electrical conduction between said base and rail.

The over-slide zones are here aligned so that the pressure force of the tensioned pressure spring has a component which is directed parallel to the rail plane to the shallow recess and draws, in counteraction with the rail, the foot with the shallow recess onto the y: IAD 4o Ul~F 1 -*lc clura, rail edge. The sliding movement on the over-slide zone allows, at the same time, dirt or oxide layers to be abraded so that electrical contact is guaranteed.

The protective conductor connection terminal can produce the forces to transfer its foot into a secure hold on the bearing rail according tc claim 9 alone at the deep recess, acc#rding to claim 10 alone through the over-slide zone at the shallow recess or a-eeerd4ng to claim 11 through mutual support.

If the pressure spring is held in flanks of the foot through lugs in windows, said lugs engaging in the window with clearance, tolerance in respect of bearing rails can be guaranteed.

When the pressure spring is made of round wire, the mechanical resistance is reduced when there is over-sliding and, on the other hand, the electrical contact is improved.

When the deep recess in the foot of the protective conductor connection terminal according to form and inclination of the rest for the rail edge makes oblique mounting on a bearing rail possible, the mounting and removal are facilitated. On the other hand, in this way as well a visual indication is given of which terminal has been mounted and which terminal has only been put on loosely.

There is only one spring in the examples described below.

The invention shall now be explained in greater detail with the aid of exemplary embodiments reproduced roughly diagrammatically in the drawings, Figure 1 reproduces a protective conductor connection terminal with housing cut open.

Figure 2 reproduces a foot of one type of construction in a side view, which foot can be part of

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-6- 1 a protective conductor connection terminal according to Figure 1 or another connection terminal.

In Figure 3 a view from below of the foot according to Figure 2 is represented.

Figure 4 illustrates how the foot according to Figure 2 is mounted with tension of the pressure spring.

Figure 5 represents the foot latched onto a bearing rail.

Figure 6 reproduces an inclined foot. In this position the foot is being released. It can also be brought into this position when being mounted.

Figure 1 illustrates a protective, conductor io OaCorda nce terminal, the foot of which is constructed -aee-rding The protective conductor connection terminal 1 has a foot 2 which forms a strain-relief clamp for the purposes of securement on a bearing rail. To this purpose, it has, in a deep recess 3 and also in a shallow recess 4, rests for the purposes of support on bearing rails 5, which are top hat-shaped in cross section according to Figure 4. The strain-relief clamp holds a pressure spring 6 which is presprung with over-slide zones 7, 8 against the recesses 3, 4.

When the protective conductor connection terminal 1 is mounted upon a bearing rail, it is tensioned, whereby electrical contact is also guaranteed. The protective conductor connection terminal 1 according to Figure 1 is, in the exemplary embodiment, part of a series terminal with further connection planes 9 and It is essential that the pressure spring 6 be tensioned through its form in respect of the recesses 3, 4 in the foot 2 and with regard to abutments 11, 12 on the foot 2 when mounting the foot with the deep recess 3 on a bearing rail. Under the force of the tensioned pressure spring, displacement of the foot 2 then results until the rail edge is embraced with the shallow recess 4.

L Y __II I -7- 1 This gives rise, in each case, to a force component of the spring parallel to the rail plane in counteraction with the rail.

Windows 14 are recessed as mounting support for the pressure spring 6 in a foot 2, which is bent so that it is U-shaped in cross sectioq according to Figures 2 and 3 in its flanks 13. Lugs 15 of the pressure spring 6 engage into said windows 14, clearance being left so that the pressure spring 6 remains so that it may be displaced somewhat in the foot 2 in the latter's longitudinal direction. The pressure spring 6 is formed of round wire which is bent over at one end and which is guided back over the whole length of the spring, as can be seen from Figure 3. Spring steel not only has the advantage of strong pressure forces, but also gives rise to little friction and good contact as the pressure spring when sliding on a bearing railvigorously abrades dirt and oxide layers in a narrow channel of action.

Figure 4 illustrates how a protective conductor connection terminal with two over-slide zones 7 and 8 with its foot 2 is mounted on a bearing rail 5. A bearing rail edge is set into the deep recess 3.

The pressure spring 6 is supported between its mounting support, window 14, in the foot and the deep recess 3 against an abutment 11 on the foot. It engages into the deep recess 3 with its rounded end, the vertex 16 still lying beyond the rail edge in a position raised by the rail thickness. As a result the pressure spring 6 is applied at the rail edge in an imaginary overslide plane 17. As a result a spring force component takes effect, which component is horizontal and is orientated on the basis of the drawing, pushes the foot 2 off against the rail edge and as a result draws the shallow recess 4 onto the other rail edge.

When the pressure spring 6 is tensioned it -8passes from one position according to Figure 2 to a position according to Figure 4. The other rail edge hereby slides,in the case of the shallow recess,along the incline 18 of the foot. When the protective conductor connection terminal according to Figure 5 -is latched on the bearing rail, the end of the pressure spring 6 is supported agaiist an abutment 12 on the foot. This abutment is, viewed in the foot's longitudinal direction, arranged close to the rest 19 of the pressure spring 6 at the rail edge in order to form a rigid spring for the seat of the terminal and for making contact. The pressure spring is then raised by the rail thickness.

The pressure spring 6 can be supported at least already shortly before against the abutment 12 in order to intensify the spring force.

When the pressure spring 6 between the shallow recess 4 and the position of the adjacent inner rail edge 20 of an inserted bearing rail has an over-slide zone 8 according to the exemplary embodiment in an over-slide plane 21 running obliquely in respect of the rail edge according to Figure 4, the foot can be latched as a result with the shallow recess 4 onto a bearing rail. This over-slide zone at the shallow recess here supports the action of the over-slide zone at the deep recess.

The end of the pressure spring 6 between the rest 19 according to Figure 5 at the rail edge and the abutment 12 on the foot 2 supplies substantial holding forces for the protective conductor connection terminal when the latter is latched on a bearing rail. Further holding forces are supplied by the other end of the pressure spring 6 as a function of the length between the abutment 11 on the foot 2 and the rest in the overslide plane 17 at the rail edge, in conjunction with the clamping position in the window 14. The forces, which ensure that the foot is drawn on the rail edge with its shallow recess 4, are yielded by the over- -9- 1 slide planes 17 and 21. It is sufficient if one of the over-slide planes 17 and 21 can become effective. When there are two over-slide planes these can assist each other.

It is favourable if, according to Figure 6, the deep recess 3 in the foot 2 through form and/or inclination of the rest 22 for the rail edge renders possible oblique mounting on the bearing rail. This position can be reached more particularly when the foot 2 is released from the bearing rail 5 through lateral pressure on the rail edge at the deep recess 3. If an over-slide zone 8 is developed on the pressure spring 6 before its opposite end, the inclination of the foot according to Figure 6 can also be allowed for the installation as the over-slide zone 8 then guarantees that the foot 2 is drawn on and heldsecurely during installation.

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Claims

1. Electrical apparatus for detachably mounting an electrical terminal unit to a substantially U-shaped electrical conductive rail having opposed first and second outwardly directed longitudinally extending flanges, said apparatus comprising an electrically conductive base of an electrical terminal unit and associated electrically conductive spring means for use in detachably mounting said unit onto said rail; wherein said base has corresponding first and second spaced apart recesses each having e'c o0+e'c an open-end facing- -h pper, said first recess being deeper than said second recess, said spring means being detachably anchored to said base and having first and second sections located adjacent said first and second recesses respectively; and wherein said apparatus is mountable upon said rail by the engagement of said first flange with said first recess to abut said first section and said first flange to thereby resiliently urge said first section away from said first recess and clamp said first flanged-eep within said first recess, and by moving the open end of said second recess into alignment with said second flange to thereby abut said second section against said second flange to resiliently urge said second section away from said rail, and sliding said base to substantially fully engage said second flange and second recess whereby said base and rail are positioned by interengagement of said recesses and flanges and clamped by said first and second sections of said spring means to ensure good electrical conduction between said base and rail.

2. Apparatus as claimed in claim 1 wherein said spring means is anchored to said base by a third section and has fourth and fifth sections that press against abutment surfaces of said base, said first, fourth, proc44_i 9 third, fifth and second sections p.reedi4g -along said spring means in that order.

3. Apparatus as claimed in claim 1 or 2, wherein said base comprises two parallel plate-like portions, one or both of said portions being electrically conductive, and each having an upper edge joined to the other, said portions being formed with corresponding said first and second recesses, said portions being spaced apart to define a groove open at said recesses, said spring means being located within said groove. IA[ 54o r 'r o: LT 0 11

4. Apparatus as claimed in claim 3, wherein said spring means comprises a wire spring bent to form two substantially parallel limbs each of which being anchored in a window formed in the adjacently associated plate-like portion.

Apparatus as claimed in claim 4, wherein said spring is anchored to said plate-like portions by bent-out portions of said limbs engaging in respective windows of said plate-like portions.

6. Apparatus substantially as described herein with reference to Figs. 1 to 6 of the drawings.

7. An installation comprising the apparatus as claimed in any one of claims 1 to 6. DATED this TWELFTH day of APRIL 1990 Siemens Aktiengesellschaft Patent Attorneys for the Applicant SPRUSON FERGUSON RAD IA6 ~854o