IL108702A

IL108702A - Protective circuit breaker

Info

Publication number: IL108702A
Application number: IL10870294A
Authority: IL
Original assignee: Siemens Ag
Priority date: 1993-03-19
Filing date: 1994-02-18
Publication date: 1998-08-16
Also published as: EP0616351B1; ES2088804T3; EP0616351A1; ATE138760T1; IL108746A; DE59302753D1; IL108746A0; IL108702A0; TR27419A

Abstract

A switching device, in particular a circuit breaker, such as a line protection circuit breaker, at least one of whose switching contacts (2, 3) is connected, as a moving contact (3) via a kinematic system (4) which may be part of a latching mechanism (5), to a manual operating device (6), and whose contact erosion can be compensated for by means of an adjustable excess movement. It is provided, that, in the kinematic system (4), one element interacts as a clamping lever (9) with the moving contact (3), in that the clamping lever (9) or moving contact (3) has, in a stiff basic structure (33, cf. FIG 9), a web which can bend out as an adjusting web (10) which rests, by means of an engagement body (11), on an associated bearing edge (12) when the contacts (2, 3) are in the open position. <IMAGE>

Description

Siemens Aktiengesellschaft Protective circuit breaker, preferably a line protective circuit breaker The invention relates to a protective circuit breaker, preferably a line protective circuit breaker, whose latching mechanism, which acts on at least one switching contact, can be unlatched by a thermal and, if necessary, a magnetic tripping device, for which purpose the tripping device acts on an unlatching device by means of a tripping lever. Such an arrangement is customary in protective circuit breakers, in particular in line protective circuit breakers.

The thermal tripping can be impaired by tolerances or by vibrations such as can be caused by shock or by being dropped. In this case, the assignment of the thermal tripping device as active element to the unlatching point, as a rule a half-shaft, from which a latch can glide off during unlatching, the passive element, can be impaired by various disturbing parameters. In order to keep such disturbances within limits, on the one hand the entire arrangement has been accommodated between plates or on the other hand an attempt has . been made by a complicated assembly and measures to achieve a suitable accommodation of the protective circuit breaker between the housing walls of a housing made from moulding material. However, such assembly is expensive.

It is the object of the invention to improve the protective circuit breaker of the type outlined at the beginning in such a way that even without plates and expensive assembly disturbing parameters can no longer appreciably impair the tripping response of the thermal tripping device.

The achievement of the object outlined takes place by means of a protective circuit breaker according to Patent Claim 1. In this case, the thermal tripping device is arranged in a holder which has a bearing which is freely rotatable in relation to the tripping lever of the unlatching device. The bearing is situated with its fulcrum on an imaginary straight line which passes through the bearing point of the thermal tripping device on the tripping lever and through the radius midpoint of the contour on the bearing point. The radius midpoint of the contour on the bearing point is termed the contour midpoint. Owing to the one fixed reference point for the thermal tripping device, more specifically owing to the fulcrum of the bearing of the thermal tripping device, on the one hand, and owing to the arrangement of the fulcrum and of the contour midpoint as well as of the bearing point on one straight line, on the other hand, the contour of the tripping lever and the geometrical location of the bearing points of the thermal tripping device on the tripping lever in a region on both sides of the provided bearing point correspond to such an extent that disturbing parameters cannot have an appreciable effect. The insensitivity with respect to disturbing parameters becomes higher the closer the contour midpoint and the fulcrum are situated together. In other words, the independence from disturbing influences becomes stronger the further the contour of the tripping lever and the geometrical location of the bearing points of the thermal tripping device also approach one another in a further region on both sides of the bearing point.

The holder for the thermal tripping device can advantageously also hold a magnetic tripping device. A particularly simple design results when in the case of a required magnetic tripping device the latter simulta-neously forms the holder for the thermal tripping device. The thermal tripping device can be designed in a customary way as a bimetal which acts on the tripping lever at the bearing point during the tripping state.

Disturbing parameters can have a particularly small effect when the fulcrum of the holder is designed to be particularly low-tolerance and stiff.

The invention is now to be explained in more detail with the aid of exemplary embodiments represented in a coarse diagrammatic fashion in the drawing, in which: FIGURE 1 shows a protective circuit breaker in side view and with the housing partially cut away, and FIGURE 2 reproduces a detail for one exemplary embodi- ment, specifically a specially configured tripping lever in conjunction with the geometrical location of the bearing points of the thermal tripping device, in the design as a bimetal.

The protective circuit breaker according to FIGURE 1 has a latching mechanism 1 which can be unlatched by means of a thermal tripping device 2. For this purpose, the thermal tripping device 2 acts on an unlatching device 3 by means "of a tripping lever 4. A magnetic tripping device 5 can also act in a known way, for example by means of a plunger armature 6 , on the unlatching device 3. When the unlatching device 3 is unlatched by a tripping device, the latching mechanism 1 opens a switching contact 7. 2 .

The thermal tripping device 3 is arranged in a holder 8 which has a bearing which is freely rotatable in relation to the tripping lever 4, it being the case that the holder 8 is situated with its fulcrum 9 on a straight line 10 which passes through the bearing point 11 of the thermal tripping device 2 on the tripping lever 4 and through the radius midpoint of the contour at the bearing point, termed the contour midpoint 12.

When the contour midpoint 12 and the fulcrum 9 are situated close together, as is illustrated in Figure 2, the contour of the tripping lever 4 and the geometrical location 13 of the bearing points 11 of a thermal tripping device, for example a bimetallic strip, largely correspond.

In the exemplary embodiment according to Figure 1 the magnetic tripping device 5 simultaneously forms in its total design the holder 8 for the thermal tripping device "3. It is favourable for the fulcrum 9 of the holder 8 to be designed to be particularly low-tolerance and stiff.

Claims

1. Patent claims Protective circuit breaker, preferably a line protective circuit breaker, whose latching mechanism HP) which acts on at least one switching contact^ jt¾ , can be unlatched by a thermal and, if necessary, a magnetic tripping device {^aaSf, for which purpose the tripping device acts on an unlatching device { f* by means of a tripping lever (4 , characterized in that - the thermal tripping device is arranged in a holder which has a bearing which is freely rotatable in relation to the tripping lever { ^> of the unlatching device , it being the case that the holder φίή* is situated with its fulcrum on an imaginary straight line (fbCty which passes through the bearing point of the thermal tripping device 4-B^»on the tripping lever (ofc and through the radius midpoint of the contour at the bearing point (≠te?T, termed the contour midpoint ffi&f.

2. Protective circuit breaker according to Claim 1, characterized in that the contour midpoint and the fulcrum &) are situated close together.

3. Protective circuit breaker according to Claim 1 or 2, characterized in that the holder of the thermal tripping device f& also holds a magnetic tripping device t£>) .

4. Protective circuit breaker according to Claim 1 or 2, characterized in that a magnetic tripping device †© forms the holder («β^ of the thermal tripping device (β^ .

5. Protective circuit breaker according to Claim 1 or 2, characterized in that the thermal tripping device («ity» is designed as a bimetal which acts on the bearing point ("3*4*) of the tripping lever { ) in the tripped state. Protective circuit breaker according to Claim 1 or 2, characterized in that the fulcrum of the holder jf&f is designed to be particularly low-tolerance and stiff. For the Applicants DR. REINHOLD COHN AND PARTNER?