SU1762323A1 - Limit switch - Google Patents

Abstract

Usage: in electrical engineering, in particular for switching electrical circuits. Summary of the invention: in a limit switch comprising fixed contacts, a housing with a permanent magnet fixed to it, a movable key and a ferromagnetic plate connected to it facing the permanent magnet, the movable contacts interact with the key by means of a spring. The spring is made twisted and placed between the movable key and the movable ferromagnetic plate.2 sludge.

Description

The invention relates to electrical current disconnectors, namely, end switches, and can be used in machine tool building and mechanical engineering.

A key switch is known, comprising a case of movable and fixed contacts, a key, a permanent magnet.

Known key switch, comprising a housing, a magnet rigidly connected to the housing, movable and fixed contacts, an elastic element.

The disadvantage of the key switch is low operational properties, short service life, design complexity.

The aim of the development is to increase the reliability of the switch, increasing the service life when switching higher currents.

The goal is achieved by the fact that the magnet has a rigid connection with the body, and the elastic element is made in the form of a twisted spring placed between the movable key and the ferromagnetic plate.

FIG. 1 shows a switch, a general view; in fig. 2 - the same in section.

The switch consists of a housing 1 (of a non-magnetic material) to which a magnet 2 of cylindrical shape is rigidly attached.

The key 3 can move relative to the magnet 2 and acts by means of an elastic element 4 on a ferromagnetic plate 5 of circular shape, to which movable contacts 6 are attached (there is no electrical connection between the contacts 6 and the ferromagnetic plate 5) to the end part of the magnet 2 rigidly fixed contacts 7

The principle of operation of the switch is as follows. When the key 3 is moved towards the magnet 2, the spring 4 is compressed to a certain threshold value when the forces of the deformable elastic element 4 are equal to the opposing forces of attraction of the ferromagnetic plate 5 to the magnet 2. Once the force of the deformable elastic element 4 exceeds the forces of CO

WITH

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plate 5 to magnet 2 there is a sharp separation of plate 5 from magnet 2 and, accordingly, movable contacts 2, which are rigidly connected to plate 5, from stationary contacts 7. There is an instantaneous break in the circuit of electric current through contacts 6 and 7. When forces are removed from keys 3 plate 5 is attracted to magnet 2 and contacts 6 and 7 close the circuit.

The location of the elastic element in the form of a coil spring between the movable key 3 and the ferromagnetic plate 5 provides an instantaneous break of the movable contacts from the fixed ones.

This reduces contact wear, extends the boundaries of use:

The limit switch can be used in electrical circuits with elevated currents.

Claims (1)

Invention Formula Limit switch containing a housing with a permanent magnet fixed on it, a movable key and a ferromagnetic plate connected to it facing the permanent magnet, fixed contacts and movable contacts interacting with the key by means of a spring, characterized in that, in order to increase reliability, the spring is made twisted and placed between the movable key and the ferromagnetic plate. / four J Fig1 Aa 7 2 FIG. 2