GB2045001A - High sensitivity polarised release device - Google Patents

Abstract

A high sensitivity polarised electromagnetic release device has a pivotable shaft 5 for a release catch 6 and a re-arming catch 7. The arrangement is such that when the device is being released the release catch 6 and the re-arming catch 7 are connected so that they are pivotally movable together and when the device is being re-armed the catches are individually pivotally movable. <IMAGE>

Description

SPECIFICATION High sensitivity differential switch The invention relates to improvements in polarised relays for use in high sensitivity differential switches, as in the Italian application No. 22465 A/77 filed 14th April, 1977 by the same Applicants. The present invention is intended to improve the intervention capacity of a polarised relay, while at the same time increasing the reliability, in use, of high sensitivity differential switches. Italian patent No. 22465 A/77 relates to a method of forming high sensitivity differential switches, and the said method also extends to the formation of the polarised relay, a device which preforms the important function of controlling actuation of the switch opening means in the case of current leakages.

For proper operation of the polarised relay it is necessary for a ferro-magnetic plate to arrive with a constant velocity on the polar ends of the relay; in this way secure adherence of the plate on said polar ends is guaranteed by the reason of the magnetic field, and more generally effective retention of the electro-magnetic properties of the polarised relay is ensured.

In the embodiment of the relay in accordance with the main patent, in normal operating conditions the release and re-arming pin does not act directly on the movement of the ferro-magnetic material plate.

The pressing action of the pin is in fact first applied to a releasing catch, with consequent liberation of a re-arming catch carrying the ferro-magnetic plate, the said re-arming catch being moved by the impetus applied thereto by a corresponding spring.

In this manner the speed of displacement of the ferro-magnetic plate is independent of the presssure force applied by the pin, and is kept constant during the traverse of the oscillating device.

These functional features of the device may however be altered by very high-speed re-arming of the polarised relay. In this case, rapid lowering of the re-arming pin would make the release tag directly contact the re-arming tag carrying the ferromagnetic plate. The latter would then no longer move under the constant force of the spring associated therewith, but with the velocity possessed by the re-arming pin: this velocity, not being controlled by any device, could mean failure to re-arm the polarised relay.

The oscillating device for re-arming the polarised relay, as improved in accordance with the invention, eliminates the above defects and is in essence characterised by permitting the release catch to engage with the re-arming catch only during the movement of said catches in the relay releasing phase.

According to the present invention there is provided an oscillating device, comprising tag pivoted on a shaft integral with the relay case, subjected to the downward force of a spring, functioning as a re-arming catch, a second tag pivoted on the same shaft integral with the relay case, subjected to the upward force of a spring, functioning as a release catch, the said two tags being simultaneously connected together during the osciilation phase towards release of the relay and independently in the rearming phase.

These and further features of the invention will appear from the following description relating by way of example to a non-limitative preferred embodiment of the oscillating device for re-arming the polarised relay illustrated by the representations in the attached sheets of drawings wherein:- Figure 1 is a sectional view of the polarised relay in release position; Figure 2 is a view corresponding to Figure 1 with the polarised relay during the relay re-arming phase; Figure 3 is a view corresponding to Figure 1 with the relay in re-arming position; and Figure 4 is a view corresponding to Figure 1 with the relay ready for the release phase.

The polarised relay consists of a case 1 stamped from insulating material, within which is disposed the permanent magnet 2, the coil 3, the oscillating device (to be described in detail below), and the pin 4 for releasing the re-arming.

The oscillating device comprises a shaft 5 integral with the case 1 of the polarised relay and on which are privoted the release tag 6 and the re-arming tag 7.

This re-arming tag 7 is connected to the ferromagnetic plate 8, said plate 8 being held between the side and top walls and held in position by a support strip 9 affixed to the re-arming tag 7.

The re-arming tag 7 is also provided with projecting arms 7' integral therewith (Figures 2, 3) and which are hinged on shaft 5 by means of suitable slots provided at their ends. A re-arming spring 7" also has the function of imparting to tag 7 a constant velocity in the direction of the polar ends of the relay.

On the same shaft 5 and below the tag 7 is hinged a release tag 6: this latter tag is free to rotate anti-clockwise without interfering with the re-arming tag 7. The release tag 6 is also associated with a release spring 6' with the function of urging upwards the tag 6 itself.

During the release phase of the polarised relay the tag 6 is raised by the spring 6', and during this upward movement also entrains the re-arming tag 7, this latter action being effected by means of suitable projections (not shown in the drawings) provided on the internal surfaces of the arms 7' of the re-arming tag 7.

The re-arming tag 7 is also held in position by the pressure force applied by spring 6' of the release tag 6 which abuts against the tag 7 in correspondence with the said projections formed on the arms 7'.

During the fast-moving re-arming phase and starting from the described relay release position (Figure 1), the pin 4 presses strongly on the upper part of release tag 6; the latter swings downwards without interfering with tag 7 during its descent (Figure 2, 3).

The pin 4 also passes freely through the free space between the arms 7' thus avoiding any direct transmission of its movement to the re-arming tag 7, so that the relay is then ready for the release phase (Figure 4).

In an alternative embodiment (not shown) the tag 6 may be disposed above tag 7, but in this case should be of lesser length than the arms 7' of the said tag 7.

Claims (5)

1. An oscillating device for re-arming the polarised relay of a differential switch as described in the main patent (application 22465 A/77) in the name of the same Applicants, characterised by permitting the release catch to engage with the re-arming catch only during movement of said catch in the relay release phase.

2. An oscillating device for re-arming the polarised relay, as in claim 1, characterised in comprising a tag pivoted on a shaft integral with the relay case, subjected to the downward action of a spring, functioning as a re-arming catch, a second tag pivoted on the same shaft integral with the relay case, subjected to the upward force of a spring acting as a release catch, the said two tags being simultaneously connected together during the oscillation phase towards release of the relay, and independently in the re-arming phase.

3. An oscillating device for re-arming the polarised relay, as in claims 1 and 2, characterised in comprising a re-arming tag whose arms are pivoted on a shaft integral with the relay box, a release tag disposed below the tag being pivoted on the same shaft.

4. An oscillating device for re-arming the polarised relay, as in the preceding claims, characterised in that the release tag is disposed above the re-arming tag and has a length less than that of the arms of the tag.

5. An oscillating device substantially as hereinbefore described with reference to the accompanying drawings.