Electricity: magnetically operated switches – magnets – and electr – Electromagnetically actuated switches – Polarity-responsive
Patent
1997-03-14
1999-09-14
Donovan, Lincoln
Electricity: magnetically operated switches, magnets, and electr
Electromagnetically actuated switches
Polarity-responsive
335177, 335132, 335128, 200533, H01H 5122
Patent
active
059529032
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to trip switches and particularly to a trip switch which can be used for domestic and light industrial use.
The present invention will be described in relation to the construction and operation of a trip switch incorporated in a residual current device (RCD). This description is for convenience only and it will be appreciated that the construction and operation of the mechanism are suitable for others uses.
RCD's are now well known and are usually provided with a first button by which the contacts are set, a flag which indicates the condition of the contacts by changing the colour of a window, and a second button which introduces into or simulates a fault in the circuit to prove that the device is working. The first button can set the trip switch by either engaging a mechanism or completing a circuit to allow an electrical closing of the contacts or a combination of both mechanical and electrical closing. Much effort has gone into reducing the size of RCD's but one area which has not been properly investigated is the area of the push buttons. The need for two push buttons tends to adversely effect of the size of the overall device since the buttons cannot be placed too close to each other nor can they be reduced in size having regard to the size of the human finger.
A detent mechanism prior to the present invention is disclosed in U.S. Pat. No. 4,409,574. This detent mechanism allows a single button to be used to test and to set a residual current device using a mechanism similar to that of the present invention. This mechanism has the disadvantage that it cannot be tested and set using a single depression of the button, as the state of the device is indicated by the distance that the push button extends from the main body at rest. This state cannot therefore be assessed when the button is being depressed.
FR 1,416,558 also discloses a mechanism for a tripping switch mechanism, but with the device disclosed the button needs to be rotated as well as pushed, and the mechanism cannot be tested and reset in a single depression.
According to the present invention, there is provided a push button residual current device a push button residual current device wherein a single push button is used to perform setting and testing operations on said device, and cause tripping and latching of a mechanism including power contacts of said device characterised in that:
said push button is arranged to be manually moved from a rest position to a second reset position, and
spring means are provided to return said push button from the reset position to its rest position, in order to latch said mechanism,
said push button being arranged to cause testing of a tripping mechanism on said device over a first part of its motion from the rest position to its second reset position.
The present invention has the advantage that a single push button is required for carrying out all the necessary operations on the device. This push button can therefore be much larger than the two or more buttons on previous residual current devices, making it much easier to use and preventing error caused by pushing the wrong button or pushing more than one button at once.
A specific embodiment of the invention will now be described by no way of example with reference to the accompanying drawings in which
FIG. 1 shows a diagrammatic sectional side view of a tripping and switch mechanism according to the present invention.
FIGS. 2A-2D show a first embodiment of a mechanism for operating a test function.
FIG. 3 shows a second embodiment of a mechanism for operating a test function.
FIGS. 4A-4C show an embodiment of a flag mechanism for the device of the invention.
FIG. 5 shows a further embodiment of the detent mechanism according to the present invention.
FIG. 6 shows the embodiment of FIG. 5 in a different condition.
FIG. 7 is a top view of a shorting bar contact device;
FIG. 8 is a sectional side view of the same shorting bar contact device; and
FIG. 9 is an isometric view of the shorting bar contact device.
Dealing firstly
REFERENCES:
patent: 3902032 (1975-08-01), Koepke
patent: 4409574 (1983-10-01), Misencik et al.
Donovan Lincoln
Nguyen Tuyen T.
Power Breaker PLC
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