Electricity: circuit makers and breakers – Interlocking – Between plural switches
Patent
1989-08-01
1991-04-23
Scott, J. R.
Electricity: circuit makers and breakers
Interlocking
Between plural switches
200 6162, H01H 922
Patent
active
050102150
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
This invention relates to a switch actuating mechanism and more particularly to an electric switch mechanism for use in association with an electric switch for monitoring the position of a fluid control valve.
In various fire sprinkler installations it is considered at least desirable and in some instances compulsory due to legislation to monitor that various valves of the hydraulic system are in a normal operating position and are not in some other position that might render them ineffective.
Thus, a water supply line for a sprinkler system may be fitted with an on-off valve which can be put to the off position for various maintenance reasons. However, for the sprinkler system to be effective that valve must be returned to the on position after the maintenance is completed. Since errors might occur it has become at least desirable that a means is provided for monitoring whether that valve is in the on or off position. Such monitoring may be conducted remotely such as at a distant fire station.
It is relatively easy matter to provide an electrical circuit incorporating a switch which can be actuated by some movement of a valve operator to become an open or closed circuit. However, maintenance on the switch itself may be required or the switch may need to be removed for some reason and it is conceivable that a human error might occur rendering the sprinkler system unable to operate but which, to a casual observer, appears to be in full working order.
In many other instances besides fire sprinkler systems similar problems may arise such as at oil refineries and on ships.
SUMMARY OF THE PRESENT INVENTION
Accordingly, the present invention seeks to provide a switch having a self disabling feature when various work is done on the switch itself.
The present invention provides an electrical switch mechanism comprising a housing, a switch actuator within the housing, biasing means biasing the switch actuator towards a first position, an operator member adapted to undergo a movement to cause the actuator to move against said biasing means to a second position, a removable access cover for providing access within the housing and means responsive to removal of said cover adapted to put the mechanism in a condition such that said movement is incapable under normal conditions of use of moving the actuator to said second position.
BRIEF DESCRIPTION OF THE DRAWING
A specific construction of a switch incorporating a switch mechanism in accordance with the present invention will now be described with the aid of the accompanying drawings in which:
FIG. 1 is a perspective view of a switch housing incorporating a switch actuating mechanism, with the cover removed;
FIG. 2 is a cross-sectional view on the line 2--2 of FIG. 1;
FIG. 3 is a cross-sectionl view on line 3--3 in FIG. 1;
FIG. 4 is a view similar to FIG. 3 showing the mechanism in the inoperative position;
FIG. 5 is a fragmentary view similar to FIGS. 3 and 4 showing the cradle for the actuator; and
FIG. 6 is a view similar to FIG. 5 showing the floating action of the actuator.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The switch shown in the drawings comprises a housing comprised of a body 1 and a cover 2. The body 1 has an access hole 3 for electrical cable and mounting lugs 4.
Within the body is a partition 6 which divides the body into a connections chamber 7 and a switch chamber 8.
In use of the switch a terminal block 55 is provided in the connections chamber 7 and wires of a cable 57 which pass through the hole 3 are connected to the terminal block 55 and further wires 59 pass from the terminal block 55 to a switch 5. The wires 59 to the switch 5 are embedded in a sealant compound (not shown) which also serves to seal the chambers 7 and 8 from one another.
The switch 5 is a normally open circuit switch and is provided with a plunger 23.
The plunger 23 can be moved by end 61 of a pivoted actuator 24 which is mounted to pivot on pivot pin 26 (FIG. 2). The pivoted actuator 24 is biased by a spring 27 so that the switch 5 is in i
REFERENCES:
patent: 1515206 (1924-11-01), Huey
patent: 2452403 (1948-10-01), Stukart
patent: 4703147 (1987-10-01), Happ et al.
Anthony Mark C.
Farrell Jonathon E.
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