Interlock switch
AssigneeNCR Corporation
InventorMark G. Pipkorn
Life of this patent
Estimating the term…
Abstract
An interlock switch for the service door of a computer. The switch prevents power from being automatically resupplied to the computer if the door is opened while power has been interrupted, even if the door is subsequently closed. The interlock switch includes a magnetic reed switch, an electromagnet for closing the reed switch contacts when the power-on switch of the computer is actuated, and a permanent magnet which holds the reed switch contacts closed as long as the service door has not been opened. The reed switch and electromagnet are mounted on the frame of the cabinet of the computer. The permanent magnet is mounted on the edge of the service door adjacent the reed switch. The use of the switch in a security system is also disclosed.
Claims15
An interlock switch for operatively connecting a power source to an electrical load, comprising:
- switch contacts having a first position and a second position, said contacts for being moved from said first position to said second position in response to a magnetic field;
- first magnetic means for generating a first magnetic field when the power source is connected to the load, said first magnetic field causing said contacts to move from said first position to said second position;
- and
- second magnetic means having a first position and a second position and for generating a second magnetic field, said second magnetic field causing said contacts to be held in said second contact position when said second magnetic means is in said first position and being insufficient to hold said contacts in said second contact position when said second magnetic means is in said second position.
An interlock switch for the service door of an electrical appliance, said interlock switch disconnecting the appliance from an electrical energy source when the door is opened, said interlock switch comprising:
- a magnetic switch having a first position where the appliance is connected through said magnetic switch to the energy source and a second position where the appliance is not connected through said magnetic switch to the energy source;
- an electromagnet for generating a first magnetic field when electrically energized, the magnetic field causing said magnetic switch to move from said second switch position to said first switch position to thereby connect the appliance to the energy source;
- a magnet supported in the appliance for generating a second magnetic field, the second magnetic field sufficient to hold the magnetic switch in the first switch position after it has been moved to the first switch position by the magnetic field of said electromagnet, and also supported in the appliance to move in relation to said magnetic switch when the service door is opened, so that when the magnetic switch has been moved to the first switch position by the first magnetic field, the second magnetic field of said magnet will hold the magnetic switch in the first switch position if said electromagnet ceases to be energized, but thereafter will not hold said magnetic switch in the first switch position if the service door is opened, thereby disconnecting the appliance from the electrical energy source.
A switch responsive to relative movement of a first structure and a second adjacent structure, said switch comprising:
- two electrical contacts having a first position and a second position, said contacts being moved from said first position to said second position in response to a magnetic field of a first predetermined level and capable of being held in said second position by a magnetic field of a second predetermined level;
- first magnetic means responsive to an electrical signal for generating a magnetic field of the first predetermined level and thereby causing said contacts to move from said first position to said second position;
- and
- second magnetic means for generating a magnetic field of the second predetermined level, said contacts located at one of said first and second structures, said second magnetic means located at the other of said first and second structures, so that upon relative movement of said first and second structures away from each other, said contacts go from a condition where the magnetic field of the second predetermined level from said second magnetic means is provided to said contacts and holds said contacts in said second position, to a condition where the magnetic field of the second predetermined level is not provided to said contacts and said contacts return to said first position.
Dependencies are inferred from the claim text.