Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
159 words
An overvoltage surge protector comprising a first electrode, a second electrode and a housing including means for maintaining the first electrode and the second electrode in spaced relationship to one another and electrically insulated from one another, the said electrodes each possessing a broad face and an external contact area, the broad face of said electrodes defining a gap therebetween, the gap so defined including at least a narrow portion and a contiguous wider portion wherein at least the said first electrode possesses a higher electrical resistance from the external contact area to the narrow portion of the gap than its electrical resistance from the external contact area to the wider portion of the gap CHARACTERIZED IN THAT at least the said first electrode consists essentially of a toroid of a predominantly carbonaceous material defining the narrow portion of the gap and a metal post defining the wider portion of the gap, within the central aperture of the toroid.
Claim 2
Dependent Claim
159 words
An overvoltage surge protector comprising a first electrode, a second electrode and a housing including means for maintaining the first electrode and the second electrode in spaced relationship to one another and electrically insulated from one another, the said electrodes each possessing a broad face and an external contact area, the broad face of said electrodes defining a gap therebetween, the gap so defined including at least a narrow portion and a contiguous wider portion wherein at least the said first electrode possesses a higher electrical resistance from the external contact area to the narrow portion of the gap than its electrical resistance from the external contact area to the wider portion of the gap CHARACTERIZED IN THAT at least the said first electrode consists essentially of a toroid of a predominantly carbonaceous material defining the narrow portion of the gap and a metal post defining the wider portion of the gap, within the central aperture of the toroid.
Claim 3
Dependent Claim
29 words
A device of claim 1 in which the resistivity of the carbonaceous material is at least 0.5 ohm-centimeters and the resistivity of the post is at most 0.005 ohm-centimeters.
Claim 4
Dependent Claim
20 words
A device of claim 2 in which the radial extent of the narrow gap region is less than 1 millimeter.
Claim 5
Dependent Claim
22 words
A device of claim 3 in which the radial extent of the narrow gap region is from 0.6 millimeters to 0.8 millimeters.
Claim 6
Dependent Claim
26 words
A device of claim 1 in which the wider portion of the gap is at least 100 percent wider than the narrow portion of the gap.
Claim 7
Dependent Claim
36 words
A device of claim 1 in which the metal post includes a flange extending radially under the toroid, whereby registry between the upper surface of the post and the upper surface of the toroid is maintained.
Claim 8
Dependent Claim
29 words
A device of claim 1 in which the carbonaceous material consists essentially of a baked mixture of lamp black and powdered petroleum coke with a coal tar pitch binder.
Claim 9
Dependent Claim
57 words
A device of claim 7 in which the mixture is (a) pressed to form a toroid; (b) baked in an oxidizing atmosphere at a temperature from 300° C. to 475° C. for at least one-half hour; and (c) baked in a reducing atmosphere at a temperature from 475° C. to 650° C. for at least one-half hour.
Claim 10
Dependent Claim
33 words
A device of claim 8 in which at least one pressed electrode, before baking, is caused to possess, at the gap defining surface, irregularities of a maximum height less than the gap width.
Claim 11
Dependent Claim
34 words
A device of claim 1 in which the metal post includes a body of a refractory metal with a melting point greater than 1800° C., at the gap defining surface of the metal post.
Claim 12
Dependent Claim
12 words
A device of claim 10 in which the refractory metal includes tungsten.
Claim 13
Dependent Claim
13 words
A device of claim 11 in which the refractory metal also includes copper.
Claim 14
Dependent Claim
12 words
A device of claim 1 in which the metal post is copper.