Abstract An electrical impedance coil which has a helical configuration has applied to the outer surface thereof a plurality of circumferentially spaced bands of insulating material and which extend longitudinally of the coil. A cord wrapping applied around the bands at the helical interspace formed between adjacent turns of the coil serves to draw in those portions of the bands into this interspace so as to lie between adjacent turns and the bands in conjunction with the binding-in effect produced by the cord wrapping serve to mechanically reinforce the coil against disruptive forces which occur when the coil is required to carry high currents. A rotatable mandrel arrangement is provided in connection with manufacture of the coil, the mandrel serving to form the electrical conductor into helical form, and as a support for the supply rolls of the band material to be applied to the outer surface of the bands, after which the cord wrapping is applied as the mandrel is rotated.
An electrical impedance comprising a helically wound conductor coil, a plurality of bands of insulating material distributed over the outer surface of said coil in circumferentially spaced relation and which extend in a generally longitudinal direction of the coil, and a cord wrapping of insulating material applied to said bands at the portions thereof between adjacent turns of the coil and which serves to draw in those band portions so as to lie in the gap between the adjacent turns.
Claim 2
Dependent Claim
80 words
An electrical impedance comprising a helically wound conductor coil, a plurality of bands of insulating material distributed over the outer surface of said coil in circumferentially spaced relation and which extend in a generally longitudinal direction of the coil, and a cord wrapping of insulating material applied to said bands at the portions thereof between adjacent turns of the coil and which serves to draw in those band portions so as to lie in the gap between the adjacent turns.
Claim 3
Dependent Claim
20 words
A helically wound electricaL impedance coil as defined in claim 1 wherein said cord wrapping and bands are bonded together.
Claim 4
Dependent Claim
31 words
A helically wound electrical impedance coil as defined in claim 1 wherein said cord wrapping and bands are made from fiberglass and are bonded together by impregnation with a hardenable resin.
Claim 5
Dependent Claim
44 words
A helically wound electrical impedance coil as defined in claim 1 wherein said cord wrapping is constituted by a continuous cord member which extends from one end of the coil to the other in the helical space developed between adjacent turns of the coil.
Claim 6
Dependent Claim
43 words
A helically wound electrical impedance coil as defined in claim 1 wherein the thickness of said band material is considerably less than the distance between adjacent turns of the coil, and the interspace between coil turns is filled out by the cord wrapping.
Claim 7
Dependent Claim
48 words
A helically wound electrical impedance coil as defined in claim 1 wherein the distance between adjacent turns of the coil is essentially equal to twice the thickness of the band material so that the drawn-in portions of said material essentially fill out the interspace between the coil turns.