Heater and method of manufacturing same

Abstract

Provided is a heater in which heater patterns are provided in parallel between terminals. Each terminal is divided into a divided terminal having electrical conduction only with one heater pattern, and a divided terminal having electrical conduction only with the other heater pattern. After a heater body is fabricated, in a state prior to mounting a feed bolt, resistance adjustment is performed with respect to each of a virtual series path formed between the divided terminals and a virtual series path formed between the divided terminals. Then the feed bolt is mounted to each terminal, whereby a plurality of virtual series heater patterns are placed in electrical conduction with each other, thus forming a parallel circuit.

1 . A parallel-type heater wherein a plurality of heater patterns are formed in parallel between a pair of terminals to which power supply bolts are fitted respectively the parallel-type heater comprising:
 each of said pair terminals is divided into a plurality of spaced segmental terminals of the same number as said plurality of heater patterns, said plurality of segmental terminals being electrically connected with each other by said power supply bolt,   a plurality of imaginary serial heater patterns arc formed between one of said segmental terminals divided from one of said pair of terminals and one of said segmental terminals divided from the other pair of terminals when said power supply bolts are not yet fitted, said plurality of imaginary serial heater patterns being electrically connected with each other to form parallel circuits when said power supply bolts are fitted.   
     
     
         2 . The parallel-type heater of  claim 1  wherein a head of said power supply bolt is in contact with a heater element forming said heater pattern directly or via a washer made by conductive material. 
     
     
         3 . The parallel-type heater of  claim 1  wherein first and second heater patterns are formed in parallel between a pair of said pair of terminals, each terminal being divided into a first segmental terminal to be electrically connected only with a first heater pattern of said plurality of heater patterns and a second segmental terminal to be electrically connected only with a second heater pattern of said plurality of heater patterns. 
     
     
         4 . The parallel-type heater of  claim 3  wherein each of said first and second segmental terminals is formed in substantially a semicircular ring shape, said first and second heater patterns being insulated with each other by a gap extending in a radial direction between said segmental terminals. 
     
     
         5 . The parallel-type heater of  claim 1  wherein first to fourth heater patterns are formed in parallel between the pair of said terminals, each terminal being divided into a first segmental terminal to be electrically connected only with said first heater pattern, a second segmental terminal to be electrically connected with said second heater pattern, a third segmental terminal to be electrically connected with said third heater pattern and a fourth segmental terminal to be electrically connected only with said fourth heater pattern. 
     
     
         6 . The parallel-type heater of  claim 5  wherein each of said first to fourth segmental terminals is formed in substantially a quadrant ring shape, said first to fourth heater patterns being insulated with each other by gaps extending in radial and circumferential directions between said segmental terminals. 
     
     
         7 . A production of the parallel-type heater of  claim 1 , comprising:
 producing a heater body having a plurality of heater patterns in parallel between a pair of terminals,   performing resistance adjustment for each of said imaginary serial heater patterns formed between one segmental terminal of one terminal and one segmental terminal of the other terminal before fitting said power supply bolts to said terminals, and   then fitting said power supply bolts to said terminals so that said plural imaginary serial heater patterns become electrically connected with each other to form a parallel circuit.