as that of the heat dam structure 186 the lower surface 160 of the wedge 150 rests on an upper surface 191 of the terminal block 190 accordingly the insulating section 144 is positioned between the heating section 142 and the body 102 slots 192 and 194 are provided in and pass through the terminal block 190 and are adapted to receive tabs 164 of the heating element 162 an open topped cylindrical hole 195 passes through the upper surface 191 of the terminal block 190 and receives a cylindrical bottom portion 196 of the heating element 162 spring contact members or electrical coupling members 197 and 198 see fig2 are attached to the terminal block 190 through cutouts 199 provided in the terminal block 190 adjacent opposite sides of the bottom portion 196 of heating element 162 and adjacent opposite contacts of the heating element 162 electrical lead 200 is adapted to be received by the terminal block 190 and held in place by spring contact 197 so that lead 200 is urged by spring contact 197 to touch contact 201 of the heater element 162 likewise an electrical lead 202 see fig2 and 3 is adapted to be received by the terminal block 190 and held in place by spring contact 198 see fig2 so that lead 202 see fig2 and 3 is urged by spring contact 198 to touch contact 203 of the heater element 162 a thermocouple or temperature sensor 204 is received by the thermocouple slots 118 and 155 and positioned adjacent the wedge 150 in.