Abstract: A torque detection device includes a first yoke and a first magnetic guide member. A first opposing portion of the first magnetic guide member overlaps with a first-yoke ring of the first yoke when the first-yoke ring is projected onto the first opposing portion in an axial direction. Furthermore, the first opposing portion overlaps with an inner surface of a second tubular portion when the inner surface is projected onto the first opposing portion in the axial direction. A housing distance, which is a shortest distance measured from the first opposing portion to the inner surface, is longer than a yoke distance, which is a shortest distance measured from the first opposing portion to the first-yoke ring.

Abstract: A heat treatment vessel coupler for coupling together heat treatment vessels adjacent in a horizontal direction, of a plurality of rectangular box-shaped heat treatment vessels each loaded with a material to be treated, conveyed in a conveying direction on a plurality of rotationally driven conveyor rollers arranged in parallel inside a heat treatment furnace, the coupler comprises a plate body smaller than each of the heat treatment vessels, at least a pair of engagement protrusions each projecting from the plate body and engaging with a corresponding one of side walls of the heat treatment vessels, and a spacer protrusion projecting from the plate body between the at least a pair of engagement protrusions so as to be sandwiched between the heat treatment vessels with which the at least a pair of engagement protrusions engage respectively.