Abstract: A die for extruding honeycomb structural bodies includes a plurality of ceramic batch exhaust grooves and a plurality of ceramic batch supply apertures. Tubes are fitted in at least some of the ceramic batch supply apertures to improve or make constant the surface roughness and dimensions of inner surfaces of ceramic batch supply apertures through which the ceramic batch passes, thereby producing perfect ceramic honeycomb stuctural bodies. The adjustment of flow of ceramic batch is so simplified that any other controlling plate which would be required in the prior art is not needed for controlling the flow. When the supply apertures have been worn off, the tubes are exchanged by new ones to restore the required inner surfaces easily.

Abstract: An improved synthetic resin insulator comprising a reinforced plastic rod and a holding metal fitting having a sleeve is disclosed. In the insulator, the reinforced plastic rod is firmly secured to the sleeve of the holding metal fitting by a divided die means including at least five pieces, wherein the rod is inserted into the sleeve and the outer surface of the rod is substantially uniformly compressed in the centripetal direction by the inner surface of the sleeve by pressure exerted by each of the five divided die means pieces, so that the outer circumference of the rod is uniformly compressed at an optional cross-section thereof. The insulator is free from cracks and whitening in the rod and has an improved durable life.

Abstract: A heat resistant and thermal shock resistant ceramic honeycomb catalytic converter for purifying automotive exhaust gas and the like is constructed by arranging at least one ceramic honeycomb structural body, having a dimension of0.10.ltoreq.L/D.ltoreq.0.40wherein L and D are respectively a length and a diameter of the ceramic honeycomb structural body, upstream of and adjacent to another ceramic honeycomb structural body in a metal casing.

Abstract: This invention discloses ceramic honeycomb structural bodies having high thermal shock resistance and mechanical strength in which partition walls forming numerous parallel channels of the honeycomb structural bodies and/or connecting portions of the partition walls are constructed so as to have flexibility. The flexibility allows thermal stress generated in the honeycomb structural bodies to be absorbed. The bodies are characterized in that a given area of outer circumferential annular portion of said ceramic honeycomb structural bodies has a structure having a higher rigidity than the inner portion.

Abstract: A ceramic honeycomb structural body to be used in an automobile monolith catalyst converter in which the ceramic honeycomb structural body having numerous parallel channels are clamped by annular supporting members perpendicular to axis of said channels has such a structure that end surfaces of the ceramic honeycomb structural body are more strongly clamped at an inner circumferential portion of the above described annular supporting members than at the outer circumferential portion of said annular supporting members. Such a ceramic honeycomb structural body is stably held in the catalyst converter without forming break at the peripheral portion of the end surface of the honeycomb structural body.

Abstract: An insulator having an improved fatigue life is disclosed. The insulator comprises a fiber reinforced plastic rod and a holding metal fitting composed wholly or partly of a sleeve, which has a base portion and an inlet portion having a tapered thickness, and holds the rod in the sleeve under pressure.