Abstract: A jig for leak check capable of safely carrying out leak check of a hollow checked object using pressurized gas without damaging it irrespective of its wall thickness. The jig includes a jig body constituted by two joinable members so as to define an inner space therein. In the jig body is provided a closed chamber in which a checked object is hermetically received for leak check. The closed chamber may be formed by the inner space of the jib member itself. Alternatively, it may be formed by cooperation between a depression of a flexible and stretchable air bag arranged in the inner space of the jig body and a part of an inner surface of the jig body. The closed chamber is provided on at least a part of its surface with a leak lead-out element which may comprise a plurality of fine grooves formed in a mesh-like pattern on the surface of the closed chamber or a lining made of an air-permeable material and applied on the inner surface of the closed chamber.

Abstract: A lagged type solenoid capable of carrying out the plunger advancing operation at a speed lower than the plunger retreating operation. For this purpose, the solenoid includes a plunger lagging mechanism, which includes an air discharge passage for discharging air in a plunger moving space to an ambient atmosphere during the plunger advancing operation and an air supply passage for supplying air from the ambient atmosphere to the plunger moving space during the plunger retreating operation which is formed into a sectional area larger than the air discharge passage. The air supply passage is closed by a check valve during the plunger advancing operation. Thus, the plunger advancing operation takes place at a speed lower than the plunger retreating operation.