Abstract: A freezing tank for making ice cream includes an outer tank that has a first enclosing tank wall with a first open end, and an inner tank that is placed in the outer tank through the first open end and that has a second open end surrounded by the first open end. The inner tank has a second enclosing tank wall received in the first enclosing tank wall. The first and second enclosing tank walls confine a cooling chamber for receiving a freezing fluid therein. The second open end is jointed to the first open end in a fluid-tight relationship to prevent leakage of the freezing fluid. Pressurized fluid can enter into the cooling chamber via a first hole that is communicated with the cooling chamber and that allows for insertion of a pressurizing device. A pressure detecting device can be mounted to the first enclosing tank wall to detect a decreased pressure representative of existence of a leakage via a second hole formed in the first enclosing tank wall.

Abstract: A bellows includes a flexible tube with a pleated wall which has valleys and peaks extending in parallel planes across an axis of the flexible tube. At least one of the valleys and at least one of the peaks extend in a respective one of the planes. Each of the valleys and peaks in a corresponding one of the planes is staggered in an axial direction with the other one of the peaks and valleys in an adjacent one of the planes. The pleated wall further has ridges. Each of the ridges is in the form of a segment of a helix and interconnects a corresponding pair of the staggered peaks.

Abstract: A light device includes a housing which has an end with a bulb mounting hole and a conductive plate around the bulb mounting hole, and a light bulb to extend through the bulb mounting hole. The light bulb has a base which includes a cylindrical contact portion and a tip contact portion. The cylindrical contact portion is free of screw threads and has an annular flange. A clamping member clamps the annular flange against the conductive plate so as to establish electrical connection between the light bulb and the conductive plate. The light bulb will not loosen upon impact.