Flexible tube for vacuum system

#This invention relates generally to a flexible tube used for a vacuum system, in which vacuum equipment is connected via such a vacuum tube.

#A flexible tube has been used for piping between two or more vacuum devices or equipment. A conventional flexible tube is made of thin sheet metal and is shaped to have an uneven surface with projected parts and depressed or concave parts. If a machine tool or some other hard parts hits the projected parts of a flexible tube, the projected parts of the tube would be deformed and/or broken; and as a result, a vacuum leak might occur. A flexible tube for a vacuum system is usually subjected to a large pressure difference between atmospheric pressure and vacuum pressure. Therefore, such a flexible tube may be deformed or broken due to the pressure difference between the interior and exterior. If a flexible tube is accidentally in contact with an electric wiring, a short circuit might occur and small holes would be formed in the flexible tube.

#Accordingly, an object of the present invention is to provide a flexible tube, which is well protected from pressure difference and mechanical shock. Additional objects, advantages and novel features of the present invention will be set forth in part in the description that follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentality and combinations particularly pointed out in the appended claims.

#FIG. 1 is a schematic diagram illustrating a vacuum system in which a flexible tube according to the present invention is used.

#FIG. 2A is a cross-sectional view showing the structure of a flexible tube according to a first preferred embodiment of the present invention.

#FIG. 2B is an enlarged cross-sectional view showing a part of the flexible tube shown in FIG. 2A.

#In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings which form a part hereto and in which is shown by way of illustration specific preferred embodiments in which the inventions may be practiced. These preferred embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other preferred embodiments may be utilized and that logical, mechanical and electrical changes may be made without departing from the spirit and scope of the present inventions. The following detailed description is, therefore, not to be taken in a limiting sense, and scope of the present inventions is defined only by the appended claims.

#FIG. 1 is a schematic diagram illustrating a vacuum system 12 in which a flexible tube according to the present invention is used. The vacuum system 12 includes a flexible tube 10; a vacuum pump 14 drawing vacuum; and a vacuum chamber 16, in which a vacuum state is to be maintained. The flexible tube 10 is arranged between the vacuum pump 14 and vacuum chamber 16. Both ends of the flexible tube 10 are connected to connecting ports 18 and 20, respectively.

#FIG. 2A is a cross-sectional view showing the structure of the flexible tube 10 according to a first preferred embodiment of the present invention. FIG. 2B is an enlarged cross-sectional view showing a part of the flexible tube 10 shown in FIG. 2A.