Die-protecting device used in bending an embossed metallic straight pipe with a small diameter and a thin wall

#1. Field of the Invention

#The present invention is related to a die-protecting device used in bending an embossed metallic straight pipe with a small diameter and a thin wall and having an artistic embossed pattern thereon. The device is comprised of a plastic die core for put in the straight pipe; a pair of half-dies are put on and envelop the straight pipe. A plastic pipe is slipped over the half-dies, then a spiral spring is slipped over the plastic pipe, and further a tension spring is slipped over the spiral spring. Both open ends of the tension spring are provided with a sealing cover. The die-protecting device formed is used for bending the embossed metallic straight pipe with a small diameter and a thin wall and having an artistic embossed pattern thereon. The device has a function of scattering the bending stress on the pipe wall, and thus has a protection effect preventing the pipe wall from collapsing during bending forming.

#2. Description of the Prior Art

#In the drawings:

#FIG. 1 is a perspective view showing the straight embossed pipe is to be bent to form a bent embossed pipe in the present invention;

#FIG. 2 is a perspective view showing mounting of the die-protecting device of the present invention;

#Referring to FIG. 1, the die-protecting device of the present invention is used to successfully bend a straight embossed pipe 1 with a small diameter and a thin wall into a bent embossed pipe 2 having desired curvature. Bending forming of a straight embossed pipe 1 with artistic embossed pattern thereon directly in a bending machine without any die-protecting device will result collapsing and deformation of the pipe wall. Therefore, using of the die-protecting device of he present invention in bending forming of a bent embossed pipe 2 is extremely important and indispensable.

#The die-protecting device of the present invention is comprised of a plastic die core 3, a pair of half-dies 41, 42, a plastic pipe 5, a spiral spring 6, a tension spring 7 and two sealing covers 8 and 80 (as shown in FIG. 2).

#Wherein, he die core 3 is plastic, and is made by placing a plastic bag 31 in a hole 10 of the embossed pipe 1, loading therein with mercury 32 and then sealing the mouth of the bag 31 (as shown in FIG. 2). The mercury 32 with a high specific gravity in the hole 10 squeezes the plastic bag 32 to render the plastic die core 3 adequately full filled in the grains of the inner wall 11 of the pipe hole 10 (as shown in FIG. 3). This helps the wall 11 to bear bending force to get the desired bending curvature. And the bending force can be scattered and almost equally distributed (also referring to FIG. 5) to the whole wall 11.