MANDREL FOR BENDING RECTANGULAR DUCT BODY

摘要

A mandrel for bending a rectangular duct body is provided. A round part and a shaft pin hole are formed at the front end of the mandrel, connection pieces and rollers are formed at the front end of the mandrel, protruded parts for supporting the bent part of the rectangular duct body and depressed parts in which depression parts will be formed are formed on both sides of the rollers, and oil grooves are formed in the sides of the rollers. Accordingly, there is an advantage in that workability and productivity can be improved because frictional force between the rollers and between the inside of the rectangular duct body and the rollers is reduced when performing a bending work because grease within the oil grooves formed in the rollers performs a lubrication action.

主权项

1. A mandrel for bending a rectangular duct body in which a screw hole for connecting a rod is formed at a rear end of a rectangular pole, wherein a round part (21) is formed at a front end of the rectangular pole in order to avoid hindrance when the rectangular duct body is bent, wherein a shaft pin hole is formed to penetrate sides of the front end of the rectangular pole, wherein connection pieces are coupled to both sides of the rectangular duct body using a shaft pin (10), and wherein rollers are installed between front ends of the connection pieces using a shaft pin (11),
wherein two of the rollers are installed at parts close to edges of the rectangular duct body on both sides thereof and one of the rollers is closely installed between the two rollers so that the three rollers are individually rotated, wherein when the rollers are subject to a friction action attributable to a bending action within the rectangular duct body, circular oil grooves (2) filled with lubricating oil for reducing friction between the rollers and the rectangular duct body, between the rollers and the connection pieces, between the rollers and the shaft pin (11), and between the rollers are formed in sides of the rollers, and wherein a protruded part (4) is formed at a center of each of the rollers so that depression parts are formed in the rectangular duct body by means of depressed parts (3) when a bending work is performed, and the depressed parts (3) are formed on both sides of the protruded part (4).