Abstract: A transmission with a simple structure and mechanism, light-weight and compact is realized. In the transmission, a first rotation shaft coaxially fixed to a first turning transmission wheel and a second rotation shaft coaxially fixed to a second turning transmission wheel are arranged in parallel with each other. A support shaft is arranged to extend between the first turning transmission wheel and the second turning transmission wheel. An intermediary transfer wheel is provided on the support shaft rotatably and movably along the longitudinal direction of the support shaft. The intermediary transfer wheel contacts with a side peripheral surface of the first turning transmission wheel and the side peripheral surface of the second turning transmission wheel and moves longitudinally along the support shaft while maintaining the contact.

Abstract: A transmission with a simple structure and mechanism, light-weight and compact is realized. A first rotation shaft 13 coaxially fixed to a first turning transmission wheel 5 and a second rotation shaft 14 coaxially fixed to a second turning transmission wheel 6 are arranged in parallel with each other. A support shaft 17 is arranged to extend between the first turning transmission wheel 13 and the second turning transmission wheel 14. An intermediary transfer wheel 16 is provided on the support shaft rotatably and movably along the longitudinal direction of the support shaft 17. The intermediary transfer wheel 16 contacts with the side peripheral surface 9 of the first turning transmission wheel 5 and the side peripheral surface 10 of the second turning transmission wheel 6 and moves longitudinally along the support shaft 17 while maintaining the contact. The first rotation shaft 13 is rotated by a power device 19 and its rotation can be transmitted with variable speed to the second rotation shaft 14.

Abstract: In a pipe forming process using bending rolls, load applied to an upper roll is reduced to suppress the deflection of the upper roll, thereby suppressing creation of large end gap at the longitudinal center of the pipe, thus enabling production of high-strength, thick-walled elongated pipes. This is achieved either by (1) setting the roll spacing L between lower rolls to a value greater than the sum of the diameter Dwu of the upper roll 34 and the diameter Dwl of each of the lower rolls 32, and setting the amount S of tightening of the upper roll 34 with respect to the lower rolls 32 to a value greater than the radius Rwl of each of the plural rolls; or by (2) effecting pipe forming work on the sheet material such that the spacing L of the lower rolls 32 satisfies the following condition: (Dp+Dwl)>L≧0.

Abstract: In a pipe forming process using bending rolls, load applied to an upper roll is reduced to suppress the deflection of the upper roll, thereby suppressing creation of large end gap at the longitudinal center of the pipe, thus enabling production of high-strength, thick-walled elongated pipes. This is achieved either by (1) setting the roll spacing L between lower rolls to a value greater than the sum of the diameter Dwu of the upper roll 34 and the diameter Dwl of each of the lower rolls 32, and setting the amount S of tightening of the upper roll 34 with respect to the lower rolls 32 to a value greater than the radius Rwl of each of the plural rolls; or by (2) effecting pipe forming work on the sheet material such that the spacing L of the lower rolls 32 satisfies the following condition: (Dp+Dwl)>L≧0.

Abstract: In a pipe forming process using bending rolls, load applied to an upper roll is reduced to suppress the deflection of the upper roll, thereby suppressing creation of large end gap at the longitudinal center of the pipe, thus enabling production of high-strength, thick-walled elongated pipes. This is achieved either by (1) setting the roll spacing L between lower rolls to a value greater than the sum of the diameter Dwu of the upper roll 34 and the diameter Dwl of each of the lower rolls 32, and setting the amount S of tightening of the upper roll 34 with respect to the lower rolls 32 to a value greater than the radius Rwl of each of the plural rolls; or by (2) effecting pipe forming work on the sheet material such that the spacing L of the lower rolls 32 satisfies the following condition: (Dp+Dwl)>L≧0.