A manufacturing method and apparatus for gears for a speed change device. The gears having a large end and a small end forming a reverse-tapered tooth part on an outer circumference thereof, spline teeth of an intermediate material having the small end provided in a rim of the large end thereof, a plurality of dies having a radial shape and an inclination angle to a gear axial line and slidably holding to an inclined axial line on a holding member are slid from outside of the radiation direction toward the center by a pushing cam mechanism, thereby pushing the reverse-tapered blade part formed at the leading end of the die, the spline teeth are formed in the reverse-tapered tooth part, and the die is slid by an extracting mechanism from the center of the radiation direction toward the outside along the inclined axial line.

A roll forming machine for continuously forming a sheet into a joint section of a tube may include a plurality of roller stations arranged longitudinally on a frame and configured to bend the sheet to form the tube, and a carriage slidably secured to the frame. A pleat die assembly may be mounted on the carriage and can be configured to repeatedly engage the tube to form a series of pleats thereby bending the tube to form the joint section. A crimp die assembly may be mounted on the carriage and can be configured to engage the tube to crimp an end of the joint section and sever the end of the joint section from the tube. The carriage may be configured to be selectively moved relative to the frame while the tube is engaged with at least one of the crimp die assembly and the pleat die assembly.

A rebar tying machine may be configured to perform: a winding process in which a wire is fed around rebars, a vicinity of a distal end of the wire is grasped, the wire is pulled back, and the wire is cut; and a twisting process in which the wire is twisted. When instructed to tie the rebars by a user, the rebar tying machine may be configured capable of performing a multiple-winding tying operation in which the twisting process is performed after the winding process has been performed multiple times.

A composite core with non-traditional geometries includes multiple elongate tubes arranged in a two-dimensional array. Each tube is made of a composite material. Each tube includes multiple curved sides. Each curved side inwardly curves toward a longitudinal axis passing through a geometric center of the tube to form a valley on an outer surface of the tube. An end of a first curved side connects to an end of a second curved side to form a crest on the outer surface of the tube. At least one crest formed on an outer surface of a first tube in the two-dimensional array contacts at least one valley formed on an outer surface of an adjacent second tube in the two-dimensional array.

A method includes: an inner pipe insertion step of inserting an inner pipe to between a cored bar and a metal movable claw; a designated section corrugated portion formation step of forming a corrugated portion in a first designated section by pressing the first designated section of the inner pipe radially inward by the metal movable claw and plastically deforming the first designated section; a movable claw moving step of moving the metal movable claw outward in the radial direction of the inner pipe; and an inner pipe moving step of moving a second designated section that is the next designated section to between the cored bar and the metal movable claw.

A joint module for forming a joint section from a tube that is formed at an operational speed by a roll forming machine may include a carriage positioned proximate the back end of the roll forming machine and configured to move in a longitudinal direction relative to the back end. A pleat die assembly may be mounted on the carriage and configured to repeatedly engage the tube to form a series of pleats thereby bending the tube to form the joint section, and a crimp die assembly may be mounted on the carriage and configured to engage the tube to crimp an end of the joint section and to sever the end of the joint section from the tube. The carriage may move relative to the frame while the tube is engaged with at least one of the crimp die assembly and the pleat die assembly.

A roll forming machine for continuously forming a sheet into a joint section of a tube may include a plurality of roller stations arranged longitudinally on a frame and configured to bend the sheet to form the tube, and a carriage slidably secured to the frame. A pleat die assembly may be mounted on the carriage and can be configured to repeatedly engage the tube to form a series of pleats thereby bending the tube to form the joint section. A crimp die assembly may be mounted on the carriage and can be configured to engage the tube to crimp an end of the joint section and sever the end of the joint section from the tube. The carriage may be configured to be selectively moved relative to the frame while the tube is engaged with at least one of the crimp die assembly and the pleat die assembly.

Provided is a flanged member that has a tubular shape and includes a flange portion, the flanged member including: a cross-section changing portion of which a cross-sectional shape changes along an axial direction of the flanged member, in which in any two cross-sections in the cross-section changing portion, a perimeter of one cross-section is 1.25 times or less a perimeter of the other cross-section.

To enhance forming performance enhanced in square tube forming of forming a round tube into a square tube by passing the round tube through a plurality of roll stands arranged in a raw tube forming direction. To give a high degree of multi-usability to a square tube forming device. To suppress the entire length of a roll stand array. A first flat roll stand 20A and a second flat roll stand 20B of rolling directions orthogonal to each other are arranged alternately in a forming direction to form a roll stand array 10. Each of the roll stands 20A and 20B includes roll gap adjusting means by which a rolling amount is independently settable, and one of the first flat roll stand 20A and the second flat roll stand 20B adjacent to each other is driven to rotate by roll driving means 40. A forming rolling amount distribution is allocated individually as a rolling amount at each of the roll stands 20A and 20B. The forming rolling amount distribution is determined in advance for stands from a first-stage stand to a final-stage stand in response to the outer diameter, thickness, and material of a forming target raw tube and an intended dimension of a square tube as a product.

A hot and cold composite formed square and rectangular steel tube and a production method for the same are provided. The radius of an outer corner of the square and rectangular steel tube meets the following conditions: when t is less than or equal to 6 mm, R is greater than 0 and less than 2.0 t; when t is greater than 6 mm and less than or equal to 10 mm, R is greater than 0 and less than 2.5 t; when t is greater than 10 mm, R is greater than 0 and less than 3.0 t, wherein t is the wall thickness of a straight tube part of the square and rectangular steel tube; R is the radius of each of the outer corners of the four corners of the square and rectangular steel tube; and the wall thickness of each corner of the square and rectangular steel tube is between 1.0 t and 1.8 t.