JPS6321570B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the roll forming of sheet material, and more particularly to an improvement in the method of roll forming steel sheet into a substantially cylindrical form, such as a pipe.

Roll forming of plate-shaped materials is described in prior patents of the present inventor, such as U.S. Pat.
No.) etc.

The specification of this prior patent describes the roll forming of sheet material, in particular the formation of substantially cylindrical pipes by simply bending the sheet material around a rotatable mandrel. That is, one edge of the steel plate is engaged under the flange of a rib extending axially on the cylindrical surface of the mandrel. The mandrel rotates to advance and bend the steel plate. A complete pipe is formed by bending the steel plate 180 degrees around the mandrel, then engaging the other edge of the steel plate with the mandrel and bending the remaining 180 degrees.

One problem encountered in practicing the invention is maintaining the plates in a mechanically stable relationship on the rotatable mandrel. If proper care is not taken, instability can occur during the final bending phase of the plate during a full 360 degree rotation. This instability is caused by the moments and forces acting on the sheet and tending to cause it to "deviate" from the grippers of the mandrel when it is almost perfectly circular during the final stages of roll forming.

This problem has now been solved by the applicant by the use of friction devices such as stopper devices similar to those described in the prior patents or other braking devices that apply friction to the outer surface of the plate. ing.

According to the inventor's U.S. Pat. No. 3,879,994, in the final stage of rolling, a tapered slipper member with a suitable convex surface is engaged over the roller to bridge the gap between the roller and the sheet material. transfers the load from the rollers to the plate on the mandrel and holds the plate against the mandrel 20, thereby allowing complete forming of the pipe. Although the use of slippers and other external braking devices has proven effective in practice, they are complex and prone to damaging the surface of the workpiece.

According to the invention, one edge of a sheet material is engaged by a gripper device mounted on a cylindrical mandrel provided opposite a pressure device adapted to engage this sheet material. The plate-like material is then moved forward and curved by rotating a mandrel, and the plate-like material is reversed and the opposite edges thereof are engaged to form a cylinder. A method of roll forming a sheet of material to form a cylindrical article, wherein the mandrel and the pressure device are relatively movable so as to control the relationship between the sheet of material and the pressure device. It has been discovered that similar results can be easily achieved by

According to one feature of the invention, a rotatable mandrel having a support for the sheet material and a gripper device for engaging the edges of the sheet material and adjacent to said mandrel and said and a pressure device adapted to engage the plate, the edge of the plate is engaged by the gripper device;
and rotating a mandrel to advance the sheet material through the pressure device to curve the sheet material into a cylindrical shape. and the pressure device is relatively movable and applies force to the advancing plate-like material at least during the final step of roll forming to prevent relative movement between the plate-like material and the mandrel. A method of roll forming the plate-shaped material characterized by the above is provided.

Furthermore, according to the present invention, there is provided a mandrel rotatable above the plate-like material support and a pressure roller device mounted adjacent to the mandrel for contacting and supporting the plate-like material, Carrying out the method, wherein the mandrel and the pressure roller device are relatively movable during at least the final step of a sheet roll forming operation and are adapted to apply a force to the advancing sheet. A device is provided for this purpose.

In this way, contact between the sheet material and the pressure device is maintained at least during the final step of roll forming, thereby creating an additional lateral force on the sheet material. lateral movement of the plate relative to the mandrel and rotation of the plate relative to the mandrel. The lateral forces may or may not include, for example, frictional forces caused by contact between the inner surface of the plate and the mandrel. Preferably, the pressure device is a pair of support rollers mounted below the mandrel on opposite sides of the centerline and movable relative to the mandrel, or the mandrel movable relative to them.

Providing such relative movement, for example, by means of adjustable mechanical linkages or hydraulic cylinders, and omitting additional mechanisms such as slippers or brakes that engage the outer surface of the plate. is simple.

The present invention will be explained in more detail below with reference to the drawings.

First, to explain about FIGS. 1 and 2, these figures show a plate material roll forming apparatus having a horizontal frame 11 equipped with support rollers 12, etc. 13 is adapted to run horizontally on these rollers at an appropriate height. The frame 1 is provided with a cavity 14 in which a heavy I-beam 15 with a horizontal flange extends in a direction perpendicular to the direction of movement of the plate material 13. has been done. The flange 16 on the I-beam 15 has two horizontal rollers 1
7 and 18, and the axes of rollers 17 and 18 are positioned in the longitudinal direction of the I-beam 15 at a suitable height such that the top surface of these rollers is at the same height as the top surface of said roller 12. It is extended along. Therefore, the flat plate-shaped material 13 traveling along the rollers 12 is also traveling while contacting the rollers 17 and 18. The lengths of rollers 17 and 18 are made large enough to engage the entire width of plate material 13. Rollers 17 and 18 are shown supported by end brackets 19 fixed on flange 16, with as many intermediate support brackets as are considered necessary to avoid significant bending. It may also be provided along rollers 17 and 18.

The flange 16 is provided with a device for supporting a mandrel 20 whose axis is I-
Shape - above the web of beam 15 and above roller 1
7 and 18. As shown in FIG. 2, this support device consists of two hydraulic cylinders (power cylinders) 21 and 22. A bearing 23 attached to the upper end of a piston rod 24 of one cylinder 21 is fixed in place. The other cylinder 22 also has a piston rod 25 with a bearing 26 attached to its end, but this cylinder 22 is not fixed to the flange 16 and has a pivot pin 27 attached to a bracket 28 fixed to the flange 16. are connected via. This cylinder 22 is pivotally connected to a piston rod 29 of another hydraulic cylinder 30 which is pivotally connected to the web of the I-beam 15, so that the retraction of the piston rod 29 into the cylinder 30 causes the cylinder 22 to move between its piston rods 25 and 30. Together with the bearing 26, the cylinder 22 can swing downward from the solid line position to the dashed-dotted line position in FIG.

When the cylinder 22 is in its upright position shown by the solid line in FIG.
3 supports the shaft 31 of the mandrel 20. Various mandrels of different diameters can be used by raising and lowering the piston rods 24 and 25 accordingly. Shaft 31 consisting of motor 32 and reduction and reversal gearbox 33
Suitable drives are provided for, both mounted on the I-beam 15 and having a two-headed universal drive coupling member 34 extending from the gearbox 33 to the shaft 31.

The mandrel 20 may be in the form of a cylindrical drum, as shown in FIGS. 1 and 2, with an internal disk or other suitable support member (not shown) provided therein to maintain strength. It is preferable to provide one. However, the mandrel need not necessarily have a completely cylindrical continuous circumferential surface. Furthermore, the power cylinders 21 and 22 can be operated to raise and lower the mandrel during the actual sheet bending operation. This will be explained in more detail below.

One important feature of the mandrel is the provision of a gripper 36 consisting of a continuous axially extending rib on the circumference of the mandrel.
The gripper 36 projects a small radial length from the mandrel and is provided with two circumferentially extending flanges 37, one on each side. These flanges 37 form a gap between themselves and the circumferential surface or partial circumferential surface of the mandrel, the width of which is slightly greater than the thickness of the sheet material with which the mandrel is used.

This gripper 36 on the mandrel 20 exerts a moment equal to the plastic moment of the sheet material 13 against the edge of the sheet material 13 for most of the time when the mandrel 20 rotates in the direction of the arrow in FIG. A vertical force is applied which is equal to the roller action force applied to the sheet material 13 by the rollers 17,18.
3 to 5 schematically illustrate the various steps in forming a pipe according to the invention using the apparatus described in FIGS. 1 and 2. FIG.

The torque applied to the mandrel is practically constant over the entire forming cycle and equal to the plastic moment (MPL) of the plate 13, and this torque is applied to the plate via the gripper 36. Added to the edge of 13. mandrel 20
functions as a guide, and although there is contact between the mandrel 20 and the plate material 13, there is almost no pressure. While the plate 13 is in contact with the mandrel 20, a bending moment equal to the plastic moment (MPL) exists across the plate 13.

In the final step near the completion of the bending shown in FIGS. 4 and 5, unless some kind of prevention device is provided, the moment applied by the gripper 36 causes the plate material 13 to move against the mandrel 20 in the direction of rotation of the mandrel. deviate from or deviate from.

This prevention device is a device that mainly applies a horizontal retraction force or such component force in addition to the roller action force Fr that acts vertically on the plate material 13 up to the final stage.

For example, in the final stage process as shown in FIGS. 4 and 5, MPL (gripper moment) is the moment generated by the externally applied roller acting forces HFr ₁ and HFr ₂ and the internal frictional forces μFr ₁ and μFr ₂ . are opposed by identical and opposite moments consisting of the sum of .

According to the present invention, these moments in opposite directions are caused by the operation of the power cylinders 21, 22 to lower the mandrel 20 in the direction of arrow B (FIG. 4), or by the movement of the two rollers 17, 18 into a plate-like configuration. It is created by raising these rollers by means of a device not shown until they engage the material 13, thereby creating transverse forces Fr ₁ and Fr ₂ . Due to the action of these forces the forces HFr ₁ and
Horizontal components of HFr ₂ are formed, which impart the opposite moments mentioned above. These moments in opposite directions are caused by the curved plate material 13
slipping or dislodging from the mandrel 20.

It has now been discovered that sufficient lateral force to prevent slipping of curved plates can be created without any additional external friction devices as previously used.

[Brief explanation of the drawing]

Fig. 1 is a side view of the main part of the apparatus of the present invention showing the end face of the mandrel, Fig. 2 is an end view of the main part of the apparatus of the invention showing the side face of the mandrel, and Figs. 3 to 5 are roll forming by the method of the invention. 3 is an illustration showing various steps of the method; FIG. 11...Frame base, 13...Plate material, 15...I-
Shape beam, 17, 18... Pressure roller, 20...
Mandrel, 21, 22...Power cylinder, 3
6... Gritspa.

Claims (1)

[Scope of Claims] 1. Gripper means 36 provided on the mandrel so that the front edge of the plate-shaped material is tangential to the mandrel 20 from the front edge of the plate-shaped material 13 in the longitudinal direction.
The mandrel is then rotated so that the plate material is advanced by a pair of rollers 17 and 18 that move the plate material, and the front half of the plate material is curved into a semi-cylindrical shape around the mandrel. Then, the plate is further advanced so as to pass the rear half and the trailing edge of the plate without contacting the mandrel, and then the rear edge of the plate is gripped by the gripper means 36, and the mandrel is gripped. In the method of rotating a mandrel in the opposite direction so as to curve the rear half of the plate-like material into a semi-cylindrical shape around the periphery, thereby joining the front half and the rear half of the plate-like material to form a cylinder, In order to prevent lateral movement between the sheet material 13 and the mandrel ₂₀ , the mandrel ₂
1. A method for roll forming a plate-shaped material, characterized in that the roller is moved relative to the two rollers 17 and 18, and a pressing force due to the relative movement is applied generally in the radial direction with respect to the mandrel. 2. A plate-shaped material support and supply means 12, a mandrel 20 that is arranged above the plate-shaped material support and supply means and bends the plate-shaped material 13 by rotation, a gripper means 36 on the mandrel, and a mandrel 20 that bends the plate-shaped material 13 by rotating the plate-shaped material 13.
In a roll forming apparatus including means for stably engaging the mandrel, the engaging means is provided at the center of the lower part of the mandrel in order to prevent lateral movement or damage to the surface of the plate-shaped plate 13 that is curved by the engagement. It comprises two rollers 17, 18 arranged on opposite sides, and means are provided for making said mandrel 20 and said rollers 17, 18 mutually movable substantially perpendicularly to the surface of said plate-like body 13. A roll forming device for sheet material, characterized in that: 3 The mandrel 20 and the rollers 17, 18
The roll forming of a plate-like material according to claim 2, wherein the means for mutually movable substantially perpendicularly to the surface of the plate-like member 13 is a power device. Device. 4. The roll forming apparatus for plate-like material according to claim 3, wherein the power device is provided to move the mandrel 20 toward the two rollers 17 and 18.