JP2000237825A - Stretch bender with automatic setting machine for tensile force - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep the accuracy of bended shape without adjusting tensile force every time by operators even when variation caused by the strength of a material to be bent is present. SOLUTION: In the initial state where a member to be worked is fixed, the tip of an elongation measuring sensor 13 is in contact with the one end of a guide rod 11. Under this state, when the tensile force of an tension cylinder is increased, the elongation of the member to be worked is increased in accordance with the tensile force, the tension cylinder is moved toward the right by the length of this elongation of the member to be worked and the guide rod 11 which is interlocked with this movement is also moved toward the right, so the tip of the elongation measuring sensor 13 is preessed by the one end of the guide rod 11. At this time, the tip of the elongation measuring sensor 13 is made so as to be retracted inside through a spring and this retraction is measured as the elongation of the member to be worked.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic material such as a metal material for forming an automobile door sash, etc., and to bend a relatively long work material by applying a tensile force in a longitudinal direction. About stretch benders.

[0002]

2. Description of the Related Art The processing material to be bent by a stretch bender varies in the elongation of the processing material due to a difference in a maker, a difference in a manufacturing rod, a difference in a case of passing through a forming roll, etc. even if the material has the same standard. . In addition, even if the shape to be bent is the same, variations occur in products due to differences in the amount of springback after processing. Therefore, when the bending shape or the like of the product changes, the worker finely adjusts the tensile force to maintain the quality of the shape.

[0003]

However, the above-mentioned operation is an operation which can be performed only by a skilled worker to some extent, and requires time for setting pressure.

Further, when a tensile force is applied to a work material and the cross-sectional area is constant in the longitudinal direction, the same stress is generated in any cross section, and even if the magnitude of the tensile force is changed, the work material is changed. Needless to say, it is not possible to increase or decrease the stress of only a certain portion. Therefore, stress concentration occurred at the corners of the curved shape, and the sink of the processed material was increased. Also, abrupt changes in tensile force during bending may cause sink marks or dents in the material to be processed, but depending on the shape of the curved shape, the position of the bending fulcrum of the stretch bender, and the mechanism of the tension device, bending may be performed. In some cases, the tensile force was not constant. In this case, the tensile force had to be increased or decreased according to the information on the bending angle.

In view of the above points, according to the present invention, the tension is automatically set by the elongation of each material even if there is variation due to the strength of the bending material, so that the operator can adjust the tension each time. It is an object of the present invention to provide a stretch bender with an automatic tensile force setting mechanism that can maintain the accuracy of the bending shape without performing the bending.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a stretch bender which fixes both ends of a processing material to a tension chuck, pulls the tension by a tension cylinder, and presses against a mold to perform bending. An elongation measurement sensor for measuring elongation of the elongation, a control circuit for determining measurement data of the elongation measurement sensor, and a hydraulic circuit having a pressure regulating valve operated by a signal from the control circuit, A reference value of the elongation of the processing material calculated from the material and the cross-sectional area of the material is input to the control circuit in advance, and when the measurement data of the elongation measurement sensor reaches the reference value, the control circuit sets the hydraulic pressure to the hydraulic pressure. Sends a signal to the circuit, the hydraulic circuit stops the tension force of the tension cylinder from rising and holds the tension force when the reference value is reached. And gist stretch vendor with automatic setting mechanism of the tensile force and performing bending of the workpiece in a state.

The gist of the present invention is that the tip of the elongation measuring sensor is provided in parallel with the tension cylinder and is in contact with one end of a guide rod that is linked to the movement of the tension cylinder.

The gist of the present invention is that the elongation measurement sensor is fixed to a base slidably attached to a slide shaft of a stretch bender.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. The present invention relates to a tension bender automatic setting mechanism of a stretch bender,
First, a brief description of a stretch bender will be given. FIG. 1 is a front view schematically showing a general stretch bender, and FIG. 2 is a plan view. As shown in FIG. 1, the left and right slide shafts 2 and 2 a of the stretch bender 20 extend from the work table 1 via swing tables 1 a and 1 b that can rotate and swing in the plane direction. A mold base 3 is installed on the upper surface of the mold, and a mold 4 is fixed on the mold base 3. Base columns 5, 5a are attached to the slide shafts 2, 2a via cylinder support members 16, 16a so as to be slidable in the horizontal direction. The tension cylinders 7, 7a attached to the base columns 5, 5a are cylinders. The cylinder support members 6 and 6a are provided so as to be vertically movable and swingable on the cylinder support members 16 and 16a. And tension cylinder 7,
At one end of 7a, tension chucks 8, 8a that hold and fix both ends of the processing member W are installed. Also, a center clamp 9 is attached to the center of the mold base 3,
The workpiece W is fixed such that the center of the workpiece W is sandwiched between the mold 4 and the center clamp 9. The above is the main configuration of the stretch bender 20. After the processing member W is pulled at a constant pressure by the tension cylinders 7, 7a,
Due to the swing and rotation of the swing tables 1a and 1b, the processing member W is pressed against the mold 4 to perform bending.

Next, a method for measuring the elongation of a processed member according to the present invention will be described with reference to FIGS. FIG. 3 is a diagram showing an attachment position of the elongation measurement sensor. As shown in this figure, a chuck rotating device 10 is mounted between the tension cylinder 7a and the tension chuck 8a, and a guide rod 11 extends from the chuck rotating device 10 in parallel with the tension cylinder 7a. One end of the sensor mounting member 12 is fixed to the base 5 a so as to cover the periphery of the guide rod 11. An elongation measurement sensor 13 is fixed to the other end of the sensor mounting member 12.

FIG. 4 is an enlarged view of a stretch measurement sensor portion. In the initial state where the workpiece W is fixed to the tension chucks 8 and 8a, as shown in FIG. 4, one end of the guide rod 11 is in contact with the tip of the elongation measurement sensor 13. In this state, the tension cylinders 7, 7a
When the tensile force of the workpiece is increased, the elongation of the processing member W increases in accordance with the tensile force. Also moves rightward, one end of the guide rod 11 extends and presses the tip of the measurement sensor 13. At this time, the tip of the elongation measurement sensor 13 is retracted inside via a spring, and the amount of the retraction is measured as the elongation of the processed member. As an example of the one used for the elongation measurement sensor 13, model number LGE-1025L manufactured by Mitutoyo can be mentioned. With the accuracy of the elongation measurement sensor 13, elongation in units of 1/1000 millimeter is measured.

FIG. 5 is a diagram showing a procedure for controlling the pressure of the tension cylinder. As shown in FIG. 5, a reference value of elongation calculated from the material of the processed member W and the cross-sectional area per unit length is previously stored in the control circuit 14 by the control panel 14a.
Enter from. The control circuit 14 sends a signal to the hydraulic circuit 15 when the measured value of the elongation sent from the measuring unit 13a of the elongation measurement sensor 13 reaches the input reference value, and sends a signal to the hydraulic circuit 15 to send the hydraulic pressure to the tension cylinder 7a. Is activated, the rise of the tension force of the tension cylinder 7a stops, and the tension force of the tension cylinder 7a holds the value when the elongation of the workpiece W reaches the reference value. It will be. In this state, the workpiece W is pressed against the side surface of the mold 4 by the swing and rotation of the swing tables 1a and 1b described with reference to FIGS.

[0013]

As described above, the present invention relates to a stretch bender which fixes both ends of a processing material to a tension chuck, pulls the tension by a tension cylinder, and presses against a mold to perform bending. An elongation measurement sensor for measuring the elongation of the material, a control circuit for determining the measurement data of the elongation measurement sensor, and a hydraulic circuit having a pressure regulating valve operated by a signal from the control circuit, A reference value of the elongation of the processing material calculated from the material and the cross-sectional area of the processing material is input in advance to the control circuit, and when the measurement data of the elongation measurement sensor reaches the reference value, the control circuit executes A signal is sent to the hydraulic circuit, and the hydraulic circuit stops raising the tension of the tension cylinder and holds the tension when the reference value is reached. Since the gist of the present invention is a stretch bender with an automatic tensile force setting mechanism that performs bending of the above-mentioned processed material in a state, even if there is variation due to the strength of the bent material, the elongation of each material is measured by an elongation measurement sensor. , The tensile force is automatically set by the measurement, so that the precision of the bending shape can be maintained without the operator having to adjust the tensile force each time.

[0014] In addition, since the tip of the elongation measuring sensor is installed in parallel with the tension cylinder and is brought into contact with one end of a guide rod interlocking with the movement of the tension cylinder, the setting of the sensor is set. Therefore, it is not necessary to make special modifications to the stretch bender, and the elongation of the processed material can be measured accurately.

Further, since the stretch measurement sensor is fixed to a base slidably mounted on a slide shaft of the stretch bender, the stretch bender is attached to the stretch bender for fixing the sensor in the same manner as described above. There is no need for special modification, and the elongation of the processed material can be measured accurately.

[Brief description of the drawings]

FIG. 1 is a front view schematically showing a general stretch bender.

FIG. 2 is a plan view schematically showing a general stretch bender.

FIG. 3 is a diagram showing an attachment position of an elongation measurement sensor.

FIG. 4 is an enlarged plan view of an elongation measurement sensor.

FIG. 5 is a diagram showing a procedure of pressure control of a tension cylinder.

[Explanation of symbols]

 Reference Signs List 1 work table 1a, 1b swing table 2, 2a slide shaft 3 mold stand 4 mold 5, 5a base column 6, 6a cylinder 7, 7a tension cylinder 8, 8a tension chuck 9 center clamp 10 chuck rotating device 11 guide rod 12 Sensor mounting member 13 Elongation measurement sensor 13a Measuring unit 14 Control circuit 14a Control panel 15 Hydraulic circuit 16, 16a Cylinder support member 20 Stretch bender

Claims (3)

[Claims] An elongation measuring sensor for measuring the elongation of the processing material in a stretch bender which fixes both ends of the processing material to a tension chuck, pulls the tension with a tension cylinder, and presses the die against a mold to perform bending. And a control circuit for determining the measurement data of the elongation measurement sensor, and a hydraulic circuit having a pressure regulating valve operated by a signal from the control circuit, wherein the hydraulic circuit has a pressure adjustment valve, and is calculated from the material and cross-sectional area of the processing material. The reference value of the elongation of the work material to be processed is input to the control circuit in advance, and when the measurement data of the elongation measurement sensor reaches the reference value, the control circuit sends a signal to the hydraulic circuit, The circuit stops the increase of the tension of the tension cylinder and bends the work material while maintaining the tension when the reference value is reached. A stretch bender with an automatic setting mechanism for tensile force, characterized by processing. 2. The automatic setting of a tensile force according to claim 1, wherein the tip of the elongation measuring sensor is installed in parallel with the tension cylinder and is brought into contact with one end of a guide rod that is linked with the movement of the tension cylinder. Stretch bender with mechanism. 3. The stretch bender with an automatic tensile force setting mechanism according to claim 1, wherein the stretch measuring sensor is fixed to a base slidably attached to a slide shaft of the stretch bender.