JPH04332631A - Device for correcting dimensions of box-like molded article - Google Patents

Abstract

PURPOSE:To provide a dimension correcting device, with which the after-mold dimensions of a box-like molded article can easily be corrected. CONSTITUTION:The dimensional correcting device concerned consists of a correcting device main body 2, arms 3-6, each of which is mounted advanceably to and retractably from the correcting device main body, a servo motor 11, which drives the arms so as to advance and retract, and pressing plates 7-10, which are jointed to the tips of the arms 3-6. By driving the servo motor 11, the arms 3-6 are advanced to and retracted from the device main body 2, resulting in adjusting the positions of the pressing plates.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dimension correction device suitable for correcting the dimensions of a box molded product or the like after molding in injection molding, compression molding, or the like.

0002

[Prior Art] Normally, when a square box is molded by injection molding, the inside corner of the molded product inside the mold cools later than the outside, so if the molded product is taken out of the mold and then left to cool, the Inward warping as shown in 8 occurs in the side plate, resulting in dimensional defects. For this reason, conventional attempts have been made to reduce the defects as much as possible by changing molding conditions such as mold temperature, injection speed, pressure, etc. However, there are cases in which defects cannot be reduced even if the various conditions are adjusted. In this case, inward warping has been prevented by fitting a wooden frame 50 shown in FIG. 9 onto the molded product immediately after molding, inflating each side plate of the molded product outward with the wooden frame, and leaving it to cool.

0003

[Problem to be Solved by the Invention] However, in this method using a wooden frame, the size of the wooden frame for expanding each side plate of the molded product outward is determined by trial and error, so a number of wooden frames of different sizes are used. It had to be manufactured and took a lot of time. Furthermore, since the inside dimensions of the molded product immediately after molding are smaller than the wooden frame, it is difficult to fit the wooden frame into the box, and although inward warping can be prevented, on the contrary, the wooden frame sometimes causes problems such as outward warping.

That is, the conventional method of using a wooden frame to correct the dimensions of a box molded product after molding has the following problems. b) It takes too much time to determine the appropriate size of the wooden frame. b) The inside dimensions of the molded product are smaller than the wooden frame, making it difficult to fit the wooden frame into it. C) Even if it is possible to prevent the box from warping inward, the wooden frame may still cause it to warp outward.

Therefore, in order to solve the above-mentioned problems, the present invention provides a pressing plate for each side plate of the box molded product, which is completely different from the conventional wooden frame, inside the box molded product immediately after molding. It is an object of the present invention to provide a dimension correction device having an operating mechanism for pushing out to an arbitrary position, and to solve the above-mentioned conventional problems.

[0006]

[Means for Solving the Problems] Therefore, the present invention provides a pressing plate that can face the inner surface of each side plate of a box molded product immediately after molding, and an operating mechanism that pushes the pressing plate to an arbitrary position. It consists of the following, and is used as a means to solve problems.

[0007]

[Operation] A dimension correction device is installed inside the box molded product immediately after molding, and a pressing plate is pushed out to an arbitrary position against each side plate of the box molded product to correct the dimensions of the side plates. It is also possible to readjust the dimensions by freely changing the position of the pressing plate within the subsequent straightening time. Generally, a resin product immediately after molding is still at a high temperature (approximately 100° C.) inside the wall of the molded product, so the molded product contracts when left to cool to room temperature. However, when this device is used, the pressing plate prevents the side plates of the box from being displaced, thereby preventing inward warping (inward warping). In addition, the amount of extrusion of the side plate of the box by the pressing plate can be freely varied and tested using this device, and the warping of the side plate after being left to cool can be optimized so as to be minimized. Furthermore, after pushing the side plates of the box to a certain position with the pusher plate, the pusher plate can be gradually pulled back depending on the state of cooling. Warping) can be prevented.

[0008]

[Embodiments] The present invention will be described below with reference to the drawings. Fig. 1 is a perspective view of a dimension correction device according to an embodiment of the present invention, and Fig. 2 is a perspective view of an arm insertion/extraction adjustment section inside the device. FIG. 3 is a sectional view taken from N to N in FIG. 1.

In FIG. 1, reference numeral 1 indicates a box molded product taken out from a mold, and a dimension correction device according to the present invention is disposed inside this box. This dimension correction device includes a correction device main body 2, arms 3 to 6 attached to the correction device main body 2 so as to be freely removable and removable, a servo motor 11 for driving the arms 3 to 6 in and out, and ends of the arms 3 to 6. It is composed of pressing plates 7 to 10 coupled to the parts, and a spring 12 that acts to draw the arms 3 to 6 into the correction apparatus main body 2. Further, when the servo motor 11 is driven, the arms 3 to 6 are moved in and out of the device main body 2, thereby adjusting the position of the pressing plate.

Next, referring to FIG. 2, the parts for adjusting the insertion and removal of the arms 3 to 6 will be explained. 13 is a cross guide having a tapered portion at the end, and 14 is a screw, and this screw 14 is connected to a servo motor. . Further, arms 3 to 6 each having a tapered portion are arranged opposite to the end of the cross guide 13, and the arms 3 to 6 are pushed toward the tapered portion of the cross guide 13 by a spring 12 shown in FIG. energized. Therefore, when the servo motor rotates, the screw 14 rotates, and the rotation of the screw 14 causes the cross guide 13 to move up and down as shown in FIG. The vertical movement of the cross guide 13 is converted into horizontal movement of the arms 3 to 6 via the tapered portion.

The detailed configuration of the adjustment section will be further explained with reference to FIG. 3. FIG. 3 is a sectional view taken along the line N--N in FIG. 1, and the output shaft 12 of the servo motor 11 is directly connected to the screw 14. The arms 3 to 6 are arranged in the main body of the device so that they can be slid horizontally and the cross guide 13 can be slid vertically. Each arm is pushed out by pushing down the cross guide 13 by rotating the servo motor 11. , by moving the arms outward against the force of the spring 12. Further, by arbitrarily stopping the rotation of the servo motor 11, the pressing plates 7 to 10 connected to each arm can be stopped at an arbitrary pushing position. On the other hand, each arm is pulled back by rotating the servo motor in the opposite direction, pulling up the cross guide, and moving the arms inward by the force of the spring 12.

FIG. 5 is a plan view of an embodiment of the present invention.
This figure shows a state in which the dimensions of the box molded product 1 are being corrected immediately after molding. First, put the device in a box with the arms 3 to 6 retracted, then push out each arm and attach each pressing plate 7 to
Push out each side plate of the box with step 10. Immediately after molding, the inside of the molded product is still at high temperature, and each side plate of the box tries to displace inward due to contraction when left to cool to room temperature, but the extruded pressing plate prevents this displacement. This prevents the side plates from warping inward. In addition, the amount Y of extrusion of each pressing plate is defined as the amount by which the side plate of the box protrudes outward based on the straight virtual position as shown in the figure.

FIGS. 6 and 7 show the relationship between the extrusion amount Y and the straightening time. In both figures, Y0 indicates the initial extrusion amount when the arm is first extruded and the side plate of the box is pushed out with the pressing plate, and the straightening time is started from there. In FIG. 6, the initial extrusion amount Y0 is maintained during the straightening time, which is similar to the conventional straightening using a wooden frame. However, since the initial extrusion amount Y0 can be freely changed by changing the extrusion position of the arm, it is possible to find the extrusion amount that minimizes the warpage of the box molded product. Next, Fig. 7 shows a method to deal with the case where the initial extrusion amount Y0 is kept at the same value as shown in Fig. 6, causing it to warp outward.By gradually decreasing the extrusion amount from the initial Y0, the Make sure that no warpage remains.

FIG. 4 shows another embodiment of the present invention, in which a cylinder 21 is used in place of the servo motor 11 in the previous embodiment. In FIG. 4, 24 is a nut that fixes the screw 22 at the tip of the rod of the cylinder to the cross guide 13. By moving the cross guide up and down using a cylinder, the pressing plate can be taken in and out. Note that the driving source for the cylinder may be electricity, hydraulic pressure, pneumatic pressure, or any other source.

[0015]

[Effects of the Invention] As explained in detail above, the present invention provides the following excellent effects. That is, since the position at which each side plate of the box molded product is pushed apart by the pressing plate can be set arbitrarily, the position at which the side plate is pushed apart (the amount of extrusion) where the warpage of the side plate is minimized can be easily found, and With the pressing plate pulled back, the present straightening device can be installed inside the box molded product without any problem. In addition, by gradually pulling back the pressing plates that are initially pushed apart as the straightening time elapses for each side plate of the box molded product, it is possible to prevent the pressing plates from warping outward. Therefore, according to the present invention, the dimensions of a box molded product can be easily and efficiently corrected after molding.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a dimension correction device according to an embodiment of the present invention.

FIG. 2 is a perspective view of an arm insertion/extraction adjustment section inside the device.

FIG. 3 is a sectional view taken from N to N in FIG. 1;

FIG. 4 is a sectional view of another embodiment in which a cylinder is used as a drive device instead of the servo motor in FIG. 3;

FIG. 5 is a plan view of a state in which dimension correction is performed according to an embodiment of the present invention.

FIG. 6 is a graph when the amount of extrusion of the side plate of the box is held constant.

FIG. 7 is a graph when the amount of extrusion of the side plate of the box changes over time.

FIG. 8 is a perspective view of the box molded product in an inwardly warped state.

FIG. 9 is a perspective view of dimensional correction using a conventional wooden frame.

[Explanation of symbols]

1 Box molded product 2　Orthodontic device body 3-6 Arm 7-10 Pressing plate 11 Servo motor 12 Spring 13 Cross guide 21 Cylinder

Claims (1)

[Claims] [Claim 1] Box molding characterized by comprising a pressing plate that can face the inner surface of each side plate of a box molded product immediately after molding, and an operating mechanism that pushes the pressing plate to an arbitrary position. Product dimension correction device.