JPS6331929Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a screw dropout prevention device for an in-line screw type injection molding machine.

In-line screw type injection molding machines generally transmit the rotational force of a hydraulic motor or an electric motor to the screw via a key or spline in a bearing section. After injection, the screw is forcibly moved slightly backward (hereinafter referred to as backback) to prevent the resin from flowing out from the nozzle tip, but at this time the screw is prevented from coming off the drive shaft. A conventional screw slippage prevention device is described with reference to FIG. 1. A bearing portion 11 is supported in the radial and thrust directions by a bearing (not shown).
is connected to the rear end of the screw 13 via the left end key or spline 12. Skrillyu 13
A groove 14 is formed in the circumferential direction, and this groove 1
Two screw slip-off prevention plates 15, which are split collars, are fixed to the bearing part 11 by bolts 16, and their tips are inserted into the grooves 14. Therefore, when the screw 13 is moved backward (moves to the right in the figure), the shoulder of the screw 13 comes into contact with the screw slip-off prevention plate 15 to prevent the screw from moving to the right.

This method also prevents the screw from coming off, but when replacing the screw, the screw coming off prevention plate 15
This requires removal, which is time-consuming and reduces productivity, and automation is not possible. A mechanism for automatically removing the screw removal prevention plate 15 has also been proposed, but the structure is quite complicated and the cost is high.

The present invention eliminates these drawbacks, and its purpose is to provide a screw slippage prevention device for an in-line screw type injection molding machine that has a simple structure and can be automated.

The present invention will be explained below with reference to FIGS. 2 and 3 showing one embodiment. A bearing portion 11 supported in the radial and thrust directions by a bearing (not shown) is connected to the rear end of the screw 13 via a key or spline 12 at the left end. A guide plate 21 having a space inside is fixed to the left end of the bearing part 11 in FIG. A screw-off prevention plate 23 is provided. The upper and lower ends of each screw-off prevention plate 23 are in contact with one end of a rod 24 that is inserted into the guide plate 21 and guided in and out, and the other end of the rod 24 has a bolt 25 as shown in FIG.
A pair of arc-shaped leaf springs 26 and 27, which are integrally tightened at both ends, are attached by nuts 28, so that the screw slip-off prevention plate 23 is constantly pressed against the groove 14 of the screw 13 via the rod 24. has been done. Further, a spring 29 is provided between the guide plate 21 and the screw-off prevention plate 23, so that the screw-off prevention plate 23 is always connected to the rod 24.
Although it is being pushed in the direction of opening against the pressing force of
Since the leaf springs 26 and 27 are stronger than the spring 29, the presser plate 23 is normally placed in the groove 14 as shown in FIG.
is in contact with Note that the pin 30 is a guide for the spring 29. Further, as shown in FIG. 3, a hydraulic or pneumatic cylinder 31 is attached to a machine frame (not shown) opposite the joint between the leaf springs 26 and 27.

Next, the operation of the embodiment described above will be explained.
During normal molding, the screw slip-off prevention plate is located at the position shown in FIG.
Because it is in contact with , retreat is prevented. When replacing the screw 13, when the piston of the cylinder 31 is moved forward, the joint between the leaf springs 26 and 27 is pushed in the opposite direction as shown by the arrow a in the figure, and the leaf springs 26 and 27 are compressed and removed from the joint. The rods 24, which are out of phase by 90 degrees, open vertically (in the direction of arrow b). Accordingly, the rod 24 separates from the screw removal prevention plate 23, so that the screw removal prevention plate 23 is opened up and down by the spring 29 and removed from the groove 14 of the screw 13. This makes it possible to replace the screw 13. When the piston of the cylinder 31 is moved back after inserting a new screw, the rod 24 moves inward due to the leaf springs 26 and 27, so the screw slip-out prevention plate 23 is placed inside the groove 14 again. It will enter the state shown in Figure 2.

FIG. 4 shows another embodiment of the present invention, and only the parts different from the first embodiment shown in FIG. 2 will be described. A two-piece screw slippage prevention plate 51 is provided in the groove 14 of the screw 13 and inside the bearing portion 11 and the guide plate 21 . A rod 52 that is guided by the guide plate 21 is fixed to the upper and lower ends of each screw-off prevention plate 51, and a rod 52 that is guided by the rod 52 is installed between the outer periphery of the screw-off prevention plate 51 and the guide plate 21. Because of the spring 53, the screw slip-off prevention plate 51 is pressed against the groove 14 of the screw 13. Here, the outer end of the rod 52 is connected to a piston of a hydraulic or pneumatic cylinder (not shown) or to an electric moving mechanism such as an electromagnet.

Of the operations of this embodiment, exchanging the screw will be explained. Prior to exchanging, the rod 52 is moved outward against the spring 53 by a cylinder or an electromagnet, and then the screw 13 is pulled out and a new screw is inserted.

As mentioned above, the device for preventing the screw coming off of an in-line injection molding machine according to the present invention is installed at the end of the bearing in an in-line screw type injection molding machine in which a groove is provided in the circumferential direction in the screw base, and a space is created inside the screw. a screw slip-off prevention plate that is placed in the space of the guide plate and in the groove of the screw, and that is in contact with the outer periphery of the screw fall-off prevention plate or that is fixed to the outer periphery of the screw fall-off prevention plate. It consists of a rod, a leaf spring or cylinder that controls the movement of the rod, and/or an electric movement mechanism.

For this reason, the screw coming-out prevention device of the present invention uses a cylinder or an electric moving mechanism to open the screw coming-out prevention plate via a rod when replacing the screw, so it can be automated as an injection molding machine without the hassle of conventional methods. became possible. Furthermore, since the structure consists only of a screw slippage prevention plate, a rod, and a mechanism for moving the rod, it has advantages such as low cost.

[Brief explanation of drawings]

Figure 1 is a partially sectional side view of the conventional example;
The figure is a longitudinal cross-sectional view of the present invention, and Figure 3 is 3-3 in Figure 2.
A line sectional view and FIG. 4 are longitudinal sectional views of another embodiment of the present invention. 11... Bearing part, 13... Screw, 14...
Groove, 21... Guide plate, 23, 51... Screw removal prevention plate, 24, 52... Rod.

Claims (1)

[Scope of utility model registration request] In an in-line screw type injection molding machine in which a groove is provided in the circumferential direction in the screw base, a guide plate is attached to the end of the bearing and has a space therein;
A two-part screw fall-off prevention plate placed in the space of the guide and in the groove of the screw, a rod that is in contact with the outer periphery of the screw fall-off prevention plate or fixed to the outer periphery of the screw fall-off prevention plate, and the same rod. A screw slip-off prevention device for an in-line screw type injection molding machine comprising a plate spring or cylinder for controlling the movement of the screw, or an electric movement mechanism.