JPS6112093Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a safety hook device for preventing mold clamping in a molding machine.

In a molding machine such as a die casting machine or an injection molding machine, a mold clamping cylinder performs mold clamping and mold opening via a toggle mechanism or the like. When the mold is opened, a part of the worker's body is inserted between the molds to clean the mold.

If a part of the worker's body is placed between the fixed mold and the movable mold, and an unexpected accident such as breakage of the piston rod of the mold clamping cylinder or electrical failure occurs, the movable mold will move forward, causing a major accident to the workers. Furthermore, if there is a possibility that such an accident may occur, workers cannot always work with peace of mind.

FIGS. 1 and 2 explain a conventional device. In the molding machine, which is generally designated by the reference numeral 1 in the figures, a fixed mold 4 is mounted on a fixed platen 2 and a movable platen 3, respectively.
A movable mold 5 is attached.

On the movable platen 3 side, there is a toggle mechanism 6 which is a booster.
is provided. This toggle mechanism 6 has toggle links 7 and 8, both of which are rotatably connected via a pin 9. One toggle link 7 is rotatably connected to the link housing 10 via a pin 11. The other toggle link 8 is rotatably connected to the movable platen 3 via a pin 12.

A mold clamping cylinder 13 is provided on the outer surface of the link housing 10, and its piston rod 1
The tip of the piston rod 14 faces the link mechanism 6 side, and the guide rod 1 is located at the tip of the piston rod 14.
A crosshead 15 guided by 7 is fixed. The crosshead 15 and the link 7 are rotatably connected by a link 16. Therefore, when the mold clamping cylinder 13 acts and the piston rod 14 extends, the crosshead 15 moves forward and the links 7 and 8 become straightened, and a large force acts on the movable platen 3 due to the lever principle, and the fixed metal Type 4
The movable mold 5 is brought into a clamped state, and injection molding is performed.

Conversely, when the piston rod 14 moves back, the links 7 and 8 are folded, the crosshead 15 also moves back, and the movable platen 3 moves back together with the movable mold 5, opening the mold.

The crosshead 15 for moving the movable platen 3 is the second
As shown on an enlarged scale in the figure, it is arranged so as to be slidably fitted into two guide rods 17 arranged in the same horizontal plane, and linear guidance is performed. The tip of the guide rod 17 is fixed to the movable platen 3, and the other end, ie, the rear, passes through the link housing 10 and is slidably supported by the end platen 10.

In the conventional device, as shown in Fig. 2,
A cylinder 18 is attached to the rear surface of the link housing 10, and a hook 19 is fixed to the tip of the piston rod of the cylinder 18. A notched groove 20 is formed on the side surface of the guide rod 17 at a position facing the hook 19 at the retracting limit of the movable platen 3. Then, at the backward limit of the movable platen 3 when opening the mold, the cylinder 18 is activated and the hook 19 is fitted into the notch groove 20, thereby locking the guide rod 17 and preventing the movable platen 3 from moving forward in the event of an unexpected accident. is prevented.

However, if the notch groove 20 is provided in the middle of the guide rod 17 in this way, stress concentration will occur in the notch groove 20 portion, and there is a risk that the guide rod 17 will be cut off from this portion. Guide rod 17 has
Due to unbalanced loads due to machining accuracy errors and lubrication differences in each part of the toggle mechanism, a bending moment is applied, and sometimes several tons of bending stress or tensile stress may be applied, resulting in deflection on the order of millimeters. . In particular, a large force acts on the guide rod 17 during mold clamping. Furthermore, if a burr is formed in one place between the molds when the molds are clamped, the parallelism of the movable mold to the fixed mold may be on the order of millimeters per meter. Also at this time, a large force acts on the guide rod 17.

Therefore, from the viewpoint of the strength and life of the guide rod 17, it is not preferable to provide the notched groove 20 in the guide rod 17, which is subjected to a considerably large force.

If the diameter of the guide rod 17 is increased in an attempt to overcome these drawbacks, breakage can be prevented to some extent, but the device becomes larger and heavier, which is also economically disadvantageous.

In addition, since the toggle mechanism is an excellent force booster, when the links 7 and 8 are in the straightened state during mold clamping, a force 20 to 25 times the output of the mold clamping cylinder 13 is applied to the guide rod 17 and the movable platen 3. . Even at the start of mold clamping, a force several times the output of the mold clamping cylinder 13 is applied. Therefore, it is not preferable to operate the safety hook in the cutout groove 20 in the middle of the guide rod 17.

Furthermore, lubricant is supplied to the inner surfaces of the link housing 10 and the crosshead 15 on which the guide rod 17 slides, and the link housing 10
The front and rear surfaces of the crosshead 15 are sealed in contact with the outer peripheral surface of the guide rod 17 to prevent lubricant from leaking.
If the cutout groove 20 is provided in the middle of the guide rod 17, when the cutout groove 20 of the guide rod 17 moves in and out from inside the crosshead 15 or link housing 10, a part of these sliding surfaces will directly communicate with the outside.
As a result, lubricant leaks to the outside, requiring an unreasonably large amount of lubricant and soiling the machine.

The purpose of this invention is to
To provide a safety hook device for preventing mold clamping of a molding machine, which is configured to reliably prevent mold clamping with an extremely simple structure.

Hereinafter, the present invention will be explained in detail based on embodiments shown in the drawings.

FIG. 3 illustrates one embodiment of the present invention.
In the figure, the same parts as in FIGS. 1 and 2 are designated by the same reference numerals, and the explanation thereof will be omitted.

In this embodiment, a cylinder 21 is provided on the side surface of the link housing 10, and is arranged so that its piston rod 21a can move forward and backward in a direction orthogonal to the guide rod 17. A hook 22 is fixed to the tip of the piston rod 21a. The mounting position of the hook 22 is set so that it is located in front of the crosshead 15 when the movable platen 3 and the crosshead 15 reach the retracting limit during mold opening.

In this embodiment, since the structure is as described above, the mold clamping cylinder 13 is operated to move the piston rod 14 backward, and the crosshead 15 and movable platen 3 are moved back.
When the cylinder 21 is operated when the cylinder 21 is positioned at the rearward limit, the piston rod 21a moves forward and the hook 22 faces the front surface of the crosshead 15. Therefore, even if the piston rod 14 moves forward and the movable platen 3 etc. try to move forward due to some kind of accident, the crosshead 15 will be prevented from moving forward by the hook 22, and the toggle mechanism 6 will not be in the straightened state. , accidents caused by accidental mold clamping can be reliably prevented. Of course, there is no need to provide a groove in the guide rod, on which a considerable force is applied, and the safety hook can be actuated with a relatively small force. The forward and backward limits of the hook 22 are detected by a limit switch (not shown), and a predetermined signal can be sent.

As is clear from the above explanation, according to the present invention, a cylinder serving as a drive device for the safety hook is provided on the link housing side, the hook is fixed to the tip of the piston rod, and the crosshead at the retraction limit is locked by this hook. Therefore, it is possible to obtain a safety hook device that can reliably prevent unexpected mold clamping accidents with an extremely simple structure. Further, since there is no need to provide a cutout groove for a safety hook on the guide rod, no inconvenience occurs.

[Brief explanation of the drawing]

1 and 2 are a front view showing a conventional structure and a plan view (partial sectional view) in an open state of the mold, and FIG. 3 is a plan view (partial sectional view) showing an embodiment of the present invention. . 1...Molding machine, 2...Fixed plate, 3...Movable plate,
4... Fixed mold, 5... Movable mold, 6... Toggle mechanism, 7, 8, 16... Toggle link, 10
...Link housing, 13...Mold clamping cylinder,
15...Crosshead, 17...Guide rod,
21...Cylinder, 22...Hook.

Claims (1)

[Scope of utility model registration request] A crosshead is attached to the mold clamping cylinder of a molding machine that clamps the mold using a toggle mechanism, and a safety hook drive device is attached to the link housing at a position corresponding to the front position of the crosshead at the mold opening limit, and a safety hook drive device is attached to the front side of the crosshead when the mold is opened. A safety hook device for preventing mold clamping for a molding machine, characterized in that a hook is provided on the link housing side so that the hook can move forward and backward, and the movable platen is prevented from moving forward due to the action of the hook and crosshead.