JPH0621694Y2 - Injection mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a synthetic resin injection mold.

<Prior Art> As shown in FIG. 2, an injection molding die having a hot runner structure is composed of a fixed die 1 and a movable die for forming a gap 3 for molding a product corresponding to the fixed die 1. Become, fixed type 1
Has the hot runner structure.

In this hot runner structure, a block 5 having a resin storage chamber 4 for storing a resin injected from an injection device (not shown) and evenly distributing the resin to the plurality of nozzles 6, and the plurality of nozzles 6 are provided. A heater 7 is attached to the fixed die 1, a heater 7 is attached to the block 5, and a heater 8 is attached to the nozzle 6 so that the resin is heated to a predetermined temperature.

<Problems to be Solved by the Invention> In the above hot runner structure, the block 5 and the nozzle 6 are displaced due to thermal expansion due to high temperature heating by the heaters 7 and 8. Therefore, as shown in FIG. ,
Hemispherical connecting portions 9, 10, 11 are formed at a plurality of locations. Since the connecting portions 9, 10 and 11 simply press-bond to absorb the thermal expansion, resin leakage occurs from the connecting portions 9, 10 and 11 if the preheating is insufficient or the resin pressure is erroneously set.
It becomes a failure such as disconnection.

In order to detect this resin leakage, a heat-resistant micro switch 12, which is swingably held by a thin plate on the connecting portions 9, 10, 11
If 13 and 14 are arranged and resin leaks, the fixed switch 1 is pressed by pushing the microswitches 12, 13 and 14 by the leaked resin.
Wiring the detection signal of the switch by abutting against the wall surface of the
It is taken out via 15 and sent to the molding machine control panel to give an alarm and stop molding.

However, in the case of a plurality of nozzles, the connecting portions 9, 10,
There are a large number of 11 parts, and if other parts where resin leakage is predicted are included, there are 20 or more parts. If all the microswitches are arranged in these parts, a large number of microswitches are required, and there is no space for installing the microswitches in some parts, which makes the wiring and the like complicated. In addition, once the resin leaks, the resin will be welded to the microswitch and wiring and cannot be reused, and it will be necessary to replace it with a new microswitch and wiring, which is time-consuming and costly. Further, since the micro switch is attached by a thin plate so as to be swingable, there is a problem that a malfunction occurs due to vibration or the like.

<Means for Solving the Problems> The present invention has been made in order to solve the above-mentioned conventional problems, and is characterized by a hot runner block having a resin reservoir and a hot runner block Fixed mold with a hot runner nozzle inside which resin is distributed from the resin reservoir of the runner block and injected into the product molding gap,
In an injection molding die consisting of a movable die corresponding to this fixed die, the fixed die is provided with an air intake port and a smoke collection discharge port sandwiching the hot runner block and the hot runner nozzle, and the smoke collection discharge port The smoke sensor is arranged to send to the molding machine control panel.

<Operation> With the above configuration, when the resin leaks from any part of the hot runner structure, the resin component evaporates due to the high temperature to generate smoke, which is intensively detected by the smoke sensor to generate an alarm and It stops the molding machine.

<Embodiment> An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is a fixed die, 2 is a movable die, and 3 is a gap for molding a product. A block 5 having a resin reservoir chamber 4 in the fixed mold 1 as in the conventional case, a nozzle 6 in which resin is distributed from the resin reservoir chamber 4, heaters 7, 8 (for heating the block 5 and the nozzle 6). (Not shown in FIG. 1) and a hot runner structure.

The present invention comprises the fixed die 1 and the block 5 and nozzle 6
An air intake 20 and a smoke outlet 22 are provided, a smoke collecting slope 21 is formed in the vicinity of the smoke outlet 22, and a smoke sensor 23 is provided at the smoke outlet 22. Is. The smoke sensor 23 sends a detection signal to a molding machine control panel (not shown) via a signal converter 24 as needed. still,
If the smoke sensor 23 itself has a signal conversion function, the signal converter 24 is not required separately.

Since the present invention has the structure as described above, when resin leaks in the fixed mold 1, smoke is generated due to high temperature, and this smoke is generated by the air flow entering from the air intake port 20 and the inclined surface for smoke collection.
Smoke is collected at 21 and is positively guided to the smoke outlet 22, and smoke is reliably detected by the smoke sensor 23. The signal detected by this smoke sensor 23 is transmitted to the molding machine control panel to give an alarm. Along with this, the molding machine is stopped.

<Effect of the Invention> As described above, according to the present invention, since the smoke sensor intensively detects resin leaks in a large number of portions where resin leaks are expected to occur in the fixed mold, a large number of micro-sensors are required as in the conventional case. The need for switches and wiring is eliminated, there is no restriction on the mounting of microswitches and wiring, and it is not necessary to replace parts each time resin leakage occurs, resulting in cost reduction.

Furthermore, smoke generated by resin leakage is forcibly guided to the smoke outlet by the air flow from the air intake, so it can be reliably detected, and there is no failure or malfunction due to vibration. There is.

[Brief description of drawings]

FIG. 1 is a sectional view of the present invention, FIG. 2 is a sectional view of a conventional mold, and FIG. 3 is a sectional view showing a resin leak detection structure in the conventional mold. 1 ... Fixed type, 2 ... Movable type, 4 ... Resin storage chamber, 5 ... Block, 6 ... Nozzle, 7, 8 ... Heater, 20 ... Air inlet, 21
… Smoke collecting slope, 22… Smoke outlet, 23… Smoke sensor.

Claims (1)

[Scope of utility model registration request] 1. A fixed mold having a hot runner block having a resin reservoir chamber and a hot runner nozzle for distributing the resin from the resin reservoir chamber of the hot runner block and injecting the resin into a product molding gap, and the fixed mold. In an injection molding die consisting of a movable mold corresponding to the above, the fixed mold is provided with an air intake and a smoke collecting and discharging port by sandwiching the hot runner block and the hot runner nozzle, and the smoke collecting and discharging port controls the molding machine. An injection mold that has a smoke sensor that sends it to the board.