JPH0628873B2 - Small transfer molding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a compact transfer molding machine.

An example of the transfer molding machine is shown in FIG. Mold 1,
2, a lower heating plate 2, an upper heating plate 5 having a pot 4, and a plunger 6. After inserting the tablet into the pot 4 to preheat it, the plunger 6 is lowered to perform casting. For the operation of the plunger 6, the energy of the spring stored by the hydraulic pressure or the motor is used.

In such a small transfer molding machine, it may be necessary to be portable and to reduce the size and weight depending on the application and place. Hydropneumatic sources may not be available in the field, in which case manual or electrical reliance would be required. In the case of manual operation, there are problems in safety and workability. In the case of electricity, if it is operated directly by a motor,
To protect the motor at the bottom dead center of the plunger, a protective device such as a clutch is required. Moreover, since the position of the bottom dead center differs depending on the variation in the size of the tablet, it is not easy to protect the motor. Therefore, the motor stores energy in the spring, and the energy is used to lower the plunger while controlling the speed with a cam or the like. However, since the motor cannot be arranged on the upper side due to a thermal problem, the mechanism for transmitting the force from the motor to the plunger becomes complicated or large in size, and there is a limit to reduction in size and weight. Also, a large amount of spring deflection is required to insert the tablet, but the pressing force is required at the descending point, but a motor corresponding to the spring force at the ascending point is required, and the casting speed Therefore, it is against the reduction of size and weight.

Therefore, an object of the present invention is to provide an electrically driven compact transfer molding machine which has a simple structure for driving a plunger and which can be made compact and lightweight.

An embodiment of the present invention is shown in FIG. In the figure, 7,
Reference numeral 8 is a pair of molds, and has a cavity 9 and a runner 10. An upper plate 12 and a lower plate 13 having a heater 11 are arranged above and below the molds 7 and 8, and a pot 21 is provided on the upper plate 12. Reference numeral 14 denotes a plunger whose lower end is inserted into the pot 21 and which is supported by a conductive guide member 15 so as to be able to move up and down. The guide member 15 is fixed to a main body frame (not shown). Guide member 15
A ring-shaped conductive terminal 16 is fixed to the plunger 14 below, and a coil spring 17 made of a shape memory alloy is provided by connecting both ends to the guide member 15 and the conductive terminal 16. The spring 17 is loosely fitted around the outer periphery of the plunger 14. The power source 18 is connected to the spring 17 via the guide member 15 and the conductive terminal 16. Reference numeral 19 is a switch. An insulator 20 is provided between the conductive terminal 16 of the plunger 14 and the tip member 14a.

The operation of the above configuration will be described. First, the molds 7 and 8 are set in the molding machine, and the molds 7 and 8 are preheated by the hot plates 12 and 13. The temperatures of the molds 7 and 8 are detected by a temperature set, and when the temperature reaches a predetermined temperature, a tablet (solid) is put in the pot 14. Simultaneously with the preheating of the molds 7 and 8, or after a certain period of time, the switch 19 is closed and a current is also supplied to the spring 17. The energization of the spring 17 causes the spring 17 to generate heat, increase in temperature, and expand. Therefore, the plunger 14 descends and fits between the pots 21 and presses the tablet while melting the tablet.
After a certain period of time, the switch 19 is turned off, the springs of the molds 7 and 8 are released, and the molds 7 and 8 are pulled out horizontally.
As a result, the spring 17 is cooled and contracts, the plunger 14 is pulled up to its original position, and the molding is completed. The molded product is taken out by opening the molds 7 and 8.

In this way, the plunger 14 is driven by the shape memory alloy spring 17. Therefore, the motor is not required, the force transmission mechanism to the plunger 14 is not required, and the speed control cam of the plunger 14 is not required. In addition, the spring 17 made of a shape memory alloy allows a large amount of deflection to improve workability such as insertion of a tablet. For these reasons, the size and weight can be greatly reduced and the device can be made portable.

As described above, the small transfer molding machine of the present invention operates the plunger with a spring made of a shape memory alloy, and heats the spring by energization,
The structure for driving the plunger is simple, the size and weight can be reduced, and the hydraulic and pneumatic pressure sources are not required.

[Brief description of drawings]

FIG. 1 is a cutaway front view of a conventional example, and FIG. 2 is a cutaway front view of an embodiment of the present invention. 7,8 ... Mold, 11 ... Heater, 12 ... Upper heating plate, 1
3 ... Lower heating plate, 15 ... Guide member, 17 ... Spring, 21 ... Pot

Claims (1)

[Claims] 1. A mold, a pot which communicates with a cavity of the mold, a plunger whose front end is freely inserted into and removed from the pot, and one end of which is connected to the plunger and is extended by a temperature rise caused by energization. A compact transfer molding machine comprising a spring made of a shape memory alloy for inserting the tip of the plunger into the pot, and means for energizing the spring.