JPS5914031Y2 - Extrusion pin for core molding - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an extrusion pin for core molding used to release a core from a core mold.

Generally, a pair of core molding dies that are divided vertically or horizontally are used to mold the core.

Then, a core is formed by solidifying the foundry sand between the core molds.

Below, the upper and lower split type will be explained.

In order to take out the core formed in this way from the upper and lower split type core mold, when the upper core mold is separated upward from the lower core mold, the core is removed from the lower core mold. Although it often remains in the mold, it is not uncommon for the core to be lifted upward while attached to the upper core mold.

Therefore, in the past, the upper and lower core molds were each provided with an extrusion pin, and the extrusion pin of one core mold was used to leave the core in the other core mold when the core mold was separated. Currently, the extrusion pin of the other core mold is used to take out the core.

In such a core molding apparatus, it is preferable to omit the ejector pins of one of the core molding molds to reduce the number of ejector pins, thereby reducing the portion of the core that is damaged by the ejector pins.

The object of the present invention is to provide an extrusion pin for core molding that meets such demands.

The present invention provides a locking part that is embedded in the core during core molding to prevent the core from being released in the opening direction, and that is releasable from the core when the core is extruded. By providing the extrusion pin at the tip and giving the extrusion pin a function to pull out the core from the other core mold, the core can be pulled out from one core mold when a pair of core molds are separated. This is characterized in that the extrusion pin of the other core molding die is omitted so that the extrusion pin of the other core molding die is left securely.

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is a lower mold as a core mold, 1a is a recess for core molding in the lower mold, 2 is an upper mold as a core mold,
2a is a recessed portion of the upper die 2 for forming the core.

A through hole 3 is formed in the lower mold 1 and opens into the baseboard forming portion of the bottom surface 1b of the core molding recess 1a.

An extrusion pin 4 is fitted into the through hole 3 so as to be freely protrusive and retractable (that is, vertically movable) toward the opening direction of the core molding recess from the bottom surface 1b.

A flange 5 is integrally provided at the base of the extrusion pin 4, and the flange 5 is rotatably held in a hole 8 formed between an extrusion front plate 6 and an extrusion rear plate 7.

Note that the extrusion front plate 6 and the extrusion rear plate 7 can be moved up and down by a lifting means (not shown).

In addition, the extrusion pin 4 has a locking protrusion at its tip (upper end in the figure) that is embedded in the core 9 and used to pull out the core 9 from the upper mold 2 when the lower mold 1 and the upper mold 2 are separated. 10°10' is provided.

As shown in FIGS. 2 to 4, the locking protrusions 10, 10' are provided point-symmetrically at 180° intervals.

The locking protrusions 10, 10' are inclined in the circumferential direction, as is particularly clear from FIG.

The tips of the locking protrusions 10, 10' are formed at acute angles, and their upper surfaces 10a, 10a' are smoothly inclined toward the base of the other locking protrusion.

The inclination angle θ of the locking protrusions 10, 10' is set to about 45° in FIG. 3.

A cam groove 11 is formed in the intermediate portion of the push-out pin 4, as shown in FIG.

As shown in FIGS. 1 and 5, this cam groove 11 consists of groove portions 11 a and 11 b that are offset by 90° and a groove portion 11 C that connects these groove portions.

A ball holder 12a of the holder 12 faces this cam groove 11, and a ball 1 is disposed between the cam groove 11 and the ball holder 12a.
3 is rotatably held.

The holder 12 is fixed to the lower surface of the lower mold 1 with bolts 14, as shown in FIG.

In other words, these constitute a means for rotating the ejector pin 4, and the ball 13 moves within the cam groove 11 following the upward and downward movement of the ejector pin 4, and as a result, the ejector pin 4 rotates clockwise. Or rotate to the left.

Next, the function of the ejector pin having such a configuration will be explained.

With the locking protrusions 10 and 10' of the push-out pin 4 protruding into the core molding recess 1a as shown in FIG. 1, molding sand is filled between the core molding recesses 1a and 2a, and this casting is The core 9 is formed by hardening the sand with a binder or hardening agent mixed therein.

In this state, the locking protrusions 10 and 10' are embedded in the baseboard of the core 9, so when the upper mold 2 is separated upward from the lower mold 1, the core 9 will move into the locking protrusion. 10, 10' as shown in FIG. 6, and is pulled out from the upper mold 2.

As a result, the core 9 is left in the lower mold 1.

Next, when the extrusion front plate 6 and the extrusion rear plate 7 are raised by a lifting means (not shown), the extrusion pins 4 release the core 9 upward from the lower mold 1.

At this time, the ejecting pin 4 is rotated in the direction in which the locking projections 10, 10' are separated from the core 9 by the action of the cam groove 11 and the ball 13, and when the ball 13 reaches the groove 1a to 1b. Then, the core 9 is released from the locking protrusions 10, 10'.

In the embodiment described above, the extrusion pin 4 is provided on the lower die 1 side, but the extrusion pin 4 may be provided on the upper die 2 side. 10.10' is provided, but the number of locking protrusions may be one or three or more.

Further, although the ejector pin 4 is rotated by the cam groove 11 and the ball 13, the rotation operation of the ejector pin 4 is not necessarily limited to this.

Furthermore, the rotation angle of the extrusion pin 4 at this time is not limited to 90°.

Furthermore, the shape of the locking protrusion provided at the tip of the extrusion pin 4 is as follows:
It is not limited to the shape described above.

Furthermore, the configuration described above may be used in a left-right split type core mold.

As explained above, the present invention has a locking part embedded in the core during core molding to prevent the core from being released in the opening direction and detachable from the core when extruding the core. It is provided at the tip of an extrusion pin provided on one side of the child mold, and this extrusion pin has the function of pulling out the core from the other mold.
When a pair of core molds are separated, the core can be reliably left in one of the core molds.

As a result, the number of ejector pins can be reduced by omitting the ejector pins that were conventionally provided on the other core mold, which has the advantage of reducing the portion of the core that is damaged by the ejector pins.

Moreover, if the locking protrusion is formed in a shape that can be released from the core by rotating the extrusion pin in one direction, the valve can be easily locked and removed from the core with a simple shape. It is also possible to remove the core smoothly without seriously damaging it.

Furthermore, when the extrusion pin is made to protrude and retract from the baseboard forming part of the core toward the opening direction of the core molding recess,
Even if the core is slightly scratched, no scars will remain on the surface of the casting that is cast using it.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of a core forming apparatus showing an embodiment of the present invention. 2 is an enlarged perspective view of the upper end of the ejector pin shown in FIG. 1; FIG. FIG. 3 is a side view of FIG. 2. FIG. 4 is a plan view of FIG. 3. Figure 5 shows ■-v in Figure 1.
Line sectional view. FIG. 6 is a partially enlarged cross-sectional view of the relationship between the extrusion pin and the core shown in FIG. 1 taken from a different angle. 1...Lower mold (core mold), 1b...
Recessed portion for core mold, 1b...Bottom surface, 2...
...Upper mold (core mold), 2a...Recessed portion for core molding, 3...Through hole, 4...Extrusion pin, 9... - Core, 10.10'... Locking protrusion, 11... Cam groove, 12... Holder, 13... Ball.

Claims (2)

[Scope of utility model registration request] (1) It is provided in one of the pair of core molding molds so as to be freely rotatable in and out from the bottom of the core molding recess toward the opening direction thereof, and has a tip that can be joined to the core to be molded. A locking protrusion that can be detached by rotation in one direction is provided, and an autorotation means is provided in the intermediate portion that rotates the locking protrusion in a direction that causes the locking protrusion to detach from the core in accordance with the movement of the locking protrusion in the extrusion direction. An extrusion pin for core molding characterized by the following: (2) Scope of Utility Model Registration Claims In the extrusion pin for core molding as set forth in claim 1, the tip portion is made to protrude and retract from the skirting board forming portion of the core toward the opening direction of the recessed portion for core molding. thing.