3-plate mold assembly with a common mold base

A 3-plate mold assembly with a common mold base comprises: a stationary mold mounted on a fixed side of an injection molding machine and a movable mold mounted on a movable side of the injection molding machine. The stationary mold comprises a stationary-side fixed plate on which are disposed four pillars to be inserted through a stripper and into a female insert assembly. When new products need to be produced, it only needs to replace the female and male insert and the rest parts of the stationary and movable molds don't need to be replaced, thus substantially saving production cost.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a plastic injection mold, and more particularly to a 3-plate mold assembly with a common mold base.

2. Description of the Prior Art

Plastic injection molding is used for quick and mass production and has been widely applied in different fields.

A mold is only capable of producing one type of products, so it has to design a whole new mold when a new product needs to be produced. A mold essentially comprises a base and an insert disposed on the base, and then the base is mounted on a plastic injection molding machine. The base and the insert are exclusively designed to pair with each other, therefore, they must be replaced together when a new mold is needed to produce new products, which inevitably creases the production cost. On the other hand, if the products to be produced are large, the corresponding mold must also be relatively large, therefore, the replacing of such a large mold must be inconvenient and probably requires the use of a crane sometimes.

SUMMARY OF THE INVENTION

The primary object of the present invention is to provide a 3-plate mold assembly with a common mold base, when new products need to be produced, it only needs to replace the female and male insert and the rest parts of the stationary and movable molds don't need to be replaced, thus substantially saving production cost.

To achieve the above object, a 3-plate mold assembly with a common mold base in accordance with the present invention comprises: a stationary mold mounted on a fixed side of an injection molding machine and a movable mold mounted on a movable side of the injection molding machine. The stationary mold comprises a stationary-side fixed plate on which being disposed four pillars to be inserted through a stripper and into a female insert assembly.

The movable-side fixed plate is mounted on a movable side of the injection molding machine and comprises a movable-side fixed plate, two space plates, a plurality of clamping blocks and a male insert.

The movable-side fixed plate is mounted on a movable side of the injection molding machine.

The space plates are oppositely disposed on the movable-side fixed plate and each are formed with two holes for insertion of the pillars of the stationary-side fixed plate.

The clamping blocks are L-shaped and each include an assembling portion and a pressing portion, a screw is inserted through the assembling portion and screwed into the space plates, thus fixing the clamping blocks to the space plates.

The male insert is combined with the female insert assembly, in each of two opposite lateral surfaces of the male insert is formed a slide groove, the male insert is positioned between the clamping blocks fixed to the space plates, and the pressing portions of the clamping blocks are engaged in slide groove.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring toFIGS. 1-4, a 3-plate mold assembly with a common mold base in accordance with the present invention comprises a stationary mold and a movable mold. The stationary mold is mounted on a fixed side of an injection molding machine and comprises a stationary-side fixed plate10, a stripper20and a female insert assembly30.

On the stationary-side fixed plate10are disposed four pillars11.

The stripper20comprises a stripping plate21, two racks22, and four pulling rods23. The stripping plate21is formed with four pillar-holes211for insertion of the pillars11of the stationary-side fixed plate10.

The two racks22are disposed at two opposite sides of the stripping plate21.

The pulling rods23are inserted through the stripping plate21and each have one end fixed to the stationary-side fixed plate10.

The female insert assembly30comprises a female insert31, two racks32and a blocking plate33. The female insert31is formed with two holes311, and the two racks32are disposed at two opposite sides of the female insert31and located vertical to the racks22of the strippers20. Each of the racks32is formed with two guiding holes321for insertion of the pillars11. The blocking plate33is abutted against one side of the female insert31and the racks32, and both ends of the racks32are fixed to the racks22. The pulling rods23each have another end fixed to the racks32.

The movable mold comprises: a movable-side fixed plate40, two space plates50, a supporting device60, a plurality of clamping blocks70and a male insert80.

The movable-side fixed plate40is mounted on a movable side of the injection molding machine.

The space plates50are oppositely disposed on the movable-side fixed plate40and each are formed with a plurality of assembling grooves51and two holes52for insertion of the pillars11of the stationary-side fixed plate10.

The supporting device60comprises a first supporting block61and a second supporting block62which are arranged between the space plates50in a superposed manner, and the top surface of the second supporting block62is level with the surfaces of the two space plates50.

The clamping blocks70are approximately L-shaped and each include an assembling portion71and a pressing portion72with an oblique pressing surface721. The assembling portion71is formed to fit in the assembling grooves51of the space plates50, and a screw73is inserted through the assembling portion71and screwed into the space plates50, thus fixing the clamping blocks70to the space plates50.

The male insert80is to be combined with the female insert31and provided with two pins81to be inserted in the holes311of the female insert31, and in each of two opposite lateral surfaces of the male insert80is formed a slide groove82which includes an oblique surface821. The male insert80is positioned in such a manner that each of the slide grooves82is located between the clamping blocks70of the two space plates50, while the oblique pressing surface721is pressed against the oblique surface821of the male insert80.

The structural relations of the respective parts of the 3-plate mold assembly abovementioned are as mentioned above, and the stripper20is used to remove extra materials.

The male insert80is fixed by the clamping blocks70, therefore, the replacing of the male insert80can be easily done by unscrewing the screws73, and then pulling the clamping blocks70out of the assembling grooves51, so that the oblique pressing surface721of the clamping block70is disengaged from the oblique surface821of the male insert80, which allows the male insert80to be pushed out by the user.

Furthermore, since the oblique surfaces821of the male insert80are pressed against by the oblique pressing surface721of the clamping blocks70, when the screws73fix the clamping blocks70to the male insert80, the forces of the screws73will be evenly applied to the oblique surfaces821of the male insert80through the oblique pressing surface721of the clamping blocks70. Furthermore, the force applied to the oblique surface is an oblique force which consists of a vertical component force and a horizontal component force, which provides a much better clamping effect.

Finally, since the female insert assembly30is supported by the racks32and the blocking plate33and assembled to the racks22of the stripper20, it only needs to replace the female insert assembly30when new products are to be produced, and the racks32and the blocking plate33should not be replaced and can still work with the stripper20. That is to say that, when new products need to be produced, it only needs to replace the female and male insert31,80and the rest parts (namely, the mold base) of the stationary and movable molds don't need to be replaced, thus substantially saving production cost.