Device for demoulding negatives in thermoplastic injection moulds

Abstract

The device for demoulding negatives in thermoplastic injection moulds comprises an ejector (1) provided on one of the ends thereof with a figure insert (2) with a profile complementary to the part that is to be moulded, wherein said ejector (1) comprises an outer tube (11) housing an inner cooling tube (12), which cools said figure insert (2). It allows for a device to be provided for demoulding negatives in thermoplastic injection moulds which enables the part to be obtained to be cooled, the cooling circuit reaching the figure area of the mould.

Claims

1. A device for demoulding negatives in thermoplastic injection moulds comprises an ejector provided on one of the ends thereof with a figure insert with a profile complementary to a part that is to be moulded, characterised in that said ejector comprises an outer tube housing an inner cooling tube, which cools said figure insert, wherein said outer tube is made of a flexible material.

2. The device for demoulding negatives in thermoplastic injection moulds according to claim 1, wherein the outer tube is made of carbon fibre, carbon fibre mixed with fibreglass, or graphene.

3. The device for demoulding negatives in thermoplastic injection moulds according to claim 1, wherein said figure insert is joined to the ejector by means of a joining head.

4. The device for demoulding negatives in thermoplastic injection moulds according to claim 3, wherein the joining head comprises at least one airtight seal.

5. The device for demoulding negatives in thermoplastic injection moulds according to claim 1, wherein the inner cooling tube is made of stainless steel.

6. The device for demoulding negatives in thermoplastic injection moulds according to claim 1, wherein said ejector defines an upper segment and a lower segment, the longitudinal axis of the upper segment forming an acute angle (A) with the longitudinal axis of the lower segment.

7. The device for demoulding negatives in thermoplastic injection moulds according to claim 6, wherein said acute angle (A) formed by the longitudinal axis of the upper segment with the longitudinal axis of the lower segment is less than or equal to 6°.

8. The device for demoulding negatives in thermoplastic injection moulds according to claim 1, which also comprises a guide bushing (7) on the inside of which said ejector (1) moves.

9. The device for demoulding negatives in thermoplastic injection moulds according to claim 1, wherein the ejector is fastened to an ejector plate by means of a fastening base, a tightening cone and a tightening nut.

10. The device for demoulding negatives in thermoplastic injection moulds according to claim 1, wherein said ejector comprises on the far end thereof of the figure insert a cooling source provided with an inlet for cooling liquid and an outlet for cooling liquid, the inlet of the cooling liquid being produced through said inner tube and the outlet of the cooling liquid being produced through a space defined between the outer tube and the inner tube.

11. The device for demoulding negatives in thermoplastic injection moulds according to claim 1, wherein the outer tube is made of carbon fibre, carbon fibre mixed with fibreglass, or graphene.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) To better understand what has been set forth, several drawings are attached in which a practical embodiment is schematically depicted merely by way of non-limiting example.

(2) FIG. 1 is a cross-sectional elevation view of the device for demoulding negatives in thermoplastic injection moulds according to the present invention.

DESCRIPTION OF A PREFERRED EMBODIMENT

(3) First of all, it must be indicated that the device according to the present invention is used to demould negatives that are usually considered small, meaning, with dimensions smaller than 3 mm, in the negative area thereof.

(4) As shown in FIG. 1, the device for demoulding negatives in thermoplastic injection moulds comprises an ejector 1 provided on one of the ends thereof with a figure insert 2 with a profile complementary to the part that is to be moulded.

(5) According to the present invention, said ejector 1 comprises an outer tube 11 which houses an inner cooling tube 12, which cools said figure insert 2.

(6) Said outer tube 11 is made of a flexible material, for example, carbon fibre, carbon fibre mixed with fibreglass, or graphene, or any other suitable material.

(7) Furthermore, said ejector 1 defines an upper segment 13 and a lower segment 14, the longitudinal axis of the upper segment 13 forming an acute angle (A) with the longitudinal axis of the lower segment 14, this angle being less than or equal to 6°.

(8) As shown in FIG. 1, said lower segment 14 is placed substantially straight and said upper segment 13 is slightly inclined, up to a maximum of 6°, as indicated previously.

(9) On one of the ends of the ejector 1 are joined, preferably by means of a high-resistance bicomponent glue, a connection bushing called a joining head 3, which carries two mechanised grooves, in order to house the O-ring seals 4, 5 therein, an upper one and a lower one, which will be necessary to meet two necessary requirements.

(10) The upper seal 4 has the objective of ensuring the airtightness of the cooling of the figure insert 2, which each mould setter will manufacture, while the lower seal 5 will act to guarantee the airtightness of the device in the moulds incorporating the vacuum in the injection process.

(11) This joining head 3 further incorporates a housing 6 for a quick-change system, in order to ensure the connection and position of each figure insert 2.

(12) For the fastening of the device to the punch plate 8 of the mould in the corresponding position, a threaded bushing is used called a guide bushing 7, with the required demoulding inclination (maximum of 6° of inclination), the drilling of which in its entirety must cross through all the plate 8.

(13) This bushing 7 will be the guide through which the outer tube 11 will slide in the demoulding movement thereof and will be positioned beneath the housing of the figure insert 2.

(14) For the final assembly of the device in the mould, first, the outer tube 11 must slide through the guide bushing 7 inserted in the punch plate 8, with the insert 2 for the fastening thereof in the ejector plates 9, by means of a bushing duly housed between the same ejector plates 9 called the fastening base 10, by means of a tightening cone 14, and a tightening nut 15, fastening the device with precision.

(15) Then, the outer tube 11 is cut, underneath the ejector plates 9, the final length of which has to allow us to couple a cooling source 16, provided with a cooling inlet 17 and a cooling outlet 18.

(16) Since the thickness of the ejector plates 9 is variable, depending on the dimensions of the mould, each mould setter will determine the exact position for fastening the cooling source 16.

(17) The cooling source 16 incorporates an airtight seal 19 on the inside thereof, which has the objective of preventing coolant leaks, as well as said inner tube 12 duly fastened thereto, which will need to be cut in the length thereof up to the insert 2.

(18) Through this inner tube 12, the cooling liquid will enter in order to generate the cooling of the figure insert 2, and the evacuation of this cooling liquid will be performed through the space between the very outer tube 11 and the inner tube 12.

(19) The cooling source 16, therefore, is fastened to the lower end of the outer tube 11, by means of a thread created for this purpose. As the cooling source 16 already incorporates an airtight seal 19, which enables the inlet and outlet directions to be positioned in the suitable direction for each need.

(20) The total length, both that of the outer tube 11 and of the inner tube 12, will need to be cut, therefore, according to each application.

(21) It should be taken into account that between the ejector plates and the base plate of the mould, enough space must be arranged in order to house all the tubes which will feed the cooling circuits, duly connected to the cooling source 16.

(22) Despite having referred to a specific embodiment of the invention, it is evident for one skilled in the art that the device that has been described is susceptible to a number of variations and modifications, and that all the mentioned details can be replaced with other technically equivalent ones without departing from the scope of protection defined by the attached the claims.