Tool for the injection molding of plastics parts

Abstract

A tool for the injection molding of plastics parts has two tool halves that can be moved to and from each other. A mold insert is exchangeably provided in at least one of the tool halves. In addition, a mold core is provided which is inserted in the mold insert and secured by a separate securing element.

Claims

1. A mold for the injection molding of plastics parts, comprising: two mold halves which are movable apart from each other and are movable to each other along a mold axis, a mold insert having at least one mold cavity is arranged exchangeably in at least one mold half, wherein, in the closed state the mold insert and the two mold halves define at least one closed mold cavity for the injection molding of the plastics parts, the mold insert has a plurality of continuous recesses extending there through which extend parallel to the mold axis, and the mold half having the mold insert has a plurality of axially aligned continuing recesses each forming a continuation of a respective one of the recesses in the mold insert, a plurality of exchangeable mold cores are provided, which are insertable parallel to the mold axis into the plurality of recesses of the mold insert, and a single securing element arranged and aligned in each mold half associated with a mold insert, the securing element in the mold half extending transversely to the mold axis and cooperating with the plurality of mold cores to releasably fasten the mold insert to the associated mold half.

2. The mold as claimed in claim 1, wherein the mold core rests on a support surface of the mold half or on a support surface of the mold insert.

3. The mold as claimed in claim 1, wherein the mold core is fixed in a recessed manner with a protruding head within the mold insert and rests on a support surface of the mold half or on a support surface of the mold insert.

4. The mold as claimed in claim 3, wherein the mold core is of T-shaped design.

5. The mold as claimed in claim 1, wherein the mold core projects on a lower end into the continuing recess of the mold half, and in that the securing element is displaceable between first and second positions, wherein the lower end of the mold core is free in the first position, and wherein, after displacement of the securing element into the second position, the lower end of the mold core is secured.

6. The mold as claimed in claim 5, wherein the securing element is formed with a slope on the corresponding side thereof at the lower end of the mold core.

7. The mold as claimed in claim 5, wherein a form-fitting engagement is provided between the lower end of the mold core and the securing element.

8. The mold as claimed in claim 1, wherein a rotary rod which is separate from the mold core is arranged rotatably in the continuing recess, the mold core has an internal thread and an upper end of the rotary rod has an external thread corresponding thereto, and the rotary rod is rotatable in such a manner that, as the external thread thereof is screwed into the internal thread of the mold core, said rotary rod draws said mold core in.

9. The mold as claimed in claim 8, wherein a rack or a friction-locking cable or belt or chain is provided as the securing element for rotating the rotary rod.

10. The mold as claimed in claim 5, wherein, in order to secure the securing element in the second position thereof, a pin which is insertable into the mold half and into the securing element is provided.

Description

(1) Two exemplary embodiments of a mold according to the invention for the injection molding of plastics parts are described below with reference to the drawings. In the latter:

(2) FIG. 1a shows a perspective view of a first embodiment of the mold in the operating position;

(3) FIG. 1b shows a cross section through the mold in FIG. 1a;

(4) FIG. 1c shows a longitudinal section through the mold in FIG. 1a;

(5) FIG. 1d shows a top view of the mold in FIG. 1a;

(6) FIGS. 2a to 2c show corresponding illustrations as in FIGS. 1a to 1c after the pin has been pulled out for release purposes;

(7) FIGS. 3a to 3c show corresponding illustrations as in FIGS. 2a to 2c after the securing element has been displaced for the removal position;

(8) FIGS. 4a to 4c show corresponding illustrations as in FIGS. 3a to 3c after removal of the T-shaped mold cores;

(9) FIG. 5a shows a perspective view of a second embodiment of the mold in the operating position;

(10) FIG. 5b shows a cross section through the mold in FIG. 5a;

(11) FIG. 5c shows a longitudinal section through the mold in FIG. 5a;

(12) FIG. 5d shows a top view of the mold in FIG. 5a;

(13) FIGS. 6a to 6c show corresponding illustrations as in FIGS. 5a to 5c after the pin has been pulled out for release purposes;

(14) FIGS. 7a to 7c show corresponding illustrations as in FIGS. 6a to 6c after the securing element has been displaced for the removal position;

(15) FIGS. 8a to 8c show corresponding illustrations as in FIGS. 7a to 7c after removal of the T-shaped mold cores.

(16) The mold for the injection molding of plastics parts of the first embodiment of FIGS. 1 to 4 has a first mold half 1 and a second mold half (not illustrated).

(17) The mold half 1 has a recess for receiving a mold insert 2. The half cavities for the injection molding of the plastics parts are formed in said mold insert 2.

(18) Screws serve for securing the mold insert 2 in the mold half 1.

(19) The mold insert 2 has two continuous recesses 3. As a continuation of said recesses 3, the body of the mold half 1 has continuing recesses 4.

(20) Furthermore, a slide-like, strip-shaped securing element 5 is arranged in the body of the mold half 1 so as to be displaceable transversely with respect to the recesses 3 or continuing recesses 4. The special characteristic of said slide-like securing element 5 is that the upper side defines a slant.

(21) Furthermore, a separate T-shaped mold core 6 with a head 7 is provided. Said mold core 6 defines a shaping surface on the upper side.

(22) Finally, a pin 8 is also provided, said pin being inserted through a corresponding recess of the mold half 1 outside the mold insert 2 into said mold half 1 and engaging here by means of the front end thereof in a corresponding recess of the securing element 5.

(23) The manner of operation is as follows:

(24) FIGS. 1a to 1d show the locking position of the mold insert 2 in the mold half 1 thereof. This means that the lower ends of the elongate mold cores 6 are in a form-fitting engagement 9 with the securing element 5. As can be seen in particular in FIG. 1b, said form-fitting engagement 9 is formed by intermeshing strips and grooves running in the longitudinal direction of the slant.

(25) According to FIGS. 2a to 2c, in order to release the locking device, the pin 8 is pulled out. The slide-shaped securing element 5 thereby becomes free.

(26) As a result, according to FIGS. 3a to 3c, the slide-shaped securing element 5 can then be pulled out of the mold half 1. The special characteristic here is that, owing to the slant of the securing element 5 or the slant of the form-fitting engagement 9, during the pulling of the securing element 5 out of the mold half 1 the mold cores 6 are moved upward. Right at the end of said displacement movement, the form-fitting engagement 9 between the lower ends of the mold cores 6 and the securing element 5 then comes free.

(27) This means that, according to FIGS. 4a to 4c, the elongate mold cores 6 can be pulled out. As a result, the mold insert 2 becomes free and can be removed from the mold half 1.

(28) A new mold insert 2 is installed in an analogous, reverse sequence.

(29) First of all, the new mold insert 2 is fitted into the associated recess of the mold half 1 (FIGS. 4a to 4c). Subsequently, the T-shaped mold cores 6 are inserted such that they come to lie with the lower ends thereof on the slide-shaped securing element 5 (FIGS. 3a to 3c). The slide-shaped securing element 5 is subsequently moved into the interior of the mold half 1. Owing to the slant of the securing element 5 or of the form-fitting engagement 9 which is then activated, the two mold cores 6 are drawn inward, specifically until the securing element 5 has reached the end position thereof (FIGS. 2a to 2c). Finally, the pin 8 is then also fitted in order to secure the securing element 5 in the mold half 1.

(30) The second embodiment of FIGS. 5 to 8 differs from the first embodiment by means of the securing of the mold core 6 on the mold half 1.

(31) Whereas, in the first embodiment, the mold core 6 is of T-shaped design, in said second embodiment the mold core 6 is of cuboidal design. However, other basic shapes are conceivable.

(32) In any case, the mold core 6 does not have any fixedly arranged rod at the lower end thereof, as is the case in the first embodiment below the head 7 of the mold core 6. Instead, a rotary rod 10 is provided which is arranged rotatably in the mold half 1, but secured in the longitudinal direction. Said rotary rod 10 has an external thread 11 at the upper end. In a manner corresponding thereto, the mold core 6 has an internal thread.

(33) The lower end of the rotary rod 10 has a pinion 12 which meshes with a linearly displaceable rack 13. Instead of the pinion 12 and the rack 13, a friction-locking cable or belt or a chain can also be provided.

(34) The manner of operation is as follows:

(35) FIGS. 5a to 5d again show the locking position of the mold insert 2 in the mold half 1 thereof by means of screws (not illustrated). The rotary rod 10 is screwed by the external thread 11 thereof into the mold core 6 in such a manner that said mold core is drawn downward in the drawing into contact with the mold half 1.

(36) According to FIGS. 6a to 6c, in order to release the locking device, the pin 8 is pulled out. The securing element 5 in the form of the rack 13 thereby becomes free. Also here, as in the first embodiment, the movement of the rack 13 can be carried out by hand, by means of a motor, pneumatically, electrically, hydraulically or in some other manner.

(37) According to FIGS. 7a to 7c, the rack 13 can therefore be pulled out of the mold half 1. As a result, the rotary rod 10 is set into a rotational movement. Since said rotary rod is secured longitudinally, the rotating rotary rod 10 pushes the mold core 6 out because of the thread until the two threads become free from each other.

(38) This means that, according to FIGS. 8a to 8c, the mold cores 6 can be pulled out by hand.

(39) The mold cores 6 are installed in an analogous reverse sequence, i.e. the mold cores 6 are inserted, and then the rotary rod 10 is set into a rotational movement by means of the rack 13 such that the external thread 11 of the rotary rod 10 engages in the internal thread of the mold core 6. Upon further movement of the rack 13, the mold core 6 is drawn into the end position thereof. Finally, the pin 8 is then also fitted in order to secure the rack 13.

(40) In an alternative to the two embodiments, the T-shaped mold core 6 can also be used for securing the mold insert 2 on the mold half 1. For this purpose, the mold insert 2 has a T-shaped recess 3 which corresponds to the T-shaped mold core 6 and has a support surface for the head 7 of the mold core 6, against which support surface the head 7 is pressed during clamping.

LIST OF REFERENCE NUMBERS

(41) 1 Mold half 2 Mold insert 3 Recess 4 Continuing recess 5 Securing element 6 Mold core 7 Head 8 Pin 9 Form-fitting engagement 10 Rotary rod 11 External thread 12 Pinion 13 Rack