Tool for producing fiber-reinforced plastics components in the injection process

Abstract

A tool for producing fiber-reinforced plastics components in the injection process has a receptacle for a plastics component, which receptacle is surrounded by a circumferential seal which is inserted into a groove formed in the tool. It order to devise such a tool with which a higher service life for the seal can be achieved, the invention provides a receptacle chamber as volume compensation.

Claims

1. A tool for producing fiber-reinforced plastic components in an injection process, the tool comprising: a receptacle for a plastics component to be produced; and a circumferential seal surrounding the receptacle, the seal having a circular portion adjoined by a non-circular portion, wherein the seal is inserted into a groove formed in the tool, and a receptacle chamber fluidly coupled with the receptacle is configured to provide volume compensation for injection material injected into the receptacle.

2. The tool according to claim 1, wherein the receptacle chamber is delimited on one side by the tool and on another side by the seal.

3. The tool according to claim 2, wherein the tool comprises an upper tool part and a lower tool part, and the receptacle chamber is delimited by the upper tool part, the lower tool part, and the seal.

4. The tool according to claim 1, wherein the tool comprises an upper tool part and a lower tool part, and the receptacle chamber is delimited by the upper tool part, the lower tool part, and the seal.

5. A tool for producing fiber-reinforced plastic components in an injection process, the tool comprising: a receptacle for a plastics component to be produced; and a circumferential seal surrounding the receptacle, wherein the seal is inserted into a groove formed in the tool, a receptacle chamber fluidly coupled with the receptacle is configured to provide volume compensation for injection material injected into the receptacle, and the receptacle chamber is configured to be curved in a domed manner on a tool side of the receptacle chamber.

6. The tool according to claim 3, wherein the receptacle chamber is configured to be curved in a domed manner on a tool side of the receptacle chamber.

7. The tool according to claim 1, wherein a wall of the seal on a side facing the receptacle chamber is deformable, in a case of an opened tool, the wall is substantially planar, and in a case of a closed tool, the wall is curved in a domed manner toward the receptacle chamber, whereby the receptacle chamber has a substantially lunate or crescent shape.

8. The tool according to claim 6, wherein a wall of the seal on a side facing the receptacle chamber is deformable, in a case of an opened tool, the wall is substantially planar, and in a case of a closed tool, the wall is curved in a domed manner toward the receptacle chamber, whereby the receptacle chamber has a substantially lunate or crescent shape.

9. The tool according to claim 1, further comprising a PTFE coating on a wall of the seal facing the receptacle chamber.

10. The tool according to claim 8, further comprising a PTFE coating on a wall of the seal facing the receptacle chamber.

11. A tool for producing fiber-reinforced plastic components in an injection process, the tool comprising: a receptacle for a plastics component to be produced; and a circumferential seal surrounding the receptacle, wherein the seal is inserted into a groove formed in the tool, and a receptacle chamber is configured to provide volume compensation, wherein a wall of the seal on a side facing the receptacle chamber is deformable, in a case of an opened tool, the wall is substantially planar, and in a case of a closed tool, the wall is curved in a domed manner toward the receptacle chamber, whereby the receptacle chamber has a substantially lunate or crescent shape, and wherein the seal is configured to have: the deformable wall that faces the receptacle chamber, a circular portion, and a portion having two parallel walls, a first of the two parallel walls adjoining one end of the circular portion on one side and transforming into a comparatively long convex portion that terminates at the deformable wall on the other side, a second of the two parallel walls adjoining another end of the circular portion on one side and, on the other side, transforming into a comparatively short portion that extends perpendicularly from the second parallel wall and which is adjoined by a concave region that is opposite the deformable wall, the concave region and the deformable wall being interconnected at ends opposite the circular portion by a region formed of two unequal length portions that are outwardly curved in a domed manner.

12. The tool according to claim 11, wherein the two unequal length portions are themselves interconnected by a relatively short portion that is curved inwardly in a domed manner and that is opposite a center of the circular portion.

13. The tool according to claim 12, wherein on a side opposite the portion having the two parallel walls, the circular portion has a V-shaped clearance, a pointed end of the V-shaped clearance extending beyond a center of the circular portion.

14. The tool according to claim 11, wherein on a side opposite the portion having the two parallel walls, the circular portion has a V-shaped clearance, a pointed end of the V-shaped clearance extending beyond a center of the circular portion.

15. The tool according to claim 1, wherein the seal is made of EPDM or silicone.

16. A tool for producing fiber-reinforced plastic components in an injection process, the tool comprising: a receptacle for a plastics component to be produced; and a circumferential seal surrounding the receptacle, wherein the seal is inserted into a groove formed in the tool, and a receptacle chamber is configured to provide volume compensation, wherein the seal is configured as a round or oval shaped rod, wherein the tool comprises a lower tool part and an upper tool part, wherein the lower tool part has a plunging edge on a side of the seal that faces away from the receptacle, wherein in a case of a closed tool, the plunging edge projects beyond a lower edge of the upper tool part, and wherein the tool further has a chamfer provided at a transition of the lower tool part to the groove.

17. The tool according to claim 16, wherein the rod comprises a core formed of a first material and a surrounding jacket formed of a second material.

18. The tool according to claim 17, wherein the jacket is formed of PTFE or PFA, and the core is formed of an elastomer.

19. The tool according to claim 17, wherein the core has a diameter approximately half that of the rod.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIGS. 1A-1D show a first embodiment of the invention;

(2) FIG. 2 schematically illustrates a seal which is used in the first embodiment;

(3) FIG. 3 schematically illustrates a variant of the seal used in the first embodiment;

(4) FIG. 4 schematically illustrates a second embodiment of the seal; and

(5) FIG. 5 is a sectional view illustrating a lower tool part used in the context of the second seal.

DETAILED DESCRIPTION OF THE DRAWINGS

(6) A first embodiment of the invention is illustrated in FIGS. 1A-1D. The tool for producing fiber-reinforced plastics components in the injection process in the following is shown only in the region which is presently of interest.

(7) The tool has an upper tool part 1 and a lower tool part 2. A receptacle chamber 3, which serves as volume compensation, is delimited by the upper tool part 1, the lower tool part 2 and a seal 4.

(8) The receptacle chamber 3 on the tool side is curved in a domed manner. Furthermore, the seal 4, on the side facing the receptacle chamber 3, has a deformable wall 4a which, in the case of an opened tool, may be substantially planar and, in the case of a closed tool, is curved in a domed manner toward the receptacle chamber 3 such that the receptacle chamber 3 assumes a substantially crescent or lunate shape (cf. FIG. 1B).

(9) A coating of PTFE, or a similar material, is provided on a side of the wall 4a of the seal 4 that faces the receptacle chamber 3.

(10) The seal 4 has a shape which is illustrated in detail in FIG. 2. The seal 4 has a circular portion 4b which is adjoined by a portion having two parallel walls 4c. The portion having the two parallel walls 4c on the one side transforms into a comparatively long convex portion 4d terminating at the wall 4a, and on the other side transforms into a comparatively short portion 4e which perpendicularly extends from the portion having the parallel walls 4c. The portion 4e is adjoined by a concave region 4f which is opposite the wall 4a. The concave region 4f and the wall 4a on the side which is opposite the circular portion 4b are interconnected by a region formed by two portions 4g of unequal length which are outwardly curved in a domed manner.

(11) The two portions 4g, which are outwardly curved in a domed manner are interconnected by a relatively short portion 4h, which is inwardly curved in a domed manner and which is opposite the center of the circular portion 4b.

(12) According to one variant which is illustrated in FIG. 3, the circular portion 4b, on the side which is opposite the portion having the parallel walls 4c, may have a V-shaped clearance 4i which extends beyond the center of the circular portion 4b (cf. FIG. 3).

(13) The seal 4 may be composed of EPDM, silicone, or a similar material.

(14) The functional principle of the design embodiment according to the invention will be explained by way of FIGS. 1A-1D.

(15) The tool is closed in FIG. 1A. During closing, pressure is generated on the portion 4g of the seal, on account of which the wall 4a is deformed in the direction of the tool and, in the closed state of the tool, forms a convex shaping (cf. FIG. 1B). The lunate or crescent-shaped receptacle chamber 3 which serves as volume compensation for the injection material is now configured between the now convex wall 4a of the seal 4, on the one hand, and the upper tool part 1 and the lower tool part 2, on the other hand.

(16) If injection material 5 now makes its way into the receptacle chamber 3, the material 5 is received between the convex wall 4a, the upper tool part 1, and the lower tool part 2, without deforming the seal 4 (cf. FIG. 1C).

(17) Once the tool is opened again after curing in the injection process, the portion 4g, on account of the pressure being released, moves upward again into its initial position. As a consequence, the wall 4a also returns into its initial position and hereby releases itself from the injection material 5, such that the latter may now be readily removed (cf. FIG. 1D).

(18) An alternative embodiment of a seal 6 is illustrated in FIG. 4. This seal 6 is configured as a round or oval rod which has a core 6a from a first material, and a jacket 6b from a second material. The jacket 6b surrounds the core 6a.

(19) The jacket 6b may be composed of PTFE or PFA, for example, and the core 6a may be composed of an elastomer, such as silicone or EPDM. The diameter of the core 6a preferably corresponds to about half the diameter of the rod.

(20) A tool which is used in the context of the seal 6 according to FIG. 4 is illustrated in FIG. 5.

(21) The lower tool part 2 on the side of the seal 6 facing away from the receptacle 7 for the tool has a plunging edge 8 which, in the case of a closed tool, projects beyond the lower edge of the upper tool part 1. A gap 9 is configured between the plunging edge 8 and the upper tool part 1. The plunging edge 8 prevents the seal 6 being sheared away on account of the high pressure during injection. The plunging-edge gap may also be used as volume compensation for the seal 6.

(22) Furthermore, a chamfer 11 for facilitating fitting of the seal 6 is provided at the transition from the lower tool part 2 to the groove 10 which receives the seal 6.

(23) In this embodiment, the receptacle chamber 3 is likewise configured between the upper tool part 1, the lower tool part 2, and the seal 6.

LIST OF REFERENCE SIGNS

(24) 1 Upper tool part 2 Lower tool part 3 Receptacle chamber 4 Seal 4a Deformable wall 4b Circular portion 4c Portion having parallel walls 4d Portion 4e Portion 4f Concave region 4g Portion 4h Portion 4i Clearance 5 Injection material 6a Core 6b Jacket 7 Receptacle 8 Plunging edge 9 Gap 10 Groove 11 Chamfer

(25) The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.