WO2012073067A1

WO2012073067A1 - Elastomeric part and method for manufacturing same

Info

Publication number: WO2012073067A1
Application number: PCT/IB2010/003431
Authority: WO
Inventors: Flavio Fantini; Stéphane HARAN; Alain Chahine
Original assignee: Fci Automotive Holding
Priority date: 2010-11-29
Filing date: 2010-11-29
Publication date: 2012-06-07

Abstract

A method for manufacturing a set of elastomeric parts to be mounted on articles, said method comprising the steps of providing a substrate strip (4), at least one moulding cavity (5), and a moulding material (10), and repeating : moving the substrate strip into said cavity while the latter is open, closing the moulding cavity, injecting said moulding material therein, opening the cavity after curing and ejecting the moulded part (3), wherein the moulded part (3) comprises a usable section (1a) adapted to be detached from the substrate strip (4) to be mounted on an article (6), and a support (2) overmoulded on said substrate strip (4) and joined to the usable section (Ia) by a breakable link (7).

Description

ELASTOMERIC PART AND METHOD FOR MANUFACTURING SAME .

FIELD OF THE INVENTION

The present invention relates to elastomeric parts to be mounted on an article, for instance a connector. More particularly, the invention relates to a manufacturing method and an assembly method to manufacture and assemble elastomeric parts, such as elastomeric seals, on articles, such as electrical connectors. Seals and connectors are taken as examples, but of course the invention is not limited to such examples .

BACKGROUND OF THE INVENTION

Elastomeric seals are known in the art, for example from document WO2010032089A1. Usually such elastomeric seals are manufactured by moulding a plurality of them independently and placing them in bulk. Later, thank to a vibrating bowl, the seals are arranged in a row to be prepared to be assembled on an article (an electrical connector in this document) by an insertion machine.

Each time the reference of the seal to be manufactured is changed, the vibrating bowl needs to be adjusted and tuned. However, the vibrating bowl is difficult to adapt to particular geometrical parameters according to the part type to be arranged in a row. This take time during which the machines are not used and consequently it reduces their capacity.

SUMMARY OF THE INVENTION

The present invention proposes a solution to avoid at least part of shortcomings of the prior art.

The invention proposes a method for manufacturing a set of elastomeric parts, said method comprising a first step of providing a substrate strip having a plurality of locations, at least one moulding cavity, and a moulding material. Then, the method comprises a second step of inserting a new location of the substrate strip into said cavity while the latter is open.

A third step consists in closing the moulding cavity, a fourth step consists in injecting said moulding material into the cavity.

A fifth step comprises the transformation of the moulding material into an elastomeric moulded part overmoulded on the strip. A sixth step consists in opening the cavity and ejecting the moulded part overmoulded on the strip.

The method also comprises the repetition of the second to sixth steps.

According to the invention, the moulded part comprises a usable section adapted to be detached from the substrate strip to form, for instance, a desired seal, and a support overmoulded on said substrate strip and joined to the usable section by a breakable link.

According to a further aspect of the invention, the assembly comprising a substrate strip and a plurality of moulded parts may be rolled around a reel.

According to a further aspect of the invention, the above process may be pursued by the following steps :

providing an insertion tool,

then placing a moulded part in front of an article body,

then pushing the moulded part onto the article body with said insertion tool, whereby the usable section is detached from the substrate strip.

The elastomeric part, resulting from the usable section detachment, is assembled, e.g. inserted or mounted, on the article body.

Thanks to these dispositions, elastomeric parts can be manufactured and assembled on articles without using a vibrating bowl. The fact that the parts are oriented when they exit from the mould is used during the process of assembling the parts on the article, rather than placing the elastomeric parts in bulk and then having to go through the hassle of re-orientating them for assembly.

In some other embodiments, one might also use one or more of the features as defined in the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

Other characteristics and advantages of the invention will readily appear from the following description of some of its embodiments, provided as a non-limitative example, and of the accompanying drawings. On the drawings :

Figure 1 is a perspective view of a seal, Figure 2 shows an assembly of seals overmoulded on a substrate strip,

Figure 3 is a partial sectional view of the assembly of Figure 2, with respect to line III of Figure 5,

Figure 4 is a side view of the assembly of Figure 2,

Figure 5 is a top view of the assembly of Figure

2,

Figure 6 illustrates the assembly process with the assembly of Figure 2 and an insertion machine,

- Figure 7a-7c illustrate the insertion process,

Figure 8a-8c illustrate the insertion process according to a variant embodiment, Figure 9 shows a perspective view of the insertion tool, and

Figures 10 and 11 illustrate the moulding process to obtain the assembly of overmoulded parts of Figure 2 rolled on a reel,

Figure 12 shows another embodiment of the invention, and

Figure 13 illustrates a detailed view of the moulding operation.

In the figures, the same references denote identical or similar elements.

Figure 1 shows an elastomeric part, for instance a seal 1, which is adapted to be mounted on an article, for instance an electrical connector. In the illustrated example, the elastomeric seal is a ring seal with a substantially rectangular shape with rounded corners, but other shapes are encompassed within the scope of the present invention.

A manufactured assembly 40 is illustrated on Figure 2. Such assembly comprises a plurality of elastomeric seals 1. More precisely, the assembly 40 comprises a substrate strip 4, or carrier, which is a flat elongated strip having a constant cross-section. At predetermined locations along the substrate strip 4 there is a plurality of overmoulded parts 3, which are made of a cured elastomeric material.

Each overmoulded part 3 comprises :

a support 2 which is overmoulded on the substrate strip 4, and

- a seal section la which is attached to the support 2 by a breakable link 7.

The seal section la is adapted to be detached from the substrate strip and in particular from the support 2 to result in a desired elastomeric seal 1 as depicted in Figure 1.

The substrate strip 4 extends along a longitudinal axis X along a longitudinal distance which can be rather important whereby the substrate strip 4 may comprise a large number of locations, at least one hundred locations, each of said location bearing one overmoulded part 3.

A transversal axis Y extends perpendicularly to the longitudinal axis X, the substrate strip 4 has a strip width Wl along said transversal axis Y. A vertical axis Z extends perpendicularly to said longitudinal and transversal axis X,Y. The thickness Tl of the substrate strip 4 along the vertical axis Z is small, preferably between 0.2 mm and 1.5 mm, so that the substrate strip 4 exhibits a good flexibility according to the vertical axis Z. The strip 4 may be for example a flat metallic strip .

Referring now to Figures 2, 3, 4 and 5, the overmoulded part 3 has a length L, a width W2 and a height HI, and comprises the support 2 overmoulded on the substrate strip 4. The support 2 has a thickness T2 which is for example comprised between twice and four times the thickness Tl of the substrate strip 4.

Advantageously according to the invention, the seal width W2 along the transversal axis Y is at least four times larger than the substrate strip 4 width Wl, and therefore the size of the substrate strip 4 can be much smaller than the size of the seals. Further a given type of substrate strip can be used to manufacture different types of seals, with various dimensions. In the example illustrated (cf. Fig. l-8c) , the elastomeric seal 1 comprises an alternate series of protrusions 58 and grooves, a top face 57 opposed to the support 2. The support 2 of the overmoulded part 3 comprises two overmoulded areas 9 which are substantially diametrically opposed and located at the intersection of the substrate strip and the support 2. The seal section is attached to the support by the already mentioned breakable link 7 which is, in the depicted example, discontinuous and comprises a plurality of linkage portions 7a, at least two linkage portions 7a; in particular, there is no linkage portion 7a in the overmoulded portion 9. As seen from Figures 7b and 8b, the linkage portions 7a (dotted line) are distributed and balanced on the periphery of the seal section la except in overmoulded portions 9.

The overmoulded parts 3 are spaced from each other along the longitudinal axis X by a distance D, which is also the interval distance separating the already mentioned locations on the substrate strip 4.

According to another aspect of the invention, the assembly 40 is rolled on a first reel 11 (see Fig. 6) thanks to the flexibility of the substrate strip 4. The elastomeric moulded parts 3 overmoulded on the substrate strip are also flexible so that this assembly can be easily rolled on the first reel 11 (also visible on Figure 11).

According to another aspect of the invention, and in relation with Figures 6, 7a-7c and 8a-8c, the process of inserting elastomeric seals 1 on articles, here connectors 6, will be described in details. The assembly 40 is pulled from the first reel 11 along the longitudinal axis X and faces an insertion machine 80 having an insertion tool 8 which can be moved perpendicularly to the X axis and parallel to the Z axis according to the arrow 81.

The insertion tool has a shape especially adapted to the insertion method step: in particular the front border 83 (Fig. 9) has a substantially rectangular form corresponding to the shape of the seal 1, and this front edge 83 is interrupted by two recesses 85 provided to let the passage for the substrate strip 4. Each recess 85 has a side wall 84 and a bottom wall 86, and the width of the recess is slightly larger than the width Wl of the substrate strip 4.

When one overmoulded part 3 is located on the axis Zl of the connector 6, the insertion tool 8 is moved toward the connector 6 parallel to the connector axis Zl. As a result, the first the seal section la is inserted around a first connector section 6a comprising electrical contacts. As the seal is an elastomeric part, no particularly precise locating is required.

When the insertion tool 8 moves further toward the connector 6, the support 2 arrives in the immediate vicinity of the front face 6c of the first connector section 6a, which is illustrated in Fig 7a and Fig 8a.

The last part of the displacement of the insertion tool 8 results in breaking the breakable link 7 as it will be explained below respectively for the first and second variant embodiments.

Regarding the first variant embodiment (Fig. 7a-7c) , the support 2 is located radially outwardly relative to the seal section la.

During the last part of the displacement of the insertion tool 8, the substrate strip 4 abuts against the front face 6c of the first connector section 6a and the support 2 is retained by the substrate strip 4 thanks to the overmoulded portions 9. The extra displacement of the insertion tool 8 (see Fig 7c) breaks the linkage portions 7a .

Regarding the second variant embodiment (Fig. 8a- 8c) , the support 2 is located radially inwardly relative to the seal section la.

During the last part of the displacement of the insertion tool 8, the support 2 abuts against the front face 6c of the first connector section 6a, and the support 2 is retained in this place while the insertion tool 8 tears apart by shearing the breakable link 7,7b on the external edge 6d of the front face 6c. Advantageously in the second variant embodiment, the ring seal section has an inward surface circumscribed around a inner cylindrical surface 90, and the support has an outward exterior surface defining an exterior cylindrical surface 91. Said exterior cylindrical surface has a smaller dimension and can be fitted into said inner cylindrical surface 90 of the ring seal, thereby enabling an easy shearing by the insertion tool 8.

Finally, for both variant embodiments, after the linkage portions 7a, 7b have been broken, the separated seal 1 is pushed on the connector body against the second body section 6b.

Returning to figure 6, it will be understood that the method includes the repetition of placing a new article (e.g. a connector) in front of the insertion tool 8, moving the assembly (substrate and seals) by translating the substrate strip 4 along the X axis by the distance D separating the overmoulded parts 3, and then proceeding with the insertion process described here above .

Furthermore, a support removing machine 20 can be placed downstream the insertion place, this support removing machine 20 having a cutting object 20a adapted to tear apart the remaining support 2 and to remove it from the substrate strip, so the substrate strip 4 is freed from remaining material and can be reeled on a second reel 12. Further, the substrate strip 4 can be recycled and reused to manufacture again an assembly 40 comprising a substrate strip 4 and a plurality of moulded parts 3.

Figure 10 illustrates schematically the moulding process used to form a moulded part 3, thanks to a cavity 5 which has a shape designed to manufacture such moulded parts 3. A moulding material 10, for example a silicon based material is injected via a sprue channel into the cavity while the latter is closed. A catalyst or a catalytic material can be added to the silicon based material .

After transforming, for example curing, at ambient temperature or medium temperature, the mould 16 is opened, and the moulded part 3 is ejected from the cavity 5.

Figure 11 illustrates the process of moulding several moulded parts 3 simultaneously, for instance five in the depicted example. The substrate strip 1 is coming out of a third reel 13, which can be in the case of recyclability identical to the second reel 12 already mentioned, and pulled into a cavity arrangement 55 comprising individual cavities 5. Then the molding process takes place for each cavity 5 as explained above. The molding process results then in five new moulded parts 3 placed at locations spaced by the distance D already mentioned. The substrate strip 4 together with the moulded parts 3 form the assembly 40 which is rolled onto the first reel 11, ready to be used by the insertion machine .

Figure 12 shows another embodiment of the invention, in which the substrate strip 4 comprises a plurality (five in the example given here) of primary strips 14a to 14e extending parallel to one another and spaced apart by a distance which is slightly below the width W2 of the overmoulded part 3 to be moulded. Thanks to this disposition, the cavities 55 of a mold 16,17 can be located astride two neighbouring primary strips 14a-14e. In the example shown, four cavities extend astride five primary strips 14a-14e in a row along the transversal axis Y.

The primary strips 14a-14e, can be linked to one another by spacer members 15, which maintain a constant distance between two neighbouring primary strips.

Figure 13 shows in a more detailed manner the mold 16 comprising a first plate 21, a second plate 22, and a third plate 23. The first plate includes the sprue channel 10, and a base portion 55a of the cavity.

The second plate is interposed between the first and third plates 21,23 and comprises a second portion 55b of the cavity. The third plate 23 comprises the core portion 55c defining the cavity.

Further, a longitudinal space for the strip 4 or primary strips 14a-14e is arranged between the first and second plates 21,22. After closing the mold 16, an elastomeric material is injected through the sprue channel 10. After curing, the first operation to release the overmoulded part 3 is the displacement of the third plate 23 according to the arrow 43. Once the third plate 23 is at location 23', the core portion 55c is not anymore engaged in the overmoulded part 3. Thanks to its elasticity, the overmoulded part 3 is deformed during the second operation consisting in moving downwards the second plate 22 (according to the arrow 42) .

After, the first plate 21 is moved upwards according to arrow 41 releasing the moulding assembly comprising the substrate strip and the overmoulded part 3.

This assembly is then shifted horizontally to be moved out of the mold, and a new portion of the substrate strip 4 is ready in front of the mold 16 plates to enable a new moulding operation.

It is to be noted that within the scope of the present invention, the substrate strip 4 can be of different types, other than metallic, for example plastic materials like polycarbonates, poly-ethylens

( terephthalate or naphtalate) , poly-imides. The substrate strip could also be made of fabric materials like aramid based tissues, or even paper based material.

Claims

1. A method for manufacturing a set of elastomeric parts to be mounted on articles,

said method comprising the steps of:

a- providing a substrate strip (4) having a plurality of locations, at least one moulding cavity (5) , and a moulding material (10),

repeating :

b- inserting a new location of the substrate strip into said cavity while the latter is open,

c- closing the moulding cavity,

d- injecting the moulding material (10) into the cavity e- transforming the moulding material to result in at least an elastomeric moulded part (3) overmoulded on the strip,

f- opening the cavity and ejecting the moulded part (3) overmoulded on the strip,

wherein the moulded part (3) comprises a usable section (la) adapted to be detached from the substrate strip (4) to form a desired part (1), and a support (2) overmoulded on said substrate strip (4) and joined to the usable section (la) by a breakable link (7) .

2. A method according to claim 1, wherein the part (1) is an elastomeric ring part, and wherein the support (2) is overmoulded on said substrate strip (4) at two overmoulded portions (9) which are substantially diametrically opposed along a longitudinal direction (X) .

3. A method according to any of the preceding claims, wherein the substrate strip (4) extends along a longitudinal axis (X), has a strip width (Wl) along a transversal axis (Y) which is perpendicular to the longitudinal axis (X) , wherein the part has a part width (W2) along the transversal axis (Y) which is at least four times larger than the strip width.

4. A method according to claim 1, wherein the substrate strip (4) comprises a plurality of primary strips (14a-14e) extending parallel to one another, wherein the part (1) is an elastomeric ring part, and wherein the support (2) is overmoulded on said substrate strip (4) at two overmoulded portions (9) which are substantially diametrically opposed along a transversal direction (Y) , the two overmoulded portions (9) being located respectively on two neighbouring primary strips.

5. A method according to any of the preceding claims, wherein the substrate strip is a flat metallic strip .

6. A method according to any of the preceding claims, wherein the moulding material (10) is a silicon material .

7. A method according to any of the claims 2-6, wherein the breakable link attaches the usable section to the support (2) by at least two linkage portions (7a) spaced away from overmoulded portions (9) and wherein where the usable section (la) is separated from the support (2) within said overmoulded portions.

8. A method according to claim 7, wherein the breakable link (7) comprises a plurality of linkage portions (7a) spaced away from one another and balanced on the periphery of the ring seal except in overmoulded portions ( 9) .

9. A method according to any of the preceding claims, further comprising the additional step of rolling on a first reel (11) the assembly (40) of the substrate strip (4) with the elastomeric moulded parts (3) overmoulded on the substrate strip.

10. A method according to any of the claims 2-9, wherein the usable ring section has an inward surface circumscribed around a inner cylindrical surface (90), wherein the support has an outward exterior surface defining an exterior cylindrical surface (91), wherein said exterior cylindrical surface can be fitted into said inner cylindrical surface (90) of the usable ring section .

11. A method for manufacturing a set of assemblies of an elastomeric seal (1) and an article, comprising the steps defined in claim 1 and further comprising the steps of :

h- providing an insertion tool (8)

i- placing the moulded part (3) in front of a article body ( 6) ,

j- pushing the moulded part (3) onto the article body (6) with said insertion tool,

whereby the usable section (la) is detached from the support (2) and the substrate strip (4) .

12. A method for manufacturing a set of assemblies of an elastomeric part (1) and an article according to claim 9 and claim 11, comprising further the steps of: g- supplying the moulded parts (3) from the first reel (11) .

13. A method according to claim 12, further comprising the step of

h- removing the support (2) from the substrate strip,

k- rolling the substrate strip (4) on a second reel

(12), whereby the substrate strip (4) can be re-used.

14. An assembly (40) comprising a substrate strip (4) and a plurality of moulded parts (3),

each moulded part (3) comprising a usable section (la) adapted to be detached from the assembly to form a desired part (1), and a support (2) overmoulded on said substrate strip (4) and joined to the usable ring section (la) by a breakable link (7) .

15. An assembly according to claim 14, wherein the breakable link (7) attaches the usable portion (la) to the support (2) in at least two portions spaced away from an intersection portion (9) where the support is overmoulded on the substrate strip.

16. An assembly according to claim 14, wherein the substrate strip (4) comprises a plurality of primary strips (14a-14e) extending parallel to one another.

17. An assembly according to claim 16, wherein the support (2) is overmoulded on said substrate strip (4) at two overmoulded portions (9) which are substantially diametrically opposed along a transversal direction (Y) , the two overmoulded portions (9) being located respectively on two neighbouring primary strips.