GB2281530A

GB2281530A - Improvements in the procedure and mould for manufacturing grommet elements

Info

Publication number: GB2281530A
Application number: GB9415366A
Authority: GB
Inventors: Teixido Miquel Jorda
Original assignee: Lear Automotive EEDS Spain SL
Current assignee: Lear Automotive EEDS Spain SL
Priority date: 1993-08-03
Filing date: 1994-07-29
Publication date: 1995-03-08
Anticipated expiration: 2014-07-29
Also published as: ES2076866A1; PT101430A; ES2076866B1; PT101430B; DE4343656A1; FR2708799A1; FR2708799B1; GB9415366D0; GB2281530B

Description

1.

--- -1- IMPROVEMENTS IN THE PROCEDURE AND 2281530 FOR MANUFACTURING GROMMET ELEK The present application f or a Patent of Invention, as indicated in its wording, concerns "IMPROVEMENTS IN THE PROCEDURE AND MOULD FOR MANUFACTURING GROMMET ELEMENTS", the new construction, conformation and design features of which fulfil the aim for which they have been specifically designed, with maximum safety and efficiency.

There are some grommet elements that exist on the market and can, therefore, be considered as the state of the art, whose function is that of permitting the passing of a set- of wires (more than 20) from the engine compartment of an automobile to its passenger area, or between any other two compartments, so that once the element is attached to the hole in the metal plate through which the wiring has passed, total insulation from water, gases and noise is achieved.

The present invention provides a procedure adapting the element in two successive operations over the actual wiring, the first consisting in insulating the wire bundle under pressure, and the second, in surface-moulding the PVC or other thermoplastic elastomer to give shape to the grommet, using three different plastic products.

In function of the dif f erent designs of the grommet elements and according to the recommended procedure, once completed, the following functions may be fulfilled:

lst - Insulation of the bundle from water, gases and noise.

2nd - Insulation of the bundle with respect to the grommet.

3rd - Insulation of the entire wire bundle-grommet unit from water, gases and noise.

4th - Construction of a clamp-plate to allow for attachment to the metal plate and rigidity of the unit.

Sth - Construction of a barrier seal for the grommet and partition plate.

6th - Construction of some legs for preliminary attachment to the metal plate, to facilitate the tightening of the screws.

7th - Use of self -threading screws, which is possible because of the plastic clamp.

8th - Housing of the screws, which allows them to be used without a joint.

9th Acoustic insulation.

10th Assembly from the interior or exterior, thanks to a casing disc which covers the through hole.

llth - Attachment holes, the quantity and distribution of which depends on the thickness of the metal plate and their locatlon.

The cycle of the recommended procedure comprises, at minimum, some of the following operations:

a) Assembly of the wiring with the terminals connected.

b) Shaping of the bundle and taping of two adjacent points an the bundle of wire formed.

c) Insertion of the bundle in the lower part of the mould.

d) Closing of the mould.

e) Approximation of the two adjacent points of the bundle by mechanical -pneumatic or hydraulic means, to produce the bulge in the wires that make up the bundle.

f) Application of the glue inside the mould under pressure, at a high temperature and for a set amount of time.

g) Injection of the glue at a high temperature in between the wires.

h) Refrigeration of the mould to allow the glue to - 30 solidify.

i) Surf ace moulding of the PVC or other thermoplastic elastomer to give shape to the grommet element as necessary, connecting the insulated bundle to the clamp or plate.

There are no antecedents of this type of procedure, although some related procedures are described in German Patent no. 4017077, belonging to" Robert BoschGmbH (however, in this Patent, the surface moulding operation is carried out over a specific part and for a small quantity of wires); other related procedures are described in European Patent no. 179,657, belonging to Raychem GmbH, and in French Patent No. 8509989, belonging to the firm Lisa Draxlmeier.

In a second aspect, the present invention provides a mould for manufacturing grommet elements wherein the mould, according to the procedure, is formed by a semimould that includes a left-hand and a right-hand closure support, which support wire closures, and a semi-mould formed by some wire closures which are supported by a closure support.

Other details and features of the present application f or a Patent of Invention will become clear during the description which follows, wherein reference is made to the drawiilgs that accompany this specification, which provides, in a somewhat schematic manner, the preferred details. These details are given by way of example, referring to a possible embodiment, but this is not limited to the details which are hereinafter set forth, and therefore this description should be seen as designed to illustrate and without any kind of limitation.

The varibus elements numbered in the drawings attached to the current specif ication are set forth as follows: (10) mould, (10s) upper semimould, (10i) lower semimould, (11s) upper left-hand stationary wire closure support, (11i) lower left-hand stationary wire closure support, (12s) upper right-hand mobile wire closure support, (12i) lower right-hand mobile wire closure support, (13d) lower right-hand stationary wire closure, (13i) lower left-hand stationary wire closure, (14d) upper right-hand wire closure, (14i) upper left-hand wire closure, (15) entrance for glue at a high temperature, (16) duct, (17) moulding chamber, (18s) upper plate for refrigeration circuit, (18i) lower plate for refrigeration circuit, (19) axially stationary part of the assembly, (20) axially mobile part of the assembly, (21) hollow or housing-guide for bundle of wires.

Figure no. 1 is a frontal axonometric view in cross section of the mould (10), closed and without wires.

Figure no. 2 is an upper view in plan of the lower 5- part of the mould in the set.

In one of the preferred embodiments, the mould (10) assembled in the injection machine, is comprised of an upper part which comes down over the lower part and is raised again, by means of some vertical upward and downward movements, perfectly programmed, constituting the upper part or semi-mould (10s) in an upper left-hand wire closure support (11s) and an upper right-hand wire closure support (12s), with (11s) and (12s) supporting some wire closures (14d) and (14i) as seen in Figure no.

1. - The lower part or semi-mould (10i) is comprised of some right-hand and left-hand wire closures (13d) and (13i), supported by a left-hand closure support (Ili) and a right-hand closure support (12d).

In the middle section of the semi-mould (10i) and in the form of a longitudinal hollow which crosses the semi mould from left to right, there is a housing-guide (21) for the bundle of wires, over which the grommet element is constructed.

The moulding chamber (17) is refrigerated by means of some plates for the refrigeration circuit (18s) and (18i) which prevent, in the first place, the temperature of the glue introduced in the inside of (17) through the entrance (15) and the duct (16), from damaging the insulation of the wires upon initial contact, so as to contribute afterwards towards the solidification of the glue. The configuration of the chamber (17) depends on the shape of the grommet element.

The machine incorporated into (10) provides it with some movements for the opening, closing, and axial compression of the mobile part (20) over the stationary part (19), as can be seen in Figure no. 2.

The procedure begins with the assembly of the terminals on the ends of the corresponding wires, which is followed by the alignment of various wires and their taping at two adjacent points, thus constituting a bundle of wires.

The bundle of wires is inserted manually into the hollow (21) which is found in the lower part (13d) and (13i), after which follows the descent of the upper part, thus holding in place the two adjacent points of the bundle of wires by means of the pairs (13d)-(13i), and (14d)-(14i).

When said points of the bundle are held in place, the 10- right-hand mobile part (20) of the mould moves towards the left over part (19), at which time the bulging of the wires takes place an the inside of the chamber (17), causing them to separate from each other.

Following this, the glue enters at approximately + 200C and at a pressure of 40 kg/cm2, and passes through the spaces between the wiresand the entire volume of the chamber (17), creating upon cooling a fully insulated solid body.

The configuration of the moulding chamber (17) with respect to shape and dimensions, shall depend on the needs as determined by the quantity and diametre of the wires.

Finally, following this is the surface moulding operation over the entire insulated bundle that has been formed, in order to create the external shape of the grommet according to the needs of the hole in the metal plate through which the wiring will pass, so that the insulation explained above is produced once the grommet is secured.

After observing the drawings and following the explanation we have given about them, it will be seen that the application for a Patent of Invention, with is the motive f or the present Specification, provides a simple and effective construction which may be put into practice with great ease, constituting, without any doubt, a new industrial result.

The machine described forms a complete unit with the procedure which is not liable to function independently, Having sufficiently described the content of the present Patent, together with the drawings attached, it is understood that any modifications in the details deemed suitable may be made.

Claims

CLAIMS:

1 1. A method of manufacturing a grommet element, of the 1k type consisting of a sleeve-plate with elements for 5 positioning and fastening to a plate that separates an engine compartment from a passenger area, and containing electrical wires, providing insulation from noise and from the flow of liquids and gases, including, at least, these two operations:

a) Insulation of the bundle of wires under pressure by the injection of glue at a high temperature in between the wires in the bundle, and b) Surface moulding of PVC or thermoplastic elastomers to give shape to the grommet element as needed.

2. A method according to claim 1, wherein the operation for insulating the bundle of wires comprises, at least, the following operations:

1) Assembly of the wiring with the terminals _n connected, 2) Formation of the bundle and taping it at its two adjacent points, -g- 3) Insertion of the bundle in the lower part of the mould, 4) Closing of the mould, 5) Approximation of the two adjacent points of the bundle by mechanical-pneumatic or hydraulic means to create a bulge in the wires which make up the bundle, 6) Injection of glue into the mould under pressure, at an elevated temperature for a programmed amount of time, 7) Refrigeration of the mould to cause the glue to solidify, 8) surface moulding of the PVC or other thermoplastic elastomer to give shape to the grommet element as needed.

3. A method according to claim 2, wherein the pressure at which the glue enters the mould is between 20 and 70 kg/CM2.

4. A method according to claim 2 or claim 3 wherein the temperature at which the glue enters the mould is between 130C and 250C.

5. A mould for manufacturing grommet elements wherein the mould, according to the procedure, is formed by a semi-mould that includes a left-hand and a right-hand closure support, which support wire closures and a semimould formed by some wire closures which are supported by 5 a closure support.

6. A mould according to claim 5, wherein the middle section of the semimould there is a housing-guide in the form of a longitudinal hollow which crosses the semimould from left to right for the bundle of wires, over 10 which the grommet element is constructed.

7. A mould for manufacturing grommet elements substantially as herein described with reference to the accompanying drawings.

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