Patent Description:
Highly resistant polyurethane foam sealing of single wires or wire bundles is a standard sealing for firewall grommets. Polyurethane foam can be used also for other applications, for example splice over molding, rigid wiring and ring terminal sealing cups.

The common way of creating polyurethane product on wires harnesses is injection of polyurethane material into a mold (or mould) through which wire harness is passing.

Nowadays, in wire / harness molding process, operators need to take extra care to manually shape the wire / wire harness in the mold to ensure that no wires are touching the mold. However, after the closing of the mold, there is no feedback or insurance that wires are still in the desired position. This has at least the following disadvantages: there is a risk of damaging the wires during the closing of the mold, there is difficulty to place the wire / harness and position it in the mold, there is a risk of visible wires after molding process on product surface, and there is a risk of short circuit.

Customer-specific wiring harness production is bringing challenge which is wire harness diameter depended from the car specification ordered by the end customer. With high content wire harness, there is a risk that wires can touch the mold surface (i.e. cavity surface of the mold) which can lead to jeopardizing sealing capabilities of the overmolding part and to create the risk of shortcut. That is to say, the wire touching the mold surface is not fully covered by the polyurethane and thereby the wire is not fully over molded and badly protected.

Additionally, there is a need to (over) mold very long components on the harness. This leads to the situation where a wire harness or generally speaking a piece to be maintained, under its own weight or due to geometry, can sag within the mold, thereby causing the same risk as described before. That is to say, the wire (or wire harness, or a part of the bundle) may fall down due to its own weight and touch the mold, so that said wire will not be correctly over molded by the sealing material (such as polyurethane), and thereby will be badly protected. The same situation may be caused by 3D shape of the product, like twisted S shape which even in vertical mold can cause issues (that is to say issues are not only due to gravity but also shapes of the parts). The document <CIT> discloses a spacer for two or more cables or cable cores comprising a star-shaped body of stiff material having radial arms locating the cores or cables at a predetermined distance from each other, and an annulus of stiff material encompassing said cables or cores.

However, there is not the possibility of adjustment to a variety of cable diameters nor the possibility to correctly allow the molding of the sealing material therein, due to the plain shape and the sealing flow resistance.

Therefore, there is a need for another kind of solution that is a good trade-off for overcoming the different drawbacks of the prior art.

In particular, there is a need to solve the problems of decentralization of pieces to be maintained such as a wire harness within the mold during sealant (e.g. polyurethane) process, of wire harness sagging within the mold (especially with long and/or 3D products), and of minimum distance of harness to the mold and its effect on polyurethane over molding surface. State of the art is disclosed in <CIT>, <CIT>, <CIT>, <CIT> and <CIT>. <CIT> discloses a spacer having rectilinear flexible leaves.

The present disclosure concerns a spacer for maintaining one or more pieces during a molding process, the spacer having:.

The invention is exposed in the enclosed set of claims.

A leaf may be defined as a thin sheet or plate of any substance. That is, the spring curved leaf is a leaf which is curved, is flexible and allows for a spring effect (elastic return force). Flexible is to be understood as capable of movement, in contrast with the external frame which is rigid. What is to be understood by wrap may be to envelop and secure for transportation or storage, that is to say to embrace, to enfold, or to surround. A spacer is a device or piece used to create or maintain a desired amount of space, that is to say to maintain a distance between the one or more pieces to be maintained (e.g. wires) held by the spacer and the mold (in particular inner surface of the mold, that is to say in the mold cavity surface).

This allows to provide an easier manufacturing of the spacer and the one or more pieces to be maintained (e.g. wires) to be over molded, in particular for easy installation on a wire harness (or harnesses, or wire(s)). An over molded wire or overmolded piece to be maintained, is understood as a wire or a piece to be maintained which is covered or surrounded by a sealing material, such as polyurethane. The one or more pieces to be maintained may be one or more wires. Instead of (electrical) wires, pneumatic tubes, fiber optics, and the like may also be present in the bundle or being even directly wrapped by the spacer, and are examples of pieces to be maintained (or clamped). That is, a wire is something (such as a thin plant stem) that is wirelike in a general meaning; or to be more specific, an electrical wire and the like.

Further, this allows to provide a spacer, also called fishbone insert, which could be preinstalled on the piece(s) to be maintained, wire(s), or harness(es), to firstly ensure that all around the harness there is a minimum distance to the mold surface, to secondly eliminate harness sagging by supporting its weight, and thirdly ensure that harness routing passing the mold is substantially following nominal center line (in particular theoretical nominal center line designed by CAD, computer-aided design, e.g. 3D CAD). The spacer can be called a fishbone insert because it can be defined as a set or network of elongated components (like bones of a fish, corresponding to the spring curved leaves) having free ends and connected by fixed portions to a spine (corresponding to the external frame) being a skeleton or a structural framework.

Still further, this allows to provide a spacer or fishbone insert designed to cover all harness diameters, in particular within a car project. This allows to be designed as a single piece component which can be simply clipped on the pieces to be maintained, on wire harness or a few-part component which can be assembled on the harness with usage of its own locks or additional component such as cable ties.

That is, the spacer according to the present disclosure allows to provide a correct centralization of the pieces to be maintained (e.g. wire harness) inside the mold prior to injection process, to eliminate (limit, suppress or compensate) the wire harness sagging under its own weight, to eliminate (limit, suppress or compensate) wire harness sagging due to 3D shape of polyurethane component, and additional tension brought with this, to correct flow of polyurethane material to the wires, and to provide compatibility with polyurethane foam not to lower or decrease sealing function.

The present disclosure significantly improves spacer and molding process, especially the part which is operator dependent and then completely random.

The spacer according to the present disclosure thereby allows for an easier wire / harness placement in the mold, an easier spacer installation on the wire / harness, the elimination of loose wires which can be smashed during closing of the mold, the elimination of visible wire after the molding process, the elimination of short circuit risk due to wires visible on sealing material (such as polyurethane) product surface, and more flexibility in matter of processing different harness diameters.

The spacer according to the present disclosure enables development of a completely new line of polyurethane composite products, which could be more compact as spacers eliminate the need to design with extra wall thickness in order to compensate harness or single wire displacement from the center line.

Advantageously, the free ends are movable between :.

Advantageously, the first wrapping portion and the second wrapping portion are defined by a surface of the free end arranged to be in contact with the one or more pieces to be maintained (e.g. wires). That is, the first wrapping portion and the second wrapping portion can be a plurality of lines of contact (or surfaces or thin surfaces) of the free ends on the one or more wires. The difference between the first wrapping portion and the second wrapping portion is that they are placed in different diameters to allow different diameter of wires to be held in place.

Advantageously, the first wrapping portion and the second wrapping portion are cavities receiving the one or more pieces to be maintained (e.g. wires).

Advantageously, each free end is arranged to be in contact with the one or more pieces to be maintained.

This allows to provide an improved support to the one or more wires, in particular to allow for a flexible support and an adjustment in case of introduction of wires of different diameters. That is, the spacer allows to receive wires of different diameters, or to better maintain a plurality of wires at the same time.

Advantageously, the free ends extends inwardly.

Advantageously, the spring curved leaves extend in a direction having a radial component and a tangential component.

Advantageously, the external frame has an external surface (or external face) and a groove for a cable tie arranged on the external surface, preferably circumferentially.

This allows to facilitate the fixation of the spacer holding the one or more wires with a cable tie.

Advantageously, the spacer further has a hinged portion and a lock portion, preferably opposed to the hinged portion, and wherein the spacer is arranged to define :.

This allows to facilitate the manufacturing of the one or more over molded wires, in particular by facilitating the introduction of the one or more wires in the spacer so as to be held in place.

Advantageously, the spacer further has at least one lock portion.

This allows to provide a fixation system between two portions of the spacer, thereby facilitating the manufacturing.

Advantageously, each spring curved leaf has a curvature with an internal curved portion and an external curved portion, and the plurality of spring curved leaves is arranged so as to contact the one or more pieces to be maintained on the internal curved portion or on the external curved portion.

In other words, each spring curved leaf extends at an oblique angle from the inner face of the external frame and has a curvature such that the free end of each curved leaf is configured to contact the one or more pieces to be maintained on a concave side of the curvature or on a convex side of the curvature.

This allows to improve the support of the one or more pieces to be maintained (e.g. wires).

Advantageously, the external frame has at least one outside pin.

This allows to improve the positioning of the spacer by locating the outside pin in a corresponding (milled) pocket of the mold. In another variant, the pin is only touching the cavity surface, assuring that no outer face of the insert is not visible, to allow to have more sealant on the outside for a better mechanical integrity. Advantageously, the spacer is made out of plastic or resin, and could be integrally formed.

This allows to provide an easy manufacturing.

A second aspect of the present disclosure concerns a method for over molding one or more pieces to be maintained, the method comprising the steps of:.

This allows to facilitate the manufacturing and the over molding of one or more pieces to be maintained (e.g. wires). This also allows to have the above mentioned effects and advantages, as explained with respect to the first aspect.

Advantageously, the method further has the step of:.

This allows to manufacture the one or more over molded wires and to extract it from the mold.

Advantageously, the spacer has an external frame with at least one outside pin, and the method further has the step of :.

This allows to provide an improvement of the localization of the spacer in the mold, so as to ensure the correct over molding of the one or more wires.

Other features, purposes and advantages of the disclosure will become more explicit by means of reading the detailed statement of the nonrestrictive embodiments made with reference to the accompanying drawings.

The present disclosure relates to a spacer for allowing space between pieces to be maintained and a mold, in a molding process, so as to provide high quality over molding of the pieces.

<FIG> illustrates three spacers <NUM> according to a first embodiment with pieces to be maintained <NUM> therein, in a mold <NUM>. In the present embodiment, the pieces to be maintained <NUM> may be wires.

The mold <NUM> has an entry portion <NUM> and an exit portion <NUM>.

Each spacer <NUM> is positioned in the mold <NUM>. The wires <NUM> are positioned inside each spacer <NUM>, and follow the path defined by both the spacers <NUM> and the mold <NUM>.

A sealing material, such as polyurethane (PUR), can be introduced in the mold <NUM>, in order to over mold the pieces to be maintained (e.g. wires) <NUM>. Injection channel and air vents are not represented in the drawings. The mold <NUM> may be adapted for PUR foaming process or PUR potting process, in particular with respect to entry portion <NUM>, exit portion <NUM>, injection channel and air vents , and the like, as necessary.

That is, as the spacers <NUM> allows to avoid that the pieces to be maintained (e.g. wires) <NUM> directly touch the mold <NUM>, the pieces to be maintained (e.g. wires) <NUM> can be entirely over molded and correctly protected, without any piece to be maintained (e.g. wire) <NUM> uncovered by the sealing material.

<FIG> illustrates the spacer <NUM> according to the first embodiment, in another mold <NUM>. The other mold <NUM> has also the entry portion <NUM> and the exit portion <NUM>.

The wires are examples of pieces to be maintained, and the description is generally applicable to any piece to be maintained.

For sake of brevity, the term wire is used hereafter. The spacer <NUM> maintains the wires <NUM> in a desired path, so that none of the wires <NUM> directly touch the mold <NUM>. Thereby, a correct over molding of the wires <NUM> is achieved.

<FIG> illustrates the spacer <NUM> according to the first embodiment with a first wire <NUM> therein, which is an example of a first piece to be maintained. The first wire <NUM> is an example of wires <NUM>, and may also be a bundle or a harness having the same shape of first wire <NUM>.

The spacer <NUM> has an external frame <NUM> supporting a plurality of spring curved leaves <NUM>. Each of the spring curved leaves <NUM> has a fixed end <NUM> attached to an inner face (or inner surface) of the external frame <NUM>. Each spring curved leaf <NUM> further has a free end <NUM>. The free ends <NUM> are arranged to flexibly wrap the first wire <NUM> as shown in <FIG>. That is, the free ends <NUM> of the spring curved leaves <NUM> defines a first wrapping portion <NUM>, having a first diameter matching with the diameter of the first wire <NUM>. The free ends <NUM> are represented in <FIG> in a first position. Each free end <NUM> is arranged to be in contact with the first wire <NUM>. Thereby, a flexible support and wrapping is provided to the first wire <NUM>. That is, each spring curved leaf <NUM> extends at an oblique angle from the inner face of the external frame <NUM> and has a curvature such that the free end <NUM> of each curved leaf <NUM> is configured to contact the first wire <NUM> on a concave side of the curvature (or on a convex side of the curvature as illustrated in <FIG> ). In other words, the spring curved leaf <NUM> has an elongate shape with the fixed end <NUM>, also called proximal portion, supported by the external frame and projecting inwardly (i.e. to an inside of the spacer <NUM>), and with the free end <NUM>, also called distal portion. The distal portion is provided with a contact surface (or a contact line) arranged to contact the first wire <NUM> and maintain it, in cooperation with the other contact surfaces of the other spring curved leaves <NUM>.

<FIG> illustrates the spacer <NUM> according to the first embodiment with a second wire <NUM>, which is an example of a second piece to be maintained.

The reference number are kept as far as possible with respect to the different figures.

The second wire <NUM> is an example of wires <NUM>, and may also be a bundle or a harness having the same shape of second wire <NUM>.

The free ends <NUM> of the spring curved leaves <NUM> defines a second wrapping portion <NUM>, having a second diameter matching with the diameter of the second wire <NUM>. The free ends <NUM> are represented in <FIG> in a second position. Each free end <NUM> is arranged to be in contact with the second wire <NUM>. The diameter of the second wire <NUM> is greater than the diameter of the first wire <NUM> in the example shown in <FIG>.

Thereby, a flexible support and wrapping is provided to the second wire <NUM>, with the same spacer <NUM> as for the first wire <NUM> having a smaller diameter.

In other words, the free ends <NUM> are movable between :.

The first position corresponding to the first wrapping portion <NUM> may be considered as a rest position when no load is applied on the free ends <NUM> (and on the spring curved leaves <NUM>), due to a nominal diameter corresponding to the first wire <NUM>. The second position corresponding to the second wrapping portion <NUM> may be considered as a work position when a load is applied on the free ends <NUM> (and on the spring curved leaves <NUM>), due to the diameter of the second wire <NUM> which is bigger than the nominal diameter.

Further, the spring curved leaves <NUM> allows for an improved flow resistance of the sealing material (e.g. polyurethane) when introduced in the mold <NUM>, so as to facilitate the correct repartition of the sealing material in the mold <NUM> and improving the correct over molding of the wires <NUM>.

In an embodiment, it is to be noted that the fixed end <NUM> may be attached to the inner face of the external frame by a flexible anchoring portion, to further adjust and improve the flexibility of the spring curved leaves <NUM>.

<FIG> illustrates the spacer <NUM> according to a second embodiment with a hinged portion <NUM>, in an opened position.

The reference number are kept as far as possible between the different figures and different embodiments.

In the opened position, the wires <NUM> can be easily placed in the spacer <NUM>, and the spacer <NUM> can be closed thereafter.

The spacer <NUM> may have a lock portion having a hook <NUM> and a groove <NUM> arranged to retain the hook <NUM>. Thereby, the spacer <NUM> can be maintained in a closed position and retain the wires <NUM>.

<FIG> illustrates the spacer <NUM> according to a third embodiment with a groove <NUM> for a cable tie.

That is, after the wires <NUM> are being over molded with the sealing material, the groove <NUM> may receive a cable tie (not shown) in order to fix the over molded wires <NUM> onto a support or the like, for final use of the wires <NUM>. The groove <NUM> is preferably circumferential is order to receive the cable tie. The groove <NUM> is preferably placed on an outer surface of the external frame <NUM>, the outer face being opposite to the inner face.

In another aspect, it is possible to use the cable ties as a fixation method for the insert itself, to keep both half portion locked together on the harness, especially with a big harness inside <FIG> illustrates the spacer <NUM> according to a fourth embodiment with lock portions.

The spacer <NUM> may have for example two lock portions having the grooves <NUM> and the hooks <NUM>, so as to maintain the spacer <NUM> in the closed position. The grooves <NUM> are arranged to cooperate with the hooks <NUM> so as to maintain the spacer <NUM> in a closed position. <FIG> illustrates the spacer <NUM> according to a fifth embodiment with a rectangular external frame <NUM> and outside pins <NUM>.

The rectangular external frame <NUM> is an example of external frame <NUM>.

The external frame <NUM> has outside pins <NUM>. The outside pins <NUM> may be located in milled pockets of the mold <NUM> so as to better placed and locate the spacer <NUM> in the mold <NUM>. Also, they can be used to create space for sealant to fully cover the outside face of the external frame.

As illustrated in <FIG> , each spring curved leaf <NUM> extends at the oblique angle from the inner face of the external frame <NUM> and has the curvature such that the free end <NUM> of each curved leaf <NUM> is configured to contact the one or more pieces to be maintained <NUM>, <NUM>, <NUM> on a convex side of the curvature. This is to be compared with <FIG> wherein the contact between the one or more pieces to be maintained <NUM>, <NUM>, <NUM> is on the concave side of the curvature. It is to be noted the oblique angle may be adapted according to the configuration. That is, each of the spring curved leaves <NUM> has the curvature. The wrapping portion <NUM> is represented in <FIG> and is defined by external portions of the spring curved leaves <NUM>, on an external side of their curvature, that is to say on the convex side of the curvature.

In contrast, in <FIG> , the wrapping portions <NUM>-<NUM> are formed by internal portions of the spring curved leaves <NUM>, on an internal side of their curvature, that is to say on their concave side.

<FIG> illustrates the spacer <NUM> according to a sixth embodiment with an oval shape.

The spacer <NUM> has an oval shape so as to be adaptable to a desired shape of the over molded wires <NUM>.

The spacer <NUM> is also represented with the hook <NUM>, the outside pins <NUM>, the external frame <NUM> and the spring curved leaves <NUM>.

That is, the spacer <NUM> according to the above embodiments, also called fishbone inserts, are designed to ensure that the spacer <NUM> is suitable to accommodate differences in harness/wire diameters with constant outer diameter of the space, so as to match the mold cavity of the mold <NUM> and match the shape of the final product.

The spacer <NUM> has a plurality of spring curved leaves (also called internal leaves) which are flexible and can bend accordingly to match the shape and size of harness/wire inside.

It can also be applied on single wires or any other object to be over molded. The internal structure could also be shaped to fit a rectangular shape (as shown in <FIG> ) with spring like structures having the same final effect.

Outside walls of the spacer <NUM> (i.e. external frame <NUM>) are thick enough so as to keep their geometry and diameter constant.

The spacer geometry can be adjusted according to the sealing final desired shape. The same applies for further consideration of the quantity and shapes of spring curved leaves <NUM> inside the spacer <NUM>.

After closing the mold, injection of sealing material (e.g. polyurethane) is performed.

Due to the spring curved leaves <NUM>, the sealing material can easily flow between them assuring correct filling of the mold <NUM> and stable molding process.

The spacer <NUM> can be made from material compatible with the sealing material to ensure a good adherence. The sealing material is preferably polyurethane but can also be PVC, PA, TPU or any suitable material.

After the process, the final product (i.e. the one or more over molded wires / harnesses / bundle) can be de-molded (i.e. removed from the mold <NUM>).

Claim 1:
A spacer (<NUM>) for maintaining one or more pieces (<NUM>, <NUM>, <NUM>) during a molding process, the spacer (<NUM>) having:
- an external frame (<NUM>), and
- a plurality of spring leaves (<NUM>),
wherein each spring leaf (<NUM>) has a fixed end (<NUM>) attached to an inner face of the external frame (<NUM>) and a free end (<NUM>), and
wherein the free ends (<NUM>) of the plurality of spring leaves (<NUM>) are arranged to flexibly wrap the one or more pieces to be maintained (<NUM>, <NUM>, <NUM>)
characterize in that :
- each spring leaf is a spring curved leaf that has, in a rest position, a curvature such that the free end (<NUM>) of each curved leaf (<NUM>) is configured to contact the one or more pieces to be maintained (<NUM>, <NUM>, <NUM>) on a concave side of the curvature or on a convex side of the curvature, and
- each spring curved leaf (<NUM>) extends, in the rest position, at an oblique angle from the inner face of the external frame (<NUM>).