INSTRUMENT PANEL

Field of the Invention

This invention is concerned with improvements in instrument panels.

Instrument panels or centre stacks are encountered in many situations but particularly in the automotive industry. For convenience, this invention will be described below in that context. However, it is to be appreciated that the scope of the invention is not limited to the automotive industry.

Background of the Invention

Instruments, such as fuel gauges, speedometers, tachometers and so on are usually mounted in a housing. Most frequently, a plurality of instruments is provided in an instrument cluster housing, the housing being designed to accommodate the various instruments. Conventionally, the instrument housing is fixed to the vehicle by fasteners, such as screws. The screw heads are then hidden under an appropriate trim for the instrument housing. The present invention is based upon the concept that it is now possible to use a new type of fastener for an instrument panel, instrument cluster, centre stack, housing or instrument, such as a DVD player. For convenience, the word "housing" will be used to denote these and similar applications. The new type of fastener can be hidden and does not require external access to fix or release. Consequently, the need for a separate trim panel can be eliminated. This, in turn, can free up design concepts and change the approach for automotive dashboard design. Obviously, the invention can also have similar effects in other industries.

Disclosure of the Invention

Accordingly, this invention provides a fastening system for an instrument housing, the system including a plurality of fasteners, each fastener including: a) actuating means including a material adapted to contract when activated; b) bias means; and c) a flexible core located between the actuating means and the bias means, the flexible core having an engagement means;

wherein the engagement means is moveable upon contraction of the material between a position in which the engagement means engages the instrument housing and a position in which the engagement means disengages the instrument housing, and whereas the bias means biases the flexible core to the engagement position. . .

The instrument housing may be made of any suitable material and of any suitable shape or configuration, such that it is capable of being engaged in the appropriate way by the engagement means. For example, the housing may have a rim or flange suitable for engagement by the engagement means. The housing may be that on a vehicle dashboard, or an element associated with an instrument or an instrument itself.

Preferably, the flexible core substantially insulates the actuating means from the bias means.

It is preferred that the flexible core is made of a suitable plastic material and that the bias means is a steel leaf spring. The invention is not limited to these embodiments, however.

The actuating means is preferably a punched shape memory alloy profile. Examples are shown in the drawings. However, it is within the scope of the invention that the actuating means includes or comprises one or more strands or wires of smart material, or is otherwise of a different construction to those shown in the drawings.

The smart materials with which this invention is concerned are those known as "shape memory" materials. Currently, the best known of these is a shape memory alloy, predominantly or wholly made of titanium and nickel, but which may also include other material, such as aluminium, zinc and copper. Such a shape memory alloy is capable of adopting one shape below a predetermined transition temperature and changing to a second shape once its temperature exceeds the transition temperature. Conversely, when the shape memory alloy cools below the transition temperature, it is capable of adopting the first shape again. While this invention encompasses use of the shape memory alloy referred to above, it is not limited to this material. It is contemplated that other suitable materials may exist now or may come into existence in the future which can be substituted for the shape memory alloy.

Preferably, the material which contracts when activated, is a shape memory material which, when sufficient energy in the form of an electrical current is applied, heats to or above a temperature at which the material shrinks by about 3 to 5%. On application of energy such as electrical energy in order to generate heat above a predetermined level, the actuating means can contract to move the engagement means away from engagement with the housing, thereby releasing the housing. Conversely, if the shape. memory material is permitted to cool below the transitional temperature, the fastener may assume the engagement position and the housing may be fastened again. If the system is required to work under relatively high ambient. temperatures, a high temperature ternary alloy shape memory material may be employed.

The engagements means may take any suitable form. For example, the engagement means may take the form of a projecting wedge which can key into a corresponding recess in. a wall of the housing or which can otherwise retain the housing in the desired configuration. Other forms of the engagement means are within the scope of the invention. For example, the engagement means may be a peg, may include a groove or may take another form.

When the engagement means is moved from the engagement position to the disengagement position, it may be moved in any suitable manner. For example, if the engagement means is located at one end of the core, movement of the engagement means from the engagement position to the disengagement position may describe an arc. As another example, contraction of the actuating means may cause the engagement means (and the core) to be moved axially, so that the engagement means moves out of engagement with any element which it would otherwise fasten.

Preferably, the actuating means consists of or comprises shape memory alloy which contracts when activated by the application of an electrical current, to raise the temperature of the shape memory alloy to the appropriate temperature. For this purpose, the shape- memory alloy material may be connected electrically in any suitable manner. It may be convenient to include a suitable microprocessor in any electrical connector, for operation of the fastener.

If desired, the fasteners may include means to insulate the fasteners, or part of them, thermally. As an example, a suitable piece of insulation, or insulating layer, may be applied to the actuating means or to another appropriate part of a fastener, to help control heat applied to the shape memory alloy.

It is also within the scope of the invention that a fastener, or part of it, can form part of a circuit which can indicate whether the fastener in engaged or disengaged from the housing. As an example, the bias means when in the preferred embodiment of a steel leaf spring may be designed to contact a conductive material on the housing to indicate whether the fastener is engaged or disengaged... When the leaf is in electrical contact with the conductive material, a circuit can be completed. An enquiry can be made by applying current to the fastener, so that if the leaf is in electrical contact with the conductive material, a report can be sent that the fastener is engaged. Conversely, if the circuit cannot be completed because the leaf is not in contact with the conductive material, the report will indicate that the fastener is not engaged.

Rather than making a specific enquiry, a current may be applied continually to each fastener, for a constant indication of whether each fastener is engaged or disengaged. The fasteners may be 'controlled through a network, such as a controller area network (CA-N). Individual fasteners may be addressed (each fastener including an appropriate address means) and be engaged or disengaged in a desired sequence.

The fastening system of the invention may be used to indicate tampering - especially in relation to costly instruments, such as global positioning by satellite instruments (GPS). For example, if a fastener is forced to disengage other than in an authorised way, the ^' disengagement may be designed to prevent the instrument from operating.

Further examples of fasteners which may be used with the fastening system of the invention are discussed in a separate PCT application being lodged concurrently herewith and which claims priority of Australian Patent Application No. 2005906986. The contents of the PCT application are imported herein by reference to illustrate such fasteners.

Power and/or data may be fed to the fasteners through an appropriate microprocessor, which may also include integrated sensors to detect ambient temperatures and shape memory alloy resistance changes, for example. The microprocessor, such as an ASIC controller PWA, may be able to log cycle count, user access codes and statistical data.

The invention further provides a fastening system in connection with an instrument housing, wherein the housing is biased toward engagement with the

fastener. The necessary bias may be provided by any suitable means, such as one or more pre-loaded springs, or pre-loaded foam.

Brief Description of the Drawings

The invention will now be described in connection with certain non-limiting embodiments, in relation to the attached drawings.

In the drawings:

Figure 1 is a front elevation of a first embodiment of a suitable fastener for use according to the invention;

Figure 2 is a rear elevation of the same embodiment; Figure 3 is a sectional view taken along the line A-A of Figure 2;

Figure 4 is an exploded view of a second embodiment of a suitable fastener for use in accordance with the invention, similar in many respects to that of Figures 1 to 3;

Figures 5, 6 and 7 show embodiments of engagement means; Figures 8 and 9 show different embodiments of electrical connectors;

Figure 10 shows in side sectional view the fastener of Figures 1 to 3 in the rest position, ready for engagement;

Figure 11 shows the same embodiment in the engagement or locked position;

Figure 12 shows the same embodiment in the disengagement or fully actuated position;

Figure 13 shows the same embodiment in the rectilinear position;

Figure 14 is a sectional view of the system of the invention securing a housing, the housing assembly being biased with preloaded foam;

Figure 15 is a sectional view of the system of the invention securing a housing, the housing assembly being biased with preloaded springs;

Figure 16 is a sectional view of an embodiment of one of the fasteners having a tamperproof engagement means;

Figure 17 is a sectional view of an embodiment of one of the fasteners having a wedge lock engagement means;

Figure 18 is a sectional view of an embodiment of one of the fasteners having a contacts to detect the engaged position;

Figure 19 shows integration of the fasteners into an instrument panel substrate and console chassis; and

Figures 20 and 21 show in conceptual form how a fastener for use in the invention may curl forward at rest, and may shrink axially as well as pull back when actuated.

Detailed Description of the Drawings

Referring first to Figures 1 to 3, fastener 10 is shown having actuating means 12 made of shape memory alloy (SMA) material as a punched profile. Bias means 14, a thin (less than 0.5mm) punched electroplated spring steel leaf, is located on one side of flexible core 16, while SMA profile 12 is located on the other side. This arrangement forms a sandwich, with SMA profile 12 being separated from leaf spring 14 by core 16.

Flexible core 16 is a 1 mm plastic moulding, produced by injection moulding and being made of 10% glass filled Nylon. Core 16 has, at one end, engagement means 18. As can be seen in Figure 3, engagement means 18 is in the form of a projecting wedge, which can key into or retain an element (see Figure 11, for example).

Wedge 18 is movable, upon contraction of the SMA profile 12, between an engagement position and a disengagement position. Leaf spring. 14 biases the wedge 18 to a default engagement position, which is that shown in Figures 1 to 3 for this embodiment.

SMA profile 12 is shown in Figure 2 as having two legs 24 and 26, forming gap 28 between them. Core 16 includes six moulded projections 30 and a six pairs of extensions 32, in both cases to secure profile 12 to core 16. Projections 30 and extensions 32 can permit profile 12 to slide relative to core 16 should contraction of profile 12 occur axially, as discussed further below. Leaf spring 14 includes tang 20 which fits through an aperture (not visible in these Figures) in core 16 and into a complementary slot 22 in SMA profile 12.

Two gold flashed brass mounting pins 34 pass through each of leaf spring 14, core 16 and SMA profile 12. Each pin 34 may be suitably insulated electrically from leaf spring 14, for example, by plastic clamping plate 36 (refer Figure 1). Each pin 34 is connected electrically with SMA profile 12 by pressed gold flashed brass circular sleeves 38.

As a result of the mating of tang 20 with slot 22 (sandwiching core 16), the mating of projections 30 and extensions 32 with legs 24 and 26, and the insertion of pins 34 through the assembly, fastener 10 is held firmly together.

When a fastener such as fastener 10 is pressed into an instrument housing (not shown in these Figures), barbs 42 of pins 34 can bite into a mating moulded detail (refer Figure 4), Pins 34 are connected to a suitable ASIC based controller PWA (not shown). On actuation, SMA profile contracts and draws fastener 10 (and , wedge 18) to the right, referring to Figure 3. Thus wedge 18 can be drawn out of engagement with a housing or the like. On release and cooling, leaf spring 14 rebiases SMA profile 12 and forces fastener 10 back to the engagement position.

If each of legs 24 and 26 measures about 4.0 x 0.2 mm, SMA profile 12 can have an equivalent strength of about fifty strands of 8/thousandth of an inch SMA wire. At 180 Mpa, SMA profile 12 can provide approximately 294 N of pulling force.

Reference is now made to the embodiments in Figures 4 to 9. In describing these Figures the same reference numerals will be used for the same or similar parts.

In Figure 4, and similarly to Figures 1 to 3, fastener 10 has SMA profile 12, leaf spring 14 and core 16. SMA profile 12 has two legs 24 and 26, forming gap 28 between them. Leaf spring 14 includes tang 20 which fits through aperture 40 in core 16 and into a complementary slot 22 in SMA profile 12. Part of core 16 is shown in cut away form so that projections 30 and extensions 32 can be seen.

Instead of wedge 18, core 16 may have other another form of engagement means, such as peg 46 (Figure 5), ramp 48 and groove 50 (Figure 6) or "reverse wedge" 52 (Figure 7). These are some of many types of engagement means which may be suitable. Further examples are shown in Figures 16 to 18.

Mounting pins 34 in this embodiment include barbs 42 as well as electrical terminals 44. Barbs 42 help to secure the components of fastener 10. Mounting pins 34 pass through clamping plate 36, leaf spring 14 (through apertures 72), core

16 (through apertures 72) and SMA profile 12, before entering mount 54 to connect to electrical connector 56.

Connector 56 is shown with side cabling 58. An alternate style of electrical connector is shown in Figure 9, where connector 60 has cabling 58 at the rear.

Yet another arrangement is shown in Figure 8, where each leg 24 and 26 of SMA profile 12 has a tapered foot 62, designed to fit into slots 64 in connector 66, which has cabling 58 at the base,

Reference is now made to Figures 10 to 13, which show integration of fastener 10 into an instrument panel detail. In Figure 10, fastener 10 is shown in the "at rest" position. Leaf spring 14 is designed so that at rest it biases core 16 and SMA profile 12 upwards (with reference to the Figure). Fastener 10 is attached to a suitable processor module 74.

Tn Figure 1 1 , fastener 10 has been pushed into contact with housing edge 76. Wedge 18 bears against edge 76 to hold housing edge 76 in place. When SMA profile 12 is actuated via module 74, profile 12 contracts against the bias of leaf spring 14 and draws fastener back as shown in Figure 12. It can be seen that fastener 10 is drawn back into shroud 78 and that wedge 18 is pulled out of engagement with edge 76.

In Figure 13, fastener 10 is shown in the rectilinear position. Fastener 10 can pass through this position as it cools, to move from the disengaged position in Figure 12 to the engaged position in Figure 11. Figure 13 also illustrates how fastener 10 may appear in the "at rest" position (in contrast to that in Figure 10) if spring leaf 14 has less bias.

If desired, fastener 10 as shown in Figures 10 to 13 may be operable by a manual release (not shown), in case of power failure.

In Figure 14, two fasteners 10 are shown in position engaged with housing 80 at edge 76. One of fasteners 10 is enlarged to show detail. Wedge or overhang 18 engages edge 76 as in the previous Figures 1 1. Foam 82 biases housing or instrument panel 80 as shown by arrow 200, so that there is positive engagement between fastener 10 and edge 76. .

Figure 15 is similar to Figure 14, except that preloaded springs 84 are substituted for foam 82 biasing housing or instrument panel 80 as shown by arrow 2002. Springs 84 are contained within compartments 86.

It will be appreciated by one skilled in the art that fasteners 10, especially in the environment created by foam 82 or springs 84, can apply a constant preload on the assembly. This can greatly assist in eliminating rattle and squeak in the instrument panel.

Other methods could also be used in relation to the Figure 14 and 15 assemblies, such as foam tape, friction ribs, etc. Power and data to fasteners 10 may be supplied via the instrument panel feed, if desired. Such power may be preconditioned, so avoiding need for additional power conditioning electronics.

In Figure 16, edge 76 may include a tamper proof ledge 77, to prevent access to fastener 10 and hence to avoid tampering. Fastener 10 may also be connected to a slave fastener (not shown).

In Figure 17, fastener 10 has, as well as wedge 18, a wedge lock part 88, to ensure a fixed and tight location and engagement between fastener 10 and edge 76.

In Figure 18, edge 76 includes metal edge strip 90, designed to make electrical contact with leaf spring 14. If leaf spring 14 is in contact with metal edge strip 90, a circuit may be closed and a signal may be given to show engagement. Conversely, if contact if broken, the signal will show disengagement.

Figure 19 shows how a fastener 10 may be integrated into an instrument panel substrate and a console chassis. In this Figure, wedge 18, in the engaged position, enters through aperture 92 and engages chassis 94 of a detachable radio face plate for radio 96.

It is also within the scope of the invention that contraction of SMA profile 12 after activation occurs axially, rather than causing fastener 10 to move from a convex configuration to a flat configuration, as described above, or to curl back, as described below, or that both types of movement occur together. Figures 20 and 21 illustrate this. In Figure 20, leaf spring 14 is biasing fastener 10 so that it curls to the left of the Figure. When activation of SMA profile 12 occurs, SMA profile 12 shortens Referring to Figure 4, shrinkage would occur in the dimension

represented by arrows 70. Because of engagement of tang 20 through aperture 40 into slot 22, core 16 and leaf spring 14 would be forced to move downwardly towards mounting pins 34. (Apertures 72 in core 16 and leaf spring 14, of which only two are labelled, would need to be elongated for this purpose.) Wedge 18 would move downwardly with reference to Figure 4, out of engagement with any housing it was engaging. Figure 21 shows how fastener 10 has shrunk and hence moved away from contact between wedge 18 and any housing.

It will be apparent to one skilled in the art that variations may be made to the invention described herein without departing from the spirit or scope of the invention.

Industrial Applicability

As will be readily appreciated by those skilled in the various arts, the invention disclosed herein is not limited to the examples set out and has wide application in many areas. The invention represents a significant advance in the art of securing and releasing, particularly in connection with instrument panels in the automotive industry