GB2064506A - Adhesive bonding of metal members to non-metallic supports (e.g. windscreens) by magnetic induction heating - Google Patents

Abstract

In a method of bonding a metal member e.g. a base for a rear view driver mirror to a support e.g. a vehicle windscreen, in which bonding is effected by a body of adhesive material using a process which involves heating, in order to economise on heating power and heating time, such heating is effected using magnetic induction heating means comprising a coil or loop which is disposed adjacent the metal member and of which at least a portion lies on the same side of the metal/adhesive interface as the metal member. Preferably, preheated mirror- mounts 1 (Fig. 3) are fed to notches 22 of inverting wheel 21 (seen edge- on in Fig. 4) whence they are ejected by finger 20 into aperture 23 in locating member 33 having magnetic induction heating loop or coil 31, and then pressed onto laminated windscreen 11 by descent of punch 24 having duct 32 for supply of adhesive. (Alternatively, the mounts are pre-glued). <IMAGE>

Description

SPECIFICATION Method and apparatus for bonding metal elements to non-metallic supports The invention relates to a method of bonding a metal member to a non-metallic structural support, particularly but not exclusively, a sheet of glass or vitreous material, in which the metal member is assembled to the support and is bonded thereto by a body of adhesive material using a process which involves heating.

It is known to attach metal members to supports by gluing, using adhesive materials.

Such materials are used when the nature of the support prohibits the use of one of the well known techniques of connecting metal members, generally performed at elevated temperatures. The materials are also used to connect the metal members to supports when the conditions in which the assemblies are used are such that the stresses to which they are subjected do not justify the making of an assembly by any other techniques.

It is also known to effect and/or speed up bonding of the adhesive material by the use of heat.

By way of example, metal members may be attached by means of adhesive materials to allglass type windows or doors, which do not use movable frames. Such windows or doors are formed by sheets of glass to which the locks and/or other pieces of metalwork are attached directly. The sheets of glass can be tempered or not, in dependence on their use. For instance, untempered sheets can be used for furniture. In contrast, sheets of glass used in building are preferably tempered.

Another example is the attachment of metal driving mirror bases to motor vehicle windscreens.

In motor car manufacture it is current practice to attach the driving mirror to a particular place on the inner surface of the windscreen. The driving mirror assembly can be attached directly to the windscreen. It is preferred to glue to the windscreen a base or some element for supporting the driving mirror. Such bases or supports consist of relatively small metal members adapted for the mechanical attachment of the driving mirror. As a rule the bases are glued at a selected place on the inner surface of the windscreen before the latter is mounted on the vehicle.

The examples just described fall within the scope of gluing metal pieces according to the invention. These examples do not limit the invention, which also relates to the gluing of metal members on to non-metallic structural supports which differ in shape and/or nature from those described above. For instance, the support can be made of plastics materials.

In the case of supports of or faced with a plastics material, a separate adhesive material can be dispensed with provided that the platics material of the support can be rendered adhesive by heating. This type of application comes within the scope of the method according to the invention.

For mass production, it is more advantageous to glue the metal members mechanically. As a rule this can be done as the support passes along a conveyor, taking up the minimum time, so as not to disturb the rhythm of manufacture.

It is known to attach metal elements to a support, for instance, a metal base element to a sheet of glass, by applying a sheet of adhesive thermoplastics material to à surface of a metal element which has been pre-heated, and then applying the resulting assembly at the selected place on the support, and applying pressure accompanied by magnetic induction heating, the pressure being maintained for a brief time after the induction heating has ceased (US Patent No.

3 242 026). In this process the metal element to be bonded is placed on the side of the support remote from the side where the magnetic induction heating device is disposed. This arrangement requires special arrangements for ensuring the conveying of the support, more particularly in the case of bent sheets of glass. As a result, the apparatus used is relatively complicated.

It is also known to mount a metal driving mirror base on a windscreen support by means of an apparatus comprising a conveyor for the windscreen, above which a device is mounted for applying the mirror base to the windscreen. The arrangement comprises means for the magnetic induction heating of the drIving mirror base before it is put in place on the windscreen (French Patent No. 2 299 235). In this process the driving mirror base is heated upstream of the device for attaching the support by gluing under pressure, and this causes heat losses between the two operations and thus results in poor utilization of the power consumed.

It is an object of the invention to reduce or obviate the disadvantages of the prior art processes, the invention having the advantages which will be disclosed hereinafter.

In its most general aspect, the invention provides a method of bonding a metal member to a non-metallic structural support in which the metal member is assembled to the support and is bonded thereto by a body of adhesive material using a process which involves heating, characterised in that such heating is effected using magnetic induction heating means comprising a coil or loop which is disposed adjacent the metal member and of which at least a portion lies on the same side of the metal/adhesive interface as the metal member.

The feature that at least part of the magnetic induction coil or loop is disposed on the same side of the metal/adhesive interface as the metal member to be bonded produces simplified handling. The arrangement according to the invention makes the process independent of the thickness or bulk of the support. Moreover, the positioning of the coil or loop adjacent the metal member to be bonded improves heating efficiency in comparison with heating performed upstream of the bonding station.

The bond effected in this way may be a firm bond such that the metal member is permanently secured to the support without the need for any further treatment. But in some important embodiments of the invention, the bonding so effected is a preliminary bond only, and the metal member and support are subjected to further treatment in order to ensure firm, permanent bonding.

As has been stated, the invention is particularly suitable for securing mirror bases to windscreens and door or window furniture to all-glass doors or windows, and it is accordingly preferred that said support comprises a vitreous sheet. Such a vitreous sheet may optionally be tempered.

Preferably, said support is a laminated support comprising at least one vitreous sheet and at least one plastics sheet. The invention can thus be applied to bonding mirror bases to laminated panels such as laminated vehicle windscreens.

Laminated windscreens usually fall into one of two categories: first, those consisting of two sheets of glass bonded together by an interlayer formed from one or more films of thermoplastics material, usually polyvinyl butyral, and second, those consisting of a single sheet of glass to which is bonded a thermoplastics sheet for example of polyurethane, polyvinyl chloride or polyvinyl butyral so that the thermoplastics sheet defines an outer main face of the windscreen. In the case of laminated windscreens falling into the second category, it will be appreciated that the exposed thermoplastics layer can itself constitute the adhesive used for bonding the metal member to the support, and thus that though an additional body of adhesive may be used if desired, this is not necessary.

When bonding a said metal member to a nonmetalic support of whatever nature, the adhesive used may be of any desired type. The adhesive may for example be a heat-curable resin adhesive, for example a cyanoacrylate resin, or it may be a thermoplastics adhesive, such as a hot-melt adhesive or a film of thermoplastics material such as polyvinyl butyral, polyurethane or polyvinyl chloride. The use of a hot-melt or thermoplastics film adhesive has the advantage of avoiding any difficulties which may arise due to the evaporation of any solvent or other auxiliary ingredient which could take place during the setting of some other type of adhesive.

Accordingly, it is advantageous that said bonding between the metal member and the support is effected by a body of adhesive material intervening between them, which adhesive material is preferably constituted by a thermoplastics film and is optionally pre-applied to said metal member. Such pre-application of adhesive enables the building up of a stock of adhesive-bearing metal members which have been made independently of a main production line.

In the particular case of a laminated support comprising a thermoplastics film, it is especially advantageous to use a film of the same thermoplastics material for bonding the metal member to the support. This results in increased manufacturing convenience since there is no need to take into account any differences in the nature of the film materials during the final heat treatment of the assembly.

For example, the bonding of a laminated support often takes place in two stages, namely a prebonding stage and a firm bonding stage during each of which heat may be applied to the support.

A first stage consists in the prebonding of stacked sheets with the interposition of a sheet of thermoplastics material; in this stage the stack is heated to a relatively low temperature, generally at sub-atmospheric pressure, to perform degassing and ensure a first connection. The second stage (final or firm bonding), is then performed at elevated temperature and/or pressure, for example, in an autoclave. The application of heat in either or both of these stages for effecting bonding of the support will have no deleterious effect on a bond between the metal member and the support if this is formed before the support is firmly laminated using the same adhesive film material, nor will subsequent bonding of the metal member to the support have any deleterious effect on a prior lamination of the support.

In preferred embodiments of the invention, bonding of a said laminated support is effected in two stages, namely a prebonding stage and a firm bonding stage, and said metal member is bonded to the support between such stages. In this way, a light bonding can be effected between the metal member and the support and this bond can be made firm and final during the firm bonding stage of the laminated support. This results in economies in manufacture in that it saves time and heating power.

In an advantageous embodiment of the invention said loop or at least some turns of said coil surround the metal member to heat it. This feature ensures satisfactory magnetic coupling and enables both the power consumed and the heating time to be reduced.

In a preferred embodiment, the height of the magnetic induction coil or loop is substantially equal to that of the metal member. The result is to optimise the advantages derived from the satisfactory magnetic coupling.

Whether or not adhesive is pre-applied to the metal member, and whatever the form of the adhesive material may be, the metal member is advantageously preheated before being assembled to the support for bonding. In principle such preheating is intended to bring the metal member to a temperature close to that of the support when the latter is not at surrounding temperature. Of course, care will be taken to limit the temperature and heating time, so as not to affect the properties of the adhesive material. The advantage of this operation is a gain in time for the bonding, the result being a speeding up of the manufacturing tempo.

Said metal member is preferably assembled to the support by an inverting movement, the metal member having been supported by an adhesivefree surface. The advantage afforded by this embodiment of the process resides in the facility of stocking, transferring and handling the metal members whether or not already provided with an adhesive.

Advantageously, said metal member and support are pressed together during at least a part of the time in which said heating means is energised. The feature that a pressure is exerted during at least a part of the heating also produces superior connection of the metal member to the support. It also enables the air trapped between the metal member, the adhesive and the support to be at least partially eliminated and prevents the appearance of bubbles in the adhesive material.

This procedure is preferable to that in which the metal member and the adhesive material are heated after having been placed in position, a pressure being exerted subsequently, although this is not excluded by the invention. In practice, heating and pressure are initiated substantially simultaneously. Moreover, the pressure will preferably be maintained for a certain period of time after heating has ceased, to complete adhesion and prevent the appearance of bubbles.

The method according to the invention can particularly advantageously be used for attaching a driving mirror base to a motor vehicle windscreen which can be laminated or not. In the case of an unlaminated windscreen, as a rule the sheet of glass will be tempered. The bases consist, for example, of small metal members (2.7 x 2.1 x 0.6 cm) formed with grooves adapted to receive the driving mirror.

The invention also relates to an apparatus for gluing a metal member to a support, more particularly for the performance of the method disclosed hereinbefore.

In its most general aspect, the apparatus for gluing a metal member to a support is characterised in that it comprises a carrier for the support and a magnetic induction heating coil or loop so disposed adjacent the carrier that the support can be placed between the carrier and the coil or loop. This arrangement of the heating coil or loop greatly simplifies handling and does not appreciably narrow down the selection of the carrier for the support.

In a preferred embodiment the magnetic induction heating coil is borne by a member for locating the metal member to be glued. Preferably, the locating member is formed by a member comprising an aperture adapted to receive the metal member and a lateral inlet chute extending as far as such aperture.

To enable the support to be put in place on or by means of its carrier, the magnetic induction heating coil or loop can preferably move in relation to the carrier adapted to receive the support in a direction not parallel with the carrier. Moreover, to ensure effective bonding pressure, the apparatus preferably comprises a movable punch which engages in the aperture in the locating member for movement in the direction of the carrier adapted to receive the support. Advantageously, the movable punch can move independently of the member for locating the metal member. In an advantageous embodiment the movable punch has a supply duct for an adhesive material. This enables the adhesive material to be deposited at the place on the support where the metal member is to be attached.The duct enables the glue to be satisfactorily located on the support before the metal member is supplied, and obviates the need of providing a separate glue-locating member where the adhesive is not pre-applied to the metal member.

An advantageous optional feature of the invention is that a movable reaction punch is so disposed in line with the movable punch that when the support is deposited on the carrier, it can be placed between the movable punch and the reaction punch. This arrangement enables high bonding pressures to be applied without having to take into account the manner in which the support is carried. This feature is advantageous for apparatus intended for the treatment of non-flat supports, for example, bent sheets of glass which can be very satisfactorily supported by a carrier which bears against the support only at a few points and therefore does not provide an adequate reaction surface.

Preferably the apparatus comprises means for supplying a said metal member to said locating member and an extractor for extracting a said metal member from the supply means and transferring it to the locating member, which extractor comprises a finger with a retaining device which supports the metal member during its transfer to the locating member. In turn, the locating member preferably comprises retaining means allowing the passage of such metal member during its transfer to the locating member, but preventing the metal member from moving in the opposite direction when the extracting member is withdrawn. The retaining system can be formed by ball-and-spring stops, by arcuate tongs arms urged to closure or by a similar device.

The means for supplying the metal members preferably comprises an inverting device. In a particularly advantageous embodiment the inverting device is formed by an indexed wheel formed with peripheral notches adapted to receive metal members. Preferably, the supply device comprises means for introducing a metal member into a notch in the wheel from a supply chute. The supply chute can have a heating device for preheating the metal member. Advantageously the apparatus comprises means for synchronizing the movements of the members for extracting and introducing the metal members, so as to extract a member from a notch during the introduction of a member into another notch. Such synchronization can moreover extend over one or more notches.

Finally, to obtain a homogeneous mechanism which is simple to handle and does not interfere with the displacement of the supports on or by means of the carrier, advantageously the inverting device, the extracting and introduction members, the movable punch, the locating member and the magnetic induction heating coil are supported by the same assembly which can move in relation to the carrier adapted to receive the support in a direction not parallel with such carrier.

Advantageously the apparatus according to the invention can be used for gluing a metal driving mirror base on to a vehicle windscreen.

The invention also relates to the product obtained by the performance of the method and/or the apparatus according to the invention.

To illustrate the invention better, an apparatus will now be described which can be used according to the invention for one of its nonlimitative applications -- i.e., the gluing of driving mirror bases onto motor vehicle windscreens. The description is given with reference to the accompanying drawings, wherein:: Figure 1 is a section showing diagrammatically a pre-glued driving mirror base placed on an extractor, Figure 2 is a diagrammatic section of apparatus according to the invention, in cross-section across the centre of an indexed inverting wheel, Figure 3 is a diagrammatic view of the inverting wheel and also of a chute for supplying pre-glued metal members, and a preheating furnace, Figure 4 shows diagrammatically in crosssection the assembly formed by the inverting wheel, the extractor, a locating and induction heating member and punches for producing bonding pressure, and Figure 5 is a plan view showing the introduction of a base by an extractor into the inlet chute of the locating member.

In the drawings like elements have like references.

Figure 1 is a cross-section to an enlarged scale through a type of driving mirror metal base 1 bearing an adhesive material 2 on a substantially flat face which is to be bonded to a support. The preglued base is formed with longitudinal grooves 3 and projecting marginal ridges 4 which are turned inwardly and serve to retain a bracket of a driving mirror and are also used to retain the metal member during the various operations to which it is subjected for bonding to a support. In fact a typical base of this type measures about 2.7 x 2.1 x 0.6 cm, and the grooves open on one of the minor sides of the member. The drawing also shows diagrammatically an extractor 5 which carries the pre-glued base 1 The function of this extractor will be disclosed hereinafter.

Figure 2 is a diagrammatic overall view of a base-gluing apparatus in one embodiment of the invention. The apparatus is shown diagrammatically in the form of a cross-section taken through the centre of an inverting wheel.

Figure 2 shows a laminated support 11, in this case constituted by two glass sheets bonded together via an intervening thermoplastics layer to serve as a vehicle windscreen. The laminated structure is carried by an endless belt conveyor 12 and is held by an abutment 13 in a predetermined position for the bonding of a pre-glued metal base of the kind illustrated in Figure 1. Disposed above the laminated support 11 is a movable assembly which can be displaced in the direction of the carrier 12 by means of a jack 14 attached to a supporting framework. The assembly also comprises a U-shaped supporting portal 1 5 with unequal arms. The major arm of the U, in the lefthand part of the drawing, supports two jacks 16, 17 adapted to operate simultaneously by means of a connection 18 connected by the supply conduit for the driving fluid.The pusher of the jack 16 introduces into a notch 22 in the indexed inverting wheel 21 (described hereinafter) a preglued base arriving via an inlet chute 19, while the pusher of the jack 17 simultaneously extracts another pre-glued and inverted base which is then in a notch 22 at the bottom of the indexed wheel 21. The pusher of the jack 16 comprises simply a thrust element, but the pusher of the jack 1 7 comprises a finger 20 comprising a retaining device, for instance, a lug which supports the extracted metal member during its transfer. The section of the finger 20 is shown at 5 in Figure 1.

The minor arm of the U of the portal 5 which is, as already stated, displaceable by the action of a jack 14, supports the centre of the notched indexed wheel 21 and also a member having an opening 23 for locating the metal member to be bonded and a pressure punch 24 actuated by a jack 25 independent of the jack 14. A reaction punch 26 actuated by a jack 27 is shown at the bottom of the drawing, below the laminated support 11.

Figure 3 is a diagrammatic profile view of the inverting wheel 21 having notches 22 which is adapted to reverse the pre-glued metal members 1 supplied via the supply chute 1 9.The metal members are introduced into a notch 22 by a lateral pusher (reference 1 6 in Figure 2) and are extracted from the notch when it reaches the bottom of the wheel, by another lateral pusher shown in chain lines in Figure 3 (references 17 and 20 in Figure 2), whereafter the metal members are positioned over the opening 23 in the locating member with the pre-glued surface turned in the direction of the support 11, which in this instance forms part of a bent laminated structure. As already stated, the wheel 21 is retained at its centre by a pivot mounted on the minor arm of the U or the portal 15. As they pass through the inlet chute 19, the pre-glued metal members 1 are preferably preheated to a temperature close to that of the glass and compatible with the adhesive material used; such preheating is performed, for example, in an electric furnace 29 through which the inlet chute 1 9 extends.

Figure 4 is a cross-section through the assembly formed by the inverting wheel 21 with notches 22, the extractor finger 20, locating and heating means for the member, and the upper punch 24 lower punch 26 for exerting the pressure. The locating device is formed by a flat member 33 formed with an opening 23. It also has a lateral inlet chute 30 extending between the wheel 21 and the aperture 23. Heating is performed by a magnetic induction device whose loop or coil 31 encloses and is supported by the locating member 33.

In a preferred embodiment of the invention, the height of the magnetic induction coil or loop is substantially equal to that of the metal member to be glued. The coil is supplied by a thyristor inverter and a static frequency converter. The upper punch 24 is preferably formed with a central duct 32 for the supply of adhesive material in cases in which the metal members are not pre-glued. Of course the punches 24 and 26 are placed in line with one another, on either side of the support, but they are controlled by separate jacks (references 25 and 27 respectively in Figure 2) which may however be twinned. It should be recalled that the upper jack and corresponding punch form part of the assembly which can be displaced as a unit by the jack 14 (Figure 2). The ends of the punches 24 and 26 are made of a material which does not conduct electricity.

Figure 5 is a plan view of the device shown in Figure 4 at the upper level of the locating member, Figure 5 shows a driving mirror base 1 whose lower part is pre-glued and which is supported by the extractor finger 20.

The finger 20 moves the mirror base member in the direction indicated by the arrow towards the locating member. The latter comprises a flat member 33 formed with a lateral inlet tube 30 and an opening 23 adapted to receive and correctly locate the metal member to be glued on to the sheet of glass. It comprises a retaining system 34 formed, for example, by balls biased by springs. The function of this system is to allow the passage of the metal member during its transfer to the locating aperture 23, but to prevent the metal member from moving in the opposite direction when the extractor finger 20 is withdrawn.

The apparatus disclosed hereinbefore operates as follows: At first the jack 14 is in the raised position, so that the whole block supported by the portal 1 5 and comprising the device for inverting the metal members and the heating and pressure devices are removed from the path followed by the support. The jack 27 is in the lower position, so that the lower punch 26 does not interfere with the movement of the support.

The laminated support 1 l-comprising a sheet of glass (cf. Figure 2) leaving a preceding prebonding stage, is supplied and carried by the endless belt conveyor 12 under the bonding device with a view to receiving a metal base. The sheet is positioned by abutments 13, for example.

When the sheet is in place, the jack 14 lowers the block so that the locating member contacts the surface of the glass. A metal member which is to be glued, and which has possibly been pre-glued in a preceding phase and preferably preheated at the place 29, is pushed by the jack 1 6 out of the supply chute 1 9 into a notch 22 in the inverting wheel 21. At the same time, as a result of the connection 1 8 between the jacks 1 6 and 17, the metal member in the notch 22 at the bottom of the indexed wheel 21 is taken by the finger 20 of the extractor with the retaining device and is transferred along the chute 30 until in line with the aperture 23 in the locating member 33. The finger then withdraws and the metal member 1 is retained by the devices 34.When the metal member is released from the finger 20, the member drops to the bottom of the aperture 23 on to the support. At that moment the heating device 31 is put into operation and the pressure punch 24 is lowered, while the reaction punch 26 is raised, each by their respective jacks 25 and 27.

After the brief heating and pressure time has elapsed, the latter possibly being longer than the former, the punches are withdrawn by an opposite movement of the jacks 25 and 27. The jack 14 then lifts the whole operational block which it supports. When the jack 14 is in the top position, the wheel 21 is so indexed by a ratchet that another notch 22 containing a metal member comes into register with the chute 30 of the locating member. In the upper part of the wheel an empty notch 22 will take up its place opposite the pusher of the jack 1 6, so as to be ready to receive a fresh member from the supply chute 1 9. At the same time the abutments 13 are lowered and the sheet of glass 11 is moved on by the conveyor 12 to a subsequent manufacturing stage, consisting in final bonding in an autoclave.Another support can take the place of the preceding one, and the cycle of operations starts all over again.

A number of examples will now be given of the method and use of the apparatus which will emphasize the advantages afforded by the invention.

EXAMPLE 1 A "ZAMAK" (Trade Mark) driving mirror base having the aforementioned dimensions of 2.7 x 2.1 x 0.6 cm, to which was pre-applied a 2.5 x 2 cm polyvinyl butyral film 0.38 mm in thickness, was bonded to a motor vehicle windscreen by means of the apparatus disclosed hereinbefore. When the pre-bonded laminated windscreen arrived from the pre-bonding station it had a temperature of about 550C. The base was preheated to about 500C and was brought to the bonding point in the manner disclosed. The induction heating lasted for 3 seconds, while at the same time a pressure of the order of several bars was applied, this being continued for 1-4 seconds after heating had ceased. The induction frequency was 20-25 kHz. The power of the supply to the induction coil was or the order of 4 kW.The assembly was then withdrawn from the apparatus by the conveyor belt and fed to an autoclave, in which the windscreen and base were subjected to firm bonding conditions at an approximate temperature of 120-1 300C.

By way of comparison, according to US Patent No. 3 242 026, a driving mirror support was bonded on to a sheet of glass by magnetic induction heating at a frequency of 450 kHz for 7-10 seconds, the power consumption being 50 kW. In this case the induction bobbin was placed on the side of the sheet of glass remote from the location of the metal member and adhesive material.

The same conditions were adopted for gluing a steel base of 2.7 x 2.1 x 0.8 cm.

EXAMPLE 2 A metal base identical with that in Example 1 was to be glued, but this time to a laminated windscreen which had already been finally bonded. Use was made of the same bonding apparatus and bases pre-covered with a Minnestoa "AF42" adhesive film. A heating time of 34 seconds was used, pressure being exerted for 25-30 seconds. The power supplied was 4 kW. The same result was obtained in the same conditions with a polyvinyl butyral film 0.38 mm in thickness, without transfer of the assembly to an autoclave.

EXAMPLE 3 A metal base was bonded by the apparatus disclosed to an already bonded windscreen, this time using a base free from adhesive material. The adhesive material was deposited on the surface of' the glass via an adhesive-supplying duct 32 (shown in chain lines in Figure 4) before the base was introduced into the aperture 23 in the locating member. The order of operations was as follows: arrival of the windscreen ascent of the lower punch descent of the upper carrying assembly supply of adhesive positioning of the base descent of the upper punch, and pressing for 10 seconds and heating.

The power supplied was 4 kW during heating.

The adhesive material used was a cyanoacrylate resin which is commercially available under the Trade Mark "LOCTITE".

Claims (25)

1. A method of bonding a metal member to a non-metallic structural support in which the metal member is assembled to the support and is bonded thereto by a body of adhesive material using a process which involves heating, characterised in that such heating is effected using magnetic induction heating means comprising a coil or loop which is disposed adjacent the metal member and of which at least a portion lies on the same side of the metal/adhesive interface as the metal member.

2. A method according to Claim 1, characterised in that said support comprises a vitreous sheet.

3. A method according to Claim 2, characterised in that said support is a laminated support comprising at least one vitreous sheet and at least one plastics sheet.

4. A method according to any preceding claim, characterised in that said bonding between the metal member and the support is effected by a body of adhesive material intervening between them which adhesive material is preferably constituted by a thermoplastics film, and is optionally preapplied to said metal member.

5. A method according to Claim 3, characterised in that bonding of said laminated support is effected in two stages, namely a prebonding stage and a firm bonding stage, and in that said metal member is bonded to the support between said prebonding and firm bonding stages.

6. A method according to any preceding claim, characterised in that said loop or at least some turns of said coil surround the metal member to heat it.

7. A method according to Claim 6, characterised in that the height of said coil or loop is substantially equal to the height of said metal member from the support.

8. A method according to any preceding claim, characterised in that said metal member is heated before being assembled to the support for bonding thereto.

9. A method according to any preceding claim, characterised in that said metal member is assembled to the support by an inverting movement, the metal member having been supported by an adhesive-free surface.

10. A method according to any preceding claim, characterised in that said metal member and support are pressed together during at least a part of the time in which said heating means is energised.

11. A method according to any preceding claim, characterised in that said metal member is constituted as a mirror bracket and said support is constituted as a vehicle windscreen.

12. Apparatus for performing a method according to any preceding claim, characterised if l that it comprises a carrier for the support and a magnetic induction heating coil or loop so disposed adjacent the carrier that the support can be placed between the carrier and the coil or loop.

13. Apparatus according to Claim 12, characterised in that the magnetic induction heating coil is borne by a locating member comprising an aperture adapted to receive the metal member and a lateral inlet chute extending as far as such aperture.

14. Apparatus according to Claim 13, characterised in that it comprises a movable punch which engages in the aperture in the locating member for movement in the direction of the carrier adapted to receive the support.

1 5. Apparatus according to Claim 14, characterised in that the movable punch has a supply duct for an adhesive material.

1 6. Apparatus according to Claim 14 or 15, characterised in that a movable reaction punch is so disposed in line with the movable punch that when the support is deposited on the carrier, it can be placed between the movable punch and the reaction punch.

1 7. Apparatus according to one of Claims 1 3 to 1 6, characterised in that it comprises a means for supplying a said metal member to said locating member and an extractor for extracting a said metal member from the supply means and transferring it to the locating member, which extractor comprises a finger with a retaining device which supports the metal member during its transfer to the locating member.

1 8. Apparatus according to Claim 17, characterised in that the locating member comprises retaining means allowing the passage of such metal member during its transfer to the locating member, but preventing the metal member from moving in the opposite direction when the extracting member is withdrawn.

1 9. Apparatus according to Claim 1 7 or 18, characterised in that the metal member supplying means comprises an inverting device formed by an indexed wheel formed with peripheral notches adapted to receive metal members.

20. Apparatus according to Claim 19, characterised in that it comprises means for introducing a metal member into a notch in the wheel from a supply chute.

21. Apparatus according to Claim 20, characterised in that it comprises means for synchronizing the movements of the members for extracting and introducing the metal members, so as to extract a member from a notch during the introduction of a member into another notch.

22. Apparatus according to Claim 12 and substantially as herein described.

23. A method according to Claim 1 and substantially as herein described.

24. A non-metallic structural support having a metal member bonded thereto by a method according to any of Claims 1 to 11 and 23 optionally using apparatus according to any of Claims 12 to 22.

25. An article according to Claim 24, characterised in that said support and metal member are respectively constituted as a windscreen and a mirror base.