GB2123506A

GB2123506A - Insert for panels

Info

Publication number: GB2123506A
Application number: GB08219187A
Authority: GB
Inventors: Victor Deron
Original assignee: Societe des Telephones Ericsson SA
Current assignee: Societe des Telephones Ericsson SA
Priority date: 1982-07-02
Filing date: 1982-07-02
Publication date: 1984-02-01
Also published as: GB2123506B

Abstract

A panel has an insert which may be of plastics or metal comprising a central part framed by two collars (10, 11) coaxial of the central part and engaging opposite surfaces of the panel (12). One of the collars may be integral with the central part as shown in Fig. 4. One collar, or two collars in the case illustrated, in Fig. 1 is adapted to nest with the central part, the same having provision (13, 17) such as a screw-threaded or other aperture for connection to an external element. The collars are stuck to the surfaces of the panel and to the central part by adhesive. A number of inserts can be provided either to extend through the panel body or to be fitted to the panel edge; in the latter case the inserts have a straight edge (Fig. 4). In order to keep the elements 10, 20 (Fig. 4) together until the adhesive has set a tubular extension 22 of the body 20 is arranged to extend through an aperture in the collar 10, and is then crimped over. A suitable tool is disclosed for this purpose (Fig. 6, not shown). A similar tool is also disclosed for holding the elements together during setting when no crimping is involved. <IMAGE>

Description

SPECIFICATION Panel assembly element This invention relates to panel assembly elements hereinafter referred to as inserts and which are adapted to be secured permanently to a panel and to have connecting means enabling another constructional element to be joined up.

Many inserts for this purpose are known; they have to be used whenever it is required to assemble lightweight or delicate panels unsuitable for direct connections. Elements of this kind, or "inserts" are often used inter alia in aeronautical and space engineering, for instance, for the assembly of honeycomb panels.

It is the object of this invention to provide an insert which behaves better in practice than the prior art inserts, inter alia because it can be used on the edge of a panel as well as in its body, because a lightweight insert can provide adequate rigidity and the insert can be fitted as readily after the production of a panel as during its production.

Accordingly the invention proposes inter alia an insert, characterised in that it comprises a central part framed by two collars coaxial of the central part and adapted to engage opposite surfaces of the panel and to be secured to such surfaces by sticking, at least one collar being nestable in the central part and adapted to be stuck thereto, the central part having means for connection to an external element.

The connecting means can often be no more than a single and possibly screwthreaded aperture which extend along the axis or across the same or even obliquely. The insert has a symmetry of revolution and, in the case of being fitted to the panel edge, is truncated in a plane parallel to the axis. The surfaces adapted to co-operate by nesting are usually truncoconical, with an inclination which is usually approximately 10%.

It may often be desirable for the central part to be formed with an aperture through which adhesive can be introduced between the insert and the panel.

The material of which the insert is made can be chosen to suit the intended use. A light alloy is very often used, particularly in aeronautical engineering. In other cases titanium and the alloy Invar may be used to connect honeycomb panels in aerospace engineering and more generally in all cases where there are problems of differential expansion. Plastics can be used instead of metal in cases in which the forces to be transmitted are always slight.

The invention also relates to a process and a tool for assembly of the insert, both with the advantage of being simple and highly versatile in their use.

The invention will be more clearly understood from the following description of embodiments of the invention given by way of non-limitative example, reference being made to the accompanying drawings wherein: Figures 1 and 2 are diagrammatic views showing, in section along the axis and looking down on to Figure 1, respectively, two inserts in accordance with one embodiment of the invention in position on a panel; Figure 3 is a perspective view showing one possible construction of the elements shown in Figures 1 and 2; Figure 4 is a view similar to Figure 3 of a variant; Figure 5 is a theoretical diagram showing the insert of Figure 4 after positioning but before final securing, the view being in section on a plane passing through the axis; and Figure 6 is a partly sectioned elevation of a tool for the panel edge assembly and securing of an insert of the kind shown in Figure 5.

The assembly element or insert can in all cases be considered as comprising a central part framed by two collars 10, 11, the whole having a symmetry of revolution. When the element is in position, the edges of the two collars 10, 11 are applied to opposite surfaces of a panel 12 and stuck to such surfaces.

As Figures 1 and 2 show, the insert can be positioned either so as to extend through the body of a panel 12, in which case the insert is entire, or as to be edge-mounted on the panel, in which case the insert is usually sectioned in a plane such that at least half the insert remains. The central portion has securing means which take the form just of a single and possibly screwthreaded aperture in the embodiment of Figures 1 and 2. If edge mounted on the panel, the insert is formed with a radial blind bore 1 3 adapted to receive a screw 1 5 for securing a transverse and e.g.

honeycomb panel 1 6. An insert which extends through the panel body is formed with an axial assembly aperture 17. These forms of connection are not the only ones possible and, more particularly, oblique assemblies are possible.

In all cases at least one of the two collars is separate from the body and is adapted to be nested and stuck therein. However in the embodiment shown in Figures 1 to 3 the insert comprises three parts - the two collars 10, 11 and a central part 1 8. The latter takes the form of a solid central pin or stud or the like extended by two skirts which before positioning have an outside surface which is cylindrical and which extends that of the pin, the skirts having an internal truncoconical surface with an inclination which is usually of approximately 10%. Each of the two collars, which are symmetrical in the case shown, is embodied by a thin skirt with an outside truncoconical surface, and an edge.Of course, the dimensions of the collar skirts are such as to permit them being nested in the skirts of the central part 18, the collar edges contacting the opposite surfaces of the panel 12 before the end of the skirts abuts the pin. It may often be advantageous if the thickness of the insert edges decreases radially from the centre towards the periphery, in the manner shown in Figure 1.

The constituent elements of the insert are adapted to be interconnected by sticking. As a rule, a cold adhesive which polymerizes in a few hours is used, the choice depending upon the operational environment of the assembled system.

As a rule, the adhesive is placed on at least one of the surfaces to be assembled before nesting. More particularly, the edges of the collars 10, 11 are coated with adhesive before being positioned so as to stick to the opposite surfaces of the panel 12. Also, the skirts are stuck by means of an adhesive with which at least one of the skirts is coated before nesting. The thickness of the adhesive on the finished assembly is, as a rule, of the order of 0.05 mm. A greater thickness can be provided before positioning, the excess adhesive being removed by the pressure operative during polymerisation.

An insert in accordance with the invention can be fitted in an aperture in a straight part of a panel, as shown in the right-hand part of Figures 1 and 2, or in an aperture in the panel edge, as shown in the left-hand part of Figure 1. It is advantageous to be able to edge mount an insert sectioned along a plane parallel to its axis since a panel can be produced without foreknowledge of the position where it will have to be cut to form an edge.

However, complete inserts can be positioned first of all, whereafter the system formed by the panel and the inserts can be sectioned along an appropriate iine, subject to at least half of each of the section inserts remaining.

Once the collars have been stuck to the panel surfaces and to the skirts, adhesive can be injected to connect the central part of the insert to the interior of the panel. Accordingly, one or more adhesive injection channels can be provided, such as the channels 1 9 shown diagrammatically in Figure 1.

An ancillary tool, of a kind to be described hereinafter, is necessary to keep the inserts shown in Figures 1-3 pressed together during sticking.

Such a tool is unnecessary if the central part of the insert and the collars or central part thereof which it is required to join by nesting and sticking are provided with securing means while the adhesive is polymerising.

In the embodiments shown in Figures 4 and 5 in which like elements have the same references as in Figures 1-3, the insert is in two parts, embodied by a collar 10 and an integral core 20, the latter corresponding to the central part and second collar of the embodiment of Figure 1.

The collar 10 and the core of body 20 have co-operating crimping or staking means or the like enabling them to be kept assembled while the adhesive polymerises but insufficient to withstand the stresses arising when the assembled panel is in use. Such means comprise a cross-wall 21 of the collar 10, the wall being pierced with a central aperture, and a tubular extension 22 of the core.

When first the body 20, then the collar 10, are positioned, the edges having been coated with adhesive, the skirt of the collar 10 nests in the body 20 (whose side wall of revolution acts in the same way as the skirt of Figure 1 except that it is positioned radially inwards and not radially outwards of the collar skirt). The tubular extension 22 is long enough to project through the aperture in the cross-wall 21 (Figure 5). It is thin enough to be bent on to the cross-wall 21 to form a crimping or staking to keep the collar 10 and the body 20 assembled during the time it takes for the adhesive coating the edge surfaces in contact with the panel 12 and the inside surface of the collar skirt to polymerise. An aperture 23 can be present through which adhesive can be injected between the insert and the core of the panel 12.

The element shown in Figures 4 and 5 is sectioned so as to be fitted to a panel edge.

However, an insert could be fitted similarly to a straight part of a panel.

Different kinds of tool can be used to crimp or stake the integers 20 and 10 together. The tool shown by way of example in Figure 6 is adapted to secure inserts of the kind shown in Figures 4 and 5 to the edge of a panel 1 2. The tool comprises a stirrup 24 having a handle 25, the stirrup arms being pierced with two coaxial apertures. One such aperture is adapted to receive a bearing pin or spindle 26 releasably secured by a screw 27.

The other aperture has a tapped lining 28 in which a pressing element, in the form of a screw having an actuating head 30, can move. Element 29 also has a shoe or pad or the like 31 adapted to engage the edge of the collar 10 and rotatable relatively to the screw 29, being so secured thereto by a pin 32 as to be displaceable together with screw 29.

The screw 29 is hollow. Extending through it is a crimping or staking element 33, in the form of a screw movable in a tapped aperture in screw 29.

Screw 33 projects from shoe or pad 31 to abut the tubular extension 22 of the body or core 20 of the insert.

In the embodiment shown in Figure 6, the tool also has a wedge 34 which is secured releasably by a screw 35 and whose thickness depends on the thickness of the panel 12 to which the insert is to be fitted, wedge 34 limiting movement of pad or shoe 31 towards the integer 26.

The operation of the tool is clearly apparent from the foregoing description and will therefore be no more than outlined. After the body 20 and collar 10 of an insert have been positioned by hand, the tool is placed over them. The two parts of the insert are moved together by means of the screw 29. Contacting the wedge 34 prevents the panel from being crushed while maintaining the edges in sufficientiy firm engagement with the opposite surfaces to ensure satisfactory sticking of the edges and of the conical parts. The two parts are then crimped to one another by depressing the screw 33. The tool can be withdrawn after crimping. The crimping then maintains the pressure for the time it takes for the adhesive to polymerise.

Any constructional variants of the invention are of course possible, more particularly with regard to the exact shape of the constituent elements of the insert, for instance, to facilitate series production. Also, a tool similar to the tool shown in Figure 6 can be provided which can keep the constituent parts of the assembly pressed together for the time required for sticking when there is no crimping.

Claims

1. A panel assembly element, or insert, characterised in that it comprises a central part framed by two collars coaxial of the central part and adapted to engage opposite surfaces of the panel and to be secured to such surfaces by sticking, at least one collar being nestable in the central part and adapted to be stuck thereto, the central part having means for connection to an external element.

2. An insert according to Claim 1, characterised in that either each collar or the nestable collar has a radial edge and a skirt, the latter being nestable in a correspondingly shaped skirt which prolongs a solid pin belonging to the central part.

3. An insert according to Claim 2, characterised in that the facing surfaces of the skirts are truncoconical.

4. An insert according to Claim 1,2 or 3, characterised in that it is sectioned in a plane which is parallel to its axis or oblique and which usually coincides with the panel edge in the case of assembly on the panel edge.

5. An insert according to any of the previous claims, characterised in that the central part is pierced with passages for the introduction of adhesive between the insert and the panel.

6. An insert according to any of the previous claims, characterised in that either each collar or the nestable collar co-operates with the central part through the agency of crimping means.

7. An insert according to any of the previous claims, characterised in that it is made of light alloy or titanium or a low heat expansion alloy, such as Invar, or plastics.

8. An insert according to Claim 2 or any claim appended thereto, characterised in that the thickness of every edge decreases from the centre towards the periphery.

9. A process according to Claim 8 characterised in that the or each collar nested in the central part is secured by crimping by the flaring above a cross-wall of the collar of a tubular extension of the central part, such extension extending through an aperture in the cross-wall.

9. Inserts substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.

10. A process for assembling a panel, characterised in that a central part of an insert and two collars are introduced into an aperture in the panel, each such collar having an edge and at least one such collar being nestable in the central part while the other can be either nestable therein or integral therewith, so that the two edges engage flush with the opposite surfaces of the panel whereafter the edges are stuck to the opposite panel surfaces and the central part is stuck to the or each collar.

11. A process according to Claim 10 characterised in that the or each collar nested in the central part is secured by crimping by the flaring above a cross-wall of the collar of a tubular extension of the central part, such extension extending through an aperture in the cross-wall.

12. A tool for use in the process according to Claim 11, characterised in that it comprises a stirrup having a bearing spindle engageable with the collar body, a pressing element movable away from and towards the spindle as far as a distance therefrom determined by a replaceable shim, and a crimping element which is movable in the spindle and coaxial thereof and can bear on the tubular extension to flare the same.

1 3. A tool substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.

New claims or amendments to claims filed on July 29th 1983 Superseded claims: All New or amended claims:

1. An insert, comprising a central part framed by two collars coaxial of the central part and adapted in use to engage opposite surfaces of a panel and to be secured to such surfaces by sticking, at least one collar being nestable in the central part and adapted to be stuck thereto, the central part having means for connection to an external element said insert being sectioned in a plane parallel to its axis or oblique to its axis, said plane substantially coinciding with an edge of the panel, said central part having means for connection of an external element against said edge.

2. An insert as claimed in Claim 1, wherein either each collar or the nestable collar has a radial flange and a skirt, the latter being nestable in a correspondingly shaped skirt which is an extension of a solid central part.

4. The insert as claimed in any one of the previous claims, wherein the central part is pierced with passages for the introduction of adhesive between the insert and the panel.

5. The insert as claimed in any one of the previous claims, wherein either each collar or the nestable collar co-operates with the central part through the agency of crimping means.

6. The insert as claimed in any one of the previous claims, wherein it is made of light alloy or titanium or a low heat expansion alloy, or a plastic material.

7. Inserts substantially as hereinbefore described with reference to, and as shown in, the figures of the accompanying drawings.

8. A process for assembling a panel, characterised in that a central part of an insert and two collars are introduced into an aperture in the panel, each such collar having a flange and at least one such collar being nestable in the central part while the other can be either nestable therein or integral therewith, so that the two flanges engage flush with the opposite surfaces of the panel whereafter the flanges are stuck to the opposite panel surfaces and the central part is stuck to the or each collar.