DEVICE FOR SECURING AN OVERLAP ADHESIVE JOINT

Abstract: Device for securing an overlap adhesive joint between two workpieces, in the form of vehicle body panel parts, particularly a joggled joint comprising a bridge element (11) adapted at its first end (21) to enable supporting engagement against the surface of the first workpiece (1) at a distance from the joint (5, 7, 9) and adapted at its second end (22, 23) to enable the achievement of joint-securing pressure against the surface of the second overlapping workpiece (3) in the region of the joint; an attachment plate (13) adapted such as to enable its being held by an adhesive joint (29) on said surface of the first workpiece in the region between the joint and the location of engagement of said first end against the surface of the first workpiece; and means (15, 17) for lockably connecting and tightening the bridge element (11) and attachment plate (13) such as to press the bridge element, applied for securing the joint, against the workpieces with said first end (21) engaging against the first workpiece (1) and said second end (22, 23) achieving securing pressure on the joint (5, 7, 9) determined by the amount of tightening.

Description: TITLE OF INVENTION Device for securing an overlap adhesive joint . < TECHNICAL FIELD " 5 The present invention relates to a device for securing an overlap adhesive joint between two workpieces, particular¬ ly a joggled joint . The device in accordance with the invent¬ ion is intended for use in conjunction with joining vehicle body panel parts, particularly in conjunction with the 10 fastening of so-called economy panel parts. TECHNICAL BACKGROUND There is a great amount of rust and damage repairs to vehicle bodies. The kind of activity envisaged here is, for 15 example, the repair of panel edges that have rusted away or the repair of collision and similar damage, in which so-call¬ ed economy panel parts are utilized. Up to now, these economy panel part's have usually been put in place with the aid of welding. Welding requires spe- 20 cial equipment, extensive dismantling of combustible material and causes difficulties with respect to protection against later rust attack. Economy panel parts have also been put in place while utlizing riveted and/or screwed joints, these methods being 25 complex and from many aspects giving poorer joint properties, howeve . More recently it has been proposed that body panel parts could be joined together using an adhesive joint. In order that an adhesive joint shall be sufficiently good there 30 is required a uniform and well-adjusted compression of the . joint while the adhesive sets. In certain cases, such com¬ pression can be provided by different kinds of cramps, namely when the joint is accessible from both sides. However, the latter is often not the case, particularly when joggled 35 joints are involved, where only one side is accessible, this side generally being the outside of the body panel. In these cases a complicated fixture system has been used, which is applied with the aid of vacuum cups and which has a large number of jacking screws, which are first positionally ad¬ justed along a carrying frame and are then tightened alterna- tingly such as to give uniform pressure loading on the adhe¬ sive joint. This method of securing the joint is expensive, time-consuming and difficult to utilize. From US A 2,379,136 there is previously known a secur¬ ing device intended for securing two overlapping panel edge portions in conjunction with joining said portions by weld¬ ing. This known device consists of a T-shaped rigid element having a fixed electro-magnet at the lower end of its post for holding the element against a first panel part and having a jack screw at each of the free ends of the cross arm locat- ed on the top of the post, each jack screw extending parallel to the post and being in threaded engagagement with said ends. One of the jack screws is intended for being tightened into 'engagement with said first panel part having the elec- - tro-magnet applied thereon. The other jack screw is intended for being tightened into engagement with the other panel part so as to give the desired clamping effect. This known device lacks versatility and is difficult to apply so as to give a desired well balanced clamping or compressing effect. It is not suitable for securing an overlap adhesive joint between thin vehicle body panel parts. OBJECT OF THE INVENTION The object of the present invention is to provide a simple securing device for overlap adhesive joints, the de- vice being simple, cheap, easy to apply and handle, as well as being extremely adoptable and adjustable, i.e. it has the character of an uncomplicated, easily handled and cheap tool with the obvious advantages pertaining thereto. SUMMARY OF THE INVENTION The above-mentioned object is achieved with a device which, in accordance with the invention, has the distinguish- i ing features disclosed in the accompanying claims. The inventive device is thus essentially distinguished in that it includes a bridge element, one.end of which is adapted such as to enable supporting engagement at a distance from the joint against the surface of the first workpiece, its other end being adapted for enabling the achievement of joint securing pressure in the region of the joint against the surface facing towards the device of the second overlap¬ ping workpiece;. an attachment plate arranged for enabling removable- attachment, with the aid of an adhesive joint, to said surface of the first workpiece in the region between the joint and the position of engagement of said first end against the surface of the first workpiece; and means for lockably connecting and tighten the bridge element and the attachment plate to "urge the bridge element applied for se- * curing purpose against the workpieces with said first end engaging against the first workpiece and said second end achieving securing pressure on the joint determined by the amount of tightening. The term "bridge element" is intended to have a wide sense in the present context, and is intended * to cover any element enabling two spaced points of support or contact facing generally in the same direction and having therebetween an intermediate attachment plate and associated connection means. In utilising a device in accordance with the invention, it may be mounted substantially over the first workpiece, because only an end portion of it needs to be situated above, and act on, the joint part of the second workpiece. As will be understood, this signifies that the second workpiece does not need to have any great free extension at the joint it¬ self, and may, for instance, merely have a small free edge region (which thus constitutes the joint region) against which the device may be applied. It is advantageous to apply the device with its longi¬ tudinal direction substantially transverse the longitudinal direction of the joint. In this way the load on said first workpiece will be as favourable as possible, i.e. it will be spaced clear of the joint. It will be understood that the device is suitably elongate and narrow (several devices can then be easily mounted parallel to each other or side by side at suitable mutual spacings), although other con igurations are of course conceivable. Of essential importance for the versatility and adapt¬ ability of the device is that the bridge element and said connection means are adjustable relative each other. Prefer¬ ably said connection means are displaceable along the bridge element in its longitudinal direction, at least to a limited extent, and the bridge element is rotatable about the con¬ nection means in each displaced position. There is thus en¬ sured maximum adjustability of the bridge element even after the attachment plate has.been attached to said first work- piece, and the position of the connection means has been es- tablished. Furthermore, it is preferred that the bridge element and said connection means are adjustable relative each other such that the bridge element is swingable or tiltable relati¬ ve said connection means generally in a main plane for the bridge element, at least to a limited extent. This will give an additional possibility of adaption to various levels or inclinations of the places where the bridge element is to engage the plates. It will thus be understood that the selection of the location where the attachment plate is adhered is not at all critical for the good function of the device, while any kind of adjustment of the bridge element position and thereby the position of the securing pressure exercised on the joint will be possible, both during fitting-up and afterwards. The attachment plate is given an area such that on its being loaded there is no deformation of the coacting work- piece, even if this is a thin vehicle body panel, and such that the tensional stress in a direction away from the work- piece caused by the tightening of the device, can be taken up to a required extent. However, the bond of the attachment plate can be suited so that the plate ' will be released if an attempt is made to tighten the device too much, which could give deformation in the joint. For attaching the attachment plate, suitably an adhe¬ sive agent is used which has a substantially lower resistance to peeling or shearing than to pure tensional force away from the attachment surface on the workpiece. Thus, after use the attachment plate can be easily removed by peeling off or shearing, without the workpiece being damaged. Adhesion of the attachment plate can be effected to advantage with the use of double-sized adhesive tape, which can easily be applied to the bottom of the attachment plate each time it is used. It is -to be emphasized that the utilisation of an at¬ tachment plate adhered in accordance with the invention sig- nifies that the workpieces only need to be prepared minimally before applying the device. All that is required is that the surface of the first workpiece is cleaned (even this might not be necessary) sufficiently for the adhesive to take. The securing pressure on the joint can be achieved by the end of the bridge element engaging directly against the joint, or via a separate intermediate press element. In the latter case there will be further adjustment and force dis¬ tribution possibilities, since the position of the press ele¬ ment under the urging bridge element will be freely select- able. The press element is suitably made elongate and placed along the joint transverse the bridge element, whereby the pressure from the bridge element can be distributed along the joint in accordance with the number of joint engagement lo¬ cations exhibited by the press element. The invention will now be described in more detal with the aid of an exemplifying embodiment and with reference to the accompanying drawing. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic side view of a device in accord¬ ance with the invention applied for securing a joggled adhe- sive joint between two vehicle body panel parts. Fig. 2 is a schematic view from above of the device in Fig. 1. Fig. 3 is a schematic side view of the device in Fig. 1 supplemented by a press element and applied for securing an- other joggled adhesive joint between two body panel parts. Fig. 4 is a schematic view from above of the device applied according to Fig. 3. Fig. 5 is a schematic partial view from above of an elongate joggled adhesive joint, secured by utilising a plu- rality of devices in accordance with the invention. DESCRIPTION OF EMBODIMENTS • • . Figs. 1 - 5 illustrate joining, while using a device- according to the invention, two panel parts, either 1 and 3 or 2 and 4, the parts being substantially flat at the joint itself * in the illustrated embodiments and which may be inclu¬ ded in a vehicle body, for instance. .The first panel part 1 or 2 is thus a part of the body proper, while the other panel part 3 or 4 is an economy panel part for replacing a part of a body panel damaged by rust. The respective joint is a jogg¬ led joint, the edge area of the part 1 or 2 being joggled to form a continuous flat flange or step 5 against which the edge portion 7 of the part 3 or 4 is adhered with a thin ad¬ hesive layer 9 brushed on in the form of a covering film. The step, which can be achieved in a manner known per se with a joggling tool, corresponds to the thickness of the part 3 or 4 plus the thickness of the adhesive layer, so that the out¬ side of the part 3 or 4 will be flush with the outside of the part 1 or 2 at the joint. The width of the joggled part or flange 5 is typically, about 20 mm. The thickness of the ad¬ hesive layer 9 is typically 150 to 200 ym. The adhesive is a 2-component polyurethane adhesive which sets already at about 20°C. The thickness of the panel sheet is typically about 1 mm. One or more devices in accordance with the invention are utilized for compressing the joint while the adhesive sets. Such a device includes a bridge element 11, an attach- * ent plate 13 and connection means 15, 17. The bridge element 11 is a straight beam element and comprises two spaced, mutu¬ ally parallel flats 19,20 on edge, with downwardly, dependent end elements 21,22, also of flats, at either end. The end elements 21,22 are welded to the flats 19,20, thus forming a rigid connection thereof. The end elements 21,22 are at right angles to the plane of the flats 19,20. The end elements 21,- 22 are of the same length and are downwardly cut square to give the best engagement surface. There is an extension ele¬ ment 23 downwardly on the end element 22, this also being in the form of a straight flat fastened parallel to the element 22 and rotatably with the aid of a journalling pin 25. The element 23 is mounted with unequal distances to its ends so that two different extension lengths can be obtained. The mounting is also situated sufficiently high up on the end element 22 so that the element 23 is entirely above the lower engagement surface of the end element 22 after being rotated 90° (see Fig. 3) . The attachment plate 13 is a flat disc, and on its un¬ derside it is provided with double-sized adhesive tape 29 for attaching the plate to the panel part 1 or 2. There is a threaded rod 15 projecting at right angles to the attachment plate, the length of the rod being such that it passes be- tween and projects beyond the opposite sides of the flats 19,20. The diameter of the rod 15 is somewhat less than the spacing of the flats 19,20. A wing nut 17 is threaded on to the rod 15 and together they form means for connecting the attachment plate 13 and bridge element 11. When the device according to Figs. 1 and 2 is applied, the attachment plate 13 is attached at a suitable distance from the adhesive joint 5,7,9. If not already loosely mounted on the rod 15, the bridge element 11 is now fitted and the wing nut 17 loosely threaded on. As will be understood, the bridge element 11 may now be readily both displaced and rota- ted relative the now fixed rod 15 so that the bridge element end 22,23 can be suitably placed above the joint. Use of the extension element 23 in one of its extension positions is depicted in Fig. 2, for providing securing pressure to the joint. It will be easily understood that this pressure can readily be regulated by tightening the wing nut 17 to a grea¬ ter or lesser extent. It will be further understood that if the panel part 1 did not have the joggle or step 30, it would not have been necessary to utilize the extension element 23. In such a case the end element 22 could have abutted directly against the panel part 7. It has been found that securing a joint with the utili¬ sation of a device in accordance with the invention gives very good static loading, which is uni ormly ' distributed and does not give rise to injurious bending or peeling forces. On the contrary there is obtained a tendency for the respective panel edges to be deflected inwards towards the respective abutting panel, as is indicatd by arrows 31,33 in Fig. 1, which advantageously contributes to provide a homogeneous and resistent joint. It has further been found that applying the attachment plate comparatively close to the joint results in an upwardly directed counter force on the plate in question, which fa¬ vourably counteracts the downward force on the joint itself, whereby the contour of the panel in the region of the joint is retained. In other words, securing the joint in this way does not give rise to an inward deflection or deformation in the vicinity of the joint. It should be emphasized that the device according to the invention can have a low configuration. This is of impor- tance when applying the device on vertrical panel parts (this often being the case in conjunction with vehicle body pa- nels), because then the centre of gravity of the device will lie close to the panel parts which means that the bending moment on the attachment plate caused by the force of gravity will be low. A variation of the device in accordance with the inven¬ tion is illustrated in Figs. 3 and 4, a separate press ele¬ ment 35 being utilized for transferring the compressive force from the bridge element 11 to the joint. This separate ele¬ ment 35 is a straight, square hollow tube, which is placed under the compressive end of the beam elements 19,20 at right angles to the longitudinal direction of the bridge element 11. The element 35 is provided at either end with two abutt- ment surfaces 37,38 on its underside. It will be understood that the element 35 may easily be given a desired location relative the bridge element 11, thereby achieving a desired distribution and spread of the securing pressure. As will be seen in Fig. 3, the elements 22 and 23 have no function in this case, and they could thus be eliminated. Finally in Fig. 5, there is schematically illustrated how a plurality of devices in accordance with the invention can be used for securing a long adhesive joint of the kind already illustrated. Furthest to the right where the joint begins, there s utilized a device in the way illustrated in Fig. 1. The devices successive to it are utlized in the way illustrated in Fig. 3. It will be understood that even if all the devices in Fig. 5 are illustrated as being applied at right angles to the longitudinal direction of the joint they could have some other angle if so desired, e.g. due to pro¬ jecting obstacles, lack of space for attaching the plate 13 etc . It will be understood that a device in accordance with the invention is extremely simple to handle, apply and ad¬ just; that it has an uncomplicated structure which is cheap and which can be readily dimensioned for different loads; that it can be used without the workpieces involved being subjected to any deformations or other damage; that it is cheap and requires a minimum of consumption material (only adhesive); that it does not require any external power supply at all, or any other extraneous aids, such as welding, pop rivets, screws etc; that as a result of its implementation it is usable even where the adhesive joint is difficult of ac¬ cess; and not least, that it gives a very good ' securing ef¬ fect, particularly in conjunction with joggled joints. The invention is of course not restricted to the illus¬ trated and described embodiments, alterations and modificat- ions thus being possible within the scope of the following claims .

Claims: CLAI MS 1. Device for securing an overlap adhesive joint be- tween two workpieces, in the form of vehicle body panel parts, particularly a joggled joint, characterized in that it includes a bridge element with its first end adapted for en¬ abling supporting engagement against the surface of the first workpiece at a distance from the joint, and its second end adapted for achieving joint securing pressure against the surface of the second overlapping workpiece in the region of the joint; an attachment plate adapated to enable its attach¬ ment with the aid of a detachable adhesive joint on the surface of the first workpiece in the region between the joint and the location of engagement of said first end against the surface of the first workpiece; and means for lockably connecting and tightening the bridge element and attachment plate for pressing the bridge element, which has been applied for securing the joint, against the workpieces with said first end engaging agains't said first workpiece and said second end achieving securing pressure on the joint, this pressure being determined by the degree of tightening. 2. Device as claimed n claim 1, charact erized in that the attachment plate is adapated for being attached to the first workpiece with the aid of double-sized adhesive tape . 3. Device as claimed in claim 1 or 2, chara ct erized in that the adhesive utilized in the adhesive joint holding the attachment plate has the property that the adhesive joint obtained on application has substantially higher resistance to tensional stress substantially normal to the first work- piece than to peeling or sheering action, so that the plate can be readily removed after the securing process is termina¬ ted. 4. Device as claimed in any one of claims 1, 2 or 3, characterized in that the adhesive utilized in the adhesive joint for the attachment plate is selected such that the ad¬ hesive joint obtained on application relinquishes its hold at a predetermined tensional stress substantially normal to the first workpiece. 5. Device as claimed in any one of the preceding claims, characterized in that the second end of the bridge element is adapted for direct engagement against the second workpiece . 6. Device as claimed in any one of claims 1 - 4, characterized in that said second end of the bridge element is adapted for achieving joint-securing pressure via a sepa- rate press element which can be adjusted separately in relat¬ ion to said second end. 7. Device as claimed in claim 6, characterized in that the press element is elongate and adapted for placing along a longitudinal joint, the press element having at least two spaced engagement surfaces for longitudinally separated engagement against the overlapping part of the second work- piece . 8. -Device as claimed in any one of the preceding claims, characterized in that said connection means and brid- ge element are at least limitedly displaceable in relation to each other in the longitudinal direction of the bridge ele¬ ment . 9. Device as claimed in any one of the preceding claims, characterized in that said connection means and the bridge element are at least limitedly rotatable in relation to each other . 10. Device as claimed in any one of the preceding claims, characterized in that said connection means includes a screw element upstanding from the attachment plate, said screw element being intended to pass through a corresponding preferably longitudinally elongate aperture in the bridge element, and a nut element intended for screwing on to the screw element projecting through the aperture, such as to engage against the bridge element.

Inventors: BERGMAN NILS-ERIK, BERGMAN, NILS-ERIK
Applicants: FOLKSAM AUTO AB
Application year: 1986
Main classification: B25B11
IPC codes: B25B5, B25B11