WO1990012653A1

WO1990012653A1 - Masking arrangement

Info

Publication number: WO1990012653A1
Application number: PCT/SE1990/000253
Authority: WO
Inventors: Gerhard Pihl
Original assignee: Gerhard Pihl
Priority date: 1989-04-18
Filing date: 1990-04-17
Publication date: 1990-11-01
Also published as: SE8901388D0; EP0469095A1; SE8901388L; SE463400B

Abstract

Masking arrangement for masking a section (11) of a surface (10) which is to be surface-treated, and comprising a surface-covering part designed to be connected, with a bearing side, against the said surface section in a masking position. The masking arrangement also comprises a grip part (7) designed to be grasped for the purpose of applying the masking arrangement in its masking position. The surface-covering part has, on its bearing side, an area with adhesive (6) by means of which the surface-covering part is designed to be secured against the said surface section (11) in the masking position during a surface-treatment phase. During a subsequent unmasking phase, the covering part slips from the surface section, in which respect the surface-covering part has a section which tends to assume an angle such that the bearing side of the surface-covering part acquires two bearing surfaces set at an angle to each other.

Description

Title: Masking arrangement

Technical field:

The present invention relates to a masking arrangement for masking a section of a surface which is to be surface- treated, and comprising a surface-covering part designed to be connected, with a bearing side, against the said surface section in a masking position.

Prior art:

For masking a section of a surface which is to be surface- treated, in which a hole is arranged in the surface, it is known to arrange plastic plugs which are provided with flanges. These plugs must be specially designed for each individual shape and dimension of a hole, and this means that, for example, a chassis of a vehicle requires a very large set of various shapes of plugs and, in addition, the personnel must be trained to place the correct plug in the correct position. Moreover, after the surface- treatment has been completed, the plugs must be removed, which is a relatively time-consuming stage and neces- sitates a special technique since the plugs are not usually provided with any grip part which can be grasped.

The aim of the present invention is to produce a masking arrangement which has a particularly simple design and does not require an exact fitting to a hole which is to be masked, and also permits efficient handling on masking and unmasking.

Solution:

The said aim is achieved by means of a masking arrange¬ ment according to the present invention, which is charac¬ terized in that the masking arrangement comprises a- grip part designed to be grasped for the purpose of applying the masking arrangement in its masking position, and in that the surface-covering part has, on its bearing side, an area with adhesive by means of which the surface- covering part is designed to be secured against the said surface section in the masking position during a surface- treatment phase and to be removed from the said surface section during a subsequent unmasking phase, and in that the surface-covering part has at least one section which is foldably, elastically connected to the grip part and is thereby secured in a securing position during pre- stressing, for which reason the said section of the surface-covering part tends to assume an angle such that the bearing side of the surface-covering part acquires two bearing surfaces set at an angle to each other, and the said securing is achieved by means of the fact that the securing force of the adhesive during^", the said surface-treatment phase exceeds the said pre-stressing, and the said releasing is achieved by means of the fact that the securing force of the adhesive is reduced during the said unmasking phase.

Description of Figures: The invention will be described in greater detail below on the basis of an exemplary embodiment and with reference to the attached drawings, in which

Fig. 1 shows a plan view of a spread-out blank for the masking arrangement according to the invention, Figs. 2, 3, 4 show different views of the masking arran¬ gement according to the invention in the applied state on a surface which is to be masked, while Fig.5 shows two masking arrangements which have slipped from their applied position and fallen down on a surface.

Preferred embodiment:

The masking arrangement according to the invention is advantageously produced from a disc-shaped blank, prefer¬ ably of cellulose fibres, such as cardboard, pasteboard or the like, but disc-shaped plastic material or sheet- metal material is also conceivable. In the example shown, however, it is assumed that a disc-shaped material of cellulose fibres, such as cardboard, has been used. In the example shown, the blank is formed from the disc material, for example by means of stamping, in such a way that the outer contour of the blank forms the shape of two overlapping circle peripheries 1, 2, where those parts of each circle periphery which fall within the circle surfaces have been removed so that one continuous unit is formed. A common chord is thus obtained, which forms a central folding line 3. Two outer folding lines

4, 5, one on each side of the central folding line 3, are formed by diameters in each one of the two circle parts, these diameters extending parallel to each other and preferably parallel to the central folding line 3. Arranged on at least one circle section is a surface of adhesive in the form of a strand of glue 6, for example hot-melt glue, which crosses the one outer folding line

5. The two outer folding lines 4, 5 are arranged in such a way that they utilize the built-in elasticity of the disc material and the tendency to recover a neutral position in which the material is freed from stresses, as will be described in greater detail below. In contrast, the central folding line 3 does not need to have any built-in elasticity, but instead stresses in the material in the folding line are advantageously eliminated by means of a considerable gap or perforation along the folding line 3, but in such a way that the folding line continues to hold the two circle sections together.

The masking arrangement is formed by folding the two circle sections about the central folding line 3 in such a way that their areas between the central folding line and the two outer folding lines 4, 5 are moved in a direction towards each other, to be more exact in a direction such that the strand of glue 6 ends up between these two areas. In the case where hot-melt glue is used, this is carried out directly on application of the strand of glue, so that these two areas are glued together by means of the strand of glue and are held together against each other, as can be seen in Fig. 5. In this way a grip part 7 is formed, which is designed to be grasped manual¬ ly by an operator's hand, advantageously between his thumb and index finger, or alternatively by means of a gripping device in the case of automated handling. The two outer circle sections outside the outer folding lines 4, 5 are folded about the latter in a direction away from each other, that is to say in the opposite direction to the folding of the two sections which form the grip part 7, so that two flanges 8, 9 are formed. This folding is chosen such that the flanges in an unloaded state, that is to say without any built-in prestressing in the fold¬ ing lines 4, 5, form an angle to each other of less than 180°, that is to say an angle to the grip part 7 of over 90". For example, the grip part and the two flanges can be directed in such a way that they have an angle of 135° to each other.

Figs. 2, 3 and 4 show how the masking arrangement is arranged when applied on a surface 10, of which a surface section 11 is to be covered, that is to say masked by the masking arrangement. For example, this surface section 11 comprises a hole 12, in which some component in a subse-

~r quent assembly stage is to be fitted, and this hole is therefore protected during a surface-treatment of the surface 10- which, for example, can consist of the chassis of a vehicle, which chassis is to be treated with a chassis compound sprayed onto the surface 10. The hole 12 may alternatively be a drainage hole which is to be protected so that the sur ace-treatment material does not penetrate into the hole during the surface-treatment. The surface-treaπαent may also consist of the treatment of another part of a vehicle bodywork or another object, for example spray painting. The application of the masking arrangements is carried out before the surface treatment, in which respect the adhesive strand 6 is in an adhesive state, that is to say, when using hot-melt glue, at a sufficiently high temperature for the adhesive to stick securely to some part of the surface section 11 which is to be covered. The masking arrangement is grasped by the grip part 7 and is pressed straight against the surface section 11, in which respect the two flanges 8, 9 spring apart and join relatively tightly against the surface section 11. In the case where this section 11 is flat, the two flanges 8, 9 end up in the same plane, as has been shown in Fig. 3. In the event of a convex surface, the flanges adapt essentially to this surface and can form an angle to each other. The two flanges 8, 9 thus form a surface-covering part with a bearing side 13 which, in the masking position shown in Figs. 2, 3 and 4, bears against the surface section 11 and covers the latter, that is to say, in the example shown, the hole 12 and a surrounding annular section. In the example shown, each flange forms a semicircle, and together they form a circle when they lie in the same plane. The precondition for securing during the said prestressing is that the securing force of the adhesive during the surface-treat¬ ment phase exceeds the prestressing force.

When all the surface sections 11 which are to be masked have been provided with the masking arrangement according to the invention, so that other surfaces of the vehicle, for example, can be surface-treated, the vehicle is placed, for example, in a spray booth in which, for example, a chassis composition is applied to the surface 10 from the spray nozzle. The adhesive is here formulated in such a way that it is not loosened by the surface- treatment agent even if this generally has a temperature exceeding room temperature, for example about 85°. The important point here is that the strand of glue 6 does not reach its melt temperature in the masking position, that is to say during the surface-treatment phase, in which respect it may be mentioned that the disc-shaped material of the masking arrangement itself provides a certain insulation and thus a delay in the increase in temperature of the strand of glue, which in this way is unable to reach the melt temperature of the glue before the surface-treatment phase is finished. When the sur- face-treatment is finished, the vehicle is moved out from the spray booth in order to be unmasked in an unmasking phase.

The unmasking is for example integrated with a drying phase for drying the surface-treatment material, ad¬ vantageously in an oven, the temperature in certain applications being increased in relation to the surface- treatment temperature. This temperature increase is carried out to such a level that the adhesive loses its adhesive action and is loosened, that is to say, in the case of hot-melt glue, it reaches the melt temperature and the masking arrangement is thus released from the surface 10. This releasing is facilitated by the built- in elasticity of the flanges 8, 9, which in the mounted state have acquired a built-in prestressing, when these are fixed in a stretched-out state by means of the effect of the adhesive. The securing force of the adhesive is thus reduced by means of the increase in temperature of the adhesive in such a way that it falls below the prestressing force. The masking arrangement thus does not remain in the masking position when the adhesive loosens, even if a certain sticking is present between the masking arrangement and the surface-treatment agent, but instead the masking arrangement is pushed away from its masking position as a result of the built-in spring action of the flanges 8, 9, and it falls down from the masked surface, provided of course that the masking arrangement is applied against the surface 10 from below or from the side. The important factor in the change in the securing properties of the adhesive from the surface-treatment phase to the unmasking phase is the increase in tempera¬ ture of the adhesive itself. As has been mentioned above, the increase in temperature is delayed as a result of the insulating action of the surface-covering part. Use can be made of this so that the unmasking phase does not involve the surface-treated object having to be exposed to a rise in temperature. The necessary increase in temperature in the adhesive can be effected simply by means of the said delay. Despite the fact that the surface-treatment agent is sprayed at a temperature which gives the adhesive its reduced securing, the increase in temperature of the adhesive thus takes place only after the surface-treatment is completed.

Since the masking arrangement in its non-masking state recovers its basic shape, as shown in Fig. 5, the masking arrangement does not come to assume a surface-wise bearing on any surface, but only a point-wise or line- wise bearing, which minimizes the risk of sticking, for example, to a vertical, surface-treated surface. Reference 14 designates diagrammatically an underlayer, for example the floor or a ledge of the surface-treated surface, from which the masking arrangement can be easily removed. This applies regardless of whether the masking arrangement ends up with both flanges downwards or with one flange and the grip part downwards.

The invention is not limited to the exemplary embodiment described above and illustrated in the drawings, but instead can be varied within the scope of the subsequent patent claims ,_ψ For example, the folding lines 4, 5 do not have to be parallel to the central folding line 3, but should nevertheless be parallel to each other so that together they provide a level surface-covering surface. Nor do the outer folding lines 4, 5 need to be diameters, but instead they can be chords, in which respect the surface-covering part is not circular in shape, but instead acquires another shape. On the whole, the arran¬ gement can be given completely different shapes, for example the disc-shaped blank can be rectangular and divided into rectangular zones by the three folding lines. From the centre of the surface-covering part there can project a centring pin which is intended to project into the hole which is to be surface-covered. The masking arrangements can be offered in a range with various sizes of arrangements. However, the range can be made relat¬ ively limited since it does not have to be adapted exactly to the hole which is to be covered. For example, several masking arrangements can overlap each other in order to cover together a larger hole. The strand of glue 6 can be of another shape and extent. For example, the whole of one side of the blank according to Fig. 1 can be provided with an adhesive, or only two drops can be applied, one drop on each side of the folding line 5. The adhesive can be of the double-sided adhesive tape type. The masking arrangement can as a whole be an injection- moulded three-dimensional body of, for example, plastic, instead of being produced by folding of a disc-shaped material. The surface which is to be surface-covered can be a . surface without a hole, for example where some element is to be arranged subsequently.

Claims

Patent claims

1. Masking arrangement for masking a section (11₎ of a surface (10) which is to be sur ace-treated, and comprising a surface-covering part (8, 9) designed to be connected, with a bearing side, against the said surface section in a masking position, characterized in that the masking arrangement comprises a grip part (7) designed to be grasped for the purpose of applying the masking arrangement in its masking position, and in that the surface-covering part (8, 9) has, on its bearing side, an area with adhesive (6) by means of which the surface- covering part is designed to be secured against the said surface section (11) in the masking position during a surface-treatment phase and to be removed from the said surface section during a subsequent unmasking phase, and in that the surface-covering part has at least one section which is foldably, elastically connected to the grip part and is thereby secured in a securing position during prestressing, for which reason the said section of the surface-covering part tends to assume an angle such that the bearing side of the surface-covering part acquires two bearing surfaces set at an angle to each other, and the said securing is achieved by means of the fact that the securing force of the adhesive during the said surface-treatment phase exceeds the said pre¬ stressing, and the said releasing is achieved by means of the fact that the securing force of the adhesive is reduced during the said unmasking phase.

2. Masking arrangement according to Patent Claim 1, characterized in that the surface-covering part (8, 9) consists of two flanges which are elastically connected, with respect to folding movements, to the grip part (7) in such a way that they tend to both alter the angular position upon change-over from the surface-treatment phase to the unmasking phase.

3. Masking arrangement according to Patent Claim 2 , characterized in that the arrangement is made from a disc material which is folded 180° along a central folding line (3), as a result of which the grip part (7) is formed of two sections of the disc material held together and bearing against each other, and which is folded outwards from the grip part along two outer folding lines (4, 5), as a result of which the said two flanges (8, 9) in the surface-covering part are formed.

4. Masking arrangement according to Patent Claim 3, characterized in that the arrangement is formed from a blank with an outer contour which forms two overlapping circles with a common chord which forms the central folding line (3) , in which respect the two outer folding lines (4, 5) consist of two diameters parallel to the said chord.

5. Masking arrangement according to Patent Claim 4, characterized in that the disc material consists of cardboard and in that the two sections of the grip part (7) are held together by means of a strand of adhesive (6) which extends in across at least one section of the bearing side of the surface-covering part. i 6. Masking arrangement according to any one of the ^■ preceding patent claims, in which respect the adhesive has a reduced securing capacity at increased temperature, characterized in that the said adhesive is designed to maintain a temperature, during the surface-treatment .phase, at which the securing capacity exceeds the said release capacity as a result of prestressing, and to maintain an increased temperature, in the unmasking phase, at which the securing capacity is reduced in such a way that it falls below the capacity for release from the surface section which is to be masked, when the temperature increases above a normal surface-treatment temperature, and in that the arrangement is subjected to a temperature increase during the said unmasking phase, exceeding the said treatment temperature, as a result of which the arrangement slips and falls down from the masked surface (10) .