An apparatus for masking, a method of manufacturing the apparatus and the use thereof

TECHNICAL FIELD

The present invention relates to an apparatus for masking holes and/or projections on painting or other surface treatment, comprising a strip-shaped carrier on which masking devices are disposed.

The present invention also relates to a method of manufacturing an apparatus according to the foregoing, a continuous series of masking devices with associated strip-shaped carriers being manufactured, whereafter a further continuous series is manufactured.

The present invention also relates to use of an apparatus according to the foregoing.

BACKGROUND ART

In painting, such as spray painting, or other surface treatment of objects, it is an often occurrence to mask screw holes, or other holes and pins or other projections in order to prevent surface treatment of those places where it is not desired, such as in threads or the like. Many masking devices, such as different types of sleeves or plugs, are intended to be handled manually, which is both a time-consuming and monotonous work. Thus, it is of major interest in the art to automate the handling of masking devices.

However, masking devices are often of one piece manufacture, which implies that, after manufacture, they are placed in a magazine with random orientation. The conversion of the masking devices from this state into a state where they are well-positioned and oriented is difficult per se to automate, since this places extremely high demands on recognition and gripping devices.

It is previously known in the art to position plugs on adhesive, elongate thin strips. The plugs are intended for closing off pipes and the like at their ends and are thus not intended to be removed again. The open pipe end is placed in register with the

impression device which presses the plug into the pipe. No actual handling of the plug, apart from the impression operation, is thus relevant in this context.

WO 2005/009625 discloses the masking of holes with the aid of a "stack" of conical masking plugs that are hollow and partly insertable in one another. The outermost plug is passed into a hole which is to be masked, whereafter the rest of the stack is withdrawn and separated from the inserted plug. Thereafter, the stack is moved further to another hole where the currently outermost plug is inserted and the remaining plugs are separated from the inserted plug. The masking plugs are intended to shrink and fall off when they have fulfilled their function, typically when heating takes place, for example in connection with powder spraying.

The drawbacks in these disclosures are numerous. For example, heating is required for the masking plugs to shrink, which may possibly not take place to a sufficiently high degree or at a suitable point in time in the surface treatment in question.

The inserted plugs must be adapted to be insertable in one another, which implies that only one size or type of masking plug can be grouped in one and the same stack, hi addition, extremely stringent demands are placed on material properties and dimensioning of the plugs in order, on the one hand, for them to be able to fit into and remain in position in holes as intended, and, on the other hand, in order that the plugs release from one another at a suitable place, i.e. in the transition between the outermost, inserted plug and the remaining plugs in the stack. Finally, the plugs included in the stack must be manufactured one by one and thereafter united together in the stacks, which ought not be excessively long. Consequently, manufacture and storage of this type of masking plug is of necessity complicated.

PROBLEM STRUCTURE

There is thus a need in the art to provide automated masking, at the same time as handling and manufacture of the masking devices is simple.

SOLUTION

The objects forming the basis of the present invention will be attained if the apparatus intimated by way of introduction is characterised in that the carrier is sectioned, with at least one masking device and at least one gripping member per section.

Regarding the manner of manufacture, the objects of the present invention will be attained if the one end of the first-mentioned series is joined together with one end of a subsequent series.

Regarding use according to the present invention, the objects of the invention will be attained if each respective gripping member is grasped by a gripper before being separated from the strip-shaped carrier by a separator device.

Further advantages will be attained if the present invention is moreover characterised by one or more of the features as set forth in appended Claims 2 to 8, 10 to 12 and 14 to 15, respectively.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The present invention will now be described in greater detail hereinbelow, with reference to the accompanying Drawings. In the accompanying Drawings:

Fig. 1 is a perspective view of an apparatus for masking, while in use;

Fig. 2 is a close-up in perspective of a part of the apparatus according to Fig. 1, but seen from a slightly different angle;

Fig. 3 is a perspective view of a magazine for the masking apparatus; and

Fig. 4 is a perspective view of a part of the apparatus according to the present invention during one phase in its manufacture.

DESCRIPTION OF PREFERRED EMBODIMENT

Fig. 1 broadly shows an apparatus for masking according to the invention. The apparatus 1 comprises a large number of masking devices 2 in the form of plugs or sleeves. Each one of the masking devices 2 is disposed on an elongate strip or carrier 3, preferably in one piece therewith. The strip 3 and the masking devices 2 are advanced for use from a magazine 4. Advancement is carried out by tandem-disposed advancement devices 5 in the form of wheels so that the foremost masking device 2 is positioned in front of a separator device 6 where separation of this masking device 2 takes place from the elongate strip 3. In connection with the separation, the separated part of the strip 3 is grasped by a gripper 14.

Fig. 2 shows the masking devices 2 in close-up. In the Figure, the masking devices 2 are in three different versions, namely conical, cylindrical and also in the form of a right- angled prism. Depending on the field of application, all of the masking devices 2 could, however, be identical. The intention with providing different masking devices in sequence after one another and repeating this sequence a large number of times on the elongate strip 3, is that an object which displays a plurality of different types of holes or projections which are to be masked may be given complete masking in one and the same operation, if the holes or the projections are always masked in the same sequence. Thus, the masking operation may readily be automated even if the holes or projections require different types of maskings. Only one dispenser apparatus is required for masking all types of holes.

The masking devices 2 shown in the Figure are preferably provided with an inner cavity open towards the end so that they function for both masking of holes and projecting pins or the like. However, it is possible to make the masking devices solid. Nor need the cross-sectional configuration of the inner cavity of necessity correspond to the outer cross-sectional configuration. A masking device 2 with a rectangular outer contour could be provided with a cavity which has a circular cross section, and vice versa. However, it should be observed that the positioning of a masking device 2 with a circular cross section is somewhat easier, since it needs no precision in the rotational

direction. Correspondingly, the positioning of conical or otherwise tapering masking devices 2 is quite simple, since the shape of the masking device 2 affords a certain guiding function.

The material in the masking devices 2 is preferably a rather soft formable material, which is sufficiently rigid to permit a guidable insertion in holes or onto projections which are to be masked, but at the same time sufficiently soft to be able to be compressed and thereby accommodate minor differences in dimensioning or positioning. Suitable materials are ideally polymer materials in general, such as PVC, TPG, neoprene, silicon rubber and similar materials, in particular of a rubber- like character.

In all Figures can clearly be seen the strip 3 on which the masking devices 2 are disposed on its edge. As was previously mentioned, the strip or the carrier 3 is elongate in order to make for advancement in an unbroken sequence of a large number of masking devices 2 without a new strip 3 needing to be loaded into the dispenser. The strip 3 is provided with a number of through-holes 7 or alternatively recesses. These holes 7 or recesses are usable for the advancement of the strip 3 with the masking devices 2 disposed thereon, with the aid of the advancement devices 5. The holes 7 also facilitate separation, since the separator device 6 need not cut through such great quantities of material, in other words the holes 7 function in themselves as an indication of fracture. Moreover, the presence of the holes 7 or the recesses increases the flexibility of the strip 3, since a pivot function is obtained in line with each hole 7. This flexibility is utilised particularly in connection with storage in the magazine 4. Finally, the holes 7 or recesses entail a saving in materials.

Above and below the holes 7, there are provided specific indications of fracture 12 in which the separator device 6 will engage with the strip 3. The material which remains of the strip 3 after the separation forms a gripping member 8. In the preferred embodiment, each gripping member is approximately of the shape of an I. The strip shape entails that the gripping member 8 is flat and well-suited to be grasped by the gripper 14. At the same time, the masking device 2 is non-rotationally disposed on the gripping member 8

so that the orientation of the masking device 2 is known when the gripping member 8 has been grasped by the gripper 14. The strip shape and the holes 7 between the gripping members 8 to be separated contribute to the positioning and orientation being well-known in all directions, since the holes 7 afford support in the lateral direction to the gripper 14. Moreover, bevels 15 facilitate the guiding of the gripper 14 which may similarly be provided with corresponding bevels.

Fig. 3 shows a magazine 4 from which the strip 3 with the masking devices 2 is advanced by the advancement devices 5. For purposes of clarity, the masking devices 2 have been omitted from that part of the strip 3 which is located in the magazine 4. The magazine 4 includes a series of panels of, for example, paperboard, wood or sheet metal on which a single layer of the strip 3 rests. The strip 3 is disposed in folded form on each respective panel 9. The folded form is in zigzag or sinusoidal form with gentle curves and, for purposes of clarity, has been shown as quite loose in Fig. 3, while as tight a curving of the strip 3 as possible is of course to be preferred, since this saves space. At the end walls 10 of the panels 9, the strip 3 is transferred from one panel to another. Thus, a continuous strip 3 may be longer than that which is accommodated on a single panel 9. A magazine 4 which houses a large number of panels 9 may thus accommodate a considerable strip length and a large number of masking devices. This implies that a replenishment of the magazine 4 and switching to a new tape 3 only need take place at relatively long intervals. In order for the strip 3 not to become tangled, it is an advantage, on the one hand if the panels 9 are removed in sequence when they are emptied and, on the other hand, if the magazine 4 is twisted half a turn when such removal takes place, so that the strip 3 will always be drawn out from that end of the magazine which lies most proximal the advancement devices 5.

The magazine 4 may naturally have completely different forms or shapes, such as a coil or a reel on which the strip 3 is disposed.

While the apparatus according to Figs. 1 to 3 is in use, the strip 3 with the masking devices 2 is fed forwards by the advancement devices 5 which comprise at least one pair of wheels with projections 11 which fit into the holes or recesses 7 in the strip 3 so that

the strip may be driven forwards when the wheels 5 rotate. The advancement may also be put into effect by means of other advancement devices than the wheels 5, for example with the aid of strips provided with projections or by pincer feed.

The advancement is suitably put into effect stepwise, so that one masking device 2 at a time is advanced up to the position in front of the separator device 6. Before the separator device 6 separates the gripping member 8 from the strip 3, the gripper 14 also has time to grasp the gripping member 8. Thereafter, the strip 3 is advanced forwards a further step so that a new masking device 2 with associated gripping member 8 may be separated. The strip 3 is surrounded, on its way towards the separator device, by supporting means and guides which, for purposes of clarity, have been omitted from Figs. 1 and 2.

The separation operation is shown particularly clearly in Fig. 2 and the separator device 6 includes a sharp edge, e.g. in the form of a knife or scissor blade which engage at the indication of fracture 12 provided in the strip. The direction of movement of the separator device 6 is transverse in relation to the longitudinal direction of the strip 3, regardless of how this is oriented.

As was mentioned previously, the gripper 14 grasps the gripping member 8 just before the separator device 6 has separated it from the strip 3. By such means, the risk is avoided that the masking device 2 with its associated gripping member 8 is dropped. Since the position of the masking device 2 and its orientation are well known when the masking device arrives at the separator device 6, this implies that the position and orientation are also known when the gripper 14 has grasped the gripping member 8. From this position, the gripper 14 may execute movements which, on the one hand, displace the masking device 2 to another position in space and, on the other hand, turn or twist it so that it has a different orientation. The new position and the new orientation prepare the masking device 2 for insertion into a hole or positioning on a pin which is to be masked. The gripper 14 may alternatively include gripping means which are previously known in the art, for example suction cups or a gripping jaw.

The masking operation proper, i.e. the placing of the masking devices 2 in the holes which are to be masked or on the projections which are to be masked, respectively, takes place with the aid of the movable gripper. Since the masking device 2 is collected by the gripper 14 at a place which is well-defined, and its orientation is likewise equally well-defined, the positioning of the masking device 2 may be carried out with the aid of an industrial robot in accordance with known technology.

The strip 3 may carry mutually identical masking devices 2 and then operate for masking substantially the same size or size range of holes and also for masking projections if their thickness keeps within the same size range and on condition that the masking device 2 is hollow. When masking of a plurality of different hole sizes or shapes, or alternatively sizes and shapes of projections, two or more different types of masking devices will be required for one and the same product. Such products may nevertheless be masked in a single procedure and with one and the same masking apparatus, on condition that the different types of masking devices 2 are placed out on the strip 3 in the number and in the sequence required for rapid and efficient masking of a product. The sequence of masking devices 2 which is suitable for masking a product is thereafter repeated periodically on the strip 3, so that a long series of products may be masked after one another in an automatic process. In order for such an adaptation of the strip 3 and the masking devices 2 carried thereon to be economically viable, it is nevertheless necessary that the manufacturing series are sufficiently long for such an adaptation of the masking apparatus 1 to be profitable. However, against these costs the fact must be taken into consideration that either a plurality of masking devices after one another mask different types of holes or projections, or alternatively that manual masking must be put into effect of certain of the holes or projections.

On use of the masking apparatus 1, an automatic process is advantageously also employed for removing the masking devices 2 after completed surface treatment. In such instance, use is made of the gripping members 8 for realising an engagement by a gripper which pulls the masking devices 2 loose from the product in a manner analogous with how they were applied. Naturally, it is also possible to remove the masking devices manually, if desired.

Manufacture of the masking apparatus 1 is carried out according to the preferred embodiment in series or segments which are of moderate length to be able to be accommodated in an injection moulding or casting tool. Such segments, which may accommodate one or more sequences of different masking devices 2 after one another must be united into one long, continuous strip 3 which permits the effective, automated processing as was described earlier. In order to make this possible, there is provided as shown in Fig. 4, an anchorage device 13 at one end of a strip which has been cast or injection moulded. The anchorage device 13 is thinner than the gripping member 8 and the strip 3 but has the same extent in the vertical direction as them. The anchorage device is further provided with holes or recesses 7 corresponding to those between the gripping members 8. On manufacture, the strip 3 is displaced laterally so that only the anchorage device 13 will, right from the outset, be inserted in the tool for casting or injection moulding. The anchorage device 13 will therefore become an integral part in that section which is now cast, and a whole strip 3 which has been extended by the length of the last-manufactured section is the result. Also this strip has, at its outer end, a new anchorage device 13 which is ready for anchoring in the next strip segment which is manufactured.

Depending on choice of material, other forms of interlinking of the different strip segments may be conceivable. For example, the strip sections may be fused together or glued together so as to form one continuous strip 3.

DESCRIPTION OF ALTERNATIVE EMBODIMENTS

In the Figures, the strip 3 has been shown as standing upright on edge. It should be understood that advancement, separation and gripping of the gripping member 8 with the masking device 2 disposed thereon would function just as well if the orientation of the strip were different, for example turned through a % of a revolution to a recumbent position or vertical with a feeding direction either straight upwards or straight downwards. The orientation of the magazine 4 may also be different from that in the preferred embodiment.

A further method of varying the invention is that the method of advancement and separation of the elongate strip 3 takes place with the aid of an apparatus which is movable together with the gripper 14 which grips the gripping member 8 and places it where masking is to take place. Since the gripper 14 need not reciprocate any length between the separator device 6 and the site of the masking on the product, the tempo of automation can be raised even further.

The invention may be modified without departing from the scope of the appended Claims.