SHAFT COVER SYSTEM, AND METHOD FOR SEPARING A COVER FROM A SHAFT COVER

Description

[0001] The invention relates to a manhole cover system, a magnetic cover for such a manhole cover system, and a method for separating a surface covering from a manhole cover of a manhole cover system.

[0002] Road construction often incorporates a manhole system to ensure water drainage from the road, as well as for inspection and maintenance of wastewater and electrical lines such as telephone and internet. Road construction typically occurs in two stages: a first stage, in which the provisionally completed road is opened to traffic for a certain period. The surface of this first stage is a few centimeters lower and coarser (called HMT) than the road surface will be once the final pavement is in place. However, in this provisional stage, the concrete manhole pipes are already installed and set in a concrete base. The adjustable manhole, known as the NIVO manhole cover, is embedded in this base to allow for future height adjustments. The manhole covers are also installed at this initial provisional height.

[0003] After a certain period, for example, when the surface has settled due to vehicle traffic, the final layer of asphalt is applied up to the intended height. This final layer (top layer) completely covers all manhole covers. Before the asphalt is laid, the manholes are sometimes sprayed with a release agent or covered with temporary covers. These temporary covers are expensive to procure, store, clean each time, and are manually palletized multiple times (upon delivery and return) to prevent the top layer from adhering. In practice, however, this system is only partially effective because the release agent is applied too early and thus evaporates prematurely or is simply forgotten, and costly cleaning is required. Another solution involves adhesive films that are applied to the metal of the manhole cover.Depending on the surface of the metal manhole, various surface treatments are chosen to allow for the later removal of the adhesive coating. However, at a temperature of 170 °C during the application of the coating layer, the adhesive film and / or the adhesive itself can melt or evaporate, meaning that the coating may still be in direct contact with the manhole cover, at least in some sections, and adhere to it. In most cases, the adhesive bonds with the manhole cover, sometimes resulting in even worse outcomes, as it becomes almost impossible to completely remove the adhesive film after cooling.

[0004] After the final layer or surface course has been applied, the manhole cover must be pulled through it using a specially designed hydraulic pulling system. Following this, the manhole ring, in which the cover rested, is built up to the correct level and grouted underneath. Afterward, the surface course must be removed from the manhole cover or manually sharpened. However, some manhole covers do not simply have a smooth surface but are decorated with names, coats of arms, or other graphics in relief. This often makes removing the surface course extremely time-consuming. Manual sharpening can damage or even destroy these graphics. This time-consuming work leads to enormous additional costs, which must be avoided.On a longer new road section, the crew often spends most of their time cleaning the manhole covers of the surface layer, as the client's specifications must be met.

[0005] (US 2009 / 252552 A1) describes an additional manhole cover suitable for covering a manhole cover. The additional manhole cover comprises a material layer with a thickness ranging from 0.01 in to 1.5 in and an attachment device for attaching the material layer to the manhole cover. In some embodiments, this attachment device includes magnets that are placed on or embedded in the material layer. A method for applying a coating layer comprises placing a manhole cover on a manhole in an area to be coated, placing an additional manhole cover on the manhole cover, and applying the coating layer to the manhole cover and the additional manhole cover. The method further comprises removing the manhole cover and separating the additional manhole cover from the manhole cover.

[0006] KR 2019 / 0082613 A describes a manhole cover system comprising: a manhole cover and a magnetic cover for covering a side of the manhole cover facing away from a manhole, wherein the magnetic cover is designed such that its size is essentially the same as the size of the side of the manhole cover facing away from the manhole, and wherein the magnetic cover and the manhole cover are held in a positionally fixed relationship to each other by a magnetic force, wherein the magnetic cover is designed at least partially as an electromagnet, and wherein the magnetic cover comprises at least one magnetic foil and at least one protective foil, wherein the magnetic foil is arranged on the side of the magnetic cover facing the manhole cover and the protective foil is arranged on the side of the magnetic cover facing away from the manhole cover.

[0007] In view of the foregoing, it is therefore an object of the present invention to provide a manhole cover system and a method for separating a covering layer from a manhole cover of a manhole cover system, thereby avoiding or at least reducing rework for cleaning the manhole cover.

[0008] The problem is solved by a manhole cover system and a method for separating a surface covering from a manhole cover of a manhole cover system according to the independent claims. Advantageous embodiments of the invention are contained in the dependent claims.

[0009] According to the invention, a manhole cover system comprises a manhole cover and a magnetic cover for covering a side of the manhole cover facing away from a manhole, wherein the magnetic cover is designed such that its size essentially corresponds to the size of the side of the manhole cover facing away from the manhole, and wherein the magnetic cover and the manhole cover are held in a positionally fixed relationship to each other by means of a magnetic force.

[0010] The magnetic cover, i.e., a cover that applies magnetic force, thus covers the manhole cover on the side where the surface course is applied, preventing the surface course from adhering directly to the side of the manhole cover facing away from the manhole. The fact that the size of the magnetic cover "essentially" corresponds to the size of the manhole cover is intended to account for the relatively large tolerances and manufacturer-specific dimensions that can occur, particularly in road construction. While a close match of dimensions is desirable to allow the surface course to be applied as close as possible to the manhole cover, while conversely minimizing any overlap, certain deviations are therefore acceptable in the interest of manufacturing efficiency.

[0011] The magnetic force exerted by the magnetic cover allows it to be held in a fixed position relative to the manhole cover. For this to work, the manhole cover itself is either partially magnetic or can accommodate a magnetic adapter component that holds the magnetic cover in a fixed position relative to the manhole cover. Such an adapter component can be screwed into the manhole cover or otherwise inserted in a form-fitting manner. In many cases, however, the manhole cover itself, being a cast iron cover, is already magnetic.

[0012] The magnetic cover is configured such that the magnetic force attracts the manhole cover, at least to the extent necessary to achieve a fixed position between the magnetic cover and the manhole cover. The magnetic force should be at least strong enough to prevent lateral forces during the application of the surface covering from causing a relative displacement between the magnetic cover and the manhole cover in the direction of the lateral forces.

[0013] As explained above, the magnetic cover can be easily installed on a manhole cover to prevent the covering material from adhering to it. In particular, the secure connection between the magnetic cover and the manhole cover can be maintained even if the manhole cover is wet, oily, or damaged.

[0014] The magnetic cover can, in principle, be reused multiple times. However, since the coating adhering to it can be a nuisance, or since the magnetic cover is no longer in its original state due to damage from applying or removing the coating, it can also be used as a disposable item at a comparatively low cost.

[0015] In one embodiment, the magnetic cover has at least on its side facing away from the manhole cover a recess for lifting the magnetic cover.

[0016] The opening can be an undercut or a through-opening. The magnetic cover can be lifted via this opening itself. If the manhole cover, together with the magnetic cover, is only to be lifted via an opening in the magnetic cover, the magnetic force acting between the magnetic cover and the manhole cover must be at least as great as the weight of the manhole cover. Alternatively or additionally, the opening can be designed so that it engages a manhole cover recess, such as a central hole or a so-called pilot hole, and thus the magnetic cover is lifted along with the manhole cover. In this case, the magnetic force does not need to support the weight of the manhole cover but can simply be designed to maintain a fixed position during the application of the surface covering.The magnetic force can also be less than the weight of the manhole cover in order to cause separation from the manhole cover by lifting the magnetic cover due to the set force ratio.

[0017] According to further training, the magnetic cover and / or the manhole cover is designed, at least in sections, as an electromagnet.

[0018] Electromagnets can be used to switch the magnetic force on and off, or to vary its strength and / or direction. For example, the magnetic cover can be positioned on the manhole cover with little or no magnetic force, and only after positioning is complete can the magnetic force required to maintain the position be applied. Separation of the magnetic cover from the manhole cover can also be facilitated by eliminating or reducing the magnetic force, or by reversing the direction of the force.

[0019] According to the invention, the manhole cover system comprises a magnetic cover, wherein the magnetic cover is designed at least partially as a permanent magnet and / or electromagnet.

[0020] The term "section-wise" can refer to an arrangement in a plane parallel to one side of the magnetic cover facing the manhole cover, as well as in a direction perpendicular to this plane. A permanent magnet can provide the magnetic force through the magnetic cover in a simple and cost-effective manner. However, as explained above, an electromagnet can offer greater functionality. A combination of a permanent magnet and an electromagnet allows for greater application flexibility, as the magnetic cover can be used with the permanent magnet regardless of whether the electromagnet is also available.

[0021] In particular, the magnetic holding force that can be applied by the magnetic cover is between 20 and 80 cN / cm 2< , preferably between 40 and 70 cN / cm 2< , especially preferably between 50 and 57 cN / cm 2< .

[0022] The specifications for holding force refer to an air gap d = 0 mm and are defined as pull-off forces in cN / cm 2< perpendicular to the contact surface.

[0023] If the magnetic force is too low, maintaining a stable position between the magnetic cover and the manhole cover during the application of the surface course and the associated external forces cannot be guaranteed. Conversely, excessively high magnetic forces can unnecessarily increase the effort required to separate the magnetic cover from the manhole cover.

[0024] According to the invention, the magnetic cover comprises at least one magnetic sheet. Magnetic sheets can be easily cut to size as required and can also be readily combined with another substrate material. Both semi-anisotropic and anisotropic magnetic sheets can be used.

[0025] Semi-anisotropic magnetic sheets have the advantage that they are PVC-coated (vulcanized) and are not glued to the magnetic sheet, but welded.

[0026] However, they have the disadvantage of having a weaker adhesive force than anisotropic magnetic foils.

[0027] Anisotropic magnetic sheets have the advantage that they are not coated and can be bonded to various foreign substrates.

[0028] However, they have the disadvantage of being more susceptible to bending in their raw state.

[0029] Preferably, the thickness of the magnetic foil is greater than or equal to 0.5 mm. More preferably, the thickness of the magnetic foil is less than or equal to 1 mm. In particular, the thickness of the magnetic foil is approximately 0.75 mm.

[0030] Magnetic sheets with a thickness of 0.5 mm to 1.5 mm can already provide sufficient magnetic force and, considering the associated costs and ease of processing, are also suitable for disposable items. Furthermore, the overall height of the magnetic cover can be kept relatively low. Therefore, it is possible to design the magnetic cover with sufficient elasticity that it does not need to be completely separated from the manhole cover, but can instead be peeled off, i.e., separated in stages.

[0031] According to one embodiment, the magnetic foil has a remanent flux density BR of 150 to 200 mT, in particular 170 to 180 mT.

[0032] For example, a magnetic foil with a thickness of 0.75 mm and a remanent flux density BR of 179 mT can be used.

[0033] In particular, the coercive field strength of the magnetic foil is in the range of 100 to 110 kA / m, especially around 103 kA / m. According to the invention, the magnetic cover comprises at least one protective film.

[0034] The protective film can be single- or multi-layered. Preferably, the film is chemically resistant. The thickness can be, for example, in the range of 0.3 to 0.4 mm to achieve a relatively thin magnetic cover.

[0035] According to the invention, the protective film is a self-adhesive plastic film, wherein the protective film is connected to the magnetic film via an adhesive film formed by the plastic film.

[0036] The magnetic foil and protective film can thus be easily bonded. Alternatively, the magnetic foil can also be bonded to the protective film using other application methods.

[0037] In one design, the protective film is printable, in particular UV printable.

[0038] The magnetic cover can therefore be directly printed with handling instructions or advertising content. For this purpose, the protective film is placed, for example, on the side of the magnetic cover facing the manhole cover, so that the print on the protective film remains visible even when the magnetic cover is positioned on the manhole cover. Even without a print, such an arrangement of the protective film can be advantageous to protect the magnetic cover after it has been positioned on the manhole cover until the final layer of material is applied.

[0039] In particular, at least the magnetic foil and / or the protective foil are / are usable in a temperature range of -20°C to +100°C, especially from -15°C to +80°C, especially also for short periods up to 180°C, particularly preferably up to 200°C.

[0040] The magnetic foil and / or the protective film can therefore be used under normal ambient conditions. Even when applying a topcoat at approximately 170 °C, at least short-term heat resistance may be sufficient to prevent significant damage to the magnetic foil and / or the protective film. If the protective film can adequately protect the magnetic foil, it may be sufficient to make only the former heat-resistant. Due to the heat resistance of the magnetic foil and / or protective film, the hot topcoat cannot penetrate to the manhole cover.

[0041] In one embodiment, at least one side of the magnetic cover facing outwards in the manhole cover system is designed to be slip-resistant, at least in sections.

[0042] The outward-facing side of the magnetic cover is specifically the side that, when the cover is positioned on the manhole cover, faces away from the manhole cover. This prevents pedestrians or vehicles from slipping on the magnetic cover before the final surface covering is applied. Alternatively or additionally, such a coating can also be applied to the side of the magnetic cover facing the manhole cover to further secure the cover against lateral forces. Slip resistance can be achieved through appropriate material selection and / or surface texturing. The outward-facing side of the magnetic cover can, for example, be formed by the magnetic foil or protective film.

[0043] In another aspect, the invention also relates to a method for separating a surface covering from a manhole cover of a aforementioned manhole cover system, comprising the steps of: Arrangement of the manhole cover system on a manhole, wherein the manhole cover faces the manhole and the magnetic cover faces away from the manhole, application of the covering layer, wherein at least part of the magnetic cover of the manhole cover system is covered by the covering layer, lifting of the magnetic cover, and release and / or overcoming the holding force of the magnetic cover to detach the manhole cover from the magnetic cover.

[0044] The manhole cover and the magnetic cover, as components of the manhole cover system, do not need to be placed on the manhole simultaneously and thus pre-assembled. Initially, only the manhole cover can be placed on the manhole, while the magnetic cover must be installed no later than when the surface covering is applied. The magnetic force then holds the magnetic cover in a fixed position relative to the manhole cover during application. If the magnetic cover includes electromagnets for this purpose, these must then be activated accordingly.

[0045] A hydraulic pulling system or other tool can be used to lift the magnetic cover. The magnetic cover is pulled through the surface covering, which adheres to it. Lifting can occur simultaneously with detaching the magnetic cover from the manhole cover. In this case, the magnetic force is less than the weight of the manhole cover, or the manhole cover is held on the manhole by another means, and the pulling force on the magnetic cover is greater than the holding force between the magnetic cover and the manhole cover caused by the magnet. These force ratios can be controlled or varied by using electromagnets in the magnetic cover. Switching off an electromagnet completely eliminates its magnetic force. Alternatively, the magnetic cover can be detached from the manhole cover only after it has been lifted or removed from the manhole.In this case, the magnetic cover can, for example, exert a magnetic force that is at least greater than the weight of the manhole cover, at least during lifting or removal. Subsequent separation or release can then be achieved by reducing the magnetic force in the case of electromagnets or by applying tensile forces that overcome the holding force.

[0046] The invention will now be explained in more detail with reference to one embodiment and the accompanying figure. The figure shows, in detail: Figure 1 shows a schematic cross-sectional view of a manhole cover system according to an exemplary embodiment of the invention.

[0047] Figure 1Figure 1 shows a schematic cross-sectional view of a manhole cover system 1 according to an exemplary embodiment of the invention. The manhole cover system 1 covers a manhole 30 and comprises a manhole cover 10 and a magnetic cover 20. The manhole cover 10 is placed on the manhole 30, and the magnetic cover 20 is placed on top of the manhole cover 10. To protect the manhole cover 10 during the application of a surface covering, the magnetic cover 20 is positioned on the manhole cover 10 such that it fits snugly over it. The manhole cover 10 and the magnetic cover 20 thus have essentially the same shape in a plane parallel to the side of the manhole cover 10 facing the manhole. To enable the magnetic cover 20 to be lifted, it has an engagement 21.This is shown here as an example designed as a through-opening, whereby a corresponding lifting device can be inserted through the through-opening as an engagement 21 of the magnetic cover 20 and through a manhole cover engagement 11 of the manhole cover 10, which is also designed as a through-opening. However, the engagement 21 of the magnetic cover 20 can also be configured such that a lifting tool only engages the magnetic cover 20.

[0048] In the illustrated embodiment, the magnetic cover is formed from a magnetic foil 22 and a protective foil 23. The magnetic foil 22 and the protective foil 23 can be single-layered or multi-layered. Multiple magnetic foils 22 and protective foils 23 can also be arranged one behind the other or alternately. Figure 1The magnetic foil 22 is positioned on the side of the magnetic cover 20 facing the manhole cover 10. This allows the magnetic force exerted by the magnetic foil 22 to act directly on the manhole cover 10 without any reduction in holding force due to additional spacing or material shielding. The protective foil 23 is positioned on the side of the magnetic cover 20 facing away from the manhole cover 10. This foil is chemically and heat-resistant, preventing damage to the underlying magnetic foil 22 during the application of a surface covering. Similarly, the magnetic foil 22 itself can also be chemically and heat-resistant to protect the manhole cover 10 and prevent material adhesion. The protective foil 23 is also slip-resistant, thus not only protecting the magnetic foil 22 but also reducing the risk of accidents for pedestrians and / or vehicles crossing the manhole cover system 1.

[0049] For example, a magnetic cover 20 can be a disposable magnetic sheet 23 with a thickness of 0.75 mm, whereby the magnetic cover consisting of magnetic sheet 22 and protective sheet 23 has a thickness of up to 1.1 mm. The protective sheet 23 consists of a PVC-welded self-adhesive film with UV printing of manufacturer specifications or handling instructions.

[0050] The magnetic sheets have dimensions of 0.5 - 1.5mm, and the drill hole diameters can vary.

[0051] With a material thickness of 0.75 mm, the magnetic foil 23, as a semi-anisotropic magnetic foil, exhibits a holding force of 50 cN / cm², and the magnetic foil 23, as an anisotropic magnetic foil, exhibits a holding force of 57 cN / cm². The holding force specifications refer to an air gap d = 0 mm and are defined as pull-off forces in cN / cm² perpendicular to the contact surface.

[0052] The magnetic foil 23 has a remanent flux density BR of 179 mT, a coercive field strength BHc of 103 kA / m, a maximum energy product BH of 5.49 kJ / m³ or 0.96 MGOe, a density of 3.6 g / m³, and a Shore D hardness of 55. The maximum operating temperature range is -15 °C to +80 °C, with short-term exposure to 180 °C / 220 °C. The pole spacing is 2.1 mm, and the magnetic foil 23 is multi-pole on both one and two sides and coated with a protective lacquer on the magnetic side.

[0053] The magnetic foil 23 consists of approximately 89% barium ferrite or strontium ferrite, approximately 9.5% plastic elastomers, here without PVC, and the remainder of 1.5% binders and plasticizers.

[0054] The invention is not limited to the described embodiment. It can also be used to protect inlet / drainage shafts, which may have square or rectangular shapes. Reference symbol list

[0055] 1 Manhole cover system 10 Manhole cover 11 Manhole cover access 20 Magnetic cover 21 Access (magnetic cover) 22 Magnetic foil 23 Protective foil 30 Manhole

Claims

1. A manhole covering system (1), comprising: a manhole cover (10) as well as a magnetic cover (20) for covering a side of the manhole cover (10) facing away from a manhole (30), wherein the magnetic cover (20) is designed in such a way that its size essentially corresponds to the size of the side of the manhole cover (10) facing away from the manhole (30) and wherein the magnetic cover (20) and the manhole cover (10) can be kept in a fixed position relative to each other by a magnetic force, wherein the magnetic cover (20) is at least sectionally designed as a permanent magnet and / or electromagnet, and wherein the magnetic cover (20) consists of at least one magnetic sheet (22) and at least one protective film (23), wherein the magnetic sheet (22) is arranged on the side of the magnetic cover (20) facing the manhole cover (10) and the protective film (23) is arranged on the side of the magnetic cover (20) facing away from the manhole cover (10), and wherein the protective film (23) is a self-adhesive plastic film, wherein the protective film (23) is connected with the magnetic sheet (22) via an adhesive film formed by the plastic film.

2. The manhole cover system (1) according to claim 1, wherein at least the side of the magnetic cover (20) facing away from the manhole cover (10) has a recess (21) for lifting the magnetic cover (20).

3. The manhole cover system (1) according to claim 1 or 2, wherein the manhole cover (10) is at least sectionally designed as an electromagnet.

4. The manhole cover system (1) according to one of claims 1 to 3, wherein the magnetic holding force that can be applied by the magnetic cover (20) lies between 20 and 80 cN / cm2, preferably between 40 and 70 cN / cm2, especially preferably between 50 and 57 cN / cm2.

5. The manhole cover system (1) according to one of claims 1 to 4, wherein the magnetic sheet has a thickness of 0.5 mm to 1.5 mm, in particular of about 0.75 mm.

6. The manhole cover system (1) according to one of claims 1 to 5, wherein the magnetic sheet (22) has a remanence flux density BR of 150 to 200 mT, in particular of 170 to 180 mT.

7. The manhole cover system (1) according to one of claims 1 to 6, wherein the coercive field strength of the magnetic sheet (22) lies in a range of 100 to 110 kA / m, in particular measuring about 103 kA / m.

8. The manhole cover system (1) according to one of claims 1 to 7, wherein the protective film (23) is printable, in particular UV printable.

9. The manhole cover system (1) according to one of claims 1 to 8, wherein at least the magnetic sheet (22) and / or the protective film (23) can be used in a temperature range of -20 °C to +100 °C, in particular of -15 °C to +80 °C, in particular for the short term at up to 180 °C, especially preferably up to 200 °C.

10. The manhole cover system (1) according to one of claims 1 to 9, wherein at least one outwardly facing side of the magnetic cover (20) in the manhole cover system (1) is at least sectionally slip-resistant in design.

11. A method for separating a surface covering from a manhole cover (10) of a manhole cover system (1), comprising the following steps: - arranging a manhole cover system (1) according to one of claims 1 to 11 on a manhole (30), wherein the manhole cover (10) faces the manhole (30) and the magnetic cover (20) faces away from the manhole (30), - applying the surface covering, wherein at least a portion of the magnetic cover (20) of the manhole cover system (1) is covered by the surface covering, - lifting the magnetic cover (20), and - canceling and / or overcoming the holding force of the magnetic cover (20) to release the manhole cover (10) from the magnetic cover (20).