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1. WO2007091227 - A FOOTWAY PRODUCT

Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters

[ EN ]

Title

A Footway Product

Field of the Invention

The invention relates to a footway product, such as a manhole cover, having printed matter on an upper surface thereof.

Background to the Invention

It is known, for example from US 4,973,191 to provide a manhole cover including a frame and a lid having an insert plate on its upper surface. The lid is insertable into the frame which is provided in the road surface. Securing screws are provided for detachably securing the insert plate to the base portion of the lid from the underside of the lid. The insert plate is configured as an advertising area. The design on the advertising is cast into the insert plate to result in a raised configuration. The insert plate is made of bronze, brass or copper, or from plastics. The insert plate, into which the advertisement is cast, is secured to a base by means of four screw connections. The screw connection allows the insert plate to be exchanged if it is desired to change the design of the advertisement.

Disadvantages of the known arrangements include the fact that advertisement designs must be cast into the metal insert plate, which is an expensive and time consuming process. Also, because the insert plate is attached to the manhole cover by screws it is susceptible to unauthorised removal by vandals. Furthermore, holes must be cast in the recess to receive the insert plate mounting screws. The insert plate must also be drilled and tapped to allow the insert plate to the fixed to the manhole cover, which increases the time and expense involved in producing the insert plates.

Object of the Invention

It is an object of the invention to provide an improved construction of a footway product, in particular a manhole cover having an advertising area, in which the advertisement can easily and inexpensively be applied, and replaced, and which has a suitable non-slip characteristic.

Summary of the Invention

The invention provides a footway product comprising a base, an upper planar surface on the base, a raised rim surrounding the planar surface, a flexible graphic sheet adhered by means of adhesive to the upper planar surface and located within the raised rim and wherein an upper surface of the graphic sheet has graphic subject-matter printed thereon, and said upper surface of the graphic sheet is slip resistant.

Preferably the upper planar surface is on a raised portion which extends upwardly from the base and the base has a perimeter area adjacent the raised portion, said perimeter area having a plurality of upwardly extending projections to provide a slip resistant surface on said perimeter area, and wherein the tops of the projections and the rim are substantially flat and all lie in substantially the same plane as the top surface of the graphic sheet.

Suitably, the graphic sheet is a flexible plastics film, e.g. a calendered vinyl film, coated on its undersurface with a pressure-sensitive adhesive and having a transparent overlaminate film bonded to the upper surface thereof, the upper surface of the overlaminate being a skid resistant surface.

In accordance with a second aspect the invention provides a method of manufacturing a footway product comprising casting the footway product from a molten metal, shot-blasting the casting to provide a clean smooth finish on said upper planar surface, masking the upper planar surface, spray painting the remainder of the casting, removing the masking from the upper planar surface, and bonding the graphic sheet to the unpainted upper planar surface by means of an adhesive.

The footway product may be a manhole cover, or a frame for a manhole cover or a combination of both. The term "footway product" also includes access covers and frames, paviour covers and frames, and the like. The footway product may be cast from iron or steel, or it may be fabricated and pressed from a suitable sheet metal such as stainless steel, or galvanised mild steel. Alternatively, the footway product may be formed from plastic, concrete, composite materials or the like.

The footway product may be of any desired shape, for example, square, rectangular, circular, double triangular, annular or oblong. Similarly, the graphic sheet may be of any desired shape, for example, square, circular, rectangular or oblong.

Brief Description of the Drawings

Some embodiments of the invention are hereinafter described with reference to the accompanying drawings, wherein:
Figure l is a top plan view of a manhole cover according to the invention;
Figure 2 is a partial cross-sectional view of the manhole cover of Figure 1, taken along line A-A;
Figure 3 is a top plan view of a manhole cover and frame according to the invention;
Figure 4 is a partial cross-sectional view of the manhole cover and frame of Figure 3, taken along line C-C;
Figure 5 is a top plan view of a further embodiment of a manhole cover and frame according to the invention; and
Figure 6 is a partial cross-sectional view of the manhole cover and frame of Figure 5, taken along line B-B.

Detailed Description of the Drawings

A first embodiment of a manhole cover 1 in accordance with the invention is shown in Figures 1 and 2 of the drawings. The manhole cover is cast, as a solid unit, from a suitable metal, suitably by a process as described in more detail below, under the heading "Casting Method". Preferably, the manhole cover 1 is cast from iron, but it may also be cast from steel, or from a mixture of suitable metals.

The manhole cover 1 comprises a solid base 2 having an upper surface 3.

The cope pattern referred to under "casting method" below, forms the top surface of the manhole cover 1, which is provided in a perimeter area, with a raised pattern 4, e.g. a chequer pattern. In an alternative embodiment, a drag pattern could be used to form the top surface of the cover. In the embodiment shown the raised pattern is comprised of a plurality of raised protuberances 5, which are spaced apart from each other, and which are cast integrally with the base 2. In the embodiment shown the raised protuberances are of rectangular cross-section, but it will be appreciated that they can be of other shapes e.g. circular, oblong etc. The tops of the raised protuberances 5 are flat and all lie in the same horizontal plane. The purpose of the raised pattern 4 is to provide the upper surface of the manhole cover with a non-slip surface.

A central area of the upper surface 3 is provided with a raised portion 6. The raised portion 6 comprises a raised planar surface 7 adapted to receive a graphic sheet 8. Preferably, the raised planar surface is surrounded by a raised edge or rim 9. The rim 9 extends around all of the perimeter of the raised planar surface 7, e.g. similar to a picture frame.

The top surface of the raised edge or rim 9 is flat and lies in the same horizontal plane as the tops of the protuberances 5. Also, the height of the raised rim 9 above the raised planar surface 7 is substantially the same as the thickness of the graphic sheet 8, such that the upper surface of the graphic sheet 8 is flush with the top surface of the rim 9, and also lies in the same horizontal plane as the top surfaces of the protuberances 5.

Thus, a continuous raised surface is maintained across the graphic sheet and the raised chequer pattern so that there is no sudden drop over a large surface area of the cover 1 , thus avoiding a trip hazard.

By way of example, in this embodiment the thickness (i.e. height) of the base 2 of the manhole cover 1 is about 10 mm. The chequer protuberances 5, and the raised rim 9, extend 3.25 mm in height from the upper surface 3 of the cover 1. The planar surface 7, to which the graphic sheet 8 is applied, is 2.75 mm in height from the upper surface 3 of the cover 1. Thus, the top edge portion of the rim 9 is 0.50 mm above the planar surface 7. The graphic sheet 8, is 0.50 mm in thickness such that when it is applied to the planar surface 7, its top surface is flush with those of the rim 9, and protuberances 5.

The planar surface 7 of the raised surface portion is prepared to receive the graphic sheet 8, as follows. Following the casting of the manhole cover, as described below, the casting is shot-blasted to provide a clean smooth surface 7. The planar surface 7 is then masked over using a masking tape. A water based matt paint, e.g. a black paint, is applied to the upper surfaces of the manhole cover including the exposed surfaces of the protuberances 5 and rim 9, e.g. by means of an air operated paint gun. After the paint has dried, the masking tape is removed to leave the planar surface 7 as a clean, smooth, unpainted surface.

The graphic sheet 8 is then applied to the planar surface 7 and is bonded thereto by a suitable adhesive. The upper surface of the graphic sheet 8 has an advertisement or other graphic image printed thereon.

In an alternative embodiment, the casting is shot-blasted as described above and the graphic 8 is then applied to the manhole cover 1. The graphic is then masked over before paint is applied to the manhole cover.

Preferably the graphic sheet 8 is a flexible plastics film on which an
advertisement or other graphic subject matter is printed on the upper surface thereof e.g. by screen printing or electrostatic imaging, and the undersurface of the sheet is adhered to the planar surface 7 by means of an adhesive. For example, the film may be a calendered vinyl film formed with a pressure sensitive adhesive layer. The adhesive layer is protected by a removable liner before use. After printing of the image, the film is cut to the desired shape to fit snugly within the raised rim 9 of the planar surface 7.

The protective liner is removed, and the surface of the film containing the adhesive layer is applied to the surface 7 and, using a brush or a roller, the adhesive is pressed into contact with the surface 7 to adhere the film 8 to the surface.

It is important that the upper surface of the graphic sheet 8 has an adequate slip resistance value both when wet and dry. This may be achieved by applying an over laminate film to the upper surface.

It has been found that a suitable graphic sheet is a Scotchal™ film 3662-10 (for use in screen printing) or a Scotchal™ film 8662-10 ES (for use in electrostatic printing of the graphic), both of which are supplied by the 3M company. A suitable
overlaminate is the Scotchal™ overlaminate film 3647, also supplied by the 3M company. The overlaminate film 3647 has suitable skid resistance values of SRV-49 (dry surface) and SRV-40 (wet surface), as set by the EU standards in pr EN 1341 and pr EN 1342 for outdoor pedestrian surfaces. The raised chequered surface 5 also complies with EU anti-skid requirements. The standard EN 124:1994 requires that cast iron and steel upper surfaces of manhole tops shall have a raised pattern; the height of the raised pattern, depending on classification, being between 2 to 6 mm or 3 to 8 mm.

The raised edge or rim 9 reduces the risk of premature lifting of the graphic sheet 8 due to foot traffic. The raised edge 9 also minimises the risk of unauthorised removal of the graphic sheet 8 by hand. As the graphic sheet 8 is cut to fit snugly within the raised edge 9, it would require a knife or similar device to lift the graphic sheet 8 from the frame.

It is possible to periodically change the graphic sheet 8. Firstly, an edge of the adhered graphic sheet 8 is detached from the planar surface 7 by inserting the blade of a scraper or putty knife under the edge portion. The sheet is then lifted by pulling the detached edge away from the surface at an angle of about 135°, using a smooth even tension. The sheet 8, when removed, is discarded. Some adhesive residue may remain on the planar surface. 7. This is removed, and the manhole cover is cleaned, by shot blasting. The planar surface 7 is then masked, and the manhole cover 1, is repainted with black paint and a new graphic sheet 8 is applied, as described above.

The manhole cover 1 may be of any desired shape, e.g. square, rectangular, circular or oblong. It may also be of any desired size. The manhole cover is designed to fit within a complementary frame which is fixed in the ground.

A second embodiment of a footway product according to the invention is shown in Figures 3 and 4 of the drawings. This comprises a self-levelling frame 10 which is adapted to receive a manhole cover e.g. of the kind as described with reference to Figure 1 above.

The frame 10 is intended to support a self-level cover. In use the frame is embedded into the top surface of the road. The frame 10 comprises a flange 22 and an annular wall 21. Thus, the frame is embedded into the road such that the flange 22 sits substantially flush with the road surface and the annular wall 21 extends down into the chamber. The self-level cover 1 and frame 10 are compacted into place on the hot asphalt when the road surface is being set. The frame and cover thus level themselves automatically to the road surface.

The frame 10 comprises a solid base portion 12 having an upper surface 13. A perimeter area of the frame is provided with a plurality of raised projections or protuberances 15, of the kind described above with reference to Figure 1, for the purpose of providing a non-slip surface. A central area of the upper surface 13 is provided with a raised portion 16. The raised portion has a planar surface 17 which is adapted to receive a graphic sheet 8. The planar surface 17 is surrounded by a frame comprising a raised edge or rim 19. Thus, the construction of the raised surface portion and rim is substantially similar to that described above with reference to Fig. I5 and the dimensions may be similar. The graphic sheet 8 is attached, as described above with reference to Figure 1. As with the embodiment of Figure 1 a continuous surface is maintained across the tops of the raised projections 15, the raised rim 19 and the upper surface of the graphic sheet 8 to avoid a trip hazard.

The frame 10 may be cast from metal, e.g. iron, as described below under "casting method".

Referring now to Figures 5 and 6 of the drawings, there is shown a further embodiment of a self-levelling frame for a manhole cover. This is a variation of the frame of Figures 3 and 4, and like reference numbers denote like parts.

In this embodiment the frame does not have a raised portion, but instead the planar surface 17 is formed on the upper surface 13 of the frame. The raised edge or rim 19 defines a recess 20 in which the graphic sheet 8 is positioned. The graphic sheet 8 is adhered to the surface 17 as described above. In this embodiment there are no upwardly directed projections, and the desired non-slip properties are achieved by the slip resistant characteristics of the sheet 8 and the adjoining top surface of the rim 19.

Casting Method

The method by which a manhole cover, or frame, of the invention is cast may be as follows:
An aluminium pattern is produced, to a near exact reproduction of the finished casting. The pattern is sectioned to form a drag and a cope pattern which is then attached to its own tooling plates.

The tooling plates in turn are secured to respective bolster boxes. The bolster box, to which the cope pattern is secured to, moves under the moulding machine to a predetermined position. The cope moulding box moves over the cope pattern, similar to a picture frame surrounding a picture. The tool is then lifted into position to sit under the moulding box.

At this stage sand is caused to fall from an overhead hopper to back fill the moulding box. Once the correct quantity of sand is in the moulding box, it is tightly filled into place in the box and around the pattern under a high pressure through the operation of an air operated squeeze head.

Once the sand mould is created, the tool retracts from the moulding box leaving behind a cavity from the pattern in sand within the moulding box. The cope moulding box then moves to the next operation in the process and the same process is carried out to form the cavity of the drag pattern in the drag moulding box.

The cope moulding box containing the cavity created by the cope pattern is rotated through 180°, and is then seated directly on top of the drag moulding box. The correct alignment of both boxes to allow both patterns to mate at the correct parting face is achieved through the alignment of a series of dowels and bushes in both boxes.
Hereinafter, the cope and drag moulding boxes are referred to as "the moulding box".

The Melt Process is the next stage in the process. This process involves the melting down of the charge (raw materials) to a molten iron. The charge consists of scrap metal, pig iron and ferro alloy additives. All materials are carefully weighed and placed into a furnace for melting and homogenisation.

Once the charge is fully melted down and has reached the desired pouring temperature of 15000C, magnesium is added to ladle and is moved into position in front of the furnace, the pouring process begins. As the molten iron is poured from the furnace into the ladle it reacts with the magnesium, to form ductile iron. Prior to pouring of the ladle into the moulding box, any additional slag is removed from the ladle.

Molten Iron is poured from the ladle into a pouring cup on the mould, which controls its delivery to the rest of the mould. From the pouring cup the metal travels down the sprue, then along horizontal channels called runners and finally through controlled entrances, called gates into the mould cavity.

The overall network of channels used to deliver the molten metal from outside the mould to the mould cavity is called the gating system. This gating system is formed as part of the creation of the cavity created by the patterns earlier in the process.

The next stage of the process is called "solidification". The molten iron poured into the mould is allowed to solidify into the desired final shape. The period of time required for solidification is dependent on product type i.e. the amount of molten iron used in the production of the casting.

Once the solidification period is completed, the moulding box is lifted into position above a shakeout deck. The mould including the casting is pushed out of the moulding box by a ram and dropped onto the shakeout deck. This deck acts as a vibrating bed onto which the casting moves along, removing any sand attached to it. The gating system and casting is then lifted off the shakeout deck. The moulding sand returns to the sand plant by conveyor for recycling.

The casting is moved to the finishing area and placed into a shot-blasting machine for a 5-minute cycle where any additional sand is removed and the casting is then cleaned.

The words "comprises/comprising" and the words "having/including" when used herein with reference to the present invention are used to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.

From the foregoing, it will be apparent that numerous modifications and variations can be effected without departing from the true spirit and scope of the novel concept of the present invention. It will be appreciated that the present disclosure is intended to set forth the exemplifications of the invention which are not intended to limit the invention to the specific embodiments illustrated. The disclosure is intended to cover by the appended claims all such modifications as fall within the scope of the claims.

Where technical features mentioned in any claim are followed by reference signs, these reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the scope of each element identified by way of example by such reference signs.