GB2577152A

GB2577152A - Improved transport equipment

Info

Publication number: GB2577152A
Application number: GB1908226.2A
Authority: GB
Inventors: Glass Andrew; Windley Andrew; Francis Sanders Stephen; Johnstone Clive
Original assignee: JSP Ltd
Current assignee: JSP Ltd
Priority date: 2018-09-11
Filing date: 2019-06-10
Publication date: 2020-03-18
Anticipated expiration: 2039-06-10
Also published as: GB2577152B; IE20190151A1; IE87229B1; GB201814746D0; GB201908226D0

Abstract

A method of manufacturing an item of traffic equipment 20, comprises moulding a main body from an elastomeric material at an elevated temperature; removing the main body from the mould, the main body is at an intermediate temperature between the elevated moulding temperature and ambient temperature; placing a pre-formed piece of a thermoplastic paint sheet material in contact with a surface of the main body and applying heat to an outward surface of the sheet material to cause bonding between the contacting surfaces of the pre-formed piece of sheet material and the main body. An item of traffic equipment, including a main body having a relief pattern on its outer surface defining at least one recess 26 is also provided. The thermoplastic paint sheet material may include reflective beads integrated therein. The step of applying heat may include using a heat gun. The item may be a speed ramp, traffic cone, road traffic barrier, or railway sleeper.

Description

(71) Applicant(s):

JSP Limited (Incorporated in the United Kingdom)

Worsham Mill, Minster Lovell, OXFORD, 0X29 OTA, United Kingdom (56) Documents Cited:

GB 0689791 A

WO 2005/017263 A1

US 5013181 A https://www.hilltop-products.co.uk/news/hot-airplastic-welding-guide (58) Field of Search:

INT CL B29C, E01F

Other: WPI, EPODOC, Patent Fulltext (72) Inventor(s):

Andrew Glass

Andrew Windley

Stephen Francis Sanders Clive Johnstone (74) Agent and/or Address for Service: Wynne-Jones IP Limited 2nd Floor, 5210 Valiant Court, Gloucester Business Park, Gloucester, Gloucestershire, GL3 4FE, United Kingdom (54) Title of the Invention: Improved transport equipment

Abstract Title: A method of manufacturing an item of traffic equipment (57) A method of manufacturing an item of traffic equipment 20, comprises moulding a main body from an elastomeric material at an elevated temperature; removing the main body from the mould, the main body is at an intermediate temperature between the elevated moulding temperature and ambient temperature; placing a pre-formed piece of a thermoplastic paint sheet material in contact with a surface of the main body and applying heat to an outward surface of the sheet material to cause bonding between the contacting surfaces of the pre-formed piece of sheet material and the main body. An item of traffic equipment, including a main body having a relief pattern on its outer surface defining at least one recess 26 is also provided. The thermoplastic paint sheet material may include reflective beads integrated therein. The step of applying heat may include using a heat gun. The item may be a speed ramp, traffic cone, road traffic barrier, or railway sleeper.

Figure 2

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Figure 5

Figure 6

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Figure 7a

Figure 7b

Figure 7c

Figure 7d

103

Figure 8a

110

Figure 8b

Description [0001] Title: IMPROVED TRANSPORT EQUIPMENT

Technical Field [0002] This invention relates generally to improved transport equipment and, more particularly, to a method of manufacturing an item of transport equipment, such as a speed ramp, traffic cone, road traffic barrier, or railway sleeper, and an item of such transport equipment manufactured by said method.

Background Art [0003] Many different items of temporary and semi-permanent (although sometimes long term) transport equipment exist which are formed of a dense compression moulded material, such as rubber. For example, rubber speed ramps are known for temporary and long-term placement on roads, such speed ramps having a primary purpose of reducing traffic speed to a safe level, for example, at locations where road or construction works are taking place or on access roads to residential or commercial construction sites. WO 2005/017263 A (AVERY DENNISON CORPORATION) 24/02/2005 discloses a pavement marker including a base and at least one lens with retroreflective areas aligned to reflect headlights back toward a vehicle for producing a night-time signal. The lens and/or the base are formed from resins that include a fluorescent material. At least a portion of the lens is free of the retroreflective areas to that the fluorescent material of the lens and/or the base produces a daytime signal emitted from or through the lens. WO 2004/106636 A (AVERY DENNISON CORPORATION) 09/12/2004 discloses a surfacemounted pavement marker for secure attachment to a pavement surface by adhesive. The bottom surface of the pavement marker is divided into sectors, and a parallel array of grooves is formed in each sector. The grooves in each array are angularly aligned to the grooves in adjacent arrays. Additionally, each groove extends continuously from its inner end to the outer periphery of the pavement marker. US 4232979 A (AMERACE CORPORATION) 11/11/1980 discloses a pavement marker for engagement with an underlying roadway for providing a marking visible from an oncoming vehicle on the roadway surface. The pavement marker comprises a lens member of light-transmitting synthetic resin including a front face having a light receiving and refracting portion adapted to be inclined at an angle of at least 15 degrees and a rear face having reflex reflective means for reflecting light transmitted through the light receiving and refracting portion back to the source. In one embodiment, the pavement marker has an abrasion-limiting glass sheet having a thickness no greater than about 15 mils fixedly disposed on the light receiving and refracting portion and preferably under compression throughout the expected temperature range to which the pavement marker is exposed in use. In another embodiment, abrasion-limiting members are raised above the light receiving and refracting portion.

[0004] Such speed ramps are usually of dense rubber compression moulded formation, for example, using recycled PVC which is more cost-effective and environmentally friendly. The shape and pattern formed in the mould tool is often the nearly-final product. The ramp is usually configured to be bolted into the surface ofthe road, and often has an internal (longitudinal) channel for running thick cables through, the main body of the ramp thus providing protection therefor, particularly at locations where power generators for machinery and other facilities are needed close to public highways, as traffic needs to pass through the area without damaging the cables.

[0005] In other situations, these types of speed ramps provide a temporary or longer term speed restriction solution in public places, such as access roads into car parks, where the proprietor may not wish to invest in permanent, but more expensive, tarmac or concrete speed ramp alternatives. In general, and as intimated above, hard rubber speed ramps have a low to medium durability in terms of friction wear and weathering and thus have a shorter lifecycle and require replacing periodically, depending on the location and degree of usage.

[0006] Referring to Figure 1 of the drawings, a typical rubber speed ramp assembly comprises one or more elongate ramp portions 10 having a generally rectangular base and a rounded, convex upper (or operable) surface. The base has a longitudinal channel 12 running through it, all the way along its length, to receive cables therein. At one end, there is provided a pair of connecting members or locating lugs 14 and, at the longitudinally opposing end, there is provided a pair of corresponding recesses (not shown) configured to receive the locating lugs of another ramp portion so that a plurality of ramp portions can be connected together (length-wise), to form the required structure. End caps 16, having a generally semi-circular base and the same rounded operable surface as the elongate ramp portions 10, can be connected at each end of the line of ramp portions to ‘complete’ the structure. The straight edge of the end cap 16 is provided with, either, a pair of the above-mentioned locating lugs or a pair of the above-mentioned corresponding recesses, so that it can be connected to an end of a respective ramp portion. Each of the ramp portions 10 and end caps 16 has bolt holes 18 for receiving respective bolts to enable them to be bolted onto a road (or similar) surface.

[0007] It can be seen that such speed ramps, so constructed, have a simple overall shape and cross-section, and a range of height/depth options are available that can be selected depending on speed restriction requirements. They usually have a relatively low level, distinctive surface pattern, and some have small reflective pieces slotted into recesses in the body of the ramp, which (in use) are actuated by vehicle headlamps to improve the visibility of the speed ramps to drivers at night. To the same end, some of the centre ramp portions and/or end caps may be painted with yellow paint on the basis that yellow may be easier to see at night than the usual black.

[0008] However, the issue remains that these types of speed ramps are difficult to see, especially at night, thus causing drivers to drive over them too fast, potentially leading to damage to the vehicle and/or loss of control and, therefore, potentially decreasing safety, rather than increasing as intended. This may be further exacerbated over time, as the yellow paint starts to wear off and/or the reflective pieces become dirty and/or damaged/dislodged overtime.

[0009] Some or all of these issues arise in relation to other types of transport equipment, such as traffic cones, road traffic barriers, and railway sleepers, and it would therefore be desirable to provide an item of transport equipment having improved visibility characteristics which do not deteriorate significantly over time.

[0010] The present invention seeks to address at least some of the issues described above.

Summary of Invention [0011] The present invention provides a method of manufacturing an item of traffic equipment, comprising:

- moulding a main body from an elastomeric material in a mould at an elevated temperature;

- removing the main body from the mould wherein the main body is at an intermediate temperature between the elevated moulding temperature and ambient temperature; and

- placing a pre-formed piece of a thermoplastic paint sheet material in contact with a surface of the main body at the intermediate temperature; and applying heat to an outward facing surface of the pre-formed piece of thermoplastic paint sheet material so as to cause bonding between the contacting surfaces of the pre-formed piece of thermoplastic paint sheet material and the main body.

[0012] The elevated temperature can be above 150°C, for example about 160 °C. [0013] The intermediate temperature can be above 50°C, for example up to 65 ⁰C.

[0014] The step of applying heat to an outward-facing surface of the pre-formed piece of thermoplastic paint sheet material can raise the temperature at the contacting surfaces to a temperature between the intermediate temperature and the elevated temperature.

[0015] The thermoplastic paint sheet material can have a softening point between 65 and 130°C.

[0016] The method can further comprise moulding the main body to have a relief pattern on its outer surface defining at least one recess, wherein the preformed piece of thermoplastic paint sheet material is of substantially the same shape and size as the at least one recess so as to fit within the at least one recess.

[0017] Such a main body can have multiple recesses. As such, the method can further include the step of forming a plurality of pre-formed pieces by cutting or otherwise separating a plurality of segments from a larger sheet of thermoplastic paint sheet material to respective recesses in the surface ofthe main body.

[0018] The pre-formed piece of thermoplastic paint sheet material can have reflective beads integrated therein.

[0019] The elastomeric material can be PVC. Furthermore, the elastomeric material can be recycled PVC, and the thermoplastic paint sheet material can have a bonding temperature of around 150°C with the moulded elastomeric material.

[0020] The method can further comprise applying heat to the outward facing surface of said pre-formed piece of thermoplastic paint sheet material for less than 1 minute, for 10 - 40 seconds, or for 20 - 30 seconds.

[0021] The method can further comprise applying heat to the outward facing surface so as to raise the temperature ofthe outward facing surface to a maximum of around 600°C and to raise the temperature of the surface contacting the main body to a maximum of around 120°C and no more than around 130°C.

[0022] The method of the invention can comprise a method of manufacturing the item of traffic equipment having a main body comprising the steps of:

• providing or obtaining a mould defining a shape of said main body;

• using said mould in a compression moulding operation, using a dense rubber or rubber-like material, to form said main body;

• providing or obtaining at least one pre-formed piece of solidified thermoplastic paint;

• substantially immediately upon removal of said main body from said mould, following said compression moulding operation, placing said pre-formed piece of thermoplastic paint on a surface of said main body; and • subsequently, applying heat to the outward facing surface of said preformed piece of thermoplastic paint so as to cause bonding between the abutting surfaces of the pre-formed piece of thermoplastic paint and said main body.

[0023] The main body, once formed using said mould, can have a relief pattern on its outer surface. Such a relief pattern can define at least one recessed shape and, optionally, the pre-formed piece of thermoplastic material can be of substantially the same shape as said recessed shape, and configured to be located therein.

[0024] The pre-formed piece of thermoplastic can comprise a portion of solidified thermoplastic paint. Indeed, the pre-formed piece of thermoplastic material can comprise a portion of solidified reflective thermoplastic paint material. The pre-formed piece of solidified thermoplastic paint can have reflective beads integrated therein.

[0025] The method can include the steps of providing a thermoplastic paint in liquid form, configuring the thermoplastic paint as a layer of a predetermined depth defining a sheet-like shape, and allowing the thermoplastic paint to cool and solidify to form a sheet. The method can further include the step of scattering a plurality of reflective beads, for example, Soda Lime glass beads, over the surface of the thermoplastic paint before allowing it to cool and solidify to form said sheet, so as to further contribute to the retro-reflectivity and/or grip properties of the sheet when in use on a speed ramp. The glass beads can have a refractive index in the range 1.45 - 1.55. The method can further include the step of forming a plurality of said pre-formed pieces of thermoplastic material by cutting, or otherwise defining in, said sheet of thermoplastic paint, a plurality of removable segments to match a respective plurality of recessed shapes formed on the surface of said main body.

[0026] The reflective beads can comprise glass beads; and the thermoplastic paint can be yellow.

[0027] The thermoplastic paint can have a softening point between 65 and 130°C. The thermoplastic paint can also have a softening point between 70 and 90°C, and can have a flashpoint greater than 230°C.

[0028] The step of applying heat to the outward facing surface of the pre-formed piece of thermoplastic paint can comprise using a heat gun to apply said heat thereto. Such a step can further comprise using said heat gun to apply heat to said outward facing surface of said pre-formed piece of thermoplastic paint for 10 - 40 seconds or 20-30 seconds.

[0029] The pre-formed piece of thermoplastic material can have a bonding temperature of between 130°C and 170°C, for example, around 150°C (e.g. wherein the main body is formed of moulded PVC), at which bonding occurs between the above-mentioned abutting surfaces. The pre-formed piece of thermoplastic paint can be placed on said surface of said main body substantially immediately after its removal from said mould, such that its surface is still at an elevated temperature, for example around 65°C. Thus if the bonding temperature of the thermoplastic paint is around 150°C, bonding between the above-mentioned abutting surfaces will commence when the pre-formed piece of thermoplastic paint has been heated, via the outward facing surface, to a lower temperature, e.g. around 120°C. This is advantageous because heating the pre-formed piece of thermoplastic paint to a higher temperature, >130°C for a prolonged period may damage the thermoplastic structure and/or the surface of the main body immediately adjacent to the pre-formed piece of thermoplastic paint. By utilising the temperature of the main body as it is removed from the mould and carefully focussing heat at the outward facing surface of the pre-formed piece of thermoplastic paint for a time just sufficient to cause the abutting surfaces (together) to reach the bonding temperature, the bonding temperature can be achieved by heating the pre-formed piece of thermoplastic paint to a temperature lower than the bonding temperature, and the potential for such damage is minimised.

[0030] The rubber material can comprise recycled PVC, and the main body can be formed by injection moulding, although other processes for forming the main body can be used, e.g. compression moulding.

[0031] The invention extends to an item of traffic equipment manufactured by a method according to any of the steps described above.

[0032] The invention also provides an item of traffic equipment comprising:

- a main body formed from a moulded elastomeric material having a relief pattern on its outer surface defining at least one recess; and

- a pre-formed piece of thermoplastic paint sheet material of substantially the same shape and size as the at least one recess fitted within the at least one recess;

- wherein the a pre-formed piece of thermoplastic paint sheet material is directly bonded to the main body.

[0033] The main body can have multiple recesses, each including one of a plurality of pre-formed pieces by cut or otherwise separated from a larger sheet of thermoplastic paint sheet.

[0034] The pre-formed piece of thermoplastic paint sheet material has reflective beads integrated therein.

[0035] The elastomeric material can be PVC.

[0036] The item of traffic equipment can comprise a speed ramp or railway equipment (e.g. a railway sleeper).

[0037] The speed ramp can comprise a main body, injection or compression moulded using a dense rubber or rubber-like material, and at least one pre-formed piece of reflective thermoplastic paint bonded on an operable surface of said main body.

[0038] An outer operable surface of the speed ramp can be provided with a relief pattern defining at least one recessed portion, said pre-formed piece of thermoplastic paint being located within the perimeter of said recessed portion. At least the outer surface at the leading edge of the speed ramp can be provided with a relief pattern defining at least one recessed portion, with a pre-formed piece of thermoplastic material being located in the or each recessed portion.

[0039] A railway sleeper can comprise a main body compression moulded using a dense rubber or rubber-like material, and at least one pre-formed piece of reflective thermoplastic paint bonded on an operable surface of said main body.

Brief Description of Drawings [0040] Figure 1 is an exploded illustration of a moulded rubber speed ramp. [0041] Figure 2 is a schematic perspective view of a first speed ramp.

[0042] Figure 3 is a schematic perspective view of a ramp portion and end cap of the speed ramp of Figure 2.

[0043] Figure 4 is a schematic side view of the speed ramp of Figure 2. [0044] Figure 5 is a schematic plan view of the speed ramp of Figure 2.

[0045] Figure 6 is a schematic bottom view of the speed ramp of Figure 2.

[0046] Figures 7a - 7d show different shapes of thermoplastic paint pieces used in the speed ramp of Figure 2.

[0047] Figures 8a - 8b show schematic perspective views of another speed ramp in a first configuration and a second configuration.

Description of Embodiments [0048] A core advantage of the present invention over the known prior art is to provide an item of traffic equipment of dense rubber or rubber-like material, on which a significantly larger surface area of its body can be provided with reflective means, so as to significantly improve its visibility in low light conditions.

[0049] This, and other, advantages are attained by using reflective thermoplastic paint segments or portions directly applied to the surface of the body and bonded thereto.

[0050] Thermoplastic paint is known for use in road marking, and preformed thermoplastic road markings are known whereby a sheet of pre-formed thermoplastic “paint” is cut into shapes by the manufacturer, ready to position onto an asphalt or concrete pavement surface. Preformed thermoplastic markings of this type are typically put in place on the road surface and then applied using a propane heat torch. Reflective thermoplastic road line marking tape is also known, and available in a variety of colours. Once again, such tape can be placed as required on the road or pavement surface, and then applied using a gas torch to melt the tape onto the road/pavement surface. Some thermoplastic tapes of this type may have integrated glass beads to improve the reflectiveness of the tape. Preformed thermoplastic tape of these types must be applied at between 190 and 200°C to ensure good adhesion. This means that the gas torch, which burns at temperatures in excess of 2000°C, must be applied over the tape for a sufficient period of time for the thermoplastic to reach the desired melting temperature and cause adhesion. It is for this reason that they should not be used on new asphalt until the surface has settled for a period of time, as this process is likely to soften the new asphalt beneath the tape. If lower temperatures are used, known preformed thermoplastic tapes could not be heated to a sufficiently high temperature to adhere sufficiently strongly.

[0051] Thus, whilst such preformed thermoplastic tapes may be highly effective for providing markings on surfaces such as roads and pavements, which can withstand very high temperatures without deformation, they are unsuitable for use on materials which cannot withstand such temperatures, and it has not, therefore, previously been considered to utilise preformed thermoplastic tape or sheet on anything other than roads, pavements and similar substrates.

[0052] The present invention, on the other hand, seeks to address the principal problem of how to significantly increase the visibility of an item of traffic equipment, such as a speed ramp, by increasing the surface area carrying reflective elements using segments or portions of preformed thermoplastic paint bonded to the surface of the equipment.

[0053] A problem addressed by the present invention is, therefore, how to provide a preformed thermoplastic tape or sheet that can be used to form a sufficiently strong bond with a substrate formed of, for example, a dense rubber injection moulding formation, which cannot withstand temperatures above, say, 60-70°C or so for any significant length of time, without deformation.

[0054] In order to achieve this object, the present invention seeks to provide a reflective thermoplastic paint that utilises the softening point of the material (rather than its, higher, melting point) to bond (rather than adhere) the thermoplastic paint to the substrate below. As an example, a thermoplastic paint having a softening point of 65-130°C and a relatively high flashpoint, for example, >230°C, is proposed. Bonding between the thermoplastic paint and a rubber substrate beneath occurs at a much lower temperature than that required to melt a thermoplastic tape to a road or pavement. A pre-formed piece of thermoplastic material having a bonding temperature of around 150 °C is considered suitable. This means that the thermoplastic element does not need to be heated to the high temperature required for road markings, and the method described herein can be performed using a focussed heat source at a relatively high temperature for a shorter period of time than required by prior art application processes, thus ensuring that the temperature of the underlying substrate is not raised enough during the application process to damage it, nor is the thermoplastic structure damaged during the process.

[0055] These specifications can be achieved with a number of different specific compositions of components but, in general, the bespoke reflective thermoplastic composition used in the invention comprises synthetic resin, highly refined mineral oil, aggregates, extenders, polymers, solid pigments and reflective glass beads, and the approximate proportions of a thermoplastic material used are set out below, providing a thermoplastic composition with a softening point of around 80°C and a bonding temperature of around 150°C:

[0056]

Table 1

Ingredient	CAS/EC No.	Classification (EC) 1272/2008	Weight %
Calcium Magnesium Carbonate	CAS 16389-88-1 EC-No. 240-440-2	Not Classified	30-60%

Soda Lime Glass Beads	CAS 65997-17-3 EC-No. 266-046-0	Not Classified	0-40%
Resin acids and Rosin acids, fumarated, esters with pentaerythritol	CAS 94581-15-4 EC-No. 305-514-1	C1: H 317 Allergic Skin reaction H 319 Eye Irritation. H 413 Aquatic Hazard	0-20%
Polyamide resin		Not Classified	0-10%
Titanium Dioxide	CAS 13463-67-7 EC No. 236-675-5	Not Classified	0-10%
1,2- Benzenedicarboxylic acid,di-C8-10branched alkyl esters	CAS 68515-48-0 EC No. 271-090-9	Not Classified	0-5%
Polymer		Not Classified	0-5%
Pigment		Not Classified	0-5%

[0057] The exact properties of ingredients within the material, and the ratio of characteristics, can be varied more or less in relation to:

• visibility/reflective performance - distance of visibility in varying light levels • anti-skid/grip performance - engagement with rubber of tyres, friction level, grip or slip when wet • Frictional/Tyre-contact durability performance - e.g. to withstand around 1,000,000 passes of vehicles.

• UV exposure/weathering durability performance - no loss of colour or fading, typical range of temperatures: -10°C to +50°C, sunlight, rain, snow [0058] The component having the primary influence on the softening/melting point and the bonding temperature ofthe composition is the Titanium Dioxide, and this can be varied in accordance with requirements and to accurately meet the required balance between the bonding temperature at the abutting surfaces between the pre-formed piece of thermoplastic paint and the main body, as will be described in more detail hereinafter.

[0059] In the composition described above, the glass bead content governs the retro-reflectivity of the material. The retro-reflectivity of the material might be minimised at 15-20%, optimised at around 30% and maximised at 50%. However, the beads are mixed into the composition, such that the material may need to be worn down by weather and traffic before their maximum effect can be achieved. Bearing in mind that the purpose of the speed ramp is to restrict traffic speed, the thermoplastic elements may be protected to some extent. Thus, the retro-reflectivity of the thermoplastic elements is likely to be governed primarily by the glass beads on the surface. This can then be optimised by dropping a quantity of glass beads onto the surface of the thermoplastic before it sets, thereby increasing the surface area covered by the glass beads and, in turn, the retro-reflectivity of the resultant thermoplastic sheet. The concentration of beads dropped onto the surface of the thermoplastic can also be used to determine the eventual durability and grip characteristics of the reflective elements. The glass beads can, for example, comprise Soda Lime beads having a refractive index in the range 1.45-1.55 (e.g. 1.5-1.53).

[0060] The thermoplastic sheet used to form the reflective elements can be yellow, to optimise retro-reflectivity, but other colours can alternatively or additionally be considered, depending on their intended use.

[0061] A large sheet of reflective thermoplastic material of the type described above can be preformed, and then specific shapes can be pre-cut so that, during a manufacturing process according to the invention, each reflective element can be easily removed from the sheet for application at the appropriate location on the body of the item of traffic equipment being manufactured.

[0062] Referring now to Figure 2 of the drawings, a speed ramp 20 comprises one or more ramp portions 22. Each ramp portion 22 comprises a generally rectangular base, as before and a rounded convex upper or operable surface. The main body of the ramp portion is formed of dense injection moulded recycled PVC and the upper surface of the moulded body has a distinctive pattern defining a plurality of diamond and triangular recessed portions 24. There are other methods of forming the main body, for example, compression moulding.

[0063] As a step of manufacturing the item of traffic, a thermoplastic sheet, of the type described above, can be provided. The sheet can have formed therein, pre-cut segments corresponding to the recessed portions in the moulded body. Immediately following the injection moulding process for moulding the body of a ramp portion 22, and whilst its surface is still at an elevated temperature, the pre-cut segments can be removed from the thermoplastic sheet and bonded in the recessed portions in a method described hereinafter.

[0064] It will be apparent that the visibility of the leading edge (see Figure 4) of the speed ramp is of important, and one or more 26 of the recessed portions may be left without a reflective thermoplastic insert, to allow (for example) a company logo or other identifying mark to be moulded or otherwise provided therein. However, in cases in which it is useful to maximise the surface area covered by the reflective inserts, the central recesses 26 can also be provided with reflective thermoplastic inserts in the same manner.

[0065] Referring back to Figure 2 of the drawings, the speed ramp 20 can further comprise a pair of end caps 28, one at each end of an elongate ramp portion 22 or, indeed, a structure comprising a plurality of such ramp portions connected together. It can be seen, from Figure 3 of the drawings, that each ramp portion 22 is provided, at each end, with a locating lug 30 and a recess 32 which allows a number of ramp portions 22 to be connected together lengthwise. Each end cap 28 comprises a generally semi-circular base and a rounded, convex upper or operable surface to match that of the associated ramp portions 22. The main body of each end cap 28 is formed of dense injection moulded recycled PVC and the upper surface of the moulded body has (at least) a triangular recessed portion 34. As with the above-described ramp portion, a pre-cut segment of reflective thermoplastic paint can be bonded into the recessed portion 34 in the manner to be described hereinafter.

[0066] Referring to Figure 5 of the drawings, in its assembled state, a speed ramp 20 comprising a single ramp portion 22 and a pair of end caps 28 of the type described above can be seen to provide a distinctive pattern of reflective portions along the edges and close to the ends. Referring to Figure 6 of the drawings, as before, the base of the ramp portion 22 and each end cap 28 is provided with a longitudinal channel 36 to accommodate cables, in use, if required; and, referring back to Figure 3 of the drawings, as before, bolt holes 38 are provided laterally through the thickness of the bodies of both the ramp portion 22 and the end caps 28 to enable the assembled speed ramp 20 (Figures 2 and 5, for example) to be bolted onto a road or other surface.

[0067] The table below indicates the surface area of the speed ramp covered by each segment type, and defines a number of exemplary configurations of reflective thermoplastic segments that could be utilised.

[0068]

Table 2

Config.	Central	Central	Central	End Cap	Top Profile
No.	Section	Section	Section	Section	Total
	Isosceles	Isosceles	Rhombus	Isosceles	Surface
	Triangle	Triangle	(Diamond)	Triangle	Area
	Type (1)	Type (2)	Fig. 7c	Type (2)	Coverage of
	Fig. 7a	Fig. 7b	Qty 2 per	Fig. 7d	Inserted
	Qty 6 per	Qty 2 per	Section	Qty 1 per End	Element
	Section	Section	Area =	Cap	material
	Area = 5720mm²	Area = 5390mm²	11440mm²	Area = 10,780mm²	technology
1	Active (Area 34,320mm²)	Active (Area 10,780mm²)	Active (Area 22,880mm²)	Active (Area 10,780mm²)	26%
2	Active (Area 34,320mm²)	Active (Area 10,780mm²)	Active (Area 22,880mm²)	Blank	22%
3	Active (Area 34,320mm²)	Active (Area 10,780mm²)	Blank	Blank	15%
4	Active (Area 34,320mm²)	Blank	Blank	Blank	11%
5	Active (Area 34,320mm²)	Active (Area 10,780mm²)	Blank	Active (Area 10,780mm²)	18%

[0069] As indicated (with reference to Figure 2 of the drawings), an assembled speed ramp has an operable surface area of 18% covered by reflective thermoplastic material (row no. 5). In the case where the two diamond shaped recesses 26 over the centre are also provided with reflective thermoplastic inserts, the operable surface area coverage can be increased to 26% (row no. 1). Other configurations are suggested in rows 2 to 4 of the illustrated table, giving an operable surface area coverage of between 11 and 22%, according to requirements. It will be appreciated that many different configurations of reflective thermoplastic inserts could be used, and the present invention is not intended to be in any way limited in this regard.

[0070] The shapes of the thermoplastic inserts described in the table above are shown in Figures 7a - 7d.

[0071] It can thus be seen that a significant proportion of the operable surface area of a speed ramp can be made highly visible by motorists in low level conditions. This level of reflective coverage has not been disclosed or suggested before, and is considered to contribute significantly to the visibility and, therefore, safety of a speed ramp. It has not previously been possible to bond reflective thermoplastic paint to a dense rubber compression moulded body and, therefore, significant innovative effort has been required by the inventors to devise a method that enables the features of the present invention to be realised.

[0072] A technical problem solved by the present invention is related to the strength of the bond between the reflective thermoplastic insert and the moulded body of an item of traffic equipment (e.g. a speed ramp). The body (e.g. ramp body) can be moulded from an elastomeric material (e.g. recycled PVC, which is inherently full of contaminants and of oily consistency). Furthermore, the thermoplastic paint cannot be melted onto the body (e.g. ramp body) to create a bond because if the moulded elastomeric material (e.g. PVC or recycled PVC) is exposed to a high temperature for the prolonged period of time to melt the thermoplastic material and cause it to “stick” to the body (e.g. ramp body), damage/deformation would be caused. A method of forming a bond between the reflective thermoplastic paint sheet material and the moulded body (e.g. moulded body of the speed ramp) will now be described in more detail. As a first step, a sheet of reflective thermoplastic material of the type described above can be formed or obtained, the sheet having pre-cut segments therein defining the shapes of the reflective portions on the finished body (e.g. speed ramp element) and matching recesses included in the moulded body. Wherein the moulded body has multiple recesses, a plurality of pre-formed pieces can be formed by cutting or otherwise separating a plurality of segments from a larger sheet of thermoplastic paint sheet material to respective recesses in the surface of the moulded body. The pre-formed piece(s) of thermoplastic paint sheet material can have reflective beads integrated therein.

[0073] The body (e.g. speed ramp element) is formed by a moulding process (e.g. injection moulding) using an elastomeric material (e.g. black recycled PVC material, which is considered a cost effective option within the scope of the current field of technology). The temperature inside the mould can be around 160°C, which is sufficient to melt PVC material for injection into the mould. The injection moulding process can take around 6 minutes. The main body can be moulded to have a relief pattern on its outer surface defining at least one recess, wherein the pre-formed piece of thermoplastic paint sheet material is of substantially the same shape and size as the at least one recess so as to fit within the at least one recess.

[0074] After moulding, the body is removed from the mould while it is at an intermediate temperature between the elevated moulding temperatures (i.e. the temperature at which the body is moulded) and the ambient temperature. The elevated temperature can be above 150°C and the intermediate temperature can be above 50°C. The surface temperature of the body, thus moulded, can be approximately 65°C as it comes out of the mould tool. At this point, at least one pre-formed piece of thermoplastic paint sheet material I reflective thermoplastic element is placed in contact with a surface of the body at the intermediate temperature and heat is applied to an outward facing surface of the pre-formed of thermoplastic paint sheet material so as to cause bonding between the contacting surfaces of the pre-formed piece of thermoplastic paint sheet material and the body. The application of heat can raise the temperature at the contacting surfaces to a temperature between the intermediate temperature and the elevated temperature. The heat can be applied for less than 1 minute, 10-40 seconds or 20-30 seconds for the abovedescribed bonding to occur. For example, the reflective thermoplastic element(s) can be substantially immediately placed in the respective recess(es) defined in the operable surface of the moulded body (e.g. moulded speed ramp element) and pressed down, such that the bonding process begins immediately between the abutting surface(s) of the pre-cut segment(s) and the moulded body. Then, for example, a heat gun can be used to complete the bonding process. Such a heat gun can be directed over the outward facing surface of each segment for 20-30 seconds so as to raise the temperature of the reflective thermoplastic at the outward facing surface to a maximum of 600°C, which can be sufficient to raise the temperature at the surface abutting the body (e.g. ramp body) to around 120°C and no more than around 130°C. The thermoplastic composition can have a bonding temperature with recycled PVC of around 150°C, and wherein the temperature at the surface of the body (e.g. ramp body) is already 65°C, this is sufficient to provide a strong bond.

[0075] A number of different means of heating the reflective thermoplastic segment can be used. For example, a heat gun (which emits a stream of hot air, heated by an element and propelled by a fan, via a nozzle) can be used for a number of reasons. Firstly, it can be very focused, such that it can be ensured that no heat is applied to the surrounding mould, which would otherwise damage it. Secondly, it is significantly safer and more practical than the propane (or similar gas) guns required to bond conventional thermoplastic tape to road surfaces.

[0076] Once the mould and reflective thermoplastic segments thereon have cooled and fully solidified, a high bond strength is completed.

[0077] The above-described process of applying and bonding the reflective thermoplastic segments to the moulded body can be performed manually, or some or all steps of the method could be automated, and the present invention is not necessarily intended to be limited in this regard.

[0078] The workable solution thus developed uses the raised surface temperature of the moulded body to reduce the temperature required at the abutting surface of the thermoplastic paint segment to meet the bonding temperature, so as to ensure the bond strength is sufficient and durable whilst minimising the risk of damage to the thermoplastic structure or the underlying moulded body (e.g. ramp body).

[0079] The resultant item of traffic equipment (e.g. speed ramp) provides visibility features across the entire upper surface of the product, where it matters most. The surface area covered by these visibility features is significant, with the individual inserts being relatively large in size (compared with, say, the inserted reflective pieces used in the prior art).

[0080] Vehicle tyres are in continuous and abrasive contact with the operable surface ofthe speed ramp. In prior art devices, this causes the surface of the speed ramp to become slippery over time, as well as contributing to its wear. In contrast, in the present invention, such continuous use actually increases the reflectivity of the inserts, as thermoplastic is worn away from embedded glass beads. The anti-skid properties of the speed ramp are maintained for a longer period of time, again (at least partly) due to the frictional contribution of the glass beads. Thus, the present invention provides a novel method of manufacture that enables moulded rubber items of traffic equipment, such as speed ramps or railway sleepers, to be provided with regions of reflective thermoplastic material in order to provide a predetermined proportion of reflective surface area. Such items of traffic equipment, thus manufactured, have significantly improved visibility and durability characteristics compared with known prior art solutions. An additional benefit of items of traffic equipment manufactured in accordance with a method ofthe invention, is the improved grip characteristics (which can be customised according to application and requirements) and the significantly reduced loss of grip over time.

[0081] Modifications and variations can be made without departing from the scope of the invention. For example, an alternative speed ramp is illustrated in Figures 8a and 48b of the drawings. In this case, the speed ramp comprises a ramp body 100 having a generally rectangular base and a rounded operable surface. The ramp body is, as before, formed of injection moulded rubber, with recesses 102 formed on the leading and trailing edges, and other relief pattern features 103 are also provided, as required, to contribute to its grip characteristics. A set of longitudinal channels 104 (three, in this specific case) are provided in the ‘upper’ surface of the ramp body 100. A planar cover 106 is hinged, longitudinally, so as to movable relative to the ‘upper’ surface of the ramp body 100 between a closed position in which it covers the channels 104, as shown in Figure 8a of the drawings, and an open position in which the channels 104 are exposed, as shown in Figure 8b of the drawings. The cover can, again, be formed of injection moulded rubber (e.g. Polypropylene co-polymer material) and provided, on its outer surface, with a relief pattern to contribute to the grip characteristics thereof. The outer surface of the cover 106 can be yellow (or other colour)to improve its visibility characteristics, and this colour can be formed in the polymer moulding process in a manner that will be known to a person skilled in the art. A hinge can be provided in the form of a hard polymer rod that passes through juxtaposed apertures on the edge of the cover and the main body, so as to connect the two elements together. Reflective thermoplastic inserts, of the type described above, are bonded within the recesses 102 formed on the leading and trailing edges of the ramp body 100, as before. A locating lug 108 and recess 110 is provided at each end of the ramp body 100 (adjacent the base) to enable a plurality of such ramp bodies to be connected together longitudinally.

Claims

Claim 1. A method of manufacturing an item of traffic equipment, comprising:

- moulding a main body from an elastomeric material in a mould at an elevated temperature;

- removing the main body from the mould wherein the main body is at an intermediate temperature between the elevated moulding temperature and ambient temperature;

- placing a pre-formed piece of a thermoplastic paint sheet material in contact with a surface of the main body at the intermediate temperature; and

- applying heat to an outward facing surface of the pre-formed piece of thermoplastic paint sheet material so as to cause bonding between the contacting surfaces of the pre-formed piece of thermoplastic paint sheet material and the main body.
Claim 2. A method as claimed in claim 1, wherein the elevated temperature is above 150°C.
Claim 3. A method as claimed in claim 1 or 2, wherein the intermediate temperature is above 50°C.
Claim 4. A method as claimed in claim 1,2, or 3, wherein the step of applying heat to an outward-facing surface of the pre-formed piece of thermoplastic paint sheet material raises the temperature at the contacting surfaces to a temperature between the intermediate temperature and the elevated temperature.
Claim 5. A method as claimed in any preceding claim, wherein the thermoplastic paint sheet material has a softening point between 65 and 130°C.
Claim 6. A method as claimed in any preceding claim, comprising moulding the main body to have a relief pattern on its outer surface defining at least one recess, wherein the pre-formed piece of thermoplastic paint sheet material is of substantially the same shape and size as the at least one recess so as to fit within the at least one recess.
Claim 7. A method as claimed in claim 6, wherein the main body has multiple recesses, the method including forming a plurality of pre-formed pieces by cutting or otherwise separating a plurality of segments from a larger sheet of thermoplastic paint sheet material to respective recesses in the surface of the main body.
Claim 8. A method as claimed in any preceding claim, wherein the pre-formed piece of thermoplastic paint sheet material has reflective beads integrated therein.
Claim 9. A method as claimed in any preceding claim, wherein the elastomeric material is PVC.
Claim 10. A method as claimed in claim 9, wherein the elastomeric material is recycled PVC, and the thermoplastic paint sheet material has a bonding temperature of around 150°C with the moulded elastomeric material.
Claim 11. A method as claimed in any preceding claim, comprising applying heat to the outward facing surface of said pre-formed piece of thermoplastic paint sheet material for less than 1 minute, 10-40 seconds, or 20 - 30 seconds.
Claim 12. A method as claimed in any preceding claim, comprising applying heat to the outward facing surface so as to raise the temperature of the outward facing surface to a maximum of around 600°C and to raise the temperature of the surface contacting the main body to a maximum of around 120°C and no more than around 130°C.
Claim 13. An item of traffic equipment, comprising:

- a main body formed from a moulded elastomeric material having a relief pattern on its outer surface defining at least one recess; and

- a pre-formed piece of thermoplastic paint sheet material of substantially the same shape and size as the at least one recess fitted within the at least one recess;

- wherein the a pre-formed piece of thermoplastic paint sheet material is directly bonded to the main body.
Claim 14. An item as claimed in claim 13, wherein the main body has multiple recesses, each including one of a plurality of pre-formed pieces by cut or otherwise separated from a larger sheet of thermoplastic paint sheet.
Claim 15. An item as claimed in claim 13 or 14, wherein the pre-formed piece of thermoplastic paint sheet material has reflective beads integrated therein.
Claim 16. An item as claimed in claim 13, 14, or 15, wherein the elastomeric material is PVC.
Claim 17. An item as claimed in any of claims 13-16, when manufactured by a method according to any of claims 1-12.
Claim 18. An item as claimed in any of claims 13-17, comprising a speed ramp or a railway sleeper.

Intellectual

Property

Office

Application No: GB1908226.2