ROADWAY MARKER POST

Abstract: A fiberglass reinforced resin roadway marker post (10) is moulded from a catalytic setting resin. The fibreglass is substantially unidirectional except for a very small amount of cross woven fibres used to maintain the greater portion of the fibres in their unidirectional configuration. The post (10) may be provided with a recess (15) for receiving a strip of reflective material and barbs (16) at its lower end.

Description: ROADWAY MARKER POST FIELD OF INVENTION This invention relates to roadway markers or guide posts and more particularly to resilient roadway markers which, when struck by a vehicle, give way without suffering impairing damage and which return to the upright position after the vehicle has passed. BACKGROUND ART Australian Patent 526,508 discloses a fibreglass roadway 10 marker which is capable of being driven into the ground when being installed. According to that specification, the structural requirements of resilience and elasticity are inconsistent with the longitudinal rigidity required to resist bending of the post as it is driven into the ground as 15 such longitudinal rigidity tends to prevent the post from yielding to lateral impact after it has been installed. The roadway marker disclosed in Australian specification 526,508 consists of a fibre-reinforced synthetic material which contains a combination of randomly oriented and 2.0 longitudinally oriented fibres imbedded in 20 to 40% by weight resin binder. The specification further discloses that at least 7% but not more than 60% of the fibres are randomly oriented to increase tensile strength (and hence transverse flexibility) 5 with the remainder of the fibres being longitudinally oriented to provide longitudinal rigidity. Prior art fibreglass roadway marker posts have been formed by a pultrusion process which restricts the outer surface to being part of the pigmented resin in which the fibreglass is embedded. Thus, the post tends to discolour quickly when exposed to sunlight for prolonged periods. Furthermore, such a process does not permit the formation of recesses in the marker for receiving strips of reflective material. DISCLOSURE OF INVENTION According to the present invention there is provided a roadway marker post comprising an elongated structure of fibreglass reinforced resin material characterised in that the resin is a catalytic setting resin and the fibres are substantially unidirectional. According to another aspect of the invention there is provided a method for manufacturing a roadway marker post comprising the steps of:- (i) forming a mould having a projection or a recess therein adapted to form a recess or projection in the finished roadway marker post, (ii) applying a gelcoat to the mould, (iii)adding fibreglass and a catalytic setting resin to the mould, and, (iv) pressing the components within the mould and retaining them in the compressed form until the resin has catalytically set. BRIEF DESCRIPTION OF THE DRAWINGS In order that the invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings in which:- Fig. 1 is a partly broken away, front elevational view of a raodway marker post according to one embodiment of the invention. Fig. 2 is a front elevational view of the upper portion of a modified roadway marker post. Fig. 3 is a cross-sectional view taken along lines A-A of Fig. 1, Fig. 4 is a schematic front elevational view of an undeformed roadway marker post, Fig. 5 is a schematic view similar to Fig. 4 but with the post deformed, and. Fig. 6 is a front elevational view of the top portion of a roadway marker post according to one embodiment of the invention and a jig for use in driving the post into the ground. DESCRIPTION OF PREFERRED EMBODIMENTS The general shape and configuration of a roadway marker post according to the invention is shown in Figs. 1 and 2. The post 10 is of arcuate cross-section and has an upper portion 11, a body portion 12 and a lower or leading portion 13. As can be seen in Fig. 1, the leading portion 13 of the post 10 is pointed to assist the driving of the post into the ground. The upper portion 11 of the post 10 may carry embossed markings 14 (see Fig. 2) or a recess 15 (see Fig. 1) for receiving a strip of reflector tape. Barbs 16 may be provided on the leading portion 13 to resist withdrawal of the post 10 from the ground. The post 10 consists of a fibreglass reinforced resin material in which the fibres are substantially unidirectionally located in a matrix of a catalytic setting - resin. In a preferred form of the invention, the resin consists of a base material of saturated and unsaturated dibasic acids, and a dihydric glycol. The base material is dissolved in the monomer solvent, styrene, making it fluid. According to the present invention, the resin is promoted by one or a combination of:- (i) di-methyl aniline (DMA) (ii) di-ethyl aniline (DEA) (iii)cobalt naphthenate (iv) cobalt octoate (v) 10% solution of DMA in styrene The catalyst added to the resin may be one of the following catalysts or a combination thereof:- (i) benzol peroxide (ii) methyl ethyl ketone peroxide (iii)LCR The abovementioned catalyst may include one or more of the following dilutents:- (a) ethyl acetate 20-75% (b) di-methyl phthalate 20-75% (c) di-allyl phthalate 20-75% (d) methanol 20-75% (e) isooctyl acetate 20-75% (f) styrene .25-20% (g) water Less than 2% One dilutent, or a combination of the dilutents, is used to adjust various requirements of concentration and of required cure time to form the fully cured resin. By varying the proportions of the components and by using acids and glycols, the properties of the finished polyester is altered as desired. The preferred glycols and acids for a finished composite resin are:- (i) neopentylglycolisophthalic polyester resin (ii) isσphthtalic polyester resin (iii)neopentylglycol orthophthalic resin ■ (iv) orthophthalic polyester resin As the abovementioned resins are not inherently flexible .25-75% by weight of a flexible resin is added. A particularly suitable flexible resin is RCL which is marketed by British Paints. Furthermore, fillers may be included in the amount from 10 to 150% of total weight of the composite resin. The filler can be selected from the group comprising:- (i) calcium carbonate (ii) alumina trihydrate (iii)asbestos flock (iv) zircon flour (v) Calindria 244 (vi) antimony trioxide A single filler, or a combination of fillers, may be used in different polyester composites to provide the optimum resin composites under different conditions. The fibreglass used in the roadway marker post is substantially unidirectional save for a very small amount of cross woven fibre used to maintain the greater majority of the fibres in their undirection configuration. The use of this type of glass (defined as 'S 1 glass and 'E' glass in the " form of scrimmed unidirectional glass) gives a very high modulus fibre and are often used in very high performance laminates associated with the aerospace industry. In a preferred form of the invention, the total resin component is present in an amount from 30 to 225% of the - weight of the fibreglass. Although the posts may be made from a wide variety of the above described materials, a preferred post is formed from a specially woven E type unidirectional glass in the form of a 4 inch scrimmed taped and a catalytic setting resin formed from:- a) isophthalc non-flexible resin b) RCL flexible resin (marketed by British Paints ) c) styrene as a thinner d) calcium carbonate as a filler. The amount of each component is varied according to the physical characteristics required of the marker post. However, those amount will be within the ranges identified above. The roadway marker may be formed in a 200-2,500 pounds per square inch cold/hot press machine. The unidirectional glass is placed into the mould at different pre-calculated sections of the mould to create different mechanics of the reinforcement. The changes the stress/strain characteristics of the reinforced plastic will be apparent from the following discussions which considers the schematic post shown in Fig. 4 (undeformed) and Fig. 5 (deformed) from the simple strength of materials viewpoint. When the unidirectional composite post having fibres 20 and matrix 21 as shown in Fig. 4 is subjected to a load P, both the matrix and the load will undergo elastic deformation by an amount e. The strain in the matrix (e m ) will be equal to the strain in the fibres (ef) :- i.e. " = e. and as E = e — o — , then θ = .£_£_ E m E f or ^ - If. "" E m where: tζ~ = stress E = elastic modulus If S m is the stress at failure of the matrix (i.e. its strength) and Sf is the stress at failure of the fibre (i.e. its strength) is desirable to match the ratios of stress at failure so that:- E f ~ E m However, it is not critical to achieve an exact match and an approximation will suffice. For example, if the fibres are say, 20 to 40 times stronger than the matrix, then a minor mismatch in the strength will not be significant. The load P required to strain the composite shown in Fig. 4 and 5 is related to the stress of the composite (tf"^ ) and the cross-sectional area of the composite ^ :- P = (€ . ( j ^ ) The total load P comprises the load arried by the fibres P f and the load carried by the matrix P m :- p - p f + p m and P m = (€ n ).(A m ) then( <T k ) (A k ) = ( 6" f ) (A f ) + ( 6~ m ) (A m ) or, as (5"= eE (eE k ).(A k ) = (eE f ).(A f ) + (eE m ). (A m ) i.e. E k = (E £ ).(A f ) + (E m ). (A m ) A k A k It is convenient to express the ratio of the cross- sectional area of the fibres and of the matrix to that of the composite in terms of the volume fraction of the fibres and matrix respectively:- A f = V f A k and A m - V m thus. Ei- — EJ V f + E mm V ":m and Ek,. == E f V f + E m (1 - V f } where: E k is tensile modulus of the composite E f is tensile modulus of the fibres E m is tensile modulus of the matrix •Thus the tensile modulus of the post can be calculated once the volume fraction of the fibres has been determined, or alternatively, once the tensile modulus has been set, the volume fraction of the fibres required to achieve the modulus can be readily calculated. The roadside marker post may be driven into the ground by the use of a jig as shown in Fig. 6, which also serves to help keep the marker straight. The jig acts in the manner of a pile-driver, and the distance moved by the marker will depend on the resistance offered by the ground and the velocity of the jig at the moment of impact, as well as the mass of the jig itself. The average force applied by the jig is:- F = M V t where: F = Average force M = Mass of jig V = Velocity of the jig at time of impact t = Duration of impact Any tendency of the marker post to buckle during the driving process is minimised by the presence of the jig, which ensures that the stress applied to the marker is uniform over its upper end. The jig 30 has grips or handles 31 which receive the edges of the post 10 and a striking plate 32 which constitutes the major portion of the mass of the jig. As will be apparent from the above description, roadway marker posts according to the invention do not lend themselves to be driven into hard ground by the application of a force to their free end as is the case with the posts described in the Australian patent specification 526,508. In normal circumstances, a hole will be dug in the ground and the marker placed therein. The barbs formed at or near the bottom of the marker post resist removal of the post from the ground. Where the marker is to be driven in the ground the driving jig shown in Fig. 6 is placed over a substantial portion of the marker to prevent flexing and to protect the top of the marker. Various modifications may be made in details of composition and process without departing from the scope and ambit of the invention. For example, a coat of polyurethane may be applied to the post by exposing a freshly applied paint film for a short period in a vaporised catalyst atmosphere. Such a process can utilise urethane linked alkyds, acrylics, epoxies, phenolics and polyester resins. Appropriate selection of the polymer coating to give a desired repeating molecular unit in the cured film can give rise to a wide variety of properties of the film.

Claims: CLAIMS : 1. A roadway marker post comprising an elongated web structure of fibreglass reinforced resin material characterised in that the resin is a catalytic setting resin and the fibres are substantially unidirectional. 2. A post according to claim 1 wherein the resin consists of a base material of saturated and unsaturated dibasic acids and a dihydric glycol dissolved in a solvent. 3. A post according to claim 2 wherein the solvent is styrene. 4. A post according to claim 2 or claim 3 wherein the resin includes a promoter selected from the group comprising di¬ methyl aniline, di-ethyl aniline, cobalt naphthenate, cobalt octoate and a 10% solution of di-methyl aniline in styrene. 5. A post according to any one of claims 2 to 4 wherein the resin includes a dilutent selected from the group comprising ethyl acetate, di-methyl phthalate, di-allyl phthalate, methanol, isooctyl acetate, styrene and water. 6. A post according to claim 1 wherein the resin is selected from the group comprising: a) neopentylglycol isophthalic polyester resin, b) isophthalic polyester resin, c) neopentylglycol orthophthalic resin, and d) orthophthalic polyester resin together with 0.25 to 76% flexible resin. 7. A post according to any one of the preceding claims and further including a filler in the amount of from 10 to 150% of the resin weight. 8. A post according to claim 7 wherein the filler is selected from the group selected from calcium carbonate, alumina trihydrate, asbestos flock, zircon flour, calindria 244 and antimony trioxide. 9. A post according to any one of the preceding claims wherein the resin is present in an amount of from 40 to 255% of the weight of the fibreglass. 10. A post according to any one of the preceding claims wherein the resin includes a catalyst selected from the group comprising benzol peroxide, methylethylketone peroxide and LCR. 11. A post according to any one of the preceding claims wherein the films are unidirectional save for a very small amount of cross woven films used to maintain the greater majority of the fibres in their unidirectional configuration. 12. A post according to any one of the preceding claims and further including a plurality of external coats of on- fibreglass material. 13. A post according to claim 12 wherein the external coat is formed from isophthalic neopentylglycol. 14. A post according to any one of the preceding claims and including a recess formed in the upper end of the post. 15. A post according to any one of the preceding claims and including an embossment at the upper end of the post. 16. A post according to any one of the preceding claims and including a plurality of barbs at the lower end of the post. 17. A post according to any one of the preceding claims wherein the volume fraction of the fibres in the post satisfy or substantially satisfy the following relationship:- E k = E f V f + E m (1-V f ) where: E k is the tensile modulus of the post E f is the tensile modulus of the fibres E m is the tensile modulus of the matrix ~ Tψ is the volume fraction of the fibres 18. A method for manufacturing a roadway marker- post- - comprising the steps of: (i) forming a mould having the shape of the finished roadway marker post, (ii) applying a gelcoat to the mould, (iii)adding substantially unidirectional fibreglass and a catalytic setting resin to the mould, and, (iv) pressing the components within the mould and retaining them in the compressed form until the resin has catalytically set. 19. A method according to claim 17 or claim 18 wherein the fibreglass is substantially unidirectional save for a very small amount of cross woven fibres used to maintain the greater majority of the fibres in their unidirectional configuration whilst the resin is being added to the mould. 20. A method according to claim 18 wherein a projection is formed in the mould so as to form a recess on the post. 21. A method according to claim 18 wherein a recess(s) is for ed in the mould so as to provide a projections) on the post. 22. A method according to claim 21 wherein the projections are in the form of barbs at one end of the post. 23. A method according to claim 18 wherein the fibreglass is laid in the mould in the direction of the longitudinal axis of the mould.

Inventors: NG ERIC, NG, ERIC
Applicants: BUILT RITE PRODUCTIONS PTY LIM, BUILT-RITE PRODUCTIONS PTY. LIMITED
Application year: 1986
Main classification: E01F9
IPC codes: E01F9