US2303462A - Road marker - Google Patents

Description

Dec. 1, 1942. A. A. HORNE 1 2,303,462

- ROAD MARKER I Filed Oct. 4, 1940 4 Sheets-Sheet 1 'IIIIIEZIIIIIIIIEQ ROAD MARKER Filed Oct 4, 1940 4 Sheets-Sheet 2 Dec. 1, 1942. A. A. HORNE 2,393,452 I ROAD MARKER Filed Oct. 4, 1940 4 Sheets-Sheet 3 mum I "Mum" A HIIIIIIITIJITTTTF I l I I M? his: 111;: 1

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ROAD MARKER Filed OO b. 4, 1940 4 Sheets-Sheet 4 a? as ea 76 W I s s s l w a W mw Q M77 Patented Dec. 1, 1942 UNITED STTES EPT 'l QFFICE ROAD MARKER Arthur A. Home, Wareham, Mass, assignor to The Calcibrite Corporation, Pawtucket, R. I., a corporation of Massachusetts Application October 4, 1940-, Serial No. 359,636

3 Claims.

My invention relates to road markers of the type adapted to be incorporated in suitable holes provided therefor in a road.

An object of my invention is to provide a road marker of plasticized material of a novel shape and provided with suitable means projecting therefrom to insure that the road marker will be a set cementitious road marker having substantially the same coefficient of expansion as the road into which=it is desired to be inserted se-' cured to said road by a cement also having the same coefficient of expansion as said road marker to provide a homogeneous mass when said cement is set comprising the adjacent portion of the road, the road marker and the cement, all portions of which have substantially the same coefficient of expansion so as to expand and contract as a unit with changes in temperature.

A further object of my invention is to provide a set cementitious road marker which when set may be more readily observed than present types of road markers as I preferably provide it with a convex upper wall observable over a greater area than the fiat upper walls of road markers formerly employed.

To provide means to form pockets for the insertion of cement in the road hole around the marker to positively bind the marker to the road, I preferably provide the side wall of the marker with peripheral flange means projecting circumferentially outwardly therefrom providing cement receiving pockets above said flange means so that cement laid therein may rigidly bind the marker against the surface of the road and against any tendency to have any portions thereof lift up on passage of any vehicular travel thereover.

To receive a greater portion of binding cement between the lower wall thereof and the bottom of the hole provided therefor in the road, I preferably provide the road marker with a concave lower wall and I provide said lower wall with locking ribs extending under said concave lower wall, at angles to each other projecting integrally downwardly from said body providing between them cement receiving pockets on the said concave lower wall to receive cement therein to positively prevent the marker from turning or 5 twisting as heavy vehicular trafiic passes thereover.

A further object of one embodiment of my invention is to provide a metal protective 'rimfor the marker constructed of noncorrosive, preferably resilient material to prevent the marker from chipping adjacent the edges thereof, and to provide a polished metal edge simulative of a frame to supplementally attract the eye of both the pedestrian and the vehicle operator.

The metal rim may also be provided with flange means projecting circumferentially therefrom for the purpose hitherto mentioned of generally locking the marker to the road, providing cooperating groove means on the inner wall thereof, which groove means may be readily filled by the plastic material of the marker during my novel method of manufacture forming cooperating flange means in the body of the marker contained within said groove means.

A further feature of my invention relates to improvements in manufacturing a road marker having a metal rim wherein circumferential flanges are formed in the rim by the expansion of the cementitious material during its forming and setting operating so that ribs will also be formed in the cementitious material projecting into the cooperating grooves simultaneously formed on the interior of the rim opposite the thus formed outwardly projecting flanges to provide strength to said flanges and a greater area for adhesion of the marker to the rim. I may also, if desired, provide irregular projections or planchets projecting inwardly from said rim with the cementitious material extending around said projections and into the holes formed by the nicking-in of said projections or planchets.

A further feature of my invention is that '1 preferably employ a road marker of a novel type resistant to moisture or other water and spilled gasoline or oil, or road oil, normally present on the road surface. I have discovered that such a road marker may be constructed of the hydraulic gypsum cement material described and claimed in Patent #1090525, Hydraulic gypsum cement material and manufacturing the same. issued August 24, 1937, to Robert S. Edwards, but that an improved road marker is provided if a suitable oxide pigment, a suitable resin adhesive, and a suitable plasticizer be employed in association with said hydraulic gypsum cement material, it being my opinion that a reaction takes place between said hydraulic cement material and the pigment oxide to provide a stronger and more desirable road marker.

In addition, the incorporation of the resin adhesive and the plasticizer therein not only provide sufiicient moisture for the setting of the road marker, but also render said road marker when set, water resistant and gasoline and oil resistant.

A further object of my invention is to provide a road marker which is a pure white in color, a result not possible in standard cements. The plastioizer also is preferably so regulated as to make the marker suitable for use with low winter temperatures and high summer temperatures.

A further object of my invention is to provide a quick setting cement for binding the markers to the road, constructed of substantially the same materials, but with a slightly greater percentage of plasticizer. I have also found that in use under the conditions of heat necessary for cutting a suitable hole in the road for the marker and the heat of the cement when applied, that a certain amount of gum or adhesive from both the cement and marker will melt to provide a tighter bond for the marker to the road.

A further object of my invention is to provide a road marker having better wearing qualities than former types of road markers constructed of rubber, cement, or other material.

These and such other objects of my invention as may hereinafter appear will be best understood from a description of the accompanying drawings, which illustrate various embodiments of road markers constructed in accordance with my invention, the method of manufacturing one of said embodiments and the steps in the method of incorporating my improved road marker within a suitable hole in the road.

In the drawings, Fig. l is a plan view of one embodiment of road marker constructed in accordance with my invention employing a metal retaining rim.

Fig. 2 is a cross sectional view therethrough taken along the line 2-2 of Fig. 1.

Fig. 3 is a reverse plan view of the marker shown in Fig. 1.

Fig. 4 is a plan view of the preferred embodiment of my invention.

Fig. 5 is a cross sectional view taken along the line 5-5 of Fig. 4.

Fig. 6 is a reverse plan view of the embodiment of my invention shown in Fig. 4.

Figs. 7-10 illustrate steps in the method of manufacturing the embodiment of my invention shown in Figs. 1-3, Fig. 7 being a diagrammatic side elevation illustrating the step of cutting metal strips of the desired length of the metal binding rim and the supplemental step of forming planchets projecting integrally from one side thereof, Fig. 8 being a diagrammatic vertical sectional view of a suitable mold for plasticizing or setting said embodiment with the metal rim formed in circular formationwith the planchets projecting radially inwardly thereof and with said rim opposite, a series of vertically spaced grooves formed in the die, Fig. 9 being a vertical,

sectional view similar to Fig. 8 after a suitable mixture of the component materials of said marker has been inserted in heated, semi-plastic form within the die, and Fig. 10 being a vertical sectional view similar to Figs. 9 and 10 after. the ram has been so lowered in the die to form the marker and so cooled to set the marker in the desired finished formation.

Fig. 11 is a diagrammatic vertical sectional view taken through a portion of a road and a suitable hole formed therein for the reception of the marker and having a layer of cement on the bottom thereof and through a marker of the type shown in Figs. 1-3 in a position above the hole prior to actual insertion within the hole, the section line through the marker being slightly offset from the diameter to more clearly illustrate the invention.

Fig. 12 is a diagrammatic vertical sectional view similar to Fig. 11 after the marker has been inserted within its respective hole.

Fig. 13 is a diagrammatic vertical sectional view similar to Fig. 12 after a supplemental amount of a binding material has been inserted in the spaces between the edges of the hole and the marker.

Fig. 14 is a diagrammatic vertical sectional w'ew similar to Fig. 13, but employing the type of marker illustrated in Figs. 4-6.

In the drawings, wherein like characters of reference generally indicate like parts throughout, H3 and Hi generally indicate embodiments of road markers constructed in accordance with my invention. Insofar as the novel structural features of road markers are concerned, they are novel of whatever type of plasticized material may be employed, although, as will be described later, I preferably employ a set cementitious material having substantially the same coefficient of expansion as the road into which the road marker I is desired to be inserted. In order that the road marker may be more readily observed when in position on the road, than former types of read markers, my improved road markers are preferably provided with convex upper walls 12 or l2. While the road marker itself may be of any desired shape, most types are of general cylindrical shape, such as a true cylinder orsolid polygon.

So far as I am aware, I am the first to provide means, preferably flange means !4 or M projecting outwardly from the side wall IE or 16' thereof circumferentially of said marker to provide cement receiving pockets above said flange means to positively lock the marker to th road when in set position on the road. Said flang means may comprise the vertically spaced circumferential ribs 14, as in the embodiment of my invention shown in Figs. 1-4, providing above and between said ribs I4 the cement receiving pockets 19, or the flange 14', in the embodiment of my invention shown in Figs. 4-6 projecting circumferentially from the lower portion of the sid wall i6 providing above the step it? formed between said lower flange portion and the upper portion of the marker side wall a cement receiving pocket l9.

While my improved marker may be constructed with a fiat lower wall, as is often desirable in small sizes, I also believe I am the first to provide a marker having a concave lower wall 20 or 20 for receiving a greater area of cement in the pocket formed thereby to assist in binding the lower surface of the marker to the bottom of the road hole and I also believe I am the first to provide means 22 or 22' projecting downwardly from such a concave lower wall 20 or 20' to provide integral locking ribs projecting downwardly within said concavity, bonding it to the cement to prevent relative rotation or turning of the marker on passage of heavy vehicular traffic thereover, in my preferred embodiment, said means comprising the marker ribs 22 extending under said lower wall at angles to each other and projecting integrally downwardly from said body providing cement receiving pockets 23 between them. In the preferred embodiment I preferably employ the two locking ribs 22a or 2211. and 22b or 22b extending diametrically across said concave lower wall 20 or 20 at right angles to each other and. projecting integrally downwardly from said body to substantially the level of the outer edge of said concave lower wall 20 or 20', said edge being also the lower edge of the respective side wall It or it.

The embodiment of my invention shown in Figs. 1-3 includes the metal retaining rim 24 to provide a bright metal edge polished by trafiic to be more readily observable to the pedestrians and vehicle operators and to prevent chipping of the material of the marker. As stated, the flange means projecting outwardly from the side wall of the marker circumferentially thereof comprises in this embodiment, a plurality of vertically spaced circumferential ribs M projecting outwardly from the side wall is of said rim, said ribs l4 being preferably integrally pressed outwardly from the side wall of said rim and a forming on the inner surface cooperatingly formed vertically spaced circumferential grooves 26 adapted to receive the male flanges 28 projecting integrally outwardly from the cement body of the marker, the side wall it of said rim being plasticized to the side wall 32 of said marker body with the outer walls of the flanges 23 projecting integrally outwardly from the body of the marker being plasticized within said cooperating grooves 26.

It is thus obvious that cement receiving pockets 19 will not only be provided above the upper circumferential flange, but also that, supplemental cement receiving pockets !9 will be also formed between each respective vertically spaced circumferential flange for positively holding the marker flat on the road. In the embodiment of my invention shown in Figs. 1-3, I preferably provide supplemental means to assist in rigidly securing the metal rim 24 to the body of the marker and for this purpose I provide the nickedin planchets 34 projecting radially inwardly at spaced distances through the area of said rim into the body of said marker with plasticized material in the body of the marker surrounding said planchets and with plasticized material from said body filling the planchet holes 35.

My invention also relates to improvements in the method of making a road marker having such a metal rim 24 as more clearly illustrated in Figs. 7-10. Said method comprises forming a metal strip 24 of a length substantially equal to the desired circumference of the road marker and where it is desired to employ the planchets 34 in the rim, nicking-in a plurality of planchets 34 to project from one side thereof and also therefore providing the planchet holes 36 from the spaces from which the integral planchets 34 are nicked-in. While this may be done in any suitable manner, I have diagrammatically illustrated in Fig. 7 a suitable means for this purpose, which comprises a plurality of rolls for nicking-in the planchets, comprising an upper hob roll 38 having the projections 4i] projecting therefrom at spaced intervals adapted to fit into suitable cooperating female depressions 42 formed in the die roll 44 rotating underneath it. A continuous piece of strip material 46 is passed between said rolls and the roll projections ll! project downwardly through the strip of material 46 into the depressions 42 of the cooperating roll to nick in the integral planchets 534 while simultaneously providing the planchets holes 35. Then, after the planchets 34 are suitably formed in the strip 46, the strip is cut by means of a suitable knife 48 into the desired lengths 24 for the metal rims. If the planchets be not employed, however,'it is obvious that the rolls 38 and 8 may be omitted. I then arrange said outoff strip 24 in circular formation to provide a hollow cylinder 58 with the planchets 36 projecting radially inwardly thereof, preferably as shown in Fig. 8 within a suitable die 52 having a plurality of vertically spaced circumferential grooves in the lower end thereof opposite the outer surface of the inserted metal rim 24. The lower surface of the die hole may be provided with the convex projections 56 projecting upwardly therefrom of quadrant shape, providing the grooves 58 between them to shape the locking ribs 22a and 22b on the lower concave wall 28 of the marker extending diametrically across the lower wall of the marker at right angles to each other and projecting integrally downwardly from the body of the marker to substantially the level of the outer edge of the lower concave wall thereof. The quadrant-shaped projections 56 are preferably of concave formation to provide the concave lower wall 20 of the marker. The cementitious material 60 after it has been heated to render it semi-plastic is then put into the hollow cylinder 53 as shown at 56 in Fig. 9. The plunger 62 is then inserted within the die hole 52 under a suitable plasticizing pressure to con fine the cementitious material 5E! within said hollow cylinder 58 to set and plasticize it as a marker l0 within said hollow cylinder 56 and to the inner surface of the wall thereof, the pressure exerted on the plunger 82 being sufiicient to force the cementitious material radially outwardly against the inner surface of the rim to force vertically spaced portions of said metal rim 2t radially outwardly into said die grooves 5 to provide the plurality of verticallyspaced circumferential ribs M projecting circumferentially outwardly from the outer surface of the side wall of said rim simultaneously forming the grooves 26 on the inner surface thereof as the material is bent outwardly from the inner surface of said Wall and thus also simultaneously forcing said cementitious material 5i! into said thus formed grooves 26 to provide a similar plurality of vertically spaced circumferential ribs 28 projecting outwardly from the set marker body plasticized to and. within said grooves 26, the cementitious material also being plasticized to the inner surface of the side wall of said metal rim 24. Where planchets 34 are employed, the cementitious material B0 is also forced around said planchets 34 and into said planchet holes 36 to provide a marker having set cementitious material around said planchets 34 and within said planchet holes 36 binding said marker it to said rim 24. I have shown the annular channel 64 around the die 52 provided with an inlet 66 and an outlet tit. With most plasticizable'materials a cooling action is required to cause them to become plasticized or set and for this reason cool water may be circulated around said annular chamber 64. For

' other plasticizable materials, however, steam may be employed if desired to assist the plasticization,

vulcanization, or other desired setting treatments thereof. It is apparent that the embodiment of my invention shown in Figs. 4-6 without a rim may be suitably molded and set in a similar press with the respective grooves 55 omitted.

In addition, as stated hitherto, I believe I am the first to provide a new combination, comprising the road surface 79 having a marker it therein contained within a'suitable pro-formed hole 12 therefor in said road'surface and secured'to the edge 14 and base 16 of said hole by a suitable cementitious material 18, with said marker [0, said road surface 10 and said cementitious material 18 all having substantially the same coefficient of expansion, so that the entire mass of the road surface adjacent each marker will expand and contract as a unit with changes in temperature.

While any suitable cement and any suitable set plasticized marker may be employed for this purpose as long as they have substantially the same coemcient of expansion as the road and as each other, I preferably construct my marker and the cement of the materials to be explained in more detail, which have substantially the same coeflicent of expansion as concrete, road tar or asphalt.

Figs. 11-13 illustrate the actual steps of laying a road marker l constructed in accordance with my invention in such a hole 12 in a road surface Ill. The road surface is first provided with the holes 12 for receiving the road markers ID of slightly greater size than said road markers. Each hole 12 may be made in the road surface in any manner well known in the art, either by a pneumatic drill or by first heating the road surface and cutting out a cylindrical portion forming the hole 12. A layer 89 of cement I8 is first laid in the base 16 of the hole '12. marker I0, preferably one having the flange means I4 on the side wall thereof, a concave lower wall 20 with the locking ribs 22 hitherto described is then lowered within said hole 12 as shown in Fig. 12. Then a supplemental amount of cement 82 is poured into the annular space 84 between the side wall 14 of the hole and the side wall I6 of the marker and the cement allowed to set in the road. Where an adhesive substance is employed in the marker and in the cement and if the cement is applied hot, the adhesive becomes somewhat molten before setting, tending to form the marker, cement and road surface adjacent the marker into a somewhat homogeneous mass. Any suitable type of adhesive may be employed and I employ the word cement in its broadest sense, comprising any suitable material for permanently sticking themarker [0 within its respective hole 12, whether it comprises a true cement, a mastic, or other type of adhesive. It is obvious that the cement 18 will fill in the quadrant or other shaped pockets 23 between the ribs Ho Or 221) and will also exude upwardly in said annular space 84. The cement which exudes in said pockets 23 forms the quadrant shaped projections 88 projecting upwardly therein also of cooperating convex shape complementary to the concave shape of the lower wall 29 of the marker which are plasticized not only to the side Walls ofthe ribs 22a and 22?), but also to the concave lower surface 20 of the marker and have convex upper surfaces 90 complementary in general to the concave upper surface of said mold projections 56 hitherto described and it is apparent that these projections 88 will positively abut the ribs 22a and 22b and thereby prevent any turning movement of the marker on passage of heavy vehicular traffic thereover. While a supplemental amount of cement may be poured in the annular space 84 after the marker is laid, if desired, it is obvious that when said annular space is filled as shown in Fig. 13 at 82, that cement projections 92 are also formed above each respective flange means I4, and are also plasticized to the upper surfaces of each respective The flange means and the sidewall l6 of the marker to provide rigid set means above each respective flange M to positively hold the marker flat on the road against any'tendency of heavy vehicular trafiic to raise the marker from the road as is often caused by the suction of pneumatic tires passing thereover, or when a brake is suddenly applied to a fast moving vehicle. I have shown in Figs. 11-13 the marker shown in Figs. l-3 set in the road, and I have shown in Fig. 14 the embodiment of marker shown in Figs. 4-6 thus set in the road with a singl annular projection 92' overlying the step 18' to hold the marker flat on the road. As also shown in Figs. 11-14, as the upper surface of the markers is convex as at l2, it will provide a crown to make the road marker visible over a greater area and not impede the passage of vehicle traflic thereover. It is also apparent that such a shape prevents snow plows, or other road scraping devices from abutting against a straight edge of a marker'to tend to lift it from the road, the convex surfaces merely slightly lifting the snow plow, or other scraper as it passes thereover.

In the prior art, great difliculty has been experienced with both metal and rubber road markers as they do not expand evenly with the road on changes in temperature and thus tend to work out in time. With such an uneven expansion, water is apt to seep in between the road hole and marker, which, when the road is frozen tends to cause the usual frost cracks in the road surface. While it has been suggested to make road markers out of cement, in most instances it is desirable to have white road markers and it has been found impossible to make a pure white out of Portland or other common cements now on the market. Great difliculty has been also experienced in providing a road marker which is resistant not only to the elements, but to other materials normally on traveled roads, such as water or moisture, spilled gasoline or oil from vehicles, or road oil, where employed, and I have endeavored to provide a road marker constructed of a suitable set cementitious material which is water resistant and gasoline and oil resistant and at the same time has the desired adhesive and wearing qualities and substantially the same coefficient of expansion as concrete, road tar or asphalt of which roads are usually constructed to expand and contract evenly therewith on changes in temperature to overcome the objections of the road markers in the prior art as described above. I have found for this purpose that hydraulic gypsum cement material described in Patent No. 2,090,625 for Hydraulic gypsum cement material and manufacturing the same, issued August, 24, 1937, to Robert S. Edwards of Milton, Massachusetts, is such a desirable material. As said material has not as yet acquired a trade name known in the art, although it is now sold under the name Calcibrite, for shortness of description in the specification and claims I will refer to this material as Edwards phospho-gypsum cement and where such a phrase is employed henceforth in the specification and claims it will refer to the hydraulic cement covered and claimed in said Edwards patent. Cement made from natural rock, gypsum and cement made from anhydrite, as described in said patent may be alternatively employed. Such a material when used alone is not as oil resistant, gasoline resistant, or water resistant as desirable. I have also discovered that such a material may readily have an oxide pigment incorporated therein to impart the desired color thereto, and I believe that a certain reaction takes place between such an oxide pigment and the cement itself during setting, as to improve the wearing and other qualities of the marker or cement if such materials be employed as the base for the marker or cement. A certain amount of water is also required to initiate the starting of the setting of the cement, suflicient water to complete the setting being furnished by the atmosphere. To prevent any excess of water from adversely afiecting the cement or marker and hence the moisture resistant characteristics of the set cement or marker and to improve the resistance of the set marker and cement against gasoline, steam, or other waste materials which are often spilled on the road surface and to act as an adhesive bond, I preferably, in association, with the pigment employ a suitable resin adhesive and also preferably employ in association therewith a suitable plasticizer. Whether the adhesive and/or plasticizer react with the Edwards phospho-gypsum cement, or the pigment oxide is not known, but I have found by experience that a marker constructed of these materials when set, or a cement so constructed for binding the marker to the road, when set has the desirable characteristics of a suitable marker or cement for all of these purposes. The resin adhesive is preferably ground fine. The Edwards phospho-gypsum cement is graded from down to .325 mesh. The pigment oxide is in powder form. The resin adhesive, the Edwards phospho-gypsum cement and the pigment oxide are first measured or weighed. They are then put in asteam jacketed mixer in suitable proportions, and after the plasticizer is then added, heated up to 200-300 F. While they are being mixed by this heat treatment the pulverant materials are rendered semiplastic to provide the semi-plastic mass 60 to be inserted in the die 52 in the manner hitherto explained. If desired, steam under pressure may be inserted in the annular jacket 64 to initially maintain these materials at this high temperature and the die 62 is then forced into the mold under a pressure of from 60 to 125 tons. I have found that the materials will become set in about thirty seconds and if desired cool water may be passed through the annular chamber 64 during this setting operation. The resin adhesive contains a certain amount of free water even in dry pulverant form and a certain amount of water is contained in the plasticizer and I have found that the water derived from the resin adhesive and plasticizer is sufficient to initiate sufficient setting of the marker within the die 52 in said period of thirty seconds, so that when the complete marker I shown in Fig. 10 is removed from said mold, it will be in solid, at least partially set form. If desired, the marker after fifteen seconds may be thrown into a bath of cold water to complete the setting and/or cooling.

As explained hitherto, the exact reaction which takes place between the different materials and the water is not understood, but with such a treatment the road marker is suitably set for practical purposes as I have found from the manufacture of many road markers. I have found in practice that best results can be obtained in the manufacture of such road markers by employing a mixture prior to setting of 50-75% Edwards phospho-gypsum cement, 12-23% resin adhesive, 15-30% pigment oxide and 2-8% of plasticizer. Any suitable resin adhesive, synthetic or natural, of a type to stand summer and winter temperatures when mixed with a suitable plasticizer may be employed. I preferably, however, employ a suitable type of natural resin, which may or may not be fossilized, in fact, any suitable type of natural resin described in a book entitled Natural Resins andsold by the American Cyanamid Company, or otherwise. I have actually employed Congo gum, pontianak gum,

Manila gum and kauri, and I have also attained good results with a synthetic resin sold under the trade name of Rezyl.

Any suitable type of oxide pigment may be employed, depending on the desired color of the marker. I have employed titanium dioxide T10: which I disccvered produces the best white and reacts in a desirable manner with the Edwards piiosphcgypsum cement to provide a stronger marker; also zirconium oxide ZrOz for a white marker; ferric oxide FezQe for a red or brown marker; cadmium sulfide CdS for an orange marker; chrome yellows for a yellow marker and other pigment oxides for various other desired colors.

I employ the words oxide pigment to include any suitable type of metallic pigment derived from its oxide. In many instances the actual oxides are employed in the trade as pigments for certain colors. For other colors the oxide may be suitably modified to provide the best type of pigment, as for instance commercial chrome yellows for yellow, or cadmium sulfide for orange.

As a suitable plasticizer, oastor oil, tung oil, beeswax, or other suitable natural plasticizer may be employed, or any synthetic plasticizers such as tri-cresyl phosphate may also be employed.

Typical formulas which I have employed for making various types of markers are as follows:

Per cent Edwards phospho-gypsum cement 50 Congo gum 20 Titanium dioxide 30 Castor oil 3 This will produce a white marker.

Edwards phospho-gypsum cement 66 Pontianak gum 16 Titanium dioxide .04 Chrome yellow 14 Tung oil 4 This will produce a yellow marker.

Edwards phospho-gypsum cement '75 Manila gum 12 Cadmium sulfide (orange) l2 Castor oil 4 This will produce an orange marker.

Edwards phospho-gypsum cement 60 Titanium dioxide 20 Congo gum 20 Castor oil 3 This will also produce a white marker.

As also stated, substantially the same mixtures may be employed as a cement for setting my improved road marker into the suitable hole therefor formedin the road surface, but as a slightly more plastic cement is desirable, I preferably employ the same materials as employed for making the marker in substantially the same proportions but increase the amount of plasticizer employed to 8-14%.

In the actual laying of the road I have attained best results with my improved marker and cement constructed of Edwards phospho-gypsum cement and the other materials hitherto described, by cutting a hole 12 in the road after suitably heating the adjacent road surface and pouring the cement at a temperature of between BSD-400 F. This will tend to melt the adhesive both in the road marker and in the cement and effect a better bond between the road marker and the cement. A discussion of whether the adhesive fills the voids in the marker and adjacent road surfaces, or whether due to its temperature is melts to provide a tighter bond, is believed immaterial, as results have given much better bonding characteristics by employing the adhesive hitherto described in proper proportions in both the marker and the cement. The amount of plasticizer employed in both the marker and the cement is regulated by the lowest temperature in winter and the highest temperature in summer to provide a marker which will still remain plastic and not crack under the cold conditions of winter and not become too plastic to melt and pick up dust particles under the heat conditions of summer.

I preferably employ Edwards phospho-gypsum cement as I have found that when mixed with the other ingredients it becomes the least water soluble and most suitably set of any cement now on the market and thus has a tendency to outlast other types of cement.

also explained, I am enabled by the use of this material and a suitable whitening pigment to obtain a marker more nearly pure white than any hitherto provided to thus be more readily discernible to traffic in use, the rubber tires acting as an eraser and cleaning the marker.

Tests have also proven that the marker itself is somewhat stronger than markers constructed of other types of cement and when mixed with the materials hitherto described will have moisture resistance, oil resistance and gasoline resistance not present in other types of markers.

I have also found that the reaction produced by these materials provides such a strong structure that there is much less tendency of the marker itself to chip than in markers constructed of other cements. If desired, however, to render the marker less shatterable, a certain amount of asbestos or other fiber may be incorporated in the mix.

It is understood that my invention is not limited to the specific embodiments shown or methods describedfand that various deviations may be made therefrom without departing from the spirit and scope of the appended claims.

What-I claim is: I r

a 1. A road marker adapted to be inserted in a recess in a highway and retained therein by cementitious material comprising a set cementitious body having substantially the same coeflicient of expansion as the road into which it is desired to be inserted, having an upper wall, a side wall having flange means projecting outwardly therefrom circumferentially thereof at a distance belowthe top thereof, thecross vseutional area of said marker being substantially P uniform above said flange means to provide cement receiving pocket means above said flange means, and a lower wall having locking ribs of substantial width extending across said lower wall at angles to each other and projecting integrally downwardly from said body providing cement receiving pockets between them.

2. A road marker adapted to be inserted in a recess in a highway and retained therein by cementitious materialcomprising a set cementitious body having substantially the same coefficient of expansion as the road into which it is desired tobe inserted, having an upper wall, a side wall having flange means comprising a stepped lower portion of greater circumference than the upper portion above said step, projecting outwardly therefrom circumferentially thereof providing cement receiving pocket means above said flange means and a concave lower wall having two locking ribs of substantial width extending diametrically under said concave lower wall at right angles to each other and projecting integrally downwardly from said body to substantially the level of the outer edge of said con- 'cave lower Wall providing cement receiving pockets between them.

3. A road marker adapted to be inserted in a recess in a highway and retained therein by cementitious material comprising a set cementitious body having substantially the same coefflcient of expansion as the road into which it is desired to be inserted, having an upper wall, a side wall having flange means projecting outwardly therefrom circumferentially thereof, comprising a stepped lower portion of greater circumference than the upper portion above said step, providing cement receiving pocket means above said flange means and a concave lower wall having locking ribs of substantial width extending under said lower Wall at angles to each other and projecting integrally downwardly from said body providing cement receiving pockets between them.

ARTHUR A. HORNE.

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