US3008389A - Ballasted earth compaction equipment - Google Patents

Description

Nov. 14, 1961 w. L. HICKS BALLASTED EARTH COMPACTION EQUIPMENT Filed April 27, 1959 INVENTOR. William L. Hicks ATTORNEYS United States Patent 3,008,389 BALLASTED EARTH coMPAcTIoN EQUIPMENT William L. Hicks, 820 8th St, Boulder, Colo. Filed Apr. 27, 1959, Ser. No. 809,055 4 Claims. or. 94--50) This invention relates to acomposition of matter for use as a dry ballast for earth compacting equipment, and more particularly to a composition of matter of at least two distinct particle size ingredients arranged for easy separation for varying the apparent density of a dry ballast for earth compacting equipment.'

In my co-pending applications Serial No. 537,259, filed September 28, 1955, entitled Vehicle Tire Ballast, now Patent No. 2,884,039, dated April 28, 1959, and Serial No. 797,476, filed March 5, 1959, entitled Pneumatic Tire Ballast, there are described and claimed ballasted pneumatic vehicle tires which include a rubber pneumatic tire under usable air pressure and filled with a dry ballast. Such ballasted pneumatic vehicle tires are normally used on tractors and the like for providing weight and absorbing bumps and jolts of the rough terrain over which the tractor passes.

According to the present invention I have now found that a highly etfective and eflicient ballast consisting of a mixture of coarse, granular material and finely divided powder may be used in a rigid shell, compacting roller to provide the essential weight necessary for the amount of compaction required and produce minimum resistance to rolling of the compacting equipment. The ballast according to the invention provides a variable weight, low cost ballast which permits a low cost method of weighting a rigid shell, compaction roller.

Prior to the present invention one ballast was a liquid composition, which is normally water or a water solution of calcium chloride or the like. This ballast was filled in a compaction roller but due to the construction of the roller, it would not be filled 100% full. Such liquid compositions are not commonly available for weights in excess of 10 to 12. pounds per gallon of ballast material. As a result of the relatively low density, the maximum weight which could be added to a drum or roller was often much less than that necessary for the compaction job required. Another prior art method of adding ballast to such compaction rollers is by the use of dry sand. The additional weight provided by the dry sand may be somewhat increased by adding liquid such as water or water and antifreeze to the sand. Still another method is to weld iron or steel weights inside the drum. All of the prior art methods, however, of adding ballast to the compaction roller evokes the problem of filling the drum solidly enough to prevent excessive movement of the contained material which causes friction losses in the rolling and increases the power necessary to pull such rollers. The physical construction of the compaction shells and the method of introducing ballast makes it virtually impossible to fill the shell completely full. With water the sloshing and movement of the water or with sand or sand and water there is considerable friction against turning and an appreciable drag is exerted on the turning of the roller thereby increasing the power necessity for pulling the roller. Furthermore, the total weight of water plus sand does not exceed about 14 pounds per gallon.

Since weight has been one of the major considerations in the design of compaction rollers, one other prior art method of obtaining weight for such rollers has been to increase the thickness of the metal skin or add iron or weights thereby increasing the dead-weight of the compaction roller. With a hollow roller it is possible to still further increase the weight by addition of ballast. It is, obvious, however, that increasing the thickness of arrests) Patented Nov. 14,1961

2 the skin to increase the weight of the roller greatly increases the cost of the roller and reduces the variability of the weight of the roller. 9

An important object of the present invention is, therefore, to provide a composition ballast for compaction equipment which provides a variable apparent density material and which by its action on movement of the roller completely fills the space in the roller with a fluid mass which does not essentially resist turning of the roller and reduces the necessary power for pulling the compaction equipment over the ground.

It is a further object of the invention to provide a ballast which is a mixture of a coarse material and a very finely powdered material of substantially 100 mesh or finer which permits an easy physical separation of the materialsand permits varying ingredients of composition and thereby vary the apparent density of such a ballast mixture.

Other objects and advantages may be readily ascertained by referring to the following specification and appended illustrations in which:

FIG. 1 is a cross-sectional, side elevational view of a sheeps foot roller illustrating an at rest condition of such roller partially filled with a composition according to the invention;

FIG. 2 is a cross-sectional elevation of -a sheeps foot roller in accordance to FIG. 1, showing the dynamic condition of the composition after several turns of the sheeps foot roller.

FIG. 3 is a cross-sectional view of an asphalt roller showing the condition-015a ballast composition of the invention in an at rest position; and,

FIG. 4 is a cross-sectional view of an asphalt roller showing the dynamic condition of the ballast material after several revolutions showing its fluidized characteristics complete filling of the roller.

A sheeps foot roller, as illustrated in FIGS. 1 and 2, consists essentially of a rigid, metal skin 1 in a hollow cylindrical shape closed at both ends (not shown) and having an axle 2 mounted in bearings (not shown) secured in the ends, as is common practice. The axle 2 is journalled in a yoke or other supporting mechanism, part of which is shown at 3. To complete the sheeps foot roller, a series of feet 4 extend around the peripheral extent of the drum and lengthwise thereof, three only being shown but it is understood that such feet extend completely around the drum. As shown in FIG. 1, ballast 5, which is-a composition according to the invention, fills from to of the volume of the roller leaving a space 6 for air. In filling the drum, the ballast, which consists of a substantial portion of finely divided powder, is easily airborne and the roller may be filled by blowing the airborne powder into the shell to an essentially filled condition. Due to air-borne condition (that is a slow settling rate of the composition) the roller cannot 'be packed solidly and after settlingthe ballast leaves an air space 6. The roller filling openingis completely closed and it is then ready for operation. Due to the physical characteristics of the composition and the roller, it is virtually impossible to pack the material so tightly in the drum that all air is excluded and the ballast is essentially a solid pack. In filling the roller, it is preferable that the volume of the ballast amounts to from 80-97% of the volume of the roller calculated on the settled density of the ballast. To determine the usable settled density of the ballast a laboratory determination has been developed in which a graduated cylinder with a tight fitting piston is filled with the powdered ballast composition. The cylinder and piston is tamped until further settling is not noticeable. At this point the material is quite hard and it may be considered the maximum settled density of thematerial for calculating the fill of the roller.

' The asphalt roller illustrated in FIGS. 3 and 4 comprises a metal skin which is in the shape of a hollow cylinder having ends, not shown, supporting bearings, not shown, for an axle 11. The axle 11 is mounted in a yoke 12 or other support which is rotatably mounted by means of a shaft 13 in a framework 14 so that the roller may be steerable by a mechanism, not illustrated but may be such as is commonly used in the industry. Such rollers are normally utilized with hot asphalt and a conduit 15 terminating in one or more nozzles 16 provide cooling water sprayed on the roller. The roller is filled in a manner similar to the roller of FIGS. 1 and 2,' and in settled condition the ballast 18 fills from 80-97% of the volume of the roller leaving an air space 19 thereabove. As illustrated in FIG. 4, the ballast essentially completely fills the drum with an air-borne ballast providing a balanced roller which is easily moved.

The ballast illustrated in FIGS. 2 and 4, as pointed out above, consists of a composition of part coarse material and part finely divided powder. In the illustration of FIG. 2, the coarse material 7 is interspersed and maintained air-borne by powder 3 so that the composition is completely air-borne on agitation or rolling of the roller and continued agitation maintains it essentially homogeneous. The ballast composition of FIG. 4 consists of coarse material 21 maintained in air-borne suspension by the powder during agitation or rolling essentially filling the roller and maintain it balanced.

Example I A sheeps foot roller as illustrated in FIG. 1 was filled with a mixture of about 70% by weight of an iron ore, known as monazite sand, crushed to about 20 mesh and the remainder or 30% by weight being barium sulphate pulverized to 300 mesh. The resulting mix in maximum settled condition was determined to have a density of about 3.4 which is equivalent to about 28 pounds per gallon. This mixture was filled into the roller, to a level calculated by weight to be about 93% of the total capacity of the roller. Immediately after filling the roller, however, the drum appeared to be 100% full because of the expanded and aerated condition of the mixture. When pulled at an estimated two miles per hour the roller pulled easier and with less power than a lighter roller partially filled with water or sand. Compaction produced by the roller filled with the ballast of the invention was observed to be much greater and the requisite compaction was obtained much faster than with the lighter rollers filled with sand or water. It was the opinion of the roller operator that the necessary degree of compaction was produced with fewer passes of the roller. After operation and settling of the material, the drum with its ballast appeared similar to that of FIG. 1.

Example II For laboratory evaluation of the results, a closed metal drum of about a three foot diameter and four inches in width was constructed; The drum was mounted with an axle through the center in the manner of a compaction roller and was mounted in such a way that the drum could be rotated. The axle was mounted in bearings mounted on the ends of the drum so that the drum would turn freely. This drum was then filled to 90% of its capacity, calculated on the settled density, with a dry mix consisting of 60% by weight of monazite sand of about 20 mesh and 40% of 300 mesh soapstone. The resulting mixture weighed 17 pounds per gallon at its maximum settled density. In the static condition, that is with the material settled, the drum was definitely unbalanced and on slight turning the unbalanced condition was easily observed by the drum oscillating due to the weight of the material settled toward the one part of the drum. Upon rotating the drum for about two revolutions, however, the ballast material in the drum had absorbed enough air to completely fill the drum and produce an essentially balanced condition. In this condition the drum rotated easily and smoothly with no jerking or loping due to movement of the material internally of the drum. I

The dry mixture was removed from the drum and the ballast was separated into its two components by screening. The 40% by weight of soapstone was replaced with an equivalent amount of 300 mesh barium sulphate. The resulting mixture had a weight at its settled density of 27 pounds per gallon. When this material was filled into the drum at about 93% of the capacity of the drum at the settled density of the ballast, the same conditions were observed with the lighter ballast mixture of monazite sand and soapstone. That is, in a static condition the drum was unbalanced, but in the dynamic rolling condition the drum appeared well balanced and rotated easily and smoothly.

Example III A ballast mixture of about 70% by weight of lead shot having a diameter of about one-eighth inch was mixed with 30% by weight of 300 mesh barite powder which was then filled into the drum of Example II. This mixture at its maximum settled density had a weight of 50 pounds per gallon. The mixture was filled to about 93% of the volume of the drum at the settled density of the mixture. The dynamic conditions of this mix in the drum were essentially the same as demonstrated with the lighter ballast mixtures. In the static or settled condition the drum was unbalanced, difiicult to turn and tended to oscillate due to the settled weight in the lower part of the drum. After several revolutions of the drum, however, the rolling characteristics changed to an apparent balanced drum which rotated evenly and smoothly with very little power required to rotate the drum.

As is well known in the road building, the amount of compaction necessary for a particular area is determined by the type of ground and the particular road surface being built over the ground. To produce the necessary compaction for supporting the roadway, various types of equipment are utilized, but the major part of any compaction is the ability to produce a certain necessary weight per unit of contact area of road. With my ballast it is obvious that a substantial variation of weight may be introduced into compaction equipment to produce the necessary weight and still provide an easily turned, balanced roller. By properly proportioning the ingredients or by changing the composition of the ingredients, the settled density of the ballast may be readily changed from 10 to 50 pounds per gallon. It is readily apparent that the density of the ballast may be easily changed to conform to the necessary conditions without a waste of material or without having to provide large storage facilities for different mixes of different compositions. Thus if granular monazite is being used, by changing the quantity of monazite sand in relation to the fine powder, the density of the composite material may be changed.

A distinct advantage with the ballast of the invention is found in its air-borne characteristics which make the job of. filling or unloading such rollers easy and quick. There is no simple or easy way to fill or empty sand from such a roller, but with applicants ballast it may be air-borne and blown into the roller or it may be airborne in the drum and removed by injecting air into the roller and removing the air-borne powder.

While the invention has been described with reference to particular examples, there is no intent to limit the same to the precise details so set forth, except as defined in the claims.

I claim:

1. Ballasted earth contacting equipment comprising an essentially air-tight, rigid cylindrical shell having an elongated earth contacting area extending axially of the shell and being arranged for rolling on the earth for compacting the same, a particulate ballast partially filling said, shell to approximately -97% of its capacity at maximum settled density of the ballast, the remainder of the volume of the shell being filled With air, said ballast containing a substantial portion of coarse, granular material and the remainder being fine powder particles having a fineness of 100 mesh or finer, the quantity of powder being suflicient to entrain the coarse material and maintain it air-borne on rotation of the shell, the amount of air enclosed in said shell being suflicient that during rotation of the tire the ballast is entrained in the air substantially filling the volume of the tire providing a balanced roller of a predetermined Weight, and scalable means for filling and emptying said shell.

2. Ballasted earth contacting equipment comprising an essentially air-tight, rigid cylindrical shell having an elongated earth contacting area extending axially of the shell and being arranged for rolling on earth for compacting the same, a particulate ballast partially filling the volume of said chamber leaving from 3 -20%. void at the top when the ballast is at maximum settled density, the void being filled with air, said ballast containing from 30-80% of a coarse granular material having a particle size from about one-eighth inch down to above about 100 mesh and the remainder of the ballast being a fine powder of at least about 100 mesh or finer, the amount of fine powder in the mixture being sufficient to suspend the coarse particles in the air during rotation of the shell so as to provide a balanced roller at a predetermined weight, and sealable means for filling and emptying said shell.

3. Ballasted earth contacting equipment comprising an essentially airtight, rigid cylindrical shell having an elongated earth contacting area extending axially of the shell and being arranged for rolling on earth for compacting the same, a particulate ballast partially filling the volume of said shell to approximately 80-90% of its capacity with the ballast at its maximum. settled density leaving a void 3-20% filled with air at the top of the shell, said ballast containing from 30-80% by weight of granular material of about 20 mesh and the remainder of -20% by weight of the ballast being a finely divided powder having a fineness of mesh or finer providing an airborne ballast and a balanced roller on agitation, and scalable means for filling and emptying said shell.

4. Ballasted eanth contacting equipment comprising an essentially air-tight, rigid cylindrical shell having an elongated earth contacting area extending axially of the shell and being arranged for rolling on earth for compacting the same, a particulate ballast partially filling said chamber at approximately maximum settled density thereof leaving a void of from 3-20% filled with air at the top of the shell, said ballast containing from 30-80% by weight of lead shot the particles of which have an average diameter of about one-eighth inch to 20 mesh and the remainder of the ballast composition being fine powder particles having a fineness of at least about 100 mesh whereby to provide an air-borne ballast so as to form a balanced roller on rotation of same, and scalable means for filling and emptying said shell.

References Cited in the file of this patent UNITED STATES PATENTS 1,088,582 Jarvis Feb. 24, 1914 2,038,653 Gilbert Apr. 28, 1936 2,410,465 Small Nov. 5, 1946 2,580,084 Donnelly Dec. 25, 1951 2,884,039 Hicks 'Apr. 28, 1959 FOREIGN PATENTS 694,101 Germany July 26, 1940 483,925 Italy a Aug. 25, 1953

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