Road structure – process – or apparatus – Apparatus – Screed or drag
Reexamination Certificate
2000-04-10
2001-11-27
Neuder, William (Department: 3673)
Road structure, process, or apparatus
Apparatus
Screed or drag
C404S092000, C404S098000, C404S102000
Reexamination Certificate
active
06322287
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention concerns equipment used for the grading of crushed rock or other aggregate preparatory to a paving operation.
In the construction of paved surfaces it is common practice to use a machine having a screed component for determining the thickness of aggregate of the sidewalk or roadway under construction. In the construction of sidewalks it is not feasible to utilize construction equipment intended for roadway construction. Instead it is current practice to employ a number of workers to rake or spread and configure aggregate prior to paving. Such a practice is costly from a man hour standpoint Secondly, non-uniform aggregate thickness often results from such effort As sidewalk specifications dictate aggregate thickness within a fairly narrow range, it is often necessary to re-accomplish at least partial spreading of the aggregate to meet specified depth. A further drawback to working aggregate manually is the quality of the aggregate is degraded in that working of deposited aggregate results in the smaller particles or fines thereof gravitating toward lowermost area of aggregate with the result that the top layer is largely devoid of fines or small particles. Desirably, aggregate is of uniform constituency throughout its depth with one object being that the concrete or other material when laid does not gravitate down through the aggregate but rather tends to lie for the most part on the uppermost surfaces of the aggregate to reduce the quantity of paving material used in the opeation without a reduction in the integrity of the finished paving.
U.S. Pat. No. 4,496,265 shows a self-propelled asphalt paving machine which is wheel supported with a laterally tiltable screed and requiring two operators if paving thickness is monitored.
U.S. Pat. No. 3,841,777 is of interest in that it includes a vibratory compactor, on a road surfacing machine with strain sensitive suspension to indicate the density of paving material and control the strike off height of a “skimmer” or screed to effect uniform density of “surfacing material”.
U.S. Pat. Nos. 3,396,642 and 2,951,427 show grading machines with trailed vibratory compactors.
SUMMARY OF THE PRESENT INVENTION
The present invention concerns equipment used for the grading of crushed rock or other aggregate preparatory to a paving operation.
The apparatus includes a highly maneuverable prime mover, preferably a tractor of the skid-steer type desirably having a tread dimension enabling travel between forms for sidewalk construction. A forwardly extending frame of the apparatus is mounted on the tractor and carries a blade or strike off at its forward end. A movably mounted shoe of plate configuration trails from the frame and rides upon the aggregate surface with adjustable actuators positioning the shoe including any transverse inclination or slope of the aggregate. The actuating means additionally serves indirectly to lift and lower the strike off edge of the blade to determine the depth of aggregate. Indicators for aggregate depth are provided to permit an operator to continually monitor the depth of aggregate being laid. Control means provided the operator permits convenient, simultaneous or individual actuator extension or retraction while under way to achieve specified aggregate depth. A vibratory compactor trails the plate shaped shoe by means of pivotal linkages to compact horizontal or inclined aggregate surfaces. The prime mover is preferably of the type including hydraulically actuated lift arms for imparting elevation to the apparatus for travel to and from a grading site.
Important objectives of the present invention include the provision of a machine suited particularly for the grading of sidewalk aggregate, but not restrictively so, heretofore done by costly manual labor with wide variances in aggregate depth often encountered; the provision of a machine for grading aggregate in one pass to preserve the homogenous nature of aggregate otherwise reduced by repeated working of the aggregate resulting in the aggregate fines gravitating to the bottom, leaving the uppermost layer of aggregate more porous than desired; the provision of a machine for effecting the desired depth of aggregate while maintaining its homogenous nature to effect a savings in the amount of concrete used in a paving operation; the provision of an aggregate grading machine enabling the single machine operator to continuously monitor and adjust aggregate depth during travel along a course; the provision of a grading machine readily transportable on a medium sized flat bed truck to a job site.
REFERENCES:
patent: 2951427 (1960-09-01), Moir
patent: 3396642 (1968-08-01), Martinson
patent: 3602115 (1971-08-01), Hanson
patent: 3841777 (1974-10-01), Domenighetti
patent: 3999314 (1976-12-01), Miller et al.
patent: 4395156 (1983-07-01), Sprague, III
patent: 4496265 (1985-01-01), Fragale
patent: 5156487 (1992-10-01), Haid
patent: 5344254 (1994-09-01), Sartain
patent: 5348418 (1994-09-01), Campbell
patent: 5638656 (1997-06-01), Roe
“Do It All”, Ingersoll-Rand Brochure, 1995.
Givnan, Jr. James D.
Neuder William
Singh Sunil
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