US2842036A - Compacting and spreading device for highway surfacing materials - Google Patents

Description

I. J. OVERMAN July s, 1953 COMPACTING AND SPREADING DEVICE FOR HIGHWAY SURFACING MATERIALS Filed Nov. 23, 1955 United States Patent O COMPACTING AND SPREADING DEVICE FOR HIGHWAY SURFACING, MATERIALS Ivan J. Over-man, Marion, Ind. 7 Application November 23, 1953, Serial No. 393,609 r 1 Claim. c1. 94- 46) This invention relates generally to apparatus for laying highway surfacing materials, and moreparticularly it relates to apparatus for vibrating portions of a material spreading and laying machinein order to increase the speed of laying the material and in order to improve the quality of the surface of the material after it is laid.

Conventional spreaders orpavers usually consist of a hopper adapted to receive highwaysur'facing materials. The hopper is mounted ona frame which rides on guide wheels and rollers. The entire apparatus may be hitched to a dump truck whereby'the'froad surfacing material may be continuously fed into the hopper of the spreader, and the truck may tow the spreader at auniforhi rate, spreading highway surface material 'in 'a'acontinuous stream. Spreaders of this type are usually provided with a screed which is supported from the frame of the spreader immediately behind the hopper for levelling the surfacing material and controlling the thickness of the material laid on the highway. In some cases the screed is not moved in any way during a material levelling operatic-n, while in other cases the screed is oscillated ina'horizontal plane. Neither method of operation has beenfound to be completely satisfactory due to the fact that the levelling action of the screed requires a minimum" time period per linear foot of movement, thereby limiting the speed of travel of the spreader. Furthermore, screeds operated in accordance with conventional methods do not create a smooth and level highway surface due to the fact that there is insufficient compacting action whereby some areas of the highway material may be laid with sufficient compaction, whereas other areas are not sufiiciently compacted. As a result, what appears to be a smooth surface when the material is laid will subsequently became rough or bumpy after the surfacing material has become compacted by trafiic.

Accordingly, the principal objectof this invention is to provide highway surfacing apparatus wherein the screed plate thereof is operated to provide positive compacting action with respect to the surfacing material.

A further object of the invention is to provide highway surfacing apparatus having a screed plate which may be operated to level and compact the surfacing materials at a faster rate than possible with prior art apparatus.

In accordance with this invention there is provided apparatus for laying road surfacing material comprising a hopper having a material discharge throat at the bottom thereof, a screed plate cooperating with the hopper for providing a layer of surfacing material of predetermined thickness and including a material guiding plate disposed in over-lapping relationship to the throat portion of said hopper, and a vibrator mounted on one Wall of the hopper for vibrating the hopper and the screed plate, thereby to impart compacting action to the screed plate and to increase the rate of levelling and compacting of the highway surfacing material.

The full nature of the invention will be understood from the accompanying drawings and the following description and claim:

application of this invention 2,342,035 Patented July 8, 1958 Fig. 1 is a rear perspective view of the highway surfacing material spreader provided in accordance with this tangular frame 10 on which is mounted a material receiving hopper 11, together with a rotatable roller 12. The hopper 11 is triangular in cross section and includes a forward wall 14, together with a rear wall 15, the walls converging downwardly toward one another to form a material discharge throat 16. Hopper 11 may be mounted 011 frame 10 in any conventional fashion.

The roller 12 is divided into two rolls in accordance with conventional practice, whereby a concave or a convex highway surface may be rolled. The roller is provided with a cocoa mat 18 further in accordance with conventional practice, and the water tank 19is mounted on the rear wall 15 of the hopper 11 for supplying water to the right and left hand portions of the cocoa mat 18 through pipes 20, 21, 22 and 23, respectively. While the rear end of the spreader is illustrated asbeing supported on the roller 12, it. will be understood that the forward end of the frame 10 may be supported on wheels or casters (not shown) in accordance with conventional practice. The structure described thus faris conventional in every way and is disclosed in order to clarify the to highway surfacing material Spreaders.

The screed plate 25 is pivotally mounted below the throat of hopper 11 by means of a set of hangers 26 which may be suitably fastened to frame 10 at 27. The screed plate 25 is divided into two portions (not shown) in a being supported by a pair of hangers 26. The screed plate includes an upstanding bafllle member 28" which extends relationship of baffle 28 and lip 29 is important in carrying outthis invention, as will be described in connection with the functioning of the apparatus.

In order to permit adjustment of the height of the screed plate 25, a plurality of spring members 30, 31 and 32 are connected to the upper edge of bafllle 28 and suspended by chains such as 33 on hook members 34, the chain providing means whereby different degrees of tension may be placed on springs 30.

Additionally, for adjusting the height of the screed plate 25 with respect to the highway surface, the screed plate is suspended adjustably by means of hangers 36, 37 and 38 which in turn are pivotally connected to adjusting levers such as 39 and 40. Hangers 36 and 38 support the outer ends of the screed plate while hanger 37 supports the inner ends thereof. Levers 39, 40 are pivotally connected at their ends to semicircular plate members 41 and 42 mounted onwall 15 of the hopper, these plate members having a series of holes 43 adjacent their outer edges for receiving stop pins, whereby the levers may be lifted or lowered until the screed plate is positioned at the desired height, after which the pins such as pin 44 may be passed through the levers and the holes 43 to lock the levers in adjusted position. It will be understood that the lever at the right hand end of hopper 11 is obscured by tank 19 and that its structure is identical with that of the lever and mounting structure 39, 41, 43 and 44. In order to permit the springs 30, 31 and 32 to carry a certain portion of the weight of screed plate 25, and in order to permit vibratory motion of screed plate 25, the holes 43 are ovcrsized with respect to pins 44, whereby one-quarter inch to one-half inch of upward and downward play of the screed plate may occur, even though the levers 39 and 40 are pinned to the plates 41 and 42.

For imparting vibratory motion to the rearwall 15 of the hopper 11, and also to the screed plate 25 and its baflle 28, there is provided a vibrator consisting of a shaft 46 mounted in pillow blocks 47 on wall 15,

the shaft being provided with off center weights 48 and a 49. For rotating the shaft 46 and therewith the'weights 48 and 49, there is provided an engine 50 mounted, on a shelf 51 projecting outwardly and horizontally from the wall 15, the engine 50 driving shaft 46 through the pulley and belt connection 52.

In operation the spreader may be pulled in a forward direction behind the dump truck with the hopper 11 receiving surfacing materials; such as stone, gravel and hot or cold asphalt mix. The height of the screed plate 25 above the surface of the highway may be adjusted by means of the levers 39 and 40, whereby the screed plate is adjusted within one-quarter to one-half inch of the desired thickness of the surfacing material. Thus, the screed plate hangs on springs 30, 31 and 32. With the engine running and the vibrator shaft 46 rotating, the rear wall 15 of hopper 11 is set into vibration. Shaft 46 may be rotated at any speed between three hundred R. P. M. and twelve hundred R. P. M., depending upon the nature of the material being spread. As the material falls through the throat 16, and as the screed plate 25 pushes the material forward, there is a tendency for material to be forced between bafile 28 and the outer edge of the lip 29, thereby providing a connection between these two elements. In this manner, the vibration of wall 15 is transmitted to baffle 28 and screed plate 25, and because of the onequarter inch to one-half inch play provided in the adjustable supporting structure 39, 41, 43 and 44, together with springs 30, 31, 32, the screed plate 25 receives vibratory motion from wall 15. The effect of this vibratory motion is to cause the surfacing material to be compacted by the screed plate and to be settled into any cracks or cavities in the highway surface. Thus, after the screed plate 25 has passed over an area, the newly laid layer of surfacing material has uniform density or compaction, regardless of irregularities in the original highway surface. Furthermore, this compaction occurs at a higher rate of speed than is possible using conventional apparatus.

Consequently, the material spreading apparatus provided in accordance with this invention has increased capacity to the extent that it can be moved in a forward direction at a higher rate of speed, laying a greater volume of surfacing material.

The invention claimed is:

Apparatus for laying highway surfacing material comprising a frame, rotatable means for supporting said frame, a hopper mounted on said frame and having front and rear walls converging downwardly to form a material discharging throat at the bottom thereof, a screed plate positioned behind and below the rear wall of said hopper and including a bafille member extending upwardly into overlapping relationship with the lower edge of the rear hopper wall, whereby highway surfacing material pushed in front of said baffie may form a vibration transmitting connection between the rear of said hopper and the upper portion of said bafile, means for adjustably mounting said screed plate on said frame with apredetermined degree of play in a vertical direction, said means including members pivotally suspending the rear edge of the screed plate from the frame, spaced brackets mounted on the rear hopper wall, spaced pivotal links for suspending the forward edge of'said screed plate from the brackets, said brackets each, having a plurality of enlarged openings therein receiving a pin of reduced diameter at the upper end of the links permitting movement within the limits of clearance thereby provided, and tension springs con necting the forward edge of said screed plate to the rear hopper wall, thereby resiliently supporting said plate for vibratory movement, and means supported on the rear wall of said hopper for vibrating said wall and therewith said screed plate.

References Cited in the file of this patent UNITED STATES PATENTS 2,035,627 West Mar. 31, 1936 2,049,115 Hadley July 28, 1936 2,072,479 Hadley Mar. 2, 1937 2,136,917 French Nov. 15, 1938 2,251,095 Wood July 29, 1941 2,332,688 Baily Oct. 26, 1943 FOREIGN PATENTS 2,136,917 France Nov. 15, 1938

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