US3252390A

US3252390A - Concrete paving machine

Info

Publication number: US3252390A
Application number: US270070A
Authority: US
Inventors: Edwin O Martinson
Original assignee: Koehring Co
Current assignee: Koehring Co
Priority date: 1963-04-02
Filing date: 1963-04-02
Publication date: 1966-05-24
Anticipated expiration: 1983-05-24

Description

May 24, 1966 E. o. MARTlNsoN 3,252,390

CONCRETE PAVING MACHINE Filed April 2, 1963 2 Sheets-Sheet l INVENTOR. En w//v O. MHf//Vfo/V ATTORNEY May 24, 1966 E. c. MARTlNsoN CONCRETE PAVING MACHINE 2 Sheets-Sheet 2 Filed April 2, 1965 Epw//v 0. M/qer//vfon/ BY /LZK TM INVENTOR.

A fraz/VE Y United States Patent O ring Company, Milwaukee, Wis., a coi-poration of Wisconsin Filed Apr. 2, 1963, Sei'. No. 270,070 8 Claims. (Cl. 94-45) This invention relates generally to concrete paving machinery and finds particular utility in paving machinery of the single pass type. More specifically, `the present invention relates to improved mechan-ism just ahead of the screed which prevents the concrete from boiling up behind the screed as the machine moves along and lays the finished pavement.

`In single pass paving machines where the present invention finds considerable utility, it is essential that the concrete being leveled off ahead of the screed is prevented Ifrom building up which usually results in excess concrete working itself under the screed and prevents continuous, one-pass operation. In addition, this excess concrete build up ahread of the screed causes that concrete behind the screed, which is supposedly at the finis-hed grade, to boil up and thereby require an additional pass of the machine or other operations on this area.

Prior attempts have been made to eliminate this problem but have not proven to be satisfactory. F or example, strike od .blades or plows have been used to level the excess concrete and push it ahread of the finishing screed. In. addition, vibrators of various types have been used to compact and settle the concrete in place just ahead of these strike off blades. It should also be mentioned that these vibrators have the inherent ability to render the concrete quite iiuid. These devices, however, have not 3,252,39@ Patented May 24., ieee Still a more limited aspect of the invention relates to providing a paddle wheel of the above type with a separate drive so that it can rotate continuously and independently of forward movement of the machine.

These and other objects and advantages will appear hereinafter as this disclosure progresses, reference being had to the accompanying drawings, in which:

FIGURE l is a side elevational view of a concrete paving machine embodying the present invention, certain parts being shown as in section or broken away for clarity;

FIGURE 2 is a fragmentary plan view of a portion of the device shown in FIGURE l, certain parts being lbeen successful in one pass machines, and the previously mentioned build up of excess concrete under the screed and/or boil up behind the screed have occurred notwithstanding many and various attempts in the industry to eliminate these problems.

Accordingly, the present invention provides a one pass dle Iwheel immediately in front of the screed `which is positively rotated so that its lower side is moving in the direction of -machine travel. This wheel is furthermore positioned in a vertical direction so that its lower limit is -closely adjacent or at the finished grade. The arrangement is such that the concrete is compacted in place below the finished grade level by the vibrator, and then the paddle wheel acts to pus-h or propel the excess concrete well in front of the screed.' This particular construction and arrangement of parts results in the a-bility of the machine to operate continuously with only one pass and without any undesirable pressure build up of concrete under the screed and/ or boiling up behind the screed. This improved operation occurs even though a vibrator is used ahead of the screed and which renders the concrete quite iiuid. In either event, the excess concrete immediately ahead of the screed is removed by the positively rotating paddle wheel, and the weight of this excess concrete is no longer effective to force Ithat concrete behind the screed to boil up and ruin the finished surface.

A more specific aspect of Ithe present invention relates to an improved machine of the above type in which the paddle Wheel has a series of circumferentially spaced and rearwardly raked paddles or blades which act not only to lift and push the excess concrete forwardly 'with no carry over of the concrete, but also functions to tear off the excess concrete above the grade to be finished.

shown .as in section, broken away or removed;

FIGURE 3 is a fragmentary side elevational view, in section, of a portion of the machine as shown in FIG- URE l, but on an enlarged scale; and

FIGURE 4 is afront elevational view of a modified form of paddle wheel.

' The present invention is applicable to various types of paving machines, such as for example, the slip-form type or that type which uses the forms as tracks or rails to guide and support the machine.

Referring in greater detail to the drawings, the main frame F of the paving machine M is guided `by any suitable running gear over the prepared ground G on which the paving is to -be laid. Such running gear may take the form of vertically adjustable gauge wheels (not shown) which maintain the machine at the proper attitude to the ground. Alternatively, guide means for the running gear may consist of the concrete forms l which are secured to the ground and repeatedly moved ahead to form the upper limit of the finished paving. In the latter case, the machine frame F has wheels 2 which roll along these forms. l

The machine also includes a power plant 3 which may be of the internal combustion type and which not only serves to propel the machine (hydrostatic drive not shown) over the prepared ground in the conventional manner, but also serves as the power source for other components of the machine, as will appear. A conventional cross conveyor i acts to deliver concrete to the swingable spreading conveyor 5 which is also conventional and acts to deliver the concrete across t-he width of the strip to be paved and in front of a vibrator 6, if a vibrator is used in this location.

The vibrator 6 extends across the entire width of the strip to be paved and its lower edge is located at the finished grade of the paving. The vibrator may be driven in the conventional manner from the power plant 3 by the drive means '7. While the vibrator acts to settle the concrete and compact it into position belowy the surface of the finished -road or grade it also has the effect of putting the concrete in a fiuid state which further aggravates the problem of the concrete boiling up behind a stationary screed 9, even though the screed itself may be doing a satisfactory job. In any event, the weight of excess concrete located immediately ahead of the finishing screed 9 would force the supposedly finished concrete behind the screed to boil up and ruin the surface. This boiling up phenomenon occurred even though the screed was of considerable length in a fore andl aft direction.

The machine also includes reciprocatory finishing belts I0 and 11 located to the rear of the screed.

Located immediately in front of the screed 9 and in effect forming a continuous finishing surface therewith, is a narrow oscillating screed 12 that is driven from the power plant 3 by the conventional crank drive means D.

The screeds 9 and 12 may be considered as a single screed and they are both warped together to assume the desired contour or crown of the finished grade. This warping is accomplished in the conventional manner by the vertically adjustable rods R that are attached at their corner ends at spaced locations along the length of the screeds. The upper ends of the rods R are secured to the vertically adjustable mechanism 13.

In accordance with the present invention, a positively driven, rotary member in the form of a rotatably driven paddle wheel W is located immediately ahead of the screeds and preferably as close thereto as possible, and this wheel extends across the entire width of the strip to be paved.

As shown in FIGURE 2, this rotary member may be made in vertically

adjustable sections

14, 1S and 16 so their lower sides may approximately conform to the desired cross sectional contour of the finished paving. Vertical adjustment of the ends of the sections may be made by changing position of the sections in their ver tical frame support members 18, through links 19. The sections may be adjusted through shaft 19a along with the screeds to form the proper parabola or other desired shape.

The

sections

14, 15 and 16 of the rotary member W are driven from the power plant 3 through the power shaft S and its pulleys 20, and through endless belts 21 to the pulleys 22 fixed on the shafts 23 of the sections. This drive is independent of the drives to the other parts of the machine so that the paddle wheel can rotate even though the other parts or the machine itself is stopped, and this has `been found to be important.

The direction of rotation of the paddle wheel is in4 dicated by the curvilinear arrow in FIGURE 3 and the bottom side of the wheel moves in the same, direction as the forward travel of the machine.

The wheel comprises a central tube 24 having a series l of circumferentially spaced blades 25 secured thereto and extending along the length thereof. Preferably, eight blades are equally spaced around the tubular part 24.

These blades are inclined rearwardly in respect to the direction of rotation of the wheel and this inclination or rearward rake prevents the concrete from being carried over the top of the wheel. Preferably, the blades are inclined about 30 degrees from radial.

The lower edges of these blades at the bottom portion of their travel are located on a level near the bottom surfaces of the screeds 9 and 12, or the finish `grade level. With this arrangement, excess concrete which is located above the finish grade level is pushed forwardly and away from the screed. The result is to remove the weight of the excess concrete from the area adjacent the screeds and eliminates pressure on the concrete beneath the screed and more particularly to the rear of the screed, thereby boiling up of the concrete is prevented. Furthermore, the accumulation or forcing of excess concrete under the screed, and which causes the screed to rise out of its proper finishing position, is prevented.

If a vibrator 6 is used, the excess concrete is pushed by the paddle wheel on top of the vibrator or ahead of it and into a pile 27 as indicated in FIGURE 3.

Machines embodying the present invention may travel at various speeds, but a speed of 11/2 to 12 feet per minute is not unusual. At the lower speeds, say 3 feet per minute, a paddle wheel having a diameter of 16 to 18 inches and rotating at a speed of l r.p.m. has proved to be conditions. In other words, these curved blades do not contact the concrete as abruptly, as do the straight blades. However, the amount of pitch or lead on these blades is small so as to hold any lateral or sideways shifting of the concrete to a minimum.

The present invention provides a positively driven rotary drum-like member immediately in front of the screed and which forcibly pushes that excess concrete located above the finish grade well ahead of the screed. The action of the rotary member is to help define the finish grade of the pavement and relieve the pressure on the finished concrete located behind the screed. The result is a smoothly operating and efiicient, one-pass paving machine.

Various modes of carrying out the invention are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

I claim:

1. A concrete road paving machine comprising, a main frame, running gear adapted to support said frame for movement over a road site to be paved, a transverse screed carried by said main frame and presenting a bottom surface for cooperative engagement with concrete deposited on the road site ahead of said screed, and a transverse rotary member located immediately in front of said screed and closely adjacent thereto, said member having its lowermost side located on a level closely adjacent said bottom surface of said screed, and means for rotatably driving said member in a direct so that said lowermost side moves in the direction of normal machine travel to thereby push excess concrete above said level forwardly and away from said screed.

2. A concrete road paving machine comprising, a main frame, running gear adapted to support said frame for movement over a road site to be paved, a transverse screed carried by said main frame and presenting a bottom surface for cooperative engagement with concrete deposited on the road site ahead of said screed, a vibrator located ahead of said screed, and a transverse rotary member located rearwardly of said vibrator and immediately in front of and closely adjacent said screed, said member having its lowermost side located on a level closely adjacent said bottom surface of said screed, and means for rotatably driving said member in a direction so that said lowermost side moves in the direction of normal machine travel to thereby push excess concrete above said level forwardly and on said vibrator.

3. A concrete road paving machine comprising a main frame, running gear adapted to support said frame for movement over a road site to be paved, a transverse screed carried by said main frame and presenting a bottom surface for cooperative engagement with concrete deposited on the road site ahead of said screed, and an elongated paddle wheel extending transversely and immediately in front of said screed and closely adjacent thereto, said wheel having a series of circumferentially spaced paddles therearound adapted to pass closely adjacent the level of said bottom surface, and means for rotatably driving said wheel in a direction so that said paddles when at their lowermost position move in the direction of normal machine travel to thereby push excess concrete above said level forwardly and away from said screed.

4. A device as defined in claim 3 further characterized in that said paddles have a rearward rake in respect to the direction of rotation of said wheel to thereby prevent carry over of concrete around said wheel.

5. A concrete road paving machine comprising a main frame, running-gear adapted to support said frame for movement over a road site to be paved, a transverse screed carried by said main frame and presenting a bottom surface for cooperative engagement with concrete deposited on the road site ahead of said screed, a vibrator located ahead of said screed, and an elongated paddle wheel located rearwardly of said vibrator and immediately in front of said screed and closely adjacent thereto, said Wheel having a series of circumferentially spaced paddles therearound adapted to pass closely adjacent the level of said bottom surface, and means for rotatably driving said wheel in a direction so that the lowermost paddles move in the direction of normal machine travel to thereby push excess concrete above said level forwardly and away from said screed and over said vibrator.

6. A single-pass concrete road paving machine comprising, a main frame, running gear adapted to support said frame for movement over a road site to be paved, conveyor means on said frame for depositing concrete across the width of the road site, a transverse screed carried by said main frame rearwardly of said conveyor means and presenting a bottom surface for cooperative engagement with concrete deposited on the road site ahead of said screed, and a transverse rotary member located immediately in front of said screed and closely adjacent thereto, said member having its lowermost side located on a level closely adjacent the said bottom surface of said screed, a power plant carried by said main frame for propelling the machine, and a drive connection from said power plant to said member for rotating the latter independently of forward travel of the machine and in a direction so that said lowermost side moves in the direction of normal machine travel to thereby push excess concrete above said level forwardly and away from said screed.

7. A single-pass concrete road paving machine comprising, a main frame, running gear adapted to support said frame for movement over a road site to be paved, conveyor means on said frame for depositing concrete across the width of the road site, a transverse screed carried by said main frame rearwardly of said conveyor means and preventing a bottom surface for cooperative engagement with concrete deposited on the road site ahead of said screed, a vibrator locatedAahead of said screed, and a transverse rotary member located rearwardly of said vibrator and immediately in front of and closely adjacent said screed, said member having its lowermost side located at a level closely adjacent said bottom surface of said screed, a power plant carried by said main frame for propelling the machine, and a drive connection from said power plant to said member for rotating the latter independently of forward travel of the machine and in a direction so that said lowermost side moves in the direction of normal machine travel to thereby push excess concrete above said level forwardly and on said vibrator.

8. A concrete road paving machine comprising, a main frame, running gear adapted to support said frame for movement over a road site to be paved, a stationary transverse screed carried by said main frame and presenting a bottom surface for cooperative engagement with concrete deposited on the road site ahead of said screed, an oscillatory screed immediately in front of said stationary screed and forming a continuous finishing surface therewith, and a transverse rotary .member located immediately in front of said oscillatory screed and closely adjacent thereto, said member having its lowermost side located on a level closely adjacent the plane of said finishing surface, and means for rotatably driving said member in a direction so -that said lowermost side moves in the direction of normal machine travel to thereby push excess concrete above said level forwardly and away fromsaid screeds.

References Cited by the Examiner UNITED STATES PATENTS 1,554,072 9/ 1925 Durrenfeld 94-46 1,632,969 6/ 1927 Horner 94-44 1,760,442 5/ 1930 Robb 94-45 X 2,303,336 12/1942 Day 94-46 2,332,688 10/1943 Baily 94-46 2,333,041 10/ 1943 Poulter 94-48 X 2,481,679 9/ 1949 Miller 94-44 2,597,221 5/ 1952 Barber 94--46 2,645,986 7/ 1953 Rasmussen 94-44 2,796,811 6/ 1957 Barber 94-46 3,098,415 7/ 1963 Guntert 94--46 JACOB L. NACKENOFF, Primary Examiner.

CHARLES E. OCONNELL, Examiner. N. C. BYERS, Assistant Examiner.