US3421419A

US3421419A - Placing of reinforcement in concrete roads and the like surfaces

Info

Publication number: US3421419A
Application number: US586728A
Authority: US
Inventors: Joseph N Adcock
Original assignee: United Steel Companies Ltd
Current assignee: United Steel Companies Ltd
Priority date: 1966-10-14
Filing date: 1966-10-14
Publication date: 1969-01-14
Anticipated expiration: 1986-01-14

Description

Jan. 14, 1969 I J. N. ADCOCK 3,421,419

PLACING OF REINFORCEMENT IN CONCRETE ROADS AND THE LIKE SURFACES File d Oct. 14, 1966 Sheet of 2 P i I I 2 (\IJ-\\, 0 f 5 2 Q 3 INVENTORS JOSEPH N. ADCOCK ATTORNEYS Jan. 14, 1969 J. N. ADCOCK 3,421,419

PLACING 0F REINFORCEMENT IN CONCRETE ROADS AND THE LIKE SURFACES Filed Oct. 14, 1966 Sheet of 2 INVENTOR JOSEPH Al. ADCOCK m AT TQBNEYS.

United States Patent 3,421,419 PLACING OF REINFORCEMENT IN CONCRETE ROADS AND THE LIKE SURFACES Joseph N. Adcock, Woodsetts, near Worksop, England, assignor to The United Steel Companies Limited of The Mount, Broomhill, Shefiield, England Filed Oct. 14, 1966, Ser. No. 586,728 US. CI. 9439 11 Claims Int. Cl. E01c 19/52; 21/00 ABSTRACT OF THE DISCLOSURE A paving machine for laying concrete roadways and having a tiltable sledge-like platform which supports and positions a reinforcing mesh in the freshly laid concrete as the machine is advanced along the roadbed. The platform is longitudinally displaceable on the machine so that it can be shifted out of the concrete and tilted to allow the exposed mesh to be secured to a structural joint assembly such as expansion and contraction joints.

When concrete roadway slabs and similar surfaces are constructed in one pass by means of a slip-form paver or similar machine, problems arise in the placing of mesh or other steel reinforcement which is normally positioned two or three inches below the top surface of the slab.

As the paving machine advances, the reinforcement must be introduced into the concrete mix at the correct level, supported to prevent its sinking in the fluidised concrete and restrained from rising to the surface due to any reaction from the consolidating vibrators or other upward impelling forces.

Any device used for achieving this object must also be capable of passing over the dowel bar and similar assemblies used at expansion and contraction joints which occur periodically transversely across the roadway.

The present invention provides a novel or improved machine or apparatus which overcomes these difliculties and makes possible the continuous introduction of reinforcement into concrete roads and like surfaces at the required level as the roads are being laid.

According to the invention there is provided upon or in association with a slip-form paver or similar machine a member operable, as the paver advances, to engage beneath prepositioned reinforcement and to deliver it simultaneously with the fluidised concrete to the road or carriageway at the required height above the sub-base or like surface. The mesh-engaging member comprises a platform which supports and positions the reinforcing mesh and which is tiltable to adjust the height at which the mesh is positioned in the laid concrete. The platform is also displaceable longitudinally of the paving machine so that it can be withdrawn from the freshly laid concrete to allow the mesh to be secured to expansion and concrete joints and the like.

In order that the invention may be more fully understood reference will now be made to the accompanying drawings which illustrate a preferred embodiment thereof and wherein FIG. 1 is a diagrammatic longitudinal section of the forward end of a slip-form paver incorporating the reinforcement laying mechanism, shown here in the normal operative position, and

FIG. 2 is a similar view but with said mechanism depressed for a purpose hereafter explained.

In the drawings there is shown the forward end of a slip-form paver including the throat I of the hopper through which the fluidised concrete is delivered onto the sub-grade or like surface, the reinforcement elevating and placing device 2 being located between a pair of forwardly- Patented Jan. 14, 1969 projecting side forms or frame members 3 spaced at a width corresponding to the width of the road being laid.

The reinforcement is normally in the form of mats of welded steel mesh which are restricted in width for practical reasons and on a normal roadway it is customary to have several widths of mesh within the roadway width. For the purpose of the invention the mats of mesh in each line or row are joined together to form a continuous strip 4 by overlapping adjacent ends and tying with wire. The mats are preferably discontinuous or spaced at all joint assemblies but may be linked by tie wires, nylon cords or the like, said mats being pre-assernbled on the sub-base or equivalent surface prior to the approach of the reinforcement placing device.

The device 2 comprises a platform or sledge 5 pivotally mounted at its forward end on a carriage 6 fitted near its upper end with spaced rollers 7 which run in fixed channel or similar guides 8. As the paver advances, the sledge travels beneath the continuous strip of mesh and positions it at the required height for laying in the wet concrete, the machine preferably including a pre-lifter in the form of a rigid bar or tube 9 mounted transversely at the front of the machine at such height that the mesh strip is guided without excessive flexing over the sledge. The transverse width of each sledge corresponds to the width of the steel mesh being used and one, two, three or more sledges are used in line transversely across the road.

Projecting rearwardly from the sledge is a series of spaced parallel fingers 10 which, when the sledge is in the position shown in FIG. 1, extend into the wet concrete in the zone of the hopper throat to support and discharge the mesh at the desired level. The vertical height of these fingers can be adjusted by moving the sledge about its pivotal connection 11 with the carriage 6. In the arrangement shown, a pair of hydraulic rams 12 are used for this purpose, said rams being pivotally supported at one end on the machine frame and having operative connection at the other end with the upper ends of side plates 13 fixed to the sledge, but it will be understood that any equivalent means may be used for varying the angular position of the sledge and supporting fingers.

Positioned transversely across the throat of the hopper above the line of travel of the mesh strip is a series of depressor blades 14 which prevent the mesh rising into contact with other parts of the machine, said blades being adjustable in height for which purpose they are secured at their forward ends on a transverse shaft 15 which can be rotated, for example, through rod and lever arm 16, by hand lever, hydraulic ram or other manual or poweroperated means. The blades 14 preferably have the boomerang shape shown and may each consist of two sections pivotally interconnected at 17 and capable of relative angular adjustment.

It will be appreciated that control of the height of the reinforcement is achieved by inclining the sledge and adjusting the depressor blades and, where the laid road includes construction joints embodying dowel bar or similar assemblies, one such assembly being shown at 18, the sledge will normally clear these assemblies. However, where necessary, the sledge can be raised to a horizontal position to clear a joint.

In use it has been found desirable at each joint assembly, or at intervals such as every third joint, to secure thereto the leading edge of the succeeding section of mesh. For this purpose and on reaching the far side of a joint, the paving machine is stopped and the sledge is moved forward by traversing the carriage 6 along the channel guides 8. In the drawings, we have shown chain and sprocket gear 19 for this purpose but hydraulic, electric or any other manually or power-operated means may be used. The sledge is now tilted to the position shown in 3 FIG. 2 and this makes possible the attachment by ties or equivalent means of the leading edge of the mesh to a transverse bar 20 welded to the joint assembly for this purpose. As the machine proceeds, the sledge is returned to its previous position relative to the machine.

It will be understood that whilst the invention has been described in relation to its use with mesh type reinforcement, with minor modification the device can be adapted for handling rods and other type of reinforcement capable of forming a continuous strip.

I claim:

1. An apparatus for laying reinforcement in a concrete roadway or like surface in conjunction with a slip form paver or similar machine, comprising a platform operable as the paver advances to supportingly engage beneath and position a concrete reinforcement structure in freshly laid concrete and to deliver it simultaneously with the fluidised concrete to the roadway at the required height above the subbase or other surface receiving the concrete, and a series of blades engaging the top surface of said reinforcement structure to maintain the reinforcement structure depressed a predetermined level below the top surface of the concrete.

2. The apparatus defined in claim 1, wherein said platform has a series of fingers projecting into the zone at which the fluidised concrete is delivered to the road surface.

3. The apparatus defined in claim 2, wherein the platform is selectively tiltable to adjust the height of the delivery end of said fingers.

4. The apparatus defined in claim 3, including a prelifter device positioned in advance of the platform and operable to elevate the reinforcement structure and to guide it onto said platform.

5. The apparatus defined in claim 3 wherein said fingers extend into the zone of the throat of the concrete delivery hopper.

6. The apparatus defined in claim 1, wherein said blades are vertically adjustable.

7. The apparatus defined in claim 6, wherein said blades have the form of lever arms which are mounted on a rockable shaft for common movement.

8. The apparatus defined in claim 7 wherein said blades are each formed of two parts pivotally interconnected for relative angular adjustment.

9. The apparatus defined in claim 1 wherein said platform is suspended from a carriage which is selectively longitudinally displaceable on the machine.

10. In combination with a slip-form concrete paving machine for laying a continuous concrete roadway as it advances along the sub-base over which the concrete is laid, an apparatus carried by said machine for laying a concrete reinforcing structure in the concrete roadway as it is laid comprising a platform for supporting and positioning said structure at a predetermined height in the concrete as it is laid, and means supporting said platform in said machine for selective longitudinal displacement relative to said machine to enable said platform to be withdrawn from the laid concrete while still supporting and positioning the reinforcing structure to be embedded in the concrete.

11. The combination defined in claim 10 comprising means for pivoting said platform about an axis extending transversely of the longitudinal axis of said machine to position said platform for adjusting the height at which said structure is disposed above said sub-base.

References Cited UNITED STATES PATENTS 1,895,991 1/1933 Heltzel 94-46 2,123,989 7/1938 Day 94-46 2,225,015 12/1940 Lebelle 94-46 2,996,963 8/1961 Stultz 94-39 3,161,117 12/1964 Supject 94-46 3,261,272 7/1966 Jennings 94-46 3,274,906 9/ 1966 Worson 94-46 X NILE C. BYERS, JR., Primary Examiner.

US. Cl X.R.