Showing papers on "Screed published in 1974"

Extensible screed and auger assembly for a road paving machine

Abstract: The invention relates to a paving machine, and more particularly to an extensible screed and auger assembly for use thereon. The paver, which is self-propelled, includes a frame, a tiltable hopper having a discharge opening, a generally vertical center strike-off assembly connected to the frame and positioned rearwardly of the discharge opening, a pair of laterally extensible strike-off plates connected to the center assembly and a pair of rotatable augers positioned between the discharge opening and the strike-off plates. The augers are mounted on the side strike-off plates and coextend therewith relative to the center assembly.

Automatic support system for a screed

Abstract: An asphalt finishing machine includes a tractor and a screed of the free floating type wherein the latter is towed behind the tractor by a pair of draft arms pivotally connected at their forward ends to the frame of the tractor. A pair of hydraulic cylinders is connected to the tractor and to the screed for lifting the latter away from the roadway mat when the finishing machine is transported from one job site to another. A control system is connected with these cylinders and is automatically and instantaneously brought into operation, by means of a pressure-sensitive switch, whenever forward motion of the finishing machine is arrested, as when the hopper is being refilled, for actuating the hydraulic cylinders to develop a lifting force having a magnitude at least 80 to 90% of the force developed by the dead-weight of the screed thereby to prevent the screed from settling into the mat during such periods of time when forward motion of the finishing machine is stopped.

Self-propelled paver

Abstract: An asphalt paver has a suspension which, in normal use, applies much of the paver weight to the screed, but includes a provision for forwardly tilting on bogie assemblies, to raise the screed and spreading auger for highway travel. Main suspension frames are mounted beneath the hopper on trunnions and extend rearwardly to mount wheels aft of the center of gravity of the paver but forward of its lateral spreading auger. When jacks are operated downward to bear on the rear portions of the bogie suspension frames, they shift its weight distribution forward and lift the screed and spreading auger to permit highway travel.

Road maintenance machine and methods

Abstract: A road maintenance machine is provided with a heater assembly mounted on a general purpose chassis which is adapted for selectively attaching various road working devices. The heater assembly includes multiple rows of high temperature burner units each having means for burning fuel and projecting the generated heat downward against the road surface. The rows are spaced apart to allow the top of the surface to partially cool between burner rows as the heat penetrates the pavement in order to maintain the surface temperature below its flash point but high enough to achieve sufficient heat penetration to soften the pavement material to a significant depth. Heat shields and exhaust hoods are provided between the rows of burners to confine and direct the heat and combustion products. The chassis is provided with an adjustable hydraulic mechanism to which an asphalt planer, a scarifier assembly or a grooving cylinder may be attached to work the softened pavement material. An elevator is mounted at the rear of the machine to clear the roadway of planed material. An oscillating screed may be connected to the machine behind the scarifier assembly to smooth the worked surface. Methods are described for asphalt heating, asphalt planing, asphalt scarifying and asphalt grooving using the road maintenance machine.

Screed extensions for paving machines

Abstract: It is known to utilize a screed extension apparatus along the front surface of a mold board in a machine for spreading pulverulent material such as a paving machine. Such a screed extension apparatus normally includes a strike-off plate and means for mounting and moving this plate between a retracted position generally in front of the mold board and an extended position in which the strike-off plate extends from an end of the mold board so as to serve as an extension of the mold board. Such a structure can be improved by utilizing two housings, the second of which fits around the first in such a manner that the second housing may be moved linearly with respect to the first but is restrained from any other type of relative movement with respect to the first housing. The first housing is secured in front of the front surface of the mold board well above the bottom of the mold board and adjacent to the end of the mold board. The second housing carries the strike-off plate. Preferably a hydraulic cylinder is located in the first housing and is operatively connected to the second for use in moving the second housing relative to the first housing.

Slip form having hinged gate means

Abstract: A slip form or screed for forming elongated concrete formations, such as a highway barrier wall wherein a concrete receiving hopper is located forwardly of the slip form, and the front wall of the hopper is provided with a hinged gate pivotal between open and closed positions. The gate structure permits stationary objects to enter the hopper and slip form as to become a part of the formed concrete formation, and the gate structure includes concrete retaining means to confine the concrete when the gate is opened, and control the flow of concrete forwardly through the opening when stationary objects are received within the form.