Showing papers on "Screed published in 1973"

Towed paver with thickness and leveling control

Abstract: A towed paver for use with a dump truck has a fixed hopper and screed and vertically adjustable support wheels and sensors engaging a supporting surface on which the wheels travel controlling devices moving said adjustable support wheels to control the thickness and level of an asphalt mat laid by the paver.

Screed attached grade reference mechanism

Abstract: A mobile grade reference device is connected to the paving machine for travel therewith, such grade reference device being disposed forwardly of the screed and inboard of the lateral extremities thereof. A longitudinally extending grade reference beam has the forward end thereof pivotally mounted to the mobile grade reference device at the longitudinal midpoint of the latter, such pivot point being located rearwardly of the pivot axes of the draft arms engaged with the screed. The rearward end of this beam is pivotally mounted to the screed. The control system for raising and lowering the pivot axes of the draft arms has the sensor thereof supported from the screed adjacent to and forward of the forward portion of the screed; this sensor is engaged by a stringline mounted on said beam.

Reference beam grade control for asphalt pavers

Abstract: The disclosure relates to an improved type of grade control for an asphalt paver utilizing reference members positioned in leading and trailing relation to the pavement-forming screed. Control over the grade of the asphalt mat laid down by a floating screed is controlled by the combined action of the reference members moving along with the paving apparatus and sensing the average grade conditions of the base in front of the screed as well as the average grade conditions of the newly laid pavement mat. The new control provides for exceptional smoothness and uniformity of the pavement mat, and also greatly facilitates the use of mobile grade reference controls when laying extremely wide pavement mats.

Apparatus for sensing twisting of a paving machine screed

Abstract: Apparatus for sensing twisting of a screed of a paving machine, the paving machine having a control system for changing the angle of attack of of each end of the screed relative to a road surface. The twist-sensing apparatus includes a sensor adapted to be mounted on the screed for sensing twist in the screed, the sensor comprising a signal generator for generating a signal in response to the screed twisting from a predetermined twist angle, this signal being adapted to effect energization of the control system for changing the angle of attack of one end of the screed thereby to restore the screed to its predetermined twist angle. The signal generator is rigidly secured to and is movable with the screed at a first location on the screed. The sensor further comprises a twist reference arm rigidly secured to and movable with the screed at a second location on the screed angularly displaced from the first location. The twist reference arm extends obliquely relative to the screed between the first and second locations, and is operatively connected to the signal generator, whereby a change in screed twist causes relative movement between the signal generator and the twist reference arm and thus generates a signal upon the twist angle of the screed deviating from its predetermined twist angle.

Convergent link system for connecting a screed to the traction unit of a paving machine

Abstract: An upper pair of arms is pivotally connected at its forward and rearward ends to the screed and to the rear portion of the traction unit. A lower pair of arms is pivotally connected at its forward and rearward ends to the screed and to the rear portion of the traction unit. Imaginary extensions of the upper and lower pairs of arms converge and intersect at points defining a transversely extending effective tow axis, which axis is disposed adjacent the subgrade and forwardly of the rearwardmost extremity of the traction means supporting the traction unit.