Showing papers on "Screed published in 1972"

High energy screed for a paver or the like

Abstract: The trailing portion of the screed is connected to the draft arms by leaf springs contained in a vertical transverse plane. The upper ends of the springs are rigidly secured to the draft arms; the lower ends of the springs are connected to the screed by a horizontal, transverse pivot. Vibrators are mounted on the screed adjacent the leading portion thereof. Vertically disposed coil springs have their lower ends engaged with the vibrators for imparting a downward force thereto. The upper ends of these springs support weights, which weights are freely supported by vertical walls mounted from the draft arms.

Machine for vibrating, leveling and screeding concrete in a form

Abstract: A self-propelled, automated machine for operating over a form to which concrete is introduced, the main functions of the machine being to level, vibrate and screed the concrete to provide a concrete slab without voids, and especially a slab in which both upper and lower surfaces, as well as opposite side edges and other sectional configurations are finished.

Paving vibratory finishing machine having a device for constant compaction of the deposited layer

Abstract: A road surfacing machine of the full floating type applies road surfacing material and then levels the same. In order to make sure that the density of the surfacing material is uniform despite irregularities in the contour, the machine detects the pressure between a pressor member and the surfacing material. When the pressure decreases, thereby indicating less density, then a screed or the like is raised to increase the quantity of deposited material in that region; and when the pressure increases, the screed or the like is lowered to decrease the quantity of material.

Screed extension assembly for asphalt paving machine

Abstract: Disclosed are interlocking extension units for extending the screed of an asphalt paving machine. Each extension unit has an open inner end having two rotatable shafts extending vertically there across. A cylindrical cam is welded to each of the shafts in an off-center position. Disposed about each of the cams is a steel ring having a bolt extending radially therefrom beyond the inner end of the unit, the bolt being adapted to be connected to a slotted plate in the outer end of an adjacent unit. Also protruding from the inner end of each unit are two adjustable guide studs each of which is adapted to mate with the slotted plate to facilitate alignment of adjacent units and provide a limiting surface against which an adjacent unit is drawn when the cams are rotated.

Method and apparatus for providing grade control for the screed of a paver or the like

Abstract: A mobile grade reference device includes first means for sensing the vertical distance between successive points along a predetermined path on the subgrade and a grade reference point on such grade reference device. Second means are provided for continuously generating and storing first intelligence representative of the successive vertical distances sensed by such first means as the grade reference device travels over the subgrade. Third means on the paver senses the vertical distance between successive points along said predetermined path on the subgrade and a point on the screed. Fourth means continuously generate second intelligence representative of the successive vertical distances sensed by the third means as the paver travels along the aforesaid predetermined path. Fifth means compare the first and second intelligence as the latter is generated and produce grade control signals representative of the differences between the vertical distances sensed by the first and third means at the same points on the subgrade. A control mechanism for the screed is actuated by these grade control signals.

Traveling wire grade control apparatus for slipform machines

Abstract: A slipform paving machine having a vertically adjustable screed which is automatically controlled by a traveling wire apparatus to maintain grade by directly sensing the height of the screed relative to the surface to be paved. The traveling wire apparatus includes a pair of rigid bars secured to the sides of the screed to project forwardly and rearwardly from the machine, and sensing units comprising frames, taut wires, and switches are pivotally attached to each of the ends of the bars. The frames move relative to the bars any time the profile of the surface changes and the wires actuate the switches which control the height of the screed whenever relative movement between the frames and bars occurs.

Gripper clamp for screeds

Abstract: A gripper clamp is provided for facilitating the handling of screeds used in the rough levelling of concrete. The screeds are usually two by fours or two by sixes and are held by workmen at opposite ends. The handling of such screeds is simplified by the use of a gripping tool including a first handle having right angularly extending jaws to engage one side of the screed and a relatively movable handle pivotal relative to the first and having a jaw end engageable with the side of the screed engaged by the first-named jaws.

Slope control for paving machines

Abstract: Apparatus for sensing twisting of the screed of a paver including a pair of arms having their outer ends rigidly supported from the screed extending toward one another with their inner ends free. A gravity-type slope sensor is mounted on the inner ends of the arms to increase the sensitivity of the sensor to twisting of the screed.

Method of and apparatus for producing supporting layers or road surfaces

Abstract: 1280309 Road surfacing apparatus; moulding kerbs, &c FRUTIGER SOHNE AG 3 Oct 1969 48770/69 Headings E1G and E1S Machinery for shaping the edge of a road layer made from a bituminous mix into a kerb, gutter (as shown), shoulder, &c., comprises a leading vibratory screed box 1 with a shaped bottom wear plate 8 and an adjustable side plate 13, which box is hinged to a conventional finisher 4 and is flexibly connected to a trailing vibratory screed box 2 with a shaped bottom wear plate 17. The angle between the forming surfaces of the finisher and the screed boxes can be adjusted by a turnbuckle 73, and the side plates 13 and 21 (on the trailing screed) can be adjusted by levers 122 and 202. The mix is distributed by a screw 11 which extends laterally beyond the finisher, and passes under a front wall 10 of the screed box I, the inclination of the wall being variable. Either or both screed boxes can be heated (as at 22', 22), and the vibrators 9, 19, 55 can be mechanical or electrical.

Improvements in or relating to the installation of screwpumps

Abstract: 1277693 Archimedean screw pumps SIMONHARTLEY Ltd 11 Jan 1971 [31 Jan 1970] 4777/70 Heading F1C In a method of screeding the trough of an Archimedean screw pump, a screeding strip 20 of plastics material is clipped on to the outer edge of one of the screw blades 23, the strip being slotted at 22 for this purpose, and the screw is rotated so that a portion 24 of the strip trails behind the blade to screed the trough, the strip being subsequently removed The strip may be extruded from nylon, polypropylene or PVC It is stated to be known to temporarily tack-weld a steel screeding strip to the outer edge of the blade

Thick-lift flexible paving

Abstract: PAVING ASPHALT IN A LIFT THICKER THAN CURRENT SPECIFICATIONS ALLOW WAS INVESTIGATED ON A CONTRACT WHERE A BASE-COURSE LAYER 6-IN. THICK WHEN COMPACTED WAS PUT DOWN IN ONE LIFT. A 400-FT. CONTROL SECTION WHERE THE MATERIAL WAS PLACED IN TWO 3-IN. LIFTS WAS INCLUDED FOR CONTROL PURPOSES. THE RESULTS SHOWED THAT BOTH TEMPERATURE PATTERNS AND IN-PLACE DENSITIES DOWN THROUGH THE MATERIAL WERE SIMILAR FOR BOTH PROCEDURES. IT IS THEREFORE RECOMMENDED THAT THIS METHOD BE ALLOWED ON FUTURE PAVING CONTRACTS IN NEW YORK WITH THE FOLLOWING PROVISIONS: 1) A FASTER FEED-BELT SPEED IS NEEDED IN THE PAVER, 2) LARGE, "AIR-ON-THE-RUN" PNEUMATIC ROLLERS SHOULD BE USED FOR BREAKDOWN 3) PROPER SCREED EXTENSIONS ARE REQUIRED TO CONTROL SPREADING, AND 4) AN EFFICIENT MATERIALS-HAULING SCHEDULE MUST BE ESTABLISHED BEFORE PAVING BEGINS. /FHWA/