Showing papers on "Screed published in 1991"

Wheeled concrete screed

Abstract: A wheeled concrete screed, comprising a strike board and blade assembly, a pair of corresponding main handle members pivotally mounted to the strike board and blade assembly, a pair of corresponding wheel assemblies affixed to and extending downwardly from the main handle members, and means to adjust the pitch of the strike board and blade assembly independent of changes in elevation of the strike board and blade assembly.

Adjustable screed and adjustment means therefor

Abstract: A power screed (2) for smoothing freshly poured concrete (36) and a method of operating the screed is described. The screed has adjustable vertical support means (28) to account for uneveness in the supporting surface (34). The support means are located near each side of the screed and are controlled by hydraulic motors (38). The screed can be adjusted manually and/or automatically through the use of an external laser source (44). When concrete is poured, it is roughly smoothed by rakes or similar tools. The screed is then advanced over the concrete with the lowest level of the screed determining the level of the surface of the concrete. Where the supporting surface upon which the concrete is poured is uneven, the screed can be raised or lowered to ensure that the upper surface of the concrete is level. The support means are each composed of two screw jacks (30) mounted on a ski (32). As the screed advances through the concrete, the support means leaves a track in the concrete which must be smoothed and filled manually. Presently, the level of a screed is controlled by bulkheads located at either side of the screed. The bulkheads must be installed in such a manner that an upper level of th bulkheads corresponds to an upper level of the finished concrete. With the present invention, the bulkheads can be eliminated.

Controlled density paving and apparatus therefor

Abstract: Obtainment of specific asphalt paving densities during roadbed repair by preshaping hot mat top surfaces concurrent with or/and prior to compaction. Like a shaped munition, a preshaped top surface on recently laid hot asphalt mat transmits surface compacting forces in precalculated directions and carries therewith asphaltic materials so as to obtain desired finished paving densities. A conventional strike off bar is modified with base indentations which partially and wholly, according to desired specifications, grade or top dress hot asphaltic mat with desired, force-transmitting shaped planes. Adjunct apparatus is employed by way of translating and rotating plates to partially or wholly cover the indentations so as to effect various, but differing, desired shapes; such adjunct apparatus includes a unique, edge and rut compaction shoe. An improvement to the conventional vibrating screed is also employed to effect the initial asphaltic mat shape while simultaneously tamping the shape gradually into its desired and compacted final form. This conforming screed is used with the modified strike off apparatus and a roller compactor or may be used in lieu of either. Likewise, it may employ the compaction shoe device for pre-compacting edge, seam or rut portions of a roadway.

Concrete pouring and leveling devices and method of using

Abstract: Concrete pouring and leveling devices and method of using them consisting of vertically placed rigid cylindrical tubes or pipes having reusable yokes inserted at their tops to support screed pipes placed horizontally along the predetermined desired elevation of the concrete surface.

Screed rail support apparatus

Abstract: A concrete screed rail support apparatus which includes a saddle having a channel with open ends and an open top for accommodating a screed rail, and a pair of arms each connected at its proximal end portion to the saddle. Each arm extends outwardly from the saddle and connects to a leg at the distal end portion. Each leg extends toward the concrete pour surface, and the length of each leg between the pour surface and its connection to the distal end portion of the arms is adjustable. Locking mechanisms are provided to fix the position of the legs once adjusted and to lock the screed rail to the saddle. Pads can be used between the pour surface and the legs for stability and to prevent damage to vapor barriers or waterproofing membranes.

Heat passage tunnel for screed burner

Abstract: A heating device for heating a substantially planar screed plate for a paving machine comprising a plate being spaced from the screed plate, and a space being defined therebetween. A heated gas inlet feeds into a tunnel connecting to the space. At least some of the heated gas is directed from the tunnel substantially parallel to the screed plate. The tunnel is formed from a plurality of tunnel branches with a orifice attached to the end of each tunnel orifice determining the direction where the heated gas will be directed.

Screed spreader box and compaction roller

Abstract: A spreading device for applying paving material behind a towing vehicle, has a fixed or extendable frame spreader box, an adjustable screed for screeding or spreading the paving material to a desired depth of spread, an adjustable compression roller for compacting the paving material, sides on the spreader box, adjusters on the screed and the compression roller to adjust the depth of spread of the paving material, and a pressure cylinder attached between the towing vehicle and the spreader box for applying pressure downwardly on the compaction roller while lifting upwardly on the towing vehicle.

Extensible screed for compacting and finishing roadcovering with liquid binder spreading means.

Abstract: of EP0418105The screed (table) for compacting and finishing comprises a central element (11) and two lateral elements (12a, 12b) which are movable in the transverse direction relative to the central element (11). Each of the lateral parts (12a, 12b) of the compacting screed (table) carries a boom (18a, 18b) for spraying binder. The booms (18a, 18b) form a spraying assembly whose width is variable as a function of the width of the compacting screed (table). A trough (25), integral with one of the booms (18a) and arranged substantially over its entire length, makes it possible to recover the bitumen jets (22) of the boom (18a) in the overlap zone of length L between the booms (18a) and (18b).

New type of ultrathin friction course

Abstract: A new kind of ultrathin surfacing, intermediate between chip seal and very thin asphalt hot mix, has appeared recently. It basically consists of a layer of hot precoated aggregate, spread over a binder spray application. A specifically designed machine spreads both binder and coated aggregate in a single pass and smooths the course. The machine includes a receiving hopper, conveyors, binder storage tanks, a variable-width spray bar, and a light heating screed unit with extensions. It operates at high speed, currently about 20 m/min. The binder is a modified emulsified asphalt. Its application rate varies between 0.6 and 1.2 kg/sq m. The friction course itself consists of an aggregate, mostly 6 to 10 mm in size, coated with a mortar made of sand, filler, and asphalt cement. The latest content ranges from 5 to 5.5 percent. The course thickness is between 1 and 2 cm. Its application rate of total mix is between 23 and 28 kg/sq m. The resulting surfacing is homogeneous. It offers a rough macrotexture and high levels of skid resistance. It has shown some capacity of leveling existing small irregularities of the support. Its rolling noise is significantly lower than that of chip seals made with aggregate of the same size. To date, the behavior of this friction course appears to be promising, as no deterioration of any kind has been observed after 2 years, even under heavy traffic.

Adjustable screed rail

Abstract: Disclosed is an adjustable screed rail or guide comprising a top T-shaped element and an inverted lower T-shaped element which cooperate to form an adjustable elongated I-beam. The top T-shaped element and the lower T-shaped element are respectively formed of a flange element and at least one web element centrally located and perpendicular to the respective flange element. The lower T-shaped element has a second web element spaced from said at least one web element, the web element of the top T-shaped element being slidably located between the two lower web elements to adjust the height of the screed surface. The screed rail is locked in the adjusted position by bolts and wing nuts. The upper and lower flanges are provided with depending lips which serve the purpose of retaining poured cement or mortar against the screed rail, the screed rail providing reinforcement for the cement or mortar bed. The depending webs also have openings through which cement, mortar and/or reinforcing rods may be passed. The top T-shaped element is provided with a second depending web element parallel to the one centrally located web element, the bottom edge of the second web element being engageable with the top edge of one of the two lower web elements to provide a minimum-thickness gauge whereby a poured concrete or mortar bed will meet minimum code requirements for thickness.

Hand trowel for flooring - has board with smoothing edge and spacer guides

Abstract: The trowel/float board has a smoothing edge and two spaced distance elements at the edge which protrude at right angles from the board and stand parallel to one another. Each spacer (16) should be disc shaped with a circular rim (18) and slot (20) terminating in the disc centre. The board (12) and edge (16) reach into each disc to the end of the slot. USE/ADVANTAGE - Flooring, screed materials, e.g. expensive plastics coverings. Covering is smoothed and spread in quick time despite board angle so the floor sets level and smooth.

Improvements in and relating to paving machines

Abstract: of EP0493889In a paving machine an extension screed plate (8) is carried on an assembly supported on a guide tube (6), the weight of the assembly when clear of the ground is carried by pressure pads (17, 18), bearing on a pair of rails (4, 5) carried by the main screed plate (7) assembly and immediately adjacent to the guide tube (6). A pressure pad (19) on the main screed plate (7) assembly bears on a rail (12) on the extension screed plate assembly and supports the assembly against the reaction of the ground forces in operation.

Pavement thickness control apparatus

Abstract: A measuring arm (12) is mounted to a frame body (5a) for supporting a screed (5). Height sensors (13 and 14) are mounted to the measuring arm (12), and another height sensor (19) is mounted to an arm (18) of the screed (5). Spaces between the tail end of the screed (5) and the height sensor (19), between the height sensor (19) and the height sensor (14) and between the height sensor (14) and the height sensor (13) are set constant. A traveling-distance-counting distance sensor is provided on the traveling vehicle. A height Ho of the both height sensors (13 and 14) relative to the screed (5) is kept constant at a given value irrespective of how much the screed (5) and the measuring arm (12) are inclined. The sensors (13, 14, and 17) are connected to an arithmetic unit (30), and the height sensor (19) to an arithmetic unit (40), respectively. The arithmetic unit (30) calculates a pavement thickness in response to signals output from the height sensors (13 and 14), and the arithmetic unit (40) detects unevenness of an unpaved surface in response to signals output from the height sensor (19), and controls the screed (5) so as to correct the unevenness. Operating conditions are set in the control device (30) by use of a recording medium such as an IC card.

Method of controlling pavement thickness in motor grader and method of setting conditions for automatic control

Abstract: A measuring arm (12) is mounted to a frame body (5a) for supporting a screed (5). Height sensors (13 and 14) are mounted to the measuring arm (12), and another height sensor (19) is mounted to an arm (18) of the screed (5). Spaces between the tail end of the screed (5) and the height sensor (19), between the height sensor (19) and the height sensor (14) and between the height sensor (14) and the height sensor (13) are set constant. A traveling-distance-counting distance sensor is provided on the traveling vehicle. A height Ho of the both height sensors (13 and 14) relative to the screed (5) is kept constant at a given value irrespective of how much the screed (5) and the measuring arm (12) are inclined. The sensors (13, 14, and 17) are connected to an arithmetic unit (30), and the height sensor (19) to an arithmetic unit (40), respectively. The arithmetic unit (30) calculates a pavement thickness in response to signals output from the height sensors (13 and 14), and the arithmetic unit (40) detects unevenness of an unpaved surface in response to signals output from the height sensor (19), and controls the screed (5) so as to correct the unevenness. Operating conditions are set in the control device (30) by use of a recording medium such as an IC card.

Control device of screed work angle for civil engineering machine

Abstract: PURPOSE:To always make the surface of a pavement even by providing detecting sensors for detecting a vertical movement in a screed and a machine body respectively having an expansion mechanism, and driving the expansion mechanisms with this detecting signal to control the work angle accurately CONSTITUTION:A control device consists of a machine body 1, a screed 7, a leveling arm 9, a sub arm 11, a first and a second expansion mechanisms expansible in the vertical direction, a sensor 39 for detecting a vertical movement of the machine body 1, a sensor 45 for detecting a vertical movement of the screed 7, and a driving means A vertical movement of the screed 7 is detected by the sensor 45 to expand and shrink the second expansion mechanism 19 with this signal, and the leveling arm 9 is moved vertically to obtain the accurate work angle of the screed 7 A vertical movement of the machine body 1 is detected by the first machine body detecting sensor 39 to expand and shrink the first and the second expansion mechanisms 17, 19 simultaneously The work angle can be thereby controlled accurately to make the surface of a pavement even

Introducing new technology to the jobsite

Abstract: The evaluation of the costs and benefits of innovative technology involves an examination of its longterm effects on the owner, the corporate image, and the employees. The article describes the use of the laser screed as an example of a new technology that must be evaluated by the aforegoing perspectives. The personnel factor is discussed, as well as limitations of the use of laser to jobs more than 50,000 sq ft. The case is described of the use of the laser screed at the Frick Floor Systems, Incorporated in South Brunswick, New Jersey.

Device for detecting thickness of pavement

Abstract: PURPOSE:To highly accurately detect the thickness of a pavement without modifying a vehicle by arranging a rotary laser projector capable of projecting a laser beam in the horizontal direction in the vicinity of a road to be paved, and fixing laser beam receivers on two front and rear positions of the side of a screed arm. CONSTITUTION:A laser level 1L rotating in parallel with ground surface is set up by rotating the head of the rotary laser projector 1 and detected by two laser beam photodetectors 3a, 3b fixed to the two front and rear positions of the side of the screed arm 2. Then upper and lower deviations from the level 1L to be a reference face are found out to detect the position of a distance detector 4 positioned between the front and rear photodetectors 3a, 3b and find out the position of unpaved ground surface from the reference face. Then, the traveling distance of an asphalt finisher is detected by a traveling distance meter 8 arranged on the lower part of the vehicle 7.

Japan's automated workforce

Abstract: The findings of an ACI-sponsored study mission to Japan are reported. The Japanese have found that greater automation and robotic technology at the building site can boost productivity, improve safety and working conditions, and help compensate for the smaller construction work force. Assembly line techniques and robotic systems once found only in factories have moved onto the construction site. In Japan, machines that can replace workers are called construction robots. These machines operate on automation levels that range from those that repeat a fixed sequence to those that determine their own action based on recognizing their surrounding environment. Some are operated by remote control. Experimental and practical construction robots have been used to build tunnels, maintain buildings, and demolish structures. The article describes equipment to screed, finish and grind concrete floors, and fabricate reinforcement. Machines for placing concrete, consolidating concrete, cutting concrete, painting exterior walls, and constructing tunnels and tunnel linings are described.

Method and machine for paving road with rolled concrete

Abstract: PURPOSE:To improve the adhesion of upper and lower pavement by uniformly laying and compacting a paving material of a lower layer portion, and further laying and compacting thereon a paving material of a upper layer portion after scarifying the compacted surface. CONSTITUTION:After a paving material is dropped onto a road foundation F through a feeder from a hopper 2 of a paving machine B to be spread by a screw spreader 3, a lower layer portion h1 is formed by uniformly laying and compacting the paving material with a screed 4. Next, the compacted surface of the lower layer portion h1 is scarified by a scarifier provided in front of the spreader 3. Then, a paving material of an upper layer portion h2 is laid and compacted on the compacted surface of the lower layer portion h1 to form a paving layer H. Further, after secondarily rolling the upper surface of the paving material H with a vibrating roller C, the pavement is finished with a finishing roller D.

Wood concrete floor screed-forming mixt. - contains hydraulic binder, wood flakes, rigid foam and ceramic chips

Abstract: A mixt. for prodn. of wood concrete screeds consists of a hydraulic binder and an aggregate mix of dedusted and impregnated wood flakes of pref. 4-8 mm. size, rigid foam material (e.g. styropor) in granulate or flake form, .and ceramic chips (pref. of brick, gas concrete, perlite, pumice, expanded clay or slag). ADVANTAGE - The mixt. exhibits reduced tendency for bubble and crack formation and has high wear resistance.

Method and arrangement for forming a screed track

Abstract: The invention concerns a method for forming a screed track for a vibro-frame or equivalent which is used in particular for direct smoothing of single-layer floors, with vertically adjustable support feet being placed at a distance from each other along the site of a joint which is to be formed, and these support feet being intended to support a screed bar According to the invention, each of the support feet is formed by a combination of a foot plate, a guide tube of adaptable length which extends upwards therefrom and can be released therefrom, and a slide tube which can be mounted on the guide tube and displaced and locked thereon, with a support for the screed bar, which support has an adaptable height, and the guide tube is chosen with different lengths and the slide tube with different screed bar supports as a function of the thickness of the floor which is to be cast, after which the screed bar is placed on the supports of the support feet and is adjusted vertically by releasing the lock of the slide tube, displacing the slide tube along the guide tube and once again locking the slide tube in position The invention also concerns an arrangement for carrying out this method

Poured concrete slab designed to form a raised floor above the support screed

Abstract: It comprises a solid part (1) extended on its lower face by five truncated feet, of which one central foot (21) and four peripheral feet (22) are positioned at a short distance from each of the corners.

Solar collector for heating heat conducting liq. - consists of pipework system laid in black screen containing metal fragments

Abstract: The solar collector for heating a heat conducting liquid by sun rays and ambient air consists of a heat conducting layer and a network of pipes. The pipes (3) are laid in a screed (5) containing metal fragements (8) and are externally electrically insulated. The screed (5) is mixed with a black colour dye and has a roughened upper surface (6). The pipes (3) are oval and are laid with the flattened side to the bottom (4) of the screed (5). An additional absorbent layer (7) is laid over the upper surface (6) of the screed (5), or alternatively the screed (5) may be laid on an insulation layer. A transparent cover (9) is placed at a distance over the screed (5). USE/ADVANTAGE - An improved solar collector simply constructed maintains its efficiency through the screed.

Construction of buildings using lightweight, heat-insulating and load-bearing building blocks

Abstract: The invention consists in using a construction system by means of which it is possible to secure a building to its support, shown diagrammatically in Figure 1 A securing pin 2 is incorporated in the support of the building 1 (concrete screed or the like), the building blocks are lined 3 and are positioned in a staggered arrangement, as for any other construction, but each row is allocated a metal rod 4 which is threaded at each end, and a threaded sleeve 5 with which the following rod can be screwed This assembly is locked at the top of the wall on the wall plate 6, preferably made of wood in order to maintain the heat-insulating characteristics of the assembly The number and the spacing of the securing elements described hereinabove depends on the constructed surface area, the local climatic conditions, and the openings made in the wall in question

Movement joint for flooring

Abstract: An intermediate movement joint 10 has a pair of substantially rigid brass plates 12a and 12b into which there are formed recesses 14 Sandwiched between the two parallel plates 12a and 12b is a resiliently deformable material, usually neoprene, which material is exposed at the edges of the intermediate movement joint and at the recesses 14 The plates can be stuck into position in a groove cut into a sand/cement screed by gluing with an epoxy resin The invention also provides a method of laying a tiled floor which method incorporates sliding or tapping an intermediate movement joint as described into position on a cement/sand screed