Abstract: Methods of and apparatus for controlling a startup process of a wire insulating line until a desired outside diameter of an insulated wire is obtained. A startup control apparatus according to the invention comprises an extruder for supplying an insulating material around a core conductor, a take-up device for taking up the insulated wire, a diameter measuring device for measuring an outside diameter of the insulated wire and a processor for monitoring and controlling the line startup process. In a method of controlling the startup process of the wire insulating line, the processor calculates a target speed ratio r between the extruder and take-up device, performs a first correction in which a demanded take-up speed CA' is increased by a predetermined increment .DELTA.CA if a measured wire diameter D is equal to or greater than a target wire diameter D.sub.0, followed by a second correction in which a demanded extruder speed EX' is increased by a predetermined increment .DELTA.

Abstract: An improved apparatus providing for uniformity of web thickness is disclosed. In one aspect, the apparatus includes a plurality of gap-controlling, thermal energy sources, and in heat-exchange communication with the thermal energy sources, an assembly for compensating for temperature variation proximate to the thermal energy sources and across the apparatus width. The thermal compensating assembly includes a heat exchange jacket, and in combination therewith, a heat-exchanging, working fluid that undergoes a phase change in performing its heat exchange function.

Abstract: A method of rapid prototyping through controlled layerwise deposition and extraction involving the precision control of material subtractive or removal processes in conjunction with material additive processes wherein each layer is formed by selectively depositing and removing portions of the layers in accordance with corresponding software slices of a computer model of the prototype part, and with complementary support material included in the layers and ultimately removed when the complete part has been fabricated.

Abstract: In prior art processes of this kind the actual thickness of the extrudate is measured, compared with a reference thickness and the setting regions of an extrusion plant are controlled dependent upon the degree of difference. In order nevertheless to improve the quality of the extrudate in relation to the desired reference thickness, according to the invention the evolution strategy process is used. An increase in the convergence rate can also be attained by taking into account strategy parameters which can be deterministically or stochastically changed, whereby mixing including fixedly settable strategy parameters is also possible. In particular, knowledge of the process can be involved as qualitative process partial knowledge.

Abstract: Webs are provided with edge knurls whose effective height varies along the length of the web in a predetermined manner.

Abstract: The invention relates to an extrusion installation for elongate products, more particularly plastics tubes, having an extruder 1, followed by a water-cooled calibration sleeve 8 which can be acted upon by negative pressure and a wall thickness measuring device having an ultrasonic sensor 13. The characterizing feature of the invention is that the calibration sleeve 8 is preceded by a retaining device 10 by which the at least single ultrasonic sensor 13 is borne fixed or rotatable concentrically in relation to the elongate product with a predeterminable distance between its measuring head and the external surface of the elongate product 23, and the retaining device 10 has a releasable attachment sleeve 12 whose diameter so corresponds to the inlet side internal diameter of the calibration sleeve 8 that the attachment sleeve 12 performs a precalibration.

Abstract: The invention relates to a control device for the mechanical or thermal adjustment of the nozzle (1) of an extruder for elongate products (2). In order to eliminate components for wall thickness fluctuations in the longitudinal direction of the elongate product (2) when determining the wall thickness of the elongate product (2) over its width or its periphery, a stationary ultrasonic measuring head (3) is provided in addition to a rotating or reversing ultrasonic measuring head (4). The measured values of the two measuring heads (3, 4) are so linked to one another in an evaluating unit (5) that it is possible to derive therefrom for the controller a correcting variable which leads to an adjustment of the nozzle (1) only if the wall thickness deviations discovered are due to an adjustment error at the nozzle (1).

Abstract: A device for feeding dough is provided which has a hopper for receiving dough and directing the dough downwardly to a housing which contains a first rotatable member for engaging and urging the dough downwardly toward a pair of opposed second rotatable members. The second rotatable members have a gap therebetween to receive the dough therethrough and they rotate in opposite directions to urge the dough downwardly therebetween. Both the first and second rotatable members have a surface configuration which enhances engagement between the rollers and the dough. An orifice is provided in the housing below the second rotatable members for receiving the dough from the second rotatable rollers. The dough thus leaves the housing in the form of a continuous cylinder having a diameter of the same size as the orifice.

Abstract: A film thickness controller capable of obtaining the rapidity of predetermined thickness control always even if the operation conditions are changed is disclosed.

Abstract: In order to make the thickness and strength values uniform in an extruded foil tubing made of high density polyethylene (HDPE), in the form of a long neck, an air nozzle ring is provided at the level of the end of the long neck in addition to an outer blow ring surrounding the ring nozzle of the blow head. The rate of air flow through the nozzles of the air nozzle ring is controlled dependent on a rotating measuring device for measuring the thickness of the foil which is located above the expansion portion of the foil tubing. The cooling effect of the outer blow ring is preferably twenty times greater than that of the air nozzle ring. To stabilize the foil bubble, an inner pin is provided at the level of the end of the long neck.

Abstract: An apparatus for sensing incomplete molding of an automold system in process for molding semiconductor packages.

Abstract: Upon setting various molding conditions relating to new molding, one or more than two of pseudo-correlation data Q1, Q2, Q3, Q4, Q5 . . . which are secondary physical values (a fluid pressure, a hold pressure, a pressure coefficient and the like) previously set in accordance with primary physical values (a thickness, a fluid length and the like) relating to a virtual molded article, and upon setting of the molding conditions, the molding conditions are computed from primary physical values relating to molding of an actual molded article in accordance with the correlation data Q1 . . . , the molding conditions including a design condition for dies or a result of analysis of operation.

Abstract: A method of making two-layer tablets or pellets in a twin rotor pressing machine, in which method during a normal manufacturing period powdery or particulate material is fed into die bores of a die rotor so as to form first layers, said first layers are compressed in a first step by plungers synchronously rotating with the die rotor so as to form first layer pressed articles, the two layers within the die bores are compressed in a second step by said plungers so as to obtain two-layer tablets or pellets, and said two-layer tablets or pellets are removed at a main discharge station, and in which method during an inspection period first layer pressed articles removed at an intermediate discharge station or two-layer tablets or pellets removed at said main discharge station are fed to an inspection station, characterized in that during the inspection period said first layers are compressed more than in said first step during the normal manufacturing period before samples thereof are withdrawn at said intermediat

Abstract: An extruding device for extruding plastic tubing includes an extruder with an outlet and a cooling device connected to the outlet of the extruder. The cooling device has a water-filled chamber and a vacuum tank that is directly connected downstream to the water-filled chamber such that a sealed passage for the plastic tubing between the water-filled chamber and the vacuum tank is provided. The water-filled chamber has a water-filled cooling part and a water-filled measuring part. A water- and vacuum-conveying connection is provided between the measuring part and the vacuum tank. A calibrating sleeve with an inner wall surface is connected within the cooling part and is completely immersed in water for cooling purposes. The calibrating sleeve pulls the extruded plastic tubing against its inner wall surface. A measuring device for measuring the wall thickness of the plastic tubing is connected with the measuring part.

Abstract: A calender for producing packing sheets, in particular packing sheets reinforced with synthetic fiber, has a large diameter heated cylinder, on which a packing sheet is formed and vulcanized, rotatably supported by spaced calender stands and driven by a direct current motor. An unheated cylinder of smaller diameter also driven by a direct current motor, is supported by the calender stands for rotation and for movement toward and away from the heated cylinder and is hydraulically pressed toward the heated cylinder as a pressure roller. The circumferential speed of each of the cylinders is sensed by a pick-up activated by uniformly spaced marks on the circumference of the cylinder and the thickness of the packing sheet on the heated cylinder is sensed by sensing the position of the shaft of the pressure roller.

Abstract: A device for controlling the thickness of a sheet in calendering includes a thickness measuring unit for measuring the thickness of the sheet immediately after it has been formed by a pair of calender rolls, and a roll adjusting unit for moving at least one of the pair of calender rolls toward and away from the other calender roll. The device further includes a detection unit for detecting change in distance between the axes of the pair of calender rolls, and a control device for comparing the measured thickness of the sheet with a target thickness to obtain a difference therebetween. The control device then calculates a gap adjusting value on the basis of the difference, and compares the change in distance between the axes of the rolls detected by the detection unit with the calculated gap adjusting value. When these values become equal, the control device stops the movement of the one calender roll to make the thickness of the sheet equal to the target thickness.

Abstract: An apparatus for mating a finished ophthalmic lens includes a pre-manufactured lens or lens wafer as a part of a mold for making the finished lens. A polymerizable lens material is injected between the lens or lens wafer and a conventional mold member and a trio of indexers are used to rotate the conventional mold member relative to the lens wafer, to adjust the spatial relationship between the conventional mold member and the lens or lens wafer, and to control the angular relation between them. The assembly is subjected to irradiation and the radiation cures the polymerizable lens material and fuses it to the lens wafer so that the lens or lens wafer becomes an integral part of the finished lens. The apparatus produces a finished lens in less than one hour.

Abstract: Apparatus and method are described for controlling thickness of plastic films produced by the blown film process. The apparatus is an air cooling ring modified to include devices for locally modifying the temperature of the air discharged from the air ring onto the blown bubble. Local variations in the temperature of the cooling air applied to the surface of the bubble result in variations in the bubble cooling rate and viscosity, with consequent variations in thinning during transverse bubble expansion. The method includes controlling the location and extent of local temperature variation applied to the bubble in response to comparison of measured film thickness with a desired film thickness.

Abstract: A system for monitoring and controlling the output of extruder apparatus for producing a blown synthetic resin film. An infrared imaging system provides for measuring the temperature of the blown film simultaneously at multiple points on the film between the blowing head and the frost line of the film bubble. The multi-dimensional temperature profile measured by an infrared camera is processed in a computer controller in order to provide control inputs to various components of the extruder apparatus. The extruder apparatus is controlled so as to maintain a desired temperature profile substantially at that which is known to provide a high quality end product.

Abstract: An extruder head has an inner die member (5) housed in a supporting body (2) and provided with a central duct (6) continuously passed through by a semifinished product (7). An outer die member (9) exhibits a shaped housing (10) defining, in cooperation with the inner die member (5), an outflow port (11) for the mixture to be applied to the semifinished product (7). The shaped housing (10) is defined in a centering element (12) rotatably housed, according to an oblique and incident axis relative to the axis of the central duct (6), within an intermediate collar (13) rotating in the supporting body (2) in coaxial relation with the central duct itself. By rotating the centering element (12), the outflow port (11) moves from a centered position to a maximum-eccentricity position with respect to the central duct (6). The rotation of the intermediate collar (13) modifies the orientation of the common plane containing the axes of the outflow port (11) and central duct (6).

Abstract: A cast film die used to integrally form closure elements on a film of varying thickness has a removable lower die lip with grooves in the shape of the closure elements and a choker bar located in the manifold of the die to control the amount of extrudate that flows to the grooves.

Abstract: A method and apparatus for stretching dough is provided, by which bread dough or confectionery dough is continuously and smoothly stretched by linearly reciprocating a roller over the surface of the part of the dough that is continuously conveyed by a downstream conveyor of a pair of conveyors, one a downstream conveyor and other an upstream conveyor, while the roller rolls on the dough, without destroying the gluten tissue of the dough, and while determining the conveying speed of the upstream conveyor in response to the change of the thickness of the dough to be stretched, thereby obtaining, in one operation, a desired and uniform dough thickness from the continuously supplied dough material.

Abstract: The invention relates to a process for the film correction of the thickness profile of a blown portion in the production of bubble film in which the flow of cooling air is varied in individual peripheral regions of the film bubble. According to the invention, at least part of the cooling air is taken via an exit slot which is divided into individual separately fed segments in the peripheral direction of the film bubble and the supply of additional cooling air via the exit slot is, for example, controlled per segment using radial blowers. In this manner it is possible accurately to regulate the cooling action and thus the film thickness in the individual peripheral regions of the film bubble.

Abstract: A plastic material, controlled at a desired temperature, is fed on an upstream side of a gap between a pair of rotating forming rolls arrayed almost in parallel and controlled at a desired temperature from a device for feeding the plastic material. The plastic material is pressed and formed into a sheet by the forming rolls therebetween while forming a bank or an accumulation of the plastic material on an upstream side of the gap of the forming rolls and is carried out on a downstream side of the gap. The bank quantity monitoring is performed by measuring a temperature of the sheet carried out through the gap of the forming rolls and estimating the quantity of the bank in accordance with measured temperature information. The sheet formation is performed by measuring a temperature of the sheet carried out through the gap of the forming rolls and controlling various forming conditions according to a measured temperature information.

Abstract: An improved apparatus providing for uniformity of web thickness. In one aspect, the apparatus includes a plurality of gap-controlling, thermal energy sources, and in heat-exchange communication with the thermal energy sources, an assembly for compensating for temperature variation proximate to the thermal energy sources and across the apparatus width. The thermal compensating assembly includes a heat exchange jacket, and in combination therewith, a heat-exchanging, working fluid that undergoes a phase change in performing its heat exchange function.In another aspect of the invention, the apparatus includes an element disposed along an exit slot-forming lip, that reduces localized thermal gradients along the lip. This element functions as a heat sink and a heat source proximate to the lip gap, and likewise includes a heat-exchanging, working fluid that undergoes a phase change.

Abstract: An extrusion die for extruding a thermoplastified synthetic resin, e.g. for a foil-blowing head or a wide-slit nozzle can have its adjustable lip positioned to vary the thickness of the extruded strand by a driver acting on a rod engaging that lip and driven by a step-down transmission from a servomotor which may be a stepping motor.

Abstract: A calendar for the production of packing sheets has a heated cylinder of large diameter on which a packing sheet is progressively built-up of layers of rubber-fiber mixture during many revolutions and the cylinder and an unheated counter pressure cylinder of smaller diameter mounted in slidable bearings for rotation and for movement toward and away from the heated cylinder. As the packing sheet is progressively built-up on the heated cylinder, its thickness is continuously measured by feeler rollers pressed lightly against the surface of the packing sheet and associated inductive sensors. In a comparison circuit, the values of thickness-indicating signals received from the sensors are compared with the sum of an initial zero value recorded before rubber-fiber mixture is applied to the circumference of the heated cylinder, and a predetermined desired value. When the value of the thickness indicating signal equals the sum of the zero value and the desired value, the calender is stopped.

Abstract: A meltblowing system with a modular die design and on-line monitoring of web properties is described. The modular die consists of individually fed side-by-side meltblowing units. Automated control of the polymer feed rates to the units have been shown to produce a web with excellent uniformity of basis weight. The die also features a valve assembly for minimizing polymer afterflow and die tip plugging.

Abstract: A device for smoothing out the thickness of a sheet of thermoplastic material which includes a sheet die and a heating device which is integrated with the upper die lip of the sheet die. The heating device includes a hollow box filled with a liquid and a bar which projects laterally beyond the endfaces of the hollow box. The inlet and outlet openings of the bar in the hollow box are sealed. Arranged on the underside of the bar are small hot plates which are electrically heated. The liquid in the hollow box serves as a heat transfer medium and typically is an oil having a boiling point higher than 280.degree. C.

Abstract: A foil-blowing head has a nozzle lip which is substantially cylindrical and of an axial length of at least several centimeters and a radial thickness of at least several millimeters. High-force servoeffectors which can be provided with stepping servomotors, speed-reduction transmissions and eccentric drivers, can act upon radial rods to deform the lip and adjust the gap width and the thickness of the foil which is produced to provide continuous thickness correction during foil blowing.

Abstract: An apparatus for making a noodle base having a construction wherein raw materials of a noodle base are kneaded and stretched in an arbitrary direction by a screw conveyor and extruded as a noodle base having a thick sheet-like form. The extrusion die has a split die structure consisting of a die main body having the upper surface thereof open and a cover body supported rotatably at the base end portion of the die main body and covering the open portion of the die main body, and the cover body is provided with a cover body pushing member for pushing the tip portion of the cover body lest the cover body float up, and for adjusting the height of an extrusion port of the noodle base by adjusting the height of the tip portion of the cover body relative to the die main body.

Abstract: A method of controlling the weight of cut pieces of dough is disclosed. The method includes determining a target mass loading of a strip of dough, measuring the actual mass loading, comparing the actual and target mass loading values, calculating a calendar roller gap distance which compensates for the rheological properties of the dough and adjusting the gap distance of the last calendar roller pair to equalize the actual and target mass loading values.

Abstract: The present invention provides an extrusion apparatus having an improved mechanism for thermally-controlled, lip gap adjustment. The apparatus includes a flow path for a gaseous cooling medium, in which flow path a plurality of temperature-responsive, lip gap adjustment members are disposed. In contact with each such adjustment member is a heating element.

Abstract: An apparatus is disclosed for producing a continuous belt-like sheet of bread dough. The apparatus includes a dough hopper, vertical conveyors mounted on the facing side walls of the hopper, a dough outlet provided at the bottom of the hopper, and a pair of discharging rolls constituting part of the dough outlet, facing each other, and which are rotated so as to downwardly pass the bread dough passing therebetween. The width of the outlet and the peripheral speed of the discharging rolls are controllable so that a high-quality sheet of bread dough is continuously produced, while the gel structure of the dough is maintained uninjured.

Abstract: A multi-layer, multi-parison extrusion head in which nearly identical parisons are extruded from each extrusion station of the head when operated in an intermittent mode. Resin passages are provided within the extrusion head for supplying each of the resins to each extrusion station with the passages configured in a manner such that the ratio of resin volume for one resin in the passages for a given extrusion station compared to the volume of a second resin in the flow passages to the same extrusion station is the same for all extrusion stations while the volumes of resins feeding each station are not equal. As a result, a relatively simple configuration of passages is provided without requiring all of the passages to be of equal length.

Abstract: An extrusion molding method for improving the fluidity of a molding material in the die and significantly improving the productivity of the molded article of uniform thickness, and an extrusion molding apparatus adapted for smoothly carrying out the method and having an unsophisticated constructional arrangement, are disclosed.Molding is carried out while the die to which an extrusion orifice gap adjustment device is annexed is kept in resonant vibrations. The extrusion orifice gap adjustment device is annexed to a portion of the die constituting an extrusion orifice section, and molding is carried out while only the portion of the die is kept in resonant vibrations. The extrusion orifice gap adjustment device is annexed at a node of the resonant vibrations.

Abstract: A process and apparatus for controlling the thickness of film made in a blown film machine having a rotating die, wherein a variable speed motor is used to control the haul-off speed of the film from the machine, by subdividing the die rotation into angular segments, measuring the blown film thickness at a point fixed in space and across each of the angular segments, and calculating an average film thickness for an angular segment, and comparing the measured thickness against a preselected desired thickness, and increasing or decreasing the speed of the variable speed motor to change the haul-off speed to bring the measured thickness into agreement with the preselected thickness.

Abstract: Blown or flat-extruded plastic film having systematic plus or minus errors in thickness along the width of the film have a thickness profile measured and the measured profile is fed to a computer which controls the extruded film or tube from which the film is blown so that the foil thickness will be increased between regions of plus-thickness error or decreased in sense between regions of minus-thickness errors, or both alternatingly, so that the resulting coil is cylindrical with significant precision and without the need to move the blowing head or tube flattening device.

Abstract: A process for the production of a plastic foil of thermoplastic material as well as for winding this plastic foil into a coil. The produced plastic foil has systematic thickness errors with plus thickness errors and minus thickness errors. The coil is practically free of thickness errors summed during winding. In order to achieve this, the thickness-error profile of the produced plastic foil with its systematic plus thickness errors and/or minus thickness errors is measured prior to the winding of the coil. A number n of layers of the plastic foil produced with the systematic plus thickness errors and/or minus thickness errors is wound up to a coil. After that, approximately a number n of layers of the plastic foil with the inverse thickness-error profile is wound on the coil. This is periodically repeated, n layers of plastic foil with the thickness-error profile alternating with approximately n layers with inverse thickness-error profile, until in the end the adequately cylindrical coil is produced.

Abstract: A system for controlling the outer diameter of a strand, particularly of a cable or the like including a measuring device for measuring the outer diameter of the strand of plastic material emerging from the extruder. The signal of the measuring device is fed to a comparator which compares it with a reference diameter and generates a difference signal. A control unit receives the difference signal to control the rotational speed of the extruder and/or the speed by which the strand emerges from the extruder. A computing stage is connected to the control unit which generates a comparison signal modulated by the actual diameter signal and fed to the control unit.

Abstract: A method of making a coil of a plastic foil forms a flat web by extrusion through a wide slit nozzle or by film blowing and determines the thickness-error profile of the foil wound on a coil. Based upon monitoring the contour of the coil the inverse thickness-error profile is produced by control of the die gap and wound on the coil so that the coil is built-up alternatingly with the original thickness-error profile and the inverse thickness-error profile until completion of winding so that it has a sufficiently cylindrical coil contour.

Abstract: A plastic material, controlled at a desired temperature, is fed on an upstream side of a gap between a pair of rotating forming rolls arrayed almost in parallel and controlled at a desired temperature from a flat die connected to an extruding machine and having a slit outflow portion. The plastic material is pressed and formed into a sheet by the forming rolls therebetween while forming a bank or an accumulation of the plastic material on an upstream side of the gap of the forming rolls and is carried out on a downstream side of the gap. The bank quantity monitoring is performed by measuring a temperature of the sheet carried out through the gap of the forming rolls and estimating the quantity of the bank in accordance with measured temperature information. The sheet formation is performed by measuring a temperature of the sheet carried out through the gap of the forming rolls and controlling various forming conditions according to a measured temperature information.

Abstract: Apparatus for stretching dough is provided, by which bread dough or confectionery dough is continuously and smoothly stretched by linearly reciprocating a roller over the surface of the part of the dough that is continuously conveyed by a downstream conveyor of a pair of conveyors, one a downstream conveyor and other an upstream conveyor, while the roller rolls on the dough, without destroying the gluten tissue of the dough, and while determining the conveying speed of the upstream conveyor in response to the change of the thickness of the dough to be stretched, thereby obtaining, in one operation, a desired and uniform dough thickness from the continuously supplied dough material.

Abstract: The present invention provides a novel extrusion apparatus that is advantageous for converging rheologically dissimilar streams. Flow transition of a converging stream can be beneficially effected. For instance, a converging stream may be specially contoured by mere mechanical adjustment of a flow-restricting member of the apparatus.

Abstract: A feedblock is provided for producing a laminated plastic sheet with each layer of the laminated sheet being of substantially uniform thickness. The feedblock includes a plurality of lamella channels each of which is of non-rectangular cross-sectional shape. The particular non-rectangular cross-sectional shape of each lamella channel is selected to offset the tendency of the extruded plastic to thin and spread non-uniformly. Thus, the thinning and spreading of the extruded plastic will urge the plastic into a layer of substantially uniform thickness.

Abstract: A calender for producing packing sheets has a heated cylinder of large diameter and an unheated pressure cylinder of smaller diameter which is movable toward and away from the heated cylinder to vary the width of a gap between the cylinders. A plastic mixture plasticized by a solvent is fed to the gap between the cylinders and is formed into a sheet on the heated cylinder, where it is vulcanized. Two temperature sensors on a common support are positioned to measure the temperature of the outer surface of such sheet and transmit the temperature measurement to a procesor which is programmed to control operations of the calender. A further sensor measures the thickness of the sheet on the heated cylinder and the thickness measurement is transmitted to the processor as a further parameter in control of operation of the calender.

Abstract: This invention relates to an inspection system for a container made of synthetic resin, including a first container conveying station provided with a plurality of container holders arranged around the circumference of a rotary disc with predetermined spaces; a container feeding station for feeding the containers to a container conveying passage of the first container conveying station with the interval equal to that between the adjacent holders; a first inspecting station for inspecting the existence of the heat resistant resin of the container; a second inspecting station for inspecting the wall thickness of the container; a second container conveying station provided with a container receiving end portion for receiving the container determined to be a good product by the inspections of the first and second inspecting stations and conveying the container externally of the first container conveying station; and a first container discharging station for discharging a container judged to be a faulty product by

Abstract: For filling the edge groove (26) of an insulating glass pane (1) of an arbitrarily designed outer contour with sealing compound, stored geometrical data of the outer contour of the insulating glass pane (1) are utilized for controlling the relative motion between the insulating glass pane (1) and the filling nozzle (4). The relative velocity of the relative motion between the insulating glass pane (1) and the filling nozzle (4) is varied in such a way that the desired extent of filling of the edge groove (26) remains constant even in case of a change in the depth of the edge groove and/or in case of fluctuating feeding rate of a sealing compound. Furthermore, the relative speed between the filling nozzle (4) and the insulating glass pane (1) is selected to be higher in the zone of linear or less strongly curved sections (6) of the edge groove (26) than in the zone of more strongly curved sections (5).

Abstract: For measuring thickness of films of synthetic thermoplastic which have been solidified but not yet fully cooled after extrusion, a capacitive measuring head is moved into contact with the film and during a measuring cycle is moved over the surface of the film in the area in which the measurement is to be effected. The measuring head is disengaged from the film after each measuring cycle. To ensure that the measurement will not be affected by a temperature rise of the measuring head during a measuring cycle, the measuring head is moved into contact with the film before the measuring cycle begins and the measuring cycle is not initiated until a time has elapsed in which the measuring head has assumed a temperature which remains substantially constant throughout the measuring cycle.

Abstract: A concrete leveling machine is provided which propels itself over the surface of laid concrete and by use of rotating augers or oscillating stabilizers and a temper, levels and finishes the surface to a prescribed level and condition. A laser reference beam transmitted over the surface is detected by detectors attached to the leveling section of the machine and deviation of the level of the detectors from a reference level is adjusted so that the leveling section is also brought to a level required to produce the desired surface level. The machine is turned by a turntable integral with the main body which lifts the machine allowing it to turn by differential drive to its drive wheels.