Slip form paver

Abstract

A slipform paver includes a slipform mold having a mold width extending transverse to a paving direction. At least one leveling beam is supported behind the slipform mould for engaging an upper surface of the formed unhardened concrete structure to level the upper surface, the at least one leveling beam being configured to oscillate transversely to the paving direction. At least one forward speed sensor is configured to provide a forward speed signal corresponding to a forward speed of the slipform paver in the paving direction. The controller is configured to receive the forward speed signal and generate a command signal to control the lateral oscillation frequencies of the at least one leveling beam such that a constant relationship is maintained between the forward speed lateral oscillation frequencies.

Description

Technical Field

[0001] The present disclosure relates to a slipform paver for providing a more consistent surface finish on a formed concrete structure. Background Art

[0002] During the slipform paving process of a concrete structure, one phenomenon encountered when using a screed beam behind the slipform mold is that the vibration of the screed beam on the upper surface of the newly formed concrete structure will form patterns in the upper surface. The structure of these patterns depends on the forward speed of the paver and the vibration frequency of the screed beam. In prior art pavers, the vibration frequencies of the transverse screed beam and / or the longitudinal screed beam are manually set, and thus as the forward speed of the paver changes, the patterns formed on the upper surface also change. These varying patterns result in inconsistent surface finishes.

[0003] These and other problems are solved by the present disclosure. Summary of the Invention

[0004] In one embodiment, a slipform paver includes a machine frame and a plurality of ground engaging wheels or tracks that support the machine frame from the ground surface. A slipform mold is supported from the machine frame for molding a large amount of concrete (or concrete mass) into a formed but unhardened concrete structure as the paver moves forward in the paving direction, the slipform mold having a mold width extending transversely to the paving direction. At least one screed beam is supported behind the slipform mold for engaging the upper surface of the formed but unhardened concrete structure to level the upper surface, at least one screed beam being configured to vibrate transversely to the paving direction. At least one forward speed sensor is configured to provide a forward speed signal corresponding to the forward speed of the slipform paver in the paving direction. A controller is configured to receive the forward speed signal and generate a control signal to control the transverse vibration frequency of at least one screed beam, thereby maintaining a constant relationship between the forward speed and the transverse vibration frequency.

[0005] At least one screed beam may include a transverse screed beam having an elongated shape with its longest dimension extending transversely across at least a majority of the mold width.

[0006] In the above embodiment, a transverse vibration frequency sensor may be configured to provide a transverse vibration frequency signal corresponding to the transverse vibration frequency of the transverse screed beam.

[0007] In the above embodiment, the slipform paver may further include a drive motor that rotatably drives an eccentric drive connected to the transverse screed beam to generate the transverse vibration of the transverse screed beam, and the transverse vibration frequency sensor may be configured to detect the rotational speed of the drive motor.

[0008] In any of the above embodiments, at least one screed beam may further include a longitudinal screed beam having an elongated shape with its longest dimension extending parallel to the paving direction.

[0009] In the above embodiments, the longitudinal screed beam may vibrate both transversely to the paving direction and parallel to the paving direction, and the controller may further be configured to generate command signals to control the longitudinal vibration frequency of the longitudinal screed beam so as to maintain a constant relationship between the forward speed and the longitudinal vibration frequency.

[0010] Any of the above embodiments may further include a transverse vibration frequency sensor and a longitudinal vibration frequency sensor. The transverse vibration frequency sensor is configured to provide a transverse vibration frequency signal corresponding to the transverse vibration frequency of the longitudinal screed beam, and the longitudinal vibration frequency sensor is configured to provide a longitudinal vibration frequency signal corresponding to the longitudinal vibration frequency of the longitudinal screed beam. The controller may further be configured to receive the transverse vibration frequency signal and the longitudinal vibration frequency signal.

[0011] In the above embodiments, the slipform paver may further include at least one winch configured to pull the carriage carrying the longitudinal screed beam across the mold width from side to side, and the transverse vibration frequency sensor may be configured to detect the rotational speed of at least one winch.

[0012] In any one of the above two embodiments, the slipform paver may further include a drive motor rotatably driving an eccentric drive connected to the longitudinal screed beam to generate longitudinal vibration of the longitudinal screed beam, and the longitudinal vibration frequency sensor may be configured to detect the rotational speed of the drive motor.

[0013] In any of the above embodiments, the slipform paver may further include a transverse oscillation frequency sensor configured to provide a transverse oscillation frequency signal corresponding to the transverse oscillation frequency of at least one screed beam.

[0014] In any of the above embodiments, the mold width of the slipform mold may be an adjustable mold width.

[0015] In another embodiment, a method of operating a slipform paver including a slipform mold may include the steps of: (a) molding a mass of concrete with the slipform mold to form a non-hardened concrete structure as the paver moves forward in the paving direction; (b) engaging the upper surface of the non-hardened concrete structure with at least one screed beam supported behind the slipform mold and oscillating the at least one screed beam transversely to the paving direction to level the upper surface; (c) monitoring the forward speed of the slipform paver with a controller; and (d) automatically controlling, with the controller, the transverse oscillation frequency of at least one screed beam such that a constant relationship is maintained between the forward speed and the transverse oscillation frequency, thereby forming a constant surface pattern on the upper surface of the non-hardened concrete structure.

[0016] In the above method, in step (b), at least one screed beam may include a transverse screed beam having an elongated shape, the longest dimension of which extends transversely across at least a majority of the die width of the slipform die.

[0017] In the above method, in step (b), at least one screed beam may further include a longitudinal screed beam having an elongated shape, the longest dimension of which extends parallel to the paving direction, and the longitudinal screed beam is located behind the transverse screed beam.

[0018] In the above method, step (b) may further include oscillating the longitudinal screed beam parallel to the paving direction while oscillating the longitudinal screed beam transversely to the paving direction, and step (d) may further include automatically controlling the longitudinal oscillation frequency of the longitudinal screed beam with a controller so as to maintain a constant relationship between the forward speed and the longitudinal oscillation frequency.

[0019] In the above first method embodiment, in step (b), at least one screed beam may include a longitudinal screed beam having an elongated shape, the longest dimension of which extends parallel to the paving direction.

[0020] In the above method, step (b) may further include oscillating the longitudinal screed beam parallel to the paving direction while oscillating the longitudinal screed beam transversely to the paving direction, and step (d) may further include automatically controlling the longitudinal oscillation frequency of the longitudinal screed beam with a controller so as to maintain a constant relationship between the forward speed and the longitudinal oscillation frequency.

[0021] Many objects, features, and advantages of the present invention will be readily apparent to those skilled in the art upon reviewing the following description in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a left elevation view of a slipform paver.

[0023] Figure 1A is along Figure 1 a schematic front elevation sectional view taken along line 1A-1A of Figure 1 and shows the front elevation of the slipform die of the slipform paver of

[0024] Figure 2 is Figure 1 a schematic left elevation view of the slipform paver of

[0025] Figure 3 is a schematic rear elevation view of the transverse screed beam.

[0026] Figure 4 is along Figure 3taken along line 4-4 of Figure 3 Left elevation sectional view of the transverse screed beam.

[0027] Figure 5 Schematic left elevation view of a part of the longitudinal screed beam and the main frame of the paver.

[0028] Figure 6 is along Figure 5 Front elevation view taken along line 6-6, showing the carriage of the longitudinal screed beam and the transverse beam on which the carriage travels.

[0029] Figure 7 Schematic diagram of the control system of the paver, which shows various sensor signal inputs and various output commands for various actuators of the paver.

[0030] Figure 8 Schematic diagram of a constant surface pattern formed by the transverse screed beam.

[0031] Figure 9 Schematic diagram of a constant surface pattern formed by the longitudinal screed beam. DETAILED DESCRIPTION

[0032] The embodiments of the present disclosure described below are not intended to be exhaustive or to limit the disclosure to the precise forms disclosed in the following detailed description. Instead, the embodiments are selected and described so that those skilled in the art can appreciate and understand the principles and practices of the present disclosure.

[0033] Now referring to the drawings and particularly to Figure 1 , a slipform paver is shown and generally designated by reference numeral 10. The machine 10 is configured to move along a paving direction 12 across a ground surface 14 for spreading, leveling, and treating concrete into a concrete structure 16 that has a generally upwardly exposed upper surface 18 and terminates in side concrete edges such as 20 that are yet to be hardened.

[0034] The slipform paver 10 includes a main frame 22 and a slipform paver mold 24, which may also be referred to as a slipform mold 24 supported from the main frame 22. A left side mold assembly 26 and a right side mold assembly 28 are connected to the slipform paver mold 24 to close the slipform paver mold 24 on the left and right sides so as to form side concrete edges such as 20 of the finished concrete structure 16.

[0035] As best seen in Figure 1A , the slipform mold 24 has a mold width 80 between the side mold assemblies 26 and 28. The mold width 80 also corresponds to the width of the concrete structure 16 formed by the mold, which is designated by Figure 3is indicated by reference numeral 81 in the drawings. The slipform mold 24 can be an adjustable-width slipform mold known in the art, but it will be understood that for any given paving operation, the mold width 80 will be adjusted to the desired width and then the mold width 80 will remain fixed during the paving operation.

[0036] The main frame 22 is supported from the ground surface by a plurality of ground-engaging units such as 30, which are crawler ground-engaging units 30 in the illustrated embodiment. Wheeled ground-engaging devices can also be used. Each ground-engaging unit 30 is connected to the main frame 22 by a lifting column such as 32 attached to a swing arm such as 34. The operator station 36 is located on the main frame 22. As used herein, the terms “left” and “right” are from the viewpoint of an operator located on the operator station 36 and facing forward in the paving direction 12. A plow or spreader device 38 is supported from the main frame 22 in front of the slipform paver mold 24. A spreading auger 39 can be used in place of the plow 38. Behind the slipform paver mold 24, a dowel bar inserter device 40 can be provided.

[0037] At least one screed beam 41 can be supported behind the slipform mold 24 for engaging the upper surface 20 of the formed but not yet hardened concrete structure to level the upper surface 20. The at least one screed beam 41 is configured to oscillate transversely to the paving direction 12. The at least one screed beam can include a transverse screed beam 42 and / or a longitudinal screed beam 44. The transverse screed beam 42 is generally referred to by those skilled in the art as the “oscillating beam” 42. The longitudinal screed beam 44 is generally referred to by those skilled in the art as the “super screed” 44.

[0038] It should be appreciated that many slipform pavers do not include a dowel bar inserter device 40. Figure 2 A further schematic view of shows a slipform paver 10 without a dowel bar inserter device 40. If the dowel bar inserter device 40 is not used, the transverse screed beam 42 and / or the longitudinal screed beam 44 can be provided behind the slipform paver mold 24.

[0039] In addition, it should be appreciated that some slipform pavers do not include a transverse screed beam 42 and thus may include only a longitudinal screed beam 44. And some slipform pavers do not include a longitudinal screed beam 44 and thus may include only a transverse screed beam 42.

[0040] Figure 2 Schematically shows a slipform paver 10 including a transverse screed beam 42 and a longitudinal screed beam 44 but not including a dowel bar inserter 40. It will be understood that the dowel bar inserter 40 can be placed between the slipform mold 24 and the transverse screed beam 42.

[0041] In Figure 2In [the figure], the lifting columns 32 are marked as 32F and 32R for the front and rear lifting columns respectively. The crawler tracks 30 are marked as 30F and 30R for the front and rear crawler tracks respectively. It will be understood that there are two front lifting columns 32F on the left and right sides of the machine 10, and the machine frame 22 is supported from the two front crawler tracks 30F. Similarly, there are two rear lifting columns 32R that support the machine frame 22 from the two rear crawler tracks 30R. In Figure 1 and Figure 2 Both, the slipform paver 10 is shown as a four-track machine that has front and rear track ground engaging units 30 on each of the left and right sides of the machine.

[0042] It will be understood that the various features disclosed herein are equally applicable to double-track pavers, such as for example the Wirtgen model SP 62i, which has a long track on each of the left and right sides of the machine frame, and a front lifting column and a rear lifting column on each side of the machine frame, and the machine frame is supported from each of the two tracks. And it will be understood that the various features disclosed herein are equally applicable to, for example, a three-track paver that has a single track on one side of the machine and two tracks on the other side.

[0043] Each of the lifting columns 32F, 32R is configured as a telescoping member and may include a hydraulic intelligent cylinder actuator, such as Figure 2 as seen in 46F and 46R. The extension and contraction of the actuators 46F and / or 46R causes the extension and contraction of the lifting columns 32F and 32R, and can raise or lower the machine frame 22 relative to the ground surface 14, and / or can adjust the longitudinal and / or lateral inclination of the machine frame 22 relative to the ground surface 14. Each hydraulic intelligent cylinder may include an integrated extension sensor to allow precise monitoring and control of the extension of the lifting column 32. Optionally, the lifting column may include a conventional hydraulic cylinder and a separate associated extension sensor. Additionally, optionally, the lifting column may not have an extension sensor at all.

[0044] Figure 1 The plow or spreader device 38 identified in [the figure] is schematically shown as a spiral spreader device 39 in Figure 2 [the figure].

[0045] Behind the spiral spreader device 39 is a height-adjustable concrete supply gate 50. The gate 50 is supported from the machine frame 22 by one or more gate actuators 52 for adjusting the height of the gate 50 relative to the machine frame 22. The gate actuator 52 can also be configured as a hydraulic intelligent cylinder with an integrated extension sensor to allow precise monitoring and control of the extension of the height of the gate 50. Optionally, the gate actuator 52 can include a conventional hydraulic cylinder and can have a separate associated extension sensor. Additionally, the gate actuator may not have an extension sensor at all.

[0046] There are a plurality of vibrators 56 between the gate 50 and the slipform mold 24, which are configured to be immersed in the concrete mass forming the slab or structure 16 to assist in compacting the concrete as the slipform mold 24 moves over the concrete mass.

[0047] During the paving process, a large amount of concrete material 16A is dumped onto the ground surface 14 in front of the paver 10. This is typically accomplished by a series of dump trucks (not shown) dumping the wet concrete they are loaded with onto the ground surface, so the supply of concrete material 16A occurs in a series of consecutive material dumps. Alternatively, a large amount of concrete can be provided by side feeders, shuttle cars, placer-spreaders, or other known concrete supply devices. The material 16A is spread transversely across the width of the paver 10 by a spreading device 38 or 39. The height of the concrete feed gate 50 is adjusted to control the amount of concrete material 16B directly in front of the slipform mold 24. With the assistance of the vibrators 56, the concrete material is consolidated and semi-liquefied, and the slipform mold 24 moves across the concrete material 16B to form a concrete slab 16. In the area 16C immediately behind the slipform mold 24, there may be some swelling in the height of the newly formed slab. A roll 16D of concrete material can be formed immediately in front of the transverse screed beam 42.

[0048] The transverse screed beam 42 is supported from the machine frame 22 behind the slipform mold 24 for engaging and oscillating transversely to the paving direction 12 on the upper surface 18 of the formed but unhardened concrete structure 16 to level the upper surface 18. Figure 3 and Figure 4 An embodiment of the transverse screed beam 42 is shown. The transverse screed beam 42 includes a first transverse screed beam member 58 and a second transverse screed beam member 60, which are pivotally connected together at a pivot pin 62. A pivot actuator 64 allows the two members 58 and 60 of the transverse screed beam 42 to pivot as shown in Figure 3 to conform to a crown (or protrusion) 66 in the upper surface 18 of the concrete structure 16. The outer end portions of the transverse screed beam 42 are slidably fixed in a first adjustable vertical beam support 68 and a second adjustable vertical beam support 70.

[0049] An eccentric drive 72 is mounted on the first beam member 58 of the transverse screed beam 42. A push rod 74 connects the eccentric drive 72 to the main frame 22. A drive motor 76 drives the eccentric drive 72 to cause the transverse screed beam 42 to swing left and right relative to the main frame 22 and the upper surface 18 of the concrete structure 16, as shown in Figure 3As seen in Figure 7 ), to level the upper surface 18. A lateral oscillation frequency sensor 82 may be associated with the drive motor 76. The lateral oscillation frequency sensor 82 may be configured to provide a lateral oscillation frequency signal 82S corresponding to the lateral oscillation frequency of the lateral leveling beam 42 (see

[0050] The slipform mold 24 may be described as having a mold width 80, which will also be equal to the width 81 of the concrete structure 16 formed by the mold 24, as Figure 3 seen in Figure 3 As also seen in Figure 3 , the lateral leveling beam 42, particularly the first and second lateral beam members 58, 60, has an elongated shape with a longest dimension 78. The longest dimension 78 may be described as laterally extending at least most of the mold width 80, and in

[0051] the embodiment, the longest dimension 78 is greater than the mold width 80 and the concrete structure width 81. Figure 5 and Figure 6 shown in Figure 5 is a schematic left elevation view of the longitudinal leveling beam 44 supported by the main frame 22 of the paver 10. Figure 6 is along Figure 5 the line 6-6 of Figure 5 a magnified front elevation view of a portion of

[0052] The longitudinal leveling beam 44 includes an elongated screed 84 having a longest dimension 86 extending parallel to the paving direction 12. The screed 84 is supported from the carriage 88 by brackets 90 and vertical legs 91. The vertical legs 91 are connected to the brackets 90 at pivot connections 98. A drive motor 92 rotatably drives an eccentric driver 94, which is connected to the vertical legs 91 by a drive link 96. When rotated by the drive motor 92, the eccentric driver 94 causes the screed 84 to oscillate longitudinally parallel to the forward direction 12.

[0053] A longitudinal oscillation frequency sensor 100 is associated with the drive motor 92 and is configured to provide a longitudinal oscillation frequency signal 100S corresponding to the longitudinal oscillation frequency of the screed 84 of the longitudinal leveling beam 44 (see Figure 7 ). The longitudinal oscillation frequency sensor 100 may be configured to detect the rotational speed of the drive motor 92.

[0054] The carriage 88 carrying the longitudinal screed 44 is arranged to move transversely across the width 81 of the concrete structure 16 on the transverse beam 102, which in turn is supported by the main frame 22 of the paver 10. The carriage 88 includes upper wheels 104 and lower wheels 106 that ride on the transverse beam 102. At one or both ends of the transverse beam 102, a winch 108 may be attached to the carriage 102 by a cable 110. The carriage 88 and the longitudinal screed 44 are moved left and right across the width 81 of the concrete structure 16 by the winch 108. Each winch 108 may be driven by a winch drive motor 112. It should be appreciated that the speed of movement of the longitudinal screed 44 transversely across the width 81 of the concrete structure 16, and correspondingly the frequency of movement left and right across the width 81 (which may be referred to as the transverse oscillation frequency of the longitudinal screed 44), is determined by the rotational speed of the winch 108. A transverse oscillation frequency sensor 114 may be associated with each winch drive motor 112 and is configured to provide a transverse oscillation frequency signal 114S corresponding to the transverse oscillation frequency of the longitudinal screed 44 left and right across the width 81 of the concrete structure 16 (see Figure 7 ). The transverse oscillation frequency sensor 114 may be configured to detect the rotational speed of its associated winch drive motor 112 and thus the rotational speed of its associated winch 108. It should be appreciated that the transverse oscillation frequency sensor 114 may also be considered to detect the transverse speed of the carriage 88 and the longitudinal screed 44 as they move across the width 81 of the concrete structure 16, but since the distance to be traveled during one left and right cycle is constant (2 times the width 81), the transverse speed will be proportional to the transverse oscillation frequency. Thus, the transverse oscillation frequency signal 114S directly corresponds to the transverse oscillation frequency and transverse speed of the longitudinal screed 44.

[0055] Further details of the mechanical structure of suitable embodiments of the transverse screed 42 and the longitudinal screed 44 can be found in U.S. Patent No. 6,471,442 assigned to the assignee of the present invention, the details of which are incorporated herein by reference.

[0056] Control System

[0057] As Figure 7 schematically shown, the machine 10 includes a control system 200 that includes a controller 202. The controller 202 may be part of the machine control system of the slipform paver 10, or it may be a separate control module. The controller 202 may be installed, for example, in a control panel located at the operator station 36. The controller 202 is configured to receive input signals from various sensors. The signals transmitted from the various sensors to the controller 202 are Figure 7 schematically indicated in by a line connecting the sensor to the controller, the line having an arrow indicating the signal flow from the sensor to the controller 202.

[0058] For example, the controller 102 may receive a forward speed signal 116S from a forward speed sensor 116 corresponding to the forward speed of the paver 10 in the paving direction 12. The forward speed sensor 116 may be, for example, a rotation sensor associated with a rotation drive motor 118 (see Figure 7 ) of one of the crawlers 30 that drives the paver 10. Any other known forward speed sensor 116 may be used. For example, the forward speed sensor 116 may operate based on a Global Navigation Satellite System (GNSS) signal received by a suitable position sensor carried by the paver 10. It should be appreciated that although there should be at least one forward speed sensor 116, there may be multiple forward speed sensors 116. For example, there may be one sensor 116 on the left crawler and one sensor 116 on the right crawler. Or each crawler may include a forward speed sensor 116, and the controller 202 may determine the average value or take the minimum value of the readings to ignore the slippage of the crawlers.

[0059] The controller 202 may receive a lateral oscillation frequency signal 82S from a lateral oscillation frequency sensor 82 associated with a drive motor 76 of an eccentric drive 72 of the transverse leveling beam 42.

[0060] The controller 202 may receive lateral oscillation frequency signals 114S from two lateral oscillation frequency sensors 114 associated with winch drive motors 112 of one or more winches 108 that drive the longitudinal leveling beam 44.

[0061] And the controller 202 may receive the longitudinal oscillation frequency signal 100S from the longitudinal oscillation frequency sensor 100 associated with the eccentric drive 94 of the longitudinal leveling beam 44.

[0062] Similarly, the controller 202 will generate command signals for controlling the operation of the various drive motors described above, and the control signals are schematically indicated by lines in the Figure 7 graphical description that connect the controller 202 to the various drive motors and related structures, and the lines have arrows indicating the flow of the command signals from the controller 202 to the corresponding drive motors. It will be understood that in order to control a hydraulic drive motor, the controller 202 may send an electrical signal to an electro / mechanical control valve (not shown) that controls the flow of hydraulic fluid into and out of the drive motor.

[0063] The controller 202 includes a processor 204, a computer-readable medium 206, a database 208, and an input / output module or control panel 210 having a display 212, or may be associated with the processor 204, the computer-readable medium 206, the database 208, and the input / output module or control panel 210 having a display 212. An input / output device 214, such as a keyboard, a joystick, or other user interface, is provided so that an operator can input instructions to the controller. It should be understood that the controller 202 described herein can be a single controller having all the functions described, or it can include multiple controllers, where the functions described are distributed among the multiple controllers.

[0064] The various operations, steps, or algorithms described in connection with the controller 202 can be embodied directly in hardware, in a computer program product 216 such as a software module executed by the processor 204, or in a combination of both. The computer program product 216 can reside in a RAM memory, a flash memory, a ROM memory, an EPROM memory, an EEPROM memory, a register, a hard disk, a removable disk, or any other form of computer-readable medium 206 known in the art. The exemplary computer-readable medium 206 can be coupled to the processor 204 such that the processor can read information from and write information to the memory / storage medium. In an alternative, the medium can be integrated into the processor. The processor and the medium can reside in an application specific integrated circuit (ASIC). The ASIC can reside in a user terminal. In an alternative, the processor and the medium can reside as discrete components in the user terminal.

[0065] As used herein, the term "processor" can refer at least to general-purpose or specific-purpose processing devices and / or logic understood by those skilled in the art, including but not limited to microprocessors, microcontrollers, state machines, etc. The processor can also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in combination with a DSP core, or any other such configuration.

[0066] In some embodiments, the data storage in the computer-readable medium 206 and / or the database 208 can include database services, cloud databases, etc. In various embodiments, the computing network can include cloud servers and, in some embodiments, can be part of a cloud application, where the various functions disclosed herein are distributed in nature among the computing network and other distributed computing devices. Any or all of the distributed computing devices can be implemented as at least one of an in-vehicle controller, a server device, a desktop computer, a laptop computer, a smart phone, or any other electronic device capable of executing instructions. The processor of the device, such as a microprocessor, can be a general-purpose hardware processor, a dedicated hardware processor, or a combination thereof.

[0067] In particular, the controller 202 can be programmed to receive a forward speed signal 116S, a lateral oscillation frequency signal 82S of the lateral screed 42, a lateral oscillation frequency signal 108S of the longitudinal screed 44, and a longitudinal oscillation frequency signal 100S of the longitudinal screed 44. And the controller 202 can be programmed to: send a command signal 118C to control the forward speed via the drive motor 118, send a command signal 76C to control the lateral oscillation frequency of the lateral screed 42 via the drive motor 76 of the eccentric drive motor 72, send a command signal 112C to control the lateral oscillation frequency of the longitudinal screed 44 via one or more winch drive motors 112, and send a command signal 92C to control the longitudinal oscillation frequency of the longitudinal screed 44 via the drive motor 92 of the eccentric drive 94. All command signals can be at least partially based on the forward speed signal and the corresponding oscillation frequency signals.

[0068] It should be appreciated that as the paver 10 advances in the paving direction 12, the oscillation of the lateral screed 42 and / or the longitudinal screed 44 on the upper surface 18 of the newly formed concrete structure 16 will form a pattern in the upper surface 18. The structure of these patterns depends on the forward speed of the paver 10 and the oscillation frequencies of the lateral screed 42 and / or the longitudinal screed 44. In prior art pavers, the oscillation frequencies of the lateral screed 42 and / or the longitudinal screed 44 are manually set, and thus as the forward speed of the paver changes, the pattern formed on the upper surface also changes. The present invention is directed to methods and apparatus for controlling the relationship between the forward speed and the oscillation frequencies of the lateral screed 42 and / or the longitudinal screed 44 so as to produce a constant pattern in the upper surface 18. This results in a more uniform finished surface, which is desirable for both aesthetic and quality control reasons.

[0069] In particular, the controller 202 can be configured via a computer program product 216 to generate command signals to control the lateral oscillation frequency of either the lateral screed 42 or the longitudinal screed 44, thereby maintaining a constant relationship between the forward speed and the lateral oscillation frequency. The result of this constant relationship is that the associated screed 42 or 44 will form a constant surface pattern on the upper surface 18 of the concrete structure 16.

[0070] In Figure 8 is schematically shown this constant relationship and the resulting constant surface pattern suitable for the lateral screed 42. In Figure 8In [reference], the pattern 220 is schematically shown in the form of a sinusoidal structure having a wavelength L1 produced by the transverse screed beam 42. The transverse screed beam 42 oscillates transversely left and right (as indicated by the double-headed arrow 222) transverse to the forward direction 12. Each point, such as 42a, on the bottom surface of the transverse members 58, 60 of the transverse screed beam 42 will form a sinusoidal pattern on the surface 18, the wavelength L1 of which is the distance traveled by the paver 10 during a single oscillation of the eccentric drive 72. It should be appreciated that the actual pattern 220 will not be a single sinusoidal line as shown in Figure 8 but will be a plurality of parallel sinusoidal surface textures that are generally sinusoidal patterns as shown in the figure.

[0071] For example, the transverse screed beam may have a transverse oscillation frequency in the range from about 0.5 to 2.0 cycles per second, and the transverse movement generated by the eccentric drive 72 is several inches. A typical paving speed range suitable for the slipform paver 10 may be from 0 to 16 feet per minute (fpm) (0 to 490 centimeters per minute (cm / min)). For example, at a transverse oscillation frequency of 1.0 cycle per second and a forward speed of 15 fpm (460 cm / min), the length L1 of the pattern 220 will be 3 inches (8 centimeters). By maintaining a constant relationship between the forward speed of the paver and the transverse oscillation frequency of the transverse screed beam 42, the distance L1 is kept constant. If the forward speed decreases (or increases), the controller 202 will detect the change in the forward speed and will decrease (or increase) the transverse oscillation frequency of the transverse screed beam 42 by correspondingly decreasing (or increasing) the rotational speed of the drive motor 76 of the eccentric drive 72 so as to keep the distance L1 at a constant value.

[0072] The constant relationship suitable for the longitudinal screed beam 44 and the resulting constant surface pattern 224 are schematically shown in Figure 9 . Figure 9 The pattern 224 of Figure 8 is more complex than the pattern of

[0073] Figure 9The pattern 224 includes a first zigzag structure 226 having a wavelength L2. The wavelength L2 is the distance that the carriage 88 of the longitudinal screed 44 moves from one edge of the concrete structure 16 to the other edge and back while the paver 10 travels in the paving direction 12. The time for the carriage to move from side to side once will depend on the speed of the winch 108 and the paving width 81 of the concrete structure. As previously mentioned, the slipform paver 10 can have a paving mold 24 with an adjustable width, but for any given paving operation, the mold width 80 and the paving width 81 will be fixed. For example, a paver such as a Wirtgen SP94 can pave surfaces between 3.5 meters (11.5 feet) and 9.5 meters (31 feet) wide. For example, a typical speed of the carriage 88 may be in the range of from 0.5 to 2.0 feet per second (15 to 60 centimeters per second). A typical paving speed range suitable for the slipform paver 10 is from 0 to 16 feet per minute (fpm) (0 to 490 centimeters per minute (cm / min)). For example, at a carriage speed of 1 foot per second (30 centimeters per second) and a paving width of 15 feet (460 centimeters), it will take 30 seconds for the carriage to move from one edge of the paving to the other edge and back. The frequency is 2 cycles per minute. At a forward speed of 15 fpm (3 inches per second) (460 centimeters per minute (8 centimeters per second)), the length L2 of the pattern 224 will be 90 inches (7.5 feet) (230 centimeters). By maintaining a constant relationship between the forward speed of the paver and the lateral oscillation frequency of the longitudinal screed 44, the distance L2 is kept constant. If the forward speed is reduced (or increased), the controller 202 will detect the change in the forward speed and will reduce (or increase) the lateral oscillation frequency of the longitudinal screed 44 by commanding a corresponding reduction (or increase) in the rotational speed of the drive motor 112 of the winch 108. This will keep the distance L2 at a constant value.

[0074] Each point on the bottom surface of the longitudinal screed 44 will form a zigzag pattern similar to 226 on the surface 18, having a wavelength of L2. It should be appreciated that the actual pattern 226 will not be a single zigzag line as shown in Figure 9 but will be a multitude of parallel zigzag surface textures generally presented in the shown zigzag pattern.

[0075] Figure 9The pattern 224 includes a second sine structure 228 superimposed on the first zigzag structure 226 and has a wavelength L3. The wavelength L3 depends on the lateral travel speed of the carriage 88 and the longitudinal oscillation frequency of the eccentric drive 94 as detected by the longitudinal oscillation frequency sensor 100. Of course, as described above, the lateral travel speed of the carriage 88 is adjusted depending on the forward speed of the paver 10, so the wavelength L3 can also be described as depending on the forward speed of the paver 10 and the oscillation frequency of the eccentric drive 94. The longitudinal screed 44 can have a longitudinal oscillation frequency in the range from about 0.5 to 2.0 cycles per second, and the longitudinal movement generated by the eccentric drive 94 is a few inches. For example, at a lateral carriage speed of 1 foot per second (30 cm / s) and a longitudinal oscillation frequency of 1.0 cycle per second, the distance of L3 will be 1 foot (30 cm). For a paving width 81 of 15 feet (460 cm), a lateral carriage speed of 1 foot per second (30 cm / s) corresponds to a lateral oscillation frequency of the longitudinal screed 44 of 2 cycles per minute. By maintaining a constant between the forward speed of the paver and the longitudinal oscillation frequency of the longitudinal screed 44, the distance L3 is kept constant. If the forward speed decreases (or increases), the controller 202 will detect the change in the forward speed and will decrease (or increase) the longitudinal oscillation frequency of the longitudinal screed 44 by commanding a corresponding decrease (or increase) in the rotational speed of the drive motor 92 of the eccentric drive 94. This will keep the distance L3 at a constant value.

[0076] Each point on the bottom surface of the longitudinal screed 44 will form a sine pattern similar to 228 with a wavelength L3 on the surface 18. It should be appreciated that the actual pattern 228 will not be a single sine line as shown in Figure 9 but will be multiple parallel sine surface textures that are generally a sine pattern as shown in the figure.

[0077] It should be appreciated that the paver 10 can initially be set for a given paving operation with historically preferred parameters for the forward speed of the paver, the lateral speed of the carriage 88, and the oscillation frequencies of the eccentric drives 72 and 94. For these initial settings, if the forward speed remains constant, uniform patterns such as 220 and 224 will occur. However, in actual paving situations, it is not always possible to maintain a constant forward speed of the paver. The forward speed needs to be adjusted for many reasons, such as a change in the characteristics of the incoming concrete material provided at position 16A (see Figure 2),such as changes in environmental conditions. With a paver using the prior art, any change in the forward speed will result in a change in the resulting surface pattern produced by the transverse screed 42 and / or the longitudinal screed 44. However, with the system of the present invention, the controller 202 can monitor the forward speed via the forward speed sensor 116 and can generate command signals to control the oscillation frequency of the transverse screed 42 and / or the longitudinal screed 44, so as to maintain a constant relationship between the forward speed and the oscillation frequency of the transverse screed 42 and / or the longitudinal screed 44. For the longitudinal screed 44, this includes the control of the transverse oscillation frequency and the longitudinal oscillation frequency.

[0078] For example, a method of operating the slipform paver 10 can be described as including the following steps:

[0079] (a) As the paver 10 moves forward in the paving direction 12, a large amount of concrete 16A, 16B is molded with the slipform mold 24 to form an unhardened concrete structure 16;

[0080] (b) Bring the upper surface 18 of the unhardened concrete structure 16 into engagement with at least one screed 42, 44 supported behind the slipform mold 24, and oscillate at least one screed 42, 44 transversely to the paving direction 12 to level the upper surface 18;

[0081] (c) Monitor the forward speed of the slipform paver with the controller 202; and

[0082] (d) Automatically control the transverse oscillation frequency of at least one screed 42, 44 with the controller 202 such that a constant relationship is maintained between the forward speed and the transverse oscillation frequency, thereby forming a constant surface pattern 220, 224 on the upper surface 18 of the unhardened concrete structure 16.

[0083] In the case where at least one screed 41 further includes a longitudinal screed 44, step (b) may include oscillating the longitudinal screed 44 parallel to the paving direction 12 while the longitudinal screed 44 oscillates transversely to the paving direction 12; and step (d) may include automatically controlling the longitudinal oscillation frequency of the longitudinal screed with the controller 202 such that a constant relationship is maintained between the forward speed and the longitudinal oscillation frequency.

[0084] Therefore, it can be seen that the devices and methods of the present disclosure readily achieve the objects and advantages mentioned and those inherent therein. Although certain preferred embodiments of the present disclosure have been illustrated and described for the purposes of the present field, many changes can be made by those skilled in the art to the arrangement and construction of the components and steps, and such changes are covered within the scope and spirit of the present disclosure as defined by the appended claims. Each disclosed feature or embodiment can be combined with any other disclosed feature or embodiment.

Claims

1. A slipform paver, comprising: A machine frame: A plurality of ground-engaging wheels or tracks for supporting the machine frame from the ground surface; A slipform mold supported from the machine frame for molding a large amount of concrete into a formed and unhardened concrete structure as the paver moves forward in the paving direction, the slipform mold having a mold width extending transversely to the paving direction; At least one screed beam supported behind the slipform mold for engaging the upper surface of the formed and unhardened concrete structure to level the upper surface, the at least one screed beam configured to oscillate transversely to the paving direction; At least one forward speed sensor configured to provide a forward speed signal corresponding to the forward speed of the slipform paver in the paving direction; And A controller configured to receive the forward speed signal and generate a command signal to control the transverse oscillation frequency of at least one screed beam such that a constant relationship is maintained between the forward speed and the transverse oscillation frequency.

2. The slipform paver according to claim 1, wherein: At least one screed beam includes a transverse screed beam having an elongated shape with its longest dimension extending transversely across at least a majority of the mold width.

3. The slipform paver according to claim 2, characterized in that Further comprising: A transverse oscillation frequency sensor configured to provide a transverse oscillation frequency signal corresponding to the transverse oscillation frequency of the transverse screed beam.

4. The slipform paver according to claim 3, characterized in that Further comprising: A drive motor capable of rotatably driving an eccentric drive connected to the transverse screed beam to generate the transverse oscillation of the transverse screed beam; And Wherein the transverse oscillation frequency sensor is configured to detect the rotational speed of the drive motor.

5. The slipform paver according to claim 2, wherein: At least one screed beam further includes a longitudinal screed beam having an elongated shape with its longest dimension extending parallel to the paving direction.

6. The slipform paver according to claim 5, wherein: The longitudinal screed beam also oscillates parallel to the paving direction while oscillating transversely to the paving direction; and The controller is further configured to generate a command signal to control the longitudinal oscillation frequency of the longitudinal screed beam such that a constant relationship is maintained between the forward speed and the longitudinal oscillation frequency.

7. The slipform paver according to claim 1, wherein: At least one screed beam includes a longitudinal screed beam having an elongated shape with its longest dimension extending parallel to the paving direction.

8. The slipform paver according to claim 7, wherein: The longitudinal screed beam also oscillates parallel to the paving direction while oscillating transversely to the paving direction; and The controller is further configured to generate a command signal to control the longitudinal oscillation frequency of the longitudinal screed beam such that a constant relationship is maintained between the forward speed and the longitudinal oscillation frequency.

9. The slipform paver according to claim 8, characterized in that Further comprising: A transverse oscillation frequency sensor configured to provide a transverse oscillation frequency signal corresponding to the transverse oscillation frequency of the longitudinal screed beam; A longitudinal oscillation frequency sensor configured to provide a longitudinal oscillation frequency signal corresponding to the longitudinal oscillation frequency of the longitudinal screed beam; and The controller is further configured to receive the lateral oscillation frequency signal and the longitudinal oscillation frequency signal.

10. The slipform paver according to claim 9, characterized in that Further comprising: At least one winch configured to pull a carriage carrying the longitudinal leveling beam left and right across the width of the mold; and Wherein the lateral oscillation frequency sensor is configured to detect the rotational speed of the at least one winch.

11. The slipform paver according to claim 9, characterized in that Further comprising: A drive motor rotatably driving an eccentric driver connected to the longitudinal leveling beam to generate longitudinal oscillations of the longitudinal leveling beam; And Wherein the longitudinal oscillation frequency sensor is configured to detect the rotational speed of the drive motor.

12. The slipform paver according to claim 1, wherein Further comprising: A lateral oscillation frequency sensor configured to provide a lateral oscillation frequency signal corresponding to the lateral oscillation frequency of the at least one leveling beam.

13. The slipform paver according to claim 1, characterized in that: The mold width of the slipform mold is an adjustable mold width.

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