Patent Description:
A compaction machine may include a chassis and two vibrating drums rotatably mounted to the chassis so that the drums compact a work surface (e.g., an asphalt mat) as the compaction machine moves thereon. A compaction machine may include eccentric masses (also referred to as eccentric shafts) in the respective drums that are rotated at speed to generate vibrations that are transmitted as impacts by the drums to the work surface. Various examples of compaction machines are discussed, for example, in <CIT> entitled "Vibrating Roller," <CIT> entitled "Vibratory System For Compactor Vehicles," and <CIT> entitled "Apparatus And Method For Controlling the Start Up And Phase Relationship Between Eccentric Assemblies.

Document <CIT> relates to a compacting machine having a vibrating drum, wherein two accelerometers are used for determining the acceleration of the drum.

Notwithstanding known compaction machines, there continues to exist a need in the art for compaction machines, methods, and/or controllers providing increased efficiency of operation and/or improved compaction.

A vibratory compaction machine according to one embodiment comprises a chassis, at least one drum rotatable about an axis that faces in a Y-axial direction and mounted to the chassis to allow rotation of the drum over a work surface, at least one vibration mechanism configured to generate vibrations that are transmitted as impacts directed in a Z-axial direction by the at least one drum to the work surface, the at least one vibration mechanism provided with a plurality of different amplitude settings, and a control system configured to measure acceleration forces of the at least one drum in a direction that substantially corresponds to an X-axial direction, wherein the acceleration forces are generated by the vibration mechanism and the X-axial direction extends in a direction that is substantially orthogonal to the Y-axial direction and the Z-axial direction, the control system determining which of the plurality of drum amplitude settings the vibration mechanism is operating at from the measured acceleration forces of the at least one drum in the direction that substantially corresponds to an X-axial direction.

According to another embodiment, a method for operating a vibratory compaction machine provided with a chassis, at least one drum rotatable about an axis that faces in a Y-axial direction and mounted to the chassis to allow rotation of the drum over a work surface, and at least one vibration mechanism provided with a plurality of different amplitude settings and configured to generate vibrations that are transmitted as impacts directed in a Z-axial direction by the at least one drum to the work surface, the at least one vibration mechanism, comprises the steps of operating the vibration mechanism to generate acceleration forces in the drum in an X-axial direction, wherein the X-axial direction extends in a direction that is substantially orthogonal to the Y-axial direction and the Z-axial direction, using a control system provided on the vibratory compaction machine to measure acceleration forces of the at least one drum in a direction that substantially corresponds to the X-axial direction, wherein the acceleration forces are generated by the vibration mechanism, and using the control system to determine which of the plurality of drum amplitude settings the vibration mechanism is operating at from the measured acceleration forces of the at least one drum in the direction that substantially corresponds to an X-axial direction.

According to an aspect of an embodiment, a vibratory compaction machine comprises a chassis, at least one drum rotatable about an axis that faces in a Y-axial direction and mounted to the chassis to allow rotation of the drum over a work surface, at least one vibration mechanism configured to generate vibrations that are transmitted as impacts directed in a Z-axial direction by the at least one drum to the work surface, the at least one vibration mechanism provided with a plurality of different amplitude settings, and a control system configured to measure acceleration forces of the at least one drum in a direction that substantially corresponds to an X-axial direction, wherein the acceleration forces are generated by the vibration mechanism and the X-axial direction extends in a direction that is substantially orthogonal to the Y-axial direction and the Z-axial direction, the control system determining which of the plurality of drum amplitude settings the vibration mechanism is operating at from the measured acceleration forces of the at least one drum in the direction that substantially corresponds to an X-axial direction.

According to an aspect of an embodiment, the at least one vibration mechanism is provided with a plurality of different frequency settings and the control system selects a frequency setting from the plurality of different frequency settings according to the determined amplitude setting, whereby different determined amplitude settings result in selection of different frequency settings, and the control system operates the vibration system at the selected frequency.

According to an aspect of an embodiment, the at least one vibration mechanism is provided with a plurality of frequency settings, wherein each of the plurality of frequency settings corresponds to one of the plurality of amplitude settings such that each of the plurality of different frequency settings may be selectively applied according to the determined amplitude setting and the control system selects one of the plurality of frequency settings according to the determined amplitude setting, and the control system operates the vibration system at the one selected frequency.

According to an aspect of an embodiment, the at least one vibration mechanism is provided with a plurality of frequency settings, wherein each of the plurality of frequency settings corresponds to one of the plurality of amplitude settings such that each of the plurality of different frequency settings may be selectively applied according to the determined amplitude setting and the control system selects one of the plurality of frequency settings according to the determined amplitude setting, operates the vibration system at the selected frequency, and selects a new frequency setting in response to a change to the determined amplitude and operates the vibration system at the new selected frequency.

According to an aspect of an embodiment, the at least one vibration mechanism is provided with a plurality of frequency settings, wherein each of the plurality of frequency settings corresponds to one of the plurality of amplitude settings such that each of the plurality of different frequency settings may be selectively applied according to the determined amplitude setting and the control system selects one of the plurality of frequency settings according to the determined amplitude setting, operates the vibration system at the selected frequency, remeasures acceleration forces generated by the vibration mechanism in the direction that substantially corresponds to the X-axial direction, re-determines which of the plurality of drum amplitude settings the vibration mechanism is operating at from the remeasured acceleration forces generated by the vibration mechanism in a direction that substantially corresponds to an X-axial direction, selects a different one of the plurality of frequency settings when the re-determined amplitude setting is different from the determined amplitude setting and corresponds to the selected different one of the plurality of frequency settings, and operates the vibration system at the different selected frequency.

According to an aspect of an embodiment, the at least one vibration mechanism is provided with a plurality of frequency settings, wherein each of the plurality of frequency settings corresponds to one of the plurality of amplitude settings such that each of the plurality of different frequency settings may be selectively applied according to the determined amplitude setting and the control system selects one of the plurality of frequency settings according to the determined amplitude setting, operates the vibration system at the selected frequency, remeasures acceleration forces acceleration forces of the at least one drum in the direction that substantially corresponds to an X-axial direction, re-determines which of the plurality of drum amplitude settings the vibration mechanism is operating at from the remeasured acceleration forces, selects a different one of the plurality of frequency settings that is greater than the frequency of the selected frequency when the re-determined amplitude setting is less than the amplitude of the determined amplitude setting and corresponds to the selected different one of the plurality of frequency settings; and operates the vibration system at the different selected frequency.

According to an aspect of an embodiment, the control system includes accelerometers located on a carrier plate that supports a drum axle rotation bearing of the at least one drum in a manner that allows for rotation of the at least one drum relative to the carrier plate and the carrier plate is located inside the at least one drum axially inward from vibration isolators, which are interposed between carrier plate and a frame so that drum vibrations imparted to the carrier plate by the drum axle rotation bearings are damped and reduced after being measured by the accelerometers and before being transmitted to a frame of the vibration compactor.

According to an aspect of an embodiment, the control system includes a controller and at least one accelerometer.

According to an aspect of an embodiment, a method for operating a vibratory compaction machine provided with a chassis, at least one drum rotatable about an axis that faces in a Y-axial direction and mounted to the chassis to allow rotation of the drum over a work surface, and at least one vibration mechanism provided with a plurality of different amplitude settings and configured to generate vibrations that are transmitted as impacts directed in a Z-axial direction by the at least one drum to the work surface, the at least one vibration mechanism, comprises the steps of operating the vibration mechanism to generate acceleration forces in the drum in an X-axial direction, wherein the X-axial direction extends in a direction that is substantially orthogonal to the Y-axial direction and the Z-axial direction, using a control system that includes at least one accelerometer and a controller and is provided on the vibratory compaction machine to measure acceleration forces of the at least one drum in a direction that substantially corresponds to the X-axial direction, wherein the acceleration forces are generated by the vibration mechanism and using the control system to determine which of the plurality of drum amplitude settings the vibration mechanism is operating at from the measured acceleration forces of the at least one drum in the direction that substantially corresponds to an X-axial direction.

According to an aspect of an embodiment, the at least one vibration mechanism is provided with a plurality of different frequency settings and the method further comprises the steps of using the control system to select a frequency setting from the plurality of different frequency settings according to the determined amplitude setting, whereby different determined amplitude settings result in selection of different frequency settings and using the control system to operate the vibration system at the selected frequency.

According to an aspect of an embodiment, the at least one vibration mechanism is provided with a plurality of different frequency settings, each of the plurality of frequency settings corresponding to one of the plurality of amplitude settings such that each of the plurality of different frequency settings may be selectively applied according to the determined amplitude setting and the method further comprises the steps of using the control system to select one of the plurality of frequency settings from the according to the determined amplitude setting and using the control system to operate the vibration system at the one selected frequency.

According to an aspect of an embodiment, the at least one vibration mechanism is provided with a plurality of frequency settings, each of the plurality of frequency settings corresponding to one of the plurality of amplitude settings such that each of the plurality of different frequency settings may be selectively applied according to the determined amplitude setting and the method further comprises the steps of using the control system to select one of the plurality of frequency settings according to the determined amplitude setting, operate the vibration system at the selected frequency, select a new frequency setting in response to a change to the determined amplitude, and operate the vibration system at the new selected frequency.

The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in a constitute a part of this application, illustrate certain non-limiting embodiments of inventive concepts. In the drawings:.

These embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of present inventive concepts to those skilled in the art. Any two or more embodiments described below may be combined in any way with each other. Moreover, certain details of the described embodiments may be modified, omitted, or expanded upon without departing from the scope of the described subject matter.

<FIG> illustrates a self-propelled compaction machine according to some embodiments of inventive concepts. The compaction machine of <FIG> includes a chassis <NUM>, <NUM>, first (e.g., leading) and second (e.g., trailing) rotatable drums <NUM> and <NUM> at the front and back at of the chassis <NUM>, <NUM>, and a driver station including a seat <NUM> and a steering mechanism <NUM> (e.g., a steering wheel) to provide driver control of the compaction machine. Moreover, each drum may be coupled to the chassis <NUM>, <NUM> using respective frames, as at <NUM>, <NUM> (also referred to as yokes). One or both drums <NUM>, <NUM> may be driven by a drive motor over a work surface <NUM>. Although <FIG> shows a dual drum compaction machine, in alternative embodiments, a single compaction drum may be provided.

Each of drums <NUM> and <NUM> also includes a vibration mechanism <NUM>. Within the scope of the present embodiment the vibration mechanism <NUM> may be any device or devices, such as, for example, a variety of eccentric rotating mass systems, that are capable of generating vibrations transmitted as impacts by the first and second drums <NUM> and <NUM> to the work surface <NUM>. By way of example, the vibration mechanism <NUM> may be provided using: one eccentric assembly including a single eccentric shaft (single amplitude machine); one eccentric assembly including two eccentric shafts; or multiple eccentric assemblies including single and/or double eccentric shaft systems (oscillatory machines). Those of ordinary skill in the art will appreciate that numerous vibration mechanisms are known, and the scope of the present embodiment is not limited to the particular vibration system <NUM> illustrated. While lesser or more complex eccentric systems may be employed within the scope of the present embodiment, for the sake of simplicity and brevity, <FIG>, shows a relatively simple vibration mechanism <NUM> that includes a single rotatable eccentric mass <NUM>, which may, for example, be driven by an eccentric motor <NUM> and supported by a bearing <NUM>. Those of ordinary skill in the art will appreciate that the center of mass of the eccentric mass <NUM> is imbalanced and does not reside on the rotational axis <NUM> about which the eccentric mass <NUM> rotates. Those of ordinary skill in the art will also appreciate that, for purposes of increasing compaction efficiency, the imbalanced nature of the eccentric mass <NUM> of each drum <NUM>, <NUM> imparts vibration to the drums <NUM>, <NUM> as the eccentric mass rotates about rotational axis <NUM>. Those of ordinary skill in the art will also appreciate that as the eccentric mass <NUM> rotates that the eccentric mass <NUM> generates a downward force that is transmitted as an impact by the drums <NUM>, <NUM> to the work surface <NUM>. Furthermore, those of ordinary skill in the art will appreciate that as the eccentric mass <NUM> rotates, the eccentric mass also generates an upward force which urges the drums <NUM>, <NUM> upward, relative to the occurrence of a downward impact force. The eccentric system <NUM> is preferably driven by hydraulic motors <NUM>, however, it is within the scope of the present embodiment to utilize electric motors <NUM>, as well.

During operation, eccentric mass <NUM> may be rotated to generate vibrations transmitted as impacts by the first and second drums <NUM> and <NUM> to the work surface <NUM>. Those of ordinary skill in the art will appreciate that the amplitude of the vibration system <NUM> and the impacts of the present embodiment may be adjusted by increasing or decreasing the eccentricity of center of mass of the eccentric <NUM> relative to the rotational axis <NUM>, as shown by a comparison between <FIG>, such that a plurality of amplitude settings are available for the vibration system <NUM>. Those of ordinary skill in the art will appreciate that the frequency of impacts may be adjusted by increasing or decreasing the speed of rotation of the eccentric <NUM> about the rotational axis <NUM>, such that a plurality of frequency settings are available for the vibration system <NUM>. Those of ordinary skill in the art will appreciate that the optimal frequency of impacts varies according to the amplitude setting of the vibration system <NUM>. By way of example, those of ordinary skill in the art will appreciate that as amplitude increases it may be desirable to decrease the frequency to prevent undue wear and tear on the eccentric assembly bearings and other components of the machine.

According to the invention, a control system <NUM> is provided for automatically detecting the amplitude setting of the vibration system <NUM>. According to another aspect of the present embodiment, the control system <NUM> automatically determines and selects the appropriate corresponding frequency setting for the vibration system <NUM> at the detected amplitude setting. According to another aspect of the present embodiment, the control system <NUM> preferably operates the vibration system at the selected frequency setting. According to yet another aspect of the present embodiment, the control system <NUM> may operate the vibration system <NUM> at the fastest frequency setting for the vibration system <NUM> at the detected amplitude setting.

Turning now to <FIG>, a control system <NUM> may include controller <NUM> configured to automatically control the rotational speed/frequency of the vibration mechanisms <NUM> of the first and second drums <NUM> and <NUM> responsive to the detected amplitude setting of the vibration mechanisms <NUM> of the first and second drums <NUM> and <NUM>. Also shown, in <FIG> and <FIG>, control system <NUM> may also include first and second accelerometers <NUM>, <NUM> that measure acceleration forces Fx of drums <NUM> and <NUM> in X-axis direction, which is substantially orthogonal to Z-axis direction in which the downward impact forces are directed and substantially orthogonal to the Y-axis direction of the rotational axis <NUM>. Those of ordinary skill in the art will appreciate that the acceleration forces Fx are imparted to the drums <NUM> and <NUM> by the vibration systems <NUM>.

Typically, in compactors acceleration data on a compactor drum is collected using the Z-axis of the drum, which can be used to calculate the density of the material compacted. The present embodiment, in contrast, orients the accelerometers <NUM>, <NUM> to collect acceleration data in the X-axis direction of the drums <NUM>, <NUM> so that X-axis direction displacement of the drums <NUM>, <NUM> may be calculated. Based on the measured acceleration data and calculated displacement, the amplitude setting of the vibration system <NUM> may be determined and the appropriate vibration setting can be applied. Accordingly, control logic of controller <NUM> may monitor amplitude and adjust frequency to achieve a desired performance. By way of example, in certain operational settings, the fastest frequency setting for the vibration system <NUM> at the detected amplitude setting can be applied by the control system <NUM>. As shown in <FIG>, in the present embodiment, controller <NUM> may adjust the rotational speed of the eccentric <NUM> by sending a signal to control the flow of hydraulic fluid from pump <NUM> to hydraulic motors <NUM> which drive eccentric masses <NUM>. By way of example the signal may command the same hydraulic flow to substantially maintain an existing frequency of rotation when the determined amplitude detected is constant and may increase or decrease the hydraulic flow in response to a sensed change in the amplitude in order to increase or decrease the frequency of rotation of the eccentric masses <NUM> of drums <NUM>, <NUM> in response to a sensed change in amplitude by accelerometers <NUM>, <NUM>.

Turning now to <FIG>, the accelerometers <NUM>, <NUM> are preferably located on carrier plates <NUM>, which support drum axle rotation bearings <NUM> of the drums <NUM>, <NUM> in a manner that allows for rotation of the drums <NUM>, <NUM> relative to the carrier plates <NUM> and frame or yokes and in a manner that causes the carrier plates <NUM> to accelerate with the drums <NUM>, <NUM> in response to rotation of the vibration system <NUM>. As shown in <FIG>, axle bearing <NUM> may be located opposite the drive motor <NUM> used to propel the drums <NUM>, <NUM>. Also shown, the accelerometers <NUM>, <NUM> are located inside the drum and are positioned to measure back and forth acceleration forces of the drums <NUM>, <NUM> in X-axis direction as the eccentric mass <NUM> rotates. Also shown in <FIG>, the carrier plates are located inside drums <NUM>, <NUM> axially inward from vibration isolators <NUM>, which are interposed between carrier plate <NUM> and frame or yokes <NUM>, so that drum accelerations applied to the carrier plate <NUM> by the drum axle rotation bearings <NUM> of the drum propulsion system are damped and reduced before being transmitted to the frame or yokes <NUM>. The accelerometers <NUM>, <NUM> therefore, preferably, are positioned inside the drums <NUM>, <NUM> to directly measure back and forth acceleration forces of the drums <NUM>, <NUM> in the X-axis direction before such forces are dampened by any vibration isolators or dampers, as at <NUM>. Within the scope of the present embodiment, the accelerometers <NUM>, <NUM> may be positioned to measure accelerations in a fixed direction that substantially corresponds to the X-axis direction or the accelerometers <NUM>, <NUM> may be combined in an inertial measurement unit ("IMU"), which is a device that uses a combination of an accelerometer, gyroscope, and sometimes magnetometer in order to more precisely determine the accelerations of the drums <NUM>, <NUM> in the X-axis direction.

Turning now to <FIG>, for the calculation process, using the X-axis provides better data than using the Z-axis. The X-axis data allows for a full range displacement of drum motion unaffected by the sudden impact of the ground that the Z-axis would capture. The benefit of collecting X-axis data is that there is more useable data to calculate displacement, opposed to having to wait a full eccentric rotation for the next set of usable data from the Z-axis data gathering. This also shortens the time needed for the drum to reach working vibration speeds.

Turning now back to <FIG>, accelerometers <NUM>, <NUM> measure and send acceleration data to the controller <NUM>, which determines the amplitude from acceleration data. The amplitude may be determined based on an algorithm or by referencing collected acceleration data to corresponding amplitudes, which may, for example, be stored in one or more look up tables.

Controller <NUM> may include a processor coupled with a memory and an interface circuit, and the interface circuit may provide communication between the components of the control system <NUM>. The processor may thus be configured to execute computer program code in the memory (described below as a non-transitory computer readable medium) to perform at least some of the operations discussed above with respect to <FIG>. The control system <NUM> of <FIG> may thus control the frequencies of the rotation of eccentric masses <NUM> in the drums <NUM>, <NUM>. Control logic of controller <NUM> may monitor the amplitude setting of the eccentric masses <NUM> in the drums <NUM>, <NUM> and maintain or adjust the frequency of the eccentric masses <NUM> of the trailing drum to time the impacts accordingly. In addition to operating the eccentric masses <NUM> at the fastest rotational speed or frequency for a detected amplitude setting, other frequency settings may as be applied based on the detected amplitude setting. By way of example, the eccentric masses <NUM> may be rotated at a speed that provides the most efficient compaction for a particular material make up being compacted.

In the above-description of various embodiments of the present disclosure, it is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

When an element is referred to as being "connected", "coupled", "responsive", "mounted", or variants thereof to another element, it can be directly connected, coupled, responsive, or mounted to the other element or intervening elements may be present. In contrast, when an element is referred to as being "directly connected", "directly coupled", "directly responsive", "directly mounted" or variants thereof to another element, there are no intervening elements present. The term "and/or" and its abbreviation "/" include any and all combinations of one or more of the associated listed items.

As used herein, the terms "comprise", "comprising", "comprises", "include", "including", "includes", "have", "has", "having", or variants thereof are open-ended, and include one or more stated features, integers, elements, steps, components or functions but do not preclude the presence or addition of one or more other features, integers, elements, steps, components, functions or groups thereof. Furthermore, as used herein, the common abbreviation "e.g.", which derives from the Latin phrase "exempli gratia," may be used to introduce or specify a general example or examples of a previously mentioned item and is not intended to be limiting of such item.

Claim 1:
A vibratory compaction machine comprising:
a chassis (<NUM>, <NUM>);
at least one drum (<NUM>, <NUM>) rotatable about an axis that faces in a Y-axial direction and mounted to the chassis (<NUM>, <NUM>) to allow rotation of the drum (<NUM>, <NUM>) over a work surface (<NUM>);
at least one vibration mechanism (<NUM>) configured to generate vibrations that are transmitted as impacts directed in a Z-axial direction by the at least one drum (<NUM>, <NUM>) to the work surface (<NUM>), the at least one vibration mechanism (<NUM>) provided with a plurality of different amplitude settings; and
a control system (<NUM>) configured to measure acceleration forces of the at least one drum in a direction that substantially corresponds to an X-axial direction, wherein the acceleration forces are generated by the vibration mechanism (<NUM>) and the X-axial direction extends in a direction that is substantially orthogonal to the Y-axial direction and the Z-axial direction, characterized in that, the control system (<NUM>) is further configured to determine which of the plurality of drum amplitude settings the vibration mechanism (<NUM>) is operating at from the measured acceleration forces of the at least one drum (<NUM>, <NUM>) in the direction that substantially corresponds to the X-axial direction.