Automatic leveling device with adjustable orientation setting

An automatic leveling device includes a motor mounted onto a frame, a linear actuator coupled to the motor, and a slideable bail assembly coupled to the linear actuator. The bail assembly is attached to the frame. The frame is configured to attach to a lifting beam, which is attached to a load surface. A controller assembly has a sensor configured to determine an orientation of the load surface when the load is suspended. The controller assembly is configured to automatically control the motor in order to position the slideable bail assembly such that the load is suspended in a predetermined orientation.

FIELD OF THE INVENTION

This invention generally relates to an automatic leveling device.

BACKGROUND OF THE INVENTION

In industrial and construction settings, cranes are frequently used to lift and transport heavy loads. However, it is not unusual for this to be a time-consuming process as great care must be taken to properly balance the load before lifting. Furthermore, it is possible, in some instances, that some of the weight in the load may shift during transport causing a load imbalance. Depending on the severity of the imbalance, the load may shift in a way that presents safety issues for nearby workers. Accordingly, there is a need for a device that avoids the aforementioned problems associated with the lifting and transport of heavy loads using a crane.

Embodiments of the invention provide such a device. These and other advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.

BRIEF SUMMARY OF THE INVENTION

In one aspect, embodiments of the invention provide an automatic leveling device that includes a motor, a linear actuator coupled to the motor, and a slideable bail assembly coupled to the linear actuator. The bail assembly is configured to attach to a frame. A controller assembly has a sensor configured to determine an orientation of an attached load when the load is suspended. The controller assembly is configured to automatically control the motor in order to position the slideable bail assembly such that the load is suspended in a predetermined orientation.

In a particular embodiment of the invention, the bail assembly and frame are attached to a lifting beam which is attached to a surface of the load, and the controller assembly is configured to automatically position the bail assembly to keep the surface of the load in a horizontal orientation while the load is suspended. In another embodiment, the bail assembly and frame are attached to the lifting beam which is attached to a surface of the load, and the controller assembly is configured to automatically position the bail assembly to keep the surface of the load oriented at a predetermined angle with respect to horizontal while the load is suspended. It is envisioned that a wide variety of lifting beams are suitable for attachment to the bail assembly and frame. In certain embodiments, the bail assembly includes a device configured to receive a lifting hook of a crane.

The controller assembly may be configured to be powered by an AC power source, or, alternatively, it may be configured to be powered by a DC power source. In a particular embodiment, the DC power source is a battery configured to supply a voltage between 12 volts and 32 volts. However, the invention is not intended to be limited by this voltage range.

In a particular embodiment, the controller assembly includes control circuitry which uses relay logic. In an alternate embodiment, the controller assembly includes control circuitry which uses programmable logic controllers (PLCs). Furthermore, in some embodiments, the sensor is an inclination sensor. In at least one embodiment, the controller assembly includes a plurality of inclination sensors arranged to detect a first inclination about a first rotational axis and a second inclination about a second rotational axis, the first rotational axis being perpendicular to the second rotational axis.

In certain embodiments, the controller assembly includes control features that allow the user to set an angular range for the inclination sensor specifying a desired orientation for the surface of the load such that, when the inclination sensor detects an inclination of the load surface outside of the set angular range, the controller assembly automatically changes the position of the bail assembly to bring the orientation of the load surface to within the set angular range. In a more particular embodiment, the controller assembly is configured to allow the user to specify a first angular range for a first desired orientation and to specify a second angular range for a second desired orientation, wherein the first desired orientation is defined by inclination in a first direction about a rotational axis, and the second desired orientation is defined by inclination in a second direction about the rotational axis, the second direction being opposite the first direction.

In a particular embodiment, after the inclination sensor detects an inclination of the load surface outside of the set angular range, the controller assembly is configured to wait for a predetermined time period before automatically causing a change in the position of the bail assembly. In a more particular embodiment, the predetermined time period is from five milliseconds to ten seconds.

In another aspect, embodiments of the invention provide a load-lifting apparatus that includes a lifting beam configured to be attached to a load, and an automatic leveling device attached to the lifting beam. The automatic leveling device includes a motor, a linear actuator coupled to the motor, and a slideable bail assembly coupled to the linear actuator, the bail assembly configured to attach to a frame. A controller assembly has a sensor configured to determine an orientation of the attached load when the load is suspended. The controller assembly is configured to automatically control the motor in order to position the slideable bail assembly such that the load is suspended in a predetermined orientation.

In a particular embodiment, the bail assembly includes a device configured to receive a lifting hook of a crane. The bail assembly and frame are attached to a lifting beam, which is attached to a surface of the load, and the controller assembly is configured to automatically position the bail assembly to keep the surface of the load oriented at a predetermined angle with respect to horizontal while the load is suspended.

In certain embodiments, the controller assembly includes control features that allow the user to set an angular range for the sensor specifying a desired inclination for the surface of the load. When the sensor detects an inclination of the load surface outside of the set angular range, the controller assembly automatically changes the position of the bail assembly to bring the inclination of the load surface to within the set angular range. The controller assembly may also be configured to allow the user to specify a first angular range for a first desired orientation and to specify a second angular range, independent of the first angular range, for a second desired orientation. The first desired orientation is defined by inclination in a first direction about a rotational axis, and the second desired orientation is defined by inclination in a second direction about the rotational axis, and the second direction is opposite the first direction.

In some embodiments, after the sensor detects an inclination of the load surface outside of the set angular range, the controller assembly is configured to wait for a predetermined time period before automatically causing a change in the position of the bail assembly. The load-lifting apparatus may further include one of a visual alarm and an audible alarm to indicate to the user whether or not the surface of the load is within the set angular range.

In at least one embodiment, the controller assembly includes a plurality of sensors arranged to detect a first inclination about a first rotational axis and a second inclination about a second rotational axis, the first rotational axis being perpendicular to the second rotational axis. The aforementioned lifting beam may be one of a cylinder lifting beam, a twin hoist lifting beam, an adjustable lifting beam, a spreader beam, a four-point beam, and a basket sling beam.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1 and 2show, respectively, a perspective view and a plan view of an automatic leveling device100, constructed in accordance with an embodiment of the invention. The automatic leveling device100has a motor102, mounted onto a frame114, and coupled to a linear actuator104. In the embodiment shown, the motor102is an electric motor, more specifically a three-phase electric motor. However, the invention is not limited to any specific type of motor. For example, a single phase motor could be used. A control enclosure116is attached to the frame114. The control enclosure116may include motor control circuitry, various relays, terminal blocks, transformers, current monitors, fuses, and the like.

The motor102operates the linear actuator104linearly to move a bail assembly108back and forth. The linear actuator104is coupled to the bail assembly108via a shaft, such that the bail assembly108moves back and forth based on how the motor operates the linear actuator104. The bail assembly108includes a plate110and a ring112. In the embodiment ofFIGS. 1 and 2, the ring112is attached to the plate110by two looped members attached to the plate110. The ring112is configured to receive an attachment mechanism of a lifting and transport device, such as the hook of a lifting crane for example.

The bail assembly108slides along the top of the frame assembly114, which is configured to attach to a lifting beam, which is attached to the surface of a load (not shown) to be lifted and transported by a device such as the aforementioned lifting crane (not shown). The invention is not intended to be limited to any particular type of lifting beam. The types of lifting beam contemplated for use with embodiments of the invention include, but are not limited to, a cylinder lifting beam, a twin hoist lifting beam, an adjustable lifting beam, a spreader beam, a four-point beam, a rotating drum lifting beam, and a basket sling beam.

The automatic leveling device100has an auto-leveling controller122configured to automatically position the bail assembly108to keep the surface of the load in a horizontal orientation while the load is suspended. The auto-leveling controller122may be constructed such that certain parameters may be entered by the user. For example, in a typical embodiment, the auto-leveling controller122is configured to automatically position the bail assembly108to keep the surface of the load in a horizontal orientation while the load is suspended. However, in certain embodiments, the auto-leveling controller122is configured to automatically position the bail assembly108to keep the surface of the load oriented at a predetermined angle with respect to horizontal while the load is suspended.

The auto-leveling controller122accomplishes the automatic positioning of the bail assembly108via one or more inclination sensors120. The embodiments ofFIGS. 1 and 2show an automatic leveling device100with two inclination sensors120. However, alternate embodiments of the invention may have one inclination sensor120, or more than two inclination sensors120. Having two or more inclination sensors120, arranged to measure inclines for the same rotational axis, may provide redundancy should one of the sensors120malfunction. Alternatively, the measurements of multiple inclination sensors120could be averaged to potentially reduce the amount of error in any one measurement.

FIGS. 1 and 2also show an embodiment of the automatic leveling device100with two overtravel limit switches121attached to the frame assembly114. The overtravel limit switches121operate to prevent the bail assembly108from moving too far towards or away from the linear actuator104. In the event that the bail assembly108does move too far towards or away from the linear actuator104, the limit switch121operates to temporarily disable, or limit movement of, the linear actuator104until reason for the overtravel is corrected.

As shown inFIGS. 1 and 2, the inclination sensors120, while connected, either wired or wirelessly, to the auto-leveling controller122, may be positioned remotely from portions of the auto-leveling controller122. In the embodiments shown, the inclination sensors120are attached to an enclosure of the auto-leveling controller122, though the inclination sensors120could be located in an number of different locations. In specific embodiments, the auto-leveling controller122may include switches, buttons, or other suitable control features that allow the user to set an angular range for the inclination sensor120specifying a desired inclination for the surface of the load, and wherein, when the inclination sensor120detects an inclination of the load surface outside of the set angular range, the auto-leveling controller122automatically changes the position of the bail assembly108to bring the inclination of the load surface to within the set angular range. In a particular embodiment, the angular range is set in degrees, though other units of angular measurement may be used. Visual indicators, such as red and green lights could be used to show whether the suspended load is in or out of the predetermined angular range set by the user. Audible alarms may also be used for this purpose.

In a particular embodiment, the auto-leveling controller122is configured such that, after the inclination sensor120detects an inclination of the load surface outside of the set angular range, the auto-leveling controller122waits for a predetermined time period before automatically causing a change in the position of the bail assembly108. In a specific embodiment, the predetermined time period is from five milliseconds to ten seconds, though alternate embodiments include shorter and longer time periods. The auto-leveling controller122can be configured to be powered by an alternating current (AC) power source, or a direct current (DC) power source. In a particular embodiment, the controller assembly is powered by a battery configured to supply between 12 and 32 volts.

The control circuitry for the auto-leveling controller122could be implemented using relay logic or using programmable logic controllers (PLCs).FIG. 3shows a schematic diagram of the circuitry for elements of the auto-leveling controller122and for the control enclosure116, according to an embodiment of the invention. The auto-leveling controller122is shown inside the dashed square on the diagram ofFIG. 3, and includes inclination sensor120and a 24-volt DC power supply124, in this case, fed by a 120-volt AC power source.

In operation, the inclination sensors120may mounted on the inside or outside of the enclosure for the auto-leveling controller122attached to the frame assembly114, which is attached to a lifting beam, which is attached to a surface of the load. In the drawings provided, the inclinations sensors120are shown as attached to an exterior portion of the enclosure for the auto-leveling controller122, but the inclination sensors120could be located on the inside of the enclosure for the auto-leveling controller122along with relays and other electronic components of the automatic leveling device100. Additionally, embodiments of the invention include those where the inclination sensors120are located remotely from the control enclosure116and from the auto-leveling controller122, for example on various parts of the frame114. Remotely located inclination sensors120could have a wired or wireless connection to the auto-leveling controller122. Each inclination sensor120is designed to detect and measure a change in inclination about one rotational axis. The embodiment ofFIGS. 1 and 2shows an automatic leveling device100with two inclination sensors120both oriented in the same direction, and both arranged to detect and measure changes in inclination about the same rotational axis. When the load is suspended and the inclination sensors120sense that the inclination of the surface is outside of the angular range set by the user, one of at least two sensor switches126in the inclination sensor120is activated.

In an alternate embodiment, an inclination sensor120may have four or more switches126to allow the sensor120to detect and measure inclination about two rotational axes, the first rotational axis perpendicular to the second rotational axis. Alternately, two inclination sensors120(or some plurality of sensors120) arranged perpendicularly to one another could be used to detect and measure inclination about two perpendicular rotational axes. In such an embodiment, the frame114ofFIG. 1could be configured to allow for movement of the bail assembly108in two dimensions, with four inclination sensors120appropriately distributed about the surface of the load. Such an arrangement could also involve two motors102and two linear actuators104to move the bail assembly108in two dimensions. However, in these alternate embodiments, the auto-leveling controller122would not substantially depart from the schematic representation ofFIG. 3.

Activation of one of the sensor switches126operates to close one of the two sets of three relay contacts128via which power is supplied to the motor102. One set of the three relay contacts128, when closed, causes the motor102to operate the linear actuator104to move the bail assembly108towards the motor102, while the other set of the three relay contacts128, when closed, causes the motor102to operate the linear actuator104to move the bail assembly108away from the motor102. In the embodiment ofFIG. 3, when any one of the sensor switches126is closes, a corresponding timer relay130is activated. Depending on the delay time set by the user, the timer relay130will delay activation of the motor relay132that activates the relay contacts128for the motor102.

It is envisioned that the auto-leveling controller122would be programmable, and configured to accept independent angular ranges for difference orientations. The auto-leveling controller122may be configured to allow the user to specify a first angular range for a first desired orientation, or inclination, and to specify a second angular range for a second desired orientation or inclination. For example, one end of a suspended load surface may be allowed to dip one degree below horizontal in the first desired orientation, but allowed to rise three degrees above horizontal in the second desired orientation, before the auto-leveling controller122automatically repositions the bail assembly108to bring the load surface back within the predetermined angular range.

FIG. 4shows a perspective view of the automatic leveling device100attached to a rotating drum lifting beam150, according to an embodiment of the invention. A lifting beam is a structural member designed to be attached to a load to facilitate the lifting and transport of the load, for example via some type of crane. WhileFIG. 4depicts rotating drum lifting beam150, the automatic leveling device100could be configured to attach to a wide variety of different lifting beam types. These lifting beams could include, but are not necessarily limited to, various types of cylinder lifting beams, twin hoist lifting beams, adjustable lifting beams, spreader beams, four-point beams, basket sling beams, etc.

A manual pendant140allows the user to exert manual control over the automatic leveling device100, or to set, reset, or delete angular ranges of inclination in the auto-leveling controller122. The manual pendant140may include switches, buttons, or other suitable control features that allow the user to set the angular range for the inclination sensor120specifying a desired inclination for the surface of the load, for example, in degrees, or other suitable units of angular measurement. As can be seen fromFIG. 3, the auto-leveling controller122is connected to the leveler motor102. Power to the leveler motor102is common with power to the drum motor152for the rotating drum lifting beam150. Operation of the drum motor152may also be controlled by the user using the manual pendant140. While the manual pendant140shown inFIG. 4is wired, a wireless pendant could also be used. In a wired configuration, the manual pendant140may be wired to the auto-leveling controller122, or to the control enclosure116. In an alternate embodiment, the automatic leveling device100could be controlled via a control interface on the unit itself rather than remotely using the manual pendant140.

While the rotating drum lifting beam150, or any suitable lifting beam, could be manufactured to include the automatic leveling device100, it is also envisioned that the automatic leveling device100could be designed to be retrofitted to existing lifting beams.