Tensile truss mast
09908750 ยท 2018-03-06
Assignee
Inventors
- Albert J. Sturm, Jr. (Stillwater, MN, US)
- Michael Hennessey (Prior Lake, MN, US)
- Mark Guterman (Eagan, MN, US)
Cpc classification
International classification
Abstract
Hoist systems are provided. In one embodiment, a hoist system includes a lower platform, an upper platform, a plurality of flexible members, and a plurality of hoists. The upper platform has a plurality of rotatable support arms. The flexible members connect the rotatable support arms to the lower platform and can be extended and retracted using the plurality of hoists. If desired, the upper platform includes a plurality adjustable length support arms, and actuators may be used to extend and retract the support arms.
Claims
1. A hoist system comprising: a support structure; a lower platform having a lower reference axis; an upper platform mounted to the support structure for at least partial rotation about an axis; a drive connected to the upper platform configured to rotate the upper platform; a plurality of at least three support arms extending radially from the axis and mounted to the upper platform to rotate about the axis therewith, wherein remote ends of the support arms are spaced apart from each other at equal angular intervals about the axis; a plurality of at least six flexible members that connects the plurality of at least three support arms to the lower platform, wherein two flexible members of the plurality of at least six flexible member comprise a pair of flexible members extends over a remote end of each support arm downwardly to the lower platform and also toward the axis, wherein the flexible members are joined to the lower platform at locations spaced apart from each other, wherein, when the axis is aligned with the lower reference axis, the flexible members are arranged in a first group and a second group, each group comprising at least three flexible members spaced apart from each other about the axis at equal angular intervals and each flexible member of each group extending between the upper platform and the lower platform at a same angle with respect to the axis as each other flexible member in the same associated group when the axis is aligned with the lower reference axis; a plurality of at least six hoists that extends and retracts the plurality of at least six flexible members, each of the at least six flexible members operably coupled to, and extended and retracted by, a different one of the at least six hoists in order to move the lower platform vertically and laterally within a work envelope, and wherein each hoist is configured to extend and retract the associated flexible member connected thereto independently from the other plurality of five other hoists, and wherein the plurality of at least six hoists are mounted in pairs to each of the at least three support arms; and a controller operably connected to the drive to selectively rotate the upper platform and connected to each hoist to operate each hoist independently from the other hoists to move the lower platform vertically, laterally and with angular movements comprising pitch and roll with respect to the axis within the work envelope, wherein lateral movement includes extension of the flexible members at different lengths to move the lower platform laterally with respect to the axis.
2. The hoist system of claim 1, and further comprising: a weighted collar that is suspended from the upper platform and that supports a spine extending from the lower platform.
3. The hoist system of claim 2, wherein the spine extending from the lower platform has a cylindrical shape and fits through a cylindrical aperture in the weighted collar.
4. The hoist system of claim 2, wherein the spine extending from the lower platform has a shape that is keyed to a shape of an aperture in the weighted collar.
5. The hoist system of claim 1, wherein each of the plurality of flexible members utilizes at least one pulley on the lower platform and has an attachment point on one of the plurality of rotatable support arms.
6. The hoist system of claim 5, wherein each of the plurality of flexible members extends from one of the plurality of rotatable support arms and the attachment point for the flexible member is on the same one of the plurality of rotatable support arms.
7. The hoist system of claim 5, wherein each of the plurality of flexible members extends from one of the plurality of rotatable support arms and the attachment point for the flexible member is on a different one of the plurality of rotatable support arms.
8. The hoist system of claim 5, wherein each of the plurality of flexible members utilizes two or more pulleys on the lower platform.
9. The hoist system of claim 1, and further comprising: a plurality of sensors, each sensor being configured to provide an output corresponding to tension in at least one of the plurality of flexible members.
10. The hoist system of claim 9, and wherein the controller is configured to receive the outputs from the plurality of sensors and provide compensation for elongation of the plurality of flexible members during positioning of the lower platform.
11. The hoist system of claim 10, and wherein the controller is configured to receive the outputs from the plurality of sensors and utilize the outputs to determine if slack is present in one or more of the plurality of flexible members.
12. A hoist system comprising: a support structure; a lower platform; a set of pulleys having a pulley thereof mounted to the lower platform at each of three locations spaced apart from each other about a lower reference axis at equal angular intervals; an upper platform mounted to the support structure; a plurality of adjustable length support arms extending radially from a center axis, the support arms being mounted to the upper platform to move therewith, wherein remote ends of the support arms are symmetrically spaced apart from each other and about the center axis, and wherein each support arm is independently adjustable in length; a plurality of three flexible members that connects the plurality of adjustable length support arms to the lower platform, each of the flexible members extending downwardly to the lower platform and also toward the center axis; wherein each flexible member engages one of the pulleys on the lower platform, wherein each flexible member has a first portion extending from one of the support arms to one of the pulleys on the lower platform and a second portion extending from said one of the pulleys on the lower platform to the support arm having a remote end fixed to the upper platform at each of three locations that are spaced apart from each other about the center axis at equal angular intervals, and wherein when the center axis is aligned with the lower reference axis, the first portions are spaced apart at equal angular intervals about the center axis and have a same angle with respect to the center axis as each other first portion; and the second portions are spaced apart at equal angular intervals about the center axis and have a same angle with respect to the center axis as each other second portion; and a plurality of hoists that extends and retracts the plurality of flexible members, wherein a hoist thereof is mounted to one of the support arms; and a controller operably coupled to each support arm to selectively adjust a length thereof and operably coupled to each of the hoists, wherein the controller is configured to operate each hoist of the plurality of hoists independently from the other hoists to move the lower platform vertically, laterally and with angular movements comprising pitch and roll with respect to the center axis within a work envelope.
13. The hoist system of claim 12, and further comprising: a plurality of sensors, each sensor being configured to provide an output corresponding to tension in at least one of the plurality of flexible members.
14. The hoist system of claim 13, and wherein the controller is configured to receive the outputs from the plurality of sensors and provide compensation for elongation of the plurality of flexible members during positioning of the lower platform.
15. A hoist system comprising a lower platform having a lower reference axis; a first set of pulleys having a pulley thereof mounted to the lower platform at each of three locations spaced apart from each other about a lower reference axis at equal angular intervals; a second set of pulleys having a pulley thereof mounted to the lower platform at each of three locations spaced apart from each other about the lower reference axis at equal angular intervals; an upper platform having a rotational axis and a plurality of support arms; a drive connected to the upper platform configured to rotate the upper platform about the rotational axis; a plurality of extendable and retractable flexible members, each flexible member being guided by one of the first set of pulleys and one of the second set of pulleys so as to form a couple when the corresponding flexible member is in tension and having a remote end joined to the upper platform, wherein each flexible member has a first portion extending from one of the support arms to one of the pulleys of the first set on the lower platform and a second portion extending from one of the pulleys of the second set on the lower platform, and wherein when the rotational axis is aligned with the lower reference axis, the first portions are spaced apart at equal angular intervals about the rotational axis and have a same angle with respect to the rotational axis as each other first portion; and the second portions are spaced apart at equal angular intervals about the rotational axis and have a same angle with respect to the rotational axis as each other second portion; a plurality of hoists, each hoist extending and retracting one of the plurality of flexible members to move the lower platform vertically and laterally and with angular movements comprising pitch, yaw and roll within a work envelope with respect to the rotational axis; and a controller operably connected to the drive to selectively rotate the upper platform and connected to each hoist to operate each hoist independently from the other hoists to move the lower platform vertically, laterally and with angular movements comprising pitch and roll with respect to the rotational axis within the work envelope, wherein lateral movement includes extension of the flexible members at different lengths to move the lower platform laterally with respect to the axis.
16. The hoist system of claim 15, wherein each couple comprises a third portion of the flexible member extending between the associated pulley of the first set of pulleys and the associated pulley of the second set of pulleys, and wherein each of said third portions extends along a line that is parallel to or in the plane of the lower platform.
17. The hoist system of claim 15, wherein each couple comprises a third portion of the flexible member extending between the associated pulley of the first set of pulleys and the associated pulley of the second set of pulleys, and wherein each of said third portions intersects with the plane of the lower platform.
18. The hoist system of claim 15, wherein the remote end of each flexible member is secured so as to form two spaced apart portions that are in tension.
19. The hoist system of claim 1, wherein each support arm includes an actuator coupled thereto to adjust a length of the corresponding support arm, and wherein connection of the lower platform to the upper platform with the flexible members is configured such that extension of all of the support arms increases a height of the lower platform when the hoists fully retract the associated flexible members, wherein the controller operably is coupled to each of the actuators.
20. The hoist system of claim 15, wherein each couple comprises a third portion of the flexible member extending between the associated pulley of the first set of pulleys and the associated pulley of the second set of pulleys; wherein the plurality of support arms extend equally and radially from the rotational axis extending between the upper and lower platforms, the support arms being mounted to the upper platform to move therewith; and wherein each of the flexible members extends downwardly to the lower platform and also toward the rotational axis.
21. The hoist system of claim 15 wherein the support arms are adjustable in length and are mounted to the upper platform to move therewith, wherein each support arm includes an actuator coupled thereto to adjust a length of the corresponding support arm and wherein one of the hoists is mounted on each support arm; and wherein connection of the lower platform to the upper platform with the flexible members is configured such that extension of all of the support arms increases a height of the lower platform when the hoists fully retract the associated flexible members.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
(21) The embodiments described below and illustrated in the accompanying figures describe various inventive aspects for hoist systems. Although these aspects may be described and illustrated with respect to certain embodiments, it should be understood that these aspects can be combined in any manner or used alone in such hoist systems as desired and should not be limited to the specific embodiments herein provided.
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(24) The upper platform 104 supports the lower platform 102 (shown and labeled in
(25) The carriage 106 of the upper platform 104 optionally has trolleys 105 that slide linearly in the support structure 101. This allows the upper platform 104 to be able to move relative to the support structure 101. Additionally, the support platform 108 of the carriage 106 can be rotatable relative to portion 107 of the carriage 106 using rollers, bearings, guide surfaces or the like. Bearings can include fluid films (e.g. air or liquid) if desired. Likewise, magnetic bearings may also be employed. In the embodiment illustrated, rollers or wheel assemblies 131 are provided and fixed relative to one portion of the carriage, herein portion 107, while the rollers or wheels of assemblies 131 engage a surface(s) of the support platform 108. One or more drive motors 133 are illustratively provided for the wheel assemblies 131. Again, this embodiment is merely exemplary.
(26) The foregoing features taken alone or in combination may advantageously increase a work envelope of the lower platform 102. For instance, referring back to
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(29) Besides extending and retracting the support arms 112 so as to position the lower platform 102 where desired, it should also be noted that extension and retraction of the support arms 112 can be controlled for other purposes. For instance, stiffness of the upper platform 104 with the support arms 112 retracted is typically greater than when the support arms 112 are extended, for example, when lifting loads vertically. Relative stiffness of the upper platform 104, or of the system as a whole, can be determined or calculated and stored, for example, in computer memory. When it is desired to lift a load, or otherwise move a load within the work envelope with a desired amount of stiffness, such inputs can be provided to the system, for example, through a computer interface or the like wherein the system then extends or retracts the support arms 112 in order to obtain the desired stiffness.
(30) Another example of automatic extension or retraction of the support arms 112 occurs when it is desired to move the lower platform 102 (shown and labeled in
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(34) In some embodiments, hoist systems may include a system for ascertaining elongation of the wire rope(s) 115 due to the load on the lower platform 102. In this manner, compensation can be provided so as to position the lower platform 102 in a selected position, compensating for elongation in the wire rope(s) 115, compensating for slack in the wire rope(s) 115 and/or other external forces applied to the lower platform 102 and/or wire ropes(s) 115 in one, some or all degrees of freedom. In one embodiment, elongation or slack of a wire rope is measured directly with a sensor or sensors, for example, where the sensors are operably coupled between the upper platform 104 and the lower platform 102 along one, some or all of the wire ropes 115. Referring to
(35) Alternatively, or in addition, elongation of the wire rope can be ascertained by the amount of tension in the wire rope(s) 115. Tension in the wire rope(s) 115 can be measured using a load cell operably coupled to the wire rope 115 to sense tension therein. For instance, the load cell can couple an end of the wire rope 115 to the lower platform 102 again at 152. In another embodiment, a load cell can be incorporated in the mount for each hoist 113. In yet another embodiment, tension can be inferred through the work performed by the hoist(s) 113 for example by sensing characteristics of the power needed to operate the hoist such as the current for an electrical motor used to rotate a drum of the hoist, or fluid flow characteristics for a hydraulic or pneumatically powered hoist.
(36) The system can null out the effects of elongation of the wire rope(s) 115 in order to accurately position the lower platform 102 as desired. However, in addition, the system can also null out any other forms of deflection that may occur due to deflections or the like in other components such as but not limited to support arms 112, upper platform 104, lower platform 102, bridges, rails or components thereof to name just a few. Sensor(s) can be configured to provide signal(s) corresponding to deflections of one or more of these components. For instance, such deflections can be measured by displacement sensors, strain gauges to name just a few.
(37) Movement of the lower platform 102 to desired locations can be performed manually where the operator is given independent control of all hoist motors and/or drive motors to rotate the upper platform. Typically, the operator is provided with a user interface having one or more joysticks or other control mechanism where movements thereof are translated so as to operate the hoist motors 113 and/or drive motors to cause movement of the upper platform 104 or carriage 106 either directly through rotation thereof, movement of its trolley, and/or movement of a bridge supporting the carriage 106, if one is provided. Depending upon the location of the lower platform 102 relative to any obstacles in structure 120 such as the enclosure walls, the system can be programmed so as to automatically extend or retract one or more of the support arms 112 and/or rotate the upper platform 104 in order to avoid contact of the wire ropes 115 and/or the lower platform 102 with the enclosure 120 or other obstacles. The work envelope and any potential obstacles can be defined in computer memory wherein the position of the lower platform 102, wire ropes 115 and/or upper platform 104/carriage 106 can be tracked virtually in order to avoid contact with obstacles such as the enclosure walls. If desired, sensors can also be mounted to any of the components in the system such as the upper platform 104, lower platform 102, support arms 112 and/or mechanisms coupled to the lower platform 102. Such sensors can be proximity sensors so as to sense contact or possible contact of components of the system with obstacles and/or otherwise control the system to avoid such obstacles. In one embodiment, a system controller 160 (shown and labeled in
(38) As indicated above, in addition or in the alternative to monitoring elongation of wire rope(s) 115, the sensors to directly or indirectly sense tension in the wire rope(s) 115 can be configured so as to detect slack such as but not limited to if the lower platform 102 were to encounter an obstacle. If slack is detected in one or more wire ropes 115 via the sensor(s), the system controller 160 can be configured to provide an alarm and/or automatically operate the appropriate hoist(s) 113 until proper tension is obtained. If desired, the system controller 160 can be further configured to prevent other motions of the lower platform 102, which can include preventing further operation of the hoists 113, drive(s) 133, the drive mechanisms for the support arms 112 (e.g. actuators 144), drive(s) for the trolley 105 and/or drive(s) for a bridge on rails, the bridge supporting the trolley 105.
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(45) In the illustrated embodiment, the pulleys of the first set 312A-F are regularly closer together than the pulleys of the second set 310A-F. As indicated above, pulleys from the first set 312A-F and pulleys from the second set 310A-F are organized in pairs. Use of the spine assembly 304 so as to provide spaced-apart pulleys for each of the wire ropes 308A-308F in effect provides a couple using the wire ropes 308A-308F which can provide increased fidelity of control during movements of the lower platform 102, and in particular, angular movements (i.e., pitch, yaw and/or roll of the lower platform 102 with respect to a three orthogonal axes). In addition, the spine assembly 304 provides improved stiffness of the hoist system 300, particularly stiffness or rigidity to moments of angular movements (pitch, yaw and/or roll) of the lower platform 102. These benefits are realized due to the couple that is formed on the lower platform 102 by the set of two spaced apart pulleys 310A-310F and 312A-312F, respectively, provided for each wire rope 308A-308F.
(46) It should be noted that each of the pulleys of the first set 312A-F, the second set 310A-F and pulleys 314A-F on the upper platform 104 (shown and labeled in
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(49) Generally, the benefits discussed above with respect to hoist system 400 are believed also realized in hoist system 500 illustrated in
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(52) Various parameters of the hoist systems 100, 200, 300, 400, 500, and 600 can be adjusted (or are monitored or sensed in order to provide accurate positioning of the lower platform 102) depending on the specific application to which it is intended. Using by way of example hoist system 300,
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(54) Collar system 700 illustratively includes a spine or partial spine 702, a collar 704, and spine cables 706A-C. In an embodiment, spine 702 is a rigid or flex resistant member such as, but not limited to, a rod. The collar 704 can have sufficient mass so as to have weight (i.e. weighted collar) to cause tension in the wire ropes 706A-C used to position the collar 704 on the spine and where the collar 704 slides freely on spine 702. The spine 702 is attached to lower platform 102 such that movement of either spine 702 or platform 102 is translated to the other member.
(55) Weighted collar 704 is illustratively moved in a manner to track the motion of lower portion 102. For example, if the lower portion 102 is moved up a certain distance, weighted collar 704 is moved up approximately the same distance and at approximately the same rate. Embodiments are not limited to any particular method of moving weighted collar 704. In one embodiment, one or more hoists or reels are connected to collar 704 utilizing one or more spine cables. In the specific example shown in
(56) In one embodiment, the weighted collar 704 has a cylindrical inner aperture that fits around the spine 702. The spine 702 is able to move freely up and down along the y-axis shown in coordinate system 710, and is able to rotate freely about the y-axis in the direction shown by arrow 711 in
(57) In another embodiment, the spine 702 and the collar 704 are shaped such that they are keyed to each other. For instance, in one embodiment, the spine 702 has a rectangular shape, and the collar 704 has a rectangular aperture that the spine fits within. In such a case, in addition to reducing rotation about the x- and z-axes, 712 and 713, the system also helps to reduce rotation 711 about the y-axis.
(58) As was previously mentioned, in an embodiment, collar 704 allows for spine 702 to move longitudinally (i.e. along the y-axis shown by coordinate system 710). This helps to ensure that an appropriate amount of tension is maintained in the spine cable or cables even if there is some discrepancy in the tracking of collar 704 to lower portion 102. Accordingly, the collar system 700 may help to reduce tilting even if there is less than perfect tracking of movement between collar 704 and lower portion 102.
(59) The system controller 160 shown in
(60) The computer 170 comprises a conventional computer having a central processing unit (CPU) 172, memory 174 and a system bus 176, which couples various system components, including memory 174 to the CPU 172. The system bus 176 may be any of several types of bus structures including a memory bus or a memory controller, a peripheral bus, and a local bus using any of a variety of bus architectures. The memory 174 includes read only memory (ROM) and random access memory (RAM). A basic input/output (BIOS) containing the basic routine that helps to transfer information between elements within the computer 170, such as during start-up, is stored in ROM. Storage devices 178, such as a hard disk, a floppy disk drive, an optical disk drive, etc., are coupled to the system bus 176 and are used for storage of programs and data. It should be appreciated by those skilled in the art that other types of computer readable media that are accessible by a computer, such as magnetic cassettes, flash memory cards, digital video disks, random access memories, read only memories, and the like, may also be used as storage devices. Commonly, programs are loaded into memory 174 from at least one of the storage devices 178 with or without accompanying data.
(61) Input devices such as a keyboard 80 and/or pointing device (e.g. mouse, joystick(s)) 82, or the like, allow the user to provide commands to the computer 170. A monitor 184 or other type of output device can be further connected to the system bus 176 via a suitable interface and can provide feedback to the user. If the monitor 184 is a touch screen, the pointing device 182 can be incorporated therewith. The monitor 184 and input pointing device 182 such as mouse together with corresponding software drivers can form a graphical user interface (GUI) 186 for computer 170. Interfaces 88 on the system controller 60 allow communication to other computer systems if necessary. Interfaces 88 also represent circuitry used to send signals to or receive signals from the actuators and/or sensing devices mentioned above. Commonly, such circuitry comprises digital-to-analog (D/A) and analog-to-digital (A/D) converters as is well known in the art.
(62) Although the subject matter has been described in language directed to specific environments, structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not limited to the environments, specific features or acts described above as has been held by the courts. Rather, the environments, specific features and acts described above are disclosed as example forms of implementing the claims.