Relocatable fine motion positioner assembly on an overhead crane

A method and apparatus is provided for at least holding an object with a crane having a bridge spanning between and movable on the spaced apart rails, an upper platform movable longitudinally on the bridge, and a hoist mounted to the platform, the hoist having a rope and a lifting member disposed at a remote end of the rope. The method includes engaging and moving a positioner to a selected location on the bridge or the upper platform using the hoist; securing the positioner to the bridge at the selected location or the upper platform; securing the positioner to an object; holding the object with the positioner; releasing the object from the positioner; releasing the positioner from the bridge or the upper platform; and engaging and moving the positioner away from the selected location on the bridge or the upper platform using the hoist.

BACKGROUND

Overhead cranes are well known and are used frequently to lift and carry objects from one portion of a work bay to another. The crane commonly employs a single hoist that provides a lifting hook or other fixture used to carry the object. At least one and in some cases a plurality of vertically extending wire ropes support the lifting fixture where sheaves provided on the lifting fixture and proximate the hoist can be used to increase lifting capacity of the crane.

Although such cranes are well suited for lifting and carrying objects, such cranes do not allow accurate positioning of the object without help from additional devices or human operators since the wire rope(s) extend vertically. Performing work on the object when supported by the crane is typically not practical because the vertically extending wire rope(s) provide little if any ability to resist lateral loads and/or overturning moments such as a moment about the vertically extending wire rope(s), or about other axes orthogonal to the wire rope(s) depending upon the point of attachment to the object.

SUMMARY

The aspects described below are to various inventive aspects of a detachable and relocatable positioner on an overhead crane as well as a crane assembly including the same, and a method of operation regarding the same. These aspects need not be present on every system, or method but rather can be combined in any manner or used alone as desired.

A first aspect comprises a crane system having a pair of opposed rails and a bridge spanning between and supported on the rails and movable thereon. An upper platform is movable longitudinally on the bridge and carries a hoist. The hoist includes a rope and a lifting member disposed at a remote end of the rope. The crane system further includes a positioner. The positioner includes a frame with a lift point selectively engageable by the lifting member. A reference vertical axis extends through the frame. A plurality of hoists is mounted to the frame. Each hoist has at least one rope. The ropes from the hoists extend downwardly and inwardly to the vertical axis from spaced apart locations about the frame. The ropes are joined to and support a lower member at spaced apart locations about the lower member. One or more locking devices are configured to selectively secure the positioner to at least one of the upper platform or the bridge.

The crane system can include one or more of the following features. In particular, the one or more locking devices can be configured to completely detach the positioner from the bridge or the upper platform, or detach in a manner so that the positioner can be moved to a different location on the bridge while remaining in contact with and being supported by at least in part by the bridge.

If desired the positioner and the bridge or upper platform can include one or more contact or non-contacting aligning devices comprising a first element disposed on the bridge or upper platform and a second element on the frame that is alignable with the first element and configured to locate a fixed position for the positioner on the bridge or upper platform. In a further embodiment, a plurality of spaced apart first elements can be disposed on the bridge or upper platform each alignable with the second element on the frame.

In one embodiment, the lift point is at least proximate a center of gravity for the positioner and is configured to be moved away from the center of gravity to allow the lift member to extend downwardly through a recess in the frame of the positioner. The recess can comprise an upper channel also of size to receive the lift member. The upper channel includes an opening at a location on an outer perimeter of the frame. The opening of the upper channel is oriented such that the rope can traverse the channel with movement of the hoist on the bridge, while the rope extends through the positioner. Likewise, the lower member can include a lower channel that is aligned with the upper channel allowing the rope and lifting member to extend through the lower channel.

The locking devices can comprise a clamp or other suitable fastener. The locking devices can engage a lower horizontal flange on the bridge or upper platform such as the opposed horizontally extending flanges on an I-beam or support plate. However, on other bridges or portions of the upper platform such as those formed as an elongated box section, support(s) and/or other modifications, for example, aperture(s) can be formed on the bridge or upper platform to which the positioner can be attached when desired. If desired, the support(s) can extend continuously along the longitudinal length of the bridge.

A fixture can be provided and configured to hold the positioner when in storage. The fixture can be located in a position or be movable to a position such that the lifting member of the hoist engages the lift point on the frame.

Another aspect is a method for at least holding an object with a crane having a bridge spanning between and movable on the spaced apart rails, an upper platform movable longitudinally on the bridge, and a hoist mounted to the platform, the hoist having a rope and a lifting member disposed at a remote end of the rope. The method includes engaging and moving a positioner to a selected location on the bridge or the upper platform using the hoist. For the inventive method, the positioner need not be of the type described above, but in an advantageous embodiment can be. The positioner is secured to the bridge at the selected location or the upper platform. The positioner can then be secured or otherwise fastened to an object at which point the positioner can be used to hold the object with the positioner for purposes such as fabrication, assembly and/or inspection. The positioner can also be used to accurately position the object as desired.

Upon completion of the task with the object, the object is released from the positioner and the hoist engages the positioner. Typically, the positioner is then released from the bridge or upper platform such that the hoist can move the positioner away from the selected location on the bridge or the upper platform.

The method can further include holding the positioner in a fixture spaced apart from the bridge prior to engaging and moving the positioner to the selected location on the bridge or upper platform, and wherein engaging and moving the positioner to the selected location or upper platform includes lifting the positioner with the hoist from the fixture, and wherein moving the positioner away from the selected location on the bridge or upper platform includes lowering the positioner on the fixture, and wherein the method further comprises releasing the positioner from the hoist.

If desired, the positioner and the bridge or upper platform can include one or more aligning devices comprising a first element disposed on the bridge or upper platform and a second element on the frame that is alignable with the first element at the selected location, and wherein engaging and moving a positioner to a selected location on the bridge or upper platform using the hoist includes moving the positioner until the first and second elements are aligned.

The method can further include lifting an object with the hoist and moving the object to a position below the positioner when the positioner is secured to the bridge at the selected location. In one embodiment, the positioner includes a channel having an opening and wherein moving the object to a position below the positioner when the positioner is secured to the bridge at the selected location includes moving the rope through the channel and through an opening provided on an outer perimeter edge of the positioner. In yet a further embodiment, moving the object includes moving the upper platform to a position above the positioner.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENT

The embodiment described below and illustrated in the accompanying figures describe various inventive aspects of a detachable and relocatable positioner on an overhead crane as well as a crane assembly including the same, and a method of operation regarding the same. Although these aspects are described and in illustrated with respect to the exemplary embodiment, it should be understood that all the aspects need not be present on every system, but rather can be combined in any manner or used alone as desired.

Referring to the figures, an overhead crane is illustrated at10and in the embodiment illustrated comprises a gantry crane having a bridge12moveable on opposed rails14. A hoist16is mounted to an upper platform18that in turn is selectively positionable on the bridge12thereby creating a work envelope19extending between and along the rails14and with a height equal to the distance of lift provided by the hoist16. Although the crane system10is well suited for carrying and lifting objects, such cranes are unable to position, orient and/or hold the object with precision necessary for some fabricating and/or assembly needs.

A relocatable and/or detachable positioner is illustrated at24. Generally, the positioner24is moveable to a desired position on the bridge12by the hoist16and the upper platform18. After obtaining the desired position on the bridge12, the positioner24is secured to the bridge12or the hoist16(e.g. upper platform18), but in a releasable manner. In an embodiment where the positioner24is secured to the bridge12, after securing the positioner24to the bridge12, the hoist16can be detached from the positioner24and used, for example, to lift and carry objects in at least some of the work envelope19, and in an a particularly advantageous embodiment, to lift and carry an object to a position below the positioner12where the positioner24can then be attached to the object and be used to accurately position, orient and/or securely hold the object as needed.

In a first illustrated embodiment, the bridge12includes two parallel support members30,32upon which the upper platform18can be guided on for example using linear bearings or other suitable guides. Likewise, the bridge12can be guided on each of the support rails14with linear bearings or other suitable guides. Movement of the platform18on the bridge12as well as the bridge12upon the rails14is all that is needed for understanding aspects of the present invention. Mechanisms for accomplishing such movements (e.g. hydraulic and/or electric motors carried by the bridge12or platform18engaging linear gear racks on the rails14and bridge12) are well known to those skilled in the art and can take any number of forms. It should also be noted that the bridge12need not comprise two parallel support members30,32wherein a single support member spanning between the rails14may be sufficient in some embodiments.

Referring toFIG. 2, in one embodiment, the positioner24can be held in a holding fixture35when not in use. When it is desired to mount the positioner24to the bridge12or the hoist16, the crane10is operated so as to position a lifting member such as a carrying hook34or the like of the hoist16over the positioner24. It should be noted that the holding fixture35can be located in a stationary position, or if desired, can include wheels36so as to allow the positioner24/holding fixture35to be located at a convenient location for attachment to the hoist16and then returned to another location for storage when not in use.

FIGS. 4 and 10illustrates attachment of the carrying hook34to the positioner24. In the illustrated embodiment, the positioner24includes a standoff38on a frame40to form a lift point. For example, the standoff38can include a suitable aperture for receiving the carrying hook34; however, it should be understood that this is but one embodiment for illustrating connection of the hoist16to the positioner24and as appreciated by those skilled in the art other forms of lift points and/or attachment mechanisms can be used.

It should be also noted that, if desired, the positioner24can be stored in a selected location on the bridge12, for example, at one end when not in use. When it is desired to use the positioner24, the hoist16can move the positioner24along the bridge12to the selected location being connected to the hoist34by the carrying hook34or being connected to another portion of the hoist16such as upper platform18(and back to the storage location on the bridge12), and if desired, without the positioner24ever being fully detached from the bridge12.

FIG. 6illustrates attachment of the positioner24to the bridge12at a selected location. The positioner24and the bridge12include one or more locking devices44(FIG. 2) with complimentary elements so as to releasably secure the positioner24to the bridge12. By way of example, each support member30,32of the bridge12can comprise an I-beam, the I-beam having horizontal flanges33formed on a lower surface thereof extending in opposite directions. In this embodiment, the positioner12includes a plurality of locking devices44. Each locking device comprise a clamp that has elements that engage and clamp to the horizontal flanges33of the support members30,32and thus holds the positioner12in a fixed position. In the embodiment illustrated, the positioner24includes three spaced apart locking devices44for each of the support members30,32. However, this is but one embodiment in that any desired number of locking devices can be used depending, for example, upon the application. Likewise, in yet another alternative embodiment, the locking device can comprise a movable member such as a rod or wedge with a complementary member, for example, an aperture or other form of receiver to secure the positioner24to the bridge12.

Although illustrated wherein the bridge includes I-beam support members, this is but one embodiment. For instance, bridges can be formed as an elongated box section. In such cases, it may be necessary to include apertures and/or structures welded or otherwise joined to the bridge12. Generally, the bridge12is of a shape that includes or is modified to include (such as on existing crane systems) locations capable of supporting the positioner24in a fixed position to which the positioner24is secured to.

In a further embodiment, the positioner24and the bridge12can have complimentary elements so as to align the positioner24and secure the positioner24in a predetermined location. Such aligning elements can be contacting or non-contacting. For instance, the positioner24can have standoffs or projections43extending from a surface of the bridge12wherein the positioner24includes a receiver47that receives the standoff or projection43. In a further embodiment, a plurality of spaced apart complimentary aligning elements are provided on the bridge12and positioner24so as to ensure a desired orientation of the positioner24on the bridge12. It should also be noted, the aligning members (as illustrated by projections43) on the bridge12can be spaced apart along the bridge12so that the positioner24can be secured at any one of a number of different locations on the bridge12. Non-contacting aligning members can take the form of positioner sensors that provide an output signal indicating that the positioner24is in a desired position. Likewise, a camera referencing a fixed scale can also be used.

FIG. 11illustrates another embodiment where the positioner24is secured to the hoist16so as to move therewith on the bridge12when connected thereto. In this exemplary embodiment, the upper platform18includes support plates17to which the positioner24is selectively secured. In this illustrative embodiment, each of the support plates17have opposed horizontal flanges37formed on a lower surface thereof extending in opposite directions similar to the flanges33described above. Locking devices44clamp to the flanges37in the same manner, being suitably disposed on the positioner24to align with the flanges37. Similarly, if desired, the positioner24can align to standoffs or projections (similar to projections43) extending from a surface of the support plates17wherein the positioner24includes a receiver (similar to receiver47) that receives the standoff or projection43. In a further embodiment, a plurality of spaced apart complimentary aligning elements are provided on the support plates17and positioner24so as to ensure a desired orientation of the positioner24on the hoist16. Non-contacting aligning members can take the form of positioner sensors that provide an output signal indicating that the positioner24is in a desired position. Likewise, a camera referencing a fixed scale can also be used.

It should be understood that the support plates17illustrated inFIG. 11are merely exemplary. In another embodiment, the support plates17can be located between the rails of the bridge12rather than on the outside thereof. As appreciated by those skilled in the art, the support plate(s) of the hoist16to which the positioner24is selectively secured can take any number of forms. Likewise, the locking devices44can take any number of forms as discussed above. In addition, separate locking devices44can be provided to attach the positioner24selectively to either the upper platform18or the bridge12, or the locking devices44can be selectively configured in a movable manner to engage the upper platform18or the bridge12as desired.

Referring now to aspects of the positioner24, as stated earlier, the frame40includes a lift point38selectively engageable by the lifting member34. Typically, the lift point38is disposed on the positioner24at or at least proximate to the center of gravity of the positioner24. A reference axis50can be defined as extending downwardly, for instance, through the center of gravity. A plurality of hoists55each hoist55having at least one rope51where the ropes51extend downwardly and inwardly to the axis50from spaced apart locations about the frame40. The ropes51are joined to a lower member52at spaced apart locations about the lower member52. With this construction, the lower member52to at least some lateral forces and/or moments is obtained because the wire ropes51are kinematically constrained and where the stiffness of the lower member52is determined at least in part, by orientation of the ropes51relative to each other and the tensile elasticity of the ropes51. The lower member52can be moved in a work envelope indicated by circle58as determined by the length of each of the wire ropes51suspending the lower member52from the frame40. In the illustrative embodiment, six wire ropes51are used. Both the frame40and the lower member52each have three spaced apart locations where two wire ropes51are joined or substantially come together such that the wire ropes51at each location come from two different locations on the lower member52/support frame40. With the plurality of ropes so arranged the positioner24can pick up and lift offset loads since the positioner can resist overturning moments to some extent, if desired. The positioner of this type can take a number of different forms or include other features. Some exemplary embodiments of such a positioner are disclosed in WO 2011/123816, the content of which is hereby incorporated by reference in its entirety. Operation of the hoists of the positioner can be performed with a wireless or tethered communication.

Although not shown, the lower member52includes support(s), hook(s), fastener(s) and the like to connect the object thereto, the specific details of which are not pertinent to the present invention and vary depending upon the object.

Referring to FIG., the frame40includes frame members63that create at least an aperture60through which the lifting member34can extend through when the hoist16is above the positioner24. In this manner, the hoist16can be used to pick up an object while the positioner24is in place. In such situations, the lower member52is moved away, removed and/or includes a similar aperture such that the lifting member34can engage the object.

In yet a more advantageous embodiment, the frame members63define an upper channel67leading to the aperture60from an opening68at a location on an outer perimeter of the frame40. The opening68of the channel67is aligned with linear movement of the rope of the hoist16as the platform18moves the hoist16along the bridge12. The opening68thus allows the rope to enter the channel67, while the channel67is of sufficient length to allow the rope to be positioned easily below the positioner24to pick up or release objects.

In yet a further advantageous embodiment, the lower member52also includes a channel69that serves the same purpose as the upper channel67, that being allowing the rope to be moved linearly therein with movement of the hoist16on the bridge12. As such, the channel69in the lower member52is aligned with the upper channel67, each of which can have a width to accommodate the lifting member34if disposed therethrough.

By allowing the lifting member34and wire rope of the hoist16to extend through the positioner24and in particularly through the frame40having the channel67and the lower member52having the channel69, objects can be picked up by the hoist16with movement of the bridge12upon the rails14and the platform18on the bridge12and then moved to be placed below the positioner24. At which point, the hoist16, if desired, can be detached from the object with the hook34and the wire rope pulled upwardly through the apertures of the lower platform52and the frame40. It should be noted that the positioner24can be secured to the bridge12such that the channels67,69open in either direction with respect to being parallel to the bridge12to allow the rope to be moved therein.

Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above as has been determined by the courts. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.