System and method for connecting a crane suspension assembly to a support column

An intermediate suspension connection column segment designed for use in constructing a column which is supported by a suspension that includes a first end having a first connection configured to connect to a first adjacent column segment; a second end opposite the first end, the second end having a second connection configured to connect to a second adjacent column segment; and an intermediate suspension connection between the first connection and the second connection, the intermediate suspension connection configured to couple an intermediate suspension between the suspension and the column.

BACKGROUND

The present invention relates to systems and methods for connecting a crane suspension assembly to a support column on a crane. More particularly the present invention relates to systems and method for connecting a pendant to an intermediate location on a crane boom.

Lift cranes typically include a carbody; ground engaging members elevating the carbody off the ground; a rotating bed rotatably connected to the carbody such that the rotating bed can swing with respect to the ground engaging members; and a boom pivotally mounted on the rotating bed, with a load hoist line extending there from. For mobile lift cranes, there are different types of moveable ground engaging members, most notably tires for truck mounted cranes, and crawlers. Typically mobile lift cranes include a counterweight to help balance the crane when the crane lifts a load. Typical cranes include a boom suspension that is used to change the angle of the boom and provide tension forces to offset the forces applied to the boom by the load on the load hoist line so that the boom can behave as a column member with only compressive forces acting through the length of the boom.

Typical cranes are designed to be set up with different boom length configurations to optimize the capacity that the crane can handle, only using as long of a boom as is necessary for a particular lift operation that the crane is being set up for. Since the boom length will vary between different configurations, the boom suspension also has to be designed to accommodate different boom lengths. Typically the boom suspension includes multiple sections of suspension members that are connected together, sometimes referred to as boom backstay straps, which connect between the top of the boom and either an equalizer suspended between the boom and a fixed mast, or between the boom and the top of a live mast. The suspension member may be rigid such as steel bars or may be flexible such as wire or synthetic rope. On a crane with a relatively long boom, the suspension may additionally be connected to the boom at an intermediate location less than the top of the boom. On a typical crane with a fixed mast, the boom hoist rigging has multiple parts of line that run between the equalizer and the top of the mast, and is used to control the angle of the boom.

Since the crane will be used in various locations, it needs to be designed so that it can be transported from one job site to the next. This usually requires that the crane be dismantled into components that are of a size and weight that they can be transported by truck within highway transportation limits. The ease with which the crane can be dismantled and set up has an impact on the total cost of using the crane. Thus, to the extent that fewer man-hours are needed to set up the crane, there is a direct advantage to the crane owner or renter.

It is convenient to transport the sections of the boom straps and jib backstay straps with the sections of boom between one job site and the next. This is because, for the most part, the number of sections and the length of each section of the boom straps and the jib backstay straps that will be needed are dependent on the number and lengths of the boom sections that are used to construct the boom. For example, a 100 foot boom may be made from a 10 foot boom butt, a 10 foot boom top and four 20 foot boom inserts. However, if the boom is going to be 120 feet long, five 20 foot boom inserts will be used. If the boom is going to be 130 feet long, five 20 foot inserts and one 10 foot insert will be used.

A typical boom insert has connectors at each end for connection to an adjacent crane section. The connectors are typically tabs having an aperture for receiving a pin. A boom insert may have complementary connectors at each end of the boom insert. For example, a near end of the boom insert may have single tabs with an aperture. A far end of the boom insert may use sets of tabs spaced apart by the thickness of the tab on the first end. Thus when the boom inserts are placed together end to end, the single tab of the first end may be orientated between the two tabs of the second end with their apertures aligned. A pin is then inserted through the apertures coupling the boom inserts together. To aid in alignment of the boom inserts during assembly, the tabs on an upper side of a boom insert may be replaced by bracket and pin. The far end of the boom insert may have a bracket on the upper side with the bracket opening upward. The near end of the boom insert may have a horizontal pin complementary to the bracket. Two boom connections may then be assembled by joining the bracket and pin with the boom inserts angled relative to one another. Then, with the pin in the bracket, the boom insert is rotated until the tabs on the lower section are aligned. A pin is then inserted into the aperture of the tabs and the boom sections are coupled together.

When an intermediate suspension connection to the suspension is required, an intermediate suspension connector such as a pendant assembly is used to join the suspension to the boom. The pendant assembly connects to the boom at the connection between adjacent boom inserts. Typically, the lower pins are replaced by longer pins. The pendant assembly has tabs on its lower end that are spaced apart the width of the outer tabs of the boom insert. Thus when the boom is assembled, the boom inserts are coupled together as described previous with the exception that the pendant assembly is placed over the tabs of the boom insert. Apertures in the pendant tabs are aligned with the apertures in the boom insert tabs and the longer pin is inserted through the pendant tabs and the boom insert's tabs. The longer pin couples the boom inserts together along with the pendant assembly.

The described system of attaching a pendant assembly to a boom is advantageous in that it requires no special parts other than the pendant assembly and the longer pins. If the pendants assembly is not required, it is simply not attached between boom sections. However, assembly of the crane sections is complicated by the additional alignment necessary with the pendant assembly. Also, because the pendant assembly is a separate component, there exists the possibility that the pendant assembly may be lost or unavailable when assembling the boom. The assembly of the boom cannot be completed until the pendant is in place. Therefore there would be a great benefit if it were possible to attach the boom to the suspension using a method that did not require a pendent coupled to the ends of a boom. Further, by simplifying the connection of the boom inserts when a pendant is required, the amount of time it takes to assemble a boom may be shortened and potential delays reduced.

BRIEF SUMMARY

Embodiments of the invention are directed to an intermediate suspension connection column segment for use in constructing a column which is supported by a suspension. The segment includes a first end having a first connection configured to connect to a first adjacent column segment and a second end opposite the first end with the second end having a second connection configured to connect to a second adjacent column segment. An intermediate suspension connection is disposed between the first connection and the second connection with the intermediate suspension connection configured to couple an intermediate suspension between the suspension and the column.

In another embodiment of the invention a column assembly includes a plurality of column segments coupled end to end with at least one column segment being the described intermediate suspension connection column segment. A suspension is attached to the column adjacent the top of the column.

In another embodiment of the invention, a crane has a column formed of a plurality of column segments coupled end to end with at least one column segment being the previously described intermediate suspension connection column segment. A mast extends laterally from the column and a plurality of suspension members couple the mast to an end of the column. At least one pendant is connected to the intermediate suspension connection and at least two suspension members from among the plurality of suspension members.

Embodiments of the invention are further directed to a method for erecting a crane. In the method at least three boom segments are assembled end to end. At least one of the boom segments has an intermediate suspension connection between the ends of the segment. The at least boom segments are coupled end to end to form a column assembly. A first end of the column assembly is coupled to a pivot point. A plurality of suspension members is coupled end to end to form a suspension to connect a second end of the column assembly to a mast. An intermediate connector is coupled to the intermediate suspension connection point and to at least two suspension members from among the plurality of suspension members. The suspension members are then tensioned to lift the second end of the column assembly.

The following terms used in the specification and claims have a meaning defined as follows.

The term “crane suspension assembly section” refers to sections that are connected together to form a suspension assembly for a crane. Examples of crane suspension assembly sections include a) sections, sometimes called strap sections, of the backstay between the boom top and the equalizer or live mast; b) sections of the backstay between a boom butt and a jib strut; c) sections of the backstay between a jib strut and a jib top, and d) counterweight strap sections between a mast top and a counterweight. Besides strap sections, which are traditionally elongated rigid metal members with a head on each end with a hole there through, sometimes wire rope pendants, carbon fiber tension members, and synthetic fiber members are used to create the longitudinal part of the crane suspension assembly, and are therefore crane suspension assembly sections. The sections may be made of multiple parallel elongated members. The term “crane suspension assembly section” also includes the equalizer and the boom top, since these are parts of the boom suspension assembly and are connected to boom backstay straps. “Crane suspension assembly section” also includes other members attached to strap sections, such as the boom butt, the mast top, the jib top, jib strut tops and live mast top, and intermediate suspension members.

The term “pin” refers to a generally cylindrical member that allows pivotal rotation between two or more structures that have a hole through them and are connected together by the pin fitting through the holes. A pin may include a head or retainer, such as a cotter pin, on one or both ends to prevent the pin from sliding longitudinally through the holes. While most pins used in the present invention will have smooth shafts, a bolt with a threaded shaft may be used as a pin in some instances, and in such usages is therefore within the meaning of the term “pin.”

The term “connector plate” refers to a structure used to hold an elongated section of the crane suspension assembly to other sections of the assembly. Typically connectors have two holes through them so that they can be attached, with a pin through each hole, between two adjoining straps in the crane suspension assembly. A connector may have only one link plate. More typically the connector is made of multiple link plates so that it can sandwich the head of the strap between the link plates and thus transfer tension loads equally through the two link plates without inducing bending moments through the connector/strap section joint. When the straps to which the connectors are attached are made of multiple parallel elongated members, the connectors will often include a number of link plates one greater than the number of elongated members. For example, when the sections of the crane suspension system are made of two elongated members, the connector will be made with three link plates.

The term “tab” refers to an extension of material extending from a structure. A tab may be a separate component that is joined to the structure through commonly available techniques such as fasteners, welding, gluing or otherwise bonding. A “tab pair” refers to a pair of tabs that are used for a common purpose. For example, a tab pair may receive a component in a space between pair of tabs and both of the tabs may be used to secure the component.

While the invention will have applicability to many types of cranes, it will be described in connection with a mobile lift crane10, shown in an operational configuration with a live mast inFIG. 1and in an operational configuration with a fixed mast inFIG. 2. The mobile lift crane10includes lower works, also referred to as a carbody12, and moveable ground engaging members in the form of crawlers14. Of course additional crawlers than those shown can be used, as well as other types of ground engaging members, such as tires.

A rotating bed20is mounted to the carbody12with a slewing ring, such that the rotating bed20can swing about an axis with respect to the ground engaging members14. The rotating bed20supports a boom22pivotally mounted on a front portion of the rotating bed20; a live mast28mounted at its first end on the rotating bed20, boom hoist rigging30connected to the live mast28adjacent a second end of the live mast28; and a moveable counterweight unit34. The counterweight unit34may be in the form of multiple stacks of individual counterweight members on a support member.

Boom hoist rigging30(described in more detail below) between the top of the live mast28and the rotating bed is used to control the angle of the live mast28. A suspension assembly36between the top of the live mast28and the boom22supports the boom22. A load hoist line (not shown) is trained over a pulley on the boom22, supporting a hook (not shown) at a first end. At a second end, the load hoist line is wound on a first main load hoist drum connected to the rotating bed20. The rotating bed20includes other elements commonly found on a mobile lift crane10, such as an operator's cab and a hoist drum for the boom hoist rigging30.

The boom hoist rigging30includes a boom hoist line in the form of wire rope wound on a boom hoist drum, and reeved through sheaves on the live mast28. The live mast28is connected to the rotating bed20though the boom hoist rigging30and to the boom22through a suspension assembly36. This arrangement allows rotation of the boom hoist drum to change the amount of boom hoist line between the live mast28and the rotating bed20changing the mast angle and thereby changing the boom angle through the suspension assembly36.

As discussed above, the boom22is made by connecting multiple boom sections together and the boom22is supported during crane operation by the suspension assembly36made from boom strap sections. The top end of the suspension assembly36is connected to the top end of the boom22and an intermediate location of the suspension assembly36is connected to an intermediate location of the boom22through a pendant38. The boom22may connect to the suspension assembly36through multiple pendants38at different locations on the boom22.

FIG. 2illustrates the mobile lift crane ofFIG. 1having a fixed mast60in addition to the live mast28. The fixed mast60is connected to the boom22through suspension assembly62. The suspensions assembly62is connected to the boom22at the hoist end and at an intermediate location through a pendant64. The fixed mast60has a boom hoist line reeved between the fixed mast60and an equalizer66coupled to the suspension assembly62configured to adjust the distance between the fixed mast60and the hoist end of the boom22thereby adjusting the boom angle. The suspension assembly62is made up of the boom strap sections as described previously.

FIG. 3illustrates an embodiment of an intermediate suspension connection column segment in the form of a boom insert300. An intermediate suspension connection column segment may be used in other column structures such as jibs and masts and embodiments are not limited to booms. A column may be formed of multiple intermediate suspension connection column segments allowing the suspension assembly to connect to the column in multiple locations.

The boom insert300is made up of a lattice of structural elements302coupled to four longitudinal chords304,305,306,307. Other numbers of chords and different types of construction of an intermediate suspension connection column segment are possible and the embodiment ofFIG. 3is only given as an example. The four chords304,305,306,307are arranged in a rectangular pattern with an axis of each chord304,305,306,307arranged on a vertex of the rectangular pattern. The chords304,305,306,307are parallel to one another along their axes such that together they form a square column. The structural elements302are arranged diagonally along the sides of the boom insert300such as between chords304and305, chords305and306, chords306and307, and chords307and304. At each end of the boom insert300horizontal structural elements308,310,312,314and vertical structural elements316,318,320,322are arranged between the rods to form a rectangular end of the boom insert300.

A first end324of the boom insert300has a first connection270that includes a first tab326and a second tab328extending from the lower chords304,307of the boom insert300. Each tab326,328has a horizontal aperture330sized and shaped to receive a pin. The first connection270also includes a first hook332and a second hook334extend from the upper chords305,306of the first end324of the boom insert300. The first hook332and the second hook334open upward and are sized and shaped to receive a pin.

A second end336of the boom insert300opposite the first end324has a second connection290, such as four tab pairs338, with each tab pair338extending longitudinally from a chord304,305,306,307. The tab pairs338each have a first tab340and a second tab342spaced apart by a distance slightly greater than a width of the tabs326,328on the first end324. The tab pairs338each have an aperture344sized and shaped to receive a pin.

A lower cross member346is disposed between the first end324of the boom insert300and the second end336of the boom insert300. The lower cross member346extends from a first lower chord304horizontally to a second lower chord307. The lower cross member346may have additional structural supports348tying the lower cross member346into the boom insert300. An intermediate suspension connection290may include a first connector and a second connector disposed on an upper side of the lower cross member346. In the embodiment ofFIG. 3, the first connector and the second connector are tabs350, each having an aperture there through. The aperture provides a location for a pendant to attach to the lower cross member346.

Two upper cross members354,356are disposed on the upper chords305,306above the lower cross member346. As best illustrated inFIG. 11, the upper cross members354,356have a longitudinal spacing, or a space355, sufficient to allow a pendant to pass between them. The two upper cross members354,356may have additional structural members tying them into the boom insert300.

Pendant elements358,359,360,361may be stored within the lattice structure of the boom insert300. A first pair of pendants358,361has a first length for operating at a first boom length. A second pair of pendants359,361has a second length for operating at a second boom length. Additionally pairs of pendants are possible for additional boom lengths. The pairs of pendants may be secured within the boom insert300through conventional means such as clamps, straps, and fasteners.

FIG. 11illustrates the boom insert300ofFIG. 3with a box1100for storing pendants during transport of the boom insert300. The box1100has two tabs1104extending from a side of the box1100. The tabs1104have a distance between their outer faces that is less than the distance between the tabs350on the lower cross member346such that the tabs1104of the box1100fit between the tabs350of the lower cross member346. A pin may be inserted into the aperture of the lower cross member tabs350and into an aperture of the tabs1104of the box1100, thereby securing the box1100to the boom insert350. The box1100is divided into a series of compartments1108for storing a pendant. The pendants may be flexible such that they may be coiled and placed in a compartment1108of the box1100. The box1100shown inFIG. 11has 6 compartments1108, and each compartment1108may house a pair of pendants for a total of 6 different possible lengths. Or in some embodiments each compartment1108may hold a single pendant such that three pairs of pendants are stored in the box1100. Other quantities of compartments1108are possible and the storage of the pendants may be mixed, with some compartments1108holding a single pendant and other holding more than one pendant. A cover may be secured over the box1100to close the compartments1108holding the pendants. During use of the boom insert300, the box1100may be removed from the boom insert300.

A suspension assembly section362may be stored on the boom insert300. The suspension assembly section362includes a first strap assembly363and a second strap assembly364. Each of the strap assemblies363,364includes a first strap segment365, a second strap segment366, and a link or three-way connector367. A first end of the first strap segment365is coupled to the link or three-way connector367and a first end of the second strap segment366is coupled to the three-way connector367. A second end of the first strap segment365has a connector for connecting to an adjacent component. A second end of the second strap segment366has a connector for connecting to an adjacent component. The second ends of the strap segments365,366may be configured to connect directly to an adjacent strap, or they may be configured to connect to an adjacent strap through a connector plate. The strap assemblies363,364may be secured to the boom segment300for transportation and storage using commonly available techniques such as clamps, straps, and fasteners.

FIG. 5provides a detailed view of the strap segments363,364being connected to the three-way connector367. The first end of each strap segment363,364has an aperture sized and shaped to receive a pin. The three-way connector367has a thickness that is similar to a thickness of the strap segments363,364. Three apertures are disposed in the three-way connector367with each aperture sized and shaped to receive a pin. A pair of connector plates368,370is disposed about the first end of a strap segment363with an aperture372of the connector plates368,370aligning with the aperture of the strap segment363. A pin is inserted through the aperture372of the connector plates368,370and the aperture of the first end of the strap segment363, coupling the strap segment363to the connector plates368,370. The connector plates368,370are positioned on each side of the three-way connector367with a second aperture374of the connector plates aligned with an aperture of the three-way connector367. A pin is inserted through the aperture374of the connector plates368,370and through the aperture of the three-way connector367, coupling the connector plates368,370to the three-way connector367. The process is repeated for the remaining strap segment364such that two strap segments363,364are coupled to the three-way connector367. With the strap segments363,364coupled to the three-way connector367, the strap assembly363is ready to be used in a suspension assembly such as suspension assembly36and suspension assembly62.

FIG. 4illustrates a side view of an embodiment of the boom insert300ofFIG. 3having a pendant360coupled to the lower cross member346and to a strap assembly364.FIG. 5illustrates a detailed view of connection of the pendant360to the three-way connector367, whileFIG. 6illustrates a detailed view of the pendant360coupled to the tab350of the lower cross member346. In this embodiment the pendant360is a flexible rope tensioning member376. The flexible rope tensioning member376may be a wire rope, a carbon fiber rope, or other synthetic fiber rope. The flexible rope tensioning member376has a connector378at each end with a parallel tab pair380having an aperture382. The parallel tab pair380is spaced apart by a distance greater than a width of the tab350on the lower cross member346and the width of the three-way connector367.

As shown inFIG. 6, the connector378at the lower end of the pendant360is coupled to the lower cross member346by placing the tab pair380over the tab350of the lower cross member346such that the aperture of the tab pair380aligns with the aperture of the tab350of the lower cross member346. A pin is then inserted through the apertures coupling the pendant360to the lower cross member346.

As shown inFIG. 5, the upper end of the pendant360is coupled to the three-way connector367by placing a tab pair384of the upper connector386over the three-way connector367aligning the aperture of the tab pair384with an available aperture of the three-way connector367. A pin is then inserted though the apertures coupling the pendant360to the three-way connector367.

FIG. 7illustrates the boom insert300ofFIG. 4with the suspension assembly section362being coupled to the boom insert300through pendant360. The suspension assembly section362is shown elevated above the boom insert300with the pendant360being stretched between the suspension assembly section362and the boom insert300. The suspension assembly section362would be lifted from the boom insert300as shown inFIG. 7when a mobile crane lifts the boom. The suspension assembly section362lifts the boom insert300through the pendant360as the mobile crane lifts the boom. Different lengths of pendants may be used to adjust the height the suspension assembly section362may rise above the boom insert300before lifting the boom insert300. Typically when the boom insert300is used near the hoist end of the boom, a shorter pendant is used compared to the boom insert300being used farther from the hoist end of the boom.

FIG. 8illustrates the boom insert300ofFIG. 3with an alternative pendant assembly800. The pendant assembly800has two vertical posts802,804coupled by cross bracing806. A lower end of each vertical post802,804has a connector807for coupling to the lower crossbar346of the boom insert300. The connector807is a tab pair808spaced apart by at last the thickness of the tab350of the lower cross member346. The tab pair808has an aperture810sized and shaped to receive a pin. As shown inFIG. 9, in use the tab pair810is placed over the tab350of the lower cross member346such that the aperture810of the tab pair808is aligned with the aperture of the tab350of the lower cross member346. A pin is inserted through the apertures810to couple the pendant assembly800to the boom insert300.

Each of the vertical posts802,804has a longitudinal cavity disposed in an upper end of the post. The longitudinal cavity is sized and shaped to receive a post insert812in a slidable connection. A post insert812is disposed in the longitudinal cavity. A retention mechanism retains the post insert812within the longitudinal cavity. Thus the post insert812may move vertically within the longitudinal cavity, but the retention mechanism prevents the post insert812from leaving the longitudinal cavity completely. The retention mechanism may be a vertical slot814in the post insert812and a corresponding pin816extending from the vertical post802into the vertical slot814. In other embodiments the retention mechanism may be an enlarged lower portion of the post insert812and a narrowed upper portion of the post cavity, a mechanical interference preventing the post insert812from escaping the post cavity, or any other retention mechanism.

The post insert812has an upper end having a fastener for coupling to a strap assembly. In some embodiments the upper end may have a tab pair that function as previously described with relation to the flexible pendant upper connector384. In such embodiments the upper connector384would couple to the existing three-way connection367. In other embodiments the upper end of the post insert812may have two tabs818,820extending from the post insert812with each of the tabs818,820having an aperture822,824sized and shaped to receive a pin. In such embodiments the three-way connector is not necessary and the connection plates368,370are connected directly to the pendant assembly800by inserting a pin through the aperture of the connection plates368,370and the aperture822,824of a tab818,820on the post insert812.

FIG. 10illustrates the boom insert ofFIG. 3with the pendant assembly ofFIGS. 8 and 9. The suspension assembly section362is shown elevated above the boom insert300with the pendant assembly800being extended between the suspension assembly section362and the boom insert300. The suspension assembly section362would be lifted from the boom insert300as shown inFIG. 10when a mobile crane lifts the boom. The suspension assembly section362lifts the boom insert300through the pendant assembly800as the mobile crane lifts the boom. Different lengths of pendants assemblies' may be used to adjust the height the suspension assembly section362may rise above the boom insert300before lifting the boom insert300. In other embodiments, the retention mechanism may be adjustable to control the length that the post inserts802,804may rise above the boom insert300. For instance, when the retention mechanism is a slot814in the post insert802,804and a pin816extending into the slot814, the pin816may have different locations in which it may be inserted to adjust the height that the suspension assembly section362may raise.

FIGS. 12aand 12billustrate another embodiment of an insert1201having intermediate suspension connection disposed between a first end1205and a second end1206of the insert1201. The insert1201has an attachment mechanism disposed on each end1205,1206. The attachment mechanism includes tabs and apertures as described previously with respect toFIG. 3. Other connection types are possible such as hooks, bolts, clamps, and the like. The insert1201is similar in structure to the embodiment ofFIG. 3and like elements will not be repeated.

The insert1201has a cross member1207coupled to a first lower chord1208and a second lower chord1209. The cross member1207has a first sheave1210and a second sheave1211mounted thereto. The first sheave1210and the second sheave1211rotate about the cross member1207. A pendant assembly1212has a first flexible pendant1213and a second flexible pendant1214connected by a cross pendant1215. The first pendant1213couples to the first lower chord1208at a first intermediate suspension connection1203, and the second pendant1214couples to the first lower chord1209at a second intermediate suspension connection1204. Each lower chord may have additional intermediate suspension connections such as intermediate suspension connection1216and intermediate suspension connection1217. The first pendant1213and the second pendant1214are configured to couple to any of the intermediate suspension connections. By changing the intermediate suspension connection to which the pendants connect, the effective length of the pendant may be varied.

FIGS. 13aand 13bdepict another embodiment of an insert1301having an intermediate suspension connection in the form of a drum disposed between a first end1305and a second end1306of the insert1301. The insert1301has an attachment mechanism disposed on each end1305,1306for attachment to an adjoining insert. The attachment mechanism may include tabs and apertures as described previously with respect toFIG. 3. Other connection types are possible such as hooks, bolts, clamps, and the like. The insert1301is similar in structure to the embodiment ofFIG. 3and like elements will not be repeated.

The insert1301has a cross member assembly1307coupled to a first lower chord1308and a second lower chord1309. The cross member assembly1307has a first drum1310and a second drum1311. Each drum1310,1311has an associated flexible pendant1312that wraps around the drum1310,1311and is coupled to drum1310,1311. A free end1313of the flexible pendant1312extends away from the drum1310,1311and is configured to connect to a suspension assembly. The drum1310,1311may be rotated to adjust the length of the flexible pendant1312extending from the drum1310,1311. In some embodiments, the drum1310,1311may be manually rotated and have a brake to hold the drum1310,1311in place when the desired length of flexible pendant1312is extended. In other embodiments the drum1310,1311may be a powered drum rotated by an electric actuator such as a motor, a hydraulic actuator such as a hydraulic drive, or a mechanical connection.

In some embodiment the powered drum may adjust the length of the flexible pendant1312automatically. For example, the flexible pendant1312may have a tension sensor that measures the tension in the flexible pendant1312. The powered drum may adjust the length of the flexible pendant1312until the tension in the flexible pendant1312matches a set value. In another embodiment a stress in a chord of an insert may be measured and the length of the flexible pendant1312may be adjusted to maintain the stress within a predetermined window. Other types of sensors and changes to the flexible pendant1312length are possible and embodiments need not be limited to tension in the flexible pendant1312or stress in a cord.

FIGS. 14aand 14bdepict another embodiment of an insert1401having an intermediate suspension connection disposed between a first end1405and a second end1406of the insert1401. The insert1401has an attachment mechanism disposed on each end1405,1406for attachment to an adjoining insert. The attachment mechanism may include tabs and apertures as described previously with respect toFIG. 3. Other connection types are possible such as hooks, bolts, clamps, and the like. The insert1401is similar in structure to the embodiment ofFIG. 3and like elements will not be repeated.

The insert1401has a cross member assembly1407coupled to a first lower chord1408and a second lower chord1409. The cross member assembly1407has a cylindrical capstan1410having a first flexible pendant1411and a second flexible pendant1412wrapped about the cylindrical capstan1410. The flexible pendants1411,1412include a first free end1413of the flexible pendants1411,1412that extends away from the capstan1410and has an end connection for connecting to a suspension assembly. A second free end1414of the flexible pendants1411,1412extends away from the capstan along a lower side of the insert and is coupled to either the first lower chord1408or the second lower chord1409. The lower chords1408,1408may each have multiple connections1415,1416,1417at which the second free end1414of the flexible pendant1411,1412may attach. By adjusting the position at which the second free end1414of the flexible pendant1411,1412attaches to the lower chords1408,1409, the extended length of the first free end1413of the may be adjusted. Additionally, the length of the first free end1413of the flexible pendant1411,1412may be adjusted by changing the number of wraps of the flexible pendant1411,1412around the capstan1410.

FIGS. 15aand 15bdepict another embodiment of an insert1501having an intermediate suspension connection disposed between a first end1505and a second end1506of the insert1501. The insert1501has an attachment mechanism disposed on each end1505,1506for attachment to an adjoining insert. The attachment mechanism may include tabs and apertures as described previously with respect toFIG. 3. Other connection types are possible such as hooks, bolts, clamps, and the like. The insert1501is similar in structure to the embodiment ofFIG. 3and like elements will not be repeated.

The insert1501has a cross member assembly1507coupled to a first lower chord1508and a second lower chord1509. The cross member assembly1507has a cylindrical capstan1510having a first flexible pendant1511and a second flexible pendant1512wrapped about the cylindrical capstan1510. A free end1513of the flexible pendants1511,1512extends away from the capstan1510and has an end connection for connecting to a suspension assembly. An opposite end of the flexible pendants1511,1512is coupled to the capstan1510. The length of the free end1513of the pendants1511,1512may be adjusted by changing the number of wraps the flexible pendants1511,1512wrap around the capstan1510.

FIG. 16depicts another embodiment of an insert1601having an intermediate suspension connection disposed between a first end1605and a second end1606of the insert1601. The insert1601has an attachment mechanism disposed on each end1605,1606for attachment to an adjoining insert. The attachment mechanism may include tabs and apertures as described previously with respect toFIG. 3. Other connection types are possible such as hooks, bolts, clamps, and the like. The insert1601is similar in structure to the embodiment ofFIG. 3and like elements will not be repeated.

The insert1601has a cross member1607coupled to a first lower chord1608and a second lower chord1650. Flexible pendants1609,1651connect to the cross member1607and have free end1610,1652that extends away from the cross member1607towards a suspension assembly. The flexible pendants1609,1651have a plurality of fittings1611,1612,1613, or areas of enlarged cross section sometimes referred to as a button. The fittings1611,1612,1613secure within a connection on the cross member1607as will be described below. The fittings1611,1612,1613are set at a fixed length and depending on the particular fitting that is used to secure the flexible pendants1609,1651the effective length of the flexible pendants1609,1651may be adjusted.

FIG. 17is a perspective view of the second end1606of the insert1601ofFIG. 16showing the flexible pendants1609,1651.FIG. 18is a detailed view of a flexible pendant1609positioned along the first chord1608and having a free end1653attached to the first chord1608. The first chord1608may have multiple locations in which the free end1653may attach depending on the length of the flexible pendant1609.

FIG. 19is a detailed view of the connection ofFIG. 16and its interaction with the fittings1611,1612,1613of the flexible pendant1609.FIG. 20is a detailed cross section of the connection ofFIG. 16. The connection has tab pair1614that is coupled to the cross member1607through a conventional means such as welding. The tab pair1614has an aperture1615through which a pin1616may be inserted. The pin1616has a length greater than an external width of the tab pair1614such that the pin1616extends from both sides of the tab pair1614when it is inserted. A first cotter pin1617and a second cotter pin1618may secure the pin1616within the aperture1615of the tab pair1614. In other embodiments the pin1616may have a threaded end and be threaded within the aperture1615or threaded into a nut outside of the tab pair1614.

A sleeve1619has two legs1620with apertures1621that are similar to the aperture1615of the tab pair1614. In use, the legs1620are placed in the space between each tab of the tab pair1614such that the apertures1615of the tab pair1614and the apertures1621of the legs1620are aligned. The pin1616is then inserted through the apertures1615,1621securing the sleeve1619to the tab pairs1614. In other embodiments the legs1620may have an internal spacing wider than the outer width of the tab pair1614, or a single tab, such that in use the tab pair1614fits between the legs1620.

The sleeve1619ofFIG. 20is shown cut away so that the interaction of the fitting1622and the sleeve1619can be seen. The sleeve1619has a cavity1623having an internal diameter that is larger than an external diameter of the fitting1622. At one end of the cavity1623, there is a portion1624having a reduced diameter that is larger than an external diameter of the flexible pendant1609, but less than the outer diameter of the fitting1622. A slot1625that is wider than the flexible pendant1609, but narrower than the fitting1622is cut along one side of the sleeve1619. Thus a portion of the flexible pendant1609between fittings may be inserted into the cavity1623through the slot1625. The flexible pendant1609may then be moved with the fitting1622sliding into the cavity1623. The fitting1622may slide within the cavity1623until the fitting1622reaches the reduced diameter portion1624of the cavity1623. An aperture1626passes through the sleeve1619across the cavity1623at a distance just past the length of the fitting1622such that when the fitting1622is placed in the cavity1623a second pin1627may be inserted through the aperture1626locking the fitting1622within the cavity1623.

The fitting1622may be a sleeve swaged to the flexible pendant1609, a spelter socket, or in other embodiments it may be a different enlarged diameter portion such as a change in a braid or weave of a flexible pendant1609. The enlarged diameter portion is preferably formed without looping the flexible pendant1609on itself which may reduce the strength of the flexible pendant1609.

In the swaging process the sleeve is passed over the flexible pendant1609to a desired location. The sleeve is then deformed around the flexible pendant1609to affix it in place. Additional sleeves may be swaged to the flexible pendant1609to form multiple fittings.

In some embodiments, the fitting1622may be a spelter socket formed on an end of a cable. In such embodiments, the flexible pendant may be formed from multiple sections of cable. A first section is configured to couple to the suspension assembly at a first end and has a first spelter socket on the opposite end. The spelter socket receives a broomed end of the cable and is filled with a filler material such as molten zinc. The molten zinc hardens in place maintaining the broomed shaped of the cable and holding the cable within the spelter socket. A first end of a second section of cable is inserted into a second spelter socket coupled to the first spelter socket. The first end of the second section is broomed and the filler material is poured into the spelter socket holding the second section in place. An end termination in the form of a third spelter socket may be placed on an opposite end of the second section, or the third spelter socket may have a fourth spelter socket coupled to it for receiving another section of cable. Multiple sections of cable may be coupled together using this procedure until a desired number of fittings is obtained.

The fitting1622may be removed from the cavity1623by removing the second pin1627and sliding the fitting1622from the cavity1623. The flexible pendant1609can then be removed by sliding it out of the sleeve slot1625. The effective length of the flexible pendant1609may be adjusted by inserting different fittings within the cavity1623.

Embodiments of the invention are further directed to a method for erecting a crane using the described intermediate suspension connection column segment. In the method, at least three boom segments are assembled end to end with at least one of the boom segments having an intermediate suspension connection between the ends of the boom segment. The at least three boom segments are then coupled end to end to form a suspension column. A first end of the assembled suspension column is then coupled to a hinge pivot point, such as a pivot point on a rotating bed or a pivot point on an end of a boom. A plurality of suspension members are then coupled end to end to form a suspension to connection a second end of the assemble suspension column to a mast. A suspension element is then coupled between the intermediate suspension connection and the suspension. The suspension is then tensioned to lift the second end of the boom. The mast may be a live mast in which tensioning the suspension members is done by rotating the mast proximate the carbody, or it may be a fixed mast in which instance tensioning the suspension is done by shortening a distance between the mast and the suspension.

It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. For example, instead of two separate post inserts being used a single post insert spanning the two posts may be used. Or the flexible pendant could be replaced with a single rigid pendant that did not expand. Additionally the suspension connection could be mounted on a location other than the lower cross member so long as it is disposed between the two ends of the boom insert.