Abstract: An apparatus for dismounting and mounting a high-voltage line T-connector in a hot-line operation includes a lifting platform, a four-axis platform and an end-effector mechanism; the four-axis platform and the end-effector mechanism are both electrically conductive structures; the four-axis platform is fixedly mounted on the top of the lifting platform, and an insulating layer is provided between the four-axis platform and the lifting platform; the four-axis platform is movable in the X direction, the Y direction, and the Z direction, and is rotatable around the Z direction; the four-axis platform is provided with an equipotential mechanism; the end-effector mechanism is detachably fastened to the four-axis platform; and a bolt loosening/tightening mechanism or a nut cutting device capable of moving in the X direction, the Y direction, and the Z direction is provided on the end-effector mechanism.

Abstract: A pipe replacement system and method are shown. Configurations are shown that include a pulley that does not damage a bursting tool, as the bursting tool is pulled into a pit. Configurations are also shown that include a boom that does not need an extraction cage for the bursting tool.

Abstract: A crane includes a boom and a derricking mechanism, wherein: the derricking mechanism includes a linking device connecting one end of a guy line to a distal end of the boom; the linking device includes a joint connected to one end of the guy line, and a support device provided on the distal end to support the joint so as to locate the joint at a position away from the back surface and opposite to the ventral surface; and the support device includes a holding member which holds the joint, the holding member allowing the position of the joint to be selectively changed to a plurality of different positions in a first direction perpendicularly intersecting an axis of the boom and a rotary axis of the boom.

Abstract: A crane includes: a boom; a jib; a front post that is swingably attached to a tip end side of the boom; a rear post that is swingably attached to the tip end side of the boom; a post-side pendant member, with one end of the post-side pendant member being attached to a tip end of the rear post; a boom-side pendant member, with one end of the boom-side pendant member being attached to another end of the post-side pendant member, and another end of the boom-side pendant member being attached to the boom; and a post driving device having a link mechanism that rotates the rear post in a range including a position at which the rear post is swung down to the front post side and a position at which the rear post is swung down to the boom side, while the boom is held down in a horizontal position.

Abstract: In a method for determining a tilt angle of a crane, a portion of the crane is rotated about a pivot point. A Global Navigation Satellite System (GNSS) receiver antenna is disposed on the portion of said crane. At least three locations of the GNSS receiver antenna are determined by a GNSS receiver in a geo-referenced coordinate system during the rotating. A tilt angle of the crane based on the at least three locations of said GNSS receiver antenna is determined by a processor.

Abstract: A mobile crane includes a main body and extendable axles, which are selectively re-positioned relative to the main body through strategically positioned apertures. The axles may be automatically locked to the main body in a desired one of the multiple positions without operator intervention. The axles one or more tapered ends for connecting to side frames, which may support crawler tracks. The tapered ends of the axles extend through openings located in the frames such that they are removably connected to an outside or exterior portion of the frames relative to the main body.

Abstract: Provided is a hybrid construction machine together with a method for controlling that construction machine in a manner ensuring the operability of its combined operations regardless of fluctuations in the load on its work machine.

Abstract: Various lifting systems are described that use one or more of the following features. A method for setting an adjustable height upper pulley on a tall structure; load transfer from a suspended load to a tall structure; fan-based stabilizer; stabilizer or horizontal load position control mechanism using a closed loop of cable and traction winch for a crane application; crane-based lifting system that uses a closed loop of lifting cable looped around a traction winch; and a stabilizer or horizontal load position control mechanism that does not need a closed loop of cable. Other embodiments are also described and claims. Other embodiments are also described and claimed.

Abstract: A hoisting crane comprising a substantially hollow vertical column, a jib, a jib winch and a jib hoisting cable is provided. The crane further a hoisting winch and an associated hoisting cable, the hoisting winch being disposed in the column, so that the hoisting cable extends from the winch through the column. The jib winch and the hoisting winch are arranged on a rotatable winch support, such that the winch support is mounted movable with respect to the vertical column. The hoisting crane further comprises a deep water winch positioned below the rotatable winch support and an associated deep water cable for raising and lowering a load extending through the rotation axis of the rotatable winch support, so that the deep water cable extends from the deep water winch through the hollow vertical column. The present invention further relates to a vessel provided with such a crane.

Abstract: A heavy duty vehicle recovery system employs a crane/tow boom assembly which is pivotally mounted to an upright assembly and is transformable between various positions. Two variably positionable booms with slidable extensions are provided. The crane/tow boom assembly extends rearwardly from the lower portion of the upright assembly. When the upright assembly is in an upright position, the boom assembly is upwardly pivotal from the upright assembly. When the upright assembly is in a reclined position, the crane/tow boom assembly is pivotally transformable to a transport position generally parallel to the upright assembly. The crane booms may be independently positioned at different elevational angles and different extensions.

Abstract: A level-controllable crawler crane includes two crawler supports with rotating crawlers, which crawler supports are connected by a transversal bridge. A superstructure of the crawler crane includes a crane jib pivotable about a vertical axis and connected to the transversal bridge. A pivotable articulation connects the transversal bridge to the crane superstructure. At least one of the crawler supports is connected to the transversal bridge by a double link having a lower and an upper link. The lower link is articulated on the crawler support by a crawler support lower pivotable axis and on the transversal bridge by a transversal bridge lower pivotable axis. The upper link is articulated on the crawler support by a crawler support upper pivotable axis and on the transversal bridge by a transversal bridge upper pivotable axis. A drive pivots the links about the pivotable axis associated therewith.

Abstract: A crane including an inner boom, an outer boom, a plurality of guide assemblies arranged along the length of the inner and outer boom and adapted for guiding a plurality of lines, and a multi-line material handling system including a first line having an outgoing portion extending to a sheave block, and an incoming portion returning from the sheave block to a supported anchor device, and a second line having an outgoing portion extending to the sheave block, and an incoming portion returning from the sheave block to the supported anchor device.

Abstract: The present invention relates to a crane control apparatus for a crane where a load is suspended on a crane cable from a cable suspension point of the crane, comprising an observer for estimating at least the position and/or velocity of the load from at least one sensor input of a first sensor by using a physical model of the load suspended on the crane cable, whereby the physical model of the observer uses the load position and/or the load velocity as a state variable.

Abstract: A crane characterized in that it comprises a lower vertical boom (10) and an upper horizontal boom (12), mutually connected through a joint element (20), in that the lowest part of the vertical boom is connected through a pedestal (14), the pedestal further comprising a slew ring for rotating of the crane about a vertical axis (16), and a tension rod (22) is arranged between the pedestal and the joint element in a distance from the vertical boom and mainly parallel to this in a normal position of the crane.

Abstract: A portable mechanical lifting and lowering device for mounting in or on a host vehicle with various lifting and lowering configurations that enable the user to lift, lower, move and operate items, equipment and farm style implements using hydraulic, electrical, or other mechanical means of power, including but not limited to a lifting mechanism that mimic's the lifting ability of a farm tractor style three point hitch configuration by attaching to the trailer hitch receiver port of a host vehicle and being operated with an implement attached; and a mechanism that can lift or lower items into the earth, or other surface, in a straight or twisting fashion; and a trailer hitch attachment for a trailer hitch ball that can be easily lifted and lowered; and a crane style mechanism that can lift, lower or move items, all incorporated in this one device.

Abstract: A davit comprising a column which is mountable for rotation about a generally upright axis and a jib, the jib being attached to the column, characterised in that the column is provided, on a first side thereof, with ribs defining a first channel.

Abstract: Hoisting crane (20), comprising a substantially hollow jib (24,-124; 324) having a longitudinal axis, and comprising one or more hoisting cable guides (47, 48, 49; 147; 347). The jib comprises at least one jib leg (29; 129; 329) extending between a jib connection member (26) and a jib hoisting end (27; 127; 327), wherein the at least one jib leg comprises one or more hybrid portions (160; 360) comprising two elongated hollow casings (170; 370) substantially parallel to each other and substantially parallel to the longitudinal axis of the jib, and wherein between the two casings a truss (171 371) is provided to rigidly connect the two castings.

Abstract: A backstay spreader attachable between a pair of backstay sections on a crane includes first and second members each having a backstay section connector at a first end and a pivoting joint connector at a second end, the pivoting joint connectors being used to hold the first and second members together with a pivotal connection and each having an extending portion extending away from the pivotal connection, with an angle between the extending portions. The backstay spreader also includes an actuator mounted between the pivoting joint connectors. The actuator controls the angle between the extending portions of the two pivoting joint connectors, which defines an angle between the first and second members.

Abstract: The invention provides a swing drive device that is capable of energy conservation by limiting loss of hydraulic fluid pressure energy resulting from discharge of the hydraulic fluid pressure energy as thermal energy into the air during acceleration or deceleration of swinging action and transforming motion energy to electric energy during deceleration of swinging action, and also enables cost reduction by making components and parts compact.

Abstract: A hoisting crane with an even reeving system having a substantially hollow vertical column, which has a foot, a top and a body disposed between the foot and the top. An annular bearing structure disposed around the substantially hollow vertical column. A jib connection member disposed on the annular bearing structure and rotatable about the substantially hollow vertical column. A jib connected to the jib connection member.

Abstract: This invention provides with a travelling working machine comprising an upper rotating body with a rotating frame and winches, a pair of right and left boom support frames formed in the rotating frame, and axial portions of the winches mounted inside rear portions of the boom support frames, characterized in that the boom support frames have openings formed by being cut out along small-diameter portions of the winches than maximum-diameter portions thereof, thereby capable of providing with the travelling working machine having the rotating frame in such a manner that the strength of the frame can be enhanced and a load bearing force can be strengthened highly without enlarging a rear swing radius of the upper rotating body.

Abstract: The present invention provides a construction machine in which a plurality of winches are arranged to be overlapped vertically at a rear part of an upper rotating body. Therefore, a space that the winches occupy is reduced, so that the space of the upper rotating body can be utilized effectively, and a radius of rotating rear end can be reduced.

Abstract: The invention refers to mobile harbor crane (1) for the handling of ISO containers from smaller container ships (3), with steerable wheel mechanism (4.1) with multiple axles and supports (4.2) telescoped laterally, as well as upper carriage (5) holding rigid tower (6), boom (7), drive aggregates and a counterweight, and connected to lower carriage (4) via a slewing gear. The new handling equipment is intended to make it possible to load and unload smaller container ships (3) efficiently and to connect different areas of a container terminal as an integrated component of an automated container terminal. According to the invention, boom (7) is articulated in the lower area of upper carriage (5)'s steel structure to accommodate luffing and holds at the tip of the boom, boom head (9), connected via parallelogram system (8), consisting of two pieces in a horizontal direction, that is an upper first part (9.1), connected to luffing boom (7) via parallelogram system (8), and a lower second part (9.

Abstract: A self-propelled crane provides a possibility to lift the heavy and large-size loads and includes a mobile unit as a base unit, which carries a pivoting platform, a traverse, a boom, the bottom of which is by the hinge connected to the platform and the upper end of a boom is attached to a luffing arm. The upper end of the boom has the first hoist cable roller and another end of the luffing arm has the second hoist cable roller. The first hoist cable is connected to a crane hook mechanism.

Abstract: The invention concerns a material transloading equipment unit with an undercarriage and a turntable connected with this undercarriage by means of a track ring, on which an arm that can be pivoted by means of at least one hoisting cylinder is pivot-mounted. According to the invention, on the one hand at least one additional pivot point for the arm is provided on the turntable and/or on the boom foot, and at least one additional pivot point is provided in the arm or in a pivot plate on the arm. This allows a number of possible combinations for the kinematics of the arm.

Abstract: The invention relates to a loading and unloading plant in a sea or river port, in particular for ISO containers, comprising a container storage facility which is located along a quay and consists of individual line-type storage modules and at least one loading device for handling loads to and from a vessel on the quay. In this case, the loading plant for loading and unloading loads comprises at least one mobile harbor crane (5), whose load jib extends into the area of at least one transfer point (6) which is provided within a container storage facility (7) consisting of a number of storage modules (9, 9.1, 9.2) with a number of container rows that depends on the width of the module, and forms an interface between the mobile harbor crane (5) and the storage modules (9, 9.1, 9.2) of the container storage facility (7).

Abstract: A winch spooled with a cable is provided for mounting on the boom of a host vehicle. The winch is surrounded by a frame housing that is capable of withstanding the forces applied by the host vehicle. A braking mechanism is provided for controlling the spooling and unspooling of the cable. The winch is mounted on the boom of a host vehicle by a conventional attachment that is used for other custom tools such as buckets of a backhoe.

Abstract: Unit cranes consist of three jointed arms (13-15), the middle arm (14) being in the form of a polygon comprising a number of units jointed together, the mobility of the units being arranged by influencing the units internally. The object of the invention is to achieve improved traction curves and speed curves, and this is effected by influencing the movement of the units from the outside by means of a hydraulic mechanism.

Abstract: A winch spooled with a cable is provided for mounting on the boom of a host vehicle. The winch is surrounded by a frame housing that is capable of withstanding the forces applied by the host vehicle. A braking mechanism is provided for controlling the spooling and unspooling of the cable. The winch is mounted on the boom of a host vehicle by a conventional attachment that is used for other custom tools.

Abstract: An upper cover has a curved portion formed in its end portion on the side near a work front for avoiding interference with the work front. The curved portion comprises a recessed surface having a center axis aligned with the axis of a vertical pin of a swing post, a first stepped portion provided at a lower end of the recessed surface and defining a substantially constant gap with respect to a locus drawn by a rear projecting portion of the swing post when the work front is swung, and a second stepped portion provided in an intermediate portion of the recessed surface in the direction of height thereof and having a substantially horizontal surface for assuring a foothold. The recessed surface is configured to extend along a locus drawn by a back surface of the boom when the work front is swung in its minimum-turn posture, while defining a gap with respect to the locus.

Abstract: The present invention relates to a mobile crane with a telescoping jib hinged to its superstructure which jib can be luffed by a luffing ram which is hinged to the telescoping jib and the superstructure, with a guy pole hinged on the rear side of the telescoping jib in the upper area of its hinge section which guy pole can be raised by a hydraulic ram, and with a winch by which a guy rope extending from the tip of the guy pole to the top part of the inner telescope section or a truss of an upper telescope section can be tautened. In accordance with the invention the guy pole is guyed over the superstructure, the base or the hinge axle of the hinge section or the lower area of the hinge section by a rope or by a rod of a predetermined length and the winch is positioned in the area of the tip of the guy pole.

Abstract: A lifting system for removing and installing equipment on aircraft. The lifting system comprises a base and a lifting assembly supported by the base. The lifting system also comprises linear outriggers and at least one offset outrigger. The linear outriggers and the at least one offset outrigger are connectable to the base to provide additional stability for the lifting system during operation. The lifting assembly includes a boom having telescoping sections. The boom may be tilted about a horizontal axis relative to the base and rotated about a vertical axis relative to the base for increased maneuverability around and increased access to the aircraft.

Abstract: A deflection device allows deflection correction control of suspended cargo for deflections having both parallel deflection and skew deflection components. The suspended cargo is held by a suspension tool suspended from a trolley via ropes and is carried together with movement of the trolley. The device has mark detectors provided under the trolley with a range of vision facing downwardly and a corresponding plurality of marks provided opposite of the mark detectors on the suspension tool. A picture processing device generates picture signals of the first and second marks detected by the mark detectors. A deviation amount computing device calculates the deviation of the first and second marks, and a deflection amount calculating device calculates the amount of parallel deflection and the amount of skew deflection based on the computed deviation amount.

Abstract: A boom lift apparatus includes a boom assembly having an elongated lower mast member, an elongated upper boom member and a coupler member connected to a lower end of the upper boom member and an upper end of the lower mast member such that the upper boom member extends in a cantilevered inclined relationship to the lower mast member, and a plurality of different mounting members, each being adapted to mount the boom assembly at a lower end of the lower mast member to a different one of a plurality of different support structures.

Abstract: A truck mounted crane assembly includes a turntable lock, a boom rest which interacts with the piston and cylinder device, and a swing away hoist mount. The turntable lock includes a pin which is manually retractable upon rotation of a handle from a position preventing relative rotation between a turntable and a pedestal to a position allowing such relative rotation and which can be secured in the first and second positions. The boom rest is mounted on the boom and rests on the cylinder of the piston and cylinder device when the boom is lowered to a predetermined position, thus taking much of the pressure off the piston. The boom rest is movable from a position in which it is capable of supporting the boom to a position in which it is incapable of supporting the boom and in which the boom is thus lowerable below the predetermined position. The provision of the turntable lock and boom rest obviates the need for a cradle rest for the boom.

Abstract: A recovery vehicle (10) having a 360.degree. rotatable hoist unit (22) with a boom member (26) mounted onto a vehicle frame (12), is described. The vehicle frame contains a single rear axle (16) having wheels (18) adjacent the sides (12E) of the vehicle frame. A first outrigger assembly (50) is mounted onto the underneath portion (12B) of the vehicle frame adjacent the distal end (12C) of the vehicle frame. The vertical arms (64, 66) of the first outrigger, pivot due to a rotatable yoke (62B) in the end (62A) of the horizontal arm (62) to enable the first outrigger assembly to extend backwards of the distal end of the vehicle frame to act as anchors during pulling by the hoist unit. A second outrigger assembly (52) is mounted between the proximal end (12D) of the vehicle frame and the rear axle.

Abstract: Foldable link rod system to be placed on a travelling frame comprises pivotally suspended link rods (16, 18) for raising and lowering an operation platform (14). A rotating stool (20) constitutes the connection between two link rods (16 and 18) which are placed in continuation to each other. The one part of the rotating stool (20) is linked to the free end of the first link rod (16) which at its opposite end is pivotally linked to a swinging rod system (26, 28, 30, 32). The second link rod (18) is linked to the other part of the rotating stool and at its other end it is linked to the operation platform (14). The two link rods are pivotal by means of each of their swinging devices (54-70) which are supported on the travelling frame (10, 12) and the rotating stool (20), respectively.

Abstract: A mobile vehicular apparatus for moving an operator around a three-dimensional aerial work location such as an electric cable or wire supported on posts includes a mobile vehicle having a vehicle body, a boom upwardly extensibly and downwardly collapsibly mounted on the vehicle body, an operator's cabin mounted on a distal end of the boom, cabin having a vertical recess defined in a rear side thereof, at least one manipulator operatively connected to a front side of the cabin, and a lifter operatively connected to the rear side of the cabin. The lifter is collapsibly storable in the recess and extensible from the recess with a distal end portion of the lifter being positioned in overhanging relation to the cabin, the lifter supporting a winding device on the distal end portion.

Abstract: A mobile vehicular apparatus for moving an operator around a three-dimensional aerial work location such as an electric cable or wire supported on posts includes a mobile vehicle having a vehicle body, a boom upwardly extensibly and downwardly collapsibly mounted on the vehicle body, an operator's cabin mounted on a distal end of the boom, the cabin having a vertical recess defined in a rear side thereof, at least one manipulator operatively connected to a front side of the cabin, and a lifter operatively connected to the rear side of the cabin. The lifter is collapsibly storable in the recess and extensible from the recess with a distal end portion of the lifter being positioned in overhanging relation to the cabin, the lifter supporting a winding device on the distal end portion.

Abstract: A removable hoist system for a doorway of a van which comprises, when in position, a post vertically mounted in the doorway and an arm having one end secured to the post. The arm during operation extends horizontally from the post and a lift mechanism is secured to the other end of the arm, for lifting or lower objects with respect to the van. A lower plate is secured to the floor of the van where the post is mounted and an aperture centrally positioned in the plate, and an upper plate is secured to a frame portion of the van in the upper part of the doorway, vertically above the lower plate with an aperture centrally positioned in this upper plate. Pins removably received in the aperture of the plates to hold the post in vertical position during operation outwardly extend from the ends of the post.

Abstract: An improved locomotive crane boom generally indicated at 10 has of a first member 11, second member 12, and third member 13 each pivotally connected at various pivot points to one another and to locomotive crane 14. A series of pistons and cylinders, 19, 20 and 21, powered by hydraulic pump 23 and fluid source 34, may be selectively extracted or retracted thereby permitting the improved boom to be positioned at any point along the length of a typical gondola car 17 to be unloaded. In operation, locomotive crane 14 with the included improved boom 10 does not need to be uncoupled from gondola car 17 for unloading since the improved boom may be articulated such that unloading magnet 24 or any other appended appliance may be positioned across the entire length of car 17 through the selected extraction and retraction of the pistons and cylinders and pivoting of the boom members 11, 12 and 13.

Abstract: An invalid lifting device is disclosed. A mast is mounted to a frame to rotate about a vertical axis. A boom is mounted to the mast to swing with the mast and to pivot about a horizontal axis. A sling for supporting an invalid extends from the end of the boom. A first motor drives the mast to rotate and a second motor is mechanically linked with an extendible strut to raise and lower the boom. A control box is provided in the proximity of an invalid as he is seated in the sling to allow the user to select an elevational and rotational movement. A computer controls movement of the device based upon input at the control box.

Abstract: A crane, particularly a large mobile crane, including an undercarriage (1); a revolving joint (3) on the undercarriage (1); and a superstructure on the revolving joint (3). The superstructure includes a central part (5) rotatably mounted on the revolving part (3), a boom connected to the central part (5), a swing part (6), and a horizontal swing bearing (9) pivotally mounting the swing part in upwardly swingable manner on the central part (5). The crane further includes at least one winch mounted on the swing part (6) and a retraction mechanism at the end of the swing part (6) opposite the swing bearing (9). The retraction mechanism includes a pulley head (16) and a bracing (25) for the boom.

Abstract: A wheel crane wherein the maximum radius of pivotal motion of a boom is minimized and the boom foot mounting point can be positioned as rearwards as possible to realize an increase of the boom length. The wheel crane comprises a lower running body, an upper pivotal body, a boom mounted for up and down pivotal motion around a boom foot pin on the upper pivotal body, at least two winch drums and guide sheaves disposed at rear locations of the pivotal body. The boom foot pin is mounted at an end portion of the base end portion of the boom on the rear face side of the boom and at a location of the upper pivotal body rearwardly of the center of a rear axle of the lower running body.

Abstract: An apparatus for increasing the available hook raising and lowering distance is attached to a crane or other lifting structure having a boom and at least one lifting tackle utilizing at least one lifting line connected to a prime mover. The apparatus utilizes a support means attached to the crane boom substantially at the connection point of an existing upper tackle. A fixed, lower gripper platform is suspended from the support means and has at least one linear winch grip mounted thereon. A movable, upper gripper platform is connected to at least one lifting line associated with the lifting tackle. The upper gripper platform has at least one linear winch grip mounted thereon. The upper gripper platform is also adapted to reciprocate between the lower gripper platform and the upper tackle in response to the prime mover drawing in or paying out the lifting line. At least one extended load line for attachment to a load passes through the linear winch grips on the lower and upper gripper platforms.

Abstract: Each pair of wheels is interconnected by a tie-rod assembly. The tie-rod assemblies include ring gears connected with each of the wheels, and drive motors including drive gears mesh with each ring gear whereby the tie-rod assemblies enable synchronous turning movement of the wheels when the drive motors are actuated.

Abstract: A lightweight, self-powered, transportable crane assembly is disclosed which includes a frame that can be selectively coupled to and uncoupled from the bed of a transport vehicle or carrier, such as a pick-up truck or trailer. The frame assembly also includes stabilizing legs which can be extended laterally from the frame assembly to stabilize the crane during use and further to allow the crane assembly to be self supporting apart from the truck or trailer. The crane assembly also can be coupled to a ballast structure such as a water tank or the like, to permit its use apart from the transport vehicle.

Abstract: A stacker-reclaimer with a luffing and slewing mounting supporting a boom structure with a main, forwardly extending boom having a material conveyor running along it, and a rearwardly extending tail boom with a counterbalance weight depending from its rear end. The tail boom is at a higher level than the main boom to provide clearance for a feeder conveyor to the a material conveyor. The counterbalance weight is attached by a pivot on the tail boom and is displaceable about the pivot by a control cable attached to a non-luffing part of the luffing and slewing mounting forwards of the luffing axis whereby the weight is displaced forwards in relation to the pivot in upward luffing movements of the boom structure. This compensates for the rearward displacement of the rear end of the tail boom in such movements, and reduces the maximum overturning moment to be resisted in the working luffing range.

Abstract: To enable the crane driver of a double link level luffing crane to adapt the height of his cab above the ground to the size of the ship to be loaded or unloaded, the drivers cab is mounted at the end of a separate cab link having a hinge connection with a carriage movable on the strut member of the crane.

Abstract: A self-erecting traveling crane having a machinery platform rotatably mounted with respect to a carbody utilizes a concentric support ring, a boom foot carrier pivotably mounted to the platform and rolling on the support ring, and a counterweight carrier with trailing counterweight pivotably mounted to the platform and rolling on the ring. A mast and boom are mounted near a forward end of the boom foot carrier. To change location for use, the crane can be rigged to move in forward or rearward direction carrying its support ring. A travel strut is pivotably mounted to an inner end of the boom foot carrier. A boom foot carrier tension pendant extends from the top of the travel strut to an outer end portion of the boom foot carrier. A live boom suspension linkage connects the points of the mast and the boom. Boom suspension pendants extend from the mast point to the trailing counterweight. A gantry is mounted on the machinery platform over a platform counterweight.