Abstract: An inspection apparatus for inspecting horizontal tubes in an industrial environment includes a drive module including a pair of wheels to engage a top tube of a vertically arranged layer of tubes, a telescoping pole, a sensor carriage assembly coupled to the telescoping pole, a lowering mechanism operationally coupled to the telescoping pole to selectively extend or retract the telescoping pole providing a selected vertical position of the sensor carriage assembly, and an encoder including a passive wheel, a spring, and a sliding coupler. The spring biases the passive wheel toward the top tube to ensure contact between the passive wheel and a surface of the top tube.

Abstract: A pipe handling system for handling drill pipe on a drill rig may include a lifting system configured for handling a load of a pipe stand and a first pipe handling robot arranged at or near a drill floor of the drill rig and configured for manipulating a bottom end of the pipe stand between a setback area on the drill floor and well center. The system may also include a second pipe handling robot arranged at or near a racking board of the drill rig and configured for manipulating a top end of the pipe stand between the racking board and well center. The first pipe handling robot may have a base that is supported from a location outside a plan view envelope of the setback area of the drill floor.

Abstract: A robotic harvesting system includes a base, a linear transport, a robotic arm, and an end effector. The base is configured to move in a direction of travel. A linear transport is mounted to the base. The linear transport is configured to move along the base in substantially a same direction or opposite direction as the direction of travel. A robotic arm is mounted to the linear transport. The robotic arm has a proximal end and a distal end. The distal end of the robotic arm is configured to rotate toward and away from the base from a first joint. An end effector is mounted on the distal end of the robotic arm.

Abstract: A transfer device with unrolling device, intended for providing a label handling system in an IML machine (In Mould Labelling) with IML labels. The transfer device comprises at least four holders, which are movable between a first and a second position, wherein the first position has a first predetermined relationship between the four or several holders regarding the distance in the X-direction. The holders are intended for retrieval of IML labels from the unrolling device, which comprises a label web, the length of which extends in the Y-direction, with partially stamped out labels, connected to the web with micro connections. The second position has a second predetermined relationship between the four or several holders regarding distance in the X-direction. The holders are intended to deliver the IML labels to the label handling system.

Abstract: The present invention relates to a transport device for transporting objects along a transport track having a rail defining the transport track; at least one slide that is travelably guided at the rail; a coupling element which is provided at the slide and via which the slide can be driven; a first drive unit having a first drive means for driving the slid along a first transport section of the transport track; and a second drive having a second drive means for driving the slide along a second transport section of the transport track. The coupling element is configured to be in engagement in a shape fitting manner with the first drive means and to be in engagement in a force-fitting manner with the second drive means in the region of the second transport section.

Abstract: A robot arm includes a mechanical stop device having at least one counter-stop body having a shape, which, in interaction with a respective corresponding shape of a receptacle, is designed to retain the counter-stop body whenever the counter-stop body is inserted in one of a plurality of the receptacles. The receptacle retains the counter-stop body in both a circumferential direction and in a radial direction with respect to the axis of rotation of a swivel joint, in a form-fitting manner.

Abstract: Spacecraft servicing devices or pods and related methods may include a body configured to be deployed from a host spacecraft at a location adjacent a target spacecraft and at least one spacecraft servicing component configured to perform at least one servicing operation on the target spacecraft. The servicing device may include a communication device configured to receive data relating to the target spacecraft from a location remote from the spacecraft servicing device. The servicing device may include a coupling mechanism comprising at least one movable coupling configured to rotate the body relative to the target spacecraft when the spacecraft servicing pod is coupled to the target spacecraft. The at least one spacecraft servicing component may include at least one propulsion device positioned on a boom arm extending away from the body.

Abstract: A tailing arm mountable on a mast of an oil/gas rig and having a housing, a first arm rotatable relative to the housing, a second telescoping arm pivotally connected to the first, and third arm pivotally connected to the second arm. A roller on the end of the third arm receives and guides pipes being moved on to or off of the rig. A first rotation assembly controls the rotation of the first arm relative to the housing. A second rotation assembly rotates the housing relative to the mast. The tailing arm can be used to load pipe from multiple sides of the rig and to rack the pipe in the setback.

Abstract: An assembly for a robot includes a servo comprising an output gear, a servo housing connected to the servo, a rotary support connected to the servo and the servo housing, the rotary support being configured to rotate as driven by the servo; and a stopper assembly arranged at the servo housing and the rotary support. The stopper assembly is used to limit the rotary support to be rotatable in a predetermined range.

Abstract: Apparatus for supporting a nacelle of an aircraft engine is provided by the present disclosure. In one form, the apparatus includes a frame, a supporting structure extending from the frame, and a structure for attaching a nacelle, which is rotatably mounted on the supporting structure and can be rotated about a substantially horizontal axis.

Abstract: Methods and systems for allocating tasks to robotic devices are provided. An example method includes receiving information associated with task logs for a plurality of robotic devices and in a computing system configured to access a processor and memory, determining information associated with a health level for the plurality of robotic devices based on the information associated with the task logs. A health level for a given robotic device may be proportional to a current level of ability to perform a function, which may change over a lifespan of the given robotic device. Information associated with a plurality of tasks to be performed by one or more or the robotic devices may also be determined. The computing system may optimize an allocation of the plurality of tasks such that a high precision task may be allocated to a robotic device having a greater current health level than another robotic device.

Abstract: A device for a robot is disclosed. In the device for a robot, a first signal is transmitted from a robot control device to the robot, a second signal is transmitted from the robot control device to the device for a robot, and a third signal is transmitted from the robot control device to the device for a robot, the third signal being transmitted from the robot control device in a case where there is a communication error between the robot control device and the device for a robot so that the device for a robot is restarted via a reset circuit.

Abstract: A laboratory capper, decapper or combination capper/decapper includes a deck containing with a nest designed to hold an SBS-formatted tube storage rack, and a bit exchange magazine assembly containing one or more sets of adapter bits. The adapter bits are mounted on and unloaded from motor driven fittings, and are exchanged in order to cap or decap laboratory sample tubes or vials that have different head configurations. The bit exchange magazine assembly enables the bit to be exchanged robotically.

Abstract: An apparatus and method is provided for a shotgun stick for manipulating, removing and installing clamps and other devices to electrical connectors on electric power distribution systems. The shotgun stick includes an elongated, electrical insulating, support rod having a working end and a holding end. An electrical insulating head mounted on the working end of the support rod. A clamping mechanism is mounted within the head for extension from the head and retraction into the head. An actuating mechanism is mounted within the head for extending and retracting the clamping mechanism. A control module is mounted within the head for controlling the actuating mechanism to extend and retract the clamping mechanism. The control module including a receiver for receiving a control signal. A remote controller is operable by the operator holding the holding end to generate the control signal.

Abstract: Provided is a remotely operated manipulator which can be applied to a space which is wider on a back side than at an opening part, which has a simple structure, high stiffness, and high reliability. The remotely operated manipulator of the present invention includes: a circular base fixed to a wall surface; a beam which rotates on the circular base; a trolley which moves on the beam; and a mast which is raised and lowered with respect to the trolley and is mounted with a tool unit at a tip. Stiffness is improved by directly fixing the beam to the wall surface by a beam fixing device. Further, a work region is expanded by mounting a bending mast on the tip of the mast.

Abstract: A cover attachment structure for attaching a cover to a predetermined component of a robot includes a first component, a second component and a third component. The first component is disposed to the predetermined component of the robot. The second component is disposed to an inner part of the cover. The first component and the second component are engaged with each other through the third component. The first component and the second component are drawn to each other by the third component in a manner that the predetermined component and the cover are brought close to each other.

Abstract: A weight of a movable body is reduced by using two guides, smooth movement of the movable body is ensured, a decrease in life of the guides is prevented, and a workload during installation of the guides is reduced. A workpiece conveyor that conveys a workpiece includes chucks that hold a workpiece, and a movable body that supports the chucks and is movable in an X direction along first and second guides, which are disposed in parallel or substantially parallel spaced apart from each other, and the movable body includes a first structure guided by the first guide, a second structure guided by the second guide, and a joint that is provided between the first structure and the second structure, and allows one of the first structure and the second structure to swing with respect to the other about an axis of a swing shaft set parallel or substantially parallel to the X direction.

Abstract: A mobile telescopic crane has a telescopic jib with at least four part-jibs. Each of the part-jibs is constructed from at least two part-jib portions so as to be telescopic in a longitudinal direction. Part-jib portions arranged at a spacing from one another transverse to the longitudinal direction each form a jib portion with at least one flexurally rigid connecting element. A construction of this type of the jib means that an increase in the bearing load is easily achieved by increasing the area moment of inertia of the jib.

Abstract: A boom truck includes a telescopic lifting boom with a lifting unit and a support structure having a first support arranged on the chassis of the boom truck. A second support in the form of an elongated bearing and support beam body extends in the longitudinal direction of the boom truck. The beam body is pivotally mounted to the first support about a rear bearing axis, whereas the lifting boom is pivotally mounted to beam body about a front bearing axis. Actuators act on the beam body and the lifting boom as a unit and act to pivot the lifting boom about the front bearing axis.

Abstract: A mechanism for adjusting the orientation of an end effector (e.g., a non-destructive inspection sensor) during movement over a contoured surface, comprising: (1) a pneumatic or spring-loaded plunger shaft that facilitates positioning of an end effector onto a highly contoured surface by allowing a wide range of vertical motion; (2) a rocker pivotably coupled to a distal end of the plunger shaft, the rocker being pivotable about a horizontal axis to allow a pair of follower wheels coupled to distal ends of the rocker arms to follow the contoured surface and keep the end effector oriented correctly relative to the surface without tipping over; and (3) a hozzle (i.e., an end effector holder) attached to the rocker for rotation therewith, the end effector being coupled to the hozzle by an elastomeric gasket or a plurality of springs which allow the orientation of the end effector relative to the hozzle to change in response to contact forces.

Abstract: A side home-position device for a vehicle body assembly system for various vehicle types is disclosed, which can be used to return a common use side jig that controls a side panel to a working position of a main buck process. The device includes a post frame that is disposed in a vertical direction corresponding to the working position, a moving member that is movably disposed at the post frame in a width direction of a vehicle body and substantially supports the common use side jig, a main control unit in connection with the moving member and which returns the common use side jig to an original position, a clamper disposed on the moving member which clamps a matching portion of the common use side jig for the moving member, and an operating portion disposed at the post frame and which moves the moving member in a width direction of the vehicle body.

Abstract: A work vehicle includes a first loader arm portion pivotably connected at one end to a frame of the vehicle and configured to slidably receive a second loader arm portion along an opposed end of the first loader arm portion. A mechanical linkage interconnects the loader arm portions and the frame. A fluid cylinder operatively connected between each of the frame and the loader arm portions is configured to raise and lower the loader arm portions between a retracted (lowered) position and an extended (raised) position. As the fluid cylinder is actuated to urge the loader arm portions toward the extended (raised) position, the mechanical linkage results in slidable movement of the second loader arm portion with respect to the first loader arm portion so that a collective length of the loader arm portions in the extended (raised) position is increased.

Abstract: The disclosure describes a loader having a loader boom and a tool carrier or a tool arranged on the loader boom. The tool carrier or the tool is connected at a first pivot point to the loader boom and at a second pivot point to a pivot linkage. The pivot linkage has first and second links which are pivotably connected to one another at a first link point. The first link is pivotably connected at a second link point to the loader boom. The second link is pivotably connected at a second link point at the second pivot point to the tool carrier or to the tool. A sensor is provided by means of which a pivot angle between the tool carrier or tool and loader boom can be detected. To protect the sensor in as effective a manner as possible, the sensor is positioned in a cavity on the loader. An actuating device is provided for the sensor, which extends partially through an opening formed on the cavity and connects the sensor to the pivot linkage.

Abstract: An apparatus is provided that includes phase preservation means having a reference shaft fixed to one side of frames supporting a plurality of components, a driven shaft revolving around the reference shaft with a predetermined distance spaced apart therebetween, a force transmitting part connected to the driven shaft and the reference shaft to restrict rotation of the driven shaft, and supporting parts that guide revolving of the driven shaft around the reference shaft when the supporting parts are rotated by a rotational force applied by the force generating part and allows a phase of the driven shaft to be preserved. The apparatus also includes a phase preservation part that is connected and fixed to one side of the driven shaft.

Abstract: A travel control section 60b is configured to control the revolution velocities of transversely opposite travel motors 51 and 52 such that when turning amount command signals are inputted from a turning amount operation dial 48, transversely opposite crawler travel devices 12a and 12b are caused to realize a turn according to the turning amount command signals by decelerating the traveling velocities of the transversely opposite crawler travel devices 12a and 12b from a target straight traveling velocity set by a travel operation lever 47 by equal values of velocity which are predetermined according to the turning amount command signals inputted from the turning amount operation dial 48 and further decelerating the traveling velocity of the crawler travel device 12a or 12b which is positioned inwardly relative to the other in the turning direction.

Abstract: Equipment for transferring biological products containers from an interface support to a transport device and vice-versa for biological containers, positioned at different heights. The equipment including a frame to which a holding device for biological products containers is connected vertically mobile with respect to the frame and provided with fingers suitable to hold, transfer and release a container for biological products. The frame is integer with a sliding device along a bar fixed to an inclinable body. The inclinable body being in its turn rotatingly connected to a sustaining body, and a regulation device for the inclination of the inclinable body, and consequently of the bar, with respect to the sustaining body being present in function of the difference of height existing between the interfacing support and the transport device for biological products containers.

Abstract: Embodiments of an instrument manipulator are disclosed. An instrument manipulator can include a track; a translational carriage coupled to ride along the track; a shoulder yaw joint coupled to the translational carriage; a shoulder pitch joint coupled to the shoulder yaw joint, the shoulder pith joint including an arm, a wrist mount coupled to the arm, struts coupled between the wrist mount and the shoulder yaw joint, and a shoulder pitch mechanism coupled to the arm; a yaw-pitch-roll wrist coupled to the wrist mount, the yaw-pitch-roll wrist including a yaw joint and a differentially driven pitch-roll joint; and an instrument mount coupled to the wrist. The various joints and carriages can be driven by motors.

Abstract: Tray filling machine, comprising: a first conveying device (2), structured so as to transport between a loading position (C) and an unloading position (S) along a direction of transport (X) a plurality of items (F) arranged in one or more distinct rows; a second conveying device (3), structured so as to transport a tray (V) on a movement plane (31) arranged in the proximity of the unloading position of the first conveying device (2) beneath the first conveying device; said first and second conveying devices (2,3) being synchronized in relation to each other in a manner such that the items (F) and the tray (V) transit contemporaneously at the unloading position and the items (F) can be arranged on the tray (V).

Abstract: A lifting device configured to autonomously position a wind turbine blade in such a way that it can be mounted on a wind turbine tower. The lifting device (1) comprises a boom structure (2) and is furthermore provided with a positioning device (4) which is connected to the boom structure and can be displaced along the latter. The positioning device comprises a mounting structure (4f) for detachably mounting the wind turbine blade on the positioning device. The boom structure (2) and displacement structure (4a) of the positioning device (4) form an assembly for the approximate positioning of the mounting structure (4f) with respect to the wind turbine tower. The positioning device (4) furthermore comprises additional means (4d, 4e) for accurately positioning the wind turbine blade with respect to the wind turbine tower.

Abstract: A saddle block assembly including a main body having a shipper shaft opening through the main body bottom end, and an eccentric pin opening in the main body top end, an eccentric pin received in an eccentric pin opening in the top end of the main body, and a wear plate support. The wear plate support has a pin receiving opening, the eccentric pin being received in the pin receiving opening. Wear plates are mounted on the bottom end of the wear plate support and are adapted to bear against the top of a dipper handle.

Abstract: A working machine (1) includes a frame (3), a body section (2) mounted to the frame (3) for pivotal movement about a vertical axis, a boom unit (7) having a plurality of booms, including a basal boom (7a), telescopically extendable from and retractable to one another. A support arm (14) is mounted to the body section (2) for pivotal movement about a horizontal axis. An end of the support arm (14) is coupled with the basal boom (7a). The basal boom (7a) is pivotable relative to the support arm (14) about a horizontal axis. A first hydraulically operable device extends from the body section (2) to the basal boom (7a) for pivoting the basal boom (7a) relative to the support arm (14) about the horizontal axis.

Abstract: A positioning system for attachment to a vehicle for operation of a power tool by a ground-based operator sitting in the vehicle provides a telescoping mast attached to the vehicle, a pivot bracket connecting an upper arm to the upper portion of the telescoping mast, mounting means for mounting the power tool on the upper arm; and power means for operating the power tool from the operator's position in the vehicle.

Abstract: An improved implement support device for using an implement with a motor vehicle, with the device having an implement support structure, a lift mechanism, and a swing mechanism, where the implement support structure is suitably adapted to support and manipulate useful implements, such as a snowplow blade, a pair of fork lift forks, a container, a platform, and the like, with the lift mechanism suitably adapted to move the implement vertically in both an upward and a downward direction and the swing mechanism suitably adapted to move the implement laterally in both a leftward and a rightward direction, and with the implement able to be concurrently moved both vertically and laterally by substantially simultaneous operation of both the lift mechanism and the swing mechanism.

Abstract: A working robot according to an embodiment includes an arm part and a plurality of motors. The arm part includes a plurality of arm members. The plurality of motors respectively drives the plurality of arm members. Herein, rated powers respectively corresponding to the motors are the same.

Abstract: A system includes a turbine lift. The turbine lift includes a mounting base configured to mount to a non-stable structure. The turbine lift also includes an arm coupled to the mounting base. The turbine lift further includes a stabilizing head coupled to the arm, wherein the stabilizing head is configured to connect with a turbine engine, and the stabilizing head is configured to stabilize the turbine engine while moving the turbine engine.

Abstract: An attachment for laterally shifting a working implement is provided. The attachment can have a primary frame having a first side and a second side, the primary frame can be connectable to the vehicle so that the primary frame extends substantially perpendicular to the vehicle. A secondary frame can have a first side and a second side and be moveably connected to the primary frame so that the secondary frame can move laterally relative to the vehicle. An extension frame can have a first side and a second side and be moveably connected to the secondary frame so that the extension frame can move laterally relative to the vehicle. A working implement, such as a mower, can be operably connectable to the extension frame so that the working implement can be shifted laterally relative to the vehicle using the attachment.

Abstract: A transfer robot includes a swivel base, a strut, first and second elevation arms, and a horizontal arm unit. The swivel base includes a base part to swivel about a vertical axis thereof and a extension part extending from the base part in one horizontal direction. The strut is vertically extended from a leading end of the extension part. The first and second elevation arms are provided to rotate about a horizontal axis. The horizontal arm unit is supported on the leading end portion of the second elevation arm to rotate about a horizontal axis.

Abstract: A device and a method for turning stacks of sheet-shaped material include a device for transporting the stacks into a pivot fork. The pivot fork is part of a turning unit and includes upper grippers, lower grippers and a stack stop. The pivot fork is open on one side to receive the stacks. The pivot fork is supported at its other end to pivot on a horizontal pivot shaft that extends in a direction transverse to a direction of introduction of the stacks and is disposed off-center relative to the pivot fork.

Abstract: Apparatus and methods for moving a tubular member to and from an elevated drilling rig floor. In one embodiment, the apparatus comprises a support structure configured to be positioned adjacent a pipe rack. A carrier is moveably coupled to the support structure, and a carriage is moveably coupled to the carrier. A trough extends longitudinally over the support structure and is moveably coupled to the carriage, the trough being configured to receive a tubular member. The trough is operable to tilt relative to the support structure. A lift arm is operable to move the carriage relative to the support structure thereby also moving the tubular member received in the trough. Indexers may urge the tubular member toward or away from the trough. Pick up arms are operable to retrieve a tubular member from an adjacent pipe rack, or to place the tubular there for storage.

Abstract: A blade handling apparatus includes a mount frame; a stinger boom carried by the mount frame; and a lift block assembly including a lift block carried by the stinger boom; a pair of rod housings carried by the lift block; a pair of push rods slidably carried by the pair of rod housings, respectively; and a pair of blade lock pins carried by the pair of rod housings, respectively, and engaged by the pair of push rods, respectively.

Abstract: A saddle block assembly including a main body having a shipper shaft opening through the main body bottom end, and an eccentric pin opening in the main body top end, an eccentric pin received in an eccentric pin opening in the top end of the main body, and a wear plate support. The wear plate support has a pin receiving opening, the eccentric pin being received in the pin receiving opening. Wear plates are mounted on the bottom end of the wear plate support and are adapted to bear against the top of a dipper handle.

Abstract: This invention discloses highly scalable and modular automated optical cross connect switch devices which exhibit low loss and scalability to high port counts. In particular, a device for the programmable interconnection of large numbers of optical fibers (100's-1000's) is provided, whereby a two-dimensional array of fiber optic connections is mapped in an ordered and rule-based fashion into a one-dimensional array with tensioned fiber optic circuit elements tracing substantially straight lines there between. Fiber optic elements are terminated in a stacked arrangement of flexible fiber optic circuit elements with a capacity to retain excess fiber lengths while maintaining an adequate bend radius. The combination of these elements partitions the switch volume into multiple independent, non-interfering zones, which retain their independence for arbitrary and unlimited numbers of reconfigurations.

Abstract: This invention relates to a system for efficiently transporting large quantities of initially loose pieces of irregularly shaped scrap sheet metal by temporarily compressing batches of such pieces together into unitary slabs and then forming stacks of numerous slabs, arranged in closely fitted rows within open-top railroad cars or truck trailers. Each slab is formed by ramming a batch of pieces against a vertical plate so that the slab is generally vertically arranged. The slab is then allowed to gravity-fall upon a downwardly tilted table. A second slab is formed and similarly allowed to fall on the table in end-to-end contact with the first slab. The table is then tilted into a horizontal position. A horizontal magnet is positioned to overlap and engage both slabs simultaneously. The magnet is supported by a crane which lifts and moves the magnet over the open-top railroad car or truck and deposits the pair of slabs into an adjacent pair of stacks.

Abstract: The invention relates to an excavation machine comprising: a mast having a longitudinal direction; a bar presenting a first end provided with an excavation tool; and a carriage movable along the longitudinal direction of the mast and including a first holder member for holding the bar relative to the carriage, said carriage being suitable for moving the bar along the longitudinal direction of the mast. The invention is wherein the first holder member is pivotable relative to the carriage and by the fact that the first holder member presents a locked state in which the bar is prevented from moving in translation relative to the carriage, and an unlocked state in which the bar is free to move in translation relative to the carriage.

Abstract: A workpiece transfer robot system including a machine tool provided with a workpiece support section and a robot capable of transferring a workpiece relative to the workpiece support section of the machine tool. The machine tool includes a cover surrounding at least the workpiece support section. The cover includes a first side wall provided with a first opening usable for a workpiece transferring task of the robot.

Abstract: A robot includes a base member, which is installed at a position offset from the front of a door of a machine tool to the side, as viewed in a direction vertical to the surface where the door is provided and is fixed to a surface of a base slanted so as to face the door side. A rotary member is coupled to the base member so as to be rotatable about a first axis extending vertical to the slanted surface. A first arm member is coupled to the rotary member so as to be able to swivel about a second axis vertical to the first axis, and a second arm member is coupled to the first arm member so as to be able to swivel about a third axis parallel to the second axis.

Abstract: The processing system (10) serves for processing a moving workpiece (12) by means of an industrial robot (16) that can be rigidly coupled, intermittently, to the workpiece (12) and/or to a movable workpiece carrier unit (14), the industrial robot (16), when in a decoupled operating position (42), being carried by a carrier device (18) that is movable, independently of a workpiece, by means of a drive unit (20) acting with active drive, and, when in a coupled operating position (44), being floatingly mounted relative to the carrier device (18) by means of a floating bearing system (22).

Abstract: An automated hunting blind which includes a platform operable to be always maintained in a generally horizontal position. The blind includes a base which is secured in an elevated position with a tree trunk. A boom is pivotally connected with the base and the platform. A drive and a control are provided to move the platform between a down position and selected elevated positions.

Abstract: A machine tool is provided for processing a workpiece, e.g., a metal sheet. The machine tool comprises at least one support configured to, in a support position, support a part of the workpiece on an upper surface, the part being completely separated from the workpiece, and a motion unit for moving the support downwards out of the support position into a discharge position located underneath the support. The motion unit is configured to accelerate the support, at least in a region of the part lying thereon, out of the support position along a gravitational direction with an acceleration which is greater than an acceleration of the part in the gravitational direction, and to move the accelerated support into an open position located outside a path of movement of the part at a speed such that the workpiece part attains the discharge position in free fall.

Abstract: A vehicle of the industrial truck type comprises a chassis (3), at least three wheels (4) arranged to support the chassis while resting on the ground and a lifting unit (8) connected to the chassis having one or more members (9) arranged to carry loads and a power arrangement to raise and lower the load-carrying members relative to the chassis. The lifting unit is carried by the chassis via a mast-like beam (12), that is pivotably connected to the chassis about a substantially horizontal axis. Power means is arranged to pivot the beam about this axis relative to the chassis.