Abstract: A method for handling of an offshore wind turbine component includes using a vessel having a hull on which a motion compensating crane is mounted. The crane includes a main boom; a main boom luffing assembly; a mobile hoist cable suspension member; and a hoist winch and a hoist cable driven by the hoist winch. An object suspension device is suspended from the hoist cable. The mobile hoist cable suspension member is supported by a motion compensating support device that is fitted to the tip end of the main boom, the motion compensating support device including one or more motor powered motion displacement actuator assemblies and a motion compensating support device controller. The method includes connecting the offshore wind turbine component to the object suspension device; and operating the motion compensating support device to provide motion compensation in at least one direction of the object suspension device and the connected offshore wind turbine component.

Abstract: A rubber-tired gantry crane (RTG) includes an energy storage device disposed on and configured to provide power to the RTG, a primary charging device disposed on the RTG and configured to charge the energy storage device, and a secondary charging device disposed on the RTG and configured to charge the energy storage device when the RTG is idle or not in operation.

Abstract: A system and method for mounting a Closed-Mouth Power Tong on a Well Servicing Rig in order is disclosed. The power tong can be operated remotely when making up or breaking out connections on oilfield tubing. The system utilizes an assembly that can lift and lower the tong to the appropriate height as required to engage the threads on the tubing. The assembly is connected to the blowout preventer or wellhead with a quick connect system that is adjustable for various angles so that the tong can be utilized in various positions to run tubing into, or out from, the well center unhindered.

Abstract: Provided is a vehicle that elevates a working beam installed between a pair of booms with a working beam elevating unit and can ensure the area of a load receiving surface where a load is loaded. The working beam elevating unit is received in a working beam and one end of a chain is fixed to a boom. Therefore, the working beam is moved up/down by loosening and retracting the chain. Therefore, as the working beam elevating unit is installed at the working beam, it is not necessary to ensure a space for installing the working beam on a vehicle body. Therefore, it is correspondingly possible to enlarge the space (area of the load receiving surface) on the vehicle for loading a load.

Abstract: In one aspect of the disclosure, a cylinder-driven lifting mechanism of a compaction machine includes a cylinder having a first end and a second end, a fixed pulley set, a movable pulley set, a rope having a head end, and a tail end configured to connect a compaction hammer. The first end of the cylinder is connected to a vehicle body of the compaction machine and the second end of the cylinder is connected to the movable pulley set. The rope is wound on the fixed pulley set and the movable pulley set and is then connected to the compaction hammer. When the cylinder performs extension and refraction movement, the movable pulley set moves with the cylinder, the distance between the movable pulley set and the fixed pulley set increases or decreases, and the compaction hammer connected to the tail end of the rope is lifted up or dropped respectively.

Abstract: A container loading system has a hoist frame with a movable carriage. A pair of single stage cylinders moves the carriage between positions. The carriage includes at least two rotatable sheave to receive a cable. The cable has a free end to attach with a container. The movement of the cylinders moves the carriage between positions to load or unload a container onto or from the container loading system.

Abstract: A counterweight loading and unloading device and a movable crane have a freestanding pallet (10) with two ends whose upper end faces are used for holding a counterweight (61). The two ends of the freestanding pallet (10) are both equipped with a cavity, and at least one telescopic oil cylinder (11, 12, 13, and 14) is provided in the cavity. A fixed end of the telescopic oil cylinder is fixed with the freestanding pallet (10), and a telescopic end of the telescopic oil cylinder is coupled with a pallet lifting mechanism for lifting the freestanding pallet. The device is not limited by a planar space of a vehicle frame and a turntable height of the movable crane. An integral dimension of the movable crane is not increased, thus preventing integral dimension of the movable crane from exceeding a road traveling standard. The structure of the device is more compact, and the telescopic oil cylinder plays a role of the counterweight, thus enabling stress of the turntable to be more reasonable.

Abstract: Disclosed is a vehicle mounted winch and cable assembly that may include a slide track, a winch, a cable guide and a powering means. Also disclosed is a related method. The slide track may be rigidly mounted to the vehicle and may have a track axis extending generally perpendicular to a longitudinal axis of the vehicle. The winch may be rigidly mounted to the vehicle for accepting and discharging the cable. The cable guide may be movably secured to the slide track and may accept the cable from the winch and then redirect the cable from a direction generally parallel to the track axis to a direction generally perpendicular to the track axis. The powering means may adjustably move the cable guide along the slide track.

Abstract: A crane comprising a boom formed as an elongate tubular structure and a line assembly to extend a line from a least one end of the boom. The line assembly may include a first bank of sheaves, a second bank of sheaves, a line reeved around the first and second banks of sheaves, and an extension mechanism controlling the distance between the first and second banks of sheaves. The second bank of sheaves and at least a portion of the extension mechanism being enclosed within boom.

Abstract: A telescoping workover rig is characterized by a derrick having a bottom mast section mounted on a base or carrier and a top mast section telescopically fitted in the bottom mast section. In functional configuration a system of tram sheaves mounted on movable trams and connected to opposite fixed stationary sheaves by a continuous cable, serve to raise and lower a travelling block suspended by the cable from travelling block sheaves and crown sheaves in the extended top mast section. The trams that mount the tram sheaves are fitted to the ends of one or a pair of cylinder rods extending from a corresponding tram drive cylinder or cylinders.

Abstract: An elevator includes a special propelling fluid dynamic device which uses as a plunger the duly balanced car counterweight. The car conveys people and things upwards and downwards within a vertical conduit or hoistway supported by a cable extending to an upper pulley. When changing the direction, a counterweight is extended to balance the car. The pulley is supported from the hoistway walls and is kept in a freely-rotating condition while the balanced counterweight is a hollow piston-counterweight, accommodated in the cylinder vertically disposed in the hoistway itself and adjacent to the car. Both are integral with the propelling fluid dynamic device that produces the upward and downward movements of the car, which is completed with a circuit having a fluid flow conduit and a driving pump coupled to the valve mechanism.

Abstract: A vehicle (10) is used to lift the buried lid of a crypt and any soil or turf overlying the lid. The vehicle (10) has a mobile frame (14) which can be positioned over the lid. An attachment frame (11) is suspended from a subframe (12) within the mobile frame (14), the subframe (12) being adjustable laterally relative to the frame (14). The attachment frame (11) has winch cables (19) adapted to be connected to respective attachment fittings on the lid. Hydraulic cylinders (13) are used to raise the attachment frame (11) relative to the mobile frame (14), and thereby lift the lid and any overlying soil/turf. The raised lid can be transported while suspended from the vehicle (10), and subsequently returned for replacement on its crypt in a reverse procedure.

Abstract: A method and apparatus for replacing old, in-ground hydraulic elevator lift cylinders in which a portable tower is erected within the elevator hoistway and a shoring sleeve of larger diameter than the old cylinder is secured to a head plate slidably mounted for vertical movement on the tower and facing downwardly. After loosening the hoistway floor and subsoil surrounding the old cylinder, a drive mechanism such as a winch or hydraulic jack is actuated to lower the shoring sleeve into the ground to surround the old cylinder. The head plate is then attached to the old cylinder, and the drive mechanism is actuated to lift the head plate and cylinder upwardly until the cylinder is raised completely out of the ground. The old cylinder is discarded, and a new cylinder is attached to the head plate and lowered into the area surrounded by the shoring sleeve.

Abstract: A hoisting apparatus for a straddle carrier having a spreader with a frame part having a plurality of lifting points, a plurality of hoisting cables each having a first and second end, a top frame having a hoisting mechanism and a first set of cable pulleys. The hoisting mechanism includes a lifting cylinder and a piston movably arranged within the lifting cylinder, and a second set of cable pulleys mounted onto the top frame, such that the second set of cable pulleys is driven by the extension of the piston and the hoisting cables are passed over the first set of cable pulleys and the second set of cable pulleys, respectively. The second end of the hoisting cables is connected to the hoisting mechanism wherein upon extension of the piston out of the lifting cylinder produces a lifting movement that is of an equal magnitude for each of the plurality of hoisting cables.

Abstract: The present invention relates to a riser-tensioner for exerting a tensile force from a drilling vessel or drilling platform upon a riser, comprising a riser ring which is for fastening attachably to the top end of the riser, and one or more cables extending by way of cable pulleys from said vessel or platform to said riser ring, in which said cable pulleys are under such influence or tensioning means that a tensioning force can be applied to the cable, the riser ring being provided with riser ring sheaves and the cables being guided in an outgoing reeving from the vessel or the platform to said riser ring sheaves, and being guided back by way of said riser ring sheaves in a return reeving to said vessel or platform.

Abstract: A mounting apparatus for a piston-cylinder arrangement (10,11) in a derrick (1) placed on a drill floor (2), which hydraulic piston-cylinder arrangement (10,11) is adapted to raise and lower a yoke (8) which travels on guide rails (7) in the derrick (1) itself, where the cylinder (20) is firmly held by a mounting apparatus (31) in relation to the drill floor (2). For the changing of gaskets (27) on the piston (21) and the cylinder (20), the cylinder is arranged so as to be lowerable in relation to the mounting thereof. The mounting apparatus (31) is designed to be releasable and comprises a flange (32) permanently mounted on the cylinder (20), a fixing device (37) in fixed position in relation to drill floor (2), a dividable locking ring (34), and a locking device (32) and the fixing device (37) and being firmly held in engagement with the aid of the locking device (38). A method of changing gaskets on a piston and cylinder is also described.

Abstract: An apparatus for a derrick, comprising two or more hydraulic piston-cylinder arrangements (10, 11) for raising and lowering a yoke (8) which travels on guide rails (7) in the derrick (1) itself, where two or more wire lines (13) are strung over sheaves (12) rotatably attached to the yoke. The wire lines (13) are attached at one end thereof to the top drive (9) and at the other end thereof are secured to an attachment point (14a, 14b) adjacent to a drill floor (2), said two or more wire lines being run in two sets (13a, 13b) of lines. The attachment points (14a, 14b) for each wire set are connected to a tension equalizer assembly to equalize differences in tension in the wire lines.

Abstract: The disclosure relates to a vertically operating linear actuator for a multi-stage extendible column for carrying a cinematograph or TV camera. A load representing the weight imposed by the multi-stage column with its camera is indicated at (10), a vertically extending gas strut at (11) and a base (12). A piston rod (15) of the strut carries a rotatable disc mounted on a pivot pin eccentrically to its geometric center to provide a varying radius of rotation between the offset center and disc periphery (21). A tether (22) extends over the disc and is secured at one end to an anchorage (23) on the base and the other end supports the load (10). The effective force applied by the strut to the weight (10) will be determined by the effective radii of the disc (20) at points where the tether engages the disc.

Abstract: Apparatus and method for lifting blowout preventers beneath the floor of a drilling rig are provided. More than one cable is used on the drums of winches, allowing the winches to be compact enough for use on a drilling rig floor while avoiding the requirement for larger cable that would be required to achieve the high safety factors needed. The cables or wire ropes on the winches are attached to a member from which a larger diameter, higher strength intermediate cable is also attached. The intermediate cable is then attached to known apparatus such as a cradle for lifting a blowout preventer stack.

Abstract: A hydraulically-operated hoist is disclosed. The hoist includes a plurality of hydraulic piston/cylinder arrangements, each having an upper end. Two guide rails are disposed in parallel with the hydraulic piston/cylinder arrangements. A self-aligning yoke is connected between the upper ends of the hydraulic piston/cylinder arrangements and is raised and lowered along the two guide rails by the hydraulic piston/cylinder arrangements. The yoke comprises a beam with the two ends. An arm is connected to each end of the beam, extends obliquely upward from the beam, and terminates in a remote end rotatably connected to the upper ends of the hydraulic piston/cylinder arrangements. At least two sheaves are rotatably connected to the beam, each of which are capable of running its own wire line.

Abstract: A cable retraction speed limiter has a body which is designed to be mounted on the housing of a hoist and a spool which is rotatably supported by the body. A flexible extension member is disposed about the spool so that it can be extended from and retracted onto the spool by rotation of the spool. The end of the flexible extension member is designed to be attached to an air pressure responsive member inside of the air balancing hoist. The cable retraction speed limiter also includes a spool lock that stops rotation of the spool when the rotational speed of the spool exceeds the rotational speed limit, thereby limiting the hoist cable retraction speed.

Abstract: A lifting apparatus for lifting a heavy object. The lifting apparatus including a frame assembly having a pair of side beams spaced parallel to one another. A sliding sheave assembly is mounted to the frame assembly. The sliding sheave assembly is positioned between the pair of side beams. The sliding sheave assembly has a first shaft with a plurality of first sheaves mounted thereto and a second shaft with a plurality of second sheaves mounted thereto. The first and second shafts are separated by a distance which can be varied A cylinder has a first end connected to the frame assembly and a rod end attached to the sliding sheave assembly. The cylinder rod end is capable of moving longitudinally relative to the first end to hereby alter the distance between the first and second shafts. A cable having first and second ends attached to the frame assembly is reeved between the pluralities of first and second sheaves.

Abstract: A lifting apparatus for lifting a heavy object. The lifting apparatus including a frame assembly having a pair of side beams spaced parallel to one another. A sliding sheave assembly is mounted to the frame assembly. The sliding sheave assembly is positioned between the pair of side beams. The sliding sheave assembly has a first shaft with a plurality of first sheaves mounted thereto and a second shaft with a plurality of second sheaves mounted thereto. The first and second shafts are separated by a distance which can be varied. A cylinder has a first end connected to the frame assembly and a rod end attached to the sliding sheave assembly. The cylinder rod end is capable of moving longitudinally relative to the first end to thereby alter the distance between the first and second shafts. A cable having first and second ends attached to the frame assembly is reeved between the pluralities of first and second sheaves.

Abstract: A tree compressing and binding apparatus has particular usefulness in handling of Christmas trees, employs a hydraulic power system which utilizes the even stroke of one or a plurality of hydraulic cylinders to drive a tree through a loader funnel. The apparatus is capable of being used in harsh weather environments and provides a low cost mechanism for packaging trees either for point of sales use or for large scale harvesting and shipping jobs.

Abstract: A winch includes a cylinder containing a movable piston to which are respectively mounted a fixed and a movable pulley assembly around which a line to be pulled is entrained. The pulley assemblies are located within the working chamber and the line enters the cylinder through one end formed remote from the chamber and through a one way brake mounted to that remote end. The brake permits line to enter the cylinder as the working chamber is pressurized to move the piston and thereby the movable assembly towards the remote end. The one way brake prevents line from exiting the cylinder at this location. The line extends slidingly through the piston and may exit the cylinder at the opposite end thereof which is also equipped with a one way brake which prevents line from entering the cylinder but allows the line to exit the cylinder. End of stroke positions of the piston are sensed by means of Hall Effect Sensors to control pressurization and venting of the working chamber through a three way valve.

Abstract: The invention enables owners of backhoes and similar equipment to use their machines either as a backhoe or as a crane with only minor modifications. The invention provides an attachment for a backhoe that takes advantage of existing hydraulic pistons on the backhoe as the lift implement for the crane.

Abstract: A spray gun reciprocating device has a pair of tracks which are parallel to one another, each track comprises the surfaces of a square tube which are engaged by independently rotatable rollers of each of at least three roller assemblies, the rollers of each assembly having track engaging surfaces which converge towards one another, and the rollers are freely rotatable so that if one roller engages a track surface closely to its axis of rotation with the other roller, there is no skidding of the engaging surfaces.

Abstract: A three-chamber jack employs a telescoping relation between an outer cylinder and an intermediate cylinder, the closed outer ends of which cylinders continuously sustain lifting-load force. An annular piston is fixed to the inner end of the intermediate cylinder and has sealed sliding engagement to the bore of the outer cylinder. An inner cylinder is fixed to the closed outer and of the outer cylinder and extends concentrically within both the outer and the intermediate cylinder, and the inner cylinder has sealed sliding engagement with the bore of the annular piston. Three internal volumes are thus defined. Load-counterbalancing gas pressure is continuously operative within the first of those volumes, over the entire area of the annular piston, and hydraulic fluid contained within the second and third volumes is reversibly pumped from one to the other of the second and third volumes, to reversibly determine piston displacement.

Abstract: An improved drilling rig which is mounted on a trailer to be transported from one location to another. The drilling rig includes a hoist for raising and lowering equipment, the hoist including hydraulic cylinders and a pair of cables. One end of each cable is connected to a base and the opposite end of each cable forms an equipment end portion which is connectable to the equipment to be raised and lowered, a portion of each cable being moveably connectable to a portion of the hydraulic cylinders. Portions of the hydraulic cylinders are moveable to raised and lowered positions for raising and lowering the equipment end portions of the cable and the equipment connected thereto.

Abstract: A post frame machine for applying pulling forces to a damaged automobile comprises two vertical support posts fixedly mounted on a base frame, a hydraulically operated cylinder disposed in each of the posts, and a load chain and pulley arrangement for exerting the pulling force. The cylinders are independently operable to allow different forces to be applied at closely adjacent location on the automobile. The apparatus further includes chain locks for securing the load chains.

Abstract: The invention in a preferred embodiment contemplates a dual-lift hydraulic arrangement in which each of two hydraulic-lift systems employs a power integrator in the connection between a charged hydraulic accumulator and a hydraulic actuator for cable suspension of a load. The accumulator may be a single device serving the respective hydraulic systems, each of which terminates in a traction cylinder for operating a cable lift for its end of the load suspension. A single prime mover serves both power integrators, and the pressurized charge of the accumulator is advisedly set to accommodate (counterbalance) a predetermined average of the combined load on the two actuators. The arrangement lends itself to single-handed control of both hydraulic systems and to the corrective tilt orientation of a load which may be relatively heavy at one end and relatively light at the other end.

Abstract: A work desk has an adjustable height working surface that is raised by a force applied by a lockable gas spring via a first pulley system. The first pulley system doubles the travel of the working surface as compared with the travel of the piston of the gas spring. A second pulley system ensures that all parts of the working surface are raised by an equal amount. Four slides guide the movement of the working surface. The combination of the slides and second pulley system allows the working surface to be closely held with a minimum of lateral or vertical play when the gas spring is locked. The first pulley system, in conjunction with a commercially available gas spring, the travel of whose piston is limited to 71/2 inches (190 mm), permits a vertical travel of 15 inches (380 mm) for the working surface. This travel is adequate to permit a broad range of operators to use the work desk while working in either a sitting or a standing position.

Abstract: An apparatus for balancing tongs is comprised of a pair of fluid actuated piston and cylinder assemblies. The rod of each assembly carries a first pair of rotatably mounted pulley wheels, and a second pair of pulley wheels is mounted on the assembly in spaced relationship to the first set of pulley wheels. A cable is journalled around the pulley wheels, suspended over an elevated pulley and attached to a hydraulic tong for counterbalancing, lifting and lowering the tong. A bleed line permits fluid to escape from the cylinder as the hydraulic tong moves downwardly with a workpiece.

Abstract: A hydropneumatic cable tensioner is comprised of an enclosed cylinder featuring a plurality of annular chambers. A fixed cable sheave is mounted to one end of the cylinder. A movable cable sheave is mounted to a piston rod connected to a piston which reciprocates in a piston bore chamber of the cylinder. Regulated compressed gas is connected to the outer accumulator chamber of the cylinder thereby exerting high pressure forces on oil found in the middle or high pressure oil chamber of the cylinder. Pressurized oil forces a piston to move outwardly thereby increasing the distance between the two sheaves and tensioning a cable and containment chamber within the piston rod. Restriction ports between the piston bore chamber and the containment chamber within the piston rod regulate movement of the piston and prevent uncontrolled acceleration should a cable failure occur.

Abstract: Well derrick in which the travelling crown block is operated by hydraulically operated linear actuators and a travelling block is operated by special reeving, the arrangement advantageously being such that the loads being handled bypass the tower of the derrick so that the cost of the tower can be reduced. The reeving system results not only in uniform and symmetrical force distribution relative to the crown block and travelling beam but also in a travel of the travelling beam twice the stroke of the linear actuators.

Abstract: A hydropneumatic cable tensioner is comprised of an enclosed cylinder featuring a plurality of annular chambers. A fixed cable sheave is mounted to one end of the cylinder. A movable cable sheave is mounted to a piston rod connected to a piston which reciprocates in the innermost or piston bore chamber of the cylinder. Regulated compressed gas is connected to the outer chamber of the cylinder thereby exerting high pressure forces on oil found in the middle or high pressure oil chamber of the cylinder. Pressurized oil forces a piston to move outwardly thereby increasing the distance between the two sheaves and tensioning a cable. Restriction means within the piston bore chamber regulate movement of the piston and prevent uncontrolled acceleration should a cable failure occur.

Abstract: A cylinder driven reciprocator uses a block and tackle output to broaden the mechanical range of the cylinder. The output force, speed, and travel distance depends upon the number of moveable pulleys between a fixed reference point and the output attachment on the cable.

Abstract: A power-up and power-down mast and carriage assembly for a lift truck of the type having a stationary mast section fixed to the truck, a movable inner mast section reciprocable within the stationary mast, a fork carriage movably associated with the inner mast section, a double-acting hydraulic ram having an extensible and retractable cylinder and piston rod assembly operatively connected between said mast sections for extending and retracting the inner mast section relative to the stationary mast section. Lost-motion couplings interconnect both power-up and power-down chains with the stationary mast and carriage in a closed loop chain rigging system. The lost-motion couplings each have a rod slidably through the interconnection with the carriage and stationary mast, and spaced stops operable to limit travel of the rod to a predetermined distance.

Abstract: A stationary upright frame is arranged to be mounted on the rear of a tractor and has a horizontal axis fair-lead drum over which choker cables from the drive drum of the tractor are reeved. The horizontal axis fair-lead drum is slidably supported in the upright frame for vertical adjustment by fluid operated cylinders whereby the drum can be moved from a low center of gravity position to an elevated position which holds the choker cables up off the ground.

Abstract: A hoist comprises a housing carrying a fixed and slidable sheave set which are engaged by a rope. A piston and cylinder combination are connected to the slidable sheave set for moving it and thus moving a load connected to the rope. The piston has a threaded rod connected to the displaceable sheave set which carries a threaded nut. The axial movement of the nut is restrained by a sleeve which permits rotation of the nut with axial movement of the rod. If the axial movement of the rod accelerates above a selected limit, for example when the load is abruptly removed from the rope, the nut moves against a friction surface in the sleeve to brake the rotation thereof and thus brake the axial movement of the rod.

Abstract: Hoist mechanism for a truck vehicle of the type having a pivotally movable load support frame. Opposed piston hydraulic cylinders are carried by the load support frame. Each of the hydraulic cylinders has a piston rod to which is attached a rotatable sheave. Another sheave is rotatably attched to the load support frame. A cable has one end thereof attached to the load support frame. The cable has portions in engagement with the sheaves and has a free end adapted to be attached to a load. A load is thus drawn upon the load support frame as the hydraulic cylinders are operated.

Abstract: Apparatus (10) for lifting or moving loads require high operator visibility and simplicity of construction. For example, in a mast assembly (10) such as can be used on a fork lift truck or other cargo handler it is desirable to maximize visibility through spaced-apart uprights (16,18,24,26). Also, free lift of a carriage (14) which engages the load will maximize visibility in that the movable uprights (16,18) will not be elevated above the fixed uprights (24,26) when raising the carriage (14) to move the load. In the apparatus (10), first and second lifting elements (32,34) or jacks (36,38) are mounted adjacent the uprights (16,24;18,26) for visibility. The lifting elements (32,34) are interconnected by a load sharing member (48) for free lift and to distribute the forces encountered in raising the load more equally between the lifting elements (32,34) and the chains (52', 52").

Abstract: A control system for stabilizing a body suspended by a flexible line from a structure such as a ship, which is subject to uncontrolled oscillating movements, such as may be caused by wave motion, incorporates a winch (3) to which the line is attached, a pulley (4) over which the line (2) passes and from which the body is suspended, and a loop in the line between the winch and pulley, an accelerometer (28) being located adjacent the pulley, and the length of the loop being altered in controlled response to a stabilizing signal formed by combining signals derived from the accelerometer, and from the measured amplitude of oscillations of the loop length, and modified by a compensating signal to compensate for the effect of friction in the system.

Abstract: As part of a well derrick system using pair of elongated hydraulic cylinders mounted on the derrick face for well pipe elevating, in which an equalizer beam bridges the cylinder ram heads to maintain equality of advance of the rams, the beam being pivoted on a horizontal pivot above the ram heads, the beam carries a lower centrally aligned horizontal pivot sheave means from which cable means extend downwardly to suspend a travelling beam from which depend any of various pipe manipulating tools. In some species additional sheave means on the travelling beam and on an intermediate fixed beam provide for multiple wrappings of the cable means whereby force or distance multiplication may be obtained.

Abstract: Improved means for suspending a drill string using a pair of hydraulically actuated belts is disclosed. A derrick or tower is mounted to a base to overlie a standard rotary drill table. The drill string (comprising a number of drill pipes and a drill collar) and a drill bit are suspended within the hole being drilled by a hook. A hook support rides between a pair of vertical guide rails and supports the hook between the rails via a pair of belts which engage the hook support. The belts extend from the hook support, to the stationary pulleys at the top of the tower, and down to an alternating series of stationary and movable pulleys which define a variable length path along which the belts are guided. When it is desired to raise or lower the hook, and therefore the drill string therefrom, the hydraulically actuated, movable pulleys are either raised or lowered to change the length of the variable length path and consequently the length of belt along the path.

Abstract: An apparatus (10) for processing trees includes a hollow boom structure (12), a processing head (14) mounted for movement along the boom and an actuating cylinder assembly (38) which is mounted inside the boom structure. The cylinder includes a body member (50) and support means (52) engageable with the inside of the boom which support the body member for linear movement along the boom. A reeved cable system interconnects the actuating cylinder assembly with the processing head such that the actuating cylinder and the processing head move in opposite directions along the boom when the actuating cylinder is pressurized. In accordance with one aspect of the invention, the cylinder assembly includes opposed piston assemblies (40, 42) and means associated with the piston rod (54) of one piston assembly (40) for selectively transferring hydraulic fluid from a source to the head ends of both piston assemblies and to a central chamber (60) defined between the piston assemblies.

Abstract: A new and improved portable hydraulic rig for performing workover, drilling or other operations on a well, usually a petroleum well, wherein the rig has a telescoping mast for telescoping to a reduced length for transportation, wherein the mast is cantilevered in use so that the travelling block moves vertically at one side of the mast, wherein the cable for the travelling block is reeved over the various sheaves including a sheaves on a hydraulic power assembly with the dead end of the line being fastened at or in proximity to the rig floor for balanced loading on the legs of the mast and to enable slack in the cables to be taken up when telescoping the mast.

Abstract: A load moving apparatus in which a linear actuator is used to move a load through an arrangement of cables and pulleys, so that the load is moved through a distance and at a speed which is a multiple of the distance of movement of the linear actuator.