Abstract: A hoisting system of this disclosure includes a drawworks, a crown block or a compensator, a traveling block and at least one sheave assembly connected to the crown block or compensator in “Low Load/High Speed” mode and connected to the traveling block in “High Load/Low Speed” mode. A method to lift a load using a hoisting system of this disclosure uses a drawworks, a crown block or a compensator, a traveling block and at least one sheave assembly connected to the crown block or compensator in “Low Load/High Speed” mode and connected to the traveling block in “High Load/Low Speed” mode.

Abstract: A lifting crane having a jib and a lifting device with double reeving configured to distribute and lift a load along the jib, wherein the lifting device is reversibly configurable between two reeving configurations including a single reeving configuration with two lifting strands and a double reeving configuration with four lifting strands. The lifting device includes a reeving change system for performing a reeving change between the single reeving configuration and the double reeving configuration, and vice versa. The lifting crane further includes a system for automated determination of the reeving configured to automatically determine the reeving configuration between the single reeving configuration and the double reeving configuration.

Abstract: A bottom block assembly includes a bottom block defining a cavity and at least one opening passing through a portion of the bottom block. The assembly further includes a plurality of sheaves disposed at least partially within the cavity, each sheave having a central opening. The assembly further includes a sheave pin passing through the at least one opening in the bottom block and the central openings in the sheaves to rotatably couple the plurality of sheaves to the bottom block. The assembly further includes a plurality of captivating frame assemblies to be coupled to the plurality of sheaves, each of the plurality of captivating frame assemblies including a housing and a plurality of rollers rotatably mounted to the housing. Each captivating frame assembly is associated with a corresponding one of the sheaves. The assembly further includes a plurality of wires for coupling the plurality of captivating frame assemblies to the plurality of sheaves.

Abstract: In an exercise apparatus incorporating a vibration pulley system, a vibration unit connected to the frame of the exercise apparatus. The vibration unit may include a toothed pulley and a contact roller mounted on a bracket. A pulley cable may include an end fixedly secured to the frame of the exercise apparatus. The pulley cable may be threaded about the toothed pulley and the opposite end of the pulley cable connected to a handle that may be grasped by an operator. The toothed pulley may be in engagement with the contact roller to generate vibrations that may be felt by the operator. The vibration intensity may be adjusted to variable levels.

Abstract: There is provided a mast for a rig, comprising a main boom having a lower end adapted for pivotal connection to a mast support of the rig; and a mast stop extending from the main boom. In use, the mast pivots between a stowed condition and an erect condition, and the mast stop abuts the mast support at a position spaced from the lower end, when the mast is in the erect condition.

Abstract: There is described a device for removing a drawer-type hopper of a railroad car, the device comprising: a first support base positioned on a platform and a second support base supported on the railroad car; and a tackle fastened on the first support base; the tackle comprising a first hook associated to the drawer-type hopper, the first hook and the drawer-type hopper being moved linearly by the tackle in the opposite direction of the railroad car.

Abstract: A hoisting device includes a hoisting cable, a winch, a crown block and a traveling bottom block provided with a load attachment device. Both the crown block and the traveling bottom block include one or more sheaves having an essentially horizontally extending rotation shaft about which sheaves the hoisting cable is reeved. At least some of the traveling bottom block sheaves are associated with a releasable connector, and are thereby detachable from the load attachment device and displaceable to an inoperative position. The rotation shaft of multiple traveling bottom block sheaves and multiple crown block sheaves is essentially perpendicular to the rotation shaft of remaining multiple traveling bottom block sheaves and remaining multiple crown block sheaves.

Abstract: A vertically folding wall partition with a set of foldable panel assemblies serially and pivotally connected through a series of vertically spaced apart supports, and a moving mechanism varying a distance between opposed ends of each panel assembly following a downwardly progressing sequence starting with the uppermost panel assembly as the panel assemblies are moved from the deployed position to the folded position, and the moving mechanism varying the distance between the opposed ends of each panel assembly following an upwardly progressing sequence starting with the lowermost of the panel assemblies as the panel assemblies are moved from the folded position to the deployed position.

Abstract: A hoisting assembly for lifting or lowering a heavy object includes an upper fixed block, an upper movable block being suspended from the upper fixed block by at least one first rope which is reeved into one or more first rope lengths between the upper fixed block and the upper movable block, a lower movable block being connected to the upper movable block by at least one second rope which is reeved into one or more second rope lengths between the upper fixed block and the upper movable block. The first and second ropes are reeved in such a way that in use the upper movable block can be positioned at a distance greater than zero from the upper fixed block and at a distance greater than zero from the lower movable block by controlling the lengths of the first and second ropes.

Abstract: A lifting block and a method of using it for supporting a load (8) from a first lifting device (2) or sharing the load between the first lifting device (2) and a second lifting device (3), particularly for use on a vessel (1) and deep water applications. The lifting block (7), with at least one sheave (10), has first and second connection elements (14, 15) associated with it. In one arrangement (single fall) a lifting wire or rope (4) is fed around the sheave (10) and terminated in an end stop (14) which also provides the first connection element. When the first lifting device (2) is operated alone, the end stop (14) rests on the block (7). When the second connection element (15), secured to the lifting wire or rope (5) of a second lifting device (3), is joined to the first connection element (14) the load is snared between the two lifting devices (2, 3) which can then be operated in unison to position the load at a required, deeper position.

Abstract: A load equaliser for supporting a drag line bucket from first and second cables is disclosed. The load equalizer has a main body having a central portion and side portions providing respectively first and second clamps for clamping end portions of the first and second suspension cables. A rotatable mounting is provided in the suspension central portion of the main body. A link body is suspended below the main body and connected thereto through the rotatable mounting whereby freedom of relative rotational motion is provided at least about an axis substantially at right angles to the direction between the clamps. The rotatable mounting is in a zone extending substantially between the clamps.

Abstract: Embodiments of the present invention provide pulley apparatuses that can be easily incorporated into block-and-tackle configurations. In some embodiments, a rope can be easily dropped into place and removed, rather than having to be threaded in. For example, the pulley housing can include a rope channeling structure near the end opposite the aperture, and the rope channeling structure can facilitate introducing the rope into engagement with the wheel and/or removing the rope from engagement with the wheel. In some embodiments, the rope channeling structure can prevent the rope from inadvertently becoming removed from the pulley. Some pulley apparatuses can comprise a minimal number of parts, which can significantly simplify the manufacturing process and provide for a more consistent final product.

Abstract: The invention relates to a combination double bottom hook block in which two pulley blocks (2, 3) each with a plurality of pulleys are connected to one another by means of a rocker (1), a load hook being mounted in a pivotable manner on the rocker. If use is made here of two lifting cables, each of these lifting cables is led over a pulley block (2, 3) and, in order to achieve the same loading capability if use is made of just one lifting cable, the latter is led, in addition, over a floating pulley (2) which is mounted between the two pulley blocks (2, 3), the two pulley blocks (2, 3) also being secured against tilting.

Abstract: Embodiments of the present invention provide pulley apparatuses that can be easily incorporated into block-and-tackle configurations. In some embodiments, a rope can be easily dropped into place and removed, rather than having to be threaded in. For example, the pulley housing can include a rope channeling structure near the end opposite the aperture, and the rope channeling structure can facilitate introducing the rope into engagement with the wheel and/or removing the rope from engagement with the wheel. In some embodiments, the rope channeling structure can prevent the rope from inadvertently becoming removed from the pulley. Some pulley apparatuses can comprise a minimal number of parts, which can significantly simplify the manufacturing process and provide for a more consistent final product.

Abstract: The invention comprises an anchor, rope and pulley system to load and unload cargo into and out of passenger vehicles. The anchor system comprises two load bearing straps and a means to attach the straps together. The straps are looped around the vehicle's side handle grips. The looped straps attach to each other near the center of the cargo area. The rope and pulley system comprises a rope, a large pulley, a small pulley, a means to attach the rope and pulley system to the anchor system, a means to attach the cargo to the rope and pulley system, and a means to clamp the rope to create a handle. Cargo can be lifted into a vehicle by pulling the handle with one hand and guiding the cargo with the other hand. A durable guard material over the cargo area's point of entry protects the vehicle and cargo from damage.

Abstract: A synchronous actuator comprises a telescopic cylinder assembly having at least three pivotally connected cylinders, a drive assembly and a driven assembly. The drive assembly is connected to two adjacent cylinders. The driven assembly is connected to three adjacent cylinders. With the drive assembly and the driven assembly, the cylinders of the telescopic cylinder assembly can be extended or retracted synchronously in axial direction.

Abstract: Marine pipe laying systems and methods including a hoisting device for laying an offshore pipeline are disclosed. The hoisting device includes a tower with a tower top side provided with cable pulleys and a moveable traveling block displaceably attached to the tower. The traveling block includes first and second blocks with cable pulleys. A clamp attaches to the first block for holding pipe sections and lowering pipelines after the pipe section connects to the pipeline. The hoisting device includes a hoisting means including hoisting cable and a winch. The hoisting cable can be guided over the cable pulleys on the tower and the traveling block. The first and second blocks are adapted to be releasably coupled for traveling along the tower as a unit and for supporting greater pipeline weights. The second block can be locked to the tower to remain stationary while the first block travels along the tower.

Abstract: A pulley is provided having a first plate and a second plate arranged adjacent to the first plate and connected to the first plate by an axle. An eccentrically mounted sheave is located between the first plate and the second plate and is adapted to freewheel in one direction only. The eccentrically mounted sheave is mounted eccentrically with respect to the axle. A fixed block is mounted between the first plate and the second plate and is adapted to fixedly lock a line between the fixed block and the eccentrically mounted sheave.

Abstract: The line system on a drilling rig is arranged to place the dead line clamp at the upper end of the derrick. A dead line anchor sheave is preferably located to accept wraps of the dead line to insure reduced load on the dead line clamp. The anchor sheave is preferably lockable to prevent rotation and releasable to rotate the anchor sheave for line feeding from a reserve line reel for maintenance operation. A load sensor is optionally provided to sense dead line load for sensing associated hook loads on the traveling block. An motor is provided, as an option, to rotate the anchor sheave for line feeding maintenance operations.

Abstract: A high speed safety block assembly includes a first and second cheek plates with a sheave and axle installed between the cheek plates. The cheek plates each have a recessed area on their inner surfaces and have interlocking ears which increase the safety of the block assembly by preventing the block assembly from coming apart in the event of a screw failure. The sheave of the high speed safety block assembly includes a needle bearing which rolls on the bearing surface of the axle, permitting much higher loads and speeds when the high speed safety block assembly is used.

Abstract: A multi-block rigging system for a heavy crane, pulling or lifting device. The system uses sheave blocks in series orientation to enable the use of standard, economical or preferred, size winch drums and standard, economical or preferred, diameter and length wire rope, each forming a separate set of reeving lines. Each set of reeving lines moves its corresponding load block a proportional distance of the total travel length for the load hook. Alternatively, different line parts of line for each reeved set enables different travel speeds of the load block for different capacity requirements.

Abstract: A high speed safety block assembly includes a first and second cheek plates with a sheave and axle installed between the cheek plates. The cheek plates each have a recessed area on their inner surfaces and have interlocking ears which increase the safety of the block assembly by preventing the block assembly from coming apart in the event of a screw failure. The sheave of the high speed safety block assembly includes a needle bearing which rolls on the bearing surface of the axle, permitting much higher loads and speeds when the high speed safety block assembly is used.

Abstract: An improved block and tackle system comprising a stationary-block housing (10) having attached pulleys (14 & 18) and cam cleat (22), and a moving-block housing (12) with attached pulley (16) and cam cleat (20) Said invention allows a load (8) to be raised, moved, or lowered with a minimal amount of rope (6).

Abstract: A high speed safety block assembly includes a first and second cheek plates with a sheave and axle installed between the cheek plates. The cheek plates each have a recessed area on their inner surfaces and have interlocking ears which increase the safety of the block assembly by preventing the block assembly from coming apart in the event of a screw failure. The sheave of the high speed safety block assembly includes a needle bearing which rolls on the bearing surface of the axle, permitting much higher loads and speeds when the high speed safety block assembly is used.

Abstract: A load-handling device comprising a pair of pulley assemblies each having a body, at least one pulley supported by the body, and having a peripheral outer surface, a rope secured at one end to a support structure and entrained about each of the outer surfaces to interconnect the pulleys in a load-handling arrangement. Each of the pulley assemblies include a one way clutch acting between the body and the pulley to inhibit rotation relative to the body in one direction. The surfaces of the pulleys thereby providing frictional engagement for the rope in the one direction to facilitate handling of the load.

Abstract: A cable and pulley assembly has a first floating pulley unit having a pulley housing and a pair of pulleys rotatably mounted side-by-side in the housing for rotation about a single pulley axis, and a second floating pulley unit having a pulley housing and at least one pulley rotatably mounted in the housing. A first cable is linked to the housing of the first floating pulley unit, and a second cable is linked to the housing of the second floating pulley unit. A third cable extends around one of the side-by-side pulleys in the first pulley unit, around the pulley of the second pulley unit, and around the other side-by-side pulley of the first pulley unit. The resistance on the first cable is then four times that on each section of the third cable, and plural pull points are provided for selective connection to exercise stations.

Abstract: In order to increase the operational safety and to reduce the rope wear, hoisting/lowering apparatus comprise one or a combination of novel features: an adaptor (3) is provided in order to allow the attachment of accessories (50), preferably by insertion. Possible accessories are e.g. holders having a loop for the attachment of hooks, and single or multiple blocks for the formation of lifting blocks. Substantially, the adaptor is formed of a number of slot-shaped recesses which are transversely traversed by rod-shaped retaining elements (11, 9). One of said retaining elements (9) is displaceably mounted in order to allow the attachment resp. detachment of an accessory (50). Another measure is to provide a rope stop (102) on the traction side. The rope (103) runs through the rope stop (102) and drives a knurled wheel (110). At a given rope speed, the wheel is coupled to a pivotable brake appendix (118) by means of a centrifugal coupling (113, 115).

Abstract: A time-based control system (10) for controlling a process incorporating external devices using a predefined response profile (13). The response profile (13) is continuously compared to the actual response of the controlled device (11). A plurality of sensor modules (24) is used to monitor the actual magnitude and direction of change of selected quantities during the process. If the response it outside the user-defined maximum allowable error, appropriate measures are taken to either correct the error, halt the process, or proceed with the process in a time-based mode. The proper response and detection of errors of the controlled device (11) is independent of load, rate, temperature and other external stimuli. The time-based control system (10) can detect errors caused by higher level equipment such as the sensor modules (24). Thus, the time-based control system (10) can detect when any portion of the time-based control system (10) or the controlled device (11) malfunctions.

Abstract: A block and tackle system having two different purchases is operated from a single line. The system includes a primary purchase system and a secondary system having a higher purchase than the primary system. The primary and secondary systems are separated by a one-way block, and the secondary system is connected back to a floating block in the primary system. The secondary system is activated upon initial ease of the line from any given position, with the one-way block locking the line in the ease direction.

Abstract: A cable and pulley system for a multi-station exercise machine involving a tensioned cable led over a series of pulleys, at least one of which is a cradled pulley normally nested in a cradle and radially held in the cradle by the force of the tension on the tensioned cable and radially movable out of the cradle by a greater force applied to the cradled pulley by a second pull cable mechanically connected to the cradled pulley and functioning to move the cradled pulley radially out of its cradle when sufficient tensional force is applied to the second cable to overcome the tension applied to the cradled pulley by the tensioned cable. Additional exercise stations can be added to operate with additional cables and cradled pulleys without changing the manner of operation of other cables and exercise stations.

Abstract: A dual mode crane block is disclosed which crane block includes a sheave mounted therein and a cable retaining member mounted thereon. A hoisting cable can be routed around the sheave to double the lifting capacity of a crane. Otherwise, by way of the cable retaining member, the crane block can be suspended on the ends of a hoisting cable to serve as a weight.

Abstract: A system for tilting and lifting a device includes three pulleys and a cable. A portion of the cable is adjustable. Two of the pulleys are connected to a stationary surface and the third pulley is connected to the object. One end of the cable is connected to the object and the other end provides for the application of force.

Abstract: A manual powered hoist and ramp system for pickup trucks enables a single person to lift heavy objects located on handtrucks or dollies onto the loading platform of the truck. The truck tailgate has a pivoted flap extension to form a ramp inclined from the truck loading platform to the ground when pivoted into its opened ramp position with the flap extended. An accompanying hoist has a counterforce mechanism mounted on a pair of elevated stanchion posts on opposite sides of the truck loading platform for producing an upward assisting lifting force establishing tension in a line extending to the ground for attachment to a handtruck or dolly. That force directed substantially parallel to the ramp tending to move the load up the ramp thus enables a single person to handle a heavier load, such as a refrigerator, for hoisting onto the truck platform.

Abstract: The upper block assembly of a crane is connected to the crane boom via a special universal joint having a pivot axis and a hollow shaft. The cable by which the lower block assembly is suspended is fed through the hollow shaft and extends to the crane winch via a pulley mounted on the boom. Guide pulleys are arranged on the upper block assembly and universal joint respectively so that the cable extending therebetween is coincident with the pivot axis of the hollow shaft. With this arrangement, the lower pulley block has unlimited freedom to swing laterally (side lead angle).

Abstract: Fixed and traveling cable blocks along with first and second cable grip assemblies are supported adjacent the load to be lifted or lowered. A lifting/lowering cable is threaded through the cable grip assemblies before being secured to the load while a separate cable suspends the traveling block from the fixed block. By alternately closing one cable grip and opening the other, the load becomes movable upon the movement of the travelling block. Additionally, by closing the previously opened cable grip and opening the previously closed cable grip, the traveling block may be re-positioned or re-cycled while the load remains stationary. Upon such re-positioning, the lowering/lifting operation of the load can be repeated.

Abstract: A device for raising and lowering a load has a braking device, brake indicator, and a one-way pulley. The braking device uses a wedge-shaped braking element to stop the advancement of a cord. The brake indicator indicates when the braking device is enabled. The one-way pulley allows the load to be lowered at a steady rate and uses a braking element positioned between a stop pin and a braking surface.

Abstract: A deflectable trunnion assembly that has a deflectable eye member or hook. The trunnion assembly is connectable to a pulley block of a hoist. The trunnion assembly has a trunnion block on which a deflectable spherical roller thrust bearing rides. The eye member rides on the spherical roller thrust bearing. The trunnion block is covered by a cover that contains a dome. The eye member ends in a pin that has a balled end. The balled end of the pin rotates within the dome, during deflection within the spherical roller thrust bearing of the trunnion assembly.

Abstract: The present invention relates to a connector assembly for maintaining a crown block with respect to a fall block of a hoist assembly. A tube on each side of the crown block can retain a rod on each side of the fall block. A hydraulic unit on the free end of the tube has a ram that pushes the rod partially out of the tube, when the crown block and fall block are being held together by a hoist cable.

Abstract: An earth drilling machine includes a crown block assembly, a travelling block assembly and a drawworks. The drawworks includes a drum which rotates about a drum axis. The drum axis is oriented at right angles to a fast line plane defined by a fast line sheave included in the crown block assembly. In this way, the fleet angle between the drum and the fast line sheave is kept substantially equal to zero. Various sheave arrangements are described which combine proper selection of sheave pitch diameter, sheave axis angle, and sheave placement to ensure that the fleet angle of all of the sections of line extending between the crown block assembly and the travelling block assembly are reeved with a fleet angle exactly equal to zero. In this way line wear is reduced and the height, weight and windage of the mast are all minimized.

Abstract: Fixed and traveling cable blocks along with first and second cable grip assemblies are supported adjacent the load to be lifted or lowered. A lifting/lowering cable is threaded through the cable grip assemblies before being secured to the load while a separate cable suspends the traveling block from the fixed block. By alternately closing one cable grip and opening the other, the load becomes movable upon the movement of the traveling block. Additionally, by closing the previously opened cable grip and opening the previously closed cable grip, the traveling block may be re-positioned or re-cycled while the load remains stationary. Upon such re-positioning, the lowering/lifting operation of the load can be repeated.

Abstract: The crown block has two parallel clusters of sheaves. In one use the crown block is positioned such that the center of the derrick passes through the axle of one of the clusters and a power cable is threaded through the first cluster of the crown block and the cluster of the travelling block. When one wants to double the mechanical advantage, the crown block unit is shifted so that the center line of the derrick passes midway between the axle of the first cluster and the second cluster of the crown block. For this second use a modified traveling block is used which also has two parallel clusters of sheaves which corresponds to the two parallel cluster of sheaves of the crown block. The power cable is then threaded between the first clusters of the crown block and the traveling block and then through the second sheave cluster of the crown block and the second sheave cluster of the traveling block. The load is connected to a cross member between the two axles of the clusters of the traveling block.

Abstract: The crown block has two parallel clusters of sheaves. In one use the crown block is positioned such that the center of the derrick passes through the axle of one of the clusters and a power cable is threaded through the first cluster of the crown block and the cluster of the traveling block. When one wants to double the mechanical advantage, the crown block unit is shifted so that the center line of the derrick passes midway between the axle of the first cluster and the second cluster of the crown block. For this second use a modified traveling block is used which also has two parallel clusters of sheaves which corresponds to the two parallel cluster of sheaves of the crown block. The power cable is then threaded between the first clusters of the crown block and the traveling block and then through the second sheave cluster of the crown block and the second sheave cluster of the traveling block. The load is connected to a cross member between the two axles of the clusters of the traveling block.

Abstract: A crane block (FIG. 2) is provided for traveling along a central main fall symmetry line (78) defining vertical travel during movement of a hoist within a barge mounted crane. The crown block (50) is mounted to a crane boom (12) and includes a first row of relatively large diameter sheaves (54) in tandem with a second row of relatively small diameter sheaves (58). A movable block (76) is provided between the traveling block (74) and the crown block (50) and includes a third row of relatively small diameter sheaves (60) which are reeved together with the second row of sheaves. A traveling block (74) is provided with a fourth row of relatively large diameter sheaves (56) which are reeved together with the first row of sheaves (54). Sheaves in either the second (58) or third (60) rows are horizontally canted with respect to the main fall symmetry line (78) for vertical travel of the rope which is reeved between the rows.

Abstract: Apparatus for lifting electric line poles is disclosed which also enables a ground rod or stake to be driven into the ground next to such a pole. There is provided a telescopic mast having a hoist with a rope run over pulleys to a lifting hook and attached at the upper end of the mast. For driving in ground rods or stakes a carriage mounted for movement along the mast is used which can be attached to the lifting hook and can secure an air hammer.

Abstract: The invention provides structure consisting of tracks carrying a transporter which moves horizontally on the tracks. A hoist is suspended from the transporter and the hoist includes an elevator for picking up containers at engagement points above the points of suspension of the elevator. Pairs of uprights guide the elevator to maintain stability and the transporter includes guides for alignment with the uprights so that the elevator can move out of the uprights and between the guides for movement horizontally with the transporter with the guides maintaining stability.

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: Interposed between the driving shaft of the tackle and the hoisting hook of the tackle is a flat textile strap or a flat metal braid. The strap or braid is attached to the drum of a drum-pulley keyed on the driving shaft at the end of the strap or braid. The strap passes around the pulleys of a pulley-block comprising an upper block mounted on the frame of the tackle to pivot about a horizontal axis X-X, and a lower block suspended from the strap or braid and carrying the hook.

Abstract: A drilling rig with conventional capacity for working a drilling string is linked to a casing string with a block and tackle which provides sufficient mechanical advantage for the drilling rig to suspend the casing string in the oil well.

Abstract: A hoist for lifting appliances, and more specifically a block-and-pulley arrangement, or a block-and-tackle arrangement. A plurality of pulleys is arranged between two pulley-housing parts. Each of said plurality of pulleys is supported by its own relatively short shaft. Half of the pulley-supporting shafts is supported in the upper pulley-housing part, and the other half of the pulleys is supported by partitions in the lower pulley-housing part. Pairs of partitions in the upper pulley-housing part and pairs of partitions in the lower pulley-housing part are interleaving or out of registry. The load-supporting hook has a shaft which projects vertically through both pulley-housing parts by a bearing, so that it is rotatable relative to the upper pulley-housing part. A load supporting cross-member is arranged in transverse relation to the hook-bearing shaft and the latter projects through its center.

Abstract: Mounted in the upper part of an oil well drilling derrick are horizontal crown beams having end portions projecting beyond the opposite sides of the derrick. A fast line sheave and a dead line sheave are mounted on those beams near the opposite sides of the derrick, and a crown block is mounted on the beams between those sheaves. The sheaves and the crown block are adjustable along the beams. The fast line sheave is movable outwardly into an inactive position on the adjacent projecting end portions of the beams when the crown block is in a position suitable for supporting a fast line directly, and the dead line sheave is movable outwardly into an inactive position on the adjacent projecting portions of the beams when the crown block is in a position suitable for supporting a dead line directly. When both sheaves are in operating positions, the crown block can be placed in any desired location between them.