Abstract: A vehicle for lifting a load with respect to a support surface includes a load carrying member configured to carry the load, a frame, and a support assembly coupling the load carrying member and the frame. The support assembly is configured to move the load carrying member between stowed and deployed positions with respect to the flame. The vehicle further includes a plurality of motion devices that support the frame relative to the support surface, and the motion devices are configured to move the frame along the support surface. In addition, the vehicle includes a control system associated with the motion devices and configured to determine contact forces between the motion devices and the support surface. The control system is further configured to determine stability of the vehicle based on the contact forces.

Abstract: The invention relates to a climbing aid for ladders or the like, comprising an endless traction means running between guide pulleys, from which a person may optionally hang by means of a suspension device, with a drive device (20) comprising a drive motor (21), by means of which one of the guide pulleys may be driven as the drive disc (12) for the drive means (13), with a traction force limitation device and with a device for switching the drive device on/off, which can be actuated by the endless traction means (13).

Abstract: A fire escape apparatus for a building is provided.

Abstract: A stabilized suspended platform comprises a platform suspended from a support unit by a cable. The support unit includes traction means for releasing or pulling part of the cable so as to set the platform at a desired height, and the platform includes propellers for fine movements or stabilizing the platform in space, further including remote control system with means for communicating with the support unit and the platform for controlling the spatial location of the platform. The support means may further include means for moving the platform laterally.

Abstract: Provided are apparatuses, systems, methods, computer readable storage media and other means for performing overhead service of machines. A staging assembly may be used that includes one or more platforms, each having a bottom surface, a floor, and two or more railing support structures. The staging assembly can be suspended, using a suspension system, from one or more support structures disposed on a ceiling. One or more driving means can also be used to drive the staging assembly or other equipment (such as a hoist assembly) along a path that may be defined by a support structure. The driving means can also be automated and/or activated in response to, for example, one or more commands generated by a central control processor. The central control processor, staging assemblies and/or other equipment can all include computer readable media which comprises instructions to perform various tasks, some examples of which are discussed herein.

Abstract: A system for lifting a platform includes a frame attached to the platform. The invention has at least one upright member having equally spaced holes longitudinally aligned, with each of the holes having an upper surface and a lower surface. A motor is attached to the frame, and a pinion is driven by the motor. The frame carries the motor and pinion. The pinion has a plurality of equally spaced teeth that radially extend from the pinion. Each tooth has a roller that is freely rotatable about its axis. The rollers roll over the lower surface of the holes when the motor rotates the pinion in a direction to raise or lower the frame and platform. A safety dog is attached to the frame to prevent the platform from falling if a motor were to fail.

Abstract: A device for enabling access to a structure above ground or sea level, in particular a rotor blade of a wind turbine, by lowering and/or lifting the device in relation to the structure, the device including a frame structure,—means for supporting the device in relation to the structure, and—means for lowering and/or lifting the device in relation to the structure, where at least part of the frame structure includes a track portion, the track portion being adapted to guide an, in relation to the track portion, movable object along the track portion, where the means for supporting the device in relation to the structure are configured for positioning the device in relation to the structure, and the means for supporting the device in relation to the structure are configured for facilitating a movement of the device essentially in the longitudinal direction of the structure.

Abstract: A stair climbing aid comprises two slide rails, an assist member, a control mechanism and two positioning assemblies. The slide rails and the assist member are assembled to handrails at both sides of the stairs. The control mechanism is disposed on the assist member to be controlled by the user. The positioning assemblies are disposed at both sides of the assist member, each positioning assembly is provided with an engaging portion to be engaged in the respective positioning portions of the slide rail. Thereby, an anti-slide effect is produced, so as to prevent the user from falling down the stairs and to help the user move from step to step safely.

Abstract: An elevator car includes a cross-head portion and a balustrade mounted to the cross-head portion. The balustrade is moveable from a retracted position for normal operation of the car to a deployed position for inspection operation of the car. The car further includes a second retractable safety device also mounted to the cross-head for preventing or limiting movement of the car. The balustrade includes at least one control for operating the elevator car during the inspection operation, the control being arranged so that the control cannot be operated when the balustrade is in the retracted position.

Abstract: An aerial work apparatus having a boom mounted to a base, a platform attached to the distal end of the boom, a boom mechanism for positioning the platform, a boom control module mounted with respect to the platform, a vertical load-sensing mechanism mounted at the platform for measuring the platform load and generating a load signal based on that measurement and a controller operationally attached to the boom mechanism and boom control module. The controller receives the load signal and at least one position signal relating to the position of the platform and generates at least one control signal based thereon. The boom mechanism is controlled by the boom control module through the controller. Preferably, the load-sensing mechanism is held in position by a vertical holding column attached at the distal end of the boom so that the mechanism fully supports a platform support member attached to the platform.

Abstract: A fire engine having an extension ladder mounted thereto, wherein said extension ladder may be rotated through a full 360 degrees while the ladder is fully extended—regardless of the vertical angle or position of the ladder with respect to the longitudinal axis of the fire engine. The ladder is mounted to the fire engine between a forward portion and a rearward portion. The fire engine employs at least two sets of vertically offset and laterally extendable stabilizers, that are adapted to communicate with the ground and stabilize the fire engine while the ladder is in use. The stabilizers are mounted substantially beneath the mounting point of the ladder and are designed to reside within the width of the fire engine body when retracted. Each set of stabilizers is arranged to diverge in the direction of extension in order to provide maximum stabilization to the fire engine.

Abstract: An aerial work platform supported by a riser boom, a telescoping main boom, and a jib boom. Boom movement may be controlled by a platform control module or a ground control module connected to a controller by a controller area network (CAN). Movement of the platform and the jib boom are limited to a predefined envelope. If an operator attempts to move the platform outside the envelope, the controller automatically retracts the telescoping boom section or automatically levels the jib boom section in order to maintain the platform within the acceptable envelope. Boom section select switches permit the operator to select and move sequentially or simultaneously in different directions. Timers which are part of the system include various interlocks to accomplish safety and power saver features.

Abstract: A guide rail system is used to erect towers, to place equipment on towers and for maintenance of towers. The guide rail may be added to existing towers, a climbing lifting platform is attached to the guide rails and is used to transport items up and down the tower. The platform may also be used to carry up tower sections during erection of the tower.

Abstract: While a crawler body 110 is traveling, infrared sensors 144 and an elevational difference calculator 132 incorporated in a controller 130 detects the magnitude of a step present ahead of the crawler body 110. A safety speed calculator 134 calculates a safety speed based on the magnitude of the step detected and on the position of the platform 116 relative to the crawler body 110, which position is detected by various detectors 141˜143 and by a position calculator 133. A comparator 135 compares this safety speed with the traveling speed of the crawler body 110, and if the current speed of the crawler body 110 is greater than the safety speed, then the comparator 135 outputs a warning signal. Upon receiving this signal, a restrictor 136 controls a valve controller 131 to reduce the speed of the crawler body 110 such that the crawler body 110 can travel over the step safely.

Abstract: The invention consists of an active scaffolding system adapted to hold a payload, said active scaffolding system comprising: (a) a plurality of adjustable links and rigid links connected by joints; (b) a plurality of actuator devices associated with the adjustable links so as to change to length of the adjustable links; (c) a microprocessor to determine how the lengths of each of the adjustable links throughout a number of time steps; the microprocessor being provided with computer program instructions to resolve the Cartesian end point translational and rotational motions; and (d) the adjustable links, rigid links, and actuator devices forming an active scaffolding adapted to move a payload around environmental obstacles while supporting said payload against the force of gravity.

Abstract: A powered lift platform apparatus is disclosed having a fixed support structure and two independently operable platforms which move in both the vertical and horizontal direction, for use with transport containers, such as trailers, shipping containers or rail cars. Each platform comprises an extended work surface or walkway and two moveable end platforms which extend perpendicularly to the extended work surface. Each platform may be independently raised and lowered, and each may be moved laterally toward the opposite platform. The distance between the two platforms and the length of the end platforms, coupled with the range of lateral movement of each platform, are such that the free ends of opposing end platforms can be juxtapositioned to create a rectangular pathway for workers to completely circle the transport container.

Abstract: An automatic foldable emergency ladder system for use in a building having a smoke detecting device includes an inverted L-shaped housing having a horizontal portion and a vertical portion and being securely mounted to a perimeter wall of a roof of the building; a control unit mounted in the horizontal portion of the housing and having at least one input port for receiving a signal from the smoke detecting device; an electrically powered driving device mounted in the horizontal portion of the housing and electrically connected to the control unit for receiving a signal therefrom and being activated/deactivated therefor; a spool unit rotatably mounted in the housing and driven by the driving device; a foldable ladder securely coupled to the vertical portion of the housing at one end thereof and having at least one wire which is secured to the spool means at one end thereof and an opposite end thereof is coupled to a free end of the foldable ladder such that the ladder can be folded/extended by the spool unit;

Abstract: A lift has a base frame supported on a pair of screw jacks and a pair of support legs when a multi-stage mast on the lift is to be raised. The support legs are slide mounted in guides and each is downwardly biased away from a control switch on the base frame so that the switch is open unless the leg is loaded by the weight of the lift. A transport carriage is mounted to roll on sloped tracks on the base frame and is connected to the base frame by a hydraulic cylinder unit which functions when activated to pull the carriage downwardly into ground engagement to take the load of the lift from the jacks and support legs. A control circuit prevents the mast from being raised while the lift is supported on the carriage.

Abstract: A platform at one side of a battery of rolls in a calender can be moved up or down when the rolls are not driven or when a breastwork at the parapet of the platform is moved to a raised position so that an operator standing on the bottom wall of the platform cannot reach a nip of the rolls while the rolls are driven.

Abstract: A lifting apparatus has a movable chassis, a vertically movable platform disposed over the chassis and a vertically swingable, telescopic boom body connected between the chassis and the platform. The chassis, boom body and platform are arranged to form a Z-shape in side view. A detecting mechanism for monitoring the movement of the platform includes a winding drum, and a detection wire wound on the winding drum and having an end fixed to the platform. The boom body is extended at a rate correlated to the angle of inclination of the boom body so that the platform remains horizontal while moving vertically relative to the chassis.

Abstract: The present invention provides personnel lift devices that include at least one of six design features. Each of the design features is discussed individually. The lift device includes an operator's cage assembly exhibiting ease of operator access and a safety enhancing interlocked design. A control mechanism, requiring the use of both hands to maneuver the controlled device, further enhances the safety of apparatus of the present invention. Interlocked outriggers provide enhanced structural stability and safety. A telescoping mast of extruded metal design includes a plurality of tee slots and/or sliding engagement during extension and retraction of the individual mast stages. A transfer mechanism releasably positionable at a plurality of heights and includes a bumper/roller assembly that is either fixed or freely movable, depending upon the portion of the device being transferred that is bearing the weight thereof.

Abstract: An automatic leveling system for a four-wheel vehicle system having outrigger assemblies at each of the four corners of the vehicle chassis and in which each outrigger assembly has an outrigger pad and a hydraulic cylinder for moving the pad downwardly and upwardly relative to the ground. The leveling system includes a low-pressure high-flow source of hydraulic fluid which is connected for one-way flow into the head ends of all four of the cylinders to lower all pads to the ground and then maintain them in contact with the ground. A level sensor senses the relative levelness of the right front and left rear corners of the vehicle and high-pressure low-flow hydraulic fluid is connected to the head end of the cylinder at the lower of those two corners to raise that corner of the vehicle relative to the ground.

Abstract: A fire/rescue system which overcomes the deficiencies of internal and external fire escapes noted above by providing a plurality of compartments which are mounted to traverse the vertical side walls of a high-rise building to carry individuals from designated locations, vertically distributed along the side walls of the building, to safety of the base of the building. The compartments are stored prior to use and between uses on the roof of the high-rise building, preferably within a specially-designed garage therefor, thus overcoming the aesthetic deficiencies of external fire escapes. In the event a fire and/or smoke sensing device is activated within the building, one or more of the compartments is ejected from the rooftop storage facility and tranverses down the exterior wall(s) of the building.

Abstract: A retractable ladder apparatus (30) for access between a lower and an upper floor is provided. A ladder (60) is moved by moving means, which may be a garage door opener (40), between a position of storage within the upper floor to a position where the lower end of the ladder abuts the lower floor.

Abstract: An emergency escape system for multistory buildings in which stair units are stored in recesses in the floor of each above grade level of the building. The stair units are released for gravity depolyment to the next below balcony in an emergency, and a cover panel is opened to enable egress by building occupants through the recess, down the deployed stairs to the next balcony and so on until ground level is reached.

Abstract: The invention relates to a balanced supporting arm, comprising a substantially elongate structural member which is mounted on a supporting assembly for tilting movement and which is provided with at least one bellows mounted under at least one end of the supporting arm. According to the invention, the bellows has an inoperative condition wherein it is at least substantially empty and an operative condition wherein it is filled with a gas under a predetermined working pressure. The balanced supporting arm comprises means for detecting the tilting speed of the supporting arm and, further, means, connected with the means for detecting the tilting speed, for bringing the bellows from the inoperative condition into the operative condition when the means for detecting the tilting speed detect that the tilting speed exceeds a predetermined value.

Abstract: This invention relates to a device for automatically securing a climber climbing a wall, wherein it comprises:a shaft guided in rotation,at least one drum comprising a groove for receiving a line wound around the drum at least once,an irreversible control member interposed between each drum and the shaft preventing a relative rotation between the drum and the shaft in a first direction and allowing rotation of the drum in a direction opposite the first direction,a system for continuously taking-up the slack of the line,and a means for controlling rotation of the shaft in a direction opposite that allowed by the irreversible control member, enabling the climber, who has fallen, to descend.

Abstract: An electrical deactivation circuit and a two piece overhead guard assembly including two separately movable bar members which extends upward and over the head of an operator located on the upper work platform of an aerial work platform. The guard bar members are connected to the frame of the upper work platform by a pair of movable support assemblies, the movement of which actuates impact detection induction type proximity switch means to interrupt electrical power applied to the electrical control circuits and stop the engine powering the aerial work platform. Each movable support assembly includes a pair of spring loaded mechanical subassemblies including a pair of clamp members between which is located an elongated coil spring whose stiffness is varied in accordance with the distance separation of the clamps. An inductive type proximity switch is located in the lower end portion of each spring to sense movement of the inner end of a respective guard bar member.

Abstract: A fire escape system is described in which a latched escape door in a building is unlatched by withdrawal of a restraining pin from a latch mechanism, producing automatic opening of the door by any of various door-opening self actuating means described. In one embodiment, withdrawal of the restraining means results as a consequence of the transmission of a signal generated by a fire detection device, to an electric windlass system, which thereupon retractably winds a cable attached to the pin, withdrawing it from the latch mechanism.

Abstract: This invention relates to the automatic control of work platforms and in particular to a circuit means that provides a safe operation and automatic relevelling of a work platform that is being raised and lowered by electrically powered hoists. Angle sense means are used to detect out of level orientations of the platform either along the longitudinal or transverse axis of the platform. When the angle sense means signals are interpreted by the circuit means appropriate hoist control signals stop the travel of the platform for a pre-determined period, control the hoists to bring the lowest portion of the platform up into a substantially level position, stop the travel of the platform for a pre-determined period and recommence the direction of travel of the platform.

Abstract: A security unit for a hanging stage scaffolding motorized by two electric winches of which each is supplied through a control circuit, said stage having a platform or gondola directly or indirectly suspended by two lugs pivotally mounted on each of said winches, respectively, characterized in that each lug carries a pin adapted to penetrate a slit in a slide to move towards the left or right said slide according to the default of the gondola to the horizontal, the displacement of said slide being adapted to bring it in contact with the opening thereof.

Abstract: An automatic escape ladder is set forth for use particularly in multiple unit, multi-level residential dwellings. A compact interfolded ladder is positionable within an associated enclosure wherein said enclosure includes an upper pivotal portion and a lower portion secured to an extendable ladder. Upon activation through a fire alarm system, a solenoid latch mechanism will release said ladder and said bottom plate enabling said ladder to extend and lock.

Abstract: The present invention provides a valve for controlling fluid flow. The tapered actuation surface of the actuation cam of the present invention controlled by electric motors may be utilized to gradually open and close the various pistons which regulate flow through the valve passageways. An actuation monitor acts to measure the amount of piston actuation so as to permit interactive control of the valve. One embodiment of the present invention may be utilized in response to signals received from an apparatus connected to a boom support member mounted on the back of the truck wherein it is desired to maintain the boom support apparatus in the substantially vertical direction.

Abstract: A crane with an anti-skewing device comprising a platform suspended under a bridge deck by two end truck assemblies supported by runways on a bridge. Each end truck assembly includes two sets of trolleys and an upper load bar interconnects the two sets of trolleys. A lower load bar is suspended from the upper load bar by a kingpin for rotation about a vertical axis. Hinge tubes support the platform on the suspension assembly for pivotal movement in a direction lengthwise of the platform. Each end truck assembly is driven by a variable speed motor. As skewing occurs a mechanical sensing mechanism senses relative movement between lower load bar and the upper load bar and provides a signal to an electronic circuit causing one or both of the motors associated with the end truck assembly on which the sensing mechanism is mounted to increase or decrease the speed of the motor and thereby correct the skew.

Abstract: An improved work platform suitable for mounting on a vehicle mounted telescoping boom. The work platform includes a fixed platform section mounted on the tip of the boom in conjunction with a leveling mechanism. Two movable side platform sections are pivotally fastened at one of their ends to the fixed platform section for independent movement on either side of a centerline. The side platform sections may be moved apart in a scissors-like motion so that the platform may be maneuvered to straddle the object being worked on. Bumpers and troughs are provided along the inner edge of the side platform sections to protect the object being worked on and to prevent articles from rolling off the platform. When the side panel sections are moved into abutment to use the platform as a conventional unitary platform, a hinged flap on one of the side platform sections covers the abutting edges of the side platform sections, the bumpers and the troughs.

Abstract: Access equipment including a vehicle (10) on which stands a mast (14) movable between horizontal and vertical positions and mounted for rotation about an axis (13). The mast is telescopically extendible and carries a pivoted boom (17) which is also telescopically extendible and carries a further boom (19) with a working platform (20) thereon. Booms (17, 19) can operate only when the mast (14) is vertical. A cable system maintains platform (20) level for all positions of booms (17, 19) and at least two sets of conduits extend from the vehicle (10) to the platform (20). A take-up system for maintaining the conduits taut is located in casing (54) attached to mast (14) and includes sets of rollers (61 to 69) for supporting the conduits around curved paths and preventing them from becoming entangled.

Abstract: A pivotable safety railing for a platform such as a helicopter landing pad is disclosed. The safety railing includes a suitable hand railing of sufficient height to protect a person on the landing pad, and mounted on a pivot shaft extending along an edge of the platform. The pivot shaft allows the railing to pivot downwardly to a horizontal position while a helicopter is landing or taking off, and to pivot upwardly to an upright, or vertical, position, when a helicopter is resting on the landing pad. The pivot shaft is driven by a suitable electric motor which is controlled by sensors located on the landing pad, the sensors causing the pivot shaft to be driven in a direction to move the railing to its horizontal position whenever there is no helicopter present on the pad, and causing the shaft to be driven in a direction to raise the railing to its vertical position whenever a helicopter has landed.

Abstract: Apparatus for use in supporting a plurality of override control handles of a control valve assembly, the control handles supported for movement in a first direction between engagement and disengagement with the control valve spools and supported for movement in a second direction to cause controlled movement of the valve spools. The apparatus includes a plate having slots housing the control handles and the plate being supported for slideable movement such that movement of one control handle between a valve spool engaging position and a disengaged position causes movement of the other control handles between an engaged position and a disengaged position.

Abstract: Access equipment of the type comprising a turntable on a mobile base and having a lower boom, at least one upper boom and a platform carried by the upper or uppermost boom has the operation of the lower and upper booms interlocked so that the lower boom must be locked in an elevated position before the upper boom or booms can be elevated, and at least one upper boom is extensible.

Abstract: There is provided an over-translation sensing and centering apparatus for a scissors lift work platform comprising a linear cam arranged with electronic sensing means to detect an out-of-balance condition. For transmitting the relative angular position of the scissors members to linear movement of the cam, there is provided a control member pivotally mounted to the cam having bar links pivotally mounted to each extremity and connecting the control member to each scissors member. As each scissors member extends, the angle of the members with respect to the base of the vehicle causes the respective extremity of the control member to shift. As long as the scissors members move in equal opposing increments, the control member mounted on the linear cam rotates only, but if one member moves more than its counterpart, the control member is caused to shift and thereby move the linear cam.

Abstract: A revolving block having an inclination correcting mechanism housed therein is adapted to revolvably support a working implement, such as a ladder or boom, mounted on a high place working vehicle.

Abstract: An automatic leveling device for crane boom supported work baskets includes a weighted and damped plumb sensor coupled to a first potentiometer and a second potentiometer for measuring the relative angle between the crane boom and the basket pivotally attached thereto. The measured output levels of the two potentiometers are applied to a servo circuit that controls a linear power actuator pivotally attached between the boom and basket to thereby maintain the basket vertical. The basket may be electrically isolated from ground for use on "live" wire maintenance when the basket carries a storage battery for powering the servo and actuator and if the basket controls for boom movement are transmitted to the crane through a fiber optic or radio remote control link.

Abstract: An improved system for monitoring lift chains included within mast assemblies in material handling vehicles disables downward movement of the forks upon detection of a first level of slackness in a lift chain. Since upward movement of the forks is not disabled, the forks may be raised to clear any obstruction causing the chain slackness. A lift chain may also be monitored to detect a broken chain in which case all vertical movement of the forks is disabled. In a material handling vehicle wherein the operator is elevated along a first mast and the forks are elevated along a second mast connected to an operator's platform, dual lift chains in the first mast are individually monitored for both slackness and breakage while dual lift chains in the second mast are monitored in common primarily to detect slackness. Lateral and rotational movement of the forks is also disabled for detection of a slack or broken first mast lift chain, but not for detection of a slack or broken second mast lift chain.

Abstract: A road towable platform having a sectional mast for rapid erection at the face of a structure for the performance of work thereon. The platform is vertically driven on the mast by means of dual independent drives each comprising a motor, a centrifugal overspeed brake, a triple reduction spur gear train, and a pinion engaging an independent rack on the mast. Each motor also has an integral disc brake engaged when the power is off.

Abstract: A safety device for securing a scaffold to the side of a building in order to prevent movement thereof is disclosed. Such securing of the scaffold is achieved by placing a lanyard around the rope supporting the scaffold and securing the lanyard to a stud on the side of a building through the use of a yoke.

Abstract: A work platform for buildings having a guard rail having, at one end, a movable part pivotally mounted for movement about a horizontal axis between a working position and an upright safety position the guard rail including a mechanism carrying switch means arranged in the working position of the said movable part to be positioned to contact a member on an adjacent platform to control a circuit to stop the platform moving in a vertical direction and the movable part being controlled by said mechanism which also positions said switch means to prevent the platform passing one another when the end frame movable part is in any position except the safety position.

Abstract: A tension sensing device for scaffolds suspended by at least one hoist cable is described. The tension sensing device generally comprises a support structure adapted to be secured to the scaffold and having guide means for directing the hoist cable through the device, lever arm means for sensing the tension on the hoist cable, and switch means for detecting a slack cable or a strained cable condition. The support structure includes a cover plate assembly with at least one section of the cover plate assembly constructed from a transparent material so that the tension on the hoist cable may also be visually observed.

Abstract: An electronic control system allows control over the safe operation of an aerial work platform machine. The control system uses a firmware programmed digital processor to execute a sequence of steps to monitor and control the safe operation of the work platform machine so that tipping and damage are prevented. The control system has sensors to measure the condition of the work platform machine and has outputs allowing control over the work platform machine.

Abstract: The free end portion of the boom of a crane carries a separable pivot bearing defining a horizontal pivot axis for a second bearing which reciprocably guides an upright column for one or more galleries. When the cable which is used to lift or hold the column breaks and the column begins to rapidly descend, such movement of the column activates a composite brake mounted on a frame surrounding the column at a level above the second bearing. The brake holds the column against downward movement with reference to the frame whereby the frame tends to descend toward the second bearing against the opposition of several shock absorbers which reduce the likelihood of damage to and/or excessive swaying of the boom and/or injury to the occupant or occupants of the gallery. The speed of downward movement of the column is monitored by a detector which activates the brake as soon as the speed exceeds a preselected value.

Abstract: A system is disclosed for safely transferring personnel to and from a sea launch from and to a tanker, a freighter, a bulk carrier, passenger ship or any other vessel or platform relatively larger than the launch or a boat. The system comprises a carrier, which is lifted and lowered by a winch including a hoisting motor, a continuously running tensioning motor, at least one cable connected to said carrier and operatively connected to the tensioning motor and the hoisting motor, and a coupling device disposed between the hoisting motor and the tensioning motor. A weight, which is part of the carrier, or which is suspended underneath, or, alternately, a line attached to the launch and carrier, provides the necessary compensation to the changing personnel weight and allows the carrier to follow motion of the moving deck of the launch.