Abstract: A winch comprising one or more of an overwinding prevention unit, a load spin prevention device, a power supply board comprising substantially circular electrical contacts, a rope tension control unit, and a system comprising the winch and a load, attached to the winch, having a load battery chargeable via the winch.

Abstract: The disclosure relates to hoisting accessories for wind turbines. The hoisting accessory is configured to be rotatably attached to the rotor hub and is further configured to assume a hoisting configuration and a passive configuration, wherein in the hoisting configuration, a wind turbine blade can be hoisted and mounted substantially vertically to the rotor hub, and wherein in the passive configuration, the rotor hub carrying one or more wind turbine blades can be rotated. The present disclosure also relates to kits including such hoisting accessories and methods of hoisting wind turbine blades.

Abstract: A windlass system and method in which an inertial force resulting from an abrupt removal of primary operating power from a primary source of power during a lifting operation being carried out by a windlass of the windlass system is attenuated to reduce load forces generated by the inertial force.

Abstract: A tether line is mounted in a retriever and, when a water vessel is launched into the water, the retriever applies a tension force to the tether line. After the water vessel is launched, the tension on the tether line pulls the water vessel from its launched floating position towards the stationary object. The retriever is rotatably mounted on the water vessel or the stationary object such that it will pivot around a vertical axis and point in a direction towards and along the tether line. A spool mounted on the structural unit holds the tether line, and an electrical or mechanical motor, such as a spring B-motor, places a torque on the spool and a tension on the tether line. After the water vessel is launched, the tension force from the motor pulls the water vessel from a launched position to the stationary object.

Abstract: A windlass system and method in which an inertial force resulting from an abrupt removal of primary operating power from a primary source of power during a lifting operation being carried out by a windlass of the windlass system is attenuated to reduce load forces generated by the inertial force.

Abstract: An infeed system is provided for a chipper or grinder having a processing portion wherein an item is processed into smaller pieces. The infeed system is upstream of the processing portion and includes a feed roller, a first hydraulic motor in communication with the feed roller for selectively actuating the feed roller, a second hydraulic motor in communication with the feed roller for selectively actuating the feed roller, and a hydraulic pump for providing hydraulic fluid to the first and second motors. A directional control valve and a relational control valve are between the pump and the motors. The directional control valve allows the hydraulic fluid to operate the first and second motors in a forward direction and in a reverse direction, and the relational control valve allows the hydraulic fluid to operate the first and second motors in series and in parallel.

Abstract: A tension detector may detect and help correct tension in a lift cable. The cable may include a lift cable within a telescopic structure, such as a telescopic tower. The tension sensor may detect when the cable tension is outside a high tension threshold and a low tension threshold and trigger an alert when outside the thresholds. The alert may be an audible alert or a visual alert. A controller may prevent a user from making the tension worse and encourage an operator to correct the tension problem by preventing a winch from expanding or retracting the telescopic structure. The tension sensor may use springs to calibrate the thresholds for the high tension and low tension and a series of pulleys to manipulate an arm to engage a tension sensor.

Abstract: A load sensing transmission device in which when a rotation is transmitted to a sun gear, and planetary gears are rotated, if the rotation of an internally-toothed ring gear disposed at an outer circumference of the planetary gears is restricted in at least one direction, a decelerated rotation is output from a planetary carrier by revolution of the planetary gears. When the internally-toothed ring gear is rotated without being restricted, and simultaneously rotated together with the revolution of the planetary gears the rotation which is not decelerated is output from the planetary carrier. Existence and non-existence of the restriction of the rotation of the internally-toothed ring gear are switched by sensing a load by the load sensing mechanism and performing the engagement and disengagement by an engagement pawl. The rotation of the planetary carrier is output through a plate with slider, load springs, and a plate with cam.

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 control system is provided for one or more chain drives. The control system includes a automation control system or control device in communication with a control board installed on one or more chain drives. The control board can include a microprocessor and a memory device. The memory device stores one or more computer programs or algorithms executable by the microprocessor to generate a plurality of commands to control the operation of a component, e.g., a motor, of the chain drive in response to receiving an operational command from the automation control system or control device.

Abstract: The invention relates to a subsea marine load raising and lowering system (1) for use on a vessel, preferably a vessel for laying an offshore pipeline, which system comprises first and second winches (2, 6) for raising or lowering first and second cable portions (4, 8) connected via an equalizing sheave (11), to the axle (12) of which a load connector (13) is connected. The system comprises operating means to perform synchronous raising or lowering of the cable portions. The system further comprises overload protection systems provided at both winches, and a safety assembly (15) preventing any substantial further movement of the cable portions (4, 8) in case the cable portions do not operate synchronously, comprising a structure (15a) mounted to the axle (12) of the equalizing sheave (11) having passages (15c) for the cable portions and further comprising stops (15b) arranged on each cable portion above and in the vicinity of the structure (15a).

Abstract: A system for raising and lowering equipment and including a fixed support arm for attachment to an elevated support structure, a movable carriage for carrying the equipment, a cable extending between the fixed support arm and the movable carriage, and a winch for spooling and unspooling the cable to raise and lower the movable carriage relative to the fixed support arm. A locking mechanism secures the carriage in its raised position, and alignment guides position the carriage to make electrical connections as the carriage is engaged onto the support arm.

Abstract: A system for controlling slack in a winch rope associated with a vehicle can include a winch, a plow, and a support member pivotably coupled to the plow and carrying a pulley that receives the rope for raising and lowering the plow. A limit switch can be operatively associated with the winch and configured to selectively enable and disable lowering of the plow by the winch. A first member can be carried by the support member and operatively associated with the switch. A biasing member can bias the support member to a first position when a load on the winch rope is below a predetermined threshold. The first member can be in at least substantial alignment with the switch when in the first position. The switch can change an activation state upon the first member being in the first position to automatically disable lowering of the plow by the winch.

Abstract: A drilling rig control system adapted for easy interface between a compressed air supply and a drilling rig clutch and brake. Both manual and automatic controls are provided to initiate the device to interrupt and vent the compressed air supply to the clutch and concurrently communicate compressed air to the brake to cause it to engage the drum winding the cable for the rig. Over-pull sensors monitor cable tension and initiate valves in the control system to initiate the compressed air interruption and rerouting upon any sense of over-pull.

Abstract: The invention relates to a hoisting device for use at a wind turbine, in particular for use in a wind turbine nacelle, which hoisting device 1 comprises a reel 4, a drive motor 12, control means 14 and a hoisting line 6. The hoisting line is a rope, which comprises synthetic fiber material, e.g. a high-tech rope. Hereby it is achieved that the hoisting device can be provided in a compact form, compared with traditionally used hoisting means, since the synthetic rope used as a hoisting line is characterized in having a high tensile strength and a low weight, whereby a rope having a comparable low weight can be used for lifting the same load, for which traditionally a steel wire having a relatively large weight has been used. Further, since the weight of the rope itself is relatively small, a drive motor, gear etc. having reduced capacity, power etc., can be used as compared to a traditional hoist, thereby also aiding in reducing the size, weight, complexity, cost etc. of the hoisting device.

Abstract: A method for controlling the tension in a spooled device disposed on a winch, comprises providing an input signal to a controller indicative of a measured tension in the spooled device, providing an input signal to the controller indicative of a desired tension in the spooled device, and providing an output signal from the controller to adjust the speed of the winch based on a difference between the desired tension in the spooled device and the measured tension in the spooled device.

Abstract: An elevator hoist apparatus includes a stationary frame member, a main shaft, a stationary element disposed to said stationary frame member, a rotary frame member supported on said main shaft and extending in a radial direction in axial opposition to said stationary frame member, a rotary element disposed to said rotary frame member in opposition to said stationary member, a brake unit including a brake portion extending through an opening in said stationary frame member, and a rope sheave disposed to said rotary frame member for rotation therewith. The brake unit includes a brake portion disposed in a hollow portion of the stationary frame member of the stationary member and extending through the opening portion and disposed to the inner circumference of the stationary frame member or the rotary frame member. The magnetic path for the brake unit extends through one portion of the rotary frame member or the stationary frame member. Small-size and high performance are realized.

Abstract: A hoist system for handling a 400 Hz cable used for aircraft electrical servicing, that utilizes electrical circuitry where wire rope position sensing is accomplished using a grounding circuitry. The system employs an AC drive that relies on circuit completion through “sinking logic.” Electrically connected are wire rope guide rollers, a control pendant, a bridge horizontal control relay, which is in electrical communication with a horizontal bridge lock-out bar. The wire rope is used as an electrical conductor for control voltage only. A lower limit contact bar extends above a plane between the wire rope guide rollers and the take-up spool, as serves to prevent the wire rope from rewinding in a reverse manner on the take-up spool. A horizontal bridge lock-out bar extends above a plane between the wire rope guide rollers and the take-up spool and is used to allow or inhibit horizontal bridge movement.

Abstract: An improved hoist for raising and lowering a weighted object secured to a hoist cable, wherein the improvement comprises a safety switch in series with an up-down switch of the hoist. The safety switch has an actuating member with spaced-apart first and second portions on either side of the hoist cable and proximate the take-up shaft of the winch, and, when the hoist cable becomes unweighted or becomes wound upon the take-up shaft in an improper direction, the hoist cable moves the actuating member and prevents the up-down switch from applying power to the winch motor, thereby disabling the winch motor.

Abstract: A lifting device utilizing a utility winch having an electric motor and cable drum. The cable on the cable drum extends around a pulley located on a load cell beam. Excessive loads will deflect the load cell beam causing a contact on a micro switch to be engaged to shut off power to the motor. The cable is attached to a trolley which reciprocates along a mast between upper and lower limits. The trolley includes a brake which has a drum which engages the mast to stop in travel of the trolley in the event of a cable breakage. Cable tension is also sensed and cable slack will actuate a switch to interrupt power to the electric motor. Various load handling attachments are detachably securable to the trolley.

Abstract: In order to increase winch safety, power and utility method for using a winch and a method for mounting a winch based on ensuring that the force exerted by the winch cable on the drum rotation axis and the drum rotation axis remains perpendicular throughout winch operation are disclosed. An improved winch mount which allows the user of the winch to ensure that the force exerted by the winch cable on the drum rotation axis and the drum rotation axis remains perpendicular throughout winch operation is disclosed.

Abstract: An apparatus for the assisted handling of a load includes at least one motor unit, which actuates the winding and unwinding of a flexible traction element; one or more guiding sheaves; and a detector for detecting the weight of the load and the force applied thereto, arranged at an element for supporting the guiding sheave that is arranged directly downstream of the pulley or drum actuated by the motor unit.

Abstract: A support for a garbage chute cleaning apparatus includes a cart having ground engaging wheels. Outrigger legs are provided for anchoring and providing lateral stability to the cart. A rotatably mounted reel is provided having a length of line mounted on the cart. Two telescopically extendible vertical support columns are mounted on the cart. A telescopically extendible horizontal cross-beam extends between the two vertical support columns. The horizontal cross-beam has a remote end with a line guide which receives line from the rotatably mounted reel. A Counterweight is mounted to the cart opposite the remote end of the horizontal cross-beam. This provides a counterbalance to a garbage chute cleaning apparatus supported from the line at the remote end of the horizontal cross-beam.

Abstract: The present invention provides a drilling system for drilling a borehole. A motor continuously coupled to the drawworks may be utilized to raise and lower a drill stem to continuously control the weight on bit at a desired value. A second motor rotates the drill stem. A control circuit is coupled to both the motors and receives information from various sensors which includes information about the rate of penetration, weight on bit; hook load, and rotational speed of the drill bit. The control circuit controls the drawworks motor to control the drill stem motion in both directions. In one mode the a desired rate of penetration is maintained by controlling the weight on bit. In another mode, the control circuit causes the drilling to start at an initial rate of penetration and then it starts to vary the rate of penetration according to programmed instructions to optimize the drilling efficiency.

Abstract: A load lifting apparatus comprising: a frame; a load engaging mechanism for engaging a load having a weight; a hoist mechanism for raising the load engaging mechanism, the hoist mechanism being mounted on the frame and including a member supporting the load engaging mechanism during lifting of the load, the member having therein an aperture; a sensor disposed in the aperture for detecting a force exerted by the load engaging mechanism on the member, the sensor providing a variable output indicative of the magnitude of the force; and a control for disabling the hoist mechanism when the output reaches a first predetermined value corresponding to the maximum load of the load lifting apparatus.

Abstract: A primary device placed at the upstream end of a duct and a relay device placed at an access point pull a cable through respective duct segments. The pulling speed of the primary device is controlled by an operator. The pulling speed of the relay device is variable in response to movement of the cable by the primary device to maintain equilibrium between the pulling speeds of the devices. The pulling tension exerted upon the cable by each device is monitored and discontinued upon reaching a predetermined maximum value. At the inlet to the second segment, lubricant is supplied to the cable at a quantitative rate which is proportional to the pulling speed.

Abstract: An elevating system especially designed for raising and lowering battens used in stages. The elevating system preferably uses two or more winch assemblies with synchronous motors coupled together in parallel to an AC inverter to provide smooth, ramped starting and stopping of the winch assemblies as well as torque boost, speed boost, and electric braking. Each winch assembly is provided with numerous safety features such as overload and underload protection, automatic releveling of the batten, thermal overload protection and cable drum lock protection.

Abstract: A compensating device equipped with a hydraulic cylinder/piston arrangement as a damping member, and a sheave operatively connected with the cylinder and piston arrangement, and a hydraulic accumulator connected to the cylinder, for use on board a trawler vessel operating in autotrawl mode for dampening shock forces or alternating stresses on trawl pulling wire elements between the trawler vessel winch system and a bottom trawl.

Abstract: A lifting appliance, especially for a patient lifting device, comprises a telescopic column (10) having a carriage (22) which is reciprocable in the longitudinal direction of the column under the action of the telescopic extension and retraction motions of the column. The appliance comprises safety means (37) which are adapted to stop the telescopic motions of the column, in case of defects in the power transmission between a driving motor (15) producing the telescopic motions of the column, and the carriage (22), or if the carriage (22) or a lifting means connected therewith should be stopped by some object in its downward motion.

Abstract: Electromotor driven tensioning and winding device for lashing straps (7) in integral construction, preferably including a tactile three-point measurement sensor (2) in direct contact with a flat side (40) of the lashing strap (7). For this purpose, the measurement sensor (2) includes a sensor bar (30) which is mounted against a compression spring element (31) and has a contact pin (34) which is movable together with the sensor bar (30) and can be pressed against a contact plate (37) fastened to the rear wall (32) of the measurement sensor housing (27).If the desired tension of the lashing strap is reached, the contact pin (34) lies against the contact plate (37). If the contact between the contact plate (37) and the contact pin (34) is interrupted, the drive motor (3) receives a signal to tighten the lashing strap (7) by further winding it onto the wind-up spindle (6). The desired lashing tension of the lashing strap (7) is thus regulated continuously.

Abstract: In mobile laying apparatus for laying an elongated element, such as a cable, in a trench, especially a trench in a sea bed, which apparatus is advanced in a predetermined direction and includes apparatus for digging the trench and ways along which the element slides as it is deposited in the trench, tension control apparatus and a method for preventing the accumulation of such element upstream of the laying apparatus as the element is laid. In the method, a tension force is applied to the element so that the tension thereon upstream of the laying apparatus is at least equal to the tension on the element downstream of the laying apparatus. The tension control apparatus includes motor driven rollers or tracks at the ways which engage the element. The torque which the driving motors apply or alternatively, the energization of the driving motors and the advance of the laying apparatus is controlled by the position of a portion of the element upstream of the laying apparatus.

Abstract: The invention relates to the braking, by means of a control lever, of the winch of a derrick equipped with a band brake and located away from the lever. The lever and the band brake are included in a servo-control circuit and connected by an electric transmission line. A force return is provided on the lever by means of a torque motor receiving the position error signal relative to the mobile end of the band in relation to the control value position given by the lever.

Abstract: A straddle-type crane having the load-lifting mechanism positioned rearwardly of the transversely-extending cross beam used to effect the parallel spacing of the longitudinally-extending upper support beams from which the load-lifting mechanism is supported. Each of the load-lifting mechanisms is laterally movable relative to the upper support beams, from which they are carried, to facilitate the positioning of the load-lifting mechanism relative to the upper support beam and the load which is to be carried therein.

Abstract: A tractor provided with a cable reel at one end and a plow at the trailing end includes a system to monitor tension applied to the cable during underground placement. A capstan engages the cable while driven by a hyraulic motor and the pressure of the fluid supply to the motor is monitored by a pressure transducer. An electrical signal from the pressure transducer is fed to a control which also receives a setpoint signal corresponding to a maximum allowable tension on the cable. An output signal from the control is used to slow down or stop advancing movement of the vehicle and a second signal is used to operate a valve to divert fluid pressure from the hydraulic motor. Tension on the cable extending between the capstan and the reel can be monitored as well as tension on the cable between the capstan and the plow.

Abstract: Apparatus for sensing the tension in a cable and for maintaining the tension between a minimum tension and a maximum tension value comprises a rocker carrying a pulley about which the cable is passed, the rocker being pivotally supported for rotation between first and second rotational positions and being biased toward the first rotational position. Upon tension being applied to the cable, the rocker pivots away from the first position by an amount proporational to the cable tension. Spring biased plungers and associated switches sense the rocker being respectively at the first and second rotational positions and control the tension applied to the cable so as to maintain the tension between the selected minimum and maximum values.

Abstract: An automatic drilling control system is disclosed for a conventional drilling apparatus and rig having a drill line rolled up or fed off the drum during drilling by the engine and extending through a crown block and traveling block to a fixed point providing a dead line. The crown block and traveling block form a pulley system for supporting a drill pipe during drilling. A weight indicator gauge on the drilling console is hydraulically actuated from a pressure sensor connected to the dead line. A conventional brake drum controls the rate of feed out of the drill line to determine the tension of the dead line. A double-acting, fluid-actuated cylinder and piston connected to the brake handle positively move it to control the brake force on the drum. A three-way electric solenoid valve controls the application of pressurized fluid selectively to the piston in response to a pressure transducer in the hydraulic line from the pressure sensor.

Abstract: A constant tension hoisting system is provided for raising and lowering an object between a platform and a surface undergoing vertical motion relative to the platform, such as raising and lowering a lifeboat from a seagoing vessel to the sea in rough weather. The system operates in a normal hoisting mode to raise or lower the object, and in a constant tension mode when the object is supported on the surface. The system is changed from the normal hoisting mode to the constant tension mode at the moment when the object being lowered is first supported by the surface, and a slack condition exists in the cable. The changeover from the normal hoisting mode to the constant tension mode, is performed by a solenoid-operated mode selector responsive to a proximity switch operated by a lever arm engaging the cable. The hoisting system is operated by a single, manually-actuated control lever, which mechanically activates the proximity-type control switches.

Abstract: An apparatus for controlling sway and pendulous motion of suspended loads is disclosed which is particularly suited for embodiment in association with a mobile crane or similar hoist system. The arrangement includes stabilizing cables attached to a load lifting structure or spreader of the crane. The stabilizing cable is reeled and unreeled as the load lifting structure is moved up and down, respectively. The reel for the stabilizing cable is connected to a hydraulic motor which is driven by a pressurized fluid source when the load lifting structure is raised to reel in the stabilizing cable reducing and abating any pendulous motion. Upon unreeling of the stabilizing cable and lowering of the load lifting structure, the fluid flow through the hydraulic motor is reversed and directed through bypass circuitry around the hydraulic motor.

Abstract: Apparatus for controlling a brake on a drawworks having cable wound thereon. A tension gauge detects the tension in the cable which is displayed on a switch gauge. A pulse generator provides periodic pulses to one side of a relay having a set of normally open contacts. When the tension is at or above a preselected level, the other side of the relay is grounded. The relay contacts pulse a pneumatic relay which is connected to a ram that operates the drawworks brakes. When tension is at or below a preselected level, a second pneumatic relay is actuated for maintaining the ram in a brake activating condition. A switch is connected to a third pneumatic relay, which in turn is connected to the ram to permit manual brake activation and deactivation.

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: 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 winch arrangement intended for the rapid shifting of aircraft or other wheeled vehicles which incorporate their own braking system and which may be under the control of an occupant during winching, is so constructed as to provide compensation for wide fluctuations in load on the winch due to a possible lack of coordination between operation of the winch drive and the control of the vehicle. The winched arrangement comprises a drive motor, a winch drum assembly coupled to the drive motor by means of a transmission incorporating a reduction gear said transmission being of relatively high inertia, so that it can run on to drive the winch drum and take up slack in the winch rope in the event of stoppage of the drive motor. The transmission preferably includes an eddy current overload coupling.

Abstract: The method and apparatus for preventing runaway lowering of a hook block in an oil drilling rig characterized by monitoring the instantaneous values of hook load and speed and using these values together with parameters associated with the rig drawworks to calculate an energy value which must be dissipated during a braking stop by the drawworks brake. The brake or an emergency brake associated with the drawworks is automatically actuated when the calculated energy value reaches a predetermined value representative of the maximum energy absorbing capability of the brake. The brake may also be automatically activated when the position of the hook block reaches predetermined upper and lower limits.

Abstract: A switching arrangement for preventing backlash in an automatic angling machine, to activate and deactivate a braking clutch in the angling machine dependent upon whether or not the fishing line issuing from the line reel of the machine is slackened or taut, respectively. A rocker arm sensing the tension in the issuing fish line effects opening and closing of a switch to provide the activation control to the braking clutch. The switching arrangement is advantageously usable with automatic angling machines for providing automatic control of the sinker depth at the end of the line. In combination with automatic angling machines, a sequence of line letting, bottom sensing, limited line hauling, and fishing mode intervals, all functionally associated with the switching arrangement, is made possible.

Abstract: A device for disabling the draw works of a well drilling apparatus responsive to the locking of the drill string by a blow out prevention device. The device comprises an air-actuated valve connected for regulating the flow of air to the air-actuated clutch of the draw works. A second valve regulates the flow of pressurized air to the air actuated valve. The second valve is responsive to the actuation of the blow out prevention device by an accumulator valve.

Abstract: This invention generally relates to a cable recovery device for use on bo a surface ship. The invention compensates for excessive tensions arising in cables carrying submerged loads which are caused by the swell of the ocean acting on the ship, and controls the tension at which the cable is wound. The invention includes a cable winding drum which is rotationally driven by a variable-speed motor, a loop-shaped cable passageway which circumscribes the drum which forms a loop of cable of varying length, and a means for sensing the length of said cable loop and for automatically controlling the speed of the variable speed motor in response thereto. The loop of cable of varying length compensates for excessive cable tensions resulting from the swell of the ship, and allows the cable to be wound around the drum at a desired uniform tension.

Abstract: An apparatus for maintaining tension on a tension cable which is wound on the drum of a winch and connected at one end to a position varying object, especially for maintaining the tension of a power cable leading to a travelling coal extraction machine. The winch, preferably a conventional pressure drive operated hauling coiler can be regulated and driven reversibly and it can produce also at stand-still a continuous rotary moment. A tensioning device having a tensioning pulley 11 is also provided and is subjected to the force of the spring 14, the tension cable 6 being guided around the pulley 11 so that over the spring force a desired nominal tension can be set on the tension cable. Position changes of the tension pulley produce over an actuating linkage 14 a control of the winch so that the tension pulley returns into the original equilibrium position. This control process may be accompanied by running the cable off the winch or hauling it in.

Abstract: Apparatus for suspending a scaffold or the like, used for working on the outer walls of buildings, comprising a capstan made up of four pairs of pulleys driven by an electric motor. The pulleys have grooves for receiving suspension cables, each of which is wound over a pair of pulleys in five turns. On the slack-portion side, each cable is guided over a traverse mechanism, then runs onto a reel mounted via friction couplings on a shaft. This shaft is driven by the motor when the scaffold is raised, while during the descent it is locked by a monodirectional coupling, a driving wheel then being free on the shaft. A safety release device intended to intervene in case of lessening of the tractive force yielded by the friction couplings is combined with the traverse mechanism. If the tension of the slack portion of cable drops below a given threshold, a safety release cuts off the current supply to the motor and actuates an electromagnetic brake.

Abstract: An apparatus is described for detecting a slack cable condition on material handling carriers, hoisting equipment and the like. The device is mounted adjacent the winch drum and is designed for disabling the operation of the winch when the load comes to rest and the cable slackens. When a load is being supported by the cable and the cable is taut, an interface portion of the sensing apparatus is biased to a first position. However, when the load comes to rest and the cable slackens, a bias spring functions to position the interface portion of the sensor to a second position and to preclude further operation of the winch and prevent undesirable cable unwinding.

Abstract: An improved load line sensor comprised of a support frame which clamps to the load line, a sensing unit fixed to the support frame, and a pivotal load line operator attached to the support frame in a close spaced relation to the clamping end thereof. The load line which is threaded through the pivotal operator is slightly deformed thereby so that line tension imparts a torque to the operator which reacts against the load sensing unit fixed to the support frame. The load line operator preferably has roller contacts wherein the pivoting and roller action of the operator minimizes the frictional influences which impair the operation of conventional devices.