7.2 Wire Rope Pull-Lifts, Winches & Jacks

Wire-rope Pullers, Winches and Jacks

These appliances create force in different ways. A jaw-type puller grips a separate rope, a winch stores rope on a drum, and a jack raises through a screw or hydraulic ram. Each has configuration-specific ratings and holding limitations.

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Jaw-type Wire-rope Pullers

A portable puller uses alternating jaw blocks to grip and advance a manufacturer-specified rope. The rope is part of the system: diameter, construction, end condition and cleanliness must match the machine. Ordinary crane rope or a kinked substitute may not grip correctly.

Inspect the body, pins, handle, jaws, rope, hooks and anchorage. Feed rope in the instructed direction and keep it aligned with the machine. Side pull can damage the casing or create an unstable anchor reaction.

Many pullers use a sacrificial shear pin or other overload feature in the operating handle. Its threshold and behaviour are model-specific; 125%-150% of WLL is not a universal value. A sheared pin does not prove that the rope, anchor and machine are undamaged, and it must be replaced only with the specified part. Follow the manual for controlled lowering and inspection after an overload event.

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Winches and Drums

A winch may lift or pull only within the duty and orientation for which it is rated. Confirm whether the rating applies to the first rope layer, top layer, line pull or suspended lifting. As rope builds on the drum, effective radius rises and available line pull commonly falls.

The rope must be anchored and reeved as designed, with the required number of turns remaining at maximum payout. The tail attachment is normally not intended to carry the full line load by itself. The number of dead turns is manufacturer- and design-specific; “two or three” is not a universal rule.

Drum groove, rope diameter, flange height and spooling system must match. Do not guide a loaded rope by hand or stand in a bight. Keep the rope under appropriate tension during spooling and prevent cross-winding, crushing and loose buried wraps.

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Fleet Angle

Fleet angle is the lateral angle between the rope path and the drum's normal lead. Too large an angle can cause poor spooling, flange wear and crushing; too small an angle on some plain drums may prevent the rope traversing properly. Values such as 1.5° for plain drums and 2° for grooved drums are common design guidance, not universal limits in BS EN 14492 for every winch installation.

Use the winch, drum and rope manufacturer's permitted range and measuring convention. Check the lead sheave position, drum width and distance geometrically. A level-wind mechanism may control spooling but has its own setup and inspection needs.

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Jacks

A screw jack raises through a threaded mechanism; a hydraulic jack uses fluid pressure and a ram. The base must be fully supported on material that will not settle or punch through. Keep the load applied to the designated head or toe, centred as far as the product requires.

Some toe jacks have different marked capacities at head and toe because the toe creates an eccentric load path. Do not assume that every toe rating is 50% of head capacity. Read both markings and the permitted stroke. Never pack on top of a small toe or use the jack horizontally unless designed for it.

A hydraulic jack can lose height through leakage or valve movement. Once raised, support the load with rated stands, cribbing or the jack's designed mechanical lock before anyone enters the danger area. The jack raises or positions; it is not automatically a long-term support.

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Inspection and Use Controls

For pullers and winches, inspect rope for broken wires, corrosion, kinks, crushing and termination damage. Check brakes, pawls, controls, guards, drum, anchorage and limit devices. For hydraulic jacks, inspect leaks, ram condition, base, toe or head, relief device and mechanical lock. For screw jacks, examine threads, nut wear and handle.

Verify the reaction path as carefully as the appliance WLL. A 3 t puller attached to a 1 t anchor is a 1 t system at most, subject to configuration. Calculate line parts and sheave reactions; a redirecting sheave can impose more than one line pull on its anchorage.

Keep people clear of ropes, handles and the possible path of a released load. Avoid shock, handle extensions and bypassed relief or overload devices. After overload, jam, rope crossover or structural impact, withdraw the equipment for competent assessment.

Under LOLER, equipment used for lifting loads normally follows the 12-month default interval, or six months for lifting people, unless an examination scheme sets another. Accessories such as separate shackles and lifting slings retain their own interval.

The Foundation decision is to verify machine, rope, anchor, geometry and holding method as one system.

System Check