Import A2b Crane Limit Switch — Buy in wholesale FOB from Supplier in China

The GJ-type A2b crane limit switch from Liaoning Mingcheng Trade Co., Ltd is an electrical automatic protection device designed to prevent overwinding of lifting wire rope on hoisting drums. The switch operates through a weighted hammer mechanism, where vertical hook movement engages or disengages the electrical contacts to cut power and activate braking systems. This interrupts the hoist motor supply when the hook reaches predetermined upper or lower limits, thereby preventing rope over-volume and controlling lift height within safe operational bounds. The design relies purely on mechanical interaction between the moving hook assembly and the switch actuator, with no programmable logic or sensor-based feedback.

The hammer-type actuation principle places this device in the category of direct-acting limit switches rather than rotary or lever-arm encoders. Contact rating, enclosure ingress protection, and mechanical durability are critical specifications for crane duty, yet the listing provides no quantitative data on these parameters. Standard GJ-type switches for Chinese domestic cranes typically employ silver alloy contacts rated for AC-15 operational categories, with enclosures at minimum IP54 for indoor crane applications and IP65 for outdoor or foundry environments. Cable entry is usually via M20 or M25 threaded glands, and mounting accommodates vertical or horizontal orientation on the crane trolley or drum support structure. The switch body is commonly cast aluminium or engineering plastic, depending on duty class and cost tier.

Buyers for this product include overhead crane manufacturers, port crane refurbishment contractors, steel mill maintenance departments, and mining hoist operators. The switch serves as a mandatory safety interlock on electric wire rope hoists, chain hoists, and winch systems across single-girder, double-girder, and gantry crane configurations. Liaoning Mingcheng Trade Co., Ltd is located in Fushun City, Liaoning Province, an industrial centre with historical concentration in heavy machinery and coal mining equipment. The listing does not state contact electrical ratings, hammer weight options, adjustment range, or compliance with GB/T or IEC standards. Buyers must confirm these directly with the supplier before specification in new crane builds or retrofit programmes.

Liaoning Mingcheng Trade Co., Ltd is registered at No.103, Unit 1, Building 23, Zhandong Street, Fushun City, Liaoning Province 113000, China. Fushun is an established heavy industrial centre in northeast China, historically associated with coal mining, petrochemical refining, and heavy machinery manufacturing. The supplier's trust tier is designated as harbor, with zero recorded response rate and zero average response hours on the platform, indicating no measurable buyer engagement history. The company name includes Trade Co., Ltd, suggesting commercial distribution rather than manufacturing origin, though this is not definitive.

No information is provided about year of establishment, registered capital, employee count, factory ownership, quality system certification, or named crane industry customers. The address format indicates a multi-unit commercial or residential building rather than a dedicated industrial park location. Buyers should verify whether Liaoning Mingcheng Trade Co., Ltd manufactures the GJ-type switch under its own design, sources from a Liaoning-based OEM, or trades as a distributor. Direct enquiry should cover company registration details, VAT invoice capability, export licence status, and whether technical support for installation and adjustment is provided.