UB-12 Clevis

 

Item	Specifications
Model	UB-12 Parallel Clevis
Type	Right-angle Connection Clevis
Nominal Breaking Load	120 kN
Material	Hot-dip galvanized steel, stainless steel closing pin included
Corrosion Resistance	Hot-dip galvanized coating thickness ≥ 65 μm
Plate Width	12 mm
Connection Aperture	16 mm, compatible with standard M16 bolts
Overall Dimensions	80 mm (Length) × 12 mm (Width) × 8 mm (Thickness)
Primary Applications	Parallel connection of insulator strings for 10kV-35kV transmission lines, substation equipment mounting, and cable terminal support

UB-12 parallel clevis is a high-load right-angle power fitting widely used in overhead power lines and substation projects. It serves as a stable connecting component between insulator strings and other line hardware, securing links between various power equipment and fittings while bearing corresponding tensile loads. With a rated breaking load of 120 kN, it is designed for connection positions that require relatively high bearing capacity. For on-site operation, the clevis maintains sufficient strength and toughness to withstand tensile loads under different line working conditions, without deformation or fracture during long-term service.

The model follows standard power fitting naming conventions: the letter "U" refers to its U-shaped connection structure, "B" stands for plate-type clevis classification, and the number "12" corresponds to its 120kN nominal breaking load grade. The upper end connects to tower crossarms with long-shank bolts to support double shear plane loads, while the lower end adopts a slotted connection design, with two rotation axes set at a 90-degree angle. It can be used to assemble insulators, suspension clamps, strain clamps and protective fittings into complete suspension or tension strings for transmission lines.

There are several derivative configurations of the UB-12 series tailored for different application scenarios. The standard UB-12 model has a 120kN breaking load and hot-dip galvanized coating over 65μm thick, suitable for conventional transmission line insulator string connection. The UB-12Z variant features a reinforced straight-plate structure with higher structural rigidity, designed for scenarios with higher impact load requirements. For heavy-load projects, an upgraded thickened version with reinforced plate body and connection holes is available, offering higher mechanical stability for heavy-duty line applications.

Multiple factors may cause faults during long-term service, and timely maintenance is required to ensure stable line operation. Corrosion damage is the most common issue, mainly caused by insufficient galvanized coating quality, or long-term exposure to high-humidity, saline-alkali or industrial polluted environments. When the zinc coating peels off or the steel base corrodes, targeted repair or replacement is needed. Mechanical damage such as cracks, deformation on the clevis body, worn connection hole edges or oversized bolt clearance is usually caused by improper installation operation, or long-term vibration and wind load from conductors during operation. Connection failures including loose or broken bolts mostly result from mismatched fitting specifications or insufficient installation torque. In addition, dimensional deviation caused by poor processing accuracy or transportation deformation will lead to poor fitting with other hardware and unstable connection.

Regular inspection of the galvanized coating is a core part of daily maintenance, as anti-corrosion performance directly determines the service life of the clevis. Inspectors can use a thickness gauge to measure zinc coating thickness at multiple evenly distributed points on the clevis surface, including the outer side, inner side and areas around bolt holes. According to standard requirements, a coating thickness of no less than 65μm meets basic anti-corrosion needs, while for coastal or industrial high-corrosion environments, a thickness of 85μm or above is recommended. If the coating thickness falls below the standard or shows obvious plating leakage, anti-corrosion performance will decrease significantly with high rust risk, and in this case, coating repair or product replacement is recommended.