1. 6-prong radial expansion system

The main body of the equipment is a circular expansion body, with 6 sliding rails set radially. Each sliding rail is embedded with expandable prongs that can slide independently. Through hydraulic or pneumatic drive, the 6 prongs expand synchronously to form a uniform radial force distribution, avoiding damage to the inner wall of the silicone rubber three-finger sleeve caused by local stress concentration.

The surface of the expandable prongs is covered with elastic fiber sleeves (such as high-strength nylon fabric or silicone composite layers), providing buffering protection when in direct contact with the inner wall of the three-finger sleeve, preventing scratches and tears.

2. Flexible protection and withdrawal mechanism

Some models adopt a dual protection layer design: the inner layer is a detachable flexible fabric sleeve (such as a cloth sleeve), and the outer layer is an elastic fiber sleeve. During expansion, the hydraulic cylinder pushes the conical mold into the fabric sleeve to achieve non-contact expansion. During withdrawal, the fabric sleeve is pulled back in the opposite direction synchronously to detach from the three-finger sleeve, avoiding friction.

The 6-prong design allows for more precise control of the expansion path, and in combination with the numerical control system, it can achieve ±0.3mm radial accuracy, ensuring that the three-finger sleeve tightly adheres to the cable bifurcation point after contraction.

II. Technical Advantages and Innovations

1. Uniform expansion and seamless protection

The synchronous expansion of 6 prongs can cover a larger contact area (compared to traditional 3-prong models), reducing the pressure per unit area, especially suitable for processing three-finger sleeves of large specifications (such as 110KV), avoiding local overload deformation caused by insufficient prong number in traditional equipment.

The dual protection of elastic fiber sleeves and flexible fabric sleeves can reduce the inner wall wear rate by more than 90%, improving sealing performance and insulation life.

2. Modularization and efficient production

By replacing expansion prong molds of different sizes (such as arc and length of the prong head), the same equipment can be adapted for processing three-finger sleeves of 1KV-110KV cables, achieving "one machine for multiple uses".

Automated models support the expansion operation of 2-3 three-finger sleeves per minute, and a single person can complete the positioning, expansion, and insertion of the support tube throughout the process, increasing efficiency by 40%.

III. Typical Application Scenarios

1. Power cable bifurcation sealing

Mainly used for the pre-expansion of three-finger sleeves at the bifurcation point of 10KV-35KV three-core cable terminal heads to ensure the tight adhesion of the insulation layer to the copper shielding layer and the outer diameter of the main insulation, meeting IP68 waterproof and dustproof requirements.

2. Adaptability to special environments

In scenarios such as photovoltaic power stations and rail transit, it is necessary to cope with harsh conditions such as high and low temperatures (-55℃~150℃) and salt spray corrosion. The silicone rubber three-finger sleeves processed by the 6-prong expansion machine do not have inner wall damage, and can maintain elastic sealing performance for a long time.