Auto Hairpin Bender

Structural Form: Servo length fixing and material returning; the hydraulic system adopts a fixed-displacement vane pump, and swing cylinders drive bending. The whole machine consists of a material rack, a cutting machine, and a bending machine. The bending machine can move along the length direction to realize the production of workpieces with different lengths. Automatic cycle process: Straightening → Feeding → Compacting → Cutting → Upper bending → Core pulling → Unclamping → Unloading → Resetting.

Uncoiling Device:

2.1 The external core-pulling motor-driven material rack drives the material tray to uncoil via a motor with a reducer, and travel switches control stopping and uncoiling.

[Patent No.: 201920603858.5]

2.2 The external core-pulling non-driven material rack relies on the power of the feeding device to drive the material tray for uncoiling and stopping, suitable for large pipe diameters and thick wall thicknesses. (Optional)

2.3 The internal core-pulling material rack uses the power of the feeding device to drive the material tray for uncoiling and stopping. The material tray is directly placed horizontally on the ground and can be stacked in multiple layers, featuring a simple and durable structure, suitable for small pipe diameters. (Optional)

Straightening Device: Straightening rollers are arranged crosswise on horizontal and vertical planes to round and straighten copper pipes from two planes. Each copper pipe is equipped with 4 rounding rollers and 12 straightening rollers, among which 1 rounding roller and 4 straightening rollers are adjusted via eccentric shafts to ensure the straightness of hairpin pipes.

Material Exhaustion Detection: Adopts photoelectric switch detection, installed in front of the straightening rollers.

Feeding Device: Uses friction feeding method with a structural form of cylinder-pressed timing belt feeding. Each group of timing belts is equipped with an independent cylinder. During feeding, the cylinder compacts the timing belt, and the upper and lower timing belts clamp one copper pipe for friction feeding. When feeding is nearly in place, the feeding speed switches from fast to slow, and the compaction cylinder on the timing belt switches from high pressure to low pressure. Once a copper pipe is fully in place, the cylinder of that group loses pressure to avoid bending caused by copper pipe friction. The feeding is driven by a hydraulic oil motor, and high-low speed hydraulic valves easily realize the working cycle of feeding from slow speed (startup) → fast speed → slow speed (in place) to ensure high efficiency and workpiece quality.

Feeding In-place Detection: Detected by inductive switches.

Copper Pipe Cutting Device: Uses external hob to cut copper pipes, with oil mist lubrication during cutting. The cutting depth of each copper pipe can be adjusted separately to ensure synchronous cutting of copper pipes with minimal necking. After cutting, the feeding timing belt reverses to separate the copper pipes.

Bending Device: Composed of bending clamping, bending rotation, and bending support die lifting/lowering components. To ensure reliable clamping during bending, one bending die is used for each copper pipe, and each bending die is equipped with an independent clamping cylinder. The bending rotation device is driven by a swing cylinder to rotate the bending device. The bending support die is installed on a fixed plate driven by two cylinders: when the support die is lowered, feeding or unloading can be performed; when the die plate is raised, it assists the bending die to complete pipe bending.

Unloading, Core Pulling, and Mandrel Device: The above devices are all installed on guide rails. After the copper pipe is bent, with the bending die in the clamped state, the movable mandrel is driven by a cylinder to withdraw from the bending tangent point, then unloading is performed. The servo motor drives the unloading seat forward quickly via a ball screw to unload the hairpin pipe. Connected to the movable mandrel is a connecting rod made of thick-walled cold-drawn seamless steel pipe. The machine is equipped with an oil mist lubricator and a distributor. Through the distributor and small holes on the connecting rod, oil mist is sprayed on the inner wall after the die clamps the copper pipe and during bending to ensure bending quality.

Hairpin Pipe Length Adjustment Device: When the length specification of the hairpin pipe changes, adjustment shall be made via the length adjustment device, which consists of the following parts:

10.1 Bending Length Adjustment: Used to adjust the length of the workpiece after bending. The positioning of the unloading seat is driven by a servo motor via a ball screw; the positioning of the bending machine is realized by a servo motor driving a lead screw, and it is fixed to the base by an automatic clamping device after being in place.

10.2 Guide Rack and Receiver Adjustment Device: According to different lengths of hairpin pipes, the equipment is equipped with guide racks of different lengths. The receiver is driven by a cylinder, and the receiving arms are installed on a long shaft. The receiving arms can slide along the long shaft to change the distance between them, or the number of receiving arms can be increased to meet the receiving requirements of workpieces with different lengths.

Safety Light Curtains: Installed on both sides of the equipment.

Hydraulic Station: Arranged inside the frame-type machine base, adopting a fixed-displacement vane pump equipped with an air cooler.