Rebar Bending Machine

Overview

A rebar bending machine bends reinforcement steel bars to the angles and shapes required for concrete reinforcement cages and assemblies. The machine consists of a fixed die on the work table, a rotating die disc on the lever arm, and a pivot pin around which the rebar is bent. The operator manually positions the rebar against the fixed die, presses the foot pedal to engage the drive, and the rotating die sweeps the rebar around the fixed pin to the desired angle, then releases and cycles back for the next bend.

The machine is essential in precast concrete shops and on large job sites where hundreds of bars must be bent to standard shapes, hooks, bends at 45, 90, and 135 degrees, with high accuracy and repeatability. A skilled operator can bend and flip bars in a rhythmic cycle, producing 50–100 bars per hour.

How it works

The Electric Motor, a compact three-phase or single-phase electric motor rated 3–7.5 kW, runs continuously. Its shaft connects through a rebar-bending-machine-flexible-coupling to the Gearbox & Speed Reduction, which contains helical Gear Pair reducing the motor's 1,450 rpm down to 70–150 rpm at the output shaft.

The gearbox output drives the Lever Shaft, which carries the Lever Arm. The lever arm rotates slowly and is always running when the motor is on. At the end of the lever arm sits the Rotating Die Disc, a hardened steel disc sized for the rebar diameter being bent.

On the work table sits the Fixed Die, a matching hardened steel die bolted to the Bending Head Casting. Between them is the Fixed Pivot Pin, a fixed steel pin around which the rebar bends. The operator inserts a straight rebar through the Guide Pin locators on the table, positions it against the fixed die and pivot pin, and then presses the Foot Pedal.

The foot pedal is mechanically linked to the Friction Clutch via a Connecting Rod. Pressing the pedal engages the clutch, locking the lever arm output to the continuously running gearbox. The lever arm sweeps the rotating die forward, dragging the rebar around the fixed pivot pin in a smooth arc. The operator watches the angle, and releases the pedal when the desired bend angle is reached, typically marked by an Angle Stop that blocks the lever arm.

The friction clutch disengages as soon as the pedal is released, and a Coil Spring returns the lever arm back to its starting position, ready for the next cycle. The rebar stays bent because the bend is permanent, the yield point of the steel has been exceeded, and the operator removes it from the dies and positions the next bar.

Different rebar diameters require different Die & Bending Pin Set sets, separate fixed and rotating dies machined for 6 mm, 10 mm, 16 mm, 20 mm, 25 mm, and 32 mm bars. Changing dies takes 10–15 minutes. The Stop Block on the table limits how far the rebar can be pushed under the dies, protecting the operator's hands and ensuring consistent bending geometry.

Smaller machines bend up to 16 mm bar; larger industrial units handle 32 mm or even larger special steel. The torque in the system is substantial, a 20 mm rebar bar can require 400–600 Nm of bending torque, so the Base Plate must be heavily bolted to the floor to prevent the whole machine from rocking backward under load.