Automatic Hydraulic Shaft Puller

Challenge: Develop a machine to pull a mandrel shaft out of a larger cylinder.

Solution: The machine consists of a hydraulic cylinder press mounted in a pulling fixture with a power unit to provide hydraulic pressure to the cylinder. The fixture has bolting hardware to mount the tool to the face of the master cylinder without damaging surrounding components. Lifting eyes provide a pick point for handling the tool. The tool incorporates hydraulic cylinders to generate up to 10,000 pounds of axial force on the mandrel shaft.

A series of hydraulic cylinders with gripper jaws lock onto the shaft. The clamp is capable of creating up to 10,000 pounds of force on the shaft, depending on the surface finish and fit of the bar in the clamp. With the jaws engaged, the press cylinders pull the shaft out of the cylinder one stroke length. The jaws then release the bar, and the press cylinders retract to ready the pull action again.

This process is repeated by an integrated control unit. The control unit is mounted on a rolling cart for mobility and includes a power unit for the hydraulic system, as well as the logic control and user interface for the machine.

The user interface consists of a small LCD screen with buttons to allow the operator to cycle the valves independently, or to start the process working automatically. In automatic mode, the cylinders cycle in turn - clamp, pull, release, retract, and so on.

The operator is responsible for monitoring the progress of the pulling operation and safely handling the shaft as it comes out of the cylinder. A hydraulic lift table is included to allow the operator to lift the tool to the work on site.