While all of the Vulcan air/steam hammers have the same basic operating principle, there are variations within the various lines that enable the contractor to select the optimum hammer for the application. These variations are as follows: Three (3) Foot Stroke Hammers: This includes hammers with 36″ (914mm) stroke. These are the original Vulcan air/steam hammers; they combine a heavy weight with a low striking velocity, and are especially apt for concrete piles where tension cracking is always a danger. These include the #1, 306, 08, 010, 012, 014, 016, 320, and 330 hammers. Five (5) Foot Stroke Hammers: These all have a stroke of 60″ (1524mm). These were designed to give the contractor a relatively light hammer and thus enable the contractor to use lighter piling rigs. They are also effective with steel piling. These include the 505, 506, 508, 510, 512, 520, 525, 530 and 535 hammers.
The cycle begins at impact,the valve is rotated in such a way as to admit steam or air into the cylinder and below the piston. This accelerates the ram upward as shown in View 1. This continues until the exhaust wedge on the slide bar actuates the trip and rotates the valve to close off the steam or air inlet and opens the area of the cylinder below the piston to the atmosphere where the compressed air or steam is exhausted. The ram continues its free rise upward, decelerating with gravity until the top of the piston passes the relief ports and closes in the dashpot at the top of the cylinder. This trapped air, shown in View 2, compresses and brings the rising ram to a halt. The ram then makes a free drop to impact. Shortly before impact the intake wedge rotates the valve to admit steam or air to the cylinder and the cycle starts once again.