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Note: a field service manual for these hammers is available in the vulcanhammer.info Guide, link above.
Although the California series hammers were successful and a definite expansion of Vulcan's product line, they suffered from two major weaknesses:
Vulcan had prepared to replace the "G" in 1941, but the intervention of World War II put a stop to the project. It wasn't until 1955 that Vulcan introduced the DGH-100 hammer (shown at right.) The DGH series of hammers made several advances:
Some of these features are illustrated below, including (from left to right) "pants" for driving sheet piling (see the DGH-900 photo below,) the Universal Backhoe Adapter for use with backhoes and excavators, and leader angles for the U-type leaders common with other Vulcan hammers.
The Universal Backhoe Adapter enabled the DGH-100 to be used with a wide variety of backhoes and excavators without having to develop a custom adapter for each make and model. One of the remarkable things about the DGH-100 is that it was never completely eliminated by hydraulic breakers, which are generally able to use the excavator's own hydraulic power and eliminate the need for an additional compressor. This is a testament to the simplicity, durability and performance of the product. DGH hammers can be operated at angles down to horizontal, a capability unique for Vulcan products.
Right: the Universal Backhoe Adapter at the Special Products Division, where it was manufactured. The hammer is laying on the pallet, and the adapter is upright, bolted to the hammer. Into the slots are welded bushings for the pins which affixed the assembly to the backhoe or excavator. The bushings were custom fitted into the slots for the proper position.
In the 1970's, Vulcan developed an "Auto-Stop" feature which stopped the hammer when not applied against resistance (U.S. Patents 3,645,342 and 3,782,483.)
A DGH-100 hammer mounted on a backhoe.
Vulcan was eager to market the DGH hammers as broadly as possible. Below are two joint venture products with the Gardner-Denver Air-Trac (the "Trac-Hammer") and the Pettibone Speed Swing.
Vulcan also developed a DGH-900 hammer, with a larger ram, but this was no where near as successful as the DGH-100. Vulcan continued to produce and market these hammers until the company was divested in 1996. IHC/Vulcan Foundation Equipment discontinued them in 2005, but the current Vulcan Foundation Equipment provides parts and service for DGH-100 and DGH-900 hammers.
Below: the DGH-900 in action, driving sheet piling. Unfortunately it never achieved the popularity of the MKT "B" hammers or the MKT #7 with which it was designed to compete.