Case Study

Advancing Pile Driving Tech for Speed and Safety

Case Study: Advancing Pile Driving Tech for Speed and Safety


Today's piling projects are becoming more and more complex due to spatial restrictions, environmental conditions, noise and vibratory restraints, and much more. As the challenges of pile driving continue to evolve, the equipment must follow suit.

Hercules Machinery Corporation (HMC) is a leading provider of modern and comprehensive piling solutions with a focus on safer buildings, less lifecycle costs, and fewer repairs.

While redesigning their entire rotary assembly in prep for releasing their new Sonic SideGrip® Vibratory Pile Driver attachment, HMC asked DSTI to provide its expertise to improve a key component within their equipment - the rotary union.

The Sonic SideGrip® requires five independent hydraulic fluid lines with pressures ranging from 150 to 5,000 PSI. The fluid travels from the excavator's onboard hydraulic system into the rotary union then exits to different components within the attachment. This generates the hydraulic power necessary for the attachment to safely and quickly pick up, unload, place, drive and extract piling for a wide variety of job sites and soil conditions.

The rotary union would need to endure equipment vibrations, provide owners and operators with a long service-life, and fit within HMC's tight space constraints.


DSTI's solution features a heavy-duty construction and corrosion-resistant plating capable of withstanding the harsh operating environments, and the same field-proven sealing technology found in many of DSTI's standard product lines.

Due to HMC's space restrictions, DSTI engineers ran into a few challenges themselves. In order to keep the outside diameter and length to a minimum, an angled port was incorporated into the design and a large high-pressure port in the housing was split into two smaller diameter channels while still matching the flow rate as if a larger port was used. Both of these features allowed for a more efficient use of the product’s space and helped reduce the overall size and cost of the rotary union.


Working directly with HMC's engineering team, DSTI was able to provide a custom, 5-passage rotary union that arrives fully assembled and tested for direct integration into HMC's equipment. Prototype units were tested and ran successfully in the application, validating the quality and performance before larger production runs begin.

Results Overview

  • Face-to-face customer visits strengthened the relationship and allowed DSTI to identify crucial engineering and commercial details
  • Maximized attachment's performance and profit by providing unrestricted 360 degrees continuously rotation
  • A complete rotary union assembly fully tested and ready to install
  • Shaft, housing and cap coated with specialized QPQ plating for surface hardening to improve corrosion, wear, heat, and friction resistance
  • DSTI's exclusive sealing system optimized for high reliability and performance
We can confidently say a DSTI hydraulic rotary union has not failed in any of our products. During the redesign of our Sonic SideGrip®, DSTI took the time to investigate various purchasing scenarios and options that catered to our needs.

In the end, they were able to achieve costing goals while still providing us with a superior product. DSTI is very knowledgeable when it comes to hydraulic swivels joints and their team is always a pleasure to work with.
Billie Saalfrank Engineering Project Manager at Hercules Machinery Corporation

Additional Resources


Our experts are here for you!

Contact Us