The Kowan Still Worker is a hydraulically powered, staticload steel pile pressing machine. It was developed in Japan in the early 1970's in response to severe constructional and environmental problems and initially to overcome the difficulty of installing steel sheet piles in high-density inner city areas where the use of conventional equipment such as hydraulic vibrators and hydraulic drop hammers generated unacceptable levels of vibration and noise. The Still Worker is able to press steel sheet piles as close as 500mm to an existing structure, providing an extremely quiet method of operation and almost entirely free from vibration. Operated at ground level and by a wireless radio control device, the Still Worker is the safest and most environment-friendly system for installing steel sheet piles today. The main features and benefits of the Still Worker are:
- Virtually noise and vibration free means installation of steel piles as close as 500mm to existing structures or services
- The Still Worker operates at ground level with no piling gates making it a very safe method of operation.
- Uses a wireless radio control providing a broad range of vision for the operator and a safe working environment.
- Still Worker is light and compact requiring only a small crane for pile pitching.
- It is ideal for height restricted sites.
- It is also an extremely good extraction machine.
With the introduction of new noise and vibration legislation by the Japanese government in the mid 1970's the demand for pile pressing machines grew very quickly and by 1990, there were more than 2000 machines in operation. At this time, Kowan has decided to start exporting their product and chose UK piling equipment specialists Watson and Hillhouse as their exclusive global distributor. Watson and Hillhouse began marketing and promoting the Still Worker across Europe and although it proved difficult to market a revolutionary product like the Still Worker within different countries with differing cultures and contracting systems, the unique benefits that the Still Worker affords the client and contractor alike ensured sales success and resulted in machines being sold right across Europe including the UK, Ireland, Germany, France, Italy, Holland, Switzerland, Denmark, and Poland, with 1000's of projects having been completed with this revolutionary technique.
In the last 3 years, following a substantial marketing campaign around 10 machines have now been sold to Russia. Beyond Europe, pile pressing machines are also in use in the USA but the biggest single machine order came in 2011 when alongside their dealer Suretech, the construction and engineering company Navayuga purchased the largest machine in the Kowan product range, a PZ-1200 Still Worker for the installation of 1200mm diameter interlocking steel tubular piles for their project at Machilipatnam Port for the construction of a structural breakwater.
Whilst the first Still Workers produced were for the installation of steel sheet piles, over the past 10 years Kowan have developed machines for installing interlocking steel tubular piles for the installation of contiguous piled retaining / load bearing walls. The machines are now available for the installation of tube piles from 600mm diameter to 1200mm diameter with pressing forces from 110 ton up to 150 ton. There is also now a wide range of sheet pile machines in the Kowan product range that can press from 80ton to 150 ton; U sheet pile machines that can install from 400mm wide up to 750mm wide piles and Z sheet pile machines that can install piles from 575mm wide up to 708mm wide. Kowan has also developed an insitu 'auger crush' system that is available on some models which enables sheet piles to be pressed into very hard soil strata, the auger, fitted to the Still Worker is positioned inside the pan of the sheet pile and crushes the soil ahead of the pile. An alternative to the auger crush is to use high pressure water jetting which can be used to ensure pile installation into stiff cohesive soils and dense granular soils, these bespoke jetters developed specifically for pile pressing are also available from Watson and Hillhouse / Suretech as well as two jetting options; the steel lance system or the Kowan Water Jet Reel which again is fitted to the machine and is synchronized with the press.
Each Still Worker also has the exclusive mast tilting device and is a standard feature with each machine, the benefits of the mast tilt device are:
- the mast/chuck can incline forwards and backwards by 5 degrees
- more accurate and efficient pile installation
- makes self-travelling easier and quicker
- makes working on gradients much easier
Watson and Hillhouse and their Indian dealer Suretech are very confident that the Still Worker will soon become common place for the installation of both steel sheet piles and steel tubular piles in the major towns and cities across India as the environmental impact of using the traditional vibratory and impact equipment types will become unacceptable when piling in very sensitive locations.