Wednesday, 7 August 2019

Digga drive key features (up to PD50)

Digga’s range of screw anchor and auger drives are the ultimate in performance, quality and cost effectiveness. With over 30 years of design and development, working in the field and listening to the needs of our customers to exceed their expectations.

All Digga drive units are manufactured in Australia, by Digga - from the hood on the drive to the gear box and Eaton motor. Our drives feature key design modifications to stand them apart from the competition:

Integrated motor and output housing unit

Our custom designed hydraulic motors were developed in conjunction with Eaton, using Eaton Geroler technology. Not satisfied with an off-the-shelf motor we developed the design specifically for the earth moving industry; significantly reducing the weight and overall length of the drive unit by integrating the hydraulic motor into the actual housing.
Merging the motor with the input housing creates a direct connection to the gearset and eliminates the need for several gearbox components. In turn, there are less moving parts and fewer potential leak points.
It also means we have been able to position the hydraulic motor ports in a more practical location; maximising manoeuvrability when drilling and offering greater protection to hoses and fittings during transport and storage.

    Less maintenance and a compact design

    Our gearboxes are made in-house at our factory in Queensland, Australia. Gears are precision machined from high grade alloy steel, specifically formulated for the manufacture of high performance gears in the earth moving industry.
    The compact design of our gear set allows for greater length under the drive, for augers or pile installation. As our drives can go down the hole they provide added depth when drilling allowing you to work more efficiently.

      Two piece shaft design with the highest side load ratings

      Digga drives have more than double the side load capacity of any other gearbox on the market. Under toque load, the Digga two piece shaft design ensures there is no increased load on the bearings. The bearings do the job they were designed for, efficiently maintaining axial and side loading.
      Making the Digga shaft a separate component to the planetary carrier, the planetary gears are isolated from the pushing, pulling and bending forces generated by the machine.
      This is highly beneficial for the operator should there be any side loading; the Digga two piece shaft design ensures there is no increased load on the bearings and the gears are protected, saving you on potential costly repairs.
      Digga drives have the highest shaft pullout rating in the industry with a heavy-duty custom designed lock-nut, and a lifetime warranty on shaft pullout.

      two piece shaft design - digga auger drive

      Highest side load ratings

      Digga drives have more than double the side load capacity of any other gearbox on the market. Under toque load, the Digga two peice shaft design ensures there is no increased load on the bearing. The bearings do the job they were designed for, efficiently maintaining axial and side loading.

      Extensive warranty

      With a 3 year motor warranty and 5 year gearbox warranty, our drives are backed with outstanding quality.
      Customer warranty - digga drive unit - motor warranty
      For more information on the different models in our range of auger and screw anchor drives please visit our website: www.digga.com

      Tuesday, 6 August 2019

      The evolution of screw piling.

      It is said that the first recorded use of a screw pile was by Alexander Mitchell, a brick maker and engineer from Ireland who coined the term ‘screw-pile’ in 1833.

      Initially the concept of screw piling was used to provide solid foundations for lighthouses in soft soil and provided enough holding power to safely moor ships in the harbour.

      The original screw pile concept cannot be officially confirmed but in the April 1848 issue of the Civil Engineer and Architects Journal the article highlights the mechanics of the bearing power of screw moorings and screw piles which Alexander Mitchell is argued to have introduced: 
      "The origin of the screw-pile was the screw mooring, which was designed for the purpose of obtaining, for an especial purpose, a greater holding power than was possessed by either the ordinary pile or any of the usual mooring -anchor blocks, of however large dimensions.... whether this broad spiral flange, [or ’ground screw,’ as it may be termed] were fixed upon a spindle, and forcibly propelled by rotary motion to a certain depth into the ground, an enormous force would be required to extract it by direct tension"
      It wasn’t long after this that screw piles were being installed all around the coast of England and Ireland and soon after that the method was being exported to the United States of America.

      During Mitchell’s era, the design and application of screw piles was by trial and error and it wasn’t until later down the line that the strategic use of screw piles begins to take place.

      Screw piles were used to support tension loads, compression loads, overturning moments and combined loading – as we see in many modern foundations today.
      Over the last 60 years while screw piles have often been associated with the electric utility industry as helical anchors for guy wires for poles and towers, they have found their way into nearly every aspect of civil construction: building foundation support for new construction, pedestrian bridges and walkways in environmentally sensitive wetlands and other areas, slope stability repair, tiebacks in temporary earth support, underpinning foundations for temporary structures, foundations for light and signage structures and wind generators, tension anchors for transmission towers and cell towers, underpinning of existing structures, foundations of bridge foundations, and a variety of other geotechnical applications.

      A key feature of screw piles is the ability to monitor the installation of every pile by careful monitoring of the installation torque and rotation as the pile advances. Even though the required installation torque relates to the specific geometry of the pile, including the helical sections and the central shaft, the torque also relates to the interaction between the screw pile and the soil. Therefore, the resulting installation torque record provides a means of direct quality control and assurance that can be used to verify soil conditions at each pile location, as well as to provide an estimate of pile capacity through correlations between torque and capacity. This is particularly important since it is usually not possible to have a soil boring at each pile location. The installation torque provides a specific log of the conditions at each location and allows for adjustments to be made to ensure that the desired pile capacity will be reached. This also means that each pile is tested and in most cases can be used to immediately support design loads.
      Australian screw piling expert and business owner Brodie Houghton of Solidity from Victoria, told Digga that they see helical piling as the next big shift in building technology, with a much needed flow on effect to both profitability of the building industry and housing affordability in general. Houghton explained: 
      "Builders who are conscientious of project economics are already making the shift to helical piling in hordes. Screw piling [with Solidity*] not only eliminates costly delays to the building program by offering all weather installation ability, but further simplifies the building process by eradicating the need for additional base stage inspections and doing away with dewatering as a concern. Adding to this the reduced material cost of helical pile supply over concrete, helical piling can produce savings of up to 20%* over an equivalent bored pier foundation system."
      There are a number of advantages to screw/ helical piling which we discuss in more detail here, (Advantages of screw piling) but Houghton goes on to tell us:
      "When you consider the environmental impact of a project credence is often not given to a well designed and executed foundation system which significantly reduces the wider environmental impact of a project, along with the immediate effects on local ecology. The simple disturbances to the environment brought about by the excavation of 0.5-1CUM of spoil, which is then relocated to either a tipping site, or another area on the subject building site can have massive effects on local flora and fauna. Being that helical piles are a type of displacement pile, there is little to no spoil disturbed during installation." 
      Today, almost any conventional piece of standard excavation equipment, such as a track or wheeled excavator, a mini excavator, a backhoe or a skid steer may be easily fitted with a low-speed, high-torque hydraulic head to provide the required torque for installation. Even in areas of limited access or low head room such as inside the basement of a structure, a small hand-held portable hydraulic torque head and a torque reaction bar can be used to install screw piles inside buildings, providing up to 5,000 nM of torque.

      Digga see the installation of screw piles as a versatile alternative to traditional methods of foundations and as more applications are being found for the use of screw piles they are fast becoming an attractive alternative to traditional cast in place concrete foundations. 

      You can find more advantages of the installation of screw piles here

      For further reading on the evolution of screw piling check out this article which we referenced when putting this post together for you: Civil and structural engineer news article.

      Digga tips - the importance of vertical alignment when drilling.

      Digga machinery attachments
      Having trouble drilling? The correct vertical alignment of your auger into the ground is essential to ensure efficient & effective drilling with your excavator. The natural arc movement of the boom causes the dipper arm to move out of alignment as it is raised or lowered, which is why constant operator adjustments are required to maintain vertical alignment. Please consider, that failure to do so will create significant side load on the auger drive and auger!

      As Digga auger drives are pendulum drills designed to hang freely from the excavator mount - excessive side load may result in bent auger flights, pipe and hubs as well as potential damage to the auger drive shaft, seals and gearbox. When you are drilling especially into hard ground this may also  cause socket and pilot breakage. So make sure to align your auger and drive correctly, to avoid damager and drill which much better performance.

      You can find more info and tips for drilling in harder grounds such as rock or frost here.

      You could also try the Diggalign Inclinometer for greater accuracy.