The new generation of Toomey Scrapers have unparalleled performance in High Speed High Accuracy Trimming, Bulk Earthmoving (sticky wet conditions or hard dry conditions), High Slope Drainage Work and many other field and construction applications. The new generation Scrapers also feature higher rated payloads, lower unladen tare mass, and reduced maintenance requirements. To find out more about the improvements of the new generation over the previous generations and how these in combination with the revolutionary features of the original Toomey Scraper make it a world class piece of machinery, read on…
Since the construction of the first Toomey Scraper in 2012 the design of the Toomey scraper has been altered and refined rapidly over the past 4 years to become what is now our current range of scraper graders. In this article we will go through some of the significant changes to the design and their subsequent improvements to the reliability, usability and life of the Toomey scrapers.
Construction Revisions The first generation of Toomey scrapers were manufactured primarily from 350 grade flat plate, 350 grade cold formed sections (RHS & SHS) and hot rolled structural sections (UB & UC). These early construction methods resulted in ease of construction from quite primitive CAD models. It allowed a degree of flexibility for change during the construction phase and were materials that the manufacturing crew were familiar with. The early scrapers were dependent heavily on a trial and error style of design validation with no form of formal engineering calculations or strength checks conducted. Issues began to develop with a lack of consistency in strength across the buckets being produced. Some buckets were showing signs of structural failure and fatigue early in their life where others of the same design and construction methods were not showing any of those signs. These issues were put down to the insistency in the quality of the steel being supplied and was confirmed when, after the dramatic structural failure of one bucket, it was uncovered that the steel manufacture had sourced steel from a non reputable country.
In response to the failures caused by imported material the machines were beefed up by adding thick plates to the box sections in the rear frame to compensate for the reduced strength materials being supplied. These design modifications were considered temporary and new and improved designs had to be developed. This eventually led to the use of pressed steel being fabricated to replace the RHS in the rear frame. The success of this construction method led to it being adopted more widespread across the machine to the point that the only cold formed sections (RHS & SHS) found in the current models is limited to the laser mount frame.
In addition to the reduced usage of cold formed sections, the hot rolled sections used in the front cross member of the scraper were also replaced with circular hollow products with a yield stress far exceeding that of the hot rolled sections. In addition to the higher strength, it removed a significant amount of welding. The strength of the front cross beam was heavily dependent on the strength of these welds and thus removing those welds removed any probability of undetected weld issues and also, in our opinion, created a more aesthetically pleasing design. Secondary benefits of going to a circular member were the fact that the circular shape was less likely to hold dirt and mud and make cleaning easier. The use of circular members was also extended to the ripper bar and also the top member in the rear frame.
Material Revisions After the evolution of the design towards more pressed plates and less structural sections, it became apparent that the design would suit the use of high strength Quenched and Tempered Steels (Q&T). After much research, SSAB was chosen as the preferred supplier and were consulted heavily in the selection of the steel for the scrapers. The components which have to deal with abrasion of the dirt and mud are manufactured using the wear resistant Hardox 450 and those components not working in a ground engaging environment are manufactured using their high strength plate Strenx 700 (Formerly Weldox 700). The welding procedures, consumables and operator training all had to be revisited to suit the new materials. Overall the use of the high strength steels has allowed the tare mass of the scraper to be reduced while increasing the capacity of the scraper. The higher wear resistance of the bowl and apron mean that replating and repairing due to abrasion is not expected to be of concern over the life of the Toomey Scrapers.
Hydraulics The hydraulic functions have remained basically the same since the original ALG4500 however there have been many small modifications to various aspects. Hydraulic cylinders have been an area of hydraulics which has taken some time to get right. The original hydraulic cylinder supplier, although a reputable and known company in the industry, had some major flaws in the design of their cylinders they were providing. In overcoming these problems replacement components were made in house with our CNC equipment. Eventually all cylinders were then made in house, utilising the redesigned components, to guarantee their strength and quality. However, manufacturing hydraulic cylinders consumes a lot of time from the CNC equipment which is typically utilised for other components for the scrapers. After going through all the effort of developing the new hydraulic cylinders, Toomey have partnered with Alford Hydraulics to supply these cylinders to the required specifications as well as providing service and support moving forward.
Another area of hydraulics which has seen considering advancement since the original ALG4500 is the routing of the hydraulic lines. With the changes of the design towards more pressed components, the routing of the solid lines has been improved making both the creation of the lines and the assembly of the lines both easier and quicker.
The design now allows for either complete control of the hydraulic functions by tractor remotes or complete function of the hydraulic functions by Danfoss control of the power beyond circuit. The hydraulic lines are set up so that all that is required to change from one to the other is to move some JIC caps and fit a couple of hoses to the Danfoss valve. Additional Danfoss banks can be added at any stage with very minimal fuss and all the components to do so can be supplied by Toomey Earthmovers. In addition to the simpler routing, all the detail of hydraulics lines, solid zinc tube and rubber hoses are captured in the design and are available in the User Handbook to be ordered as spares or to replaced damaged items making it quicker to get a machine back up and running.
Bowl Operation The combination of the tipping bowl and the ejector is our signature feature. It has remained the same in concept from the original model however some minor refinements have been made to the swing door geometry over the original model with the aim to achieve even better functionality in the extremely sticky materials.
Apron Operation One of the single greatest improvements over the original ALG4500 Apron was the relocation of the apron cylinders. The location of the apron cylinders on the original ALG4500 was in a similar location to other Australian laser buckets which was on the outside of the side wall and connected to the apron via an axle which ran inside a large slot in the sidewall. It was a common complaint from operators of the early Toomey Scrapers, that during trimming operations in nice soft sandy conditions, product would spill out of these slots and leave nice little mounds on the freshly trimmed field. In addressing these complaints, the apron cylinders were brought inboard removing the need for the slots in the side walls.
In addition to this change the shape of the apron was also revised. The original apron design was based loosely on a common Australian laser bucket design. It was discovered that this design of apron compresses the product into the bowl when being closed. This functioned quite well on the machine it was intended for which was not very efficient at loading product into the bowl. On the Toomey scraper, the design of the bowl was efficient which meant there was nowhere to squeeze that last bit of dirt while closing the apron. To rectify this, the shape of the bowl was changed so that the shell of the apron sliced through the product without compressing it into the bowl. This allowed the scraper to close the apron even with the bowl grossly over loaded. The final modification to the design of the bowl was the implementation of the hinged design or “two-piece apron”. The allows half of the bowl to hinge forward and lay flat above the rippers allowing the operator to have a full view of both the cutting edge and also the bowl itself, something that is very important for final grading and brushing work of fields.
Swing-arms & Rockers The overall concept of the swing-arm and rocker design on the Toomey Scrapers has remained similar however there have been some improvements to the design and construction of them. The original concept of the dual cross levelling capability has remained and still produces some of the highest cross slope angles in the industry.
The most noticeable change has been to the width of the rocker plates, the swing-arm structure has been narrowed and the rocker plates have been brought closer together. This brings the inner wheels further outward and increases the stability of the scraper and helps improve its trimming capabilities. The construction of the swing-arm has gone to high strength steels and also utilises un-honed cylinder tube to mount the pivot bosses. The rocker plates have remained thick 350 grade steel plates as the stiffness is more favourable over the use of thinner higher strength steel plates. The very first scrapers had holes drilled and tapped into the rocker plates however these were changed early on to a drilled and counter bored hex profile to house high strength bolts. This made replacing damaged bolts or even upgrading bolt grades an easy task. The early design revisions incorporated a stopper to stop the forward wheel dropping into a hole and causing the rockers to go over centre and end up supporting the weight on the single wheel. Although not happening often, it also became known that operators were able to get the rear wheel to go over centre. To avoid this, the design was revised so that now there are stoppers for both directions. Even though the stoppers prevent this from happening the swing-arm geometry has been revised around the rocker pivot shaft so that it will remain structurally sound even if all the weight was carried by one of the two axles.
Mouldboard Design The early Toomey Scrapers had a mouldboard cutting angle of 45°. From feedback from clients, it was decided that this required too much of the tractors power for loading and this was then changed to an angle of 35°. The new angle has proven to work well and results in ease of loading in a variety of environments as well as maintaining the ability to conduct final trimming operations well. Some clients with older scrapers have modified their mouldboards in accordance with plans issued by Toomey earthmovers and have reported great improvements in the behaviour of the scraper. The original mouldboard was a five piece construction with flat plates welded together to form the ‘V’ shape. The change to the shallower angle meant a change in construction method was possible. A single plate is now pressed to form the ‘V’ requiring close to 1,000 tonnes to press the angle. The strength has increased and the reliance on welds has been reduced.
Cutting Edges The original edges were made from industry standard material and were a 3 bolt adjustment, reversible type pattern. When the mouldboard angle was reduced, there was a need to change the edge design and a new 4 and 5 bolt one way pattern was utilised. The steel in these new edges was also changed to more abrasion resistant Boron-infused steel. This combination has allowed for a much greater percentage of the edge to wear and increased the operating time between changes.
Router Edges The latest generation Toomey Scrapers have included router edges at the front of the sidewalls. These have been included due to some client requests to have the ability to dig straight down into a paddock for bulk soil removal or extracting clay. These are not typically featured on laser buckets however trials have shown that including them has no adverse effect on the trimming or grading capabilities of the machine and have for all practical purposes, increased the grading width. Being seen as only providing positive benefits for the Toomey scrapers they have been included on all models across the range.
Bearings & Bushes The original machines used industry standard hardened steel bushes in the pivots and ag style hydraulic cylinder clevises. As the scraper models were revised, the use of ag style clevises made way to spherical bearing style clevises on the hydraulic cylinders. The typical bucket had more than 40 grease nipples and required daily service. To reduce this amount of daily service time, the machines have recently shifted to a “maintenance free” solution utilising SKF’s fibre-wound PWM bushes and Hallite caged wiper seals to keep contaminants out. The hydraulic cylinders now feature SKF’s TXE-2LS bearings with Teflon lining and integral triple lip seals. The spherical bearings in the rockers and apron pivots are also SKF TXE bearings and their housings feature additional wiper seals and o-rings to keep contamination out. The SKF products have only been in service 9 months but the results look promising. Like any part of the design they will be constantly monitored and assessed to guarantee they are the best solution for the Toomey Scrapers and our clients.
Paired with the SKF products are custom made pins and shafts. These shafts and pins are manufactured from induction hardened, chrome plated and precision ground 38MnVS6 high strength shaft. The shafts are machined and pin flanges welded on. The shafts are then carefully prepared for zinc plating. This manufacturing process results in an ideal shaft tolerance for the both the spherical bearing and bushes, it also results in great corrosion resistance of both the chrome shaft and zinc plating and also means that in future maintenance operations the pin will be easier to remove, again resulting in less down time.
Hydraulic tube and hose routing has now been completely detailed and drawings for these are used to manufacture the hydraulic tubes and hoses before the construction of the machine has even commenced. Each component has its own part number and detailed drawing outlining the processes involved in completing that component with QA checks along the way. All this information is stored on the cloud for easy access by multiple devices. Management or engineering can check the progress of this QA process easily. The system of detailed drafting and checking ensures that when components, fabrications or assemblies are outsourced to boost scraper manufacturing capacity, quality can be maintained and assured. In addition to the advantages to manufacturing, the detailed computer models are used to generate the detailed user handbooks. The information presented in these handbooks greatly benefits the clients and assists them to better understand their asset and what is required to keep it performing at its best. It also means identifying spare parts or replacements parts is much easier.
It’s the rapid development and growth of the Toomey Scrapers, from working with our clients, suppliers and experienced personnel which has brought about unparalleled performance in high speed trimming, bulk earthmoving, high slope drainage construction, performance in both soft and sticky materials as well as hard and try materials. All this is achieved while reducing unladen Tare Mass, increasing reasing capacity and reducing maintenance operations.