HY-TEC Tumbulgum Quarry has recently taken delivery of an Articulated Dump Truck to perform load hauling duties at the quarry. Articulated Dump Trucks (ADTs) are a commonly used piece of equipment in quarries as an alternative to Rigid Dump Trucks. These type of trucks may have an unwarranted reputation for tipping over and in the view of some plant operators they are designed to tip over. This is simply untrue. Any ADT overturn incident, even if does not directly lead to personal injury, will cause unnecessary business disruption, create machinery repair cost and can put others at risk during the recovery operations.
Investigations of ADT overturn events while tipping have identified the following causal factors as being common, either individually or in combination.
• Soft or sticky or un-compacted ground
• Tipping too close to an edge
• Tipping on an excessive gradient or on a cross-fall
A common problem is that normal reaction time can be 2 to 3 seconds too late. We are simply guessing if the angle we are looking at is too great to tip the load and at times have the impossible task of knowing when the load has stuck in one corner and causing the truck to lean one way or another rapidly.....by the time we see its leaning and react it is simply too late. I asked OEM suppliers and haulage companies about a system they new of, which would take the risk decision making process away from the truck operator when tipping to ensure there would be no truck tip overs in their business.
Eventually after exhaustive research I came into contact with a man in Evansville Indiana USA, named Jimmy Wink, who has developed a safe tipping system which ticked every box I had concerns about, called the Wink Anti Tip System. This, I believe is the only system in the world that “automatically" decides what is safe and lowers the body at the moment necessary to save it from tipping over.
HOW DOES IT WORK: This system consists of a Sensor/monitoring device that is set at the factory. It is set, based on what is an appropriate and accepted allowance by the purchaser for the truck to lean when tipping. The lean factor chosen for this truck was 5 degrees.
HOW DOES IT WORK: Some articulating trucks may require two hydraulic valve kits, one on each of the lifting cylinders on the power up side, the Komatsu HM400 only required one as the two return lines interconnect into one return line. A disconnect switch is attached to the body so when the body is down it disconnects the connection between the sensor/monitoring box to isolate the valves. If the sensor is outside of its pre-determined limits, it will not allow the body to raise and alternatively, if the sensor limit is breached while raising the body it will stop raising and immediately start lowering.
HOW DOES IT WORK: The sensor box is connected directly to a warning light that is placed either on the front of the body so the driver can see it in the rear view mirror while reversing or mounted in the cabin.
This light has twopurposes:
1. - To make the process of finding a safe place to dump quick and know when they can safely dump. If the light is on, the body will not raise. The operator can only raise the body when at a point that the light is off.
2. - As the driver is going from point A to point B the light will come on and off when the truck leans back and forth more than the setting allows. This just simply tells the driver that the system is functioning. If the driver doesn't see the light come on during a trip then they should be aware that something is not working and they do not have the protection.
NOT LIKE ANY OTHER: This system is unique because the control box mounts to the body not the axle like other designs. The axle is the last thing to lean. For example, if the body is loaded heavy to one side and you are sitting on a level concrete slab, the body is tipping over before the axle reads its leaning
We implement and install safe operating procedures, reversing alarms, reversing cameras etc, to limit the risk of something going wrong but how these controls impact on the operation of the truck it is still at the discretion of the operator. With the Wink Anti Tip System, it is in control and removes the risk decision process from the operator and gives assurance to the business that, what some may say is the inevitable event of a tip over, should not occur.