DETAIL OF SUPPORT STRUCTURE POSITIONED ONTO SPMT'S
INSTALLATION OF TWO BRIDGE SECTIONS WEIGHING 1200 TON EACH BY MEANS OF SPMT'S
JACKING DOWN OPERATION PERFORMED BY MEANS OF SPMT'S
LOAD OUT DETAIL
PPU AND REMOTE CONTROL DETAIL
SPMT POSITIONING DETAIL
OVERVIEW...Self-propelled modular transporters (SPMTs) are multi-axle trailers designed for the transportation of large and heavy cargoes. The SPMT's are designed in modular construction and can be coupled side to side and end to end, or remote units can be operated as a single transporters via radio controls. OPERATIONAL ADVANTAGES...The SPMT's consist of a very strong and rigid chassis, which also acts as a load-carrying platform to which wheel bogies are attached in pairs to form the required length of transporter. Each wheel bogie consists of two rubber tyred wheels and is rigidly fixed to the chassis by a hinged elbow joint, which is supported on hydraulic rams. This hydraulic ram acts as the suspension for the SPMT and also provides the lifting capability. Attached to the end of the SPMT is a Diesel driven power pack, which provides hydraulic power to the various functions of the SPMT.The SPMT is propelled by hydraulic drive motors, which are mounted on the axles of the SPMT. Hydraulic power is supplied from a pump on the power pack to each of the drive motors and speed is controlled via a remote hand operated portable console. Forward and reverse travel is achieved by reversing the flow of hydraulic oil to the drive motors. Speed of the driven axle is controlled by flow regulators, which prevent over-speed of the wheels occurring. Normal operating speed of the SPMT's is 5 km/hr, but may vary depending on the load and configuration.The steering of the SPMT's offers major advantages over other forms of conventional hydraulic trailers. The steering is controlled by electro-hydraulic motors rather than by a series of mechanical steering rods. Each of the axles of the transporter moves independently and are monitored and controlled by the computerised control system of the transporter. This offers total flexibility of steering options with each wheel bogie able to swing through 260° (+130°). The position of each wheel is controlled electronically through the remote operations console and nine steering programs are available. The electronic steering control can be utilised for a group of two or more SPMT's to ensure that all wheel bogies of all the transporters act together and turn about a single point.A hydraulic cylinder supports each of the wheel bogies. The cylinders on each bogie can be linked hydraulically to the other wheel bogie cylinders to form groups (Diagram 1).This allows free flow of hydraulic fluid between each hydraulic ram allowing the SPMT to negotiate uneven ground, cambers and gradients whilst maintaining equal loading in each hydraulic ram within that group (Diagram 2).To link all hydraulic rams on a single trailer would result in an unstable transporters bed with no control. The SPMT is normally split hydraulically into three separate hydraulic groups (A three-point suspension) that can be controlled individually from the main power unit (Diagram 3).As the SPMT negotiates uneven ground, cambers or gradients the hydraulic fluid will free flow within each suspension to maintain equal loading within each suspension group (Diagram 4).Addition hydraulic fluid can be can be pumped from the Power Unit (PPU) into or out of each cylinder group to adjust the level of the SPMT.Systematic and controlled pumping of hydraulic fluid into or out of each suspension can raise or lower the transporter bed +300mm from the normal running height of 1500mm. (Diagram 5)Control of the elevation of the transporter is through the hand operated remote console. Safety valves protect the hydraulic circuit so that the transporter platform does not collapse in the unlikely event of hydraulic failure. The SPMT's are equipped with an electro-hydraulic braking system with hydraulically activated spring loaded brake cylinders installed in the wheel hubs. The brakes are controlled through the hand operated remote console. Hydraulic pressure supplied to the brake cylinders pre-loads the brakes and any reduction in this hydraulic pressure will activate the brakes via a mechanical spring; the braking force that results is in proportion to the reduction in hydraulic pressure. In the event of failure of the diesel power pack, hydraulic pump, electronic control system, or other controlling equipment causing a loss in hydraulic pressure, the brakes will be applied automatically through the spring mechanism.The load carrying capacity of a transporter platform (or group of platforms) is directly proportional to the number of axle line. The capacity of each axle line is 36te gross and 32te net.A transporter convoy, composed of transporter units and power packs can be controlled by a single operator by means of the hand operated remote console. All units are both CE and TUV certified and are provided with identification plates that allow them to be driven on public roads.