Field of the Invention

[0001 ] This invention relates generally to a truck load restraint tensioning system. Background of the Invention

[0002] Truck loads are currently tied down using a variety of tie down systems, including those using manually operated ratchets. However, these systems are problematic in that adequate tension may not be achieved or that tension may become loose during transportation. Furthermore, low temperatures and/or dust and/or ice accretion may adversely impact the load holding surface friction coefficient.

[0003] The present invention seeks to provide a load restraint tensioning system, which will overcome or substantially ameliorate at least some of the deficiencies of the prior art, or to at least provide an alternative.

[0004] It is to be understood that, if any prior art information is referred to herein, such reference does not constitute an admission that the information forms part of the common general knowledge in the art, in Australia or any other country.

Summary of the Disclosure

[0005] There is provided herein a load restraint tensioning system comprising a base having at least one bolster defining a load bearing surface and a tensioning mechanism which tensions tensioning members from either side of the bolster in use. [0006] In a preferred embodiment, the system employs hydraulic tensioning with automatic tension control, thereby conferring constant load restraint.

[0007] The tensioning system may be specifically suited for transporting concrete segments as shown in Figure 1 and may achieve low contact pressure on the concrete.

[0008] In embodiments, the present system is easily serviceable and installable wherein the base may be easily twist locked onto a trailer dog. The system may use standard hydraulic cylinders with standard cylinder design with clevis ends (1 ½”Pins). [0009] The base may comprise a pair of bolsters acting on a quadrant of tensioning members. Each tensioning member may be tensioned by the hydraulic cylinder to over 8000 kgf, thereby providing a combined tension in excess of 35,000 kgf which allows for icy and cold (i.e. -20°C) operating conditions.

[0010] The hydraulic cylinders may compactly locate inside the bolsters which and may be accessible for servicing. The hydraulic cylinders may float laterally within each bolster to evenly share tension across the tensioning members. A hydraulic control valve of the hydraulic cylinder may accessibly extend through an elongate channel through a side of the bolster.

[0011 ] The tensioning members preferably employs straps which minimises contact pressure, conforms to the load shape and allows for simple connections.

[0012] The bolsters may comprise maintenance free bearings to reduce friction on the straps which may form cotton real roller profiles to correctly align the member straps. [0013] The system may further comprise an upper frame which may support protective corner blocks to protect the load and keep contact pressure below 18 MPa. Isolators may allow relative movement of the protective corner blocks to prevent bending of the frame.

[0014] The corner blocks may comprise pivotally coupled bearing members. The bearing members of one of the corner blocks may be connected by a double pivot plate to allow the corner blocks to match the edges of the load on an opposite end and the bearing members of the opposite corner block may comprise a single pivot which acts as a stopper to centre the frame on the load. Bungees may return the straps of the upper frame to a centre position.

[0015] The upper frame may define large forklift pockets for easily lifting the frame with a forklift.

[0016] The hydraulic cylinders may draw hydraulic pressure from the prime mover hydraulic system trailer supply. The cylinders may be fitted with a pilot operated check valve. A solenoid operated valve may interface each cylinder. Pushbuttons may operate the solenoid operated valve to tension and release cylinders during loading and unloading. [0017] The system may be configured in an automatic tension fail safe mode comprising pressure sensing and auto tensioning and loss of pressure audio and/or visual alarms. The system may have a park breaker lockout so that the vehicle cannot be moved unless adequate tension is achieved.

[0018] Other aspects of the invention are also disclosed.

Brief Description of the Drawings

[0019] Notwithstanding any other forms which may fall within the scope of the present invention, preferred embodiments of the disclosure will now be described, by way of example only, with reference to the accompanying drawings in which:

[0020] Figure 1 shows a truck trailer dog having a load restraint tensioning system installed thereon;

[0021 ] Figure 2 shows an underside perspective view of a bolster of a base of the load restraint tensioning system in accordance with an embodiment;

[0022] Figure 3 shows a perspective view of the load restraint tensioning system of Figure 1 ; and

[0023] Figure 4 shows a hydraulic circuit of the system in accordance with an embodiment.

Description of Embodiments

[0024] Figure 1 shows a truck trailer dog 127 comprising a load restraint tensioning system 100 securing a load 119. A load 1 19 may comprise a plurality of concrete segments 101 and intervening bunting 128.

[0025] With reference to Figure 3, the system 100 comprises a base 102 having at least one bolster 103 having a tensioning mechanism which tensions tensioning members 104. Whereas the tensioning members 104 may comprise chains and/or cables, in a preferred embodiment, the tensioning members 104 comprise straps 105. The straps may be made from Spanset™ MaXafe™ webbing.

[0026] In the embodiment shown, the base 102 comprises a pair of spaced apart bolsters 103. The bolsters 103 may be held apart by horizontal bracing 108. As is shown in Figure 1 , the bolsters 103 may lie directly across the trailer dog chassis. Undersurfaces of the bolsters 103 may have chassis connectors used to connect the base 102 to the trailer dog chassis.

[0027] Each bolster 103 defines an upper load bearing surface 107. The load bearing surface 107 may comprise a removable steel plate which may be bolted atop the bolster 103. The load bearing surface 107 may comprise a friction enhancing coating such as SpanSet™ Secugrip™ which was found to provide a coefficient of friction of 0.25 at minus 20°C when the system was tension to a combined tension of approximately 35,000 kgf.

[0028] The load bearing surfaces 107 may be inclined towards each other such as at approximately 10° to conform to the arc curvature of the concrete segments 101. [0029] In the embodiment shown, the dual bolsters 103 tension a quadrant of tensioning members 104 for each load. Each tensioning member 104 may be tensioned to approximately 8825 kgf by the tensioning mechanism.

[0030] With reference to Figure 2, the tensioning mechanism preferably comprises a hydraulic cylinder 106. The hydraulic cylinder 106 may draw hydraulic pressure from the prime mover hydraulic system. In this regard, the system 1 00 comprises a plurality of hydraulic hose couplings the couple to the prime mover hydraulic system.

[0031 ] The hydraulic cylinder 106 may float with respect to the bolster 103 so that the tensioning members 104 are evenly tensioned either side of the bolster 102.

[0032] Each bolster 103 may be hollow and the hydraulic cylinder 106 may fit longitudinally therein.

[0033] Either end of the hydraulic cylinder 106 may be restrained by rails 109 aligned along and elongate axis of the hydraulic cylinder 106.

[0034] With reference to Figure 3, a hydraulic control valve 1 10 of the cylinder 106 may extend through an elongate aperture 1 11 through a side of the bolster 103. Flexible hydraulic hoses may couple the hydraulic control valve 110 to allow the hydraulic cylinder 106 to move laterally with respect to the bolster 103.

[0035] With further reference to Figure 2, each tensioning strap 105 may be doubled back at either end of the hydraulic cylinder 106. As shown in Figure 2, either end of the hydraulic cylinder 106 may comprise a rounded pin 1 12 or bearing around which the strap 105 is doubled back. The strap 105 may comprise a connection hook 1 13 at either end thereof. As shown in Figure 3, the hook 1 13 may be used to connect an eyelet 114 of a fixed tensioning member 1 15.

[0036] With reference to Figure 3, each side of the bolster 103 may comprise a roller bearing 1 16. The roller bearing 1 16 may comprise a cotton real profile to space apart the straps 105. The roller bearing 116 may be opposed by a nylon roller strap retainer 1 17.

[0037] In a preferred embodiment, the system 100 comprises an upper frame 1 18 which, in the manner shown in Figure 1 may lie across the load 1 19 in use and which connects to the tensioning members 104. In this regard, the upper frame 118 may comprise fixed tensioning members 115 for each tensioning member 104.

[0038] The fixed tensioning members 115 may similarly comprise straps 105 and may further similarly comprise a pair of adjacent straps 115 for each of the pair of adjacent straps 105 of the tensioned tensioning member 104.

[0039] In use, the upper frame 1 18 is placed across the load 1 19 with the fixed tensioning members 115 hanging down either side thereof. The tensioned tensioning members 104 would then be connected thereto using the connection hooks 113 and tensioned to tie the load 1 19 atop the bolsters 103.

[0040] Each strap 105 of the fixed tensioning members 115 preferably runs continuously across either side of the load. The straps 105 may run through protective corner blocks 120 which interface corners of the load 1 19. Each corner block 120 may comprise pivotally coupled first and second bearing members 121. For one of the corner blocks 120, the bearing members 121 may be doubly pivoted together using a double pivot plate to allow the corner blocks 120 to match the width of the concrete segments 101. For an opposite corner block 120, the bearing members 120 may be pivoted together using a single pivot plate.

[0041 ] Isolators 122 may allow relative movement of the corner blocks 120 to prevent bending of the frame 118. The isolators 120 may comprise rubber pieces.

[0042] The straps 105 may run through the corner blocks 120 and bungee cords 123 may return the straps 105 to a central position. [0043] The frame 1 18 may define two forklift tine channels 124 into which respective forklift tines may be inserted in use to lift the frame 1 18. Each channel 124 may define an entrance 125 and an opposite side may be blocked. Horizontal bracing 126 may hold the channels 124 apart.

[0044] With reference to Figure 4, the hydraulic cylinders 106 may draw hydraulic pressure from the prime mover hydraulic system trailer supply 129. The cylinders 106 may be fitted with a pilot operated check valve 130. The pilot operated check valve 130 may be closed once the system 100 is loaded to maintain pressure within the hydraulic cylinders 106.

[0045] A solenoid operated valve 110 may interface each cylinder. Pushbuttons of a user controller control pendant 131 may operate the solenoid operated valve 110 to tension and release the cylinders 106 during loading and unloading.

[0046] The system 100 may be configured in an automatic tension fail safe mode wherein the system 100 comprises a pressure sensing and auto tensioning controller 132.

[0047] The controller 132 may comprise a processor for processing digital data. The controller 132 may further comprise a memory device in operable communication with the processor via a system bus. The memory device is configured for storing computer program code instructions and associated data. The associated data may comprise a pressure setpoint. In use, the processor fetches the computer program code instructions and associated data from the memory device for implementation of the functionality described herein.

[0048] The controller 132 may operably interface pressure sensors 133 which monitor pressure of the cylinders 106. If measured pressure falls beneath a threshold, the controller 132 may operate the valve 110 to re-pressurise the cylinder.

[0049] The system 100 may further comprise loss of pressure audio and/or visual alarm 133. For example, if the controller 132 is unable to re-pressurise the cylinder 106 to a pressure setpoint, the controller 132 may activate the alarm 132.

[0050] The system 100 may have a park brake lockout so that the vehicle cannot be moved unless adequate tension is achieved. Specifically, the controller 132 may operably interface the park brake lockout and operate the park brake lockout if detecting that pressure within the hydraulic cylinders 106 beneath a threshold using their respective pressure sensors 133. The controller 132 may be configured to only operate the park brake lockout when the truck is stationary.

[0051] The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the invention. However, it will be apparent to one skilled in the art that specific details are not required in order to practise the invention. Thus, the foregoing descriptions of specific embodiments of the invention are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed as obviously many modifications and variations are possible in view of the above teachings. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the following claims and their equivalents define the scope of the invention.