AU753221B2 - Tarpaulin securing apparatus - Google Patents

Description

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AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

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Name of Applicant/s: Actual Inventor/s: Address for Service: Invention Title: David Ross Adams David Ross Adams BALDWIN SHELSTON WATERS 60 MARGARET STREET SYDNEY NSW 2000 'TARPAULIN SECURING APPARATUS' Details of Associated Provisional Application No. PP7264 dated 24 NOV 1998 The following statement is a full description of this invention, including the best method of performing it known to me/us:- File: 25907AUP01 la TARPAULIN SECURING APPARATUS This invention relates to a tarpaulin securing apparatus and has been devised particularly though not solely for securing covering tarpaulins over large open topped bins typically used on trucks for the transport of grain and other particulate materials.

It is common to transport grain and other particulate materials in bulk by way of large trucks incorporating rectangular open topped bins typically loaded through the top of the bin.

In order to protect the contents of the bin from weather damage, contamination and loss of load due to airflow over the bin induced by movement of the truck, it is normal to provide a removable tarpaulin which is fastened in place over the top of the bin once oo .*loading has been completed.

In the past it was common to secure such tarpaulins by way of tie downs in the form of a series of ropes or rubber rings around the perimeter of the tarpaulin but this method has fallen from favour due to the hazard imposed on an operator, climbing to the top of the bin to secure the ropes or rubber rings. It is therefore become known to use a 'side rolling' tarpaulin system whereby the tarpaulin is secured along one side of the bin and provided with a roller which extends the length of the bin and is rotatable by an operator, typically from the back of the truck, to roll the tarpaulin across the top of the bin or retract the tarpaulin when loading is required.

The presently used tarpaulin roller system has the disadvantage that any forward motion of the bin creates an airflow effect which lifts the end of the tarpaulin sufficiently to allow the entry of water or debris and furthermore during winding or unwinding of the -2tarpaulin, a gust of wind can lift the tarpaulin and roller from the top of the bin and blow it onto the ground.

Furthermore, it is common to provide bins of this nature with end edges which are peaked at or about their midpoints to provide for water run off from a deployed tarpaulin, with the resulting necessity to wind the tarpaulin 'up hill' during deployment over the first half of the bin. This movement can result in slippage particularly when the tarpaulin is wet, making it difficult to roll the tarpaulin into place across the top of the bin.

o o* Accordingly, the present invention provides a tarpaulin securing apparatus for an open topped bin of the type having an upper rim with parallel side and end edges, wherein the bin is adapted to be covered by a rectangular tarpaulin fastened at one edge to a first side edge of the bin and rolled upon a roller extending the length of the bin with the ends of the roller resting upon respective end edges of the bin, such that the roller can be unrolled across the bin to deploy the tarpaulin, said apparatus comprising a pair of elongate sealing bars located one above each end edge of the bin adapted to sandwich the end edges of the tarpaulin between the end edges of the bin and the sealing bars, and control means connected between the sealing bars and the bin adapted to locate the sealing bars during rolling and unrolling of the tarpaulin.

Preferably the sealing bars incorporate guide means for each end of the roller, adapted to locate the roller during rolling and unrolling of the tarpaulin.

-3- Preferably the guide means comprise elongate slots or channels extending along the sealing bars and the roller includes end portions engageable with the respective slots or channels.

Preferably clamping means are provided, adapted to clamp the sealing bars down onto the end edges of the deployed tarpaulin.

Preferably the second side edge of the bin, opposite the first side edge, is provided with an outwardly extending ledge arranged to restrain the roller from upward or inward movement when the tarpaulin is deployed and the clamping means includes the interaction of the roller restrained under the ledge with the slots or channels in the 10 sealing bars.

Preferably the clamping means includes a pair of tensioning devices operable between the ends of the sealing bars adjacent the first side edge of the bin, and the bin.

Preferably each tensioning device comprises a pneumatic piston and cylinder assembly operable to apply a downward force to the adjacent sealing bar by way of a lever arm linkage.

Preferably the pneumatic piston and cylinder assemblies are actuated by a pressure switch to release the downward force, triggered by upward movement of the sealing bars caused by rolling the tarpaulin onto the roller.

Preferably the control means comprise rods or bars extending downwardly from the sealing bars, slidably located in collars mounted on the bin arranged to permit vertical movement of the sealing bars while locating the sealing bars above the end edges of the bin.

Preferably the end edges of the bin are peaked at or about their midpoints to provide for water run off from the deployed tarpaulin, and the roller is provided with tensioning means arranged to urge the roller toward and over the peak during deployment.

Preferably the tensioning means comprise an elastic tendon extending from a suitable anchor point, around a pulley located at the second side edge end of the sealing bar, to the roller.

Preferably the bin is located on a vehicle and the securing apparatus is arranged to restrain lifting of the tarpaulin from the edges of the bin due to air flow resulting from 10 movement of the vehicle.

Notwithstanding any other forms that may fall within its scope, one preferred form of the invention will now be described, by way of example only, with reference to the :accompanying drawings in which: Figure 1 is a rear perspective view of a truck having a bin incorporating tarpaulin 15 securing apparatus according to the invention; Figure 2 is a rear perspective view to an enlarged scale of the tarpaulin securing °o S apparatus at the rear end of the bin; Figure 3 is a similar view to figure 1 showing the tarpaulin being rolled back from the top of the bin; Figure 4 is similar view to figure 2 showing the tarpaulin in the position of figure 3; Figure 5 is a similar view to figure 4 showing the tarpaulin almost completely rolled back from the bin; Figure 6 is a scrap perspective view of the rear left hand side of the bin showing the tensioning device engaged to clamp the tarpaulin securing apparatus in place; and Figure 7 is a perspective view similar to figure 6 showing the tensioning device released with the tarpaulin almost completely rolled back from the top of the bin.

In the preferred form of the invention a tarpaulin securing apparatus will be described for use on a rectangular open top bin forming the load area of an articulated truck or semi trailer but it will be appreciated that the apparatus can equally be applied to any other form of rectangular open topped bin, for example, bulk field storage bins used :on farms.

10 In the preferred form of the invention, the bin 1 is mounted on a truck or semi trailer unit 2 and has parallel sides 3 and ends 4. The bin has an upper rim with parallel side edges 5 and end edges 6. The end edges 6 are typically peaked at peaks 7 to provide for water run off from a deployed tarpaulin 8 which is extended across the open top of the bin 1.

15 The tarpaulin 8 is secured in place along one side edge of the bin (the left hand side of the truck as shown in the accompanying drawings) at 9 (figure 6) and is wound onto a roller 10 which extends the length of the bin with the ends 11 of the roller resting on the end edges 6.

The roller is typically provided with a drive axle 12 which extends from the rear end of the roller and is rotatable by drive means which may be in any convenient form such as an electric motor but which typically comprises a universal joint 13 coupled in turn to a long shaft crank handle 14 rotatable by an operator 15 as shown in figure 3.

-6- When the tarpaulin has been deployed across the top of the bin as shown in figure 1, the crank handle 14 may be neatly secured in place as shown at 16.

The bin is further provided with an outwardly extending ledge 17 (figure 4) extending along the side edge 5. When the roller 10 is rotated to a position above side edge 5 during deployment of the tarpaulin, the roller may be further rotated to move over the outer edge of ledge 17 and engaged under the ledge 17 where the tarpaulin may be tensioned by the rotation of the roller to secure the roller in place beneath the ledge 17.

In this manner, both side edges of the tarpaulin are secured in place to the side edges 5 of the bin, but without the tarpaulin securing apparatus according to the invention, remain vulnerable to be lifted by wind pressure at the end edges 6.

The apparatus is therefore provided with a pair of elongate sealing bars 18 located above the end edges 6 at the front and rear of the bin. The rear sealing bar will be described in more detail below and it will be appreciated that the front sealing bar is similar in construction without having to incorporate a through slot for accommodation of the roller drive axle 12.

Each sealing bar comprises a typically flat surface flange 19 which, in use, clamps down on top of the end edges of the deployed tarpaulin, sandwiching the end edges of the tarpaulin between the end edges 6 of the bin and the flanges 19.

The sealing bars are located by control means in the form of rods or bars extending downwardly from each end of the sealing bars, slidably located in collars 21 mounted on the bin 1 and arranged to permit vertical movement of the sealing bars while locating the sealing bars above the end edges 6 of the bin.

The collars 21 may be typically pivotally mounted to the bin by way of pivot pins 22 to accommodate some tilting of the sealing bars during unrolling of the tarpaulin as will be described further below. This tilting is at a minimum on the left hand side of the truck and it is possible for the left hand side collars 21 to be rigidly fixed to the bin in the position shown at 23 rather than pivotally mounted as shown in the drawings.

Each sealing bar 18 incorporates guide means for each end of the roller 10 in the form of elongate slots or channels 24 extending along the sealing bars. The roller includes end portions engageable in the respective slots or channels 24 to locate and restrain the roller and prevent inadvertent lifting of the roller during deployment of the *10 tarpaulin eg, from the effect of wind gusts.

The sealing bar at the front end of the bin may incorporate a channel section with the slot or channel 24 in its rearward facing surface only, whereas the slot or channel in the rear sealing bar 18 must extend right through the bar to accommodate the drive mechanism for the roller.

15 In use, when it is required to retract the tarpaulin from the top of the bin, the drive mechanism is engaged from the position shown in figure 1 and rotated to roll the roller outwardly and upwardly around the ledge 17 until the roller is on top of the right hand side edge 5. This movement causes the ends of the roller to press upwardly against the flanges 19 on the sealing bars 18 and lift the right hand ends of the sealing bars upwardly as can be seen in figures 3 and 4. The tarpaulin can then be progressively wound onto the roller 10 through the position shown in figures 3 and 4 lifting the sealing bars higher as the thickness of tarpaulin builds on the roller 10. Eventually, the roller reaches a fully retracted position slightly beyond that shown in figure -8- When it is required to deploy the tarpaulin, typically after loading the bin, the roller is rotated in the opposite direction, causing the roller to roll up the incline of the end edges 6, over the peaks 7 and down to the other side where it is again engaged under the ledge 17. Once the roller is engaged under the ledge 17, the flanges 19 of the sealing bars 18 sit down on top of the end edges of the tarpaulin, effectively sandwiching the end edges between the flanges 19 and the end edges 6 of the bin and securing the tarpaulin in place.

In many applications, the apparatus as described above is sufficient to secure the oO*o tarpaulin, particularly when used in static situations such as for farmer's field feed bins.

It will be appreciated that the right hand ends of the sealing bars (in the sense shown in the accompanying drawings on the truck illustrated) are held firmly downwardly on top of the tarpaulin by the clamping action from the interaction of the roller restrained under the ledge 17 and the engagement of the ends of that roller in the slots or channels 24 in the sealing bars. In a high load situation, typically on a truck travelling at high speed, it 15 is possible for wind to lift the left hand ends of the sealing bars 18 and it is therefore desirable to provide tensioning devices to securely hold down at least the left hand ends of the sealing bars in this situation.

Accordingly, the tarpaulin securing apparatus may include clamping means in the form of double acting pneumatic piston and cylinder assemblies 25 (figures 6 and 7) located at the front and rear of the left hand side of the bin and operable through bell crank levers 26 rotatable about pins 27 protruding from the side of the bin to engage with saddles 28 depending downwardly from the left hand ends of the sealing bars 18.

-9- When the tarpaulin has been deployed as shown in figure 6, the pneumatic piston and cylinder assemblies 25 may be actuated to move the distal end of the bell crank lever 26 downwardly, engaging the lever with the saddle 28 and firmly clamping the left hand end of the sealing bar in the lower position as shown in figure 6.

This process may be automated for release during unrolling of the tarpaulin by using a pressure switch 29 (figure 4) which is triggered by upward movement of the sealing bar in approximately the position shown in figure 4 caused by winding of the tarpaulin onto the roller 10. Once triggered, the pressure switch 29 operates the double acting piston and cylinder assemblies 25, causing the bell crank lever 26 to move to the position shown in figure 7, releasing the saddles 28 and allowing upward movement of the left hand ends of the sealing bars to permit full unwinding of the tarpaulin to the position shown in figure 7.

Although the clamping means have been described as pneumatic piston and cylinder tensioning devices, other forms of tensioning device can be used such as cables 15 extending downwardly from the ends of the sealing bars, tensioned by 'over centre' or highfield levers located on the sides of the bin.

In some situations, it has been found difficult to roll the tarpaulin (particularly when wet) up the incline of the end edges 6 and over the peaks 7 due to slippage between the tarpaulin and the end edges 6. This problem can be overcome by providing tensioning means arranged to urge the roller toward and over the peaks 7 during deployment. The tensioning means preferably comprises an elastic tendon or bungee cord 30 extending from a suitable anchor point 31 around pulleys including a pulley 32 located at the second side edge of the sealing bar 18 and back to the roller at 33. The end of the bungee cord is typically fastened to the roller by being secured to a ring rotatably engaged with the shaft of the roller.

Although the bungee cord can be anchored in any convenient location, it has been found desirable to lead the bungee cord over further rollers 34 and 35 at the peak and opposite end of the sealing bar respectively and to provide various different fastening points 36 for the anchor point 31 to enable selective tensioning of the bungee cord.

In use, the bungee cord provides a biasing force to the roller 10, urging the roller up the slope of the end edges 6 and over the peaks 7, overcoming any problems due to slipping. It is of course an easy matter to retract the tarpaulin by winding onto the roller 10 10 as the tension in the tarpaulin is easily able to overcome the tension in the bungee cord In this manner a tarpaulin securing apparatus is provided which not only enables the ends of a side rolling tarpaulin to be effectively sealing against wind lifting and the entry of water or debris, but also keeps the roller and tarpaulin in a secure location during rolling or unrolling preventing a gust of wind from blowing the tarpaulin and roller onto the ground which is otherwise a possibility whenever the roller is unlocked from under the ledge on the side of the bin. Furthermore, the use of the bungee cord tensioner overcomes the problem of roller slip, particularly in wet conditions, when the tarpaulin is being deployed.

Claims (13)

1. Tarpaulin securing apparatus for an open topped bin of the type having an upper rim with parallel side and end edges, wherein the bin is adapted to be covered by a rectangular tarpaulin fastened at one edge to a first side edge of the bin and rolled upon a roller extending the length of the bin with the ends of the roller resting upon respective end edges of the bin, such that the roller can be unrolled across the bin to deploy the tarpaulin, said apparatus comprising a pair of elongate sealing bars located one above each 1 end edge of the bin adapted to sandwich the end edges of the tarpaulin between the end 10 edges of the bin and the sealing bars, and control means connected between the sealing #*oo bars and the bin adapted to locate the sealing bars during rolling and unrolling of the tarpaulin.

Tarpaulin securing apparatus as claimed in claim 1 wherein the sealing bars incorporate guide means for each end of the roller, adapted to locate the roller during rolling and unrolling of the tarpaulin.

3. Tarpaulin securing apparatus as claimed in claim 2 wherein the guide means •4S comprise elongate slots or channels extending along the sealing bars and the roller includes end portions engageable in the respective slots or channels.

4. Tarpaulin securing apparatus as claimed in any one of the preceding claims wherein clamping means are provided, adapted to clamp the sealing bars down onto the end edges of the deployed tarpaulin.

Tarpaulin securing apparatus as claimed in claim 4 when dependent upon claim 3 wherein the second side edge of the bin, opposite the first side edge, is provided with an -12- outwardly extending ledge arranged to restrain the roller from upward or inward movement when the tarpaulin is deployed and wherein the clamping means includes the interaction of the roller restrained under the ledge with the slots or channels in the sealing bars.

6. Tarpaulin securing apparatus as claimed in claim 5 wherein the clamping means includes a pair of tensioning devices operable between the ends of the sealing bars adjacent the first side edge of the bin, and the bin.

7. Tarpaulin securing apparatus as claimed in claim 6 wherein each tensioning device comprises a pneumatic piston and cylinder assembly operable to apply a downward force to the adjacent sealing bar by way of a lever arm linkage.

8. Tarpaulin securing apparatus as claimed in claim 7 wherein the pneumatic piston and cylinder assemblies are actuated by a pressure switch to release the downward force, S"triggered by upward movement of the sealing bars caused by rolling the tarpaulin onto the roller. 15

9. Tarpaulin securing apparatus as claimed in any one of the preceding claims •wherein the control means comprise rods or bars extending downwardly from the sealing bars, slidably located in collars mounted on the bin arranged to permit vertical movement of the sealing bars while locating the sealing bars above the end edges of the bin.

10. Tarpaulin securing apparatus as claimed in any one of the preceding claims wherein the end edges of the bin are peaked at or about their midpoints to provide for water run off from the deployed tarpaulin, and wherein the roller is provided with 13 tensioning means arranged to urge the roller toward and over the peak during deployment.

11. Tarpaulin securing apparatus as claimed in claim 10 wherein the tensioning means comprise an elastic tendon extending from a suitable anchor point, around a pulley located at the second side edge end of the sealing bar, to the roller.

12. Tarpaulin securing apparatus as claimed in any one of the preceding claims wherein the bin is located on a vehicle and the securing apparatus is arranged to restrain lifting of the tarpaulin from the edges of the bin due to air flow resulting from movement .g .of the vehicle. 10

13. Tarpaulin securing apparatus when constructed, arranged and operable 9. substantially as described herein with reference to the accompanying drawings. DATED this 24th Day of November, 1999 DAVID ROSS ADAMS Attorney: JOHN D. FORSTER 15 Fellow Institute of Patent and Trade Mark Attorneys of Australia of BALDWIN SHELSTON WATERS 09 9 o,