Patent ID: 12240302

DETAILED DESCRIPTION

Referring toFIG.1for example, there is shown a flutter reducer10protecting a tarpaulin12(seen for example inFIG.2) to eliminate or reduce damages due to fluttering. The flutter reducer10is mounted to a container14that can be selectively covered using the tarpaulin12. Referring toFIG.8, the container14is a vehicle container movable by a vehicle15. For example, the container14is part of a dump truck, or any other suitable vehicle15, is a trailer pulled by a tractor, or is part of a train wagon, among other possibilities. Typically, as seen inFIG.8, the container14defines a container bottom wall17and a container peripheral wall18extending therefrom. Referring toFIG.1, the container peripheral wall18defines a container top aperture20delimited by a peripheral wall top edge16, opposed to the container bottom wall17. The container peripheral wall18defines a wall rear end19. The container peripheral wall18may include a pivoting door at the wall rear end19, or may be permanently closed at the wall rear end19. The wall rear end19is located at a rear of the container14when the container is moved by the vehicle15. The flutter reducer10is however also usable with other structures that may lack the container bottom wall17or part of the container peripheral wall18. The peripheral wall top edge16is in some embodiments in a single plane. In other embodiments, the peripheral wall top edge16is not in a single plane. For example, the front and rear portions thereof are arcuate.

The term “substantially” is used throughout this document to indicate variations in the thus qualifies terms. These variations are variations that do not materially affect the manner in which the invention works and can be due, for example, to uncertainty in manufacturing processes or to small deviations from a nominal value that do not cause significant changes to the invention. These variations are to be interpreted from the point of view of the person skilled in the art. Also, directional terminology such as top and rear, among others, is used in this document and refer to the flutter reducer10and container14in a typical operational configuration. Rear refers to a direction opposed to front, the latter being a direction in which a vehicle15on which the flutter reducer10moves in high speed movements, for example when driving along a highway.

The tarpaulin12is movable between extended and retracted configurations, shown respectively inFIGS.2and1. In the extended configuration, the tarpaulin12extends across the container top aperture20, and in the retracted configuration, the tarpaulin12is withdrawn from at least part of the container top aperture20, typically entirely or almost entirely, to allow access to the container14. The tarpaulin12defines a tarpaulin rear end edge22.

The flutter reducer10is operatively coupled to the tarpaulin12so that when the tarpaulin12is in the extended configuration and the container14is moved by the vehicle15, the flutter reducer10limits movements of the tarpaulin at the tarpaulin rear end edge22to reduce flutter due to relative wind caused by movement through air of the covered container14. The flutter reducer10thus increases the rigidity of the tarpaulin12so that amplitudes of movements due to relative wind buffeting the tarpaulin12is reduced.

Indeed, when extended across the container top aperture20, the tarpaulin12is typically stretched taut thereacross, in a direction lateral relative to the direction of motion of the container14when the latter is pulled. At high speed, the tarpaulin12will tend to flutter at its tarpaulin rear end edge22. The flutter reducer10reduces or eliminate this flutter by supporting part of the tarpaulin12at the tarpaulin rear end edge22.

The tarpaulin12may be permanently mounted to the container14or may be removable therefrom. When permanently mounted, a conventional tarpaulin extension and retraction device (not shown in the drawings) is used to handle the tarpaulin12. The device may be of the type referred to as “lateral”, in which the tarpaulin is rolled around a rod extending along the length of the container14to store the tarpaulin. The rod is typically manipulated using one or two arms provided at the front and/or the rear of the container14. The device may also be of the type referred to as “longitudinal” in which the tarpaulin is mounted to arches extending across the width of the trailer and movable longitudinally therealong. When moved together towards one extremity of the container14, the arches pull the tarpaulin12to free at least part of the container top aperture20. In embodiments in which the tarpaulin12is not permanently mounted to the container14, the tarpaulin is attached typically to both sides of the container14and put under tension using straps. The flutter reducer10is also usable with any other suitable manner of securing the tarpaulin to the container14.

The flutter reducer10takes the form of a support member mounted to the container peripheral wall18at the wall rear end19and reaching above the peripheral wall top edge16on top of a top edge rear portion24of the peripheral wall top edge16. The flutter reducer10may also be mounted to a member extending laterally across the container14at its rear end. The flutter reducer10may have any suitable shape and dimensions and is for example in the form of a support member. An advantageous embodiment of the flutter reducer10includes a blade26and a support28.

The blade26defines a pair of blade mounting portions30and a blade protruding portion32extending therebetween. The blade mounting portions30are each mounted to a respective location on the top edge rear portion24, using for example an adhesive, rivets or bolts, among other possibilities. The blade protruding portion32extends above the top edge rear portion24between the blade mounting portions30.

In some embodiments, the blade26is made of a resiliently deformable polymer sheet. In such embodiments, the blade mounting portions30are mounted to the top edge rear portion, which is for example substantially rectilinear and horizontal, at a distance such that the blade protruding portion32is not stretched flat, but instead protrudes above the top edge rear portion24in an arch to define an apex31. Before mounting, the blade26may be rectilinear, the blade26being deformed to form an arch during the installation process. In other embodiments, the blade26is pre-formed to define the apex31, or a portion thereof that will become the apex31after deformation during installation. The support28, which is omitted in some embodiments, is provided between the blade protruding portion32and the top edge rear portion24, typically at the apex31. The support28is substantially rigid and supports the blade protruding portion32, for example at a location midway between the blade mounting portions30, laterally centered relative to the container14. The support28is secured to at least one of the blade26and the top edge rear portion24. For example, the support28is secured using a nut and bolt combination to the underside of the blade protruding portion32. The blade protruding portion32is in some embodiments substantially smooth laterally relative to the container around its apex, so that no sharp edges are presented to the tarpaulin12across the direction under which tension is applied, which could result in damages to the tarpaulin12. The tarpaulin12abuts against the blade26at the apex31in the tarpaulin extended configuration, in some embodiments slightly above more forwardly located portions of the tarpaulin12. In other words, the apex31is slightly higher than an apex of the tarpaulin12in absence of the blade26.

As seen inFIG.4, if downward external forces are exerted on the blade26in the blade protruding portion32, the latter will be able to deform to reduce the chance that the blade26will be accidentally damaged at locations spaced apart from the support28. However, in other embodiments, the blade protruding portion32is more rigid or less deformable than in the embodiment illustrated in the drawings.

As better seen inFIG.3, once the tarpaulin12has been extended across the container top aperture20and over the flutter reducer10, the tarpaulin12will have its center at the tarpaulin rear end edge22abut against the blade protruding portion32. This will create an increase in tension in the tarpaulin12at the tarpaulin rear end edge22when compared to the tension in front of the tarpaulin rear end edge22, due to the fact that the tarpaulin12extends over a larger distance at the tarpaulin rear end edge22than further in front thereof. This tension will minimize or eliminate upward movements of the tarpaulin rear end edge22, while the blade protruding portion32will minimize or eliminate downward movements of the tarpaulin rear end edge as the tarpaulin12abuts thereagainst. Since upward and downward movements are minimized, flutter will be either reduced or eliminated.

In a specific and non-limiting embodiment of the invention, the blade26is about 15 to 20 cm wide and about 1 to 2 m long. Also, in some embodiments, at least part of the tarpaulin12is vertically spaced apart from the peripheral wall top edge16at the tarpaulin rear end edge22. In such embodiments, if there is no flutter reducer10, large amplitude flutter can lead easily to tarpaulin12damage.

FIGS.5to7illustrate another flutter reducer100usable to reduce or eliminate damages induced by flutter in the tarpaulin12. The flutter reducer100may be used with or without the flutter reducer10, and the latter may be used alone, without the former. The flutter reducer100includes a reinforcement member102mounted to the tarpaulin12at the tarpaulin rear end edge22. The reinforcement member102may be mounted to the tarpaulin12in any suitable manner. For example, as seen inFIG.6, the reinforcement member102is inserted in a pocket104sewn or otherwise secured to the tarpaulin12. However, the reinforcement member102may be riveted or adhered to the tarpaulin12, or otherwise mounted thereto. The reinforcement member102is for example substantially elongated and mounted longitudinally along the tarpaulin12substantially perpendicular to the tarpaulin rear end edge22, midway laterally relative thereto. More than one reinforcement members102may also be provided, laterally and/or longitudinally spaced relative to each other.

The reinforcement member is substantially rigid. For example the reinforcement member102has a flexural modulus at least 10, at least 100, or at least 10 000 time larger than the tarpaulin12. For example, the flexural modulus of the reinforcement member102is at least 10 GPa, or at least 50 GPa. The tarpaulin may have a flexural modulus of 2 GPa or less, for example and non-limitingly. The reinforcement member102extends from the tarpaulin rear end edge22towards the front of the tarpaulin and reinforces the tarpaulin12to reduce the tendency of the central portion of the tarpaulin12to deform towards the bottom of the container14. This will also reduce flutter. The reinforcement member102may be made of a suitable polymer or metal, for example, and have a length of between 1 and 2 meters, among other possibilities. Typically, the reinforcement member only extends along part of a length of the tarpaulin12, for example along about 5 to 15 percent thereof. The reinforcement member takes for example the form of an elongated slat or rod, among other possibilities.

The pocket104may be closed at the tarpaulin rear end edge22, so that the reinforcement member102is permanently integrated to the tarpaulin12. In other embodiments, the pocket104may also be open or reversibly closable at the tarpaulin rear end edge22to that the reinforcement member102may be removed to facilitate storage and handling of the tarpaulin12, or when the tarpaulin12is used across structures that would not provide support for the reinforcement member102.

Generally speaking, the flutter reducer10eliminates or reduces the amplitude of at least some lateral oscillation modes in the tarpaulin12, while the flutter reducer100eliminates or reduces the amplitude of at least some longitudinal oscillation modes in the tarpaulin12, longitudinal being with reference to a front-to-back direction of movement of the vehicle15, and lateral being perpendicular to longitudinal. This will reduce movements of the tarpaulin12at the tarpaulin rear end edge22. Some embodiments of both flutter reducers10and100act by rigidifying the tarpaulin12. Indeed, in absence of the flutter reducers10and100, the boundary condition at the tarpaulin rear end edge22is such that his tarpaulin rear end edge22is free to move, except at the lateral ends thereof. By reducing the amplitude of the lowest frequency modes, flutter induced damages are reduced or eliminated as the forces on the tarpaulin rear end edge22can be maintained at a level at which the tarpaulin12remains intact, or is at least more durable.

Although the present invention has been described hereinabove by way of exemplary embodiments thereof, it will be readily appreciated that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, the scope of the claims should not be limited by the exemplary embodiments, but should be given the broadest interpretation consistent with the description as a whole. The present invention can thus be modified without departing from the spirit and nature of the subject invention as defined in the appended claims.