Abstract:
The present invention is directed to a tensioning and lock device for achieving a sufficient amount of tension throughout a tarp cover. The present invention is particularly well suited for retractable, tarp cover systems used in the trucking industry, but is also useful in other applications and in other fields. The tensioning and lock device comprises a base and an extending mechanism comprising an actuator. The actuator may be of the hydraulic, pneumatic, or mechanical variation and can be either manually or automatically powered. The present tensioning device is lightweight, compact, easy to install and accomplishes its function in a minimal amount of time.

Description:
FIELD 
       [0001]    The present invention relates to tarpaulin cover systems, and in particular to a tensioning and locking device for producing and maintaining a sufficient amount of tension throughout a tarp cover. 
       BACKGROUND 
       [0002]    Tarpaulin cover systems are commonly used to cover cargo being transported by truck, train, ship, and other vehicles. It is often desirable to cover cargo to protect it from the elements. It may also be desirable to shield the cargo from view. 
         [0003]    Cargo that is to be transported may be positioned directly on a vehicle, such as on a truck or trailer bed, or on a rail car. Alternatively, the cargo may first be positioned on a shipping base, such as a shipping or cargo pallet. The shipping base may then be placed on or in the vehicle for transport. The term “base structure” will hereinafter be used to refer to both vehicles and shipping bases. In either instance, it is often desirable to cover the cargo being transported. 
         [0004]    Tarpaulin cover systems are particularly common in the trucking industry. One type of shipping configuration comprises a fully enclosed and rigid cargo area. Most of these cargo areas have one or more doors in the enclosure for loading and unloading the cargo. In particular, many trucks or trailers have an opening at their rear end for this purpose. However, such fully enclosed and permanent cargo areas are not well suited for the loading and unloading of certain types of cargo. For example, very large or very heavy items are most easily loaded onto a vehicle, trailer, or base from the top or the side using a crane, forklift or other lifting device. Therefore such large or heavy items are more easily loaded onto a vehicle, trailer, or base having no sidewalls or no roof. Flatbed trucks and trailers are well adapted to carry such loads. However, as discussed above, it is often desirable to cover the loaded cargo during transport, as well as during storage. Tarpaulin cover systems provide an attractive solution as they can be quickly and easily retracted or removed to expose the entire cargo area during loading. 
         [0005]    Tarpaulin cover systems are known in the art. For example, flexible tarpaulin systems for highway trailers have been disclosed in U.S. Pat. No. 5,152,575 to DeMonte et al., U.S. Pat. No. 5,538,313 to Henning, and U.S. Pat. No. 6,511,117 to Henning. 
         [0006]    Retractable tarpaulin systems can come in a flat-top style, as taught by the two Henning patents, or in a peaked style, as taught by DeMonte. An increasingly common style of flexible cover system comprises a plurality of bows that support a flexible cover. The bows, and thus the cover, are moveable, typically along the length of the base or vehicle, and may be retracted in an accordion-like manner to expose a cargo area. The lower ends of each bow typically comprise sliding means, such as one or more wheels or rollers, which ride in or on a pair of tracks or rails on the base or vehicle. 
         [0007]    It is important that the tarpaulin cover in retractable bow-style cover systems be fully stretched-out when the cover is in the extended position. In other words, it is important that tension be maintained in the tarp cover system. This is particularly significant for cover systems that are exposed to high winds or fast-moving air, such as cover systems positioned on vehicles. Firstly, applying and maintaining tension in the cover reduces the severity of flapping in the cover caused by the passing air or wind. A reduction in flapping reduces the material fatigue in the cover and in the bows, and therefore prolongs the service life of these parts. A reduction in flapping also reduces the amount of noise emitted and provides for a quieter ride. Secondly, a taut cover reduces the aerodynamic drag of the cover system. This likely increases the fuel or energy economy of the vehicle transporting the cover system. For the aforementioned reasons, it is desirable to have a satisfactory and substantially uniform tension in the flexible cover. 
         [0008]    Tensioning devices and systems for sliding systems covers are also known in the art. Many existing systems involve the application of a force to the front-most or rear-most bow in order to fully stretch out the cover. For example, one such system is disclosed in U.S. Pat. No. 6,616,211 to Cramaro, which uses a crank and a lever that are connected to rear-most bow of the moveable tarpaulin framework. The crank is first rotated to move the lever into a catch position, and then counter-rotated to further extend the framework, which in turn stretches-out the cover. 
         [0009]    However, known systems such as the one disclosed by Cramaro suffer from a number of shortcomings. In particular, the tensioning force applied in many existing systems is applied to a front-most or a rear-most bow at the lower ends of the bow. As a result, a satisfactory degree of tension can be applied and maintained in the lower side portions of the cover. However, the resultant tension in the upper side portions and the top portion of the cover will be lower than the tension achieved in the lower side portions. This difference can be at least partially attributed to the flexibility of the parts of the covering system, and in particular of the front-most or rear-most bow. 
         [0010]    Existing tensioning devices and systems suffer from further shortcomings. Many systems are heavy or bulky, or both, and are therefore difficult to install and operate. Some systems are inefficient in that they require a significant amount of physical effort or time to achieve the desired degree of tension in the cover. 
         [0011]    For the foregoing reasons, it can be appreciated that a need exists for a tarp tensioning and locking device that produces a satisfactory amount of tension in the entire cover, including the side portions and top portion of the cover. It is also desirable that the device be compact, lightweight, and easy to use. 
       SUMMARY 
       [0012]    The present disclosure provides a tarp tensioning and locking device that addresses the problems described above. In particular, the present invention is directed to a sliding tarpaulin tensioning and locking device for achieving a sufficient amount of tension throughout a flexible cover and locking the tensioning in that position. The tensioning and lock device of the present invention comprises a base and an extending mechanism comprising an actuator. The actuator may be of the hydraulic, pneumatic, or mechanical variation and can be either manually or automatically powered. The device is lightweight, compact, easy to install and accomplishes its function in a minimal amount of time. Furthermore, the present invention is particularly well suited for retractable, flexible cover systems used in the trucking industry, but is also useful in other applications and in other fields. 
         [0013]    In one aspect, the present disclosure is directed to a tarp tensioning and locking device comprising a base; and an extending mechanism for applying a tensioning force to a tarp, the extending mechanism being pivotally connected to the base, the extending mechanism comprising a bar and an actuator for extending or retracting the bar. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    The present disclosure will be better understood having regard to the drawings in which: 
           [0015]      FIG. 1  is a perspective view of a flatbed trailer comprising a sliding tarp cover system and one embodiment of the cover tensioning device; 
           [0016]      FIG. 1A  is an enlarged view of inset  1 A shown in  FIG. 1 ; 
           [0017]      FIG. 2  is a perspective view of a pair of cover tensioning devices; 
           [0018]      FIG. 3  is a sectional side view of a second embodiment of the cover tensioning device in the tensioned position; and 
           [0019]      FIG. 4  is a sectional side view of a second embodiment of the cover tensioning device in the disengaged position. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    The present tarp tensioning and locking device is described in one embodiment in the following disclosure with reference to the Figures. While this embodiment is described in the context of a sliding cover system installed on a flatbed trailer, the scope of the present disclosure is not intended to be limited to sliding cover systems on flatbed trailers. The present tarp tensioning device can be used in other applications and in other fields, including but not limited to tarp systems installed on other vehicles such as trains and ships, and tarp systems installed on separate shipping bases (i.e. not directly installed on a vehicle). 
         [0021]    To provide a degree of background to the present invention, a known sliding tarp cover system is now described with reference to the Figures. 
         [0022]      FIG. 1  shows a flexible cover system  200  installed on a base structure  300 , in this case a flat bed trailer. This cover system is shown in its extended (i.e. tightened) position. A tarp cover  202  is supported by a plurality of support members, or “bows”, over the trailer bed  300  thereby defining an enclosed cargo area. The sliding tarp system can comprise end bows at the front and rear, such as a rear bow  210 , and can also comprise one or more intermediate bows  230 . The end bows, such as rear bow  210 , may be of a more rigid construction to support the end loads of the tarp  202 . For example, as best shown in  FIG. 1A , the rear bow  210  can comprise a pair of vertical support members  212  joined by braces  214 . The lower ends of each bow are slidably connected to the trailer bed  300  by way of a known wheel system. The slidable connection of the bows to guide members, such as tracks or rails  302 , enables the longitudinal movement of the bows along the length of the trailer  300 . The slidable connection may be formed by connecting one or more wheels  218  to the ends of a bow, each wheel riding in a track  302  positioned along an edge of the trailer  300 . 
         [0023]    When the time comes to expose the cargo area of the trailer, the tarp cover  202  and plurality of bows  210 ,  230  are moved towards one end of the trailer, usually the front end. The tarp cover  202  thereby collapses in an accordion-like manner. When the tarp  202  is to be moved into its extended position, the cover  202  and bows  210 ,  230  are moved towards the opposite end of the trailer  300 , typically the rear end. 
         [0024]    The various features and components of the present cover tensioning and locking device are now described. 
         [0025]    As shown in  FIGS. 1A and 2 , in at least one embodiment, the tensioning and lock device  100  of the present invention comprises an extending mechanism  120  and a base  130 . The device  100  may also comprise a vertical support  110 . It should be noted that  FIG. 2  shows a pair of tensioning and lock devices  100 , which can be used in tandem. 
         [0026]    In at least one embodiment comprising a vertical support, the vertical support  110 , extending mechanism  120 , and base  130  can be arranged in a triangular formation. The lower ends of both the vertical support  110  and the extending mechanism  120  are pivotally connected to the base  130  at spaced apart points on the base  130 . Furthermore, the upper ends of the vertical support  110  and the extending mechanism  120  can be pivotally connected to one another, or to a common connection member, such as an engagement member  112 . 
         [0027]    The tensioning device  100  may be built to restrict the movement of the extending mechanism  120 , as well as a vertical support  110 , to a single plane of motion. This would prevent any unnecessary side-to-side movement of the extending mechanism  120  and vertical support  110 . 
         [0028]    Vertical support  110  can serve as a guide and support for the extending mechanism  120 . In effect, the vertical support  110  directs the force exerted by the extending mechanism  120  in the desired direction to apply tension in the tarp cover  202 . In the embodiment illustrated in the Figures, the desired direction is towards the rear of the trailer and is substantially parallel to the longitudinal axis of the trailer. This direction is indicated by arrow Y in  FIG. 3 . The application of force in this direction will fully extend the cover system  200  and will produce tension in the tarp cover  202 . 
         [0029]    As best illustrated in  FIG. 1A , the tensioning system  100  can comprise an engagement member  112  for engaging the cover system  200 . The engagement member  112  can be connected to or formed integrally with the upper end of the extending mechanism  120 . In at least one embodiment, the engagement member  112  is adapted to engage a bow, such as rear bow  210 . For example, in the embodiment shown in  FIG. 1A , the engagement member  112  can comprise a recess or notch  114  for engaging a mechanical obstruction, such as a pin  220 , on the bow. The pin  220  can comprise a stop member  222  at its distal end to prevent the engagement member  112  from slipping off of the pin  220  when force is applied to the pin  220  by the tensioning device  100 . The engagement member  112  can further comprise securing means to releasably secure it to the cover system  200 , including but not limited to a clip, a clamp, and any other suitable type of fastener. 
         [0030]    The relative height at which the tensioning device  100  applies force to a bow, such as the rear bow  210 , is an important consideration. In particular, the relative height at which the extending member  120  applies the tensioning force to the tarp  202 , or the rear bow  210 , should not be overlooked. It is desirable to obtain a satisfactory and substantially uniform amount of tension in all areas of the tarp cover  202 , which includes lower and upper side portions  204 ,  206  and the top portion  208  (see  FIG. 1 ). One way to achieve a satisfactory and substantially uniform degree of tension in the tarp cover  202  is to position the upper end of the extending mechanism  120  such that it exerts a tensioning force at approximately the vertical midpoint of the tarp cover  202  or rear bow  210 . The embodiment of the tensioning device  100  shown in  FIG. 1  has such a configuration. Such a configuration should provide a satisfactory and substantially uniform amount of tension in the lower and upper side portions  204 ,  206  of the cover as well in the top portion  208 . However, if the extending mechanism  120  engages the cover  202  or rear bow  210  at too low of a height, then the degree of tension in the upper side portions  206  and the top portion  208  of the cover  202  may be inadequate. Likewise, if the extending mechanism  120  engages the cover  202  or rear bow  210  at too high of a height, then the degree of tension in the lower side portions  204  of the cover  202  may be inadequate. 
         [0031]    The extending mechanism  120  comprises a rigid extension member, such as a bar  122 , and also comprises an actuator  124 . The actuator  124  is connected to the bar  122 , and selectively extends and retracts the bar  122  in the directions indicated by arrow X (see  FIG. 1A ). 
         [0032]    The actuator  124  can be powered either manually (e.g. by hand) or automatically (i.e. by another energy source), and should be capable of producing a sufficient amount of force to obtain satisfactory amount of tension in the tarp cover  202 . In addition, it is very important that the actuator  124  be capable of entering a locked state, in which any further extension or retraction of the bar  122  is resisted. When a plurality of tensioning devices  100  are used together, the actuators  124  of each device can be powered individually or collectively. As best shown in  FIG. 2 , in at least one embodiment the actuator  124  is a hydraulic cylinder, which is part of a manually powered hydraulic system  250 . The hydraulic cylinder is fluidly connected to a master cylinder  252  by hydraulic line  254 . The master cylinder  252  can comprise a handle  256  for manual operation. 
         [0033]    As mentioned above,  FIG. 2  shows a pair of tensioning and lock devices, which can be used in tandem to form a single tensioning system. In the embodiment shown in  FIG. 2 , the two tensioning devices  100  are powered by the same hydraulic system  250 . The line exiting the master cylinder  252  splits into two separate lines, each one being fluidly connected to one of the tensioning devices  100 . Alternatively, each tensioning and lock device  100  could have separate means to power its actuator  124 . 
         [0034]    In addition, a person skilled in the art would appreciate that suitable alternatives to a manually operated hydraulic system exist to power the actuator  124 . That is, the actuator  124  can comprise any other suitable means for selectively extending and retracting the extension member or bar  122 . These means include but are not limited to pneumatic devices or systems; mechanical devices or systems including but not limited to worm gear mechanisms, ratchet mechanisms, rack and pinion gear mechanisms; as well as other mechanical, hydraulic, pneumatic and electrical means. 
         [0035]    In addition to supporting the extending mechanism  120 , and in some instances a vertical support  110 , the base  130  can serve as a mounting point for the tensioning and lock device  100 . As shown in  FIG. 1A , in at least one embodiment the base  130  engages a mounting plate  140 , which can be installed on the base structure  300 , such as a trailer or truck bed. The engagement of the base  130  with the mounting plate  140  may be a releasable engagement thereby allowing for quick and easily installation and removal of the tensioning and lock device  100  from the base structure  300 . 
         [0036]    Although the base  130  is depicted in the Figures as an elongate member, it is to be understood that the base  130  can take other shapes and forms, and may be much shorter and or smaller than depicted. This is particularly so where the tensioning device  100  does not comprise a vertical support  110 . In such a configuration, the base  130  does not support a vertical support  110  and therefore need not have an elongate shape. 
         [0037]    The operation of the present cover tensioning device is now described.  FIGS. 3 and 4  show the tensioning device  100  in two different stages of operation.  FIG. 3  shows the tensioning device  100  in the disengaged position, whereas  FIG. 4  shows it in the engaged, or tensioned, position. In  FIG. 3 , the rear bow  210  and thus the tarp cover  202  is not fully extended towards the rear of the base or trailer  300 , and the extending mechanism  120  of the tensioning device  100  is in a retracted state. In operation, the engagement member  112  of the tensioning device  100  is positioned in contact with or in proximity to the pin  220  on the rear bow  210 . The actuator  124  is then activated, thereby extending the bar  122  of the extending mechanism  120 . As the extending mechanism  120  extends, it pivots the upper portion of vertical support  110 , as well as the engagement member  112  connected to the upper end thereof, in the direction indicated by arrow Y. The force of the extending mechanism  120  is applied to the pin  220 , and thus the bow  210 , also in the direction of arrow Y. This force expands the cover  202  in the same direction, in this case towards the end of the base structure or trailer  300 . Once the desired degree of tension in the cover  202  has been achieved, the actuator  124  is deactivated and the cover  202  is held in a tensioned and locked state. To release the tension in the cover  202 , the actuator  124  is selectively activated to retract the bar  122 . 
         [0038]    The present cover tensioning device  100  has herein been described and illustrated as being disposed at the rear end of a base structure or trailer  300 . However, it is to be understood that the tensioning device  100  can be positioned at various other suitable locations relative to a tarp cover system. For example, the device  100  can be installed at the front end of a base structure or trailer. Furthermore, one or more tensioning devices  100  can be positioned at opposite ends (e.g. front and rear) of a base structure or trailer  300 . 
         [0039]    The previous detailed description is provided to enable any person skilled in the art to make or use the present invention. Various modifications to those embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention described herein. Thus, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the full scope consistent with the claims, wherein reference to an element in the singular, such as by use of the article “a” or “an” is not intended to mean “one and only one” unless specifically so stated, but rather “one or more”. All structural and functional equivalents to the elements of the various embodiments described throughout the disclosure that are known or later come to be known to those of ordinary skill in the art are intended to be encompassed by the elements of the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims.