Cam buckle

A buckle for fastening a load strap, comprising a buckle frame, a crossbar extending between side arms of the frame, and a pivotable cam arranged between the side arms. The crossbar forms part of a locking element, which is displaceable between a closed position, in which the crossbar extends between the side arms, and an open position, in which the crossbar is separated from at least one of the side arms, such that a load strap is laterally insertable between the cam and the crossbar.The displaceable locking element may provide great ease of access for laterally inserting a load strap. The integrity of the buckle frame is maintained, increasing the stiffness of the buckle and its ability to withstand tension from a load strap.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to European Patent Application No. 20200525.2, filed Oct. 7, 2020, the content of which is hereby incorporated by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to the field of cam buckles for fastening load straps.

BACKGROUND

Cam buckles are commonly used for fastening load straps when securing cargo or equipment. Typically, one end of the strap is coupled to the buckle, the strap placed around the cargo, and the free end of the strap threaded into the buckle. Pulling the excess strap through the buckle provides the necessary tension to secure the cargo. The cam locks the strap in place, preventing it from slipping back through the buckle, thus keeping the cargo secured.

Threading the free end of the strap into the buckle can be difficult and requires some dexterity. For example, the end of the strap may be frayed, making it difficult to thread into the buckle without causing further damage. Depending on the dimensions of the strap and buckle, the operation can be very difficult to perform while wearing gloves. Pulling the excess strap through the buckle is also time consuming. In particular, if the cargo to be secured is small, the length of strap that needs to be pulled through the buckle in order to achieve the necessary tension can be significant.

WO 2014/154947 A1 and WO 2016/064272 A1 disclose buckles allowing a strap to be inserted laterally, by way of an opening or slot in a sidewall or arm of the buckle frame, thus eliminating the need to thread the strap into the buckle. The opening mechanisms can however be difficult to manipulate. Additionally, these solutions may come with a loss of stiffness, increasing the risk of the buckles deforming under load.

SUMMARY OF THE INVENTION

In light of the above, it is an object of the present disclosure to alleviate at least some of the drawbacks and to provide an improved cam buckle that allows for quick and easy operation.

The invention is defined by the appended independent claim, with embodiments being set forth in the appended dependent claims, in the following description, and in the drawings.

According to an aspect of the invention, there is provided a buckle for fastening a load strap, comprising a buckle frame having two substantially parallel side arms, and a crossbar extending between the side arms along a main axis, the main axis being substantially perpendicular to the side arms. A cam is arranged between the side arms, the cam being pivotable between a clamping position, in which a load strap inserted between a gripping portion of the cam and the crossbar is clamped, and a release position, in which a clearance between the gripping portion and the crossbar is increased. The buckle is characterized in that the crossbar forms part of a locking element which is displaceable between a closed position, in which the crossbar extends between the side arms such that a load strap positioned between the cam and the crossbar is laterally constrained by the side arms, and an open position, in which the crossbar is separated from at least one of the side arms, such that a load strap is laterally insertable between the cam and the crossbar.

The present invention is at least partly based on the realization that displacing the locking element may provide great ease of access for laterally inserting a load strap. The integrity of the buckle frame is maintained, increasing the stiffness of the buckle and its ability to withstand tension from a load strap.

In some embodiments, the locking element is displaceable such that the main axis of the crossbar remains perpendicular to the side arms during a displacement between the closed position and the open position of the locking element. This allows the crossbar to be aligned with the load strap irrespective of the position of the locking element. For instance, in the open position of the locking element, the load strap may be placed in contact with the crossbar and guided into a correct position in the buckle by the displacement from the open position to the closed position of the locking element.

The locking element may further be pivotably connected to a side arm and pivotably displaceable between the closed position and the open position of the locking element. This provides a reliable and precise mechanism for displacing the locking element, making it very easy to manipulate reliably.

Such a pivotable locking element may comprise an attachment arm extending between an end portion of the crossbar and an attachment portion pivotably connected to a side arm of the buckle frame, such that the pivot axis of the locking element is parallel to but offset with respect to the main axis of the crossbar. Such a construction provides a compact buckle while allowing for easy access for laterally inserting the load strap.

Alternatively, the locking element may be displaceable by translation along a direction perpendicular to the main axis of the crossbar.

In another alternative, the locking element may be slidably displaceable along its main (longitudinal) axis.

In some embodiments, each side arm may comprise an abutment adapted to engage a respective end portion of the crossbar, in the closed position of the locking element, and the locking element may be locked in the closed position by the cam when the cam is in the clamping position. This allows the abutments to determine the location of the crossbar, relative to the buckle frame, when the locking element is in the closed position. It ensures that a tension force transferred to the crossbar from a load strap in tension can be effectively transferred to the buckle frame. It further ensures that a clamped load strap can only be released by pivoting the cam from its clamping position to its release position.

The buckle may further comprise a biasing element, biasing the cam toward the clamping position. This reduces the risk of accidentally releasing a clamped load strap and/or displacing the locking element from its closed position to its open position.

The buckle frame may further comprise a second crossbar fixedly connecting the side arms of the buckle frame, the second crossbar forming an anchor for attaching one end of a load strap. This increases the stiffness of the buckle frame. Additionally, it allows for different ways to attach a load strap, such as sewing an end of the load strap around the crossbar or using a hook connected to the load strap.

DETAILED DESCRIPTION OF THE DRAWINGS

FIGS.1-4show an embodiment of a cam buckle1for fastening a load strap according to an aspect of the present invention. The cam buckle1comprises a pivotable cam30and a crossbar21forming part of a pivotably displaceable locking element20. The cam30and locking element20are pivotably connected to a U-shaped buckle frame10which is made of two parallel side arms12,13connected by a second crossbar11. The two side arms12,13are thin plates of similar dimensions, generally aligned and facing each other, with the second crossbar11transversally arranged between respective end portions of the side arms12,13.

The dimensions of the buckle frame10, such as the length, width and thickness of the side arms12,13, the length and thickness of the connecting second crossbar11, as well as the dimensions of the locking element20and of the cam30, may be chosen to best fit an intended size of a load strap to be used and the anticipated load to withstand. For example, the cam buckle may be sized to accommodate a load strap of 25 mm, 35 mm, 45 mm or 50 mm in width. The buckle frame10, locking element20and cam30may for example be made of a metallic material or hard plastic. The buckle frame may be manufactured as a single piece, for example by casting or moulding, or by joining separately manufactured side arms12,13and second crossbar11, for example by welding.

With reference toFIGS.2and3, the cam30is pivotably connected to generally medial portions of the side arms12,13, with a pivot axis A parallel to the crossbars11,21and perpendicular to the side arms12,13. The cam30is pivotable between a clamping position, shown inFIG.2, and a release position, shown inFIG.3. On one side of its pivot axis A, the cam30has a gripping portion32, shown inFIG.3. A biasing element34, connected to the buckle frame10and to the cam30, biases the cam30towards its clamping position, in which the gripping portion32is pushed against the crossbar21. The gripping portion32of the cam30has a serrated structure formed by a plurality of parallel teeth extending along the gripping portion32, parallel to the pivot axis A of the cam30. Alternatively, the surface of the gripping portion32could for example be knurled. On the other side of its pivot axis A, the cam30has an actuating portion33, configured to be pressed by a user to push the cam into its release position.

The locking element20is arranged with the crossbar21extending between the side arms12,13at the opposite end portions of the side arms12,13relative to the second crossbar11. The locking element20has an attachment arm24extending perpendicular to the crossbar21between an end portion of the crossbar21and an attachment portion25. The locking element is pivotably connected to one side arm12at the attachment portion25, with a pivot axis B parallel to the crossbar21. The end portion of the side arm13opposite the end portion of the side arm12to which the locking element is connected has a chamfered edge16.

On the inside of each side arm12,13, a ledge14,15extends along an edge of the side arm12,13between the attachment portion25of the locking element20and the second crossbar11. Closest to the locking element20, the ledge14,15has an arcuate shape, partly following the contour of the respective end portions of the crossbar21.

As shown inFIG.5, the attachment arm24has a hook shape, creating a trough28aligned between the end portion of the crossbar21and the attachment portion25. InFIGS.2and3, the trough28accommodates part of the ledge14that follows the contour of the end portion of the crossbar21. Further, the attachment portion25has two prongs26,27straddling the side arm12to which the locking element20is connected. The locking element20may be connected to the side arm12by a riveted joint through the two prongs26,27and the side arm12, or by any appropriate joint allowing the locking element to pivot. The attachment portion25could alternatively comprise a single prong26.

As further shown inFIG.5, the crossbar21of the locking element20has an asymmetric cross-section, with a generally flat portion22. The flat portion22, Like the gripping portion32of the cam30, this flat portion22of the crossbar21has a serrated structure formed by a plurality of parallel teeth extending along the crossbar21between end portions of the crossbar21. In the cam buckle1as shown inFIG.2, the flat portion22of the locking element20and the gripping portion32of the cam30are facing each other (and thus not visible inFIG.2). The end portion of the crossbar21opposite the attachment arm24has an end cap23.

The cam buckle1as shown inFIGS.2and3may be used as a traditional cam buckle. The actuating portion33of the cam30is pushed on by a finger of a user, in order to pivot the cam30toward its release position, as shown inFIG.3. With the cam30in the release position, there is a clearance between the griping portion32and the crossbar21. An end of a load strap may be inserted into this clearance and be freely moved. When the user releases the pressure on the actuating portion33, the cam30returns to its clamping position thanks to the biasing element34, and sandwiches the load strap between the gripping portion32and the crossbar21. The load strap is then pulled through the cam buckle1until the slack in the strap is removed and a desired tension is created. The end of the load strap is inserted in the cam buckle1such that the pulling on the strap to remove slack occurs in a direction going from the clamping position to the release position of the cam30. The tension in the strap pulls the gripping portion32of the cam30toward the crossbar21, thus increasing the clamping force on the strap, securing it in place.

The locking element20is pivotable between a closed position, shown inFIGS.2and3, and an open position, shown inFIG.4. When the locking element20is in the open position shown inFIG.4, an opening is created between the crossbar21and one of the side arms13. The opening allows a load strap40to be inserted laterally as illustrated by the arrow inFIG.4. The chamfered edge16of the side arm13increases this opening, facilitating the insertion of the load strap40. Subsequently, the locking element20is pushed back toward the closed position seen inFIG.2, leaving the load strap40constrained laterally between the side arms12,13and on the flat sides of the load straps by the crossbar21and the cam30, respectively.

The ledge14,15acts as an abutment for the locking element20when the locking element is in the closed position. The ledge14,15thus restricts the locking element20from further pivoting about axis B once the locking element20has reached its closed position, when pivoting from the open position to the closed position of the locking element20. Conversely, when the locking element20is in the closed position, the cam30restricts the locking element20from pivoting back about axis B toward the open position, as long as the cam30is in the clamping position shown inFIG.2.

In other words, the locking element20in the closed position is locked in place by the ledge14,15on one side and the cam30in clamping position on the other side, albeit with some clearance between the crossbar21and the cam30to accommodate a load strap therebetween. When the actuating portion of the cam30is pushed and the cam30pivots to its release position, as shown inFIG.3, the locking element20is allowed to pivot from its closed position to its open position. In so doing, the crossbar21follows a path going first inward, toward the middle of the buckle1, and away from the ledge14,15, until an opening is created between the crossbar21and the side arm13opposite the side arm12to which the locking element20is connected. Displacing the locking element20from the open position to the closed position only requires pushing on the crossbar21(or another part of the locking element20) to pivot in the other direction. When the crossbar21comes into contact with the cam30, it pushes the cam30to slightly pivot toward its release position until the locking element20is free to reach the closed position. The biasing element ensures that the cam30directly returns to the clamping position after passage of the crossbar21. This quick movement of the cam30produces a click sound, indicating to the user that the locking element20is locked in place.

The ledge14,15contributes to the strength of the buckle frame1. Additionally, it allows for an effective transfer of load from the crossbar21to the buckle frame1. As a load strap in tension pulls on the crossbar21, the end portions of the crossbar21engage with the respective ledge14,15. In this way, the load is distributed substantially equally between the two side arms12,13. Advantageously, the strength of the cam buckle1is not only dependent on the strength of the joint between the buckle frame10and the locking element21.

FIG.6shows an alternative embodiment of the cam buckle100. The cam buckle100comprises a pivotable cam30and a slidably displaceable locking element120forming a crossbar121connected to a U-shaped buckle frame110. The buckle frame110is made of two side arms112,113connected by a second crossbar111. The two side arms112,113are thin plates of similar dimensions, generally aligned and facing each other, with the second crossbar111transversally arranged between respective end portions of the side arms112,113.

The locking element is slidably displaceable between a closed position, in which the crossbar121extends between the two side arms112,113, and an open position, in which the crossbar121is separated from one side arm113, as shown inFIG.6. The displacement of the locking element occurs along the main axis of the crossbar121, through an opening in the other side arm112.

The cam30is pivotably connected to generally medial portions of the side arms112,113, with a pivot axis parallel to the crossbars111,121and perpendicular to the side arms112,113. The cam30is pivotable between a clamping position and a release position. On one side of its pivot axis, the cam30has a gripping portion32. A biasing element, connected to the buckle frame110and to the cam30, biases the cam30towards its clamping position, in which the gripping portion32is pushed against the crossbar121, when the crossbar121is in the closed position of the locking element120.

When the locking element120is in the closed position, the cam buckle100may be used as a traditional cam buckle, in the same way as the cam buckle1described inFIGS.2and3. When the locking element120is in the open position as shown inFIG.6, an opening is created between the crossbar121and one of the side arms113. The opening allows a load strap to be inserted in the cam buckle100without having to thread an end of the load strap between the crossbar121and the cam30. The locking element120is subsequently returned to its closed position, leaving the load strap constrained laterally between the side arms112,113and on the flat sides of the load straps by the crossbar121and the cam30, respectively.

The skilled person in the art realizes that the present invention by no means is limited to the embodiments described above. The features of the described embodiments may be combined in different ways, and many modifications and variations are possible within the scope of the appended claims. In the claims, any reference signs placed in parentheses shall not be construed as limiting to the claim. The word “comprising” does not exclude the presence of other elements than those listed in the claim. The word “a” or “an” preceding an element does not exclude the presence of a plurality of such elements.