Implements or apparatus for applying pushing or pulling force – Portable implements or apparatus for tensioning flexible... – Including rotatably driven drum for engaging either material...
Reexamination Certificate
2001-07-06
2003-04-15
Marcelo, Emmanuel (Department: 3654)
Implements or apparatus for applying pushing or pulling force
Portable implements or apparatus for tensioning flexible...
Including rotatably driven drum for engaging either material...
C024S0680CD
Reexamination Certificate
active
06547218
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to fastening devices and, more particularly, to ratchet buckles, strap tensioners, cargo retraining devices and the like for tightening and tensioning straps.
2. Related Art
Ratchet buckles, also commonly referred to as cargo restraining devices and strap tensioners are commonly used for tightening and securing straps, ropes, chains or other tie-down tensioning lines. Generally, conventional ratchet buckles include a ratchet mechanism and a securing mechanism for retaining the strap in a tensioned condition. Conventional ratchet buckles for tightening and/or tensioning straps are described, for example, in U.S. Pat. Nos. 2,889,136, 4,185,360, 4,227,286, 4,199,182, 4,324,023, 4,570,305, 4,542,883, 5,282,296, and others.
Although such ratchet buckles are quite effective in tensioning straps, there are a number of drawbacks associated with using conventional ratchet buckles under certain circumstances. One such drawback of is that a limited length of the lashing strap is wrapped around the drum or reel of the ratchet buckle in response to a single tensioning operation. As a result, a large number of tensioning operations must be performed to uptake lengths of the lashing strap. This oftentimes requires significant time performing numerous manipulations of the ratchet buckle.
Another drawback manifests itself when the conventional ratchet buckles are secured and fully tensioned, restraining a load under a tensioned lashing strap. It is often difficult to release the tension on the lashing strap to remove or adjust a secured load. As a result, fragile loads are sometimes damaged in the process of loosening or de-mounting the lashing strap and ratchet buckle.
What is needed, therefore, is an apparatus that enables an operator to quickly and easily adjust a lashing strap when performing tightening/securing and loosening/releasing operations with a ratchet buckle.
SUMMARY OF THE INVENTION
The present invention is a ratchet and cam buckle tensioning assembly, interposed between a lashing strap tensioned by the ratchet buckle and a lead strap tensioned by the cam buckle. The tensioning assembly enables an operator to quickly and conveniently pre-tension the lashing and lead straps by removing an un-tensioned length of the lead strap without having to operate the ratchet buckle. This advantageously enables the operator to utilize the ratchet buckle to tension the straps only when the requisite tensioning force cannot be provided by an unaided operator. That is, the ratchet buckle may be operated only to tension a lashing strap that has been pre-tensioned with the cam buckle, thereby facilitating the use of the combined assembly. As a result, the present invention saves an operator from having to operate the ratchet buckle multiple times to uptake slack in the lashing strap when the leveraged tensioning force provided by such a ratchet buckle is unnecessary.
In one aspect of the invention, a tensioning assembly for tightening and releasing a lashing strap and a lead strap is disclosed. The tensioning assembly includes a ratchet buckle for tensioning the lashing strap in stepped increments and a cam buckle for slidingly adjusting the lead strap. The cam buckle is connected adjacent to the frame member by an apparatus other than the lead and lashing straps. The ratchet buckle may be any known ratchet buckle. In one embodiment, the ratchet buckle includes a bifurcated frame member having a pair of opposing parallel arms between which a reel member and ratchet wheels are rotatably mounted. A latching plate is also slidably mounted between the arms for latching the ratchet wheels when the ratchet wheels are not being rotatably driven. The ratchet buckle also includes a lever member rotatably mounted on the reel member and having a pair of opposing side members between which a ratchet drive plate is slidably mounted for engaging and driving the ratchet wheel when the lever member is actuated.
In one preferred embodiment, the cam buckle housing and the ratchet buckle frame member are a unitary member, forming an single, integrated tensioning assembly. In another preferred embodiment, the cam buckle is permanently attached adjacent to the ratchet buckle. In one particular embodiment, the cam buckle is attached to the ratchet buckle with an intermediate strap. In this embodiment, the ratchet buckle frame member includes a first cross bar supported between the pair of opposing frame member arms, and the cam buckle includes side members attached to opposing sides of the pressure plate with a second cross bar supported between such side members. The intermediate strap is fixedly connected to the first and second cross bars, and is of such a length so as to place the cam buckle adjacent to the ratchet buckle.
In an alternative embodiment, the cam buckle includes a housing adapted to slidably receive the lead strap. The housing has a pressure plate with a first restraining surface over which the lead strap slides. Also included in the cam buckle is a pawl movably mounted to the housing. The pawl has a second restraining surface and is biased in an engaged position to restrain the lead strap between the first and second restraining surfaces so as to prevent movement of the lead strap in one or both directions. The pawl also may assume a disengaged position wherein the lead strap can move freely between the first and second restraining surfaces. In one embodiment, the cam buckle is unidirectional, preventing movement of the lead strap a single direction. Particularly, the pawl, when in the engaged position, prevents movement of the lead strap in a direction that loosens the lead strap while allowing movement of the lead strap in a direction that tensions the lead strap. In one specific embodiment, the housing has a rear portion facing toward the ratchet buckle and a front portion facing away from the ratchet buckle. The lead strap travels from the front portion to the rear portion of the housing to tension the lead strap and from the rear portion towards the front portion to loosed the lead strap. In this embodiment, the pawl is constructed and arranged to engage and prevent movement of the lead strap in a direction from the front portion of the housing toward the rear portion of the housing while allowing movement of the strap from the rear portion of the housing to the front portion of the housing.
In one embodiment, the pawl is pivotally mounted to the housing. In a specific implementation, the housing comprises a pressure plate and a pair of substantially parallel side members attached to the pressure plate. The pawl is pivotally mounted between the pair of housing side members such that the second restraining surface is in opposing juxtaposition to the first restraining surface. Generally, the cam buckle includes means for maintaining securely the first retraining surface of the pawl against the first restraining surface of the housing. In the embodiment wherein the pawl is pivotally mounted to the housing, the cam buckle preferably includes a torsion spring disposed about one end of the pivot pin. The torsion spring has a first extension arm in contact with the pawl and a second extension arm in contact with the housing. The torsion spring has a torque sufficient to maintain securely the first retraining surface of the pawl against the first restraining surface of the housing. The first and second restraining surfaces may be any suitable surfaces for retraining the selected type of lead strap. In one preferred embodiment wherein the lead strap is a webbing, the second restraining surface comprises serrations while the first restraining surface comprises grooves.
In another aspect of the invention a cargo retraining device is disclosed. The cargo retraining device includes a lashing strap having a free end and a securable end and a lead strap having a free end and a securable end. A ratchet buckle, interposed between the lashing strap and the lead strap is ratchetably connected to the lashing strap, increm
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