Abstract:
A tie-down assembly for securing an article by a strap has a frame to which one end of the strap is immovably connected and a winding shaft about which the other end of the strap is wound and unwound. A handle pivoted to the frame engages ratchet teeth on the winding shaft to rotate the winding shaft in a strap take-up direction when the handle moves from a second to a first position while not rotating the winding shaft when the handle moves the first toward the second position. A lock mechanism actuated by a key is provided to positively and selectively lock the handle to the frame when the handle is in the second position.

Description:
This invention relates generally to a tensioning apparatus for a lashing strap, and more particularly to a lock for the tensioning apparatus. 
     The invention is particularly applicable to and will be described with specific reference to a tensioning apparatus which employs ratcheting mechanisms for tensioning and releasing the lashing strap. However, those skilled in the art will recognize that the invention may have broader applications and could be utilized in tensioning apparatuses that utilize crank mechanisms other than ratchets. 
     INCORPORATION BY REFERENCE 
     The following patents listed below are incorporated herein by reference and made a part hereof so that details related to the ratcheting mechanisms illustrated therein need not be repeated in detail in this patent: 
     1. U.S. Pat. No. 5,426,826 to Takimoto, issued Jun. 27, 1995, and entitled RATCHET BUCKLE ASSEMBLY; 
     2. U.S. Pat. No. 5,282,706 to Anthony, et al., issued Feb. 1, 1994, and entitled RETRACTABLE TIE-DOWN ASSEMBLY; and, 
     3. U.S. Pat. No. 5,271,606 to Kamper, issued Dec. 21, 1993, and entitled TENSIONING RATCHET FOR A LASHING STRAP. 
     The materials incorporated by reference, while included in this invention herein, do not, per se, form the present invention. 
     BACKGROUND OF THE INVENTION 
     It is well known that in order to transport goods, equipment, and vehicles, it is necessary to secure these items with a plurality of tie-down straps. The number of tie-down straps required generally depends on the size and type of goods to be hauled by the vehicle. 
     In prior art tie-down assemblies, each tie-down strap usually has a hook at each end and some mechanism for adjusting the length of the strap that is disposed between the two ends. The adjusting mechanism is often a ratchet tightening device disposed between the ends of the strap. Conventional tie-down apparatuses generally include a tensioning apparatus of the type that includes a U-shaped frame having side walls with a rotatable spindle bridging the space between the side walls. One end of the lashing strap is fixed to the frame and the other lashing strap end is threaded onto the spindle. A tensioning handle with a pawl is pivotally mounted to the frame, and cooperates with a ratchet wheel affixed to the spindle. Movement of the handle in one direction results in incremental angular movement of the spindle by engagement of the handle pawl with ratchet wheel. A spring bias arrangement is provided for release of handle pawl engagement with the ratchet wheel. Such tensioning apparatuses serve as tensioning and tie-down devices for actual straps, with lashing straps constituting the preferred embodiment of the tensioning and tie-down means, which may also be in the form of steel cables. With lashing straps, goods to be transported are secured with the necessary lashing tension to retain their position on transporting means, for example, the beds of trucks or the rooftops of automobiles. 
     Typical operation of a tie-down assembly includes encircling the load to be secured, pulling the loose end of the lashing strap through a slot within the spindle as far as this is possible without resistance. Then the spindle is rotated by pivoting a tensioning handle back and forth. The tensioning handle drives an externally-toothed ratchet wheel of the ratchet device in the tensioning direction of the spindle (or winding shaft), so that the lashing strap is wound around the winding shaft which acts in the manner of a wind-up reel and is thus charged with an increasing lashing tension. 
     One of the drawbacks of the prior art tie-down assembly straps is the fact that the ratchet mechanism does not secure the handle to the frame. The result is that one or more of the tie-down straps could be unintentionally released or the tension otherwise sufficiently reduced such that the goods that were once secured may be released from the trailer or rooftop of an automobile. 
     The prior art has, however, recognized that the lashing strap must be locked to maintain strap tension, and discloses a tie-down assembly that includes a locking mechanism mounted to the frame tensioning apparatus such as shown in U.S. Pat. No. 5,282,706. The locking arrangement described in the prior art represents a second spring actuated member engaged with the ratcheting spindle to allow the spindle to rotate only in a take-up direction unless the spring bias is disabled. The spring actuated member that engages the ratcheting spindle in the prior art is subject to wear and vibration on a moving vehicle and conceivably, the spring force exerted on the member will eventually be insufficient to retain the ratcheting spool in a fixed position. This could result in undesirable slack in the tensioning strap. More importantly, the spring actuated member that engages the spindle does not positively lock the handle to the frame, and cannot prevent intentional release of the ratchet spool by an unauthorized person desiring to remove the secured goods (i.e. theft). 
     As previously discussed, the major drawback of the existing tensioning apparatuses is that in the final load securing stage, the tensioning handle remains unsecured. The lack of a positive securement mechanism for the tensioning handle enables inadvertent, accidental, and intentional or unintentional dislodgement. Dislodgement of the tensioning handle may result in releasing the tension of the lashing strap, thereby allowing the goods that are being transported to be released from the transport vehicle. Due to the fact that the lashing straps are typically used for securing goods on a moving vehicle, releasing of these goods from the vehicle may result in catastrophic accidents to vehicles and passengers following behind the subject vehicle. A principal drawback of the prior art device is that the tensioning apparatus with an unsecured tensioning handle allows unwanted tampering with the lashing strap and also allows potential theft of the secured goods. 
     SUMMARY OF THE INVENTION 
     It is therefore one of the major objects of the invention to provide a safe and lockable tensioning apparatus. 
     This object, along with other features of the invention, is achieved in a tie-down assembly for securing an article by a strap which includes a frame and a winding shaft journaled for rotation in the frame in a first payout direction and in an opposite second take-up direction whereby the length of the strap is shortened by being wound around the winding shaft in the take-up direction, and lengthened by being unwound from the winding shaft in a payout direction. The assembly additionally includes a ratchet wheel having ratchet teeth rotatable with the winding shaft, a handle associated with the winding shaft and movable from a second to a first position for rotating the winding shaft an incremental angle in the take-up direction while not rotating the winding shaft when moved from the first to the second position. The assembly further includes a spring biased handle pawl for engaging the ratchet teeth to allow rotation of the winding shaft by the handle in the take-up direction and prevent rotation in the payout direction. The spring biased handle pawl is capable of being moved out of engagement with the ratchet wheel to allow strap payout. In accordance with the invention, a key operated latch mechanism is provided for selectively locking the handle to the frame in the second position to, among other things, prevent theft of the goods secured by the tie-down assembly. 
     In accordance with another aspect of the invention, the key operated latch mechanism includes the handle center portion having a lock opening therein and a female latch member is connected to and straddles the frame side walls. The female latch member has a configured latch opening aligned with the lock opening when the handle is in the second position and a lock tumbler connected to said lock housing passes through the lock opening. A simple and effective lock is achieved by a rotatable male latch member attached to the base of the lock tumbler and configured to pass through the latch opening when the lock tumbler is in an unlocked condition and the handle is in the second position. In addition, the rotatable male latch member is unable to pass through the latch opening when the lock tumbler is in a locked condition. 
     In accordance with yet another aspect of the invention, the key operated latch mechanism includes the handle center portion having a lock opening therein and a female latch member having a top portion is connected to the frame. The female latch member is aligned with said lock opening so that the top portion of the female latch member extends through said lock opening when the handle is in the second position. Importantly, the top portion of the female latch member has a latch opening therethrough so that any conventional locking bolt adapted to extend through said latch opening can be provided for preventing movement of the handle relative to the frame. 
     In accordance with a more specific aspect of the invention, the locking bolt can simply be the U-shaped member of a conventional padlock. 
     In accordance with a still general aspect of the invention, a retractable tie-down assembly for securing an article by a strap is provided, which includes a frame to which one end of the strap is immovably secured. The assembly includes a winding shaft journaled for rotation in the frame and about which the strap is wound when the winding shaft is rotated in a take-up direction and unwound when the winding shaft is rotated in a payout direction. The tie-down assembly includes a handle pivotally mounted to and manually rotatable relative to the frame between first and second positions and an engagement mechanism for rotating the winding shaft in the retracting direction when the handle is moved from the second toward the first position while not rotating the winding shaft when the handle moves from the first toward the second position. A locking mechanism actuated by a key positively locks the handle to the frame when the handle is in the second position, whereby the lock is effective to lock the tie-down assembly irrespective of the particular type of engagement mechanism used in the tie-down assembly. 
     It is thus an object of the invention to provide a lockable tensioning apparatus. 
     It is another object of the invention to provide a safe tensioning apparatus. 
     Yet another object of the invention is to provide an economic, rugged and reliable locking mechanism for a tie-down ratchet assembly. 
     Still another object of the invention is to provide an inexpensive locking mechanism for a tensioning apparatus of the type described herein. 
     Still another object of the invention is to provide a lock mechanism which can be easily implemented or incorporated into existing tensioning apparatus. 
     These and other objects, features and advantages of the present invention will become apparent to those skilled in the art upon reading the detailed description of the invention as set forth below, taken together with the drawings which will be described in the next section. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention may take physical form in certain parts and arrangement of parts, a preferred embodiment of which will be described in detail and illustrated in the accompanying drawings which form a part hereof and wherein: 
     FIG. 1 is a perspective view of a pickup truck, all-terrain vehicle, and the tie-down assembly according to one embodiment of the present invention; 
     FIG. 2 is a top elevational view of the tie-down assembly in the closed position; 
     FIG. 3 is a side view of the tie-down assembly in the second position; 
     FIG. 4 is a side sectional view identical to FIG. 3 except showing both ratchet wheel engagement mechanisms; 
     FIG. 5 is a top elevational view of the tie-down assembly in the first position; 
     FIG. 6 is a bottom perspective view of the tie-down assembly in the first position; 
     FIG. 7 is a front sectional view of the tie-down assembly in the second position; 
     FIG. 8 is a side view of another embodiment of the tie-down assembly showing the use of a cable in place of a strap; 
     FIG. 9 is a side sectional view of another embodiment of the tie-down assembly showing an alternative embodiment of the invention; and, 
     FIG. 10 is a front sectional view of the tie-down assembly in the second position of the alternative embodiment of the invention illustrated in FIG.  9 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now in detail to the drawings, wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only and not for the purpose of limiting the invention, FIG. 1 illustrates a typical cargo area  10  for a pickup truck, which contains a secured all-terrain vehicle (ATV)  11 . ATV  11  is secured by lashing straps  12 ,  14  connected at one of their ends to a locking ratchet assembly  20 . Lashing strap  12  is a variable length lashing strap and lashing strap  14  is a fixed length lashing strap. At the opposite end of each lashing strap  12 ,  14  is permanently affixed a securement hook  13 . Securement hooks  13  are used for attachment to cargo area  10  and the equipment to be secured i.e. ATV  11 . Locking ratchet assembly  20  (to be described below) supplies the necessary means for tightening variable length lashing strap  12  whereby a securing force is applied to securement hooks  13  of both lashing straps  12 ,  14  and ultimately enables securement of the equipment. The application displayed in FIG. 1 is only an example of the many possible applications of the invention. Alternatively, variable and fixed length lashing straps  12 ,  14  could be replaced by a single lashing strap with ends connected to locking ratchet assembly  20 . The single lashing strap circumscribes an object to be secured and a stationary support against which the object is to be secured. Locking ratchet assembly  20 , when actuated, reduces the length of the encircling lashing strap until the object is firmly bound to the stationary support. As used herein and in the claims, “strap” means either two separate straps  12 ,  14  as shown in FIG. 1, or one unitary strap as described. For definitional purposes, then, the “strap” shown in FIG. 1 is a lashing strap having a fixed, non-changing length section  14  and a variable length changing section  12 . 
     FIG. 2 details locking ratchet assembly  20  in the second position. Locking ratchet assembly  20  for tightening lashing straps  12 ,  14  is constructed of the following components. Locking ratchet assembly  20  has a U-shaped frame  40  comprised of a pair of parallel extending frame side walls  41 ,  42  and a frame center portion  43  interposed therebetween. Locking ratchet assembly  20  further includes a winding shaft  44  constructed of a pair of semicircular winding shaft plates  45 ,  46  with winding shaft  44  being supported between and extending through circular openings  52  in frame side walls  41 ,  42 . Locking ratchet assembly  20  also includes a U-shaped tensioning handle  60  constructed of a pair of parallel extending handle side walls  61 ,  62  having a grip plate  63  and a handle center portion  68  interposed therebetween. Locking ratchet assembly  20  further comprises a pair of ratchet wheels  21 ,  22  mounted on winding shaft  44 . Additionally, locking ratchet assembly  20  includes a frame pawl  23  for engaging ratchet teeth  28  during rotation. And, locking ratchet assembly  20  has a handle pawl  24  for rotatably driving ratchet wheels  21 ,  22  so that variable length lashing strap section  12  is wound on winding shaft  44 . 
     In locking ratchet assembly  20  of the invention, frame  40 , tensioning handle  60 , and winding shaft  44  are rotatable independently of each other. Ratchet wheels  21 ,  22  are fixedly mounted on winding shaft  44  so as to be rotatable together with winding shaft  44 . Frame pawl  23  is slidably mounted in a pair of frame longitudinal slots  53 ,  54  formed in frame side walls  41 ,  42  and is abutted against ratchet teeth  28  under the influence of a force exerted by a frame spring  25 . Handle pawl  24  is slidably mounted in a pair of handle longitudinal slots  64 ,  65  and is engaged with ratchet teeth  28  to rotatably drive winding shaft  44  so that variable length lashing strap  12  is wound on winding shaft  44  as winding shaft  44  rotates. Handle pawl  24  is abutted against ratchet teeth  28  under the influence of a force exerted by a handle spring  66 . Frame pawl  23  is engaged with ratchet teeth  28  to prevent winding shaft  44  from being reversely rotated. Additionally, semicircular winding shaft plates  45 ,  46  are supported by a circular opening  69  in handle side walls  61 ,  62  and circular opening  52  in frame side walls  41 ,  42 , and are connected to winding shaft washers  47 ,  48  and pins  26 ,  27 . Semicircular winding shaft plates  45 ,  46  extend through corresponding semicircular openings  55  in winding shaft washers  47 ,  48 . Pins  26 ,  27  extend through holes  56  in semicircular winding shaft plates  45 ,  46  to allow rotation and to prevent axial movement of semicircular winding shaft plates  45 ,  46 . The front elevational view of FIG. 2 also displays a lock housing  70  and a key slot  71 . Locking ratchet assembly  20  in the closed position prevents variable length lashing strap section  12  from release. Fixed length lashing strap section  14  is rigidly affixed to flame  40  by a lashing bar  49  extending through corresponding circular openings  51  in frame side walls  41 ,  42 . 
     Referring now to FIGS. 3 and 4, locking ratchet assembly  20  is shown from the side view in the second position. Fixed length lashing strap section  14  is attached to lashing bar  49 . In the second position, notch  67  in handle side wall  62  engages frame pawl  23  with ratchet teeth  28  so that winding shaft  44  is prevented from being reversely rotated. As can be seen in FIG. 4, frame spring  25  and handle spring  66  exert the requisite force on frame pawl  23  and handle pawl  24 , respectively. The biasing forces exerted by frame spring  25  and handle spring  66  are necessary for the proper functioning of locking ratchet assembly  20 . The force exerted by frame spring  25  and handle spring  66  will diminish over time through normal use and exposure to the elements. 
     An operator of locking ratchet assembly  20 , in order to tighten variable length lashing strap section  12 , will grasp grip plate  63 , which is part of the handle center portion  68 , and exert an upward force thereby engaging ratchet wheels  21 ,  22  with handle pawl  24 . As the upward force on grip plate  63  continues, ratchet wheels  21 ,  22  turn along with winding shaft  44  so that variable length lashing strap section  12  is wound on winding shaft  44 . Upon completing one stroke of tensioning handle  60 , tensioning handle  60  is returned to the starting (second) position. During the return motion of tensioning handle  60  to the second position, tensioning handle  60  moves independently from frame  40 , winding shaft  44 , and ratchet wheels  21 ,  22 . This independent movement of tensioning handle  60  allows variable length lashing strap section  12  to remain fixed. Tensioning handle  60  is repeatedly moved from the second to the first and back to the second position until the desired tension has been placed on lashing strap sections  12 ,  14 . Tensioning handle  60  is then returned to the second position in which handle pawl  24  and frame pawl  23  are engaged with ratchet teeth  28 . As stated previously, notch  67  in handle side wall  62  engages frame pawl  23  and provides one means for preventing the disengagement of frame pawl  23  with ratchet wheels  21 ,  22 . 
     The apparatus as described thus far is conventional and well known in the field. 
     A key operated latch mechanism designated generally by reference numeral  80  is connected to and passes through a lock opening  59  in handle center portion  68 . Latch mechanism  80  includes a lock tumbler  72  passing through lock opening  59  and secured to tensioning handle  60  by means of a hex nut  73 . A male latch member  74  is connected to lock tumbler  72  by a lock screw  75 . When a key  76  is turned in a key slot  71  in lock tumbler  72 , male latch member  74  is rotated about the longitudinal axis of lock tumbler  72 . The rotation of male latch member  74  allows engagement and disengagement from a female latch member  77  having a latch opening  81 . Latch opening  81  in female latch member  77  allows passage therethrough of male latch member  74  when key  76  places lock tumbler  72  in an unlocked condition. Subsequent rotation of male latch member  74  by key  76  causes engagement with an underside  82  of female latch member  77  preventing withdrawal through latch opening  81 . Thus, in the engaged position, key operated latch mechanism  80  prevents the withdrawal of male latch member  74  from female latch member  77 , and secures tensioning handle  60  to frame  40  to prevent rotation of ratchet wheels  21 ,  22 , which ultimately prevents movement of lashing strap sections  12 ,  14 . 
     Referring now to FIGS. 5 and 6, there is shown a bottom view of key operated latch mechanism  80  in its first or unlocked position. Latch mechanism  80 , specifically male and female latch members  74 ,  77 , respectively, is displayed. Note that male latch member  74  can be withdrawn from latch opening  81 . Additionally, handle pawl  24  along with its handle spring  66  and frame pawl  23  along with its frame spring  25  are readily apparent. Most of the components of key operated latch mechanism  80  are preferably made from heavy gauge hardened steel, or other suitable materials which are well-known in the art. 
     Referring now to FIG. 7, key operated latch mechanism  80  is shown from a front sectional view in its second or locked position. As shown, male latch member  74  is rotated on underside  82  of female latch member  77 , thereby preventing withdrawal of male latch member  74  through latch opening  81  and thus, preventing operation of the tensioning apparatus, either to unlock locking ratchet assembly  20  or to alter the tension on lashing strap sections  12 ,  14 . 
     Referring now to FIG. 8, there is shown another conventional embodiment of locking ratchet assembly  20 , which uses lashing cables  16 ,  18  in place of lashing straps  12 ,  14 . 
     In operation, when the slack in variable length lashing strap section  12  is taken up on winding shaft  44 , locking ratchet assembly  20  will be configured as shown in FIGS. 3,  4 , and  8 . The next step is to engage ratchet teeth  28  with frame pawl  23  and handle pawl  24 . Upward movement of tensioning handle  60  from a second to a first position moves handle pawl  24  to cause simultaneous rotation of ratchet wheels  21 ,  22  and winding shaft  44 . Rotation of winding shaft  44  further tightens variable length lashing strap section  12 . Tensioning handle  60  can then be returned to the second position where the ratcheting cycle can be repeated. This ratcheting cycle is repeated until variable length lashing strap section  12  has achieved its desired tension. Once the desired tension has been achieved in variable length lashing strap section  12 , tensioning handle  60  is returned to its second position and locked by turning key  76  in key slot  71 . Turning of key  76  rotates male latch member  74  which prevents withdrawal of male latch member  74  from latch opening  81  in female latch member  77 , and secures tensioning handle  60  to frame  40 . This securement prevents further rotation of ratchet wheels  21 ,  22 , and also prevents release of tension in variable length lashing strap section  12 . 
     Referring now to FIGS. 9 and 10, an alternative embodiment of the key operated latch mechanism is shown from a side sectional view and a front sectional view. In this embodiment, frame  40  includes an L-shaped locking member portion  50  which protrudes through an opening  159  in tensioning handle  60  when tensioning handle  60  is in the second position. Locking member portion  50  contains a latch opening  181  in its top portion  177  which allows a locking bolt or a U-shaped locking member  79  of a standard padlock  78  to pass therethrough. In operation, once the desired tension has been achieved in variable length lashing strap section  12 , tensioning handle  60  is returned to the second position as described above. When tensioning handle  60  is in the second position, U-shaped locking member  79  of a standard padlock  78  can be passed through latch opening  181  of locking member portion  50 . Tensioning handle  60  can then be locked either with a combination lock or a key lock. Locking padlock  78  prevents disengagement of tensioning handle  60  from frame  40 . This securement prevents further rotation of ratchet wheels  21 ,  22 , and also prevents release of tension in variable length lashing strap section  12 . 
     With reference to the alternative embodiment of the invention disclosed in FIGS. 9 and 10, it will be appreciated that the tie-down ratchet assemblies will in many situations be used alongside or in close proximity to identical tie-down assemblies. Having a multitude of tie-down assemblies located in close proximity to each other facilitates the use of a cable lock extending through a series of latch openings  181  in top portions  177  of locking member portion  50  to allow securement of several tie-down ratchet assemblies with one lock element. 
     The preferred and alternative embodiments of the invention discussed above are desired because each embodiment allows insertion of a positive, manually actuated lock with little modification to conventional structures used in a tensioning apparatus. In each embodiment, the frame of the tie-down apparatus is modified in a strengthening manner while the provision of an opening in the tensioning handle as described does not adversely affect the strength of the tensioning handle. Thus, a lock mechanism can be mounted to these sturdy elements of the tie-down assembly to provide a secure, non-yielding locking action. However, in accordance with the broader scope of the invention, different locking arrangements, other than those illustrated, may be employed. 
     For example, either handle side wall  61 ,  62  of tensioning handle  60  and mating frame side walls  41 ,  42  of frame  40  can be used to lock tensioning handle  60  to frame  40 . Conceptually, holes can be provided in handle side wall adjacent frame side wall which align with one another when tensioning handle  60  is in its second position. Thus, when tensioning handle  60  is in the second position, a locking bolt can be inserted through the aligned holes. 
     Alternatively, a telescoping lock arrangement may be utilized, such as disclosed in assignee&#39;s well-known U.S. Pat. No. 4,738,127 to Johnson, issued Apr. 19, 1988. A serrated rod, such as shown in Johnson, can be mounted to pivotally extend from the base or center frame portion  43  of frame  40 . The Johnson lock can be mounted in a handle opening similar to that discussed above. Alternatively, the Johnson lock can be mounted in lock opening  59  but in a position away from where the user grips tensioning handle  60 . The rod telescopes through the Johnson lock as tensioning handle  60  is moved from its first to second position and second to first position. This arrangement allows positive locking of the handle at any position and without having to return the handle to its second position. 
     The invention has been described with reference to a preferred and alternative embodiments. It is believed that modifications and alterations to the embodiments disclosed will suggest themselves to those skilled in the art upon reading and understanding the detailed description set forth herein. It is intended to include all such modifications and alterations insofar as they come within the scope of the present invention.