Abstract:
An add-on spring driven tensioner for a load restraint winch incorporates in an OEM embodiment or a reworked winch, an axially extended barrel portion of the tensioner that extends through the endplate of the winch, to withstand added bending stresses from the overhung tensioner. The loading provision for the tensioner limits spring tensioning to one half of a revolution. A reinforced winch structure includes a twin ratchet wheel, which can have spring-loaded ratchet pawls. A safety ratchet clip removably attached to the winch endplate can secure the ratchet pawl/pawls, in a positively engaged or a positively disengaged condition.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application is a Continuation-in-Part of application Ser. No. 10/225,357 filed Aug. 22, 2002, which is a Continuation-in-Part of application Ser. No. 09/532,080, filed Mar. 21, 2000, and of Ser. No. 09/661,081, filed Sep. 13, 2000, the specifications of which are embodied herein by way of reference. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    This invention is directed to a load restraint system, and in particular to a safety adaptation to a load restraint system, for retrofitting truck load winches, used for securing loads to flatbeds, trucks and the like, into a spring loaded safety winch, and to OEM spring-loaded winches.  
           [0004]    2. Description of the Prior Art  
           [0005]    The attachment of loads upon the beds of vehicles, for safe transportation, usually relies upon hold-down members, such as straps, chains and the like that are passed over the load and secured to the sides of the vehicle, and there tensioned.  
           [0006]    Tensioning of the hold-down members is usually effected by use of an in-situ, hand-operated winch to which one end of the hold-down member is attached.  
           [0007]    The winch has a drum, about which an end of the hold-down member is wound. The drum has a capstan which is rotated by means of a lever or Tommy-bar that is inserted into a selected hole in the drum capstan, and the bar is then cranked angularly, to wind the hold-down member onto the drum, and to tension it.  
           [0008]    The winch drum has a toothed ratchet wheel at one end, which may be located adjacent the capstan, or located at the opposite end of the winch, against which ratchet wheel a ratchet pawl engages, to prevent reversed, overhauling rotation of the drum, which would result in the loss of the tension that is applied to the hold-down member.  
           [0009]    The use of nylon or other straps of suitable plastic may provide a degree of elasticity to the load restraint system. However, despite such elasticity, there is a distressingly frequent loss of tension in the hold-down member, due to settling of the load. This loss in tension frequently results in a major shifting of the load, often with disastrous, and frequently fatal consequences for the trucker and often for other road users.  
           [0010]    In cases where cables or chains are used as the hold-down member, the maintenance of tension is an even greater problem, due to a substantial absence of elasticity and resilience in the hold-down member. Any settling of the load can lead to instantaneous loss of hold-down tension, which can then lead rapidly to shifting of the load. This particularly applies to loads such as logs.  
           [0011]    This problem of inadequate security of load attachment is currently leading towards legislation proposing that, in the case of road trucks, for every three hours of travel or 150 miles covered, the vehicle shall be halted and the tension of the load securing hold-down members be checked. As there are usually a significant number of load members and their associated winches along the length of a modern, extended transport truck and/or trailer, such further checking involves the expenditure of considerable further time and effort on the part of the driver.  
           [0012]    Added to this is the roadside hazard, affecting both passing traffic, in the event that there is no proper pull-off, and more particularly the truck driver, who is particularly vulnerable beside the truck, when preoccupied in pulling down with fill force against each of many winches, to re-tension the respective hold-down members.  
           [0013]    A particularly adverse factor is the the gross physical strain imposed upon the driver, particularly to the shoulders and back, the latter being especially vulnerable to injury, due to the repetitious pulling down, winch after winch, and time after time.  
           [0014]    Instances of severe frontal injury and even death have occurred, usually due to kick-back or dislocation and forcible discharge of the loading bar from the winch. One earlier attempt to deal with the problem is presented in U.S. Pat. No. Re. 30,307 (re-issued) Jun. 17, 1980 (Arbogast). This prior art arrangement had a hollow drum rotatably mounted in a frame, with an external eyelet on the drum for attachment of the loading cable thereto. The drum contained an unsupported helical spring. The drum had two ratchet wheel/pawl combinations, located at opposite ends of the winch frame. Each ratchet wheel also incorporated a capstan.  
           [0015]    A first ratchet wheel was connected to the drum, to prevent overhauling of the drum by the tensioned, load-restraining cable or chain; the second ratchet wheel was connected to one end of the helical spring. The other end of the helical spring was attached to the interior of the drum. In use, a tommy bar was inserted in the capstan of the first ratchet wheel, and the drum was rotated, to wind-on and tension the cable or chain. The tommy bar was then withdrawn, relocated in the capstan of the second ratchet wheel, and rotated in the same direction, to tension the spring, the spring load being maintained by the second ratchet wheel pawl. This earlier arrangement suffered from the disadvantages that the spring was of such low tension that it could wrap about a central shaft, otherwise being substantially unsupported when in a partially tensioned condition; also, in operation it was necessary to relocate the load tommy bar from the first capstan to the second, both for applying the initial loading, and at any subsequent re-checking of cable tension. Also, both capstans were loaded in the same rotational direction  
           [0016]    For unloading of the cable it was necessary to first insert the tommy bar in the second capstan, to further tension the spring and enable disengagement of the associated ratchet pawl; then release the ratchet pawl and ease back on the tommy bar so as to dissipate the tension in the spring; the tommy bar being then relocated in the first capstan, the pawl released, and the cable or chain detensioned with the tommy bar, under control, and then released.  
           [0017]    The limited spring support provision of Arbogast&#39;s central shaft provided virtually no inherent load limitation, so that in view of the spring&#39;s evident low stiffness, the spring could be readily over-tensioned and suffer permanent deformation. Also, the spring required several leverings with the tommy bar in order to apply sufficient tension to it. This and earlier attempts appear to have been unsuccessful, as the problem of loss in tension in load hold-down members has remained, leading to the above-mentioned proposed legislative solution.  
         SUMMARY OF THE INVENTION  
         [0018]    The present invention has a number of embodiments, which are applicable to OEM equipment and also provide retro-fit improvements to prior-existing load restraint winch systems, as used for securing an elongated load hold-down member such as a load strap in secured, tensioned relation.  
           [0019]    The winch systems presently in widespread use generally comprise a winch having a rotatable drum; manually operated torque-applying capstan means for rotating the drum to wind-on and apply load-securing tension to the hold-down member; and ratchet means to prevent over-hauling of the drum by the tensioned hold-down member. The winch drums frequently comprise a slotted cylinder, through which slots a load strap can be threaded. Other winch drums may comprise a squirrel cage comprised of three or more parallel bars, through and about which the load strap or other member is threaded and wound.  
           [0020]    The retro-fit improvement embodiment for existing winches consists of spring-loaded tensioning means, for external attachment to the prior winch in torque-transfer relation therewith, the spring-loaded tensioning means being attached in releasably secured relation, to the existing winch capstan means, leaving undisturbed the original winch ratchet.  
           [0021]    A ratchet wheel and ratchet pawl portion of the attached spring loaded tensioning means provides selective coupling of the tensioning spring to the winch drum in torque-transfer relation therewith, to drive the drum in tension-maintaining relation with the hold-down member.  
           [0022]    The attachable embodiment has a mounting cylinder that axially telescopes with the capstan portion of an existing winch, the mounting cylinder being pinned in place by way of a shear pin that engages the tommy bar holes of the capstan, thus locking the cylinder and original capstan together in torque transfer relation.  
           [0023]    A retainer cylinder, slid over the mounting cylinder may be used to retain the shear pin in place.  
           [0024]    A spring assembly is rotatably mounted substantially coaxial with the mounting cylinder, and may serve as an alternative to the retainer cylinder to trap the shear pin against withdrawal.  
           [0025]    The spring assembly has a barrel portion that slides in rotatable relation over the mounting cylinder, or the retainer, whichever is radially outermost. The barrel portion has the helical torsion spring loosely mounted thereon.  
           [0026]    A lobed end plate secured to the outer end of the barrel carries a bracket by which the spring outer end is secured to the end plate. The spring inner end is removably attached to the adjacent outer end face of the winch frame, by way of an angled bracket welded to the face of the frame, to form a retention aperture.  
           [0027]    The barrel preferably has an outwardly extending loading bracket with an offset capstan hole, by means of which the barrel can be rotated, using a standard tommy bar, pulling in an upward direction  
           [0028]    The bracket is sized and located for upward rotation by way of a tommy bar, for approximately 170 ??? degrees rotation of the barrel and of the spring outer end, whereat the bracket comes into blocking engagement with the track on which the winch is mounted, thereby limiting the loading of the spring to about 170 degrees of rotation. The stiffness of the spring is such that with a three foot long tommy bar, this degree of spring torque loading requires a lifting force of about 120 lbs applied to the tommy bar The lobed end plate also carries a ratchet pawl pivotally suspended from the outer side of the end plate. The loading bracket is mounted on the inner side of the end plate lobe. The ratchet pawl, which is suspended from the lobe portion of the barrel end plate, can pivot radially inwardly, automatically under its own weight, into ratcheting engagement with the capstan ratchet wheel when the tommy bar is engaged, and the end plate rotated through about 160 degrees.  
           [0029]    In use, with the end plate ratchet pawl hanging clear of the ratchet wheel, the capstan can be used in the same fashion as was the original capstan, to take up and tension the load belt, or to enable the releasing of the winch original ratchet. Such take-up and tensioning of the load strap is obtained by downward movement of the tommy bar.  
           [0030]    Relocation of the loading tommy bar into the loading bracket, and with as much as about a half-turn upward rotation of the bar, serves to tension the spring to as much as about 360 pounds-feet, while also causing the ratchet pawl to swing under its own weight into ratcheting engagement with the capstan/ratchet wheel.  
           [0031]    This serves to lock-in the applied torque, which is simultaneously applied to the spring, to the capstan/ratchet wheel, and thus, to the winch, being applied to the winch in a direction to sustain the loading of the load strap. Thus, in the event of load movement that leads to a reduction in tension in the load strap, the spring load will come into play, to maintain the strap load and immediately counter the tendency of the strap to slacken.  
           [0032]    When the spring is initially loaded, the total load applied by the winch to the load strap may then be significantly increased from its usual manual-loading limit of about 600 pound-feet to upward of 1000 pounds-feet, utilizing the available torque provided by the spring as a booster, to enhance a further downward loading applied by the tommy bar to either the capstan, or the barrel, in the normal manual-loading fashion.  
           [0033]    Used in this fashion, the load applied to the load restraining strap is “pumped” up to a significantly higher value, in the order of about 160% of that usually achievable by unassisted manual loading.  
           [0034]    In use, with the spring-loaded tensioning means resiliently loaded and coupled by way of the ratchet wheel and pawl to the winch drum, upon diminishment of the load-securing tension in the load strap to a value less than the available spring force, the spring-loaded tensioning means operates to rotate the winch drum, to maintain the load strap in a tensioned condition.  
           [0035]    Thus, in the subject improved load restraint system the spring-loaded tensioning means includes coupling means that are attached in torque-transfer relation with the drum of an existing winch to enable the connection of the spring-loaded tensioning means with the rotatable drum, in torque transferring relation therewith.  
           [0036]    In the present invention, for an OEM spring-loaded winch or for a reworked winch, where the original winch drum is journaled in the end frame member of the winch adjacent its capstan, the bore in the frame end plate is enlarged sufficiently to accept entry therethrough of the spring barrel, thus reinforcing the winch drum against the increased bending moment loads that arise as a consequence of the increased overhang associated with the outboard attachment of the spring system.  
           [0037]    An annular shoulder or “stop-washer” secured about the winch drum serves to limit the penetration of the spring barrel into the drum space.  
           [0038]    The winch ratchet and pawl arrangement also is strengthened to meet the greater loads that can now be applied by the winch, which loads are of course also applied to the structure of the winch. Thus, a ratchet pawl spring is provided, to maintain the ratchet in engaged relation with the ratchet wheel.  
           [0039]    Also provided is a ratchet clip which is removably mounted on the winch end frame and can be relocated in locking relation with the ratchet pawl to hold the ratchet pawl in either a downward, engaged position, or in an upward, disengaged position.  
           [0040]    A further provision is a dual ratchet wheel having a pair of 6-tooth ratchet wheels in place of the usual 12-tooth ratchet wheel, the teeth of the twin wheels being in mutually off-set relation, so as to provide the tooth pitch effect of a 12-tooth ratchet wheel, but with the greater tooth strength that a 6-tooth wheel makes possible.  
           [0041]    The subject spring-loaded tensioning means may include low-friction support bearings for the rotational parts.  
           [0042]    In the subject embodiment, when installed, the spring free end is secured against rotation by way of attachment to the adjoining capstan frame. A cranked plate having its ends welded to the adjacent outside face of the capstan frame forms a recess to receive the spring end in inserted, withdrawable relation.  
           [0043]    In using these embodiments, the automatic ratchet pawl engagement of the added gravity-positioned pawl has the particular advantage that an operator/trucker can retain both hands upon the lever/tommy bar when applying torsion loading to the spring. Stiff springs are used, such that for approximately one half turn of the spring, a torque of up to about 360 pounds-feet is generated. This can impart up to about six to eight inches of tightening displacement to a load strap, while retaining considerable tension upon that strap. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0044]    Certain embodiments of the invention are described by way of illustration, without limitation thereto other than as set forth in the accompanying claims, reference being made to the accompanying drawings, wherein:  
         [0045]    [0045]FIG. 1 is an end perspective view showing a portion of a standard type of truck winch, together with the elements of one embodiment of the present invention in exploded, disassembled relation;  
         [0046]    [0046]FIG. 1A is a side view of the truck winch of FIG. 1 in assembled relation;  
         [0047]    [0047]FIG. 2 is a perspective view of a winch ratchet wheel with a spring-loaded pawl;  
         [0048]    [0048]FIG. 2A is a perspective view of the pawl spring of FIG. 2  
         [0049]    [0049]FIG. 3 is an end elevation of a subject winch with a dual ratchet wheel and spring-loaded pawls;  
         [0050]    [0050]FIG. 3A is a perspective view of a safety clip embodiment of the present invention;  
         [0051]    [0051]FIG. 4A shows the safety clip of FIG. 3A applied in locking relation with the dual pawls of FIG. 3;  
         [0052]    [0052]FIG. 4B shows the safety clip of FIG. 3A applied in deactivating relation with the pawls of FIG. 3. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0053]    Referring to FIG. 1, a portion of a winch  10  is shown, having a top frame member  12 , a frame end member  14 , and a drum  16 , with a capstan  18  projecting from the member  14 , to which capstan  18  the safety adaptation kit  20  in accordance with the present invention is mounted. The capstan  18  has four bar apertures  19  that normally receive the tapered toe of a trucker&#39;s loading bar (not shown), known as a “tommy” bar.  
         [0054]    In the case of an OEM or a reworked winch embodiment, the recess in the winch endplate  14 , through which the capstan  18  protrudes, is bored out to a predetermined greater diameter, giving a radial clearance from the drum  16 /capstan  18 , as shown.  
         [0055]    The kit  20  has a mounting barrel  22  with a first diametrical aperture  23  that matches a pair of the apertures  19  of the capstan  18 . With the mounting barrel  22  positioned on the capstan  18 , a cylindrical mounting pin  24  can be inserted through the respective aligned apertures  23 ,  19 ,  19 ,  23  of the barrel  22  and capstan  18 , to securely mount the barrel  22  upon the capstan  18 .  
         [0056]    In the case of the OEM and refitted embodiments, an extended left-hand portion of the barrel  22  is entered through the enlarged bore in the endplate  14 , to provide enhanced resistance to the increase in bending moments applied by the overhung safety kit  20 . The barrel  22  has a second diametrical aperture  25  at its outer end.  
         [0057]    A pin retaining cylinder  26  is then slid over the barrel  22 , to trap the mounting pin  24  in secured relation in the capstan  18  and barrel  22 .  
         [0058]    A torsion spring  30  is then slid over the barrel  22 , and a protruding inboard end  32  of the spring  30  is secured to the winch end frame member  14  by way of a bracket  34 , which is welded to the frame end member  14 .  
         [0059]    A rotator cuff  36  (see also FIG. 2), is inserted over the barrel  22 , being entered in supporting relation within the outer coil of spring  30 , with an outer tang end portion  31  of the spring  30  being inserted axially into a bushing  38  that forms a part of the rotator cuff  36 . The cuff  36  has a diametrical access aperture  37 , through which a spring pin  44  can be passed for securing in locked relation the aligned apertures of other component parts.  
         [0060]    A capstan  40  with an integral ratchet wheel  42  is inserted into the outer end of the barrel  22 , having a diametrical inner aperture  43  of capstan  40  aligned with aperture  25  of the barrel  22 , and with a diametrical access aperture  37  of the rotator cuff  36 .  
         [0061]    The spring pin  44  is inserted through and past the aligned diametrical access aperture  37  of the cuff  36 , into engaging relation with the apertures  25 , and  43  of the barrel  22  and capstan  40  respectively, which serves to secure the barrel  22  and capstan  40  in mutual rotational and torque transfer relation, independently of rotator cuff  36 .  
         [0062]    The spring pin  44  has a length that is less than the inner diameter of the cuff  36 , being located so as not to make contact with the cuff  36  or impede the free rotation of cuff  36  upon the barrel  22 .  
         [0063]    Referring to FIG. 1A, this shows the subject elements of FIG. 1 in assembled relation, ready for use in securing a pull-down load on trucks, flat beds and the like.  
         [0064]    The inward axial displacement of the barrel  22  along the drum  16  is limited by an annular shoulder or “stop-washer”  19  secured about the winch drum.  
         [0065]    The drum  16  is manually driven by capstan assembly  14 , by means of a lever or tommy-bar in the usual pull-down fashion.  
         [0066]    Such tommy bars are usually about 3-feet long, enabling a 200-pound trucker to pull down a torque of about 600 lbs-feet on to the winch. A ratchet wheel and pawl assembly  11 , illustrated as being located at the left-hand side of the winch  10 , prevent overhauling of the winch  10  by the load strap (not shown) that is threaded through the drum slot  17 , and wrapped about the drum  16 .  
         [0067]    Downward motion of the tommy bar when located in the capstan  47  serves to wind excess load strap onto the drum  16 , and to tension the load strap.  
         [0068]    The ratchet pawl  52  is suspended from the barrel end plate  44  such that it can pivot under its own weight when in the raised (12-oclock) position into ratcheting engagement with the capstan ratchet wheel  58 .  
         [0069]    In use, with the spring  30  untensioned, and the end plate ratchet pawl  52  hanging clear of the ratchet wheel  42 , the capstan  47  can be used in the same fashion as was the original capstan  18 , to rotate the winch drum  14  and take up and tension the load belt, which is secured by the winch original ratchet  11 , shown in FIG. 1A.  
         [0070]    Wind-on and tensioning of the load strap is provided by downward movement of the tommy bar.  
         [0071]    Relocation of the tommy bar  20  into the barrel capstan hole  50 , with an upward half-turn rotation of the bar, serves to tension the spring  30  to as much as about 400 lbs feet, while causing the ratchet pawl  52  to swing under gravity into ratcheting engagement with the capstan/ratchet wheel  58 .  
         [0072]    This serves to lock the torqued spring  30  to the capstan/ratchet wheel, and thus, to the winch drum  16 , with the spring tension acting in the direction to sustain the load applied to the load strap.  
         [0073]    To release the load applied to the hold-down member, the load on the capstan  47  is increased sufficiently to permit retraction of the pawl  52  from engagement with the ratchet wheel  58 .  
         [0074]    The spring tension can then be released under control of the tommy bar, moving downwardly.  
         [0075]    The winch drum ratchet  11  can then be released, in usual fashion.  
         [0076]    In operation, in the event that the load settles, such as to normally cause slackening of the load strap or other load hold-down member, the torque applied by the spring  30  will cause the winch to rotate and maintain tension in the load strap, so that slack is unlikely to occur, and the slackening effect upon the load strap of load settlement is at least partially compensated for.  
         [0077]    In a typical instance, the spring can take up of as much as several inches of the hold-down strap, while maintaining the strap under tension.  
         [0078]    The available spring tension, as applied to the load strap, diminishes progressively, as take-up occurs.  
         [0079]    Overhauling of the system is prevented by the operation of the winch ratchet  11 , which contains excessive loads that may be applied to the hold-down strap, due to motion of the vehicle.  
         [0080]    Turning to FIG. 2, the ratchet  11 ′ has a ratchet spring  60  in downward pressing relation on the ratchet pawl  13 , to maintain the ratchet in positive engaged relation despite load surges that can unload the ratchet, and upward forces acting on the pawl as a consequence of vehicular motion which otherwise could disengage the ratchet.  
         [0081]    Turning to FIG. 2A, the pawl spring  60  has a coil  62 , with an extended side arm portion  64  to engage the pawl  13 , and a short, axially extending anchor portion  66 , the end of which can be seen in FIG. 2.  
         [0082]    Turning to FIG. 3, a composite, twin ratchet wheel  70  is shown, the ratchet teeth of the two wheels being mutually offset by 30 degrees, so as to collectively provide a ratcheting interval of thirty degrees, equivalent to a 12-tooth ratchet wheel, but possessing significantly enhanced tooth strength.  
         [0083]    Referring to FIG. 3A, a safety ratchet clip  80  of spring steel has a U-shaped clip portion  82 , with an out-turned toe portion  83 , to facilitate applying the clip  80  to the winch endplate  14 , as shown in FIGS. 4A and 4B. The clip  80  has an axially projecting side-bar portion  84 , to engage the ratchet pawls  13 ′, holding them downwardly in a locked, engaged condition (FIG. 4A), or upwardly in a locked, disengaged condition (FIG. 4B).