WO2005087540A1

WO2005087540A1 - Load restraining apparatus

Info

Publication number: WO2005087540A1
Application number: PCT/AU2005/000335
Authority: WO
Inventors: Maurice John Matthews
Original assignee: Matthews International Pty Ltd
Priority date: 2004-03-11
Filing date: 2005-03-11
Publication date: 2005-09-22

Abstract

Load restraining apparatus (10) including an elongated hollow beam (12) and a flexible load restraining element in the form of a chain (11) extending along the beam (12), the chain (11) passing around rollers (14) at each end of the beam (12) and passing into the beam (12). The chain (11) may passed around a load (38) supported on the beam (12) and an actuators are provided in the beam (12) to draw the chain (11) into the beam (12) to tension the chain (11) around the load (38). The beam (12) may be incorporated in the tray of a load carrying vehicle. In other embodiments, the load restraining element is in the form of a webbing belt.

Description

LOAD RESTRAINING APPARATUS Technical Field This invention relates to load resfraining apparatus which has particular but not exclusive application to restraining loads on vehicles. Background Art A number of different aττa.τιgement are used for restraining loads on vehicles. In the case of heavy vehicles, loads are often restrained by webbing straps, chains or other similar resfraining devices. Generally, h.θwever, difficulties are encountered in ensuring that the load is effectively and sufficiently secured to the vehicle. Where chains are used to tie down the load, it is necessary to provide some means for tensioning the chain. Tensioning is usually carried by means of a chain dog which uses an over-centre principle for tensioning. These devices have a number of disadvantages and in particular the devices can recoil whilst tensioning thereby creating a safety danger. In the case of webbing tie-down devices, webbing having hooks at each end is placed over the load and a ratchiet-type tensioning device is provided or tensioning the webbing over the load. For effective use of this device, strategic anchor points are required on the vehicle close to, or as near as possible to the load. In most instances this is not the case and the tie-down passes over many surfaces, some having sharp edges and comers causing abrasive action and creating high friction contact areas, resulting; in inefficient tensioning and/or tie-down failure . Vehicles are commonly provided with load carrying racks upon which a load may be carried. Generally, the load i s tied down to the racks by ropes or similar tie devices however the problem of safely and effectively securing a load requires the person to be competent in the basics of rigging:, or at least have the ability to tie secure knots. With the increasing number of load carrying utilities and trucks sharing the highways with the general public, this is a very dangerous situation with the potential of cavzsing a serious accident with devastating conseq-uences. The use of other unsuitable materials such as electrical cable, adhesive tape and the like, to tie down the load because of the unavailability of a suitable rope, webbing or chain at the pick-up loading site, further adds to this serious problem. In the building industry where utilities and other similar vehicles are commonly used for transporting building materials which are supported on overhead τac-^"k$ fitted to the vehicle. Overhead racks are typically built to a simple "H" frame design w th little or no binding anchor points, and in most cases no facility for the insertion of an isolation element, such as a timber or synthetic fillet between the material and the racks' metal load-carrying members to increase friction and control of the load, Summary of the Invention The present invention aims to overcome or alleviate the above disadvantages or at least provide an alternative to the known load restraining apparatus by providing apparatus for restraining loads which enables loads to be restrained in a reliable and effective manner. The present invention provides in a first preferred aspect, load restraining apparatus including housing, a flexible load restraining clement extending into said housing, tensioning means within said housing and adapted to be coupled to said load restraining element for application of tension to said load restraining element to restrain a load, said tensioning means including means for engaging an intermediate portion of said element, and means for selectively actuating said tensioning means to draw said load restraining element into said housin . In a preferred form, the load restraining element comprises a chain. Preferably the means for tensioriing the clement comprises an actuator adapted to cooperate with a selected link of the chain. The actuator suitably has a head for cooperation with the selected link or link. The head suitably includes an opening through which the chain may pass. The opening is suitably formed such that in a first position of the chain in the opening, the chain can move freely through the opening and in a second position, the chain is captured against movement through the opening whereby actuation of the actuator in the second position of the chain causes said chain to be drawn into the housing. The opening suitably comprises a keyhole-shaped opening having a slot-like portion in which a chain link can be captured against movement in the second position. The opening also suitable has and enlarged portion through which the chain may pass in the first position. Preferably the head in one attitude cooperates with a chain stripper or stop to urge the chain into the first position. In the first position, the chain may be withdrawn from the housing and attached to a load, applied about a load or attached to a further load restraining element which passes about the load. Guide means are suitably provided to guide the head to its one attitude, The guide means may define a tapering throat. Preferably opposite guide surfaces are provided to define the throat. The opposite guide surface preferably are defined by cam members. The actuator head may include means for cooperation with the guide surfaces. Such means may comprise cam followers. The cam followers may comprise rollers on opposite sides of the head. The chain may extend between a pair of opposite actuating means associated with respective spaced housings whereby the chain may be tensioned or tightened from each end. Suitably each actuating means is located at opposite ends of an elongated beam or member which defines the housings. In another embodiment, the chain at each end of the beam may be adapted tor coupling to a further chain or load restraining element. In this embodiment one end of the chain may be coupled to a spring or the like to apply a pretension to the chain which is maintained in the chain when the actuator draws the chain into the beam to effect further tensioning or tightening of the chain and load restraining element coupled thereto. The actuator suitably comprises a linear actuator. Most preferably the actuator comprises a fluid actuator such as a hydraulic ram, The actuator in this form has a piston rod and the head of the actuator is secured to the piston rod. In a further embodiment, the chain may be drawn into the housing or beam by means of a rotatable drive wheel adapted to cooperate with the chain. The drive wheel suitably comprises a gypsy wheel. The drive wheel may be coupled to a worm drive. The worm drive suitably includes a drive shaft coupled to the wheel. A suitable tool may be selectively coupled to the drive shaft for applying drive suitably manually to the wheel directly. The worm drive suitably also includes a further shaft for driving the drive shaft through a worm/pinion transmission. Preferably the further shaft carries a worm and the drive shaft carries a pinion. The worm of the further shaft may be selectively coupled with the pinion. Suitably the further shaft is supported for axial movement between a first disengaged position where the worm is disengaged from the pinion and a second position where the worm is engaged with the pinion. Suitably biasing means are provided for normally urging the further shaft to the disengaged position. The drive wheel may also cooperate with a further wheel to form a nip through which the chain may pass. Preferably in this embodiment, additional tensioning means may be provided to pretension the chain. The additional tensioning means may comprise a tension spring in the housing secured to an end of the chain. Alternatively the tension spring may be secured to a roller assembly around which the chain passes. The present invention in a further preferred aspect provides load restraining apparatus comprising spaced apart tensioning means adapted to be coupled at spaced positions to an elongated flexible load restraining element for application of tension to said load restraining element to restrain a load and means for selectively actuating each said tensioning means. Suitably the tensioning means is provided at or adjacent each end of an elongated frame member or beam. In one preferred form, the load restraining element comprises a strap such as a webbing strap which normally extends between and is coupled at each end to the respective tensioning means. The tensioning means are suitably arranged within a housing or housings or a beam or other elongated member at each end thereof. The tensionin means suitably comprise means for winding in the strap. Such means may comprise winch means. The winch means suitably comprises spaced apart means about which the strap may be wound. The spaced apart means may comprise a pair of rotatable means and means are proved to couple the rotatable means such that both rotatable means may rotate simultaneously. Suitably one of the rotatable means is a driving means and the other of the rotatable means is driven through the coupling means by the driving means. The rotatable means may comprise rollers and the coupling means may comprise an endless belt or other endless coupling means which passes around the rollers. Means may be provided for connecting the strap to the belt or other coupling means for movement therewith. One of the rollers suitably comprises a roller which can be driven to transmit drive through the belt to the other roller to effect rotation thereof. In a particularly preferred form, the rotatable means comprise one or more sprockets and the coupling means comprises one or more endless chains wound about the one or more sprockets. Suitably, means are provided for connecting the strap to the one or more endless chains for movement therewith. Suitably the connecting means comprise a transverse connecting pin at an inner end of the strap. The chain or chains may carry one or. more hooks for engagement with the connecting pin. A guide member may be provided around the one or more sprockets to separate the strap from the sprockets and chain or chains. One of the sprockets may comprise a drive sprocket which when driven causes through the chain or chains rotation of the other sprocket. The beam suitably includes idler rollers at each end around which the strap may pass. In one embodiment, the means for driving the drive sprocket or roller comprise a worm drive. The worm drive may be of the above described type and include a drive shaft coupled to the drive sprocket or roller such that the sprocket or roller can be driven directly or through a worm pinion transmission . In all of the above embodiments, anchor roller assemblies may be associated with the beam beneath which the load restraining strap or element may be passed. The anchor roller assemblies may be engaged with the beam at a selected positions along the beam. The roller assemblies may include hooked anns for engagement with transverse pins provided at spaced locations along the beam. Spring loaded retaining means may be provided to retain the roller assemblies to a selected transverse pin. Whilst the winch means described above however is particularly suited for use in the described load restraining applications, it may be used in many different applications where a winching function is required separate from a beam or other elongated member, In a further embodiment the or each tensioning means is adapted to tension or apply a force to an elongated flexible element which may be coupled to the load restraining element. Thus the strap associated with the winch means may be releasably coupled to a load restraining element. In yet a further embodiment, the tensioning means may comprise means for gripping the strap and moving the gripped strap to tension the strap. The gripping means may comprise first and second jaws between which the strap may be gripped. Means are suitably provided for moving the jaws towards each other to enable gripping of the strap. One of the jaws may be moved by suitably actuating means. The actuating means may comprise a fluid actuator such as an hydraulic piston and cylinder actuator or other linear ac utator. Preferably the one jaw includes reeving means through which the strap may be passed. Preferably, actuation of the actuator causes rotation of the one jaw and wrapping of the strap at least part way therearound for clamping against the other jaw. Preferably the jaw is rotated through a rack and pinion transmission. The pinion is suitably rotatable with the one jaw. The one jaw is suitably mounted for rotation on a first bracket fixed for movement with the actuating means. The rack is suitably fixed for movement with a second bracket which is biased away from the first bracket and towards the one jaw. The biasing means suitably comprises one or more springs. The other jaw is suitably arranged for sliding movement relative to the first and second brackets. Biasing means are suitably provided for biasing the other jaw away from the second bracket and towards the one jaw. In yet a further embodiment, the load restraining apparatus may be incorporated in a load carrying rack to be carried by or mounted on a vehicle. The load carrying rack suitably comprises an elongated load carrying member or beam and winch assemblies at opposite ends of the membe or beam, Suitably the load carrying member or beam is adapted to be supported by any suitably frame or mounting arrangement to a vehicle. The frame may include spaced apart upright arms. Preferably, the winch assemblies include housings and the housings ate adapted to be mounted to respective spaced upright arms. ■ In a particularly preferred form, the frames are of a U-shaped configuration and a pair of such frames are provided for supporting front and rear load carrying racks. The U- shaped frames suitably have a pair of spaced upright arms for supporting corresponding ends of front and rear load carrying racks. The U-shaped frame also suitably includes a leg joining the arms which is disposed substantially hori2ontally in use and suitably secured to upper edges of the side walls of a pick-up type vehicle. Where the load carrying racks are to be supported on a tray back vehicle, the tray of the vehicle may have a plurality of upright struts mounted thereto to support at their upper ends a respective end of a load carrying rack. Suitably mounting means are provided to permit the struts to be positioned at a series of positions longitudinally of the tray. The mounting means may comprise a mounting strap having spaced locating means therealong with which the struts may cooperate. Suitably the struts are provided at their lower ends with one or more hooks for cooperation with the mounting strap. The mounting strap may have a series of spaced slots or apertures for receipt of the one or more hooks. One of the hooks may be adjustable to clamp onto or capture the mounting strap through the slot or aperture. Brief Description of the Drawings In order that the invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate preferred embodiments of the invention and wherein :- Fig. 1 illustrates an embodiment of load restraining apparatus according to the invention restrairώ g a load; Fig. 2 is a cut away view from one side of the hydraulic chain tensioning mechanism of the apparatus of Fig. 1; Fig. 3 is a further side partly cut away view of the chain tensioning mechanism; Fig. 4 illustrates the chain gripping head of the hydraulic tensioning actuator; Fig. 5 illustrates the chain anchor roller assembly for use with the load restraining apparatus of Fig. 1; Figs. 6 and 7 are opposite views illustrating the manner in which the chain is engaged by the chain gripping head; Fig. 8 illustrates a further embodiment of load restraining apparatus according to the invention; Fig. 9 and 10 are cut-away views from one side of the hydraulic chain tensioning mechanism of the apparatus of Fig. 8; Fig. 11 illustrates the load restraining apparatus of Fig. 8 incorporated in a deck or tray of a load carrying vehicle; Fig. 12 illustrates portion or deck of the load carrying vehicle with the chain coupler retracted; Fig. 13 illustrates a cut-away view of one end of a further load restraining apparatus according to the invention; Fig. 14 is a view of the idler roller assemblies of the apparatus of Fig. 13 at the ends of the load carrying beam; Fig. 15 is an opposite side cut-away view of the apparatus of Fig. 13; Fig. 16 illustrates a worm drive for use in actuating the load restraint apparatus of Figs. 13 to 15; Fig.17 illustrates in perspective view load restraining apparatus according to a further embodiment of the invention and incorporated in the tray of a vehicle; Fig. IS is a cutaway view showing the configuration of one of the winch assemblies of the load restraining apparatus of Fig. 17; Figs, 1 and 20 are cut away views of a worm drive for driving the winch assembly of Fig. 18 in an engaged and disengaged attitude respectively; Fig. 21 illustrates in perspective view an anchor roller assembly for use with the load restraining apparatus of Fig. 17; Fig. 22 illustrates a typical manner in which the load restraining apparatus of Fig. 17 is employed; Figs. 23 and 24 are perspective views of a winch assembly of the type used in the load restraining apparatus of Fig. 17; Fig. 25 illustrates portion of an alternative webbing strap tensioning apparatus according to another embodiment of the invention; Figs, 26 to 30 illustrated the operation of the tensioning apparatus of Fig. 25; Fig. 31 illustrates a further embodiment of load restraining apparatus according to the invention incorporated in a load carrying rack; Fig. 32 is an enlarged end view of the rack of Fig. 31; Fig. 33 is an exploded view of one end of the rack of Fig. 31; Fig. 34 is an enlarged view of an end of the load carrying beam of the rack showing the manner in which the arm for securing the anchor roller assemblies is engaged with the load carrying beam; Fig. 35 illustrates the manner in which loads are supported and secured on the load carrying rack of Figs. 31 and 32; Figs. 36 and 37 are opposite views illustrating the load carrying rack applied to a vehicle; Fig. 38 illustrates a pair of spaced frames for mounting of the load carrying racks; Fig. 39 illustrates in exploded view, the manner in which the load carrying racks are supported on the frames of Fig. 38; Fig. 40 illustrates the manner in which the frames of Fig. 38 are mounted to the side walls of the vehicle of Figs. 36 and 37; Fig. 41 illustrates a further arrangement for supporting the load carrying racks to a vehicle; Fig. 42 is an enlarged view of a mounting strip of the arrangement of Fig. 41; Fig. 43 i$ an enlarged view showing a lower portion of a strut for supporting a load carrying rack engaged with a mounting strip; and Figs. 44 to 46 illustrate the manner in which the strut is engaged with the mounting strip. Detailed Description of the Preferred Embodiments Referring firstly to Figs. 1 to 6, there is illustrated a first embodiment of load restraint apparatus 10 according to the invention for incorporation in the deck of a load carrying vehicle. Alternatively, the apparatLis 10 may be used in a vertical attitude for example for incorporation in a logging-type staunchion/bolster. The apparatus 10 uses a chain 11 as the load restraining member for location over or around a load and includes elongated hollow load carrying beam 12 which houses at each end chain tensioning mechanisms 13. Gypsy-like guide rollers 14 are provided at each end of the beam 12 around which the chain 11 passes and a hollow housing 15 is provided at each end of the beam 12 to collect -unused chain 11 on the lower side of the rollers 14. The housing 1 has a lower surface or base 16 which is inclined downwardly from the outer end of the beam 12 so as to be of maximum depth at its inner end. Chain 1 1 passing into the housing 15 is directed by the inclined lower surface 16 towards the maximum depth of the housing 15 such that a maximum length of chain 11 can be accommodated in the housing 15. Each chain tensioning mechanism 13 as illustrated in Figs. 2 and 3 includes an hydraulic actuator 17 having its cylinder 18 secured by a pivot pin 19 to the beam 12. A chain gripping head 20 is fixed to the end of the piston rod 21 of the actuator 17. The gripping head 20 is provided with a keyhole-shaped opening 22 through which the chain 11 passes from the roller 14 into the housing 15 through a slot 23 in a lower flange of the beam 12. A pair of chain link receiving slots 24 extend from the opening 22 to the free end of the gripping head 20. The gripping head 20 is further provided on opposite sides with rollers 25 which extend transversely relative to the piston rod 21 and longitudinal axis of the head 20 for guiding movement of the gripping head 20 in the manner described further below. The rollers 25 suitably comprise roller bearings. Provided within the beam 12 are upper and lower pairs of cam-like guides 26 and 27 between which the rollers 25 of the chain gripping head 20 are guided. As illustrated, the rear ends of the guides 26 and 27 adjacent the actuator 17 are angled inwardly towards each other to define a tapering throat 28 which guides the rollers 25 between the guides 26 and 27. Chain strippers 29 in the form of stop plates are provided adjacent the outer ends of the beam 12. When the hydraulic actuator 17 is actuated to extend the piston rod 21. the chain gripping head 20 is moved to a position overlying the chain stripper 29. In this position, the chain stripper 29 acting as a stop engages with a link 30 of a chain 11 located in the keyhole opening 22 to move it into the larger cross sectional area of the opening 22 thereby permitting the chain 11 to be freely pulled out of the housing 15. An angled shoe 1 is provided adjacent the roller 14 to maintain the chain 1 X in contact with the roller 14. The load restraining apparatus 10 also may include anchor roller assemblies 32 (see

Fig. 5) which have rollers 33 of a gypsy-like configuration shaped for engagement with the chain 11. The roller assemblies 32 are spring loaded so as to be capable of engaging with a selected one of a series of transverse retaining pins 34 provided at spaced locations along the beam 12 as shown in Fig. 2. For this purpose, slidable spring loaded abutment members 35 are mounted on the opposite arms 36 for engagement with the top of the beam 12 so that the hooks 37 of the arms 36 maintain engagement with the pins 34. The roller assemblies 32 can be detached by applying a downward force to move the hooks 37 against the bias of the spring loaded abutment members 35 to free the hooks 37 from the pins 34. The apparatus 10 may be located in the tray of a vehicle to extend transversely of the vehicle tray as an under-deck mounted apparatus for all rigid trucks and semi-trailers. The beam 12 of the apparatus 10 is thus located flush with the upper surfaces of longitudinally extending beams of the truck or trailer deck and extends normal to the beams. To restrain a load 38 in this case lengths of timber, the load 38 is supported on the upper surface of the beam 12 and the chain 11 is withdrawn from the housings 15 at opposite ends of the beam 12 so that it can be looped over the load 38. Anchor roller assemblies 32 can then be positioned on opposite sides of the load 38 and engaged with the transverse retaining pins 34 of the beam 12 to guide the chain 11 from the ends of the beam 12 to a position adjacent the opposite sides of the load 38 and up over the load 38. The respective actuators 17 may then be actuated to retract the piston rods 21 and the gripping heads 20 either simultaneously or independently. As the gripping heads 20 are moved away from the chain strippers 99, the chain link 30 in the keyhole opening 22 will move into the smaller slot shaped portion of the opening 22. In this position, the links on opposite sides of the link 30 within the opening 22 can no longer pass through the opening 22. As the piston rod 21 is continued to be retracted, the chain 11 is thus gripped and pulled into the end of the beam 12 around the roller 14. The chain 11 will thus be tensioned around the load 38. When sufficient restraining tension has been achieved, the actuator 17 may cease actuation. Of course, only one actuator 17 needs to be actuated to tension the chain 11 provided that the other actuator 17 has been actuated to an extent to move the gripping head 20 away from the chain stripper 29 so that the chain 12 is anchored at its opposite end. When it is desired to release the load 38, the actuator or actuators 17 are actuated to extend the piston rods 21 and heads 20 until they reach the position show in Fig. 3 which will cause the chain link 30 the opening 22 to be moved into the larger portion thereof by abutment with the stripper 29. The chain 11 in this position is released and may be simply pulled from the housings 15 at each end of the beam 12 and be released from the load 38. Referring now to Figs. 8 to 10, there is illustrated a further embodiment of load restraining apparatus 39 according to the invention which is similar to the embodiment of Figs. 1 to 7. The apparatus 39 includes a load carrying beam 40 which as before houses at each end a gypsy-like guide roller 41 around which a chain 42 may pass. The chain 42 also passes around a second gypsy-like guide roller 43 located in a housing 44 on the underside of the beam 40. One end of the chain 42 is connected to a spring 45 which passes through a slot 46 in a lower flange of the beam 12 and which is anchored to a lug 47 within the beam 12. The opposite end of the chain 42 is provided with a chain coupler 48 which usually is located above the beam 12 (see Fig. 8). A hydraulic actuator 49 is also secured to the lug 47 and the piston rod 50 of the actuator 49 tei inates in a chain gripping head 51 which is similar to the head 20 of Fig. 4. The chain 42 passes through a keyhole-shaped opening 52 in the head 20 and the head 20 is adapted to cooperate with a chain stripper 53 at the outer end of the beam 40. A.s in the embodiment of Figs. 1 to 4, the gripping head 51 is provided with opposite rollers 5 such as roller bearings which are adapted to cooperate with lower and upper caroming guides 55 and 56 which guide the gripping head 51 into position in register with the chain, stripper 53. Further as in the embodiment of Figs. 1 to 3, anchor roller assemblies 57 which are of the same configuration as the roller assemblies 32 can be used with the apparatus 39 and engaged with one of a plurality of transverse retaining pins 58 fixed at spaced apart

• positions along the beam 40. The beam 40 also includes a channel 59 in which the chain 42 can at least partially be guided and located. I The load restraining apparatus 3 may be incorporated in the deck 60 of a load carrying vehicle to lie substantially flush therewith as shown in Fig. 11. Anchor roller assemblies 57 may be positioned along the beam 40 where required. If necessary slots 61 may be provided at spaced apart positions along the beam 40 to accept the hooks 62 of the anchor roller assemblies 57 to enable them to engage with one of the transverse pins 58. In use, a load to be secured is placed on the beam 40 in a transverse direction thereto and a chain is provided over the load. When the actuator 49 is in the extended position of Fig. 10, the chain 42 is stripped from engagement with the keyhole opening 52 in the head 51 so that the chain 42 can be withdrawn to its maximum extent and passed beneath an anchor roller assembly 57. The chain coupler 48 is then engaged with the chain 42' (shown in dotted outline in Fig. 11) passing over the load. This procedure is repeated at opposite ends of the beam 40. To apply tension to the chain 42 and thus to the chain 42', one or both hydraulic actuators 49 at opposite ends of the beam 40 are retracted. The chain link located within the keyhole opening 52 in the head 51 is prevented from passing through the opening 52 by moving into the smaller slot-like portion thereof such that the section of the chain 42 between the rollers 41 and 43 is pulled into the beam 40. During this movement, the spring 45 will extend and the chain coupler 48 pulled towards the roller 41. The chain 42' which is connected through the coupler 48 to the chain 42 will thus be tensioned over the load. When it is desired to release the tension in the chain 42', the pressure in the actuator

49 is reduced allowing the spring 45 to draw the head 51 back towards the position of Figs. 9 and 10. Alternatively, fluid pressure may be applied to the actuator 49 to extend the piston rod 5O. The couplers 48 may then be detached from the chain 42' which may then be removed from the load. If desired and as shown in Fig. 12, the chain couplers 48 may be fully retracted to the ends of the beam 40 by removing the anchor roller assemblies 57 and retracting the actuators 49. The chain couplers 48 may be retained in the retracted position by engagement with tongues 63 provided on a side frame member of the vehicle tray 60. Referring now to Figs. 13 to 15. there is illustrated a further embodiment of load restraining apparatus 64 according to the invention which is similar in principle to the embodiment of Figs. 8 to 11 except that in this embodiment, an alternative chain tensioning arrangement is provided for tensioning a chain 65 which is equivalent to the chain 42 and includes a chain coupler at its end for coupling to a chain located over a load. As in the previous embodiments the apparatus 64 includes an elongated beam 66 having chain tensioning mechanisms 67 located within and at each end of the beam 66. Each chain tensioning mechanism 67 is operable to wind in the chain 65 which is anchored at 68 at one end within the beam 66. The chain 65 passes around a tensioning roller 69 and back through a nip defined between a gypsy-like drive roller 70 and an opposing nip roller 71. The tensioning roller 69 is supported for rotation in a bracket 72 which is connected by a wire or cable 73 which passes around a fixed guide roller 74 to a tension spring 75 anchored to the beam 66. The spring 75 will thus tend to urge the tensioning roller 69 to the right in Fig. 13 such as to maintain the opposing runs of the chain 63 between the anchor point 68 and the drive roller 70 under tension. The chain 65 passes around the nip roller 70 out of the upper end of the beam 66 such that the free end 76 can be provided with a chain coupler for example of the type 48 shown in Fig. 11. To wind in the chain 65, the drive roller 70 is coupled to a worm drive 77 (see Fig. 16). For this purpose, a drive shaft 78 extends from the drive roller 70 and is provided with a hexagonal head 79 for connection to a complementary tool to enable rotation of the drive roller 70 manually or with the aid of a power tool. A gear 80 is fixed for rotation with the shaft 78 and is coupled to a further gear 81 fixed for rotation with the nip roller 71 such that rotational drive applied through the shaft 78 is transmitted through the intermeshing gears 80 and 81 to the roller 70. The drive shaft 78 may also be provided with a pinion for meshing with a worm fixed to transverse shaft 82 to provide for "fine" rotation or adjustment of the drive wheel 70. The worm drive 77 is more specifically described below with reference to Figs. 19 and 20. The apparatus 64 may be located in or on a load carrying vehicle to extend transversely thereof and preferable recessed within the deck or tray of a vehicle in the same manner as that shown in Fig. 11. Where a load to be secured, a chain is provided over the load and coupled at each end through suitable couplers to the chains 65 at each end of the beam 66. The chain 65 may pass beneath anchor roller assemblies 83 coupled to the beam 66 in the same manner as described with reference to Figs. S to 11. The drive wheel 70 may then be rotatably driven by a suitable tool coupled to the shaft head 79 to rotate the drive wheel 70 in a clockwise direction in Fig. 13. This movement will wind in the chain 65 in the direction of the arrow A in Fig. 13 which through the engagement between the chain 65 and the chain passing around the load, tensions the load restraining chain. Where only fine adjustment of the chain 65 is required, the drive wheel 70 may be driven through the worm shaft 82. During this movement the tensioning roller 69 will through the tension spring 75 and cable 73 maintain tension in the chain runs between the roller 69 and drive wheel 70. When the correct tension is achieved, the drive wheel 70 will be locked in a rotational position through the worm/pinion arrangement to maintain the tension in the chain 65. One or both chain tensioning mechanisms 67 at opposite ends of the beam 66 can be operated in this manner. When it is desired to release the tension in the chain 42 and thus the load holding or restraining chain, the drive wheel 70 may be simply rotated in the opposite direction so that the chain 65 can be wound out in the direction opposite to the direction A. Alternatively, the roller 70 may be unlocked for example by disengaging the worm and pinion and the chain 65 pulled out of the beam 66 against the tension of the spring 75 to enable it to be detached from the load holding chain. It will be appreciated that whilst the apparatus of Figs. 8 to 15 is designed for coupling to a chain such as the chain 42' which passes over a load, the apparatus may be coupled to other elongated flexible restraining members such as wires, cables, ropes or webbing straps. In these cases, the chains associated with the apparatus are provided with alternative coupling means such as hooks or clamps to enable coupling to the restraining member which passes over the load. It will also be appreciated that whilst the apparatuses described above are particularly suited for incorporation in or application to load carrying vehicles and suitably by being recessed in the trays or decks of load carrying vehicles, they may be used in many other applications where a load is to be restrained. Thus the beams 12, 40, and 66 may be oriented in a vertical attitude so that a load may be secured from the side. Referring now to Fig. 17 there is illustrated a further embodiment of load restraining ^' apparatus 84 according to the invention comprising an elongated hollow beam 85 which incorporates winch assemblies 86 at each end between which a webbing load restraining strap 87 extends longitudinally along the upper side of the beam 85. The load restraining apparatus 84 typically and as shown may be incorporated as an under-deck mounted apparatus for all rigid trucks and semi-trailers. The beam 85 of the apparatus 84 is thus located flush with the upper surfaces of longitudinally extending beams 88 of the truck or trailer deck and extend normal to the beams 88. A series of load restraining apparatuses 84 may be located at spaced positions along the beams 88. The beams 88 may be of a U- or channel shaped cross section or fabricated in that configuration to have opposite side flanges 89, Each winch assembly 86 as shown more clearly in Fig. 18 includes a drive shaft 90 which, extends transversely of the beam 85 and which is supported in bearings 1 to opposite side flanges 89 of the beam 88. The shaft 90 carries within the beam 88 a drive sprocket or sprockets 92 which may be keyed to the shaft 90. An idler sprocket or sprockets 93 is/ are keyed to a further idler shaft 94 spaced from and extending parallel to the shaft 90, the shaft 24 also being supported in bearings in a similar manner to the support of the shaft 90. Endless chains 95 are passed around and supported by the respective sprockets 92 and 93. Hooks 96 are fixed to opposite sides of the chains 95 and supported for movement with the chains 95. An elongated guide 97 extends around the spigots 92 and 93 to cover the chain 95 and sprockets 92 and 93. A webbing strap 98 is wound and looped about the guide 97 to form a number of layers. The inner end. of the strap 98 terminates in a cross arm 99 which can be engaged on opposite sides by the respective hooks 96. Rotation applied to the drive shaft 90 and thus sprocket or sprockets 92 in the anticlockwise direction in Fig, 18 will cause movement of the chain/s 97 supported by the respective sprockets 92 and 93 to wind in the webbing strap 98 around the guide 97. The driye shaft 90 extends from a worm drive 100 supported in a housing 101 on one side of the beam 85, the worm drive 1.00 as shown more clearly in Figs. 19 and 20 comprising a pinion 102 connected or keyed to the shaft 90 and a worm 103 adapted for engagement with the pinion 102. The worm 103 is formed or provided on a shaft 104 arranged for longitudinal sliding movement in a guide bore 105 which extends normal to the shaft 90. A spring 105 is provided for normally biasing the shaft 104 outwardly of the housing 101 and thus the onn 1 3 out of engagement with the pinion 102. The outer end of the shaft 104 is provided with a hexagonal head 107 for engagement by a suitable tool. The shaft 90 also terminates in a hexagonal head 108 which may be formed on the shaft 90 or provided as an extension of the shaft 90. "Coarse" rotation of the drive sprocket or sprockets 92 can be_. effected directly by a suitably tool engaged with the hexagonal head 108. For "fine" rotation of the drive sprocket or sprockets 92, a suitable tool is engaged with the hexagonal head 107. At the same time, an axial force is applied to the head 107 to urge the shaft 104 longitudinally from the disengaged position of Fig. 19 to the engaged position of Fig. 20 where the worm 103 is moved into mesh with the pinion 102. Rotation of the tool and thus head 107 transmits rotation to the pinion 102. Access to the head 1 7 is provided by means of an opening 109 formed in a side beam 88" in alignment with the head 107. (see Fig. 17) The webbing strap 87 as shown passes around a guide roller 110 at the end of the beam 85 and along the beam 85 to be coupled to a similar winch assembly 86 and passed around a similar guide roller 110 at the opposite end of the beam 85. A series of anchor roller assemblies HI shown in Fig. 21 may be provided for use with the apparatus 84 for assisting in efficiently securing the load in position. The roller assembly 111 comprise a U-shaped frame, the opposite legs 112 of which terminate in hooks 113 and between which a roller 114 is rotatably supported. Each leg 1.12 carries a spring biased slide 115 which serves to hold the anchor roller assemblies 111 in position in the manner described further below. To locate the anchor roller assemblies 111 in position, a plurality of spaced transversely extending cross bars or pins 116 are provided within the beam 85 extending between opposite flanges 89. In use as shown in Fig. 22 and where a load 117 in this case an I-beam is to be secured in position on the tray of a vehicle which carries one or more load restraint apparatuses 84, the load 117 is positioned transverse to the apparatus 84 and beneath the webbing strap 87 which can be simply withdrawn by pulling from the respective winch assemblies 86. Anchor roller assemblies 1 1 1 are then positioned on opposite sides of the load 117 and hooked under the cross bars 116 adjacent to the load 117 such that the webbing strap 87 is constrained to pass along the beams 85 to the respective anchor roller assemblies 1 11 and then over the load 1 17. To locate the anchor roller assemblies 111, it is necessary to push the slides 115 upwardly either by the hand or by engagement with portion of the beam 85 such that when the hooks 113 are located under and engage the cross bars 116, the anchor roller assemblies 1 11 cannot be released unless they are pushed downwardly to move the slides 115 relatively upwardly to allow the hooks 113 to be detached. The webbing strap 87 can then be tensioned by operation of one or both winch assemblies 86. As referred to above, the webbing strap 87 can be initially tensioned by a tool engaged with the hexagonal head 108 to directly rotate the pinion 102 and thus drive sprocket 92 after which a tool may be engaged with the head 107 so that the worm 103 engages the pinion 102 for final tightening of the webbing strap 87 using the mechanical advantage provide by the worm/pinion gearing. The load 117 is then held firmly in position by the webbing strap tension created by interaction of the opposing winch assemblies 86. The winch assemblies 86 as described above may be used in a many different applications as self contained units as illustrated in Figs. 23 and 24. For this purpose, the internal mechanism of the winch assembly 86 is incorporated in a housing 118 which carries on one side the housing 103 containing the pinion/worm transmission to enable the winch assembly 86 to be actuated. The winch assemblies 86 in this case do not incorporate an idler or guide roller 1 10 with the webbing strap 87 extending from one end for coupling to any load. Referring now to Fig. 25, there is illustrated portion of a webbing strap tensioning apparatus 119 for tensioring a webbing strap typically around a load to restrain a load against movement. The tensioning apparatus 119 is actuated by means of a fluid actuator 120 having a piston rod 121. The piston rod 121 is coupled to the base member 122 of a substantially U-shaped bracket 123 which has a pair of opposite side arms 124. An axle

125 extends between the opposite side aims 124 and a clamp jaw holder 126 is mounted to the axle 125 for rotational movement about the axis of the axle 125. The clamp jaw holder

126 includes a pair of side arms 127 and a hollow cross member 128 which joins the arms

127 and which receives the axle 125. A clamp jaw 129 is located between the arms 127 and is spaced from and offset from the cross member 128. The clamp jaw 129 is mounted for slidable movement along the arms 127 towards and away from the cross member 1 8. The jaw 129 is provided with opposite tongues 130 (see Fig. 26) which extend outwardly of the ends of the arms 127. A spring or other biasing means (not shown) are provided to urge the jaw 129 towards the outer ends of the arms 127. Located within the U-shaped bracket 123 is a further U-shaped member 131, the opposite arms 132 of which are juxtaposed with the arms 124 of the member 123. The arms 132 are also provided with elongated slots 133 between which the axle 125 passes. Fixed to or provided on the arms 132 of the members 131 are racks 134 and pinion gears 135 fixed for rotational movement with the clamp jaw holder 126 about the pivot axis of the bolder 126 are in mesh with the rack 134. Upper and lower guides 136 extend above and below the arms 124 of the bracket 123 to guide movement of the U-shaped member 131 relative to the bracket 123. Located between opposite arms 1 2 of the member 131 is a clamp jaw carrier 137 carrying a second clamp jaw 13S which is of a channel-shaped cross section and complementary to the clamp jaw 129. Upper and lower guides 139 are also fixed to the clamp jaw carrier 137 and extend over the arms 124 of the bracket 123 to guide movement of the clamp jaw 138 relative to the U-shaped bracket 123 and U-shaped member 131. The guides 136 and 139 in the position of Fig. 25 abut each other. A first set of springs 140 between the bases of the U-shaped bracket 123 and member 131 normally biases the member 131 longitudinally away from the bracket 123. A second set of springs 141 are provided between the base of the U-shaped member 131 and clamp jaw carrier 137 to normally bias the jaw 138 away from the member 131. In use and as shown in Figs. 26 to 30, the tensioning apparatus 119 is supported on any suitable elongated base member 142 which is provided in an elongated slot 143 therein and stops 144 which are adapted to cooperate with the guides 139 to limit movement of the clamp jaw 138 and U-shaped member 131. When the fluid actuator 120 is actuated to advance the piston rod 121, the bracket 123 is moved outwardly to the right in Fig. 25. The jaw 138 however is prevented from moving through cooperation between the guides 139 and stops 144 and similarly the U-shaped member 131 is prevented from moving outwardly due to abutment between the guides 136 and 139. The relative movement between the bracket 123 and member 131 will cause the jaw member 129 to be rotated clockwise to the position of Fig. 26 due to the meshing pinions 135 and racks 134. In the position of Fig. 26, a webbing strap 145 is passed between the jaw member 129 and hollow member 128 and through the slot 1.43 in the elongated base member 142 ready to be tensioned or tightened. When the fluid actuator 120 is actuated to retract the piston rod 121, the bracket 123 is moved to the left as shown in Fig. 27. The relative movement between the bracket 123 and member 131 as accommodated by movement of the axle 125 in the slots 133 will cause

• through the intermeshmg pinions 135 and racks 134 pivotal movement of the jaw holder 126 which wraps the webbing strap 1 5 around the jaw member 129. This movement continues until the jaw member 129 is aligned with the jaw member 138 as shown in Figs. 28 and 29. At this position, the axle 125 moves to its limit position at the end of the slots 133. At the same time, the biasing springs 140 maintain the member 13.1 and jaw member 138 in a fixed position. Further retraction of the piston rod 121 will cause due to the engagement of the axle 125 with the ends of the slots 133, retracting movement of the member 131 with the bracket 123. The springs 141 between the guide member 136 and jaw carrier 137 however will maintain the jaw member 138 in a fixed position with the guides 139 thereof in abutment with the stops 144. Further retraction of the piston rod 1 1 moves the jaw 1 9 relatively towards the jaw member 138 until the tongues 130 contact the jaw members 138 thereby causing sliding movement of the jaw member 129 relative to the holder 126. At the limit of movement of the jaw members 129, the webbing strap 145 is sandwiched and clamped between the jaw members 129 and 138, Thereafter, further retraction of the piston rod 121 moves the whole assembly along the base member 142 thereby pulling the webbing strap 145 clamped between the jaw members 129 and 138 rearwardly thereby tensioning or tightening the webbmg strap 145. Where it is required to release tension in the strap, the actuator 120 is reversed in its operation to extend the piston rod 121 such that the apparatus 119 functions in reverse of the motion described in Figs. 26 to 30 whereby the strap 145 is released from between the clamping jaws 129 and 138. It will be appreciated that the tensioning apparatus 119 may be used in many different applications for tensioning or tightening a strap around a load. Thus the apparatus 119 may be used in combination with a beam and in place of the winch assemblies 86 of the embodiment of Fig. 17. The apparatus 119 however may be used in many other applications. Referring now to Figs. 31 to 34, there is illustrated a load restraining apparatus according to a further embodiment of the invention comprising a load carrying rack assembly 150 comprising an elongated load carrying beam 151 having a constant cross section along its length and preferably being formed as an extrusion. Mounted at Opposite ends of the beam 151 are respective winch assemblies 152 each having a bousing 153 comprising a pair of opposite housing parts 154 which are secured to an end of the beam 151 by suitable threaded fasteners 155 and which are further secured in an opposing mating relationship by further threaded fasteners or bolts 156. Captured between the housing parts 154 and supported by bearings or bushes 157 therein is a winch drum assembly 158 having an axial extending socket end 159 extending through one of the housing parts 154. A ratchet wheel 1 0 coaxial with the axis of rotation of the winch drum assembly

158 is provided at one end of the winch drum assembly 158 and is keyed thereto by means of an hexagonal opening 161 in the ratchet wheel 1 0 locating over a hexagonal land 162 on an end of the drum assembly 158 such that the ratchet wheel 160 is rotatable with the drum assembly 158. A ratchet wheel pawl 1 3 shaped from high tensile square bar or the equivalent, is fixed to a pivot shaft 164 and extends substantially at right angels thereto. The shaft 164 is supported by bearings 165 to opposite housing parts 154 for limited rotational movement about an axis parallel to the axis of rotation of the dπim assembly 158. The pivot shaft 164 terminates in a lever arm 166, rotation of which in a first direction will disengage the pawl 1 3 from the ratchet wheel 160 to allow the winch drum assembly 158 to "free wheel". Rotation of the lever arm 166 in the opposite direction will move the pawl 163 into engagement with the ratchet wheel 160 to prevent rotation of the winch drum assembly 158 in one direction to check back-run of the winch drum assembly 158. Each housing 153 also carries an idler roller 167 supported on a shaft 168 extending between the secured to each housing part 154 and defining a rotational axis of the roller 167 which is substantially parallel to the axis of rotation of the winch drum assembly 158. A webbing sling 169 is wound on one of the winch drum assemblies 158 and passes around the idler roller 167 and out through a slot 170 in the housing 153 carrying that winch drum assembly 158 and along the beam 151 to pass in through the corresponding slot 170 in the opposite housing 153 and around an idler roller 167 to be wound upon the other winch drum assembly 158. The beam 151 as referred to above is preferably formed as an extrusion and includes a pair of opposite upwardly extending side flanges 171 which define therebetween a channel 172 in which the webbing sling 169 is normally located. The side flanges 171 are shaped to receive wear strips 173 through a tongue and groove type connection. The wear Strips 173 are suitably formed of plastics, rubber or other wear resistant material. The side flanges 171 on their inner sides are provided with grooves 174 which extend the full length of the flanges 171. Further grooves 175 adjacent the grooves 174 are formed in the beam 151 in the bottom of the channel 172 and also extend the full length of the beam 151. A series of anchor roller assemblies 176 are capable of being secured at spaced locations along the beam 151 for efficient securing of a load to the beam 151 , Each anchor roller assembly 176 comprises a flanged anchor roller 177 which is supported for rotation on a on an axle 178 which at each end of the roller 177 joins arms 179 which extend at right angles to the axle 178 and which are turned back at their free ends to define hooks 180. The hooks 180 are spaced apart the same distance as the grooves 175 so as to be partially locatable therein as referred to further below. To locate and hold respective anchor roller assemblies 376 to the beam 151, a square- wave shaped anchoring arm 181 formed of spring steel or other resilient material is provided, the anchoring arm 181 having a series of transverse anchoring members 182 joining longitudinally extending members 183. Opposite members 183 are spaced apart to locate within the opposite grooves 174. When a longitudinal force is applied to the anchoring arm 181 to "stretch" the anchoring arm 181, the transverse dimensions of the ann 181 arc reduced with the arm members 183 moving towards each other. When the force is released, the resilience of the material of the arm 181 urges the arm members 183 outwardly away from each other to wedge the arm members 183 within the grooves 174 and thus lock the arm 154 at a set position in the beam 151. To position the anchor roller assemblies 176, the books 180 of an anchor roller assembly 176 are engaged with a selected transverse anchoring member 182 of the anchoring arm 181 and locate within the grooves 175. Anchor roller assemblies 176 can thus be located at a series of positions along the beam 151 in this manner as required. In use and as shown in Fig. 35, loads 184 and 185 are shown spanning and supported on the beams 151 of spaced rack assemblies 151 and the anchor roller assemblies 176 are positioned on opposite sides of and adjacent to the loads I 84 and 185 in the manner described above. The webbing sling 169 is then pulled from the winch assemblies 152 which are placed in the "free-wheel" mode by releasing the pawl arms 166 and looped between the anchor assemblies 176 on opposite sides of the loads 184 and 185 over the loads 184 and 185.29. The pawl arms 166 may then be pivoted to reengage the pawls 163 with the ratchet wheel 160. The opposite winch drum assemblies 158 may then be rotated by means of tools which engage with the sockets 159 of the winch drum assemblies 158. The webbing sling 169 can thus be wound in onto the winch drum assemblies 158 at each end of the beam 151 to thereby tighten and tension the webbing sling 1 9 over the loads 184 and 185, Each winch drum assembly 158 may be actuated in turn or only one winch drum assembly 158 may be actuated. Tension is maintained in the sling 169 by the pawl/ratchet engagement provided by the pawl 163 and ratchet wheel 160. The loads 184 and 185 are thus held firmly in position by the webbing sling tension created by interaction of the opposing winch assemblies 158. To release tension in the sling 169, one or both pawls 1 63 are released from the ratchet wheel or wheels 160 such that the winch drum assemblies 158 can free wheel. It may be necessary to take the tension in the sling 1 9 by a tool engaged with the socket end 159 of the winch drum assembly 158 to slightly rotate the drum assembly to allow release of the pawl 163. The load carrying rack assembly 10 may be mounted to many different types of vehicle. Typical applications are illustrated in Figs. 36 to 45. In Figs. 36 and 37, a pair of rack assemblies 150 are mounted to a utility or pickup vehicle 186 via a pair of U-shaped frames 187, the upstanding legs 188 of which engage with respective winch housings 153 through a spigot mounting arrangement comprising a spigot bracket 189 secured to the winch housing 153 by bolting, the spigot bracket 189 carrying a spigot 190 which extends into the leg 188 of the frames 187. The U-shaped frames 187 further include cross arms 191 between the legs 188 and formed integrally therewith and braced thereto by cross braces 192. The cross arms 188 and legs 191 are of tubular form, and the arms 191 seat within elongated mounts 193 which are arranged along the upper edges 194 of the side walls 195 of the vehicle 186. The mounts 193 are concave as at 196 on their upper sides so as to be complementary to the cross sectional shape of the arms 191. Interposed between the concave surface 196 of the mounts 193 and the arms 191 is a bearing or anti-slip material 197 of plastics or the like or alternatively the mounts 193 may be formed of a bearing or anti-slip material of plastics or the like. Securing lugs 198 extend downwardly from the arms 38 to secure the respective frames 187 to the inner sides of the side walls 195 by any suitable fasteners. For mounting .the rack assemblies 150 to the tray of a vehicle such as a utilities or pickup vehicles, but particularly for drop sided utilities or pickups, elongated strip-like mounting members 200 shown in Fig. 41 are provided, the mounting members 200 having a series of mounting apertures 201 by which the elongated mounting members 200 may be secured by suitable fasteners such as screws, or bolts at spaced apart positions substantially parallel to each other on opposite sides of the vehicle tray. The members 2-00 in addition are provided with a series of longitudinally extending slots 202 between respective mounting apertures. Removable mounting shuts 203 for supporting the rack assemblies 150 may be positioned along the mounting members 200 and engaged therewith. The struts 203 include substantially upright arm members 204 extending upwardly from and secured to base plates 205 and bracing arms 206 which extend between the upright arm members 204 and base plate 205. The base plate 205 as shown in Figs. 44 to 46 is provided on its lower side with a first fixed hook 207 and a movable and lockable hook 208 which has a leg 209 which extends through the base plate 205 into the arm member 204. A locking knob 210 is supported on a threaded stud 211 which extends through a slot 212 on an inner wall of the arm member 204. A wedge shaped member 213 is fixed to the stud 211 and extends along the arm member 204 for cooperation with the leg 209 of the hook 208. In use and as shown in Fig. 44-, the wedge shaped member 213 is retracted and the base plate 205 is moved downwardly i n the direction of the arrow A towards the mounting strip 200 (which in Figs. 43 to 46) is o^~ a length substantially the same as the base plate 205 and such that the hooks 207 and 208 moved into respective slots 202. The base plate 205 is then slid in the direction B along the mounting strip 200 so that the hooks 207 and 208 located on the underside of the base pi ate 200. The knob 21 is then released so that it can move downwardly along the slot 1. 1 and move the wedge shaped member 213 also downwardly to the position of Fig, 46. - The knob 21 can then be tightened on the stud 211 to clamp the member 213 in this position in which it cooperates with the leg 209 to urge the hook 208 into clamping engagement with the base plate 200 such that the Strut 203 is thus held positively in position to the mounting strip 200 as shown also in Fig. 43. For mounting of a load carrying rack 150 to the strut 203, a spigotted mounting bracket 214 similar to the arrangementl of Fig. 39 is provided for mounting of the winch housings 153 to the upper ends of the- strut 203. . The spigot of the bracket 214 may be inserted into the upper end of the stmt 203 or the upper end of the strut 203 may exitend into the spigot of die bracket 214. Of course other arrangements may be provided for mounting of the racks 150. Where the strut 200 is secured to the tray of a vehicle such as bolts, integral studs or Other fasteners 215, the tray is provided with a series of _.cut out regions of slot-like form which are aligned with the slots 202 to p rmit insertion of the hooks 207 and 208. Whilst the above has been given by way of illustrative embodiment of the invention, all such variations and modifications thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as defined in the appended claims.

Claims

2:4 CLAIMS

1. Load restraining apparatus including a housing, a flexible load restraining element extending into said housing, tensioning me-ans within said housing and adapted to be coupled to said load restraining element for application of tension to said load restraining element to restrain a load, said tensioning means including means for engaging intermediate portion of said element, and means for selectively actuating said tensiorώig means to draw said load restraining clement into said housing.

2. Apparatus as claimed in claim 1 wherrcin said load restraining element comprises a. chain and wherein said the means for tensioning the element comprises an actuator adapted to cooperate with a selected link of the chain.

3. Apparatus as claimed in claim 2 whe=rein said actuator has a head for cooperation, with said selected link or link, said head including an opening through which said chain passes.

4. Apparatus as claimed in claim 3 wherein said opening is formed such that in a first position of the chain in the opening, the chain can move freely through the opening and in a second position, the chain is captured against movement through the opening whereby actuation of the actuator in the second position of the chain causes said chain to be drawn into the housing.

5. Apparatus as claimed in claim 4 wherein said opening comprises a keyhole-shaped operiing having a slot-like portion in which a chain link can be captured against movement.

6. Apparatus as claimed in claim 4 or cl aim 5 and including a chain stripper or stop-, said head in one attitude cooperating with sai-d chain stripper or stop to urge the chain into the first position.

7. Apparatus as claimed in claim 6 and including guide means for guiding said head to said one attitude.

8. Apparatus as claimed in claim 7 wherein said guide means defines a tapering throat to guide the head to the one attitude.

9. Apparatus as cl imed in any one of claims 2 to 8 wherein said housing is defined by an elongated beam or member.

10. Apparatus as claimed m 9 and including a pair of spaced actuated means associated disposed and opposite ends of said beam and wherein said chain extends between opposite actuating means whereby the chain may be tensioned or tightened from each end.

11. Apparatus as claimed in any one of Hie preceding claims wherein said actuator comprises a linear actuator.

12. Apparatus as claimed in any one of claims 2 to 10 wherein said actuator comprises a rotatable drive wheel adapted to cooperate with the chain.

13. Apparatus as claimed in claim 12 wherein said drive wheel is coupled to a worm drive.

14. Apparatus as claimed in claim 13 wherein said worm drive includes a drive shaft coupled to said drive wheel whereby said drive wheel may be driven directly through said shaft.

15. Apparatus as claimed in claim 14 and including a wonn/pinion transmission for indirectly driving said drive wheel.

16. Apparatus as claimed in claim 15 wherein said worm pinion transmission includes a further shaft carrying a worm and wherein said drive shaft carries a pinion.

17. Apparatus as claimed in claim 16 wherein said worm of the further shaft may be selectively coupled with the pinion.

18. Apparatus as claimed in claim 17 wherein said further sruaft is supported for axial movement between a first disengaged position where the worm, is disengaged from the pinion and a second position where the worm is engaged with the pinion.

19. Apparatus as claimed in any one of claims 12 to 18 wherein said drive wheel cooperates with a further wheel forming a nip through which the chain may pass.

20. Apparatus as claimed in any one of claim 12 to. 18 and including additional tensioning means for pre-tensioning said the chain.

21. Apparatus as claimed in claim 20 wherein said tensioning means may comprise a tension spring in the housing secured to an end of the chain.

22. Apparatus as claimed in claim 20 wherein said tensioning means comprises a tension spring secured to a roller around which the chain passes.