Abstract:
Cable supported hook apparatus provides a U-shaped upward facing opening for transporting a truss. A cam pivotably mounted opposite the opening has a serrated edge opposite a handle. A slot in the opening permits a spring to urge the cam from a released orientation to an engaged orientation with the serrated edge extending through the slot. In the released orientation, a knob retractable spring driven pin extension can extend through a hole in the cam and secure it in place. In use, the handle is first used to rotate the cam to the released and secured orientation. After engagement with the truss, the extension is retracted by the knob which permits the cam to engage the truss. After transportation a release cable rotates the cam to the released and secured orientation to free the truss.

Description:
FIELD OF THE INVENTION  
       [0001]     This invention relates to hook apparatus used at a construction site for gripping a truss member during transportation to its final location on a building, and then remotely releasing the truss.  
       BACKGROUND OF THE INVENTION  
       [0002]     A variety of hooks are available to engage and transport various items. The majority of hooks utilize a downwardly or horizontally directed opening which mount a pivotable cam to engage the transported item and secure it in place. While most hooks are arranged to engage and disengage the hook from the transported item, none are arranged to disengage the hook remotely. Since this hook is intended to be used to transport a truss to its final location on a building, the truss will always be transported to an elevated location. Removing a hook from a truss in an elevated location poses the safety hazzard of falling to the worker. It would be advantageous if the hook could be released from a lower remote location to eliminate this hazard.  
       SUMMARY OF THE INVENTION  
       [0003]     The problem addressed relates to hooks used to engage, secure and transport roof trusses during construction, and to release the hook when the truss is in its final elevated location. Currently hooks used in construction to elevate a truss to its final location in a structure must be disengaged by hand. Since a truss by its very nature is always installed at the highest point on a building, this manual removal presents a considerable risk of falling.  
         [0004]     This hook has an upwardly directed U-shaped opening for holding and supporting the truss. A spring driven cam, extending through a slot into the opening, grips the truss during transport. A release cable, operable from a safe location at a lower level, is manually operated to pull against the cam spring and rotate the cam outward from the opening to release the truss from the cam. In this released position a spring driven extension from a pin in the apparatus can pass through a hole in the cam to secure it in the rotated orientation where the truss is free. The cam has a handle which permits rotating the cam to the released position manually to permit initially enclosing the truss. The pin has a knob to pull the spring driven extension outward from the cam hole to release the cam. This is used after the truss is initially enclosed to permit the cam spring to drive the cam against the truss and secure the truss for transport.  
         [0005]     While the figures illustrate the use of two hooks for transporting the truss, it is possible to use a single hook for transporting a small truss. In a considerable number of operations however, the truss is large enough to require the use of a pair of hooks for transport. Since this later operation is more complex this is the one described, however the operation for a single hook is similar.  
         [0006]     First the cam for one hook is rotated outwardly using the handle extension, until the spring driven extension from the pin is aligned with the hole through the cam, which then secures the cam in this orientation outside the U-shaped openings. The hook, attached to lifting cables with its U-shaped openings facing upward, is then positioned under one end of a truss such that the U-shaped opening envelopes an inclined upper board of the truss. The spring driven pin extension is then pulled outward manually, to permits the cam spring to force the cam against the truss to grip and secure the truss in place. This process is repeated on the opposite end of the truss for the other hook.  
         [0007]     The truss is then elevated into its final location on the building using the suspension cables. When the truss is in its final location, the release cables for both hooks are then pulled manually until the cams are rotated free of the truss and again engaged by their respective spring driven extensions from the pins. This secures the cams in an orientation outside of their respective U-shaped opening and frees the hooks from the truss. The freed hooks are then simply lowered from the truss to release them, and the process repeated for the next truss. When only a single hook is used, it is manipulated in the same manner as the pair of hooks described above, only the attachment point to the truss is changed, since when only a single hook is used the point of attachment of the hook must be at or near the center of balance of the truss.  
         [0008]     Since a release cable can be made any desirable length, it can even be extended down to the ground to provide maximum worker safety. In a second embodiment, the U-shaped opening of the hook can be made adjustable in width. This permits using the hook with the different width truss cross-sections normally used in construction. Without this alternative hooks would have to be provided which have various widths corresponding to the various truss widths.  
         [0009]     As indicated above, the truss hooks are used in pairs for a large truss with the hooks supporting the opposite ends of the truss. The hook pairs can be separated by a spreader bar which has the proper length for the truss being raised. The hooks grip the uppermost inclined boards of the truss. The lower connecting portion of the hook&#39;s U-shaped opening can have an upwardly directed V-shaped cross-section to accommodate this inclination, which will result in the inclined upper truss boards always bearing directly against one of the V-shape sides. A number of pointed rods can be mounted through each side of the V-shaped edge with their points extending outward perpendicular to the sides. These pointed rods would engage the wood of the boards to prevent the truss from translating with respect to the hook during transit. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1  shows a pair of truss hooks supporting a truss;  
         [0011]      FIG. 2  shows a side view of an assembled fixed opening truss hook;  
         [0012]      FIG. 3  shows an exploded view of the major parts of a fixed opening truss hook;  
         [0013]      FIG. 4  shows a side view of an assembled truss hook which has an adjustable width opening, adjusted to maximum width, with some parts being removed and with a cut-out provided to aid in description;  
         [0014]      FIG. 5  shows a cross-section view of a truss hook with a adjustable width opening supporting a truss;  
         [0015]      FIG. 6  is the same as side view of  FIG. 4  excepting that the opening is adjusted to minimum width;  
         [0016]      FIG. 7  is a side view of  FIG. 4  looking inward toward the movable part of the U-shaped opening and  
         [0017]      FIG. 8  is cross-section  8 - 8  of  FIG. 7 . 
     
    
       [0018]     The follow descriptions relating to the drawings, including left, right, up and down, refer to the relative positions of elements as shown on the above drawings in order to facilitate the detailed description of the invention.  
       DETAILED DESCRIPTION OF THE INVENTION  
       [0019]      FIGS. 1, 2  and  3  illustrate truss hook  10 . A pair of hooks  10  are shown supporting truss  12  by its opposed inclined upper boards  14 . Each hook  10  is supported by a suspension cable  16  having a spreader bar  18  which spaces the hooks the proper distance apart.  
         [0020]     An essentially planar and rectangular steel strap  26  is bent to form U-shaped opening  28  such as to provide a hook structure  24 . Lower reinforcement  30  and upper reinforcement  32 , shaped to conform to the outer shape of bent strap  26 , are both welded perpendicular along the strap center. A gap  42  is provided between lower reinforcement  30  and upper reinforcement  32 . A slot  34  is provided through strap  26  which is centered along the length of strap  26  opposite gap  42 . Slot  34  provides an opening sized to permit the serrated edge  37  of cam  36  to extend into U-shaped opening  28 . Top plate  38  and bottom plate  40 , located on opposite sides of lower reinforcement  30  and upper reinforcement  32  are spaced apart by these reinforcements and cover gap  42 . The spacing between plates  38  and  40  permit cam  36  to pivot between them.  
         [0021]     A nut  522  secures bolt  521  through aligned mating holes  52  in top plate  38 , in upper reinforcement  32  and in bottom plate  40 , attaches the upper end of the plates on opposite sides of the upper reinforcement. A nut  542  secures bolt  541  through aligned mating holes  54  in top plate  38 , lower reinforcement  30  and bottom plate  40 , attaches the lower end of the plates on opposite sides of lower reinforcement  30 . A bolt  561  is secured by a nut  562  extends through holes  56  in top plate  38  and bottom plate  40 . Bolt  561  provides support for cable  20  and provides a downward direction where the cable exits from the hook, its purpose being described further later.  
         [0022]     Cam  36  has opposed extensions, handle  19  which extends outward in one direction, and serrated edge  37  which extends outward in the opposite direction. Holes  58  in top plate  38 , in cam  58 , and in bottom plate  40  are provided. Nut  582  secures bolt  581  extending upward through holes  58  to rotatably secure cam  36  between top plate  38  and bottom plate  40 . Bolt  581  provides pivotal support for cam  36 . Cam  36  can rotate around bolt  581  such that handle  18  can be positioned between the locations as shown in solid and in dashed outline in  FIG. 2 , which will result respectively in serrated edge  37  extending within opening  28  to grip a truss located within the opening, or withdrawing from the opening to release the truss.  
         [0023]     Suspension cable  16  engages shackle  22 , which is attached to hook  10  through hole  50  by a bolt  501  extending downward through the shackle engaged by a nut, not shown. Suspension cable  16  suspends hook  10  such that U-shaped opening  28  opens upward.  
         [0024]     One end of release cable  20  is attached to cam  36  by means of a bolt  441  and a mating nut, not shown, through a mating hole  44  in cam  16 , not shown. Cable  20  extends over bolt  561  secured by a nut, not shown, which extends through aligned holes  56  through top plate  38  and bottom plate  20 . The operation of release cable  20  will be described further later.  
         [0025]     Pin  45 , which has a spring driven extension from one end and a retracting knob on the opposite end, is mounted and retained within hole  46  in bottom plate  40  using an interference fit. Pulling on the knob of pin  45  against the spring will retract the extension within the body of the pin. When extended the extension of pin  45  can extend into a locking hole  49  in cam  36 , but only when cam  36  is rotated counterclockwise to the orientation shown in the dashed outline in  FIG. 2 , where the serrated edge  37  of cam  36  is withdrawn from U-shaped opening  28 . Since the extension from pin  45  is spring driven, whenever locking hole  49  in cam  36  is rotated to a position opposite pin  47 , the extension will be forced by its spring into the locking hole.  
         [0026]     A pin  61 , not shown in these figures, is mounted in hole  60  in bottom plate  40  and extends outward to abut top plate  38 . A spring  63 , not shown in these figures, is secured by pin  61  on one end and is secured on the opposite end by spring hole  62  in cam  36 . With this arrangement, spring  63  will urge cam  36  clockwise. A clockwise rotation will urge serrated edge  37  of cam  36  through slot  34  into U-shaped opening  28 . With this arrangement, serrated edge  37  of cam  36  will always be urged through slot  34  into U-shaped opening  28  by spring  63  unless the cam is held in the counter-clockwise orientation by the spring driven extension from pin  45  extending through hole  49 . The location of spring  63 , which is identical in location and operation in hook  10  and in hook  11 , is described further as part of a following hook  11  description.  
         [0027]     Release cable  20  is attached through a hole  44 , not shown, by a bolt  441  extending through an eyelet attached to the end of the cable and hole  44  which is secured by a matching nut.  
         [0028]     Hook  10  has a fixed U-shaped opening  28 . Trusses come in several widths, depending upon the number of stacked boards making up an individual truss. As mentioned above, in construction where a variety of truss widths are used, individual truss hooks  10  providing the required different width openings can be provided. In some circumstances, it may be more useful if the width of the hook opening could be changed on site to match the different truss widths with only one type of hook required.  
         [0029]     Hook  11 , illustrated in the  FIGS. 4, 5 ,  6 ,  7  and  8 , has a U-shaped opening  29  which can readily be varied in width on site. The parts, their operation and their locations for hook  11 , which are not related to the width adjustment of U-shaped opening  29 , are the same for hook  11  as for hook  10  and operate in the same manner. Consequently, the following description of the construction and operation of hook  11 , excepting those parts related to the change of the width of U-shaped opening  29 , utilize the same parts with the same operation and locations. Consequently, the following discussion of hook  11  also provides a further description of the operation of hook  10 . In particular,  FIG. 6  shows hook  11  with spring  63  in place. Spring  63  in hook  11  has the same location, is attached in the same way, and provides the same function here as for hook  10 .  
         [0030]     Hook  11  has only one of the opposed sides and the lower connecting portion of U-shaped opening  29  provided by strap  27 . This is unlike hook  10  which has both of the opposed sides and the lower connection portion of U-shaped opening  28  provided by strap  26 . The opposite side of U-shaped opening  29  of hook  11  has a movable jaw which can be moved to provide a variable width opening. Strap  27  is also made wider than strap  26  to accommodate the variable width apparatus.  
         [0031]     Upper reinforcement  32 , identical to the part used in hook  10 , is welded centered and perpendicular to strap  27  with a shackle hole  50  and a connecting hole  52 . Here lower reinforcement  31 , is dissimilar to lower reinforcement  30  in that it only extends along the right side of strap  27 . Lower reinforcement  31  is also welded centered and perpendicular to the strap, with the same size gap provided between lower reinforcement  31  and the upper reinforcement  32  as in gap  42  for hook  10 . A centered vertical slot  35  through strap  27 , the same size as slot  34  through strap  26 , again provides access for the serrated edge  37  of cam  36 . Hole  52  is again provided for nuts and bolts, not shown, to attach top plate  38  and bottom plate  40  on opposite sides of upper reinforcement  32  such as to cover the gap between them. Top plate  38  and bottom plate  40  for hook  11  are identical to those for hook  10 .  
         [0032]     Lower reinforcement  31 , top plate  38  and bottom plate  40  all have a hole  55  arranged to attach the lower end of bottom plate  40  and top plate on opposite sides of the lower reinforcement using a bolt and nut, not shown.  
         [0033]     Pin  45 , which has a spring driven extension and a retracting knob, is again attached extending upwardly by an interference fit through hole  48  in bottom plate  40 . As described earlier, the working parts, other than those related to changing the width of U-shaped opening  29  are the same in hook  11  as in hook  10 . Therefore all of the holes provided for top plate  38 , bottom plate  40 , cam  36 , cable  20 , pin  45 , extension  48  and spring  63  are in the same location with the same bolts and nuts provided for hook  11  as for hook  10 . This illustration of the attachment of spring  63  to hook  11  is identical to its attachment in hook  10 , and thus also illustrates the attachment of the spring for hook  10 .  
         [0034]     An optional guard  74 , formed from a metal strap wider than the knob of pin  45 , is attached between upper reinforcement  50  and lower reinforcement  31  to protect the pin from damage. If desired, a similar guard arrangement could also be provided for hook  10 .  
         [0035]     The essential difference between hook  11  and hook  10  is the ability of hook  11  to adjust the width of U-shaped opening  29 . The adjustment apparatus consists of the apparatus located on the lower and left side of U-shaped opening  29 .  
         [0036]     The lower portion includes the leftward extension of strap  27 , and a hollow outer sleeve  66  which has a rectangular shaped cross-section. Outer sleeve  66  is welded across the bottom of the leftward extending portion of strap  27 . Outer sleeve  66  slideably encloses hollow inner sleeve  68  which has a mating rectangular shaped cross-section. Cap  70 , welded to the right end of outer sleeve  66  has a centered hole sized to admit threaded rod  72 . Washer  76  encloses the left end of rod  72 . The outer portion of washer  76 , which abuts inner sleeve  68  at four points at the four sides of inner sleeve  68 , is welded to the sleeve at those four points. Pins  77 , located on opposite sides of washer  76 , extend perpendicularly through mating holes in rod  72  with an interference fit, such that one of the pins will engage the washer whether rod  72  is translated to the right or to the left. Nut  73 , welded to the outside of cap  70  mates with rod  72 . A knob  78  is attached o the end of rod  72 . With this arrangement, when knob  78  is rotated rod  72  will translate within nut  73 . This translation of rod  72 , acting through pins  77 , will also translate washer  76  and attached inner sleeve  68 .  
         [0037]     Base  84  is welded across the top of the leftward extending portion of strap  27 . Base  85  is formed by a rectangular shaped planar strap. Inverted V-shaped enclosure  86 , formed by bending another rectangular shaped strap along its length, matches base  84  along its open side which is welded along the top of the base. A number of spaced apart pointed rods  88  are welded to and extend a small distance outward through mating holes on both sides of the length of inverted V-shaped enclosure  86 . Pointed rods  88 , being inclined by the inverted “V” shape of enclosure  86 , will better engage the inclined upper board of truss  12  located within U-shaped opening  29  to prevent the truss from translating with respect to the opening.  
         [0038]     Vertical jaw reinforcements  82  are welded along opposite sides along the outside of jaw  80 . Jaw  80 , has a hole  81  with a large upper rectangular opening which interconnects a smaller rectangular shaped lower opening. The smaller lower rectangular opening encircles and is welded to the outer end of inner sleeve  68 . The larger adjoining rectangular upper opening permits strap  27 , outer sleeve  66  attached across the bottom of the strap, and attached base  84  and enclosure  86  attached across the top of the strap, to extend through jaw  68 . With this arrangement when inner sleeve  68  is translated by rotating bolt  72 , attached jaw plate  78  and its jaw reinforcements  82  will also be translated and either close or open U-shaped opening  29 .  
         [0039]     Truss  12  is shown in  FIG. 5  engaging the rightmost side of V-shaped enclosure  86  and the pointed rods  88  on that side. Truss  12  is shown inclined because the portion of the truss which is engaged is the inclined uppermost board, as is shown in  FIG. 1 . With this arrangement the inclined uppermost board of truss  12  will always have the proper angle to engage either the right or the left side of enclosure  86  and its respective outward directed pointed rods  88 .  
         [0040]     When hook  11  is used, the width of the U-shaped opening  29  is first adjusted to correspond to the width of the particular truss  12  to be lifted, which depends upon the number of truss boards used.  FIG. 6  illustrates a truss of one board and  FIG. 4  illustrates a truss of three stacked boards. The adjustment is accomplished by rotating knob  78  attached to rod  72 , which will translate outer jaw  80  and its attached parts, until the desired width U-shaped opening  29 , corresponding to the width of the truss to be moved, is obtained. Note that when hook  10  is used, this step is replaced by selecting a hook with the required width.  
         [0041]     The following operations, with the exception of the above changes for the width of hook  11  or the selection of a proper hook  10 , are the same for either hook  10  or  11 , therefore only the operation of hook  10  is described below. Two hooks are necessary to lift a both ends of a truss, therefore a hook  10  is provided for the two ends of the truss.  
         [0042]     First, the serrated edges  37  of cams  36  are withdrawn from slots  34  and U-shaped openings  28  in hooks  10  by manually rotating the cams, using handles  18 , until the serrated edges are moved outward from U-shaped openings  28 , and until pins  45  are aligned with holes  49  to secure the cams at this location. Hooks  10  are then placed under opposite ends of the topmost board of the truss to be transported, as shown in  FIG. 1  for truss  12 , and pins  46  then pulled outward to permit springs  63  to release cams  36  which will then rotate clockwise and drive their serrated edges  37  against the truss. This secures a hook  10  around each end of truss  12 . Truss  12  is then hoisted into its final position on the building. Downward extending cables  20  from each hook  10 , resulting from the cables passing over bolts  56 , are then used to rotate the cams  36  counter-clockwise against springs  63  which will move the serrated edges  37  of hooks  10  outward until they are withdrawn from their respective U-shaped openings  28  into slots  34 , and until the extensions from pins  45  extend into holes  49  and secure the cams at this rotation where the truss  12  is freed. Hooks  10  are than simply lowered away from truss  12  and the above process repeated to place the next truss into position. Other similar arrangements could also be provided for adjusting the width of U-shaped opening  29 , which would readily occur to those skilled in the art.  
         [0043]     As discussed earlier, rather than providing apparatus to change the width of U-shaped opening  28 , hook  10  could be made with different widths openings corresponding to the multiples of widths provided by different truss widths. Accommodating different width trusses would then become merely a matter of selecting a hook  10  having the proper width opening.  
         [0044]     Using a cable to release the hook from a truss, which has been elevated to its final location on a building, greatly reduces the hazard inherent in the present construction operation. Presently a workman must climb up to the hook location, after the truss has been elevated to its location on a building, to release the hook. Since the truss is part of the roof structure, this is always the highest point on a building. Consequently, removing a hook at this location will always be hazardous. Since the cables used to release the hooks in this invention can be made any length, they can even reach down to the ground which will completely eliminate the hazard.  
         [0045]     The arrangement for changing the width of the U-shaped opening  29  for hook  11 , described above, namely using a rotating bolt  72  to change its width of U-shaped opening  29 , is only one of a number of similar arrangements that could be used. As an example, rather than using a threaded rod  72  and interacting parts, these could be dispensed with, and pairs of opposed holes in both the outer sleeve  66  and the inner sleeve  68  provided. The pairs of holes in the sleeves would be spaced apart the same distance as the difference in truss widths, and arranged such that the holes in the inner sleeve  68  and the outer sleeve  66  would be aligned in sequence when the inner sleeve is moved the width of a single truss board within the outer sleeve. The opposed holes in the sleeves would become aligned at each different truss width. A pin with an extending spring loop at an end opposite a knob could be pushed through the aligned holes in the two sleeves to secure them together. The spring loop would retain the pin in place.  
         [0046]     A modification in mounting the pointed tips used to prevent translation of the truss would be to rotate both the inner and outer sleeve forty five degrees such that one of the corners is innermost. This would eliminate the requirement for a base and enclosure to attach the pointed rods inclined outwardly and inwardly from each side, since the two upper surfaces of the outer sleeve would provide the required angle.  
         [0047]     While this invention has been described with reference to illustrative embodiments, these descriptions are not intended to be construed in a limiting sense. Various modifications of these illustrative embodiments, as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to these descriptions. It is therefore contemplated that the appended claims will cover any such modifications or embodiments as fall within the true scope of the invention.