Abstract:
A hoist assembly for overhead lifting including an upwardly extending attachment member, a downwardly depending shank coupled to the attachment member and having a polygonal cross sectional shape, a hoist body coupled to the downwardly depending shank, and a plate positioned between the upwardly extending attachment member and the hoist body, that defines a first circular aperture that matingly receives the polygonal shank and a second polygonal aperture laterally spaced from the first circular aperture. The plate is moveable between a first position, in which the polygonal shank extends into the first circular aperture, and a second position, in which the polygonal shank extends into the second polygonal aperture. Rotation of the attachment member with respect to the plate is permitted when the plate is in the first position, and rotation of the attachment member with respect to the plate is inhibited when the plate is in the second position.

Description:
BACKGROUND 
     The present invention relates to hoists and the connection between a hoist and a machine, track, arm or other structure. 
     SUMMARY 
     In one embodiment, the invention provides a hoist assembly for overhead lifting. The hoist assembly including an upwardly extending attachment member, a downwardly depending shank coupled to the attachment member and having a polygonal cross sectional shape and a hoist body coupled to the downwardly depending shank. The hoist assembly further includes a plate, positioned between the upwardly extending attachment member and the hoist body, that defines a first circular aperture that matingly receives the polygonal shank and a second polygonal aperture laterally spaced from the first circular aperture. The plate is moveable between a first position, in which the polygonal shank extends into the first circular aperture, and a second position, in which the polygonal shank extends into the second polygonal aperture. Rotation of the attachment member with respect to the plate is permitted when the plate is in the first position, and rotation of the attachment member with respect to the plate is inhibited when the plate is in the second position. 
     In another embodiment the invention provides a method of coupling an attachment member to a hoist body. The method includes positioning a plate between the attachment member and the hoist body in a first plate position; the plate has a first aperture and a second aperture. The method further includes inserting a shank of the attachment member through the first aperture into a mating recess in the hoist body to couple the attachment member to the hoist body, rotating the hoist body with respect to the attachment member and extracting the shank from the hoist body. The method further includes moving the plate from the first plate position to a second plate position, inserting the shank through the second aperture into the mating recess in the hoist body to couple the attachment member to the hoist body, and inhibiting rotation of the hoist body with respect to the attachment member. 
     In another embodiment, the invention provides an attachment assembly for coupling a hoist body to a support structure to selectively permit and inhibit rotation of the hoist body with respect to the support structure. The attachment assembly includes an attachment member having a first end and a second end, the first end is connectable to the support structure, and the second end defines a shank having a polygonal cross sectional shape. The attachment assembly further includes a receiving member that defines a through hole sized to receive the shank and permit rotation of the shank with respect to the receiving member, and a key member defining a first circular aperture and a second polygonal aperture spaced from the first aperture. In a first position, the shank extends into the first circular aperture to permit rotation of the attachment member with respect to the receiving member, and in a second position, the shank extends into the second polygonal aperture to inhibit rotation of the attachment member with respect to the receiving member. 
     Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a hoist assembly according to one embodiment of the present invention. 
         FIG. 2  is a close up perspective view of a first portion of the hoist assembly with a portion of a hoist body removed to show an attachment assembly. 
         FIG. 3  is a close up perspective view of a second portion of the hoist assembly with a portion of the hoist body removed to show the attachment assembly. 
         FIG. 4  is a cross-sectional view taken along line  4 - 4  of  FIG. 1  with a plate in a first position. 
         FIG. 5  is an exploded view of a portion of the hoist assembly of  FIG. 1 . 
         FIG. 6  is an exploded view of a hook sub-assembly of  FIG. 1  including a plate in the first position. 
         FIG. 7  is an exploded view of a hook sub-assembly of  FIG. 1  including the plate in a second position. 
         FIG. 8  is a bottom perspective view of the hook sub-assembly of  FIG. 7 . 
         FIG. 9  is a perspective view of the hook sub assembly of  FIGS. 7 and 8  with a portion removed for clarity. 
     
    
    
     DETAILED DESCRIPTION 
     Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. 
       FIG. 1  illustrates a hoist assembly  10  that includes a hoist body  12 , a first attachment member, such as the illustrated top hook  14 , coupled to the hoist body  12 , a second attachment member, such as the illustrated bottom hook  16 , coupled to the hoist body  12  via a chain  18 , and a plurality of cables  20  coupled to the hoist body  12 . The cables are operable to move the chain  18  with respect to the hoist body  12  in response to user actuation. Movement of the chain  18  with respect to the hoist body  12  thereby alters the distance between the bottom hook  16  and the hoist body  12 . A chain bag  22  is utilized to store excess length of chain  18  as the bottom hook  16  is moved toward the hoist body  12 . The illustrated top hook  14  engages a support structure  23  to couple the hoist body  12  to the support structure  23 . 
       FIG. 2  is a close up view of  FIG. 1  with a portion of the hoist body  12  removed to show an attachment assembly  24 . The attachment assembly  24  includes the hop hook  14 , a first block  26 , a second block  28 , a plate  30 , a pair of fasteners  32 , and a fastener  52  (see  FIG. 5 ). The pair of fasteners  32  extend through the hoist body  12 , the first block  26  and the second block  28  to secure the top hook  14  to the hoist body  12 . The hoist body  12  defines a blind hole  34 , such as a recess, that receives at least a portion of the first and second blocks  26 ,  28  and the plate  30 . The first and second blocks  26 ,  28  are not rotatable about a vertical axis  33  within the hole  34 , and are consequently fixed for rotation about the vertical axis  33  with the hoist body  12 . Although first and second blocks  26 ,  28  are illustrated, other quantities, shapes and constructions of parts can be utilized. Although the illustrated fasteners  32  include shoulder bolts with respective washers and nuts, other fasteners can be utilized to couple the attachment assembly  24  to the hoist body  12 . 
       FIG. 3  further illustrates the hoist assembly  10  with the second block  28  and a different portion of the hoist body  12  removed to further illustrate the blind hole  34  and the plate  30 . The plate  30 , or key member, defines a first aperture  40  having a substantially circular cross-section and a second aperture  42  having a polygonal cross-section. The top hook  14  includes a shank  44  connected to the hook at one end and includes an opposite polygonal end  45 . The shank  44  is at least partially received in the first and second blocks  26 ,  28  and in the first aperture  40  in the plate  30 . 
       FIG. 4  shows the shank  44  extending through the second block  28  and into the first aperture  40  of the plate  30 . The first and second blocks  26 ,  28  each define a depression  46   a ,  46   b , respectively (see  FIG. 5 ), that together form an opening  46  sized to receive the shank  44 . The shank  44  includes an annular recess  48  that is sized to receive an annular rib  50  in the opening  46  formed between the first and second blocks  26 ,  28 . The engagement of the annular rib  50  in the annular recess  48  retains the shank  44  of the top hook  14  in the first and second blocks  26 ,  28 . The shank  44  is permitted to rotate within the opening  46  relative to the blocks  26 ,  28 . 
       FIGS. 2-6  show the attachment assembly  24  with the plate  30  in a first orientation with respect to the shank  44 . In the first orientation, the shank  44  extends through the opening  46  and the polygonal end  45  is at least partially received in the first aperture  40 . Consequently, the hoist body  12 , first block  26 , second block  28  and plate  30  freely rotate about the vertical axis  33  with respect to the top hook  14  when the attachment assembly  24  is in the first orientation. The first aperture  40  is sized to receive the polygonal end  45  of the shank  44  and permit rotation of the polygonal end  45  within the first aperture  40 . 
     As shown in  FIGS. 4-6 , the fastener  52  is inserted through an aperture in the second block  28  and threaded into an aperture in the first block  26  to couple the first block  26  to the second block  28 , and thereby retain the shank  44  within the opening  46  formed between the first and second blocks  26 ,  28 . Other fasteners, or methods of fastening can be utilized to removably couple the first and second blocks  26 ,  28  together. 
       FIG. 6  shows that the plate  30  defines a first bevel  54  around the first aperture  40  and a second bevel  56  around the second aperture  42 . The first and second bevels  54  and  56 , guide the polygonal end  45  of the shank  44  into the respective aperture  40 ,  42 . The illustrated bevels  54  and  56  are shown by way of example only and are not intended to limit the scope of the present invention. Other configurations and arrangements of the plate and the apertures are possible and can be utilized in addition to or in lieu of the illustrated structure. 
       FIGS. 7-9  show the attachment assembly  24  with the plate  30  in a second orientation with respect to the shank  44 . In the second orientation, the polygonal end  45  of the shank  44  is at least partially inserted into the second aperture  42 . The second aperture  42  is sized to receive the polygonal end  45  of the shank  44  and limit or inhibit rotation of the shank  44  with respect to the plate  30 , which thereby limits or inhibits rotation of the hoist body  12  with respect to the top hook  14 . The second aperture  42  is slightly larger than the polygonal end  45  to form a slip fit in the second aperture  42 . Consequently, slight rotational movement of the polygonal end  45  within the second aperture  42  is permitted, but substantial rotation of the polygonal end  45  within the second aperture  42  is inhibited. 
     In the illustrated embodiment, the polygonal end  45  and the second aperture  42  are square in shape. Thus, the hoist body  12  can be positioned at four distinct orientations, spaced-apart in ninety degree increments, namely 0°, 90°, 180° or 270°, with respect to the top hook  14 . In other embodiments, other polygonal shapes, such as a triangle, a pentagon, a hexagon, an octagon, and the like, can be utilized. In still other embodiments, non-polygonal shapes, such as a five point star, a six point star, and the like, can be utilized. 
     The quantity and angle of the orientations for a specific embodiment depend primarily upon the geometry of the polygonal end  45  and the second aperture  42 . In some embodiments, the polygonal end  45  and the second aperture  42  have the same shape, whereas in other embodiments, the polygonal end  45  and the second aperture  42  can have different shapes that are compatible with one another (a triangle shank in a six-sided star aperture, for example). 
     In order to rotate the plate  30  from the first orientation to the second orientation and vice versa, a user removes the fasteners  32  from the hoist body  12  and the first and second blocks  26 ,  28 . The hoist body  12  is removed from the first and second blocks  26  and  28  and top hook  14 . The plate  30  is removed from the blind hole  34  in the hoist body  12  and rotated about the vertical axis  33 . The plate  30  is re-inserted into the blind hole  34  and the first and second blocks  26 ,  28  are inserted into the blind hole  34 . The polygonal end  45  of the shank  44  is inserted into the other of the apertures in the plate  30 . The fasteners  32  are re-inserted into the hoist body  12  and first and second blocks  26 ,  28  and are tightened to couple the top hook  14  to the hoist body  12 . This process is repeated whenever it is desired to alter the relationship between the hoist body  12  and the top hook  14 , for example, to permit or resist rotation of the hoist body  12  with respect to the top hook  14 . If free rotation of the hoist body  12  with respect to the top hook  14  is desired, the plate  30  can optionally be omitted. 
     The illustrated top hook  14  includes a substantially c-shaped hook that defines an opening and includes a clasp that is moveable to substantially cover the opening. In other embodiments, the attachment member is a trolley mount or other similar mounting device. 
     The illustrated arrangement selectively permits or inhibits rotation of the hoist body  12  with respect to the top hook  14  without adding or removing different parts. The same plate  30  is used to both inhibit and permit rotation of the hoist body  12  with respect to the top hook  14 . This is advantageous because the same structure is utilized for both functions, i.e. no extra parts, fasteners, pins, screws, clamps or the like are needed. Furthermore, it permits the same top hook  14  to be utilized with a hoist body  12  in which the user can determine the rotational relationship between the hoist body  12  and the top hook  14  without requiring additional components or separate top hook assemblies. 
     Various features and advantages of the invention are set forth in the following claims.