Abstract:
A shovel dipper bail assembly including a bail having a central cylindrical portion and a lifting hitch rotatably connected to the cylindrical portion, the hitch assembly extending only slightly above the cylindrical portion and having lift cable connection means on opposite sides of the bail.

Description:
BACKGROUND AND SUMMARY OF INVENTION 
     This invention relates to a shovel dipper bail assembly and, more particularly, to an assembly which permits the dipper to be raised higher on a given machine before it interferes with the boom tip sheaves than prior assemblies. 
     Power shovels have been employed in excavating since before the turn of the century, viz., steam shovels. Over all of these years, it is apparent that many design improvements have been made but a long-standing problem has resided in the inability of raising the dippper to the maximum height possible. 
     Conventionally, a power shovel includes a lifiting boom mounted on the prime mover and, intermediate the length of the boom, the dipper stick is pivotally mounted thereon. The outer end of the boom is equipped with cable sheaves and cables are entrained therein for connection with the bail of the dipper. The cables are connected to the bail of the dipper by means of a hitch assembly which heretofore has limited the height to which the dipper can be elevated. For example, in co-owned, expired U.S. Pat. No. 2,034,854, a lifting hitch is seen that projects substantially above the bight of the U-shaped bail. Such an arrangement has been generally employed down to the present where padlock lugs have been welded to the bail bight in order to provide a pivotal mounting for the hitch. 
     Over the years, other expedients have been attempted to increase the ability to elevate the dipper. It will be appreciated that the higher the dipper can be raised--relative to the lifting boom--the higher the bank in which the machine can be operated and it is also possible to dump from higher heights to suit larger trucks--thereby extending the performance capability range of a given machine. One expedient has consisted of &#34;D-rings&#34; which permitted the cable connection to the bail to be substantially at the bight level, but this expedient was rejected by the excavating art because it resulted in accelerated wear on the lifting cables. 
     According to the instant invention, we have achieved the goal of substantially maximum elevatability without the attendant disadvantages of the previously employed D-ring construction by utilizing a lift hitch assembly which is rotatably mounted on a cylindrical section of the bail bight. Advantageously, the cable connections are in the form of the well-known D-rings so as to provide a profile of lifting hitch which is just slightly above the bail--thereby enabling the dipper to be raised to maximum possible elevation. Even though the art workers knew of the D-ring connnections for lifting cables, and also had central cylindrical sections on the bail bights, no one was able to bring these two concepts together to provide the advantage of maximum elevatability of the dipper. 
     Other objects and advantages of the invention may be seen in the details of the ensuing specification. 
    
    
     The invention is described in conjunction with the accompanying drawing, in which 
     FIG. 1 is a schematic elevational view, partially in section, of the forward (working) end of a power shovel; 
     FIG. 2 is an enlarged fragmentary view taken along the sight line 2--2 of FIG. 1 and which essentially shows the inventive bail assembly in front elevation; 
     FIG. 3 is a fragmentary sectional view taken along the sight line 3--3 applied to FIG. 2; and 
     FIG. 4 is an exploded perspective view of the lifting hitch of the invention shown in conjunction with a fragment of a bail illustrated in dashed line. 
    
    
     DETAILED DESCRIPTION 
     In the illustration given and with reference first to FIG. 1, the numeral 10 designates generally a power shovel equipped with a lifting boom 11 having cable sheaves 12 at the outer boom end, the inner end of the boom being mounted in the cab 13. 
     A dipper stick 14 equipped with a dipper 15 at the outer end thereof is pivotally mounted on the boom 11 and is equipped with a bail 16. Lifting cables generally designated 17 are connected between the bail and are entrained over the sheaves 12 for connection to a winch (not shown) within the prime mover of the power shovel 10. This environmental description for the invention is generally conventional and has been utilized in the construction of power shovels for many years. 
     BAIL 
     The bail 16 can be seen in enlarged form in FIG. 2 and includes a generally U-shaped member--the bail being shown only fragmentarily in order to conserve drawing space. The bail 16 includes a pair of legs 18 which are equipped with pivotal connections at the lower ends thereof as at 19 for pivotal engagement with the sides of the dipper 15. The bail further includes an integral, connecting bight 20 extending between the two depending legs 18. 
     The bight 20 has a central cylindrical portion 21 which can be best appreciated from a consideration of the central portion of FIG. 3. Advantageously, the bail can be cast or formed to provide such a central cylindrical section. Rotatably mounted on the bail central cylindrical section is a lifting hitch generally designated 22. 
     LIFTING HITCH 
     The parts of the lifting hitch can be appreciated best from a consideration of FIG. 4 where the same are shown in exploded form. In FIG. 4, the numeral 22a--see the lower right hand portion--designates a generally U-shaped bracket which partially encircles the central cylindrical portion 21 of the bight 20. The bracket 22a has a pair of upstanding arms as at 23 and is closed across the top thereof by means of a closure 24--see the upper portion of FIG. 4. 
     In the illustration given, the closure 24 is equipped with a depending portion 25 which is internally contoured to a segmental cylindrical configuration. In like fashion, the bracket 22a is similarly contoured as at 26. These provide complementary surfaces for the mounting of a split cylindrical bearing 27 which encircles the central cylindrical section 21 of the bight 20. In the illustration given four bolts 28 are employed to secure the closure 24 to the bracket 22a. 
     Each of the arms 23 of the bracket 22a are equipped on the outer sides thereof--relative to the bight 20--with a D-ring as at 30. The D-ring is essentially a half sheave and receives the looped bottom end of a cable such as that designated 17a in FIG. 4. The open bottom side of each D-ring is closed by an arcuate member 31 which is boltably secured to the closure 24 by means of bolts 32. 
     Provided on the upper surface of the closure 24 is a bumper means 33 which can be seen in FIG. 3 to be coming into close proximity to the boom sheaves 12-- the bumper means being advantageously arcuately curved as seen in FIG. 3 corresponding to the curvature of the sheave means 12. 
     Through the use of the invention, several significant advantages are achieved. These include reduced weight, reduced maintenance on rope and fewer bushed pivot points and the ability to raise the dipper closer to the machine boom sheave for material loading ease and clearance over trucks. 
     While in the foregoing specification a detailed description of an embodiment of the invention has been set down for the purpose of understanding, many variations in the details herein given may be made by those skilled in the art without departing from the spirit and scope of the invention.