Abstract:
A dragline bucket and method of operating a dragline bucket wherein a reverse V configuration of teeth is employed to eliminate slewing, i.e., sideways movement when encountering an off-center obstacle.

Description:
BACKGROUND AND SUMMARY OF INVENTION: 
     This invention relates to a dragline bucket and a method of operating a dragline bucket and, more particularly, to a bucket and method which avoids the problem of slewing by a novel tooth arrangement. 
     Dragline buckets are a species of excavating buckets which are filled by being dragged over the material or bank to be excavated by means of a dragline and then hoisted by means of a hoisting rope and thereafter dumped. Even as early as 1913, these dragline buckets were well known, see U.S. Pat. No. 1,050,838. A more recent detailed description can be seen in my U.S. Pat. No. 4,791,738. 
     Over all these years, buckets have slewed, i.e., shifted sideways, when encountering an off center load. This is most pronounced when keying such as cutting along a vertical sidewall or when encountering an off center boulder. I have solved this problem by arranging the teeth in a rearwardly extending V orientation, viz., the teeth project successively forward in proceeding from the longitudinal center line of the bucket toward the sidewalls thereof. 
     Over the long history of dragline buckets, this arrangement has not been used. The excavator of U.S. Pat. No. 2,060,867 had a reverse V configuration of teeth extending from the rear wall but performed no hoisting and dumping operation. Russian Patent 326,298 also had a reverse V configuration in a dredge but again did not perform the hoisting and dumping functions. 
     Although reverse V configurations of teeth art known, these have always been employed in buckets whose movement is controlled by dipper sticks or wheels and hence are not subject to slewing. Representative of this type of bucket are U.S. Pat. Nos. 3,791,054, 4,037,337 and Russian Patents 306,228 and 682,605. 
     A semblance of a forward V configuration is seen in a dragline bucket in U.S. Pat. No. 1,868,246. Other forward V configurations can be seen in U.S. Pat. Nos. 1,803,654, 2,629,945 and 2,660,323 but these, again, are all controlled against slewing by virtue of being rigidly mounted. 
     According to the invention, I arrange the teeth in a reverse V configuration on the lip of the bucket and advantageously at an angle of about 75° to about 80°, viz., the line connecting a given point on one tooth and a corresponding point on the adjacent tooth forming an angle of about 75° to about 80° to the longitudinal center line of the bucket. Further, I prefer to have the lip generally planar so that the teeth operate in the same plane. With this arrangement, slewing is substantially minimized by virtue of the tooth arrangement directing the obstacle-providing material toward the center of the bucket. 
     The invention is further described in conjunction with an illustrative embodiment in the accompanying drawing in which 
     FIG. 1 is a fragmentary somewhat schematic view of a conventional dragline bucket and associated prime move showing various features of operation; 
     FIG. 2 is a fragmentary top plan view of the apparatus of FIG. 1 showing a conventional bucket keying against a substantially vertical sidewall or bank; 
     FIG. 3 is a perspective view of a bucket lip featuring the inventive tooth arrangement; 
     FIG. 4 is a fragmentary top plan view, partially in section, of the forward portion of a bucket utilizing teachings of this invention; 
     FIG. 5 is a fragmentary side elevational view, partially in section of the bucket of FIG. 4; and 
     FIG. 6 is a fragmentary schematic top plan view showing the practice of the invention when the bucket encounters a boulder or the like. 
    
    
     DETAILED DESCRIPTION 
     Referring first to FIG. 1, the numeral 10 designates generally a prime mover such as a crawler machine equipped with a boom 11 and other rigging for the operation of a dragline bucket 12 seen removing material from a slope 13. The dumping mode is illustrated in the left of FIG. 1 as at 12&#39;. In conventional fashion, the bucket 12 is equipped with a hoist line 14, a dragline 15 and a dump line 16. 
     Now referring to FIG. 3 which shows in larger scale the forward end of the bucket 12, the numeral 17 designates a lip which normally is weldably secured to the remainder of the bucket, i.e., the bottom and sidewalls. For additional details of construction, reference may be made to my earlier U.S. Pat. No. 4,791,738 which details the interrelation of the side, rear and bottom walls and open front of a dragline bucket. 
     Still referring to FIG. 3, the numeral 18 generally designates teeth, five of which are seen disposed across the width of the bucket. These teeth may be of any acceptable construction but normally employ two-piece construction utilizing an adapter 19 and a point 20 secured thereto in temporary fashion by means of a locking pin 21. 
     As can be best seen in FIG. 4, the teeth 18 are arranged in a reverse V configuration, i.e., reverse insofar as the direction of advance of the bucket during excavation is concerned. Also as seen in FIG. 4, the teeth are arranged at an angle A of the order of about 75° to about 80°. More particularly, a line 22 connecting a given point on one tooth and a corresponding point on an adjacent tooth forms this angle A to the longitudinal center line 23. 
     The end teeth as at 18&#39; are secured to a portion of the lip equipped with a shroud as at 24 protecting the forward edge of the sidewalls 25 (see FIG. 3). The lip 17 extends forwardly from the bottom wall 26 (see FIG. 5) which bottom wall curves around to form the rear wall as can be appreciated from the showing in FIG. 1. 
     In operation, and with reference to FIG. 2, the bucket 12 is seen to be excavating or keying a portion of a substantially vertical wall 27. With the prior art buckets, it was necessary to &#34;crowd&#34; the bucket against the bank or wall 27 --as by positioning the boom off the bucket longitudinal centerline and over the bank. This is shown in FIGS. 2 at 11&#39;. In such a situation, the bucket &#34;slews&#34;, i.e., moves laterally, there being no constraint against this movement as there would be in a shovel dipper or other fixed bucket excavator. In contrast, the practice of the invention avoids the need for &#34;crowding&#34; because the force is distributed differently. More particularly, the most inboard tooth acts as a knife to slice rather than a plane which tends to slew. 
     Another advantageous feature of the invention is illustrated in FIG. 6 where the bucket 10 is seen encountering a boulder 28. By virtue of the reverse V configuration, continued pulling force on the dragline 15 causes the boulder to center itself as at 28&#39; and thus again avoids slewing of the bucket 
     A still further advantage accrues from the invention in connection with the bucket described in my earlier U.S. Pat. No. 4,791,738. A dragline bucket with straight-across teeth, when loading difficult material, will tend to tip up on its teeth if the material to load is difficult to penetrate. By the construction of my earlier patent, an increasing pull-to-tip characteristic is provided. By now utilizing the reverse spade lip of the invention, an even greater advantage is developed because, as the bucket tips, the three center teeth come out of a cut--not only putting all of the weight on the teeth but also putting all of the weight on the two corner teeth. This increases the penetration over a straight lip by approximately 150% in the illustration given and provides better stability because the bucket is positioned on the extreme outboard teeth, not tipping on the center teeth which may allow the bucket to fall sideways. 
     While in the foregoing specification a detailed description of an embodiment of the invention has been set down for the purpose of illustration, 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.