US2957255A

US2957255A - Dragline bucket

Info

Publication number: US2957255A
Application number: US703915A
Authority: US
Inventors: Paul V Larsen
Original assignee: Esco Corp
Current assignee: Esco Corp
Priority date: 1957-12-19
Filing date: 1957-12-19
Publication date: 1960-10-25
Anticipated expiration: 1977-10-25

Description

Oct. 25, 1960 P. v. L ARsEN 2,957,255

DRAGLINE BUCKET Filed Dec. 19, 1957 VENTO/Q.'

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DRAGL'INE BUCKET Paul V. Larsen, Portland, Greg., assigner to Esco Corporation, a corporation of Oregon Filed Dec. 19, 1957, Ser. No. 703,915

3 Claims. (Ci. 37-135) This invention relates to a dragline bucket spreader bar assembly which is part of the hoisting chain structure associated with such buckets.

A dragline bucket to' which this invention can be applied has been described in my copending application, Serial No. 495,395, led March 21, 1955, now Patent No. 2,904,907 of which this application is a continuationin-part, and reference is hereby made to that application.

In the above identified application, a dragline bucket and its hoisting chain structure was described. The hoist chains were employed to connect the bucket to a hoist cable. Lower hoist chains were pivotally secured to opposite side walls of the bucket, and upper hoist chains were secured at their lower ends to the lower hoist chains and to the hoist block entraining the hoist cable at their upper ends. A spreader bar is provided that couples the upper and lower hoist chains and extends transversely across the bucket between the pairs of hoist chains. The spreader bar serves to space the lower hoist chains from the side walls of the ybucket and to prevent binding therebetween.

Also described in the above identified application was a novel structure for coupling the chains and spreader bar together which employed a U-shaped member or shackle. The coupling structure is not only important because of the tremendous stresses that are transmitted through it (it is to' be appreciated that dragline buckets are massive structures and weigh many thousands of pounds even when unloaded) but also because of the role the coupling plays in maintaining adjacent parts against undue wear and whereby failure, perhaps at a critical time.

A common drawback of the previously employed coupling structures lies in the fact that the pivotally-mounted shackle connecting the upper and lower hoist chains co'uld rotate suiciently so :as to permit the chain to kink, which resulted in stressing the links and causing bending and even breakage of the chain itself. In addition, the undesirable movement of the coupling shackle exerted possibly disabling stresses on the spreader bar as well as the adjacent chains, which stresses required the provision of unnecessarily heavy members to provide adequate resistance. The unpredictable nature, direction, and magnitude o'f stresses implicit in previously-employed couplings also seriously limited the variation in structural arrangements possible in couplings to those ascertained by long experience to be satisfactory. Thus, the toleration of one drawback produced hosts of others.

It is 'a general object of this inventio'n to provide an improved dragline bucket which overcomes the disadvantages and problems outlined above. Another object is to provide an improved coupling structure between the upper and lower hoist chains of a dragline bucket. Still another object is to provide an improved coupling between hoist chains in a dragline bucket ywhich also cooperates with a novel type of spreader bar assembly. Yet another object is to provide an improved dragline bucket assembly in which kinking of the associated hoist chains 2,957,255 Patented Oct. 25, 1960 is substantially avoided and which thereby eliminates the attendant stresses on associated and component parts.

A further object of this invention is to provide in the hoist chain structure of a dragline bucket a novel type of shackle which cooperates with the hoist chains and spreader bar to limit the tendency to kink of the hoist chains. A still further object is to provide in a dragline bucket assembly a coupling member in the form of a shackle having integral protuberances on the legs thereof that cooperate with projection means on the spreader bar to limit rotation of the shackle. Other objects and advantages of this invention can be seen as this specification proceeds.

This invention will be explained in conjunction with the accompanying drawing, in which- Figure 1 is a perspective view of a dragline bucket embodying teachings of this invention; Fig. 2 is a top viefw, partially in section, of the spreader bar portion of a dragline bucket; Fig. 3 is a side View in elevation of the spreader bar shown in Fig. 2 with o'ne end portion thereof being partially shown in longitudinal section; and Fig. 4 is a prespective view of one ofthe shackles associated with the dragline bucket and spreader bar shown in Fig. 1.

lIn the illustration given, the numeral 10 (seen only in Fig. l) designates generally a dragline bucket. Bucket 10 is equipped with side walls 11 and 12 and with a bottom wall having a plurality of teeth or points 13 projecting forwardly therefrom. Dragline chains 14 are connected to the side walls 11 and 12 at the forward ends thereof, and extending upwardly from the side walls are

lower hoist chains

15 and 16. A spreader bar 17 extends transversely across the bucket 10 and between the

lower hoist chains

15 and 16. Extending upwardly from spreader bar 17 are a pair of upper hoist chains 18 and 19 which, at their upper ends, are connected to a hoist block 20. A hoist cable 21 is connected to the block 20, and a cable 22 is entrained about a sheave in the block 20 and is connected to the .arch 23 of the bucket.

In the operation of dragline bucket 10, the

cables

21 and 22 and the dragline chains 14 are manipulated so as to cause the teeth or points 13 to bite into material lthat is being transferred into the bucket 10. Thereafter, the loaded bucket transports the ll toa suitable location and by .suitable manipulation of the various connections (all o'f which is well known), the bucket is pivoted so as to dump the load therefrom. As is also well known, the

lower hoist chains

15 and 16 are connected to the sidewalls 11 and 12 of the bucket at an olf-center location so that the bucket can be pivoted about the lower ends of the

hoist chains

15 and 16 to dump the bucket. The spreader bar 17 performs the function of spacing the

hoist chains

15 and 16 from the side walls of the bucket so that during lbucket manipulation, especially the dumping operation, there is no binding between the lower hoist chains and the walls of the bucket.

In Fig. 2, where an enlarged View of spreader bar 17 is seen, it is to be noted that spreader bar 1 7 includes an elongated tubular central section 24 with means at each end for coupling the upper and lower hoist chains asso'- ciated with each side together. In the illustration given, the central section 24 of spreader bar 17 is equipped with end portions 25 and 26 that are rigidly attached to central portion 24. Preferably, the end portions and central section are rigidly united by welding. In the specific illustration given, the end portions 25 and 26 are equipped with four equally spaced-apart key elements or stops 27 that serve to locate the end portions 25 fand 26 with respect to the tubular section 24 and thereby establish the pitch or distance between the mounting portion of the end castings .to be more specifically described hereinafter.

The tubular section 24 of the spreader bar may be formed from a conventional pipe, and, if desired, may be made so' as to have any other cross-sectional configuration than the tubular form shown. Further, the section 24 might be solid yrather than hollow, but ordinarily a hollow section is preferred because of the reduction in Weight aiforded thereby and, consequently, the more effective resistance to stress. In `order to give some indicatio'n of the massive character of spreader bar 17, the outer diameter ,of the pipe may be greater than eight and one-half inches' and the wall thickness might be threequarters of an inch. The Weight of the pipeV section may exceed ve hundred pounds. In addition to this, the end portions 25 and 26 contribute additional weight and are preferably of cast metal to achieve the conguration shown. Y

The end portions 25 and 26 of the spreader bar 17 are bifurcated .andv have spaced legs 28 and 29. Extending through the legs 28 and 29 provided in each end portion, is a pin 39 that is substantially cylindrical throughout its length but which has a square head 31. Pivotally mounted on each` of the pins 30 is a generally U-shaped shackle 32, and the shackle 32 is secured to the rst link 33 in each of the upper hoist chains 18 land 19. The legs of the U-shaped shackle 32 are spaced apart, and mounted therebetween and pivotally supported upon the pins 30 are the pear links or rst links 34Vof the lower hoist chains and 16.

As Vhas been stated before, the pin, at each kend of the bar, is cylindrical throughout substantially its entire length, and at one'end is received within a round bearing opening 35 extending through the leg 28 of each of the bifurcated spreader bar ends, and at the other end each pin 30 is supported within a square-shaped opening 36 in each of the legs 29. The pins are prevented from moving longitudinally in one direction relative to the legs 28 and 29 through engagement with a substantially unyielding member such as the bearing surfaces in the legs, or, as shown, by abutment with the shackle 32 as at 37 (seen in the left-hand portion ofFig. 3). f

The pins 30 are prevented from moving longitudinall in the opposite direction by the bearing or lock-plates 38 which slide into covering relation yover 'the heads of the pins through slots provided for that purpose by the flange elements 39 and 4t). These flange elements are eiective to inhibit up and down movement of the plates, as viewed in Fig. 3, while the enlarged or protruding stop members 41 (seen in Fig. 2) provided by each of lthe legs 29 at their ends, tend to limit longitudinal movement of the plates in a direction toward the outer ends of the legs. Each plate is rigidly held in position by a capscrew 42 that extends through the plate 38 and is threadedly received within a nut 43 locked within an appropriate bore or counter recess 44 in the leg 29.

In the use of the structure, the end portions and 26 of the spreader bar are inserted into the ends of the central section 24V of the spreader bar 17. A rigid uniting of the end portions 25 and 26 with the central section 24 is provided by welding the members together. Welding of the end portions and central section produces a homogeneous bar structure preventing the ends from rotating and further materially aids in enabling the bar to withstand the tremendous shock loads to which it is subjected.

The shackles 32 are threaded through the rst links 33 of the upper hoist chains 18 and 19, and the pear links 34 of the

lower hoist chains

15 and 16 are positioned between the spaced legs of the U-shaped'shackle members 32. The pins Vare then inserted through the openings in the legs 29, through the shackle 32 and the pear link 34 of each of the hoist chains and into the bearing opening in each of the legs 28Y of the bifurcated ends of the spreader bar assembly. The heads 31 are aligned with the mating openings 36 and are pressed thereinto. The lock-plates 38 are then moved longitudinally through the

recessed flange members

39 and 40 into the position shown in Figs. 2 and 3. Thereafter,

the capscrews are threaded into their respective nut 43 and are tightened against the plates 38 to lock the same in position. .Y A

It is apparent that the upper and lower hoist chains Yat each side of the bucket 10 are secured to the spreader bar 17 by means of pins 30. Pins 30 lie along the center line of spreader bar 17, and all of the forces exerted on the spreader bar 17 are directed thereagainst through the pins 30. Since these pins lie along the center line of the spreader bar, the forces applied thereto actr at points along the center line of the bar.

Each shackle 32 is equipped with an integral protuberance 45 (best seen in Fig. 4), which is located at the end of each leg or opposite to the base 46 of each U-shaped shackle 32. As seen best in Fig. 3, protuberance 45 includes a flat shoulder portion 47 which lies ou the longitudinal center line of shackle 32. The shackle 32 is so positioned on pin 30 as to have shoulder 47 facing inwardly of the spreader bar 17 Each end portion 25 and 26 is equipped with projection means 48 (best seen in the right-hand portion of Fig. 3) which cooperates with protuberance 45 to limit the arcuate movement of shackle 32 within an arc above spreader bar 17. In the illustration given, the arcuate movement of shackle 32 is limited to about iifty degrees, and very satisfactory resultsl are achieved under such conditions. The arc through which shackle 32 can pivot is designated by arrows in the right-hand bottom portion of Fig. 3 and designated by the numeral 49.

The projection means 48 which cooperateV to limit the arcuate movement of shackle 32, in the illustration given, take the form of a pair of lugs 5t) which are provided integral with end portions 25 and-26 between the legs 28 and 29. The lugs or ears 50 are spaced apart a distance approximately equal to the spacing apart of the legs of shackle 32. Each lug 50 is provided with a pair of planar surfaces atright angles to each other. One planar surface 51 is spaced from pin 30 at a distance just slightly in excess of the thickness of the annular portion of shackle 32 about the pin-receiving opening 52. Thus, inward deflection of pin 30 is limited by the abutment of Vshackle32 against face 51 of lug 50.

Lug 50 is provided with a second planar face 53 which, if extended, would pass through the axis of pin 30 and hence the pin-receiving opening 52 of shackle 32. Outward pivotal movement of the base portion 46 of shackle 32 rotates shoulder 47 of protuberance 45 into abutment with face 53 of lug 50 so as to restrict further outward arcuate movement of base portion 46 of shackle 32. Inward arcuate movement of shackle 32 is limited by the abutment of shackle 32 with an arcuate face 54 of each end portion, face 54, like lugs 50, lying between legs 28 and 29 of the end portion but above the longitudinal center line of spreader bar 17, as contrasted to the disposition of lugs 50 below the longitudinal center line of spreader bar 17 The provision of protuberances 45 in cooperation with lugs 50 limits the rotation of the shackle and, hence, the undesirable outward movement of the upper hoist chain which, in the past, resulted in kinking `of the chain. A kinked chain notV only imposes undesirable stresses on the various links, but could result Iin bending or breaking of the links. The limitation of the arcuate movement of the shackle also results in a reduction of the Vabrasion of the spreader bar and .the pear link of the lower hoist chain. The llimited movement achieved through the cooperation of the elements described above also promotes the reduction of undesirable stresses in the spreader bar assembly itself, since the initial stress applied by the chain on the spreader bar will always be in a substantially vertical direction, as contrasted to an initial stress induced by the kinked chain that might be more or less horizontal and thus place the spreader bar in an unusual state akin to tension.

,l-Iowever, through the operation of the novel structures hereinbefore described, the stresses present -in `a dragline bucket hoist chain and spreader bar assembly can be desirably limited to those of a nature which are more readily determinable than those of stresses occurring in prior art structures. A number of desirable advantages flow from this in that the operation of dragline buckets is made safer, more eicient, less subject to vexatious breakdown (it is to be appreciated that because of the size of the buckets even a faulty chain ordinarily results in substantial loss of time and money, since no ready replacements are usually at hand), and is made possible through the use of novel improved structures in other portions of the assembly which heretofore were thought inapplicable because of the `limitations imposed by shackle rotation.

It is also to be noted that a further new and desirable result is achieved through the assembly described hereinbefore in that the assembly permits the use of a materially lighter spreader bar than heretofore has been considered possible. The use of a lighter weight spreader bar, permitted here because of the avoidance of spreader bar-damaging stresses such as excessive bending m0- ments, further results in a spreader bar more highly resistant to damage from dropping on the top sides of the dragline bucket. Heavy spreader bars, as built in the past, because of their excessive weight, were prone to crack and split apart when dropped on the top of dragline buckets. The reduction of weight in the spreader bar assembly produced by the cooperation of the novel shackle hoist chain and spreader bar interconnection, results in the spreader bar not developing excessive bending moments. Helpful in this cooperation is the location of the shackle-supporting pin on the longitudinal center line of the spreader bar.

While in the foregoing specication an embodiment of the invention has been set forth in considerable detail for purposes of adequately describing the invention, it will be `apparent -to those skilled in the art that numerous changes may be made in the details set forth without departing from the spirit and principles of the invention.

I claim:

1. In a bucket structure of the character described having upper and lower hoist chains at each side thereof, a spreader bar equipped with bifurcated ends and an integral projection therebetween, a pin extending between the spaced legs of each bifurcated end, a shackle pivotally carried by each pin and being connected to the upper hoist chain, lower hoist chains each providing a rst link pivotally mounted upon the respective pins within the legs of the associated shackle, and an integral protuberance on each shackle for limiting the pivotal -rnovement of each shackle on said pin by engaging said projection.

2. In a dragline bucket having upper and lower hoist chains at each side thereof, a spreader bar structure extending transversely across said bucket, said spreader bar structure having bifurcated end portions providing spaced-apart legs, a U-shaped shackle member secured to each of the upper hoist chains and having leg portions interposed between the spaced legs of the bifurcated end portions, a pin extending through said spaced legs of each of said bifurcated end portions, said shackles being pivotally mounted on said pins and said lower chains being pivotally secured to said pins, said pins lying along the longitudinal axis of said spreader bar structure, protuberances on the legs of said shackles, and projection means on the end of said spreader bar between said legs yand providing an abutment surface below said longitudinal axis.

3. The structure of claim 2, -in which said projection means comprise a pair of lugs aligned with the legs of said shackle.

4. The structure of claim 3, in which each of said lugs is equipped with planar surfaces norlmal to each other, one of said surfaces lying in a plane extending through the axis `of said pin.

5. In a dragline bucket having hoist chains on each side thereof with a spreader bar coupled to said chains and maintaining said chains in spaced-apart relation, said spreader bar being equipped with bifurcated ends, a pin extending between the spaced legs of each bifurcated end, a shackle pivotally carried by each pin between said spaced legs and being connected to an upper hoist chain, integral protuberances on the leg portions of said shackle extending away from the base of said shackle, said protuberances providing yan inwardly-facing planar surface lying in a plane passing through the axis of said pin, and lug means on said spreader bar between the spaced legs of each bifurcated end, each of said lugs providing a downwardly-facing planar surface lying in a plane passing through the axis of said pin.

6. The structure of claim 5 in which each end portion of said spreader bar intermediate the spaced legs is inwardly and upwardly inclined.

7. In a dragline bucket having hoist chains on each side thereof and a spreader bar coupled to said chains and maintaining said chains in spaced relation, horizon- -tally and transversely-disposed pins in said bar adjacent the ends thereof and on the longitudinal center line of said bar for pivotally maintaining a shackle at each end of said bar, a shackle pivotally carried by each pin and being connected to a portion of one of said chains, and cooperating projection means on said shackle and bar effective to limit the pivotal movement of said shackle on said pin to within an arc disposed only above said spreader bar.

8. The structure of claim 7 in which the said arc is about 50.

References Cited in the tile of this patent UNITED STATES PATENTS 1,570,014 Stevens Jan. 19, 1926 1,882,147 Humphreys et al Oct. 11, 1932 1,962,291 Anderson June 12, 1934 2,001,924 Strong May 21, 1935 2,398,360 Daniels et all. Apr. 16, 1946 FOREIGN PATENTS 928,247 Germany May 26, 1955