US2200315A - Excavator - Google Patents

Description

y 1940. R. s. WEIMER 2.200.315 I EXCAVATOR Filed June 5, 1937 2 Sheats-Shaet 1 Inventor figgfiwizd J. #2177227 .8) V

May 14, 1940.

R "s. WEIMER EXCAVA'IOR Filed June 5, 1937 2 Sheets-Sheet 2 altar i69 Patented May f Excavat on I Raymond S. Weimrf, 'Morris," lll. I 1 'a p i atmequnet,1937, sci-mine. 146,526

This invention relates to excavating apparatus, particularly oi the drag line typei i In conven tional drag line. equipment, the bucket is drawn irorn positions beneath the outer end of the boom elevated by the hoist line and moved to dumping position; Where the bucket moves down an in- H me during the loading "operation, the efficiency oi; the machine is lessened clue to the-tact that P11 bucket tends to, push the material-along aheadof it 'since'the material must flowre'l'at'i vely uphill into the bucket. There is a given incline dependent 'upon the friction angle or each material, up which such material will notflo'w. It

will be seen', therelfore, -that as the surface being ek cavated approaches su'ch angle, the operating efficiency or the machine is reduced.

@Wit h' eicavators of the steam shovel'type, the

scoop or bucket is moved away from the machine and this typeof excavator has certain advantages over'the conventional drag bucket type especially in taking on the load while the bucket" moves hrou'gh an upward curve or in a vertical plane.

tin the'p'resent improvement, the advantages of the shovel type excavator are obtained in that the scoop or bucket moves outwardly from the 'rri achinetoward a position under the point of the boom and thus, takes on its load' readily while eavin upwardly as w ell a's when moving horig iontally. In the shovel typeexcavator employing a boom'and dipper stick, a high digging eflicie'ncy 4o longer bQOm, thus increasing 'substantiallyithe effective excavating range oitheiaDDfilatus, or by" employing a scoop of greater load carrying (capacity. f

One object of the inventionis to provide an 45 'egcav'atorof the drag line type wherein the scoop or bucket moves outwardly from the machine and -islsustained in'excavating position primarily duringtheloading operation by a noveldragline arrangement supplemented, however, by a control 59 line which cooperates withthe drag line in varying the angle of the bucket, if desired,'during the loading operation and in supporting the bucket during the elevation and-transportation of the lo'a'd t'o' discharging positioni'p In e cavatin'gby means of "drag lines it genoward the center of the machine and it is then gsheave or sheaves l5 at its outer end, over which erally is desirable to maintain the bucket at a constant angle with respectto the surface being excavated. -In conventional drag line equipment, the bucket ordinarilycanfloscillate from a position wherein the bottom restson the material through 5 an arc cff'about sixty degrees about the point of the teeth-as a center, thus varying the angular disposition of the teeth and impairing the operating efficiency of theapparatus. l

It is a further object of the present invention, therefore, to provide means which reduce the frequency and amplitude of the oscillations of. the bucket and thereby effect stabilization of the same at effective digging positions Within angular limits.

In'the accompanying drawings,'where in an em bodimentof the invention is disclosed for the'purposeof illustration: j Fig. 1 is a broken elevation of drag line excavatin'g apparatus embodying the present invention, said figureillustrating the bucket orscoop in sev- 'er'aliofits operative positions; v A

Fig.z'2 is an enlargedvertical longitudinalsectio'n'lo'f the improved bucket and control rigging 'ina position intermediate its usual'load carryin position andload discharging position; 'Fig. 3 is a verticallongitudinal section of the bucket in load discharging'position; c, Fig. 4 is a perspective View showing a'single drag line and a single haul line but having branches, by means of which the force is applied tofthe bucket in the desired directions; and

5 is [a perspective view of a bucket illus- 'trating the attachment thereto of the various lines in-twin arrangement. ",I'n,the drawings, in indicates generally an ex cavating machine provided with a conventional 1 'fairlead l l over which a controlcable or cables l2 are trained and from which the same pass to a power operated, winding drum I3. The machine is also-provided with a boom [4 carrying a boom one" or more drag lines I 6 pass to a conventional power operati ng winding drum I"! carried by the machine. Q

'The' bucket h wn in F g; 4 and indicated gen-, '45 erally by the numeral I8 may be provided with teeth l9 at its excavating edge or lip and is provided with side walls 20 and a rear wall 2|, all of which walls preferablyfiare outwardly as illustrated. The drag line' I6, as shown in Fig. 4,!is

'attached'to-"the bucket by means of 'twolower flexibl br anches'such as chains lfia, the ends of the'branches being pivotally secured at 22 to the forward' ends'of the sidewalls 20; Upper branches 1'61?"arefialsofprovided and are attached at'points drag line i6.

the branches 16a.

I60 to the side walls 2G or bottom preferably to the inner faces thereof. The point of attachment of the branches 16a, lfib to IE is indicated at [601. The points I60 preferably are located rearwardly of and below the center of gravity of the normal load of the bucket which is indicated at CG. The center of gravity of a normal load of the bucket, which corresponds approximately also to the, center of gravity of the bucket when empty, lies preferably in a vertical plane between the two axes determined by points Hic'l'6c and 2222. Attached to the branches [6b are short convergent flexible lines Hie such as chains, which are at-: tached to the block of a sheave. 23, around which extends the control line l2 which, as shown in Fig. 4, is attached to upper rear portions of the bucket l8 by branch lines l2a.

In Fig l of the drawings, the bucket I8 is shown at A in the position which it may take when lowered by the control and hoist lines to start a loading operation. Position B illustrates the bucket as it is being'drawnoutwardly by the drag line it. In this position, it will be noted that the branch lines 1611 and IBb are taut, that the bucket is sustained in substantially horizontal position with the teeth of the bucket penetrating the soil and that the center of gravity CG of the bucket is in a vertical plane disposed between the points Hid and 22. The weight of the bucket tends to swing it downwardly or counter-clockwise as will be seen, while the resistance offered the teeth by the soil resists the forward movement of the bucket under the action of the The weight of the load acting at the center of gravity (CG) tends to swing the bucket counter-clockwise or rearwardly as it takes on its load. This movement tends to bring the bottom of .the bucket into substantial parallelism with the line of force exerted by the haul line l6, which tendency would be augmented should the teeth be deflected from the soil by a rock or otherwise be freed of the normal digging resistance. This approach toward the non-loading position is indicated by position C .of Fig, 1 wherein it will be noted that the bucket bottom has assumed a more acute angle with reference to this line of movement dueto the weight of the;

load. As the position shown at C is reached, however, the branch lines Hid will have become taut and the force of the drag line will, therefore, be applied to the bucketat axis |6c-l6c which is to the rear of the center of gravity of the normal load. The weight of the load, therefore, instead of tending to reduce the cutting angle tends to increase the forward tilting effect imparted to the bucket by the digging resistance during the time the drag line force is applied at the axis Hie-I60. Hence, should the teeth of the improved bucket be thrust from the soil by a rock or should the digging resistance at the teeth points be suddenly relieved while the hauling force is being applied at points 22 22, thus permitting the bucket to tilt rearwardly from the normal digging angle, the branches lEb-lfib immediately become taut and since they are located rearwardly of the center of gravity, the teeth are again forced into digging position. The return movement to such digging position is, of course,-limited at the angle wherein the haul line force is again applied by It will-be seen, therefore, that the oscillating .movement of the bucket about the axis lEc-lfic or vice versa and that the bucket,

digging angle.

In position B of Fig. it will be noted that the clockwise movement of the bucket is limited at angular positions wherein the points of the teeth and the pivot points 22 are aligned with the direction of force exerted by the-drag line l6. This therefore, is maintainedat an adequately stable,

of the bucket by gravity from effective diggingv angles whereas with the present improvements, the force exerted-by the drag line is applied to the bucket by the drag line branches at such points and in such directions as to effect stabilization of the bucket automatically within an effective digging are or segment.

It is apparent that as the angle between the bucket and the drag line l6 becomes greater, more of the pulling force of the drag line is transferred to the branches [6b and the load on the branch I 6a is reduced.- Note that in Fig. 1, position B, drag line l6 and branches l'6a are practicallyin a straight line, in which position branches I61), as in the case of an empty or only partially filled bucket, carry a relatively small portion of the force exerted by the drag line. In position C,the drag line IE3 and branches lfib are practically in a straight line due to the larger angle between the bucket and the drag line induced bythe weight of the load. Branches 1612 take an increasing amount of the force exerted by the drag line l6 as the angle of the bucket increases. bucket bottom can become parallel with the di-, rection of the drag line, branches lBb must receive all the force exerted by the drag line. position of the bucket cannot be attained, however, while the teeth are indigging position and adequate tension is applied to the drag line provided the center .of gravity is located forwardly of the axis lBc--l5c. This backward or counter- Such 1 Before the clockwise movement of the bucket, therefore, is

positively limited under the conditions just mentioned at the angle wherein the points l6cl6c Since which position the bucket bottom may be disposed at an angle of about sixty degrees to the plane of the excavated surface, it isseen that within the are or segmentdefined by those two limits of anngular movement, the bucket is controllable by the force app-lied thereto by the drag drag line branches.

line and the On either side of the said controlledsegment within which the bucket is maintained in digging position by the drag line, the bucket is controllable by'the control line l2. For example, from a position wherein the bucket rests on its bottom, it maybe tilted clockwise by the control line I! to a position wherein the teeth will penetrate the material as the drag line is taken in. The bucket, upon being drawn forwardly by the drag line .with the teeth embedded in the material, will seek a position within the digging segment referred to as the control line is released. It will be seen, therefore, that the bucket is con.- trolled automatically by the drag line within predetermined limits butmay be tilted beyond those limits by the control line when necessary.

In the event the center of gravity of a loaded 7 ing a loading operation, backward tilting 'of thev buck't is reduced due to the fact that upon initial rear" afd*tiltihg,'-the diggingresistance" on the offtlie tetlf is diminished 1 and the'c'enter of h moment of the haulingi-foice movesrrom buc'ket while digging.

It will be noted that the-arrangement' de 's'cri 'bed 'isi ih effect a three-point aittachmerihthe points';being the axes: I tic-I22 and point" [6d, the ilfst -twobeing rigidly 'heldapart due to their attachment 'tdthebucket itselfwhilefupoirit l6d is shifta'ble with respect tofsaid axes.

Tdkestrain tilting movement of the bucket from the excavating or digging angle under unusual' conditions, such tension may. be maintimes 'on the control line I2 as--wi1l prevent ex- H cessive counterclockwise movement of the bucket.

B y'taking in thecontrol line, the rear'end of the bucket can be elevated to cause the teethto maintain a, proper angle with respectfto thesurface beingfexcavated not withstanding the presence of fs'tones or other hard formationswhich, may

tend to deflect thebucket from proper digging mam q 2' "''W] 1ile the threepoint attachment means' above described tends to stabilize the bucket through out its loading range duringnormal operation, it

is attirnes' desirable .to effect oscillation of the bucketfabbut. the points .off the teeth as an axis orabput.ithe axis 22 or axis Hie" or about the point ISd in. order'to provide aprying'action in the ma't erial being cut; This may be accom- 40 i ished-by applying tension to' line which vates'the rear end of the bucket and then releasing such tension. This may be repeated as the bucket moves throughout the loading range andaswill be seen, will facilitate breaking loose 5 hard material in which the bucket may be ope a n It 'll be apparent, therefore,-thatthebucket n" bf'operated without usingthe upper drag l branches Nib for balancing the bucketif adeguate'tension is maintained'on the control line retairfthe bucket in proper excavating posifli l -loweverjf the lifting effect exerted on r of the bucket by the control line is in 1 i n to the weight'and load thrust of the u ket, which thrust has a forward component which jtendsto force the teeth'into the material Min /e cavated, .This increases the digging eff,ic;i ency of the bucket, as will be seen, and hence, duiiingnthe digging operation, tension is applied to the control line [2 preferably onlyiwhen necessary;..suchas in restoring .thexteeth to the earth penetrating angl'eafter expulsion by a rock, obi-the dike, or when a sharper angle is necessary tel 5 dueto'the'natureof thematerial being excavated.

ra -As-the. bucket approaches the end of its upwardmovement through the loading range, the operatorapplies-tension to control line l2 to retain the bucket in the load carrying position such 70 asl is in'di'cated at D in Fig. "1. In this carrying orj-transportihg'position of the bucket, it will be noted; sufficient tension has-been exerted on line l 2yto" i'et'ain the bucket .in substantially horizont'alposition, the bucket being supported in that osiueniby the branehes isa, the control line a aoogs is counter-clockwise "angular oscillation of the Hand branches [2a and" by the forward portions of the 'branches lfib andthe'branches l6'e." The boom and loaded bucket may 'now' be swung to load discharging position over" the dumping place for dischargingthe load. In 2, the bucket is shown in a position intermediate the position D of Fig. l and the discharging position of Fig. 3. By releasing the tension'on control line l2; the rear end of the bucket will be lowered. During this unloading movement, the weight of the bucket which has been sus-' pended 'by'the branch line 16a and-the control line and its branches will be shifted to line 16b and the center of gravity will move counterclockwise to the left of the pivotal axis deterniinedby-th'e point" Ito whereupon the bucket is self-dumping' and moves by gravity to the load discharging position' shown in Fig. 3.

- It will be noted that the bucket is free to swing beyond the pendent position shown" in Fig. 31 In fact, it'may swing well beyond that 'or until the bottom reaches approximately the dotted'line position indicated. The material of the load flowing over the inclinedrear wall also tends to swing the bucket beyond the full line. position of i Fig. 3, thus enabling the bucket to shed or clear its entire load. As the bucket approachesthe full lineposition of Fig. 3 during the counter-block; wise movement, the upper edge or lip of the bottom will strike chains [6b,ijarring the bucket and tending to free it of any clinging portions of theload. This facilitates clearing the bucket,

even' when wet and sticky materials are being handled and improves the operating efii ciency of the apparatus. The bucket comes to rest in the full position of Fig.3 wherein the bottom-is'inclined to the vertical and the rear wall is sharply inclined, thus precluding the retension ofaany substantial portion of the load. The bucket is righted'by hauling in the control line l2, and by simultaneously paying out the hoist line [6. I The bucket'may .be returned to the position A shown in Fig; lfor'the' nextloading operation.

" As stated above", th'econtrol line l2 and the drag line it maybe butsingle cables having the chain branches above described. However, if desired, these lines may be twin lines arranged in parallelism as shown in Fig. 5. Thus, the control lines l2 may each be provided with a sheave 23 and each attached to-the rear upper I portion of the'bucket. The drag lines I6 may have the upper and lower branches 16a and Nib" to which are attached the sheaves 23 by the short lines lfie the upper and lower branches being connected to the bucket l8 at points I60 and 22', respectively. In'other respects, the ap+ paratus-will correspond-to that above described except that the boom will carry two sheaves cor-1 responding to sheave A5 of Fig. l and the winding drums will by known means accommodate the twin lines instead of the single lines. a V i The excavating apparatus above described opcrates with improved efiiciency when the scoop or bucket moves at an angle to the horizontaltoard the .point" of the boom. In Fig. l, the surface of the material to be excavated is shown as approximately forty-five'degrees but by raising or lowering the boom, like efficiency ,may be maintained where the surface lies atgreater'or less'angles than that shown. It will be noted also that in the region well'under" the boom, the bucket will also dig as itmoves horizontally outwardly; or outwardly and downwardly as indi dated by the curved excavatedareaadjacent the machine shownin' Fig. l;

Due to the spacing of the pivotal axes l6 and 22 preferably rearwardly and forwardly respectively of the center of gravity of the bucket, the force applied by the drag line branches resists the weight moment of the bucket and the load which tends to swing the rear end of the bucket about the ends of the teeth in a counter-clockwise direction as viewed in Fig. l, and also moves the bucket forwardly with the teeth at the desired digging angle. It is only when the material being excavated is of such character that it tends to expel the teeth from digging position that the control line need be employed to increase the digging angle by elevating the rear end of the bucket.

Comparing position A of Fig. 1 with the position of the bucket in Fig. 3, it will be seen that it is swingable on its horizontal axes through an arc of approximately one hundred eighty degrees. Thus, in the load discharging position, the bucket hangs pendent with the bottom and rear walls favorably inclined for shedding all por-. tions of the load, while in position A, the teeth are lowermost and may in fact be forced into the earth as by the lowering of the bucket into that position by the control line, thereby enabling the bucket to operate efficiently at levels beneath the base of the machine. The teeth may also be forced into the material at any point on the digging plane by holding drag line "5 and taking in on control line I2, thus lifting the bucket clear of the material; then by releasing the control line I2, the bucket will enter the material teeth first.

By shortening the branch lines [6b, the bucket will be tilted more in a clockwise direction during the digging operation than is shown in positions B and C of Fig. 1. Such tilting increases the cutting or digging pitch of the teeth with respect to the surface of the material to-be excavated but the relative lengths of the branch Isa and I6?) must be such that the center of gravity of the loaded bucket can move to the left of the axis |fic|6c (Figs. 2 and 3) to effect completely the dumping action as the control line I2 is released.

I claim:

1. Excavating apparatus comprising power means, a boom, a branched drag line carried by the point thereof and operable by said means, a bucket attached to the branches of said line 'on axes disposed forwardly and rearwardly of a vertical plane through the center of gravity of the bucket for sustaining the same at a digging angle with respect to the plane of the material being excavated as the bucket moves through the loading range thereof, and a control line attached to a rear portion of the bucket and cooperable with said branches for sustaining the bucket in load carrying position as the same passes beyond the loading range towar the point of the boom.

2. Excavating apparatus comprising a boom,-

a drag line carried thereby, a bucket, front and rear branch lines attaching said bucket to said line on axes disposed rearwardly and forwardly of the center of gravity of the bucket for sustaining the same at a digging angle with respect to the surface being excavated as the bucket moves through the loading range, and a line at tached to said bucket rearwardly of said center of gravity thereof for cooperation with said branches for sustaining said bucket in load carrying positions as the same moves beyond the loading range and controlling the dumping thereof. I 3. Drag line apparatus comprising a lboom a bucket, flexible supporting lines suspended from the boom and attached to the bucket at points so located forwardly and rearwardly of the center of gravity of the loaded bucket asto provide two axes uponwhich. the bucket turns successively from load carrying to load discharging position, and a controlline cooperating with said supporting lines for sustaining the bucket in load carrying position and controllingthe loaddischarge movement of the bucket about the first axis. v

4. Excavating apparatus comprising a boom,- a

drag line suspended therefrom, a tiltable bucket,

branches attaching said bucket tosaid line'on axes forwardly andrearwardly of the centerof gravity of a loaded bucket, said axes being so related to said center of gravity that the bucket when suspended by'said drag line tends. totilt rearwardly insuccess'ion on said front and rear axes respectively to load discharging position,

and a control line for controlling the dumping actionof the bucket and cooperating with said branch lines for' supporting the bucket whe elevated in load carrying position.

5. The combination with a drag bucket having front and rear drag line attaching means secured to said bucket on axes so located respec-.

tively forwardly and rearwardly of the center of gravity of anormal load of the bucket as to effect control of. the digging angle of the bucket during loading operations, and a controlv line see cured to rear portions of the bucket whereby variation in the digging angle of the bucket can be effected independently of said haul line at taching means during loading operations and cooperating with said haul line attaching means for supporting said bucket in load sustaining positions during elevation and transportation thereof.

6. Drag line apparatus comprising a boom, a

common haul and hoist line carried thereby and depending from the outer end thereof, a drag bucket having an inclined rear wall over which the load is adapted to be discharged when the bucket is tilted to dumping position, haul line attaching means pivotally securing said haul and hoistline to forward-portions of the bucket for moving the latter toward said end of the boom during loading operations and enabling said.

bucket to tilt'about the pivotal axis to dumping position, asheave carried by said haul line attaching means above the bucket, control "line tensioning means positioned adjacent'the base of the boom, and'a control line operatively at? tached to the rear of said bucket and to said tensioning means and passing around said sheave for cooperating with said haula'ndhoist line when the control line'is tensioned by said tensioning means for varying the digging angle of the bucket during loading operation and supporting the bucket in load sustaining position during elevation and transportation, and permitting said bucket to tilt about said pivotal axis upon release of tension on said control line while the bucket is suspended by said haul and hoist line.

'7. Drag line, apparatus comprising a boom, a line depending from the outer end thereof for hauling av drag bucket to load the sameand for elevating such bucket, a drag bucket having an inclined rear wall over which the load is adapted to be discharged when the bucket is tilt-edto dumping position, line attaching means securing the bucket to said line for hauling said bucket toward said outer end of the boom during loading operations, said attaching means being secured to the bucket on an axis whereby the bucket tends to tilt rearwardly to load discharging position when elevated. by said line, a sheave carried by said attaching means, and a control line secured to the rear of said bucket and passing around said sheave and cooperating with-said line attaching means for supporting said bucket against tilting rearwardly from load sustaining position during elevation and transportation means therefor secured to the bucket on an axis normal load whereby the bucket tends to tilt rearwardly when elevated by said line, a control line, and control line attaching means secured to the bucket at the rear of the center of gravity thereof, a sheave carried by said first mentioned attaching means and engaging said control line for supporting said bucket in load sustaining position during elevation and transportation thereof by said first mentioned line' and enabling said bucket to tilt rearwardly about said axis and to load discharging position when released by said control line.

RAYMOND S. WEIMER.

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