US1518757A - Excavating mechanism - Google Patents

Description

Dec. 9, 1 2 1,51s,7s7

J. C. REID, JR

EXCAVATING MECHANI SM Filed April 5, 1923 5 Sheets-Sheet J CLOsNG LINE.

HOLDING 045 fl a A INVENTOB Dec. 9, 1924- J. C. REID. JR

EXCAVATING MECHANISM Filed April 5. 1923 5 Sheets-Sheet 2 T/vvE/v T R Jhz-zzca 0 E615] .Tlf

Dec. 9, 1924- 1,518,757

J. C. REID, JR

EXCAVATING MECHANISM Filed April 5, 1923 5 Sheets-Sheet 3 INVENTOFf $222615 Cf fiaicjh y flTTofi/vfi g DEC- 9! J. C. REID, JR

EXCAVATING MECHANISM Filed April 5, 1923 5 Sheets-Sheet 4 3 J I. .-l.ll WW my m WwW /W/A/M Dec. 99

J. C. REID, JR

EXCAVATING MECHANISM Filed April 1923 5 Sheets-Sheet 5 Patented Dec. 9, 1924.

UNITED STATES JAMES C. REID, JR., OF CLEVELAND, OHIO.

EXCAVATING MECHANISM.

Application filed April 5, 1928. Serial No. 629,958.

To all whom it may concern:

Be it known that I, JAMES C. REID, Jr., a citizen of the United States, and a resident of Cleveland, county of Cuyahoga, and State of Ohio, have invented a new and useful Improvement in Excavating Mechanism. of which the following is a specification, the principle of the invention being herein explained, and the best mode in which I have contemplated applying that principle, so as to distinguish it from other inventions.

The present improvements, relating, as indicated,-to excavating machinery, have more particular regard to the provision of means for operating a clam shell bucket or like excavating device, wherein such bucket is forcibly crowded down onto the material to be handled. Ordinarily the weight of the bucket is relied on to hold or crowd the same in en position against the material to be han led and the effect of such Weightis reduced by the tension on the closing line to the bucket for when this is drawn in, it tends at the same time to lift such bucket, despite whatever means may be used to minimize such tendency.

I have found, however, that by employing a supplemental or crowding boom, in ad'dltion to the main support from which the bucket is hung, the tension of such closing line to the bucket may actually be employe to force the latter into its work. More or less incidentally to the use of such crowding boom 1 have devised a novel arrangement of operating means whereby the action of forcing the bucket against the material may gI on during a part of the closing of the hue ct and yet not interfere with the lifting of the bucket when closed.

To the accomplishment of the foregoing and related ends, the invention, then, consists of the means hereinafter fully described and particularly pointed out in the claims, the annexed drawings and the following description setting forth in detail certain mechanism embodying the invention, such disclosed means constituting, however, but one of various mechanical formsin which the principle of the invention may be used.

In said annexed drawings Fig. 1 is a side elevation of my improved excavating mechanism mounted or installed on a typical support; Fig. 1 is a. transverse vertical section of a portion of the support, the dam of such section being indicated by the line a-u, Fig. 1; Fig. 2 is partly a side elevation and (partly a central section of that portion of sai mechanism which I have designated as the crowding boom, the planeof the sectioned portion of said boom being indicated by the line bb on Fig. 3 and by the line c0 on Fig. Fig. 3 is a top plan view of one of the two principal component members of such crowding boom, viz, the upper one, as shown in Fig. 2; Fig. 4 is a transverse vertical section of the support for and an elevation of the rear end of such component, the plane of the section being indicated by the line 44, Figs. 2 and 3; Fig. 5 is a top plan view, similar to Fig. 3, but showing the lowermost component of the boom as viewed in side elevation in Fig. 2; Fig. 6 is a transverse vertical section of the support for and elevation of the rear end of said last mentioned component, the plane of the section being indicated by the line 66, Figs. 2 and 5; Fig. 7 is a side elevation of the bucket in closed position, corresponding with that shown in the upper portion of Fig. 1, but on a larger scale and illustrating additional details; Fig. 8 is a front elevation of such bucket as shown in Fig. 7 Fig. 9 is a side elevation of the operating mechanism for said bucket, as viewed in a direction opposite to that shown in Fig. 7; Fi 10 is a longitudinal central section on a stifi larger scale of such bucket operating mechanism, the lane of the section being indicated by the line 1O-10, Fig. 8; Figs. 11 and 12 are transverse sections showing details of such mechanism, the planes of said sections being indicated by the lines 11-11 and 1212, respectively, on Fig. 10; Fig. 11 is a plan View of certain of the parts appearing in Fig. 11:; Fig. 12 is a sectional view taken on the same plane as that of Fig. 12, but looking in the opposite direction i. e. in that of the arrows 12.12, Fig. 10; Fig. 13 is another longitudinal central section of said operating mechanism, similar to that of Fig.

10, but taken on the plane indicated by the line 13-13, Fig. 8; Figs. 14 and 15 are transverse sections of said mechanism, the planes of which are indicated by the lines 14--14 and'1515, respectively, on Fig. 13; Fig. 16 is a transverse section of the bucket head taken in the plane indicated by the line 16-16, Fig. 9, such section being on a somewhat largerscale than said Fig. 9; and Fig. 17 is a front elevation of the bucket head on the same scale as Fig. 16.

As indicated, my improved construction of excavatin mechanism consists of an excavating buc'et A, shown as of the clam shell type, a crowding boom B, and a suitable structure C, which I shall hereafter refer toas the crowding boom guide. for supporting the latter. So far as means are shown for carrying such crowding boom guide and for affording a means of suspension for the bucket A, it will be understood that such means are merely typical. Thus in Fig. 1 said guide C is illustrated as forming in effect a part of a turntable platform 1 mounted on a railway truck 2. and the bucket A is suspended from the outer end of a boom 3 pivotally mounted on said platform 1, all substantially as in a standard locomotive crane. It has not been deemed necessary to illustrate my excavating mechanism in connection with other supporting means such as are frequently used for carrying bucket mechanisms of the general type in hand, such as an overhead bridge, derrick, barge or the like, since in all of these the construction and relation of parts of present interest will remain substantially unchanged.

Since the operation of such parts of present interest is not affected by a chan e in the point from which the bucket is suspended relatively to the crowding boom guide C, the means' for raising or lowering boom 3 and forrotatin the platform 1 will not be described other than to note that such raising and lowering means include a cabled, as shown in Fig. 1. For the same reason, the means for operating the bucket, in so far as these include the usual closing line or cable 5, holding line or cable 6, corresponding pulleys or sheaves 7 and 8 in the outer end of boom 3. and winding mechanism 9 for said cables mounted on platform 1,'will not require further descripion.

The crowding boom B, as illustrated in detail in Figs. 2, 3 and 5, is in reality composed of two boom-like members 10 and 11 that are pivotally interconnected at their outer ends by'means of a pin 12 and are guided at their inner ends in corresponding channels 13 and 14 that form parts of.

crowding boom guide C. As .a matter of fact, as shown in Fig. 1', two such channels are provided thus to guide the inner end of each of said boom parts 10' and 11. each such Part being of elongated A form built up suitable structural shapes as shown to provide the necessary strength and rigidity The channels of each pair 13, 13, and 1 14, are disposed with their channel faces directly towards each other and are'adapted to receive, and form a rolling guide for rollers 15, 15, and 16, 16 on the outer ends of shafts 17 and 18. rotatablv mounted in the rear ends of said boom parts and 11, respectively. It will be understood, of

awyer course, that said pairs of channel guides are mounted in parallel relation both with respect to each other and as between the two pairs. Alongside and in effect integral with each channel 13 is a rack 20 and a similar rack 21 is disposed alongside each channel 14, said, racks being adapted to be engaged by pinions 22, 22, and 23,. 23, fixed on shafts 17 and 18, respectively.

As a result of the interengagement of these racks and pinions, it will be seen that movement of the rear ends of the boom parts 10 and 11 along the channel guides may controlled by controlling rotation of said shafts 17 and 18. and that by locking both such shafts against rotation, the crowding boom B, composed of the two parts 10 and 11, may be locked in any desired angular position relatively to the crowding boom guide C For the purpose of thus controlling the movement of the rear end of boom part 10 along channel guides 13, there is fixedly mounted on shaft 17 a ratchet wheel 25 and on shaft. 26 located in said boom part inst forwardly of said shaft 17 is oscillatorily mounted a dog or pawl 27 disposed toengage said ratchet wheel and normally held thus in engagement by means of a compression spring 28. -Oscillatorily mounted on said shaft 26 adjacent pawl 27 is a double arm rocker 29 that carries a lug 30 so disposed as to press against and withdraw said pawl from such engagement with ratchet wheel 25 whenever said rocker is oscillated in a counter-clockwise direction. as shown in Fig. 2. Normally a tension spring 31 connected with one end of said rocker 29 serves to hold the same inoperative: line 32, however, connected with the opposite end of said rocker. is adapted to operate the same against the tension of said spring 31 so as to withdraw the pawl 27 and thus allow the shaft 17 to rotate freely.

For the purpose of controlling the movement of the rear end of boom partll along corresponding channel guides 14, means substantially identical with those 'just described for controlling the movement of the rear end of boom part 10 are employed. Thus, as shown in Figs. 2 ands"), a ratchet wheel 35 is fixedly mounted on shaft 18 and a co-operating dog or pawl 36 is mounted on a shaft 37 located just forwardly of said shaft 18, said pawl being normally held in engagement with the ratchet wheel by means of a spring 38 as before; Oscillatorily mounted on said shaft 37. adjacent pawl 36 is a double arm rocker 39 provided with a lug 40 dis sed to engage with said'pawl- 36 and with raw the same against said spring 38, said rocker being normally held inoperative by means of a tension spring 41 connected with one end thereof, while a line 42 connected with the opposite end of said tit) rocker is adapted to oscillate the same in a clockwise direction, as shown in Fig. 2, and thus to withdraw said pawl.

Lines 32 and 42 are in fact merely parts of a single line that passes around a floating sheave 43'located near the forward end of the crowding boom. the sheave block being attached to one end of a line 44 that is guided around a sheave 45 mounted on the pin 12 whereby the forward ends of the two parts of the crowding boom are pivotally secured together. The upper part 10 of said boom is formed with a. forked extension 46 that projects beyond such pivot pin 12 and carries a fixed sheave 47 and a rotatable double sheave or drum 48, 49. co-axially mounted on a pin 46*. To the middle sheave or drum 48 is attached the other end of said line 44, while to the fixed sheave 47 and the outer portion 49 of the rotatable double sheave are attached the lower ends of two cables 50 and 51 (shown as chains, see Fig. 1) which may be respectively designated as a crowding and an unlocking cable. The other ends of said chains are connected with suitable operating mechanism in the head of the bucket A proper, as will now be de scribed. Itwill be noted, however, that rotation'of the drum portion 48, to which the forward end. of line 44 is attached, in a counter-clockwise direction, as viewed in Fig. 2, will serve to wind up such line and thus to place lines 32 and 42 under tension, sheave 43 serving as an equalizer. This is what occurs, as will be later described, when the unlocking chain comes up taut and rotates sheave 49. The effect of such tension on lines 32 and 42, as previously explained, will be to release-the corresponding pawls 27 and 36 with the result that the rear ends of the respective parts 10 and 11 of the crowding boom are left free to move along their respective guide channels 13 and 14.

Cables 50 and 51 are wrapped approximately. half around the respective sheaves 47and' 49 and dead-ended and said sheaves -are made of the same diameter so that the relation of the'crowding cable tothe unlocking cable may not vary as the boom is raised or lowered with the'bucket. l

The two halves or trays 55 of bucket A are hung from the bucket head 56 by means of links 57 in the usual manner, except that such links are provided at their upper ends with inter-engaging teeth 57 (Figs. 7 and 9) that serve to eliminate side-sway and thus keep the head of the bucket in normal position at a right angle to the vertical center line of the bucket. The closing of the bucket 'isthen etfected by means of loops 58 of wire rope'or equivalent cable between the bucket head and sheaves 59, one on each side suitably attached to the corresponding hinge joint 60. Said cable loops 58 are in effect continnations of the closing line 5 which, af-

56. As best shown in Fig. 10. such looped cable portion 58 passes several times around said drum 63 and is then dead-ended. while a separate piece of cable that goes to form the companion loop 58 is secured at one end to the drum, and after being passed several times around it is lead off over another guide sheave 65, around the corresponding sheave 59 on the bucket hinge. and thence passes up to a drum 66 that is mounted on the same shaft 64 in the bucket head as is drum 63. Virtually the loops 58 may be regarded as constituting an unbroken continuation of the closing line the only purpose in breaking such line where it passes around drum 63 and separately attaching the broken ends to such drum being to give a fair lead to the line when the bucket is closed since at this time the sheaves 59 attached to the bucket hinges are drawn close in to the head of the bucket.

Made integral with drum 66 is a drum 67 to which is attached the upper end of crowding chain 50, the lower end ofwhich, as previously described, is connected with the fixed sheave 47 in the outer end of the crowding boom. Inasmuch as during the closing of the bucket said crowding boom is designed to be locked in position. i. e.. its outer end is prevented from rising, any tension in the closing line 5 is transmitted through the loops 58 and drums 63 and 66 to said drum 67 which is thereby actuated to draw chain 50 taut and thus force the bucket into its work. The greater the resistance which'the bucket trays encounter in entering the mate rial, the greater becomes this crowding action; in fact. if the bucket trays should be unable to enter the material. the crowding force would be limited only by the power-of the engine or by the rigidity and ultimate strength of the materials entering into the" ably mounted on shaft 64 between drum 63 rotated in conjunction with drum 66, in forcing the bucket downward, the locking ratchet 71 and drum 7 O, to which the unlocking chain is attached, will be rotated an equal amount, so that the relation between the unlocking chain and the crowding chain remains the same during this part of the o ration. Referring more articularly to igs. 10 to 12, inclusive, it Wlll be noted that an inwardly directed lug 75 is attached to an interior wall ofdrum 63 in position to coact with a lug 76 mounted on one end of a trip shaft 77 that is reciprocably but normally non-rotatablv mounted in the bodyof drum 70, said shaft lying parallel with the axis of said drum, i. e., with shaft 64. When the bucket is resting open upon the material andis ready to close, the face of said lug 75 has an angular advance ahead of the face of lag 76 determined by the design, being 40 degrees in the construction as illustrated, and as a result when drum 63 is rotated during the closing of the bucket, being driven by the several turns of the line or cable passing around it, the lug 75 after rotating through 320 degrees comes into contact with lug 76.

Up to this point the unlocking chain drum 70 has been rotated in unison with the crowdin chain drum 67, it being driven, as previously explained, through the engagement of lug 72 with lug 73, and the amount of this rotation of drums 67 and 70 depending upon the extent to which the bucket has been forced into the material. However, upon engagement of lug 75 with lug 76- on trip shaft 77, said drum 70 will be driven from drum 63 and be advanced ahead of drum 67. In Fig. 15 the parts are shown in the relative positions they occupy after drum 70 has been thus rotated 20 degrees ahead of drum 67 The unlocking chain drum 70 continues thus to be rotated by drum 63 ahead of the crowding chain drum 67 until the unlocking chain is brought up taut, with the final result that the inner sliding or rolling end of the crowding boom is released, as has been described. Since thereuponthe weight of the outer end of the crowding boom has to be carried by the unlocking chain, any further rotation of said drum 70 would raise the end of said boom towards the bucket head. To prevent this, the trip shaft 77, through the medium of which said drum 70 is thus driven by drum 63, is automatically caused to disengage lug 76 from lug 75. The means for accomplishing this result include a roller 80 on an arm 81 disposed to engage a face cam 82 on the crowding chain drum 67, such engaging being timed to occur net as soon as the unlocking chain drum 0 has been rotated sufliciently, in advance of said drum 67 to unlock the crowding boom. The result of engagement of roller 80 with cam 82 is to force trip shaft 77 lengthwise sufficiently to disengage the clutch aws 83 at its opposite end, which normally prevent said shaft from rotating, said jaws being held in engagement by means of a compression spring 84 that surrounds the shaft and is housed in the body of drum 70. The trip shaft being now free to rotate, lug 75 will force lug 76 over and clear it and the rotation of the'unlocking chain drum 70 ceases. It will be understood that the operation just described may be timed to take place at any predetermined point during the closing of the bucket, for example, when the latter is two-thirds closed. Beyond this point, the closing of the bucket will continue to completion without reference to the self crowding feature.

In order that the crowding boom ma be unlocked without causing the raising o the boom through the free rotation of the crowding chain drum 67, the device, shown in detail in Figs. 13, 14 and 15, is provided for interlocking drum 67 and thus drum 66 with the bucket'head. Such device comprises an oscillatory lock shaft 85 that passes through the integral body of drums 66 and 67 and carries at its-inner end a short radially projecting lever arm 86 provided with a roller 87. The latter is adapted to travel along an inwardly directed cam 88 on drum 70, being held in contact with said drum by means of a compression spring 89 that coacts with a radial lever arm 90 mounted on the outer end of the shaft 85. This arm 90 is continued to form a dog 91 that is disposed. to engage with the teeth. of a lock ratchet 92 on the head of the bucket. The

cam 88 it will be noted will permit such locking engagement between dog 91 and ratchet 92 to occur when, as shown in Fig.15, the drum 7 0 has been rotated 20 degrees ahead of drum 67 For the urpose of restraining the unlocking chain rum 7 0 from rotatin backwardly and so lowering the end of t e crowding boom when trip shaft 7 7 is released, as the result of which the boom would again become looked, a dog or pawl 95 is provided to engage the locking ratchet 71 (see Figs. 7 an 8). Operation of this pawl is controlled b asystem of interconnected links 96 andv 9 to the first of which the holding line is attached, while guide sheave 61, under which closing line 5 passes, is attached to the other such link. These links are so arranged that as lon as either the holding line or the closing ine is taut, said links keep the position shownin Fig. 8 wherein the do 95 is left free to engage the ratchet 71. H ence the filled bucket may be raised or lowered at will, the crowdin 'boom remaining unlocked for during t ese operations one of the lines 5 and 6 must be taut.

As best shown in Fig. 16, the links 96 and 97 are formed to pass'down through slots 98 in the head 56 of the bucket, where fixed pins 99 are passed through their ends and serve to limit the upward travel of such links. The holding line is attached to a pin 96 passing through links 96 and this pin carries the weight of the bucket and its load at such times as this weight is on such line.

Integral with locking ratchet 92, which is fixed in or forms a partof the head of the bucket, are two circumferentially spaced lugs 100 that are adapted to engage an oppositely disposed lug 101 on drum 66, as shown in Fig. 17. The action of the foregoing lugs is to limit the travel of said last mentioned drum so that the outer end of the crowding boom cannot be lifted far enough to come into contact with the bucket head. In the construction as illustrated, such crowding effect is designed to proceed during 163 degrees rotation of the crowding chain drum 67 which will permit. a predetermined downward motion of the bucket into the material to be excavated, suflicient for a bucket of the particular size in hand. The crowding effect of boom B is not valuable during the latter art of the closing of the bucket since at this time the trays 55 are in a position approximating the horizontal and the crowding etl'ect cannot increase the digging power of the bucket as much as at the point of entry into the material. Should the latter allow the crowding of the bucket to proceed so rapidly that the end of the crowding boom makes its full travel with reference to the head of the bucket, then the lug 101 will come in contact with one of the lugs 100 and the crowding effect will cease. However, when the crowding boom has been unlocked. its end will be raised a short distance by the un locking chain as the drum 70. to which the latter is attached. is rotated through the 20 degrees required to disengage the clutch jaws 83 that normally lock the trip shaft 77, as previously described. The lug 101 on drum 66 also limits the downward motion'of the end of the crowding boom with reference to the head of the bucket.

In case the material being handled does not offer much resistance and all of the crowding action takes place during the early part of the closing of the bucket and drum 66 has been stopped by engagement of lugs 100 and 101, as has just been described, then as the trays of the bucket close, the bucket mav bury itself further into the material. It might be supposed that under-these conditions the distance between the end of the crowding boom and the bucket would be shortened and the unlocking chain thus rendered inoperative. It will be noted, however, that when the crowding boom is locked,

it is only locked against rising due to the direction in which theteeth on the ratchet wheels 25 and 35 roject and the correspondingangular relation of pawls 27 and 36 (see Fig. 2). Accordingly while the outer end of the boom under the circumstances just outlined cannot rise, it is free to sink with the bucket even though not as yet unlocked.

The operation of the several parts that enter into the construction of my improved excavating mechanism has been necessarily set forth in connection with the description of such parts. The general operation of the mechanism will now be briefly set forth. Assuming, as a starting point, that the bucket is resting, open, upon the material to be excavated, as shown in the lower right-hand corner of Fig. 1, the crowding boom, it will be observed, sinks to its lowest position under the bucket head until stopped by contact of lug 101 on drum 66 with one of the lugs 100 in locking ratchet 92, causing all of the crowding chain 50 to be unwrapped from drum 67 and all of the closing line to be wrapped around drum 66. In the present design only one turn of such closing line around the drum in question is contemplated, although space is provided for more. In the assumed position of parts, it will furthermore be noted that the outer end of the crowding boom is prevented from rising due to the locking of its rear end in the guide channels 13 and 14, respectively.

Upon the closing line being drawn up taut, the bucket commences to close and is at the same time forced downward into its work. This is because closing line 5, which is wrapped around and dead-ended on drum 66, tends to rotate this drum, and also the drum 67 integral therewith, thus placing a strain on the crowding chain. lhe latter may indeed be regarded as an extension of such closing line. The unlocking drum 70 and locking ratchet 71 being made integral are driven through the medium of the lugs 72 and 7 3; consequently as drums 66 and 67 rotate in forcing the bucket downward, said drum 70 and ratchet 71 are rotated an equal amount .so that the relation between the unlocking chain and the crowding chain remains the same durin this part of the closing of the bucket. owever, as reviously explained. after drum 63 rotates uring the closing of the bucket, being driven by the several wra s of the closing line 5 that pass around it, t irough the prescribed number of degrees (320 in the case in hand), lugs 7 5 and 76 inter-engage so that the unlocking chain drum 70 is now actuated by the trip shaft and so is advanced ahead of drum 67. After drum 70 has rotated a predetermined number of degrees (20 in the case in hand) ahead of drum '67, the roller 87 co-acting with cam 88 causes the dog 91 to engage with the locking ratchet 92 on the head of the bucket, so that drums 66 and 67 can now no longer rotate and the crowding boom can now be unlocked without causing it to be raised through the free rotation of said drum 67.

The unlocking chain drum 70, however, continues to rotate ahead of said crowding chain drum 67, being still driven by drum 63, until it brings the unlocking chain up taut and thereby releases the inner or rolling end of the crowding boom. It is at this stage that the trip shaft, through the medium of which said drum has been driven by drum 63, is reciprocated by' the action of cam 82 on roller 80 to temporarily release lug 76 from its engagement with lug 75. .At this point the rotation of the unlocking chain drum 70 ceases and the closing of the bucket continues and is completed without reference t9 the self-crowding feature. It should be explained that the action of forcing the-bucket downwardly during a part of the closing operation, then looking the drum .66 and releasing the crowding boom, de-

pends entirely upon the closing of the bucket; that is, the action is completed at such time during the closing ofthe bucket as may be predetermined by the design. It might seem that if the drums 66 and 67 rotate to force the bucket downwardly, the releasing of the crowding boom could be delayed until after the bucket has been closed and is ready to ascend; however, the rope which passes around drum 63 and causes its rotation comes from two sources, i. e., from the shortening of the loops 58 and from the unwinding of rope from drum 66. That part of the rotation of drum 63 which is caused by the shortening of the loops, or in other words by the closing of the bucket trays, causes relative rotation between said drum and the other drums, allowing the lug 7 5 to pass through the number of degrees of travel allowed it by the design, and final-1y to overtake the lug 76 on the trip shaft, thus releasing the crowding boom; but that part of the rotation of drum 63, which is caused by the unwinding of rope from drum 66, that is, by the crowding of the bucket, does not cause any relative rotation of said drum 63 with reference to the other drums. This is due to the fact that the rope from said drum 66 is crossed under drum 63 by means of the idler sheaves 62 and 65 so that it passes around said drum 63 in a direction reversed from its direction around .drum 66. llence the rope leaving such last-named drum causes the first drum to rotate in the same direction and, the two being of the same diameter, to rotate the same amount. l*urthermore, since drum 66 is driving drum drum 70, the whole system of drums rotates together and no relative motion occurs during this stage of operation between drum 63 and the other drums.

The bucket having been entirely closedand the crowding boom being released, the bucket is lifted by the closing line in the usual manner. plained how by lockingratchet 71 it is rendered possible not only to lift the filled bucket from its work, but to swing it over the side of an obstruction such as the side of a bin or car, and then partly lower the same again before being opened.

The opening of the'bucket is effected in the usual manner. The holding line 6 being of course held taut, the locking ratchet 71 is held by dog 95 andthe outer end of the crowding boom cannot run down and become locked, so that upon releasing tension on closing line 5, rope will be payed out into the loops 58 to the sides of the bucket hinge and the bucket allowed to open and discharge its load. \Vhen opening is completed, lug 7 5 will have-assumed a certain position back of lug 76; that is, drums 63 and 66 will have the same position relatively to each other that they had at the beginning It has already been exof the previous digging operation, but the unlocking chain drum 70 and the locking ratchet 71 carried thereby will still be in advanced position. However, when the bucket is lowered, the holding line 6 slacks off as soon as the bucket rests upon the material to be excavated, so that both lines are now slack and the links 96 and 97 on the bucket head raise the dog from said ratchet, the unlocking chain drum 70 ro-. tates backwardly and the outer end of the crowding boom descends until the weight of the boom is once more carried on the crowding chain and the rear end of said boom is thereby locked in the guide channels 13 and 14.

As the end of the crowding boom descends and drum 70 rotates backwardly the trip shaft 77, still in unlocked position, rotates under lug 75 until lug 102, secured to said trip shaft, strikes lug 103 on the hub of the crowding chain drum 67. This causes the trip shaft to rotate backwardly into its original position whereupon the clutch jaws 83 reengage.

One cycle of operations has now been completed and the bucket is ready-for another oad. In further explanation of the operation of the crowding boom, it will sufiice to note that when the weight of said boom is carried on the crowding chain, the unlocking chain is slack and the springs 28 and 38 are accordingly left free to force the corresponding dogs against their ratchets. Thus the rolling end-of the upper or coinpression member 10 of the boom is restrained from moving in a direction away from the bucket and the rolling end of the lower or tension member 11 of said boom .is restrained from moving toward the bucket. In this condition of parts the outer end of the crowding boom cannot use so long as its weight is carried by the crowding chain. but it can fall as the bucket sinks into the material under the circumstances hereinbefore described. However, when the unlocking chain comes up taut, the sheaves or drums 49 and 48 rotate, the aforesaid springs 28 and-38 are compressed, and the corresponding dogs released from the ratchets so that the rear ends of both members of the crowding boom are free to travel along the guide channels and the outer end of said boom is free to rise with the bucket.

In conclusion, it may be noted that While the several figures of the drawings are not necessarily drawn to a working scale, the proportions are substantially correct for a bucket having a capacity of 1 cubic yards. Such a bucket will ordinarily weigh about 5.000 lbs. and would be operated by a inch line having a safe working load of 10,000 lbs. \Vith drums of the relative diameters 'shown in the operating mechanism of the bucket proper. the tension on the closing line is calculated to produce an approximately equal tension in the crowding chain, taking into account the bending friction in the rope and the friction of the various sheaves and drums on their pins. Accordingly, when the trays of the buckets meet with a sufiicient resistance, the entire tension on the closing line may operate to force the bucket downwardly so that in the present illustration insteadof having only the dead weight of the bucket (5,000 lbs. for example) minus the tension in the closing line as a force acting to crowd the bucket into the material being excavated, it is possible'by means of my improved construction lit) and design to obtain a downward force of approximately 15,000 lbs.

Other modes of applying the principle of my invention may be employed instead of the one explained, change being made as regards the mechanism herein disclosed, pro vided the means stated by any of the follow iug claims or the equivalent of such stated means be employed.

I therefore particularly point out and distinctly claim as my invention 1. The combination with an excavating bucket and means respectively adapted to raise and lower and to close the same; of means adapted positively to crowd said bucket to its work, substantially as described.

The combination with an excavating bucket and means respectively adapted to raise and lower and to close the same; of means adapted to crowd said bucket to its work. said crowding means including a suitable support. a boom adapted to be locked to said support in desired angular relation. and connections between said boom and bucket adapted positively to move the latter relatively to the former.

3. The combination with an excavating bucket and means respectively adapted to raise'and lower and to close the same; of means adapted to crowd said bucket to its work, said crowding means including a suitable support, a boom adapted to be locked to said support in desired angular relation, and connections between said boom and bucket adapted positively to move the latter relatively to the former, said connections being also adapted to control such locking of said boom.

4. The combination with an excavating bucket and means respectively adapted to raiseand lower and to close the same; of means adapted to crowd said bucket to its work, said crowding means including a suitable support, a boom comprising an upper compression member and a lower tension member pivotally connected together adjacent their outer ends and having their inncr ends movably guided in said support. means adapted to lock such inner ends of said boom members to said support, and connections between said boom and bucket adapted positively to movethe latter relatively to the former.

5. The combination with an excavating bucket and means respectively adaptedto raise and lower and to close the same: of means adapted to crowd said bucket to its work, said crowding means including a suitable support; a boom comprising an upper compression member and a lower tension member pivotally connected together adjacent their outer ends and having their inner ends movably guided in said support. means adapted to lock such inner ends of said boom members to said support, and connections between said boom and bucket. adapted positively to move the latter relatively to the former, said connections being also adapted to control operation of said locking means.

6. The combination with anexcavating bucket and means respectively adapted to raise and lower and to close the same; of means adapted to crowd said bucket to its work, said crowding means including asuitable support, a boom comprising an upper compression member and a lower tension member pivotally connected together adjacent their outer ends and having theirinn'er ends movably guided in said support, means adapted to lock such inner end of said compression member against rearward movement and such inner end of said tension member against forward movement while leaving each such end free to move in the opposite direction, and connections between said boom and bucket.

' 7. The combination with an excavating bucket and means respectively adapted to raise and lower and to close the same; of means adapted to crowd said bucket to its work, said crowding means including a suit its able support, a boom comprising an upper compression member and a lower tension member pivotally connected together adjacent their outer ends and having their innerends movably guided in said support, means normally tending to lock suchinner end of said compression member against rearward movement and such inner end of said tension member against forward movement while leavin each such end free to move in the opposite direction, and connections between said boom and bucket, said connections being adapted to render said locking means inoperative under certain conditions.

8. The combination with an excavating bucket and means respectively adapted to raise and lower and to close the same; of means adapted to crowd said bucket to its work, said crowding means including vertically spaced approximately horizontal guideways forming a support, a boom comprising an upper compression member and a lower tension member pivotally connected together at their outer ends and movably held at their inner ends in said guide-ways, respectively, means adapted to lock such inner ends of said boom members to said guide-ways, and connections between said boom and bucket adapted positively to move the latter relatively to the former.

9. The combination with an excavating bucket and means respectively adapted to raise and lower and to close the same; of means adapted to crowd said bucket to its work, said crowding means including vertically spaced approximately horizontal guideways forming a support, a boom comprising an upper compression member and a lower tension member pivotally connected together at their outer ends and movably held at their inner ends in said guide-ways, respectively, 'acks'adjacent said guide-ways, pinions mounted on the inner ends of said members and meshing with said racks, respectively, spriug-zu'tuated pawl-and-ratchet means normally locking said pinions against rotation, whereby the inner end of Said upper member is held against rearward movement and the inner end of said lower member is held against forward movement, and connections between said boom and bucket, said connections being adapted to render said pawl-and-ratchet means inoperative under certain conditions.

10. The combination with an excavating bucket and means respectively adapted to raise and lower and to close the same; of means adapted to crowd said bucket to its work, said crowding means including vertically spaced approximately horizontal guideways forming a support, a boom comprising an upper compression member and a lower tension member pivotally connected together at their outer ends and movably held at their inner ends in said guide-ways,

respectively, racks adjacent said guide-ways.

pinions mounted on the inner ends of said members and meshing with said racks, respectively, sprang-actuated pawl-andratc'het means normally locking said pinions against rotation, whereby the inner end of said upper member is held against rearward mdvement and the inner end of said lower member is held against forward movement,a winding sheeve in the outerend of said boom, acable attached thereto and connected with said pawl-and-ratchet means to render; same inoperative when said cable is wound in, a cable directly connecting the outer end of said boom with said bucket for drawing the latter towards the former, and another cable connecting said sheave with said bucket for thus winding in said first cable.

11. The combination with an excavating bucket and means respectively adapted to raise and lower and to close the same; of means adapted to crowd said bucket to its work, said crowding means including vertically spaced approximately horizontal guideways forming a support, a boom comprising an upper compression member and a lower tension member pivotally connected together at their outer ends and movably held at their inner endsin said guide-ways; respectively, racks adjacent said guide-ways, pinions mounted on the inner ends of said members and meshing with said racks, respectively, spring-actuated pawl-and-ratchet means normally locking said pinions against rotation, whereby the inner end of said upper member is held against rearward movement and the inner end of said lower member is held against forward movement, a winding sheave in the outer end of said boom, an equalizing sheave, a cable connecting said equalizing sheave with said winding sheave, another cable passing around said equalizing sheave and connectedat its respective ends with said pawl-'and-ratchet means and adapted when placed under tension to render the latter inoperative, a cable directly connecting the outer end of said boom with said bucket for drawing the latter towards the former, and another cable connecting said winding sheave with said bucket for winding in said first cable.

12. The combination with an excavating bucket and a holding line and closing line therefor; of means adapted positively to crowd said bucket to its work, operation of said means being'controlled through said lines.

13. The combination with tin-excavating bucket comprising a head and hinged trays linked thereto, a holding line directly connected with said head for holding and lowering said bucket, and another line for closin said trays; of means adapted to crowd said bucket to its work, said crowding means including a suitable support, and a boom adapted to be locked to said support in desired angular relation; awinding drum in said bucket-head ada ted to be operated by said closing line; an a cable connecting said drum with said boom, whereb said bucket-head may be positively move relatively to the latter.

14. The combination with an excavating bucket comprising a head and hinged trays linked thereto, a holding line directly connected with said head for holding and lowering said bucket, and another line for closing said trays; of means adapted to crowd said bucket to its work, said crowding means including a suitable support, a boom adapted to be locked to said support in desired angular relation, and means for unlocking said boom; two winding drums in said buckethead adapted to be operated by said closing line; a cable connecting one of said drums with said boom, whereby said bucket may be pulled towards the latter; and a second cable connecting the other of said drums with said boom-unlockin means.

15. The com ination with an excavating bucket comprising a head and hinged trays linked thereto, a holding line directly connected with said head for holding and lowering said bucket, and another line for closing said trays; of means adapted to crowd which said closing cable is said last-mentioned drums with said said bucketto its work, said crowding means including a suitable support, aboom adapted-to be locked to said support in desired angular relation, and means for unlocking said boom; a drum in said bucket-head about passed; two winding drums in said bucket-head adapted to be operated by said closing cable; a cable connecting one of said last-mentioned drums with said boom, whereby said bucket may be pulled towards the latter; a second cable connecting the other of said drums with said boom-unlocking means; and means adapted operatively to inter-connect drum.

16. The combination with an excavating bucket comprising a head and hinged trays linked thereto, a holding line directly con nectcd with said head for holding and lower'mg said bucket, and another line for closing said trays; of means adapted to crowd said bucket to its work, said crowding means including-a suitable support, a boom adapted to be locked to said support in desired angular relation, and means for unlocking said boom; a drum in said bucket-head about which said closing cable is p; two winding drums in said bucket-head adapted to be operated by said closing cable; a cable connecting one of said last-mentioned drums with said boom, whereby said bucket may be pulled towards the latter; a second cable connecting the other of said drums with said boom-unlocking means; and automatic means adapted operatively to inter-connect said last-mentioned drums with said first drum.

The combination with an excavating bucket comprising. a head and hinged trays linked thereto, a holding line directly connected with said head for holding and lowering said bucket, and another line for closing said trays; of means adapted to crowd said bucket to its work, said crowding means including a suitable support, a boom adapted to be locked to said support in desired angular relation, and means for unlocking said boom; two co-axial drums and intermediate idler sheavesin said bucket-head about which said closing cable is passed; two winding drums located between said first-named drums; a cable connecting one of said lastnientioned drums with said boom, whereby said bucket may be pulled towards the latter; a second cable connecting the other of said drums with said boom-unlocking means; and means adapted operatively to inter-connect said last-mentioned drum with one or the other of said first-mentioned drums.

18. The combination with an excavating bucket comprising a head and hinged trays linked thereto, a holding line directly connected with said head for holding and low? ering said bucket, and another line for closing said. trays; of means adapted tocrowd said bucket to its work,said crowding means including a suitable support, a boom adapt ed to be locked to said support in desired angular relation, and means for unlocking said boom; two co-axial drums and intermediate idler sheaves in said bucket-head about which said closing cable is passed; two winding drums located between said firstnamed drums; a cable connecting one of said last-mentioned drums with said boom, whereby said bucket may be pulled towards the latter; a second cable connecting the other of said drums with said boom-unlocking means; and means adapted operatively to inter-connect said last-mentioned drum with one or the other of said first-mentioned drums, the operation of said means being automatically controlled by the relative positions of said drums.

Signed by me, this 3rd day of April, 1928.

JAMES C. REID, JR.

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