US1905191A - Excavator - Google Patents

Description

April '25, 1933. F. o. SNOW, JR

EXCAVATOH Filed June 25, 1931 7 Sheets-Sheet l main oo0@m@ 000 April 25, 1933.

F. o SNOW, JR

EXCAVATOR Filed June 25, 1951 7 Sheets-Sheet 2 IIIII'IIIIIIIIIIII I av 12 21/ Foederz'cFn 0. 8 no 20, J2 6y 6% Mr Ap F. o. SNOW, JR

EXCAVATOR Filed June 25, 1951 7 Streets-Sheet 3 dlZZi 5 April 25, 1933. o SNOW, JR 1,905,191

EXCAVAT OR Filed June 25, 1931 7 Sheets-Sheet 5 Inbe 27/50? Eedez aiek 0.832010, J72,

6% 5,15% i gg April 25, 1933. F. o. SNOW, JR

EXCAVATOR Filed June 25, 1931' 7 Sheets-Sheet 6 lumen/770: fi'edezazlok 0. Snow, Jae,

22 24 awr- Patented Apr. 25, 1933 .Y STATES P ATEgNT' om n seamen 0. wow, an, "OF WINCHESTER, ivmssacnnsnms, AssIG onino' MEAD- MORRISON MANUFACTURING COMPANY, or 'EAS'I. Bos'roN, =1vr-AssacnUsms,.n;e0R-

PORATION OF MAINE Application filed June 25,

This invention relates to power excava- (tors, and is concerned with a novel latchtripping mechanism forthe door ofthe excavating scoop. The invention will best be 5 understood by reference to the following tion of the mechanism which moves the scoop in and out, and controls such movements of the scoop;

Fig. 5 is a sectional view on line 55;of Fig. '4;

Fig. 5A is a plan of a portion of the mechanism shown in Fig. 5;

Fig. 5B is an elevation of the parts shown in Fig. 5A, as viewed from theright-hand sidethereot Fig, 6 is a sectional view 011 line 6.6 of Fig. 5;

'Fig. :7 Fig. '5;

a 8' is a plan of a portion of the latchis a sectional view online 7-7 of controlling mechanism;

Fig. 9 is a side elevation of a portion of the 'latch-controlllng mechanism;

- Fig. :10 is an elevation of the-parts shown in Fig. 9, as Viewed fromthe. left-hand side of:Fi 9;

Fig. 11 is a sectional View; on line :ll ll of Fig.8; and

Fig-12 is a ,sectionalview on line 1212 ,of-Fig. '9. I

Referring to the drawings, and to the embodiment of the invention which is illustrated therein, there isshown a scoop which may take various forms, the one herein shown by way of example being a dipper 20,

' rigidly affixed to a dipper stick 21, some- EXCAVATOR 1931. Serial No. 546,783.

times called a dipper handle, which is mounted to;sl ide lengthwise in a gnijde 22, its outward .movement being limited by stop 23 afiixed tothe ,dipperstiek, its inward movement loya' stop 24 'afiigzed to-. the dipper stick. The guide 2 2.is ;pive,ted at 25ron a.boom.26, thelatter being pivoted vat27 on a swingbody 28, which is monnted the dipper stick,-:and then .forwardly abont a sheave wheel; 39, which is coaxial withlf the 'Wardly partway about za sheave wheel .40,

and thence rearwardly andlupwardly abont the drum 36,4to which,.as;previously stated, thefirst .endof theeable is secured. 'Y'Thus, it is evident that when :the 36LisQrotated clockwise, as viewed .in lFig. .1, the

crowd cable 34 is wound-inand, the lresiiltant .pull on the sheave Wheeli39.nngesthefdipper 1 stick 21 outwardly to G130Wd the 20 .into 'the material to be excavated. i l i ep ck, c b ase'i-s antenata on'the boom 26, and}leadsttherefromgfirst forwardly" to and part way about afsheave .Wheel 42 at the-outer endwof stick, thence inwardly sandgrear vvardlyyto; 9

and over a sheave wheell43 ceaxial With-the sheave i v 9, t n e dQWWaI lY ad rearwardly under; a sheave wheel coazi ial with the sheave wheel .40, andthence lypwardly and rearwardly ,to the .npper .side 9 of the drum336, to which gas before stated the I first end of the pnll-backzcab le is seeured.

Thus, 1 it is i evident that 5.36 is rotated contraelockwise, the pul ack cable 35 is wound; in and the'pull wh ch vis;

pivot 25, thence .rearwardly .and downbetween the journal bearing 47 and a collar 52, suitably secured to the "adjacent. end. of the shaft 45. a V

The'drum-36 is loosely mounted on the v xshaft 45, but may be driven'by the latter through an appropriate clutch, herein comprising two clutch members 53 and 54, one secured to the'shaft, as by a key 55, and the other in the present instance being conveniently formed on the drum :36. Herein,

-power;is applied tothe shaft through a gear '56, conveniently formed on the clutch mem- 57 5f appropriate material.

ber '53. The latter'is provided with a facing Engagement and disengagement; of. the clutch is effected by sliding the drumand the clutch 'member carried thereby axially 0n the shaft. The clutch'is normally disengaged by a spring 58 one end of which bears against a hub 59 presented by the clutchmem'ber 53, and the other end against 'a yokeor collar 60, which in. turn operates 1 through a ball-thrust bearing 61 against a "hubp 62 presented by the drum36. Move mm-.- of the yoke or collar under the influence of the spring is limited by suitable means, herein stops comprising nuts 63 threaded ontostubs 64.wh'ich extend loosely through the clutch'member 53, and are fix- .edly secured to'theyoke or collar 60, as by being screwed intog-the' latter,

of the clutch member 53 toward the adjacent bearing 46 is prevented by ashoulder Movement 65, presented by the'shaft 45. a v l Engagement of theclutch in opposition to {the spring 58 iseffected by 'suitable mechan "ism, such as that disclosed in Letters; Patent No. 1,247,564, issued to Almon 'E. Norris November 29, 1917, said mechanism comprisfi ing-acollar 66 mounted on the shaft .45 presenting an abutment 67. fora ball-thrust bearing 68, which is interposedbetween' said drum 36. "Between said hub and said abutabutment and a' hub, 69 presented. bythe ments, there is a body later to be described, --by' which the thrust of the collar 66 through the thrust bearing-68 is communicated to the drum '36 'to slide the latter axially against the yielding opposition presented by'Fthe spring 58, thereby to effect engage-.

- ment oif the clutch members 53 and 54.

yoke" 70, encircling the collar '66 and pivoted at171 thereto', -;carries 'a' pair ofadjusting screws 72, presenting abutments '73 for endwise engagement with pins 74 carried by screws 75 threaded into nuts 76 fixedly secured in the frame member 49. Simultaneous rotation of these screws in the proper direction causes an endwise thrust to be exertedagainst the abutments 73 carried by the yoke 70, thereby moving said-yoke and the thrust collar 66 toward the drum 36. V The clutch engaging screws 7 5 are formed on rockshafts 77, which, as shown in Fig. 4,

are suitably connected to each other for simultaneous operation by bell-crank levers 78 and-79 secured to said shafts, and having arms 80 and 81 connected to each a link or links 82.

Still referringto Fig. 4, a hand lever 83, fulcrumed on a pivot 84, is suitably conother by nected to the bell-crank lever 78 as by a link 85, an arm 86, a rockshaft8 an arm"-' V 88 and a link 89. This hand leveris shown in its neutral position'in Fig. 4. Movement of the handle toward the left in Fig. 4,-

that is to say, toward the operator who stands facing the lever from that side, oper ates through the described mechanism to engage the clutch. When the lever. is moved back to its neutral position, the clutch releasing spring causes disengagement of the i clutch.

Referring again to Fig. 5, the shaft 45' is rotated by power in the direction of the arrow thereon,that is to say, clockwise asyviewed in Fig. 4. Accordingly, when the described clutch is engaged, the drum 36 is rotated clockwise by the power of the engine or motor. There is associated with the drum an automatic brake now to be described, which permits free rotation of the drumby power clockwise, but normallyprevents rotation contraclockwise. Referring now-to Fig. 7, this brake comprises a brake-drum 90' herein conveniently formed as an integral part of the drum 36, which brake-drum-cooperates with a brake member exemplified bya brake-band 91 provided with two relatively movable terminals 92and 93. These terminals are differentially connected to a hanger, herein a link 94, which is pivoted at 95 to a suitable fixedsupport, such as a bracket 96, mounted on the base of' the machine. The terminal 92 is connected by one or more, herein a pair of'links 97 and a pivot 98 to the link 94. Theterminal 93.

is connected to the link in a manner which"'" 12o will appear. presently. a

A suitably arranged spring 99 urges the link 94 toward the right (Fig. 7 ),that is to say, clockwise about its pivot-95, 'butin a generally countraclockwise direction con-' sidered with reference to the brake-drum. Movementof the link in such direction is "limited by an appropriate stop 100, herein conveniently formed as an integral part of;

the bracket 96. The spring ShOWIl -IS' helically coiled about 'a rod 101 which extends freely through an opening 102 provided "in curved surface 103 on the "link 94, said surfaee permitting limited rocking movement of the link with relation to the rod. The

other end of the spring rests against an abutment,'herein a'washer 104 and a nut 105, the

latter beingthreadedonto the rodf101.

The relative arrangement of the brake parts thus far described is such that when the-brake drum is rotated clockwise'asviewed in Fig. 7, the spring '99 .yields and allows the link 94 to'swing towardtheleft,'the differential action of the brake-band thereby permitting the'latter to relax. I WVhen, however, there is any tendency of the brake- .dru'm'to rotate contra-clockwise, such "tendency is resistedby automatic application of the brake. The brake may be r'elea'sedat will,'l1owever, by moving the terminal 93 clockwise, considered with reference to the brake-drum. This is conveniently accomplished'by connecting the terminal 93 to the link 94 by a rocking lever 106, having two short arms 107, which are side byside, and embrace said terminal, The link 94: is bifurcated to embrace the "rocking lever 106, as well as links 97 (see the upper righthand portion of Fig. 5).

WV-henthelever 106is rotated contra'clockwise about" its fulcrum (Fig 7) its arms 107 swing toward the left, and 'thebrake-band is 'relai'ed, thereby freeing the brake- drum 90 and 1 allowing it to rotate contraclockwise. It'shouldhere be understood that'this release of the brake is effected without disturbing thespring 99 and link 9\4','th'at is to say, it is accomplished irrespective of the action of the automatic brake applying means. I

The brake re'leasing lever is manually controlled by mechanism new to be described, reference still being had at'fir'stito '7. r The lever 106 is providedjwith a second arm 108, "which is connected by a link'f109 to l'an arm 110, the latter (see Fig. 5A) being connected by a'link'111'to an arm 112 secured to la roc'kshaft 118, to the other endof which there is'secured an arm 114, which is connected by a pair of links 115'to an arm'116'secu'1edto a rockshaft'117. vReferring again to Fig. 7, thelink -109'is arranged generally parallel with a straight line containin'g 'the centers of the pivots of the link 94:,and the lever "106, and vhence does not interfere With the releasing action f movement of thero'ckshaft 117 isyieldin'gly resisted by a spring '118,which is connected to the 'rockshaft by an arm "1190f a bellis mounted to slide.

13ml position; bell-crank lever 79 is turned clockwise by the useof the hand lever 88, it tends to crank lever "120 secured to the rockshaft,

said arm being connected by a pivot 121'to rod 122, which carries 'an abutment 123 against which oneiend of the spring rests, while theother: end of the spring is seated against an abutment 124, in which the rod The abutment 124'is provided with a pivot 125, whieh turns in the adjacent frame member 49. "When,

therefore, the rockshaft 117 is rocked about its axis and the frame 119 swings to and fro, the rod 122 slides forward and back ward in the guide 124,'and the latter rocks on its pivotal-mounting.

Release of the brake'in opposition to the to be described, 'refe'rence being had to Fig. 4. The bell-cranklever 120 is provided with a second arm 126, connected by a pivot 12? to a sleeve 128, the latter'being mounted to slide lengthwise on arod 129, which is in-thena- 'ture'of alink connecting said arm to anarm 130 011the bell-crank lever 7 9, which it will be remembered is'one ofthelevers for operating'the clutch-engaging screws.

Two centering springs 131 and 132 encircling the rod 129, and interposed between the sleeve 128 and abutments 133 and 134 *car'ried'by therod,'tendto restore the hand lever and the connected parts to their neu- WVhen the arm 130 of the place the spring 132 under compression, and in so doing effects release ofthe automatic brake, inasmuchas it acts through-the sleeve 1 128, "arm 126, rockshaft 117, arm 116 (see' 'Figu5iA), links115, arm 114, rockshaft 113,

a'rm112, link111,arm 110, link 109 (see Fig.

'7) and arm 108,-to swing thebrake-releasing arms 107'of the lever 106 contraclockwise to release the automatic brake. "Since the releasingmovement of the brake. is through the interposition of the spring 132 (See'FigQ '4) the'release and reapplicfation of the brake can be contrelled to arnicety, and it canbe "applied and released 'gradually'and sensitively. V r The described connections between the hand lever and the automatic brake are such that movement'of the ihand lever from the neutral position shownin Fig. 4 toward the right (forward from the operator.) release the automatic brake. Inthis, connection, it

will'b'e rememberedthatmovement of the .jhand lever to the left (backward toward .a "the operator)'engagesthe clutch. Thus it is apparent that when'the operator moves I the hand lever backward (toward him), power is applied to rotate the drum 36 clockwise,'a's viewedin Fig. 4. When the,

hand leveris restored 'to its neutral position, the clutch is disengaged, and reverse rotation of the drum ,is prevented by the automatic application of the brake. When, however, the operator moves the hand lever .forward (from him), the automaticbrake is released, and the drum is free to rotate contraclockwise.

. i I will now describe the'mech'anism for urging the drum in the direction opposite to that of the shaft, andat high speed, reference being had to Fig. 5.. In the example shown, this mechanism is in the form of a planetary gearxset, and comprises an internal gear 135, secured as by a spline 136,

to the shaft 45, a sun gear. 137 (externally -toothed) secured' as by pins 138 to the drum '36, and one or more, herein three planet pinions 139, meshing with the gears 135 and 137, andmounted to rotate on studs 140 secured to a planet pinion carrier 141,'which is loosely mounted on the hubd69 of the drum 36. 1

The planet pinion carrier presents a brake-drum 14 2, cooperating with a brake member, herein *a band 143,'about the brakedrum. Referring now to Fig. 6, this band has two terminals 144 and 145, one of which 7 is anchored by a pin 146 to a bracket 147, "While the other is connected by a pivotal pin .148 to an arm 149 secured as by a key 150 to a rockshaft v151, which is coaxial with and coupled to the rockshaft 117 by a 7 coupling 152..

. When the rockshat't 151 is rotatedcontraclockwise as viewed in Fig. 6, the band is contracted about the drum, and theplanet pinion carrier. is held against rotation, thus causingthe planet pinions to rotateabout a ffiXed axis, and to rotate the sun gear 137 and the drum 36 contraclockwise athigh speed,

Y The seating of the brake-applying arm 149 on the rockshaft 151 is such that anextreme forward niovement of thehand lever 83 (toward theright in Fig. 4) causes this high e speed reverse rotation of the drum 36.- Thus "when the lever is; moved fromfits neutral position forward (toward the rightin Fig.

4), the automatic brake. is firstreleased, and

7 "*further movement of the hand ilever'in the gearing intooperation. r

1 It will be remembered that when the drum same direction brings the high speed reverse '36 is rotated clockwise, it is coupled directly to the drivingshaft by the clutch. It follows that the crowding cable, which is urgthedippcr into the material, is being 'woundinat the speedof the drivingshaft.

V It will also-be remembered that when the.

planetary gea rsetis in operation, thedrum is rotated contraclockwise and at high speed. Ittherefore follows that the pull-back, Cable ,is wound ina't acorrespondingly high speed,

; and that backward or idle. movement of the shovel consequently is speeded up. The con- .trol" of. the forward 7 and backward move-f door.

place inflthe opening 157.

.ments of the dipper stick is vested in the.

hand lever 83, which therefore controls'the in and out movements of the dipper. It is important to remember this, because, aswill presently appearjthis same hand, lever car-.

'ries the device which controls the; tripping ofthedoor latch of the dipper, and hence the operatorcan trip the door latch at any instantlby the same hand which controls the in and out movements of the dipper, and

"without relinquishing his grasp upon the" hand lever. I

The dipper, with its door and latch, and the latch-tripping mechanism will now be described, reference being bad at'first to,s0

Figs. 2' and 3. As isusual, one end of the dipper,that"-is to say, the digging end, is open, and the other endv is provided'with a door 153, which is pivoted at 154 at thetop of the dipper. This door is normally locked 8 V in its closed position by a suitable latch I 155, which, as shown,is slidably mounted in a guide 156, the latter beinglsecured to the V The lower end of the latch is normally received in an opening157 in a plate.v 158 secured to the under side of the dipper. The latch is normally held in door-locking position, andis restored to such position by a suitably arranged'spring 159, one end of 'which abuts against thefupper end of the latch, and the other against an abutment 160 secured to. the door. A rod 161, secured to the upper end of the latch,.extends through the spring, andthrough the abutment 160,

The latch may be li ftedinopposition to the spring by a latch-lifting lever 164, pivoted at 165 on the guide 156, and presenting,

abutments 166 engagingthe under side of anoverhanging abutment 167, presented by the, latch. Downwardswinging movement of the lever (and consequently downward sliding movement of thez latch) is limited. 1

by an adjustable stop screw 168 threaded V .into'the'lever', and engaging at is lower end an abutment 169 on the outer face of'the (1001* 153. a r p I The latch lever is lifted or tripped by av latch-tripping rope 17 0, suitably attached" to the lever, as by ajclevis 171, secured by a pm .172 to {a lug 173 presented by the lever.

This rope leads upwardly, and, as shown in Fig. 1, over a sheave wheel 174 carried. 12 by the outer end of th'e; dipper stick,'-thence rearwardly between two sheave wheels 175 carried by the boom, thence .over two sheave wheels 176 and 177 at the'upper portion of the swing body, thence f dowllwardly'over a vertically movable. sheavewheel 17.8, and

finally upwardly to the point 17-9, where it is dead-ended. Referring now to. Fig. 4, it will be seen that the Vertically movable movable traveler; 180,. whose. weight, to: gether with that of the sheave wheel. and

other associated. partscarried by the travel-i er, normally maintains-the rope or cable in a condition in which it will not trip thelatch,...that is to say, as. the dipper stick moves inwardly, the weight of these parts takes up. the slack, as the. loop is. enlarged by the descent ofv the take-up device, and on the other hand, when the dipper, stick ismoved outwardly, the take-up device rises.

By holding the take-up device fixed at any point in its vertical movement, outward movement of the dipper stick may be utilized to cause the latch-tripping rope to exert a pull on the latch, and to trip the latter To. this end, the traveler 180. carries anappropriate clamp (see Fig. 12),.comprising two clamping members18l and 182, disposed. on opposite sides, respectively, of a fixed vertical rod 183, Whose lower end (.seeFig. 1) is. secured to. a: bracket 18a, and. whose. up.-. per end is bent horizontally asv at 185,.andv is secured to a. bracket 186.. Referring again to Fig. 12, the olampingmembers 181 and, 182 are. connected to. each other at one pair of. ends by a pair of links 187,, and their other ends by an. arm 188, the latter being mounted on a vertically disposed rockshaft 189, by means. which, in effect, is a splined connection, two sides. of the shaft being. slabbed ofi'as at190, and the arm 188 being correspondingly shaped to, fit the cross-sectional shape of the shaft. The clamp is normally relaxedby a spring 191, one. end of which bears against a, lug 192: presented by the; clamping member 182, while the other end rests against an abutment, herein. one ofa. pair'of nuts193, threaded onto, a rod 19.4, which extendsloosely through said lug, and; is pivoted at 195 tolthe links 1 87 'The opening: movement of the clamp, under the influence of this spring, is. adjnstably limit-- ed by one of a pair of nuts 196, threaded onto the rod 194, and engaging the-Lug 192.

Clamping action of the clamp in opposition to the spring is cause-dby rocking the shaft 189 about its vertical axis thereby swinging the arm 188 cont-raclockwise, thus to. cause the clamp 181* tov approach the rod 183. The clamp- 182 is provided with a pair of ears 197', disposed, above and below the arm,1 88'an.dk about the rockshaft 189. The clamping member 182' is attached to the traveler as by ears. 198. When, therefore, the: traveler moves up and down,

the clamp moveswith it. The rockshaft 189 is mounted in appropriate upper andlower bearings 199 and 200 .(seeFig; 4).

As already intimated, the control, of thev I latch preferably is vested. inthe. same hand which controls. the hand lever. 83 for conr,

trolling the in and. out movementslof the. dipper stick, To. this end,.thereis 111011111},

ed on. the'lever 83 a latch controlling mem;

ber, herein a small lever 201 mounted, on. a

pivot 2O2'onv the lever 83, adjacent to, the. grasping portion of the latte'r 'and; suitably connected to the described vertically" movable traveler as by a link 203, WhQSQllP-g perend. is pivoted at 204.to.the lever 201, and whosev lower end. is pivoted at 205 to,

one arm 2060f a bell-crank lever 207', whose.-

other arm 208 is connected bya link; 209.110,

an arm. 210,:the latter being secured to the lower: end of. the. vertical rockshaft ),,be} low the base or floor plate 50,. Thepivotalf' connection 205. between thev link. 203 and.

the arm 206 is disposed with itsaxis sub-.

stantially coincident with the axis of the,

pivot 84, on which the lever .83 is: fulcrumed, as a result of which rocking movementfo-f the lever 83 hasno effect upongthe'verticalg ly movable traveler.

squeezing the small lever 201' toward; the large lever 83, cause the traveler to beheldin fixed position, as a consequenceof which,

outward movement of. thedi pper stick undet. the control of the lever. 831wi ll. cause, the.

latch to he tripped. In practice, the 0 a erator by. forward .movement. of. the. level; 88 causes the dipper to bemovedloutwardly toward the pin where the load, is tonbe discharged, and just a few inchesbefore.

the dipper reaches that point, the operator,

presses his thumb or the palm, of the hand adjacent the base of the. thumb against the lever 201, thus squeezing. theqlatter to; Ward the grasping portion, ofthe lever. 83.

A slight further movement ofthe. dipper in an outward direction causes the door 1. In an excavator, the combination ofaf scoop provided. with a 10 7, ilatGhUfQn;

holding said door closed,,. a, latch tripping rope, a. take-up for said rope; aggnide for said take-up, a clampcarrred, by said take up, means for moving .said scoop, means, consequent upon movement of SHJCLSGOOPJQO- cause said rope to tripsaid latch, and-means.- control-led' by the operator 7 tocause said clamp. to clamp said guide, therebytohold said take-up fixed, thereby .to predeterminethe, point in the movement of said scoop,

when said rope will trip said latch.

On the other hand, however, at any point ii -the movement. of] the lever 83, the operator may, by simply:

2. In an excavator, the'combination of a scoop provided with a door, a latch for holding said door closed, a latch-tripping rope,

:Ineans for moving said scoop, a normally operative take-up device which maintains saidropein a' condition in which it will not trip said latch, a guide for said take-up device, a clamp carried by said take-up device, and means at will to cause said clamp to clamp said guide, thereby to render said take-up device inoperative, thereby to cause 7 saidrope to trip said latch when said'scoop ismo ved. I r

3,111 an excavator, the combination of a scoop provided with a door, a latch for holding said door closed, a latch-tripping rope, means for 'movingsaid scoop, a take-up detake-up'd'evice inoperative, thereby to cause said latch to betripped when movement of said scoop subjects said rope to tension.

- 4.- In 'an excavator, the combination of a scoop provided with a door, a latch for holdingfsaid door closed, a latch-tripping rope connected to said latch,;a portion of said rope being arranged in the form ofa loop,

means to move said scoop to and fro, takeup means in said loop automatically respon- V .sive to movements of said scoop to take up slack in said rope by varying the size of said loop, a guide for said take-up means, a clamp carried by said take-up means, and.

means at will to hold said take-up means fixed by causing said clamp to grip said guide;

5.'In an excavator, the combination ofa' scoop provided with a door, a latch for holdmg said doorrclosed, a latch-tripping rope connected to said latch, a portion of said rope being arranged in the form of a loop, means to move said scoop to and fro, gravi-r ty controlled take-up means in said loop automatically responsive to movements of said scoop to take up slack in said rope by varying the size of said loop, a vertical guide for said take-up means, a clamp carried by said take-up means, and means at will to' hold said take-up means fixed by causing said clamp to grip said guide.

6. In an excavator, the combination of a scoop provided with a door, a latch for holding. said door closed, a latch-tripping rope connected to said'latch,-a portion of said ,rope being arranged in the form of a depending loop, means to move said scoop to 7 and fro, gravity-controlled means including abody supported by said loop and varying thesize of the latter as said scoop is moved to and fro, a guide for said body, a clamp carr ed by said body, and means at will to hold said body fixed by causing said clamp to grip said guide."

7. In an excavator, the combination of a scoop provided witha door, a latch for hold,- ing said doorclosed, a latch-tripping rope, a take-up for said rope, a guide for said take-up, a clamp carr ed by said take-up,

said clamp comprislng two clamping mem bers disposed on opposite s des, respectively, of said guide, means for moving said scoop,.means consequent upon movement of said scoop to vcause said rope to trip said latch, and meansco'ntrolled by the operator to move said clamping members toward each other and toward the interposed guide,; thereby to hold said take-up fixed, thereby to predetermine the point inthe movement o'fs'aid scoop whensaid' ropewill tripsaid latchu 8. Inan excavator, the combination of a scoop provided with a door,.a latch for hold ing said. door closed, a latch-tripping rope,

atake-up for said rope, a guide for said take: up, a clamp carried by said take-up, said clamp comprising two clamping members disposed on opposite sides, respectively, of

said guide, a spring normally relaxing said a clamp, means for moving said scoop, means consequent upon movement of said scoop'to cause said rope to tripsaid latch, and means controlled by tlie'opera'tor to move said clamping members toward each other and toward the interposed guide, thereby to hold said take-up fixed, thereby to pre'determine the point in the movement of said scoop when said rope will tripv said" latch.

9. In an excavator, the combination 6f a scoop. provided with a door, a latch for holding said door closed,,a latch-tripping rope, a take-up for said rope, a guide for said take-up, a clampcarried by said take up, said clamp comprising two clamping members disposed on opposite sides, respec-, tively, of said guide, a spring normally re-' laxing said clamp, means adjustably limit ing the relaxing movement of said clamp under the mfiuence of sa d sprlng, means for moving said scoop, means consequent uponmovement of said scoop to cause said rope to trip said latch, and meanscontrolled by the operator to move said clamping members toward each other-and toward thein: terposed guide, thereby to hold said take-up fixed, thereby'to predetermine the point'in the movement of said scoop when said rope-,

will tripthelatch. V I 7 V 10. In an excavator, the combination of a scoop provided with a door, a latch for bold. ing said door closed, a latch-tripping rope,

a take-up 'for said rope, a guide for said take-up, a clamp carried by said take-up,

said clamp comprising two clampingmenr,

bers disposed on opposite sides, respectively,

of said guide, an armcarried by said takeup and connecting said clamplng members to each other, means for moving said scoop, means consequent upon movement of said scoop to cause said rope to trip said latch, and means controlled by the operator to move said clamping members toward each other and toward the interposed guide, thereby to hold said take-up fixed, thereby to predetermine the point in the movement of said scoop when said rope will trip said latch.

11. In an excavator, the combination of a scoop provided with a door, a latch for holding said door closed, a latch-tripping rope, a take-up for said rope, a guide for said take-up, a clamp carried by said take-up, said clamp comprising two clamping mem bers disposed on opposite sides, respectively, of said guide, an arm carried by said take-up and connecting said clamping members to each other, a rock-shaft extending lengthwise of said guide and having a splined connection with said arm, means for moving said scoop, means consequent upon movement of said scoop to cause said rope to trip said latch, and means controlled by the operator to move said clamping members toward each other and toward the interposed guide, thereby to hold said take-up fixed, thereby to predetermine the point in the movement of said scoop when said rope will trip said latch.

12. In an excavator, the combination of a scoop provided with a door, a latch for holding said door closed, a latch-tripping rope, a take-up for said rope, a guide for said take-up, a clamp carried by said take-up, said clamp comprising two clamping members disposed on opposite sides, respectively, of said guide, a rock-shaft extending lengthwise of said guide, a rocker-arm carried by said take-up and slidable lengthwise of and on said rock-shaft, said rocker-arm having non-rotatable connection with said rockshaft and connected to said clamping members to urge them toward said guide, means for moving said. scoop, means consequent upon movement of said scoop to cause said rope to trip said latch, and means controlled by the operator to move said clamping members toward each other and toward the interposed guide, thereby to hold said take-up fixed, thereby to predetermine the point in the movement of said scoop when said rope will trip said latch.

13. In an excavator, the combination of a scoop provided with a door, a latch for holding said door closed, a latch-tripping rope, a take-up for said rope, a guide for said take-up, a clamp carried by said take-up, said clamp comprising two clamping members disposed on opposite sides, respectively, of said guide, a link connecting said clamping members together at one pair of ends, an arm connecting said clamping members together at their other pair of ends, means to rock said arm toficause. said clamping members, to; move one toward the other, means tor moving said: scoop, means consequent upon movement of; said scoop to cause said nope totripsaiddatch, and means controlled by the operator to move said clamping members toward each otherand; toward: the in: terposect guide, thereby to hold said; take-up fixed-,thereby, to; predetermine the-point in the movement of said; scoopv when said-rope willttripisaid l'atch. a i

14%. In an: excavator, the: combination ofa scoop provided, with a door, a latch for hold ing said door closed, a-latch-trippingrope, a; take upgfor saidrope, a guide for said take-up, a clamp carried by said take-up, saijdclamp comprising two clamping-members disposed on opposite sides, respectively, of said(gui de, aIlink; connecting said clamping memberstogether'at one pair of ends, an arm connect-ing. said clamping members to-' gether at their other pair of ends, means to rocksaid arm to cause said clamping members to, move one toward the other, a; spring normally tending to movesaid clamping, members apart, means for moving, said scoop, means consequent upon movement of said scoop; to cause said rope. to trip said latch, and means controlled by the opera,- tor to move said.v clamping members toward each other and: toward the interposed guide, thereby to holdsaid take-up fixed, thereby to predetermine the point in the movement of said scoop when said rope will, trip said; latch, v H

LE5, In an excavator, the combination ot a scoop provided with a door, a latch for holding said door closed, a latch-tripping rope, a takev-up for said rope, aguide for saidtake-up, a clamp carried by said takeup,,saidclamp comprising twoaclamping members disposed on opposite sides, respect-ively, of said guide, a link connecting said clamping members together at one pairof ends, an arm connectingjsaid"clamping members together at their other pair of ends, means to roclgsaid arm to cause said clamping members to move one toward the other, a spring connected to said link and normally tending to move said clamping members apart, means for moving said scoop, means consequent upon movement of said scoop to cause said rope to trip said latch, and means controlled by the operator to move said clamping members toward each other and toward the interposed guide, thereby to hold said take-up fixed, thereby to predetermine the point in the movement vof said scoop when said rope will trip said latch.

16. In-an excavator, the combination of a scoop provided with a door, a latch for holding said door closed, a latch-tripping rope, a take-up for said rope, a guide for said take-up, a clamp carried by said take-up, said clamp comprising two clamping members disposed onopposite sides, respectively, of said guide, a rock-shaft extending lengthwise of said guide and extending through a one of said clamping members, a rocker-arm through which said rock-shaft extends, said rocker-arms connecting said clamping members together at one pair of ends, means connecting said clamping members together at their other pair of ends, means for moving u said scoop, means consequent upon movement of sald scoop to cause said rope to trip saidlatch, and means controlled by the operator to move said clamping members toward each other and toward the interposed guide, thereby to hold said take-up fixed, thereby to predetermine the point in the movement of said scoop when said rope will-trip said latch.

, 17 In an excavator,the combination of a scoop provided with adoor, a latch for hold ing saiddoor closed, a latch-tripping rope, a take-up for said rope, a guide for said 'take-up,-a clamp carried by said take-up,

said clamp comprising two clamping members disposed on'opposite sides, respective.-

ly, ofs'aid guide, a'rock-sha-ft extending lengthwise of said 1 guide and extending through one of said clamping members, a rocker-arm through which said rock-shaft extends, said rocker-arm connecting said clamping members together at one pair of' ends, a link connecting said clamping mem bers together at the other pair of ends, means for moving said scoop, means'consequent upon movement ofsaid scoop to causesaid,

rope to trip saidlatch, and means controlled by the operator to move said clamping mem bers'toward each other and toward the interposed guide, thereby to hold said take-up fixed, thereby to predetermine the point in the movement of said scoop when said rope will .trip said latch.

In testimony whereof, I have signed my name to this specificationr FREDERICK o. sNow, JR.

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