US2674815A

US2674815A - Bowl and apron control for carry type scrapers

Info

Publication number: US2674815A
Application number: US111496A
Authority: US
Inventors: William J Adams
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1949-08-20
Filing date: 1949-08-20
Publication date: 1954-04-13
Anticipated expiration: 1971-04-13

Description

April 13, 1954 w. J. ADAMS 2,674,815

BOWL AND APRON CONTROL FOR CARRY TYPE SCRAPERS Filed Aug. 20, 1949 4 Shets-Sheet l INVENToR. WILL/An c7.' AOA/16 A TTURNEY April 13, 1954 w. J. ADAMS BOWL AND APRON CONTROL FOR CARRY TYPE SCRAPERS n INVENTOR. WML/,4M J.' A0A/1.5

4 Sheets-Sheet 2 47'7'0RNEY6 Filed Aug. 2o, 1949 April 13, 1954 -W. J. ADAMS BOWL AND APRON CONTROL FOR CARRY .'IYFE SCRAPERS 4 Sheets-Sheet 3 Filed Aug. 20, 1949 INVENTOR. WML/4M 'Z' A0A/ms BY @We April 13, 1954 w. J. ADAMS 2,674,815

BOWL AND APRON CONTROL FOR CARRY TYPE SCRAPERS Filed Aug. 20, 1949 4 Sheets-Sheet 4 mrc M ze INVENTOR. WMU/9M c7.' Aga/15 Patented Apr. 13, 1954 BOWL AND APRON 'CONTROL FOR CARRY TYPE SCRAPERS William J. Adams, Santa Cruz, Calif., assignor,

by mesne assignments, to General Motors Corporation, Detroit, Mich., a corporation of Dela- Ware Application August 20, 1949, Serial No. 111,496

4 Claims. 1 This invention relates to improvements in a power scraper adapted to dig up and carry away large quantities of earth or similar material.

One of the objects of the present invention is to provide a scraper of the type described wherein a scraper blade is provided transversely of the bowl forward of the mid portion thereof so that a portion of the load moves into the bowl rearward of the blade and another portion moves into the bowl forwardly of the cutting blade. Combined with this feature, an ejector comprises the bottom and rear wall of the bowl and is pivoted about; a transverse pivot parallel to the cutting blade for tilting of the ejector at a very steep angle for unloading.

Another object of the present invention is to provide a front gate with a very high lift and wherein the front gate and ejector are so constructed and arranged that they nest within each other at their fully raised position so vas to obtain the maximum dumping eiciency.

Still another object of the present invention is to provide an ejector having a rear wall which flares upwardly and toward the rear and extending entirely to the top of the bowl giving a wide open top and a rear wall for full loading. My invention also comprises a box beam, an extension wall above the top of the rear portion of the ejector providing for a greater piling of the load at this point and the box beam protecting the ejector against damage when loading by shovel or other overhead equipment.

A further object of the invention is to provide an ejector gate which is moved to such a `steep angle during dumping that its center of gravity moves over the ejector pivot, at the same time loading a spring which serves to move the ejector gate center of gravity back over its pivot on the return movement, thus permitting the use of a single acting hydraulic jack or hoist for the ejector dumping movement.

Another feature of my invention is the provision of a teleseoping hydraulic jack for use in dumping the ejector arranged in such a Inanner that the dumping action increases in speed as the load upon the ejector decreases.

A further object of my invention is the connection of a pull yoke between a tractor and the scraper bowl and the mounting of the lifting device for the front apron or gate on the pull yoke whereby the lifting movement of the pull yoke is added to the lifting motion of the front apron actuating device to provide a very high lift for the front apron during dumping.

A further object of my invention is the provision of the lifting device for the scraper bowl on the pull yoke so that a great percentage of the scraper load is transferred to the drive wheels of the tractor.

- Still another object of the present invention is to provide novel hydraulic hoist operating means for the bowl and the front gate of the scraper mounted on the pull yoke in a novel manner.

A further feature of the present invention is the provision of a novel plural sheave arrangement connected with Vthe hydraulic hoist mounted on the pull yoke so as to multiply the power of the hydraulic hoist as applied to the lifting of the bowl and the lifting of the front apron.

A further object of the present invention is a novel arrangement of the lifting hoist and the construction of the pull yoke so as to give the tractor operator a good view of the s-craper dumping and loading action.

A further object of the present invention is the provision of powerful hydraulic hoists for power and the application of that power by means of flexible cables to the front portion `of the scraper bowl and to the front apron of the scraper so as to permit lboth the bowl and the apron to float in a desirable manner without cable interference.

A further object of the present invention is to provide a scraper of very strong construction wherein the sides of the scraper bowl, the ejector and the front gate, and the rear frame and pull yoke are of strongly reinforced construction so that the scraper is very sturdy and rugged.

A further object of the present invention is the careful selection of the pivot point between the pull yoke and the scraper bowl, taken in conjunction with the position of the .digging blade, whereby the digging load on the scraper blade is transferred to the drive wheel of the tractor in a novel and emcient manner.

Still another feature of the present invention is the positioning of the hinge connection between the tractor and the scraper in such a fashion that the tractor drive wheel torque load is transferred to the driving wheels of the tractor in a novel manner. Y

A further object of the present invention is the provision of single acting hydraulic lhoists for controlling the three separate motions of the scraper together with a simple control valve for each motion mounted on the tractor which gives a very simple and direct operating system yand one which is very simple when it comes to locating hydraulic trouble.

Other objects and advantages -of the present invention will be apparent from the accompanying drawings and description and the essential features thereof will be set forth in the appended claims. Y

In the drawings,

Fig. 1 is a side elevational view of a scraper equipped with my various inventions and showing a rear portion of the tractor which pulls the same;

Fig. 2 is a fragmental top plan View of the scraper of Fig. 1;

Fig. 3 is a longitudinally extending sectional view taken generally along the line 3-3 of Fig. 2;

Fig. 4 is a diagrammatic view illustrating the hydraulic system for operating the various hydraulic hoists;

Fig. 5 is a fragmental sectional view enlarged taken along the line 5-5 of Fig. 1;

Fig. 6 is a diagrammatic View illustrating the reeving of the cables on the hydraulic hoists mounted on the pull yoke and connections of these cables to the scraper bowl and the scraper front apron; while Figs. '7 and 8 are enlarged diagrammatic views with only pulleys and cables of repectively the bowl hoist and apron hoist construction.

In Figs. l, 2 and 3, I have shown a scraper bowl I comprising two vertically extending parallel side plates Ii rigidly connected together by a box beam construction I2 at the front end, by upper and lower laterally extending box beams I3 and I4 respectively at the rear, and by a triangularly shaped box beam I at the mid portion of the bottom of the side walls just to the rear of the cutting blade I 6 which is rigidly mounted on the box beam i5. rEhe side plates I I are entirely flat and unobstructed on their inner side as shown in Figs. 2 and 3. They are reinforced on their outer surfaces by means of the vertically extending channels Il and I8 and by the horizontally extending channels I9, 20 and 2l. These channels numbered I'l to 2l have the free edges of their flanges welded to the outer face of the plate II so that the webs of the channels are spaced from and parallel to the plates II giving, in effect, box beams at each of these channel connections. Rearwardly of the box beam I5, the bottom of the scraper bowl is provided by the bottom portion 22a of the ejector which is continuously connected by a curved portion with an upwardly and rearwardly flaring back wall portion 22h which is an integral part of the ejector. The ejector is comprised of two parallel plates 23 which are welded to crosswise extending spacers 24 and parallel stiffening ribs 25. The side edges of the ejector which are closely parallel to the inner faces of the scraper bowl side plates II, are closed by plates 26 which are welded to the plates 23. This gives a very strong construction for the ejector. The ejector is pivotally mounted bv the hinge 21 on the top or apex portion of the triangular box beam I5 as clearly shown in Figs. 2 and 3. The box beam I3 may have an extending skirt I3a extending downwardly to substantially meet the upper edge of the eiector portion 221i when the scraper bowl is in its rlll position as shown in Fig. 1. To hold a greater load, an extension wall may be provided vertically above the b box beam I3 and comprising a vertically extending plate 28 which extends across the entire width of the bowl and which is reinforced by a plurality of parallel ribs 29 which are welded to the plate 28 and to the top of the box beam 53.

The rear support for the scraper bowl is very strongly constructed. Two box beams 3! are rigidly connected as by welding to the rear face of the box beam I3 at points inwardly from the side plates I of the bowl. These beams 3e extend rearwardly and downwardly to a bumper 3|'. vertically below each of the beams 30 is a beam 3l. These beams are also welded to the rear face of the box beam I4 and extend generally horizontally, tapering inwardly toward 50 which extends crosswise of the vehicle.

each other to the bumper 3i'. The four

beams

30, 30, 3l and 3l are welded together to the bumper 3l' against which a pusher tractor or bulldozer may exert its pushing effort when aiding the loading of the scraper or moving the scraper forward by additional power. A hook 32 may be provided at this point in case the scraper is used to pull a following vehicle. Approximately midway between the bumper 3 I and the rear of the scraper bowl, the beams 39, 3B and 3l, 3l are reinforced by means oi upper and

lower box beams

33 and 34 respectively which are welded between their associated beams, namely, the beam 33 connecting the beams 30, and the beam 34 connecting the beams 3i, 3|. Two vertically extending box beams 35 at the opposite ends of beams 33 and 3l! provide vertical struts. Each beam 35 extends between the beam 30 and the beams 3i on the same side of the vehicle. Stub axles 35 are mounted in the beams 35 and on these are mounted the rear scraper wheeis 3i. Preferably, a strut 33 is mounted between the mid portion of beam I3 and the mid portion of beam 33 as shown in Figs. l and 3. This beam is omitted from Fig. 2 so as to permit the showing of the ejector operating hoist. A beam 38 is positioned under each beam 30 and extends from beam I3 to beam 3l.

The support for the scraper at the front end is provided by means of a pull yoke 39 which is connected by means of a hitch it with a four wheel tractor, of which two parallel rear wheels 4I are shown mounted on an axle housing 42. It should be understood that this tractor is of the four wheel type having two wheels forwardly of and generally in front-to-rear alignment with the wheels 4I and provided with an engine at the front connected by the usual change speed mechanism and drive mechanism with the axle for driving the wheels 4I. The hitch 4D comprises a horizontally extending pivot i3 extending crosswise of the vehicle and mounted on a bracket 44 rigid with the axle housing 42. A bracket d5 which pivots on the pin 43 is connected by a horizontally extending pin 46 with a bifurcated bracket 41. The pin 46 extends in a fore and aft direction. The bracket 4l carries a vertically extending pin 47a which is embraced by a sleeve 4B which is oscillatable about the pin fila. Rigidly welded to the sleeve d8 are two goose neck shaped I-beams 49 which diverge rearwardly from the sleeve 48 and have their rear ends rigidly welded to a torque tube At opposite ends of the torque tube are rigidly welded the yoke arms 5I which extend rearwardly outside of and parallel to the side plates II of the scraper. Each of the arms 5I is of hollow box beam construction. The rear end of each arm 5I is pivotally connected by a hinge pin 52 with the scraper bowl. The pins 52 on opposite sides of the bowl are axially aligned. It will be noted that the hinge pin connection 52 of the pull yoke to the scraper bowl is located above and slightly to the rear of the hinge 2l which is just back of the scraper blade 6. It will be noted that the pivot 52 is approximately twofths of the distance from the bottom of the bowl to the top and this location has important eiects in the practical use of the scraper as will later appear.

The front gate or apron 53 is shown in its closed or lowered position in Fig. 1 and in its uppermost raised position in Fig. 3. This gate is side plates Il.

apagan made upof'parallel plates 54' between which are vvwelded spacers and reinforcing ribs 5B. The

plates,- 54 are welded. along their opposite parallel fore and' aft extending sides to vertically extending plates 51 which are positioned parallel to and just inside of the side bowl plates H. At its upper end, each plate El is welded to a short cylinder 58 which extends over the side plate ll of the bowl. To the outside of each of the cylinders-.58 is welded an arm which is just on the outside of and parallel to the bowl plate ll. It will be noted that the bowl plates ll. are

- clear and free of all exterior stiffening ribs at the zone traversed by the arms 59'frozn the posi-- tion of Fig. 1 to the position of Fig. 3 so as to permit the location of the arms 59 close to the Each of the arms 5S is pivotally connected by a hinge pin with a bracket 6| .which is welded to the reinforcing beam l1 on the sidewall ofthe scraper bowl. It will be noted that there is absolutely no obstruction on the inner face of the front apron 53 or on. the inner faces of the ejector portions 22a` and. 22h. This combined with the smooth inner faces of the bowl side walls H comprises a completely clean unobstructed interior wall construction for the scrapery bowl. This is very desirable.

A single hydraulic hoist` 6l is provided for moving the ejector fromthe position of Fig. 1 to the dumping position of Fig. 3. This hoist as clearly Y is pivotally mounted at 63 ona suitable bracket on the ejector portion 22h. Pressure fluid is supplied to the cylinder 6 la by the hydraulic sys tem shown in Fig. 4 for extending the hoist to move the ejector tothe dumping position ofFig. 3. In this manner, as the` telescoping pistons Gib and lc are of increasingly smaller diameter and the fluid supply to the hoist is substantially constant, the ejector moves progressively faster as it dumps the load. This is a single acting hoist and moves the ejector to a position shown in Fig. 3 Where the center of gravity of the ejec- --tor is forward of a verticalI plane through the Ahinge pivot 2l. secured between the y ejector portion 221)A and Two long helical springs 64 are suitable brackets connected to the side plates Il just above beams 3| and the ends of beam i4.

.These springs lie substantially upon beam I4 ,.v when the ejector is inthe position of Figs. 1 and 2. These springs are sufliciently loaded when the ejector is in the position of' Fig. 3 to cause the initial movement of the ejector in a clockwise direction from the position of Fig; 3 when thev pressure iluid is released' from the cylinder` v6Ia.` Thefsprings; 6A will:return the ejectorto theposition where its center of gravity is to the rear of a vertical plane through the hinge 2T after which gravity will return the ejector to the position. of` Fig. 1. i

Means is mounted on the,` pull yoke39, or more specifically on the torque tube 5!) for. liftingv the scraper bowl and front apron. This means comprises in Fig. 2 parallel spaced

hoists

65 and 66 for controlling the scraper bowl and a single hoist 61 located between them and paralleltov them for lifting the front apron. Each of lthese hoists is For instance, the;

hoist in Fig. 2v comprises; a cylinder 65a: on the near. side in Fig. 6 whichis closed at itsrear end by a plate` 65h which in turn is suitably secured by welding or bolting the-same to. a vertical planev 68 (Figs. 5 and 6) which forms a portionof a sheave housing. which is mountedv on the torque tube 56 and rigidly welded thereto. The top of this housing is indicated at 69 inthe upper right of Fig. 6- and a plurality of vertically. extending partition plates 10 are welded to the top 69, to the vertical plate 68 and tothe horizontal torque tube 5U providing av very strong' construction. Reciprocable in the cylinder 65a on the near side of Fig. 6 is a piston 65e which carries at its front or lefthand end a pulley head 65d. Rotatably mounted in the pulley head 65d are two pulleys or sheaves 'H and 12. Rotatably .mounted in the vertical partitions 'IllV of the sheave housing are the rear sheave 'I3 in foreandfaft alignment with forward sheave 1I and thev rear sheave i4 in alignment with forward sheave 1.2. The hoist 66 with itsy cylinder 66a on the far side in Fig. 6 has a similar construction. They pulley head 63d at the upper left has rotatably mounted in it the parallel sheaves 'l5 and 1.6. In the sheave housing to the rear the rear sheave Tl at the upper right is aligned with forward sheave 'i5 at the upper left-.and the'rear sheave 18. is aligned with forward sheave 'iSvwith these real` sheaves 17 and 18' being rotatably mounted between the vertical partitions 1,6;

A single cable 'i9 isv used on the sheavesy of both hoist 65 and 66 for lifting and lowering the bowl. This cable can be described briefly as having one end fixed to torque tube 59, extending around thesheaveson hoist 65 on the near side in Fig. 6 with a bight therein connected with the bowl at. 82 at the bottom of Fig. 6,' extending in a` corresponding manner around the sheaves on hoist 66 on the iar side in Fig. 6 with a bight therein` connected with the bowl at 8'! in Fig; 6, and having its other end also fixed in a corresponding manner to the torque tube 50. This construction is speciiically'described' hereinafter and' it should be understood. that the left side of 'Fig;. 6; is the frontV of thehoist mechanism and the right side is the rear. The single cable 19 inv Fig. 6 has onel end '59a fixed in a dead end Wedge socket (Figs. 5 and 6) on'. the torque tube 5) with said cable extending rearwardly throughthe plate 68: and'. bent around a reversings saddle 8l, (Figsj and 6.)'. carried by pl'atez68.

The cable then extends around the sheaves` on `hoist 65 onthe near side inA Fig. 6 while providing a bight for lifting yand lowering the bowl.

The cable 'I9 extends from the reversing saddle 8! along a horizontal lower run '19h extending v forwardly (toward the left in Fig. 6) and around the front sheave ll, extends rearwardly along a horizontal upper return run 19e andv then over rear'sheavel to' form a' downwardly extending moving bight 19daround. a: lift' saddle'82soscillatably mounted on. the box beam I2 at theI bottom. of Fig.: 6 with said beam!v connected to the front endof the scraper bowl. The cable 'i9 on the other endV of the bight 79d then extends upwardly and. around rear sheave 14, extends forwardly as an upper horizontal run 19e and around forwardv sheave l2, and extends rearwardly .as a lower horizontal run Isf and then through platev 68. The cable T9 then extends along torque tube 56 until it is properly aligned with the sheaves of hoist 66. on the far side in Fig. 6. After extending through plate 68, the1 cable- -19 coacts-withlthe structureinl Figs. 5 andfbyexkmoving bights 19d and '|92'.

. tending around a reversing saddle 83 on plate 68,

around a cross over saddle 84 fixed on torque tube Then, the cable 19 extends around the sheaves on hoist 66 on the far side in Fig. 6 While providing a bight for lifting and lowering the bowl.

' After leaving the reversing saddle 86, the cable 19 extends forwardly as a horizontal lower run 19g, extends around forward sheave 15 at the left in Fig. 6, extends rearwardly as a horizontal upper run 19h and over rear sheave 11, and then extends downwardly to produce the moving bight 19i passing around a lift saddle 81 at the bottom of Fig. 6 and fixed to box beam l2 opposite the lift saddle B2.

The cable 19 passes from the other end of bight 191 upwardly and over rear sheave 18, extends forwardly as a horizontal upper run 197A over front sheave 16, extends rearwardly as a horizontal lower run 19k, extends `rearwardly and around reversing saddle 88 on plate 68, and then extends forwardly and downi wardly with its end fixed into another dead end wedge 89v on torque tube 50;

By this arrangement, power strokes of the pistons 65e and 66o forwardly, impelled by pressure Afluid, will cause an upward pull on the moving cable bights 19d and 151' causing an upward lift on the lift saddles 82 and 81, thus causing the scraper bowl to rise. Because a single length of cable is used, the action of the

hoists

65 and 66 is equalized. Because of the reeving of the cable 19 over the 'plurality of sheaves just above indicated, the movement of the hoists 65 and E6 is 'multiplied greatly and gives a high lift to the scraper bowl. In one form of my device, using

hoists

65 and 66 having a power travel of not over seventeen inches, I find it possible to drop the scraper blade I6 fourteen inches below the grade line established by

wheels

31 and 4| or raise the same to a position twenty-eight inches above this grade line, or a total of forty-two inches of bowl travel in a vertical direction. Because the bowl is hung on the traveling bights 19d and 191 of the cable 19, the scraper bowl is enabled to "oat as the scraper is pulled forward during a digging or dirt spreading operation. This is a valuable feature of cable-operated scraper bowls,

- but to the best of my knowledge, has never been made possible before using relatively short lengths of cable such as I have provided in the At the same time, I have as much power appliedto lifting the bowl as would be found in a known type of cable-operated scraper utilizing a three-drum winch. In my case, the operating mechanism is very much simpler but provides all of the advantages of a floating scraper bowl.

The hoist B1 is mounted parallel to and between the hoists B5 and 66 for the purpose of operating the front apron 53. This hoist consists of a cylinder 61a which is closed at its rear end by the plate 61h which in turn is'bolted to the plate 68. A piston 61e is reciprocatable in the cylinder 61a by means of pressure fluid supplied to the rear end of the cylinder. The free end of the piston carries the head 61d in which are rotatably mounted three sheaves in parallel relationship, namely, 89, 90 and 9|. Aligned with these in the sheave housing are the

respective sheaves

92, 93 and 94 which are rotatably mounted in the partition plates 10. A cable 95 has one end 95a secured firmly at a dead end wedge socket 96v which is secured in the sheave housing. A run of the cable h then extends forwardly and around the pulley 09, then run 95e extends rearwardly and around pulley or sheave 92, then run 95d extends forwardly around sheave 90, then run 95e extends rearwardly and around sheave 93, then run 95f extends forwardly and around sheave 9|, then run 95g extends rearwardly and around sheave 94, after which the free end of cable 95 extends downwardly as indicated at 95h and is secured to an eye of a bracket 96 located on the lower mid central portion of the iront apron 53. It results from this construction, that when the piston 51C makes a power stroke forwardly impelled by pressure fluid admitted to the rear end of the cylinder 61a, the sheaves 89, 90 and 9| are carried forwardly causing a pull on the cable 95 which raises the apron 53 from the closed position of Fig. l to the open position of Fig. 3. It will be obvious from a study of Figs. 1 and 3 that the movement of the front apron 53 along with the cable 95 is in equal increments during the rst half of the movement of the apron upwardly because the cable 95 lies at against the front face of the apron 53 during this portion of apron movement. After the bracket 9S passes the point of tangency with the cable 95 indicated at 91 in Fig. 3, as the bracket 96 moves upwardly from the point 91, a given increment of lengthwise movement of the cable 95 causes a greater increment of front apron movement while the cable 95 is moving from a position of tangency to the path of the bracket 96' to a position almost radially of this path of movement. For instance, as viewed in Fig. 3, the cable portion 95h is almost in line between the top of pulley 94 and the pivot point S9 about which the front apron moves. Thus, as the apron moves upwardly its speed increases although the power applied to it will decrease slightly. This is in accordance with the necessities of the case because the load on the apron is less as it reaches its raised position.

The above described apparatus for operating the front apron 53, has an advantage similar to that described in connection with the scraper bowl, namely, that the front apron floats on the relatively short length of cable 95h while the scraper is being filled but without any great length of cable to become snarled up. At the same time, the multiplication of movement through the plurality of sheaves operated by the hoist 61 gives a great deal of cable travel for the operation of the front apron.

The hydraulic system for operating the various hydraulic hoists heretofore described is shown diagrmmatically in Fig. 4. The ejector hoist cylinder Gla is connected by line 98, with valve 99 mounted on the tractor body. The two hoists 65a and 66a have their cylinders connected by lines |00 and 0| respectively with line |02 which leads to control valve |03 on the tractor body. The apron hoist''la has its cylinder connected by line |04 with control valve |05 on the tractor body. These valves are located in a position where they may be operated 'by valve operating handles 99a., |03a and |05a. respectively located alongside the drivers seat |06 on the tractor. This is a very simple hydraulic system and one which is easy to keep in eicient operation. Each of the hoists is single acting. As mentioned previously, the springs 64 cause the initial return movement of the ejector from its raised position after which gravity causes the pistons 6|b and Ble to return into the cylinder 9, Bla. Obviously, the scraper bowl l2 moves downwardly under the action of gravity and the front apron 53 also returns from raised position to its lower or closed position under the action of gravity. This system makes it very easy to determine where leakages occur. For instance, if the scraper bowl tends to drift downwardly, if there is a leak in the hoist the oil will be leaking out of it and it will be simple to locate the trouble. If not, the only1 other place that this trouble could occur would be in the valve m3 so' that the mechanic would immediately lrnow where to go to work. Similar considerations apply toV the ejector. hoist and the front apron control hoist. It will be noted also .that only three flexible hoses, namely, 9e, H32 and mit, are

necessary between the tractor and the trailer. By mounting the valves and their control levers on the tractor, it is possible to arrange the control levers so that they are very convenient for the tractor driver to operate them.

The operation of my improved scraper should now be obvious. With the tractor moving forwardly, the operator actuates valve H33 to remove all pressure uid lrom the hoists (35 and 66, thus allowing the scraper bowl to drift downwardly until the blade IG dige into the earth. At the same time, the operator actuates valve itt to operate hoist 61 to open the front` apron 53 sufliciently to operate the scraper bowl to lll as desired. As the bowl nlls, the operator will eventually release all pressure fluid from the hoist 'El' allowing thev apron 53 to noat until Y itreaches the closed position of Fig. 1. .Depending upon the type of digging, the operator may lift the scraper bowl as it nils, or he may lift it after it becomes completely nlled. In any Case, eventually the operator aotuates the hoists 65 and 56 to cause the scraper bowl to be lifted to the carrying position of Fig. 1. The operator then runs the tractor to the desired location, after which he operates the hoist 5l to lift the front apron 53 and actuates the valve iis to send pressure fluid to cylinder lila so as to move the ejector from the position of Fig. 1 to the position yorV Fig. 3 to dump the load. Usually, dur ing such a dumping operation the .tractor and scraper are moved forward so .as to distribute ward, getting more of the scraper weight on ther tractor drive wheels. In an actual test Where the. total 'tractor weight was 18,200 pounds and the scraper weight (unloaded) was 22,300 pounds, there Vwas a slightly greater load on the drive wheels 4l than on the' rear scraper wheels 3i" When this equip-y in the unloaded condition. ment was loaded with 42,06@ pounds of earth, the actual weight on the driving'tires lil was 325,505

pounds' and the actual weight upon the Vrear wheels 3'! of the scraper was 36,000 pounds. A This will be recognized by those skilled in the art as a very exceptional distribution of the weight and one which is very favorable to a high traction on therear wheels of the tractor.

As has been mentioned previously, in this saine embodiment of my invention, it is possible to obtain forty-two inches of vertical travel'of the bowl which is very important when an operator has to lift himself out of trouble as when the equipment has so much material piled up in front of it that it cannot move. The bottom of the front apron 53 in the position of Fig. 3 is about six feet from cutting edge It. This helps when dumping a large mass of sticky soil.

Referring to Fig. 3, it will be noted that there is a space indicated by the dimension A between the lower side of the three hoists t5, t5 and 61 and the top of the torque tube 5G'. In an actual embodiment, this dimension A is about six inches and gives a clear vision of the operator, sitting on the seat of the tractor, toward the rear. 'This is very important if the operator is to watch the loading of the scraper and if he is to watch a pushing tractor acting upon the bumper 3 l The plate is cut away at its mid portion as indicated at 68 to give clearer vision.

Another feature of my scraper is the open top of the scraper bowl. lIt will be noted that this is unencumbered by any beams, pulleys, projecthat the reaction of the digging'or scraping op' eration rearwardly on the blade It is transferred, because of the proper location of the pivot 52, in an economical manner to cause a downward load on drive tires 4l.

of the digging action, the drive wheels 4l are loaded just when the load is most needed.

Referring to Fig. 1, it will be noted that the pin i3 which is the pivotal connection between the scraper and the tractor is located forwardly of a plane B extending through the axis of the axle housing l2 on which the drive wheels di are mounted. It is well known that when a tractor is trying to pull and unable to make progress, the front end' of the tractor tends to rear. In other words, there wouldv be a tendency for the pivot 43 to tend to move in the direction of the' arrow of Fig; l. It will be obvious that this movement is impossible because the entire load of the drive wheels provides moretractive effort for. loading power" in the combination of the tractor and the scraper.

It will be noted also that the scraper has an ex- A treinely low over-all height `and extremely low center of gravity. This gives a very good stability of thel scraper either empty or loaded. The scraper is very rugged and sturdy and of extreme simplicity and closely coupled to the tractor in frontr of it. Added to all this is a positive, fast and quickly responsive control of the working actions ofthe various operations of the scraper parts as described in connection with the descrip- Y tionof the operation of. my invention.

What claim is: l l l. In a digging and carrying scraper and a tractor fornmoving the same,.including a scraper` bowl having side walls and. a` bottom and an open front end and means for closing the same,

including wheel means supporting the rear Yend l of said bowl, ,including a drawbar having apiv o-tal connection between its rear end and said bowl, and including a hitch connection between This greatly aids in the loading action of the scraper and particularly when there is very little dirt loaded into the scraper bowl. In other Words, at the beginning 11 the front end of said drawbar and said tractor; the combination therewith of a hoist having relatively movable cylinder and piston members reciprocable in a fore-and-aft path, one of said hoist members being xed on said drawbar, the other of said hoist members being movable forwardly therefrom, sheave means carried by said movable hoist member, sheave means positioned in rear of said xed hoist member, a cable fixed at one end to said drawbar and reeved over both said sheave means to provide a movable run of said cable, with said cable extending beyond the fixed sheave means to form a connection with the forward end of said bowl.

2. In a digging and carrying scraper and a tractor for moving the same, including a scraper bowl having side walls and a bottom and an open front end and means for closing the same, including wheel means supporting the rear end of said bowl, including a drawbar having a pivotal connection between its rear end and said bowl, and including a hitch connection between the front end of said drawbar and said tractor; the combination therewith of two spaced parallel hoists, each hoist having relatively movable cylinder and piston members, each hoist having one of its members fixed on said drawbar and hav ing its other member reciprocatabie forwardly therefrom, a head carried by each said movable hoist member, two sheaves rotatably mounted in each movable head, a xed head positioned in rear of each xed hoist member, two sheaves rotatably mounted in each xedl head and in fore-and-aft alignment with the movable head sheaves of the associated hoist, the axes of ail of said sheaves being at right angles to the direction of hoist reciprocation, a single cable having one end ixed and then reeved on one hoist by passing around a iirst front sheave and around a first rear sheave and then downward and upward to provide a moving bight and then over a second rear sheave and forward around a second front sheave and then having a cross-over run to the other hoist and being reeved on said other hoist by passing around a rst front sheave and around a iirst rear sheave and then downward and upward to provide a moving bight and then over a second rear sheave and forward around a second front sheave and then to a device for xing the other end of said cable, and spaced xtures near the forward end of said bowl about which said moving bights pass.

3. In a digging and carrying scraper and a tractor for moving the same, including a scraper bowl having side walls and a bottom and an open front end, including an apron for closing said front end and having a pivotal mounting on said bowl for movement between a closed and an open position, including wheel means supporting the rear end of said bowl, including a drawbar having a pivotal connection between its rear end and said bowl, and including a hitch connection between the front end of said drawbar and said tractor; the combination therewith of three hoists mounted in parallel relation on said drawbar, each of said hoists having relatively movable cylinder and piston members, each of said hoists having its iixed member mounted on said drawbar and having its movable member reciprocate,- ble forwardly therefrom, a plurality of rotatable sheaves carried by each hoist movable member, a plurality of rotatable sheaves mounted in rear of each hoist xed member in fore-and-aft alignment with the sheaves of the movable member of the associated hoist, the axes of all of said sheaves extending at right angles to the direction ci hoist reciprocation, a cable reeved over the sheaves associated with the middle hoist of said three parallel hoists and having a moving run of said cable connected with said apron to raise .and lower the same, and a second cable reeved over the sheaves associated with the two outer hoists of said three hoists and having an equalizing run extending across said middle hoist position to equalize the action of said two outer hoists on said second cable, said second cable having a moving run connected with the forward portion of said bowl.

4. In a digging and carrying scraper including a scraper bowl having side walls and a bottom and an open front end and means for closing the same, including a frame supporting said bowl and having a frame portion above and in front of the front end of said bowl, and including wheel means supporting said frame; the combination therewith of two parallel hoists mounted on said frame portion, each of said hoists having a relatively movable cylinder and piston members reciprocable in a fore-and-aft path, each of said hoists having one of its associated hoist members fixed on said frame portion and the other of its hoist members being movable forwardly therefrom, fixed pulley means at the rear end of each oi said hoists, movable pulley means carried by each of said movable hoist members, a single length of flexible cable having its opposite ends nxed relative to. said frame portion, said cable being reeved over said pulley means associated with both of said hoists and providing two movable bights each passing downwardly and around an idler pulley mounted on the front end of the said bowl, whereby a lift of multiplied mechanical advantage is provided at all times substantially vertically upward to the front end of said bowl and said bowl oats on said bights of said cable and the lifting action of said two hoists is equalized through said cable.

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