US2256051A - Material excavating, loading, transporting and placing machine - Google Patents

Description

' J. :B. HAILE 2,256,051 MATERIALYTEXCAVATING, LOADING, TRANSPORTING, AND PLACING MQCH INE Sept." 16, 1941.

Filed Aug. 10, 1938 4 Sheets-Sheet 1 IN [/ENTOR Mww J. B. HAILE 4 Sheets-Sheet 2 Filed Aug. 10, 1958 Jan ,3. H4 BY 7 Y W 2@%% Sept. 16, 1941.

MATERIAL EXCAVATING, LOADING, TRANSPORTING, AND PLACING MACHINE Sept. 16, 1941. J. B. HAlLE MATERIAL EXCAVATING, LOADING, .TRANSPORTING, AND PLACING MACHINE Filed Aug. 10, 1938 4' Sheets -Sheet 3 I [NVENTOR I Z. BY 4 qflZr k 1- J A TTORNE K5.

J. B. HAILE 2,256,051

MATERIAL EXCAVATING, LOADING, TRANSPORTING, A ND PLACING MACHINE Sept. 16, 1941.

Filed Aug. 10, 1958 4 Sheets- Sheet 4 Illlllllll l llll TOR/VF K9.

I Patented Sept." 16, 1941 UNlTED STATES. PATENT OFFICE MATEmAL nxcAvA'rmG, LOADING, 'rnANsron'rmo. AND PLACING momma Jack B. Haile, Detroit, Mich, assignor to'Gar Wood igan industries, Inc., a corporation of Mich- Application August 10, 1938, Serial No. 224,131

(c1. a1- -1zs) Claims.

This invention relates to improvements in excavators, and particularly relates to the type in which a cutting blade is associated with -a dirt hauling scoop, arranged within a frame structure, and which is utilized as a means for transporting the dirt graded or scraped froma survface. g

Further, the present invention relates to the type of structure in which the scoop is pivotally connected directly to a main frame structure and is raised and'lowered by an upward lifting and a lowering of the forward end of the frame, and in which the tilting of the scoop for dumping is by a controlled adjustment about its supporting connection withthe main frame.

One of the primary objects of the present invention is to provide spring means at one end of the main frame which are compressed orloaded when the frame-is lowered to dig p sition and which willquickly jump or raise the frame,

in conjunction with a hydraulic cylinder, so that the cutting blade may be rapidly withdrawn from its bite in the earth. For the particular embodiment of the invention herein illustrated, the springs are located at the front end of the machine, but it is to be understood that they are not necessarily so placed, and may be positioned at the rear end, insteadpand when so placed will function with substantially equal success.

Another "object accomplished by the springs is that the size of the hydraulic cylinder may be reduced from that heretofore required, with the result that the speed of piston travel is increased without increasing the output of the hydraulic pump which supplies the fluid to the cylinder, and without increasing the operating pressure of the hydraulic fluid.

A further object of the present invention isto provide -a construction in -which the gate-sub porting arms are positioned inside of the side walls of the pivoted scoop but are not mounted on, the scoop side wall, the pivotal mounting oi these gate-supporting arms being on stationary side walls and at points above'andvery subetantially rearwardly of the pivotal points about which the scoop moves: to provide ir'iont'g atefa, supporting arms of relatively long length and positioned so'th'at when the gate 13 1mm it'wiil be in load supporting position and at these-me time the gate may be made to ride or float along on the top of soft material which is loaded into the scoop; to provide a construction in which the width of the scoop most closely ap proaches the overall width of the entire" ma chine; and to provide a machine of this class inwhich the material hauling scoop is of maximum capacity for the overall width of the machine.

An illustrative embodiment of this invention is shown in the accompanying drawings, in

which:

Fig. 1 is a view inside elevation with the ma- '-chine in load transporting or hauling position in full lines and with the apparatus shown in' dumping position in dotted lines.

Fig. 2 is an enlarged fragmentary sectional view taken on the line 2-2 of Fig. 1, looking in the direction indicated by the arrows.

Fig. 3 is an enlarged fragmentary sectional view taken along the line 3-3 of Fig. 1, looking in the direction indicated by the arrows.

Fig. 4 is an enlarged fragmentary sectional view taken along the line l-lof Fig. 1, looking in the direction indicated by the arrows.

Fig. 5 is a top plan view of the machine shown I in Fig. 1.

' Fig. 6 is an enlarged fragmentary sectional view taken along the line 6-6 of Fig. 1, looking in the direction indicated by the arrows.

' Fig. 7 is a view in side'elevation of the machine in digging or excavating position.

Fig. 8 is a fragmentary view, in side'elevation,

with a portion thereof broken away, showing a modified form of gate lifting means which permits the gate to ride or float on'the surface of the ground being excavated.

Fig. 9 is an enlarged view partly and partly in elevation of one of the spring units in'fully compressed position.

Fig. 10 is an enlarged fragmentary view, partly in section and partly in elevation, of the upper end of the unit shown in- Fig. 9 but with the spring in extended position. 4

Fig. 11 is an enlarged fragmentary view, partly in section and partly in elevation, of the lower end of the unit shown in Fig. 9, but with the spring in extended position. Machines of the character herein shown and described are usually attached to tractors or the like which furnish the motive power for pulling i the excavating machine. Such tractors are equipped with a hydraulic pump which is connected to the various hydraulic controls of the excavating machine for operating the same. Heretofore in the use oi machines of this charicter the scoop is adjusted to'dissl s position ahd' pulled into the earth so as to on the bowl or scoop with the material. As the digging blade of the scoop passes down into the earth and the .bowl or scoop fills up with material the tractive power required to pull the machine becomes in section I very great and when the pull of the machine upon the tractor is sufficient to practically stall the tractor, it becomes necessary to raise the cutting blade out of the earth to prevent stalling of the tractor. To doso means operation of the hydraulic pump and this throws a still greater horse power load .upon the tractor, the result of which is that the tractor sometimes stalls.

In the present'machine means are provided for 1 storing up power, these means in the present form illustrated being a of relatively heavy helical compression springs.- In the use of this machine, the hydraulic pump is actuated. to

. compress the springs at the time when there is very little load on the scraper blade and therefore the tractoris well able to not only pull the machine, but at the same time operate the hydraulicpump for compressing the springs. Compression of the springs is also aided by the drawbar pull acting through a leverage arrangement and by the weight of the machine. As the scoop scraper blade digs into the earth and fills the scoopor keeps taking a heavier bite into the 1 stored in thesesprings will thereupon tend to raise themachine upwardly and thereby with- 3 draw the cuttinglblade and do so with very little help from the hydraulic pump which is attached to the lifting control. Furthermore, oftentimes Y in'certain characters ofearth all that is necessary to do is merely operate the hydraulic control 1 until the springs are sufiiciently compressed to bring the scraper blade into contact with the groimd. Thereupon the drawbar pull aided by the angular slope of the scraper blade digging into the earth will tendto pull the machine down and thereby compress the lifting springs without material operation of the hydraulic pump to which the lifting control is attached. It will thus be seen that in some instances it is possible to store up energy in, the lifting springs without throwing very .much additional horse power load onto the tractor.

The net result of this arrangement is that a bigger or greater capacity excavating machine may be handled by a smaller tractor than heretofore and thus efiect a very substantial economy in operation, as well as lessening the investment of capital in the original equipment.

Furthermore, by having a considerable amount of energy stored up in the lifting springs, it is readily possible to disengage or partially disengage the cutting blade from the earth just' prior 1 to the stalling of the tractor to which the machine is attached which' in other instances without the lifting springs would be totally impossible. The quick action of the lifting springs 1 as compared tp the hydraulic cylinders usually 1 employed for this purpose is extremely advantaeous and results in a much' more flexible machine 7 Although -in the present embodiment illustrated the lifting springs are mounted at the front oi the excavating machine, the placing of the springs being merely a matter of preference.

In the construction shown in the drawings the improved excavating machine comprises a. pair of spaced substantially parallel side frame members l and it, one at each side of the machine which are connected adjacent the front and rear ends by cross frame members I! and I8 respectively, thus forming a substantially square frame when viewed in plan as in Fig. 5 of the drawings. The rear ends of the side frame members II and i5 extend rearwardly beyond the cross frame member l8 and are provided with inwardly extending stub axles upon which ground wheels I! and 20 are journaled.

The cross frame member ll ls tubular and extremely rigid in construction and at its medial point is provided with a forwardly and upwardly extending arm 2| welded or otherwise rigidly se-.

cured thereon. The member llis also provided with a pair of aligned, rigidly mounted forwardly extending, brackets 22 and 23, positioned one at each side of and closely adjacent to the base of the arm 2|. The brackets 22 and 23 have pivoted thereto spaced parallel arms 24 and 25, respec- :tively, which are integrally formed on a generally forwardly extending triangular shaped member 26 which converges toward the front and the forward end of which is rigidly secured as by welding to the top end of a generally upright strut 21 of semi-cylindrical cross-sectibn'. As shown .most clearly in Fig. 4 of the drawings, the lower endof the strut 21 is rigidly mounted on a fitting 28, the lower end'of which is provided with a cross-pin 29 upon which is pivoted 1 a knuckle member 30. The knuckle 36 is also provided with a cross-pin 3i positioned at right angles to the pin 29 add which is mounted in a pair oi. upstanding spaced parallel ears 32, in-

tegrallylformed on the top end of a vertically disposed king-pin 33. The king-pin 33 is pivotally mounted in, the middle of arelatively short i'ront axle 34, upon the opposite ends of which are journaled ground wheels 35 and 36.

The front axle 35 is provided with a forwardly extend- 111g tongue or draw-bar 31.

Means are provided for controlling the pivotal movements of the strut 2i and member 26 integrally formed therewith relative to the arm 2i and side frames I 5 and I 6 and comprise a hydraulic ram generally designated 38 in Fig. 1

of the drawings. I'hehydraulic ram 38 comprises a cylinder 39 the lower end of which is pivotally mounted on a cross-pin 40 carried by the fitting 28 and the position of, the parts is such that the cylinder 39 is partially surrounded by the strut 21 when the apparatus is in the position shown in Fig. l. The cylinder 39 is provided with a piston'having a piston rod M connected thereto and which extends through a suitable stufling box in the upper or top end of the cylinder 39 and the outer end of which is pivotally mounted on a cross-pin 42. The pin 42 is carried by the forwardly extending arm 2| of the main frame, the details of the connection being shown most clearly. in Fig. 3 of the drawings.

The opposite ends of the hydraulic ram cylinder 3! are provided with hydraulic conduits 43 which are connected to a source of fluid under the tractor or motive power which moves the excavating machine, by flexible hose lines.

1 end of the vehicle, it will be readily understood that this same action may be secured by having the lifting springs acting between the cutting The fitting 28 at the lower end of the strut 21 is provided with a forwardly extending bracket 44 which carries a cross-pin 45, the opposite ends of which extend from the sides of the bracket and upon which are mounted the lower ends of a pair of spring units generally designated 33. The spring units 43 are of identical construction, therefore a detailed description of one will sufiice for both. As shown most clearly in Figs. 9, and 11 of the drawings, each of the spring units 43 comprises a circular head or cap member 33 which is pivoted one on each end of a cross-pin 50 which is mounted transversely of and to the forwardly extending arm 2|. The cap member 90 has a concentrically positioned axially extending rod or plunger SI rigidly mounted thereon which slidably telescopes within a bushing 32 which is welded into the top end of a sleeve member 93. The sleeve 33 is integrally formed on one end of a collar ll, the other end of which is provided with a similar oppositely extending sleeve 95. The collar 34 has a radially extending annular flange 96 integrally formed thereon midway of its axial length which serves as a seat for one end of a helical compression spring 91. The other end of the spring 81 seats against the under side of the head member 90 and the spring is loosely guided by a sleeve 58 which is welded to'the head 90, concentrically with respect to the rod ii. The outside diameter of the guide sleeve 33 is slightly less than the inside diameter of the spring convolutions. The sleeve also serves to protect that part of the rod SI which slides within the bushing 92 from much dirt and. dust which otherwise would cause extensive wear and which would interfere with itssliding movement.

As shown most clearly in Figs. 9 and 11, a lower circular head member has a concentrically positioned, axially extending tube no rigidly welded thereto which has sliding telescoping fit tudinally of the side frames I5 and It. When the scoop Ill is in normal position, as shown in full lines in Fig. 1 of thedrawings, the rear end thereof is rigidly supported by a ledge or stop I50 which rests upon the rear cross member I 3. a

The construction, mounting, and arrangement of the hydraulic rams I I8 and II are identical and, therefore, a detailed description of one will suffice for both. 'As shown clearly in Figs. 1 and 7, the rear or lower end of the cylinders of the hydraulic rams are pivotally mounted to the side frames by upstanding brackets I and HI, respectively, the upper ends of which carry pivot pins I22 and I23, respectively, upon which the respective cylinders are pivoted.

The cylinder of the hydraulic ram H8 is provided with a piston and a piston rod I24 conwithin the sleeve 33 and is of such length as to in slightly spaced relation to the bushing 32 when the unit is in fully telescoped position as shown in Fig. 9. The inside diameter of the tube IIIII is slightly greater than the outside diameter of the rod 9| so that the rod can freely slide therethrough as is also shown in Fig. 9. The head member 39 also serves as a seat for the lower end of a helical compression spring Ill, the upper end of which seats against the under side of the flange 33. The springs 91 and III are of such strength and construction that they will support a major part of the weight of the machine when fully loaded as will be hereinafter more fully explained.

The side frame members l5 and I3 have rigid y secured theretovertically disposed, longitudinally extending, side wall plates II. and III, respectively, by angle bars H2 and H3, respectively, one flange of which is attached to the top surface of the side frame members I! and I6 and the other flange of which is welded or otherwise rigidly secured to the side plate members Ill and III. Betwen the side frame members I! and- I3 is pivotally mounted a carrying-scoop III on a pair of transversely disposed mountings IIS and II which are of identical construction and one of which is most clearly illustrated in Fig.2

. of the drawings.

The scoop III is provided with side walls, a

- rearend, and a bottom integrally formed, the

front of the scoop being open, and the leading edge of the bottom being provided with an inclined cutting blade I" after the usual manner of scoops of this character. Means are provided nected thereto, one end of which protrudes from the other end of the ram cylinder through a suitable stufling box. The outer end of the piston rod I24 is pivoted on a pin I25 which is mounted in a bracket I26 rigidly secured at the scoop III at a point above and to the rear of the point of pivotal mounting. Suitable hydraulic lead fines I21. and I28 are connected to and communicate with opposite ends of the ram II3 for conducting fluid under pressure to opposite ends of the ram cylinder as desired. The hydraulic lead lines I27 and I23 are of flexible material adjacent to their respective ends of the hydraulic rams in order to permit movement of the rams.

Means are provided for holding the dirt or other loose material in the scoop H4 and comprises a forwardly inclined gate I30 extending transversely across the front end of the bowl and provided at each end thereof with rigidly secured upwardly and rearwardly extending arms I36 and I32. The rear ends oi the arms I3I and I32 are pivotally mounted on pins I33 and I31, respectively, which are mounted upon ,the inner sidesv of the side walls III! and III,

respectively. Reinforcing plates 23! are welded or otherwise rigidly secured to the inner-side walls I III and III and extend between the pivots IIS and II 6 which support the scoop I I4 and the pivots I33 and I3, respectively, upon which the rear end of the gate supporting arms are secured.

The side walls H0 and III extend'forwardly of the front edge of the bowl member or scoop Ill so as to form side apronsbetween which the gate I30 is freely movable, the side aprons orforwardly extending portions of the side wall serving the purpose to prevent soft, loose material, such as sand, pushing out around the sides of the 1 scoop and for aiding in directing and holding the sand so that it is gathered up and fed into the scoop.

By having the gate-supporting arms I3l and I32 secured to the stationary side wall as distinguished from having them pivoted to the side walls of the scoop, it is possible to have the gatesubporting arms of greater length without having the gate I30 interfere with the front cross frame member I'I during dumping movement of the scoop.

I Byhaving the gate-supporting arms relatively long and the gate inclined forwardly at considerable of an angle, it is possible, when loading soft material, to let the gate float or ride along on the surface of the material being scraped up and put for rotating the scoop Ill about its pivotal connections lll and H3 and'comprise a pair of V hydraulic rams I I3 .and Ill, moimted one at each into the'scoop. This riding of the gate on the surface of the soft material aids materially in loading it into the scgop or scraper.

Means are provided for raising and lowering the gate I3ll'and comprise a hydraulic ram 135 pivoted on a pin I36 to the forwardly and upwardly extending end I3'I of the arm 2| and which has its piston I38 pivoted by a pin I39 to a bell crank lever I40 pivoted at I to an upstanding bracket I42 which is rigidly mounted onthe arm 2I and front frame cross member II. The

working in 'hard or stony ground, it is very helpful to be able to quickly jump the scraper blade upwardly, and the combination of a relatively small, fast moving cylinder ofthe hydraulic ram unit and the spring units 48 operates most satisfactorily. The extent to which the forward end of the frame is elevated may be controlled by outer end of the other arm of the bell crank I40 is pivoted at I43 to one end of a rigid link I44, the other end of which is pivoted to the medial part of the gate I30. With such a construction it is possible to not only lift the gate away from the front end of the scoop I I4, but also "power down or, in other words, close the gate by hydraulic power.

In the modification shown in Fig. 8 .of the drawings, the bell crank lever I40 is connected to the gate I30 by a flexible connection such as a chain I45, by the use. of which it is possible to raise the gate by hydraulic power, but-the gate will float or ride along on the surface of the ground when loading soft material and will close by gravity when permitted by its controls. This is particularly useful when it is desired to have the gate-float or ride along on the surface of loose materialbeing loaded into the scoop II 4.,

, v Hydraulic lead lines- I46 and I4! are provided which communicate with opposite ends of the hydraulic ram I35 and which are connected to a source of fluid under pressure as heretofore described with respect to the other hydraulic operating units of this machine. I

.In the operation of this machine, when it is desired to load earth or other material into the scoop H4, fluid under pressure is admitted into forward edge ofthe scoop H4 and thus cause the controlling the application of the hydraulic medium'to the hydraulic mechanism 38.

Dining the loading movement of the scoop, the

gate I may be raised, depending upon the charactor of the ground being worked. In soft material, such as sand, it is sometimes desirable to let the gate ride along on the top surface of the material being gathered into the scoop. At other times it is desirable to raise the gate as shown in i Fig. 7 of the drawings so as to leave a wide, free opening for thematerial to pass between the forwardly extending side aprons of the side walls III and Iii and be raised by the cutting. edge of the blade ii 8 into the scoop i I4.

During other loading conditions, it is desirable to raise the gate only slightly away from the material being loaded to pass through arelatively narrow slot into the scoop and, as the scoop fills up, this material will roll forwardly and part of it be supported upon and carried by the for-' wardly inclined gate I30.

' In installations where the gate is connected to the bellcrank I by the stifi link Ill, it is posthe hydraulic ram 38 at the upper end thereof which forcesthe piston therein downwardly, thus compressing thesp'ring-units 48. This moyement causes the front wheel structure to move outwardly with respect to the frame of the machine as shown'in Fig. 7 of the drawingaand thereby lower the side frames and scoop II4 to a digging- 'position,-that is, to a point where the cutting blade III engages with the ground. In diggin some characters of earth, it is possible to start the digging by first rotating the scoop forwardly and thus cause the cutting blade I" to engage the earth. Due to the angle of the cutting blade II 1,- the engagement "with theearth tends to draw 7 the whole machine downwardlinthat is, causes the earth cutting edge to bite into the groun and thus theforwardmovement of the machine during its scooping operation will tend .-to compressthe spring units 48 with substantially very little or no aid from the hydraulic ram 38. ,Com-. pression of the spring units 46 stores up a coni siderable amount of energy therein and the sible to close the gate at any time by applying I hydraulic medium under pressure to the ram I35 and thereby "power down the gate to a closed position. Under other conditions, it is most desirable to have the gate close by gravity and in V such instances the gate is provided with a flexible connection such .as the chain I45, both forms of connecting means being provided with the machine when supplied to the customer.

When the mop III has been fully loaded, the

machine is raised to the position shown in-full 'tostick within the scoop, the hydraulic controls strength of these springs is such-that when the scoop I I4 becomes nearly filled or, if it is biting too deeply into the earth, the scoop may be quickly raised by merely opening the valve of the hydraulic ram 38, thereby permitting the spring units: 46 to raise the machine tothe position shown in Fig. 1 of the drawings.

Also by the use of the resilient spring connecting means 46 which tends to urge the forward end of the. main frame-upwardly, a smaller bydraulic cylinder may be used in the present structure than in the prior structures without increas ing the working pressure. Furthermore, the

smaller-cylinder results in increased speed of movement'without increased hydraulic pump output, which feature is particularly desirable in the case of this machine. v When scraping up the dirt during loading of the scoop, particularly when Another distinct advantage of'having the gate maybe operated rapidly to power down the front end of the machine afew inches, thereby comprising the lifting springs, and then quickly release-thahydraulic pressure. Thereupon the liftingspringswilliumpthemachineup,andby quick repetition of this action, it is possible to vigorously shake the scoop and thereby dislodge any sticking material.

.By having the gate Ill molmtedupon role,- tively' long arms, the pivot pointsof' which are upon the stationary side walls of the machine, as distinguished from being pivoted upon the side .walls of the movable 80001). the gate may be positione'd closely adjacent to the front end of the machine, i. e. to the front cross member "and not interfere therewith upon rotation of the scoop,-as would be the case if-the ga ing arms'were pivoted to the side walls of the scoop H4, and thereby movable when the scoop is rotated for dumping.

supporting arms mounted on stationary pivots,

lies in the fact that the gate opening is set in relation to the surface of the ground and will, not be disturbed or changed by rotative movement of the scoop on its pivots for adjusting the angle of jacent one end of said frame, resilient means interposed between said wheels and said frame for normally urging said scraper element and bowl upwardly, and hydraulic means for elevating and lowering said scraper element relative to said wheels.

2. In a machine of the class described, a frame, a scraper element mounted on said frame, wheels adjacent one end of said frame, resilientmeans interposed between said wheels and said frame for normally urging said frame upwardly, and hydraulic means for elevating and lowering said frame relative to said wheels.

3.'A scoop scraper of the character described comprising a main frame, supporting ground wheels at the rear thereof, a rigid extension at the front thereof, link means pivotally attached to the extension of said main frame, front ground wheels pivotally secured to said link means, a material load receiving bowl and scraper element carried by the main frame, resilient means acting between said extension and said front ground wheels for normally urging said frame upwardly, and other means acting between the frame and front ground wheels for elevating and lowering the front end of said main frame. a

4. A scoop scraper of the character described comprising a main frame, supporting ground wheels at the rear end thereof, a rigid extension at the front end of said frame, a material load receiving bowl and scraper element carried by the main frame rearwardly of said extension, a steerable wheel at the front end of said frame, resilient means acting between the extension and said steerable wheel for resiliently mounting said frame with respect to said steerable wheel and for normally urging said frame upwardly, adjustable means interconnecting the extension and said steerable wheel, a link means forming a triangle with said adjustable means, and said extension, all of which are pivoted to permit the shape of the triangle to be changed, and means for adjusting said adjustable means to alter the shape of the triangle and thereby vary the wheel base of said scraper.

5. In a scraper, relatively movable front and rear frames each being wheel supported, a scraper blade suspended from one of said frames and being movable toward and away from the ground by relative movement of said frames, a hydraulic jack for relatively moving said frames, and spring means cooperating with said jack to assist the same in raising said blade and to cushion the lowering movement thereof.

6. In a scraper, a front framehaving supporting wheels and extending rearwardly therefrom, a rear frame having supporting wheels and extending forwardly therefrom, a load carrying bowl suspended from one of said frames and having a scraper blade associated therewith, said frames being articulably interconnected at their respective rear and front portions and one of said frames having a rigid extension projecting beyond the axis of articulation and in proximity to the other frame, elevating means coacting with said extension and with said other frame to produce relative articulation thereof whereby said bowl and blade are raised and lowered, and a spring cooperating with said elevating means to assist the latter in raising said bowl and blade.

7. In a scraper, relatively movable front and rear frames each being wheel supported, a bowl suspended from one of said frames and having a scraper blade movable toward and away from the ground by relative movement of said frames, jack means for relatively moving said frames to raise and lower said bowl and blade, and spring means cooperating with said jack means to assist the same in elevating said bowl and to cushion the lowering movement thereof.

8. In a scraper, relatively movable front and rear frames mounted for transportation along the ground, a scraper blade suspended from one of said frames, a hydraulic jack interposed between said frames for relatively'moving the same to raise said blade, and a series of compression springs cooperating with said jack to assist the same in elevating said blade and to cushion the lowering movement thereof.

9. In a scraper, pivotally interconnected front and rear frames mounted for transportation along the ground, a load receiving bowl suspended from one of said frames, a hydraulic jack having a cylinder pivotally attached to one of said frames and a plunger pivotally attached tothe other frame, said cylinder and plunger being relatively movable to elevate said bowl, and compression springs disposed about said jackand coacting with said cylinder and plunger to assist the jack in raising said bowl.

10. In a scraper, a front frame having supporting wheels and extending rearwardly therefrom, a rear frame having supporting wheels and extending forwardly therefrom, a scraper blade suspended from one of said frames, said frames being articulably interconnected at their respective' rear and front portions and one of said frames having a rigid extension projecting beyond the axis of articulation and in proximity tothe other frame, elevating means coacting with said extension and with said other frame to produce relative articulation thereof whereby said blade is raised and lowered, and a spring cooperating with said elevating means to assist the latter in raising said blade.

JACK B. HAILE.

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