US2789377A - Dolly for digging and carrying scraper - Google Patents

Description

April 23, 1957 s. E. ARMINGTON 2,789,377

DoLLY FoR DIGGING AND CARRYING scRAPER Filed Sept. 16, 19,52 2 SheetlsfShset 1 INVENTOR.

Jrfwfmr Ann/varon April 23, 1957 s. F. ARMINGTON 2,789,377

DoLLY RoR DIGGING AND CARRYING scRAPER Filedsept. le. 1952 2 sheets-snm 2 Eig. E

INVENTOR. JMW/1m' E ARM/,varon ATTORNEYS United States Patent O DOLLY FOR DIGGING AND CARRYING SCRAPER Stewart F. Armington, Willoughby, Ohio, assigner, by mesne assignments, to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application September 16, 1952, Serial No. 309,827

16 Claims. (Cl. 37-126) This invention relates to improvements in weightsupporting dollies, but more particularly to a weightsupporting dolly for a digging and carrying scraper.

One of the objects of the present invention is to provide a weight-supporting `dolly for a digging and carrying scraper for reducing the weight on the front and rear wheels of the scraper to -an allowable limit for over-thehighway travel.

Another object of the present invention is to provide a ground-engaging Idolly for detachable securement to a digging and carrying scraper bowl.

Another object ofthe present invention is to provide la ground-engaging dolly secured to the bowl or drawbar of a digging and carrying scraper wherein said bowl and drawbar are hinge-joined so that lthe dolly will support part of the scraper weight.

Another object of the present invention is to provide a ground-engaging dolly for a digging and carrying scraper having 1a vertical float to allow for bumps encountered in the road wherein such float is provided by the scraper bowl raising and lowering mechanism ot' the digging and carrying scraper.

Another object of the present invention is to provide a ground-engaging dolly for a digging and carrying scraper idetachably secured to la scraper bowl which can be raised and lowered so that the bowl and dolly can be raised to lift the dolly out of ground engagement for easy assembly and disassembly with the bowl.

Other features of this invention reside in vthe arrangement and design of parts for carrying out theirfappropriate functions. Other objects .and Aadvantages of this invention will be apparent from the accompany-ing drawings and description and the essential features will be set forth in the appended claims.

In the drawings,

Fig. l is a side elevational view of a tractor-drawn digging and carrying scraper equipped with a ground-engaging, weight-supporting dolly for supporting a portion of the scraper weight to reduce the load on the wheels supporting the front of the scraper (the rear wheels of the tractor), the rear wheels of the scraper and the front wheels of the tractor;

Fig. 2 is a front view of the dolly, enlarged, taken along the line 2 2 of Fig. 1 with its upper end secured to the lift beam of the scraper bowl (shown fragmental- 1y);

Fig. 3 is a longitudinal vertical sectional view enlarged through the scraper dolly and the lift beam of the bowl taken along the line 3--3 of Fig. 2;

Fig. 4 is a horizontal sectional view taken along the line 4-4 of Fig. 3 through one of the pair of wheels on the dolly; v

Fig. 5 is a sectional view similar to Fig. 4 but showing the two extreme limited pivot positions of a pair of wheels in soli-d line and dot-dash line positions;

Fig. 6 is `a vertical sectional view enlarged taken along line 6-6 of Fig. 4 through the limited pivot connection;

Fig. 7 is a fragmental front View of a modification of the dolly supporting post structure of Fig. 2;

Fig. 8 is :a side elevational view of a portion of Fig. 1 but showing the weight-supporting dolly detachably secured to the pull yoke instead of to the bowl lift beam; while Fig. 9 is `a front view of the scraper bowl with two dollies detachably secured to the scraper bowl in a different manner than that shown in Figs. 1, 2 and 3.

While my invention might be adapted'to various types of machines :and various types of digging and carrying Scrapers, I have chosen to show the same .as applied to a specific digging and carrying scraper as shown in Fig. 1 of the drawings. It will also be apparent, as this description proceeds, that the ground-engaging weight-supporting dolly of this invention can readily be used with the digging and carrying scraper disclosed in the U. S. patent application Ser. No. 111,496, led August 20, 1949, by William J. Adams, entitled Scraper, now Patent No. 2,674,815, and U. S. patent application Ser. No. 287,772, led May 14, 1952, by Edward R. Fryer and William I. Adams entitled Digging and Carrying Scraper.

The digging and carrying scraper in the above mentioned applications and in the present disclosure have many structural features in common that should be described before the present invention in a dolly is set out in detail. The digging and carrying scraper, shown generally at 10, is pulled by a tractor 11 having rear drive wheels 12 serving also as supporting wheels for the front of scraper 10. Then, the weight of the scraper is carried by the front wheels 12 and the rear wheels 13, of course. It should be understood that the front of the scraper may be supported by other types of wheels tlran the rear drive wheels 12 of the tractor 11, if the scraper is driven forwardly by other power means.

The load-carrying member of the scraper is the scraper bowl 14 having spaced side walls 14b, 14h, having a digging blade 15 at its lower edge and having an open front with :an apron 16 movable about a pivot at axis 16a between a raised and lowered position for opening and closing said open front.

Means are provided for supporting the bowl 14 in a suspended position between the front and rear wheels 12 and 13. The rear of the scraper bowl 14 -is secured to the axle for rear wheels 13. A pull yoke 17 is pivotally connected .at its front end by a hitch to the front sup porting wheels 12. The pull yoke 17 extends rearwardly therefrom and divides into two pull arms straddling the opposite lateral sides 14b, 14b of the scraper bowl 14 with each pull arm having its rear end connected on a transverse pivotal axis 17a to one of the scraper bowl side walls 14b. The scraper bowl 14 is movable between fa lower digging position with the scraper blade digging into the ground and a higher carrying position with the blade 15 in an elevated position. The pull yoke 17 and bowl 14 move up and down together since they have a common pivot 17a. This provides a hinge joint between the pull yoke and bowl.

Means is provided for raising and lowering the bowl between these positions. In the present disclosure and in the aforementioned U. S. patent applications, this means takes the form of a hydraulic hoist means 1S cornprising one or more hydraulic hoist members. This hydraulic hoist means 18 is connected to the front of the scraper bowl 14 by a flexible cable 19 for permitting a limited amount of vertical up-float of scraper bowl 14 when the Schaper blade 15 is digging while the bowl 14 is in its lowered position. The aforementioned U. S. patent application Ser. No. 287,772, entitled Digging and Carrying Scraper, filed May 14, 1.952, by Edward areas?? R. Fryer and William I. Adams, presents a slightly different type of hydraulic hoist means for raising and lowering the scraper bowl by ia lever and connecting links wherein the links have elongated slots to permit a similar type of up-oat. The hydraulic hoist means in any of the aforementioned structures is connected to a pressure fluid supply for expanding or contracting said hydraulic hoistl means for controlling raising or lowering said scnaper bowl 14. This pressure fluid supply can take the form of the structure shown in the copending U. S. patent application Ser. No. 309,514, tiled September 13, 1952, by William I. Adams and Edward R. Fryer, entitled Hydraulic Power Unit.

Means is provided for controlling, the ow from the supply to the hydraulic hoist means 1S with said control means being preferably located near the scraper operator on the tractor l1 for easy manipulation. This control means has a control position wherein the hydraulic fluid will (l) expand the hydraulic hoist means to raise the bowl 14, (2) be prevented from leaving or entering the hydraulic hoist means for maintaining the bowl at a given level and (3) will freely flow into or out of the hydraulic hoist means 18 depending upon the force exerted upon it by the scraper bowl 14 in moving vertically up or down and will drain and contract the hydraulic hoist means 18 to lower the scraper bowl 14.

The modern day digging and carrying scraper is a large, heavy piece of machinery and its heavy weight has created problems. When the scraper is transported over the highway from one job location to another, it is of course generally empty, but even though it is empty, the axle loads are excessive and frequently are larger than a number of States will permit on their highways. Many States will not permit loads over 18,000v pounds per axle while a large scraper of the type shown in Fig. l may have a 22,000 pound load on the axle of tractor drive Wheels 12 and a 16,800 pound load on the axle of rear wheels 13. When a weight-supporting ground-engaging dolly is secured to the scraper between the front and rear wheels 12 and I3, it supports a portion of the scraper weight to reduce the load on the wheels 12 and 13. This scraper dolly divides the empty scraper weight overv more road wheels and tires while having other de'- sirable advantages to be brought out more in detail hereinafter. The load in the above-mentioned instance then becomes 15,600 pounds on the axle of tractor drive wheels 12 andl 11,800` pounds on the axle of the rear wheels 13 while the scraper dolly 21 carries 12,200 pounds. Of course, the front axle ofthe tractor now carries 11,970 instead of the 12,000 pounds it carried before. This solves the load limit problem in many States.

The dolly is readily detachable from the scraper so that it will notV interfere with the digging operation when the scraper is used for its normal purpose. The vertical float of the dolly 2l permits it to move vertically out' of an in-line or even-level position with the wheels 12, 5 3 when bumps are encountered, or when the dolly is to be assembled onto or removed fromv the scraper. This floating action is made possible by the connection between the hydraulic hoist means 18 and the bowl taking the form of a flexible `cable 19, a slotted link, or other lost motion connection and by the control means for the hydraulic hoist means 18 when the hydraulic fluid can freely flow into or outof the hydraulic hoist.

The preferred form of scraper dolly construction is shown in Figs. l to 6 inclusive. In Fig. 2, the dolly 21 has a lsupporting post 22 of box beam -construction with a connection at its top end for removable attachment to the bowl lift beam 14a, also of box beam construction, extending across the front upper edge of the scraper bowl 14. The front and rear walls of the post' 22 extend upwardly to for-m front and rear plates 22a, 22") adapted to be squeezed into engagement with the front and rear walls of the lift beam 14a by clamp bolt 23. A supporting ledge 2d is secured tothe post 22 to engage the lower face of the lift beam 14a for insuring that the post 22 will not be tilted too far from the vertical in Fig. 2 when the bowl weight is applied to the dolly.

A wheeled carriage 25 has a cross beam 25a pivotally attached :at 26 to the lower end of post 22 with the pivot permitting oscillation about the horizontal axis to allow for unevenness in a road surface. The carriage 25 has two pairs of wheels 27, 27 with each pai-r pivotally mounted on opposite sides of the carriage cross beam 25a for limited movement about a vertical axis. The pivotal mounting for one pair is shown in Fig. 6 wherein a pivot boit 2S secures a yoke 29 to the carri-age cross beam 25a. The lower ends of the yoke 29 have secured thereto an axle housing 30 in Fig. 2 for supporting the pair of wheels 27 having tires thereon. Surrounding the pivot bolt 28 in Figs. 4, 5 and 6 are spaced apart side retaining plates 31, 31 welded or otherwise secured to the carriage cross beam 25a and a central tongue member 32 welded or otherwise secured to the yoke 29. This structure permits only limited arcuate swing of each pair of wheels 27 around the approximately vertically extending pivot bolt 28, as shown in Figs. 4 and 5, since tongue member 32 can only pivot until it engages one or the other of the side retaining, plates 31, 31. The whole carriage 25v cannot swivel about a vertical axis. This limited pivot construction of each pair of wheels 27 is necessary for the following reasons. First, if both pairs of wheels 27, 27 were toed in when the dolly rst engages the ground, the forward movement of the scraper would tend to toe them in still farther against each other so that side drag or scung of the scraper dolly tires would result. Second, if wheelv carriage 25 were permitted to swing about a 360 vertical pivot with respect to post 22, the laterally outermost tires would probably strike the front of apron 16 in view of theglimited clearance between the parts, as shown in Fig. l.

The operation and advantages of the scraper dolly should he readily apparent. Not only does the dolly solve the highway load limit problem in many States by `supporting a portion of the scraper weight to reduce the load on the front and rear scraper wheels, but also the dolly cooperates with the conventional scraper parts for giving a oating action for following an uneven or rough roadY surface while continuing to support its share of the scraper weight and for making the assembly and disassembly of the dolly to `theV scraper an easy task.

ln the formjust described, the dolly 2i clamps directly to the lift beam 14a `at the front end of the scraper bowl 14. Installing the dolly is a very simple procedure since it is merely necessary to raise the scraper bowl 14 in the usual manner by the :conventional hydraulic hoist means for raising the scraper bowl until the howl is just high' enough to slip the dolly in place, as shown in Figs. 2' and 3, before tightening the clamp bolt 23. The bowl then can. be lowered until its weight rests on the scraper dolly 21. The scraper bowl 14 is lowered byy merely contracting the length of the hydraulic hoist means 18 by means of the conventional hydraulic fluid control. Then, the forward part of the scraper bowlA i4 is secured to the scraper dolly 21 so that the total empty scraper weight is divided over more axles and wheels or tires contacting the road surface. As the scraper travels along the highway, the bowl can float up and down if the dolly 21 encounters uneven or rough road surfaces so that the dolly can readily follow the road surface while supporting its portion-of the scraper weight.

The vertical float of bowl 14 and dolly 21 is obtained -by two different structural features inthe scraper construction. First, the lost motion connection between the hydraulic hoist means 18 and the scraper bowl 14 for permitting 11p-float of the scraper bowl during digging. This lost motion means may take the form of the flexible cable 19 in Fig. 1 or inthe aforementioned U. S. patent 4application Ser. No; 111,496, now Patent No. 2,674,815, take the ferm' of 'die'elongatedI slot in the lifting link in the aforementioned U. S. patent application No. 287,- 772, or may take the form of some other suitable lost motion connection. Any of these lost motion connections mentioned permit limited vertical oat either up or down, to the scraper bowl 14 and the dolly 21 to suit minor road surface variations without any m-ovement of the scraper lift hoist 18. Second, additional vertical float is obtained by hydraulic iiuid freely flowing into and out of the hydraulic hoist means 18. 'l'he conventional scraper has a pressure iiuid supply through the hydraulic hoist means 18 with means for controlling the iiow `from said supply thereto. This control means can be moved to one position for expanding the hydraulic hoist means 18 and raising the scraper bowl, to another position for preventing the uid from entering or leaving the hydraulic hoist means for maintaining the bowl at a given height, and to another position for contracting the length of the hy- `draulic hoist means 18 for lowering the scraper bowl and for permitting the hydraulic iiuid to freely iiow into or out of the ihydraulic h-oist means `18 in response to the pull exerted on the iexible cable 19 or on the slotted lift link by -the bowl weight. When the scraper dolly 21 is lbeing used, the control should be left in the last mentioned position for vertical oat. If it is left in one of the other positions, the downward pull on the cable 19 or on the slotted lift link may be resisted by the resistance to compression of the fixed volume of hydraulic fluid in the cylinder. An upward push on the slotted lift link may be resisted by a vacuum pull in the opposite direction caused by an attempt to expand the hydraulic fluid there- When the scraper travels around a corner, the Idolly wheels 27 can Iturn a certain amount due to the caster elfect of the mountings shown in Figs. 4, and 6. Howover, when being manuevered in confined quarters, the bowl can be lifted slightly by expanding the hydraulic hoist means 18 so that the dolly 21 is elevated and does not touch the ground which makes it unnecessary to slide the -dolly sideways to cause seul-ling of Ithe tires. Also, the hydraulic hoist means 18 can lift the dolly 21 completely oh' the road surface when `the scraper is being transported over a high crowned railroad track which might normally cause -either the front or rear scraper wheels 12 and 13 to be lifted olf of Ithe roadway if dolly 21 could not be lifted.

Also, the hydraulic means 18 can lbe expanded to lift Ithe scraper bowl 14 and dolly 21 off the road surface when a destination is reached so that the weight is removed from the dolly to make its disassembly from the bowl an easy task.

Fig. 7 discloses a rnodiiied form of dolly wherein the wheel Vcarriage 25 is pivotally supported with respect to post 22 `on a Vertical axis for 360 pivot or full caster. The two pairs `of wheels 27, 27 and their supporting yokes 29, 29 can either be secured to the carriage cross beam 25a, or `it may have a partial pivot with respect thereto as shown in Figs. 4, 5 and 6. In this construction, Ithe post 22 is made in two sections with bearing surface plates 35 attached to the upper section and 36 attached to the lower section, with an approximately vertically extending pivot pin 37 connecting the two plates together and permitting full caster lor 360 pivot. However, with this construction if clearance is needed the front apron 16 may be raised to a partially open position by its elevating hydraulic hoist means and carried in this partially open position Ito allow ysufficient room for the full caster type scraper dolly to make a full 360 pivot withou-t interference therewith.

It should :be readily apparent that the scraper dolly 21 or a modiiication thereof can be readily secured to other parts of the scraper to give ythe oating, lifting, and Weight dividing action heretofore mentioned. The dolly 21 could be secured to other parts of the scraper bowl to take advantage of lthe iioating action; but having it secured to the front of the bowl, where bowl movement is the greatest, gives the. -best results. 'This location is near wheels 12,

which carry the greatest load, and the dolly when so located will most effectively take the load olf wheels 12. Also, since fthe pull yoke 17, pivotally secured to the bowl 14 at pivot 17a, moves up and down with the scraper bowl 14, the dolly 41 (shown in Fig. 8 and similar to dolly 21) could be detachably secured to the pull yoke between the front and rear scraper wheels 12 and 13. If desired, `the dolly 41 could be secured back near the pivot 17a for greater vertical movement and a more sensitive mounting. However, this latter position will be farther away from the scraper wheels 12 supporting the greatest weight. The dolly 41 would not rem-ove as much weight from the scraper wheels 12 in this position as it would if it were mounted farther forward.

Some scraper bowls do not have a lift beam 14a in which case the scraper dolly lcould take the form shown in Fig. 9. Here, the dolly 21 in lFig. 2 is divided into two parts 43, 43 with a separate part 43 removably secured to one of each of the opposite side Walls 14b of scraper bowl 14 and with each part having a pair of `dual wheels 27.

It should now be apparent that the floating acti-on of the scraper dolly, enabling it to follow uneven or rough road surfaces while continually supporting its portion of the scraper weight to reduce the 4load on the front and rear scraper wheels, is obtained by 'the articulate construction of the scraper. This articulate construction causes the eifective transfer of part of the weight to the dolly even though the road surface traversed is uneven. The articulate construction can take the .form shown in the present disclosure wherein the pull yoke 17 is pivotally secured to the scraper bowl 14 by pivot 17a, or it may take the form of a rigid frame between the front and rear scraper wheels 12 and 13 with only the scraper bowl being movable vertically with respect thereto. 1n this latter form, the scraper dolly could be secured to the scraper bowl with some of the advantages mentioned heretofore including 4the floating, lifting and weight sharing action. [t should be clearly understood that the invention disclosed herein in a scraper dolly can be -used not only in the digging and carrying scraper structures disclosed herein but also in :other scraper structure as Well.

Vari-ous changes in details and arrangement of parts can be made by one skilled in the art without departing from the spirit of this invention or the scope of the appended claims.

What I claim is:

l. A digging and carrying scraper comprising a scraper bowl member having wheels supporting its rear end, a yoke member pivotally connected on a transverse pivotal axis adjacent its rear end to said bowl member and having its front end adapted for attachment to supporting wheels, a bowl member raising means mounted on said yoke member and lhaving a lost motion connection with said bowl member for permitting bowl vertical oat, said bowl member being movable between a lower digging position and a higher carrying position by raising or lowering said bowl member and a yoke rnember, a dolly detachably secured to one of said members between said wheels and movable with said bowl member and yoke member from a ground engaging position to said higher carrying position, said dolly normally resting on the ground in an intermediate position for supporting a portion of the scraper weight to reduce `the load on said front and rear Wheels, said dolly being utilized only when the ydigging and carrying scraper is in transport.

2. A digging and carrying scraper comprising supporting wheels at its front and rear ends, a scraper bowl supported between said wheels and having a digging blade at its lower edge, means for raising said bowl between a lower digging position and a higher carrying position and having a lost motion connection with said bowl for permitting bowl vertical float, and a detachable dolly to be secured to the scraper bowl between said front and rear wheels for supporting a portion of the scraper weight when said bowl is in an intermediate posltion to reduce the load on said front and rear wheels, said oowl vertical iloat permitting said dolly to move vertically out of an even-level position with said wheels when bumps are encountered, said dolly being utilized only when the digging and carrying scraper is in transport.

3. A digging and carrying scraper comprising a scraper bowl member having wheels supporting its rear end, a yoke member pivotally connected adjacent its rear end to said bowl member and having its front end adapted for attachment to supporting wheels, means mounted on said yoke member for raising said bowl member between a lower digging position and a higher carrying position, said bowl member raising means having a lost motion connection with said bowl member for permitting bowl vertical float, a dolly detachably secured to one of said members between said wheels and movable with said bowl and yoke members from a ground engaging position to said higher carrying position, said dolly normally resting on the ground in an intermediate position for supporting a portion of the scraper weight to reduce the load on said front and rear wheels, said bowl member up-float permitting said dolly to move vertically out of an in-line-position with said wheels when bumps are encountered, said dolly being utilized only when the digging and carrying scraper is in transport.

4. In combination, a tractor having rear drive wheels, a digging and carrying scraper comprising a scraper bowl member having wheels supporting its rear end, a pull yoke member pivotally connected adjacent its rear end to said bowl and having its front end pivotally .secured to said tractor adjacent said drive wheels, a bowl member raising means mounted on said yoke member and having a lost motion connection with said bowl member for permitting bowl vertical oat, said bowl being movable between a lower digging position and a higher carrying position by raising or lowering said bowl and yoke, a dolly detachably secured to one of said members between said wheels and movable with said bowl and yoke members from a ground engaging position to said higher carrying position, said dolly normally resting on the ground in an intermediate load-carrying position for supporting a portion of the scraper weight to reduce the Aload on said iront and rear wheels, said dolly being utilized only when the digging and carrying scraper is in transport.

5. A digging and carrying scraper usable alternatively in either scraping operation or transport, compri-sing supporting wheels at its front and rear ends, a scraper bowl being supported between said wheels and having a digging blade at its lower edge for use in the scraping operation, means for raising said bowl between a lower digging position and a higher carrying position, said mean-s having a lost motion connection with said bowl member for permitting bowl vertical oat, and a dolly detachably secured during transport to the bowl between said front and rear wheels when said bowl is in an intermediate position for supporting a portion of the scraper weight during transport to reduce the load on said front and rear wheels, whereby said raising means will permit said dolly to raise above the normal surface of the road when a high bump is encountered during transport or can be used to raise said bowl when said dolly is to be' assembled or disassembled on said bowl.

6. A digging and carrying scraper comprising a scraper bowl member having wheels supporting its rear end, a yoke member pivotally connected adjacent its rear end to said bowl member and having its front end adapted for attachment to supporting wheels, means mounted on said yoke member for raising said bowl member between a lower digging position andY a higher carryingv position, said means having a lost motion conrieciiou with sai-d bowl member for permitting bowl vertical float, a dolly detachably secured to one of said members between said wheels and movable with said bowl member and yoke member from a ground engaging position to said higher carrying position, said dolly normally resting onthe ground in an intermediate position for' supporting a portion of the scraper weight` to reduce the load on said front and rear wheels, whereby said raising me ns will permit said dolly to raise above the normal surface of the road when a high bump is encountered or can be used `to raise said members when said dolly is to be assembled or disassembled on said one member, 'd dolly being utilized only when the digging and carrying scraper is in transport.

7. A digging and carrying scraper comprising supporting wheels at its front and rear ends, a scraper bowl being supported between said wheels and having a digging blade at its lower edge, hydraulic hoist means for raising said bowl between a' lower digging position and a higher carrying position, a dolly detachably secured to the bowl between said front and rear wheels and engaging the ground when said bowl is in an intermediate position for supporting a portion of the scraper weight to reduce the load on said front and rear wheels, means for controlling the ow into said hydraulic hoist means and having a control position wherein hydraulic iluid will freely flow into or out of said hydraulic hoist means for permitting up-oat and down-lloat of said bowl and dolly when bumps are encountered on the road surface, whereby said raising means will permit said dolly to raise above the normal surface of the road when a high bump is encountered or can be used to raise said bowl when said dolly is to be assembled or disassembled on said bowl,` said dolly being utilized only when the digging and carrying scraper is in transport.

8. A digging and carrying scraper comprising a scraper bowl member having wheel-s supporting its rear end, a yoke member pivotally connected adjacent its rear end to said bowl member and having its front end adapted for attachment to supporting wheels, hydraulic hoist means mounted on said yoke for raising said bowl member between a lower digging position and a higher carrying position, a dolly detachably secured to one of said members between said wheels and movable with said bowl member and yoke member from a ground engaging position to said higher carrying position, said dolly normally resting on the ground in an intermediate position for supporting a portion of the scraper weight to reduce the load on said front and rear wheels, a pressure lluid supply for `said hoist means, means for controlling the iiow from said supply into said hydraulic hoist means and having a control position wherein hydraulic iluidv will freely tlow into or out of said hydraulic hoist means for uptloat and down-float of said bowl and yoke members when bumps are encountered on the road surface, whereby said raising means will permit said dolly to rise above the normal surface of the road when a high bump is encountered or can be used to raise said members when said dolly is tobe assembled or disassembled on said one member, said dolly being utilized yonly when the digging and carrying scraper is in transport.

9. A digging and carrying scraper comprising `supporting wheels at its front and rear ends, a scraper bowl, a. bowl raising means having a lost motion connection with said bowl for permitting bowl vertical float, and a dolly detachably secured to the scraper bowl between said front and rear wheels for supporting a portion of the scraper weight to reduce the load on said front and rear wheels, said dolly compris-ing a supporting pos-t, `a removable connection at the top of said post for attachment to a lift beam of said scraper bowl, a wheeled carriage pivotally attached to the lower edge of said post about a horizontal axis, two pairs of wheels with each pair pivotally mounted for arcuate movement about a vertical axis on opposite sides of said carriage, said dolly being utilized only when the digging and carryingis'craper is in transport.

10. A digging and carrying `scraper comprising a scraper bowl member having wheels supporting its rear end, a yoke member pivotally connected adjacent its rear end to said bowl member and having its front end adapted for attachment to support-ing wheels, a bowl member raising means mounted on said yoke member and having a lost motion connection with said bowl member for permitting bowl vertical float, said bowl member being movable between a lower digging position and a higher carrying position by raising or lowering said bowl member and yoke member, a dolly de-tachably secured to one of said members between said Wheels and movable with said bowl member and yoke member from a ground engaging position to said higher carrying position, said dolly con prising a supporting post, a removable connection at the top of said post for attachment to said one member, a Wheeled carriage pivotally attached to the lower edge of said post about a horizontal axis, two pairs of wheels with each pair pivotally mounted for limited movement about a vertical axis on opposite sides of said carriage, said dolly normally resting on the ground in an intermediate position for supporting a portion of the scraper weight to reduce the load on said front and reaa wheels, said dolly being utilized only when -the digging and carrying scraper is in transport.

11. A vehicle, comprising a body member having wheels supporting its rear end, a yoke member pivotally connected adjacent its rear end to said body member and having its front end adapted for attachment to supporting wheels, means mounted on said yoke member for raising said body member between a lower position `and a higher position, said body member raising means having a lost motion connection with said body member for permitting complete freedom of vertical iloat, a dolly detachably secured to one of `said members between said wheels and movable with said members from a ground engaging position to said higher position, sa'id dolly normally resting on the ground in an intermediate position `for supporting a portion of the vehicle weight to reduce the load on said front and rear wheels, said body member upfloat permitting said dolly to move vertically out of an `in-line position with said wheels when bumps are encountered, said dolly being utilized only when said vehicle is in transport.

12. A Vehicle, comprising a body member having wheels supporting its rear end, a yoke member pivotally connected adjacent its rear end to said body member and having its front end adapted for attachment to supporting wheels, hydraulic hoist means for rai-sing said body member between a lower position and a higher position, a dolly detachably secured to one of said members between said wheels and movable with said members from a ground engaging position to said higher position, said dolly normally resting on the ground in an intermediate position for supporting Ka portion of the vehicle weight to reduce the load on said front and rear wheels, a pressure fluid supply for said hoist means, means for controlling the ow from said supply into said hydraulic hoist means and having a control position wherein hydraulic iluid will freely flow into or out of said hydraulic hoist means for up-oat and doWn-oat of said members when bumps are encountered on the road sur-face, whereby said raising means will permit said dolly to raise above the normal surface of the road when a highl bump is encountered or can be used to raise said members when lsaid dolly is to be assembled or disassembled on said one member, said dolly being utilized only when said vehicle is in transport.

13. A vehicle, comprising a body member having wheels `supporting its rear end, a yoke member pivotally connected adjacent its rear end to said body member and having its front end adapted for attachment to supporting wheels, a body member raising means mounted on said yoke member and having a lost motion connection with said body member for permitting vertical oat, said body member being movable between a lower position and a higher position by raising or lowering said members, a dolly detachably secured to one of `said members between said Wheels and movable with said members from a ground engaging position to said higher position, said dolly comprising a supporting post, a removable connection at the top of said post lfor attachment to said one member, a wheeled carriage pivotally attached to the lower edge of said post about a horizontal axis, twov pairs of wheels with each pair pivotally mounted for limited movement about a vertical axis on opposite sides of said carriage, said dolly normally resting on the ground in an intermediate position for supporting a portion of the vehicle weight to reduce the load on said front and rear wheels, said dolly 4being utilized only when said vehicle is in transport.

14. In the combination set forth in claim 11, wherein said lost motion conection is a flexible cable permitting up-oat.

15. A digging and carrying scraper as dened by claim 1 wherein said dolly comprises a wheel having a castor mounting `for a 360 swing around an approximately Vertical pivot with respect to said scraper.

16. A digging and carrying scraper as defined by claim 2 wherein said dolly includes at least one pair of laterally spaced wheels and a castor mounting connected to said wheels for providing a 360 swing around an approxi mately vertical pivot with respect to said scraper.

References Cited in the le of this patent UNITED STATES PATENTS 1,293,536 Pfeil Feb. 14, 1919 1,412,940 Hart Apr. 18, 1922 2,107,118 Knapp Feb. 1, 1938 2,110,186 Weimer Mar. 8, 1938 2,116,412 Reid May 3, 1938 2,228,534 Reid Ian. 14, 1941 2,271,304 Mulholland Ian. 27, 1942 2,309,766 Harroun et al Feb. 2, 1943 2,382,449 Simmons Aug. 14, 1945 2,445,134 Curell July 13, 1948 2,585,117 Gurries Feb. 12, 1952 2,621,939 Le Tourneau Dec. 16, 1952 2,639,159 Milligan et al. May 19, 1953 2,662,781 Hopson Dec. 15, 1953 2,674,815 Adams Apr. 13, 1954 FOREIGN PATENTS 476,828 Canada Sept. 1l, 1951

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