WO2002031272A1 - Scraper bowl with a moveable cutting edge - Google Patents

Abstract

A scraper bowl for attachment to the frame (16) of an earth scraper (10) is disclosed. The scraper bowl (20) includes a pair of spaced apart side walls (22A, 22B), with each of the side walls being adapted for pivotable attachment to the scraper frame, a back wall (24), and a floor (26). The floor includes a fixed section (28) and a moveable section (30), with the moveable section including a forward edge (31) defining a cutting blade (32). Accordingly, the sidewalls, the back wall and the floor cooperate to contain material scraped from a support surface as the scraper bowl proceeds along a path.

Description

SCRAPER BOWL WITH A MOVEABLE CUTTING EDGE

Cross-Reference to Related Applications

This application claims the priority benefit of U.S. Provisional Application

No. 60/239,625 filed October 10, 2000, the entire disclosure of which is

incorporated herein by reference.

Field of Invention

The present invention relates generally to earth scrapers incorporating scraper bowls, and more particularly to a scraper bowl having a moveable cutting

blade.

Background of the Invention

Earth scrapers are devices for the cutting, loading, transporting, discharging,

and spreading of earth. An earth scraper is typically a tractor drawn apparatus having a scraper bowl which scrapes earth material from the ground and temporarily stores it for transport and later discharge. The scraper bowl is typically a box or

bowl shaped structure having an open top, and includes a floor having a cutting

blade at its front edge.

Typically, the scraper bowl is pivotally mounted to a frame, such as the

frame of the towing tractor, so that, as the bowl pivots about the frame, the cutting

blade can be brought into position to penetrate the ground. The cutting blade

scrapes earth material from the ground as the device is drawn along, thus loading

the scraped earth material into the bowl.

Earth scrapers may be constructed as stand-alone units having a towing tongue such that the scraper is towable behind a tractor. Alternatively, scrapers

may be constructed as part of motorized, self-driven vehicles that have been

designed especially for scraping operations. For such motorized scrapers, the

scraper bowl is pivotally attached to the frame of the vehicle between the front and

rear axles of the vehicle. On stand-alone scrapers, the scraper is pivotally mounted

to a draft frame having a wheeled axle, with the draft frame being attachable to a

tractor.

To cut and load earth material into the scraper bowl, the scraper bowl is rotated or pivoted so that the cutting edge forms an angle with the ground. The

angle will depend on the desired depth of the cut. As the scraper bowl is moved

forward over the ground, the cutting blade penetrates the earth, thus cutting the

ground such that the forward movement of the device loads the cut earth material into the bowl. An apron at the front edge of the bowl is partially closed so as to

provide a gap between a bottom edge of the apron and the cutting blade to allow the cut earth material to enter the bowl, and to retain the material that has accumulated

in the scraper bowl.

When the bowl must be unloaded, the apron opens and an ejector plate moves forward, thus pushing the earth material out of the scraper bowl. By

controlling the rates at which the ejector plate and the scraper vehicle move

forward, an operator can control the spreading of the earth material as it discharges

from the scraper bowl.

The draft force required to move the cutting edge through the ground

increases as material accumulates into the bowl. A standing wave or surcharge of disturbed earth material builds up in front of the cutting edge, and the required draft

force increases further as new material enters the bowl. If the draft force exceeds

that available to the scraper bowl, the cutting edge must be raised to reduce the

depth of cut. Also, the cutting forces have vertical components that act downward

until some fifty to sixty percent of the material payload is loaded into the bowl. The

vertical components act ahead of the pivot and provide a moment at the rear axle,

therefore limiting the useful traction of the rear wheels.

Accordingly, an improved scraper bowl would be desirable.

Brief Description of the Drawings

Fig. 1 is a side elevational view of a self-driven earth scraper incorporating a

scraper bowl;

Fig. 2 is a front isometric view of a scraper bowl assembled in accordance

with the teachings of the present invention and which is adapted for use with the earth scraper of Fig . 1 ;

Fig. 3 is a rear isometric view of the scraper bowl illustrated in Fig. 2;

Fig. 4 is a side elevational view of the scraper bowl illustrated in Figs. 2 and

3; and

Fig. 5 is a side elevational view similar to Fig. 4 but illustrating a section of

the floor in a rearward position.

Description of the Preferred Embodiment

The example described herein is not intended to be exhaustive or to limit the scope of the invention to the precise form or forms disclosed. Rather, the following exemplary embodiment has been chosen and described in order to best explain the

principles of the invention and to enable others skilled in the art to follow the

teachings thereof.

Referring now to the drawings, an earth scraper of the type commonly

employed in the art is shown in Fig. 1 and is generally referred to by the reference

numeral 10. The earth scraper 10 may be a self-driven motorized scraping

apparatus that is used for scraping earth material from the ground for storage and later discharge. It will be understood that the teachings of the present invention are

equally applicable to stand-alone scraping units that are drawn by a towing vehicle,

such as a tractor. However, for the sake of simplicity, only the self-driven earth

scraper 10 will be discussed herein. The earth scraper 10 includes front wheels 12

and rear wheels 14 attached to a frame 16. The earth scraper 10 also includes an engine (not shown) and a drive system (not shown), both of which may be

conventional, and which enable the earth scraper 10 to proceed along a path over

the ground 18.

Referring to Figs. 2-4, a scraper bowl assembled in accordance with the teachings of the present invention is generally referred to by the reference numeral

20. The scraper bowl 20 includes a pair of side walls 22a and 22b. Each of the

side walls 22a, 22b is attachable to the scraper frame 16 in a manner well known to

those skilled in the art, such that the scraper bowl 20 is pivotable with respect to the

scraper frame 16. Conventional actuators (not shown) and controls (not shown)

may be employed for controlling the pivoting action of the scraper bowl 20 relative to the frame 16.

The scraper bowl 20 also includes a back wall 24 and a floor 26. The floor

26 includes a fixed section 28 and a moveable section 30, with the moveable section

30 including a forward edge 31 having a cutting blade 32. The pair of side walls

22a, 22b, the back wall 24, and the floor 26 cooperate to hold the material that is

scraped as the scraper moves along a path.

As shown in Fig. 4, the moveable section 30 includes a plurality of rollers

34, with the rollers 34 engaging one or more tracks 36 defined in the sidewalls 22a, 22b, so that the moveable section 30 is moveable between a rearward position and a

forward position. The rollers 34 and the tracks 36 may be supplied by any one of a

suitable manufacturers of heavy equipment components. An example of suitable

components may be obtained from Pacific Bearing Company and sold under the

HENI RAIL^® name.

One or more conventional actuators 38 (shown schematically in Figs. 4 and 5) engages the moveable section 30, thus enabling the moveable section 30 to move

back and forth along the tracks 36 supported by the rollers 34. The actuator 38 may be a hydraulic actuator of the type commonly employed in the art. Alternatively,

the actuator 38 may comprise a rack and pinion type system (not shown) or other

gear-based system (not shown). It will be understood that the moveable section 30

may be moved to any position between the rearward position (Fig. 5) and the

forward position (Fig. 4). As the moveable section 30 moves toward the forward

position, the moveable section 30 moves substantially out from under the fixed

section 28, thus extending or closing the floor 26. As outlined above, the moveable section 30 defines a section of the floor 26, and thus when the moveable section 30

is in the rearward position, the floor 26 is partially open, with at least a portion of

the moveable section 30 being disposed generally under the fixed section 28.

The scraper bowl 20 may include an ejector plate 40. If provided, the

ejector plate 40 is preferably disposed at the rear section of the scraper bowl 20.

The ejector plate 40 may be moveable between an initial position (disposed

generally rearward) and a discharge position (disposed generally forward and

indicated in phantom in Fig. 5).

The ejector plate 40 is operatively mounted to pair of upper ejector tracks

42a and 42b, which are generally disposed along the sidewalls 22a and 22b,

respectively (shown in Figs. 2 and 4). The ejector plate 40 further is mounted to a pair of lower ejector tracks 44a, 44b, which are generally disposed along the

sidewalls 22a and 22b, respectively (shown in Fig. 4). The tracks 42a, 42b, 44a,

and 44b guide the ejector plate 40 between the initial position (rearward) and the discharge (forward) position. Preferably, the ejector plate 40 engages the upper

ejector tracks 42a, 42b and the lower ejector tracks 44a, 44b with a plurality of

rollers, which include a lower set of rollers 46 (shown in Fig. 4) and an upper set of rollers 48 (shown in Fig. 4). The rollers 46, 48 and their associated tracks 42a,

42b, 44a, 44b, may be constructed of readily available heavy equipment components

of the type commonly employed in the art. An ejector actuator 50 engages the

ejector plate 40 to move the ejector plate 40 between the initial position (rearward)

position and the discharge (forward) position. The actuator 50 may be a hydraulic

actuator, or, alternatively, a rack and pinion or other gear-based actuating system. The scraper bowl 20 further includes an apron 52 mounted adjacent the front

portion of each of the side walls 22a, 22b. The apron 52, which may be

conventional, spans the distance between the side walls 22a, 22b and is moveable

between a first position and a second position. A gap defined between the apron 52

and the floor 26 changes as the apron 52 moves between the first position and the

-second position. The scraper bowl 20 also includes side cutting blades 54, which

are positioned at the front edge of the side walls 22a, 22b.

In operation, as will be explained in greater detail below, the scraper bowl

20 is rotated about a draft frame pivot 56 to bring the cutting blade 32 to an angled

position relative to the ground. As is known, the angle of this position is adjustable using conventional controls and actuators. As the scraper 10 proceeds along a

desired path, the cutting blade 32 engages the ground below the surface of the

ground, thus cutting the earth material in the path of the scraper 10. As the scraper

10 proceeds along the path, the material is forced into the scraper bowl 20. As the scraper 10 continues, freshly cut material forces the previously cut material up the

cutting blade 32 and into the scraper bowl 20.

As outlined above, the scraper bowl 20 is pivotable relative to the frame 16 of the scraper 10. Thus, the scraper bowl may be rotated back (e.g., the scraper

bowl may be rotated counter-clockwise when viewing Figs. 4 or 5) about the draft

frame pivot 56 when either the scraper bowl 20 is filled with material, or when the

desired amount of material is scraped from the path. This rotation thus lifts the

cutting blade 32 upwardly and out of the ground. The material in the scraper bowl

20 then may be transported to a discharge location (not shown) and discharged from the scraper bowl 20.

In accordance with the disclosed example, the moveable section 30 is

initially positioned under the floor 26 and behind the draft frame pivot 56. At its

initial position as illustrated in Fig. 5, the cutting blade 32 is either aligned with or

positioned forward of a forward edge 29 of the fixed section 28. As shown in Figs.

2-5, the fixed section 28 includes an inclined surface 58 at its forward edge 29 that

acts as a ramp to load earth material onto the fixed section 28. The front of the

scraper bowl 20 is then lowered by rotating the scraper bowl 20 about the draft

frame pivot 56 (in a clockwise direction when viewing Figs. 4 and 5), such that when the scraper 10 moves along the path, the cutting blade 42 penetrates the

surface of the ground at a desired cutting depth. Once the position and angle of the

cutting blade 32 are set, the scraper 10 proceeds forward along the path, thus

engaging and cutting into the earth as outlined above such as the earth material is

cut and loaded into the scraper bowl 20. In at least one possible mode of operation, the operator of the scraper bowl

20 controls the speed of the scraper 10, the angle of rotation of the scraper bowl 20 (i.e., the depth of cut), and the position of the cutting blade 32. The operator can also control the rate of advance or withdrawal of the cutting blade 32 and the rate of

rotation of the scraper bowl 20. The operator selects the depth of cut, which can

vary depending on soil and ground conditions. The operator typically sets the depth

of cut based on experience, knowing that depending on soil and ground conditions,

a cut that is too deep will slow down the scraper 10 and may even cause a total

stoppage as wheel traction falls below the force necessary to move the scraper 10 forward to cut the ground (i.e. , wheel spin may result). If wheel spin occurs, the

operator can raise the scraper bowl 20 or withdraw the cutting blade 32, or both.

As the scraper 10 moves forward, the freshly cut material pushes the

previously cut material up onto the moveable section 32, and further onto the fixed

floor 26 by pushing the previously cut material up the inclined surface 58. Initially,

as the rear wheels of the scraper move forward onto the freshly cut surface (i.e. the

rear wheels will be positioned lower than the front wheels). The operator may have

to adjust the depth of cut by stopping the scraper 10, and, for example, move the moveable section 32 rearward, adjust the angle of rotation of the scraper bowl 20,

and then resume moving the scraper 10 forward to resume cutting.

Because the moveable section 30 is initially under the fixed section 28, the

earth material tends to accumulate first on the fixed section 28. Stated another way, with the moveable section 30 disposed in or toward the rearward position of Fig. 5,

the earth material tends to accumulate more readily toward the back of the scraper

bowl rather than toward the front of the scraper bowl.

As the scraper 10 continues to move forward and more material is loaded

into the scraper bowl 20, the moveable section 30 may gradually be moved forwardly toward the forward position. The moveable section 30 may also be

moved forwardly toward the forward position in stages as the scraper bowl 20 fills

from the rear to the front. For example, the operator can fill the section of the

scraper bowl 20 that is above the fixed section 28 first, and then move the moveable

section 30 forward either gradually or in stages to fill the forward section of the

scraper bowl 20. Should the scraper 10 continue to proceed along the path, eventually the moveable section will reach the forward extent of its allowable travel.

When the scraper bowl 20 is filled or the scraping stops for some other reason, the

scraper bowl 20 may be rotated about the draft frame pivot 56 toward its pre-

scraping position. The material may then be transported to a discharge location.

The actual loading rate would depend on a number of variables, including,

for example, the actual physical dimensions of the scraper bowl, the type, density

and/or moisture content of the earth material, the speed of the scraper 10, the angle of the scraper bowl 20 relative to the frame 16, and the position of the apron. A

skilled and experienced operator of conventional scrapers would readily be able to

attain and control a desired loading rate, and would readily be able to determine the best position of the moveable section 30 as well as the best angle for the scraper

bowl 20.

Typically, the material in the scraper bowl 20 is either unloaded at a certain

location, or controllably spread over a desired area. To unload the material, the moveable section 30 may be moved rearwardly, such that the moveable section 30 is

gradually moved under the fixed section 28. As this happens, a gap or opening is gradually formed in the floor 26 as the moveable section 30 and its attached cutting

blade 32 move rearwardly away from the forward extent of the scraper bowl 20.

Material in the scraper bowl 20 is free to fall through the gap, thus unloading the

forward portion of the scraper bowl 20.

To unload the material that is held in the rear section of the scraper bowl 20,

the ejector plate 40 may be moved forwardly to push material toward the forward

section of the scraper bowl 20. The scraper bowl 20 may further be unloaded by simultaneous backward movement of the moveable section 30 and forward

movement of the ejector plate 40.

The rate by which material is unloaded from the scraper bowl 20 or spread

in a certain area can be controlled by the rates of forward movement of the ejector

plate 40, backward movement of the moveable section 30, and forward (or

rearward) travel of the scraper- 10. For example, to unload the material without any

controlled spreading, the moveable section 30 may be moved to its most rearward

position, while simultaneously moving the ejector plate 40 to its most forward

position. Alternatively, in order to spread the loaded material in a desired area in a

more controlled manner, the moveable section 30 may be moved back to a

predetermined position that yields a desired material unloading rate through the gap

opened between the cutting blade 32 and the forward extent of the scraper bowl 20.

With controlled gradual forward movement of the ejector plate 40, loaded material falls through the gap at a desired rate. The speed of the scraper 10 as it travels in a

desired spreading area during controlled unloading, controls the rate by which material is spread^" in that area. The material can also be unloaded by moving the apron 52 to open the front section of the scraper bowl, while simultaneously moving

the ejector plate 40 forward to push the material out from the front of the scraper

bowl 20.

The material can further be unloaded by simultaneously moving the apron 52

to open the front section of the scraper bowl, and moving the moveable section 30

backward to open a very large gap between the cutting blade 32 and the apron 52. This unloading method of using rearward movement of the moveable section 30

combined with movement of the apron 52 may be used when uncontrolled or

relatively rapid dumping of the material in a certain location is desired. The actual

unloading rate would depend on a number of variables, including, for example, the

actual physical dimensions of the scraper bowl, the type, density and/or moisture

content of the earth material, the speed of the scraper 10, the angle of the scraper

bowl 20 relative to the frame 16, and the position of the apron 52. Again, a skilled

and experienced operator of conventional scrapers would readily be able to attain

and control a desired unloading rate and would readily be able to determine the best

position of the moveable section 30 and the best position of the apron 52.

In the disclosed example, it will be appreciated that the scraper bowl 10 may

reduce the forces required to cut and load earth material into the scraper bowl 20,

and will give more control over such forces to the operator of the scraper 10. As

the scraper bowl 20 is rotated so as to lower the cutting blade 32, the cutting blade 32 moves under the ground surface, loading disturbed earth material into the scraper

bowl 20. To avoid the buildup of a surcharge of disturbed earth material in front of the cutting blade 32, the moveable section 30 may be moved progressively forward, which according to the disclosed example may offer certain operational advantages.

These advantages may include, by way of example rather than limitation, may be

explained as follows. The progressive forward movement of the cutting blade 32 as

the scraper bowl 20 is loaded may substantially reduce the downward force on the

cutting blade 32, because a buildup of earth material in front of or on top of the

cutting blade 32 is lessened or eliminated. Second, the material loaded into the scraper bowl is initially loaded into the rearward portion of the scraper bowl 20.

The rear loading of the scraper bowl 20 of the present invention reduces the

downward forces on the cutting blade 32 because of a reduction in build-up of

collected earth material behind the cutting blade 32. The rear loading of the scraper

bowl 20 does not create a clockwise moment about the draft frame pivot 56 (when

viewing Fig. 4), and thus the traction of the rear tires 14 of the scraper 10 is not

reduced. Instead, the rear loading of the scraper bowl 20 creates a downward force behind the draft frame pivot 56, thus creating a moment (counter-clockwise in Fig.

4) about the draft frame pivot 56, which increases traction of the rear tires 14 of the scraper 10. Third, the material inside the scraper bowl 20 can be unloaded without

opening the apron 52. After the scraper bowl 20 is loaded, the backward movement

of the moveable section 30 opens a gap between the cutting blade 32 and the front

edge of the scraper bowl 20. The collected material in the scraper bowl falls through the gap as the ejector plate 40 moves forward to push more material onto

the gap, thus eliminating the need, in certain circumstances, for opening the apron

52.

Those skilled in the art will appreciate that, although the teachings of the invention have been illustrated in connection with certain embodiments, there is no

intent to limit the invention to the disclosed example. Instead, the intention of this

application is to cover all modifications and embodiments fairly falling within the

scope of the appended claims either literally or under the doctrine of equivalents.

Claims

Claims

1. A scraper bowl for use with a scraper having a frame, the scraper

bowl comprising:

a pair of spaced apart side walls, each of the side walls being adapted

for pivotable attachment to the scraper frame; . . - - a back- wall; and -

a floor, the floor including a fixed section and a moveable section,

the moveable section including a forward edge defining a cutting blade; whereby the sidewalls, the back wall and the floor cooperate to

contain material scraped from a support surface as the scraper bowl proceeds along

a path.

2. The scraper bowl of claim 1 , including a plurality of rollers

operatively engaging the sidewalls and the moveable section, the plurality of rollers being arranged to permit the moveable to move between a rearward position in

which the moveable section is disposed generally below the fixed section and a forward position in which the forward edge of the moveable section is disposed forwardly of the fixed section.

3. The scraper bowl of claim 2, including an actuator engaging the

moveable section for moving the moveable section between the rearward position

and the forward position.

4. The scraper bowl of claim 1, wherein the moveable section is

shiftably mounted to a track defined in part by the pair of side walls.

5. The scraper bowl of claim 1, including an ejector plate, the ejector

plate being moveable relative to the sidewalls between an initial position and a

discharge position.

6. The scraper bowl of claim 5, including a plurality of ejector tracks

defined in part by the pair of side walls for guiding the ejector plate between the

initial position and the discharge position.

7. The scraper bowl of claim 6, wherein the plurality of ejector tracks

include an upper ejector track defined in part by an upper section of the pair of

sidewalls.

8. The scraper bowl of claim 6, wherein the plurality of ejector tracks include a lower ejector track defined in part by a lower section of the pair of

sidewalls.

9. The scraper bowl of claim 5, wherein the ejector plate includes a

plurality of rollers, at least some of the plurality of rollers slidably engaging the pair

of side walls.

10. The scraper bowl of claim 9, wherein the plurality of rollers includes

an upper set of rollers slidably engaging an upper section of the pair of side walls.

11. The scraper bowl of claim 9, wherein the plurality of rollers includes

a lower set of rollers slidably engaging a lower section of the pair of side walls.

12. The scraper bowl of claim 5, including an ejector actuator for moving

the ejector plate.

13. The scraper bowl of claim 1, wherein each of the pair of sidewalls includes a front portion, and including an apron mounted adjacent the front portion

of each of the pair of sidewalls and spanning the distance therebetween, the apron

being moveable between a first position and a second position to thereby change the

size of a gap defined between the apron and the floor.

14. The scraper bowl of claim 13, including an ejector plate extending between the pair of sidewalls and being moveable between an initial position and a discharge position, the ejector plate and the apron cooperating to unload material

from the scraper bowl.

15. The scraper bowl of claim 1 , wherein each of the pair of sidewalls

includes a front edge, and wherein at least a portion of the front edge of each of the

sidewalls includes a side cutting blade.

16. The scraper bowl of claim 1, including an ejector plate extending

between the pair of sidewalls and being moveable between an initial position and a

discharge position, the ejector plate and the moveable section cooperating to unload

material from the scraper bowl.

17. A scraper bowl for use in a scraper having a frame, the scraper bowl

comprising:

a pair of spaced apart side walls, each of the side walls being adapted for pivotable attachment to the scraper frame;

a fixed floor;

a moveable floor, the moveable floor being mounted for sliding

movement between a rearward position in which the moveable floor is disposed

generally below the fixed floor and a forward position in which a front edge of the moveable floor is spaced forwardly of the fixed floor, the forward edge including a

cutting blade; a moveable ejector blade, the ejector blade being moveable relative to the sidewalls and the fixed floor along a generally horizontal path between an initial position and a discharge position;

an apron mounted adjacent a front portion of each of the pair of

sidewalls and spanning the distance therebetween, the apron being moveable

between a first position and a second position to thereby change the size of a gap

defined between the apron and the floor.

18. A scraper for scraping material from a support surface as the scraper

proceeds along a path, the scraper comprising: a frame;

a scraper bowl having a forward portion and a rearward portion, the

scraper bowl being pivotally mounted to the frame and including a pair of spaced

apart side walls, a back wall, and a floor; and

means engaging a portion of the floor for loading the material into a

rearward portion of the scraper bowl prior to loading the material into a forward

portion of the scraper bowl as the scraper proceeds along the path.

19. The scraper of claim 18, wherein the scraper bowl is pivotally

mounted to the frame by a central pivot, the rearward portion being disposed behind

the central pivot and the forward portion being disposed in front of the central pivot.

20. The scraper of claim 18, wherein each of the sidewalls includes a

pivot, and wherein the rearward portion is disposed behind the pivots and the

forward portion is disposed in front of the pivots.

21. A scraper for scraping material from a support surface as the scraper

proceeds along a path, the scraper comprising:

a frame;

a scraper bowl having a forward portion and a rearward portion, the

scraper bowl being pivotally mounted to the frame and including a pair of spaced

apart side walls, a back wall, and a floor; and the floor including a fixed section and a moveable section, wherein

the moveable section operates to load material into a rearward portion of the scraper

bowl prior to loading the material into a forward portion of the scraper bowl as the

scraper proceeds along the path.