US3660914A - Lift and lock structure for scraper blade assembly - Google Patents

Abstract

An earthmoving scraper of the type having a bowl assembly including a cutting edge fixed on the forward end thereof, the bowl assembly being defined by a pair of side walls, an ejector forming a rear wall, and a bowl floor rearwardly of the cutting edge, the bowl floor being slidable to a rearward position relative to the side walls to expose a material ejection opening. To facilitate control of the depth of spread or fill during material unloading, a strike-off blade is pivotally supported on the slidable floor, the strike-off blade being adapted to be pivoted to a lower, operational position when the floor is moved to a rearward or unloading position. Cam and stop means operatively associated with the strike-off blade and the side walls, are provided for moving the strike-off blade to an upper position when the floor is in a forward position wherein the strike-off blade forms a load-supporting extension of the floor. In this environment, the present invention provides lock means for locking the strike-off blade in the upper position thereby circumventing accidental loss of payload as might be occasioned by undesired downward pivotal movement of the strike-off blade caused by the payload weight thereon, or by shock loads.

Description

United States Patent Bechman et al.

[54] LIFT AND LOCK STRUCTURE FOR SCRAPER BLADE ASSEMBLY [72] Inventors: William H. Bechman, Amherst, N.Y.; Walter E. Lott, Washington; John F. Slewert, Peoria, both of ill.

[73] Assignee: Westinghouse Air Brake Company, Peoria,

ill.

[22] Filed: Sept. 15, 1970 [21] Appl.No.: 72,505

Related US. Application Data [63] Continuation of Ser. No. 869,946, Oct. 27, I969, abandoned, which is a continuation of Ser. No. 684,103, Nov. 20, 1967, abandoned.

[52] U.S.Cl ..37/129,37/l26AC [51] Int. Cl... ..E02l3/62 [58] FieldofSearch ..37/l29, 126,8, 118, 124

[56] References Cited UNITED STATES PATENTS 2,278,036 3/1942 Bird ....37/l26 2,988,832 6/l96l Hancock et al..... ....37/l29 3,274,7ll. 9/1966 Johnson etal...... ....37/l29 3,292,279 12/1966 Rockwell et al. ..37/l29 1 May 9, 1972 Attorney-Wolfe, Hubbard, Leydig, Voit &-Osann, Ltd.

[ ABSTRACT An earthmoving scraper of the type having a bowl assembly including a cutting edge fixed on the forward end thereof, the bowl assembly being defined by a pair of side walls, an ejector forming a rear wall, and a bowl floor rearwardly of the cutting edge, the bowl floor being slidable to a rearward position relative to the side walls to expose a material ejection opening. To facilitate control of the depth of spread or fill during mate rial unloading, a strike-off blade is pivotally supported on the slidable floor, the strike-off blade being adapted to be pivoted to a lower, operational position when the floor is moved to a rearward or unloading position. Cam and stop means operatively associated with the strike-off blade and the side walls, are provided for moving the strike-off blade to an upper position when the floor is in a forward position wherein the strikeofi' blade forms a load-supporting extension of the floor. In this environment, the present invention provides lock means for locking the strike-off blade in the upper position thereby circumventing accidental loss of payload as might be occasioned by undesired downward pivotal movement of the strike-off blade caused by the payload weight thereon, or by shock loads.

6 Claims, 4 Drawing Figures P'A'TE'N'TEDMAY 9 I972 SHEET 1 [IF 3 INVENTORS WILLIAM H. BECHMAN WALTER E. LOTT JOHN F. SIEWERT JOHN F. SCHMIDT ATTORNEY CROSS REFERENCES TO RELATED APPLICATIONS This application is a continuation of U.S. Pat. application Ser. No. 869,946 filed Oct. 27, 1969 which, in turn, was a continuation of U.S. Pat. application Ser. No. 684,103 filed Nov. 20, 1967, both of which are now abandoned.

FIELD OF INVENTION The invention relates to earthmoving scrapers, and more particularly, to such scrapers equipped with slidable floors to which strike-off blades are pivotally connected.

SUMMARY OF THE PRIOR ART In recent years, earthmoving scrapers of the elevating type, such as disclosed in U.S. Pat. No. 2,988,832 to Hancock et al., have enjoyed substantial commercial acceptance. Such scrapers include an elevating conveyor positioned in the forward end of a scraper bowl to aid in moving excavated material upward and rearward in the bowl. To facilitate unloading of such materials, in spite of the presence of the elevating conveyor that partially blocks the forward end of the bowl, such scrapers often include a slidable floor to the rear of a fixed cutting edge, the slidable floor being adapted to be retracted by any suitable means, such as hydraulic jacks, to expose an opening for ejection of material effected by forward move- -ment of an ejector or tailgate. Because material is ejected re'arwardly of the fixed cutting edge, this scraper design makes desirable the provision of a strike-off blade to level or control the depth of spread or fill of ejected materials. Such strike-off blades are usually pivotally connected to the slidable floor in a manner disclosed in the above-identified patent. As is disclosed therein, the strike-off blade may include cam means to pivot the strike-off blade from a lower, operative position wherein it depends vertically to a point substantially below the slidable floor section, to an upper, horizontally disposed position wherein the strike-off blade forms a load-supporting extension of the slidable floor. Although such arrangements are generally satisfactory, it has been found that, in practice, the means for holding the floor in a forward position, and the strike-off blade in an upper position, sometimes yields (in a hydraulic system, such yielding occurs because of leaks). Because of such yielding and the design of the previously mentioned cam means, the weight of the payload or shocks imposed upon the strike-off blade means may cause the strike-off blade to move to a lower position exposing the material ejection opening and thereby causing a loss of payload and other operational disadvantages.

SUMMARY OF THE INVENTION It is a general object of the present invention to provide a scraper including a slidable floor and a strike-ofi' blade assembly which circumvents or minimizes the problems heretofore noted.

In achieving this general object, the present invention provides an earthmoving scraper of the type having a bowl assembly including a cutting edge fixed on the forward end thereof, a pair of side walls, a rear wall extending between the side wall, and a bowl floor rearward of the cutting edge and supported on the side walls, the floor being movable by power means from a forward position to a rearward position to expose an opening for ejecting material. A strike-off blade is pivotally supported on the floor, the strike-off blade being adapted to be pivoted to a lower operational position when the floor is moved to a rearward position. Additionally, positioning means operatively associated with the strike-off blade is provided for moving the strike-off blade to an upper position when the floor is in a forward position. To circumvent accidental ejection of material, the present invention eliminates any tendency for the weight of the payload to cause the floor to move towardsits rearward position or the strike-off blade to pivot to its lower position by providing lock means for positively locking the strikeoff blade in the upper position.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation view of an earthmoving scraper including a slidable floor and a strike otf blade according to the present invention.

FIG. 2 is a side elevation view on a much larger scale than FIG. 1, and showing only that portion of the scraper which incorporates the positive locking cam-and-stop mechanism with immediately associated structure.

FIG. 3 is a partial view,being a front elevation of substantially the structure shown in FIG. 2 but on a somewhat larger scale and with the cutting edge omitted for easier understanding of the movable strike-off blade assembly; and

FIG. 4 shows the strike-off blade assembly in the open position.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT Referring in more detail to the drawings, an earthmoving scraper shown therein comprises a conventional wheeled tractor 10 having an engine 11, tractor 10 adapted to be pivotally connected to a scraper bowl unit 12 for steering movement therebetween. Reference may be had to U.S. Pat. No. 3,338,329, issued Aug. 29, 1967 to Edward G. Orth, for a disclosure of the steering means. Bowl unit I2 includes a gooseneck and draft frame assembly 13, the rear end of which is pivotally connected to a bowl assembly 14 of a generally conventional type. Any suitable motor means, such as hydraulic jack assemblies 15, connect these latter elements for elevational adjustment of the bowl assembly 14. An auxiliary engine 16 may if desired be positioned at the rear of the bowl as' sembly 14 for driving scraper wheels 17. Bowl assembly 14 includes a pair of laterally spaced, vertically extending side walls 18 between which a vertically extending ejector or tailgate 20 is positioned. Means (not shown) are provided to reciprocate the ejector. A cutting edge 24 is fixedly positioned at the forward end of the side walls 18 above which an elevator assembly 25 is positioned to aid in moving material into the bowl assembly.

The bowl assembly 14 further comprises a horizontally extending floor 26 extending between the side walls 18, the floor 26 including a rearward, fixed floor section 28 and a forward, movable or slidable floor section 30 supported at its lateral ends on the side walls 18 by roller assemblies 32. Each roller assembly 32 comprises vertically extending, front and rear plates34 and 36, respectively, positioned outwardly of the side walls 18. On the inner face of the plates 34 and 36, rollers 38 are rotatably mounted in pairs for cooperation with a track 40 provided along the outer face of the side walls 18.

To position the slidable floor section 30, a hydraulic jack unit is provided at each side of the scraper, one such unit being shown at 42. Each such unit 42 comprises a piston rod assembly 44, the longitudinal ends of which extend through apertures in brackets 46 fixed to the side walls 18. The ends of the rod assembly 44 are threaded and receive threaded nuts 48. The rod assembly 44 includes a piston 50 on an intermediate portion thereof and a pair of forward and rearward extending passages 52 and 54 are provided, the passages extending through opposite ends on the rod assembly 44 for directing hydraulic fluid to or from opposite sides of the piston 50. Passages 52 and 54 are in communication with suitable fluid conduits, such as conduit 56 shown in FIG. 2, and piston 50 cooperates with a cylinder assembly 58 to form first and second chambers 60 and 62 for receiving fluid from the conduits.

Cylinder assembly 58 includes rear and front cover and seal assemblies 63 and 64 respectively, the rear cover and sea] assembly 63 including a downward extending lug 66, the lower end of which is loosely received in a slot provided in the upper end of the rear roller plate 36. Many details not shown here because they are incidental to this invention may be seen by referring to the copending application (now abandoned) of Walter E. Lott, Ser. No. 684,102, filed Nov. 20, 1967 and assigned to the assignee of this invention, and which discloses and claims many features not claimed and not fillly shown here.

To facilitate leveling or controlling the depth of spread or fill of the material ejected, a strike-off blade assembly 90 is provided. Assembly 90 includes a transversely extending strike-off blade frame 92 coextensive with, and pivotally connected to, the forward end of the slidable floor section 30 by a hinge. Specifically, in the embodiment shown, a plurality of spaced ears are provided on frame 92. One such ear is shown at 94. The ears are perforated to receive a hinge pin 96, which passes through the ears and also through a plurality of pipe lengths 98. Pipe lengths 98 extend between ears 94 and are themselves secured to the forward face of movable floor 30 in any suitable manner as by weldments 100. Ears 94, pipe lengths 98, and pin 96 thus form a hinge of a type commonly referred to as a piano hinge," having a pivot axis I-I-I-I.

Positioned on the lower forward face of the strike-off blade frame is a strike-off blade edge 102 which may comprise a plurality of replaceable cutting edge lengths. The strike-off blade assembly further comprises a cam plate 104 on either lateral end of the strike-E blade frame 92, cam plates 104 being outboard of bowl side walls 18. Roller stops 106, which cooperate with cam plates 104 in a manner discussed more fully hereinafter, are provided on the outboard faces of the bowl side walls 18.

Each of cam plates 104 comprises a generally J-shaped plate including a relatively large longer leg 108 integral with a relatively smaller short leg 110. A slot 112 is provided in the forward face of each cam plate 104 between the legs 108 and 110. The upper and shorter leg 110 includes a forward portion 114 for a purpose to be subsequently discussed. When the strike-off blade is in its uppermost position, as shown in FIG. 2, roller stop 106 is received and bottomed in the slot 112. It should be noted that the pivot axis l-I-I-I of the strike-off blade assembly hinge is to the rear of and below the transverse pivot axis of the roller stop 106 so that the weight of the payload on the strike-off blade assembly 90 urges the same from a horizontal position toward a lower operational position. However, such movement is prevented by the engagement of the upper legs 110 with the upper surface of the roller stops 106 that results from the bias applied to the cam plates 104 by the weight of the payload acting thereon through the pivot axis I-IH of the strike-off blade assembly 90. In this manner, a positive lock is provided prohibiting downward movement of the strike-off blade assembly except after the slidable floor section 30 has been moved rearwardly a predetermined distance determined by the length of the legs 110, and a self-energizing locking effect is present in spite of any leakage which may exist in the slidable floor hydraulic jack units 42. This aspect of the present invention is particularly beneficial in view of the prior art practices wherein, upon the occurrence of leakage in the slidable floor operating jacks, shock loads occurring during high speed travel and the weight of the payload on the strike-off blade sometimes caused minor movements of the slidable floor section which, in turn, caused the strike-off blade to pivot to a lower position thereby permitting a substantial loss of payload and an undesirable deposition of the same on the haulroad or the like. This undesirable condition is avoided in the present invention by provision of a positive strike-off blade lock, the locking force of which is generated by the gravity load on the blade assembly 90.

Upon retraction or rearward movement of the slidable floor section 30 a predetermined distance from the position shown in FIG. 2, as for material ejection or unloading, the cam plates 104 are disengaged from the roller stops 106 and the strike-off blade assembly 90 is permitted to fall by gravity to a position shown in FIG. 4 to an extent limited by engagement of the rear of the strike-off blade assembly 90 with a stop 1 l6 fixed on the lower face of the slidable floor section 30.

To protect the jack unit 42 from dirt, rocks, etc., a cover 1 18 (FIG. 2) is desirably secured between nuts 48.

OPERATION To retract the slidable floor section 30 to expose an opening through which material may be ejected by forward movement of the ejector 20, fluid is directed to the rear chamber of the floor operating jack assemblies; specifically, to chamber 62 of the jack assembly shown in FIG. 2. The cylinder assembly 58 is thereby moved in a rearward direction along the rod assembly 44 and, by virtue of the engagement of the lug 66 with the aforesaid slot in the rear roller plate 36, the slidable floor section 30 is likewise moved to the rear. To close the material ejection opening by moving the floor section 30 to a forward position, as shown in FIG. 2, wherein the forward end thereof abuts the supporting structure of cutting edge 24, fluid is directed to the forward chamber 60 of jack assembly 42.

As soon as the cam plates no longer engage their respective rollers (upon retraction), the weight of the load rotates the strikeoff blade assembly clockwise as seen in FIG. 2 to the operating position shown in FIG. 4 wherein blade assembly engages stop 116. In this operational position, the strike-off blade assembly serves to level or control the depth of spread of materials ejected during the scraper unloading operation.

After unloading, the slidable floor section 30 may be moved in a forwardly direction to close the ejection opening and raise the strike-ofi' blade assembly to the position shown in FIG. 2. The latter operation is accomplished as follows. After substantial forward movement of the floor section 30, the forward face of each upper leg of the cam plates 104 contacts its roller stop 106. Further forward movement causes each cam plate 104 to rotate upward in a counterclockwise direction, seating the roller stop 106 in its slot 112 of the cam plate 104.

Because the weight of strike-off blade assembly 90, and the load on it, is carried by roller stops 106, actual contact is at or near the top of the roller. When the jacks 42 exert their full force on assembly 90 in the closed position, the center of the contact area is shifted slightly to the left of top center as seen in FIG. 2. This results in a thin crescent-shaped gap between the roller and the slot at the left and bottom thereof, as can be seen in FIG. 2.

Such rotation of the cam plates 104 pivots the entire strikeoff blade assembly 90 upward until the edge 102 thereof contacts or is close to the lower face of the supporting structure of the scraper cutting edge 24 and the strike-off blade assembly is positioned in a generally horizontal position wherein it forms a payload-carrying bridge between the slidable floor section 30 and the cutting edge 24 and its supporting structure. The language or is close to" in the foregoing sentence is used because, in a preferred embodiment, nuts 48 are so adjusted that piston 50 bottoms in cylinder 58 when element 102 lacks about one-eighth inch of contacting the underside of the supporting structure for blade 24.

It will be noted from FIGS. 2 and 3 that the portion 114 of short leg 110 underhangs somewhat the topmost portion of roller 106. This feature provides additional locking against unwanted rearward movement of the movable floor 30.

We claim as our invention:

1. In an earthmoving scraper having a bowl with a movable floor section for relatively discharging a payload via an opening through the bottom of the bowl, and a strike-off blade assembly pivotally mounted on said floor section; an improved lift and lock mechanism for said strike-off blade assembly comprising a cam and an aligned roller, one mounted on said bowl and the other mounted on said strike-off blade assembly for engagement as said floor section moves in a direction to close said opening; said cam having a camming surface leading to a recess, with said camming surface configured to cooperate with said roller as said floor moves in said direction to first urge said strike-off blade assembly upwardly against the force of gravity and to then permit said strike-off blade assembly to settle downwardly thereby seating said roller in said recess so that said strike-off blade assembly is then releasably but positively locked in an upper position in which it forms a payload carrying bridge across an otherwise uncovered portion of said opening.

2. The improvement of claim 1 wherein said cam is mounted on said strike-off blade assembly, and said roller is mounted on a fixed portion of said bowl.

3. The improvement of claim 2 wherein said roller has a transversely extending central axis, and said strike-off blade assembly is pivotable relative to said movable floor section about an axis offset to the rear and below said central axis, whereby the weight of said material acting on said strike-off blade assembly when the same is in said upper position urges said cam to return said roller seated within said recess.

4. The improvement of claim 1 wherein said cam includes upper and lower legs having said recess defined therebetween, said upper leg having a free edge with a lip which extends below at least a portion of roller when the same is seated within said recess, whereby said lip aids in preventing accidental release of said strike-off blade assembly from its upper position.

5. The improvement of claim 4 wherein said cam is mounted on said strike'off blade assembly for pivotal movement therewith, said roller is mounted on a fixed portion of said bowl has a transversely extending central axis, and said strike-off blade assembly is pivotable relative to said movable floor section about an axis offset to the rear and below said central axis, whereby the weight of the payload acting on said strike-off blade assembly when the same is in said upper position urges said cam to retain said roller within said recess.

6. The improvement of claim 5 wherein said bowl further includes a cutting edge, and the payload carrying bridge provided by said strike-off blade assembly when it is in said upper position is between said floor and said cutting edge.

I 1 i i I

Claims (6)

1. In an earthmoving scraper having a bowl with a movable floor section for relatively discharging a payload via an opening through the bottom of the bowl, and a strike-off blade assembly pivotally mounted on said floor section; an improved lift and lock mechanism for said strike-off blade assembly comprising a cam and an aligned roller, one mounted on said bowl and the other mounted on said strike-off blade assembly for engagement as said floor section moves in a direction to close said opening; said cam having a camming surface leading to a recess, with said camming surface configured to cooperate with said roller as said floor moves in said direction to first urge said strike-off blade assembly upwardly against the force of gravity and to then permit said strike-off blade assembly to settle downwardly thereby seating said roller in said recess so that said strike-off blade assembly is then releasably but positively locked in an upper position in which it forms a payload carrying bridge across an otherwise uncovered portion of said opening.

2. The improvement of claim 1 wherein said cam is mounted on said strike-off blade assembly, and said roller is mounted on a fixed portion of said bowl.

3. The improvement of claim 2 wherein said roller has a transversely extending central axis, and said strike-off blade assembly is pivotable relative to said movable floor section about an axis offset to the rear and below said central axis, whereby the weight of said material acting on said strike-off blade assembly when the same is in said upper position urges said cam to return said roller seated within said recess.

4. The improvement of claim 1 wherein said cam includes upper and lower legs having said recess defined therebetween, said upper leg having a free edge with a lip which extends below at least a portion of roller when the same is seated within said recess, whereby said lip aids in preventing accidental release of said strike-off blade assembly from its upper position.

5. The improvement of claim 4 wherein said cam is mounted on said strike-off blade assembly for pivotal movement therewith, said roller is mounted on a fixed portion of said bowl has a transversely extending central axis, and said strike-off blade assembly is pivotable relative to said movable floor section about an axis offset to the rear and below said central axis, whereby the weight of the payload acting on said strike-off blade assembly when the same is in said upper position Urges said cam to retain said roller within said recess.

6. The improvement of claim 5 wherein said bowl further includes a cutting edge, and the payload carrying bridge provided by said strike-off blade assembly when it is in said upper position is between said floor and said cutting edge.

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