US3905136A

US3905136A - Ground supported elevator in elevating type scraper

Info

Publication number: US3905136A
Application number: US519056A
Authority: US
Inventors: John H Hyler
Original assignee: Westinghouse Air Brake Co
Current assignee: Komatsu America International Co
Priority date: 1974-10-30
Filing date: 1974-10-30
Publication date: 1975-09-16
Anticipated expiration: 1992-09-16

Abstract

An elevating type scraper for earth moving purposes having an open-fronted bowl with rear supporting wheels and with a scraper blade at the front of the bowl. The bowl is pivotally supported on a pair of draft members forming part of the tractor supported draft frame. A bowl supporting actuator is interposed between the draft frame and the front end of the bowl to determine the degree of tilt of the bowl hence the depth of cut of the blade. An elevator of the endless conveyor type is positioned at the front end of the bowl having its lower end in proximity to the blade and inclined upwardly and rearwardly so that the earth loosened by the blade is conveyed into the bowl. The elevator is mounted on the bowl for forward and upward swinging movement with respect to the ground. Ground engaging shoes connected to the elevator side frame members engage the undisturbed ground surface slightly ahead of the elevator for supporting the elevator at a running level relative to the ground surface in which the envelope of the elevator flight is maintained at a sweeping height above the ground. The shoes are mounted on levers pivoted to the elevator frame, and means are provided, in the form of a torque tube extending between the levers, for insuring that the shoes are at all times adjusted in the same phase position to maintain the same sweeping height. For positioning the shoes an actuator is interposed between at least one of the shoes and the elevator frame. In an alternate embodiment the shoes are coupled hydraulically for positioning and adjustment in unison.

Description

United States Patent 1 Hyler [451 Sept. 16, 1975 GROUND SUPPORTED ELEVATOR IN ELEVATING TYPE SCRAPER John H. Hyler, Peoria, 111.

[73] Assignee: Westinghouse Air Brake Company,

Pittsburgh, Pa.

[22] Filed: Oct. 30, 1974 [21] Appl. No.: 519,056

[75] Inventor:

Primary Examiner-Stephen C. Pellegrino Attorney, Agent, or Firm-Wolfe, Hubbard, Leydig, Voit & Osann, Ltd.

[5 7 ABSTRACT An elevating type scraper for earth moving purposes having an open-fronted bowl with rear supporting wheels and with a scraper blade at the front of the bowl. The bowl is pivotally supported on a pair of draft members forming part of the tractor supported draft frame. A bowl supporting actuator is interposed between the draft frame and the front end of the bowl to determine the degree of tilt of the bowl hence the depth of cut of the blade. An elevator of the endless conveyor type is positioned at the front end of the bowl having its lower end in proximity to the blade and inclined upwardly and rearwardly so that the earth loosened by the blade is conveyed into the bowl. The elevator is mounted on the bowl for forward and upward swinging movement with respect to the ground. Ground engaging shoes connected to the elevator side frame members engage the undisturbed ground surface slightly ahead of the elevator for supporting the elevator at a running level relative to the ground surface in which the envelope of the elevator flight is maintained at a sweeping height above the ground. The shoes are mounted on levers pivoted to the elevator frame, and means are provided, in the form of a torque tube extending between the levers, for insuring that the shoes are at all times adjusted in the same phase position to maintain the same sweeping height. For positioning the shoes an actuator is interposed between at least one of the shoes and the elevator frame. In an alternate embodiment the shoes are coupled hydraulically for positioning and adjustment in unison.

5 Claims, 6 Drawing Figures PATENTED 3 905 1% saw 1 [1F 2 g m x-4'1 s SE? ms sum 2 of 2 GROUND SUPPORTED ELEVATOR IN ELEVATING TYPE SCRAPER BACKGROUND OF THE INVENTION The invention relates generally to an earth-moving device in the form of a tractor-drawn scraper having a blade for loosening the soil and an elevator for convey: ing the loosened soil into the scraper bowl, and which has improved means for maintaining the elevator in predetermined grazing relation with respect to the ground regardless of the depth of cut.

In conventional elevating type scrapers, the elevator is swingably mounted to the scraper bowl, with its normal running position being determined by a setof stops. The stops are adjustable so as to provide theproper relationship between the conveyor and the undisturbed ground ahead of the blade for an assumed depth of cut. However, the problem is that the depth of cut, which is under the control of the machine operator, can be varied over a rather wide limit. When the blade is lowered to take a deeper cut, the elevator is correspondingly lowered, following the blade, so that the flights instead of sweeping over the surface of the undisturbed ground, strike the surface with some violence. Conversely, when the blade is adjusted to a higher cutting level, the elevatortends to be lifted clear of the ground thereby reducing the efficiency of the loading operation and affecting load retention.

Where the elevator rides too low, the shocks to the elevator structure and its driving system, particularly where the ground is hard, may be so severe as to be of destructive effect. As each flight strikes the ground, the elevator in effect tries to climb up upon the flight, resulting in a high peak loading, loss of power and the setting up of severe vibration which reduces the life of the whole scraper assembly to say nothing of the annoyance and fatigueto the operator.

This condition has been so consistently encountered in the past that compromises have been incorporated into the design and operation of the elevator, such as driving the elevator at reduced speed and the use of additional, more closely spaced flights, both of which have meant a sacrifice in loading efficiency. Moreover, where the elevator rides too high or too low, loosened soil piles up ahead of the blade, and must be pushed by the blade, so that greater horsepower is required to get the job done.

In order to make the elevator less sensitive to variations in depth of cut, the tendency is to limit the scraper to wide shallow cuts which, in turn, limits the range of soils that can be handled effectively. i

In an effort to establish a more optimum elevator porisk of overloading or damaging the elevator or its- .but which, because of the spacing between the wheels and the elevator, is not capable of detecting abrupt changes in ground level occurring right at the bottom of the elevator. Moreover, addition of compensatory adjusting systems for automatic elevator height control,

' often with servo systems, tends to add complication sition for a given depth of cut, it has been a common necessary elevator adjustment.

Moreover, conventional means for adjusting elevator height cannot cope with extraordinary conditions such as the encountering of a window, bo ulders or other obstructions and the driver tends to rely upon a selfelevating feature, that is, the ability of the elevator flights to climb up upon an obstruction, even at the and expense, both in first cost and in the continued maintenance which is required.

SUMMARY OF THE INVENTION It is, accordingly, an object of the present invention to provide an elevator height control arrangement for a scraper in which the elevator maintains itself in a predetermined sweeping relationship with the undisturbed ground in front of the blade regardless of variations in blade cutting depth. In practicing the present invention, the elevator rides upon a pair of ground engaging shoes which are adjustably secured to the elevator frame and which support the elevator at a constant running level relative to the ground in which the flights are maintained at an optimum sweeping height, the shoes beingcoupled together and having a common adjusting means so that the shoes are at-all times positioned simultaneously in the same phase position.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1v is a side elevation of a complete elevating scraper assembly, including tractor, to which the present invention has been applied.

FIG. 2 is a fragmentary, somewhat diagrammatic, side view of an elevator including its longitudinal frame and showing the flights in the desired sweeping clearance relationship with respect to the level of the undisturbed ground.

FIG. 3 is a diagrammatic front view corresponding to FIG. 2. i 2

FIG. 4 shows a simplified hydraulic circuit for controlling the actuator used in FIGS. 2 and 3.

FIG. 5 is a front view corresponding to FIG.3 but showing a modified form of the present invention.

FIG. 6 is an hydraulic diagram corresponding to the modification of FIG. 5. i

While the invention has been described in connection with certain preferred embodiments, it .will be understood that there is no intention to limit the invention to such embodiments and it is intended, on the contrary, to cover the various alternative and equivalent constructions included within the spirit and scope of the appended claims.

DETAILED DESCRIPTION OF THE FIRST ENIBODIMENT rigid construction pivoted to the tractor at 15 for horizontal swinging movement and carrying a transversely extending torque tube 16 to which draft members 17 are secured. The latter extend rearwardly and downwardly and arepivoted at 18 to the respective sides of the bowl. The rear end of the bowl is supported upon a pair of wheels 19. t 3

'Mounted along the front edge of the bowl is ablade 20 which digs into the ground to a depth determined by the angle of tilt'of the bowl about the draft axis 18.For determining this angle, and the cutting depth, a bowl supporting actuator 21 is provided at each side of the bowl,'the actuator shown in FIG. 1 having an'upper point of anchoring 22 to the tractor draft frame and having a lower connection 23 to the front portion of the bowl structure," conveniently" one of the bowl side plates. v

For the purpose'of conveying soil' loosened by the blade to the back of the bowl, an elevator 30 is provided having ,a lower end which rides above and slightly ahead of the blade 20 and which extends rearwardly and backwardly, in effect enclosing the front end of the bo wl The elevator includes a pair of

longitudinal frame rnembers

31, 32 journalling a cross shaft 33 driving a pair

bf sprocket wheels

34, 35. At the bottom end of the elevator, in aligned positions, are

idler wheels

36, 37. Trained about the sprockets and idlers are con- ,Veyor,

chains

41, 42 having transversely extending flights/l3, only one of which'h'as been shown in FIG. 2 having an envelope 45. The drive shaft'33 is driven'by a motor 46 viaia gear box 47. i

The blade moving through the ground tends tob'reak the soil clear along a shear plane indicated at 50. The

elevator is mounted so that its low point with respect to the undisturbed ground surface51 approximately coincideswith the end 52 of the shear, plane. The elevator should be sufficiently elevated above the ground I under running conditions as to provide a slight amount of grazing clearance 53 which may, for example, be on -the order of an inch or somewhat greater than an' inch. Forthe purpose of mounting the elevator for upward I and forward swingingmovement, thereby to change the .positionof the elevator with respect to the ground, and

i are mounted uponthe bowl structure in the downward path of swing of the elevator frame members and with "shims being adjustably interposed. However, in accordance with the present invention, the elevator is di- *'rectlysupported. upon a pair of adjustable interconnecte'd ground engaging shoes which engage the undisturbed ground-surface slightly ahead of the elevator for supporting the elevator at a running level which insures that the flights will have a predetermined sweeping clearance. Thus, referring to FIG. 2, a ground engaging shoe 60 is provided secured to a mount in the form of a centrally pivoted lever having a rearwardly extending portion =61 and a forwardly extending portion 62.cen-

trally pivoted-at 63 to a bracket 64 at thelowerend of the frame'member'31. The ground engaging shoe 60 presents an arcuately curved surface with sufficient width so as to serve as a runner supporting the elevator in running position and bearing the weight of the eleva- Incarrying out the invention, a similar ground engaging shoe l-is provided at the other side of the elevator structure (FIG. 3) having a mount which includes a rearwardly extending portion 71, a forwardly extending portion 72, and which is pivoted at 73 to the companion elevator frame member 32 upon a bracket 74.

In order to insure that the shoes 60, 70 are atall times in the-same phase position, the forward ends 62, 72 of the mounts are rigidly interconnected by a torque tube 80. While the torque tube is forwardly offset from the

fulcrum axis

63, 73, so that it clears the flight envelope 45, it effectively rigidities the shoes with respect to one another. For the purpose of adjusting shoe position, an actuator 90 (FIG. 4) is interposed between the shoe and the adjacent elevator frame member 31. The actuator has a first end 91 pinned to the elevator frame and a second end 92 pinned to the shoe mount. For controlling actuator 90 a valve 94, connected to a source of pressure and a sump S, is movable between a neutral position in which the actuator 90 is blocked against movement and extreme positions in which the actuator is moved in opposite directions for adjustment purposes. Because of the torque tube 80, shoe stays precisely in step. I

The actuator is initially adjusted to provide the desired, limited amount of ground clearance 53 (FIG. 2). Subsequently, when the operator either increases or decreases the level of cut of the blade 20, the elevator now being directly ground supported, is completely unaffected by this adjustment and continues to ride at the same level of ground clearance. In the event that a windrow or other obstruction is encountered, the shoes 60, 70 simply rideup upon it, raising the elevator frame sufficiently so as to avoid any condition of impact between theflights and the undisturbed ground.

Theautomatic adjustment of clearance that this provides is foolproof and inexpensive since it avoids the expense and complication of elevation compensating schemes or servo systems both of which tend to be afflicted with serviceproblems.

, Manual control of the shoe actuator 90, in addition to.v establishing normal running clearance, can be utilized in addition by the operator to secure temporary increased clearance to accommodate boulders or other obstructions which may be encountered.

It will'be apparent to one skilled in the art that the torque tube, that is, torque transmitting element 80,

I need not be offset forwardly from the fulcrum of the shoe mount and that the element may be coaxial with the fulcrum provided that the supporting brackets 64 are sufficiently extended in the forward direction to provide the necessary clearance of the flight envelope.

tor without sinking appreciably into the surface of the ground. t

DESCRIPTION OF SECOND EMBODIMENT DETAILED .6,

separate actuators

95, 96 of double ended construction are interposed between the shoes and the

respective frame members

31, 32. The actuators, as shown in FIG. 6, are of the type having

piston rods

97, 98 which extend in opposite directions all the way through the outer cylinder to provide equal fluid displacement in both directions of movement, the piston rods being sealed at the respective ends of the cylinder. The

actuators

95, 96 are connected in series with one another as shown under the joint control of a slide valve 99. With the valve in its neutral position, fluid is trapped in the actuators, locking them in the same phase position. In the event that it is necessary to raise the elevator to increase running clearance, which requires that the actuators be contracted, the control valve 99 is moved to the left so that fluid flows into the righthand side of the actuator 95 causing it to contract, and with an equal amount of fluid flowing to the righthand side of actuator 96 causing it to control the same amount. When the desired displacement of the actuators is achieved, the valve is restored to its neutral position blocking off any further flow and locking the shoes in position until such time as the valve may be readjusted. When it is desired, eventually, to make up for any leakage, fluid may be added by tapping in upon the line 100 which interconnects the actuators via a simple plug or check valve connection.

While the shoes 60, 70 are preferably in the form of curved skid surfaces, it will be apparent that the term shoe is not limited thereto and the curved surfaces thereof could, if desired, be in the form of wheels or rollers without departing from the invention.

The above discussion has been directed toward elevator support under operating conditions. During transport the bowl is elevated by the cylinders 21 to cause relative approach of the elevator to the bowl. Such approach is preferably limited by limit stops 101, 102 (FIG. 2), on elevator and bowl respectively, which serve to lift the elevator clear of the ground when the bowl is raised.

One advantage of the above construction is that pounding at the conventionally provided stops is eliminated. Thus no energy absorbing means need be provided at the stops. It is found that the hydraulic actuator and its connected control system provides sufficient damping and energy absorption. If additional damped resiliency is required, the actuator 90 may be of the double-ended type and shunted by an automatic centering-type bypass device 105, including opposed preloaded springs, with a restricted orifice 106 in series therewith. Or, if desired, the hydraulic system can be used in a checked float made by shunting the actuator 90 by a check valve 107, faced as shown, in series with a manual enabling valve 108. Such mode of operation may be desirable upon encountering a narrow windrow extending along the path of movement of the scraper and which is so narrow as to engage the flights but not one of the shoes. In such event the flight will initially climb upon the obstruction, raising the elevator frame relative to the shoes, accompanied by collapsing movement of the actuator, so that fluid is bypassed around the actuator to hold the shoes in extended supporting relation until manual valve 94 is moved to restore the shoes to normal position. This insures that after the initial climbing of the elevator flights the elevator frame will be shoe-supported over the obstruction until the obstruction has been fully traversed.

What is claimed is:

1. In an elevating type scraper for earth moving purposes, the combination comprising an open-fronted bowl having sides, back wall and floor, ground wheels for supporting the bowl and mounted behind the back wall, a scraper blade extending along the front edge of the floor, a tractor supported draft frame, a pair of draft members pivotally secured at the rear ends to the sides of the bowl and extending forwardly and upwardly having rigid connection at their front ends to the draft frame, means including an actuator interposed between the draft frame and the front end of the bowl and having control means for adjusting the degree of tilt of the bowl about its supporting wheels and hence the depth of cut of the blade, an elevator positioned at the open front end of the bowl, the elevator having a frame including a pair of frame members and which extends upwardly and rearwardly from the region of the blade and which is pivoted to the bowl for forward and upward swinging movement about a transverse axis, the elevator having a pair of endless chains with transversely arranged flights, the chains having means for driving at the upper end of the frame and trained about rollers at the lower end so that the flights sweep the soil loosened by the blade backwardly into the bowl, ground engaging shoes having adjustable mounts connected to the frame members for engaging the undisturbed ground surface slightly ahead of the flight envelope for supporting the elevator at a running height at which the flight envelope is maintained at a sweeping clearance above the undisturbed ground level, the shoes being movable on their mounts with respect to the elevator frame to adjust the maintained sweeping clearance, and means coupled to the mounts for positioning the shoes simultaneously in the same running position relative to the frame.

2. The combination as claimed in claim 1 in which the adjustable mounts are in the form of levers fulcrumed along a common axis at the lower ends of the frame members, the rearwardly extending ends of the levers presenting smoothly curved ground-engaging surfaces of sufficient total width to bear the weight of the elevator structure without appreciably penetrating the ground, the levers being rigidly interconnected by a torque tube to form an integrated shoe assembly in which the shoes are constantly maintained in the same phase position relative to the frame, and a shoe adjusting cylinder effectively interposed between at least one of the levers and the elevator frame for adjusting the frame with respect to the shoes and hence with respect to the undisturbed ground level.

3. The combination as claimed in claim 2 in which the torque tube is spaced ahead of the fulcrum axis and is rigidly secured between the forwardly extending ends of the levers so as to clear the envelope of the elevator flights.

4. The combination as claimed in claim I in which hydraulic actuators are interposed between the shoes and the respective frame members, the actuators being of substantially identical construction and hydraulically connected so that they are equally displaced to maintain the shoes constantly in the same phase position with respect to the frame.

5. The combination as claimed in claim 4 in which the actuators are of double-ended construction having piston rods extending in opposite directions and connected in series with one another and with a pressurized source of hydraulic fluid so that upon flow of fluid both actuators are moved in the same direction and by the same amount and so that when fluid flow is blocked the shoes are locked in the same phase position.

Claims

4. The combination as claimed in claim 1 in which hydraulic actuators are interposed between the shoes and the respective frame members, the actuators being of substantially identical construction and hydraulically connected so that they are equally displaced to maintain the shoes constantly in the same phase position with respect to the frame.