US3557934A

US3557934A - Frame-type dump scrapers

Info

Publication number: US3557934A
Application number: US796130A
Authority: US
Inventors: Fritz Schade
Original assignee: Gustav Schade Maschinenfabrik GmbH and Co
Current assignee: Gustav Schade Maschinenfabrik GmbH and Co
Priority date: 1968-02-12
Filing date: 1969-02-03
Publication date: 1971-01-26
Anticipated expiration: 1988-01-26
Also published as: FR2001716B1; FR2001716A1

Abstract

A dump scraper includes a frame having spaced-apart base portions adapted to be movably mounted on opposite sides of a dump. The frame includes legs extending upwardly toward one another from the base portions. A one-piece boom is pivoted to one of the base portions for pivotal movement in a vertical plane parallel to the legs. The boom receives support from the legs against substantial lateral deflection.

Description

United States Patent Inventor Fritz Schade Dortmund, Germany Appl. No. 796,130 Filed Feb. 3, 1969 Patented Jan. 26, 1971 Assignee Gustav Schade Maschinenfabrik Dortmund, Germany Priority Feb. 12, 1968 Germany 1,556,682

FRAME-TYPE DUMP SCRAPERS [5 6] References Cited FOREIGN PATENTS 691,314 4/1940 Germany 648,720 11/1962 GreatBritain ABSTRACT: A dump scraper includes a frame having spacedapart base portions adapted to be movably mounted on op- 7 Claims 5 Drawing Figs posite sides of a dump. The frame includes legs extending up- US. Cl 198/36, wardly toward one another from the base portions. A one- 214/10 piece boom is pivoted to one of the base portions for pivotal Int. Cl Bg 65/28 movement in a vertical plane parallel to the legs. The boom Field of Search 214/ 10; receives support from the legs against substantial lateral 198/36; 37/190, 191 deflection.

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ATTORNEYS FRAME-TYPE DUMP SCRAPERS The present invention relates to a dump scraper with a frame spanning the dump, which frame can be traversed along the dump on rails laid at either side thereof in the neighbor hood of the dump.

Dump scrapers are known which run on two rails located at one side of the dump. In these systems, the weight of the scraper boom has to be compensated for by a counterweight arranged at the side remote from the dump. The amount of space occupied by this kind of scraper system at that side of the dump from which it operates, is therefore relatively large and this is a drawback which is particularly severe in cases where the available ground area is very restricted. Since, with this kind of system, the scraper boom is fixed or held only at one end, the maximum boom length, which is what detennines the width of the dump, is limited because of loading factors.

Also known are frame-type scrapers with folding booms. A folding boom of this kind consists .of two sections with separate drive arrangements, chain sprockets and the like. It requires guide means at the boom tip and also an additional joint at the knee point. This makes the device a relatively complex one from the constructional point of view and it is therefore also expensive. Also, where the dump material has compacted at all, frequently transmission difficulties arise at the knee point in the boom. Finally, in this kind of system too, the maximum dump width which can be handled by the folding boom is limited by the same kind of factors which restrict the device just mentioned.

Again, dump scrapers of frame design are known which employ separate scraper booms operating at either side of the dump. Here, both the booms have'separate drives, separate pivot bearings and separate lifting gear. As a consequence of the doubling up of all the boom functions, the equipment becomes more complex and less reliable in operation.

It is the aim of the invention to overcome these drawbacks and to create a frame-type dump-clearing device which occupies less ground area, also requires less outlay in terms of joints, lifting gear, boom guides and scraper chain drives, thus being cheaper and more reliable in operation than known equipments, and which, finally, can also span very wide dumps.

In accordance with the invention, there is attached to the frame at a point thereon near the ground, at least one onepiece scraper boom able to pivot in a vertical plane, said boom having a length approximately equal to the width of the dump across its base and preferably extending, when in the raised position, out beyond the frame with its tip portion.

In accordance with a further essential feature of the invention, the arrangement is so contrived that the pivoting scraper boom is laterally supported against the leg of the frame opposite to the one to which its pivot bearing is fixed. With this kind of design of the frame-type scraper in accordance with the invention, the scraper boom is accordingly supported not only on the pivot bearing arranged near the base of the dump, but also, at a large interval from this bearing, upon that side of the frame which is opposite to the side at which the said bearing is located, the support in the latter case being lateral support against the horizontal forces acting upon the boom during operation of the system. Due to this lateral supporting of the scraper boom the boom length can be considerably increased without the horizontal forces acting upon the boom in the bending mode, becoming undesirably large with consequent bending deflection of the boom. The lateral supporting of the boom moreover provides the substantial advantage that the transverse forces stemming from the horizontal sheer forces are largely isolated from the pivot bearing of the boom. It is therefore possible to clear even very wide dumps using a single boom spanning the full width of the dump base.

In a preferred embodiment of the invention, the frame is provided with a fork or slot in that leg which is opposite the one carrying the boom pivot or bearing, in which fork or slot the forward portion of the scraper boom is located and can thus be supported against lateral forces. The boom is thus in this case guided in the frame slot at that of its ends opposite to the one through which it pivots, and depending upon the direction of traverse of the frame or the direction of action of the horizontal shear forces, is supported against one or other of the sides of the slot.

In accordance with a further essential feature of the invention, the dump scraper is equipped with two parallel-disposed scraper booms pivotable in a vertical plane, which supported laterally at either side of that leg of the frame which is opposite the leg carrying the boom pivots. The two booms are in this case located at the same side of the frame in the neighborhood of the base of the dump, preferably pivoting about a common pivot pin or coaxial pivot pins and at such an interval from one another that one boom can bear against the frame from one side and the other boom likewise from the other side. This kind of design of the dump scraper is distinguished in particular by high performance and simplicity of construction. The two parallel-arranged booms will preferably be linked with one another at their tips through a spacer or the like which permits a limited degree of relative vertical movement between the booms so that in operation they can be vertically staggered in relation to one another in each case by the amount of the depth of rake.

It is advisable to provide on the cooperating faces of frame and boom or booms, abutment and guide elements of wear-resistant material, preferably strips or the like, and in the case of the slotted frame leg both faces of the slot will have to be provided with elements of this kind.

Advantageously, in accordance with the invention, the lateral supporting of the boom or booms will be such that between the lateral abutment faces of boom and frame leg, there is a clearance which is less than the range of elastic deflection of the boom at that point. In this case, the lateral support will in all cases exclusively be provided in conditions in which the horizontal shear forces are still within the range of elastic deflection of the boom. It is thus possible to raise and lower the boom or booms without the said abutment and guide faces being in sliding contact with one another.

The invention will now be described with reference to the accompanying drawings, which illustratethe invention but in no restrictive sense.

FIG. 1 illustrates an elevational view of a frame-type dump scraper in accordance with the invention;

FIG. 2 illustrates a plan view of the dump scraper of FIG. 1;

FIG. 3 is an elevational view of a further embodiment of the dump scraper in accordance with the invention;

FIG. 4 illustrates the dump scraper of FIG. 3 in plan;

FIG. 5 is an end elevation of the connection between the two booms, at their tips, considering the dump scraper of FIGS. 3 and 4.

The dump scraper of FIGS. I and 2 has a frame I symmetrical about its own central plane, which spans the full width of the dump 2. The frame can be traversed along the length of the dump on wheels 3 which run upon rails 4 laid at both sides of the dump 2 beneath the level of the base 5 thereof. At one side of the dump, a trench 6 is provided running parallel with the rails 4 disposed there, and this trench contains a conveyor 7 and furthermore extends over the full length of the dump. Above the conveyor 7, a bracket 8 or the like is fitted to the frame, in which bracket a boom 10 is mounted to pivot about a horizontally disposed pin 9. The boom 10 is thus pivotable in the vertical plane and for the pivoting movement appropriate lifting gear is provided, consisting for example of a winch 11 the cable 12 of which is taken through a sheave of pulleys 13 to an attachment bracket 14, articulatingly connected to the boom. The attachment bracket 14 is connected to the boom at a point between the center thereof and the tip 15.

The scraper boom consists in the conventional way of the actual beam 10a on which the endless chains are so guided in the direction of the arrow P (said chains being connected together through scraper rakes 10b) that when the boom is lowered onto the slope 16 of the dump, the rakes engage the bulk material of the dump and scrape it in the direction towards the pivot bearing 9 and there it is fed over a platform 18 and a feed hopper 17 onto the conveyor belt 7. During the clearing operation, the frame-type scraper is traversed along the dump on the rails 4. After each pass, the scraper boom is lowered, using the lifting gear, by an amount corresponding to the depth of penetration of the rakes.

The frame 2 consists of the two legs la and lb inclined substantially parallel to the slope of the dump. The boom has a length such that at the leg lib it extends beyond the frame, and, in the fully lowered condition, shown in HQ. l in broken line, spans the full width of the dump. it is therefore possible, by means of the boom it) which is a one-piece design (i.e. has no intermediate joint) to clear the dump over its full width.

As FIG. 2 shows particularly well, the frame is provided in the leg llb as well as in the crosspiece lie, with a slot 19, the width of which is somewhat greater than the width of the boom across its external edges. The boom passes through the slot 19 and can be moved through it, the slot extending substantially over the full length of the leg. On the two sidewalls of the slot, narrow guide and abutment strips 20 and 21 are attached which extend substantially over the full length of the slot. The scraper boom 10 is provided likewise on both of its side faces which face the said strips, with narrow guide and abutment strips 22 and 23 which extend along the forward part of the boom, where it is guided in the slot in the leg lb of the frame. The guide and abutment strips consist of a wear-resistant material and are so disposed that whatever the angle of the boom, the boom strips can be laterally supported against the slot strips at one or other of the sides of the slot.

Between the mutually cooperating strips 20 and 23, and 21 and 22, in each case a small clearance 24 is available and this is within the range of elastic deflection of the boom. Under the effect of the horizontal shear force acting in the direction of the arrows Si or S2 and arising during the traversing movement of the frame along the dump, or as a consequence of possible wind loading, the boom is therefore able to bear on the one hand against the guide strip 2t) or on the other against that of strip 21, so that dangerously high deflections of the boom are prevented, even over long boom length, and the pivot bearing is protected against horizontal shear forces. if no horizontal shear forces are at work, then the boom is located centrally in a position in which its two strips 22 and 23 are out of contact with the corresponding strips 20 and 2i. in this condition, the boom can be swung by the lifting gear without the strips having any sliding contact with one another.

in the embodiment of FlGS. 3 to 5, the frame ll does not possess a slotted frame leg lib. The frame-type scraper is here equipped with two scraper booms 3t and 33 which are connected to the bracket 8 in such a way as to pivot about a common pin 9 or about two in-line pins. Each boom is provided with its own independent lifting gear ill to 14, this corresponding with the lifting gear shown in FIGS. 1 and 2. The two booms, which correspond with the boom it] of H68. 1 and 2 in design and length, are arranged one beside the other at an interval from one another slightly greater than the width of the frame legs la and 1b. The booms are moreover connected with one another at their tips through a stay or spacer 32 which fixes the interva! between the booms but permits a certain amount of relative vertical or pivoting movement on their part.

As FKG. 5 indicates, this device consists for exampie of a spacer 32 attached laterally to the boom 39, said spacer containing an elongated hole 33 in which a roller 34 engages, said roller in turn being mounted on a bracket 35 carried by the boom 31. The roller 34 is guided substantially without any play between rolling faces 36 defining the elongated hole. The elongated hole is of such length that the roller can move upwards and downwards from the central position indicated, in

each case by an amount corresponding to the depth of rake of the booms. The two

booms

30 and 31 are thus able to move in relation to one another in the vertical direction by an amount equivalent to approximately twice the depth of rake of the booms or the raltes 10b, so that during traversing of the frame along the dump in one or other of the two possi le directions,

the boom which is the rearward one considering the direction of travel, can be lowered further by the amount of the depth of rake, than the boom which is in the leading position.

in this case, the

booms

30 and 35 are provided with a guide and

abutment strip

37 and 38 exclusively at the particular side facing the leg in Accordingly, abutment and guide strips 39 and ll) are attached to the side faces of the frame leg against which the two booms with their corresponding strips bear throughout their range of swing whenever they require support. Between the strips 3'7 and 39, and 38 and 40, here again a clearance can in each case be provided which is within the range of elastic deflection of the boom at this point, so that physical contact between boom and frame leg only takes place in conditions under which the permissible deflection of the boom would otherwise be exceeded. Since the two booms have a fixed mutual interval, at all times only one of the two booms, generally the one which is leading in the direction of traverse, can bear against the side of the frame leg. The other boom will then be prevented from undergoing excessive deflection by the cooperation of the spacer arrangement 32 with the laterally supported boom,

In order to substantially isolate the pivot bearing 9 from the action of any transverse forces, it is advisable to arrange for the clearance between guide and abutment strips on the boom or booms and the frame leg, to be small. The clearance may in fact be made virtually zero. It is even possible to arrange for the boom or booms to be supported positively against the frame leg, through the medium of rollers.

Having thus described my invention, l claim:

1. A dump scraper having first and second spaced-apart base portions adapted to be movably supported at opposite sides of a dump, said frame including first and second leg means extending upwardly toward one another from said first and second base portions respectively, one-piece scraper boom means pivotally connected to said first base portion for pivotal movement in a substantially vertical plane parallel to said leg means, said boom having a length not substantially less than the spacing between said first and second base portions, said boom including a tip portion and having a length such that said tip portion projects beyond said second leg in raised positions of said boom.

2. The device of cla'm 1 wherein said scraper boom means is supported against substantial lateral deflection by said second leg means.

3. The device of claim 2 wherein said scraper boom means has a lateral elastic deflection limit defined by a predetermined lateral distance, said scraper boom means being laterally spaced from said second leg means a distance less than said predetermined distance.

4. The device of claim 2; and further including abutment and guide means on said scraper boom means and said second leg means.

5. The device of claim 2 wherein said second leg means includes elongated slot means and said scraper boom means extends through said slot means.

6. The device of claim 2 wherein said scraper boom means includes two parallel spaced-apart scraper booms positioned on opposite sides of said second leg means.

7. The device of claim 6 wherein said two scraper booms have tip portions and said tip portions are connected by spacer means, said spacer means including lost motion means for providing limited vertical movement between said two booms.

Claims

2. The device of claim 1 wherein said scraper boom means is supported against substantial lateral deflection by said second leg means.

4. The device of claim 2 and further including abutment and guide means on said scraper boom means and said second leg means.