WO1994011583A1

WO1994011583A1 - Earth moving apparatus

Info

Publication number: WO1994011583A1
Application number: PCT/NZ1993/000107
Authority: WO
Inventors: Nicolaas Laurisse Sieling
Original assignee: ROTACON Engineering Ltd
Current assignee: ROTACON Engineering Ltd
Priority date: 1992-11-08
Filing date: 1993-11-05
Publication date: 1994-05-26
Anticipated expiration: 1995-05-08
Also published as: AU5379294A

Abstract

A self-loading earthmoving scraper (10) is disclosed which includes a bowl (12) for picking up, transporting and discharging a load of earth. The bowl comprises a curved floor (20) and a mounting arrangement (34) for a blade (30) which is suspended in the bowl. The blade is mounted in rails (32) incorporated in the mounting arrangement so that it can slide up and down under the action of a first hydraulic ram (44) also incorporated in the mounting arrangement. In its lowest position its lower edge is close to the bowl floor and its highest position the lower edge is raised above the load in the bowl. The mounting arrangement is pivotably mounted on the scraper so that the blade can swing back and forth in the bowl under the action of a second hydraulic ram (46) which is actuable independently of the first ram. In its forwardmost position the blade is substantially forward of the front edge of the floor. In its rearmost position the blade is at the back edge of the floor. The blade can be moved to any position between the lowest and the highest positions when it is in any position between the forwardmost and the rearmost positions. In the lowest position the lower edge of the blade describes an arc which is close to the curved floor. The scraper is provided with wheels (18) which are mounted by a suspension arrangement (70-78) incorporating hydraulic rams (74) for adjusting the operating level of the wheels relative to the bowl. The bowl may be provided with a downwardly projecting hump (90) which extends across the floor behind the front edge thereof.

Description

TITLE: EARTH MOVING APPARATUS

FIELD OF THE INVENTION

This invention relates to an apparatus which is known in excavating jargon as a scoop or scraper. The skilled reader will, on reading this specification, readily understand the type of apparatus referred to and such apparatus will for convenience be referred to herein as a scraper.

BACKGROUND OF THE INVENTION

A scraper is a wheeled vehicle designed to pick up a load of earth in one locality and deposit it at a remote locality. For this purpose it is provided with a bowl for containing the load. The bowl is essentially an open topped box, comprising a floor from which arise side walls, usually a front wall called the apron and a rear wall called the ejector. The front edge of the floor and the lower portions of the front edges of the side walls adjacent the floor are provided with cutting edges which, when the bowl is lowered, dig into the earth and cut a swath of earth which feeds into the bowl as a result of the forward motion of the scraper. The apron is raised during this operation. When the bowl is full the apron is lowered to prevent the load from spilling out of the front of the bowl. The bowl is discharged at the dumping site by raising the apron and moving the ejector forward, or tipping the bowl forward, as the scraper moves forward with the bowl being kept at a controlled height above the ground. The floor of the bowl passes over the discharged load, spreading it flat in the process.

Scrapers are drawn by tractors which may be an integral part of the apparatus or independent thereof. The tractors may be rubber tyred or tracked. It is very common to find that a scraper which is propelled by a rubber tyred tractor requires the assistance of a second tractor (or other vehicle) which either pushes or pulls the scraper during the bowl-loading operation. This is because both digging and filling set up a lot of resistance and rubber tyred tractors often do not have sufficient traction to overcome the combined resistance even when, as commonly usually happens, the earth has been loosened by bulldozing, ripping or blasting operations prior to being picked up by the scraper. Track type tractors have a lot more traction and can usually fill the scraper without assistance. But track type tractors are much slower over the ground than rubber tyred tractors and are often not suitable from an economic point of view where the load must be dumped more than a short distance from where it is picked up.

To overcome this problem, some scrapers are provided with an elevating apparatus for assisting the loading. This apparatus comprises a series of flights slung between a pair of sprocket chains mounted one on either side of the bowl at the front end thereof. The sprockets are positioned so that the flights not only dig into the ground just ahead of the cutting edges of the bowl floor but also carry the cut earth rearwardly and upwardly into the bowl. The elevating apparatus enables scrapers with rubber tyred tractors to be self loading without outside assistance.

The conventional elevating apparatus has at least two disadvantages. First, it is susceptible to damage and break-down. Second, it occupies a lot of space and reduces the carrying capacity of the scraper substantially. It is also costly.

It is an object of the invention to provide an alternative apparatus for assisting the loading of a scraper.

SUMMARY OF THE INVENTION

According to the invention there is provided a scraper including a bowl for transporting a load of earth and comprising a floor with a front edge provided with means which, during forward motion of the scraper over the ground, cuts a swath of earth which feeds into the bowl during said forward motion, characterised in that the scraper is provided with a blade mounted in the bowl so that a portion thereof incorporating a lower edge of the blade can engage the load, the blade being mounted in the bowl by means including retracting means operable to move the blade between a forward position and a retracted position in the bowl, and lifting means operable independently of the retracting means to move the blade between a low position and a raised position in the bowl, so that the blade can be moved to any position between the low position and the high position when it is in any position between the forward position and the retracted position.

In one form of the invention the bowl is provided with spaced side walls which rise from the floor and the blade is disposed between the side walls.

In one aspect of the invention the mounting means comprises a frame incorporating slide means in which the blade can slide between the low position and the raised position.

In another aspect of the invention the frame is pivotably mounted on the scraper so that the blade undergoes pivotal movement when it is moved between the forward position and the retracted position.

According to an important aspect of the invention the floor of the bowl is shaped to conform to a sector of a cylinder having an axis of curvature coincident with a pivotal axis about which the slide means pivots, the floor having a rear end located behind and at a higher level than the front edge.

It is one advantage of the invention that the lifting means can move the blade so that when it is in the low position the lower edge thereof is located in close proximity to the floor of the bowl and that the lifting means is arranged to lift the blade so that when it is in the high position the lower edge of the blade can pass over the top of a full load in the bowl when the blade is moved from the forward position to the retracted position.

It is another advantage of the invention that the retracting means can move the blade so that when it is in the retracted position the lower edge is located at or close to the rear end of the floor of the bowl.

In one aspect of the invention said portion of the blade which engages the load has a substantially flat front face which pushes the load forwards when the blade is moved from the retracted position to the forward position and a substantially flat back face which pushes the load backwards when the blade is moved from the forward position to the retracted position. In yet another aspect of the invention the scraper comprises mounting means for wheels which include adjustment means for adjusting the wheels vertically relative to the bowl.

According to a feature of the invention a protuberance is provided which is located behind the front edge of the floor, extending across the bowl and projecting below the floor.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

An example of the invention is illustrated in Figure 1 of the accompanying drawing which is a cross sectional side elevation of a scraper. The scraper 10 comprises a bowl 12. The bowl 12 comprises a frame 14 provided at its forward end with a hitching arrangement 16 by means of which the bowl can be connected to a standard agricultural tractor. The hitching arrangement will be described in further detail.

Rubber tyred wheels 18 are mounted on the bowl at its rear end by means which, again, will be described in further detail.

The bowl 12 comprises a floor 20 and a pair of vertical side walls 22. Only one of these side walls can be seen in the drawings. Cutting edges 24 are mounted on the front edge of the floor and the lower portions of the front edges of the side walls.

Arising from each side wall 22 is an A-frame 26 which forms part of the frame 14. The A-fra es are joined at their upper ends by a cross beam 28. A substantially flat fabricated blade 30 is slidably mounted between two rails 32 comprised of channel sections and located at the ends of a frame 34a. Behind the blade the rails are spanned by cross members 34b. The frame 34a and the cross members 34b constitute a mount

34 for the blade 30. The blade spans the bowl crosswise, fitting neatly but slidably between the two side walls 22. The frame 34a is provided with lugs 38 by means of which the mount 34 is pivotably connected, through pins 40, to lugs 42 mounted at each end of the cross beam 28. A first double acting hydraulic ram 44 is connected at one end to the centre of the upper edge of the blade 30 and at the opposite end to the centre of the lower cross member 34b. Thus the ram 44 can be actuated to raise or lower the blade in the mount 34. A second double acting hydraulic ram 46 is connected at one end to a lug 47 mounted at the centre of the lower edge of the frame 34a. The ram 46 is connected at its opposite end to a trunnion plate 48 welded to, and forming part of, the frame 14. A strut 50 connects the top of the trunnion plate to the cross beam 28 for stiffening purposes. Actuation of the ram 46 causes the mount 34 and hence the blade 30 to pivot about the pins 40.

The floor 20 of the bowl is curved to conform to the shape of a sector of a right circular cylinder having its axis coincident with the common axis of the pins 40. Thus, wherever the blade 30 is positioned by the ram 44 in the mount 34, the radial distance between the lower edge of the blade and the floor 20 remains constant when the mount 34 is pivoted by the ram 46. This is indicated in the first place at 52 in which condition the mount 34 has been drawn by the ram 46 to its maximum forward or advanced position; and, as indicated at 54, in which condition the mount 34 has been pushed by the ram 46 to its maximum rearward or retracted position. In the uppermost position of the blade 30, the lower edge thereof describes an arc 56' of a circle when the mount moves between the fully advanced and fully retracted positions. In the lowermost position of the blade 30 the arc (as indicated at 56") is substantially coincident with the floor. The arc can be positioned anywhere between the two extremes indicated at 56' and 56" depending on the setting of the blade in the mount

The hitching arrangement 16 comprises a hitching pin 60 which is pivotably mounted in a box-like extension 62 of the frame 14. This extension 62 is located at the longitudinal centre of the scraper and is canted upwardly from the general plane in which the frame 14 lies so that, when the scraper is in its working position as illustrated in the drawing, the extension is substantially horizontally disposed. The hitching pin 60 is mounted with its longitudinal axis horizontal and in the fore-and-aft direction of the scraper. At its forward end an eye is formed in the hitching pin, the axis of the eye being vertical. The eye of the hitching pin fits into a beam 64 mounted between the two lower mountings of a standard three point hitch on the tractor. The hitching pin 60 is coupled to the beam 64 by means of a vertical coupling pin 66 which is mounted at the centre of the beam 64 and passes through the eye of the hitching pin. The scraper is thus substantially free to move in relation to tractor when the two are two are hitched together.

The wheels could be mounted in fixed positions on the scraper. However, in the case illustrated, each wheel 18 is mounted on a stub axle projection outwardly from the rear end of a beam 70. The forward end of the beam 70 is carried on a pin 72 joumalled between two pipes fixed to the scraper floor 20. A single acting hydraulic ram 74 is mounted between lugs 76 welded to the back end of the scraper floor and lugs 78 welded to the top of the beam 70 forward of the rear end thereof. The beams 70 are independently mounted. This mounting arrangement of the wheels much facilitates the setting of the bowl in various desired working positions. The scraper is thus not dependent on the setting of the three point hitch for controlling the depth of cut, for example, or for lifting the scraper clear of the ground for transporting the load after the bowl is filled. The height of the wheels can also be independently adjusted to set the bowl in a tilted position.

To load the scraper, the blade is raised and advanced to the position shown at 52. The wheels are then raised thus lowering the bowl until the cutting edges 24 engage the ground. The beam 64 could also be lowered by the three point hitch but this would not usually be necessary. The cutting edges thus dig a swath of earth as the tractor is moving forward, as shown in the drawing. This earth feeds into the bowl and initially builds up into a mound indicated schematically at 80. As will be understood by those skilled in the art, the load tends to build up ahead of the cutting edges as shown. It is a very useful characteristic of the design of the scraper 10 that the blade can now be dropped and retracted to push the load 80 to the back of the bowl. This cycle can be repeated until the bowl is full as indicated at 82. The blade can then be advanced and dropped so that the lower edge is located substantially at the cutting edge 24 of the floor. The blade thus effectively closes the front of the bowl in the manner of a conventional apron.

The load is discharged from the bowl by lifting the blade 30 and moving it to the fully retracted position shown and 54 and then lowering it to floor level. The blade swings clear of the top of the load in this movement It is then advanced so that it drives the earth in the bowl forward with the front of the bowl raised some distance above ground level and with the tractor moving forward. Where the load offers relatively low resistance, as with dry soil, the bowl may be fully discharged with a single pass of the blade as described. However, in some cases two passes may be required, the blade being positioned at, say, half way between the floor and its uppermost position before commencing the first pass. It is fully lowered before commencing the second pass. The design has a number of substantial advantages. It is simple to construct. The curved floor and the monolithic frame contribute substantial strength and rigidity to the structure. The blade 30 performs various functions. It retains the load in the bowl when it is full, thus serving as the front wall of the bowl and replacing the apron of a conventional scraper as described. It can be retracted right to the back end of the bowl floor and then lowered to push the load out of the bowl in the discharging operation. It thus replaces the ejector in the conventional scraper. Furthermore, in the fully advanced position of the blade, its lower edge is well forward of the cutting edge of the floor. From this position it can be retracted to push the earth into the bowl. The scraper is thus self loading. The mount 34 and blade 30 replace the conventional self loading apparatus. Because (unlike the conventional self loading apparatus) the mount and the blade take up virtually no space in the bowl, the capacity of the scraper is substantially increased. Moreover the mount and blade are not so susceptible to damage and wear as the chains of the conventional self loading apparatus.

In a modification of the scraper 10, a hump 90 is located under the floor 20, just behind the cutting edge 24. The hump extends the full width of the bowl. It projects downwardly a distance selected so that, when the bowl is in its work position shown in the drawing, the hump is located just above the newly cut surface 92 of the earth. It often happens that the front end of the scraper drops when it is moving forward. This occurs, for example, when the tractor is traversing uneven terrain and moves into a dip in the terrain. When this happens the hump comes into contact with the surface 92 and tends to prevent the cutting edge from dropping and making a deeper cut The provision of the hump thus helps to keep the surface level. It also helps to level out the earth which is deposited on the ground when the bowl is unloaded.

It is a very useful feature of the design, arising from the curvature of the floor, that the load can be discharged by pushing it out of the bowl so that it falls over the rear edge of the floor. By backing the scraper and discharging the load in this manner, the load can be can be dumped in places which cannot be approached by a conventional scraper.

Variations are envisaged to the above described constructions. For example, the blade

30 need not be suspended from A-frames 26. Instead it may be mounted at the forward end of a yoke the rear end of which is pivotably mounted on a dolly which in turn is mounted on a sub-frame located behind, and fixed to, the bowl. This sub-frame may also carry the road wheels of the scraper. The yoke projects forwardly and it may pass over the rear of the bowl or it may pass outside each side wall of the bowl. In either case the yoke can be pivoted up or down by one or more rams anchored on the sub- frame or dolly. Extension of the rams lifts the front end of the yoke and hence the blade

30. The blade may be fixed to the yoke in which case it may derive its fore-and-aft movement by virtue of the dolly being slidably mounted on the sub-frame, actuated by a ram. Alternatively, the blade 30 may be pivotably suspended from the front of the yoke, its fore-and-aft movement being derived from a ram located in front of the blade, similarly to the ram 46 on the scraper 10.

This latter construction is particularly suited to a bowl with a flat floor and integral rear wall. Another advantage is that this scraper is likely to have a lower centre of gravity than the scraper shown in the drawing.

The drawing is to scale. The nominal height of the side walls of the bowl shown in the drawing is 1J5 metres. The length of the floor from the cutting edge to the rear end along the curve is 2.60 metres. The radius of curvature of the floor is 1.80 metres. The width of the bowl is 2.40 metres. The capacity of this scraper is 4.50 cubic metres.

It is not intended that the scope of a patent granted in pursuance of the application of which this specification forms a part should exclude modifications and/or improvements to the embodiments described and/or illustrated which are within the scope of the invention as defined in the claims or be limited by details of such embodiments further than is necessary to distinguish the invention from the prior art.

Claims

1. A scraper [10] including a bowl [12] for transporting a load of earth and comprising a floor [20] with a front edge provided with means [24] which, during forward motion of the scraper over the ground, cuts a swath of earth which feeds into the bowl during said forward motion, CHARACTERISED IN THAT the scraper is provided with a blade [30] mounted in the bowl so that a portion thereof incorporating a lower edge of the blade can engage the load, the blade being mounted in the bowl by means including retracting means [46] operable to move the blade between a forward position and a retracted position in the bowl, and lifting means [44] operable independently of the retracting means to move the blade between a low position and a raised position in the bowl, so that the blade can be moved to any position between the low position and the high position when it is in any position between the forward position and the retracted position.

2.

A scraper according to claim 1, CHARACTERISED IN THAT the bowl is provided with spaced side walls [22] which rise from the floor and the blade is disposed between the side walls.

3.

A scraper according to claim 1 or claim 2, CHARACTERISED IN THAT the mounting means comprises a frame [34a] incorporating slide means [32] in which the blade can slide between the low position and the raised position.

4.

A scraper according to claim 3, CHARACTERISED IN THAT the frame is pivotably mounted [40] on the scraper so that the blade undergoes pivotal movement when it is moved between the forward position and the retracted position.

5.

A scraper according to claim 4, CHARACTERISED IN THAT the floor of the bowl is shaped to conform to a sector of a cylinder having an axis of curvature coincident with a pivotal axis about which the slide means pivots, the floor having a rear end located behind and at a higher level than the front edge.

6. A scraper according to claim 5, CHARACTERISED IN THAT the lifting means can move the blade so that when it is in the low position [56"] the lower edge thereof is located in close proximity to the floor of the bowl and that the lifting means is arranged to lift the blade so that when it is in the high position [56'] the lower edge of the blade can pass over the top of a full load in the bowl when the blade is moved from the forward position to the retracted position.

7.

A scraper according to claim 5 or claim 6, CHARACTERISED IN THAT the retracting means can move the blade so that when it is in the retracted position the lower edge is located at or close to the rear end of the floor of the bowl.

8.

A scraper according to any one of claims 1 to 7, CHARACTERISED IN THAT said portion of the blade which engages the load has a substantially flat front face which pushes the load forwards when the blade is moved from the retracted position to the forward position and a substantially flat back face which pushes the load backwards when the blade is moved from the forward position to the retracted position.

9. A scraper according to any one of claims 1 to 7, CHARACTERISED IN THAT it comprises mounting means [70-78] for wheels [18] which include adjustment means [74] for adjusting the wheels vertically relative to the bowl.

10. A scraper according to any one of claims 1 to 9, CHARACTERISED IN THAT a protuberance [90] is provided which is located behind the front edge of the floor, extending across the bowl and projecting below the floor.