GB2049383A

GB2049383A - Scarifier

Info

Publication number: GB2049383A
Application number: GB8013435A
Authority: GB
Original assignee: Fiat Allis Macchine Movimento Terra SpA
Current assignee: Fiat Allis Europe SpA
Priority date: 1979-04-24
Filing date: 1980-04-23
Publication date: 1980-12-31
Also published as: GB2049383B; BR8001651A; FR2472342A1; IT1118956B; AU5609280A; JPS55145221A; IT7967861A0; DE3007558A1

Abstract

A scarifier device (1) and a hydraulic system for controlling movement thereof for a tractor comprises a quadrilateral type linkage (2,4,6,32) having fluid operated actuating means (16) extending between a lower swivel arm (6) and a tool carrying frame (2) which form two sides of the linkage. In combination with the hydraulic system the drive enables the operator to move the device in a radial and parallelogram motion and further allows variation of the angle of incidence of the tool carrying movable frame. <IMAGE>

Description

SPECIFICATION Scarifier device for an earth moving machine Background of the invention This invention relates to a scarifier or ripper device for attaching to an earth moving machine, such as a tractor or other vehicle, for carrying out ground excavation operations.

A scarifier or ripper device essentially comprises a linkage having a fixed frame which is attached to the vehicle, a movable or tool carrying frame to which a tool is attached, and one or more arms which pivotally connects the fixed frame to the tool carrying frame. The typical scarifier device enables the tool to make one or more geometrical movements as hereinafter described. A first movement, defined as radial, includes making the tool point (or points) undergo a substantially circular trajectory about a suitable horizontal axis of rotation which passes through a point in the fixed frame. By means of this movement, the working part of the tool is able to penetrate into the ground, and describe therein a trajectory substantially in the form of a circumferential arc.A second movement, known as variation of the angle of incidence, includes rotating said movable frame about an axis passing through the movable frame itself and orthogonal to the plane in which said radial movement takes place. This movement alters the angle of incidence between the working part of the tool and the ground. Finally, a third movement, know as parallelogram movement, includes moving the tool carrying frame, and therefore the tool, such that the angle of incidence between the working part of the tool and the ground remains almost unchanged. By means of this movement, the tool tends to penetrate into the ground with a curved trajectory, the curvature depending on the dimensions of the members of the linkage. If the members of the linkage form a true parallelogram the angle of incidence will remain constant.

The prior art scarifier devices can be differentiated from one another by the structure of the linkage which connects the mobile frame to the fixed frame, and by the configuration of the operating means, usually hydraulic, which control the movement of the linkage. In the prior art devices, the three types of aforementioned movements cannot always be precisely performed, or alternatively, the movements are not completely independent of one another, because of the structure of the linkage and the type of control means utilized. Finally, some devices require rather complex structures in order to perform the required movement. The prior art includes various linkage arrangements for scarifier devices and means for controlling the movement of linkage, usually hydraulic. U.S.Patent Nos. 3,503,456; 3,527,308; 3,973,632; and 4,031,964 show various linkage arrangements and hydraulic means for controlling movement thereof.

The present invention provides a scarifier device for an earth moving machine or other vehicle comprising a linkage in the form of an articulated quadrilateral. One pair of opposing sides of the quadrilateral are formed buy a movable or tool carrying frame and a fixed frame which rigidly attaches the device to the machine. The other opposing sides of the quadrilateral are formed by lower and upper swivel arms, each of which is hingedly connected to the fixed and movable frame.

The linkage is operated by an actuating means that is hingedly connected between the lower swivel arm and the movable or tool carrying frame. The upper swivel arm can advantageously comprise a second fluid operated actuating means hingedly connected between the fixed and movable frames. The hydraulic control system enables the linkage to perform radial movement, allows variation in the angle of incidence of the tool with respect to the ground and further allows parallelogram movement.

It is, therefore, an object of this invention to improve scarifiers or rippers utilized on tractors or other similar vehicles.

Another object of this invention is to improve ripping devices that utilize a parallelogram type linkage.

It is yet another object of this invention to provide a ripping device that allows radial movement, parallelogram movement and variation of the angle of incidence of the scarifier tool.

Description ofthe drawings Further objects of the invention together with additional features contributing thereto and advantages accruing therefrom will be apparent from the following description of the preferred embodiments which are shown in the accompanying drawings with like reference numerals indicating corresponding parts throughout, wherein:: Figure 1 is a side view of one embodiment of the invention, with the scarifier tool shown lowered into the ground; Figure 2 is a side view of a second embodiment of the invention wherein the upper swivel arm of the linkage comprises hydraulic actuating means; Figure 3 is an end view of the scarifier device shown in Figure 2; Figure 4 is a diagram of the hydraulic circuit utilized in controlling the embodiment of the invention shown in Figure 1; Figures 5, 6, and 7 are diagrams of hydraulic circuits utilized in controlling the embodiment of the inventions shown in Figure 2.

Description of the preferred embodiment With reference initially to the embodiment of Figure 1, the scarifier device, indicated generally by the reference numeral 1, comprises a movable or tool carrying frame 2 to which one or more tools 3 is attached, and a fixed frame 4 for connection to the machine (normally to the rear thereof). A linkage 5, connects the movable frame to the fixed frame 4 in order to allow the former to move relative to the latter. The linkage comprises substantially at least one lower arm 6, which is hinged at one end to a pivot point 7 on the fixed frame 4 and the other end to a pivot point 8 on the movable or mobile frame 2.

As shown in Figures 1 and 2 the lower arm includes a pair of longitudinal members 9 connected rigidly together by a cross member 10. The linkage 5 also comprises an upper arm 13, one end of which is hinged to a pivot point 14 on the fixed frame 4, and the other end of which is hinged to a pivot point 15 on the mobile frame 2. In the embodiment shown in Figure 1, the upper arm 13 comprises a single link disposed substantially in a vertical plane which is equidistant from each of the longitudinal members 9.

The assembly formed by the two arms 6 and 13 and the frames 2 and 4 therefore comprises an articulated parallelogram linkage assembly arranged to cause the tool carrying frame 2 to move in a vertical plane, while substantially maintaining the same angle of incidence with respect to the ground.

As can be clearly seen in Figure 1, the distance between the hinging points 7 and 8 of the lower arm 6 is greater than the distance between the hinging points 14 and 15 of the upper arm 13. By utilizing the elements of this geometrical structure and by means of a suitable choice of the other dimensions of the elements of the parallelogram, any change in angular position y (gamma) of the tool 3 with respect to the ground can be preselected. In the case of the embodiment illustrated, it is considered appropriate to vary the angle of incidence y of the tool about 59 or from 40 in passing from a first position wherein the tool 3 is at its maximum depth to 45" wherein the tool 3 is at ground level (indicated by the dashed line in Figure 1).

The linkage 5 is operated by fluid operated actuating means, such as hydraulic cylinders 16. Each of the hydraulic cylinders includes a tubular casing or housing which is hinged to a pivot point 17 on the arm 6, and a rod 18 slidably moveable within the casing is hinged to a pivot point 19 on the mobile frame 2. Pivot point 17 is located on a vertically upwardly projecting portion 20 of the arm 6 and is disposed or located in immediate proximity to the pivot point 7 which hinges the arm 6 to the fixed frame 4. The position of the point 17 relative to the point 7 is chosen so that the former is disposed above the latter, as clearly seen in Figure 1. The hinging point 17 is positioned between the hinging points 7 and 8 of the arm 9.The hinging point 19 has been chosen so asto be disposed higher than the point 15 at which the arm 13 is hinged to the mobile frame 2. In order to facilitate ease of operation of the assembly, each of the hinged points 19 is connected to a pair of brackets or lugs 21 in turn rigidly attached to the frame 2.

In the embodiment illustrated, the lower arm 6 is provided with a bracket or buffer element 22 arranged to rest against a suitable stop or seat 23 on the fixed frame 4 when the mobile frame 2 is moved into its upward limiting position, shown by the dashed line in Figure 1.

The hydraulic circuit for controllirig the described device is diagrammatically illustrated in Figure 4.

The circuit comprises a central hydraulic unit (not shown) arranged to feed pressurized fluid through a pipe or conduit 25 to the cylinders 16 and to discharge the fluid through a pipe or conduit 26 into a discharge vessel 27. Between the conduits 25, 26 and the cylinders 16 there is disposed a distributor valve 28 connected by pipe or conduit portions 29 and 30 respectively to head and rod end chambers 40,41 of each of the cylinders. The distributor valve 28 can assume at least two different positions, each of which changes fluid flow conditions between the pipe portions 25,26, and 29,30 in a manner which will be described hereinafter.

As best shown in Figure 2, the arm 13 of the linkage connecting the mobile frame 2 to the fixed frame 4 can be replaced by a second hydraulic cylinder 32. One end of the casing of said cylinder is hinged to the pivot point 14 on the fixed frame 4and one end of a piston rod 33 is hinged to the pivot point 15 on the mobile frame 2. Consequently the hydraulic cylinder 32 (which is hinged to the same points in which the upper arm 13 was hinged to the frames 2 and 4) is geometrically equivalent to the arm 13.

In the embodiment shown in Figure 2, the first and second hydraulic cylinders, 16 and 32 respectively, can be operated by either of the two hydraulic circuits shown in Figure 5 and Figure 7. In Figure 5, the two hydraulic cylinders 16 are operated buy a distributor valve 28, completely analogous to that described with reference to the circuit of Figure 4.

The cylinder 32 is operated by a second distributor valve 34 connected between the first distributor valve and pipe portions 35 and 36, which are connected respectively to a rod chamber 39, and a head chamber 38 of the cylinder 32. The distributor valve 34 can assume substantially two positions, shown in Figures 5 and 6 respectively, so as to determine two different operating conditions which will be described hereinafter.

The hydraulic circuit of Figure 7 completely corresponds to that of Figure 5 with the exception that the distributor valve 34 is replaced by a distributor valve 37 able to assume three different operating positions.

Operation ofthe invention With reference to the embodiment of Figure 1, the operation will be discussed starting from the downward limiting position of the linkage 5, in which the tool 3 is at its maximum depth in the ground as shown in Figure 1. To lift the tool, the distributor valve 28 (Figure 4) is operated by moving it towards the right in Figure 4, so as to hydraulically connect the pipe portion 25 to the pipe portion 29 in order to feed pressurized fluid into the chambers 40 in the cylinders 16. Simultaneously the pipe portion 26 is connected to the pipe portion 30 to enable the fluid contained in the chambers 41 of the cylinders 16 to discharge to the vessel 27. In this manner the rod 18 of each of the cylinders 16 is moved towards the right in Figure 1,therby rotating the swivel arms 6 and 13 counter clockwise, and thus raising the mobile frame 2. The limiting position reached at the end of this movement is shown by the dashed line.

In an entirely similar manner, by operating the distributor valve 28, the cylinders 16 can be operated so that they lower the frame 2.

In this manner, the scarifier device according to the invention makes a parallelogram movement, in which the tool 3 moves vertically while its angle of incidence with respect to the ground remains essen tially constant. It is apparent that by suitably choosing the dimensions of the various elements making up the articulated parallelogram which controls the tool movement, any required variation in the angle of incidenceyofthetool along its trajectory can be obtained. In this respect, it is considered appropriate to choose these dimensions such that the angle of incidence y changes from 40 to 450 in passing from the position of maximum depth in the ground to the position of contact with the ground surface respectively.

With the embodiment of Figure 2, two different modes of operation can be obtained in addition to that involving the parallelogram movement just described with reference to the embodiment of Figure 1. A first mode consists of again moving the tool with a parallelogram movement, but with preselected angle of incidence y for the tool, which is chosen by the operator according to the work to be done and which is kept unchanged during the parallelogram movement. A predetermined angle of incidence y for the tool is set by first operating the distributor valve 34 by moving it from the configuration shown in Figure 5 to the configuration of Figure 6. As shown in Figure 6, hydraulic connections are made through distribution valve 34 between conduit portions 29 and 35, 29' and 36 and 30' and 30.In this manner the hydraulic cylinder 32 becomes con nected in series with the two hydraulic cylinders 16.

The distributor valve 28 is then operated by moving it towards the right as shown in Figure 6 so as to hydraulically connect together the conduits 25 and 29', and 26 and 30'. Pressurized fluid is delivered to the head end chamber 38 of the cylinder 32, and discharged from the rod end chamber 39 into the head end chambers 40 of the cylinders 16. The fluid discharged from the rod end of chambers 41 of the cylinders 16 is then delivered to the discharge vessel 27.

The distributor valve 34 is then returned to the position of Figure 5, in which any feed or discharge of fluid to the head end chamber 38 or from the rod end chamber 39 of the cylinder 32 is prevented. Conse quently the cylinder 32 functions as a rigid arm of predetermined length. Additionally, by operating the distributor valve 28 as previously described with reference to the first embodiment, the hydraulic cylinders 16 can be operatively positioned to any preselected position.

A second mode of operation is to carry out a parallelogram type movement while simultaneous ly pivoting the frame 2 about the axis of the hinge point 8. The distributor valve 34 is moved to the position shown in Figure 6 and allowed to remain in that position. With the cylinders 32 and 16 thereby connected in series, operating the distributor valve 28 by moving it to the left will then cause the tool 3 to pivot about hinging point 8 as it enters the ground.

This particular mode of operation can be useful in special operating circumstances. With a specific choice of dimensions of cylinders 16 and 32 it is possible to give to the point of tool 3 a substantially predetermined value of movement. For example, the point of the tool 3 may be moved in a substantially horizontal direction by choosing the dimensions of cylinders 16 and 32 such that the combined crosssectional areas of the head end chambers 40 of the cylinders 16 are essentially equal to the crosssectional area of the rod end chamber 39 of the cylinder 32.

A third mode of operating the device in the embodiment of Figure 2 can be obtained by utilization of the hydraulic circuit of Figure 7. In this respect, if the distributor valve 37 is moved into the position shown in this latter figure and the distributor valve 28 is moved towards the left in Figure 7, the conduit portions 29' and 30' become connected to the pipe portions 35 and 36 respectively, so as to deliver pressurized fluid into the rod end chamber 39 of the cylinder 32 and to discharge it from the head end chamber 38 of the cylinder 32. In this configuration, the pipe portions 29 and 30 remain closed, thereby preventing any feed or discharge of fluid to or from the the head or rod ends of chambers 40 and 41 respectively of the cylinders 16.In this manner, the assembly structured by the lower arm 6, the frame 2 and the cylinders 16 operates as a rigid structure and swivels about the hinging point 7, under the control of the hydraulic cylinder 32. In this manner, operation with radial movement is obtained, i.e. in which the point of the tool 3 travels through a circular trajectory about the hinging point 7.

While the invention has been described with reference to preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof.

Therefore, it is intended that the invention not be limited to the particular embodiments disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims

1. Ascarifierdeviceforan earth moving machine including a linkage in the form of an articulated quadrilateral having a movable frame to which a scarifier tool is fixed, a fixed frame connected to the machine and a pair of substantially parallel upper and lower swivel arms, each of which is hingedly connected to a pivot point on said fixed frame and to a pivot point on said movable frame, comprising: fluid operated actuating means for operating said linkage, and hinge means pivotally connecting said actuating means to said lower swivel arm and to said movable frame.

2. The scarifier device according to Claim 1, wherein said actuating means comprises a hydraulic cylinder having a piston rod and a casing; said hinge means pivotally connects said rod to said movable frame and said hinge means pivotally connects said casing to said lower swivel arm.

3. The scarifier device according to Claim 1, wherein said hinge means for pivotally connecting said lower swivel arm to said actuating means is located between said pivot points at which said lower swivel arm is hinged to the fixed and movable frames, and above the pivot point at which said lower swivel arm is hinged to the fixed frame.

4. The scarifier device according to Claim 3, wherein said hinge means for pivotally connecting said actuating means to said movable frame is located above the pivot point at which said upper swivel arm is hinged to said movable frame.

5. The scarifier device according to Claim 4, wherein the distance between the pivot points at which the lower swivel arm is hinged to said fixed and movable frames is greater than the distance between the pivot points at which the upper swivel arm is hinged the said fixed and movable frames.

6. The scarifier device according to Claim 1, wherein said scarifier tool is movable between a first position in which it is at a maximum depth in the ground and a second position in which it is at ground level, said tool defining an angle of incidence, with respect to the ground, said angle of incidence varying by about 5" between said first and second positions.

7. The scarifier device according to Claim 1, wherein said upper swivel arm comprises second fluid operated actuating means.

8. The scarifier device according to Claim 7, wherein said second actuating means comprises a hydraulic cylinder having a piston rod and a casing; said piston rod is hingedly connected to said movable frame and said casing is hingedly connected to said fixed frame.

9. The scarifier device of claim 7, wherein said fluid operated actuating means includes head end chamber means having a cross-sectional area- said second fluid operated actuating means includes rod end chamber means having a cross-sectional area; the area of said head end chamber means of said fluid operated actuating means and the area of said rod end chamber means of said second fluid operated actuating means being substantially equal and effective to move said scarifier tool in a substantially horizontal direction.

10. The scarifier device of Claim 1, wherein said lower swivel arm comprises at least two longitudinally extending members rigidly connected together, and said actuating means extends between each of said members and said movable frame.

11. The scarifier device of Claim 10, wherein said second fluid operated actuating means is disposed between said longitudinally extending members.

12. A hydraulic circuit for operating a scarifier device attached to an earth moving machine including a linkage having a movable frame with a working tool attached thereto, a fixed frame, and upper and lower swivel arms, first fluid operated actuating means extending between said movable frame and said lower swivel arm, said first actuating means having a pair of chambers adapted to admit and discharge fluid, said upper swivel arm including second fluid operated actuating means having a pair of chambers adapted to admit and discharge fluid, said hydraulic circuit comprising: first valve means having a first position wherein hydraulic fluid is delivered to one of said chambers of said second actuating means and discharged from the other of said chambers to selectively adjust the length of the upper swivel arm; saidfirstvalve means having a second position wherein hydraulic fluid is prevented from being delivered to and discharged from said chambers of said second actuating means thereby maintaining the upper swivel arm at said preselected length; second valve means for delivering hydraulic fluid through said first valve means into one of the chambers of said first actuating means and to discharge fluid from the other of said chambers of said first actuating means to selectively adjust the elevation of said scarifier device in a parallelogram movement during which the distance between the hinging points of each of said swivel arms remains constant and the angle of incidence of the tool with respect to the ground has a substantially predetermined value depending upon the preselected length of said second fluid operated actuating means; and said first valve means in said first position delivers the fluid discharged from said second actuating means to one of said chambers of said first actuating means while the fluid is simultaneously discharged from the other of said chambers of said first actuating means such that the angle of incidence of the tool with respect to the ground varies in response to movement of said first actuating means.

13 The hydraulic circuit of Claim 12, wherein said first valve means includes a third position wherein hydraulic fluid is delivered to one of said chambers of said second actuating means and discharged from the other of said chambers and wherein said hydraulic fluid is prevented from being delivered to and discharged from the chambers of said first actuating means.

14. A scarifier device substantially as hereinbefore described with reference to and as shown in the attached drawings.

15. A hydraulic circuit substantially as hereinbefore described with reference to and as shown in the attached drawings.