AU2003288315B2

AU2003288315B2 - Precision disc tiller and safety device therefor

Info

Publication number: AU2003288315B2
Application number: AU2003288315A
Authority: AU
Inventors: Michel Evin
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-10-14
Filing date: 2003-10-13
Publication date: 2009-05-28
Anticipated expiration: 2023-10-13
Also published as: FR2845560B1; JP4828123B2; AU2003288315A1; JP2006502725A; PL376370A1; EA200500460A1; WO2004034768A1; FR2845560A1; ES2291719T3; EP1551213A1; KR101083875B1; OA12944A; BR0315294A; RS20050295A; CA2501338C; UA81263C2; CN100397969C; LT2005036A; KR20050074482A; CN1705435A

Abstract

The disk pulveriser has non-motorized disks (3), each of which is mounted on a spiral spring (5) with at least one-and-a-half turns whose other end is attached to the machine frame (2). The turns of the spring lock together when the pressure on the disk exceeds a threshold value, allowing the disk to rise when released. An Independent claim is included for a safety system for the pulveriser.

Description

WO 204/034768 1 PCT/FR2003/0030091 PRECISION DISC TILLER AND SAFETY DEVICE FOR SUCH A DISC TILLER This invention concerns a precision disc tiller of the type comprising an integrally-mounted or trailed frame equipped with ploughing implements consisting of at least one set of non-driving rotating ploughing discs, the discs working in the soil according to a working depth adjustable preferably by means of at least one reference device, such as a skid, wheel or roller connected to the said frame and being mounted independently and swivelling respectively with regard to the carrier frame through a safety device which, when the load exerted on the disc is greater than a predetermined load, allows a vertical retraction of the disc and below the said load allows return of the disc to the working position, thus acting as a safety device for a disc tiller of the type mentioned above. These days disc tillers are well-known to those expert in the art. The disc tillers are usually comprised of a carrier frame with one or more disc sets. Each disc or group of discs can be connected to the frame according to essentially two methods. The first method consists in mounting the discs permanently on the frame. The discs may however be connected to the frame so as to be capable of pivoting about a vertical axis which allows alignment of the discs with regard to the axis of forward motion of the frame. Such is the case described in particular in the patents US-A-2.659.291 and US-A-2.768.864. Nonetheless, the lack of capability of disc withdrawal creates several drawbacks, namely lack of precision in particular of the work carried out by the disc tiller on account of when a disc encounters an obstacle, it results in a partial raising of the frame so that some of the other discs are no longer able to work. In the same way, the lack WO 204/034768 2 PCTIFR2003/0030092 of withdrawal of a disc when it encounters an obstacle can produce premature wear of the disc, or even breakage of the disc. For this reason, rigid mounting of the disc relative to the carrier frame does not allow the design of a precision disc tiller capable of working at specific depths and at high speeds, so much so that such a disc tiller cannot include sowing devices either, like those which have appeared in the last few years on this type of machine. To resolve these problems, there has therefore appeared recently on the market, particularly through the French patent application FR-A-2.813.749, disc tillers of the type comprising an integrally-mounted or trailed frame equipped with ploughing implements consisting ofat least one set of non-driving, rotating ploughing discs, each ploughing disc being mounted independently and swivelling with regard to the carrier frame of the disc tiller in such a way as to yield at an adjustable predetermined load. In that previous patent application, each ploughing disc is connected to the frame through a linkage device, such as an arm mounted on the said frame and swivelling about an axis more or less parallel to the axis of rotation of the ploughing disc, the said arm co-operating with a pre-tensioned component so as to allow swivelling of the arm in the direction of a retraction of the disc by raising it only when the load exerted on the disc becomes greater than the rated load of the pre-tensioned component. Return to the working position is carried out automatically under the dual prompting of the reaction of the pre-tensioned component and the weight of the disc. In the case of an obstacle to be cleared by one of the discs, such a solution avoids the raising of the whole of the frame carrying the discs. The result is an improved working ofthe soil and constant depth. Nevertheless, since such machines are equipped with a large number of discs, the complexity of the device, which necessitates both the presence of a rigid arm and a pre-tensioned component, makes the machine complicated and costly. Furthermore, the large number of discs results in an extremely small distance between the discs.

WO 204/034768 3 PCT/FR2003/0030093 It is therefore necessary to have an extremely short connecting shaft from the disc carrier arm to the support piece. It can result in rapid and premature wear of such devices. In other respects, the discs have a tendency to exert a lateral load in the soil, thereby tending to increase the wear. Furthermore, through Patents US-A-3.640.348 and US-A-2.750.861, agricultural machines are known which comprise a disc coupled to the carrier frame of the said machine by means of a spring. In the case of Patent US-A-2.750.861, the disc is an opener disc of a sowing machine intended for plowing a furrow. The disc is fitted with a U-shaped shackle which is connected to the carrier frame through a leaf spring. The spring, on account of it being a leaf spring, is forced to form a U-shape in order to avoid any lateral oscillation of the disc. Therefore this results in a cumbersome and costly solution on account of the presence of the shackle. Conversely, the presence of the shackle prevents any lateral withdrawal or release of the disc in the event of encountering an obstacle. In the case of Patent US-A-3.640.348, which applies more particularly to the "covercrop" type machines where all of the discs are mounted on the same support beam, each disc is connected to the support beam by an S-shaped leaf spring. Again, either there is no provision for control of the disc and a continuous lateral oscillation of the disc is seen, or it is necessary to boost the lateral stability of the disc by an appropriate position-holding component at the risk of increasing both the weight and cost of such an installation. Finally, in another field of application, the combination of a disc designed to carry out a marking out operation in the soil and a spiral spring in the shape of a question mark, is known through Patent FR-A-2.658.979. The embodiment of a spiral spring makes it impossible to avoid the lateral displacement of the disc.

4 Object of the Invention It is the object of the present invention to substantially overcome or ameliorate one or more of the disadvantages of the prior art, or to provide a useful alternative. Summary of the Invention 5 The present invention at least in a preferred embodiment provides a precision disc tiller whose discs are connected to the carrier frame by a device which permits an independent and swivelling mounting of the discs relative to the carrier frame while allowing a reduction in the wear of the connecting components of such a device, and to simplify the design of such a device. 10 The present invention at least in a preferred embodiment is directed to a precision disc tiller in which the design of safety devices permits the mounting of a large number of discs for an unchanged overall width of the machine because of the small space requirement of such devices. The present invention at least in an embodiment is directed to a precision disc 15 tiller whose design of safety devices permits release of the discs following a vertical withdrawal or following a lateral withdrawal so that the safety device can be considered capable of working in three dimensions. The present invention at least in an embodiment is directed to put forward a precision disc tiller whose design of safety devices permits it, due to the asymmetric 20 nature of the devices, to respond fully to the forces of the ploughing discs which have at least one cutting angle and generally one penetration angle and which are therefore, for these reasons, subject to asymmetrical lateral stresses fully controlled by the asymmetric nature of the safety devices. The present invention in a first aspect provides a precision disc tiller of the type 25 which comprises an integrally-mounted or trailed frame equipped with ploughing implements consisting of at least one set of non-driving rotating ploughing discs, the discs having at least one cutting angle and being mounted respectively independently and swivelling relative to the carrier frame through a safety device which permits, when the pressure exerted on the disc is greater than a predetermined pressure, a vertical 30 withdrawal of the disc and below the said pressure permits return of the disc to the working position, wherein each ploughing disc is a concave disc connected to the frame 5 by a helical spring forming at least one turn, so as to create at the spring an overlapping zone, one end of the spring being coupled directly, or through a connection piece, to the frame while the other end of the spring is coupled to the hub of the disc and is arranged on the concave side of the disc, the spring being positioned in such a way that the turn(s) 5 of the said spring are contracted by coiling up when the pressure exerted on the disc is greater than the predetermined pressure, allowing a vertical retraction of the disc by lifting. Preferably the helical spring forms at least one and a half turn so as to create at the spring an overlapping zone. 10 Thanks to the design of the safety device formed by a simple helical spring, the disc can move in three dimensions. Consequently the result is the possibility for the disc to slip away from an obstacle by vertical and/or lateral withdrawal. Furthermore, by acting on the section of the elements being used to form the turns of the spring and/or by acting on the number of turns and/or the kind of constituent material of the elements, it Is becomes easy to define accurately the reactions of the spring so as to avoid a untimely drumming of the discs and to limit the permitted lateral displacement of the discs. Thus with a component of extremely simple design, the same is preferably obtained as those obtained using a pivoting arm fitted with a pre-tensioned component and whose wear can be limited and reduced over time as a result of the removal of any articulated part of the 20 swivel pin type. According to a preferred form of implementation of the invention, each ploughing disc has at least one cutting angle and preferably one penetration angle causing application of generally oblique, lateral forces on the disc during forward movement of the frame and in that the flanks of the turn(s) of the helical spring are arranged relative to 25 the disc by tending to draw closer to each other under the action of the lateral force so as to limit the effect of this lateral force. In other words, the lateral force exerted by the disc tends to cause a coiling up of the turn(s) which results in a contraction of the turn(s) as far as a limit stop position. In another aspect of the present invention there is also provided a safety device 30 for a disc tiller of the type comprising a integrally-mounted or trailed frame equipped with ploughing implements consisting of at least one set of non-driving rotating 6 ploughing discs, the discs working in the soil according to a working depth adjustable preferably by means of at least one reference device, such as a skid, wheel or roller connected to the said frame and being mounted independently and swivelling respectively with regard to the carrier frame, the safety device being capable of insertion between the s frame and a disc so as to allow, when the pressure exerted on the disc is greater than a predetermined pressure, a vertical withdrawal of the disc and below the said pressure a return of the disc to a working position, wherein the disc consists of a helical spring formed from at least one and a half turns, the spring having a first end capable of connection directly or through a linking piece to the frame and a second end capable of to connection to the hub of the disc, the spring being positioned, in the mounted condition on the device, in such a way that, when the pressure exerted on the disc is greater than the predetermined pressure, the turn(s) of the said spring contract by coiling up, permitting a vertical retraction of the tool by lifting. Brief Description of the Drawings 15 Preferred embodiments of the present invention will now be described, by way of examples only, with reference to the accompanying drawings wherein: Figure 1 shows a partially perspective top view of a disc tiller in accordance with an embodiment of the invention; Figure 2 shows a 3/4 rear view of a safety device extending between the carrier 20 frame and a disc; Figure 3 shows a front view of the safety device in Figure 2; Figure 4 shows a side view of the safety device in Figure 2; and Figure 5 shows a partial perspective side view of the safety device in Figure 2. Detailed Description of the Drawings 25 As mentioned above, the precision disc tiller, subject of the invention, comprises a integrally-mounted or trailed frame 2 equipped with ploughing implements 3. The frame 2 can assume a large number of shapes. In the example shown, the frame 2 is comprised of a framework made of two girders linked together by crosspieces made up of beams equipped with ploughing implements. These beams extend more or less 30 perpendicularly to the traction line of the frame 2. The frame 2 is moreover fitted with a 7 drawbar hitch for attachment to a towing vehicle. The hitch will be preferably of the three point type. The ploughing implements are comprised of at least one set of non driving rotating ploughing discs. The set of discs 3 extend along a working width, that is to say along a line perpendicular to the line of traction of the frame 2. It should be noted 5 that "non-driving ploughing disc" is understood to mean ploughing discs whose rotational drive is produced under the effect of the fictional force with the soil, a force generated by the movement of the towed frame. The discs 3 work in the soil according to a working depth adjustable preferably by means of at least one reference device 4, such as a skid, wheel or roller connected to the frame 2. Preferably the reference device 4 is common to i0 at least three ploughing discs 3, preferably at least five ploughing discs 3 so as to guarantee an adequate control of working depth. In the examples shown, the working depth control device 4 is constituted by a cage drum roller common to the set of ploughing discs of the rear set of the disc tiller. The cage WO 204/034768 8 PCT/FR2003/0030098 drum roller 4 is coupled to the frame 2 by two arms extending to the rear of the framework forming the frame, the said arms being adjustable in position on the frame 2. The adjustment of working depth is carried out through co-operation of the reference device with the drawbar hitch. The adjustment could, in the same way, be made also by the drawbar hitch alone. The ploughing implements formed by the non-driving rotating ploughing discs 3 are designed such that each ploughing disc 3 is mounted independently and swivelling relative to the carrier frame 2 of the disc tiller so as to retract under an adjustable predetermined pressure and thus achieve work in the soil at constant depth of the ploughing discs 3. Each disc 3 is in this way joined to the frame 2 by a helical spring 6 forming at least one turn, preferably at least one and a half turns. One end 6A of the spring 6 can be coupled directly, or through a linking piece 7, to the frame 2 while the other end 6B of the spring 6 can be coupled directly, or through a linking piece, to the hub of the disc 3. The spring 6 is positioned in such a way that when the pressure exerted on the disc 3 is greater than the predetermined pressure, the turn(s) of the spring contract by coiling up, permitting a vertical retraction of the disc 3 by lifting. In the examples shown, each ploughing disc 3 is a concave disc, preferably of large diameter. In fact, the diameter is usually greater than 48 cm and preferably at least 51 cm. The end 6B of the spring 6 connected to the hub 8 is situated on the concave face of the disc 3. This arrangement has a certain number of advantages. It permits first of all a reduction in the space required for the spring/disc assembly with a view to increasing the number of discs on the same disc tiller without altering the overall width of the assembly. It also permits the arrangement of a support for the spring 6 extending in line with the disc's point of penetration into the soil, which results in better working of the soil.

WO 204/034768 9 PCT/IFR2003/0030099 Accordingly the end 6B of the spring is connected to the part of the hub 8 extending to the concave face of the disc 3 and is positioned in the vicinity of the concave face of the disc 3. That is to say, on the opposite side from the free end of the said hub 8. The hub 8 is generally coupled at that end to a plate mounted free-rotating relative to the said hub 8, the concave face of the disc 3 being bolted onto the plate. Furthermore this arrangement, with the aid of the disc, enables the disc to be protected. Each ploughing disc 3 generally has a positive penetration angle in the range [3 - 20] degrees, and a positive cutting angle in the range [10 - 30] degrees. Each ploughing disc 3 is again preferably toothed on its periphery. The teeth are represented by 9 in the figures. The fact that each ploughing disc 3 has at least one cutting angle and preferably one penetration angle in order to fulfil its ploughing function results in the action, linked to the presence of these angles, of generally oblique lateral forces R which tend to want to straighten the disc and line it up again during the movement of the disc in the soil. To limit the effect of these lateral forces and to prevent in particular too large a lateral withdrawal of the disc, the turn(s) of the helical spring are arranged in relation to the disc and coiled up in a direction in which the flanks ofthe turn(s) draw closer together (Direction D Figure 5) under the action of the lateral force R so as to limit the action of this lateral force particularly once the flanks are abutting each other. To achieve this result, the spring has to be wound up helicoidally and non-spirally because at least one zone of partial overlapping or covering on a turn or between the turns is necessary so as to form an axial stop with regard to the lateral forces exerted by the disc. The action of these various forces is more particularly obvious in Figure 5 which represents schematically the lateral forces R exerted on the disc and the resultant D at the level of the turns of the spring. It will be noted that the force exerted D extends from the section of the spring connected to the disc towards the section of the spring connected to the frame which forms a limit stop. To complete the action of the helical spring and its co-operation with the discs, preferably the flanks of the turn(s) rest in contact WO 204/034768 10 PCT/FR2003/00300910 against each other, including in the inoperative position of the spring. Thus it may be noted that the safety device obtained by means ofthe helical spring is an asymmetric type safety device which perfectly suits the work of the ploughing disc, which is itself subject to asymmetric forces during its operation. Thus the helical spring co-operates with the disc to withstand the lateral forces to which the disc is subjected during the movement of the frame, while permitting a lateral displacement of the disc in the event of encountering an obstacle. In the examples shown, taken in the direction of forward movement of the frame, the disc tiller comprises at least two, more or less parallel, successive sets 3A, 3B of ploughing discs 3, the ploughing discs 3 constituted by concave discs having a concavity in one set of discs laterally reversed to another set of discs. This results in the necessity to provide springs coiling up for example to the left for the front disc set and to the right for the rear disc set. The end 6A of the spring 6 solidly fixed to the frame 2 is generally connected to a plate 7 by clamping to a transverse beam of the frame as Figures 2 and 3 particularly illustrate. The clamping is made for example by means of bolts and a plate extending parallel to the plate 7 carrying the end 6A of the spring. As regards the other end 6B of the spring 6, it is attached by welding to the hub 8 of the disc 3. It is possible to envisage other methods of attachment. Thus the end 6A of the spring 6 can happen to be housed in a sleeve, itself fixed to the frame 2. Each spring 6 consists of from one and a half to five turns, the said turns being arranged side by side so as to form an alignment of turns along a line transverse to the frame 2. This arrangement of turns also permits the lateral rigidity ofthe assembly to be adjusted at will. The last turn of each spring 6 is prolonged so as to form a start of a tangential section, these sections 6C extending as far as the hub 8 of the disc 3 while forming an arc of a circle with the concavity turned towards WO 204/034768 11 PCT/FR2003/00300911 the soil as illustrated in particular in Figures 2 and 4. This curving of the section 6C makes it possible to prevent jamming of debris between the section 6C and the disc 3. In fact, on account of the particular shape of the section 6C of the spring 6 and in particular the penetration and cutting angles ofthe disc 3, a maximum clearance results between the disc 3 and section 6C at this level, hence a reduction in the risk of filling-up or clogging the space between section 6C and concave face of the disc 3. In the examples shown, each turn of the spring 6 is formed by winding a square-section wire although the wire can be of any cross-section. The spring 6 is preferably made by deforming a wire of cross-sectional area in the range [650 mm 2 - 2600 mm 2 ] for a disc diameter in the range [480 mm - 700 mm]. Thus the disc tiller described above includes as many safety devices, constituted by the said springs, as there are discs. The design of the safety device, greatly simplified in comparison with the prior art, makes it possible to obtain a machine of simple design with reduced wear which accomplishes precision ploughing, that is to say at a more or less constant depth and at particularly high speeds of the order of 10 to 30 km/hour.

Claims

1. A precision disc tiller of the type which comprises an integrally mounted or trailed frame equipped with ploughing implements consisting of at least one set of non-driving rotating ploughing discs, the discs having at least one cutting angle and 5 being mounted respectively independently and swivelling relative to the carrier frame through a safety device which permits, when the pressure exerted on the disc is greater than a predetermined pressure, a vertical withdrawal of the disc and below the said pressure permits return of the disc to the working position, wherein each ploughing disc is a concave disc connected to the frame by a helical spring forming at least one turn, so as io to create at the spring an overlapping zone, one end of the spring being coupled directly, or through a connection piece, to the frame while the other end of the spring is coupled to the hub of the disc and is arranged on the concave side of the disc, the spring being positioned in such a way that the turn(s) of the said spring are contracted by coiling up when the pressure exerted on the disc is greater than the predetermined pressure, allowing is a vertical retraction of the disc by lifting.

2. The disc tiller according to Claim 1, wherein said disc tiller includes, taken in the direction of forward movement of the frame, at least two, more or less parallel, successive sets of ploughing discs, the ploughing discs comprised of concave discs having a concavity in one set of discs laterally reversed to another set of discs. 20

3. The disc tiller according to either one of Claims I and 2, whereby each ploughing disc has at least one cutting angle and one penetration angle causing application of generally oblique, lateral forces on the disc during forward movement of the frame and in that the flanks of the turn(s) of the helical spring are arranged relative to the disc by tending to draw closer to each other under the action of the lateral force so as 25 to limit the effect of this lateral force.

4. The disc tiller according to any one of Claims I to 3, wherein the end of the spring solidly attached to the frame is connected to a plate fixed by clamping to a transverse beam of the frame.

5. The disc tiller according to any one of Claims I to 4, whereby each 30 spring consists of from one and a half to five turns, the said turns being arranged side by side so as to form an alignment of turns along a line transverse to the frame.

6. The disc tiller according to Claim 5, wherein the flanks of the turn(s) of each spring are abutting each other.

7. The disc tiller according to any one of Claims I to 6, wherein the last 35 turn of each spring is prolonged so as to form a start of a tangential section, this section 13 extending as far as the hub of the disc while forming an arc of a circle with the concavity turned towards the soil.

8. The disc tiller according to any one of Claims I to 7, whereby each turn of the spring is formed by winding a square-section wire. 5

9. The disc tiller according to any one of Claims I to 8, wherein the spring is formed by helically winding a wire of cross-sectional area in the range of 650 mm2 to 2600 mm 2 for a disc diameter in the range of 480 mm to 700 mm.

10. A precision disc tiller substantially as hereinbefore described with reference to Figures 1 to 5 of the accompanying drawings. 10 Dated 20 April, 2009 Michel Evin Patent Attorneys for the Applicant/Nominated Person SPRUSON & FERGUSON