Earth working apparatus

Abstract: An earth working apparatus has a helical coil (12) rotatable about a horizontal axis by moving the coil over the ground. Cleaning means for cleaning earth from the coil has protruding portions which protrude into the spaces between consecutive turns of the helical coil (12), and which are moveable in a longitudinal direction along the coil to allow for the effective movement of the spaces of the coil along the longitudinal direction during rotation of the helical coil. The cleaning means is a further, smaller diameter, helical cleaning coil (19) which hangs from a central core (15) of the earth working coil (12), and effects cleaning of the coil (12) by protruding into the spaces between the turns of the earth working coil (12).

Description: The present invention relates to an earth working apparatus. A number of forms of apparatus used for earth working include an elongate helical coil mounted on a frame for rotation about the longitudinal axis of the coil relative to the frame. In operation the coil rotates about a substantially horizontal axis by the effect of contact of the earth with the coil when the coil is dragged across the ground, for example by a tractor. The rotation of the coil may be used for example for crumbling the earth to provide a seed bed, or the apparatus may be used as a plough packer for consolidating the land after ploughing, again to provide a seed bed. A difficulty with such coils is that in wet conditions earth clings to the coils, blocking the coils and reducing efficiency of operation. Previously known attempts to clean such a coil have been made by providing a fixed scraper bar parallel to the axis of the coil and positioned close to the periphery of the coil, so as to scrape off excess earth. However such attempts have been unsuccessful in adequately cleaning the helical turns of the coil. US-A-2,300,851 (Wolfard) discloses an earth working apparatus comprising a frame, an elongate earth working rotary member mounted on the frame for rotation about the longitudinal axis of the rotary member in contact with the earth for the purposes of earth working; and means for cleaning the earth working rotary member. In this apparatus, the rotary member is a horizontal cylinder bearing a series of helical grooves about its outer surface. The cleaning means comprise a horizontal array of petalled wheels which mesh with the grooves in the cylinder, and appear to clean the cylinder by the tips of the petals digging dirt out of the grooves in the cylinder. Rotation of the grooved cylinder forces the petalled wheels to rotate by the effect of the grooves on the tips of the petals. Other prior art which discloses means for cleaning earth working implements comprises US-A-396170 (Newson) US-A-2,261,893 (Wolfard) and US-A-1,237,446 (Arce). It is an object of the present invention to provide means for cleaning an elongate helical coil in an earth working apparatus, particularly when operating in wet conditions, when the earth clings to the coil to an extent much greater than is the case with a simple grooved cylinder. According to the present invention earth working apparatus as defined above is characterised in that the earth working rotary member comprises an elongate helical coil, and in that the cleaning means comprises a further elongate helical coil wound in the same direction as the first helical coil, the second helical coil being mounted by hanging from a central core member of the first helical coil inside the first helical coil, and being arranged such that portions of turns of the second helical coil protrude into spaces between the turns of said first helical coil. Preferably the diameter of the second coil relative to the first is such that when hanging freely the lowermost part of the outer periphery of the second coil is substantially level with the lowermost part of the periphery of the first coil. The said central core member of the first helical coil may comprise an axle which is fixed relative to the frame, on which the first coil rotates. Alternatively the central core member may be fixed relative to the first helical coil and may rotate therewith. In a preferred form, the helical cleaning coil has the same pitch as the main helical coil. However, in other arrangements a multiple or a fraction of the pitch of the main helical coil may be used. Although it is possible for the cleaning means to be driven in movement by drive means independent of the main helical coil, it is arranged in preferred forms of the invention that the said protruding portions of the cleaning means are moveable by the effect of contact of the protruding portions with the main helical coil. Thus, it is preferred that the said second helical coil is freely rotatable in itself, and in operation is moved by the effect of contact of turns of the first helical coil on turns of said second coil. It is also preferred that the earth working coil is driven in rotation by the effect of contact with the ground as the coil is moved over the earth. Thus, at least in preferred embodiments of the invention, there may be provided a cleaning system for an earth working coil which is powered entirely by the movement of the earth working helical coil over the ground, and which allows thorough cleaning of the earth working coil by the protrusion of portions of the cleaning rotors into the spaces between the turns of the coil, by a scraping action due to direct contact of the cleaning means against the sides of the turns of the earth working coil. An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:- Figure 1 is a diagrammatic plan view of an earth working apparatus as described in EP-A-0280399; Figure 2 is a view along the direction of movement of the apparatus, of an earth working apparatus embodying the present invention. Figure 1 illustrates an earth working apparatus which is described and claimed in our co-pending application EP-A-0280399. This apparatus is described herein simply for ease and convenience in describing the apparatus of the present invention. The apparatus shown in Figure 1 comprises a frame 11 arranged to be mounted on a vehicle, for example at the rear of a tractor, for movement over the land in the direction A or the direction B as indicated by arrows in Figure 1. The preferred direction of movement is direction A , but the positioning of the moving components is that which would arise for movement in the direction B . A helical coil 12 is mounted by end plates 13 and 14 on a central core 15 which is journalled for rotation about the axis of the coil 12. The coil 12 may be of conventional design, for example a 1.5 inch square steel bar wound along a helix having a pitch of 5.5 inches. In operation the coil 12 is rotated by the effect of the coil being dragged over the ground by the tractor. Mounted on the frame 11 is an array of cleaning rotors 16 each of which is rotatable about a respective bolt 17 by which the rotor is mounted on the frame 11. Each rotor 16 comprises four arms 18 extending outwardly from the bolt 17, but off-set slightly from the radial position, so as to be substantially tangential to the axis of rotation of the rotor. Each rotor 16 is freely rotatable on its bolt 17, and the arms 18 protrude into the spaces between turns of the helical coil 12. In operation, rotation of the helical coil 12 causes the turns of the coil 12 to make contact with the arms 18 of the rotors 16, and the coil is cleaned by the scraping action of the arms 18 on the sides of the turns of the coil 12. As the coil 12 rotates in effect the spaces between the turns of the coil move longitudinally along the coil, and the rotors 16 are rotated by the effect of contact of the turns of the coil 12 on the arms 18. In Figure 2 there is shown earth working apparatus embodying the present invention. As in the apparatus illustrated in Figure 1, the earth working apparatus includes an elongate helical coil 12 mounted by end plates 13 and 14 on a central core 15, which is mounted for rotation on a mobile frame (not shown). The construction of the earth working coil 12 may be the same as has been described with reference to Figure 1. Means for cleaning the coil 12 comprises a further helical coil 19 which is of the same pitch as the earth working coil 12, but of smaller diameter, and which is positioned inside the periphery of the earth working coil 12. The cleaning coil 19 is hung freely from the central core 15 of the coil 12. In operation the rotation of the earth working coil 12 bring the sides of the turns of the coil 12 into scraping contact with the sides of the turns of the cleaning coil 19, and thus effects a cleaning action of the earth working coil 12. The cleaning coil 19 is rotated by the effect of contact with the earth working coil 12. Portions of the cleaning coil 19 protrude into the spaces between the turns of the earth working coil 12, and these protruding portions in effect move longitudinally along the length of the earth working coil 12, to take account of the movement of the turns of the coil 12 along the said longitudinal direction.

Claims: An earth working apparatus comprising a frame (11), an elongate earth working rotary member (12) mounted on the frame (11) for rotation about the longitudinal axis of the rotary member (12) in contact with the earth for the purposes of earth working; and means (19) for cleaning the earth working rotary member (12), characterised in that the earth working rotary member comprises an elongate helical coil (12), and in that the cleaning means comprises a further elongate helical coil (19) wound in the same direction as the first helical coil (12), the second helical coil (19) being mounted by hanging from a central core member (15) of the first helical coil (12) inside the first helical coil (12), and being arranged such that portions of turns of the second helical coil (19) protrude into spaces between the turns of said first helical coil (12). Apparatus according to Claim 1, wherein the diameter of said second coil (19) relative to the first coil (12) is such that when hanging freely the lowermost part of the outer periphery of the second coil (19) is substantially level with the lowermost part of the periphery of the first coil (12). Apparatus according to Claim 1 or 2, in which the pitch of the second coil (19) is the same as the pitch of said first coil (12). Apparatus according to any preceding claim, in which the said central core member (15) of the first helical coil (12) comprises an axle (15) which is fixed relative to the frame, on which the first coil rotates. Apparatus according to any of Claims 1 to 3, in which the central core member (15) is fixed relative to the first helical coil (12) and rotates therewith. Apparatus according to any preceding claim, in which said second helical coil is freely rotatable in itself, an in operation is moved by the effect of contact of turns of the first helical coil on turns of said second coil.

Inventors: BRADLEY JOHN, BRADLEY, JOHN
Applicants: FLEXI COIL LTD, FLEXI-COIL (UK) LIMITED
Application year: 1991
Main classification: A01B29
IPC codes: A01B29