Rotating spreader disc with removable vanes for spreading flowable material

Abstract: In a spreader disc consisting of a carrier disc (1), of which only the part closest to the edge is shown, and secured to said disc a number of spreader vanes (2) comprising holding studs (9,10), the heads (7,8) of which can be inserted through apertures (4,5) and then displaced to engage the lower side of the carrier disc (1), after which the spreader vane (2) is secured in position by creating frictional engagement with the carrier disc (1), the main novel feature consists in that the securing means comprise a pressure arm (16) with a cam-shaped surface (17,18,19) and being pivotably supported on the spreader vane (2) and cooperating with the opposing surface on the carrier disc (1) to form a dead-center mechanism, so that the pressure arm (16) can be turned to a locking position (E), in which it is in stable abutment against the upper side of the carrier disc (1), the spreader vane (2) and/or the carrier disc (1) yielding elastically in the region under load and hence providing the requisite force for creating the frictional engagement between the spreader vane (2) and the carrier disc (1). In this manner, the risk of losing securing means in the form of e.g. wing nuts is avoided, while at the same time the force, with which the frictional engagement is maintained, is constant and in particular does not depend on the strength of the operator's fingers.

Description: TECHNICAL FIELD The present invention relates to a rotating spreader disc for spreading flowable material, said spreader disc being of the kind set forth in the preamble of claim 1. BACKGROUND ART A spreader disc of the kind referred to above is known from the German published specification No. DE-A-3.919.396, see especially Figures 5-7 with the associated text. In the spreader disc thus known, the securing member consists of a bolt with an attached wing nut, said wing nut to be loosened or tightened respectively, when the vane is to be removed or secured respectively. This known arrangement suffers from three substantial disadvantages, viz. firstly, that relatively long time is needed to loosen and tighten the wing nut, secondly, that the bolt with the wing nut is not protected against screwing-off of the wing nut, so that the latter, possibly also the bolt, is released and may fall down on the field, where these parts are not always easy to recover, and thirdly, that the force, with which the securing member - i.e. the bolt and the wing nut - keeps the spreader vane in question in engagement against the carrier disc, depends on the the force with which the user concerned has tightened the wing nut. It is well-known from various areas of technology to use so-called over-centre mechanisms for easy securing and easy freeing of attachments. One example of the use of an over-centre mechanism is disclosed in FR-A-2,659,400, and other well-known uses are ski bindings and closures for jars used in households for preserving foods, as well as quick-coupling arrangements of various kinds. DISCLOSURE OF THE INVENTION It is on this background the object of the present invention to provide a spreader disc of the kind referred to initially, that does not suffer from the disadvantages referred to above, by utilizing the principles of the over-centre mechanisms referred to above, and this object is achieved with a spreader disc, according to the present invention additionally exhibiting the features set forth in the characterizing clause of claim 1. By means of these features, the following advantages are achieved, cf. the above: firstly, quick and easy securing of the spreader vane to the carrier disc, as well as equally quick and easy removal without the use of tools, secondly, there are no nuts or screws likely to get lost, and thirdly a constant holding force is achieved. Further embodiments of the spreader disc according to the invention, the effects of which - beyond what is self-evident - will also be explained below, are set forth in claims 2-6. BRIEF DESCRIPTION OF THE DRAWINGS In the following detailed portion of the present description, the invention will be explained in more detail with reference to the exemplary embodiment of a rotating spreader disc with removable vanes according to the present invention shown on the drawing, on which Figure 1 shows the spreader disc seen from above with one of the two spreader vanes removed, Figure 2 at an enlarged scale shows the spreader vane shown in Figure 1, as viewed in the direction of the arrow II in Figure 1 with a pressure arm in an initial abutment position, Figure 3 is a view corresponding to Figure 2, but shows the pressure arm in the locking position, Figures 4 and 5 at the same scale as in Figures 2 and 3 show a spreader vane by itself, viewed in the direction of the arrow IV in Figure 5 and the arrow V in Figure 4 respectively, Figure 6 is a view corresponding to Figure 3 and showing a modified embodiment with a pressure shoe for protecting the surface of a carrier disc, Figure 7 shows the pressure shoe shown in Figure 6 in perspective, and Figure 8 is a view corresponding to Figure 5 of the modified embodiment. DESCRIPTION OF THE PREFERRED EMBODIMENT The spreader disc shown diagrammatically in Figure 1 consists in a manner known in principle of a plane or disc-shaped carrier disc 1, to which a number of spreader vanes 2 - in the present example two - of which only one is shown, is secured in a detachable and adjustable manner. Together with the spreader vanes 2, the carrier disc 1 is intended to rotate in the direction shown by an arrow 3, thus spreading flowable solid material, e.g. artificial fertilizer, from above falling down on to the generally horizontal carrier disc 1, and by the latter and by the spreader vanes 2 being spread outwardly laterally. With a view to securing the spreader vanes 2 detachably and adjustably to the carrier disc 1, the latter comprises in a known manner two securing apertures for each spreader vane, viz. a keyhole-like opening 4, in the following designated as the keyhole slot, as well as a toothed slot 5. Both apertures 4 and 5 have a widened part 6 large enough to allow passage of heads 7 and 8 respectively on holding studs 9 and 10 respectively, whilst apart from this, the apertures 4 and 5 are only large enough to accommodate the stems 11 and 12 respectively of the holding studs concerned. As will be evident from Figures 2-5, the holding studs 8 and 9 are secured to the lower side of the horizontal branch 13 of the spreader vane 2 in question, the vertical branch 14 of which on its outward side, i.e. the side facing away from the horizontal branch 13, is provided with a pivot stud 15, the axis of which is substantially parallel to the horizontal branch 13, cf. Figure 5. On the pivot stud 15 is pivotably supported a pressure arm 16, shaped and placed in such a manner, that it, together with the carrier disc 1 and the spreader vane 2, forms an over-center mechanism for releasably securing each spreader vane 2 to the carrier disc 1. The functioning of the pressure arm 16 can best be explained with reference to Figures 2 and 3. After the spreader vane 2 in question has been placed in the position shown in Figure 2, i.e. when the heads 7 and 8 on the holding studs 9 and 10 respectively have been inserted through the widened part 6 of the keyhole slot 4 and the toothed slot 5 respectively and displaced radially outwardly (i.e. towards the right in Figure 2), the pressure arms 16 is turned from an initial position, in which it is generally perpendicular to the carrier disc 1, through a first angular movement A to the abutment position shown in full lines in Figure 2, in which it abuts against the upper side of the carrier disc 1 with an initial part of a first pressure surface 17. From the position shown in full lines in Figure 2, the pressure arm 16 is then moved through a second angular movement B, while the radius from the axis of the pivot stud 15 to the first pressure surface 17 increases, until the pressure arm 16 has reached a dead-center position C, in which the radius of the first pressure surface 17 is at a maximum, and where the first pressure surface 17 continues in a second pressure surface 18, the radius of which from this point decreases towards the transition to a third pressure surface 19. Obviously, the movement past the abutment position shown in full lines in Figure 2 can only take place, because the carrier disc 1 and/or the spreader vane 2 can be deflected elastically in the parts being acted upon during this movement. This deflection is, however, not shown in the drawing. In the dead-center position C, the transition point between the first and second pressure surfaces 17 and 18 respectively will abut against the carrier disc 1, whilst during a further angular movement, viz. a third angular movement D, the point of abutment is moved along the second pressure surface 18 while the latter's radius decreases, and the spreader vane 2, which during the second angular movement B towards the dead-center position has been urged to a maximum extent away from the carrier disc 1, again approaches the latter, but, due to its own elasticity and/or that of the carrier disc, still maintains the heads 7 and 8 on the holding studs 9 and 10 respectively in abutment against the lower side of the carrier disc 1, in a manner to be seen from Figure 3. Since the radius from the axis of the pivot stud 15 to the third pressure surface 19 varies through a minimum - the pressure surface 19 is substantially flat - the pressure arm 16 will, after completing the third angular movement D and taking up the locking position E shown in Figure 3, remain stably in the locking position, in which it is held by the springiness in the spreader vane 2 and/or the carrier disc 1, at the same time as the heads 7 and 8 are held in abutment against the lower side of the carrier disc 1, hence creating a sufficient frictional engagement to prevent the spreader vane 2 from leaving the operating position, in which it has been placed. Since the force, with which the heads 7 and 8 are held in abutment against the lower side of the carrier disc 1, depends solely on the elasticity of those parts of the spreader vane 2 and/or the carrier disc 1 yielding elastically during the movement of the pressure arm seen from the abutment position shown in Figure 2 to the locking position E shown in Figure 3 and the resulting movement of the center of the pivot stud 15 from the position shown in Figure 2, in which the initial part of the first pressure surface 17 abuts against the carrier disc 1, to the locking position E shown in Figure 3, in which the third pressure surface 19 abuts against the carrier disc and hence creates a constant distance between the center of the pivot stud 15 and the upper side of the carrier disc 1, this friction-creating force will always be of the same magnitude, and is thus independent of the strength of the operator's fingers. When the frictional engagement between the spreader vane 2 and the carrier disc 1 is to be released, this is done quite simply by turning the pressure arm 16 back to the initial position indicated in Figure 2, after which the spreader vane may be removed or adjusted in a different angle in a manner known per se by moving the spreader vane 2 slightly inwardly against the center of the carrier disc and turning it about the aperture 4 to the desired angular position, upon which it is again moved radially outwardly, so that the holding stud 10 engages the corresponding notch in the toothed slot 5. When the spreader vane has been placed in the new position, the pressure arm 16 is again turned towards the locking position as explained above. As will be seen from Figures 1 and 3, the pressure arm 16 will in the locking position E protrude to such an extent beyond the circumference of the carrier disc 1, that the pressure arm in this position easily may be urged away from the locking position by pushing its freely protruding end upwards. In the embodiment shown in Figures 6-8, a U-shaped pressure shoe 20, the bottom part or connecting part of which constitutes a pressure sole 21, is placed about the part of the pressure arm 16 surrounding the pivot stud 15. By means of long holes 23 in the two U-branches, the pressure shoe 20 is supported on the pivot stud 15 in such a manner, that it can be displaced through a small distance in the longitudinal direction of the long holes, but only to a limited extent in their transverse direction. When the pressure arm 16 is moved to the locking position shown in Figure 6, corresponding to the locking position E in Figure 3, the chain of events will be the same as explained above with reference to Figures 1-5, the sole exception being that the pressure sole 21 constitutes an intermediate layer between the pressure arm 16 and the carrier disc 1. Since the pressure shoe 20 cannot be moved to any extent of importance parallel to the surface of the carrier disc 1, this surface will not be subjected to that rubbing or chafing, to which it will be subjected in the exemplary embodiment shown in Figures 1-5, and which in the worst case can cause wear on the carrier disc. If, as a consequence of this rubbing or chafing, the pressure shoe 20 is worn down before the remainder of the spreader vane 2 is due to be replaced, it can easily be replaced by removing the pivot stud 15, to this purpose possibly having a thread (not shown). A recess 22, the bottom of which lies in continuation of the pressure surface, and the depth and length of which correspond to the thickness and the length of the pressure sole 21, allows the pressure arm 16 to abut against the carrier disc 1 with the remainder of the surface in question. In this manner, it is avoided that e.g. particles of fertilizer can get jammed between the pressure arm and the carrier disc. A further advantage being achieved, so to speak at no extra cost, with the exemplary embodiment shown consists in that the pressure arm 16 in the locking position E shown in Figure 3 acts as a steadying brace for the spreader vane 2 when the latter during the rotation impinges against the material to be spread. According to an embodiment not shown in the drawing, the mechanism for pulling the stud heads 7 and 8 into abutment with the carrier disc 1 is replaced by a so-called knee-joint or toggle mechanism. Such mechanisms are widely known, and a skilled person will be able to adapt them to the present use without other guidance than that provided by the present description. LIST OF PARTS 1 carrier disc 2 spreader vane 3 arrow 4 keyhole slot 5 toothed slot 6 widened part 7 head 8 head 9 holding stud 10 holding stud 11 stem 12 stem 13 horizontal branch 14 vertical branch 15 pivot stud 16 pressure arm 17 first pressure surface (part) 18 second pressure surface (part) 19 third pressure surface (part) 20 pressure shoe 21 pressure sole 22 recess 23 long holes A first angular movement B second angular movement C dead-center position D third angular movement E locking position

Claims: Rotating spreader disc for spreading flowable material and of the kind comprising a) a plane or dish-shaped carrier disc (1), and b) at least one spreader vane (2), releasably secured to one side of the carrier disc (1) by means of c) releasable securing means (4,5,9,10) comprising c1) in the carrier disc (1) at least one aperture (4,5), c2) on each spreader vane (2) at least one holding stud (9,10), the stem (11,12) of which has a smaller cross-sectional dimension than its head (7,8), that is small enough to be able to pass through said aperture (4,5) in at least one position relative to the aperture, and c3) at least one manually operable securing mechanism (15-19) adapted to secure each spreader vane (2) relative to the carrier disc (1) by pulling said head (7,8) against the opposite side of said disc (1) so as to form a frictional engagement preventing each spreader vane from moving relative to the carrier disc from the position, in which the securing means were actuated, characterized in d) that each securing mechanism (15-19) comprises an over-center mechanism adapted to during movement of a manoeuvering member (16) in one and the same direction for the purpose of said securing d1) in a first part-movement (A+B) to urge the spreader vane (2) in a direction away from the carrier disc (1) so as to make the heads (7,8) of the holding studs (9,10) abut against the opposite side of the carrier disc and then to urge the spreader vane (2) in the same direction away from the carrier disc (1) under elastic deflection of those parts of the carrier disc (1) and/or the spreader vane (2) hereby being subjected to a load, said first part-movement (A+B) ending at the dead-center position (C), and d2) in a second part-movement (D) to allow movement of said parts of the carrier disc (1) and/or the spreader vane (2), that have been subjected to a load during said second part-movement (A+B), in the opposite direction of the first part-movement (A+B), but to a somewhat shorter extent, so that after the end of the second part-movement (D), a part of said elastic deflection will be retained, the second part-movement (D) ending in a locking position (E), in which the manoeuvering member (16) is held by the elastic force being exerted by said parts being under load, e) that the spreader vanes (2) and/or the carrier disc (1) as well as the manoeuvering member (16) are shaped and dimensioned in such a manner, that said elastic deflection may be produced by manual operation of the manoeuvering member, and that the elastic force exerted by said parts under load in said locking position (E) of the manoeuvering member (16) is sufficient to produce the requisite friction between the carrier disc (1) and each spreader vane (2) to provide the frictional engagement mentioned (in item c3 above), and f) that the manoeuvering member (16) has such a length and is placed in such a manner, that in the locking position (E) it protrudes outside of the circumference of the carrier disc (1). Spreader disc according to claim 1, characterized in that each securing mechanism (15-19) comprises a pressure arm (16) pivotably supported about a stud (15) extending substantially parallel to the surface of the carrier disc (1) and secured to the spreader vane (2), said pressure arm comprising a pressure surface extending about the stud (15) and comprising at least three parts (17,18,19) placed in sequence, viz. a first part (17), the greatest radial distance of which from the axis of the stud (15) corresponds to the distance between the axis of the stud and an opposing pressure surface on the carrier disc (1), when the heads (7,8) of the holding studs (9,10) are in light abutment against the opposite side of the carrier disc (1), a second part (18) the radial distance of which from the axis of the stud (15) is greater than the greatest radial distance therefrom of said first part (17), and a third part (19), the least radial distance of which from the axis of the stud (15) is greater than the greatest radial distance of said first part (17) therefrom, but less than the greatest radial distance of said second part (18) therefrom. Spreader disc according to claim 1 or 2 and of the kind, on which each spreader vane (2) is shaped generally like a piece of angle iron, one branch (13) of which during operation abuts against the carrier disc (1), and the second branch (14) during operation engages flowable material supplied from above and throws it out sideways, characterized in a) that the holding studs (9,10) or the apertures are placed on or shaped in said one branch (13) at a distance from said second branch (14), and b) that each securing member (16) is adapted to co-operate with said second branch (14). Spreader disc according to any one or any of the claims 1-3, characterized in that each spreader vane (2) is provided with a pressure shoe (20), that is anchored to the spreader vane and comprises a pressure sole (21), the one side (the upper side in Figure 6) of which is adapted to cooperate with the pressure surface (17,18,19) of the pressure arm (16), and the opposite side of which is adapted to cooperate with the surface of the carrier disc (1). Spreader disc according to claim 4, characterized in that the pressure shoe (20) consists of a piece of flat iron bent into U-shape, in the U-branches of which long holes (23) extending at right angles to the pressure sole (21) are provided and adapted to anchor the pressure shoe to the pivot stud (15), there being between the head of the pivot stud (15) and the surface on the spreader vane, from which the pivot stud protrudes, a sufficient distance for the U-branches of the pressure shoe to be supported loosely with one on each side of the pressure arm. Spreader disc according to claim 1, characterized in that each securing mechanism is constituted by a knee-joint mechanism or toggle mechanism adapted for limited movement beyond the position corresponding to "a straight knee".

Inventors: LAURSEN NILS JORN, NIELSEN THORKILD, LAURSEN, NILS JORN, NIELSEN, THORKILD
Applicants: LAURSEN AS A P, A.P. LAURSEN A/S
Application year: 1993
Main classification: A01C17
IPC codes: A01C17