Abstract:
A quick-change mowing blade arrangement is provided. The mowing blade has a shaped feature and a hole which maintain a certain spacing X from one another. For installation, the mowing blade is held, by means of the hole, pivotally on a head of a peg. If the head) undergoes an impermissible amount of wear, the shaped feature is no longer hidden by a cover of the mowing cutter disc, but becomes visible.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates to a mowing cutter disc having a mowing blade and a holder. The holder being supported by the mowing cutter disc and being suitable for passing through a hole in the mowing blade. In the installed condition an inner region of the mowing blade is hidden while an outer region is exposed. The holder may not exceed a maximum permissible amount of wear. The invention further relates to a mowing blade. 
       BACKGROUND OF THE INVENTION 
       [0002]    German patent document DE 195 21 067 A1 discloses the possibility of securing mowing blades to a mowing cutter disc by way of a quick-change mechanism. In a quick-change mechanism of this kind, a holder in the form of a bolt or peg is pivoted into a change-over position such that it comes out of engagement with the mowing blade so that a new mowing blade can be inserted. 
         [0003]    The problem on which the invention is based exists in the fact that when the mowing blade is replaced it is not possible—or only with great difficulty—to notice wear on the holder. 
       SUMMARY OF THE INVENTION 
       [0004]    According to the invention when a new mowing blade is inserted, the shaped feature on the inner region becomes visible if the holder has undergone an impermissible amount of wear. This result serves as an indication that the holder should also be replaced. The shaped feature may be anything which is noticeable even during the harsh and dirty operating conditions of agricultural machinery. In particular the shape feature may be a notch, a groove, an opening, a shoulder, impressions, welded-on parts, etched areas, high-resistance raised elements which are glued on, welded on, soldered on, shrunk on, etc. These features may have one or more stages and so correspond to different degrees of wear. It is also conceivable to provide the visual feature not on the mowing blade itself but on an element mounted on the holder, parallel to the mowing blade, such as a metal strip, or for an end edge of this element to take on the shaped feature. This element would also become visible if the holder were worn, by means of a hole surrounding the holder, and could provide an indication of wear. The invention could also be used in similar manner if the hole were not in the mowing blade but in the mowing cutter disc and the holder were not secured in the cover or a securing element but on the mowing blade. 
         [0005]    The mowing cutter disc includes a cover and a securing element which may rotate together, but may be separated from one another and are movable relative to one another. The holder for fixing the mowing blade may be secured to either of these two parts, in which case it is important that they may be moved away from one another so that a mowing blade can be inserted or removed. 
         [0006]    If the inner region could also be covered by a different cover (mower housing, blade holder, deflector, etc.), it is useful if it is covered by a cover of the mowing cutter disc, because this always rotates with it and the cover does not need to be put into a particular position in which the position of the shaped feature has to be determined for the wear to be noticed. 
         [0007]    If the shaped feature is selected such that it forms a shoulder or the like which may come into abutment against the outer periphery of the mowing cutter disc when the wear limit is reached, the mowing blade becomes immobile and is thus prevented from performing a back-and-forth movement against the mowing cutter disc which would cause further wear. In addition, stopping in this manner is noticed immediately. 
         [0008]    Mowing blades may be constructed in various forms (rectangular, triangular, double-bladed, etc.) and may be used in various mowing machines, having horizontal or vertical mower bars. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    An exemplary embodiment of the invention is described in more detail below with reference to the accompanying drawings, wherein: 
           [0010]      FIG. 1  is a schematic illustration of a mowing machine in side view, in which a mowing cutter disc having a mowing blade is visible; 
           [0011]      FIG. 2  is a sectional illustration of a mowing blade, fixed to a mowing cutter disc, in a non-worn condition; 
           [0012]      FIG. 3  is the illustration from  FIG. 2 , in a worn condition; 
           [0013]      FIG. 4  is a mowing blade with a shaped feature, in plan view; and, 
           [0014]      FIG. 5  is a perspective view of the mowing cutter disc, with the mowing blade and the shaped feature. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0015]      FIG. 1  shows a mowing machine  10  having a housing  12 , an undercarriage  14 , a draw bar  16 , a mower bar  18  having mowing cutter discs  20  and mowing blades  22 , a device  24  for processing cuttings and a cutting feed device  26 . 
         [0016]    The mowing machine  10  is in this case illustrated as a drawn or towed arrangement; this is irrelevant, since the important features are only the mowing cutter discs  20  and the mowing blades  22  secured thereto; instead of this, the mowing machine  10  may also be mounted on a coupling device or be of self-propelled construction. A mowing machine  10  of this kind is used primarily in agriculture to mow grass close to ground level. 
         [0017]    The housing  12  upwardly and laterally covers the mower  18  such that no one can erroneously come close to the mower  18  and no cuttings can be flung off. 
         [0018]    The undercarriage  14  includes two laterally mutually spaced wheels and a chassis to which the wheels and indeed the housing  12  are vertically movably connected. 
         [0019]    The draw bar  16  extends forwards from the undercarriage  14  and serves to connect the mowing machine  10  to a towing vehicle such as an agricultural tractor. 
         [0020]    The mower  18  extends transversely to the direction of travel of the mowing machine  10  and over the entire width thereof. The underside of the mower  18  is formed by a mower bar  28  in the form of a gearbox in which the mowing cutter discs  20  are borne drivably such that they are rotatable about substantially vertical axes. 
         [0021]    The mowing cutter discs  20  are constructed such that they are substantially oval, triangular or round in plan view and are provided in the narrow end regions, corner regions or around the circle of the periphery with a respective holder  30 , these being evenly distributed and each for receiving a mowing blade  22 . The mowing cutter discs  20  rotate at a slight spacing above the mower bar  28 . The mowing cutter discs  20  include a cover  52  and a securing element  32 . The securing element  32  is provided below the cover  52  and is connected to it such that it cannot rotate in relation thereto. In this exemplary embodiment, the securing element  32  is constructed as a leaf spring and extends under the holder  30 . In the operating condition, the mowing cutter discs  20  are driven at approximately 2000 rpm and are exposed among other things to soil, stones, foreign bodies and so on which reach the region of the holder  30  and subject it to wear. 
         [0022]    In this exemplary embodiment, the mowing blades  22  are constructed as rectangular, as seen in plan view (see  FIG. 4 ) and made of forged steel; they may be shaped to be planar, twisted, cropped, bent or shaped in any other way to obtain excellent wear and cutting/feeding properties. The mowing blades  22  are provided in a radially inner region  48  with a largely round hole  34  and in an opposing, outer region  50  with a shaped feature  36  on the upper side. The side of the shaped feature  36  that faces the holder  30  is at a spacing “X” from the inner edge of the hole  34 , the edge remote therefrom. 
         [0023]    The device  24  for processing cuttings is in this case constructed as a toothed rotor which takes up the cuttings from the mower  18  and conveys them overhead to the rear, that is to the right as seen in  FIG. 1 . It is not necessary for a device  24  of this kind for processing cuttings to be provided or to be constructed as a toothed rotor. 
         [0024]    The cutting feed device  26  is constructed as a curved sheet-metal hood which guides the cuttings over part of a circle arc. 
         [0025]    The holder  30  includes a peg  38 , screw, bolt, projection or the like whereof, in the installed condition, the upper end region  40  is secured in the cover  52  by means of a nut  42  and whereof the lower end region is provided with a head  44  which is constructed to be wider than the rest of the peg  38 . The head  44  projects downwards into a recess  46  in the securing element  32  and is considerably longer than the mowing blade  22  is thick. The head  44  is dimensioned such that it fits into the hole  34  in the mowing blade  22  with little play. The holder  30  could also be secured in the securing element  32 , in which case it would extend into a recess  46  in the cover  52 . 
         [0026]    The securing element  32  is provided with the recess  46 , in which the head  44  is received with as little play as possible. The securing element  32  is urged towards the holder  30  by an internal or external spring force, such that on the one hand it securely receives the head  44  and on the other it secures the mowing blade  22  between itself and the holder  30  or the underside of the cover  20 . The securing element  32  may be pressed away from the cover  52 , in opposition to the spring force, by means of a lever (not shown), such that the head  44  is released and a gap is produced between the end face of the head  44  and the securing element  32  or the cover  52 , and a mowing blade  22  may be installed or removed through this gap. 
         [0027]    In the installed condition of the mowing blade  22 , the hole  34 , the head  44  and the recess  46  are concentric in relation to an axis which at the same time forms the pivot axis of the mowing blade  22 . 
         [0028]    In this case, the shaped feature  36  is constructed as a permanently visible notch made in the upper side of the mowing blade  22 ; as described at the outset, the shaped feature  36  may also be of a completely different construction and may also be provided on the underside or laterally if this is more advantageous. 
         [0029]    From the description above it follows that the layout and function are as follows: 
         [0030]    To install a mowing blade  22 , the securing element  32  is pressed downwards, away from the cover  52 , and a mowing blade  22  is inserted through the gap that is thereby produced, between the underside of the head  44  and the upper side of the securing element  32 , such that the hole  34  therein comes into congruence with the head  44 . Then the securing element  32  is released, and under the action of the spring it moves towards the cover  52 , wherein the head  44  is received in the recess  46 ; this secures the mowing blade  22  to or around the holder  30 . After installation, the mowing blade  22  is drawn radially away from the axis of rotation of the mowing cutter disc  20 . If the shaped feature  36  becomes visible in the end position of the mowing blade  22  (see  FIG. 3 ) then wear has arisen thereon at the side of the peg  38  which is on the left as seen in  FIG. 3 , and this makes it imperative to replace the holder  30  as well. 
         [0031]    Having described the preferred embodiment, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims.