Abstract:
A device for a riding mower having a wheel born chassis ( 11,12 ) intended to support the operator, an engine ( 14 ) for driving at least one wheel ( 13 ) and cutting knives ( 31 ) arranged in a front mounted cutting unit ( 17 ). The cutting unit is placed such that at least a part of the cutting unit is situated close beneath the front part of the chassis. The mower is provided with a first pivot ( 26 ) arranged in front of the chassis and about which the cutting unit ( 17 ) is turnably arranged. The cutting unit is adapted to move forward whereby a support ( 55 ) arranged on the cutting unit engages the ground and the rear part of the cutting unit is then moved forwardly at the same time as the front part of the cutting unit is turned upwards about the first pivot ( 26 ) to a maintenance position.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a device for a riding mower having a wheel-born chassis supporting the operator, an engine for driving at least one of the wheels and at least one cutting means arranged in a front mounted cutting unit that is placed such that at least a part of the cutting unit is situated close beneath the front part of the chassis. 
     2. Description of the Related Art 
     Riding mowers of the type mentioned above are previously known, see for instance EP 213096. Such mowers comprise a front part and a rear part. The front part supports the operator, the cutting unit, which is placed in front of the two front wheels, and the engine. The rear part supports the two rear wheels. The two parts are pivotally arranged with respect to one another about a vertical axis and a horizontal axis oriented in the direction of movement. This design gives a neat and easily driven mower having a minimal turning radius. Also, the mower s cutting unit is positioned such that the operator has a good view of the area being cut. 
     In order to achieve a vehicle that is as compact as possible and to minimize the total length of the mower, the cutting unit is placed close to the two front wheels. However the necessary space for the legs of the operator and the foot control means demands that the chassis extends forward such that it is partly placed above the cutting unit. This means that the lower side of the cutting unit, without being heavily demounted, is difficult to reach for cleaning and maintenance. 
     It has, for other types of riding mowers with front mounted cutting units on the market, namely such mowers on which the cutting unit is placed completely in front of the chassis, see U.S. Pat. No. 5,079,907, been suggested to facilitate cleaning and maintenance by making the cutting unit foldable to a mainly vertical position. For this type of mower, a link arm mechanism is used that is fastened to the cutting unit at each side of the mower at the area of the front wheel axis. This means that the turning motion of the cutting unit, depending on the forwardly extending position of the cutting unit, can be made without the cutting unit being hindered by the chassis. 
     SUMMARY OF THE INVENTION 
     The present invention is directed toward an arrangement that removes the disadvantages mentioned above and makes it possible to move the cutting unit easily to such a position facilitating service and maintenance while maintaining a desirably compact structure. 
     In accordance with the present invention, cutting means are arranged at a front mounted cutting unit, and the cutting unit is placed such that at least a part of the cutting unit is situated beneath the front part of the chassis. Means are also provided for moving the cutting unit forward with respect to the chassis such that support means arranged on the rear part of the cutting unit engage the ground. The rear part of the cutting unit can then be moved forwards at the same time that the front part of the cutting unit is turned upwards about a first pivot to a maintenance position. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and further features of the invention will be apparent with reference to the following description and drawings, wherein: 
     FIG. 1 is a side view illustrating a riding mower incorporating the present invention; 
     FIG. 2 is a plan view of a part of the cutting unit for the mower with its support system; 
     FIG. 3 is a vertical section as seen along line III—III in FIG. 2; 
     FIG. 4 is the same section as FIG. 3, but with the cutting unit in a first position before it is folded up; 
     FIG. 5 shows the same section as FIGS. 3 and 4, but with the cutting unit in a partly folded up position; and, 
     FIG. 6 shows the same section as in FIGS. 3-5, but with the cutting unit in a completely folded up position. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     As shown in FIG. 1, a riding mower  10  includes a front chassis part  11  which, by means of a pivot (not shown), is turnably secured about a horizontal axis as well as a vertical axis to a rear chassis part  12 . The rear chassis part is supported by two rear wheels  13 . The mower is also provided with a drive unit  14 , such as an internal combustion engine. 
     The front chassis part  11  is supported by two front wheels  15 , and has a seat  16  for the operator and a cutting unit  17  which is partly covered by one or more protecting hoods  18 . The cutting unit  17  is, at its front end, supported by two supporting rollers  19 . The front chassis part  11  is also provided with necessary control means, such as a steering wheel  20 , control means (not shown) for lowering and raising the cutting unit  17 , and for adjustment of the cutting height, etc. 
     The cutting unit  17  is supported by a supporting frame  21  (FIGS.  2 - 6 ), which is turnably secured for vertical movement about a pivot point  22  arranged at the front chassis part  11 . The supporting frame  21  is under the influence of two springs  23 . The springs  23  are fastened to the front chassis part  11  and help lift the cutting unit  17 . The supporting frame  21  can be raised and lowered by means of a lifting mechanism (not shown) in order to move the cutting unit between a raised transport position and a lowered cutting position. 
     A front part of the supporting frame  21  is provided with two side plates  24  that are fastened to a link arm  25  by means of a first pivot or hinge  26 . The first hinge  26  permits a turning motion of the link arm  25  with respect to the supporting frame  21  about a horizontal axis arranged perpendicular to the driving direction. The link arm  25 , which is directed obliquely downwards in front of the front chassis part  11 , is provided with a through hole  27  arranged below and in front of the first hinge  26 . The hole  27  is arranged to be positioned in line with openings  28  in the side plates  24  in order to lock the link arm  25  with respect to the supporting frame  21  by means of a locking pin  29 . 
     The cutting unit  17  comprises an up-side-down trough-shaped hull  30  that, in a conventional manner, encloses several horizontal knives  31  arranged on several vertical shafts driven from the driving unit  14  by means of a drive belt  32  connected to a central drive belt  33  whose shaft by means of another drive belt (not shown) drives the other knives. The front part of the cutting unit  17  is, at its upper side, provided with a central upstanding lug  34  forming a second pivot  35  to which a lower end of the link arm  25  is turnably arranged. 
     The cutting unit  17  is, at its upper side, provided with a front transverse rod  36  and a rear transverse rod  37  that are turnably secured to the cutting unit at a front pivot point  38  and a rear pivot point  39 , respectively. The rods  36 ,  37  are provided with bent end parts  40 ,  41  that are turnably arranged to front and rear brackets  42 ,  43  arranged on a support beam  44  extending about the cutting unit and supporting the support rollers  19 . The two rods  36 ,  37  are connected to one another by a link arm system including first, second, and third link arms  45 ,  46 ,  47 . The first link arm  45  is secured to the rod  36 , the second link arm  46  is secured to the rod  37 , and the third link arm  47  connects the first and second link arms  45 ,  46  to one another. Thus, the two transverse rods  36 ,  37  achieve a synchronous turning motion, which means that the cutting unit  17  is moved vertically parallel to the surface beneath. The first link arm  45  also supports a front rod  48  that has one end pivotally secured to the link arm  45 . An opposite end of the front rod  48  is provided with a hook  49  that is removably connected to a loop  50  on a rear rod  51  that can be acted on to adjust the cutting unit  17  to a desired cutting height. 
     The support frame  21  is provided with a yoke  52  extending between two legs of the frame  21 . A lower side of the yoke  52  is provided with a support  53  on which a tongue  54  normally rests. The tongue  54  extends from, and is fixed to, the rear transverse rod  37  and pivots together with the rod  37 . Thus, the rear part of the cutting unit  17  is manually supported by the support  53 . The support beam  44 , which is placed on the cutting unit, also supports two support wheels  55  which might be removably arranged and which are placed at the rear part of the cutting unit and at each side thereof. The purpose of the supporting wheels will be described below. 
     The device operates in the following manner. Cutting takes place by lowering the cutting unit  17  toward the surface by means of the support beam  21  and manually controlled means (not shown) belonging to the beam which means that the supporting rollers  19  engage the surface. Since the tongue  54  rests on the support means  53 , which is connected to the yoke  52  of the support beam  21 , the rear part of the cutting unit  17  will be lifted up from the ground during the cutting operation. A suitable cutting height can be set by moving the rear rod  51  in its length direction by means of manually operated control means (not shown). Thus, moving the rod  51  means that the cutting unit is raised or lowered with respect to the supporting frame  21 , this movement taking place with the cutting unit parallel to the ground. During cutting, the cutting unit can, because of the central support at the tongue  54  and the support means  53  and at the comparatively loose, centrally placed, bearing  35 , turn somewhat about an axis which is parallel with the driving direction in order to take up slight variations in inclination of the ground. The ground inclination is also, in a conventional manner, taken up as a turning motion between the front and the rear chassis parts  11 ,  12 . 
     In order to undertake maintenance or cleaning of the cutting unit, the cutting unit  17  is placed in its operating position and is adjusted for the lowermost cutting height according to FIG.  3 . Then the front rod  48  is removed from the rear rod  51  by removing the hook  49  from the loop  50  after which the drive belt  32  is released by moving a tensioning pulley cooperating with the drive belt to an inactive position. Then the locking pin  29  is withdrawn from the hole  27  and the opening  28  such that the two side plates  24  of the support beam  21  are released from the link arm  25 . This means that the side plates  24  and the link arm  25  can be turned with respect to one another about the first pivot  26 . Then the front part of the support frame  21  is pressed manually downwards towards the ground, thereby moving the rear part of the cutting unit toward the ground until the support wheels  55  engage the surface (FIG.  4 ). Continued depression of the support frame  21  moves the complete cutting unit forward under the influence of the link arm  25 , which is turned about the first and second pivot  26 ,  35 . This causes the tongue  54  to disengage from the support means  53 . 
     Thereafter, the pin  29  is inserted into the openings  28  of the side plates  24  and the support frame  21  is released, which means that the support frame returns by spring action to the position shown in FIG. 4 by means of the springs  23  such that the link arm  25  will rest on the pin  29 . It is now possible to manually move the rear part of the cutting unit  17  in the forward direction with the support wheels  55  in engagement with the ground. This forces the cutting unit to turn about the second pivot  35  to the position shown in FIG. 6 such that the underside of the cutting unit becomes accessible for cleaning and maintenance. In a corresponding way the mower is returned to its original position by making the above steps in reverse order. 
     While the preferred embodiment of the present invention is shown and described herein, it is to be understood that the same is not so limited but shall cover and include any and all modifications thereof which fall within the purview of the invention.