Abstract:
A lawn care vehicle with a tool attachment such as spiral-bladed mowing units arranged in front and underneath the lawn care vehicle in offset fashion. A tool frame to which the tool attachments are mounted is received within rails for allowing the tool frame to shift longitudinally with respect to the rails, thereby allowing the tool frame and tool attachments to shift outwardly with respect to the vehicle frame to maintenance positions.

Description:
BACKGROUND OF THE INVENTION 
     The invention pertains to a lawn care vehicle with a tool attachment that is supported by the vehicle frame. 
     Garden and lawn care vehicles usually contain attachments that are connected to the body of the vehicle by carrying devices. These attachments may consist of lawn care equipment, e.g., mowers with spiral or rotating blades, vertical cutters, raking devices or the like. The attachments are arranged on the body of the vehicle via the carrying devices such that their height can be adjusted, i.e., they can be moved between an operating position, whereby they are in contact with the ground, and a raised position for transport or service. 
     EP-A1 0,217,773 pertains to a riding lawn mower with a chassis that carries a drive unit. This drive unit drives the wheels as well as a cutting device that is separably attached to the chassis. The cutting device can be moved between a lower cutting position and an upper non-cutting position. This adjustment is realized by means of a lever arrangement that makes it possible to adjust the cutting height and completely raise the cutting device. In all these positions, the cutting device remains underneath the vehicle, i.e., the cutting device must be detached for maintenance and service purposes because it is not accessible. 
     U.S. Pat. No. 5,079,907 describes a riding lawn mower that contains a grass cutting device and a blade housing, both of which can be moved between an essentially horizontal mowing position and an upwardly tilted service position. The blade housing is suspended on an adjustment mechanism, one end of which is connected to the blade housing, and the other end of which is connected to the body of the vehicle. In its raised position, the blade housing is tilted toward the rear by the adjustment mechanism in order to gain access to the blades located in the housing. However, such a design can only be realized if the cutting device can be freely moved, i.e., if the cutting device is not entirely or only partially arranged underneath the vehicle. 
     U.S. Pat. No. 5,042,236 discloses a golf lawn mower with a total of five spiral-bladed mowing units. In this case, three spiral-bladed mowing units are arranged in front of the golf lawn mower, and two spiral-bladed mowing units are arranged laterally offset to the three front spiral-bladed mowing units, i.e., underneath the vehicle frame. This arrangement serves for mowing strips of lawn remain between the front spiral-bladed mowing units with the spiral-bladed mowing units offset such that a uniform lawn pattern can be achieved. Here, the front spiral-bladed mowing units are accessible for maintenance and service purposes, but access to the rear spiral-bladed mowing unit is very difficult. 
     EP-B1 0,182,229 pertains to a farm tractor with a so-called front hitch that is arranged on the frame of the farm tractor in horizontally movable fashion. The front hitch serves, for example, for accommodating a mowing mechanism, a soil cultivation device or the like. The horizontal movability makes it possible to alter the existing leverages in such a way that the front wheels can be subjected to a higher load and thus generate a higher tensile force. However, neither the front hitch nor the tool attachment carried by the front hitch is arranged underneath the farm tractor or is otherwise covered. 
     It would therefore be desirable to improve the accessibility of the tool attachments in known garden and lawn care vehicles. 
     SUMMARY OF THE INVENTION 
     The present invention provides a vehicle having a vehicle frame and elongate rail members mounted therewith. A tool frame is provided to which is coupled a tool attachment such as an offset arrangement of spiral bladed reel mower cutting units. The tool frame includes bars which shiftably engage the rails along the length of the elongate rails, and the rails support the bars of the tool frame as the bars and tool frame shift linearly within the rails. The tool frame shifts between a retracted operating position whereat the cutting units are in an operating position in close proximity to the vehicle, and an extended maintenance position whereat the cutting units are shifted outwardly from the vehicle frame for providing access to the cutting units. The bars are received within the respective rails and are shiftable therein in telescoping fashion. When the cutting units are in the operating position one of the cutting units is at least partially within the boundary of the vehicle. 
     The rails are oriented at an angle to a surface of the ground, and the tool frame shifts generally along the rails upwardly and outwardly away from the vehicle as the tool frame shifts to the extended maintenance position. 
     The rails according to the preferred embodiment extend generally longitudinally in the direction of vehicle travel and the tool frame is shiftable along the rails generally longitudinally in the direction of vehicle travel. A linear actuator or hydraulic cylinder engages one of the bars of the tool frame for shifting the tool frame between the extended and retracted positions. 
     A plurality of toothed wheels are provided in engagement with respective toothed rack members fixed with the bars. The wheels are fixed with a shaft supported by the vehicle, and the wheels and shaft rotate in unison to synchronize the shifting of the bars with respect to the rails. 
     A support is mounted with the vehicle frame and engages the tool frame in the retracted position for at least partially supporting the tool frame in the retracted position. 
     Each bar is movably carried within the rail between at least one lower and one upper support roller. 
     The present invention provides tool units located beneath the operating platform or the vehicle frame, and which can be displaced outwardly, i.e., beyond the contours of the lawn care vehicle. Consequently, the tool attachment is easily accessible to the operator. The tool may consist of a mower, e.g., a spiral-bladed or rotating blade lawn mower, a raking device, a clearing blade, a vertical cutter, a soil aerator, a manure spreader or the like. Depending on the position of the tool attachment, it may be practical to move said tool attachment outwardly from the front, the rear or the side of the vehicle in order to gain access. 
     Particular advantage is attained due to the use of an inclined guideway for the tool attachment on the vehicle frame. In this way, the tool attachment can not only be moved out of the area located underneath the lawn care vehicle, e.g., under a protective cover, under the vehicle frame, under an operating platform or the like, but also be raised such that it can be serviced even more easily. 
     The use of at least one bar according to the present invention that is movably accommodated in or on a rail of the vehicle frame represents a robust and simultaneously simple and inexpensive arrangement for carrying the tool attachment. A long guide way, e.g., a telescoping guide way, also helps prevent the occurrence of jams during movement. 
     If several offset tool units are provided, it is possible to arrange a central tool unit between adjacent tool units, i.e., offset toward the lawn care vehicle, so that the central tool unit occupies, for example, the space between two wheels. In this way, the structural length of the lawn care vehicle can be relatively short, i.e., the lawn care vehicle is more compact. 
     Within the spirit of the present invention, the adjustment of the frame may be carried out manually, with a mechanical winch or the like. When using heavy tool attachments, it is advantageous to carry out this adjustment by means of a motor that can preferably be remote-controlled. 
     Resistance against lateral forces can be achieved if the bar of the tool frame is movably arranged in a closed profile, i.e., a tube, wherein one or more longitudinal slots are provided in order to connect the motor if the motor is not arranged concentric with the bar or the rail. Alternatively, the bar may also be realized in the form of a tube, wherein the rail is realized in the form of a carrier, on which the tube is movably arranged. 
     The movement of two or more bars can be realized with the aid of only one motor if the respective bars are connected to one another such that they move synchronously and cannot become jammed. The shifting of the bars can be synchronized by a shaft to which geared wheels or friction wheels are fixed. The wheels can engage respective bars and by way of the shaft help insure that the bars shift together. Synchronous movement of the bars can be achieved since toothed wheels and toothed racks are used to lock the bars together, which results in no slippage. 
     The use of at least one abutment and at least one support on the tool attachment and the lawn care vehicle makes it possible to prevent the weight from affecting the steering when the tool attachment is retracted, i.e., in its normal position. In this way, shocks caused by uneven terrain are barely, if at all, introduced into the bars and rails. 
     A sensor may be provided in order to prevent accidents during the servicing of the tool attachment. This sensor detects when the tool attachment is moved out of its operating position, i.e., that the tool attachment is presumably moved into its maintenance and service position. This sensor may be coupled to motors for driving and/or retracting and/or pivoting the tool attachment by means of simple electrical or electronic switching elements or a computer-assisted control unit, in such a way that the motors are prevented from being activated when the tool attachment is out of its operating position. 
     According to an additional feature, a mechanical locking device that is manually actuated may be provided. This locking device secures the tool attachment to the vehicle frame when it is not in its operating position. This may be simply realized by means of a bolt that is inserted through aligned openings in the tool attachment and the vehicle frame. 
     If the tool attachment contains three spiral-mower tool units that are movably held on the tool frame in overlapping fashion, and if the outer tool units can be vertically pivoted into an idle position, the outer tool units will not only be easier to access because they are able to assume a vertical orientation, but they will also be able to be maintained or serviced in a narrow garage. 
     The bar is guided with little resistance to movement by means of a lower support roller and an upper support roller between the bar and the rail. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a partial schematic representation of a top view of a lawn care vehicle with vehicle frame and tool attachment. 
     FIG. 2 is a partial side view of the lawn care vehicle according to FIG. 1, wherein the tool attachment is in its retracted operating position. 
     FIG. 3 is a partial side view of the lawn care vehicle according to FIG. 1, wherein the tool attachment is in the extended position. 
     FIG. 4 is a detailed perspective representation of portions of the vehicle frame and the tool frame of the tool attachment. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The lawn care vehicle  10  shown in FIG. 1 contains a vehicle frame  12  and a tool attachment  14 , wherein only the front end region of the lawn care vehicle is shown. 
     In the preferred embodiment, the lawn care vehicle  10  is realized in the form of a self-propelled lawn or golf course mower. However, the lawn care vehicle  10  could also be realized in the form of a towed vehicle. This lawn care vehicle  10  is provided with standard equipment (not shown) such as a motor, gearbox, driving platform and the like, i.e., this lawn care vehicle essentially corresponds in many ways to the initially described known vehicles. 
     The vehicle frame  12  serves for carrying the essential components of the lawn care vehicle  10 , of which merely a drivers seat  16  is schematically illustrated. The vehicle frame  12  is supported on wheels  18  in order to move as well as support the lawn care vehicle on the ground. However, only the two front wheels are shown in the figure, i.e., the two steerable rear wheels are not shown. The left and right rails  20 ,  22  of the vehicle frame  12  which extend in the moving direction of the lawn care vehicle  10  are realized in the form of tubes with square or rectangular cross section in the embodiment shown and are of particular importance. However, it should be mentioned that it would also be possible to provide only one rail  20 ,  22  or more than two rails  20 ,  22 . It would also be conceivable to realize the rails  20 ,  22  in the form of solid elements rather than tubes. FIG. 4 shows that the front ends  24  of the rails  20 ,  22  are connected to one another in the form of a “U” via a plate-shaped crosspiece  26  such that a rigid frame is formed. However, the connection by means of the crosspiece  26  is by no means mandatory. 
     The rails  20 ,  22  are positioned in the form of mirror images about the central longitudinal axis of the lawn care vehicle  10  and are arranged on the lawn care vehicle  10  in such a way that the vehicle frame  12  forms an angle with the ground. Consequently, the vehicle frame  12  is closer to the ground in the central region of the vehicle  10  than at the front end of the vehicle  10 . Although the figure shows the protrusion of the vehicle frame  12  beyond the front end of the vehicle  10 , this feature is also not mandatory; the vehicle frame  12  may also protrude laterally or toward the rear. 
     The right rail  22 , viewed in the driving direction, is provided with a longitudinal slot  28  between its open ends. This longitudinal slot extends in the side  30  which faces the other rail  20 , at least over the adjustment range of the tool attachment  14 . 
     An opening  32 , the purpose of which will be described below, is arranged on the underside of each rail  20 ,  22 . 
     On the front side of the crosspiece  26 , i.e., on the side that faces the tool attachment  14 , a support  34  is arranged within the protruding region of each rail  20 ,  22 , on each side. This support is realized in dimensionally stable fashion and provides a support surface  36 , wherein said support also contains an opening  37  that is realized in the form of a slot. 
     A bolt  38  that extends through the central longitudinal axis of the longitudinal slot  28  is arranged on the side  30  behind the crosspiece  26 . 
     Each rail  20 ,  22  is provided with front and rear recesses  40 ,  42  in the region of the crosspiece  26  and in the central region of the rail. The first recess is located at the bottom  44  of each rail  20 ,  22 , the second at the top  46  of said rail. A plate  48  that contains a bore  50  is preferably welded or screwed to the side  30  within the region of each recess  40 ,  42 . 
     A support roller  52  that is rotatably accommodated on a bolt member is assigned to each plate  48  and each recess  40 ,  42 . Each bolt member is inserted into a corresponding  15  bore  50  and secured with a nut  56 . The support rollers and their respective positions relative to the rails  20 ,  22 , are realized such that their circumferential surfaces slightly extend over the inner surface of the rail  20 ,  22 . 
     A bearing bracket  58  is screwed or welded to each respective connecting rail (not shown) which connects the rails  20  and  22  to one another, within the region of the opening  32  in the bottom  44  of each rail  20 ,  22 . These bearing brackets accommodate a rotatable shaft  60 . Of course, the bearing brackets  58  may also be directly arranged on the rails  20 ,  22 . The respective ends of the shaft  60  are equipped with wheels  62  that are connected to the shaft without rotational play. In the preferred embodiment shown, these wheels are realized in the form of toothed wheels. The two wheels  62  are thus also connected without rotational play. The distance between the wheels  62  on the shaft  60  and their arrangement on the shaft  60  relative to the rails  20 ,  22  are chosen such that the given wheel  62  protrudes into the interior of the respective rail  20 ,  22  through the openings  32 . The shaft  60  is transverse to the longitudinal direction of the rails  20 ,  22 . The mounting of the wheels  62  on the shaft  60  and the mounting of the bearing brackets  58  on the rails  20 ,  22  or at another location of the lawn care vehicle  10  or the vehicle frame  12  is realized by means of known fasteners that are not shown in detail, e.g., wedges and screws. 
     In addition, holders, brackets and sheet metal that are not shown in detail are arranged on the rails  20 ,  22 . These elements represent parts of the lawn care vehicle  10  which are not essential to the invention. 
     In the preferred embodiment shown, the tool attachment  14  is composed of several tool units  64  and a tool frame  66 . 
     The tool units  64  in the embodiment shown are realized in the form of known, hydraulically driven spiral-bladed mowers. Three tool units  64  are arranged adjacent to one another transverse to the driving direction, wherein the two outer tool units  64  are offset ahead of the central tool unit  64 , i.e., away from the lawn care vehicle  10 . In this way, it is possible for the central tool unit  64  to occupy the region between the wheels  18  during the operation of the lawn care vehicle, i.e., the tool attachment  14  will not protrude too far ahead of the lawn care vehicle  10 . As seen from the driving direction, the two outer tool units and the central tool unit  64  overlap, i.e., no unmoved strips of grass will remain during mowing. All tool units  64  are at the same distance from the ground; their height can be adjusted by means of a lifting device  68  in order to adjust the tool units to a different cutting height or move the tool units into the transport position. For reasons of simplicity, only one lifting device  68  is shown for the embodiment shown. However, a separate lifting device may be provided for each tool unit, which embodiment is also covered by the term lifting device. 
     The two outer tool units  64  are suspended in vertically pivoted fashion in schematically represented bearings  70 . 
     The design of the tool units  64  in the form of spiral-bladed mowers only represents an example of various types of tool units  64 . It would also be possible to use raking devices, rotating blade mowers, vertical cutters, pick-up implements, clearing blades and the like. 
     In the embodiment shown, the tool frame  66  is composed of at least left and right bars  72 ,  74  and a carrier  76 . A front carrying arm  78  and a rear carrying arm  80  are connected to this carrier  76  in the form of a separate attachment bracket that serves as the carrier for all tool units  64 . 
     The tool frame  66  is essentially in the form of a U, wherein the base of the “U” extends transverse to the driving direction and the arms of the “U” extent in the driving direction. In addition, the tool frame can be moved relative to the vehicle frame  12  in the driving direction. 
     The left and right bars  72 ,  74  form mirror images about the longitudinal axis of the lawn care vehicle  10  and are provided with mounting plates  82  at their front ends in order to connect the carrier  76 . Each mounting plate  82  is equipped with an abutment  84  on its rear side, i.e., on the side that faces the rails  20 ,  22 . These abutments are arranged in such a way that they can be placed onto the respective supports  34  when the tool frame  66  is retracted. On the side of the abutment  84  which faces the vehicle frame  12 , a pin  85  is provided which is designed and arranged on the abutment  84  in such a way that it is held in the respective opening  37  with almost no play and remaining secure in its position when the tool attachment  14  is retracted. The support  34  may be provided with a hard rubber block in which the opening  37  is arranged. The positive connection between the pin  85  and the opening  37  absorbs torsional movements of the tool attachment  14  relative to the vehicle frame  12  and consequently reduces relative movements and vibrations between said components. 
     The cross section and the orientation of the bars bar  72 ,  74  can be accommodated in a rail  20 ,  22  that faces the respective bar in sliding fashion. 
     A cutout  86  is provided on the underside of each bar  72 ,  74 . This cutout serves to accommodate a toothed rack  88  that is aligned with the longitudinal direction of the bars  72 ,  74 . The length of the toothed rack  88  depends on the range of adjustment of the tool frame  66 . 
     Within the rear region of the right bar  74 , a bore  90  is arranged which serves for accommodating a screw  100  for mounting a linear actuator or motor  94  on the bar  74 . A holder  92  that is also arranged within this region may be utilized for mounting a valve or the like for controlling the motor  94 . 
     The carrier  76  is realized in the form of a plate that is screwed to the two mounting plates  82  and is provided with a series of openings for connecting the carrying arms  78 ,  80 . However, the bars  72 ,  74  may also be welded to the carrier  76 . 
     The front carrying arm  78  extends forward from the carrier  76  in order to accommodate the two front, outer tool units  64  in the bearings  70 . 
     The rear carrying arm  80  extends backward from the carrier  76  into the free space between the two wheels  18  in order to carry the central tool unit  64 . 
     Both carrying arms  78 ,  80  may be engaged on the carrier  76  in rigid or vertically movable fashion or accommodate the tool units  64  such that they can be vertically moved in order to compensate for uneven areas in the ground. 
     A sensor (not shown) is arranged on the rails  22  and generates a signal as a function of whether the bars  72 ,  74  are pushed into the rails  20 ,  22  or not. However, it would suffice merely to detect a movement of one bar  72  or  74  relative to the given rail  20  or  22  respectively. The sensor may also be arranged at a different location, e.g., on the carrier  76 . 
     The motor  94  is realized in the form of a hydraulic cylinder and piston assembly, wherein said motor can be actuated by means of a hydraulic control circuit (not shown). The hydraulic cylinder can be loaded on both sides of the piston, i.e., it can be actively adjusted in both directions. One end of the motor  94  is held via the bolt  38 , and the other end is held on the bar  74  via the bolt  100 . The mounting of the motor  94  via the bolts  38 ,  100  takes place as close as possible to the side  30  in order to keep bending moments to a minimum. However, it is also conceivable to use a pneumatic or electric motor, or equivalent structure, instead of the hydraulic motor  94 . In addition, a mechanical rod assembly, mechanical levers or a tackle may be utilized instead of the motor  94 . 
     The sensor is physically or logically coupled to the drive (not shown) of the tool units  64 , the lifting device  68  and a pivoting motor (not shown) for the outer tool units  64 , in such a way that said components cannot be actuated if the sensor indicates that the tool frame  66  is no longer in the retracted position. An additional connection of the sensor to the motor  94  and a safety interlock system (not shown) may also be provided. 
     The drive of the tool units  64  can alone be deactivated, or all of the drives can be deactivated. 
     According to the previous description, the lawn care vehicle has the following design and function. 
     The rails  20 ,  22  and the plate  48  represent part of the vehicle frame  12 , i.e., fixed components of the lawn care vehicle  10 , and are already installed in the correct position. 
     The tool frame  66  is assembled in the form of a U; the assembly includes the toothed racks  88 , but not the bolt  100  and the holder  92 . Subsequently, the bars  72  and  74  of the tool frame  66  are pushed into the hollow spaces of the rails  20 ,  22  such that the underside of each bar abuts the front support roller  52  and the upper side of each bar abuts the rear support roller  52 . Consequently, a rolling support is achieved instead of a sliding support. Contact with the underside and the upper side is automatically attained due to the leverages during the insertion of the bars  72 ,  74 . As soon as the bars  72 ,  74  are pushed into the rails  20 ,  22  up to the adjustment range, the wheels  62  begin to mesh with the toothed racks  88  and, from this moment, ensure a synchronous movement of both bars  72 ,  74  during the additional insertion. Consequently, tilting or jamming of the bars is hindered. As soon as the bars  72 ,  74  are entirely pushed into the rails  20 ,  22 , the bolt  100  is inserted into the longitudinal slot  28  and screwed onto the inner side of the right bar  74 . The motor  94  which is extended to its maximum length is then secured via the two bolts  38 ,  100  and connected to the hydraulic system (not shown). 
     In this inserted state, the sensor is activated and the abutments  84  rest on the supports  34  in order to relieve the bars  72 ,  74  that rest on the support rollers  52  in the rails  20 ,  22 . 
     The carrying arms  78 ,  80  are installed individually or in the form of an attachment bracket that contains both carrying arms, whereafter the tool units  64  are attached to the carrier  76  and connected to the corresponding drive. 
     FIGS. 1 and 2 show the lawn care vehicle  10  with a tool attachment  14 , the tool frame  66  of which is entirely pushed into the vehicle frame  12  and its respective rails  20 ,  22 . In this position, the tool units  64  almost touch the ground and can be lowered onto the ground by means of at least one lifting device  68 . The central tool unit  64  is located between the wheels  18 , i.e., within a contour  98  of the lawn care vehicle  10  that, for example, is formed by the plate  26 , the front edge of the wheels  18  or a structure of the lawn care vehicle  10  and may have a quite irregular shape. 
     In order to extend the tool frame  66 , the hydraulic cylinder  94  extends such that it moves the bars  72 ,  74  inside the rails  20 ,  22 , i.e., such that the tool attachment  14  is moved from a position in which it is near the lawn care vehicle  10  into a position in which it is farther away from the lawn care vehicle. This means that the tool attachment  14  with its tool units  64  is moved out of the boundary  98  of the lawn care vehicle  10  so that it may be serviced. The connection between the left toothed rack  88  and the left wheel  62  and the right toothed rack  88  and the right wheel  62  via the shaft  60  helps ensure a synchronous movement of both bars  72 ,  74 . 
     It is quite obvious that a second motor  94 , a second longitudinal slot  28  and a second set of bolts  38 ,  100  may be used instead of the toothed rack  88 , the wheels  62  and the shaft  60 , whereby the motors  94  could operate synchronously, e.g., by means of a synchronizer. 
     In FIG. 3, the tool frame  66  is shown in its extended position, in which the central tool unit  64  is moved out of the region between the wheels  18 , and into a position in which it is easily accessible for maintenance and service. Although the inclined arrangement of the rails  20 ,  22  is not absolutely mandatory, it is advantageous in that the tool units  64  can also be lifted off the ground in the extended position such that access to the tool units  64  is enhanced and maintenance simplified. 
     Since the sensor is no longer activated in this position, the drive cannot be actuated in the extended position in order to protect maintenance and service personnel.