Abstract:
A plurality of modular-construction hand-operated motorized devices, including a lawn mower, a verticutting implement, a sweeping device, and a device for loosening the soil or taking in and blowing out leaves are disclosed. Each device includes a limited number of differently designed and dimensioned main and additional modules which provide for a wide range of individually adapted types of devices to be constructed.

Description:
BACKGROUND OF THE INVENTION 
     The hand-operated motorized lawn mowers currently available for gardening have a self-supporting chassis which, as the central element, absorbs all the operating forces and on which all the add-on parts are fastened. The manufacturer supplies these lawn mowers in a small number of predetermined variations, which differ essentially only in respect of their cutting width and their drive. The individual mass-produced types of mower are adapted more or less to the requirements and the wishes of the consumers and are equipped either with an internal combustion engine or with an electric motor with mains connection or storage-battery operation, it obviously being necessary for the power of the motors to be adapted to the cutting width. Once the customer has bought a lawn mower of a certain type, it is no longer possible to make any changes, in particular in respect of power and cutting width. If the customer was mistaken in respect of the set-up which is optimal for his/her requirements, or there was a change in requirements on account of a newly acquired surface area requiring cutting, this change could only be taken into account by a new type of mower, accordingly better adapted to the requirements, being bought. Even with damage to a part, for example the chassis, or with failure of a functional element, repair of the conventional mass-produced lawn mowers was not economically viable, with the result that, in this case too, it was necessary to make a new purchase. 
     On the other hand, the types of lawn mower brought out in a small number of predetermined series allowed rational semi-automatic production, which had a favorable effect on the price for the consumer. 
     In contrast to the abovemetioned lawn movers, in which there is provided a rigid chassis which accommodates the running wheels and bears the add-on parts fastened rigidly on it, U.S. Pat. No. 3,537,720 has disclosed a lawn mower in which two wheel-support frames are mounted such that they can be moved to a limited extent with one another and with the add-on parts. In this case, two lateral frame parts which accommodate the running wheels are connected to a transversely running rear wall via articulation elements, and the cutting-unit hood, which bears the motor, is connected to the lateral frame parts via two further articulation elements. This is intended to achieve the situation where, in the case of uneven terrain, all the wheels remain in contact with the ground. As a result, it is intended for the gap between the mower and the ground to be kept small in order to prevent stones or the like which are slug out by the cutting blades from escaping in the outward direction and causing injuries. This risk of hard objects being slug out is intended to be prevented by a trailing roller rolling on the ground, as a result of which the gap, which is open to the rear, is covered in its entirety. In this specific construction, this known mower is obviously mass-produced. Modifications are not provided. 
     A lawn mower designed in modular fashion in accordance with the generic type is known from EP-A-0 193 186. This lawn mower has, as its main module, a core part onto which it is possible to add, in the direction of travel of the lawn mower, front and rear additional housing parts which bear the running wheels. This is intended to make it possible for one and the same additional part containing, for example, the wheels and the handle to be combined with different core parts, for example with larger and/or wider core parts. 
     U.S. Pat. No. 2,265,545 discloses a lawn mower with a rigid frame with a motor bearing and axle bearings and an articulated guide bar and with a running gear, a motor unit and a cutting unit. For the purpose of space-saving dispatch from the factory to the customer or store owner, these various parts are intended to be packaged separately from one another and to be assembled only at the intended destination. Different possible combinations are not provided here. 
     A lawn mower which may optionally be equipped with different additional parts, e.g. with rigid or articulated handles or either adjustable or fixed wheels, is known from U.S. Pat. No. 4,422,283. 
     BRIEF SUMMARY OF THE INVENTION 
     the object of the invention is to provide a modular-construction hand-operated motorized lawn mower which, in conjunction with a limited number of differently designed and/or dimensioned main and additional modules, makes it possible for a wide range of individually adapted types of lawn mower to be constructed and made available at a reasonable price. 
     The set object is achieved by the features specified in the defining part of patent claim 1. 
     It is possible in the same way to construct, in modular fashion, a hand-operated motorized verticutting implement according to patent claim 2, a hand-operated motorized sweeping device according to patent claim 3 or a hand-operated motorized device for loosening the soil or for taking in and blowing out leaves according to patent claim 4. 
     Since the rigid frame may be designed in a comparatively straightforward manner such that, without any damage being caused, it absorbs all the loading occurring in unusual operating states, optimum adaptation to lawn mowers of different sizes and/or powers. 
     Despite the variety of different types of lawn mower which are to be produced in a customer-specific manner, cost-effective production can take place in a manner known per se in that, with computer aid, on a production line, the respectively necessary modules are fed and fitted, if appropriate, automatically. 
     Further configurations of the invention can be gathered from the subclaims. A suitable running gear, in general, is a double-axle running gear with four wheels which are arranged in a manner known per se such that they can be height-adjusted together, via an adjusting lever, in order for it to be possible for the operating height to be adjusted. Instead of the rear wheels, it is also possible for a running roller to be arranged in a module of corresponding design. The invention also makes it possible, instead of the cutting unit for lawn-mowing purposes, to arrange other tool subassemblies, for example verticutting blades or a device for loosening the soil or else a device for sweeping together or for taking in and blowing out, for example, leaves. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Exemplary embodiments of the invention are described a hereinbelow with reference to the drawing, in which: 
     FIG. 1 shows a perspective view of a lawn mower designed in modular fashion according to the invention; 
     FIG. 2 shows the lawn mower according to FIG. 1 in a partly assembled state; 
     FIG. 3 shows a perspective illustration of individual modules from which the lawn mower according to FIG. 1 is assembled; 
     FIG. 4 shows a perspective view of a modular-construction rigid frame; 
     FIG. 5 shows a perspective view of the frame according to FIG. 4 with motor supports inserted; 
     FIG. 6 shows a perspective illustration of a modular system with four running wheels, axles and a connecting rod for operating height adjustment; and 
     FIG. 7 shows a schematic illustration of modules which can be assembled in different ways. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In order to explain the basic construction, you are referred first of all to FIGS. 3 to  7 . The load-bearing element provided is a double delta frame  10  which comprises two longitudinal supports  10 . 1  which slope up obliquely from front to rear, two rear supports  10 . 2  which are connected rigidly to the longitudinal supports and slope down steeply in the rearward direction, and a rear connecting tube  10 . 3 . This frame  10  may be used as a basic element for all the different types of lawn mower; however, it is also intended to reserve for the invention the possibility of providing different frame dimensions, it being possible for the frame, for its part, to be designed in modular fashion. 
     A motor bearing  12  in the form of arcuately curved rigid load-bearing plates is suspended on the longitudinal supports  10 . 1 . Pivot bearings  14  for the guide bar  16  are arranged at the rigid connection between the longitudinal supports  10 . 1  and the rear supports  10 . 2 , it being possible for the guide bar  16  to be pivoted about said pivot bearings and to be secured in each angular position in a manner known per se. The free ends of the longitudinal supports and rear supports are provided with axle bearings  18 . 1  and  18 . 2 . One of the longitudinal supports, moreover, bears a latching-adjustment mechanism  20  for the cutting-height adjustment. 
     FIG. 6 shows the running-gear and height-adjustment system  22  designed in the form of a module. According to the exemplary embodiment illustrated, the running gear has four running wheels  24 , of which the axle journals are connected in pairs, via radially running arms  26 , to in each case one axle  28 . 1 ,  28 . 2 . These axles are mounted rotatably in the axle bearings  18 . 1 ,  18 . 2 . The cutting height can be adjusted by rotation of the axle-bearing rod  28 . 1 ,  28 . 2  in its bearings  18 . 1 ,  18 . 2 . A simultaneous adjustment of the cutting height of the front wheels and rear wheels is effected by a link mechanism  30  which can be transferred into operative connection with the latching-adjustment mechanism  20 . 
     A motor unit can be firmly screw-connected to the motor bearing  12 . This motor unit may be designed as an internal combustion engine  32 . 1 , as a storage-battery motor unit  32 . 2  or as an electric motor  32 . 3 . The output shaft of the motor unit  32  bears the cutting unit (not illustrated in the drawing). 
     A hood  34  is secured on the frame  10 . A front apron  36  which is designed in the form of a module and can be secured on the frame, or is connected to the hood  34 , covers over the front-wheel suspension in the assembled state. It is possible for this hood  34  and the front apron  36  as well as a covering  38  which may additionally be provided for the motor unit, since they do not have to transmit any substantial forces, to be produced from relatively thin sheet-metal or plastic material. As can be seen, in particular, from FIG. 3, the hood  34  is equipped with air-channeling and/or grass-channeling passages  40 . The grass-collecting container  42  is designed as a further module, and this container can be fitted in in the rear region by means of its front hooks  44  and projects into the chaneling passage  40  by way of a guide plate  48  when the collecting container  42  is fitted on the frame  10 . The collecting container is provided with a pivotably articulated flap  46 . 
     The cutting unit (not illustrated in the drawing) may be designed as a blade which circulates in a horizontal plane and is fixed to the motor output shaft or can be coupled thereto as a module. This cutting unit, for its part, may be supported in a manner known per se by a bearing which is connected to the motor bearing  12 . Instead of the cutting unit, it is also possible for other tool subassemblies to be secured on the motor bearing  12  either in combined form with their drive motor or such that they can be coupled, as a module, to any desired drive motor. These operating subassemblies may be, for example, a verticutting arrangement, a sweeping device, a blower or some other device. 
     LIST OF DESIGNATIONS 
       10  Double delta frame 
       10 . 1  Longitudinal support 
       10 . 2  Rear support 
       10 . 3  Rear connecting tube 
       12  Motor bearing 
       14  Pivot bearing 
       16  Guide bar 
       18 . 1  Axle bearing front 
       18 . 2  Axle bearing rear 
       20  Latching-adjustment mechanism 
       22  Running gear 
       24  Running wheels 
       26  Radial arms 
       28 . 1  Axle front 
       28 . 2  Axle rear 
       30  Link mechanism 
       32 . 1  Internal combustion engine 
       32 . 2  Storage-battery motor unit 
       32 . 3  Electric motor 
       34  Hood 
       35  Cutting unit 
       36  Front apron 
       37  Verticutting unit 
       38  Covering 
       39  Sweeping unit 
       40  Air-channeling/grass-channeling passages 
       42  Grass-collecting container 
       44  Front hook 
       46  Flap 
       48  Guide plate