Abstract:
A grass-cutting machine includes a mower unit ( 17 ) and a motive unit ( 10, 12, 14 ) having means whereby it may be mounted releasably on the mower unit ( 17 ), the motive unit including a rotatable trimmer head ( 14 ).

Description:
FIELD OF THE INVENTION  
         [0001]    This invention relates to grass-cutting machines.  
           [0002]    In most domestic gardens in the United Kingdom and in many other places around the world, grass cutting and collection is typically achieved by using a mower of some form to cut the grass and pick up the cuttings on the major part of a lawned area. On completion of this task, an additional tool may be used to trim the edges of the lawn and any areas which are inaccessible to the mower. This additional tool is likely to take the form of a trimmer incorporating a powered rotary nylon line or lines, a plastic safety blade or, in heavy-duty versions, a steel cutter blade.  
           [0003]    On occasions, the roles may be reversed, as the mower may be unable to cut excessively long grass and the trimmer will then be used first to cut back the long grass sufficiently to allow the mower to be used to complete the task and give a more uniform cut and a superior finish.  
           [0004]    It is an object of the present invention to provide a grass-cutting machine which is more versatile than the grass-cutting machines currently available.  
         SUMMARY OF THE INVENTION  
         [0005]    According to the present invention there is provided a grass-cutting machine comprising:  
           [0006]    a) a mower unit including a cutting blade, and  
           [0007]    b) a motive unit having means whereby it may be mounted releasably on the mower unit, the motive unit including means for driving the cutting blade,  
           [0008]    the motive unit also including, or having, means whereby it may be connected to, a rotatable trimmer head.  
           [0009]    The motive unit may include a handle which can be used to steer and propel the motive unit when separate from the mower to enable the motive unit to be used as a trimmer.  
           [0010]    The arrangement is preferably such that the handle can be used to steer the mower when the motive unit is mounted on the mower.  
           [0011]    In one embodiment of the invention the motive unit includes an electric motor and the handle includes a battery compartment for receiving batteries to power the electric motor.  
           [0012]    An electrical battery for supplying power to the electric motor may be mounted on the mower unit.  
           [0013]    The mower unit may have a housing which includes a hingedly mounted cover which can be fixed in a closed position and moved into an open position for mounting the motive unit on the mower unit and for removing the motive unit from the mower unit.  
           [0014]    The motive unit may include a first location plate, the mower unit may include a second location plate and means may be provided for releasably connecting the two location plates. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]    [0015]FIG. 1 shows a motive power unit attached to a handle,  
         [0016]    [0016]FIG. 2 shows a removable unit comprising a trimmer head attached in a fixed or releasable manner to the motive power unit of FIG. 1,  
         [0017]    [0017]FIG. 3 shows the removable unit of FIG. 2 installed on a mower,  
         [0018]    [0018]FIG. 3A shows different forms of location plates which can be used to mount the unit of FIG. 2 on a mower,  
         [0019]    [0019]FIG. 3B shows a modification to the arrangement of FIG. 3A,  
         [0020]    [0020]FIG. 3C shows a further modification to the arrangement of FIG. 3A,  
         [0021]    [0021]FIG. 4 shows a modification to the unit of FIG. 2,  
         [0022]    [0022]FIG. 5 shows the unit of FIG. 4 mounted on a mower,  
         [0023]    [0023]FIG. 6 shows a modification to the arrangement of FIG. 5,  
         [0024]    [0024]FIG. 7 shows a modification to the arrangement of FIG. 3, and  
         [0025]    [0025]FIG. 8 shows a further modification to the arrangement of FIG. 3. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0026]    As shown in FIG. 1, a motive power unit  10 , capable of imparting rotational movement to a drive shaft  11 , is attached to a handle  12  which is provided at its free end with a hand-grip formation  13 .  
         [0027]    The motive power unit  10  can be arranged to drive a trimmer head  14  mounted in a fixed or releasable manner on the drive shaft  11  and an arcuate guard or shield  15  can be fixed to the housing of the power unit  10 . As shown, the trimmer head  14  is of the type which includes a nylon line  16 , but it could be of the blade type.  
         [0028]    The assembly comprising the motive power unit  10  and the handle  12  (with or without the trimmer head  14 ), can be installed within a mower body  17 , as shown in FIG. 3. The mower body  17  includes a housing  18  and four wheels  19 , and there are permanently installed mower cutter blades (not shown) beneath the housing  18 . Drive from the motive power unit  10  may be permanently transmitted to the trimmer head  14  or the drive may be engaged and disengaged by, for example, a clutch, sliding gears, a separable coupling, separation of the trimmer head  14  from the motive power unit  10 , or other means.  
         [0029]    When the assembly comprising the motive power unit  10  and the handle  12  is installed within the mower body  17 , using suitable location and clamping devices as shown in FIGS. 3A, 3B and  3 C, drive can be transmitted to the mower blades (not shown) via an easily separable drive coupling, one part of which is installed on the motive unit  10  or trimmer head  14  (as applicable), with the other corresponding mating part being installed so as to drive the mower blades (not shown) directly or via a suitable transmission permanently installed within the mower.  
         [0030]    A suitable reduction transmission may be included within the mower to allow the use of mower cutting blades having a larger cutting width (diameter) than the trimmer head  14  and line, as these may require higher torque but not such high rotational speeds. The mower cutting blade may be arranged to rotate about a substantially vertical axis or, in the case of a cylinder mower, will be arranged to rotate about a substantially horizontal axis.  
         [0031]    As shown in FIG. 3A, the motive power unit  10  can be mounted on the handle  12  complete with a first location plate  20  formed with holes  21  to receive locating pillar pins  22  carried by a second location plate  23  mounted on the mower body  17 . A clamp support bracket  24  is mounted on the mower body  17  to provide secure support for the handle  12 . The assembly comprising the motive power unit  10 , handle  12  and first location plate  20  can be clamped in position by means of a cover  25  that, in use, is pressed down on top of the motive power unit  10  to clamp it in place. The cover  25  has a hinge  26  at one end and locking clasps or turnbuckle devices  27  at the other end. The cover  25  can be hinged open to allow removal of the motive power unit  10  with trimmer head  14  when so required.  
         [0032]    The device as a whole can thus be used as a wheeled trimmer, or as a mower or as a separate trimmer, depending on the task which the user wishes to carry out.  
         [0033]    [0033]FIG. 3B shows an arrangement similar to FIG. 3A, but differs therefrom in that the first location plate  20  carries a front slide latch or push-down sprung off-centre catch  28 . The latch or catch  28  is arranged for release by means of a lever on the motive power unit  10  or by means of a pull cable on the handle  12 .  
         [0034]    [0034]FIG. 3C shows a further arrangement similar to those of FIGS. 3A and 3B, but in this case the first location plate  20  carries three slide latches or push-down sprung off-centre catches  28 . The latches or catches  28  are arranged for release by means of a lever on the motive power unit  10  or by means of a pull cable on the handle  12 . In addition, a simple flanged collar  29  fitted over the handle  12  may be fixed by means of buckles  30  on top of the support bracket  24  on the body  17  of the mower.  
         [0035]    The motive power unit  10  may be an electric motor, a hydraulic motor, an internal combustion engine, a steam engine, a heat engine or other prime mover. Its position relative to the trimmer cutting head  14  may be varied as required. For example, if the motive power unit  10  is an internal combustion engine, it may be positioned at the end of the handle  12  opposite to the trimming head  14  and the separable coupling for connection to the mower cutter. If, on the other hand, the motive power unit  10  is an electric motor, it may be positioned, as shown, at the same end of the handle  12  as the trimming head  14 .  
         [0036]    [0036]FIG. 4 thus shows a motive power unit  10  which includes an electric motor which drives a trimming head  12 , with the power for the electric motor provided by means of a battery or a set of batteries contained within a battery compartment  31  contained within the handle  12  at the end thereof remote from the motive power unit  10 . The batteries within compartment  31  may supply electrical energy to the motor of unit  10  either on a long-term basis or on a short-term basis, i.e. when the assembly shown in FIG. 4 is removed from the mower for use as a trimmer. When the assembly of FIG. 4 is removed from the mower, the handle  12  is held by the user to steer and propel the trimmer. When the assembly of FIG. 4 is mounted on the mower, the handle  12  can be used to steer and propel the mower.  
         [0037]    When the assembly of FIG. 4 is installed within the mower, the mower could be powered by an on-board power supply, with the trimmer batteries recharged from the power supply on the motor. The on-board power supply may be in the form of a battery, a fuel cell or other electrical storage or generating device. The mower could alternatively be powered from an external supply, which also serves to recharge the batteries within compartment  31 . This refinement would allow the user short-term use of the trimmer unencumbered by any form of supply cable.  
         [0038]    [0038]FIG. 5 thus shows a mower which includes a battery  32  of substantial size which is mounted on the body  17  and is connected to the end of the handle  12  by means of a cable  33  to recharge the batteries within compartment  31  and/or to provide power to the motive power unit  10  to drive the motor blades. A link cable allowing stretch could also be used to allow continued use of the trimmer after the batteries in the handle compartment  31  are exhausted. There is a connector  34  at the end of the handle  12  (or at some other convenient position). This can be disconnected to enable the motive power unit  10  and the handle  12  to be removed from the mower and then run on the batteries contained within compartment  31 .  
         [0039]    As an alternative to the above, in the case of a mower with its own on-board electricity power supply or storage device, the battery compartment  31  could be omitted and a suitable stretchable link cable could be used instead.  
         [0040]    In the case of an electric motor drawing its power supply from a cable connected to a mains supply outlet, the motive unit  10  could be arranged as shown in FIG. 6. The assembly comprising the unit  10  and handle  12  can then be connected directly, or by means of a connector  34 , to the mains supply, and no link, cable or other connection to the mower would be necessary. Alternatively, a charger-type power supply transformer  35  could be incorporated within the handle  12  to recharge and/or bypass the batteries in the compartment  31 .  
         [0041]    A further embodiment is shown in FIG. 7 and includes a secondary motive power unit  36  permanently installed in the mower. The secondary motive power unit  36  drives the mower blades only when coupled to the primary motive power unit  10  which forms part of an assembly with the handle  12 , all as described above. There is a separable coupling  37  between the primary motive power unit  10  and the secondary motive power unit  36 . The coupling  37  can be a mechanical coupling (as shown) or an electrical coupling via a suitable shared mechanical transmission. The assembly comprising the primary motive power unit  10  and the handle  12  can thus be used in light-weight form for trimming and can also be combined with the secondary motive power unit  36  and the mower to produce increased power when installed within the mower to drive the mower blades.  
         [0042]    The mower unit may incorporate more than one set of mower blades in order to achieve greater cutting widths. This may be achieved by the use of a module comprising a single set of mower blades and a single removable motive power unit and/or trimmer combination, the module being duplicated the required number of times within an enlarged mower body to achieve the desired mower cutting width. This would result in there being more than one removable motive power unit and/or trimmer on one mower.  
         [0043]    Where only one removable motive power unit and/or trimmer head combination is required, the arrangement shown in FIG. 8 can be utilised. This includes a fixed handle  38  and a permanently installed motive power unit  39  arranged to drive a mower blade or blade set. The mower housing  17  has a width sufficient to accommodate two motive power units though, if an arrangement including two or more permanently installed motive power units  39  were required, the mower housing  17  would then be of correspondingly greater width. As shown, the handle  12  of the removable motive power unit can be connected to the fixed handle  38  by a connector  40  to provide a readily steerable handle assembly.  
         [0044]    The mower itself may be a wheeled mower, a hover mower, a mower mounted on rollers or other form of mower. It may be pedestrian-controlled and/or propelled or self-propelled or ride-on, as required. The mower may be capable of cutting the grass and collecting the grass cuttings as an alternative to only cutting the grass. For a mower having a facility for collecting the grass cuttings, many different ways of providing this facility may be utilised. For example, the cutting blade(s) of the mower could incorporate negative pressure or vacuum-generation means and suck up the grass cuttings into a suitable collection bag or container. Other means for this purpose include blades that create a sweeping motion or fan effect, sweeping brushes or blades powered by an additional motive unit or via a suitable transmission system.  
         [0045]    The mower may have one or more cutting blades of any suitable material or type. The mower may thus be a rotary mower, a cylinder mower, a reel mower, a flail mower or the like.