NZ545845A - Trailer type mower - Google Patents

Abstract

A mower for towing behind a locomotive which includes a trailer frame (21), a number of rotary blades (10, 11, 14, 15) mounted to the trailer frame, and a number of corresponding motors (13, 17). Each of the rotary blades is mounted to rotate about an axis coaxial with an output shaft of a corresponding motor. A spindle (12) connects the rotary blade to the motor and the trailer via a self-aligning bearing (18) and a twine plate mounted around the spindle. The twine plate has a serrated inner surface adjacent the spindle to prevent plant material or other detritus from interfering with the bearing.

Description

NEW ZEALAND PATENTS ACT, 1953 No: 545845 Date: 10 Match 2006 COMPLETE SPECIFICATION TRAILER TYPE MOWER We, METALFORM (DANNEVIRKE) LIMITED, a company duly incorporated under the laws of New Zealand of Eastern Street, Dannevirke, New Zealand, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: Intellectual Property Office of N.z. 2 2 MAR 2007 545845 FIELD OF THE INVENTION The present invention relates to mowers for grass and other plants. In particular, the present invention relates to mowers of the type which are pulled behind a quad bike or other suitable vehicle.

BACKGROUND TO THE INVENTION Mowers for large areas are typically provided as a trailer that can be pulled behind a tractor or other suitable vehicle such as a quad-bike. Mowers provided as a trailer can cover greater areas in less time than ordinary lawn mowers of the type which are pushed by a pedestrian.

Typically, trailer type mowers have more than one rotary blade positioned adjacent to one other to provide the required area of coverage in a single pass. It is not desirable to use a single very large blade to provide a large cutting area because the torque required to drive such a large blade is much greater than in a multiple blade design.

The multiple rotary blades are driven by a single motor located on the trailer. The blades are connected to the motor by a gearing arrangement. The blades are therefore indirectly driven by the motor.

As a single motor is used to drive multiple rotary blades, a relatively high power motor is need. Fiorthermore, the gearing arrangement used to connect each of the blades to the motor is complicated. The gearing arrangement together with the motor represents the major portion of the cost of a trailer type mower.

It would be desirable to provide a trailer type mower with a reduced cost. Accordingly, it is an object of the present invention to provide a trailer type mower which will go someway towards meeting the above object or that will at least provide the public with a useful choice.

The term "comprising" as used in this specification means "consisting at least in part of. When interpreting each statement in this specification that includes the term "comprising", features other than that or those prefaced by the term may also be present. Related terms such as "comprise" and "comprises" are to be interpreted in the same manner.

SUMMARY OF THE INVENTION According to a first aspect the invention consists in a mower adapted for towing behind a locomotive comprising: a trailer frame; 545845$ - a corresponding plurality of motors, a motor coupled to each of the rotary blades wherein each of the rotary blades is mounted to rotate about an axis coaxial with an output shaft of a corresponding motor, and wherein a spindle connecting the rotary blade to the motor and the trailer via a self-aligning bearing, and a twine plate mounted around the spindle, the twine plate having a serrated inner surface adjacent to the spindle, the serrated inner surface preventing plant material or other detritus from interfering with the bearing.

Preferably, the mower further comprises a plurality of support bearings, a bearing coupled between each rotary blade and the trailer frame, the bearings protecting the motors from shock transmitted via the rotary blades. Preferably, the bearings are self-aligning bearings.

Preferably, the mower comprises two motors and two rotary blades. However, the mower may comprise more than two motors and two rotary blades.

Preferably, each rotary blade is mounted from said trailer frame by a spindle that is supported by a bearing engaged to the trailer frame.

Preferably, each bearing supports a respective axle in a direction transverse to the axis of rotation of the corresponding rotary blade to protcct the motor from at least some of any transverse forces applied to the rotary blade or the spindle.

According to a second aspect, the invention consists in a mower adapted for towing behind a locomotive, comprising: the rotary blade mounted to rotate about an axis coaxial with an output shaft of a corresponding motor; and a support bearing coupled between the rotary blade and the trailer frame, the support bearing protecting the motor from at least some of any forces transverse to the axis of rotation experienced by the rotary blade, and wherein a spindle connecting the rotary blade to the motor and the trailer via a self-aligning beating, and a twine plate mounted around the spindle, the twine plate having a serrated inner surface adjacent to the spindle, the serrated inner surface preventing plant material or other detritus from interfering with the bearing.

Preferably, the support bearing is a self-aligning bearing.

Preferably, the mower further comprises a second rotary blade, a corresponding second motor, mounted coaxial to the axis of rotation of the second rotary blade, and a second support bearing coupled between the second rotary blade and the second motor.

Preferably, each rotary blade is fixed to a respective spindle.

Preferably, the output shaft of each motor is fixed coaxially with a respective spindle. a trailer frame; a rotary blade mounted to the trailer frame, the rotary blade having an axis of rotation; 545845 To those skilled in the art to which the invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the scope of the invention as defined in the appended claims. The disclosures and the descriptions herein are purely illustrative and are not intended to be in any sense limiting.

BRIEF DESCRIPTION OF THE DRAWINGS An example of the present invention will now be described in detail with reference to the accompanying drawings, in which: Figure 1 is an exploded, perspective view from above of a motor in accordance with the present invention; Figure 2 is a perspective view from below of the motor of Figure 1; and, Figure 3 is a cross-sectional view of the motor of Figures 1 and 2.

DETAILED DESCRIPTION Figure 1 shows a mower in an exploded view from above. The mower comprises two pairs of rotary blades 10, 11, 14, 15 each mounted to a corresponding motor 13, 17which is coaxial with the axis of rotation of the blades. The blades are attached to spindles 12, 16 which each connect to a corresponding motor 13, 17. The pairs of blades are positioned adjacent to one another and slightly off set in a direction of motion of trailer as to provide overlapping coverage in the direction of motion of the trailer.

The trailer consists of a pair of wheels 20 mounted to a trailer frame 21. The rotation blades and motors are mounted to the trailer frame. The trailer frame is connected to a suitable vehicle, such a tractor or a quad bike, by a tow bar 22. The underside of the mower of Figure 1 can be more clearly seen in Figure 2. Figure 2 shows the mower fully assembled.

The rotating blades 10, 11 are coupled to the corresponding motor 13 by a spindle 12. The spindle is connected to the trailer via a self aligning bearing 18. The self aligning bearing allows the spindle to move a little relative to the trailer frame. This prevents any shocks suffered by the blades from damaging the spindle or motor. The blades may suffer shocks from collisions with objects such as stones, tree roots or curbs.

Self-aligning bearings are constructed with an inner assembly contained within an outer ring that has a spherical raceway. This construction allows the bearing to tolerate a small angular misalignment resulting from deflection or improper mounting. However, a self aligning bearing is just one example of a shock absorbing bearing that can be used in the present invention. Any suitable support bearing, such as a bush bearing, may be used. >^o«6atrf» w 545845 Figure 3 is ctoss-sectioiial view of the trailer mower shown in Figures 1 and 2. Figure 3 shows blades 10, 11 connected to spindle 12. The spindle is connected to the motor 13 using a bolt 25. Self aligning bearing 18 connects the spindle to the trailer frame 21.

A twine plate 23, 24 is mounted around the spindle for preventing the plant material from interfering with the bearing. This can be clearly seen in Figure 2. The twine plate is annular and has a serrated inner surface. Any plant material wrapped around the spindle is cut by the serrated inner surface. The twine plate accordingly prevents the plant material from interfering with the bearing.

In a multiple blade design, by using a dedicated motor, mounted coaxially with each of the rotating blades, lower power motors can be used and complicated gearing arrangements can be dispensed with. The result is that the mower can be produced at substantially reduced costs as compared with prior trailer type mowers.

As each motor is mounted directly to a rotary blade, each motor is vulnerable to the direct transfer of shock loads from the rotary blades. It is therefore desirable to include shock protection in the form of a support bearing between the motor and the corresponding rotary blades. The support bearing prevents damage to the motor in the event that the blades contact a hard object such as a curb or tree stump. It is particularly important to include such shock protection bearing in a trailer type mower, as compared with a normal pedestrian pushed mower, because trailer type mowers typically move at much greater speeds and therefore experience much greater shocks.

It is to be understood that the scope of the invention is not limited to the described embodiment and therefore that numerous variations and modifications may be made without so parting from the scope of the invention as set out in the specification. \ ^ .4§845

Claims (12)

1. A mower adapted for towing behind a locomotive comprising: a trailer frame; a plurality of rotary blades mounted for cutting, from the trailer frame; and a corresponding plurality of motors, a motor coupled to each of the rotary blades, wherein each of the rotary blades is mounted to rotate about an axis coaxial with an output shaft of a corresponding motor, and wherein a spindle connecting the rotary blade to the motor and the trailer via a self-aligning bearing, and a twine plate mounted around the spindle, the twine plate having a serrated inner surface adjacent to the spindle, the serrated inner surface preventing plant material or other detritus from interfering with the bearing.

2. A mower according to claim 1, further comprising a plurality of support bearings, a bearing coupled between each rotary blade and the trailer frame, the bearings protecting the motors from shock transmitted via the rotary blades.

3. A mower according to claim 1 or claim 2, wherein the bearings are self-aligning bearings.

4. A mower according to claim 2 or claim 3 wherein each bearing supports a respective axle in a direction transverse to the axis of rotation of the corresponding rotary blade to protect the motor from at least some of any transverse forces applied to the rotary blade or the spindle.

5. A mower according to any one of the preceding claims, wherein the mower comprises two motors and two rotary blades.

6. A mower according to any one of the preceding claims, wherein each rotary blade is mounted from said trailer frame by the spindle that is supported by a bearing engaged to the trailer frame.

7. A mower according to claim 6, wherein each rotary blade is fixed to a respective spindle.

8. A mower according to claim 7, wherein the output shaft of each motor is fixed coaxiallv with a respective spindle. 1674663_2 54J58.45

9. A mower adapted for towing behind a locomotive, comprising: a trailer frame; a rotary blade mounted to the trailer frame, the rotary blade having an axis of rotation; the rotary blade mounted to rotate about an axis coaxial with an output shaft of a corresponding motor; and a support bearing coupled between the rotary blade and the trailer frame, the support bearing protecting the motor from at least some of any forces transverse to the axis of rotation experienced by the rotary blade, and wherein a spindle connecting the rotary blade to the motor and the trailer via a self-aligning beating, and a twine plate mounted around the spindle, the twine plate having a serrated inner surface adjacent to the spindle, the serrated inner surface preventing plant material or other detritus from interfering with the bearing.

10. A mower according to claim 9, wherein the support bearing is a self-aligning bearing.

11. A mower according to claim 9 or claim 10, further comprising a second rotary blade, acorresponding second motor, mounted coaxial to the axis of rotation of the second rotary blade, and a sccond support bearing coupled between the second rotary blade and the second motor.

12. A mower substantially as described herein with reference to the accompanying drawings 1674663_2