AU2006101054A4 - A towable machine tool attachment for vehicles - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION INNOVATION PATENT Invention Title: A towable machine tool attachment for vehicles The following statement is a full description of this invention, including the best method of performing known to me/us: N FIELD OF THE INVENTION OThe present invention relates to a towable machine tool attachment for a vehicle.

In particular, the invention is directed to a back-hoe attachment for a small earth moving vehicle such as a skid steer mini-loader.

BACKGROUND ART [Mere reference to background art herein should not be construed as an admission Sthat such art constitutes common general knowledge in relation to the invention.] SThe term "mini-loader" as used in the specification is intended to mean a small or S 10 compact ride-on skid-steer loader of the type described in Australian patent application Ono. 561,758 and petty patent no. 586,779. The disclosures of the aforementioned patent application and petty patent are incorporated herein by reference.

Such mini-loaders have found popular acceptance for small to medium earthmoving or earthworking tasks, particularly in confined areas. The mini-loaders are used primarily as front end loaders to scoop up soil at one location, and transport and dump it at another location. However, it is desirable to make the mini-loaders as versatile as possible by adapting them for use with other machine tool attachments.

One of the most common earthworking tasks is the digging of trenches or other excavations, and it is known to replace the scoop with an excavating mechanism, such as an hydraulically-operated excavating arm of the type found on backhoes. United States patent no. 4,117,944 describes a skid steer loader having an excavating mechanism mounted to the front end thereof. The excavating mechanism cannot be mounted at the back of the loader as the engine of the loader is housed at the rear thereof, and in any case, the operator's seat faces forward.

It is known to mount an excavating mechanism at the front end of the boom of the mini-loader of Australian patent application no. 561,758, in substitution for the loader bucket. Again, the excavating mechanism cannot normally be mounted at the rear of the mini-loader as a platform is provided at the rear of the mini-loader for a standing operator and a conventional mounting of the excavating attachment to the back of the mini-loader would obstruct or otherwise prevent the operator from mounting the platform.

It has been found that the mounting of an excavating mechanism at the front end of a skid steer loader or mini-loader has significant inherent disadvantages. First, as the excavating mechanism is substituted for the loader bucket, the mini-loader can only carry one such attachment at a time. It is therefore necessary of the operator to continually O change between loader bucket and excavator, depending on whether the machine is being used to excavate or transport the excavated soil. Since the two tasks are often alternated, it may be necessary for the operator to change between loader bucket and excavator a number of times during that job, thereby increasing the time and cost of carrying out that job. Furthermore, the mini-loader can only carry one of the attachments to the job site.

It is therefore necessary for the mini-loader to make a return journey to pick up the other attachment, or for an additional operator to transport that attachment to the job site.

_A second disadvantage of front mounted excavating mechanisms is the requirement for operators to sit on top of the machine while operating, necessitating rollover protection for safety reasons.

IC Australian petty patent no. 597,309 describes a mini-loader with an excavating mechanism mounted to the rear and to one side of the mini-loader. Although this excavating mechanism can be operated in conjunction with the scoop, it requires stabilising legs when in use, hindering mobility. Further, the excavating mechanism is mounted directly on the mini-loader, restricting the operator's free space and manoeuvrability.

Although towable machine tools are known, they consist mainly of machine tools mounted on trailers. A substantial disadvantage of such trailer-mounted devices is that they are pivotable about a vertical axis at the point of connection to the towing vehicle, allowing the trailer to swing from side to side, and to 'jack-knife' when reversing. This undesirable action severely limits manoeuvrability.

It is an aim of this invention to provide a towable machine tool attachment which overcomes or ameliorates one or more of the disadvantages or problems described above, or which at least provides a useful alternative.

SUMMARY OF THE INVENTION In one broad form, the invention provides a wheeled attachment suitable for connection to the rear of a towing vehicle, such as a mini-loader. The wheeled attachment comprises a platform supported on at least one wheel. Typically, the platform is supported on a pair of spaced castor wheels, each castor wheel being freely rotatable about a vertical axis for travel, but able to be locked in position relative to that vertical axis.

The platform is adapted to have a machine tool mounted thereto. Typically, the machine tool is an hydraulically operable excavator mechanism so that the combination O of vehicle and attachment can be used as a back-hoe. However, the platform can be used to mount other machine tools, such as a crane jib or trenching tool.

The wheeled attachment also comprises a mounting member adapted to be Sconnected to the towing vehicle. Preferably, the mounting member is fixed to the towing vehicle such that the mounting member is unable to yaw, i.e. pivot about a vertical axis, relative to the towing vehicle when connected thereto. In one embodiment, the mounting member has a pair of laterally spaced connection means for connection to the towing _vehicle.

_The mounting member is hinged to the platform and is pivotable relative to the platform about a transverse, substantially horizontal, hinge axis in use. This allows the N, platform to follow undulations as the vehicle travels, and the wheels to remain in contact with the ground.

The wheeled attachment also comprises means for pivoting the platform relative to the mounting member, to thereby raise and lower the platform in use. Preferably, the pivoting means comprises at least one hydraulic actuator which is able to lock the platform relative to the mounting member about the hinge axis. In this manner, the platform is stabilised for operation of the machine tool.

In order that the invention may be more readily understood and put into practice, one or more embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a right hand side view of the preferred embodiment of the present invention.

Figure 2 shows a left hand side view of the preferred embodiment of the present invention.

Figure 3 shows a rear view of the preferred embodiment of the present invention.

Figure 4 shows an elevation view of the preferred embodiment of the present invention.

DESCRIPTION OF PREFERRED EMBODIMENT As shown in the drawings, a wheeled attachment 10 is adapted to be connected to, and towed behind, a vehicle (not shown) in use. The wheeled attachment 10 is particularly adapted to be connected to the rear footplate of a skid steer mini-loader of the N type described in Australian patent application no. 561,758 and petty patent no. 586,779, although the invention is not limited to such use.

The wheeled attachment 10 comprises a machine platform 11 which is supported on a pair of laterally spaced castor wheels 17 they are spaced in a direction transverse to the normal direction of travel of the towing vhicle).

The platform 11 forms a base, frame, chassis or similar structure on which a machine tool 20 can be mounted. In the illustrated embodiment, the machine tool 20 is _an excavating mechanism. The platform 11 also has a footplate 1 lA on which an operator may stand to operate the machine tool.

I 10 The platform 11 is hinged to a mounting member 12 by a swivel or hinge pin 13.

The hinge pin 13 allows relative pivotal movement between the platform 11 and the mounting member 12 about a single axis, which in use, is substantially horizontal. (The hinged connection between the platform 11 and the mounting member 12 may comprise multiple hinges with a common hinge axis, and the term "swivel or hinge pin 13" is intended to cover a composite hinge pin formed by one or more axially aligned hinge pins).

In the illustrated embodiment, the mounting member 12 has two laterally spaced arms 12A, 12B which are connectable to the towing vehicle. The spaced arms 12A, 12B are preferably fixed rigidly to the towing vehicle, e.g. by bolts or pins. Alternatively, in some applications, the spaced arms 12A, 12B may each be pivotally connected to the towing vehicle, e.g. by removable pin connectors.

As the arms 12A, 12B are connected to the towing vehicle at laterally spaced locations, they prevent pivotal movement between the mounting member 12 and the towing vehicle about a vertical axis, i.e. they prevent the wheeled attachment from yawing relative to the towing vehicle. The wheeled attachment 10, once connected to the towing vehicle, is thereby constrained to travel in substantially the same direction as the towing vehicle. This facilitates reversing of the towing vehicle with the wheeled attachment connected thereto, and eliminates jack-knifing.

Other suitable connection arrangements may be used to connect the mounting member 12 to the towing vehicle such that there is no substantial relative movement between the mounting member and the towing vehicle about a vertical axis.

Two laterally spaced hydraulic actuators 14 are provided for vertical adjustment of the position of the platform 11. Each hydraulic actuator 14 has one end attached to a respective arm 15 fixed to the platform 11, and its other end connected to the mounting N member. The hydraulic actuators 14 enable the angle between the platform 11 and the mounting member 12 to be varied. The platform 11 can therefore be raised or lowered independently of the mounting member. Moreover, the hydraulic actuators 14 can be locked hydraulically to fix the angle between the platform 11 and the mounting member 12, so that the platform 11 is locked in position relative to the mounting member 12, and hence relative to the towing vehicle.

The hydraulic actuators 14 are powered by a hydraulic pump, typically mounted on the towing vehicle, and suitably connected to the hydraulic actuators 14 by hydraulic _hoses via a manually operable control valve on an operating console or control panel 28 on the platform 11. The hydraulic actuators 14 may be hydraulic cylinders.

,I If the hydraulic actuators 14 are extended, the platform 11 and the mounting member move apart in an arc about a common axis defined by the hinge pin 13, thereby swinging the machine platform 11 in an upwards motion off the ground. If the hydraulic actuators 14 are retracted, the platform 11 and the mounting member 12 move closer together in an arc about the common axis, thereby swinging the machine platform 11 in a downward motion towards the ground.

If the hydraulic pressure to the hydraulic actuators 14 is released, the platform 11 and the mounting member 12 are free to pivot about the horizontal axis defined by the hinge pin 13. This has the desirable effect of allowing the castor wheels 17 to remain in contact with the ground when the wheeled attachment 10 is being towed over undulating terrain.

Each castor wheel 17 is mounted to a wheel mount 18 whose upper end is joumrnalled in a respective wheel collar 16 fixed to the platform 11. Each castor wheel 17 has a 3600 range of motion as its wheel mount 18 can rotate within the corresponding wheel collar 16, but can also be locked into position at 900 intervals by locking its wheel mount 18 to the corresponding wheel collar 16, e.g. by locking pins. These two modes allow the castor wheels 17 to move freely when the wheeled attachment 10 is being towed, or locked into position for added stability when the machine tool 20 is in use. The use of castor wheels is particularly advantageous as the attachment 10 is unable to yaw relative to the towing vehicle. Accordingly, when the towing vehicle is turning or reversing, the castor wheels can pivot about a vertical axis to follow their line of travel.

The illustrated machine tool 20 comprises an excavating arm similar in construction to conventional excavators, but smaller in size. The excavating arm comprises two articulated portions 21, 22 and a scoop, bucket or other excavating tool 23 Ipivotally mounted at the distal end of the arm portion 22. The proximal end of arm portion 21 is pivotally mounted in a mounting bracket 30 which, in turn, is pivotally connected to the platform 11 so as to pivot about a vertical axis.

The horizontal or swing movement of the arm portion 21 is controlled by hydraulic cylinders 25, while hydraulic cylinder 24 is used to raise and lower the arm portion 21, as shown in Figure 3. The pivotal movement of distal arm 22 relative to proximal arm 21 is controlled using hydraulic cylinder 26; and the pivotal movement of _the excavating tool 23 relative to arm 22 is controlled by hydraulic cylinder 27. All of _the hydraulic cylinders 24, 25, 26, 27 are able to be controlled by respective manuallyoperable control valves on the console panel 28 which is mounted on the platform 11 and located at an approximate waist height for ease of operation.

It is to be understood that the terminology employed above is for the purpose of description and should not be regarded as limiting.

The foregoing embodiment is intended to be illustrative of the invention, without limiting the scope thereof. The invention is capable of being practised with various modifications and additions as will readily occur to those skilled in the art.

Accordingly, it is to be understood that the scope of the invention is not to be limited to the exact construction and operation described and illustrated, but only by the following claims which are intended, where the applicable law permits, to include all suitable modifications and equivalents within the spirit and concept of the invention.

For example, although the invention has been described with particular reference to its application to a back-hoe attachment for a mini-loader, it may also be applied, with suitable modification, for other machine tool attachments for other vehicles.

Furthermore, although the illustrated embodiment uses two castor wheels, a single central castor wheel may be used in some applications.

Throughout this specification, including the claims, where the context permits, the term "comprise" and variants thereof such as "comprises" or "comprising" are to be interpreted as including the stated integer or integers without necessarily excluding any other integers.

Claims (4)

1. A wheeled attachment suitable for connection to the rear of a towing vehicle, the wheeled attachment comprising a platform supported on at least one wheel, the platform being adapted to have a machine tool mounted thereto; a mounting member adapted to be connected to the towing vehicle, the mounting member being hinged to the platform and being pivotable relative to the platform about a transverse, substantially horizontal, hinge axis in use; and Imeans for pivoting the platform relative to the mounting member.

2. A wheeled attachment as claimed in claim 1, wherein the pivoting means comprises at least one hydraulic actuator, the hydraulic actuator being adapted to lock the platform relative to the mounting member about the hinge axis.

3. A wheeled attachment as claimed in claim 1 or 2, wherein the mounting member is adapted to be fixed to the towing vehicle such that the mounting member is unable to pivot about a vertical axis relative to the towing vehicle when connected thereto.

4. A wheeled attachment as claimed in any one of the previous claims, wherein the or each wheel is a castor wheel. A towable machine tool attachment for a mini-loader, comprising a frame supported on a pair of castor wheels, the frame having a machine tool, such as an excavator, mounted thereto; a mounting member having laterally spaced connection means for connection to the mini-loader such that the mounting member is unable to pivot about a vertical axis relative to the mini-loader when connected thereto, the mounting member being hinged to the frame and pivotable relative to the frame about a transverse, substantially horizontal, hinge axis in use; and hydraulic means for pivoting the frame relative to the mounting member, the hydraulic means being adapted to lock the platform relative to the mounting member.