[0001] This invention relates generally to a particular configuration of electric tractor.

Summary of the Disclosure

[0002] There is provided herein an electric tractor having a particular chassis configuration affording versatility and ease-of-use advantages for hobby farming, light industry and the like.

[0003] The tractor comprises a pair of parallel spaced apart bogies comprising a battery power supply and an electric drive componentry for respective drive wheels thereof.

[0004] Rearward bracing structurally interconnects the bogies, preferably arched thereover.

[0005] Furthermore, a pair of pivotally coupled booms extent forward of the bracing and have respective linear actuators at proximal ends thereof for raising and lowering the booms and mechanical device attachment coupling at distal ends thereof.

[0006] Such sparse tractor chassis allows space between the bogies and the booms suitable for the attachment of various operational accessories and operation thereof which may include a carryall deck that fits between the bogies for carrying of produce and the like, buckets, forklift tines, rotary hoes, flail mowers, power harrows and the like.

[0007] The bogies may allow 1500 mm therebetween, thereby allowing for the carrying of standard sized pallets (typically approximately 1200 mm across) therebetween. As such, for example, a fruit picker may be hoisted by the booms and place produce within pallets held between the bogies.

[0008] Furthermore, the sparse tractor chassis allows for the operation of mechanical attachments both from between the bogies or from behind. In embodiments, the tractor may support a seat which may position behind the bracing, (especially suitable for providing counterweight) or in front of the

1 bracing (especially suitable for close oversight of operation of mechanised attachments).

[0009] Furthermore, the lightweight and low centre of gravity construction of the tractor provides for versatility in the operation and capabilities of the tractor.

[0010] The configuration of the booms and linear actuators preferably allows for lifting of 300 kg or more through over 1700 mm of travel, despite the tractor weighing approximately 250 kg or less.

[0011] The battery supply may have sufficient capacity to run the tractor for up to 3 days during normal use. In this regard, the battery supply may comprise lithium iron phosphate batteries each between 1 - 6 kwh. Electric motors of the electric drive componentry may be fully involved 2 kW electric motors driving the drive wheels via worm drive transmission.

[0012] The bogies may be substantially rectangular in cross-section and the electric drive componentry may be substantially unobtrusively entirely concealed within boundaries of the structural chassis of each bogey. In embodiments, replaceable rechargeable batteries interconnect through sockets exposed by the bogies, such as through an upper surface thereof .

[0013] Other aspects of the invention are also disclosed.

Brief Description of the Drawings

[0014] Notwithstanding any other forms which may fall within the scope of the present invention, preferred embodiments of the disclosure will now be described, by way of example only, with reference to the accompanying drawings in which:

[0015] Figure 1 shows a perspective view of an electric tractor in accordance with an embodiment;

[0016] Figure 2 shows a top plan view of the electric tractor in accordance with a further embodiment;

[0017] Figure 3 shows a front elevation view of the tractor of Figure 2;

2 [0018] Figure 4 shows a side elevation view of the tractor of Figure 2;

[0019] Figure 5 shows a side elevation view of the electric tractor having a flail mower attachment;

[0020] Figure 6 shows a side elevation view of the tractor comprising a power harrower attachment in accordance with an embodiment;

[0021] Figure 7 shows a perspective view of the electric tractor comprising a forklift tine attachment;

[0022] Figure 8 shows a top plan view of the electric tractor comprising the forklift tine attachment;

[0023] Figure 9 shows a perspective view of the electric tractor comprising a rotary hoe assembly attachment;

[0024] Figure 10 shows a top plan view of the electric tractor of Figure 9 ;

[0025] Figure 11 shows a perspective view of the electric tractor comprising a bucket attachment; and

[0026] Figure 12 shows a perspective view of the electric tractor comprising a carryall deck attachment.

Description of Embodiments

[0027] Figure 1 shows an electric tractor 100 comprising a pair of parallel spaced apart elongate bogies 101. Each body 101 may comprise a structural chassis 102 supporting a battery power supply 103 an electrical drive componentry 104 for respective drive wheels 105 thereof. The electrical drive componentry 104 may comprise a DC electric motor supplied by the battery power supply 103 and turning worm drive gearing. The DC electric motor may be a 48 V 2kw electric motor.

[0028] Electric drive componentry 104 may unobtrusively fit within the cross- sectional boundaries of the structural chassis of each bogey 101.

[0029] The electrical drive componentry 104 is controlled by a controller 106 which, in embodiment shown comprises a joystick control device and associated inputs and indicators.

3 [0030] Each bogey 101 may comprise one drive wheel 105 which may be located at a forward end of the bogey 101. With reference to the orientation of Figure 2, forward, distal and the like will be described as being towards the of the left of the illustration and rearward, proximal and the like will be described as being towards the right of the illustration.

[0031] The electrical drive componentry 104 may control the drive wheels 105 in a skid-steer manner wherein each drive wheel 105 is operated independently to turn the tractor 101 or synchronously to drive the tractor 101 forward or rearward.

[0032] With reference to Figure 6 the drive wheel 105 turns a caterpillar track 107 which may be supported by a sub-bogey assembly 108 of a horizontal arrangement of bearing wheels 109 and tensioning wheels 110. In accordance with this embodiment, the drive wheel 105 may be cogged to engage an interior surface of the caterpillar track 107.

[0033] In embodiment shown in Figure 5, the drive wheel 105 is rotationally independent and wherein the rear of each bogey 101 supported by a castor wheel 111. The drive wheel 105 may be pneumatic in this embodiment.

[0034] The bogies 101 structurally interconnected by rearward arched bracing 112. The bracing 112 may comprise a pair of vertical posts 113 extending vertically from respective bogies 101 and a horizontal crossbeam interconnecting upper ends of each post 113.

[0035] The truck 100 further comprises a pair of pivotally coupled booms 115 extended forward from the bracing 112. Respective linear actuators 116 interface proximal ends of the booms 115 to raise and lower the booms 115. The linear actuator is 116 are preferably electromechanical linear actuator s 116 drawing power from the battery supply 103. The configuration of the booms 115 and the linear actuators 116 may allow lifting of 300 kg at distal ends thereof which may be more than the weight of the entire tractor 100 (which may be approximately 250 kg). Furthermore, the configuration of the booms

4 115 and the linear actuators 116 may allow distal ends of the booms 112 to raise through approximately 1700 mm or more.

[0036] The booms 115 comprise mechanical device attachment coupling at distal ends thereof for the attachment of various mechanical devices.

[0037] The coupling may comprise respective connections brackets 117 coupling engagements 118 (shown in Figure 4) of an attached mechanical device.

[0038] Various passive mechanical devices may be attached, including the bucket 119 shown in Figure 1 , the forklift tine assembly 120 shown in Figure 2, the carryall deck 121 shown in Figure 12 in the rotary hoe assembly 127 shown in Figure 9.

[0039] Each boom 115 may comprise a distal linear actuator 122 acting on linkages 123 to tilt the pivotally coupled connections brackets 117. In this way, the bucket attachment 119 may be tilted up or down and, so too may the tines 124 of the forklift tine assembly 120.

[0040] The distal linear actuators 122 similarly preferably electromechanical linear actuators powered by the battery supply 103.

[0041] With reference to Figure 12, the carryall deck 121 may comprise a rearward section 125 that is generally elongate and which fits between the bogies 101 along substantially the entire length thereof and a forward section 126 which extends beyond the booms 115 and which may widen. In accordance with this embodiment, the rear of the carryall deck 121 may be pivotally coupled to the bracing 112 or the bogies 101 and the forward end thereof couple to the booms 115 such that the lifting of the booms 115 corresponding the lifts a front edge of the carryall deck 121.

[0042] In alternative embodiments, the carryall deck 121 may fit between the bogies 101 only, that is, not extend substantially beyond the front of the booms

115.

5 [0043] With reference to Figure 9, the rotary hoe assembly 127 may comprise an arrangement of plough discs 128, blades 129 and hoe wheels 130. Similarly, raising or lowering the booms 115 may control the operational depth of the rotary hoe assembly 127 and the operation of the distal linear actuators 122 may control the operational pitch thereof.

[0044] The coupling may further interconnect powered devices, including the flail mower 131 shown in Figure 5 and the power harrow 132 shown in Figure 6.

[0045] These power devices may be driven by an electric motor 133. The electric motor 133 is preferably direct drive and draws power from the power supply 103.

[0046] The battery power supply 103 may comprise plug-in replaceable rechargeable batteries 134. In embodiment shown in Figure 5, the plug-in replaceable batteries 134 may plug into electrical connections sockets through an upper surface of at least one of the bogies 101. Power cabling may supply power from batteries 134 of one bogey 101 to the other bogey 101 or, alternatively, each bogey 101 may comprise respective one or more batteries 134.

[0047] The batteries 134 preferably lithium iron phosphate and may each have 1 - 6 kWh capacity.

[0048] The controller 106 may be rearwardly accessible to allow for walk- behind operation of the tractor 100.

[0049] In embodiments, the tractor 100 comprises a seat 135. The seat 113 may support a foot support brace 136.

[0050] In embodiment shown in Figure 1 , the seat 135 may position rearward of the bracing 112 or, in embodiment shown in Figure 9, the seat 112 may locate forward of the bracing 112.

[0051] In a preferred embodiment, the seat 112 is interchangeably configurable rearward or forward of the bracing 112. In accordance with this embodiment,

6 the seat 135 may be supported from a horizontal swingarm 137 which may allow the seat to swing rear of the bracing 112 in the manner shown in Figure 1 or in front of the bracing 112 in the manner shown in Figure 9. The controller 106 may be connected to the seat 135 so that the controller 106 is accessible at either position.

[0052] The tractor 100 may comprise boom position sensors to determine the position of each boom 115. During operation, the controller 106 may control the booms 115 synchronously (or, independently in embodiments) depending on a sense the position from the boom position sensors.

[0053] Similarly, the tractor 100 may comprise distal linear actuator position sensors to determine the linear extent of the distal linear actuators 122. As such, the controller 106 may control the attachment according to the position of the connection brackets 117.

[0054] In embodiments, the controller 106 is programmed with preprogrammed modes of operation and wherein the controller 106 automatically control the positioning of the booms 115 (and, in embodiments, the positioning of the distal linear actuator is 122) depending on the mode of operation. For example, depending on the attachment attached to the booms 115 (and which may be specified by a relevant input of the controller 106, or by electrical coupling between the mechanical attachment and the booms 115), the controller 106 may control the booms 115 depending on the particular type of attachment and the various operational modes thereof. For example, where the carryall deck 121 is attached, the controller 106 may inhibit the maximum height 115 of the booms 115.

[0055] Furthermore, the controller 106 may comprise operational safeguard control wherein, for example, the electric motor 133 driving the flail mower 131 is inhibited when the booms 115 lifted.

[0056] The controller 106 may further comprise electronic speed governing to limit the travel speed of the tractor 100, such as to 14 km/h.

7 [0057] The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the invention. However, it will be apparent to one skilled in the art that specific details are not required in order to practise the invention. Thus, the foregoing descriptions of specific embodiments of the invention are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed as obviously many modifications and variations are possible in view of the above teachings. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the following claims and their equivalents define the scope of the invention.

[0058] The term “approximately” or similar as used herein should be construed as being within 10% of the value stated unless otherwise indicated.

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