WO2014125466A1

WO2014125466A1 - A hitch

Info

Publication number: WO2014125466A1
Application number: PCT/IE2014/000003
Authority: WO
Inventors: Trevor Glenn CRUIKSHANK
Original assignee: Cruikshank Trevor Glenn
Priority date: 2013-02-13
Filing date: 2014-02-13
Publication date: 2014-08-21
Also published as: EP2955988A1

Abstract

A quick hitch (1) for attaching a tractor to an implement comprising a converter hitch (2), a headstock (3) attachable to the converter hitch (2) and mountable on an implement, a detachable power transmission (25) for transmitting power from a PTO shaft of a tractor to the headstock (3) and guides (35,36) for automatically guiding attachment of the detachable power transmission means, the quick hitch (1) being adapted to facilitate the rapid and safe four-point coupling and de-coupling of the converter hitch (2) fitted to the three point hitch of a tractor or similar vehicle to the headstock (3) fitted to an implement at its three-point mounting.

Description

A Hitch

Introduction This invention relates to a hitch for attaching a tractor to an implement and more particularly to a quick hitch for safely and quickly attaching implements to tractors such as farm tractors.

Background of the Invention

Tractor three-point hitches or linkages are well-known from the prior art. In general, three-point hitches are made up of two lower links and a top link adapted to couple to a counterpiece on an implement in a triangular arrangement. Where required, implements can then be powered by the PTO shaft of the tractor. Examples of the implements typically coupled to farm tractors include but are not limited to fertiliser spreaders, toppers, mowers, powerboxes and the like. Tractor drivers must frequently detach implements from and attach replacement implements to the three- point hitch of the tractor according to agricultural tasks to be undertaken. However, coupling and uncoupling of implements can be time consuming and dangerous. In addition, using known hitches and methods, such operations can frequently require a second person e.g. where the tractor driver controls the tractor and the three-point hitch from the cab of the tractor, the second person may be required to guide and attach the links to the implement counterpiece. Moreover, even where the coupling action is performed by the driver alone, the operation can be time consuming, laborious and dangerous. For example, the driver must often leave and return to the cab to move the tractor and/or the implement into the correct orientation for coupling or to actually couple the implement to the three-point hitch. In addition, space to the rear of the tractor is frequently cramped and some operations are of necessity performed with the tractor engine running so that significant safety risks arise. For example, in the event that the PTO shaft brake should fail or is accidentally released, the risk of injury is increased. Known coupling devices and methods also result in increased fuel consumption due to the increased time required to effect changeover of implements.

"Quick hitches" are also known. Quick hitches are intermediate devices attached to the three-point hitch adapted to make implement attachment easier. However, known quick hitches suffer from number of disadvantages. For example, known quick hitches are unsuitable for use with heavyweight implements. Moreover, known quick hitches suffer from a low fit tolerance such that a high degree of accuracy is required when connecting an implement to the quick hitch with the result that implement attachment can still be problematical and still result in the problems described above - particularly for operatives working alone.

Summary of the Invention

According to the invention there is provided a hitch for attaching a tractor to an implement comprising: a converter hitch;

converter hitch attachment means for attaching the converter hitch to a tractor;

a headstock attachable to the converter hitch and mountable on an

implement, and

power transmission means for transmitting power from a PTO shaft of a tractor through the converter hitch and the headstock to an implement.

Preferably, the converter hitch attachment means are attachable to the rear of a tractor. More preferably, the converter hitch attachment means comprises a three- point linkage attachable to a tractor three-point hitch.

Advantageously, the headstock is attachable to the converter hitch via a four-point headstock mounting. Preferably, the headstock comprises an implement three-point mounting for attaching the headstock to an implement.

Suitably, the power transmission means comprises a detachable coupling between the converter hitch and the headstock. Preferably, the coupling comprises a head for receiving a PTO shaft.

Advantageously, the coupling comprises a female-male connector.

Preferably, the female connector for detachably receiving the male connector is mounted on the converter hitch. More preferably, the female connector is pivotably mounted on the converter hitch. Preferably, the male connector for detachable insertion in the female connector is mounted on the headstock. More preferably, the male connector is pivotably mounted on the headstock. Suitably, the female connector comprises a female bore defined in the head for receiving a PTO shaft and the male connector comprises a male shaft on the headstock insertable in the female bore so that rotation of the tractor PTO shaft can be transmitted to the headstock. Advantageously, the female bore and the male shaft comprise guides for

automatically guiding the male shaft into the female bore.

Preferably, the guides comprise complimentary co-operable ribs in the female bore and the male shaft. More preferably, the ribs have sharpened or pointed ends.

Suitably, the male shaft is contiguous with an implement shaft for transmitting power to an implement.

Preferably, the implement shaft is insertable into a complimentary female part on the implement.

Optionally, the hitch further comprises means for effecting hydraulic communication between a tractor and an implement. Suitably, the hitch further comprises means for effecting electrical communication between a tractor and an implement.

The invention also extends to a power transmission means for transmitting power from a PTO shaft to an implement comprising:

a detachable female-male connector coupling;

a head on the coupling for receiving a PTO shaft;

the female connector comprising a female bore defined in the head oppositely disposable to a PTO shaft and the male connector having a male shaft insertable between the female bore and an implement so that rotation of the tractor PTO shaft can be transmitted via the male shaft to an implement, and

guides for automatically guiding the male shaft into the female bore and the implement. Preferably, the female connector is pivotable. More preferably, the male connector is also pivotable.

Suitably, the guides comprise complimentary co-operable ribs in the female bore and the male shaft.

Preferably, the ribs have sharpened or pointed ends.

The invention therefore contemplates a hitch for attaching a tractor to an implement comprising a converter hitch; attachment means on the converter hitch for attaching the converter hitch to a tractor; a headstock attachable to the converter hitch and mountable on an implement; detachable power transmission means for transmitting power from a PTO shaft of a tractor to the headstock, and guide means for automatically guiding attachment of the detachable power transmission means. The hitch is attachable to the rear of a tractor. Alternatively, the hitch can be attached to the front of a tractor. Preferably, the attachment means on the converter hitch is attachable to a tractor three-point hitch and the headstock is attachable to the converter hitch via a four-point hitch. The detachable power transmission means for transmitting power from a PTO shaft of a tractor to the headstock comprises a male-female coupling means adapted to articulate during coupling.

The male-female coupling means are pivotably mounted on the hitch for articulation during coupling and also facilitate toggling during coupling.

The guide means for automatically guiding attachment of the detachable power transmission means are formed on the male-female coupling means and comprise co-operable ribs and grooves on the male-female coupling means. The ribs have sharpened or pointed ends.

The invention also extends to a converter hitch as hereinbefore defined.

In a further embodiment, the invention also embraces a headstock as hereinbefore defined. The invention also extends to a tractor having a converter hitch as hereinbefore defined and an implement fitted with a headstock as hereinbefore defined.

Brief Description of the Drawings

The invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a perspective view from above and the implement side of a hitch accordance with the invention in the operating position with the converter hitch attached to the headstock and the implement on which the headstock is mounted omitted for clarity;

Figure 2 is a perspective view from above and the tractor side of the hitch of Figure 1 ;

Figure 3 is an enlarged perspective view of the implement shaft for transmitting power from the PTO shaft to the implement upon attachment of the headstock on the implement to the converter hitch;

Figure 4 is a perspective view from above and the implement side of the hitch of Figures 1 and 2 with the headstock partially detached from the converter hitch at the lower latch bars of the converter hitch; Figure 5 is a perspective view from above and the implement side of the hitch with the headstock fully detached from the converter hitch;

Figure 6 is a perspective view from above and the tractor side of the hitch with the headstock fully detached from the converter hitch;

Figure 7 is an exploded view from above and one side of the headstock and the converter hitch with enlarged views of the circled male shaft sleeve and male shaft of the headstock and of the PTO shaft coupling of the converter hitch;

Figures 8 to 11 are sequential side elevations of the converter hitch and the headstock moving from the detached position to the coupled operating position;

Figure 12 is an enlarged side elevation of the headstock and the converter hitch in the detached position;

Figure 13 is an enlarged front perspective view of the hitch in the coupled operating position from the implement side; Figure 14 is a front elevation of the hitch of Figure 13 with the headstock partially detached from the converter hitch at the lower latch bars of the converter hitch;

Figure 15 is a cross-sectional view of the hitch of Figure 14 along the line XV- XV of Figure 14; Figure 16 is a cross-sectional view of the hitch of Figure 14 along the line XVI- XVI of Figure 14;

Figure 17 is an enlarged view of the female hydraulic connectors of Figure 16 mounted on the hydraulic connector bar separated from the complimentary push-fit male hydraulic connectors on the converter hitch;

Figure 18 is a cross-sectional view of the hitch of Figure 14 along the line XVIII-XVIII of Figure 14;

Figure 19 is a perspective view from above and implement side of a

headstock of a second embodiment of a hitch of the invention in which the male shaft sleeve is fixedly mounted between the first and second support walls of the headstock;

Figure 20 is an implement side perspective view of the headstock of Figure

19;

Figure 21 is a tractor side perspective view of the headstock of Figure 19; Figure 22 is an implement side plan view of the headstock of Figure 19; Figure 23 is a cross-sectional view along the line XXIII-XXIII of Figure 22; Figure 24 is a perspective view from above and the implement side of a third simplified reduced cost embodiment of a quick hitch of the invention in which the electrical and hydraulic connectors and solenoid valves have been omitted but can be retro-fitted if desired;

Figure 25 is a perspective view from above and the implement side of the hitch of Figure 24 with the headstock fully detached from the converter hitch, and

Figure 26 is perspective view of the hitch of Figure 24 from the implement side.

Detailed Description of the Invention

As shown in Figures 1 to 18 of the drawings, a first embodiment of a quick hitch in accordance with the invention is generally indicated by the reference numeral 1 and is adapted to facilitate the rapid and safe four-point coupling and de-coupling of a converter hitch 2 fitted to the three point hitch of a tractor or similar vehicle to a headstock 3 fitted to an implement at its three-point mounting. The tractor and the implement have been omitted for clarity. However, the tractor can be any vehicle such as a farm tractor adapted for use with implements such as farm machinery and the like. Examples of such implements include but are not limited to toppers, mowers, fertiliser spreaders, powerboxes and the like.

The converter hitch 2 attachable to the three-point hitch of a tractor is made up of a substantially rectangular converter hitch frame 4 having a bottom wall 5, a first side wall 6 and a second side wall 7 upstanding from the bottom wall 5 and a top wall 8 extending between the side walls 6,7 parallel with the bottom wall 5. The frame 4 is further provided with centrally located parallel first and second spaced apart support walls 9,10 respectively extending between the bottom wall 5 and the top wall 8.

A first draft link mounting 11 for attachment to the three-point hitch of the tractor is provided adjacent the first side wall 6 between the first side wall 6 and the first support wall 9. Similarly, a second draft link mounting 12 for attachment to the three- point hitch of the tractor is provided adjacent the second side wall 7 between the second side wall 7 and the second support wall 10. A top link mounting 13 fitted with a hydraulic top link 14 for attachment to the top link of a tractor is provided on the top wall 8 of the converter hitch frame 4. The top link mounting 13 together with the first draft link mounting 11 and the second draft link mounting 12 in combination define a three-point linkage 15 to the tractor.

The converter hitch 2 of the quick hitch 1 is also provided with a four-point headstock mounting 16 for securely and rigidly coupling the converter hitch 2 to the headstock 3. The four-point headstock mounting 16 is made up of a first hydraulic latch mechanism 17 adjacent the first draft link mounting 11 , a second oppositely disposed hydraulic latch mechanism 18 adjacent the second draft link mounting 12, a first headstock support bar 19 on the top wall 8 of the converter hitch frame 4 adjacent the first side wall 6 and an oppositely disposed second headstock support bar 20 on the top wall 8 adjacent the second side wall 7. Accordingly, the converter hitch 2 engages with the tractor via a three-point linkage 5 and with the headstock 3 via four-point linkage mounting 16 to ensure ease and secure attachment of implements as shall be explained more fully below. The first and second hydraulic latch mechanisms 17,18 are made up of respective hydraulically controlled latch bars 21 ,22 moveable between open positions in which the latch bars 21 ,22 are recessed within their respective latch mechanisms 17,18 so that the headstock 3 can be placed against or removed from the converter hitch 2 and closed positions in which the headstock is secured to the converter hitch 2. In the closed positions, the latch bars 21 ,22 project from their respective latch mechanisms 17,18 and are securely inserted in respective latch bar receiving sleeves 23,24 on the side walls 6,7 respectively of the converter hitch 2.

The converter hitch 2 is further provided with a movable spring-loaded PTO shaft coupling 25 for engaging the PTO shaft of the tractor. The PTO shaft coupling 25 is pivotably and forwardly mounted towards the headstock 3 between the first and second support walls 9,10. At the tractor side, the PTO shaft coupling 25 is attachable to a PTO head 26 of a PTO shaft at a coupling socket 27 for receiving the PTO head 26. The PTO shaft coupling 25 is pivotably supported between the first and second support walls 9,10 on first and second sprung bars 28,29 either side of the PTO shaft coupling 25 so that the shaft coupling 25 can move and articulate.

The PTO shaft coupling 25 is prevented from pivoting excessively downwards by a stop plate 30 which extends between the PTO shaft coupling 25 and an upper transverse band 31 also disposed between the first and second support walls 9,10. The sprung bars 28,29 facilitate toggling of the pivotably supported PTO shaft coupling 25 during attachment of the headstock 3 to the converter hitch 2 as shall be explained more fully below. A male-female connector 32 is provided on the PTO shaft coupling 25 at the headstock side of the PTO shaft coupling 25. The male-female connector 32 serves as a power transmission means for transmitting power to the implement from the PTO shaft and is made up of a female bore 33 defined in the PTO shaft coupling 25 towards the implement and, as shall be explained more fully below, a male shaft 34 on the headstock 3 insertable in the female bore 33 so that rotation of the tractor PTO shaft can be transmitted to the headstock 3 via the PTO shaft coupling 25 of the converter hitch 2.

Internally, the female bore 33 is provided with elongate outwardly projecting ribs 35 and alternate grooves 35a oriented parallel with the longitudinal axis of the female bore 33 adapted to guide the male shaft 34 into the female bore 33 via

complimentary outwardly projecting shaft ribs 36 and alternate grooves 36a on the male shaft 34. The bore ribs 35 and the shaft ribs 36 are shaped to define pointed or sharpened tips at their meeting ends to further assist in automatically guiding the male shaft 34 into the female bore 33 when attaching an implement to the tractor. The toggling movement of the PTO shaft coupling 25 provides a forgiving tolerance to enable easy alignment of the male shaft 34 on the headstock 3 with the female bore 33 on the converter hitch 2 during coupling. The converter hitch 2 is further provided with four push-fit male hydraulic connectors 37 mounted on a hydraulic connector support bar 38 between the second side wall 7 and the second support wall 10 of the converter hitch frame 4. The hydraulic connectors 37 are communicable with the hydraulic system of the tractor via hydraulic cables (not shown). A valve control unit 39 together with solenoid control valves 40 control movement of hydraulic fluid to the hydraulic connectors 37 which assist in controlling implements fitted with the headstock 3 from the converter hitch 2 and in turn the tractor. A series of electrical connectors 41 for controlling lighting and the like on implements from the tractor is similarly located on an electrical connector support plate 42 mounted between the first side wall 6 and the first support wall 9 of the converter hitch frame 4.

The converter hitch frame 4 is also adapted for pallet for mounting if desired. More particularly, the first and second side walls 6,7 are each provided with bi-lateral pallet fork side mountings 65,66 respectively while the first and second support walls 9,10 are shaped on the implement side to define a pair of centrally located spaced-apart pallet fork mounting hooks 67,68 between the bi-lateral pallet fork side mountings 65,66. The headstock 3 is also frame-like in construction, rectangular in shape and dimensioned to couple with the converter hitch 2. The headstock 3 is made up of a base member 43, a first side member 44 upstanding from the base member 43, a second side member 45 upstanding from the base member 43 and a top member 46 extending between the side members 44,45 parallel with the base member 43. First and second hooks 47,48 are provided on the first and second side members 44,45 adjacent the top member 46 for mounting the headstock 3 on the converter hitch 2 at the first and second headstock bars 19,20 to create two points of the four-point mounting 16 via which the converter hitch 2 is attached to the headstock 3. Each side member 44,45 is also provided with respective first and second latch holes 49,50 adjacent the base member 43 through which the latch bars 21 ,22 of the converter hitch 2 can pass to into the latch bar receiving sleeves 23,24 on the converter hitch side walls 6,7 to securely couple the headstock 3 in position on the converter hitch 2 and complete the four-point headstock mounting 6 outlined above. Internally, the headstock 3 is provided with parallel inwardly curved first and second spaced apart centrally located support walls 51 ,52 respectively. The first and second support walls 51 ,52 extend between the headstock base member 43 and the headstock top member 46. The first and second support walls 51 ,52 are positioned to support a male shaft sleeve 53, which is a further component of the power transmission means, between the support walls 51 ,52 in a position aligned with the coupling socket 27 on the converter hitch 2. At the converter hitch 2 or tractor side, the male shaft sleeve 53 supports the male shaft 34 described above for transmitting power from the PTO shaft upon insertion in the female bore 33 of the male-female connector 32. The male shaft sleeve 53 is pivotably mounted between the support walls 51 ,52 on a transverse pivot pin 54 which extends between the support walls 51 ,52 so that the shaft sleeve 53 is free to articulate to facilitate ease of insertion of the male shaft 34 into the female bore 33. Excessive movement of the shaft sleeve 53 is limited by a limiting bracket 63 disposed over the shaft sleeve 53 and

connected at each end to the support walls 51 ,52 to which the male shaft sleeve 53 is connected at its top end via a finger 69 attached to the limiting bracket 63. The male shaft 34 is mounted within the male shaft sleeve 53 in a bearing 55 and extends through the shaft sleeve 53 to form a contiguous implement shaft 56 with the implement to transmit power from the PTO shaft to the implement upon attachment of the headstock 3 on the implement to the converter hitch 2. Like the male shaft 34, the implement shaft 56 can be provided with implement shaft ribs 57 and associated grooves 57a to facilitate insertion of the implement shaft 56 into a complimentary female part on the implement.

The headstock 3 is further provided with female hydraulic connectors 58 mounted on a hydraulic connector bar 59 disposed between the headstock second side member 45 and the second support wall 52 of the headstock 3. The female hydraulic connectors 58 are connectable to the push-fit male hydraulic connectors 37 on the converter hitch 2 to transmit power to the implement as required via implement side hydraulic connectors 60. Attachment of the headstock 3 to the converter hitch 2 prevents detachment of the hydraulic connectors. The hydraulic connectors 37,58 can be controlled from the tractor.

Both the male hydraulic connectors 37 on the converter hitch 2 and the

complimentary female hydraulic connectors 58 on the headstock 3 are spring mounted via respective springs 70,71 in the support bars 58,59 to assist in attaching and detaching the male and female hydraulic connectors 37,58.

Spring-loaded electrical contact connectors 61 are also provided on an electrical connector bar 61 disposed between the headstock first side member 44 and the first support wall 51. The electrical connectors 61 are positioned on the electrical connector bar 61 to be in electrical communication with the series of electrical connectors 41 when the headstock 3 is secured to the converter hitch 2.

The headstock 3 is also provided with an outwardly projecting limiting lug 64 on the first and second side members 44,45 disposed towards the converter hitch 2. The limiting lugs 64 abut the underside of the top wall 8 of the converter hitch frame 4 to prevent movement of the headstock 3 with respect to the converter hitch 2 and damage to the hydraulic connectors 37 and the like. On the implement side, the headstock 3 is provided with an implement three-point mounting 72 for attaching the headstock 3 to the three-point mounting to be found on most implements. The implement three-point mounting 72 is made up of two lower spaced apart side brackets 73,74 mounted on the base member 43 of the headstock and a centrally located top bracket 75 mounted on the top member 46 of the headstock 3.

In use, the converter hitch 2 of the quick hitch 1 of the invention is attached to the three point linkage of a tractor as previously described at the first draft link mounting 11 , the second draft link mounting 12 and the top link 14. Implements to be attached to the tractor via the converter hitch 2 can each be permanently fitted with a headstock 3 via the implement three-point mounting 72. Accordingly, in order to connect an implement fitted with a headstock 3 to the tractor 1 , a driver in the cab of a tractor must simply align the tractor/converter hitch 2 with the headstock 3 and manoeuvre the converter hitch 2 towards the stationary headstock 3 typically by reversing the tractor towards the headstock 3. When aligned, the converter hitch 2 can also be hydraulically raised and lowered as required by the driver from the cab of the tractor so that first and second hooks 47,48 of the headstock 3 are engaged with the corresponding headstock bars 19,20 on the converter hitch 3 and the first and second latch holes 49,50 on the headstock 3 are positioned so that the latch 5 bars 21 ,22 can pass through the first and second latch holes 49,50 and into the latch bar receiving sleeves 23,24 on the converter hitch to complete the four-point headstock mounting 16. The latch bars 21 ,22 are hydraulically actuated by the driver from within the tractor cab into the closed position and can be provided with warning buzzers and safety position limit switches if desired to indicate that the latch 10 bars 21 ,22 are not correctly locked in position.

The latch bars 21 ,22 can also be fitted with limit switches (not shown) to alert the driver that the latch bars are not in the closed position. 5 Due to the manner in which the spring-mounted coupling socket 27 and the male shaft sleeve 53 can pivot, articulate and toggle with respect to each other, the converter hitch 2 and the headstock 3 exhibit a high degree of tolerance in coupling - particularly in relation to the transmission of power from the PTO shaft though the quick hitch 1 of the invention to the implement. Moreover, as previously described,

>.o the ribs 35,36 and associated grooves 35a, 36a provided on the female bore 33 and the male shaft 34 act as guide means to guide the converter hitch 2 and the headstock 3 during coupling.

As will be appreciated by those skilled in the art, the hydraulic top link 14 allows 5 remote pitch adjustment of the quick hitch 1 from the tractor while the hydraulic locking latch bars 21 ,22 on the converter hitch 2 can be controlled from the tractor unit via a remote switch within the tractor so that once the locking latch bars 21 ,22 are in locked in position and the pitch of the quick hitch 1 set to the desired position the remote within the tractor can be switched to "Implement" so that the hydraulics system of the tractor can no longer control the top link 14 or the locking latch bars 21 ,22 for safety.

Figures 19 to 23 show a second embodiment of a quick hitch 1 of the invention broadly similar to the embodiment described in Figures 1 to 18 but in which the male shaft sleeve 53 of the headstock 3 is fixedly mounted between the first and second support walls 51 ,52 of the headstock 3 i.e. the pivot pin 54 is omitted. Like numerals indicate like parts.

More particularly, in the present embodiment, the male shaft sleeve 53 does not pivot i.e. the pivot pin 54 is omitted and the shaft sleeve 53 is fixedly mounted in a sleeve plate 76 rigidly mounted between the first and second support walls 51 ,52. However, as in the embodiment described in Figures 1 to 18, the PTO shaft coupling 25 is still pivotably mounted between the support walls 9,10 of the converter hitch 2 so that the PTO shaft coupling 25 is free to articulate to facilitate ease of insertion of the male shaft 34 into the female bore 33. Accordingly, in the present embodiment, articulation or pivoting movement of the PTO shaft coupling 25 alone allows for increased tolerance when attaching the converter hitch 2 to the headstock 3 on an implement in use. Figures 24 to 26 a third simplified and reduced cost embodiment of a quick hitch 1 of the invention broadly similar to the quick hitch described in Figures 1 to 18 but in which the hydraulic connectors 58, solenoid control valves 41 and the electrical connectors 61 have been omitted from the headstock 3. Like numerals indicate like parts.

The quick hitch 1 of Figures 24 to 26 is cheaper to manufacture than the

embodiments described in Figures 1 to 23 due to the omission of the aforementioned costly components and can therefore be sold at reduced cost. Nevertheless, the quick hitch 1 still provides an easy and secure method of attaching implements to a tractor. If desired, the hydraulic connectors 58, solenoid control valves 41 and the electrical connectors 61 can be retrofitted to the quick hitch 1 after purchase of the quick hitch 1. In a further embodiment of the invention, the implement three-point mounting 72 for attaching the headstock 3 to the three-point mounting implements can be adjustable vertically and horizontally so that the position of implements attached to the quick hitch 1 can be adjusted as required. The quick hitch 1 can be manufactured from any suitable material such as

galvanised laser cut mild steel and welded using conventional MIG welding techniques. Typical dimensions for the converter hitch 2 are 1269mm (W) x 79 mm (H) x 286mm (D) and for the headstock 3 are 1220mm (W) x 802mm (H) x 196mm (D). The quick hitch 1 of the invention facilitates the safe and easy automatic coupling of a tractor to a farm implement by a single user in a safe and efficient manner. It is not necessary for a driver to exit a tractor cab to perform a coupling operation thereby minimising labour costs and reducing time wasted when changing over implements. Fuel savings also result due to the speed with which the operation can be performed. In addition, the quick hitch 1 of the invention obviates the need for a driver to manually perform coupling operations in the vicinity of the PTO area of the tractor thereby significantly enhancing safety. In summary, the quick hitch 1 of the invention enjoys many advantages over the prior art. The hitch 1 of the invention significantly increases safety when attaching and detaching implements from a tractor - no risk of injury which arises from being positioned between the tractor and an implement. Moreover, it is not necessary to remove PTO shafts when changing implements.

The invention also allows for improved operator comfort as it is not necessary for an operator to leave his seat (e.g. in poor weather) to change implements. Ease of use also reduces operator stress levels. Efficiency is also increased due to the time saved changing implements e.g. it is calculated that an implement can usually be changed in less than 30 seconds.

One tractor and one operator can efficiently complete multiple tasks at reduced cost while fuel is not wasted during implement changeovers. The quick hitch 1 is suitable for use with all implements having a three-point hitch such as toppers, fertiliser spreaders, mowers, powerboxes and the like.

The invention is not limited to the embodiments herein described which may be varied in construction and detail without departing from the scope of the invention.

Claims

1. A hitch for attaching a tractor to an implement comprising:

a converter hitch;

a headstock attachable to the converter hitch and mountable on an

implement, and

2. A hitch as claimed in Claim 1 wherein the converter hitch attachment means are attachable to the rear of a tractor.

3. A hitch as claimed in Claim 1 or Claim 2 wherein the converter hitch attachment means comprises a three-point linkage attachable to a tractor three-point hitch.

4. A hitch as claimed in any of Claims 1 to 3 wherein the headstock is attachable to the converter hitch via a four-point headstock mounting.

5. A hitch as claimed in any of Claims 1 to 4 wherein the headstock comprises an implement three-point mounting for attaching the headstock to an implement.

6. A hitch as claimed in any of Claims 1 to 5 wherein the power transmission means comprises a detachable coupling between the converter hitch and the headstock.

5 7. A hitch as claimed in Claim 6 wherein the coupling comprises a head for receiving a PTO shaft.

8. A hitch as claimed in Claim 7 wherein the coupling comprises a female-male connector.

0

9. A hitch as claimed in Claim 8 wherein the female connector for detachably receiving the male connector is mounted on the converter hitch.

10. A hitch as claimed in Claimed in Claim 9 wherein the female connector is5 pivotably mounted on the converter hitch.

11. A hitch as claimed in Claim 9 or Claim 10 wherein the male connector for detachable insertion in the female connector is mounted on the headstock. o 12. A hitch as claimed in Claim 11 wherein the male connector is pivotably

mounted on the headstock.

13. A hitch as claimed in any of Claims 8 to 12 wherein the female connector comprises a female bore defined in the head for receiving a PTO shaft and the male connector comprises a male shaft on the headstock insertable in the female bore so that rotation of the tractor PTO shaft can be transmitted to the headstock.

14. A hitch as claimed in Claim 13 wherein the female bore and the male shaft 5 comprise guides for automatically guiding the male shaft into the female bore.

15. A hitch as claimed in Claim 14 wherein the guides comprise complimentary co-operable ribs in the female bore and the male shaft. 0

16. A hitch as claimed in Claim 15 wherein the ribs have sharpened or pointed ends.

17. A hitch as claimed in any of Claims 13 to 16 wherein the male shaft is contiguous with an implement shaft for transmitting power to an implement.

L5

18. A hitch as claimed in Claim 7 wherein the implement shaft is insertable into a complimentary female part on the implement.

19. A hitch as claimed in any of Claims 1 to 18 wherein the hitch further

D comprises means for effecting hydraulic communication between a tractor and an implement.

20. A hitch as claimed in any of Claims 1 to 19 wherein the hitch further comprises means for effecting electrical communication between a tractor and an implement.

21. A power transmission means for transmitting power from a PTO shaft to an implement comprising:

a detachable female-male connector coupling;

a head on the coupling for receiving a PTO shaft;

guides for automatically guiding the male shaft into the female bore and the implement.

22. A power transmission means as claimed in Claim 21 wherein the female connector is pivotable.

23. A power transmission means as claimed in Claim 21 or Claim 22 wherein the male connector is pivotable.

24. A power transmission means as claimed in any of Claims 21 to 23 wherein the guides comprise complimentary co-operable ribs in the female bore and the male shaft.

25. A power transmission means as claimed in Claim 24 wherein the ribs have sharpened or pointed ends.