AU2012207038A1 - Hitch assembly - Google Patents

Abstract

A hitch assembly for connecting a first and second vehicle at a height above the ground, comprising: a base for connecting to the first vehicle; a tow mount for connecting to the second vehicle; a first member pivotably connected to the base at a first pivot, and pivotably connected to the tow mount at a second pivot ; and a second member pivotably connected to the base at a third pivot, and pivotably connected to the tow mount at a fourth pivot, wherein in use, the pivotable connections allow relative movement between the tow mount and the base such that the height of the tow mount above the ground is variable relative to the height of the base above the ground, and wherein the first, second, third and fourth pivots have respective pivot axes separately located to control the orientation of the tow mount; and wherein the trailer hitch assembly further comprises a stop to limit relative movement of the base and the tow mount.

Description

P/00/01i1 Regulation 3.2 AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Invention Title: Hitch assembly The following statement is a full description of this invention, including the best method of performing it known to us: 2 Hitch Assembly Field of the invention The present invention relates to a hitch assembly for connecting two vehicles. A particular application of the hitch assembly includes use as a trailer hitch for connecting a trailer 5 to a motor vehicle. However, it is to be appreciated the hitch assembly may be used to connect other types of vehicles. Background of the invention To increase transportation capacity, it has been known to connect two or more vehicles together. Typically a towing vehicle, such as a tractor, truck, car, or other automobile will tow a 10 trailing vehicle such as a trailer. To connect the towing vehicle and trailing vehicle, a tow hitch is typically used, that allows articulation between the two vehicles. It is important, especially during towing operations, that a suitable tow hitch configuration is used so that both vehicles are substantially level with the ground. If the tow hitch configuration is not properly matched, one vehicle may exert undue upward or downward 15 force on the other connected vehicle through the tow hitch. This may cause, for example, the trailer to be angled forwards, or backwards, which will affect load capacity, handling of the vehicles, as well as general safety. To accommodate vehicles of differing heights, tow hitches have been configured to alter the height of the tow coupling. It has also been known to provide adjustable hitch supports, so 20 that an operator can set the tow hitch to a suitable height to match the towing vehicle and trailer. Reference to any prior art in the specification is not, and should not be taken as, an acknowledgment or any form of suggestion that this prior art forms part of the common general knowledge in Australia or any other jurisdiction or that this prior art could reasonably be expected to be ascertained, understood and regarded as relevant by a person skilled in the art. 25 Summary of the invention In a first aspect, there is provided a hitch assembly for connecting a first and second vehicle at a height above the ground, comprising: a base for connecting to the first vehicle; a tow 3 mount for connecting to the second vehicle; a first member pivotably connected to the base at a first pivot, and pivotably connected to the tow mount at a second pivot; and a second member pivotably connected to the base at a third pivot, and pivotably connected to the tow mount at a fourth pivot, wherein in use, the pivotable connections allow relative movement between the tow 5 mount and the base such that the height of the tow mount above the ground is variable relative to the height of the base above the ground, and wherein the first, second, third and fourth pivots have respective non-aligned pivot axes to control the orientation of the tow mount; and wherein the trailer hitch assembly further comprises a stop to limit relative movement of the base and the tow mount. 10 Advantageously, the stop provides a limit to which the tow mount can move with respect to the base. This prevents extreme relative height differences between the first vehicle and second vehicle, which may otherwise allow excessive tilting of the second vehicle. This extreme tilting may occur, for example if the operator is not careful in checking the weight distribution and balance of either one of the vehicles before adjusting the tow mount relative to the base. 15 Thus the stop may provide an important safety mechanism to prevent damage to the vehicles. In one form, the stop is operable to limit the minimum height of the tow mount above the ground to be substantially equal to the height of the base above the ground. Advantageously, this may prevent the second vehicle from angling forward past a horizontal configuration of the second vehicle. 20 In one form, the stop is operable by limiting pivotal movement of the first and/or second member relative to the respective base and/or tow mount. In a further form, a portion of the base defines the stop. In one form, the hitch assembly further comprises a lock, wherein the lock is selectively engagable to prevent relative movement of the base and the tow mount. Advantageously, this 25 allows the operator to lock the tow mount relative to the base. This may be used when the operator determines the tow mount and base are at the optimum relative height configuration. In one form, the lock is engagable when the position of the tow mount relative to the base is defined by the stop. Advantageously, this allows the lock to be easily engaged when the tow mount and base are at the position limited by the stop. This reduces difficulties in engaging a 4 lock where the operator may otherwise need to simultaneously align the tow mount and base, whilst trying to engage the lock. This feature has particular advantage if the operator needs to engage the lock whilst the vehicles are connected. In one embodiment, when the lock is engaged, the hitch assembly is in a horizontal 5 configuration such that at least one of the first or second members is horizontal. Advantageously, when the hitch assembly is used for towing the horizontal member is substantially under tension only, with minimal bending moments. In one form, the lock includes; one or more base locking apertures in the base; and a lock pin, wherein the lock is selectively engagable by passing the lock pin through at least one of the 10 base locking apertures, the lock pin limiting pivotal movement of at least one of the first or second members relative to the base. In a further form, one of the first and second members further includes one or more member locking apertures, wherein the lock is selectively engagable by passing the lock pin through at least one of the member locking apertures. 15 In another form of the hitch assembly, the stop and engaged lock cooperatively prevent relative movement of the base and the tow mount. In one form of the hitch assembly, the configuration of the first and second members causes the tow mount to maintain a substantially constant orientation relative to the base during relative movement between the base and the tow mount. Advantageously, this may allow the 20 tow coupling, such as a tow ball, to maintain a constant orientation when the tow mount is moved. This ensures the tow hitch can maintain articulation properties without being constrained by the configuration of the tow hitch assembly. In one form of the hitch assembly, the pivots are arranged such that straight lines from the first pivot to second pivot, second pivot to third pivot, third pivot to fourth pivot, and fourth 25 pivot to first pivot substantially form a parallelogram. In another form of the hitch assembly, the pivots are arranged such that straight lines from the first pivot to second pivot, second pivot to third pivot, third pivot to fourth pivot, and fourth pivot to first pivot substantially form a trapezoid.

5 In yet another form of the hitch assembly, the pivots are arranged such that straight lines from the first pivot to second pivot, second pivot to third pivot, third pivot to fourth pivot, and fourth pivot to first pivot substantially form a quadrilateral. In one form, the hitch assembly further comprises a second stop, wherein in use, the 5 second stop limits a maximum height difference between the height of the tow mount above the ground and the height of the base above the ground. In one form, the base further comprises a projection, wherein in use, the projection is interconnected with a receiver of the first vehicle. In another form, the base is fixed to a drawbar of the first vehicle. 10 In one form, the tow mount comprises of an aperture for mounting any one of a tow ball, tow hook, tow eye, tow pin, tow jaw or tow pintle. In another aspect, there is provided a hitch assembly for connecting a first vehicle and second vehicle at a height above the ground, comprising: a base for connecting to the first vehicle; a tow mount for connecting to the second vehicle; a first member pivotably connected to 15 the base at a first pivot, and connected to the tow mount; wherein in use, the pivotable connection allow relative movement between the tow mount and the base such that the height of the tow mount above the ground is variable relative to the height of the base above the ground; and wherein the trailer hitch assembly further comprises of a stop to limit movement of the tow mount relative to the base. 20 In one form, the stop limits the minimum height of the tow mount above the ground to be substantially equal to the height of the base above the ground. In one form, the hitch assembly further comprises a lock, wherein the lock is engaged to prevent relative movement of the base and the tow mount. In a further form, the lock is engagable when the tow mount and base are limited by the stop. 25 In another aspect, there is provided a hitch assembly for connecting a first and second vehicle at a height above the ground, comprising: a base for connecting to the first vehicle; a tow mount for connecting to the second vehicle; a first member pivotably connected to the base at a first pivot, and pivotably connected to the tow mount at a second pivot; and a control element to 6 control the orientation of the tow mount relative to the base; wherein in use, the pivotable connections allow relative movement between the tow mount and the base such that the height of the tow mount above the ground is variable relative to the height of the base above the ground, and wherein as the height of the tow mount is progressively raised relative to the base, the 5 control element progressively tilts the tow mount from an upright orientation to tilted orientation towards the second vehicle. In one form of the hitch assembly, the control element is connected to the base at a third pivot, and pivotally connected to the tow mount at fourth pivot, wherein the first, second, third and fourth pivots have respective non-aligned pivot axes, and wherein the distance between the 10 first pivot and second pivot is greater than the distance between the third pivot and fourth pivot. Preferably, the degree of tilt of the tow mount is such that the relative orientation of a tow bar connected to the tow mount is substantially maintained throughout the range of relative movement. For example, if the tow bar extends at 900 to the axis of the tow ball, then this orientation is substantially maintained, even when the tow mount is in the raised position. 15 As used herein, except where the context requires otherwise, the term "comprise" and variations of the term, such as "comprising", "comprises" and "comprised", are not intended to exclude further additives, components, integers or steps. Further aspects of the present invention and further embodiments of the aspects described in the preceding paragraphs will become apparent from the following description, given by way 20 of example and with reference to the accompanying drawings. Brief description of the drawings Fig. I is a cross-sectional side view of the hitch assembly in the horizontal configuration and in the raised configuration; Fig. 2 is a cross-sectional side view of the hitch assembly of Fig. 1 in the locked 25 horizontal configuration; Fig. 3 is a cross-sectional side view of the hitch assembly of Fig. I in the raised configuration; Fig. 4 is a top view of a base of the hitch assembly; 7 Fig. 5 is a side view of the base of Fig. 2; Fig. 6 is a top view of a first member of the hitch assembly; Fig. 7 is a side view of the first member of Fig. 4; Fig. 8 is a top view of a second member of the hitch assembly; 5 Fig. 9 is a side view of the second member of Fig. 6; Fig. 10 is a is a top view of a tow mount of the hitch assembly; Fig. 11 is a side view of the tow mount of Fig. 10; and Fig. 12a to 12d illustrates a sequence of loading a boat to a trailer connected by a hitch assembly to an automobile. 10 Detailed description of the embodiments Figs. 1 to 3 illustrates a hitch assembly I for connecting two vehicles, comprising a base 3 for connecting to a first vehicle, and a tow mount 5 for connecting to a second vehicle. A first member 7 is pivotably connected to the base 3 at a first pivot 9, and pivotably connected to the tow mount 5 at a second pivot 11. A second member 13 is pivotably connected to the base 3 at a 15 third pivot 15, and pivotably connected to the tow mount 5 at a fourth pivot 17. The pivotable connections allow relative movement between the tow mount 5 and the base 3 whilst providing a connection therebetween. As shown in Fig. 1, the tow mount 5, when in use, can be moved from a horizontal configuration, as illustrated in Fig. 2, to a raised configuration, as illustrated in Fig. 3, such that the height above the ground would be greater 20 than the height of the base 3 above the ground. The pivots 9, 11, 15 and 17 are separately located, so that the orientation of the tow mount 5 relative to the base 3 is controlled, dependent on the degree of relative movement between the tow mount 5 and the base 3. In particular, the first member 7 and second member 13 act as linkages to provide a predetermined orientation of the tow mount 5 relative to the 25 assembly 1, as the tow mount 5 and base 3 are displaced to one another. For example, the tow mount may maintain its orientation with the tow ball 23 maintained in a substantially upright 8 orientation, throughout the range of relative movement. The base 3 is further provided with a stop 19 which limits pivotal movement of the first member 7, thereby preventing the tow mount 5, when in use, to move to a position beyond the horizontal configuration where the height of the tow mount 5 above the ground is less than the height of the base 3 above the ground. A lock 21, 5 when engaged locks the hitch assembly in the horizontal configuration as illustrated in Fig. 2, as will be explained in further detail below. In the raised configuration as illustrated in Fig. 3, a second stop in the form of second web 41 limits the maximum height difference between the tow mount 5 and base 3. The stop 19 may also function to stop movement of first member 7 to the maximum height difference. 10 The components of the hitch assembly 1 will now be described in detail. Referring to Figs. 4 and 5, the base 3 has a projection 31, and projection locking apertures 33. The projection 31 is in the form of a rectangular hollow section, and adapted to be received in a receiver of the first vehicle. The receiver also be in the form of a rectangular hollow section acting as a socket for the projection 31. The projection locking aperture 33 is provided for a lock pin (not shown) 15 or other locking mechanism to retain the projection 31 in the receiver of the first vehicle. This may be achieved by providing a locking aperture on the receiver that is, in use, aligned with projection locking apertures 33 to allow the lock pin to pass through. The lock pin may be retained to the assembly 1, by lock wire or cotter pin, or as part of a bolt and nut combination, or as a self retaining detent pin. 20 The base further comprises of side flanges 35, 37 connected by a first web 39, a second web 41, and stop 19. The side flanges 35, 37 are provided with first pivot apertures 43 for the first pivot 9, and third pivot apertures 45 for the third pivot 15. The pivot apertures are adapted to receive a pivot pin to form the respective pivots. The side flanges 35, 37 are also provided with base locking apertures 47 for receiving a 25 lock pin 22 of the lock 21. The first member 7 will now be described with reference to Figs. 6 and 7. The body 51 of the first member 7 is formed from flat bar, and provided with first and second pivot apertures 53 and 55 for the first and second pivots 9, 11 respectively. The pivot apertures are formed by welding (pipe like) hollow bar sections to the body 51, the bar sections forming collars around 9 the pins of the respective pivots. The first member 7, further comprises member locking aperture 57 for the lock 21, formed similarly to the first and second pivot apertures 53, 55. The second member 13 will now be described with reference to Figs. 8 and 9. The body 61 is formed from a flat bar, and provided with third and fourth pivot apertures 63 and 65 for the 5 third and fourth pivots 15, 17 respectively. The pivot apertures of the second member 13 are formed similar to the pivot apertures of the first member 7, but with the hollow bar sections welded to the ends of the body 61. In one embodiment, the second member 13 is shorter than the first member 7. With such geometry, as the tow mount 5 is progressively moved to the raised configuration, the shorter 10 second member 13 causes to tow mount 5 to progressively tilt towards the second vehicle. Accordingly, the axis of the tow ball 23 tilts from the upright position to a rearwardly inclined position. Advantageously, this tilt corresponds to the tilt angle of the second vehicle as the tow mount 5 is raised. This allows the tow ball 23, and a socket receiving the tow ball on the second vehicle to substantially maintain the same relative angular displacement. This assists in towing 15 operations by maintaining the two articulating elements (tow ball 23 and socket receiving the tow ball) near the middle of their mutual relative range of movement. The tow mount 5 will now be described with reference to Figs 10 and 11. The tow mount 5 comprises of two side flanges 71, 73 interconnected to the tow mount body 75. The side flanges 71, 73 are provided with second pivot apertures 77 for the second pivot 11, and fourth 20 pivot apertures 79 for the fourth pivot 17. A tow aperture 81 is provided in the tow mount body 75 for mounting a tow ball 23, as illustrated in Figs. 1 to 3, or any other suitable towing coupling such as a tow hook, tow eye, tow pin, tow jaw or tow pintle, or shackle. The operation of the hitch assembly I will now be described. During normal towing operations, such as driving on the roads, the hitch assembly 1 will be selectively locked in the 25 horizontal configuration as illustrated in Fig. 2, by passing a lock pin 22 passing through base locking apertures 47 (see Figs. 3 and 5) and member locking aperture 57 (Figs. 6 and 7) to form lock 21. This is ensure the height of the tow mount 5 does not vary during driving, thereby providing better handling, driving control and safety. This would also prevent the second vehicle, such as a trailer from changing angles whilst driving.

10 When loading the second vehicle, it may be desirable to have the second vehicle at an angle to assist in loading. The lock 21 is disengaged by removing the lock pin 22, thereby allowing the tow mount 5 to move relative to the base 3. Depending on the weight distribution of the load on the second vehicle, the tow mount 5 may be biased to the raised configuration, 5 horizontal configuration, or neutral. If the weight distribution of the load tips the second vehicle rearwardly, then the tow mount is biased to the raised configuration. The second vehicle, having an angle, may then be conveniently loaded. During loading, the weight distribution of the second vehicle may change, and bias the tow mount 5 back to the horizontal configuration. The hitch assembly I may then be easily 10 locked in the horizontal configuration by passing the lock pin 22 through the locking apertures 47, 57 of lock 21. When the tow mount 5 is in the horizontal configuration limited by the stop 19, the lock 21 can be easily engaged without having to manually adjust the position of the tow mount 5 to align the locking apertures 47, 57. An example of operating the hitch assembly 1 will now be described with reference to 15 Figs. 12a to 12d. In this example the vehicle assembly 1000 comprises a car 100 and a boat trailer 200 connected by hitch assembly 1. The boat trailer 200 is adapted to receive a boat 300. When the boat trailer 200 is unloaded, the weight distribution biases the boat trailer 200 to the horizontal configuration. Referring to Fig. 12a, the vehicle assembly 1000 without the boat 300 is driven to the 20 boat recovery site with the boat trailer 200 locked in the horizontal configuration. Before recovering the boat 300, the lock 21 is disengaged. As the weight distribution biases the boat trailer to the horizontal configuration, the trailer retains the horizontal configuration. The vehicle assembly 1000 may then be further manoeuvred, such as reversing down a boat ramp, or beach. Advantageously, the horizontal configuration allows reversing of the vehicle assembly 1000 with 25 reduced risk of the boat trailer 200 being caught into the ground. Once in the recovery location, the boat 300 is advanced toward the boat trailer 200. The weight of the boat 300 at the rear of the trailer 200 changes the weight distribution towards the rear of the trailer, causing the tow mount 5 to be biased to the raised position, as illustrated in Fig. 12 b. This changes the angle of the boat trailer 200 to advantageously assist in loading the 30 boat 300 onto the boat trailer 200.

11 Fig. 12c illustrates the boat 300 winched further onto the boat trailer 200. Fig. 12d illustrates the boat 300 winched onto the boat trailer 200, whereby the weight of the boat has further been redistributed onto the trailer 200, such that the trailer biases the hitch assembly I to the horizontal configuration. The lock 21 is then engaged, and the vehicle 5 assembly may be driven away. The hitch assembly I may be fabricated from any suitable material having high strength and rigidity. For example steel, aluminium, titanium, iron, fibre reinforced polymer, etc can be used. In one embodiment, at least some of the components are formed from commercially available rectangular hollow steel sections, steel bar, and steel angles cut and welded to form. 10 The described embodiment of the hitch assembly is merely one embodiment, and it is to be appreciated other embodiments, variations and modifications are possible. In one variation, the lock may further comprise of multiple locking portions to enable the hitch assembly to limit pivotal movement at more than one position. This allows the operator to select more than one different relative height for the tow mount. In another variation, the stop 15 may be adjustable. This allows the user to select a desired limit for the movement of the tow mount relative to the base. It will be understood that the invention disclosed and defined in this specification extends to all alternative combinations of two or more of the individual features mentioned or evident from the text or drawings. All of these different combinations constitute various alternative 20 aspects of the invention.

Claims (23)

1. A hitch assembly for connecting a first and second vehicle at a height above the ground, comprising: - a base for connecting to the first vehicle; 5 - a tow mount for connecting to the second vehicle; - a first member pivotably connected to the base at a first pivot, and pivotably connected to the tow mount at a second pivot ; and - a second member pivotably connected to the base at a third pivot, and pivotably connected to the tow mount at a fourth pivot, 10 wherein in use, the pivotable connections allow relative movement between the tow mount and the base such that the height of the tow mount above the ground is variable relative to the height of the base above the ground, and wherein the first, second, third and fourth pivots have respective pivot axes separately located to control the orientation of the tow mount; and wherein the trailer hitch assembly further comprises a stop to limit relative movement of 15 the base and the tow mount.

2. A hitch assembly according to claim 1, wherein the stop limits the minimum height of the tow mount above the ground to be substantially equal to the height of the base above the ground.

3. A hitch assembly according to any previous claim, wherein the stop is operable by 20 limiting pivotal movement of the first and/or second member relative to the respective base and/or tow mount.

4. A hitch assembly according to claim 3, wherein the base comprises the stop, which limits, pivotal movement of the first and/or second member relative to the base.

5. A hitch assembly according to any preceding claim, further comprising a lock, 25 wherein the lock is engaged to prevent relative movement of the base and the tow mount.

6. A hitch assembly according to claim 5, wherein the lock is engagable when the tow mount and base are limited by the stop.

7. A hitch assembly according to either claim 5 or 6, wherein the lock comprises; - one or more base locking apertures in the base; and 13 - a lock pin, wherein the lock is engaged by passing the lock pin through at least one of the base locking apertures, the lock pin limiting pivotal movement of at least one of the first or second members relative to the base. 5

8. A hitch assembly according to claim 7, wherein the first or second members further comprises of one or more member locking apertures, wherein if the lock is engaged, the lock pin passes through at least one of the member locking apertures.

9. A hitch assembly according to claim 6, wherein the stop and engaged lock cooperatively prevents relative movement of the base and the tow mount.

10 10. A hitch assembly according to any one of the preceding claims wherein the configuration of the first and second members causes the tow mount to maintain a substantially constant orientation relative to the base during relative movement between the base and the tow mount.

11. A hitch assembly according to any preceding claim, wherein the pivots are 15 arranged such that straight lines from the first pivot to second pivot, second pivot to third pivot, third pivot to fourth pivot, and fourth pivot to first pivot substantially forms a parallelogram.

12. A hitch assembly according to any one of claims 1 to 9, wherein the pivots are arranged such that straight lines from the first pivot to second pivot, second pivot to third pivot, third pivot to fourth pivot, and fourth pivot to first pivot substantially forms a trapezoid. 20

13. A hitch assembly according to any one of claims 1 to 9, wherein the pivots are arranged such that straight lines from the first pivot to second pivot, second pivot to third pivot, third pivot to fourth pivot, and fourth pivot to first pivot substantially forms a quadrilateral.

14. A hitch assembly according to any one of the preceding claims, further comprising a second stop, wherein in use, the second stop limits a maximum height difference 25 between the height of the tow mount above the ground and the height of the base above the ground. 14

15. A hitch assembly according to any preceding claim, wherein the base further comprises a projection, wherein in use, the projection is received and connected to a receiver of the first vehicle.

16. A hitch assembly according to any one of claims I to 14, wherein the base is fixed 5 to a drawbar of the first vehicle.

17. A hitch assembly according to any preceding claim, wherein the tow mount comprises of an aperture for mounting any one of a tow ball, tow hook, tow eye, tow pin, tow jaw or tow pintle.

18. A hitch assembly for connecting a first vehicle and second vehicle at a height 10 above the ground, comprising: - a base for connecting to the first vehicle; - a tow mount for connecting to the second vehicle; - a first member pivotably connected to the base at a first pivot, and connected to the tow mount; 15 wherein in use, the pivotable connection allow relative movement between the tow mount and the base such that the height of the tow mount above the ground is variable relative to the height of the base above the ground; and wherein the trailer hitch assembly further comprises of a stop to limit movement of the tow mount relative to the base. 20

19. A hitch assembly according to claim 18, wherein the stop limits the minimum height of the tow mount above the ground to be substantially equal to the height of the base above the ground.

20. A hitch assembly according to either claim 18 or 19, further comprising a lock, wherein the lock is engaged to prevent relative movement of the base and the tow mount. 25

21. A hitch assembly according to claim 20, wherein the lock is engagable when the tow mount and base are limited by the stop.

22. A hitch assembly for connecting a first and second vehicle at a height above the ground, comprising: - a base for connecting to the first vehicle; 15 - a tow mount for connecting to the second vehicle; - a first member pivotably connected to the base at a first pivot, and pivotably connected to the tow mount at a second pivot; and - a control element to control the orientation of the tow mount relative to the base; 5 wherein in use, the pivotable connections allow relative movement between the tow mount and the base such that the height of the tow mount above the ground is variable relative to the height of the base above the ground, and wherein as the height of the tow mount is progressively raised relative to the base, the control element progressively tilts the tow mount from an upright orientation to tilted orientation 10 towards the second vehicle.

23. A hitch assembly according to claim 22, wherein the control element is connected to the base at a third pivot, and pivotally connected to the tow mount at fourth pivot, wherein the first, second, third and fourth pivots have respective pivot axes separately located, and wherein the distance between the first pivot and second pivot is greater than the distance between the 15 third pivot and fourth pivot.