AU2011213825A1 - Quick Hitch Assembly - Google Patents

Description

1 QUICK HITCH ASSEMBLY FIELD OF THE INVENTION 5 The present invention relates to a quick hitch assembly for attaching implements to a boom or arm of a carrier or vehicle. BACKGROUND TO THE INVENTION 10 Implements conventionally fitted to heavy machinery include those suitable for loading, working or carrying loads such as a bucket, dipper bucket, fork lift unit, hydraulic shovel, grader, drill unit, ripper, scarifier, etc. Conventionally, the implements are fitted to the heavy machinery by manually inserting large cast steel pins through holes in plates formed on the implements and in the operating arms of the machinery. This is a time 15 consuming and tedious process. The operator must also alight from the controls of the vehicle or carrier or employ the services of an assistant to attach the implement. To rectify this, quick hitch assemblies have been proposed. These assemblies normally enable the connection of the implement to the heavy machinery to be effected 20 automatically by the operator, that is, without the need to alight from the controls of the machinery. None, however, is completely satisfactory for one reason or another. For instance, one common type of quick hitch system requires significant modification of the bucket to enable the quick hitch system to be fitted. Once modified, the bucket cannot then be used by any other front end loader which does not have the same quick fit 25 assembly. More importantly however, modification of the bucket in the first place is a long and costly exercise. Another quick hitch assembly which has been proposed has a hydraulically activated hook. A significant disadvantage of this hitch is that if the hydraulic pressure drops and/or 30 there is a break in one of the hydraulic lines, the implement may become detached. Quick hitch devices of the prior art have reduced the time and effort otherwise needed to exchange implements on a carrier. Nevertheless, the quick hitch devices of the prior art are designed to engage only those implements having mounting pins which are spaced 2 apart a specific distance. Unfortunately, in practice, all implements do not have a uniform spacing between the mounting pins. In such cases, the operator is forced to either not use the quick coupling device in regard to these implements or have additional quick coupling devices available to accommodate pins of different spacings. Difficulties in using quick 5 hitch assemblies may also arise if different implements have different size pins that connect to the quick hitch assembly. Additionally, due to the affects of wearing and differences in manufacturing tolerances, the quick coupling devices often loosely grip the implement to be operated. Such 10 looseness in the connection not only causes the implement to suffer premature wearing, but also increases the risk of an unintended release of the implement. As can be appreciated, this can create a very dangerous situation for the workmen involved. In regard to certain implements, such as an impact hammer, the looseness in the connection can also hamper the ability of the operator to properly position the implement. 15 It is an object of the present convention to provide a quick hitch assembly that overcomes or least ameliorates one or more of the above-mentioned disadvantages, or at least provides a commercial alternative. 20 BRIEF DESCRIPTION OF THE INVENTION In a first aspect, the present invention provides a quick hitch assembly for attaching an implement to a boom of a carrier or vehicle, the quick hitch assembly comprising - attachment means for attaching the quick hitch assembly to a boom of a carrier or a 25 vehicle, - a first coupling for receiving an implement mounting pin, - a second coupling for receiving an implement mounting pin, the second coupling including a fixed portion that is fixed relative to the quick hitch assembly and a movable portion that is movable relative to the quick hitch assembly, 30 - an engagement member movable between an engaged position in which the engagement member engages with the movable portion of the second coupling to prevent movement of the movable portion of the second coupling relative to the quick hitch assembly and a disengaged position in which the engagement member is positioned clear of the movable 3 portion of the second coupling and the second coupling is able to move relative to the quick hitch, and - drive means for selectively driving the engagement member between the engaged position and the disengaged position, 5 - wherein the engagement member includes a visual indicator visible to an operator of the carrier or vehicle from an operating position of the carrier or vehicle to provide visual indication as to whether the engagement member is in the engaged position or the disengaged position. 10 In a second aspect, the present invention provides a quick hitch assembly for attaching an implement to a boom of a carrier or vehicle, the quick hitch assembly comprising - attachment means for attaching the quick hitch assembly to a boom of a carrier or a vehicle, - a first coupling for receiving an implement mounting pin, 15 - a second coupling for receiving an implement mounting pin, the second coupling including a fixed portion that is fixed relative to the quick hitch assembly and a movable portion that is movable relative to the quick hitch assembly, - an engagement member movable between an engaged position in which the engagement member engages with the movable portion of the second coupling to prevent movement 20 of the movable portion of the second coupling relative to the quick hitch assembly and a disengaged position in which the engagement member is positioned clear of the movable portion of the second coupling and the second coupling is able to move relative to the quick hitch, - drive means for selectively driving the engagement member between the engaged 25 position and the disengaged position, and -biasing means for biasing the engagement member into the engaged position in the event of failure of the drive means. In a third aspect, the present invention provides a quick hitch assembly for attaching an 30 implement to a boom of a carrier or vehicle, the quick hitch assembly comprising - attachment means for attaching the quick hitch assembly to a boom of a carrier or a vehicle, - a first coupling for receiving an implement mounting pin, 4 - a second coupling for receiving an implement mounting pin, the second coupling including a fixed portion that is fixed relative to the quick hitch assembly and a movable portion that is movable relative to the quick hitch assembly, - an engagement member movable between an engaged position in which the engagement 5 member engages with the movable portion of the second coupling to prevent movement of the movable portion of the second coupling relative to the quick hitch assembly and a disengaged position in which the engagement member is positioned clear of the movable portion of the second coupling and the second coupling is able to move relative to the quick hitch, 10 - drive means for selectively driving the engagement member between the engaged position and the disengaged position, - -biasing means for biasing the engagement member into the engaged position in the event of failure of the drive means, - wherein the engagement member includes a visual indicator visible to an operator of the 15 carrier or vehicle from an operating position of the carrier or vehicle to provide visual indication as to whether the engagement member is in the engaged position or the disengaged position. In some embodiments, the second coupling including a fixed portion that is fixed relative 20 to the quick hitch assembly and a movable portion that is pivotally movable relative to the quick hitch assembly and the engagement member is movable between an engaged position in which the engagement member engages with the movable portion of the second coupling to prevent rotatable movement of the movable portion of the second coupling relative to the quick hitch assembly and a disengaged position in which the 25 engagement member is positioned clear of the movable portion of the second coupling and the second coupling is able to rotatably move relative to the quick hitch, The attachment means may comprise opposed holes or openings formed in opposed spaced plates or ears, the opposed holes or openings arranged to receive mounting pins to 30 thereby attach the quick hitch device to a boom of a carrier or vehicle. The attachment means encompasses all known arrangements for attaching a quick hitch assembly to the boom or arnm of a carrier or vehicle.

5 The first coupling and the second coupling are used to attach the implement to the quick hitch device. The implement will typically include attachment pins that engage with the first coupling and the second coupling to thereby attach the implement to the quick hitch device. 5 The first coupling may comprise a notch or a jaw that fits over or receives an attachment pin. The notch or jaw may be formed in opposed plates or ears. Alternatively, the notch or jaw may be formed in a member. The notch or jaw may have an opening leading into sidewalls formed by opposed spaced surfaces. The attachment pin can enter into the 10 opening and move along or through the space defined by the opposed sidewalls. The notch or opening suitably has a blind end located away from the opening. The blind end defines a stop position when the attachment pin comes into contact with the blind end. The second coupling includes a fixed portion that is fixed relative to the quick hitch 15 assembly and a movable portion that is pivotally movable relative to the quick hitch assembly. The fixed portion may comprise a recessed or scalloped region. The movable portion may include a hooked region or a curved region that can move from a position that at least partially overlies the fixed portion (for example, by at least partially overlying the recessed or scalloped region) in order to maintain the implement attachment pin in the 20 fixed portion, to a position at which the hooked region or the curved region is retracted from the fixed portion to thereby allow the implement attachment pin to move away from the fixed portion. The movable portion may include a contact region that contacts the implement attachment pin when the movable portion is in a pin engaging position (being a position that at least partially overlies the fixed portion). 25 In some embodiments, the quick hitch assembly includes at least two spaced movable portions. In these embodiments, the two spaced movable portions contact the implement attachment pin at different regions along the length of the implement attachment pin to thereby securely retain the implement attachment pin. 30 The quick hitch assembly further includes an engagement member. The engagement member is moved by drive means between the engaged position and the disengaged position. In the disengaged position, the engagement member is positioned clear of the movable portion of the second coupling. Therefore, in this position, the movable portion 6 of the second coupling can move, such as pivotally move, relative to the quick hitch assembly. In one embodiment, when the engagement member moves from the disengaged position 5 to the engaged position, a first contact surface of the engagement member contacts a surface of the movable portion of the second coupling. Continued movement of the engagement member causes pivotal movement of the movable portion of the second coupling so that the movable portion moves to a position at which it at least partially overlies the fixed portion of the second coupling. The engagement member also prevents 10 rotation of the movable portion of the second coupling in a direction that would move the second portion away from the attachment pin engaging position. In one embodiment, the engagement member includes a second contact surface that contacts the movable portion when the engagement member is in the engaged position to 15 thereby prevent rotation of the movable portion away from the attachment pin engaging position. In another embodiment, the movable portion is movable between an implement attachment pin engaging position and retracted position by operation of a separate drive 20 means, such as a separate hydraulic cylinder. In this embodiment, the separate hydraulic cylinder (or other drive means) is operated to move the movable portion to the attachment pin engaging position and the drive means is subsequently operated to move the engagement member into the engaged position. When it is desired to remove the implement from the quick hitch assembly, the drive means is operated to retract the 25 engagement member to the disengaged position and a separate drive means is that operated to move the movable portion of the second coupling away from the implement attachment pin. Where the drive means and separate drive means comprise hydraulic cylinders, appropriate sequencing valves may be used to control this operation. 30 In some embodiments, the movable portion of the second coupling includes a camming member that comes into contact with the engagement member as the engagement member moves into the engaged position. The camming member may comprise, for example, a lobe.

7 In some embodiments of the present invention, the engagement member moves in a reciprocal fashion between the disengaged position and the engaged position. In some embodiments, the engagement member slides along a fixed surface of the quick hitch assembly. In other embodiments, a portion of the engagement member slides along a 5 fixed surface of the quick hitch assembly. When it is desired to release an implement from the quick hitch assembly, the drive means is operated to move the engagement member out of engagement with the movable portion of the second coupling such that the engagement member is positioned clear of the 10 movable portion of the second coupling and the second coupling can rotate away from the attachment pin engaging position. The drive means is suitably controlled by an operator from an operating position of the carrier or vehicle. Typically, the operating position of the carrier or vehicle is within a cab 15 of the carrier or vehicle. By enabling control of the drive means from the operating position of the carrier or vehicle, it is possible for the operator to attach and detach an implement from the quick hitch assembly without having to leave the operating position of the carrier or vehicle. 20 In one embodiment, the drive means comprises a hydraulic ram or cylinder, such as a two-way hydraulic ram or cylinder that can positively move the engagement member from the disengaged position to the engaged position and positively move the engagement member from the engaged position to the disengaged position. It will be appreciated that other drive means may also be used. For example, alternative drive means may include a 25 pneumatic ram, an electric motor, a stepper motor, a hydroelectric ram, a worm and gear drive, a rack and pinion drive, a scissor drive, or an electrically driven telescopic member. Other drive means by also be used. However, it will be appreciated that the carrier or vehicle typically includes hydraulic motors and hydraulic systems. Accordingly, it may be most convenient to provide the drive means in the form of a hydraulic ram or cylinder, 30 such as a two-way hydraulic ram or cylinder. Operation of the hydraulic ram or cylinder may be controlled by sequencing valves. The sequencing valves may themselves be controlled by a control system that is operable by the operator from the operating position of the carrier or vehicle.

8 In some embodiments of the present invention, the quick hitch assembly is provided with a biasing means for biasing the engagement member into the engaged position in the event of failure of the drive means. For example, if the drive means comprises a hydraulic 5 cylinder and the hydraulic system fails or a hydraulic hose ruptures, the biasing means biases the engagement member into the engaged position. If an implement is attached to the quick hitch assembly when the failure of the drive means occurs, the biasing means maintains the engagement means in the engaged position. It will be appreciated that, in this position, the movable member of the second coupling will retain and hold onto the 10 implement. Therefore, failure of the drive means will not result in disconnection of the implement from the quick hitch assembly. This can have important safety implications. The biasing means may comprise a passive biasing means. By "passive biasing means", it is meant a biasing means that does not require any external energy or power to operate. 15 Examples of such passive biasing means include springs, such as compression springs or tension springs, rubber blocks or members or elastomeric blocks or members. In one embodiment, the biasing means comprises a compression spring that is positioned between a projection extending from the engagement member and a fixed surface of the quick hitch assembly. 20 In another embodiment, the engagement member may include a visual indicator visible to an operator of the carrier or vehicle from an operating position of the carrier or vehicle. In this embodiment, the visual indicator provides a visual indication as to whether the engagement member is in the engaged position or in the disengaged position. In one 25 embodiment, the visual indicator may comprise an end of the engagement member that is visible to the operator when the engagement member is in one of the engaged position or the disengaged position, with the end of the engagement member not being visible to the operator when the engagement member is in the other of the engaged position or the disengaged position. In this manner, if the operator can see the end of the engagement 30 member, he knows that the engagement member is in one of the engagement position or the disengaged position.

9 In one embodiment, the end of the engagement member that provides the visual indicator may be visible to the operator from the operating position of the carrier or vehicle when the engagement member is in the disengaged position. 5 In some embodiments, the visual indicator may be painted a bright colour, such as a bright yellow, so that the visual indicator readily catches the eye of the operator. BRIEF DESCRIPTION OF THE DRAWINGS 10 Figure 1 comprises a side view, partly in cross section, of a quick hitch assembly in accordance with an embodiment of the present invention; Figure 2 comprises a side view, partly cross-section, of the quick hitch assembly shown in figure 1 but with further detail shown; 15 Figure 3 shows a top view of the quick hitch assembly shown in figure 1; Figure 4 shows a cross sectional side view take along section B-B of figure 3; and 20 Figure 5 is a perspective view of the quick hitch assembly shown in Figures 1 to 4. DETAILED DESCRIPTION OF THE DRAWINGS It will be appreciated that the drawings have been provided for the purposes of illustrating 25 preferred embodiments of the present invention. Therefore, it will be understood that the present invention should not be considered to be limited to the features as shown in the drawings. The quick hitch assembly 10 shown in the attached drawings comprises a chassis 12 30 formed from chassis members 14, 16 that are connected by crossmembers 18, 20. The chassis 10 carries opposed spaced plates 22, 24. Opposed spaced plates 22, 24 each include holes 26, 28. Hole 26 on plate 22 is in line with hole 26 on plate 24. Similarly, hole 28 in plate 22 is in line with hole 28 on plate 24 (as best shown in figure 3). The respective holes 26, 28 can receive an attachment pin so that the quick hitch assembly 10 10 can be attached to a boom or arm of a carrier or a vehicle. Plates 22, 24 and holes 26, 28 comprise the attachment means for attaching the quick hitch assembly 10 to the boom or arm of the carrier or vehicle. As will be known to persons skilled in the art, holes 26, 28 may be provided with bearings to enable rotational movement between the attachment 5 pins of the boom and the quick hitch assembly 10. In order to enable an implement, such as a bucket, to be attached to the quick hitch assembly 10, the quick hitch assembly 10 is also provided with a first coupling and a second coupling. The first coupling and the second coupling are designed to receive and 10 engage with attachment pins on the implement. The first coupling includes a coupling member 30. As best shown in figure 5, coupling member 30 has a significant lateral extent. The coupling member 30 is in the form of an outwardly extending ear 32 having a notch or jaw 34. The notch or jaw 34 has an opening 15 36 through which the attachment 10 of the implement can pass. Opposed side surfaces 38, 40 and blind end 42 define the remainder of the notch or jaw. In use, the opening 36 is positioned over an attachment 10 of the implement and the quick hitch assembly 10 is moved so that the attachment 10 moves into the notch until it comes into contact with the blind end 42. The coupling member 30 may comprise opposed ears 32 with infill 20 members 33 (see figure 5). In order to fully attach the implement to the quick hitch assembly 10, a second coupling 44 is provided. Second coupling 44 comprises a fixed portion 46 and a movable portion 48. Fixed portion 46 may be in the form of an extending member having a recessed region 25 50 formed therein. Recessed region 50 may include generally opposed sidewalls 52, 54 and an inner wall 56. Recessed region 50 is dimensioned so that it is slightly or somewhat bigger than an implement attachment pin. The movable portion 48 of the second coupling 44 comprises an ear 58 that is pivotally 30 mounted to the chassis of the quick hitch assembly 10 about pivot point 60. The ear 58 has a camming portion or lobe 62 and a hook portion 64. The ear 58 is also provided with an opening 66 which receives a pivot pin connected to a hydraulic cylinder 68 (see figure 2). Hydraulic cylinder 68 is pivotally mounted at its other end 70 to the chassis of the quick hitch assembly 10. The hydraulic cylinder 68 is suitably a two-way hydraulic I1 cylinder that can positively move in both a retraction direction and an extension direction. It will be seen from figure 2 that extending the hydraulic cylinder 68 will cause the movable portion 48 to pivot or rotate in a generally anti-clockwise direction so that the hook portion 64 at least partially overlies the recessed region 50 of the fixed portion 46 of 5 the second coupling 44. In this position, an implement attachment pin that is positioned in the recessed region 50 is retained in the recessed region 50 by the hook portion 64 of the movable portion 48 of the second coupling 44. In order to remove an implement from the second coupling, the hydraulic cylinder 68 is operated so that it retracts. This causes the hook portion 64 to rotate in a generally clockwise direction, which causes hook portion 64 10 to move away from overlying the recessed region 50. This effectively opens up the recessed region 50, thereby allowing the implement attachment pin to be removed out of the recessed region 50. In practice, the hook region 64 is retracted and the hydraulics controlling movement of the quick hitch assembly 10 move the recessed region 50 away from the implement attachment pin. The hydraulics or boom may then be operated to lift 15 the first coupling member 30 away from the other implement attachment pin to fully remove the implement form the quick hitch assembly. In order to provide additional safety or redundancy to ensure that the movable portion 48 of the second coupling 44 does not undesirably move away from the fixed portion 46 of 20 the second coupling 44, for example, due to hydraulic failure, the quick hitch assembly 10 is provided with an engagement member 72 in the form of a locking bar. Engagement member 72 includes a first end 74 that is arranged to slide in a reciprocal manner along a surface of chassis crossmember 18. The first end 74 of engagement member 72 includes a ramped surface 76 and an outer surface 78. The thickness of the first end 74 of 25 engagement member 72 is sufficiently large such that when the engagement member 72 is moved so that the first end 74 is positioned under the lobe 62 of the movable portion 48 of the second coupling 44, the outer surface 78 comes into contact with at least part of the lobe 62. In this manner, the engagement member 72 engages with the lobe 62 and effectively acts as a stop member to prevent any rotation of the movable portion 48 in a 30 direction that would tend to open up a gap between the movable portion 48 and the fixed portion 46 of the second coupling 44 that is sufficiently large to allow an implement pin to be removed from the second coupling.

12 As best shown in figure 1, the engagement member 72 includes a projection 80. Projection 80 is connected to a two-way hydraulic cylinder 82 to a hydraulic cylinder 82 that can be operated to positively extend and positively retract. When hydraulic cylinder 82 is extended, the engagement member 72 is moved to the right (as shown in figure 1) 5 and it adopts the position as shown in dotted outline 84 in figure 1. In this position, the engagement member 72 is positioned so that it lies between the lobe 62 and the chassis crossmember 18, thereby largely preventing rotation of the movable portion 48 in a generally clockwise direction. 10 When the hydraulic cylinder 82 is actuated so that it retracts, the engagement member 72 moves to the left (as shown in figure 1). This causes the end 74 to move out from between the lobe 62 and the chassis crossmember 18. In this position, the engagement member 72 does not prevent rotation of the movable portion 48 in a generally clockwise direction (as shown in figure 1). Therefore, in this position, it is possible to open the movable portion 15 48 of the second coupling 44. As a further safety feature or redundancy built into the quick hitch assembly 10 shown the attached drawings, the engagement member 72 is also provided with a second projection 86. A compression spring 88 is positioned between the second projection 86 of 20 engagement member 72 and an inner wall 90 of the coupling member 30. As will be known to person skilled in the art, both the projection 86 and inner wall 90 may be provided with knobs to seat respective ends of the spring 88. Spring 88 biases the engagement member 72 to the engaged position as shown in dotted outline 84 in figure 1. Therefore, should the hydraulics fail such that hydraulic cylinder 82 no longer functions 25 properly, the spring 88 will bias the engagement member 72 to the engaged position as shown by dotted outline 84. This adds a further level of safety and redundancy to the quick hitch assembly 10. As a further safety feature included on the quick hitch assembly 10 shown in the attached 30 drawings, the second end 90 of the engagement member 72 extends through a slot 92 in chassis crossmember 94. When the engagement member 72 is in the disengaged position (as shown in solid outline in figure 1), the end 90 is visible to the operator. In this regard, it will be appreciated that the operator is looking at the quick hitch assembly 10 from the direction shown by arrow 96 in figure 1. Therefore, the end 90 of the engagement member 13 72 can be seen extending through the slot 92 when the engagement member is in the disengaged position. Suitably, the end 90 is painted a high visibility colour, such as bright yellow, so that it catches the eye of the operator. If the operator notices the end 90 being visible when an implement is attached to the quick hitch assembly 10, the operator will 5 readily see that the engagement member 72 is not in the engaged position. The operator will then be prompted by the visual indicator to take corrective action. In order to connect an implement to the quick hitch assembly 10, the cylinder 68 is retracted. The arm or boom is then moved so that the opening 36 of the first coupling 10 member 30 is positioned over an attachment pin of the implement and the quick hitch assembly 10 is then raised so that the implement attachment pin moves into contact with the blind end 42 (typically, the first coupling 30 is used to couple to the upper of the attachment pins on the implement). The hydraulic controls are then actuated so that the second implement coupling pin is positioned in the recessed region 50. Cylinder 68 is 15 operated to extend and to cause the movable portion 48 of the second coupling 44 to close over the other of the implement attachment pins. The cylinder 82 is then operated to extend, thereby causing the engagement member 72 to move between the crossmember 18 and the lobe 62 of the movable portion 48 of the second coupling 44. In this position, the movable portion 48 can not move away from the implement attachment pin due to the 20 presence of the end 74 of the engagement member 72 underneath the lobe 62. At the same time, the second end 90 of the engagement member 72 (which end comprises a visual indicator) has moved inwardly so that it is no longer visible to the operator of the carrier or vehicle. This provides a visual indicator to the operator that the engagement member is properly in the engaged position. Spring 88 assists in maintaining the engagement 25 member 72 in the engaged position. Removing the implement from the quick hitch assembly 10 involves the opposite procedure. In particular, cylinder 82 is retracted to thereby retract engagement member 72. The cylinder 82 retracts the engagement member against the force of the biasing 30 spring 88. Cylinder 68 is then retracted to cause the movable portion 48 to rotate away from the implement attachment pin. Tthe hydraulics are then operated to move the quick hitch attachment 10 away from that implement attachment pin, followed by moving of the quick hitch assembly 10 away from the other of the implement attachment pins positioned in the first coupling 30.

14 In some embodiments, the engagement member 72 is held in place by a block. Should hydraulic pressure fail in the field, it is possible to move the engagement member out of the way by undoing the block that holds the engagement member in place (for example, 5 bu undoing bolts that hold the block in place) and then manoeuvering the engagement member out of the way. This will provide a simple and effective in-field fix in the event of hydraulic failure. The present invention provides a quick hitch assembly with improved safety. In preferred 10 embodiments of the present invention, the following safety features/redundancies are built in to ensure that an implement remains safely attached to the quick hitch assembly even in the event of hydraulic failure: 1) positioning of the engagement member underneath the movable portion of the second 15 coupling to prevent rotation of the movable portion in a direction that would allow the implement attachment pin to be separated from the second coupling; 2) biasing means, such as a spring, biasing the engagement member to the engaged position to maintain the engagement member in the engaged position in the event of 20 hydraulic failure; and 3) the engagement member providing a visual indicator to an operator of the quick hitch assembly to provide a visual warning that the engagement member is not properly engaged. 25 Thus, preferred embodiments of the present invention provide for three separate safety features, as described above. Those skilled in the art will appreciate that the present invention may be susceptible to 30 variations and modifications other than those specifically described. It will be understood that the present invention encompasses all such variations and modifications that fall within its spirit and scope.

Claims (20)

1. A quick hitch assembly for attaching an implement to a boom of a carrier or vehicle, the quick hitch assembly comprising 5 - attachment means for attaching the quick hitch assembly to a boom of a carrier or a vehicle, - a first coupling for receiving an implement mounting pin, - a second coupling for receiving an implement mounting pin, the second coupling including a fixed portion that is fixed relative to the quick hitch assembly and a movable 10 portion that is movable relative to the quick hitch assembly, - an engagement member movable between an engaged position in which the engagement member engages with the movable portion of the second coupling to prevent movement of the movable portion of the second coupling relative to the quick hitch assembly and a disengaged position in which the engagement member is positioned clear of the movable 15 portion of the second coupling and the second coupling is able to move relative to the quick hitch, and - drive means for selectively driving the engagement member between the engaged position and the disengaged position, - wherein the engagement member includes a visual indicator visible to an operator of the 20 carrier or vehicle from an operating position of the carrier or vehicle to provide visual indication as to whether the engagement member is in the engaged position or the disengaged position.

2. A quick hitch assembly for attaching an implement to a boom of a carrier or 25 vehicle, the quick hitch assembly comprising - attachment means for attaching the quick hitch assembly to a boom of a carrier or a vehicle, - a first coupling for receiving an implement mounting pin, - a second coupling for receiving an implement mounting pin, the second coupling 30 including a fixed portion that is fixed relative to the quick hitch assembly and a movable portion that is movable relative to the quick hitch assembly, - an engagement member movable between an engaged position in which the engagement member engages with the movable portion of the second coupling to prevent movement of the movable portion of the second coupling relative to the quick hitch assembly and a 16 disengaged position in which the engagement member is positioned clear of the movable portion of the second coupling and the second coupling is able to move relative to the quick hitch, - drive means for selectively driving the engagement member between the engaged 5 position and the disengaged position, and -biasing means for biasing the engagement member into the engaged position in the event of failure of the drive means.

3. A quick hitch assembly for attaching an implement to a boom of a carrier or 10 vehicle, the quick hitch assembly comprising - attachment means for attaching the quick hitch assembly to a boom of a carrier or a vehicle, - a first coupling for receiving an implement mounting pin, - a second coupling for receiving an implement mounting pin, the second coupling 15 including a fixed portion that is fixed relative to the quick hitch assembly and a movable portion that is movable relative to the quick hitch assembly, - an engagement member movable between an engaged position in which the engagement member engages with the movable portion of the second coupling to prevent movement of the movable portion of the second coupling relative to the quick hitch assembly and a 20 disengaged position in which the engagement member is positioned clear of the movable portion of the second coupling and the second coupling is able to move relative to the quick hitch, - drive means for selectively driving the engagement member between the engaged position and the disengaged position, 25 - biasing means for biasing the engagement member into the engaged position in the event of failure of the drive means, - wherein the engagement member includes a visual indicator visible to an operator of the carrier or vehicle from an operating position of the carrier or vehicle to provide visual indication as to whether the engagement member is in the engaged position or the 30 disengaged position.

4. A quick hitch assembly as claimed in any one of the preceding claims wherein the second coupling including a fixed portion that is fixed relative to the quick hitch assembly and a movable portion that is pivotally movable relative to the quick hitch assembly and 17 the engagement member is movable between an engaged position in which the engagement member engages with the movable portion of the second coupling to prevent rotatable movement of the movable portion of the second coupling relative to the quick hitch assembly and a disengaged position in which the engagement member is positioned 5 clear of the movable portion of the second coupling and the second coupling is able to rotatably move relative to the quick hitch,

5. A quick hitch assembly as claimed in any one of the preceding claims wherein the attachment means comprises opposed holes or openings formed in opposed spaced plates 10 or ears, the opposed holes or openings arranged to receive mounting pins to thereby attach the quick hitch device to a boom of a carrier or vehicle.

6. A quick hitch assembly as claimed in any one of the preceding claims wherein the first coupling and the second coupling are used to attach the implement to the quick hitch 15 assembly and the implement includes attachment pins that engage with the first coupling and the second coupling to thereby attach the implement to the quick hitch device.

7. A quick hitch assembly as claimed in any one of the preceding claims wherein the first coupling comprises a notch or a jaw that fits over or receives an attachment pin, the 20 notch or jaw being formed in opposed plates or ears, or the notch or jaw being formed in a member, the notch or jaw having an opening leading into sidewalls formed by opposed spaced surfaces wherein an attachment pin enters into the opening and moves along or through the space defined by the opposed sidewalls, the notch or opening having a blind end located away from the opening, the blind end defineing a stop position when the 25 attachment pin comes into contact with the blind end.

8. A quick hitch assembly as claimed in any one of the preceding claims wherein the fixed portion comprises a recessed or scalloped region, the movable portion includes a hooked region or a curved region that can move from a position that at least partially 30 overlies the fixed portion by at least partially overlying the recessed or scalloped region in order to maintain the implement attachment pin in the fixed portion, to a position at which the hooked region or the curved region is retracted from the fixed portion to thereby allow the implement attachment pin to move away from the fixed portion. 18

9. A quick hitch assembly as claimed in claim 8 wherein the movable portion includes a contact region that contacts the implement attachment pin when the movable portion is in a pin engaging position, being a position that at least partially overlies the fixed portion. 5

10. A quick hitch assembly as claimed in any one of the preceding claims wherein the quick hitch assembly includes at least two spaced movable portions, the two spaced movable portions contacting an implement attachment pin at different regions along the length of the implement attachment pin to thereby securely retain the implement 10 attachment pin.

11. A quick hitch assembly as claimed in any one of the preceding claims wherein, when the engagement member moves from the disengaged position to the engaged position, a first contact surface of the engagement member contacts a surface of the 15 movable portion of the second coupling and continued movement of the engagement member causes pivotal movement of the movable portion of the second coupling so that the movable portion moves to a position at which it at least partially overlies the fixed portion of the second coupling. 20

12. A quick hitch assembly as claimed in claim 11 wherein the engagement member also prevents rotation of the movable portion of the second coupling in a direction that would move the second portion away from the attachment pin engaging position.

13. A quick hitch assembly as claimed in any one of the preceding claims wherein the 25 engagement member includes a second contact surface that contacts the movable portion when the engagement member is in the engaged position to thereby prevent rotation of the movable portion away from the attachment pin engaging position.

14. A quick hitch assembly as claimed in any one of the preceding claims wherein the 30 movable portion is movable between an implement attachment pin engaging position and retracted position by operation of a separate drive means.

15. A quick hitch assembly as claimed in any one of the preceding claims wherein the movable portion of the second coupling includes a camming member that comes into 19 contact with the engagement member as the engagement member moves into the engaged position.

16. A quick hitch assembly as claimed in any one of the preceding claims wherein the 5 engagement member moves in a reciprocal fashion between the disengaged position and the engaged position.

17. A quick hitch assembly as claimed in any one of the preceding claims wherein the drive means is controlled by an operator from an operating position of the carrier or 10 vehicle such that it is possible for the operator to attach and detach an implement from the quick hitch assembly without having to leave the operating position of the carrier or vehicle.

18. A quick hitch assembly as claimed in any one of the preceding claims wherein, 15 the drive means comprises a hydraulic ram or cylinder, or a two-way hydraulic ram or cylinder that can positively move the engagement member from the disengaged position to the engaged position and positively move the engagement member from the engaged position to the disengaged position, or a pneumatic ram, an electric motor, a stepper motor, a hydroelectric ram, a worm and gear drive, a rack and pinion drive, a scissor 20 drive, or an electrically driven telescopic member.

19. A quick hitch assembly as claimed in any one of the preceding claims wherein the quick hitch assembly is provided with a biasing means for biasing the engagement member into the engaged position in the event of failure of the drive means. 25

20. A quick hitch assembly as claimed in any one of the preceding claims wherein the engagement member includes a visual indicator visible to an operator of the carrier or vehicle from an operating position of the carrier or vehicle, said visual indicator providing a visual indication as to whether the engagement member is in the engaged position or in 30 the disengaged position.