AU2013204053B2 - A Towing Coupling - Google Patents

Abstract

A coupling for coupling a towed vehicle to a towing vehicle is described. One embodiment of the coupling is a self-actuating coupling which includes: a towball receiver body including a receiver void disposed within the towball receiver body, the receiver void including one or more internal walls for cooperating with a towball; a locking element disposed within the towball receiver body, the locking element movable between a stowed position in which the locking element allows the towball to move freely in and out of the receiver void, and a deployed position in which the locking element extends into the receiver void to inhibit movement of the towball out of the void; and a lock actuation assembly operatively connected with the locking element and including a lock self actuator comprising a distal end, the lock self-actuator being movable between a standby position and an actuation position, wherein the lock actuation assembly includes a biasing means operatively connected to the lock self-actuator to bias the distal end into the receiver void so that when a towball is received into the receiver void the lock self-actuator is driven by the towball against the bias to an actuation position to move the locking element between the stowed position and the deployed position. '2 2 ~N"' N N K. 4" 4' N ~' ~ .~'' ~ \ 2 "&' " 'N" ' $ "~2 N*NN ~"NN >2 ' ' NNN~ \ At 'N N' 'N 'N 2 '2"" ~ " ' "N' N "N' >2 ~ *' "" 'N""' >2 '~' N ~ '~ ""N' & "~ ~> ~tA ">' ' ' N "# \~ "N "Nh N~ ~'\ N NNN\ N~ N\N\ N NN N\ N\\ *'.~ N \~ \~ ~ "N ~' \~ N "N >N 2 ~""'N""N'N"""" ~ Nx \~ N\ \\ '>2. ~ N N2 N \ N N N \ NN >2' 4 ~ N~ NN N N \ NN NN ~'N N\N "N NN NN "NN NN "N \ N N\ \ N~ NN '~N >N NN \ N \ N\ NN N N NN N "' \NNNNNNNNNNNN2"NNNN N N \ N N'2 ~' \ \ N\ N' ~ ""'N\ 2\ N N~,* '%'~ N A N N\ NN N\ NNoNN~~ 'N NN N NN ~N\N ~ """N \ N\ \ \ \~'' N >2 \ N\ N N~ N~' 'N N ~ ' N 2 ~ N~ NN N N N22 ' 'N "N NN "N 2 N NN NN N ~ \ " 2' "2 <~ N N NN ~' ~' ' ~~""""k' N N \'N \ NN N N N '\""'"" V a N~ NN N~ ' ~ N~ NN NN 2~NN\ A \ N~\ '>2" 2 ~NN N~ "N NN ~~>2' 'N *\ "N N' NN N~'N~ *>2 ' >2 NN NN N "N N\ \ ~ \4N.>< N \N N \ ~>~\ \ NN N~ 4 N NN \ N 2 "N "N "N 'N> ~ N~ NN >2 >2'N2N~ 2NN 2 NN "N NN 2 '\'>2""'* >22 ~ NNN ' 2 "N " N "~ 2 \N\'~N&N\N"NNNN\\'~NNNN\ ~'.2 '~ N~ NN N \~ NN "N "N' N NN " \N~ N~ >2 K "N "N 'NN "N NN " '. N 'N '~ N~ V~ N N N\ N~ '~ ~' '~ ""N NN NN K "N "'N "'N>2 '> NN "'N " " " ~\ NN NN ~ "N N\ NN ~ ~ \NN'>N~ 'N"

Description

A TOWING COUPLING

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Field of the invention [001] The present invention relates generally to a towing coupling for coupling a towed vehicle and a towing vehicle via a towball mounted on the towing vehicle. Particular embodiments of the present invention find effective application in towing couplings for offroad vehicles.

Background of the invention [002] Towing couplings are used to couple towing vehicles and towed vehicles, such that the towing and towed vehicles are securely kept together while negotiating undulating, twisting and/or corrugated road or track.

[003] Typical, on-road towing couplings include a ball receiver housing and a tongue, the arrangement for cooperating with a towball mounted on a hitch at the back of the towing vehicle. The tongue can move between a standby position and a coupled position. In the standby position, the tongue generally hangs loosely down and away from the ball receiver housing.

[004] To adopt the coupled position, suitable for when the towball is disposed within the ball receiver housing, the tongue is drawn upwards toward a cheek of the ball. The tongue can be drawn upwards towards the cheek of the ball by various methods, including a screw mechanism, a lever or cam surface. Known couplings are generally secure, however, they are expensive, complex, difficult to manufacture, cumbersome, time consuming and difficult to couple and release.

[005] Furthermore, off-road couplings, which are known to require greater angular freedom and security than that which may be provided by known towball couplings, are generally in the form of a multi-axis connector block connected to a towing vehicle. The multi-axis connector block includes at least two through bores, each through bore disposed alongside one another and disposed along orthogonal axes. To install, the connector block is received in a towing hitch, a pivot pin is passed through the towing hitch and into one bore to provide the block with a pivoting coupling to the towing vehicle with freedom to rotate about one axis relative to the towing vehicle. The other one or more bores allow pivoting about one or more axes orthogonal to the coupling pin.

[006] As can be seen, rather than using the towball mounted on the hitch, the off-road j coupling requires a separate pin and multi-axial connector block connection to a hitch which requires a separate investment to enable off-road use.

[007] The present invention seeks to ameliorate one or more of the abovementioned disadvantages and/or provides a new coupling.

Summary of the invention [008] In one broad aspect the present invention provides a coupling adapted to mount to a towed vehicle for coupling the towed vehicle to a towball mounted on a towing vehicle, the coupling when coupled to the towball limiting angular rotation of the coupling about the towball to angular rotation about a longitudinal axis of the towball.

[009] In another broad aspect the present invention provides a self-actuating coupling adapted to mount to a towed vehicle for self-actuation of a towball receiver lock assembly onto a towball of a towing vehicle by the action of the towball extending into a towball receiver.

[010] In yet another broad aspect the present invention provides a towing coupling having a manually-operated locking element, the locking element rotatable between a stowed position and a deployed position. Preferably the locking element rotates about a roll axis to move between the stowed and deployed positions.

[011] According to a first aspect of the present invention there is provided a coupling for coupling a towed vehicle to a towing vehicle, the coupling including: a towball receiver body including a towball receiver void disposed within the towball receiver body, the towball receiver void including a contoured internal wall for cooperating with a towball; a locking element including a contoured trapping surface and movable between a stowed position and a deployed position such that when the locking element is disposed in the stowed position, the trapping surface conforms to the contoured internal wall of the towball receiver void so as to form a portion of the contoured internal wall, and when the locking element is disposed in the deployed position, at least a portion of the contoured trapping surface is spaced from the contoured internal wall and extending into the towball receiver void a selected distance so as to substantially abut a cheek of the towball to inhibit release of the towball from the towball receiver void; a handle which is operatively connected to the locking element to move the locking element between the stowed position and the deployed position; and a keeper operatively connected to the handle , such that it is configured to j selectively interengage therewith to selectively keep the lock element in the stowed and the deployed positions. In one embodiment the handle includes a biasing element to move the locking element between the stowed position to the deployed position.

[012] Most known towballs include a generally elongate main body which includes a spherical ball at one end with a flat top, the ball mounted on a neck having a waisted midsection, a cylindrical flange disposed at and extending laterally from the base of the neck, and an elongate threaded shaft at the base of the cylindrical flange.

[013] Preferably the locking element is in the form of a trap which includes a trapping surface, the arrangement of the trap being such that when the locking element is disposed in the stowed position, the trapping surface is disposed substantially flush with the one or more cooperating internal walls of the towball receiver, the arrangement being preferably that the trapping surface also cooperates with the towball. The arrangement also preferably is such that when the locking element is disposed in the deployed position, the trapping surface is spaced from the cooperating internal walls of the towball receiver and into the void so as to abut a cheek of a towball in the towball receiver to inhibit release of the towball through the opening of the towball receiver.

[014] Preferably one of the one or more internal walls of the receiver void is in the form of a ceiling.

[015] Preferably the distal end of the lock self-actuator extends into the receiver void from the ceiling in an arrangement such that the towball is substantially within the towball receiver void before the lock is self-actuated. Preferably the lock self-actuator extends through the ceiling of the towball receiver body. Preferably the proximal end of the lock self-actuator extends beyond a top surface of the towball receiver body.

[016] Preferably the internal walls include a generally spherical wall portion for cooperating with a ball portion of the main body of the towball and a collar for cooperating with a flange of the main body of the towball, the collar disposed below the generally spherical wall portion, the arrangement being such that when the coupling is coupled to the main body of the towball, the generally spherical wall portion and collar cooperate with the main body of the towball so that angular rotation of the coupling about the towball is limited to angular rotation about a yaw axis, or in other words a longitudinal axis of the main body of the towball.

[017] Preferably the trapping surface is contoured so as to be generally similar in contour to the one or more cooperating internal walls when the trap is in the stowed position.

[018] Preferably the actuation assembly includes a keeper operatively associated with the lock self-actuator. Preferably the lock self-actuator in use moves the keeper between a keeping position in which the keeper keeps the locking element in the stowed position and a release position in which the keeper releases the locking element from the stowed position. Preferably the keeper is biased to the keeping position by a keeper biasing means. Preferably the keeper biasing means is a spring.

[019] Preferably the locking element is operatively connected to a handle so that movement of the handle causes movement of the locking element. Preferably the handle and the locking element are mounted to a common shaft which rotates to move the locking element between the stowed and deployed positions.

[020] Preferably the keeper is also operatively associated with the handle so that in use the keeper keeps the handle in stowed and deployed positions, which correspond with the stowed and deployed positions of the lock assembly.

[021] Preferably the keeper is in the form of an arm which moves between the keeping position and the release position. Preferably the keeper is pivotally mounted to the towball receiver to move between the keeping and release positions. Preferably the keeper is connected to an outside surface of the towball receiver body. Preferably the keeper is connected to an upper surface of the towball receiver body so that the proximal end of the lock self-actuator can move the arm between the keeping position and the release position.

[022] Preferably the trap is in the form of a tongue disposed on a side wall of the receiver void. Preferably the tongue is rotatably mounted so as to rotate about a horizontal axis so as to move between the stowed and deployed positions. Preferably the tongue is affixed to the handle so that the handle rotates with the tongue. Preferably the horizontal axis extends generally through the centre of the void so that, when the trap moves from the stowed to the deployed position, a portion of the tongue which formed the cooperating internal side wall abuts the cheek of the towball.

[023] Preferably the handle is in the form of a rotor including a radial tab extending therefrom. Preferably, also extending from the rotor are two spaced-apart radial shoulders at either ends of a cam. A first one of the radial shoulders of the cam is shorter than the second one of the radial shoulders of the cam.

[024] Preferably the handle includes a rotor biasing element to bias the handle towards the deployed position. Preferably the rotor biasing element is in the form of a rotor torsion spring.

[025] When the locking element and rotor are disposed in the stowed position, the first one of the cam shoulders on the rotor is kept by the rotor biasing means against the pivoting flap of the keeper so that the tongue is kept in the stowed position. This stowed position is maintained until a towball is inserted into the towball receiver and hits the distal end of the lock self-actuator, moving it to the actuation position.

[026] When the locking element and rotor are disposed in the deployed position, the second one of the cam shoulders is kept by the keeper biasing means against the keeper.

[027] The tab is provided for gripping by an operator's hand when resetting the selfactuation of the rotor; that is, to move the rotor from the deployed position, against the rotor spring torsion, back to the stowed position.

[028] Preferably the keeper is further articulated in that it includes a pivoting keeping flap. The pivoting keeping flap in preferred embodiments is adapted to extend below the keeper arm so as to reach the shoulder to hold the rotor and tongue in the unlocked or stowed position to facilitate the unlocking operation. That is, the pivoting flap holds the handle in an unlocked position while the towball is in the housing and holds the actuator high and the pivoting arm in an elevated position.

[029] According to a second aspect of the present invention there is provided a coupling for coupling a towed vehicle to a towing vehicle, the coupling including: a towball receiver body including a receiver void including one or more internal walls for cooperating with a towball, the one or more internal walls; a locking element disposed within the towball receiver and movable between a stowed position and a deployed position, wherein the locking element includes a trap including a trapping surface, such that when the locking element is disposed in the stowed position, the trapping surface is disposed substantially flush with the one or more cooperating internal walls of the towball receiver void, and such that when the locking element is disposed in the deployed position, the trapping surface is spaced from the cooperating internal walls of the towball receiver and into the receiver void so as to substantially abut a cheek of a towball in the towball receiver to inhibit release of the towball from the towball receiver void.

[030] Preferably the trap is manually actuated and rotates to move between the stowed and deployed positions. Preferably the trap rotates about the roll axis to move between the stowed and deployed positions.

[031] According to a third aspect of the present invention there is provided a coupling adapted to mount to a towed vehicle for coupling the towed vehicle to a main body of a towball mounted on a towing hitch of a towing vehicle, the coupling including: a towball receiver body including a receiver void disposed within the towball receiver body, the receiver void including one or more internal walls for cooperating with the main body of a towball, the internal walls including a spherical wall portion for cooperating with a ball portion of the main body of the towball and a collar for cooperating with a flange of the main body of the towball, the collar disposed below the spherical wall portion; the arrangement being such that when the coupling is coupled to the main body of the towball, the spherical wall and collar cooperate with the main body of the towball so that angular rotation of the coupling about the towball is limited to angular rotation about a longitudinal axis of the main body of the towball.

[032] Generally, the pivoting axis of the main body of the towball is vertical.

[033] Preferably a yoke is provided to mount the coupling to the towed vehicle. The yoke includes parallel arms and a connecting base to connect the parallel arms together. Preferably the parallel arms include pivoting ends to connect to the coupling. Preferably the pivoting arms provide a pivoting axis which is transverse to the vehicle, so that the coupling can pitch about that axis.

[034] Preferably there is provided a step on the yoke so that the coupling is inhibited from pitching rearwardly, so as to facilitate single-handed operation.

[035] Preferably the connecting base includes a yaw pivot so that the yoke and coupling can pivot about that yaw axis.

Brief Description of the drawings [036] In order to enable a clearer understanding, the invention will now be further explained and illustrated by reference to the accompanying drawings, in which: [037] Figure 1 is an isometric view of a self-actuating coupling for coupling to a towball of a towing vehicle, the self-actuating coupling shown being in accordance with a preferred embodiment of the present invention, the self-actuating coupling being shown in Figure 1 in a coupled position, installed in a yoke of a drawbar of a towed vehicle; [038] Figure 2 is a plan view of the yoke and coupling shown in Figure 1; [039] Figure 3 is a side elevation view of the yoke and coupling shown in Figure 1; [040] Figure 4 is an isometric view of the coupling of Figure 1 shown without yoke for clarity; [041] Figure 5 is a port (or left) side elevation view, sectioned through a midsection, of the coupling of Figure 1;

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[042] Figure 6 is a plan view of the coupling of Figure 1 without yoke; [043] Figure 7 is a rear elevation view of the coupling of Figure 1 shown coupled to a towball, wherein a locking element is in a deployed position; [044] Figure 8 is a right (or starboard) side elevation view of the coupling of Figure 1 shown coupled to a towball, a locking element being in a deployed position; [045] Figure 9 is a front elevation view of the coupling shown in Figure 1 shown coupled to a towball, a locking element being in a deployed position; [046] Figure 10 is a port side elevation view, section about a midsection, of the coupling shown in Figure 1 shown coupled to a towball, a locking element being in a deployed position, the sectioned view showing the locking element in a deployed position underneath the towball; [047] Figure 11 is a plan view of the coupling shown in Figure 1, the coupling shown in a coupled position on a towball (not shown); [048] Figure 12 is a rear elevation view of the coupling shown in Figure 1, the coupling shown in an uncoupled position; [049] Figure 13 is a starboard side elevation view of the coupling shown in Figure 1, the coupling being disposed in an unlocked position and connected to a towball, a moment before the lock is self-actuated by the presence of the towball; [050] Figure 14 is a port elevation view, sectioned along a midportion, of the coupling of Figure 1 connected to a towball, in the unlocked position, a moment before release into the locked position; and [051] Figure 15 is a side elevation view, sectioned along a midportion, of the coupling of Figure 1, with a towball shown being inserted into a bore of the coupling, the coupling being in an unlocked position ready to receive and trap the towball.

Detailed Description of a Preferred Embodiment [052] Referring to the drawings there is shown a coupling generally indicated at 10. The embodiment of the coupling 10 shown is a self-actuating coupling 11 being in use mounted on a towed vehicle (not shown), the self-actuating coupling being suitable for coupling the towed vehicle and a towing vehicle (not shown) together.

[053] The self-actuating coupling 11 includes a towball receiver body 12 which includes a housing 14 which includes one or more internal walls 16, the one or more internal walls " 16 being a hollow substantially spherical upper portion 17 and a collar 19. An opening 18 to a receiver void 20 is disposed at the base of the collar 19. The one or more internal walls 16 are for cooperating with and abutting a substantially spherical towball 22 when it is inserted through the opening 18 into the void 20 of the towball receiver body 12.

[054] A locking element 26 is disposed within the towball receiver body 12 and is connected to a lock handle 28 and a lock actuation assembly 30. The locking element 26 is in the form of a trap 32 which itself includes a trapping surface 34, the trap 32 being adapted to move between a stowed position (Figure 5) in which the trapping surface 34 is disposed substantially flush with the one or more internal walls 16 so that it forms a portion of the one or more internal walls, and a deployed position (Figure 10) in which the trapping surface 34 is spaced from the internal walls 16 and into the receiver void 20 to substantially abut a cheek 36 of the towball 22 to inhibit release of the towball 22 from the towball receiver body 12.

[055] The actuation assembly 30 includes a keeper 38 and a lock self-actuator 40, the lock self-actuator 40 including a distal end 42, the lock self-actuator 40 being adapted to move between a standby position (Figure 5), in which the distal end 42 of the lock selfactuator 40 is disposed spaced from a ceiling 41 for actuation by the insertion of the towball 22 into the void 20, and an actuation position (Figure 10) in which the distal end 42 of the lock self-actuator 40 is disposed substantially flush with the ceiling 41 of the towball receiver body 12. In use, this arrangement is so that the lock self-actuator 40 may move the keeper 38 to a release position (Figure 10) to release the handle 28 to facilitate the movement of the locking element 26 into the deployed position (Figure 10).

[056] The keeper 38 is a pivoting arm which pivots about pivot shaft 58. The keeper 38 is also biased to a keeping position by a biasing means in the form of a spring 59.

[057] The keeper 38 is further articulated in that there is a pivoting flap 60 provided. The pivoting flap 60 is adapted to extend below the pivoting keeper 38 so as to reach a first shoulder 50 to hold the rotor 46 and locking element 26 in the stowed position.

[058] The trapping surface 34 is contoured so as to be generally similar in contour to the one or more cooperating internal walls 16 when the trap 32 is in the stowed position.

[059] The trap 32 is in the form of a tongue 33 disposed on a side 21 of the void 20. The tongue 33 is rotatably mounted so as to rotate about a horizontal axis 44. The tongue 33 is affixed to the handle 28 so that the handle 28 rotates with the tongue 33 on a common shaft rotating on the common horizontal axis 44. The horizontal axis 44 extends generally through the centre of the void 20 so that, when the trap 32 moves from the stowed position to the deployed position, an abutting portion 37 of the tongue 33 which formed a portion of the cooperating internal wall 16 spins to abut the cheek 36 of the towball 22.

[060] The handle 28 is in the form of a rotor 46, the rotor 46 including a tab 48 extending therefrom. There is also a cam 69 disposed on a periphery of the rotor 46, the cam 69 having a first shoulder 50 and a second shoulder 55 thereon. The handle 28 includes a rotor biasing means 52 to bias the handle 28 towards a deployed position which corresponds to the lock deployed position. The biasing element 52 is in the form of a rotor torsion spring 54. The pivoting keeper 38 is further articulated in that there is a pivoting flap 60 provided. The pivoting flap 60 is adapted to extend below the pivoting keeper 38 so as to reach the shoulder 50 to hold the rotor 46 and tongue 33 in the stowed position.

[061] When the locking element 26 and rotor 46 are disposed in the stowed position, the first one of the cam 69 shoulders 50 on the rotor 46 is kept by the rotor biasing means 52 against the pivoting flap 60 of the keeper so that the tongue is kept in the stowed position. Also facilitating keeping the keeper 38 and pivoting flap 60 in a keeping position against the first cam 69 shoulder 50 is the keeping spring 59. This stowed position is maintained by the springs 54 and 59 until a towball is inserted into the towball receiver body 12 and hits the distal end of the lock self-actuator 40, moving against the biasing force of the spring 59 to lift the lock self-actuator 40 to the actuation position in which the keeper is pivoted clear of the first shoulder 50.

[062] When the locking element 26 and rotor 46 are disposed in the deployed position, the second one of the cam 69 shoulders 55 is kept by the keeper biasing means 59 against the keeper 38.

[063] The tab 48 is provided for gripping by an operator's hand when resetting the selfactuation of the rotor 46; that is, to move the rotor 46 from the deployed position, against the rotor spring torsion 54, back to the stowed position.

[064] The collar 19 is adapted to be a good fit with the base flange of the towball 22 as shown in Figure 14 and the towball receiver body 12 will be inhibited from rotation about all axes except for the yaw axis or longitudinal axis 99 of the main body of the towball.

That is, the towball receiver body 12 is limited to yawing motion when mounted on the towball 22.

[065] The towball receiver body 12 is mounted in a yoke 95. The yoke 95 includes spaced apart parallel arms 96, 97 and a connecting base 98 to space the parallel arms apart and connect them together. The parallel arms 96 and 97 include bearings at their ends to pivotally connect the towball receiver body, facilitating the towed vehicle to pitch in response to bumps or other terrain.

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[066] There is provided a step 94 on at least one of the parallel arms of the yoke 95 so that the towball receiver body 12 is inhibited from pitching rearwardly too far (say 30°) so as to facilitate single-handed coupling operation described below.

[067] Preferably the connecting base 98 includes a roll bearing 93 so that the towed vehicle (not shown) can roll about the roll axis 7.

[068] In a coupling or deploying operation, the self-actuating coupling 10 is set so that the trap 32 is disposed in the stowed (or unlocked) position shown in Figure 5. An operator holds the connecting base (not shown, but positioned at the rear of the yoke 95) of the towed vehicle with one or both hands and brings it close to the towball 22 of the towing vehicle and inserts the towball 22 into the opening 18 and the void 20 until the top of the towball 22 makes contact with the distal end 42 of the lock self-actuator 40.

[069] The operator continues to insert the towball 22 into the void against the biasing force of the keeper spring 59 which normally keeps the lock self-actuator 40 extending into the void 20, and the pivoting keeper 38 will lift under the influence of the rising actuator 40.

[070] The towball 22 then seats against the one or more internal walls 16 and the pivoting flap 60 is lifted high, clear of the shoulder 50 and the pivoting keeper 38 clears the cam 69. The rotor spring 54 then drives the rotation of the handle 28, tab 48, cam 69 and trap 32 about the horizontal axis 44 from the stowed (unlocked) position to the deployed position. The abutting portion 37 of the trapping surface 34 which once formed one of the cooperating internal walls 16 has now spun and is now abutting the cheek 36 of the towball 22.

[071] To unlock the coupling, or stow the trap 32, the operator lifts the pivoting keeper 38 so that the keeper 38 clears the higher (second) shoulder 55 of the cam 69 and then grips the handle 28 and tab 48, and rotates it about the horizontal axis 44. The operator then pushes flap 60 downwards into a depressed position, or it is allowed to fall into the depressed position, and the operators rotates the tab 48 and until the first shoulder 50 of the cam 69 passes the pivoting keeper 38 and flap 60. The operator then allows the rotor 46 to rotate back under the influence of the rotor spring 54 and allows the keeper 38 to be driven down by the keeper spring 59 until the shoulder 50 abuts the flap 60. The flap 60 thus holds the handle 28 in the unlocked position and the springs of the keeper and the rotor keep the friction between the shoulder 50 and the flap 60 high enough to inhibit disengagement.

[072] The flap 60 therefore can facilitate unlocking by holding the handle 28 in the unlocked position while the towball is still fully in the housing and holding the pivoting keeper 38 upwards, which would normally be a release position in which the handle would be released to allow the handle 28 to rotate to the locked position. This frees both the user's hands to concentrate on removing the towball from the towball housing. During the unlocking operation the trap 32 will be moved from its deployed position where it blocks the exit of the towball 22, and moved to the stowed or unlocked position wherein the trapping surface 34 and abutment surface 37 adopt positions as part of the one or more cooperating internal walls 16. The towball 22 will be able to exit the void 20 via the opening 18, and the actuator 40 will drop back into the void 20.

[073] Advantageously the coupling of preferred embodiments of the present invention inhibits rotation of the towball receiver body 12 to a yaw axis 99 because of the collar 19 locating on the flange 23 of the towball 22. In the deployed position the trap 32 is extended to be disposed under a cheek 36 of the ball 22 of the main body of the towball and the collar improves the holding force of the trap by limiting the movement of the trap up the sides of the ball. Thus, the ball is less likely to be ejected from the towball receiver body 12 since there is no rolling or pitching motion of the trap around the ball. The trap 26 is always held under the cheek 36 of the towball 22 which is a more secure hold. The other bearings 70 and 93 provide more secure universal joint-style rotation about the other axes.

[074] In this specification, where a document, act or item of knowledge is referred to or discussed, this reference or discussion is not an admission that the document, act or item of knowledge or any combination thereof was at the priority date: (a) part of common general knowledge; or (b) known to be relevant to an attempt to solve any problem with which this specification is concerned.

[075] The word ‘comprising’ and forms of the word ‘comprising’ as used in this description do not limit the invention claimed to exclude any variants or additions.

[076] Modifications and improvements to the invention will be readily apparent to those skilled in the art. Such modifications and improvements are intended to be within the scope of this invention.

Claims (20)

1. THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS: ) 1. A coupling for coupling a towed vehicle to a towing vehicle, the coupling including: a towball receiver body including a towball receiver void disposed within the towball receiver body, the towball receiver void including a contoured internal wall for cooperating with a towball; a locking element including a contoured trapping surface and movable between a stowed position and a deployed position such that when the locking element is disposed in the stowed position, the trapping surface conforms to the contoured internal wall of the towball receiver void so as to form a portion of the contoured internal wall, and when the locking element is disposed in the deployed position, at least a portion of the contoured trapping surface is spaced from the contoured internal wall and extending into the towball receiver void a selected distance so as to substantially abut a cheek of the towball to inhibit release of the towball from the towball receiver void; a handle which is operatively connected to the locking element to move the locking element between the stowed position and the deployed position; and a keeper operatively connected to the handle, such that it is configured to selectively interengage therewith to selectively keep the locking element in the stowed and the deployed positions.
2. 2. The coupling in accordance with claim 1 wherein the handle includes a biasing element to bias the locking element from the stowed position to the deployed position.
3. 3. The coupling in accordance with claim 1 or 2 wherein the handle includes a rotor operatively connected to the locking element such that rotation of the rotor causes movement of the locking element.
4. 4. The coupling in accordance with claim 3 wherein the rotor and the locking element are mounted to a common shaft having a common axis about which they are configured to rotate so as to move the locking element between the stowed and deployed positions.
5. 5. The coupling in accordance with claim 4 wherein the common axis is a roll axis.
6. 6. The coupling in accordance with any one of claims 1 to 5 wherein the keeper is operatively mounted to the towball receiver body so as to be movable between a keeping position in which the keeper can selectively keep the handle in a position where the locking element is kept in either the stowed or deployed position, and a release position where the handle is free to move the locking element with the bias of the biasing element to the deployed position and against the bias of the biasing element to the stowed position.
7. 7. The coupling in accordance with any one of claims 3 to 6 wherein a cam is provided on the rotor on a circumference thereof, the cam including two spaced-apart radially- extending shoulders at either end thereof to facilitate keeping the rotor in either the stowed or the deployed positions. )
8. 8. The coupling in accordance with claim 7 wherein the cam surface is configured to receive the keeper, so that the keeper can run thereon between the stowed and deployed positions.
9. 9. The coupling in accordance with claim 8 wherein a first one of the radially-extending shoulders of the cam is shorter than the second one of the radial shoulders of the cam.
10. 10. The coupling in accordance with any one of claims 6 to 9 wherein the keeper is biased to the keeping position by a keeper biasing means.
11. 11. The coupling in accordance with any one of claims 6 to 10 wherein the keeper is in the form of an arm mounted on the towball receiver body and is configured to pivot between the keeping position and the release positions.
12. 12. The coupling in accordance with any one of claims 1 to 11 further including a lock self-actuator operatively connected to the keeper, the lock self-actuator including a distal end and being movable between a standby position and an actuation position, wherein the keeper keeps the distal end of the lock self-actuator in the receiver void to adopt the standby position, the arrangement being such that when a towball is received into the towball receiver void, the lock self-actuator is driven by the towball against the keeper to the actuation position to move the keeper out of interengagement with the handle, so that the locking element can move between the stowed position and the deployed position.
13. 13. The coupling in accordance with claim 12 wherein the distal end of the lock selfactuator extends into the void a selected distance from a ceiling of the towball receiver void so that the towball is disposed substantially within the towball receiver void before the keeper moves to the actuation position.
14. 14. The coupling in accordance with claim 13 wherein a proximal portion of the lock selfactuator extends through the ceiling of the receiver void so as to be accessible from an outer portion of the towball receiver body.
15. 15. The coupling in accordance with claim 12,13 or 14 wherein when the lock selfactuator is moved to the actuation position, the keeper is moved to the release position in which the keeper releases the locking element from the stowed position.
16. 16. The coupling in accordance with any one of claims 1 to 15 wherein the contoured internal wall includes a generally spherical wall portion for cooperating with a ball portion of the towball and a collar for cooperating with a flange of the towball, the collar being disposed below the generally spherical wall portion, and the arrangement being such that when the coupling is coupled to the main body of the towball, the generally spherical wall portion and ^ collar cooperate with the towball so that angular rotation of the coupling about the towball is limited to angular rotation about a yaw axis.
17. 17. The coupling in accordance with claim 16 wherein a yoke is provided to mount the towball receiver body to the towed vehicle, the yoke including parallel arms and a connecting base to connect the parallel arms together, the yoke providing a pivot about a roll axis.
18. 18. The coupling in accordance with claim 17 wherein the parallel arms include pivoting ends to connect to the towball receiver body such that the pivoting ends provide a pivoting axis which is a pitch axis transverse to the vehicle, so that the coupling can pitch about that pitch axis.
19. 19. The coupling in accordance with any one of claims 1 to 18 wherein the keeper is further articulated in that it includes a pivoting keeping flap.
20. 20. The coupling in accordance with claim 19 wherein the pivoting keeping flap is adapted to extend below the keeper arm.