AU2008264181A1

AU2008264181A1 - Releasable Tow Hitch

Info

Publication number: AU2008264181A1
Application number: AU2008264181A
Authority: AU
Inventors: Michael Maud
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-12-24
Filing date: 2008-12-24
Publication date: 2009-07-09

Description

P/00/011 28/5/91 Regulation 3.2 AUSTRALIA Patents Act 1990 ORIGINAL COMPLETE SPECIFICATION STANDARD PATENT Name of Applicant: Michael Maud Actual Inventor Michael Maud Address for service is: WRAYS Ground Floor, 56 Ord Street West Perth WA 6005 Attorney code: WR Invention Title: Releasable Tow Hitch The following statement is a full description of this invention, including the best method of performing it known to me: 1 2 Releasable Tow Hitch Field of the Invention The present invention relates to a tow hitch. Background Art 5 A tow hitch is a device attached to a chassis of a tow vehicle for towing a trailing vehicle such as a trailer or caravan. The tow hitch typically incorporated in a tow bar or tow hitch system and includes a tow ball for allowing the trailer or caravan to pivot relative to the vehicle. It is desirable to determine how much of the weight of the caravan or trailer is being supported by the tow hitch to ensure that the tow 10 vehicle is not over loaded and the trailing vehicle is loaded correctly in relation to the tow vehicle. The above discussion of the background art is intended to facilitate an understanding of the present invention only. The discussion is not an 15 acknowledgement or admission that any of the material referred to is or was part of the common general knowledge as at the priority date of the application. Throughout the specification and claims, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be 20 understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers. Disclosure of the Invention 25 According to an aspect of the invention there is provided a tow hitch for attaching a trailing vehicle to a tow vehicle, the tow hitch comprising a body having means for providing an indication of the weight applied to the tow hitch by the trailing vehicle and attachment means for releasably attaching the tow hitch to the tow vehicle.

3 Preferably, the means for providing an indication of the weight applied to the tow hitch by the trailer comprises strain gauges. Preferably, the strain gauges are releasable connected to a digital gauge for providing an indication of the weight applied to the tow hitch by the trailing vehicle. 5 Preferably, the tow hitch further comprises a cover for covering the strain gauges. Preferably, the tow hitch further comprises a tow ball for receiving the trailing vehicle. Preferably, the means for releasable attaching the tow hitch to the vehicle comprise a bar adapted to be slidably received into a tow hitch housing attached 10 to the vehicle. Preferably, the bar and the tow hitch housing comprise holes for receiving a locking pin in order to secure in use the tow hitch to the tow vehicle. In another arrangement there is provided a tow bar includes a hollow body and a lever having a first end pivotally attached to the body, wherein the tow ball is 15 attached to a second end of the lever, the housing having a resilient means supporting the lever to substantially maintain the lever level in use and wherein the resilient means is operatively connected to an indication means which provides an indication of the weight being supported by the tow ball in use. The body includes a rear wall having an aperture through which the lever extends. 20 The resilient means is preferably an airbag. Brief Description of the Drawings The present invention will be better understood by reference to the following description of several specific embodiment thereof as shown in the accompanying drawings, in which: 4 Figure 1 is a side view of a tow bar according to a first embodiment of the present invention; Figure 2 is a front view of the tow bar of figure 1; Figure 3 is a perspective view of the tow bar of figure 1; 5 Figure 4 is a schematic side elevation view of a tow bar according to a second embodiment of the present invention; and Figure 5 is a schematic side elevation view of a tow bar according to a third embodiment of the present invention. Best Mode(s) for Carrying Out the Invention 10 Figures 1 to 3 show a tow hitch 10 according to a first preferred embodiment of the present invention. The tow hitch 10 forms part of a tow hitch system mounted on a tow vehicle. The tow hitch 10 includes a body 11 which includes a first arm 31 which is substantially horizontal in use and a second arm 30 which extends upwardly and perpendicularly from a rear end 32 of the first arm 31. The body 11 15 is thus is substantially L-shaped when viewed from the side. The body 11 is hollow and includes a rear wall 25 having an upper aperture 23 and a lower aperture 24. The tow hitch 10 includes a lever 14 which extends from a front end 33 of the first arm 31 and rearwardly past the rear wall 25 through the lower aperture 24. The lever 14 is pivotally connected by a pivot bolt 13 at the 20 front end 33. A rear end of the lever 14 includes a tow ball 15 which is secured thereto by a nut 16. The tow ball 15 is thus able to move in a substantially vertical direction due to the pivotal attachment of the lever 14 at the front end 33. An airbag 17 is located within the body 11 beneath the lever 14 which maintains the lever 14 in a substantially level orientation. In the level orientation, the top surface 25 of the lever 14 preferably abuts the top edge of the lower aperture 24. The airbag 14 also measures weight loads on the tow ball 15 as further described below. The tow hitch 10 also includes a hollow rectangular tube 20 which extends from the top aperture 23 and forwardly to substantially above and past the front end 33 5 of the first arm 33. The tube 20 is secured to the body 11 and top aperture 23 by welding. The tube 20 is sized to fit into a typical Reece hitch assembly attached to the chassis of a vehicle. The tube includes an aperture 22 at its side wall for attaching to a Reece assembly. 5 The tow hitch 10 also includes a gauge 18 located on a side wall of the body 11. The gauge 18 is operatively connected to the airbag 17 and provides an indication of how much of the weight of the trailer or caravan is being supported by the tow ball 15 in use. In use, the tow hitch 10 is fitted to the chassis of vehicle to allow a trailer or 10 caravan to be attached to the tow ball 15 for towing. The airbag 17 substantially keeps the lever 14 horizontal irrespective of the weight being supported by the tow ball 15 for optimal towing, thus minimising adverse effects in the steering, handling and braking of the vehicle. At the same time, the airbag 17 also provides an indication of the weight being supported by the tow ball 15 via the gauge 18. 15 This allows the user to move loads within the trailer or caravan towards or away from the tow ball 15 (relative to the axle or axles of the trailer or caravan) to ensure that the tow ball 15 is not overloaded. The gauge 18 also thus provides an indication of the distribution of loads in the trailer or caravan. Figure 4 shows a second embodiment of a tow hitch 40 according to the present 20 invention. The tow hitch 40 includes an elongated body 41 having a rear end 42 and a front end 43. The front end 43 is shaped into a 50 mm square cross section tube for sliding into and attachment to Reece type tow hitches. The rear end 42 is shaped for attachment of a tow ball 44 which is attached thereto by a nut 47. 25 The body 41 of the tow hitch 40 includes strain gauges (not shown) arranged therein which are connectable to a digital gauge 45 via a detachable screw connector 46. In use, the tow hitch 40 is attached to the vehicle chassis as known (typically a tow hitch system such as a Reece type tow hitch as mentioned above) and a trailer or caravan is attached to the tow ball 44. Weight being supported by 30 the tow ball 44 will bend the body 41 slightly which is detected by the strain gauges. The body 41 thus acts as a load cell and the strain gauges provide a 6 measure of the weight being supported by the tow ball 44. The user can then rearrange loads in the trailer or caravan toward or away from the tow ball 44 as desired (thus also relative to the axle or axles of the tailer or caravan) to ensure that the tow bal is not overloaded. After measuring the load on the tow ball 44, 5 the gauge 45 can be disconnected via the connector 46 for storage. Figure 5a shows a tow hitch 40 according to a third embodiment of the invention. The tow hitch according to the third embodiment is similar to the tow hitch according second embodiment and similar reference numerals are used to identify similar parts. In this third embodiment the tow hitch 40 incorporates the strain 10 gauges within a protective cover 51. The tow hitch 40 according to the third embodiment includes an elongated body 41 having a rear end 42 and a front end 43. The front end 43 is shaped into a 50 mm square cross-section tube for sliding into and attachment to a tow hitch housing. The tow hitch housing may be of the Reece type tow hitches. The rear 15 end 42 comprises an opening for receiving, for example, a tow ball or any fastening means for attaching a trailer or caravan to the vehicle. Holes 53 are provided for receiving a locking pins once the rear end 42 is inserted in the tow bar housing which incorporates holes counterpart of holes 53 of the tow bar for securing the tow bar within the tow hitch housing. 20 Figure 5b shows a digital gauge to be electrically connected, via the detachable screw connector 46, to the strain gauges so as to obtain indication of the weight applied to tow hitch by the trailer. The present invention thus provides a tow hitch which provides an immediate measure of the load being supported by the tow ball. This allows the user to 25 move loads in the trailer or caravan if required, to reduce or increase the load on the tow ball and ensure that the tow ball is no overloaded. Although a preferred embodiment of the present invention has been described, it will be apparent to skilled persons that the invention can be embodied in other forms or that modifications can be made to the above embodiments. For example, 30 the tow hitch 40 may not necessarily be a bar or tube as shown in figures 4 and 5.

7 The tow hitch may take any shape and comprise any type attachment means at each end for attachment to the tow vehicle and to the trailing vehicle.

Claims

1. A tow hitch for attaching a trailing vehicle to a tow vehicle, the tow hitch comprising a body having means for providing an indication of the weight applied to the tow hitch by the trailing vehicle and attachment means for 5 releasably attaching the tow hitch to the tow vehicle.

2. A tow hitch according to claim 1 wherein the means for providing an indication of the weight applied to the tow hitch by the trailing vehicle comprises strain gauges.

3. A tow hitch according claim 2 wherein the strain gauges are releasable 10 connected to a digital gauge for providing an indication of the weight applied to the tow hitch by the trailer.

4. A tow hitch according to any of claims 2 and 3 further comprising a cover for covering the strain gauges.

5. A tow hitch according to any of the previous claims further comprising a 15 tow ball for receiving the trailing vehicle.

6. A tow hitch according to any of the previous claims wherein the means for releasable attaching the tow hitch to the tow vehicle comprise a bar adapted to be slidably received into a tow hitch housing attached to the vehicle. 20

7. A tow hitch according to claim 6 wherein the bar and the tow bar housing holes for receiving a locking pin in order to secure in use the tow hitch to the vehicle.

8. A tow hitch substantially as herein described with reference to the accompanying drawings. 25