AU2009202767A1 - Load sensing improvements - Google Patents

Description

59832 HKS:JO P/00/011 Regulation 3.2 AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT ORIGINAL Name of Applicant: JLSN PTY LTD Actual Inventor: JEFFREY KENDALL Address for Service: COLLISON & CO.,117 King William Street, Adelaide, S.A. 5000 Invention Title: LOAD SENSING IMPROVEMENTS Details of Associated Provisional Application: Australian Patent Application No. 2008903513 dated 9 July 2008 The following statement is a full description of this invention, including the best method of performing it known to me/us: 2 LOAD SENSING IMPROVEMENTS TECHNICAL FIELD This invention relates to load sensing being to both a method of load sensing and to an arrangement which can be used to provide useful load information in relation to vehicles to be towed and also in combination with a towing vehicle. BACKGROUND OF THE INVENTION When towing a vehicle being a piece of equipment requiring a second vehicle to propel it the use of a ball type coupling may be employed to connect the towing vehicle to the towed vehicle. The amount of downward or upward force exerted on a towing vehicle by the towed vehicle can influence the handling characteristics of both the towing vehicle and the towed vehicle and, if inappropriate, can cause difficulties and in fact serious accidents. In some countries of the world towing hitches can involve a coupling which provides a cowl with a lower most open spherical cavity which is secured to the vehicle to be towed and this fits over a generally spherical head which is attached to a tow bar of a towing vehicle. The coupling can include an interlocking lip which is usually spring loaded and fits beneath the spherical shape of the head when in a locking position. A difficulty with such an arrangement is that there may be some slack between the cowl and the head and there is often therefore provided a screw threaded rod that passes through the cowl and can engage against the head when in an interlocked position with the cowl and thIs acts to reduce slack and therefore backlash.

3 OBJECT OF THE INVENTION Measuring the load presented to the towing vehicle has been always difficult. I propose a way in which the weight can be relatively quickly and accurately measured without incurring high costs. An object therefore is to provide a method , an assembly and an apparatus which can assist in providing a weighing of a towed vehicle coupling presented weight or at the least provide the public with a useful alternative. SUMMARY OF THE INVENTION In one form of this invention it can be said to reside in a towable vehicle with a forward most coupling having a cowl with a lower most open cavity to receive a towball of a towing vehicle, and having extending through the wall of the cowl a threaded aperture and a load sensor screwably engaging through the threaded aperture with an end adapted to be positioned to engage with a lifting pressure the towball and provide a load measure thereby In a further alternative the invention can be said to reside in a combination being a towable vehicle with a forward most coupling having a cowl with a lower most open cavity and a received a towball of a towing vehicle therein, and having extending through the wall of the cowl a threaded aperture and a load sensor screwably engaging through the threaded aperture with an end positioned to engage with a lifting pressure the towball and provide a load measure thereby. in a further alternative form the invention can be said to reside in a method of measuring a hitch load between a towed and towing vehicle where there is a towable vehicle with a forward most coupling having a cowl with a lower most open 4 cavity and a received towball of a towing vehicle therein, the method including the steps of threading through a threaded aperture in a wall of the cowl a load sensor to an extent that the load sensor engages the towball and effects a lifting force to thereby provide a load measure between the two parts. In a further alternative the invention can be said to reside in a load sensing device for a ball type trailer coupling having an adaptor to adapt to a coupling, a plunger or probe to transmit force from the ball through a coupling, a body to receive the plunger or probe and house a piston, a piston to compress hydraulic fluid in the body cavity, a visual display mounted in the body end cap to display a readout relating to a load placed on the coupling or a pressure sensor or an electronic load cell mounted in the body to transmit a readout or signal to a remote display, light, visual display or audible alarm. In practice there is an anti-rattle threaded aperture and stud which can be removed and replaced with a load sensing probe. As the alignment of the probe may be at an angle to the vertical some calibration is used to provide some greater accuracy of a load measurement. This invention assists the driver of the towing vehicle by approximately indicating the downward force provided at the connection between the coupling and the tow ball. A towed vehicle may be but is not limited to a trailer, caravan or a piece of machinery such as a mobile air compressor or any other equipment fitted with a tow hitch designed to connect to a towing vehicle via a tow ball coupling. The anti-rattle stud is a threaded rod with one end protruding into the area of the coupling where the ball is located to prevent backlash between the ball and the coupling. The stud can be removed and replaced by a load sensor taking place of the anti-rattle stud and also providing a reading from a gauge or signal to a display unit indicating the downward force on the tow ball or a pre-determined operating load indicated by a visual or audible alarm or light. If an anti-rattle stud is not fitted to a coupling a threaded hole can be drilled and cut through a top wall of the coupling so the load probe can be installed in the same manner as detailed herein. In a further form the location of a load sensor could be incorporated when there is manufacture of the coupling. There is disclosed herein a load sensing device consisting of an adapter housing, coupling, body, plunger, piston, seal, end cap, visual display, ball and a pressure switch. The adapter is fixed into a trailer coupling with the plunger or probe located inside the adapter in such a way that the plunger or probe rests on an upper outer surface of a tow ball located inside the coupling transferring forces via the plunger or probe into a body forming a part at the opposite end of the adapter. The body consists of a chamber directly above the adapter that the plunger or probe protrudes into. One embodiment consists of a piston and seal located inside the chamber resting against the plunger or probe, A cavity above the piston and seal can be filled with a fluid suitable to activate a pressure gauge or a pressure sensing device such as a pressure switch, transducer or other device sensitive to pressure change located in the end of the cavity. When force is applied to the plunger or probe by the tow ball located in the coupling the force is transferred to the piston and seal located in the cavity causing the pressure in the cavity to rise. The rise in pressure is detected by a gauge or pressure sensing device located in the end of the cavity. If a pressure sensing device is used it may be used to send a signal to a display unit. The display unit would then indicate a pressure reading that may be converted into a weight, or a visual display such as a light or audible alarm or all of the above indicating that a weight range has been met or exceeded. Another aspect of the invention can reside in a load cell located inside the chamber that the plunger protrudes through resting against the plunger or probe. When a force is transferred from the tow ball to the load cell by the plunger or probe a signal could bise transmitted to a display unit that indicates a pressure reading that is converted into a weight, or a visual display such as a light or audible alarm or all of the above. BRIEF DESCRIPTION OF THE DRAWINGS A preferred form of the invention will now be described by way of example with reference to the accompanying drawings wherein: Figure 1 is a schematic sectional side elevation of the hydraulic load sensing device installed onto a ball type towing coupling fitted with a gauge being the first configuration. Figure 2 is a schematic sectional side elevation of the hydraulic load sensing device installed onto a ball type towing coupling fitted with a pressure sensing device such as a pressure switch, transducer or any other device that could determine a pressure change that may be converted into a weight, or a visual display such as a light or audible alarm or all of the above being the second configuration.

7 Figure 3 is a schematic sectional side elevation of the load cell load sensing device installed onto a ball type towing coupling capable of transmitting data to visual display being the third configuration. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In the accompanying drawings there is a schematically depicted hydraulic load sensing device installed onto a ball type towing coupling fitted with a visual display Figure 1. An adaptor 1 is located into a coupling 2. A body 3 is located on the opposite end of the adaptor 1. The plunger or probe 4 is located from inside the coupling 2 into the adaptor 1. A piston 5 with a seal 6 fitted is inserted into the body 3. An end cap 7 is located into the body 3. A cavity 8 is filled with hydraulic fluid or grease. A visual display 9 is located in the end cap 7. Vertical force exerted on a tow ball 10 by the coupling 2 is transferred via the plunger or probe 4 to the piston 5. The hydraulic fluid or grease located in the cavity 8 will be compressed as a result of vertical forces exerted on the ball 10 by the coupling 2 transmitted to the piston 5 through the plunger or probe 4. A pressure change will be indicated on the visual display 9. Figure 2 also shows an adaptor 1 is located into a coupling 2. A body 3 is located on the opposite end of the adaptor 1. A plunger 4 is located from inside the coupling 2 into the adaptor i. A piston 5 with a seal 6 is fitted and is inserted into a body 3. An end cap 7 is located into the body 3. A cavity 8 is filled with hydraulic fluid or grease.

8 A pressure switch, transducer or any other device that can determine a pressure change that may be converted into a readout or visual display such as a light or audible alarm or all of the above 11 is fitted into the end cap 7 transmitting a signal to a visual display. Figure 3 also shows an adaptor 1 is located into a coupling 2. A body 3 is located on the opposite end of the adaptor 1. A plunger or probe 4 is located from inside the coupling 2 into the adaptor 1. A load cell load sensing module 12 is located inside the body 3 resting against the plunger 4. Vertical forces exerted on the ball 10 by the coupling 2 transmitted to the piston 5 through the plunger or probe 4. A read out could be indicated on a separate visual display. What is now seen is how convenient a load measurement can be and the concept has been found to be of great benefit.

Claims (8)

1. A towable vehicle with a forward most coupling having a cowl with a lower most open cavity to receive a towball of a towing vehicle, and having extending through the wall of the cowl a threaded aperture and a load sensor screwably engaging through the threaded aperture with an end adapted to be positioned to engage with a lifting pressure the towball and provide a load measure thereby.

2. In combination, a towable vehicle with a forward most coupling having a cowl with a lower most open cavity and a received towball of a towing vehicle therein, and having extending through the wall of the cowl a threaded aperture and a load sensor screwably engaging through the threaded aperture with an end positioned to engage with a lifting pressure the towball and provide a load measure thereby.

3. A method of measuring a hitch load between a towed and towing vehicle where there is a towable vehicle with a forward most coupling having a cowl with a lower most open cavity and a received towball of a towing vehicle therein, the method including the steps of threading through a threaded aperture in a wall of the cowl a load sensor to an extent that the load sensor engages the towball and effects a lifting force to thereby provide a load measure between the two parts.

4. A load sensing device for a ball type trailer coupling having an adaptor to adapt to a coupling, a plunger to transmit force from the ball through a coupling, a body to receive the plunger and house a piston, a piston to compress the hydraulic fluid in the body cavity, a visual display mounted in 10 the body end cap to display a readout relating to a load placed on the coupling or a pressure sensor or an electronic load cell mounted in the body to transmit a readout or signal to a remote display, light, visual display or audible alarm.

5. A load sensing device for a ball type trailer coupling substantially as described in the specification with reference to and as illustrated by figure 1 of the accompanying drawings.

6. A load sensing device for a ball type trailer coupling substantially as described in the specification with reference to and as illustrated by figure 2 of the accompanying drawings.

7. A load sensing device for a ball type trailer coupling substantially as described in the specification with reference to and as illustrated by figure 3 of the accompanying drawings.

8. A method of measuring a hitch load between a towed and towing vehicle where there is a towable vehicle with a forward most coupling having a cowl with a lower most open cavity and a received towball of a towing vehicle therein substantially as described in the specification. With reference to and as illustrated by each of the attached drawings.