GB2599755A

GB2599755A - A stability system for a vehicle

Info

Publication number: GB2599755A
Application number: GB2106191.6A
Authority: GB
Inventors: John Hall Andrew
Original assignee: Macs Truck Sales Ltd
Current assignee: Macs Truck Sales Ltd
Priority date: 2021-04-29
Filing date: 2021-04-29
Publication date: 2022-04-13
Anticipated expiration: 2041-04-29
Also published as: GB2599755B; GB202106191D0

Abstract

A stability system 10 comprises an actuator unit 200, centred on a longitudinal axis 202, with a housing 300; a support leg 400 and a foot unit 500. The support leg has a head end 402 located within the housing and a foot end 404, the support leg extends out of an opening 310 in the housing. The support leg and housing are slideable relative to each other along the longitudinal axis. The foot unit has a coupling portion 502 coupled to the foot end of the support leg and a free end 504 distal to the coupling portion. The foot unit and support leg are moveable relative to one another along the longitudinal axis such that the distance between the head end of the support leg and the free end of the foot unit are between set limits, d1 and d2, which may be determined, in part, by the length of the resilient member 410, which may be a spring. A sensor 102 may be used to determine between a loaded and unloaded condition of the vehicle.

Description

A STABILITY SYSTEM FOR A VEHICLE

The present disclosure relates to a stability system for a vehicle.

Background

Some vehicles carry lifting equipment, for example a crane or cradle for lifting loads. It is common to fit these vehicles with a stability system to inhibit the vehicle from falling over if the lifting equipment moves a load to an extended position, for example out to one side of the vehicle. Such stability systems may include legs (for example hydraulic rams) which extend from the sides and or ends of the vehicle.

Fig. 1 illustrates a vehicle fitted with a number of actuator units, labelled Al to A6, which each comprise a support leg that is actuated by its respective actuator unit. In this example, two actuator units Al, A2, are located at the front of the vehicle, and further actuator units A3 to A6 are provided on the sides of the vehicle.

Some conventional systems include sensors which feed information to a control unit indicate whether a load is applied to each support leg. If no load is applied to leg, the control unit will infer that the leg is not is not positioned on the ground, and hence not providing support. This may trigger an alarm and or prevent the lifting equipment from operating, or require the configuration of the equipment to be adjusted, until a signal is received that indicates the leg is in contact with the ground. This is, of course, an important safety feature.

In some scenarios, the load reducing on a leg may not be symptomatic of an impending instability, and hence triggering of the alarm and/or preventing/limiting use of the equipment provides an unnecessary limitation on the user.

For example, consider the arrangement of Fig. 1. In an example manoeuvre, the lifting equipment 12 moves a load from position 1 (P1) at the rear of the vehicle, in an arc around to position 2 (P2) over one side of the vehicle, and then on to position 3 (P3) towards the front of, and overhanging, the vehicle. During this manoeuvre the load on the legs of actuator units Al, AS and AS will be increased relative to the support legs of actuator units A2, A3, A4. Hence, in an example system of the related art, the control unit may determine that, as a consequence of the load on the legs of the actuator units A2, A3, A4 being below a predetermined value, then an -2 -alarm may sound and/or the lifting equipment 12 be limited to be unable to complete the manoeuvre. For example, in an example system of the related art, the user may be required to perform the lifting operation by keeping the load closer to the vehicle side to prevent the alarm from triggering. However, in such a scenario there may be no risk to stability during the manoeuvre if adequate stability is provided by support legs Al, A5, A6, so the limiting actions of the control unit performs no useful function and merely inconvenience the user.

Hence a stability system which is operable to maintain the stability of a vehicle during a lifting operation and reduces instances of false instability Indications, is highly desirable.

Summary

According to the present disclosure there is provided apparatus and method as set forth in the appended claims. Other features of the invention will be apparent from the dependent claims, and the description which follows.

Accordingly there may be provided a stability system (10) for a vehicle (20) comprising an actuator unit (200) centred on a longitudinal axis (202). The actuator unit (200) may have a housing (300), a support leg (400) and a foot unit (500). The support leg (400) may have a head end (402) and a foot end (404). The head end (402) may be located within the housing (300) with the support leg (400) extending from the head end (402) to the foot end (404), and the foot end (404) may extend out of an opening (310) in the housing (300). The support leg (400) and housing (300) may be slideable relative to each other along the longitudinal axis (202). The foot unit (500) may have a coupling portion (502) coupled to the foot end (404) of the support leg (400) and a free end (504) distal to the coupling portion (502). The foot unit (500) and support leg (400) are moveable relative to one another along the longitudinal axis (202) such that the distance between the head end (402) of the support leg (400) and the free end (504) of the foot unit (500) is at most a first distance (dl) and no less than a second distance (d2), the second distance being smaller than the first distance.

The first distance (d1) may be the fully extended length of the foot unit (500) and support leg (400) assembly. The second distance (d2) may be the minimum length of the foot unit (500) and support leg (400) assembly. -3 -

The housing (300) may define a hollow chamber (320). The support leg (400) may define a hollow chamber (422), the support leg (400) being closed at the head end (402) and defining an aperture (420) at the foot end (404) which receives the coupling portion (502) of the foot unit (500).

The free end of the foot unit (500) may comprise a base portion (520), which extends to the coupling portion (502). The coupling portion may comprise an end wall (540), an outer (i.e. side) wall (506) and a spigot (508), the outer wall (506) and spigot (508) extending from the end wall (540), and the outer wall (506) bounds, and is spaced apart from, the spigot (508) to define an annular cavity (510) which extends around the spigot (508). The spigot (508) and support leg aperture (420) may be configured so that the spigot (508) fits through the support leg aperture (420) to enter the support leg hollow chamber (422). The foot unit cavity (510) may be configured to receive the support leg (400), and to allow the support leg to slide along the cavity (510) until it reaches the end wall (540) such that when the foot end (404) of the support leg is engaged with the end wall (540), the head end (402) of the support leg (400) and the free end (504) of the foot unit (500) may be spaced apart by the second distance (d2).

The coupling portion (502) outer (i.e. side) wall (506) may define a slot (526) extending from a first stop end (528) furthest from the free end (504) to second stop end (530) closest to the free end (504). A guide pin (512) may extend from the support leg (400) through the slot (526) such that when the guide pin (512) is engaged with the first stop end (528), the head end (402) of the support leg (400) and the free end (504) of the foot unit (500) are spaced apart by the first distance (d1).

The stability system (10) may further comprise a vehicle mount (100). The housing (300) may be carried by the vehicle mount (100) such that the actuator unit (200) and vehicle mount (100) have an unloaded configuration (Cl) and a loaded configuration (C2).

The housing (300) may be carried by the vehicle mount (100) so that it is limited to be slideable relative to the vehicle mount (100) between a first position and a second position along the longitudinal axis (202) between the unloaded configuration (Cl) and the loaded configuration (C2) respectively.

The stability system (10) may further comprise an indicator (104) which is configured such that when the head end (402) of the support leg (400) and the free end (504) of the foot unit (500) are spaced apart by at least the first distance (dl), the indicator (104) indicates the actuator unit -4 - (200) is in the unloaded configuration (Cl). When the free end (504) of the foot unit (500) and head end (402) of the support leg (400) are spaced apart by less than the first distance (d1) the indicator (104) may indicate the actuator unit (200) is in the loaded configuration (C2).

The stability system (10) may further comprises a sensor (102) operable to generate a signal which indicates the value of indicator distance (ID1, ID2) measured between a reference point on the housing (600) and the vehicle mount (100), and hence indicates if the housing (300) is the unloaded configuration (Cl) or the loaded configuration (C2).

The stability system (10) may further comprise a control unit (106) operable to control the actuator unit (200) to induce a force on the support leg (400).

The control unit (106) may be operable to control the actuator unit (200) in response to the signal which indicates the value of indicator distance (101) to increase the force on the support leg (400) if the signal changes from indicating loaded configuration (C2) to unloaded configuration (Cl).

The stability system (10) may further comprise a resilient biasing member (410) housed within the support leg (400) and extending along the inside of the support leg (400). The resilient biasing member (410) may be provided between the coupling portion (502) of the foot unit (500) and the support leg (400).

The support leg (400) may comprise a support base (430) which extends along the inside of the support leg (400) to co-operate with one end of the resilient biasing member (410). The other end of the resilient biasing member (410) may co-operate with a face of the foot unit spigot (508) which faces the head end of the support leg (400).

The support leg (400), resilient biasing member (410) and foot unit (500) may be co-axial and/or concentric and centred on the longitudinal axis (208).

There may also be provided a vehicle comprising a stability system (10) according to the present disclosure. -5 -

There may also be provided a method of operation of a stability system (10) for a vehicle (20), the method compromising the steps of when the head end (402) of the support leg (400) and the free end (504) of the foot unit (500) are spaced apart by at least a first distance (dl), the indicator (104) indicates the actuator unit (200) is in the unloaded configuration (Cl); and when the free end (504) of the foot unit (500) and head end (402) of the support leg (400) are spaced apart by less than the first distance (d1) the indicator (104) indicates the actuator unit (200) is in the loaded configuration (C2).

The method may further comprise the step of the sensor (102) generating a signal which indicates the value of indicator distance (ID1) measured between a reference point on the housing (600) and the vehicle mount (100).

The method may further comprise the steps of in response to the signal which indicates the value of indicator distance (ID1), and if the signal changes from indicating loaded configuration (C2) to unloaded configuration (Cl), the control unit (106) controls the actuator unit (200) to increase the force on the support leg (400) until the sensor (102) generates a signal which indicates the housing (300) and vehicle mount (100) are in the loaded configuration (C2).

Hence there is provided a stability system which is operable to maintain the stability of a vehicle during a lifting operation and reduces instances of false instability indications.

Brief Description of the Drawings

Examples of the present disclosure will now be described with reference to the accompanying drawings, in which: Figure 1 shows a plan view of a vehicle comprising a stability system; Figure 2 is an end view of a vehicle with a stability system according to the present disclosure in an unloaded configuration; Figure 3 is an end view of the vehicle shown in Figure 2 with the stability system in a first loaded configuration; Figure 4 is an end view of the vehicle shown in Figure 2 with the stability system in a second loaded configuration; Figure 5 is an end view of the vehicle shown in Figure 2 tilted to one side; Figure 6 is an end view of the vehicle shown in Figure Stilted furtherthat shown in Figure 5; -6 -Figure 7 shows a range of states of the support assembly; Figure 8 shows a side pad sectional view of a support assembly of the stability system; Figures 9, 10 show different views of the support assembly; Figure 11 shows an end view of a coupling portion of a foot unit of the support assembly; Figure 12 shows a side view the foot unit of the support assembly; Figure 13 shows an end view of a base portion of the foot unit of the support assembly; Figure 14 shows a first side view of the foot unit of the support assembly; Figure 15 shows a second side view the foot unit of the support assembly; and Figure 16 shows an isometric view of the foot unit.

Detailed Description

Fig. 1 shows a vehicle 20 to which a stability system 10 of the present disclosure may be applied. One or more of the actuator units Al to A6 may comprise the features of the stability system of the present disclosure. For the avoidance of doubt, the stability system 10 of the present disclosure may be fitted in a different number, arrangement, location and combination to that shown in Fig. 1. Fig. 1 merely shows an example to provide context so the reader may understand how the stability system may be used in a non-limiting example with a vehicle fitted with lifting apparatus. The vehicle may be a truck or other wheeled vehicle, or trailer, or any other platform which requires adjustable stability. By way of non-limiting example, the stability system will be described with reference to actuator units Al and A2 located at the front of the vehicle.

Figs. 2 to 6 show a front view of the vehicle 20 with two actuator units 200 (i.e. actuator units Al, A2) shown mounted to the end of the vehicle 20 by a vehicle mount 100. The vehicle has tyres/wheels 32 which sit on a supporting surface (e.g. the ground, a substrate). Fig. 7 shows a range of states 7A, 7B, 7C of the support assembly, with figure 7A showing the support assembly in a retracted state, Fig. 7B showing the support assembly in an extended state, and Fig. 7C showing the support assembly in a fully compressed state.

As shown in Figs. 2 to 7, the stability system 10 comprises an actuator unit 200 centred on a longitudinal axis 202. The actuator unit 200 has a housing 300, a support leg 400 and a foot unit 500. The actuator unit 200 may be a hydraulic system, with the support leg 400 provided as a hydraulic ram. -7 -

As shown in Figs. 2, 3, 4 each actuator unit 200 may be mounted such that, in normal use, the housing 300 is above the foot unit 500 (for example, vertically).

The housing 300 is carried by (e.g. mounted to) a vehicle mount 100 such that the actuator unit 200 and vehicle mount 100 have an unloaded configuration Cl (as illustrated in Fig. 7A) and a loaded configuration C2 (as illustrated in Figs. 7B, 7C). The vehicle mount 100 couples the actuator unit 200 to the vehicle 20. For example, the vehicle 100 is configured to be coupled to a structural feature (for example chassis) of the vehicle 20.

The housing 300 is carried by the vehicle mount 100 so that it is limited to be slideable (e.g. moveable) relative to the vehicle mount 100 between a first position and a second position along the longitudinal axis 202 between the unloaded configuration Cl and the loaded configuration C2 respectively.

Since the actuator unit 200 is mounted with the housing 300 above the foot unit 500, with the foot unit 500 spaced apart from the supporting substrate/ground, the actuator unit 200 will come to rest in the mount 100 in the unloaded configuration Cl.

The support leg 400 has a head end 402 and a foot end 404. That is to say, the support leg 400 extends from the head end 402 to the foot end 404. The length of the support leg 400 may be defined by the distance between the head end 402 to the foot end 404. In use, the foot end 404 is located between the head end 402 and the ground/substrate. The housing 300 defines a hollow chamber 320. The head end 402 is located within the housing 300 with the support leg 400 extending from the head end 402 to a foot end 404. The foot end 404 extends out of an opening 310 in the housing 300. The support leg 400 and housing 300 are slideable relative to each other along the longitudinal axis 202.

The support leg 400 defines a hollow chamber 422, the support leg 400 being closed at the head end 402 and defining an aperture 420 at the foot end 404 which is configured to receive a coupling portion 502 of the foot unit 500. The aperture 420 at the foot end 404 may be configured to receive a part of the coupling portion 502 of the foot unit 500.

The foot unit 500 is illustrated in Figures 11 to 16. Figures 11, 13 show end views of the coupling portion 502. Figure 12 shows a side view the foot unit 500. -8 -

The foot unit 500 further comprises a free end 504 distal to the coupling portion 502. The foot unit 500 comprises a first end 550 (i.e. the free end 504) spaced apart from a second end 552 at the coupling portion 502 along the longitudinal axis 202. The first end 550 is defined by a base portion 520 for engagement with a substrate, for example the ground. Figure 13 shows an end view of a base portion 520. As shown in the examples, the base portion may be curved. For example, the base portion 520 may be part spherical. The base portion 520 is coupled to the coupling portion 502. A neck 424 may extend from (i.e. between) the base portion 520 and the coupling portion 502. The base portion 520 may be used with a spacer/platform (not shown) located between it and the substrate.

As shown in Figures 14, 15 the coupling portion may comprise an end wall 540, an outer wall 506 and a spigot 508. The outer wall 506 and spigot 508 extend from the end wall 540, and the outer wall 506 bounds, and is spaced apart from, the spigot 508 to define an annular cavity 510 which extends around the spigot 508.

The spigot 508 and support leg aperture 420 are configured so that the spigot 508 fits through the support leg aperture 420 to enter the support leg hollow chamber 422. That is to say, the spigot 508 is configured for engaging with an aperture 420 in the foot end 404 of the support leg 400. Hence the aperture 420 at the foot end 404 of the support leg 400 may be configured to receive the spigot 508.

The foot unit cavity 510 is configured to receive the support leg 400, and to allow the support leg 400 to slide along the cavity 510 until it reaches the end wall 540. The cavity 510 is configured to receive an end of the support leg 400 and so the foot unit 500 can slide relative to the support leg 400. The end wall 540 limits the extent to which the support leg 400 can slide into the foot unit 500. When the foot end 404 of the support leg is engaged with the end wall 540, the head end 402 of the support leg 400 and the free end 504 of the foot unit 500 are spaced apart by the second distance d2 (as shown in Fig. 7C).

There may also be provided a resilient biasing member 410 housed within the support leg 400 and extending along the inside of the support leg 400. The resilient biasing member 410 may be provided as a coiled spring. A support sleeve (not shown) may be provided around the resilient biasing member 410. The resilient biasing member 410 may be provided between, and hence operable to react against, the coupling portion 502 of the foot unit 500 and the support leg 400.

The resilient biasing member 410 may be provided between the spigot 508 of the foot unit 500 and the support leg 400. -9 -

The support leg 400 may comprise a support base 430 which extends along the inside of the support leg 400 to co-operate (i.e. engage) with one end of the resilient biasing member 410. The other end of the resilient biasing member 410 may co-operate (i.e. engage) with a face of the foot unit spigot 508 which faces the head end of the support leg 400.

The support leg 400, resilient biasing member 410 and foot unit 500 may be co-axial and/or concentric and centred on the longitudinal axis 208.

As shown in Figs. 2 to 8, 9, 10, 14, 16 the coupling portion 502 outer/side wall 506 defines a slot 526. The slot 526 may be aligned with the longitudinal axis 202. The slot may extend from a first stop end 528 furthest from the free end 504 to second stop end 530 closest to the free end 504. A guide member 512, for example a pin or bolt, extends from the support leg 400 through the slot 526.

Alternatively (not shown), the slot 526 may be provided in the wall of the support leg 400 and the guide pin 512 may extend from the coupling portion outer wall 506.

When the guide pin 512 is engaged with the first stop end 528, the head end 402 of the support leg 400 and the free end 504 of the foot unit 500 are spaced apart by a first distance dl (as shown in Fig. 7A). Hence the first stop end 528 limits the extent to which the support leg 400 can withdraw from the foot unit 500, and the end wall 540 of the coupling portion 502 limits the extent to which the support leg 400 can slide into the foot unit 500.

Thus, when assembled, the coupling portion 502 of the foot unit 500 is coupled to the foot end 404 of the support leg 400. Together, the foot unit 500 and coupling portion 502 form a support assembly 700, as shown in isolation in Figures 8, 9, 10.

The foot unit 500 and support leg 400 are moveable relative to one another along the longitudinal axis 202. The distance between the head end 402 of the support leg 400 and free end 504 of the foot unit 500 is variable. The distance between the head end 402 of the support leg 400 and free end 504 of the foot unit 500 is constrained to vary between limits by the slot 526 on the coupling portion outer wall 506 and the end wall 540 of the coupling portion 502. The distance between the head end 402 of the support leg 400 and the free end 504 of the foot unit 500 is at most the -10 -first distance dl (as shown in Fig. 7A) and no less than a second distance d2 (as shown in Fig. 7C), the second distance being smallerthan the first distance. Hence in normal operation (for example when assembled and undamaged), the distance between the head end 402 of the support leg 400 and the free end 504 of the foot unit 500 is at most the first distance dl (as shown in Fig. 7A) and no less than a second distance d2 (as shown in Fig. 7C), the second distance being smaller than the first distance.

The first distance dl may be the fully extended length of the foot unit 500 and support leg 400 assembly. Hence the first distance dl may be the length of the foot unit 500 and support leg 400 assembly between the head end 402 of the support leg 400 and the free end 504 of the foot unit 500 when the foot unit 500 and support leg 400 assembly is fully extended, for example as shown in Fig. 7A.

The second distance d2 is the minimum length of the foot unit 500 and support leg 400 assembly. Hence the second distance d2 is the length of the foot unit 500 and support leg 400 assembly between the head end 402 of the support leg 400 and the free end 504 of the foot unit 500 when the foot unit 500 and support leg 400 assembly is fully compressed (i.e. when the foot end 404 of the support leg 400 engages with the end wall 540 of the coupling portion 502), for example as shown in Fig. 7C.

The displacement distance (i.e. possible change in length) between the head and 402 the support leg 400 is limited to a predetermined value.

The displacement distance between the first distance dl and second distance d2 may be in the range of 25mm to 75mm. The displacement distance between the first distance dl and second distance d2 may be in the range of 35mm to 65mm. The displacement distance between the first distance dl and second distance d2 may be in the range of 45mm to 55mm. The displacement distance between the first distance dl and second distance d2 may be about 50mm.

The stability system 10 may further comprise an indicator 104 which is configured such that when the actuator unit 200 and vehicle mount 100 are assembled as herein described, the head end 402 of the support leg 400 and the free end 504 of the foot unit 500 are spaced apart by at least the first distance dl the indicator 104 indicates the actuator unit 200 is in the unloaded configuration Cl (as shown in Fig. 7A). This is because, in this configuration there is no force/load acting on the free end 504, and hence no force transmitted to the housing 300 to move/lift the housing relative vehicle mount 100 in a direction along the longitudinal axis 202.

The indicator 104 is further configured such that when the free end 504 of the foot unit 500 and head end 402 of the support leg 400 are spaced apart by less than the first distance dl the indicator 104 indicates the actuator unit 200 is in the loaded configuration C2 (as shown in Figs. 7B,C). This is because, in this configuration, there is a load acting on the free end 504, and hence a force acting on the free end 504, and hence a is force transmitted to the housing 300 to move/lift the housing 300 relative vehicle mount 100 in a direction along the longitudinal axis 202.

The indicator 104 a sensor 102 operable to generate a signal which indicates the value of indicator distance ID1, ID2 measured between a reference point on the housing 600 and the vehicle mount 100. Hence, as shown in Figures 2 to 7, the sensor 102 may be mounted to the top side of the housing 600, for example on a flange or plate 120, and configured to indicate the difference in distance between the sensor 102 when the actuator unit is in the unloaded configuration Cl (as shown in Fig. 7A) and the loaded configuration C2 (as shown in Figs. 7B,C).

Hence for example in Fig. 2 the sensor 102 is mounted to the housing 600 and orientated and configured to monitor the distance between the sensor 102 and the vehicle mount 100. Thus in the unloaded configuration Cl in Fig. 2 there will be determined a first indicator distance 101. In Fig. 3, which the foot unit is light in contact with the substrate, or Fig. 4 in which the foot unit 500 is pressed onto the substrate such that the resilient biasing member 410 is compressed, the housing 602 is urged/forced to slide upwards relative to the vehicle mount 100, to increase the distance between the sensor 102 and the vehicle mount 100, there will be measured a second indicator distance ID2, which is greater than the first indicator distance ID1, thereby indicating the actuator unit is in the loaded configuration C2.

Hence the housing 300 may slide relative to the vehicle mount 100 in the direction along the longitudinal axis 202 by the difference between the first indicator distance 101 and second indicator distance 102, which may have a value in the range of 4mm to 10mm, 5mm to 9mm or 4mm to 8mm.

Since the actuator unit 200 is mounted with the housing 300 above the foot unit 500, when the foot unit 500 is spaced apart from the supporting substrate/ground, and/or when there is no load -12 -on the foot unit 500, the actuator unit 200 will come to rest in the mount 100 in the unloaded configuration Cl.

The system may further comprise a control unit 106 operable to control the actuator unit 200 to induce a force on the support leg 400 to thereby move it along the longitudinal axis 202 through the housing 300. The control unit 106 may be operable to control the actuator unit 200 to induce a force on the support leg 400 in a direction along the longitudinal axis 202, for example away from the vehicle mount 100.

The control unit 106 of the system 10 is operable to control the actuator unit 200 in response to the signal which indicates the value of indicator distance 101 to increase the force on the support leg 400 (and/or urge the support leg 400 along the longitudinal axis 202) if the signal changes from indicating loaded configuration C2 to unloaded configuration Cl.

Operation of the stability system of the present disclosure will be described with reference to the arrangement shown in Fig. 1. In use, a stability system 10 configured as herein described may be operated in conjunction with other systems on a vehicle 20. For example, the stability system 10 may feed information to, and receive information from a control unit 106. In particular, the indicator 104 of the stability system may generate a signal to indicate the unloaded configurations Cl or loaded configuration C2 of the support leg. In other examples, the indicator 104 may additionally or alternatively be a visible indicator or audible alarm.

In an example manoeuvre, the lifting equipment 12 moves a load from position 1 P1 at the rear of the vehicle, in an arc around to position 2 P2 over one side of the vehicle, and then on to position 3 P3 towards the front of, and overhanging, the vehicle. During this manoeuvre the load on the support legs 400 of each actuator unit 200 Al, A5, A6 will be increased relative to the support legs 400 of each actuator unit 200 A2, A3, A4.

With reference to the actuator units 200 Al, A2 at one end of the vehicle (for example the front) as shown in Fig. 2, when not in use each actuator unit is stored in a retracted configuration such that the foot unit 500 is spaced apart from the substrate/ground on which the wheels 34 vehicle 20 stands. Hence, when not in use, each actuator unit 200 is stored in an unloaded configuration Cl with the distance between the head end 402 of the support leg 400 and the free end 504 of the foot unit 500 being at most the first distance di. The distance between the head end 402 of the support leg 400 and the free end 504 of the foot unit 500 is maintained by the resilient biasing member 410 acting between the support leg 400 and the foot unit 500.

Since the actuator unit 200 is mounted with the housing 300 above the foot unit 500, with the foot unit 500 spaced apart from the supporting substrate/ground, in the stored/retracted configuration shown in Fig. 2(01 Fig. 7A) the actuator unit 200 will sit on the vehicle mount 100 in the unloaded configuration Cl.

When being deployed, for example shown in Fig. 3 (or Fig. 78), the support leg 400 of each actuator unit 200 is extended towards the substrate. The actuator unit 200 induces a force on its respective support leg 400 to make it extend towards the substrate. For example, in an example where the actuator unit is a hydraulic unit, hydraulic fluid is pumped into a space between the housing 300 and the head end 402 of the support leg, thereby inducing force on the support leg 400 to make/urge it extend towards the substrate along the longitudinal axis.

Until the foot unit 500 makes contact with the substrate, the distance between the head end 402 of the support leg 400 and the free end 504 of the foot unit 500 is the first distance dl. When the foot unit 500 makes contact with the substrate the resilient biasing member 410 begins to compress, such that the distance between the head end 402 of the support leg 400 and the free end 504 of the foot unit 500 reduces. This also generates a reaction force which urges the housing 300 to slide relative to the vehicle mount 100 increasing the indicator distance ID, and placing the actuator unit 200 into a loaded configuration C2.

As shown in Fig. 4, with the system still in the loaded configuration C2 the actuator unit 200 further induces a force on its respective support leg 400, to compress the resilient biasing member 410 further, so the support leg slides along the foot unit cavity 510 until it reaches the foot unit end wall 540. The actuator unit may further drive the foot unit into contact with the substrate and to start to lift the vehicle mount (i.e. taking the load of the vehicle wheels to a desired extent).

Hence the force applied by the actuator unit Al, A2 in Fig. 4 (Fig. 7C) is greater than in Fig. 3 (Fig. 7B). Although both are a "loaded configuration", the state in Fig.3 (Fig. 7B) (where only a light force is applied by the actuator) may be termed a first loaded configuration C2-1, and in Fig.4 (Fig. 7C) (where a greater force is applied by the actuator) may be termed a second loaded configuration C2-2, Hence in as shown in Fig. 3, where the foot unit 500 pressed by the support leg 400 via the resilient biasing member 410, and as shown Fig. 4 where the where the foot unit 500 pressed directly by the support leg 400, the system is in the loaded configuration C2.

In Figs. 2 to 4 the vehicle is shown perpendicular to the substrate on which it stands. Hence, Figs. 2 to 4 illustrate the orientation that the vehicle may have when the lifting equipment 12 is in position 1 P1 shown in Fig. 1.

Fig. 5 illustrates the orientation that the vehicle may take up with lifting equipment is in position 3 P3, as shown in Fig. 1. In this example, the vehicle has tilted over to one side. In this arrangement, the distance between the head end 402 of the support leg 400 and the free end 504 of the foot unit 500 is different for each actuator unit 200 Al, A2. Hence for actuator unit A2 the distance is less than the first distance dl, but greater than the second distance d2. For actuator Al, the distance is the second distance d2. However, since there is load on the foot unit 500 for both, the actuators are both in the loaded configuration C2, indicated by a second distance ID2 between sensor 102 and the vehicle mount 100. Actuator A2 may be in the first loaded configuration C2-1 and Actuator Al may be in the second loaded configuration C2-2.

If the distance between the head end 402 of the support leg 400 and the free end 504 of the foot unit 500 was not variable, then actuator A2 would be in an unloaded configuration Cl, since the foot would have lifted clear of the substrate, thereby triggering an alarm or safety measure.

Fig. 6 illustrates the orientation that the vehicle may take up with lifting equipment is in position 2 P2, as shown in Fig. 1. In this example, the vehicle has tilted further over to one side than shown in Fig. 5. In this arrangement, the distance between the head end 402 of the support leg 400 and the free end 504 of the foot unit 500 is different for each actuator unit 200 Al, A2. For actuator A2 the foot unit 500 has lifted clear of the ground, and hence is in an unloaded configuration Cl indicated by a first distance ID1 between sensor 102 and the vehicle mount 100. Hence for actuator unit A2 the support assembly 700 is now fully extended to the first distance di. For actuator Al, the distance is the second distance d2. Since there is load on the foot unit 500 for actuator Al, this is in the loaded configuration C2, indicated by a second distance ID2 between sensor 102 and the vehicle mount 100. Since actuator A2 is in an unloaded configuration Cl, an alarm or safety measure may be triggered, interrupting the operation of the lifting apparatus until actuator A2 has been actuated to bring the foot unit 500 back into contact with the substrate.

-15 -Hence when, as shown in Fig. 7A, the head end 402 of the support leg 400 and the free end 504 of the foot unit 500 are spaced apart by at least the first distance dl the indicator 104 indicates the actuator unit 200 is in the unloaded configuration Cl. That is to say, when the head end 402 of the support leg 400 and the free end 504 of the foot unit 500 are spaced apart by the first distance di or more, the indicator 104 indicates the actuator unit 200 is in the unloaded configuration Cl. This is because, in this configuration there is no force/load acting on the free end 504, and hence no force transmitted to the housing 300 to move/lift the housing 300 relative vehicle mount 100.

Wien, as shown in Figs. 7B, 7C, the free end 504 of the foot unit 500 and head end 402 of the support leg 400 are spaced apart by less than the first distance dl the indicator 104 indicates the actuator unit 200 is in the loaded configuration C2. This is because, in this configuration, there is a force acting on the free end 504, and hence a force transmitted to the housing 300 to move/lift the housing 300 relative vehicle mount 100.

In examples where it is present, the sensor 102 generates a signal which indicates the value of indicator distance ID1 measured between a reference point on the housing 600 and the vehicle mount 100. In some examples, in response to receiving the signal which indicates the value of indicator distance ID1, and if the signal changes from indicating loaded configuration C2 to unloaded configuration Cl, the control unit 106 controls the actuator unit 200 to increase the force on the support leg 400 (and/or urge the support leg 400 along the longitudinal axis 202) until the sensor 102 generates a signal which indicates the housing 300 and vehicle mount 100 are in the loaded configuration C2.

Hence in the example of Fig. 6, the control unit 106 may control the actuator unit 200 to increase the force on the actuator A2 support leg 400 (and/or urge the support leg 400 along the longitudinal axis 202) until the sensor 102 generates a signal which indicates the housing 300 and vehicle mount 100 are in the loaded configuration C2.

Additionally, or alternatively, in the example of Fig. 6, the control unit 106 may detect that the force/load on the actuator A2 support leg 400 has dropped, and control the actuator unit to increase the force on the actuator A2 support leg 400.

-16 -Hence in use, up to a limit predefined limit, if the vehicle tips and lifts one of the support legs 400 relative to the ground then the foot stays in contact with the ground since the spring acts to keep the force on the support leg 400 so the indicator distance is maintained at a value which indicates a loaded configuration.

In an apparatus in which the operation of the lifting equipment and stability system are integrated, operation of lifting equipment will only be interrupted when the foot unit 500 and support leg 400 have reached a predetermined extension distance (and/or a predetermined minimum load) and hence avoids interruption of the operation of the lifting equipment in scenarios in which conventional systems would falsely indicate a risk of instability. Hence the arrangement of the present disclosure acts to prevent small relative motions between the support leg relative to the ground from halting the operation of the associated lifting equipment under conditions where the relative motions are too small to jeopardise operational safety of the apparatus.

Having a support assembly 700 comprising a foot unit 500 which is slidable relative to the support leg 400 to which it is attached, with the resilient biasing member 410 (or the like) between the foot unit 500 and the support leg 400, ensures that up to a maximum predetermined extent, the foot unit 500 remains in contact with the ground/substrate, and hence ensures the actuator unit 200 is in a loaded configuration Cl during a transition period when load is reduced on the support assembly 700. For systems as herein described, this will ensure a reduction of indications of instability which are false alarms.

Hence a stability system comprising an actuator unit 200 of the present disclosure, when used as part of a stability system for a vehicle, will increase the operational flexibility of load moving equipment fitted to the vehicle since the load moving equipment will be able to operate over a wider range of manoeuvres than with a stability system comprising an actuator unit of the related art.

Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

-17 -All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

-18 -CLAIMS1 A stability system (10) for a vehicle (20) comprising: an actuator unit (200) centred on a longitudinal axis (202); the actuator unit (200) having a housing (300), a support leg (400) and a foot unit (500); the support leg (400) having a head end (402) and a foot end (404); the head end (402) located within the housing (300) with the support leg (400) extending from the head end (402) to the foot end (404), and the foot end (404) extends out of an opening (310) in the housing (300), the support leg (400) and housing (300) being slideable relative to each other along the longitudinal axis (202); the foot unit (500) having a coupling portion (502) coupled to the foot end (404) of the support leg (400) and a free end (504) distal to the coupling portion (502); the foot unit (500) and support leg (400) being moveable relative to one another along the longitudinal axis (202) such that the distance between the head end (402) of the support leg (400) and the free end (504) of the foot unit (500) is at most a first distance (d1) and no less than a second distance (d2), the second distance being smaller than the first distance.
2 A stability system (10) as claimed in claim 1 wherein the first distance (d1) is the fully extended length of the foot unit (500) and support leg (400) assembly, and the second distance (d2) is the minimum length of the foot unit (500) and support leg (400) assembly.
3 A stability system (10) as claimed in any one of claims 1, 2 wherein the housing (300) defines a hollow chamber (320); the support leg (400) defines a hollow chamber (422) the support leg (400) being closed at the head end (402) and defining an aperture (420) at the foot end (404) which receives the coupling portion (502) of the foot unit (500).
-19 - 4 A stability system (10) as claimed in claim 3 wherein the free end of the foot unit (500) comprises a base portion (520), which extends to the coupling portion (502), the coupling portion comprising an end wall (540), an outer wall (506) and a spigot (508), the outer wall (506) and spigot (508) extending from the end wall (540), and the outer wall (506) bounds, and is spaced apart from, the spigot (508) to define an annular cavity (510) which extends around the spigot (508); wherein the spigot (508) and support leg aperture (420) are configured so that the spigot (508) fits through the support leg aperture (420) to enter the support leg hollow chamber (422); and the foot unit cavity (510) is configured to receive the support leg (400), and to allow the support leg to slide along the cavity (510) until it reaches the end wall (540); such that when the foot end (404) of the support leg is engaged with the end wall (540), the head end (402) of the support leg (400) and the free end (504) of the foot unit (500) are spaced apart by the second distance (d2).
A stability system (10) as claimed in claim 4 wherein the coupling portion (502) outer wall (506) defines a slot (526) extending from a first stop end (528) furthest from the free end (504) to second stop end (530) closest to the free end (504); and a guide pin (512) extends from the support leg (400) through the slot (526); such that when the guide pin (512) is engaged with the first stop end (528), the head end (402) of the support leg (400) and the free end (504) of the foot unit (500) are spaced apart by the first distance (c11).
6 A stability system (10) as claimed in any one of the preceding claims further comprising: a vehicle mount (100); the housing (300) is carried by the vehicle mount (100) such that the actuator unit (200) and vehicle mount (100) have an unloaded configuration (Cl) and a loaded configuration (C2).
7 A stability system (10) as claimed in claim 6 wherein the housing (300) is carried by the vehicle mount (100) so that it is limited to be slideable relative to the vehicle mount (100) between a first position and a second position along the longitudinal axis (202) between the unloaded configuration (Cl) and the loaded configuration (C2) respectively. -20 -
8 A stability system (10) as claimed in claim 7, further comprising an indicator (104) which is configured such that: when the head end (402) of the support leg (400) and the free end (504) of the foot unit (500) are spaced apart by at least the first distance (dl), the indicator (104) indicates the actuator unit (200) is in the unloaded configuration (Cl); and when the free end (504) of the foot unit (500) and head end (402) of the support leg (400) are spaced apart by less than the first distance (d1) the indicator (104) indicates the actuator unit (200) is in the loaded configuration (C2).
9 A stability system (10) as claimed in claim 7 or claim 8, wherein the system further comprises a sensor (102) operable to generate a signal which indicates the value of indicator distance (ID1, ID2) measured between a reference point on the housing (600) and the vehicle mount (100), and hence indicates if the housing (300) is the unloaded configuration (Cl) or the loaded configuration (C2).
10. A stability system (10) as claimed in any one of the preceding claims wherein the system further comprises a control unit (106) operable to control the actuator unit (200) induce a force on the support leg (400).
11. A stability system (10) as claimed in claim 10 when dependent on claim 9 wherein the control unit (106) is operable to control the actuator unit (200) in response to the signal which indicates the value of indicator distance (ID1) to increase the force on the support leg (400) if the signal changes from indicating loaded configuration (C2) to unloaded configuration (Cl).
12. A stability system (10) as claimed in any one of the preceding claims further comprising: a resilient biasing member (410) housed within the support leg (400) and extending along the inside of the support leg (400); the resilient biasing member (410) provided between the foot unit (500) and the support leg (400). -21 -
13. A stability system (10) as claimed claim 12 wherein the support leg (400) comprises a support base (430) which extends along the inside of the support leg (400) to co-operate with one end of the resilient biasing member (410); and the other end of the resilient biasing member (410) co-operates with a face of the foot unit spigot (508) which faces the head end of the support leg (400).
14. A stability system (10) as claimed in any one of claims 1 to 10 wherein the support leg (400), resilient biasing member (410) and foot unit (500) are co-axial and/or concentric and centred on the longitudinal axis (208).
15. A vehicle comprising a stability system (10) as claimed in any one of claims 1 to 14.
16. A method of operation a stability system (10) for a vehicle (20), the stability system (10) comprising: an actuator unit (200) centred on a longitudinal axis (202); the actuator unit (200) having a housing (300), a support leg (400) and a foot unit (500); the support leg (400) having a head end (402) and a foot end (404); the head end (402) located within the housing (300) with the support leg (400) extending from the head end (402) to a foot end (404), and the foot end (404) extends out of an opening (310) in the housing (300), the support leg (400) and housing (300) being slideable relative to each other along the longitudinal axis (202); the foot unit (500) having a coupling portion (502) coupled to the foot end (404) of the support leg (400) and a free end (504) distal to the coupling portion (502); the foot unit (500) and support leg (400) being moveable relative to one another along the longitudinal axis (202) such that the distance between the head end (402) of the support leg (400) and the free end (504) of the foot unit (500) is at most a first distance (d1) and no less than a second distance (d2), the second distance being smaller than the first distance; and an indicator (104); the method compromising the steps of: when the head end (402) of the support leg (400) and the free end (504) of the foot unit (500) are spaced apart by at least a first distance (dl), the indicator (104) indicates the actuator unit (200) is in the unloaded configuration (Cl); and -22 -when the free end (504) of the foot unit (500) and head end (402) of the support leg (400) are spaced apart by less than the first distance (d1) the indicator (104) indicates the actuator unit (200) is in the loaded configuration (C2).
17. A method as claimed in claim 16, wherein the system further comprises a vehicle mount (100); wherein the housing (300) is carried by the vehicle mount (100) so that it is limited to be slideable relative to the vehicle mount (100) by an indicator distance (ID1) along the longitudinal axis (202) between the unloaded configuration (Cl) and the loaded configuration (C2) , and a sensor (102) and the method comprises the step of: the sensor (102) generating a signal which indicates the value of indicator distance (ID1) measured between a reference point on the housing (600) and the vehicle mount (100).
18. A method as claimed in claim 17 wherein the method further comprises the steps of in response to the signal which indicates the value of indicator distance (ID1), and if the signal changes from indicating loaded configuration (C2) to unloaded configuration (Cl), the control unit (106) controls the actuator unit (200) to increase the force on the support leg (400) until the sensor (102) generates a signal which indicates the housing (300) and vehicle mount (100) are in the loaded configuration (C2).Amendments to the claims have been filed as ollows.CLAIMS1 A stability system (10) for a vehicle (20) comprising: an actuator unit (200) centred on a longitudinal axis (202); the actuator unit (200) having a housing (300), a support leg (400), a resilient biasing member (410), and a foot unit (500); the support leg (400) having a head end (402) and a foot end (404); the head end (402) located within the housing (300) with the support leg (400) extending from the head end (402) to the foot end (404), and the foot end (404) extends out of an opening (310) in the housing (300), the support leg (400) and housing (300) being slideable relative to each other along the longitudinal axis (202); the resilient biasing member (410) housed within the support leg (400) and extending C\J along the inside of the support leg (400); C\I 15 the resilient biasing member (410) provided between the foot unit (500) and the support leg (400); CD the foot unit (500) having a coupling portion (502) coupled to the foot end (404) of the 4171- support leg (400) and a free end (504) distal to the coupling portion (502); the foot unit (500) and support leg (400) being moveable relative to one another along the longitudinal axis (202) such that the distance between the head end (402) of the support leg (400) and the free end (504) of the foot unit (500) is at most a first distance (d1) and no less than a second distance (d2), the second distance being smaller than the first distance.2 A stability system (10) as claimed in claim 1 wherein the first distance (d1) is the fully extended length of the foot unit (500) and support leg (400) assembly; and the second distance (d2) is the minimum length of the foot unit (500) and support leg (400) assembly.3. A stability system (10) as claimed in any one of claims 1, 2 wherein the housing (300) defines a hollow chamber (320); the support leg (400) defines a hollow chamber (422), the support leg (400) being closed at the head end (402) and defining an aperture (420) at the foot end (404) which receives the coupling portion (502) of the foot unit (500).4 A stability system (10) as claimed in claim 3 wherein the free end of the foot unit (500) comprises a base portion (520), which extends to the coupling portion (502); the coupling portion comprising an end wall (540), an outer wall (506) and a spigot (508), the outer wall (506) and spigot (508) extending from the end wall (540), and the outer wall (506) bounds, and is spaced apart from, the spigot (508) to define an annular cavity (510) which extends around the spigot (508); wherein the spigot (508) and support leg aperture (420) are configured so that the spigot (508) fits through the support leg aperture (420) to enter the support leg hollow chamber (422); and C\J 15 the foot unit cavity (510) is configured to receive the support leg (400), and to allow the C\I support leg to slide along the cavity (510) until it reaches the end wall (540); such that when the foot end (404) of the support leg is engaged with the end wall (540), the head end (402) of the support leg (400) and the free end (504) of the foot unit (500) 4171- are spaced apart by the second distance (d2).A stability system (10) as claimed in claim 4 wherein the coupling portion (502) outer wall (506) defines a slot (526) extending from a first stop end (528) furthest from the free end (504) to second stop end (530) closest to the free end (504); and a guide pin (512) extends from the support leg (400) through the slot (526); such that when the guide pin (512) is engaged with the first stop end (528), the head end (402) of the support leg (400) and the free end (504) of the foot unit (500) are spaced apart by the first distance (d1).6 A stability system (10) as claimed in any one of the preceding claims further comprising: a vehicle mount (100); the housing (300) is carried by the vehicle mount (100) such that the actuator unit (200) and vehicle mount (100) have an unloaded configuration (Cl) and a loaded configuration (C2).7 A stability system (10) as claimed in claim 6 wherein the housing (300) is carried by the vehicle mount (100) so that it is limited to be slideable relative to the vehicle mount (100) between a first position and a second position along the longitudinal axis (202) between the unloaded configuration (Cl) and the loaded configuration (C2) respectively.8 A stability system (10) as claimed in claim 7, further comprising an indicator (104) which is configured such that: when the head end (402) of the support leg (400) and the free end (504) of the foot unit (500) are spaced apart by at least the first distance (d1), the indicator (104) indicates the actuator unit (200) is in the unloaded configuration (Cl); and when the free end (504) of the foot unit (500) and head end (402) of the support leg (400) are spaced apart by less than the first distance (d1) the indicator (104) indicates the actuator unit (200) is in the loaded configuration (C2). C\JC\I 15 9 A stability system (10) as claimed in claim 7 or claim 8, wherein the system further comprises a sensor (102) operable to generate a signal which indicates the value of o indicator distance (ID1, ID2) measured between a reference point on the housing (600) and the vehicle mount (100), and hence indicates if the housing (300) is the unloaded 171- configuration (Cl) or the loaded configuration (C2).CD10. A stability system (10) as claimed in any one of the preceding claims wherein the system further comprises a control unit (106) operable to control the actuator unit (200) induce a force on the support leg (400).11. A stability system (10) as claimed in claim 10 when dependent on claim 9 wherein the control unit (106) is operable to control the actuator unit (200) in response to the signal which indicates the value of indicator distance (ID1) to increase the force on the support leg (400) if the signal changes from indicating loaded configuration (C2) to unloaded configuration (Cl).12. A stability system (10) as claimed claim 1 wherein the support leg (400) comprises a support base (430) which extends along the inside of the support leg (400) to co-operate with one end of the resilient biasing member (410); and the other end of the resilient biasing member (410) co-operates with a face of the foot unit spigot (508) which faces the head end of the support leg (400).13. A stability system (10) as claimed in any one of claims 1 to 10 wherein the support leg (400), resilient biasing member (410) and foot unit (500) are co-axial and/or concentric and centred on the longitudinal axis (208).14. A vehicle comprising a stability system (10) as claimed in any one of claims 1 to 13.15. A method of operation for a stability system (10) as claimed in claim 1, the method compromising the steps of: when the head end (402) of the support leg (400) and the free end (504) of the foot unit (500) are spaced apart by at least a first distance (dl), an indicator (104) indicates the actuator unit (200) is in the unloaded configuration (Cl); and when the free end (504) of the foot unit (500) and head end (402) of the support leg (400) C\J are spaced apart by less than the first distance (d1) the indicator (104) indicates the C\I 15 actuator unit (200) is in the loaded configuration (C2). C\I16. A method as claimed in claim 15, wherein the system further comprises a vehicle mount o '171- (100); wherein the housing (300) is carried by the vehicle mount (100) so that it is limited to be slideable relative to the vehicle mount (100) by an indicator distance (ID1) along the longitudinal axis (202) between the unloaded configuration (Cl) and the loaded configuration (C2) , and a sensor (102); and the method comprises the step of: the sensor (102) generating a signal which indicates the value of indicator distance (I01) measured between a reference point on the housing (600) and the vehicle mount (100).17. A method as claimed in claim 16 wherein the method further comprises the steps of in response to the signal which indicates the value of indicator distance (ID1), and if the signal changes from indicating loaded configuration (C2) to unloaded configuration (Cl), the control unit (106) controls the actuator unit (200) to increase the force on the support leg (400) until the sensor (102) generates a signal which indicates the housing (300) and vehicle mount (100) are in the loaded configuration (C2).