WO2002049954A1

WO2002049954A1 - An improved stabiliser leg

Info

Publication number: WO2002049954A1
Application number: PCT/NZ2001/000289
Authority: WO
Inventors: Peter Andrew Suckling; Alan Gary Swarbrick
Original assignee: Steelbro New Zealand Limited
Priority date: 2000-12-19
Filing date: 2001-12-19
Publication date: 2002-06-27
Also published as: MY128542A; SE0301765D0; AU1650202A; AU2002216502B2; SE524169C2; SE0301765L

Abstract

A stabiliser leg including a housing pivotally mounted on a vehicle with an extension member telescopically mounted upon the housing, a first hydraulic cylinder for controlling the angle of the housing relative to the vehicle, and a second hydraulic cylinder for controlling the extension of the extension member; an ankle pivotally secured to the lower end of the extension member, such that the ankle can be pivoted between a storage position in which its longitudinal axis is substantially perpendicular to that of the extension member, and an in use position in which its longitudinal axis is aligned with that of the extension member; also including means for locking the ankle in the in use position without the use of a third hydraulic cylinder, and a ground engaging foot which is pivotally secured to the lower end of the ankle.

Description

An Improved Stabiliser Leg

Technical Field

The present invention relates to an improved retractable stabiliser leg for vehicle mounted loading apparatus such as cranes.

Background Art

Stabiliser legs are well-known and are used to prevent tipping of a vehicle during the transfer of a load to or from the vehicle flatbed or the deck of a trailer. Increasing the length of a stabiliser leg increases the stability of the loading apparatus, but since each stabiliser leg normally is stored across the width of the vehicle when not in use, the restrictions on overall vehicle width (2.5 m in a majority of countries) limit the length of the stabiliser leg. To overcome this problem, it is known to manufacture a stabiliser leg in two sections:- a housing and an extension member; the extension member telescopes over the housing. A foot is mounted on the free end of the extension member for contact with the ground. The angle of the stabiliser leg relative to the vehicle is controlled by a first hydraulic cylinder, and the extension of the extension member relative to the housing is controlled by a second hydraulic cylinder.

To extend the overall length of the stabiliser leg further without increasing the stored length of the stabiliser leg, it is necessary to add a further section to the stabiliser leg between the foot and the corresponding end of the extension member. This further section can be designed to telescope within the extension member/housing and its extension relative to the extension member and housing controlled by a third hydraulic cylinder. However, this design has a number of drawbacks:- the use of a third hydraulic cylinder increases the weight and the manufacturing cost of the stabiliser leg, and also increases the time needed to manufacture the stabiliser leg.

Disclosure of Invention

An object of the present invention is the provision of a stabiliser leg which has a greater maximum length in use, but which does not exceed the acceptable maximum length in the storage position, and which requires only two hydraulic cylinders for complete control of both angle and length. The present invention provides a stabiliser leg which includes: a housing pivotally mountable upon a vehicle; an extension member telescopically mounted upon the housing; a first hydraulic cylinder for controlling the angle of the housing relative to the vehicle; a second hydraulic cylinder for controlling the extension of the extension member relative to the housing; characterised in that the stabiliser leg further includes: an ankle pivotally secured to the extension member, at or adjacent that end of the extension member which is lowermost when the stabiliser leg is in use; said ankle being pivotable relative to the extension member, between a storage position in which the longitudinal axis of the ankle is substantially perpendicular to the longitudinal axis of the extension member, and an in use position in which the longitudinal axes of the ankle and the extension member are aligned; means for locking said ankle in the in use position without using a third hydraulic cylinder; and a ground engaging foot pivotally secured to the end of the ankle remote from the extension member.

As used herein, the term "substantially perpendicular" means at an angle of 90 Degrees plus or minus 20 Degrees.

Description of the Drawings.

By way of example only, preferred embodiments of the present invention are described in detail with reference to the accompanying drawings in which:-

Figures 1-5 are diagrammatic side views (partial in the case of Figure 4) of a stabiliser leg in accordance with a first embodiment of the present invention, showing the sequence of moving the stabiliser leg from the stored position of Figure 1 to the in use position of Figure 5;

Figure 6 is a partial view similar to that of Figure 5, but showing the stabiliser leg with an enlarged ground engaging portion;

Figure 7 is a diagrammatic side view of part of a stabiliser leg in accordance with a second embodiment of the present invention; and

Figure 8 is an enlarged view of part of Figure 7. Detailed Description of Preferred Embodiments

Referring initially to Figures 1-5 of the drawings, in a first embodiment of the present invention a stabiliser leg 2 is mounted across the width of a vehicle by means of two spaced pivotal mountings to the deck 3 of the vehicle:- the first pivotal mounting 4 secures one end of a first hydraulic cylinder 5 to the deck 3; and a second pivotal mounting 6 secures the stabiliser leg housing 7 to the deck 3.

The housing 7 comprises a reinforcing collar 8 which encircles and supports an elongated housing portion 9, which forms the upper part of the stabiliser leg in use. A second hydraulic cylinder 10 is mounted within the elongated housing portion 9, which is constructed as a box section. The top of the hydraulic cylinder 10 is pivotally secured to a mounting flange located at the inner top of the elongated housing portion 9, and the base of the hydraulic cylinder 10 is supported within the part of the elongated housing portion 9 surrounded by the collar 8. The end of the ram 11 of the hydraulic cylinder 10 is pivotally secured to a mounting point 12 at the end of an extension member 13.

The extension member 13 is formed as a box section and is proportioned such that in the stored position shown in Figure 1 , the extension member 13 telescopes over the elongated housing portion 9, thus folding the stabiliser leg to an acceptable length for storage across the width of the vehicle.

The above described arrangement is known, and therefore is not described in detail. In use, when it is necessary to extend the stabiliser leg the hydraulic cylinder 10 is operated to extend the extension member 13 relative to the housing 7, and the hydraulic cylinder 5 is operated to alter the angle of the extended stabiliser leg as necessary:- extension of the hydraulic cylinder 5 pivots the stabiliser leg on the pivot 6.

In the present invention, instead of the lower end of the extension member 13 being connected to a ground engaging foot, the lower end of the extension member 13 has an ankle 14 secured to it at a pivot axis coincident with the pivot axis 12. The ankle 14 is secured to the member 13 at or close to the midpoint of the length of the ankle.

The ankle 14 is formed as an elongated member, preferably of box section, with a flat plate 15 rigidly secured across the upper portion of the outer face of the ankle. The plate 15 extends beyond the upper edge of the elongated member to provide a flange 15a which lies in a plane parallel to the longitudinal axis of the ankle. A ground engaging foot 16 of known type is pivotally secured to the end of the ankle remote from the extension member 13 at a pivot 17, in known manner.

A coil spring 18 is secured in tension between the adjacent ends of the extension member 13 and the ankle 14.

The sequence of extending the stabiliser leg 2 is shown in Figures 1-5. The vehicle is positioned in an appropriate place relative to the load to be lifted onto the vehicle, and then each stabiliser leg is extended:- first, the second hydraulic cylinder 10 is operated to extend the extension member 13 relative to the housing 7:- as the ram 11 of the hydraulic cylinder 10 is advanced, the extension member 13 is extended as shown in Figures 1-4.

In the stored position shown in Figure 1, both the foot 16 and the ankle 14 are stowed with the respective plates 16,15 flat against the end of the collar 8, with the planes of the plates substantially vertical and the spring 18 in tension. The foot 16 and ankle 14 are held in this position by the force of the hydraulic cylinder 10 holding the extension member 13 in the retracted position. As the extension member 13 is moved away from the collar 8 by the extension of the ram 11, the force of the spring 18, which is secured to the ankle 14 at a position vertically higher than the pivotal connection 12 between the ankle 14 and the extension member 13, pivots the ankle 14 relative to the extension member 13. Thus, as the extension member 13 moves away from the housing as shown in Figures 2 and 3, the ankle 14 gradually pivots anticlockwise about the pivot 12 until the flange 15a of the plate 15 contacts the outer face of the extension member 13, as shown in Figure 4.

In this position, the length of the ankle 14 is aligned with the length of the extension member 13, so that the ankle 14 effectively extends the extension member 13. The hydraulic cylinder 5 is then operated to pivot the stabiliser leg 2 about the pivot mounting 6, to adjust the angle of the stabiliser leg to the required position, with the base of the foot 16 flat on the ground. In this position, the flange 15a is pressed tightly into contact with the extension member 13, preventing movement of the ankle 14 relative to the extension member 13. The foot 16 has a limited range of pivotal movement relative to the ankle 14, in known manner, so that the foot 16 can adjust to uneven ground surfaces.

When the stabiliser leg 2 is to be retracted back to the stowed position of Figure 1 , the hydraulic cylinder 5 is operated to lift the foot 16 out of ground contact, until the stabiliser leg reaches approximately the position shown in Figure 4 i.e., with the stabiliser leg substantially horizontal. The second hydraulic cylinder 10 is then operated to retract the ram 11 and telescope the extension member 13 over the elongated housing portion 9. As the ram 11 is retracted, the flange 15a bears on the end 8 a of the housing, causing the ankle 14 to rotate clockwise about the pivot 12, until the longitudinal axis of the ankle 14 is substantially vertical as shown in Figure 1. The base plate of the foot 16 also bears against the outer edge 8b of the collar 8, rotating the foot anticlockwise from the position shown in figure 3 to the position shown in Figure 1.

Figure 6 shows a variant of the load supporting position of Figure 5, where a shorter length of stabiliser leg is acceptable but a greater area of ground engaging contact is required. In the position shown in Figure 6, the entire ankle 14 is manually rotated clockwise until the whole of the plate 15 is coplanar with the base plate of the foot 16, and the stabiliser leg rests on both the plates 15 and 16.

It will be appreciated that the spring 18 is optional:- the spring 18 facilitates the rotation of the ankle 14 in the correct manner when the stabiliser leg moves from the stowed to the in use position, but if the spring 18 is omitted, the ankle 14 may be simply rotated manually as the ram 11 is extended.

Figures 7 and 8 show a second embodiment of the present invention. This embodiment differs from the first only in the manner of attachment of the ankle 20 to the extension member 13; identical or substantially identical components are given the same reference here as in Figures 1-6.

In the second embodiment, instead of being secured to the extension member 13 at the pivot 12 which is the anchorage for the end of the ram 11 , the ankle 20 is secured to the end of the extension member 13 by a pivot 21 at the lower corner of the extension member 13. The pivot 21 is located off centre of the length of the ankle 20, close to one end of the ankle 20. The ankle 20 is formed as an elongated member, preferably of box section, in the same general manner as ankle 14, but the plate 15 is not present and the upper edge 22 of the ankle 20, at the end of the ankle nearest to the extension member 13, is curved. In addition, a cutout 23 is formed at the lower end of the curve 22.

In the stowed position, the ankle 20 is arranged with its longitudinal axis substantially vertical, and the foot 16 pivots around to a substantially vertical position also. In this position, the contraction of the ram 11 holds the edge 24 of the ankle 20 tightly against the end of the collar 8, and prevents the ankle from rotating. This gives a stable storage position.

When the stabiliser leg 2 is to be moved to the in use position, the ram 11 is extended, which moves the ankle 20 away from the housing 8 and allows it to swing clockwise about the pivot 21 under its own weight. Figure 7 shows the ankle 20 as it starts to rotate towards the in use position. The ankle 20 continues to rotate until it reaches a position where its longitudinal axis is substantially aligned with the longitudinal axis of the extension member 13, and is prevented from pivoting past was position by a stop (not shown) formed on the interior surface of the extension member 13. The surface 25 of the extension member 13 is cut away adjacent the pivot 21 to allow the curved end 22 of the ankle 20 to lie between the sides of the extension member 13, and the ankle 20 is retained in this position by a latch 26 which is located inside the extension member 13 adjacent the cut away.

As shown on an enlarged scale in Figure 8, the latch 26 comprises a top plate 30 which acts as a retainer and guide for a sliding block 31 which is arranged to slide on the lower surface 25 of the extension member 13, in the direction of arrows A & B. The end of the block 31 furthest from the ankle 20 is secured to one end of a pair of pivoting rods 32,33; the free end of the rod 33 is pivoted to one end 34 of a bell crank 35 which is pivoted to the interior of the extension member 13 by a pivot 36.

The bell crank 35 is biased in the opposite direction to Arrow C by a tension spring 37 secured between strong points 38,39 on the bell crank 35 and top plate 30 respectively. The spring 37 biases the bell crank 35 to a position in which the lower end 40 of the bell crank protrudes below the lower surface 25 of the extension member 13 and the block 31 is urged in the direction of Arrow B.

As the ankle 20 pivots towards the in use position and the curved surface 22 of the ankle 20 swings into the cut away in the surface 25 of the extension member 13, the curved surface 22 bears against the end of the block 31 and pushes it clear of the cut away, to allow the ankle 20 to rotate. When the end of the curved portion 22 is reached, the block 31 snaps into the cutout 23 and locks the ankle in position relative to the extension member 13. This secures the ankle in the extended in use position.

When the stabiliser leg is to be moved from the in use to the stored position, the ram 11 is retracted, drawing the extension member 13 towards the collar 8. As the portion of the extension member 13 carrying the latch 26 approaches the collar, the protruding lower end 40 of the bell crank 35 contacts the edge 41 of the collar 8, rotating the bell crank in the direction of Arrow C and thus moving the block 31 in the direction of Arrow A. This releases the ankle 20, and further contraction of the ram 11 brings the curved surface 22 of the ankle 20 to bear against the end 41 of the collar 8, causing the ankle 20 to pivot towards the raised storage position.

It will be appreciated that the above described invention provides a useful extension of the length of the stabiliser leg which is inexpensive to manufacture and maintain and straightforward to use.

Although the stabiliser leg of the present invention has been described with particular reference to the vehicle mounted use, since vehicle mounted use involves particular maximum stowed length restrictions, the stabiliser leg of the present invention may of course be used in combination with non mobile loading apparatus.

Claims

1. A stabiliser leg which includes: a housing pivotally mountable upon a vehicle; an extension member telescopically mounted upon the housing; a first hydraulic cylinder for controlling the angle of the housing relative to the vehicle; a second hydraulic cylinder for controlling the extension of the extension member relative to the housing; characterised in that the stabiliser leg further includes: an ankle pivotally secured to the extension member, at or adjacent e of the extension member which is lowermost when the stabiliser leg is in use; said ankle being pivotable relative to the extension member, between a storage position in which the longitudinal axis of the ankle is substantially perpendicular to the longitudinal axis of the extension member, and an in use position in which the longitudinal axes of the ankle and the extension member are aligned; means for locking said ankle in the in use position without using a third hydraulic cylinder; and a ground engaging foot pivotally secured to the end of the ankle remote from the extension member.

2. The stabiliser leg as claimed in claim 1 , wherein the ankle is pivotally secured to the extension member at or about the midpoint of the length of the ankle, and said means for locking the ankle in the in use position comprises a plate secured to an external surface of the ankle, said plate being located and arranged such that when the extension member and the ankle are in the in use position, the plate bears against an external surface of the extension member so as to prevent anticlockwise rotation of the ankle relative to the extension member.

3. The stabiliser leg as claimed in claim 2, wherein the ankle is pivotally secured to the extension member at a pivot axis coincident with the pivotal securement of the ram of said second hydraulic cylinder to the extension member.

4. The stabiliser leg as claimed in claim 3, further comprising a spring secured in tension between the ankle and the corresponding end of the extension member, said spring being located and arranged relative to said pivot axis such that when the stabiliser leg initially is moved from the storage towards the in use position, the spring causes anticlockwise rotation of the ankle relative to the extension member.

5. The stabiliser leg as claimed in any one of claims 2 - 4, wherein said ankle is pivotable from the in use position to a secondary in use position in which said plate engages the ground substantially coplanar with said foot.

6. The stabiliser leg as claimed in claim 1 wherein the ankle is pivotally secured to the extension member adjacent one end of the ankle, and said means for locking the ankle in the in use position comprises a spring loaded catch mounted on the extension member and arranged to engage and lock the ankle in the in use position.

The stabiliser leg as claimed in claim 6 wherein the spring loaded catch comprises a sliding block spring biased towards the locking position, said block being dimensioned and arranged to engage a cutout formed on the corresponding end of the ankle when in said locking position.

!. The stabiliser leg as claimed in claim 7 wherein said spring loaded catch incorporates a lever arranged to engage the housing and release the catch as the stabiliser leg is moved towards the storage position.