Leaf spring stabiliser

Abstract: A vehicle spring stabiliser has a leaf spring with a connector pivotally secured to each end eye thereof, the connector in the form of a rigid yoke to embrace a vehicle spring assembly and having anti-friction means in the form of a sleeve on a spacer mounted on a bolt connecting the arms of the yoke.

Description: FIELD OF THE INVENTION This invention relates to a stabiliser for a leaf spring and more particularly for a leaf spring providing suspension for a road vehicle. BACKGROUND TO THE INVENTION Many road vehicles include the suspension for the rear axle in the form of a bowed leaf spring assembly between the chassis and each end of the rear axle. These springs are designed to support a predetermined range of weight and loading. Frequently this design support is exceeded by loading the vehicle directly or by the securing of a trailer of one form or another to the vehicle. Where such operating conditions are encountered it is known to include leaf spring stabilisers for each spring, Such stabilisers are known to include a further leaf spring blade mounted on top of the vehicle axle and having its ends connected to the leaf spring assembly. These stabilisers have mitigated damage to the suspensions when overloaded but have had limitations. Some utilise a flexible connection between the stabiliser and spring assembly. Under conditions causing severe flexing of the spring assembly the stabilising effect is lost and failure of the spring assembly can occur. Where the stabiliser is rigidly secured to the spring assembly the degree of flexing is limited and any movement beyond that limit can cause failure of the stabilising effect. OBJECT OF THE INVENTION It is an object of the present invention to provide a spring stabiliser assembly in which the above difficulties are overcome to an appreciable degree. US-A-2,492,416 and US-A-2,505,733 each disclose a leaf spring stabiliser unit in which a first stabilising leaf spring above the vehicle axle is connected to a second leaf spring beneath the vehicle axle by respective shackle assemblies at each end of the leaf springs. Each shackle assembly includes a central hollow spindle secured to a chassis support bracket, and a pair of shackles extending in opposing directions from the spindle to embrace the respective leaf springs. Each shackle includes a shackle pin that passes through the eye of the respective leaf spring. US-A-1,747,725 discloses a vehicle leaf spring unit consisting of at least three sections, the action of the main spring section being normally opposed by the auxiliary spring sections but the action of the auxiliary springs being successively reversed in compression to assist the action of the main spring as the main spring is progressively compressed. US-A-3,177,005 discloses a leaf spring hanger design in which one or both ends of the leaf spring nest inside a channel section frame member. A bushing extends through the eye of the spring and a spring hanger bolt extends through the bushing, the end of the bolt being secured in such a manner that the leaf spring is mounted without a conventional spring hanger bracket. According to the present invention there is provided a vehicle spring stabilizer unit comprising a leaf spring for mounting above the vehicle axle, a connector pivotally secured at each end of the leaf spring for connecting the leaf spring to a vehicle spring assembly below the vehicle axle, each connector including a pair of opposed members for embracing the vehicle spring assembly, characterised in that the said members are rigidly spaced apart by a spacer to permit relative translational movement between the members and the vehicle spring assembly when the leaf spring is flexed, the relative movement being accommodated by an anti-friction member disposed between the spacer and the vehicle spring assembly. Preferably the connector is in the form of a yoke engageable around the vehicle leaf spring assembly and the anti-friction member is a rotatable sleeve on the spacer disposed between the arms of the yoke. The arms of the yoke may be connected at one end by a first bolt carrying the spacer on which is mounted the rotatable sleeve, and at the other end by a second bolt extending through an eye of the leaf spring. In one alternative embodiment, the first bolt is stepped or provided with a self-locking nut to provide the spacer. These and other features of this invention will become apparent from the following description of one example of a spring stabiliser embodying the invention. In this description reference will be made to the accompanying drawings in which: Figure 1 shows the spring stabiliser in position is use; and Figure 2 shows a transverse cross section through one end of the stabiliser. As illustrated the spring stabiliser (1) is mounted above the vehicle axle (2) and consists of a leaf spring (3) and connectors (4) at each end of the spring (3). Each connector (4) consists of a pair of side arms (5) forming a yoke engaged around the vehicle leaf spring assembly (6). The upper ends of the arms (5) are connected together and pivotally secured to the eye (7) of the leaf spring (3) by a bolt (8) passed through the arms (5) and the eye of the leaf spring (3). A bush (9) is mounted on the bolt (8) to facilitate relative rotational movement between the bolt (8) and the eye (7) of the leaf spring (3). The lower ends of the arms (5) embrace the vehicle leaf spring assembly (6). The arms (5) are connected together by a bolt (10) on which is a spacer (11) which ensures that there can be. relative movement between the spring assembly (6) and the arms (5). A sleeve (12) is rotatably mounted on the spacer (11). With the spring stabiliser (1) mounted to the vehicle spring assembly (6) it will be appreciated that as the vehicle spring assembly (6) and leaf spring (3) flex under load during use there will be a small translational movement between the connectors (4) and the vehicle spring assembly (6). The small movement is sufficient to prevent damage to or failure of the stabiliser under severe conditions of use and is accommodated by rotation of sleeve (12) on the spacer (11) and against the vehicle spring assembly (6). The embodiment above described can be varied in many ways without departing from the scope of the invention, the essential of which is that the connectors (4) can be positioned on a vehicle leaf spring assembly (6) to provide a limited movement between these components. For example the bolt (8) securing the upper ends of the side arms (5) to the eye of the leaf spring (3) can be fitted with a special lock nut assembly to prevent relative movement of the components causing the nut to unscrew from the bolt. The lower ends of the arms can be held in spaced relationship in any convenient manner which will prevent them from being clamped tight against the side of the vehicle leaf spring assembly. A stepped bolt and self-locking nut can be used to ensure that this does not happen. The invention provides a spring stabiliser which is simple but effective and reliable and not easily damaged during even severe working conditions.

Claims: A vehicle spring stabilizer unit comprising a leaf spring (3) for mounting above the vehicle axle (2), a connector (4) pivotally secured at each end of the leaf spring for connecting the leaf spring to a vehicle spring assembly (6) below the vehicle axle (2), each connector (4) including a pair of opposed members (5) for embracing the vehicle spring assembly (6), characterised in that the said members (5) are rigidly spaced apart by a spacer (11) to permit relative translational movement between the members (5) and the vehicle spring assembly (6) when the leaf spring (3) is flexed, the relative movement being accommodated by an anti-friction member (12) disposed between the spacer (11) and the vehicle spring assembly (6). A vehicle spring stabiliser unit as claimed in claim 1 characterised in that the connector (4) is a yoke having opposed arms (5) engageable around the vehicle spring assembly. A vehicle spring stabiliser unit as claimed in claim 2 characterised in that the anti-friction member (12) is a rotatable sleeve on the spacer (11) disposed between the arms (5) of the yoke (14). A vehicle spring stabiliser unit as claimed in claim 3 characterised in that the spacer (11) is carried on a bolt (10) connecting the arms (5) of the yoke. A vehicle spring stabiliser unit as claimed in claim 4 characterised in that the bolt is stepped to form the spacer. A vehicle spring stabiliser unit as claimed in claim 1 characterised in that the leaf spring (3) is secured at each end to the respective connector (4) by a bolt (8) having a bush (9) between the bolt and the leaf spring.

Inventors: LAMBERTI ANTONETTE IRENE, LAMBERTI, ANTONETTE IRENE
Applicants: LAMBERTI ANTONETTE IRENE, LAMBERTI, ANTONETTE IRENE
Application year: 1998
Main classification: B60G11
IPC codes: F16F1, B60G11