Leaf spring assemblies for motor vehicles often include a plurality of leaf springs stacked upon one another. The resilient rate of a leaf spring assembly can be determined in part by the number of leaves. The plurality of leaves are commonly secured to each other by one or more clips which circumscribe the plurality of leaves. Commonly, the clips are positioned near the axial ends of the leaves.
Leaf spring assemblies have also been designed to provide a first resilient rate for a predetermined amount of movement and then provide a second higher resilient rate or any movement beyond the predetermined amount. These leaf spring assemblies are commonly called two stage leaf spring assemblies. Two stage leaf spring assemblies are presently incorporated in many different compact pickup trucks.
Two stage leaf spring assemblies commonly have a second stage leaf aligned below a stack of first stage leaves. The second stage leaf is attached to a central portion of the stack of leaves. The second stage leaf spring has its outer axial ends spaced below the first stage leaves. The second stage leaf undergoes no flexure while the first stage leaves are flexed from an unflexed first position to a second intermediate position. When the first stage leaves are in the second intermediate position, the space between the outer ends of the second stage leaf and the first stage leaves is closed and the outer ends abut the first stage leaves. Further flexure of the leaf spring assembly beyond the second position causes the second stage leaf to flex, thus adding to the resilient rate to the leaf spring assembly.
The second stage leaf is secured to the spring seat and to the first stage leaves only at a center portion. Consequently, the second stage leaf may respond to torque about a vertical axis and rotate with respect to the first stage leaves. Torque is introduced by rotation of the axle about a vertical axis. Torque is transferred to the leaves via a spring seat fixed to the axle and seating the center portion of the leaves. The rotation about a vertical axis of the second stage leaf relative to the first stage leaves is commonly referred to as splaying. Splaying of the second stage leaf results in one end protruding outward from the leaf spring assembly and the other end protruding inward toward the central longitudinal axis of a motor vehicle. Even slight splaying is visually noticeable and may give a false impression to a motor vehicle operator that his vehicle needs repair. Excessive splaying can defeat the two stage function of the leaf spring assembly. The outer ends of the second stage leaf may splay sufficiently such that their outer ends no longer are able to contact the first stage leaves and, hence, will not undergo flexure. As a result, the second stage leaf may become nonfunctional.
Attempts have been made to minimize splaying of the second stage leaf. A clip has been mounted to the lower side of the second stage leaf near the outer ends thereof. The clip extends upwardly past the gap between the first stage leaves and second stage leaf and surround the first stage leaves. Furthermore, to be effective, the clip must be long enough to extend above the first stage leaves to take into account upward movement of the first stage leaves relative to the second stage leaf when the vehicle goes into rebound. The overall length, particularly the portion below the first stage leaves, presents an undesirable appearance. In addition, the long clip is an added expense which should be minimized.
An anti-splay device is desired which is relatively inexpensive and unobtrusive.
USPTO Backgrounds
USPTO Backgrounds