Dual-stage tapered leaf spring for a trailer
AssigneeDetroit Steel Products Co., Inc.
InventorsMark A. Heckenliable, Dewayne B. Williams, Robert J. Dooley
Life of this patent
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Abstract
The present invention discloses a lightweight dual-stage tapered leaf spring assembly for use in heavy-duty trailer suspension applications. The dual-leaf tapered leaf spring assembly has a main or first tapered leaf defining a first stage rate and a second tapered leaf operable to define a second stage rate. The first and second leafs are formed to include a tapered thickness profile which closely approximates a true modified parabolic taper. The "approximated" modified parabolic profiles for each of the main and second leafs are adapted to provide a smooth non-linear transition between the first and second stage rates.
Claims14
In a suspension system for a trailer having axle means and a chassis frame, first and second hanger means mounted on each side of said chassis frame, and a dual-stage tapered leaf spring operably coupled to said axle means and disposed between said first and second hanger means for damping the relative movement between said axle means and said chassis frame, said dual-stage tapered leaf spring comprising:
- a first leaf member having its upper end surfaces in sliding contact with cam surface means provided on said first and second hanger means, said first leaf member having a first tapered thickness profile;
- and
- a second leaf member disposed below and coupled to said first leaf member such that its upper end surfaces are adapted to move between positions of disengagement and engagement with lower end surfaces of said first leaf member in response to deflection of said leaf spring means, said second leaf member having a second tapered thickness profile;
- wherein each of said first and second tapered thickness profiles include a series of more than three successive linearly tapered increments which each define a different amount of thickness taper per unit of length measurement, said linearly tapered increments having different incremental tapers sequentially arranged and configured to track a modified parabolic taper profile.
In a suspension system for a trailer having axle means and a chassis frame, first and second hanger means mounted in tandem on each side of said chassis frame, a variable rate dual-leaf spring assembly operably coupled to said axle means and disposed between said first and second hanger means for damping the relative movement between said axle means and said chassis frame, said variable rate dual-leaf spring assembly comprising:
- a first elongated leaf member having a portion of its upper end surfaces in sliding contact with cam surface means provided on said first and second hanger means, said first leaf member having a first tapered thickness profile;
- and
- a second elongate leaf member disposed below and coupled to said first leaf member such that a portion of its upper end surfaces are adapted to move between positions of disengagement and engagement with lower end surfaces of said first leaf member in response to deflection of said dual-leaf spring assembly, said second leaf member having a second tapered thickness profile;
- wherein said first and second tapered thickness profiles include a series of more than three successive linearly tapered increments which each define a different amount of thickness taper per unit of length measurement, said linearly tapered increments having different incremental tapers sequentially arranged and configured to approximate a modified parabolic taper profile, said upper end surfaces of said second leaf member being normally disengaged from said lower end surfaces of said first leaf member when said trailer is operating in a first loaded condition such that engagement of said upper end surfaces of said first leaf member with said cam surface means causes said dual-leaf spring assembly to provide a soft damping characteristic, and wherein said upper end surfaces of said second leaf member are adapted to engage said lower end surfaces of said first leaf member when said trailer is operating in a second loaded condition for providing a firmer damping characteristic.
Dependencies are inferred from the claim text.