The ornamental design for a leafspring, substantially as shown and described.
FIG. 1 is a perspective view of a leaf spring showing our new design, the claim is shown broken apart in FIGS. 1-3, 6, and 7 to represent indeterminate length.
FIG. 2 is a top view.
FIG. 3 is a bottom view.
FIG. 4 is a front end view.
FIG. 5 is a rear end view.
FIG. 6 is a left side view; and,
FIG. 7 is a right side view.
The broken line showing of the holes in FIGS. 1-3 is included for the purpose of illustrating portions of the leaf spring and forms no part of the claimed design.