The ornamental design for a headlamp for vehicles, as shown and described.
1. Head lamp for vehicles
1.1: Perspective
1.2: Front
1.3: Back
1.4: Right
1.5: Left
1.6: Top
1.7: Bottom
1.8: Perspective
1.1is a top, front, and left side perspective view of a head lamp for vehicles embodying our new design; 1.2is a front elevation view thereof; 1.3is a rear elevation view thereof; 1.4is a right side elevation view thereof; 1.5is a left side elevation view thereof; 1.6is a top plan view thereof; 1.7is a bottom plan view thereof; and 1.8is a top, rear, and right side perspective view thereof.