The ornamental design for a sweatbandinsert for hardhat headbands, as shown and described.
FIG. 1 is a front perspective view of a sweatband insert for hard hat headbands, showing my new design;
FIG. 2 is a rear perspective view thereof;
FIG. 3 is a side perspective view thereof;
FIG. 4 is a front view thereof;
FIG. 5 is a rear view thereof;
FIG. 6 is a left side view thereof with a right side view being a mirror image;
FIG. 7 is a top view thereof;
FIG. 8 is a bottom view thereof;
FIG. 9 is a front perspective view of the sweatband insert of hard hat headbands depicted in a fastened orientation; and,
FIG. 10 is an upward perspective view of a sweatband insert for hard hat headbands depicted as in the fastened orientation attached to a headband of a hard hat.
The broken line showing of a hard hat in FIG. 10 is for the purpose of illustrating environmental structure and forms no part of the claimed design.