49ers notes: Mobile tackling dummies added to 49ers practice

SANTA CLARA -- Chip Kelly, known for his smarts, once tried to build a dummy.

"It broke after the first tackle," the 49ers coach said Wednesday. "It went really fast, but . . .”

The idea of a motorized tackling dummy was perfected by a friend of Kelly's, Dartmouth coach Buddy Teevens, who developed one that not only moves but that can withstand the pounding of an NFL training-camp practice.

The 49ers ordered three -- they officially are known as Mobile Virtual Players -- and put them to the test this week in practice. The offensive linemen were the first to take a whack at the new recruits.

Kelly said the main advantage -- which was Teevens' inspiration -- is that his players can practice…