The incident happened on Tuesday morning at Burnet Elementary in east Houston, police said.
Curtis Emmett is now home from the hospital after he says he spent two days being treated for injuries to his left arm.
He said he had just finished work on Tuesday morning when his truck started shaking.
"He started whacking on my window," Emmett said.
Emmett said Raul DeHoyos, a man he knew from working in the neighborhood, started attacking him. Emmett got out of his truck and said he defended himself.
"I threw a haymaker. 'Hallelujah!' I knew this. I wasn't going to let him win just because you're 34 and I'm 92. I want you to know you got a tiger in your truck," he said.
Another crossing guard, Gilbert Reyna, said he called 911.
"The guy was pushing him. At the same time, he was swinging that wrench, hitting him on the arm, trying to get Mr. Curtis to cut him loose," Reyna said.
DeHoyos is now in jail, charged with injury to an elderly person.
Meanwhile, Emmett, a Korean War veteran, hopes to return to work soon.
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