need1of those bull's horn shaped locks that janitors use to secure double swinging doors.What r they called?

Question

I need to secure double swinging doors at work and I cannot find the name of the device. It is a u-shaped bar that hooks the push handles of swinging doors. The janitors at my high school used them to secure the door from the inside. Does anyone know what they're called?

Answer 1

They are bicycle locks