Electric barriers are widely used, e.g. at road toll stations. Sometimes they accidentially hit an entering vehicle, damaging the vehicles and possibly injuring the drivers. These accidents can be avoided by providing the driving mechanism with a clutch. Then, if the barrier arm is going to hit a vehicle, further downward movement stops and the arm automatically returns to the vertical position, thus keeping the barrier in position and ensuring the safety of the users.
Charge barriers technical specifications. Transportation Ministry of China, JT/T428.1, 2000.
2.
Joint writing group. Machine Design Record Book, 2002 (Beijing Chemical Industry Publishing House, Beijing, PR China).
3.
Mechanical principle and mechanical parts teaching and research group at Northwest University of Technology. Machine Designing, 1979 (People's Education Press, Beijing, PR China).
4.
YangS. X.Mechanical mechanism to prevent electric barriers from hitting vehicles. Chinese Pat. ZL99214008.0, 2000.
