Abstract: Disclosed is a length-variable bumper capable of adjusting the length of a vehicle body to lengthen a time interval over which momentum changes upon collision. The length-variable bumper includes a bumper member primarily absorbing collision energy, a collision energy absorbing member foldable in a longitudinal direction, and an operation unit configured to transit the collision energy absorbing member to an unfolded state when a vehicle speed is a predetermined level or more and to transit the collision energy absorbing member to a folded state when the vehicle is the to predetermined level or less. The collision energy absorbing member has one end connected to a frame of the vehicle and the other end connected to the bumper member and configured to be deformed upon collision to secondarily absorb the collision energy.

Abstract: A disk friction clutch apparatus using a self-energizing effect is disclosed. The clutch apparatus includes a drive friction disk connected to a drive shaft, a driven friction disk connected to a driven shaft, a push member configured to press the driven friction disk against the drive friction disk at an engagement position of a clutch, and an operation unit configured to shift the push member from the release position of the clutch to the engagement position. The operation unit is operated to increase a force of the push member to press the driven friction disk when the push member located at the engagement position of the clutch receives a force of rotating the drive shaft. Since the clutch apparatus employs a self-energizing effect, it is possible to fasten the clutch with a small force.

Abstract: Disclosed is a length-variable bumper capable of adjusting the length of a vehicle body to lengthen a time interval over which momentum changes upon collision. The length-variable bumper includes a bumper member primarily absorbing collision energy, a collision energy absorbing member foldable in a longitudinal direction, and an operation unit configured to transit the collision energy absorbing member to an unfolded state when a vehicle speed is a predetermined level or more and to transit the collision energy absorbing member to a folded state when the vehicle is the to predetermined level or less. The collision energy absorbing member has one end connected to a frame of the vehicle and the other end connected to the bumper member and configured to be deformed upon collision to secondarily absorb the collision energy.

Abstract: A disk friction clutch apparatus using a self-energizing effect is disclosed. The clutch apparatus includes a drive friction disk connected to a drive shaft, a driven friction disk connected to a driven shaft, a push member configured to press the driven friction disk against the drive friction disk at an engagement position of a clutch, and an operation unit configured to shift the push member from the release position of the clutch to the engagement position. The operation unit is operated to increase a force of the push member to press the driven friction disk when the push member located at the engagement position of the clutch receives a force of rotating the drive shaft. Since the clutch apparatus employs a self-energizing effect, it is possible to fasten the clutch with a small force.