Torsion device and torsion washer

A torsion device, comprising:

• a plurality of torsion washers stacked in one row and each having a base portion and at least one elastic unit extended from the base portion, the at least one elastic unit of each of the torsion washers including:
• at least one external elastic arm;
• a torsion-adjusting arm arranged inside of the at least one external elastic arm, wherein a space surrounded by the base portion and the at least one external elastic arm is divided by the torsion-adjusting arm into a hole and at least one slot in air-communication with the hole, and wherein the hole has a center, a distance between the center and the at least one external elastic arm is defined as a radius, and a distance between the center and the torsion-adjusting arm is defined as an interference distance and is smaller than the radius;
• and
• at least one shaft coupling through the hole of each of the torsion washers and defining a central axis, wherein an outer surface of the at least one shaft has a non-contact surface and a contact surface, a distance between the contact surface and the central axis is substantially equal to the radius, a distance between the non-contact surface and the central axis is smaller than the interference distance, and the contact surface of the at least one shaft contacts the at least one external elastic arm of each of the torsion washers and selectively contacts the torsion-adjusting arm of each of the torsion washers,
• wherein in each of the torsion washers, the torsion-adjusting arm has a first central angle corresponding to the center of the hole and having σ1 degrees, wherein the contact surface has a second central angle corresponding to the central axis and having σ2 degrees, and the non-contact surface has a third central angle corresponding to the central axis and having σ3 degrees, and wherein σ2+σ3=360, σ1<σ2, and σ1<σ3;
• and
• wherein the at least one shaft is rotatable relative to the torsion washers along the central axis from a first position to a second position via a transition position, wherein when the at least one shaft is in the first position, the torsion-adjusting arm of each of the torsion washers does not contact the at least one shaft, and each of the torsion washers generates a first torque, wherein when the at least one shaft is in the transition position, the torsion-adjusting arm of each of the torsion washers partially contacts the contact surface of the at least one shaft, and each of the torsion washers generates a gradually rising torque, and wherein when the at least one shaft is in the second position, the torsion-adjusting arm of each of the torsion washers entirely contacts the contact surface of the at least one shaft, and each of the torsion washers generates a second torque larger than the first torque.

A torsion device, comprising:

• a plurality of torsion washers stacked in one row and each having a base portion and at least one elastic unit extended from the base portion, the at least one elastic unit of each of the torsion washers including:
• at least one external elastic arm;
• a torsion-adjusting arm arranged inside of the at least one external elastic arm, wherein a space surrounded by the base portion and the at least one external elastic arm is divided by the torsion-adjusting arm into a hole and at least one slot in air-communication with the hole, and wherein the hole has a center, a distance between the center and the at least one external elastic arm is defined as a radius, and a distance between the center and the torsion-adjusting arm is defined as an interference distance and is smaller than the radius;
• and
• at least one shaft coupling through the hole of each of the torsion washers and defining a central axis, wherein an outer surface of the at least one shaft has a non-contact surface and a contact surface, a distance between the contact surface and the central axis is substantially equal to the radius, a distance between the non-contact surface and the central axis is smaller than the interference distance, and the contact surface of the at least one shaft contacts the at least one external elastic arm of each of the torsion washers and selectively contacts the torsion-adjusting arm of each of the torsion washers,
• wherein the at least one shaft includes a first segment and a second segment, the first segment couples through a part of the torsion washers, the second segment couples through the other part of the torsion washers, and a central angle of the non-contact surface of the first segment is different from that of the second segment.