Overspeed braking mechanism for a stairlift
An overspeed braking mechanism for a stairlift includes: a main shaft driven by a motor to rotate; a claw member connecting with the main shaft to thereby rotate synchronously with the main shaft and having a tooth; a cam member connecting with the claw member and having an abutting portion spaced apart from the tooth of the claw member radially by a predetermined angle; a driven unit having a cam contact portion, wherein the abutting portion of the cam member abuts against the cam contact portion to cause the driven unit to swing, whereas a pawl portion of a claw contact member engages with the tooth of the claw member and has a switch contact portion; and a micro switch adapted to be touched by the switch contact portion, controlling the motor to drive the main shaft to rotate.
1. An overspeed braking mechanism for a stairlift, mounted on a base, the overspeed braking mechanism comprising:
a main shaft driven by a motor to rotate;
a claw member connecting with the main shaft to thereby rotate synchronously with the main shaft and having a tooth;
a cam member connecting with the claw member and having an abutting portion spaced apart from the tooth of the claw member radially by a predetermined angle;
a driven unit having a cam contact portion, wherein the abutting portion of the cam member abuts against the cam contact portion to cause the driven unit to swing, whereas a pawl portion of a claw contact member engages with the tooth of the claw member and has a switch contact portion;
a restoring element causing the driven unit to swing, thereby allowing the cam contact portion to tilt closer toward the cam member; and
a micro switch adapted to be touched by the switch contact portion, thereby controlling the motor to drive the main shaft to rotate.
2. The overspeed braking mechanism for a stairlift in accordance with claim 1 , wherein the driven unit comprises a cam contact member connected to the claw contact member.
3. The overspeed braking mechanism for a stairlift in accordance with claim 2 , wherein the switch contact portion is defined at the claw contact member.
4. The overspeed braking mechanism for a stairlift in accordance with claim 2 , wherein the driven unit has a roller pivotally connected to the cam contact member, and the roller externally, circumferentially defines the cam contact portion.
5. The overspeed braking mechanism for a stairlift in accordance with claim 4 , wherein the restoring element is connected between a restoring connected portion of the driven unit and the base.
6. The overspeed braking mechanism for a stairlift in accordance with claim 5 , wherein the cam contact member and the claw contact member are coupled together and fixed in place with a penetrating pipe, whereas two bushings are inserted oppositely into an internal hole of the penetrating pipe, respectively, and fitted around a pivot.
7. The overspeed braking mechanism for a stairlift in accordance with claim 4 , wherein the cam contact member and the claw contact member are coupled together and fixed in place with a penetrating pipe, whereas two bushings are inserted oppositely into an internal hole of the penetrating pipe, respectively, and fitted around a pivot.
8. The overspeed braking mechanism for a stairlift in accordance with claim 2 , wherein the cam contact member and the claw contact member are coupled together and fixed in place with a penetrating pipe, whereas two bushings are inserted oppositely into an internal hole of the penetrating pipe, respectively, and fitted around a pivot.
9. The overspeed braking mechanism for a stairlift in accordance with claim 1 , wherein the restoring element is connected between a restoring connected portion of the driven unit and the base.
10. The overspeed braking mechanism for a stairlift in accordance with claim 9 , wherein the driven unit comprises a cam contact member connected to the claw contact member, wherein the cam contact member and the claw contact member are coupled together and fixed in place with a penetrating pipe, whereas two bushings are inserted oppositely into an internal hole of the penetrating pipe, respectively, and fitted around a pivot.