Roller type instantaneous safety gear
Structural features: mainly composed of caliper body, roller, spring, lifting device, etc. The roller is its key component, usually cylindrical, and the surface is hardened to improve wear resistance and load-bearing capacity. The caliper body is used to accommodate and support the roller, and the corresponding Raceway and limit device are arranged inside to ensure that the roller can roll within the specified range. The spring provides pre-tightening force for the roller, so that the roller and the guide rail under normal circumstances to maintain a certain gap, the pulling device is used to pull the roller when triggered.
Working principle: When the elevator is overspeed, the lifting device drives the roller to overcome the spring force to move to the guide rail. After the roller contacts the guide rail, the roller will roll along the guide rail and gradually clamp the guide rail under the pressure of the car. Realize the instantaneous braking of the car. Since the contact between the roller and the guide rail is rolling friction, the braking process is relatively stable compared to the wedge type instantaneous safety gear.
Advantages: The rolling friction between the roller and the guide rail during braking reduces the wear on the guide rail and the safety gear itself, and extends the service life. For the case of small clearance of the guide shoe, the roller type instantaneous safety gear can be more flexible to adapt, and its braking performance is more stable and reliable. Commonly used in low-speed heavy-duty freight elevator and other places.
Limitations: The structure is relatively complex, the manufacturing cost is high, and the machining accuracy of rollers and Raceways is also high, otherwise it may affect the braking effect and reliability.