One of the main parts of the elevator cabin is the shoe, which has a good effect on the smooth movement of the elevator cabin and the counterweight of the elevator.
The shoes are installed at the bottom and top of the counterweight and the cabin, and their main task is to guide the counterweight and the cabin along the elevator guide rail. Shoes are produced in different types and materials, prices, and qualities.
Contrary to their small appearance, elevator guide shoes serve various purposes within the elevator. They are utilized in all elevators, including traction, hydraulic, and even magnetic ones. As mentioned, the primary role of guide shoes is to aid smooth movement, reduce the sliding of the elevator car, and maintain the balanced weight along the elevator guide rails. These factors collectively contribute to enhancing the quality of elevator movement.
Vibrations and tremors commonly occur as the elevator car passes the connecting point of the guide rails, but the guide shoes neutralize these vibrations, providing uniformity and smoothness in the movement while ensuring the balanced weight and cabin are well-supported.
In general, guide shoes fall into three categories:
– Sliding Guide Shoes: These are the most common type of guide shoes and include various types of inserts such as rubber, and polyurethane (also known as gel). Sliding guide shoes, due to their full contact with the rail and absence of grooves, tend to transfer surface irregularities and vibrations from the rail connection to the elevator car. However, certain types of guide shoes, like Hitachi guide shoes, absorb a considerable amount of impact resulting from irregularities.
The maximum usable speed for these guide shoes is 2.5 meters per second.
– Roller Guide Shoes: These shoes are positioned with three rollers on three faceted rail surfaces. The combination of these rollers and their base forms the roller guide shoe, which does not slide. Each roller has a spring that absorbs and prevents a significant portion of irregular impacts from being transferred to the elevator car. The performance of roller guide shoes is significantly influenced by the materials used for the bearings and polyurethane.
– Fixed Guide Shoes
Each of these guide shoes has its specific advantages and disadvantages, and it’s challenging to determine which is the best. However, sliding guide shoes, especially those with rubber inserts, are generally more popular.
The part of the elevator guide shoe that adheres to the guide rail and moves over it, is the guide shoe insert. It is made of various materials including polyurethane, polyamide, Teflon, and gel.
The dimensions of the insert vary in proportion to the rail. Each type of rail (e.g., T9, T16, etc.) has its specific guide shoe insert, and based on how it sits on the rail and the pressure exerted on it due to the load capacity of the elevator, a suitable insert with appropriate dimensions is used, ranging from stronger to weaker.
The body of the guide shoe insert can be made from various materials. It may be produced from steel sheets, cast iron, or die-cast, the majority of roller guide shoes are die-cast.
The material of the guide shoe body and insert are not necessarily the same and can be manufactured from entirely different materials.
In a standard elevator, both the car and the counterweight are equipped with guide shoes. In normal circumstances, 90% of elevators use four guide shoes for the four directions of the elevator car and four guide shoes for the counterweight.
Elevator guide shoes need to be inspected over time and repaired if necessary. Roller guide shoes do not require continuous monthly oiling, while sliding guide shoes, due to their plastic inserts, need monthly oiling. Elevator guide shoes are equipped with springs that need to be properly adjusted during installation. The spring should not be overly tight or too loose. If the spring is too tight, it may exert pressure on the elevator motor and cause it to malfunction. On the other hand, if the spring is too loose, it can transfer vibrations and sliding movements from the guide rails to the elevator car. Failure to promptly address worn-out inserts can lead to elevator vibrations and misalignment of the elevator doors.
In addition to adjusting the springs, the distance between the insert and the main body of the guide shoe also needs to be adjusted in sliding guide shoes. Therefore, adjusting the springs is considered a part of elevator service and maintenance. In general, elevators need to be serviced and repaired at specific intervals. If the guide shoes are regularly oiled and serviced, their useful life is also extended. Additionally, the guide shoe inserts should be replaced every 8 months.