Car sling: Key Component in Elevators
car sling is a fundamental tool predominantly used in hydraulic elevators and rarely in traction elevators. In hydraulic elevators with Side Direct and Indirect systems, the car sling serves as the cabin’s frame. Shoes, rollers, and the parachute are mounted on the car sling, which means the cabin lacks a yoke.
In Indirect systems, a sheave (pulley), shoes, and a frame are assembled on the jack and connected to the car sling via wire ropes. In contrast, in Direct elevators, the car sling lacks a pulley and a parachute. In hydraulic elevators that use car sling, only one pair of rails is required, and these rails are responsible for guiding the jack, the pulley attached to it, and the car sling.
car sling is mostly used in hydraulic elevators but can also be found in traction elevators. The elevator cabin is placed on the car sling, and in addition to the cabin, the emergency braking system or parachute is also installed on the car sling. The elevator jacks exert their driving force on the car sling, causing the cabin to move.
In hydraulic elevators using the car sling system, only one pair of rails is needed for operation. These rails can simultaneously guide the car sling, the jack connected to it, and the idler pulley connected to the jack. In hydraulic elevators, car sling installation is done using two pairs of guide rails, while in traction elevators, a car sling is installed in a reverse and parallel rail setup.
Benefits of Using Car Sling
Using a car sling in hydraulic elevators has numerous advantages. Firstly, it offers easier installation and setup compared to other systems. Secondly, it requires less space in the elevator shaft, as only a pair of rails is sufficient for guidance. Thirdly, due to its simple design and being less costly than more complex systems, the car sling is widely used in various construction projects.
The car sling is a key component in the design and construction of hydraulic and traction elevators, contributing to increased safety and efficiency with its simple installation and high performance. Given its technical features and practical benefits, the car sling is recognized as an effective solution in the elevator industry.
Types of Elevator Car Slings
In hydraulic elevators, car slings are classified into two main categories based on the type of jack: direct side jacks and indirect side jacks.
Direct Side Hydraulic Elevator Car Sling:
The direct side jack car sling has a simple structure and lacks certain components such as a safety gear (parachute), sheave, rope clamp, and other accessories. However, this type of car sling includes a structure that must be strong enough to transfer the jack’s force effectively. The adjustability (regulation) of this car sling depends on the length of the part that needs to be connected to the jack, and the adjustment is usually higher than the leveling of the top shoes of the car sling.
Indirect Side Hydraulic Elevator Car Sling:
The indirect side jack car sling, also known as a 1:2 car sling, is used in indirect systems. The connection of these jacks to the cabin or car sling is done through a sheave and wire rope. Due to the use of wire rope, this car sling must be equipped with safety gear, which is chosen to be an instantaneous type that can operate without a governor. In an indirect side hydraulic elevator car sling, the jack is placed on a base, and its size varies depending on the height of the shaft, the pit, the stroke of the jack, and the length of the jack.
Components of Indirect Side Car Sling:
The indirect side car sling consists of smaller parts such as a jack connection bracket, jack holder, deflection sheave, safety gear, flat and roller shoes, rope clamp, hydraulic sheave, and the car sling structure, including columns, forks, and the jack base column. These components combine to provide a solid and stable structure that can effectively withstand various forces.
Hydraulic elevator car slings comprise numerous primary and secondary components that offer precise design and high performance. One of the main advantages of using car slings in hydraulic elevators is the possibility of using only a pair of rails to guide the car sling, jack, and deflection sheave simultaneously, which reduces costs and simplifies installation and setup.
Elevator Car Sling Structure
The structure or framework is considered the main component in a hydraulic elevator car sling. It must be capable of bearing the weight of the cabin, its load, and the torques exerted by them. This structure is designed in an L-shape, comprising two vertical columns and two horizontal beams known as car sling forks. In this configuration, the cabin rests on the forks and is connected to the columns from the ceiling. Shoes, rollers, and parachutes are also securely attached to the car sling columns.
To enhance the efficiency and proper functioning of the car sling columns and forks across various shaft and cabin dimensions, their lengths should be adjustable. High-quality versions of this component are constructed with bolts and nuts, allowing them to be easily assembled and disassembled.
Hydraulic Elevator Car Sling Guide Shoe:
Shoes are used between the car sling and the rail, available in various types. Typically, two types of shoes are used in the car sling: roller shoes and flat shoes. Due to the greater force exerted by hydraulic car slings on the guide rails, the shoes must have high mechanical resistance. Roller shoes offer higher resistance to the torques exerted and are often used at the bottom of the car sling.
Car Sling Parachute:
The parachute in the car sling is used to prevent the cabin from falling in the event of a sudden breakage of the wire ropes. In all hydraulic elevators with indirect jack car slings and wire ropes, the installation of an instantaneous parachute is deemed essential. In car slings without a governor, the parachute is triggered by a mechanical system comprising plates, springs, and links.
Due to its robust and efficient design, the hydraulic elevator car sling structure plays a critical role in the safety and performance of the elevator. With the ability to adjust the length of the columns and forks, this structure can easily adapt to various shaft and cabin dimensions. This feature facilitates the easy installation and adjustment of the car sling at the project site.
When selecting a car sling, special attention should be paid to the quality of its construction and the materials used. Bolt-and-nut car slings, due to their ease of assembly and disassembly, are considered suitable options for various projects. Additionally, high-quality shoes and reliable parachutes should be used to ensure the safety and proper functioning of the system.
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