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What is the tolerance accepted in the elevator industry?
As an example, the National Elevator Industry’s tolerance for vertical alignment of elevator shaft walls is a maximum of 2 inches. However, that is at odds with ACI 117-90, “Standard Specifications for Tolerances for Concrete Construction and Materials,” which permits a 6-inch maximum tolerance.
What type of screw would be used to hold a pulley on a shaft?
A set screw, also known as a blind screw or a grub screw, is a type of screw generally used as a detent to secure an object within or against another object, usually without using a nut (see bolts compared with screws). The most common examples are securing a pulley or gear to a shaft.
What is the distance from the crest of one thread to the crest of the next thread called?
PITCH/TPI: The pitch is the distance from the crest of one thread to the next in milimeters (mm). TPI (threads per inch) is used by inch thread.
What is done with pipe threads to ensure good seals?
Simply put, thread sealant is a material that fills the gaps at threaded pipe connections, preventing fluids from leaking out. Besides creating fluid-tight seals, pipe thread sealants also lubricate the threads, making assembly quicker. Pipe thread sealants come in two general varieties—paste and tape.
What is the maximum practical speed of a lift?
Lift speed is usually expressed in m/sec (metres per second). Platform Lifts under the Machinery Directive are limited to a maximum speed of 0.15m/sec (150mm per second).
What is thread crest?
The crest of a thread is the prominent part of a thread, whether internal or external. The root is the bottom of the groove between the two flanking surfaces of the thread whether internal or external. The flanks of a thread are the straight sides that connect the crest and the root.
How do you calculate lift speed?
Lift speed is usually expressed in m/sec (metres per second). Platform Lifts under the Machinery Directive are limited to a maximum speed of 0.15m/sec (150mm per second). In order to calculate the time that the lift will take to complete a single journey you will need to divide the total lift travel by the speed.
What should the clearance be between bearing bore and shaft?
For these conditions, we recommend an interference fit between the shaft and bearing bore. The level of interference will increase for heavier loads. When shaft conditions are stationary, and the radial load is constant, a moderate clearance fit between the shaft and bearing bore is an option. Selecting the Proper Housing Fit
Can a bearing shaft and housing fit be the same?
The resulting fit will be dependent on the tolerances of two points of contact – either the bearing bore and the shaft or the housing and bearing O.D. It will be unusual for a shaft and housing fit to be the same. One fit requires a clearance fit, the other, generally, the rotating ring, will require an interference fit.
When to use interference fit between bearing and shaft?
For these conditions, we recommend an interference fit between the shaft and bearing bore. The level of interference will increase for heavier loads. When shaft conditions are stationary, and the radial load is constant, a moderate clearance fit between the shaft and bearing bore is an option.
What does a fit above a bearing mean?
Shaft fits represented above the bearing bore indicate an interference fit. Housing fits above the bearing O.D. represent a clearance fit, while those below the bearing O.D. represent an interference fit. Some letter classes of fits allow both a clearance and a slight interference with the bearing component.