Lecture 3

Question 1

What are the different types of slides?

Answer 1

Extruded Linear Slide

Carriage Slide - guided by wheels

Complete carriage slide with lead screw

Extending drawer screw - using ball bearings

Question 2

What are the effects of the dimension of a slide?

Answer 2

If the length of the acrylic is shorter than the width you get friction and sticking of the length of the side

Question 3

How does a spidle linear drive work?

Answer 3

Lead screw rotates causing the mating nut to move up and down the shaft

Question 4

For a trapezoidal thread, what is pitch?

Answer 4

The distance between the groves. However, it is often the case that multiple threads are put on a single shaft which makes for the definition of a ‘LEAD’ screw

Question 5

What is the ISO standart nomenclature for the trapezoidal metric lead screw?

Answer 5

Tr (Diameter) x (Lead Distance - travel distance for one rotation of the lead screw)

Question 6

What is step angle?

Answer 6

Defined as the degrees per step and they are often either 1.8o/step or 0.9o/step i.e. If the motor driver induces a single stop change then it will rotate the shaft by the specified angle

Question 7

How are pulleys specified by?

Answer 7

Belt profile
Tooth pitch
Number of teeth
Belt width
Bore diameter

Question 8

What are closed timed belts?

Answer 8

Custom designed for a fully engineered product or the system is designed around an existing production part

Design must have sufficient tension adjustment to remove, replace and tension the belt

Continuous travel

Question 9

What are open timed belts?

Answer 9

Cut to required length

Requires tensioning mechanism

Requires suitable anchor methods

Facilitates multiple methods of carriage drive motion

Question 10

What are the primary advantages of rack and pinion?

Answer 10

Rigidity
Precision
Multiple pinons on the same rack
Easy expandability