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Lesson 6 Scorm Package - Coggle Diagram

- - - - Definition
        
        Has an arrow head at each end
    - - Definition
        
        Base dimensions, units usually in (mm) is not indicated on every dimension text but at the bottom corner of the drawing.
    - - Definition
        
        Extension lines continue or extend from the surface of the object and establish the size of the dimension. They do not touch the object lines and extend slightly past the dimension line.
    - - Definition
        
        A gap between the object surface and the extension line, so it is not confused with the visible lines of the model
    - - Definition
        
        Defines how much the dimensions is allowed to deviate. ±0.2 is an example of a tolerance.
  - - - Definition
        
        Should only be used if the function of the object would not be affected by the accumulation of the tolerances.
    - - Definition
        
        Uses both chain and parallel Dimensioning
    - - Definition
        
        Placing arrow head in the middle might be difficult to read the numbers hence arrow heads can be put outside for reading easier.
    - - Definition
        
        To dimension multiple same dimensions, Use N x Dimension. In the above diagram, 4 x 6 indicates four circles of diameter 6. Which are the four circles? Ans: the outer circles
    - - Definition
        
        Radial dimensions start with capital 'R'.
    - - Definition
        
        Simplifies parallel dimensions in order to reduce the space used on a drawing.
    - - Definition
        
        Circle is dimensioned by its Diameter, Arc is by Radius and Hole is by Centreline.
    - - Definition
        
        Consists of several dimensions originating from a common reference surface (also known as the datum).
    - - Definition
        
        marked with a curved dimension line and has the degree symbol
  - - - Same dimension should not be repeated on different views, or the same information need not be given in two different ways
- - - - Bilateral tolerance
        
        Defnition
        
        Allowed to vary in two directions from the specified dimension. Both directions need not vary by the same amount.
      - Unilateral Tolerance
        
        Definition
        
        Allowed to vary in only one direction
      - Limit Tolerance
        
        Definition
        
        The upper and lower limits of the dimension are specified
    - - Formula
        
        Tolerance = Upper Limit - Lower Limit
    - - Clearance Fit
        
        Example
        
        Maximum diameter for the shaft is 49.7mm and Minimum diameter for the hole is 49.9mm, there is sufficient clearance for the shaft to interface with the hole hence this is called, clearance fit.
        
        Application
        
        There would still be an allowance for two parts to move, such as in a door hinge.
      - Interference Fit
        
        Example
        
        Minimum shaft diameter is 49.8mm and Maximum hole diameter is 49.5mm, hence its called interference fit.
        
        Application
        
        Difficult to move or remove the two interfacing parts. Usually alot of forced is needed to remove the two parts. Eg. shafts that are fitted thru ball bearings so that the shaft does not slip.
- - - - Types of joints
        
        Revolute
        
        Definition
        
        Has a single rotational degree of freedom, much like a hinge.
        
        Slider
        
        Definition
        
        A slider joint has a single translational degree of freedom. It is used for components that slide along one another
        
        Cylindrical
        
        Definition
        
        A cylindrical joint provides two degrees of freedom: one translational and one rotational. Components joined with a cylindrical joint always rotate around the same axis.
        
        Pin Slot
        
        Definition
        
        A pin slot joint also allows two degrees of freedom, but components can rotate around different axes.
        
        Planar
        
        Definition
        
        A planar joint allows three degrees of freedom. It allows two directions of translation in a plane and a single rotational direction normal to that plane. It is useful for joining two components so they can rotate while sliding across the plane.
        
        Rigid
        
        Definition
        
        Fixes two components to one another; it provides no degrees of freedom.
        
        For E112, we are focusing on Rigid Joints and Revolute Joints
        
        Ball
        
        Definition
        
        A ball joint has two degrees of rotational freedom: pitch and yaw. Pitch allows components to rotate around the Z axis. Yaw rotates components around the X axis.