WEBVTT

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>> This is a continuation of
lab 3 part 2 and 3 of the lab 3.

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We start by making a copy
ok of what we already have.

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Part 1 basepoint will be the
origin here and then making sure

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that it will be copied
perfectly horizontally so I turn

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on the ortho toolbar, press
enter after clicking on the copy

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and then what we're going
to do here is we are going

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to rotate the cam by 15 degrees
and determine the final location

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of the follower for
it to stay tension.

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So rotate select the cam, press
enter to finish the selection

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and base point is the
origin and 15 degrees

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that rotated the
cam by 15 degrees.

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Next, we are going to create a
vertical construction line ok

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that identifies the vertical
path of the follower.

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Ok and I'm going to
next create a circle

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that is also a construction line
that defines the final position

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of the center of the followers.

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So its center is at par 20 here
and it's going to 45 units away

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because the cam has to
stay externally tangent

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to the followers so
20 plus 25 is 45.

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What we need to do now is move
the location of the follower.

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Select the follower, the base
point is this original center

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and then the second
basepoint is the intersection

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of the construction circle with
a vertical construction line

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and if you rooted
it correctly the cam

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and the follower should
remain tangent to each other.

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Let's erase the construction
lines

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and that will give us part 2.

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For part 3 you're first going to
copy what we have for part 2 ok,

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press enter to end selection.

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Here's the first base point,
make sure that ortho is on

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and make a copy to the
right of the second drawing.

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Press enter to finish in a
copy and what we're going

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to do next is the follower
is going to be moved

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down by 20 units,
20 millimeters ok

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and as a result the cam should
rotate accordingly in order

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for it to remain
tangent to the follower.

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So move then select
the follower,

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press enter to finish
the selection.

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Ok first displacement is
the center of the follower

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and then move it down by saying
at 0, minus 20 to indicate

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that it's moving down by 20 so
the follower moves down by 20.

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Then we need to determine how
much should the cam rotate

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counterclockwise in order to
remain tangent to the follower.

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So of the final position it's
the R100 the big arc that's

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going to be externally
tangent to the arc 25.

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So first we put a
construction circle

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of radius 125 that's
equal to 100 plus 25

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and then another construction
circle of radius 60,

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the 60 is the location of
the center of the R100,

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the cam rotated is always
going to be around that.

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Now we're going to create a
line from the current location

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of the center of the R100 ok
and I unselect ortho and then go

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to the origin of the cam and
then go to the intersection

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of the two circles, which
would be the final location

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of the center of R100.

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Then to determine the amount of
rotation needed this is the line

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for the origin of the
position of the center of R100

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and to the final location of
the line after that rotation.

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It says 21 degrees but we
need to display by going

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to dimension tile, modify

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and then increase the angular
measurements to 5 decimal cases

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and if we zoom in the angle
is 20.85133.tml that we need

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to rotate the cam by in order to
remain tangent to the follower.

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So I'm going to rotate
now the cam, enter,

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the base point should
be the origin ok

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and then the angle should
be as shown here 20.85133.

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Enter that rotated
the cam accordingly

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as you can see the
2 remain tangent

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at the final position
we're done we just need

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to erase the 2 construction
circles.

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The R125 and the
R60 and we're done.