Model 14: Stepdwell motion of a belt, used
in a paper cutting machine
Kinematic scheme:
Dimensions:
|
Dimensions
[m] |
a |
0.060 |
b |
0.024 |
c |
0.140 |
d |
0.120 |
e |
0.056 |
f |
0.264 |
g |
0.076 |
h |
0.170 |
k |
0.252 |
m |
0.150 |
n |
0.174 |
u1 |
0.049 |
u2 |
0.280 |
r1 |
0.0334 |
r2 |
0.0143 |
a0 |
-0.9 rad |
b0 |
2.85 rad |
Explanation:
The belt part at the green slider (between the rolls
at distance m) performs a step-dwell motion. The green slider is driven by the
inverted crank-slider mechanism (oscillatory motion). When moving to the right,
the slider velocity compensates the constant belt speed. While the belt has no
velocity, some device (the yellow block attached at the crank-slider mechanism)
can operate on the belt. The diagram below shows the step-dwell motion. This
machine can for instance be used for cutting paper sheets supplied from a drum
of paper.
Literature
Remarks: To
perform the step-dwell motion, theoretically the following condition must hold: r1=2a(h-d)/(a+d)=0.0333
m.
In the model a toothed belt wheel with 42 teeth at
pitch 5mm is used, which yields r1=0.0334 m. The model has the
option to adjust the position of the pin-joint on the green slider,
perpendicular to the sliding direction, to adapt the h-value of the condition.