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for
continuous stepping motions in one
direction:
Index
drives and rotary index tables
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for
oscillating motions:
Oscillating
drives
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for
Pick'n'Place motions:
Handling
units
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for
rectilinear lifting motions:
Linear
units
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Index
drives and rotary index tables generate stepping
motions of the output shaft through an evenly
formed rotary motion of the drive.
How
does it function?
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the
motion sequence in general: |
![Animation](aaaaaaaaaaa_dosyalar/image.gif) |
the
input shaft → rotates
continuously, advancing one cycle for each
revolution. The system runs through the
index-angle and dwell-angle ranges as it does
so.
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←
the output element (shaft, rotary plate)
advances
one step whenever the system runs through the
index angle and stops whenever the system runs
through the dwell angle. |
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The movement of the output is
determined by a Law of motions. This is a
mathematical function which stipulates the
respective position of the output for every
position of the drive. In case of the
specification of a drive rotary speed, the speed
and acceleration of the output is also
determined.
The laws of motion of our stepping
gear and rotary indexing tables are selected in
such a way that an extremely harmonic thrust
and jolt-free motion is realized.
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The Number of stations
n establishes how often the output element
pauses during a complete revolution, thus
determining the size of each step Ψ.
Ψ =
360° / n
Depending on the construction
type of the gear, we supply gears with the
following number of stations on a standard basis:
1, 2, 3, 4, 5, 6, 8, 10, 12, 16, 18, 20, 24, 32
Special number of stations can often be made but
not always reasonable to realize for technical
reasons (e.g.: 29). In such cases, it is always a
good idea to consider a step-down unit which is
secondary to the index drive.
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the
impact of the input speed and of the index/dwell
angle:
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If the gear is driven at
constant rotary speed, every revolution of the
drive lasts for a specific period which is
described as cycle time. The amount of time
required to pass through the index angle is referred
to as index
time. Analogous to this, the amount of
time for passing through the dwell angle is referred
to as dwell
time.
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The rotary speed of the drive
is determinant to the attainment of a specific
cycle time. A modification of the cycle time
affects the index time and dwell time in the same
proportion at all times.
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To attain a specific index or
dwell time at a given rotary speed of drive, the
relation of the index to the dwell time must be
changed.
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The drive of the gear
forms a cam with a specially formed
profile. There are different cam types depending
on the construction type of the gear.
The
output is formed as a roller star or
rotary-table fitted with cam rollers..
The cam
rollers are attached to the profile of the cam. If
the cam is turned, the rollers follow the profile
and generate the motion of the output..
The
profile of the cam is formed in such a way that
this motion of the output corresponds precisely
with the specification of the motion law (see
above).
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