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The
Elekit ROBOT ARM has five separate movements to grab/release,
lift/lower, rotate wrist and pivot sideways controlled by
the five switches on the wired controller. Robot Arm
introduces the fundementals of robotic sensing and the basic
principles of mechanics. The transparent arm and LED lights
allow you to observe gear mechanisms and their movement.
The manual provided along with the Robot Arm contains
a detailed description of the components and full instructions
on assembling the arm, together with an explanation of the
mechanisms involved and a brief history of robots.
<<
The completed Robot Arm with its controller
The
Robot Arm holding a full sized screwdriver >>
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At first
sight, the assembly of the Robot Arm might perhaps look
a daunting task, due to the large number of component parts
involved. If the instructions are followed carefully, however,
the project can be completed with relative ease, although
special care should be taken with the wiring sections.
<<
Some of the many components of the Robot Arm, including
the five power units which operate each of the five functions.
The
remaining components, including the base/battery box, arm
sections and control panel PCB can be seen in the photograph
on the right.
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This
photograph shows the five power units. As can be seen, each
unit has different coloured wiring, and care should be taken
to ensure that the correct unit goes in the correct place
on the arm. It should also be noted that these units have
been oiled. so care must be taken to not get any on your
hands when handling them.
The
photograph on the right is a close-up of power unit P-1,
with its green and white wires, showing its internal gears
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The
first step is the wrist assembly.
The parts used in the assembly of the wrist mechanism can
be seen in the photograph on the left, incluing power unit
P-1 with its green and white wires.
The
two fingers should be assembled as per the detailed instructions
in the accompanying manual, ready for attachment to the
wrist unit. Note: assembly and function are not affected
should the projections get broken when separating finger
links and bases.
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Attention
should now turn to the power unit. The attached bulb should
be inserted into its bracket on the power unit, hooking its
wires through the front of the holder to secure them, and
then the clutch gear A and small spacer mounted onto the drive
axle and secured with an M3x12 tapping screw. This screw should
not yet be fully tightened.
The assembled finger section with the rack gear can now be
engaged with the clutch gear of the power unit (see diagram
in manual). The tapping screw should now be tightened to the
point that the rack gear can move smoothly engaged with the
clutch gear.
The unit is now mounted onto part A of the wrist cover, mounting
the power unit onto the small posts in the cover. The second
finger assembly should now be inserted, engaging the teeth
of the gear with those of the other finger gear.
Once the finger assemblage is complete, the other wrist cover
is screwed in place with two M3x12 tapping screws, making
sure that the wires are not pinched.
The wires can now be put across a D sized battery to check
operation of the fingers and any adjustments made if necessary,
following guidance of the manual. |
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If
you are happy with the operation of the finger/jaw unit, the
next stage is the assembly of the wrist-rotate and forearm.
The white clutch and rotor stoppers are installed first, making
sure that the triangular marks on both wrist and clutch stopper
line up, when the pieces should simply snap into place. Be
certain not to pinch the wires from power unit P-1. The clutch
stopper is secured in place with an M3x12 tapping screw, which
should be screwed in so that the head is slightly below the
surface of the stopper to prevent interference with wrist
movement.
Both wires should be marked at approx 5cm from the base and
fitted in the slits of the rib of Forearm A, to allow sufficient
movement of the wrist. The right hand photograph clearly shows
the resultant loop of wire between the clutch stopper and
the rib. The wires can then be put through the opening at
the top end of the Forearm and fitted in the slits in the
second rib.
The clutch plate can now be fitted to the wrist section, putting
the wires around each side as illustrated in the manual. |
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The
next stage is to fit the second power unit P-2 (with blue
and green wires) and the wrist into the forearm A, carefully
aligning the gear on the power unit with that on the clutch
plate so that they engage properly. P-2 is secured in the
Forearm by small hooks. Once the power unit is firmly in
place, the light bulb can be placed in its holder in the
forearm, taping its wires onto the motor if they are too
long. The photograph on the left shows the wrist and forearm
with the power unit in position.
The
cover (Forearm B) can now be fastened in place with 3 M3x12
tapping screws, making sure that none of the wires are pinched.
As before, connect a D sized battery across the wires to
check correct movement - the arm will turn right if the
blue wire is connected to the (+) and the green wire to
the (-), and will turn left if connected in reverse.
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The
joint between the forearm and the upper arm has a rather
more substantial clutch, which is in fact made up of a clutch
gear sandwiched between two felt pads and two metal clutch
disks, all of which can be seen laid out in the photograph
on the left.
The
right hand photograph shows the completed clutch assembly,
which is held together by an M3x25 screw.
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