Pneumatic Arm Step-by-Step

Pneumatic Arm
Assembly Instructions
Contents of Pneumatic Arm Kit
Wooden pieces (⅜” cross-section): 1 X 24”; 1 X 21⅛”; 4 X 7”; 2 X 4⅞”(each cut into two
smaller pieces at an angle); 1 X 3”; 1 X 2¾”; 4 X 2⅜”; 4 X 2”;
2 X 1½”; 3 X 1¼”; 7 X ¾”
Green corner gussets: 3 cards
Syringes, 20cc: 4 (2 have holes in the plunger, 1 of which is trimmed)
Syringes, 10cc: 2 (1 has a hole in the plunger)
Plastic Tubing: 1 length approx. 6ft.
Wooden dowel, 3/16” diam.: 2 X 3½”; 1 X 2½”; 3 X 2⅝”; 3 X 1½”; 1 X 1⅛”; 1 X ¾”
Wooden dowel, 7/8” diam.: 1
Axle Holders: 18; Mini-washers: 11
Syringe Holders: 3
Stirring Sticks: 2; Rubber bands: 2
Platforms: 2 (both drilled, 1 trimmed); Objects: 2 x 3”(1 round, 1 square)
Wheel with 7/8” hole; Small wheel sub-assembly
Wooden base with wheels fixed in place
Plus a piece of sandpaper
Kit Contents
Assemble the two “fingers” that make the claw. Two pieces are used for each finger and
they are both cut at an angle at one end. The smaller of the two pieces has two holes. For
each finger glue the two pieces together and reinforce them using strips of cardboard cut
from the edges of a green corner gusset sheet.
Using the two longest pieces, one 24” long and the other 21⅛” long with a hole at one
end, and 7 short pieces each ¾” long, assemble the arm structure. Glue a ¾” piece at the
“even” end and pieces 2”, 3½”, 9” and 16½” from the same end, securing with green
gussets as shown. Glue the gussets on one side first.
On the other side glue another ¾” piece ⅛” from the end piece as shown below.
Lastly glue the remaining ¾”piece next to this last piece towards the “even” end.
Secure the ¾” pieces with gussets and use the two elastic bands to hold the arm in
position while the glue dries.
Using 4 pieces each 2⅜” long and 8 corner gussets, 4 on each side, assemble a 2¾” square
as shown. Allow the glue to dry on each side. Create 4 “double gussets” and glue these
onto the corners of the square.
To begin to assemble the tower structure that will house the arm you need 4 pieces 7”
long, 4 pieces 2” long, 3 pieces of dowel 2⅝” long and one ¾” long.
The 7” pieces have a hole drilled in their base. To begin assembly, glue the 4 dowels into
these holes making sure that they protrude equally and are as straight as possible
Using the 2” pieces create two forms as shown below, using 16 gusset corners to secure
the pieces. The top edge of the 2” cross members are 2” and 5” from the top end, the
ends without dowels.
While these dry glue the wheel with the 7/8” hole onto the “untrimmed” platform using
the 7/8” dowel as guide. Then glue the dowel into the hole – it will flush with the wheel
on the topside.
Once the forms are dry carefully insert the “legs” through the four holes in the platform,
as shown – the shorter dowel may not protrude. Finish the “tower” structure by
“capping” the four ends at the top of the tower with the 2¾” square. The “double”
gussets are glued in and house the four “loose” ends.
Glue into place two axle holders on each side of the four cross members of the “tower”
structure. Use the two 3½” axles to align the set of four axle holders so that they are
perpendicular to the structure and that they turn freely. Note the alignment of the axle
holders – they “point” towards each other.
Glue 4 axle holders so that their holes are 14” from the “even” end of the arm structure. It
is useful to mark the axle holder where the centre of the hole is and align this with a
measure on the arm. It is important that all the holes align and that they are
perpendicular to the sides - use an axle to check. Similarly glue 4 more axle holders 11”
from the “even” end. Place the arm on one side and allow the glue to dry thoroughly.
Glue the 1⅛” dowel into the smaller wheel sub-assembly so that it is flush with the side
with the white card disk. Remove the backing from a syringe holder and secure firmly in
the center of the white card disk
To make the syringe platform use 3 pieces each 1¼” long. Glue them together along the
long side and cut out two strips of green card and glue to form a platform 1¼” X 1⅛”.
Glue two axle holders as shown making sure that the holes are aligned and
perpendicular to the short side. Trim the edges of the axle holders off.
Carefully insert the plunger of a 20cc syringe - one that is not cut – onto a long leg
adjacent to the short or “missing” leg. Carefully place the second “trimmed” platform
onto the legs and the 7/8” dowel.
Place the tower, with the second “trimmed” platform acting as ballast, onto the base by
inserting the 7/8” dowel into the large wheel on the base. Ensure that the tower rotates
freely. Insert the small wheel sub-assembly into the small wheel on the base. Carefully
insert the plunger into the barrel of the 20cc syringe and push that barrel into the syringe
clip as shown. The lip of the barrel will sit just over the edge of the white disk.
Firmly place a syringe clip onto the 1¼” X 1⅛” platform and, using a 3½” axle, mount the
platform in the middle of the tower using the lower set of axle holders, then finish with 2
mini-washers. Select the syringe that has the cut plunger and place this syringe into the
clip. The cut plunger will be connected to the arm once the arm is mounted into the
Glue the 2¾” piece between the two fingers of the claw and secure with a strip of green
cardboard. Use a dowel to align the holes of the claw as shown.
Glue a 3”strip of green cardboard along the inside of the 24” piece. Glue a 1½” dowel
into the hole of the 3” piece that is ¼” from one end.
When the glue is dry, use the remaining two 1½” dowels to connect the claw to the arm
as shown. No glue is used, the pieces are secured by the axles and four mini-washers.
Check that the claw opens and closes freely. Your claw may be left or right handed
Firmly place a syringe clip onto the arm where the two ¾” pieces are glued together but
not over the ⅛” gap. Select the 10cc syringe with a hole in its plunger and push the
plunger onto the 1½” dowel and the barrel of the 10cc syringe into the syringe holder.
The lip of the barrel fits into the ⅛” gap. Finish with a mini-washer.
Using a 3½” axle, mount the arm into the tower using the set of four axle holders nearest
the top. Using the 2½” axle and the 20cc syringe with the cut plunger connected to the
syringe platform carefully extend the plunger and connect to the remaining four axle
holders on the arm. Finish with two mini-washers.
Finally use two pieces each 1½” long and glue them onto the arm, 3” apart, at the end
without the claw.
The wooden block may be placed between them to act as a counter-weight.
Use two 18” lengths of tubing for the 20cc syringes and the remaining length for the 10cc
syringes. When connecting these ensure that the plungers are complementary, i.e. if the
arm is at its lowest point the syringe on the syringe platform will be closed so its
connecting syringe will be open.
The arm will be capable of picking up an object, rotating and placing it elsewhere:

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