Build Instructions for Middle Finger

BUILD INSTRUCTIONS FOR MIDDLE FINGER

List of parts needed to assemble middle finger of bionic hand

3D Printer PartsQty
Middle_Part_11
Middle_Part_21
MIddle_link2
Palm1
Actuator_link1
Actuator_support_bottom1
Metal Parts Qty
Pin I1
Pin II1
Pin III1
Pin V2
E-clip I6
E-clip II4
Screw and Nut1
Electronic Modules Qty
Actuator1

In this section, we assembling middle finger and attaching to palm part

 Middle_link and Actuator_link were given as 3D print file. But if it is made as stainless steel from machine shop then the strength and durability of link can be prolong.

point 1a
point 1b

Pins I to IV can be made from 2.5 mm diameter stainless steel rods. Similarly, Pin V  can be made from 1.5 mm diameter stainless steel rods.  All pins was cut to length as specified in the DATASHEET. To fit e-clips on ends of the pins, the grooves are made with hack saw blade and drilling machine.   

point 2a
point 2b

Now we are going to assemble middle finger parts to palm

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Step 1

Redrill the Middle_part_1, Middle_part_2 and Palm holes to easy fit the metal parts. But ensure the use of right size of drill bit ­for redrilling. In our case we used 2.5 mm drill bit for larger hole and 1.5 mm drill bit for smaller hole.

step 1
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Step 2

Attach Middle_links to Middle_part_1 using Pin V and arrest movement by attaching
e-clip II to grooves.

step 2
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Step 3

Attach Middle_part_1 to Middle_part_II using Pin I with torsion spring I in center.

step 3
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Step 4

Attach e-clip I on grooves at end of Pin I

step 4
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Step 5

Place Torsion spring II in grooves on sides of Middle_part_II

step 5
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Step 6

Drill the holes with 1.5 mm drill bit in palm to insert other end of Torsion spring II

Step 6
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Step 7

Attach Middle_part_2 to palm with Pin II and attch Middle_links to palm. Ensure e-clip I was attached to ends of pin II and e-clip II was attached to Pin V.

Step 7
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Step 8

We are going to attach actuator to middle finger. Before doing this, we are going to convert this from servo motor to DC motor. To do this, we remove the flexible PCB inside the actuator and convert into normal DC motor.

step 8
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Step 9

Attach Actuator_link to Actuator with Pin III and e-clips.

Step 9
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Step 10

Glue the nut (2 mm) in the groove of palm.

Step 10
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Step 11

Attach actuator to finger_part_2 and place in palm with actuator_support_bottom.

Step 11
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Step 12

Attach actuator_support_bottom to actuator and place in palm with screw

Step 12
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Step 13

Steps 1 to 9 are similar to assemble all fingers. Ring finger can attach to palm as similar to middle finger as shown in step 12.

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Step 14

Index and small fingers can attach to palm using side supports with screw and nut.   

step 14