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The first mechanism is based off of a scissor lift, and allows the grabbing head to articulate forward. It's comprised of 8 links which are 3D printed out of ABS plastic. 3D printing the links instead of laser cutting them out of acrylic, allows Rather than using laser cut acrylic links, these 3D printed links allowed us to tune the fit of the bearings, allowing providing a precise press fit. The ABS plastic is also relatively light weight and stiff. Each link has 3 inexpensive RC car bearings, which provide for low friction actuation. In order to prevent the links from rubbing together, they are separated by a 1mm thick ABS spacer. The links are joined together with 5mm stainless steel pins, which were manufactured in the machine shop.
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The controls for the device are attached via industrial velcro Velcro at the back of the brace. The velcro Velcro allows for the controls to be moved around and replaced if need be. The controls feature a toggle switch for each mechanism, which allows closed and open movement. An on/off switch on top stops all movement of the device. Excluding the connections to the Arduino, all of the connections are soldered for reliability.
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