07 February 2016

2.77 Seek and Geek #1: Apple Lathe

Seek and Geek #1: Apple Lathe

I discovered this wonderful tool in my living group's kitchen. It's used to simultaneously peel and core an apple. 

The lathe can be attached to any smooth surface using a suction base. By turning the handle, a channel underneath the lathe pulls up and creates negative pressure that keeps it against the surface. 

Here, my girlfriend models the machine in action. The apple is held by three skewers at the end of a screw. The screw is actuated by a handle at the back end. By turning the screw, the apple both spins and moves forward, enabling the spring-loaded cutting tool to peel the apple, and the blade at the far left to remove the core. 

This spring-loaded tab disengages the screw and enables it to be pushed back without having to turn. 

By letting go of the tab, the screw engages and must turn in order to move linearly. 

St. Venant's principle in action! The screw is supported by two linear bearing blocks. The distance between them is equal to at least 3-5 screw diameters! No jamming occurs, the motion is smooth. 

The blade at the end that removes the core also allows the apple flesh (the desired output of this machine) to spiral out in one long piece. 

The cutting tool for peeling is normally spring-loaded against the apple to apply cutting force. In order to insert the apple, however, it must be positioned out of the way. There is a small tab near the bottom, with an adjustment screw, to block the cutting tool from coming down as you insert the apple. 

Pushing it aside once the apple is inserted brings the cutting tool to its ready position. 

The cutting begins!

The pitch of the screw matches the width of the "chips" coming off of the apple peeler. 

Such lovely chips! The apple begins to pass through the blade that will remove the core and remove the flesh in a spiral. 

Nearly done with the operation! The spring-loaded cutting tool compensates for a wide range of apple sizes and diameters by being constantly loaded onto the apple with a spring. Note that proper alignment of the apple on the skewers is vital for removing the core cleanly. This is the only failure mode I've seen, sometimes the apple will be pushed off of its skewers if sufficiently misaligned. The blades seem to be removable for easy replacement or cleaning. 

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