Christmas socks ---- shoot the present a year ago

Do you know why Christmas gifts always appear at night when people all fall asleep? Because there’s a little elfin who’s too shy to show up when people are awake. Santa Claus sends the elfin to bring children presents. If children wake up at night, the elfin may feel nervous and pop the presents out of the Christmas socks accidentally. Ohhhhh my Christmas socks can shoot off Christmas present!

Constructing Steps

Christmas socks

    What’s this? My Stocking is shooting out the presents on it’s own?



 The inner mechanisms are as shown below.

 There is an ejection device to shoot the presents right out of the stockings!



  Here to introduce some kinds of simple ejection devices, we will use the one that is more effective for this project.



     Pulled by a cam (Figure on the left) and by pinion or rack (Figure on the right)

     We can assume the pulling structure on the right have the pulling force about 10 newtons.


The figure above is a working position of the devices .

The red line is the real position of pull rod.

Bule line is the vertical force and horizontal force.


As the figure shows:

Vertical force is about one-tenth of horizontal force. The horizontal distance of working point and the rotating center is about one-third of the radius.

The vertical distance of working point and the rotating center is about one-fifth of the radius.

If we ignore the torque provide by vertical force, have the same driver, using cam, the pulling force can be about five time as the pinion or rack device can provide.


Producing steps is under the spilt line.


The follow picture shows all the parts it need.

It looks like a large pile of parts, but things get put together pretty quickly once you get started.


##STEP1##: Assemble the ejection mechanism as the picture below.(Don’t forget the springs!)

##STEP2##: Assemble the rotatable underbed. Black gears just work as bearings, it may be a waste...

##STEP3##: The cam mechanism to pull and put off the ejection mechanism, driven by motor.

##STEP4##:Assemble the three components you have made and we are starting to get things rolling, it can now eject stuff!

##STEP5##:Assemble of movable support frame.: 

   Assemble the wheels as Fig.1;

   Prepare the extra parts as Fig.2 show and put them together become in Fig.3;

   Put on electric parts as Fig.4.

Reference figure ---1

  The details about connect support frame and the ejection mechanism.

##STEP6##:It need a path for ejection.

   I have made one using "linkage 080", it may look simple but it really works.

##STEP7##:Shape it like a stocking and you’re good to go!


  • Project Difficulty Level
  • Required Skills
    Software Machinery Electronics