Both in stage and close up magic, the magic effect of production of an object is always one of the most astonishing tricks to perform. We have seen champagne being produced in balloon, shoes inside a deck of cards and objects from the most impossible locations. A common approach to produce an object is by bringing it into the appearance position with high speed. It could be achieved with the use of thread, elastic chord or other materials.
Same principle can be applied on a prop with a lever. The object to be produced is first hidden and attached to the end of the lever. The lever is controlled by a spring and a switch to release the tension. Before the performance, the lever is pushed and the spring is compressed. They are held in this position with the object in the hiding place. When the magician touch the switch, the tension is released and the object is brought into the right place by the lever.
We see similar device being used in a classic stage effect called the Card in Balloon. The spring lever is set up behind a wooden stand. A card is glued to the lever. The lever is pulled back before the performance. The card is now hidden behind the stand. A balloon is put on the stand. Then at the right moment, the magician triggers the device, the lever swings up quickly and breaks the balloon. The card appears on the stand which looks like it was from the inside of the balloon.
In close up magic, we also see a number of examples utilizing this principle. The source of force to bring the object quickly can be gravity, centrifugal force or mechanical motor. In one phrase of the ring routine, Ring Leader by Greg Wilson, we see the use of gravity to bring in the ring rapidly. A classic coin trick by T. Nelson Downs demonstrates the use of centrifugal force. A magic wand is used here. The wand is prepared in a special way for the trick. One end of the wand slit open to about one inch. The split is opened to gain a larger diameter than normal.
The effect is to produce multiple coins with a very clean manner. Some special coins are used in this trick. Some a small ring is fused to the back of each coin perpendicularly. The rings are just large enough to pass through the wand but not the cut end. Therefore, a coin can be put onto the wand and concealed by the hand. When the magician swings the wand quickly, the coin is brought to the end of the wand quickly by centrifugal force. The split stop the coin from flying off.
Centrifugal force causes the individual coin to slide up the wand and jam at the "V." When the performer forces this coin over the "V", the sides of the split spring in and allow the coin to pass. This is repeated until all the coins have appeared. Of course, this principle may be applied to any long thin object such as sticks, canes, swords. And the objects to be produced are limited only by the size of the concealment space available.