A Chinese finger trap (also known as a Chinese finger puzzle, Chinese handcuffs and similar variants) is a gag toy used to play a practical joke on children and unsuspecting adults. The finger trap is a simple puzzle that traps the victim's fingers (often the index fingers) in both ends of a small, woven bamboo cylinder.
Contents |
The initial reaction of the victim is to pull the fingers outward, but this only tightens the trap much more. The solution to escaping the trap is to push the ends inward toward the middle, which enlarges the openings and frees the fingers, before slowly twisting them out of the trap so as not to trigger the tightening reflex again. A second form of escape is to push one's fingers together and then grab the ends of the trap with one's middle fingers and thumbs. The fingers can then easily be pulled out.
The tightening is simply a normal behavior of a cylindrical, helically wound braid, usually the common biaxial braid. Pulling the entire braid lengthens and narrows it. The length is gained by reducing the angle between the warp and weft threads at their crossing points, but this reduces the radial distance between opposing sides and hence the overall circumference. The more one pulls, the more the circumference shrinks (i.e. the trap tightens). The same effect is used in specialized textile manufacturing, electrical contractors' wire-pullers, Indonesian woven fruit presses, and by fly-fishers.
Chinese finger traps are not intended for use as restraint devices. Strong victims of the prank may break the bamboo strips when they pull outwards, attempting to free their fingers and stretching the trap beyond its limits. However, a variation on the Chinese finger trap used in orthopedic medicine—namely, providing even pressure to the patient's digit(s) and at the same time immobilizing the joints—serves a similar purpose as a traction device.
The Chinese fingers traps is also a common metaphor for a problem that can be overcome by relaxing, i.e., not trying too hard to solve it, or for a belief system that includes punishment for disbelief in itself. For example, in Acceptance and Commitment Therapy.
The finger trap can be seen in a number of films and television programs, such as the Stan Laurel short "Dr. Pyckle and Mr. Pryde" (1925), the Little Rascals short "Moan and Groan, Inc.", the Star Trek: The Next Generation episode "The Last Outpost" (1987), the feature film The Addams Family (1991), Chasing Amy (1997), 100 Women (2002), Mulan II (2005), Dexter's Laboratory (episode Unfortunate Cookie), Foster's Home for Imaginary Friends (episode The Big Leblooski) and the Simpsons[1].