Modifying equipment

When hired mechanical props are required to perform in vision, they are invariably modified by effects technicians. Typical are gaming machines, coffee makers, lawn mowers, washing machines and so on. Problems are quite often encountered when these devices are wanted to operate ‘normally’.

A typical example might be a gaming machine required to deliver its jackpot. Whether the old fashioned one-armed bandit or the later illuminated display machine, these devices are highly complex and to make them work on cue is by no means easy.

Cloned functions

If coins are to pour from a gaming machine it is sometimes simpler to insert a dummy chute from which coins are tipped in from behind. In some cases a close-up shot of a dummy area of the front could make the point more dramatically (and more easily), with the camera returning to the real machine knee deep in money.

A coffee dispenser (whether normal or pantomime) can be given a false nozzle which is fed from an overhead container or pressurised fire extinguisher. Washing machines that have to flood can be fed backwards through the drain hose.

Shaking equipment

If a large item, such as a washing machine, has to go violently out of control, it is sometimes a good idea to fix it to a sub-baseboard. The prop can be fastened to the baseboard by large coil springs of the type used in upholstery. The baseboard can then either be secured to the floor or held down by stage-weights.

To make the machine shudder, an electric motor fitted with a suitable gearbox and cranked arm can be used to impart the necessary oscillations. The arm should be passed through the bottom of the washing machine and connected to the baseboard.

Alternatively, the motor can be fitted with a cam in contact with a spigot that passes through the bottom of the machine.

One method of producing vibrations without any external mechanical connections is to equip the motor with an off-centre weight. Fixed to the spindle the weight produces either high speed vibrations or low speed shaking according to its size and the power of the motor.

To show an alarm clock vibrating madly as the bell goes off, the eccentric weight can be fitted to the spring mechanism.

SHAKING EQUIPMENT

1. Large items that have to shake should be mounted on springs.

2. A motorised arm and crank will vibrate small items.

3. An eccentric weight on a motor shaft produces violent oscillation.

4. Two chemicals that will foam on being mixed may be introduced into a bottle by lifting the containers