| 摘要 |
<p>A cash desk has a set of pigeon holes protected by a rigid steel shutter which moves silently up and down to protect the contents, activated by an electric motor. The shutter can either be in an upper position, when the pigeon-holes are closed or a lower position when the cashier has access to them. The shutter has along each of its vertical edges, a toothed rack connected to a pinion which the motor drives by means of an irreversible reversing gear mechanism. Both rack and pinion are made of plastics to reduce noise to a minimum. The shutter has a small rubber guide which runs silently on vertical tracks.</p> |
