| 摘要 |
<p>A signalling device for detecting and signalling the presence of articles on the bottom package tray (20) of a shopping cart comprises a pair of springs (40, 42) located at the forward end of tray (20) and operative to bias tray (20) in an upper position relative to the frame of the cart. A photoelectric assembly (70) is positioned at a checkout station (72) and directs a beam of light (74) across the path of the shopping cart. A reflector (60) is mounted on bottom tray (20) proximate the rear end thereof. Reflector (60) is normally biased in an upper position and is movable to a lower position in the path of light beam (74) when an article is placed on tray (20). Photoelectric assembly (70) is operative to receive light reflected from reflector (60) and is responsive thereto to activate signal means located at the checkout station to indicate to the checkout clerk that merchandise is present on tray (20). In addition, a method for adapting an existing shopping cart for use with the signalling device is disclosed.</p> |
