| 摘要 |
A signalling device for detecting and signalling the presence of articles on the bottom package tray (20) of a shopping cart as the shopping cart is moved through an aisle adjacent a checkout station (72) comprises a pair of springs (40, 42) positioned at the forward end of tray (20) and operative to bias tray (20) in an upper position relative 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 as the cart is moved alongside checkout station (72). A reflector (60) is mounted on bottom tray (20) proximate the rear end thereof and is oriented to reflect light directed toward one side of the cart. Reflector (60) is normally biased in an upper postion and is movable to a lowered 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 attendant that merchandise is present on tray (20). A method for adapting an existing shopping cart for use with a signalling device for detecting and signalling the presence of articles on the bottom package tray of the cart includes the steps of hinging the tray to the frame to permit vertical movement of the tray and spring biasing the forwrad end of the tray to normally maintain the tray in an elevated position and to permit the tray to move to a lower position when an article is placed on the tray. A reflector is releasably coupled to the tray and oriented to reflect light directed at it from the signalling device. |
