Abstract: A bowling alley is provided with a photoelectric pinfall detection system which includes a pinfall detection device by means of which it can be recognized whether or not a fallen pin is lying in the end region of the bowling lane or in one of the gutters. The pinfall detection device comprises a light sensitive sensor array which detects any radiation reflected by a pin lying in the end region of the bowling lane. For this purpose, the lower foot portion of each pin may be provided with a black ring. Thus, the reflection characteristics of the pin change in dependence whether the pin is standing upright or has fallen, because in the first case the weak reflection of the black ring is detected by the pinfall detection apparatus, while in the second case the strong reflection of the white central portion of the pin is detected.

Abstract: The invention provides a photoelectric bowling pinfall detection system which automatically scans and displays the number of the knocked down pins after each ball delivery. The system comprises an emitter positioned offset to the central longitudinal axis of the bowling lane in a certain distance to the pin arrangement, which emits a sharply focussed beam towards the pins. A receiver is provided behind the pins which detects the receipt of the focussed beam. If the beam is swept along the pins, each standing pin causes an interruption of the beam which is recorded by the receiver and fed to a processing circuitry. From the output signals of the receiver information about the numbers of the knocked down pins is derived and displayed.