| 摘要 |
1,150,974. Conveyers. RAPISTAN Inc. 20 Oct., 1967 [20 Oct., 1966], No. 47741/67. Heading B8A. Movement of articles along a conveyer track is controlled by means which incorporates a time delay between the sensing of an article and the response of the control means. Thus the control means does not respond to the natural flow of articles but only to an unusual condition resulting from the cessation or substantial slowing of the articles. Rollers 12 of a rollerway 10 are driven by a belt 13 which is normally urged into engagement with the rollers 12 by pressure rollers 14. Pivoted hangers 15 for the rollers 14 are arranged in groups, the rollers of each group being raised by a pneumatic actuator 19 which receives air pressure, via a valve 31, from a conduit 32 common to all the actuators. An adjustable air bleed port (33), Fig. 3 (not shown) is -provided between each valve 31 and actuator 19. The valves are normally open, the actuators operated and the rollers 14 raised to cause drive by the belt 13. Sensing rollers 47, 47a, 47b control the valves 31 but each valve controls the actuator which is next upstream in the direction of movement of the conveyer. Thus, sensing roller 47a controls the position of the pressure rollers 14 of group B and sensing roller 47b those of group C. As shown, an article F has depressed roller 47b and the associated valve 31 has been closed. Since the article has remained on the roller 47b longer than a preset interval, e.g. from 2 to 5 seconds, escape of air through bleed port (33) causes the actuator 19 to retract and the belt 13, supported on rollers 14 of groups C, is allowed to drop. There is accordingly no drive immediately upstream of the stalled article. An article passing over a sensing roller at normal speed allows the roller to rise before the actuator responds to the closing of the valve 31. |
