GB1397614A - Article pick-up assembly - Google Patents

Abstract

1397614 Suction lifting devices EATON CORP 12 April 1972 [15 April 1971] 16871/72 Heading B8H [Also in Division F2] A pick-up assembly for use in moving articles comprises a pick-up head (10) having an array of suction cups (20), the head (10) being mounted on a stacker crane (12), Fig. 1 (not shown), each cup 20 having a control assembly 34 associated therewith whose function is to maintain those cups 20 of the array which are in engagement with an article to be lifted in communication with a vacuum source, but to ensure that those cups 20, which are not in engagement with the surface of an article, are not in communication with the said vacuum source. When the suction cups are in engagement with the surface of an article to be lifted a plurality of switches are closed, each switch 110 being in an electrical circuit 100 in the control assembly 34 of each cup 20, Fig. 7. The closing of a switch 110 activates an oscillator 112 which delivers a pulse P1 of a predetermined duration to a solenoid 54 which causes a plunger 56 associated therewith to be moved to the left in Fig. 3 thus opening a ball valve 48 against the action of a spring 60 and permitting air to pass through a passage 38 to a low pressure chamber 44 which is in communication with the vacuum source. If a particular cup 20 is in sealing engagement with an article the pressure in the associated passage 38 drops and a cylindrical plunger 72, whose one end is in communication with the passage 38 and whose other end is in communication with the atmosphere through a passage (90), Fig. 4 (not shown), is moved to the left in Fig. 2 thus depressing an actuator button 78 in a switch 68 which closes and thereby connects the associated solenoid 54 to a D.C. source, Fig. 7, the solenoid 54 maintaining the associated valve 48 open by means of the plunger 56 at the end of the period of the pulse P1. In order to release the cup 20 from the article a switch 120, Fig. 7, is opened to interrupt the flow of current to the solenoid 54, the plunger 56 retracting and the ball valve 48 resetting under the action of the spring 60. If on the other hand a particular cup 20 is not in engagement with an article, on actuating the associated solenoid 54 by means of the pulse P1 the valve 48 is opened by means of the plunger 56 but as the passage 38 is in communication with atmosphere there is no difference in the pressure at the two ends of the associated plunger 72 which therefore does not move to actuate its switch 68, and at the end of the pulse P1 the plunger 56 is retracted thus allowing the ball valve 48 to reset, thereby closing off the passage 38 from the vacuum source. Associated with each cup 20 is an indicator lamp 134, Fig. 7, mounted on a display panel, Fig. 8 (not shown), such that when the associated switch 68 is closed owing to the engagement of the cup with an article the lamp 134 is lit.