Abstract
A suction-cup vacuum gripping tool comprising one tool-change interface, one suction cup, one ejector and one vent valve. When the suction cup reaches the workpiece, the suction cup is evacuated by the ejector. Before the workpiece reaches the set-down position, the vacuum circuit is vented by the vent valve while the workpiece is above the receiving surface. The arrangement is a proposed configuration composed from a typed library of mechanism blocks derived from published patents; it has not been constructed.
1. Purpose and arrangement
[0001]This disclosure describes a suction-cup vacuum gripping tool: one suction cup carried on a tool-change interface, fed by an ejector. It is arranged for controlling the moment of release and exchanging the tool without rewiring the cell. One concrete embodiment is described; every connection is stated with the medium it carries, and the operating sequence is given as conditions on named operations.
2. Components, construction and connections
[0002]One tool-change interface. The tool-change interface splits the tool into a robot side and a tool side, so the tool can be exchanged without dismantling it. The tool-change interface has a mechanical lock.
[0003]One suction cup. Each suction cup presents a sealing lip to the workpiece and is evacuated through its own connection. The suction cups are of the oval form.
[0004]One ejector. The ejector draws the circuit down by passing compressed air through a nozzle; it has no moving part at the tool and consumes air for as long as it runs. The ejector has two stages.
[0005]One vent valve. The vent valve opens the circuit it is connected to towards atmosphere, which ends the grip. The circuit is vented before set-down.
[0006]The suction cup is carried on the tool side of the tool-change interface.
[0007]The ejector is fixed to the tool side of the tool-change interface.
[0008]The suction cup is connected to the ejector outlet by a single vacuum line, so that the face is evacuated through that line.
[0009]The vent valve is connected to the circuit at the ejector outlet and opens that circuit to atmosphere when it is actuated.
[0010]The robot side of the tool-change interface is bolted to the robot flange.
[0011]The ejector is fed from the compressed air supply of the cell.
[0012]The vent valve is switched by the cell controller.
3. Operating sequence and conditions
[0013]
- When the suction cup reaches the workpiece, the suction cup is evacuated by the ejector.
[0014]
- Before the workpiece reaches the set-down position, the vacuum circuit is vented by the vent valve while the workpiece is above the receiving surface.
[0015]
- The workpiece is held until the vent valve has opened the circuit.
[0016]The cell controller commands the vent valve; no sensor drives an actuator directly.
4. Parameters and operating assumptions
[0017]Parameter values of this embodiment: locking of the tool-change interface: mechanical (sets what has to be present at the interface for the tool to stay attached); form of the suction cup: oval (sets the shape of the contact area and the behaviour of the lip on a curved workpiece); material of the suction cup: polyurethane (sets the friction at the lip and the tolerance of the lip to oil and heat); stages of the ejector: two (sets the flow drawn at low vacuum and the compressed air consumed while a sealed face is held); timing of the vent valve: before set-down (sets whether the workpiece is released before or after it is supported by the set-down surface).
[0018]The workpiece is released while it is still above the receiving surface and falls the remaining distance onto it. This sequence is for a workpiece and a receiving surface that tolerate that drop, for example a part released into a container or onto a conveyor; the drop height is set by the application and is not fixed here.
[0019]The lock is engaged by a manually operated lever on the interface; no supply crosses the interface for the lock, and tool exchange needs an operator at the tool.
5. Provenance and status
[0020]This document is an original combination composed from a typed library of mechanism blocks. Each block was derived from a published patent and carries typed connection points, the parameters its source states, and its own construction and operating description. The combination described here is proposed and has not been constructed. The published documents behind the blocks used in this arrangement are US-11858125-B2, US-2016214812-A1, WO-2008134339-A4; their text is not reproduced, and the description above is generated from the structure of the combination.