Abstract
A bellows-cup vacuum gripping tool comprising one tool-change interface, two bellows cups, one ejector, one manifold, one pressure sensor, one contact detector and one vent valve. When the bellows cups reach the workpiece, the bellows cups are 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 bellows-cup vacuum gripping tool: two bellows cups carried on a tool-change interface, fed by an ejector. It is arranged for verifying that the workpiece is held before the arm moves, starting the cycle at the moment of contact, controlling the moment of release, taking up height differences at the face 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]Two bellows cups. Each bellows cup is folded so that it shortens under vacuum and takes up a height difference between the face and the workpiece. The count of two follows from the arrangement: one gripping element per manifold outlet. Each bellows cup has one fold.
[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 one stage.
[0005]One manifold. The manifold receives the vacuum at one inlet and distributes it to its outlets. The manifold has two outlets.
[0006]One pressure sensor. The pressure sensor taps the line it is placed in and reports the vacuum level in that line. The pressure is measured in the supply line.
[0007]One contact detector. The contact detector reports the moment a workpiece is present at the gripping face; its sensing technology is not fixed by this arrangement. The contact detector is mounted on the gripping face.
[0008]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.
[0009]The bellows cups are carried on the tool side of the tool-change interface.
[0010]The manifold is fixed to the tool side of the tool-change interface.
[0011]The ejector is fixed to the tool side of the tool-change interface.
[0012]The manifold inlet is connected to the ejector outlet, which supplies every outlet of the manifold.
[0013]Each manifold outlet feeds one bellows cup by its own vacuum line, so that the two outlets feed two bellows cups.
[0014]The pressure sensor is tapped into the line between the ejector and the distribution and reads the pressure of the whole circuit.
[0015]The contact detector is mounted on the gripping face and reports the moment a workpiece is present against the gripping face.
[0016]The vent valve is connected to the circuit at the ejector outlet and opens that circuit to atmosphere when it is actuated.
[0017]The robot side of the tool-change interface is bolted to the robot flange.
[0018]The ejector is fed from the compressed air supply of the cell.
[0019]The vent valve is switched by the cell controller; the pressure sensor and the contact detector report to the cell controller.
3. Operating sequence and conditions
[0020]
- After the contact detector has detected the workpiece, the vacuum supply is actuated by the cell controller.
[0021]
- When the bellows cups reach the workpiece, the bellows cups are evacuated by the ejector.
[0022]
- When the vacuum level exceeds the gripping threshold, a secure grip is signalled by the pressure sensor.
[0023]
- The workpiece may not be lifted unless the pressure sensor signals a secure grip.
[0024]
- 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.
[0025]
- The workpiece is held until the vent valve has opened the circuit.
[0026]The cell controller reads the pressure sensor (the common supply line) and the contact detector (on the gripping face) and commands the vent valve; no sensor drives an actuator directly.
4. Parameters and operating assumptions
[0027]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); folds of the bellows cups: one (sets the travel taken up between the face and the workpiece, and the lateral stiffness of the cup under load); material of the bellows cups: plastic (sets the friction at the lip and the resistance of the folds to fatigue); stages of the ejector: one (sets the flow drawn at low vacuum and the compressed air consumed while a sealed face is held); outlets of the manifold: two (sets how many lines can be fed from one inlet); placement of the pressure sensor: in the supply line (sets where in the circuit the reading is taken and what it describes); placement of the contact detector: on the gripping face (sets where the presence of the workpiece is detected); 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).
[0028]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.
[0029]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.
[0030]Vacuum levels are stated as gauge pressure below atmosphere. A stronger vacuum is a larger pressure difference below atmosphere, and the vacuum level 'exceeds the gripping threshold' when that difference is at least the threshold difference.
5. Provenance and status
[0031]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 EP-4489564-B1, US-11427405-B1, US-11858125-B2, US-2022339798-A1, US-8006968-B2, WO-2008134339-A4; their text is not reproduced, and the description above is generated from the structure of the combination.