Abstract
A bellows-cup vacuum gripping tool comprising one mounting flange, three bellows cups, one ejector, one isolation valve, 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. After the workpiece has reached the set-down position, the vacuum circuit is vented by the vent valve. 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: three bellows cups carried on a mounting flange, fed by an ejector. It is arranged for cutting part of the circuit while the rest holds vacuum, verifying that the workpiece is held before the arm moves, starting the cycle at the moment of contact, controlling the moment of release and taking up height differences at the face. 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 mounting flange. The mounting flange carries the whole assembly and presents the bolt pattern that meets the robot.
[0003]Three 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 three follows from the arrangement: one gripping element per manifold outlet. Each bellows cup has two folds.
[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 isolation valve. The isolation valve sits in the line it controls; closing it cuts that line without disturbing the rest of the circuit. Isolation is common.
[0006]One manifold. The manifold receives the vacuum at one inlet and distributes it to its outlets. The manifold has three outlets.
[0007]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 at the manifold.
[0008]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.
[0009]One vent valve. The vent valve opens the circuit it is connected to towards atmosphere, which ends the grip. The circuit is vented after set-down.
[0010]The bellows cups are carried on the tool side of the mounting flange.
[0011]The manifold is fixed to the tool side of the mounting flange.
[0012]The ejector is fixed to the tool side of the mounting flange.
[0013]The isolation valve is placed in the line from the ejector, so that closing the valve cuts the whole circuit from the supply.
[0014]The manifold inlet is connected to the isolation valve outlet, which supplies every outlet of the manifold.
[0015]Each manifold outlet feeds one bellows cup by its own vacuum line, so that the three outlets feed three bellows cups.
[0016]The pressure sensor is tapped into the manifold body and reads the pressure common to every outlet.
[0017]The contact detector is mounted on the gripping face and reports the moment a workpiece is present against the gripping face.
[0018]The vent valve is connected to the circuit at the line downstream of the isolation valve and opens that circuit to atmosphere when it is actuated.
[0019]The robot side of the mounting flange is bolted to the robot flange.
[0020]The ejector is fed from the compressed air supply of the cell.
[0021]The isolation valve and the vent valve are switched by the cell controller; the pressure sensor and the contact detector report to the cell controller.
3. Operating sequence and conditions
[0022]
- After the contact detector has detected the workpiece, the vacuum supply is actuated by the cell controller.
[0023]
- When the bellows cups reach the workpiece, the bellows cups are evacuated by the ejector.
[0024]
- When the vacuum level exceeds the gripping threshold, a secure grip is signalled by the pressure sensor.
[0025]
- The workpiece may not be lifted unless the pressure sensor signals a secure grip.
[0026]
- After the vacuum level has exceeded the gripping threshold, the isolation valve is closed by the cell controller.
[0027]
- While the isolation valve is in the closed state, the vacuum downstream of the valve is maintained by the sealed gripping face.
[0028]
- After the workpiece has reached the set-down position, the vacuum circuit is vented by the vent valve.
[0029]
- The workpiece is held until the vent valve has opened the circuit.
[0030]The cell controller reads the pressure sensor (the manifold) and the contact detector (on the gripping face) and commands the isolation valve, the vent valve; no sensor drives an actuator directly.
4. Parameters and operating assumptions
[0031]Parameter values of this embodiment: folds of the bellows cups: two (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: two (sets the flow drawn at low vacuum and the compressed air consumed while a sealed face is held); control of the isolation valve: common (sets which part of the circuit the valve cuts: one branch line on its own or the whole circuit); material of the isolation valve: steel; outlets of the manifold: three (sets how many lines can be fed from one inlet); placement of the pressure sensor: at the manifold (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: after set-down (sets whether the workpiece is released before or after it is supported by the set-down surface).
[0032]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
[0033]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-10163334-B1, US-10549431-B2, US-11427405-B1, 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.